JP2010102969A - Transmission device for illumination light communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new illumination light communication system having a high performance as illumination and a fast communication speed, and a transmission device suitably applicable for this illumination light communication system. <P>SOLUTION: This is the transmission device for illumination light communication system having an illumination light source which emits modulation light modulated based on transmission data. The illumination light source has a substrate 51 having light transmission property and an organic electroluminescent element 26 which is installed in contact with the substrate. The organic electroluminescent element has a first electrode 52 which has light transmission property and is arranged in contact with the substrate, a second electrode 58, and a luminous layer 56 which is installed between the first electrode and the second electrode. When the refractive index of the first electrode is made n1 and the refractive index of the substrate is made n2, the absolute value of (n2-n1) is smaller than 0.4 (provided that, n1≤1.8). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination light communication system that transmits data using illumination light and a transmitter that can be suitably applied to the illumination light communication system.

  With the progress of high-speed communication technology, indoor wireless communication technology using light as a transmission medium has come to be used. In particular, LAN (Local Area Network) using infrared rays as a transmission medium has become widespread in offices and homes.

  However, in wireless data communication using infrared rays, there is a problem that communication is hindered by a shielding object present between the transmission device and the reception device. Further, since the signal power is small, there is a problem that data communication, that is, signal transmission / reception tends to become unstable.

As a communication method for solving the above-described problems related to infrared communication, a communication method using light from an illumination light source as a data transmission medium (hereinafter sometimes referred to as illumination light communication) is considered. As a light source for illumination, a compound semiconductor-based white light emitting diode (hereinafter sometimes referred to as a white LED (Light Emitting Diode)) is used.
The illumination using the white LED has excellent features such as long life, small size, and low power consumption, as compared with conventional illumination such as a fluorescent lamp. Non-Patent Document 1 and Patent Document 1 disclose an illumination light communication system that pays attention to such features of white LEDs.

"Experimental study of modulation method suitable for visible light communication" (IEICE Technical Report OCS2005-19 (2005-5), pp. 43-48) JP 2003-318836 A

In illumination light communication, it is required to satisfy both the characteristics required for communication and the characteristics required for illumination. High communication speed is required for communication, and low power consumption is required for illumination. Therefore, for example, a high response speed and high luminous efficiency are required for the light source.
As described above, white LEDs have superior characteristics as illumination when compared with illumination such as fluorescent lamps. However, white LEDs used for illumination light communication have a response speed when compared with, for example, a semiconductor laser. Is low. In particular, white LEDs that are used for illumination are mainly those that use phosphors, but white LEDs that use phosphors are faster than those that do not use phosphors. Is low. Therefore, in conventional illumination light communication using white LEDs, the transmission speed is not always sufficient.
Therefore, when considering both the luminous efficiency and the response speed, the present applicant devised that an organic electroluminescence element (hereinafter sometimes referred to as an organic EL element) is used as a light source for illumination light communication. Further examination was added to. The organic EL element has a pair of electrodes and a light emitting layer disposed between the pair of electrodes. As one electrode of the pair of electrodes, an electrode exhibiting optical transparency (hereinafter sometimes referred to as an optically transparent electrode) is used, and light is extracted from the optically transparent electrode. As such a light transmissive electrode, for example, a thin film made of a metal oxide such as indium tin oxide (ITO), and a mesh-like conductive material including a conductive substance arranged in an irregular mesh shape. The body is used. The organic EL element is usually provided on a light-transmitting substrate (hereinafter sometimes referred to as a light-transmitting substrate), but light emitted from the organic EL element at the interface between the light-transmitting electrode and the light-transmitting substrate. May be reflected. As a result, the light extraction efficiency of the organic EL element is lowered. Therefore, the light emission efficiency of the organic EL element is not necessarily sufficient from the viewpoint of illumination.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a novel illumination light communication system having a high transmission rate and high luminous efficiency, and a transmission device that can be suitably applied to this illumination light communication system.

を満たす、照明光通信システム用の送信装置。
〔２〕 前記第１電極の可視光領域の光の透過率が８０％以上、体積抵抗率が１Ω・ｃｍ以下、表面粗さが１００ｎｍ以下である、〔１〕に記載の送信装置。
〔３〕 前記照明用光源は、それぞれの発光面積が１０^−８ｃｍ^２から１０^−１ｃｍ^２である複数の前記有機エレクトロルミネッセンス素子を備える、〔１〕または〔２〕に記載の送信装置。
〔４〕 前記照明用光源が、前記変調光を出射する通信用の有機エレクトロルミネッセンス素子と、非変調光を出射する照明用の有機エレクトロルミネッセンス素子とを備える〔１〕から〔３〕のいずれかに記載の送信装置。
〔５〕 前記通信用の有機エレクトロルミネッセンス素子の前記発光層が、蛍光を発光する発光材料を用いて形成され、かつ前記照明用の有機エレクトロルミネッセンス素子の発光層が、リン光を発光する発光材料を用いて形成されてなる〔４〕に記載の送信装置。
〔６〕 前記第１電極が、光透過性の膜本体、および該膜本体中に配置され、導電性を有するワイヤ状導電体を含む、〔１〕から〔５〕のいずれかに記載の送信装置。
〔７〕 前記ワイヤ状導電体の径が２００ｎｍ以下である、〔６〕に記載の送信装置。
〔８〕 前記ワイヤ状導電体が前記膜本体中において網目構造を構成している、〔７〕に記載の送信装置。
〔９〕 前記膜本体が導電性を有する樹脂を含んでいる、〔６〕から〔８〕のいずれかに記載の送信装置。
〔１０〕 前記第１電極が塗布法により形成されてなる、〔１〕から〔９〕のいずれかに記載の送信装置。
〔１１〕 変調光を出射する照明用光源を備える〔１〕から〔１０〕のいずれかに記載の送信装置と、前記照明用光源から出射された前記変調光を受光して電気信号に変換し、該電気信号を復調して受信データを生成する受信装置とを具備する、照明光通信システム。 In order to solve the above-described problems, the present invention employs the following configuration.
[1] A transmission device including an illumination light source that emits modulated light modulated based on transmission data, wherein the illumination light source includes a substrate exhibiting optical transparency and an organic electrometer provided in contact with the substrate. The organic electroluminescence element is provided between the first electrode, the second electrode, the first electrode, and the second electrode that are light-transmitting and disposed in contact with the substrate. Where the refractive index of the first electrode is n1 and the refractive index of the substrate is n2, each of n1 and n2 is represented by the following formula (1):

The transmission apparatus for illumination light communication systems which satisfy | fills.
[2] The transmission device according to [1], wherein the first electrode has a light transmittance of 80% or more, a volume resistivity of 1 Ω · cm or less, and a surface roughness of 100 nm or less.
[3] The transmission device according to [1] or [2], wherein the illumination light source includes a plurality of the organic electroluminescence elements each having a light emission area of 10 ⁻⁸ cm ² to 10 ⁻¹ cm ² .
[4] Any one of [1] to [3], wherein the illumination light source includes an organic electroluminescence element for communication that emits the modulated light and an organic electroluminescence element for illumination that emits non-modulated light. The transmitting device according to 1.
[5] A light emitting material in which the light emitting layer of the organic electroluminescence element for communication is formed using a light emitting material that emits fluorescence, and the light emitting layer of the organic electroluminescence element for illumination emits phosphorescence [4] The transmitter according to [4].
[6] The transmission according to any one of [1] to [5], wherein the first electrode includes a light-transmitting film main body, and a wire-shaped conductor disposed in the film main body and having conductivity. apparatus.
[7] The transmission device according to [6], wherein the wire-like conductor has a diameter of 200 nm or less.
[8] The transmission device according to [7], wherein the wire-like conductor forms a network structure in the film main body.
[9] The transmission device according to any one of [6] to [8], wherein the film body includes a conductive resin.
[10] The transmission device according to any one of [1] to [9], wherein the first electrode is formed by a coating method.
[11] The transmitter according to any one of [1] to [10] including an illumination light source that emits modulated light; and the modulated light emitted from the illumination light source is received and converted into an electrical signal. An illumination light communication system comprising: a receiving device that demodulates the electrical signal and generates reception data.

  In the illumination light communication system of the present invention, by using an organic EL element characterized by high-speed response as an illumination light source, the transmission speed can be significantly increased as compared with the case of using a conventional white LED. it can. In addition, the organic EL element included in the illumination light source is provided so that the light transmissive first electrode is in contact with the light transmissive substrate, so that the light emitted from the organic EL element passes through the first electrode and the substrate. It is taken out. Since the first electrode and the substrate satisfy the optical condition represented by the above-described formula (1), reflection at the interface between the first electrode and the substrate can be effectively suppressed. Therefore, the light extraction efficiency of the organic EL element can be further improved, and as a result, an illumination light source with high light emission efficiency can be realized. As a result, it is possible to provide a novel illumination light communication system having a high transmission rate and high luminous efficiency, and a transmission device that can be suitably applied to the illumination light communication system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, each figure has shown only the shape of the component, the magnitude | size, and arrangement | positioning to such an extent that an invention can be understood. The present invention is not limited to the following description, and each component can be appropriately changed without departing from the gist of the present invention. In each drawing used for the following description, the same components are denoted by the same reference numerals, and redundant description may be omitted. Further, in a device including an organic EL element, there are members such as electrode lead wires. However, in the description of the present invention, description thereof is omitted because it is not required directly. For the convenience of explanation of the layer structure and the like, in the example shown below, the explanation is made with the figure in which the substrate is arranged below. However, the organic EL element of the present invention and the organic EL device equipped with the same are necessarily manufactured in this arrangement. Or use etc. are not made. In the following description, one of the substrate in the thickness direction may be referred to as “up” or “up”, and the other in the thickness direction may be referred to as “down” or “down”.

<Configuration example of illumination light communication system (1)>
With reference to FIG. 1, it demonstrates per structural example of the illumination light communication system of this invention. FIG. 1 is a block diagram schematically illustrating a configuration of an illumination communication system.

  As illustrated in FIG. 1, the illumination communication system 10 includes a transmission device 20 and a reception device 30. The transmission device 20 includes an illumination light source 22. The illumination light source 22 emits modulated light modulated based on transmission data to be transmitted. The modulated light means light that is controlled to blink or light whose amount is controlled, and analog modulation methods (AM, FM, etc.), digital modulation methods, pulse modulation methods, and spread spectrum methods are used as modulation methods. .

  The transmission device 20 includes an organic EL element 26, and further includes a control circuit 28 that is connected to the organic EL element 26 and controls the operation of the organic EL element 26. Hereinafter, a configuration including the organic EL element 26 and the control circuit 28 is referred to as a light emitting unit 24. The illustrated example is an example in which the illumination light source 22 includes one light emitting unit 24. The control circuit 28 and the organic EL element 26 are electrically connected.

  The organic EL element 26 generates and emits only illumination light or both illumination light and signal light. Specific configurations of the organic EL element 26 and the control circuit 28 will be described later.

  The receiving device 30 includes a light receiving unit 32 and a demodulation unit 34. The receiving device 30 receives the modulated light emitted from the illumination light source 22 and generates reception data.

  The light receiving unit 32 incorporates a photoelectric conversion device (not shown) and converts the received modulated light into an electrical signal. The demodulator 34 demodulates the original data (transmission data) from the electrical signal photoelectrically converted by the light receiver 32 to generate reception data.

  When the transmission device 20 transmits data, data to be transmitted, that is, transmission data is supplied to the control circuit 28. Upon receiving the transmission data, the control circuit 28 controls the operation of the organic EL element 26 based on the supplied data.

  Thus, the modulated light modulated in accordance with the transmission data is emitted from the organic EL element 26, that is, the light emitting unit 24. As described above, even if the organic EL element 26 is blinked at high speed or its light amount is changed at high speed, it is not visually sensed. Therefore, even when used for communication, the organic EL element 26 is substantially constant. Looks like it's glowing with light. Therefore, the modulated light emitted from the organic EL element 26 can be used as illumination light as it is without giving a sense of incongruity to a person.

<Configuration example of illumination light communication system (2)>
With reference to FIG. 2 and FIG. 3, another configuration example of the illumination light communication system of the present invention will be described.

  In order to perform transmission with a large capacity of about 1 Gbps or more, a large number of light emitting units 24 may be two-dimensionally arranged in the transmission device 20 and operated in parallel with each other. In order to realize such a parallel system using conventional LEDs, it is necessary to arrange a large number of LEDs two-dimensionally and to perform wiring connection with a divider, and the system must be large. It was.

  When an organic EL element is used instead of the white LED, the completed individual light emitting units 24 are not retrofitted on the wiring board but arranged, for example, on a TFT (Thin Film Transistor) substrate on which the control circuit 28 is formed. A plurality of organic EL elements 26 can be directly formed, and an integrated device in which the light emitting units 24 are two-dimensionally arranged can be manufactured on the substrate from the beginning. Therefore, a very compact transmitter 20 can be realized even if other elements such as a divider are added.

  2 and 3 are block diagrams schematically illustrating a configuration example of the illumination communication system of the present invention.

  As shown in FIG. 2, the illumination light communication system 10 has a plurality of sets of light emitting units 24 and light receiving units 32 each including an organic EL element 26 and a control circuit 28 based on the configuration already described with reference to FIG. Has a set. In the illumination light source 22 of the transmission device 20, the plurality of light emitting units 24 are two-dimensionally arranged. The control circuit 28 further includes a serial / parallel conversion circuit 29, and the reception device 30 further includes a lens 36 and a parallel / serial conversion circuit 38.

  In the transmitting device 20 and the receiving device 30 in the illustrated example, the serial / parallel conversion circuit 29 is incorporated in the control circuit 28. However, the serial / parallel conversion circuit 29 is provided outside the control circuit 28. You can also. In this case, the control circuit 28 may control each organic EL element 26 based on the parallel signal generated from the serial / parallel conversion circuit 29.

  The serial / parallel conversion circuit 29 of the transmission device 20 divides serial data, which is transmission data, into a plurality of parallel data, and supplies the divided parallel data to the individual organic EL elements 26. Under the control of the control circuit 28 including the operation of the serial / parallel conversion circuit 29 of the transmission device 20, each organic EL element 26 emits modulated light modulated based on the parallel data given thereto. The emitted modulated light is spatially separated by the lens 36, photoelectrically converted by the photoelectric conversion device of each corresponding light receiving unit 32, and the converted electronic signal is digitized by an A / D converter (not shown) and received. The data is converted into serial data by the parallel / serial conversion circuit 38 of the device 30. The demodulator 34 demodulates the serial data to generate and output received data.

  In this way, by driving the plurality of organic EL elements 26 in parallel, a large amount of data can be transmitted at high speed.

  In the transmission device 20 shown in FIG. 2, the control (including modulation control) of the organic EL element 26 may be performed using a driver IC as an external drive circuit. In the transmission device 20 shown in FIG. 2, the operation of a plurality of organic EL elements 26 is controlled by a single control circuit 28.

  As shown in FIG. 3, a plurality of control circuits 28 that individually control each of the plurality of organic EL elements 26 may be connected to correspond to each organic EL 26 element. In this case, the illumination light source 22 includes a plurality of sets of light emitting units 24 that are integrally formed with one organic EL element 26 and one control circuit 28. In addition, when each organic EL element 26 is grouped into an element group including a plurality of organic EL elements 26 as one structural unit, the plurality of organic EL elements 26 and the organic EL element 26 included in the same element group The group of light emitting units 24 including the control circuit 28 to be connected may be referred to as a sub light source 23. As described later, by controlling light emission for each sub light source 23, each organic EL element 26 can be driven for each element group. By driving the plurality of organic EL elements 26 included in one element group as a unit in this way, the light intensity (signal intensity) as the element group unit increases, so that, for example, when used in a noisy environment, Even when the amount of light of each organic EL element 26 is small, it is possible to accurately transmit a signal and to realize an illumination optical communication system with a low error bit rate.

  A so-called thin film transistor (TFT) can be used as an example of a component of the control circuit 28 that is integrally formed with the organic EL element 26. As the thin film transistor, a polysilicon transistor, an amorphous silicon transistor, an organic transistor using an organic semiconductor material, and the like are known. By forming the control circuit 28 composed of such thin film transistors and the organic EL element 26 integrally, the transmitter 20 can be further reduced in size.

  Next, an illumination light source 22 configured as a so-called active matrix type will be described as a configuration example of the transmission device 20 of the illumination light communication system 10 described above with reference to FIG.

  In the active matrix type, the light emitting units 24 integrally configured with the organic EL elements 26 and the control circuit 28 are arranged in a matrix, and drive control of each of the plurality of organic EL elements 26 is made in the vicinity of the organic EL elements 26. This is the type performed by the embedded control circuit 28.

  When the active matrix type illumination light source 22 is configured using the organic EL element 26, the driving method of the organic EL element is roughly divided into two types, a current program method and a voltage program method. The “current programming method” refers to a method of supplying data to the data line at a current level, and the “voltage programming method” refers to a method of supplying data to the data line at a voltage level.

  FIG. 4 is a schematic explanatory diagram of an illumination light communication system using the active matrix illumination light source of the present invention.

  The illumination light source 22 included in the transmission device 20 is a so-called active matrix device in which the organic EL element 26 is driven by the control circuit 28 including, for example, a TFT, as described above.

  In this illumination light source 22, m × n (symbols “m” and “n” represent natural numbers respectively) light emitting units 24 are arranged in a matrix of m rows and n columns on a plane. That is, each light emitting unit 24 is arranged on the intersection of the lattice stripes.

  The illumination light source 22 has scanning line groups Y1 to Yn each consisting of n scanning lines Y extending in the row direction in FIG. 4 and spaced from each other in the column direction.

  In addition, the illumination light source 22 includes data line groups X1 to Xm including m data lines X that extend in the column direction and are spaced from each other in the row direction. The scanning line groups Y1 to Yn and the data line groups X1 to Xm form lattice fringes when viewed from one side in the thickness direction of the substrate.

  When viewed from one side in the thickness direction of the substrate, a pixel region 59 is provided in the vicinity of a plurality of intersections of the lattice stripes formed by the scanning lines Y and the data lines X, and one light emitting unit 24 is provided in each pixel region 59. Has been placed. In other words, the plurality of light emitting units 24 are arranged in a matrix for each pixel region 59.

  In FIG. 4, power supply lines for supplying predetermined voltages Vdd and Vss to the respective organic EL elements 26 are omitted.

  A preferred configuration example of the control circuit 28 provided in the light emitting unit 24 will be described with reference to FIGS.

  FIG. 5 is a circuit diagram showing the control circuit 28 provided in the light emitting unit 24 in the current program system. FIG. 6 is a circuit diagram showing the control circuit 28 provided in the light emitting unit 24 in the voltage program system.

  As shown in FIGS. 5 and 6, the light emitting unit 24 includes an organic EL element 26 and a control circuit 28 that is a circuit portion excluding the organic EL element 26.

<Current programming method>
As shown in FIG. 5, the control circuit 28 includes four transistors T1, T2, T3 and T4, a capacitor C which is data holding means for holding transmission data, a power supply voltage (supply means) Vdd, and a reference voltage (supply means). Vss as well as signal lines connecting them together are included.

  FIG. 5 shows an example in which the transistors T1, T2, and T4 are n-channel transistors and the transistor T3 is a p-channel transistor.

  The gate electrode of the transistor T1 is electrically connected to a predetermined scanning line Y to which the scanning signal SEL is supplied. The source electrode of the transistor T1 is electrically connected to a predetermined data line X to which the data current Idata is supplied. The drain electrode of the transistor T1 is electrically connected to the source electrode of the transistor T2.

  The drain electrode of the transistor T1 and the source electrode of the transistor T2 are electrically connected in common to the drain electrode of the transistor T3, which is a programming transistor, and the drain electrode of the transistor T4.

  Similarly to the gate electrode of the transistor T1, the gate electrode of the transistor T2 is electrically connected in common to the scanning line Y to which the scanning signal SEL is supplied. The drain electrode of the transistor T2 is electrically connected in common to one electrode of the capacitor C and the gate electrode of the transistor T3.

  A power supply voltage Vdd is applied to the other electrode of the capacitor C. The power supply voltage Vdd is applied to the source electrode of the transistor T3. A power supply voltage Vdd is applied to the other electrode of the capacitor C and the source electrode of the transistor T3.

  The drive signal GP is input to the gate electrode of the transistor T4. The anode (anode) of the organic EL element 26 is electrically connected to the drain electrode of the transistor T4. A reference voltage Vss that is lower than the power supply voltage Vdd is applied to the cathode (cathode) of the organic EL element 26.

<Voltage programming method>
Regarding the voltage programming method, the overall configuration of the transmission apparatus is as described above. However, in this case, since the data voltage (signal) Vdata is output to the data line X as it is, the variable current source of the data line driving circuit 44 (FIG. 4) electrically connected to the data line X becomes unnecessary. Become. Here, a configuration example called a so-called CC (Conductance Control) method will be described.

  As shown in FIG. 6, the light emitting unit 24 includes an organic EL element 26, transistors T1, T4 and T5, a capacitor C as data holding means, a power supply voltage (supply means) Vdd, a reference voltage (supply means) Vss, and these. Signal lines connected to each other are included. FIG. 6 shows an example in which all of the transistors T1, T4 and T5 are n-channel type.

  The gate electrode of the transistor T1, which is a so-called switching transistor, is electrically connected to a predetermined scanning line Y that supplies the scanning signal SEL. The drain electrode of the transistor T1 is electrically connected to a predetermined data line X that supplies a data voltage (signal) Vdata. The source electrode of the transistor T1 is electrically connected to one electrode of the capacitor C which is data holding means.

  The source electrode of the transistor T1 and one electrode of the capacitor C are electrically connected in common to the gate electrode of the transistor T4 that is a so-called driving transistor.

  A reference potential Vss is applied to the other electrode of the capacitor C. The power supply voltage Vdd is applied to the drain electrode of the transistor T4. The source electrode of the transistor T4 is electrically connected to the drain electrode of the transistor T5, which is a so-called control transistor.

  The drive signal GP is input to the transistor T5. The conduction of the transistor T5 is controlled by the drive signal GP. The source electrode of the transistor T5 is electrically connected to the anode of the organic EL element 26. A reference voltage Vss is applied to the cathode of the organic EL element 26.

  In the configuration example described above, an example in which a capacitor is used as a circuit element that holds data, that is, a preferred example of data holding means has been described. However, a memory device (SRAM or the like) that can store multi-bit data instead of the capacitor. Can also be used.

  The operation of the light emitting unit 24 described with reference to FIGS. 5 and 6 will be described with reference to FIG. FIG. 7 is an operation timing chart of the light emitting unit 24.

  Here, the timing at which selection of a predetermined light emitting unit 24 is started by the line sequential scanning from the scanning line Y1 to the scanning line Yn by the scanning line driving circuit 42 (FIG. 4) is assumed to be t0. The timing when the selection of the light emitting unit 24 is started next is t2. The period t0 to t2 is divided into a first programming period t0 to t1 and a second driving period t1 to t2.

<Operation in current programming method (circuit configuration shown in FIG. 5)>
In the first programming period t0 to t1, transmission data is written to the capacitor C. First, the scanning signal SEL is input to the scanning line Y at timing t0. As a result, the scanning line Y rises to a high level (hereinafter sometimes referred to as H level). Transistors T1 and T2 functioning as switching elements are both turned on (conductive). Then, the data line X and the drain electrode of the transistor T3 are electrically connected. As a result, the transistor T3 has a diode connection in which its own gate electrode and its own drain electrode are electrically connected.

  The transistor T3 allows the data current Idata supplied from the data line X to flow through its own channel. As a result, a voltage corresponding to the data current Idata is generated as the gate voltage Vg. Charges corresponding to the generated gate voltage Vg are accumulated in the capacitor C connected to the gate electrode of the transistor T3. As a result, data (transmission data) corresponding to the accumulated charge amount is written into the capacitor C.

  In the programming period t0 to t1, the transistor T3 functions as a programming transistor for writing data to the capacitor C based on a data signal flowing through its own channel. Further, during this period, the drive signal GP is maintained at a low level (hereinafter sometimes referred to as L level), so that the transistor T4 remains off (non-conducting). Therefore, the path of the drive current for the organic EL element 26 is blocked by the transistor T4. Therefore, the organic EL element 26 does not emit light.

In the subsequent driving period t1 to t2, the driving current flows through the organic EL element 26, and the luminance of the organic EL element 26 is set. First, at timing t1, the scanning signal SEL falls to the L level, and both the transistors T1 and T2 are turned off. As a result, the data line X to which the data current Idata is supplied and the drain electrode of the transistor T3 are electrically isolated, and the gate electrode and the drain electrode of the transistor T3 are also electrically isolated.
The gate voltage Vg corresponding to the accumulated charge of the capacitor C is continuously applied to the gate electrode of the transistor T3. In synchronization with the fall of the scanning signal SEL at the timing t1 (not necessarily at the same timing), the drive signal GP that was at the L level before that rises to the H level.

  As a result, a drive current path is formed from the power supply voltage Vdd to the reference voltage Vss, which is connected to the transistors T3 and T4 and the organic EL element 26. The drive current flowing through the organic EL element 26 corresponds to the channel current of the transistor T3, and the current level is controlled by the gate voltage Vg based on the accumulated charge in the capacitor C.

  In the driving period t1 to t2, the transistor T3 functions as a driving transistor that supplies a driving current to the organic EL element 26. As a result, the organic EL element 26 emits light with the light emission intensity modulated based on the data held in the capacitor C, in other words, according to the drive current.

<Operation in Voltage Program Method (Circuit Configuration shown in FIG. 6)>
First, the scanning line signal SEL is input to the predetermined scanning line Y at the timing t0. Then, the scanning line Y rises to H level and the transistor T1 is turned on. Therefore, the data voltage Vdata supplied to the data line X is applied to one electrode of the capacitor C through the transistor T1.

  As a result, a charge corresponding to the data voltage Vdata is accumulated in the capacitor C (transmission data is written). In the period from timing t0 to timing t1, the driving signal GP is maintained at the L level. Therefore, the control transistor T5 remains off. Accordingly, the current path of the drive current with respect to the organic EL element 26 is cut off, so that the organic EL element 26 does not emit light in the first half period t0 to t1.

  In the second half period t1 to t2 following the first half period t0 to t1, the drive current corresponding to the electric charge accumulated in the capacitor C flows through the organic EL element 26. Thereby, the organic EL element 26 emits light. At timing t1, the scanning signal SEL falls to the L level.

  Thereby, the transistor T1 is turned off. Therefore, the application of the data voltage Vdata to one electrode of the capacitor C is stopped, but the gate voltage Vg equivalent is applied to the gate electrode of the transistor T4 by the accumulated charge of the capacitor C. In synchronism with the fall of the scanning signal SEL at the timing t1, the drive signal GP, which was previously at the L level, rises to the H level.

  Thereby, the H level is maintained until the timing t2 when the selection of the light emitting unit 24 is started. Thus, a current path for the drive current is formed. Thereby, the organic EL element 26 emits light with a light emission intensity modulated based on the data held in the capacitor C.

  As already described with reference to FIG. 4, the drive circuit for driving the illumination light source 22 includes the scanning line drive circuit 42 and the data line drive circuit 44, both of which are not shown. Operate in cooperation with each other under synchronous control.

  The scanning line driving circuit 42 is mainly composed of a shift register, an output circuit, etc., and outputs scanning signals SEL to the scanning lines Y1 to Yn, thereby selecting the scanning lines Y1 to Yn in order in a predetermined selection order. Line sequential scanning is performed. The scanning signal SEL has a binary signal level of H level or L level, and the scanning line corresponding to a row (a plurality of light emitting units 24 connected to one line of the scanning line Y) to which data is written. Y is set to the H level, and each of the other scanning lines Y is set to the L level.

  Then, in one vertical scanning period (1F), each row is sequentially selected in a predetermined selection order. In addition to the scanning signal SEL, the scanning line driving circuit 42 also outputs a driving signal GP (or a base signal thereof) for controlling conduction of the transistor. The drive signal GP sets a drive period, that is, a period for setting the luminance of the organic EL element 26 included in the light emitting unit 24.

  The data line driving circuit 44 supplies data signals to the data lines X1 to Xm on a current basis in synchronization with the line sequential scanning by the scanning line driving circuit 42. In the case of the current programming method described above, the data line driving circuit 44 provides a variable current source that converts data (data voltage Vdata) that defines the modulation degree of the modulated light emitted from the light emitting unit 24 into the data current Idata. Including. In one horizontal scanning period (1H), the data line driving circuit 44 performs simultaneous output of the data current Idata for the row in which the current data is written and dot-sequential latching of data relating to the row in which writing is performed in the next horizontal scanning period. Do it at the same time.

  In a certain horizontal scanning period, m pieces of data corresponding to the number of data lines X are sequentially latched. Then, in the next horizontal scanning period, the latched m pieces of data are converted to the data current Idata and then output to the respective data lines X1 to Xm all at once.

  The configuration of the sub light source 23 will be described with reference to FIG. FIG. 8 is a schematic explanatory diagram of an illumination light communication system for explaining a configuration example of a sub light source.

  The sub light source 23 of the transmission device 20 is defined by dividing a plurality of light emitting units 24 included in the illumination light source 22 into a plurality of groups. In the illustrated example, a plurality of light emitting units 24 are divided into four, and a first sub-light source 23A, a second sub-light source 23B, a third sub-light source 23C, and a fourth sub-light source 23D (hereinafter referred to as sub-light source A and sub-light source, respectively). B, sub-light source C, and sub-light source D). Note that i and j are arbitrary positive numbers of 1 or more, and m and n are arbitrary positive numbers of 2 or more. The number of light emitting units 24 included in the first sub light source 23A, the second sub light source 23B, the third sub light source 23C, and the fourth sub light source 24D may be the same or different from each other. Further, when the number of the light emitting units 24 between the sub light sources 23 is the same, the arrangement of the light emitting units 24 may be the same or different for each sub light source 23 unit. In addition, the light emitting units 24 that are discretely arranged may be grouped into light emitting units 24 belonging to the same light emitting unit 24. By performing such grouping, even in units of sub-light sources 23, it is possible to perform grouping. Even if blinking or the like is performed, a local decrease in the amount of light can be suppressed, and a decrease in performance as illumination can be suppressed.

  Here, the number of light emitting units 24 included in the first sub light source 23A, the second sub light source 23B, the third sub light source 23C, and the fourth sub light source 24D is i = j = 4 and m = n = 8, that is, the same number. An example of 16 will be described. The light emitting units 24 included in each of the first sub light source 23A, the second sub light source 23B, the third sub light source 23C, and the fourth sub light source 23D are arranged in a 4 × 4 matrix in this example.

  The light emitting units 24 of the first sub-light source 23A and the second sub-light source 23B are electrically connected to the scanning lines Y1 to Yj (Y4) (sometimes referred to as a scanning line group Yab). The light emitting units 24 of the third sub light source 23C and the fourth sub light source 23D are electrically connected to the scanning lines Yj + 1 to Yn (Y5 to Y8) (sometimes referred to as a scanning line group Ycd).

  The light emitting units 24 of the first sub light source 23A and the third sub light source 23C are electrically connected to data lines X1 to Xi (X4) (sometimes referred to as data line group Xac). The light emitting units 24 of the second sub light source 23B and the fourth sub light source 23D are electrically connected to data lines Xi + 1 to Xm (X5 to X8) (sometimes referred to as data line group Xbd).

  Next, with reference to FIG. 4, FIG. 8, and FIG. 9, the operation of the illumination light communication system including illumination light sources grouped into a plurality of sub-light sources will be described.

  The scanning line driving circuit 42 and the data line driving circuit 44 (FIG. 4) are provided in the first sub-light source 23A, the second sub-light source 23B, the third sub-light source 23C, and the fourth sub-light source 23D set as the illumination light source 22, respectively. A plurality of sub light sources 23 are independently driven in units of each sub light source 23.

  In the present embodiment, the plurality of light emitting units 24 belonging to the same sub light source 23 are all controlled to be in the same light emitting state. Different sub-light sources 23 can be controlled independently of each other. Therefore, in this case, four independent transmission channels are formed in the illumination light source 22.

  Data (all at the same current level) supplied to the data lines X1 to Xi, that is, the data line group Xac in a state where the scanning lines Y1 to Yj, that is, the scanning line group Yab are selected, are the first sub-light source 23A. Are commonly supplied to the light emitting units 24.

  Thereby, the light emission state of the first sub-light source 23A is controlled. In this state, the data supplied to the data lines Xi + 1 to Xm, that is, the data line group Xbd, is supplied in common to the light emitting units 24 of the second sub light source 23B. Thereby, the light emission state of the second sub-light source 23B is controlled.

  Data supplied to the data lines X1 to Xi, that is, the data line group Xac in a state where the scanning lines Yj + 1 to Yn, that is, the scanning line group Ycd are selected, is common to each light emitting unit 24 of the third sub-light source 23C. To be supplied.

  Thereby, the light emission state of the third sub-light source 23C is controlled. In this state, the data supplied to the data lines Xi + 1 to Xm, that is, the data line group Xbd, is supplied in common to the light emitting units 24 of the fourth sub light source 23D. Thereby, the light emission state of the fourth sub-light source 23D is controlled.

  FIG. 9 is a timing chart for explaining the operation of the illumination light communication system.

  In the configuration shown in FIG. 8, n scanning lines Y are sequentially selected from the scanning line Y1 arranged at the uppermost stage toward the scanning line Yn arranged at the lowermost stage.

  In this case, one frame period t0 to t2 required for writing the transmission data to the entire illumination light source 22 is the selection period t0 to the first sub-light source 23A and the second sub-light source 23B in the first half. It is divided into t1 and selection periods t1 to t2 of the third sub-light source 23C and the fourth sub-light source 23D in the latter half.

  The selection periods t0 to t1 of the first sub-light source 23A and the second sub-light source 23B correspond to the period from the start of the selection of the scanning line Y1 belonging to the scanning line group Yab to the end of the selection of the scanning line Yj.

  During this period t0 to t1, the transmission data Da for the first sub-light source 23A is commonly supplied to the data line group Xac, and the data line group Xac is maintained at a level corresponding to the transmission data Da.

  Not only the first sub-light source 23A but also the third sub-light source 23C is connected to the data line group Xac, but the third sub-light source 23C is electrically separated because the scanning line group Ycd is not selected. . Therefore, the transmission data Da supplied to the data line group Xac is supplied only to the first sub-light source 23A, and writing corresponding to this is performed in the first sub-light source 23A.

  In this period t0 to t1, the transmission data Db for the second sub light source 23B is commonly supplied to the data line group Xbd, and the data line group Xbd is maintained at a level corresponding to the transmission data Db.

  Although not only the second sub light source 23B but also the fourth sub light source 23D is connected to the data line group Xbd, the fourth sub light source 23D is electrically separated because the scanning line group Ycd is not selected. . Therefore, the transmission data Db supplied to the data line group Xbd is supplied only to the second sub light source 23B, and writing corresponding to this is performed in the second sub light source 23B.

  The selection periods t1 to t2 of the third sub light source 23C and the fourth sub light source 23D correspond to the period from the start of the selection of the scanning line Yj + 1 belonging to the scanning line group Ycd to the end of the selection of the scanning line Yn. To do. During this period t1 to t2, the transmission data Dc for the third sub-light source 23C is commonly supplied to the data line group Xac, and the data line group Xac is maintained at a level corresponding to the transmission data Dc.

  Here, the first sub-light source 23A connected to the data line group Xac is electrically separated because the scanning line group Yab is not selected. Accordingly, the transmission data Dc supplied to the data line group Xac is supplied only to the third sub-light source 23C, and writing according to this is performed in the third sub-light source 23C.

  In the period t1 to t2, the transmission data Dd for the fourth sub light source 23D is commonly supplied to the data line group Xbd, and the data line group Xbd is maintained at a level corresponding to the transmission data Dd. At this time, the second sub light source 23B connected to the data line group Xbd is electrically separated because the scanning line group Yab is not selected. Therefore, the transmission data Dd supplied to the data line group Xbd is supplied only to the fourth sub-light source 23D, and writing according to this is performed in the fourth sub-light source 23D.

  In FIG. 9, the scanning line group corresponding to the same sub light source 23 is sequentially scanned. However, the scanning corresponding to each sub light source 23 is provided on the condition that the drive circuit can have sufficient driving capability. Line groups can be selected simultaneously.

  Here, if the control circuit 28 is configured as shown in FIG. 5 and FIG. 6, the first sub-light source 23A, the second sub-light source 23B, the third sub-light source 23B, the third sub-light source 23B, the third sub-light source 23B. Independent drive of the sub-light source 23C and the fourth sub-light source 23D can be realized.

<Organic EL device>
The organic EL element has excellent features such as free size design, miniaturization, and high-speed response. When the organic EL element is used for illumination light communication, it is preferable that each element area is smaller. Since the capacitance of the organic EL element tends to be smaller as the area of each element is smaller, the RC time constant of the element that defines the response speed is similarly reduced. As a result, the smaller the area of the organic EL element is, the smaller the area is. This is because the response speed increases.

Element area (light emission area) is preferably well to the 10 ^-8 cm ² or more 1 cm ² or less, more preferably better to the 10 ^-8 cm ² or more 10 ^-1 cm ² or less, more preferably 10 ^It should be ^-8 cm ² or more and 10 ^-2 cm ² or less.

  In a conventional LED, after an LED is formed on a semiconductor substrate, the semiconductor substrate is divided into individual chips, and the chip is attached to a circuit board on which wiring is formed. Since the chip is provided with a connection portion necessary for connecting the LED to the circuit board, the size of the chip is larger than that of the LED. Moreover, since a base, a resin lens, etc. are needed as a chip | tip of LED, it becomes an element larger than the part which actually light-emits. Furthermore, in order to mount the chip on the circuit board, it is necessary to provide a connection site on the board side, so a larger mounting area than the chip is required, and even if the LED itself is small, There is a limit to downsizing.

  On the other hand, in the case of an organic EL element, for example, the element can be formed directly and integrally with the wiring on the substrate on which the control circuit for controlling the operation of the element and the wiring are formed. That is, unlike the conventional LED, a mounting area larger than the size of the organic EL element itself is not required, the light emitting unit can be easily highly integrated, and the transmission device can be downsized. And since the organic EL element built in the board | substrate can be operated and used as it is, the freedom degree in design is high and size reduction of an element is comparatively easy. For the reasons described above, the organic EL element is extremely suitable as a light emitting element for illumination light communication.

  In order to enable high-speed communication of large-capacity data, it is preferable to transmit data from a plurality of light emitting units in parallel. For this purpose, it is necessary to arrange a plurality of light emitting units.

  In the conventional LED, since it is necessary to arrange individual LED chips or elements composed of a pedestal and a resin lens on the chip, an area larger than a portion that actually emits light is required.

  On the other hand, in the organic EL element, since the element can be directly formed on the substrate on which the wiring and the control circuit are formed and the element is operated as it is, it is easy to highly integrate the light emitting unit. A small communication light source (transmission device) can be realized.

  In the case of a conventional LED, the intensity modulation of the illumination light source in the transmission device has to be performed using an external control circuit such as a driver IC (IC: Integrated Circuit). For this reason, it is difficult to reduce the size of the units constituting the transmission apparatus.

  On the other hand, in the case of an organic EL element, a control circuit composed of a modulation element such as a thin film transistor can be integrally formed in the vicinity of the light emitting portion including the light emitting layer. If the control circuit and the organic EL element are laminated and integrated, for example, the light emitting unit can be easily downsized.

  Thus, by using the organic EL element, the light emitting unit can be further miniaturized and integrated, and a laminated structure of the organic EL element and the control circuit can be easily manufactured. Downsizing of the transmission device corresponding to the above can be realized.

  As the organic EL element, a fluorescence emission type (singlet transition) and a phosphorescence emission type (triplet transition) are known, but either one may be used in this embodiment. Even if the organic EL element is made small and the RC time constant is reduced to increase the response speed, the response speed cannot be increased beyond the speed defined by the decay time of light emission.

  Organic EL elements are classified into fluorescent emission (emission from a singlet excited state) type and phosphorescent emission (emission from a triplet excited state) type depending on the mechanism of emission. In general, the fluorescence emission type has a shorter emission decay time than the phosphorescence emission type, and is about 10 ns for the fluorescence emission type and about 1 μs for the phosphorescence emission type at room temperature (about 20 ° C.). Therefore, whichever one is used, signal communication up to a transmission rate of about 1 Mbps can be accommodated with a single element.

  In the embodiment of the present invention, an integrated device in which both a fluorescent light emitting organic EL element and a phosphorescent organic EL element are mounted together may be used as an illumination light source. Since the fluorescence emission type can make the response speed faster than the phosphorescence emission type, it can be said that it is suitable for high-speed communication applications. The phosphorescent light emitting type can be made higher in luminous efficiency than the fluorescent light emitting type, and thus is suitable for lighting applications.

  The organic EL element can be formed by selectively dividing the light emitting layer material for each element. Therefore, in the illumination light source, for example, the illumination light source is modulated based on the transmission data such that the illumination organic EL element is a phosphorescent emission type and the communication organic EL element is a fluorescence emission type. A communication organic EL element that emits modulated light and an organic EL element for illumination that emits non-modulated light may be included.

  In this case, the fluorescent organic EL element has both an illumination function and a communication function, and is used as a communication organic EL element that emits modulated light modulated based on transmission data to be transmitted. It is good to use this. In addition, the phosphorescent organic EL element is preferably used as an organic EL element for illumination that emits a certain amount of non-modulated light while having only an illumination function.

  The organic EL element for illumination and the organic EL element for communication may have a configuration in which any organic EL element is selected and provided for each sub-light source described above. Further, an organic EL element for illumination and an organic EL element for communication may be mixed in a single sub-light source.

  Thereby, it is possible to construct an illumination system that achieves both improved illumination efficiency and higher communication speed. However, in such a configuration, the ratio of light on which communication information is superimposed, that is, signal light, is small with respect to the total amount of light from the illumination. Therefore, a system sensitive to a change in light intensity is required as a receiving device. The ratio of fluorescence, ie, signal light, to the total amount of light is preferably 1% or more and 50% or less.

  When performing illumination light communication using general illumination, the illumination light source is preferably white. In order to obtain white light with an organic EL element, there are roughly the following two methods.

  One is a method of obtaining white light by superimposing light emitted from a plurality of light sources. In this method, (1) an organic EL element that emits red light (R element), an organic EL element that emits green light (G element), and an organic EL element that emits blue light (B element) are disposed within the substrate surface. And (2) a method of laminating elements having light emitting layers that emit light at different emission wavelengths in a multiphoton organic EL element, and (3) The organic EL element which is not a multi-photon type is divided into a method of laminating a plurality of light emitting layers that emit light at different light emission wavelengths.

  The other is a method of obtaining white light emission by using a light emitting layer that emits light with a white spectrum.

These organic EL devices that emit white light are obtained by direct recombination of current injection using a conventional phosphor, such as blue light emission by phosphor injection → phosphor excitation → yellow light emission, without using a process such as white LED. White light is emitted. Therefore, there is a feature that the response speed is faster than a white LED using a conventional phosphor, which is suitable for an illumination light communication system.
<Configuration example 1>

  With reference to FIG. 10, a configuration example (configuration example 1) of the organic EL element 26 that can be suitably applied to the transmission device will be described.

  FIG. 10 is a schematic cross-sectional view of an organic EL element. The organic EL element 26 of Configuration Example 1 is provided on the substrate 51. Here, the configuration of one organic EL element 26 formed on the substrate 51 as a so-called active matrix light source will be described.

On the substrate 51, a plurality of pixel regions 59 are set in a matrix. Each pixel region 59 is partitioned by a partition wall 60. The partition wall 60 is provided in a lattice shape, and each organic EL element 26 is disposed in each pixel region 51 electrically separated by the partition wall 60. The partition wall 60 separates the stacked structure of the first electrode 52 and the light emitting layer 56 for each organic EL element 26.
The partition wall 60 is formed by, for example, spin-coating a photosensitive resist solution on a region that defines a pixel region 59 on the substrate 51 on which the first electrode 52 described later is formed, and exposing and developing the photosensitive resin solution. A partition wall 60 can be formed.

  In the present specification, “light” means an electromagnetic wave having a wavelength in the range of about 1 nm to 1 mm. “Light transmissive” means that light having a wavelength included in the range selected from the above “light” can be used as illumination light and signal light without being absorbed and scattered, or incident. The transmitted illumination light and signal light are transmitted at an acceptable ratio. The illumination light and the signal light are preferably “visible light”. “Visible light” refers to electromagnetic waves having a wavelength in a range that can be detected by the human eye. Visible light generally has a wavelength of about 360 to 400 nm on the short wavelength side and a wavelength of about 760 to 830 nm on the long wavelength side. In this embodiment, if the visible light transmittance is about 25% or more, the light transmittance is assumed.

  On the pixel region 59 set on the substrate 51, the organic EL element 26 is provided. The organic EL element 26 is provided between the light emitting layer 56, the first functional layer 53 provided as needed between the anode 52 and the light emitting layer 56, and between the light emitting layer 56 and the cathode 58 as needed. And a second functional layer 57. On the substrate 51, a light transmissive first electrode 52 (hereinafter sometimes referred to as an anode 52), which is an anode in this example, is disposed.

  On the anode 52, a light emitting layer 56 is disposed with a first functional layer 53 interposed therebetween as desired. On the light emitting portion 56, a second electrode 58 (which may be referred to as a cathode 58) serving as a cathode is disposed across a plurality of pixel regions 59 in this example with the second functional layer 57 interposed therebetween as desired. A protective layer (sometimes referred to as an upper sealing film) 70 is provided to protect the cathode 58.

  In the present embodiment, the light transmissive first electrode 52 is an anode and the second electrode 58 is a cathode, but the first electrode 52 is a cathode and the second electrode 58 is a cathode in the order of stacking. You may comprise the organic EL element 26 which is an anode.

(substrate)
The substrate 51 has a high light transmittance in the visible light region and does not change in the process of forming the organic EL element. The substrate 51 may be a rigid substrate or a flexible substrate. For example, a glass plate, a plastic plate, A molecular film, a silicon plate, and a laminated plate obtained by laminating these are preferably used. The substrate 51 may be a so-called TFT substrate including a configuration such as the above-described control circuit (28) including a thin film transistor, a capacitor, a wiring layer, and the like (not shown) within its thickness.

  As the substrate 51, a substrate 51 having a refractive index that has a refractive index difference of less than 0.3 with respect to the light transmissive first electrode 52 is appropriately used.

(First electrode)
The first electrode 52 includes a light-transmitting film body and a wire conductor (not shown) disposed in the film body and having conductivity. As the light-transmitting film body, one having a particularly high light transmittance in the visible light region is preferably used. The film body includes a resin, an inorganic polymer, an inorganic-organic hybrid compound, and the like.

  As the light-transmitting film body, a resin having conductivity among the resins is preferably used. Thus, in addition to the wire-like conductor, by using a conductive film body, the first electrode 52 can be further reduced in electrical resistance (hereinafter, the electrical resistance may be referred to as resistance). By using the first electrode 52 having such a low resistance, a voltage drop at the first electrode 52 can be suppressed, low voltage driving of the organic EL element 26 can be realized, and luminance unevenness can be suppressed.

  The film thickness of the first electrode 52 is appropriately set depending on the electrical resistance and the transmittance of visible light, and is, for example, 0.03 μm to 10 μm, and preferably 0.05 μm to 1 μm.

  The wire-like conductor preferably has a small diameter, for example, a diameter of 400 nm or less is used, preferably a diameter of 200 nm or less, and more preferably a diameter of 100 nm or less. The wire-like conductor disposed in the film body diffracts or scatters the emitted light from the organic EL element 26 that passes through the first electrode 52, so that the haze value of the first electrode 52 is increased and the transmittance of the emitted light is increased. Although using a wire-like conductor having a diameter that is about the wavelength of visible light or smaller than the wavelength of visible light, the haze value for emitted light, that is, visible light can be kept low and the transmittance can be improved. it can. Moreover, since resistance will become large if the diameter of a wire-like conductor is too small, a thing with a diameter of 10 nm or more is preferable. In addition, since the organic EL element of the present invention is used in a lighting device, if the haze value of the first electrode 52 is somewhat large, it is possible to provide a function of diffusing emitted light. A thing with a large haze value may be used suitably.

  One or a plurality of wire-like conductors arranged in the film main body may be used, and it is preferable that a network structure is formed in the film main body. For example, in the membrane main body, one or a plurality of wire-like conductors are arranged in an intricately intertwined manner over the entire membrane main body to form a network structure. Specifically, a structure in which one wire-like conductor is intertwined in a complicated manner or a plurality of wire-like conductors are arranged in contact with each other spreads two-dimensionally or three-dimensionally to form a network structure. Forming. By forming the wire-like conductor as having a network structure, the volume resistivity of the first electrode 52 can be lowered.

  The wire-like conductor is preferably arranged so that at least a part of the wire-like conductor is exposed near the surface of the first electrode 52 opposite to the substrate 51. By arranging the wire-like conductor in this way, the resistance of the surface portion of the first electrode 52 can be lowered.

  The shape of the wire-like conductor may be, for example, a curved shape or a needle shape. The curved and / or needle-shaped conductors contact each other in the film body to form a network structure, whereby the first electrode 52 having a low volume resistivity can be realized.

(Wire conductor material)
As a material for the wire-like conductor, for example, a low resistance metal such as Ag, Au, Cu, Al, and alloys thereof is preferably used. For example, the wire conductor is a method by NRJana, L. Gearheart and CJMurphy (Chm. Commun., 2001, p617-p618), a method by C. Ducamp-Sanguesa, R. Herrera-Urbina, and M. Figlarz ( J. Solid State Chem., Vol. 100, 1992, p272-p280).

(Formation method of the first electrode)
As a method of forming the first electrode 52, for example, the above-described wire-like conductor is kneaded into a resin to disperse the resin, and the resin is applied. The wire-like conductor and the resin are dispersed. Examples include a method of forming a film by a coating method using a dispersion liquid dispersed in a medium, and a method of coating a wire-like conductor on the surface of a film made of resin and dispersing the wire-like conductor in the film. it can.

  In addition, you may add various additives, such as surfactant and antioxidant, to the 1st electrode 52 as needed. The type of resin is appropriately selected according to the characteristics required for the first electrode 52, such as refractive index, light transmittance, and electrical resistance.

  In addition, the amount of the wire-like conductor dispersed affects the electrical resistance, haze value, translucency, and the like of the first electrode 52, and thus is appropriately set according to the characteristics of the first electrode 52.

  The first electrode 52 of the present embodiment is obtained by applying a dispersion liquid in which a conductive wire-like conductor is dispersed in a dispersion medium to the surface of the substrate 51 and further curing the coating film.

  The dispersion is prepared by dispersing a wire-like conductor and a resin in a dispersion medium. The dispersion medium may be any material that can dissolve the resin, for example, a chlorine-based solvent such as chloroform, methylene chloride or dichloroethane, an ether-based solvent such as tetrahydrofuran, an aromatic hydrocarbon-based solvent such as toluene or xylene, acetone, or methyl ethyl ketone. And ketone solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate.

  In addition, as the resin, a resin having high transmissivity is preferable. When the layer provided on the first electrode 52 is formed by a coating method, the resin constituting a part of the first electrode 52 is used as the coating liquid. It must be insoluble. Examples of such resins include low density or high density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, and ethylene-norbornene copolymer. Polyolefin resins such as ethylene-dmon copolymer, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ionomer resin; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; Nylon-6, nylon-6,6, metaxylenediamine-adipic acid condensation polymer; amide resin such as polymethylmethacrylamide; acrylic resin such as polymethylmethacrylate; polystyrene, styrene-acrylic Styrene-acrylonitrile resins such as nitrile copolymers, styrene-acrylonitrile-butadiene copolymers, polyacrylonitrile; hydrophobic cellulose resins such as cellulose triacetate and cellulose diacetate; polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride Halogen-containing resins such as polytetrafluoroethylene; hydrogen-bonding resins such as polyvinyl alcohol, ethylene-vinyl alcohol copolymers and cellulose derivatives; polycarbonate resins, polysulfone resins, polyethersulfone resins, polyetheretherketone resins, polyphenylene Examples thereof include engineering plastic resins such as oxide resins, polymethylene oxide resins, polyarylate resins, and liquid crystal resins.

  Moreover, when forming the layer provided on the 1st electrode 52 by the apply | coating method, from the viewpoint that the resin which comprises a part of 1st electrode 52 is hard to melt | dissolve in a coating liquid, a thermosetting resin and a photocurable property are used. Resins and photoresist materials are preferably used.

  Among the exemplified resins, a resin having conductivity is preferably used, and examples of the resin having conductivity include polyaniline and polythiophene derivatives.

  The refractive index of the first electrode 52 is mainly determined by the refractive index of the film body made of resin or the like. The refractive index of the film body is mainly determined by, for example, the type of resin to be used. Therefore, the first electrode 52 having the intended refractive index can be easily formed by selecting the resin to be used.

  In addition, if a dispersion liquid in which a wire-like conductor is dispersed in a photosensitive material and a photocurable monomer used for a photosensitive photoresist, a predetermined pattern shape is obtained by a coating process by a coating method and a photolithography process. The first electrode 52 can be easily formed.

  The first electrode 52 is preferably one that does not deform at the temperature heated in the step of forming the organic EL element 26, and the resin constituting the first electrode 52 preferably has a glass transition point Tg of 150 ° C. or higher. More preferably, 180 ° C or higher, more preferably 200 ° C or higher. Examples of such a resin include polyether sulfone having a glass transition point Tg of 230 ° C. and a high heat resistant photoresist material.

  The dispersion amount of the wire-like conductor, and the binder and additive mixed in the dispersion liquid as necessary are appropriately set according to conditions such as the ease of film formation and the characteristics required for the first electrode 52. You can choose.

  The coating method of the dispersion liquid in which the wire-like conductor is dispersed includes dipping method, coating method by bar coater, coating method by spin coater, doctor blade method, spray coating method, screen mesh printing method, brush coating, spraying, roll coating, etc. The method usually used industrially can be mentioned. In addition, when using a thermosetting resin and a photocurable resin, after apply | coating a dispersion liquid, a coating film can be hardened by a heating or light irradiation.

(Light emitting layer)
The light emitting layer 56 is provided between the first electrode 52 and the second electrode 58. The light emitting layer 56 may be composed of a plurality of layers as long as it includes at least one light emitting layer. Between the anode (first electrode 52 in the present embodiment) and the light emitting layer 56, a first functional layer 53 including a predetermined layer or a plurality of layers is provided as necessary. In addition, a second functional layer 57 including a predetermined layer or a plurality of layers is provided between the light emitting layer 56 and the cathode (the second electrode 58 in the present embodiment) as necessary.

(First functional layer)
Examples of the first functional layer 53 provided between the anode (first electrode 52) and the light emitting layer 56 include a hole injection layer, a hole transport layer, and an electron block layer. In the case where the hole injection layer and / or the hole transport layer has a function of blocking electron transport, these layers may also serve as the electron blocking layer. The electron blocking layer is a layer having a function of blocking electron transport. The fact that the electron blocking layer has a function of blocking electron transport makes it possible, for example, to produce an element that allows only electron current to flow and confirm the blocking effect by reducing the current value.

(Second functional layer)
Examples of the second functional layer 57 provided between the light emitting layer 56 and the cathode (second electrode 58) include an electron injection layer, an electron transport layer, and a hole blocking layer. When both the electron injection layer and the electron transport layer are provided between the cathode 58 and the light emitting layer 56, the layer in contact with the cathode 58 is referred to as an electron injection layer, and the layers other than the electron injection layer are defined as electron injection layers. It is called a transport layer. In the case where the electron injection layer and / or the electron transport layer have a function of blocking hole transport, these layers may also serve as the hole blocking layer. The hole blocking layer is a layer having a function of blocking hole transport. The fact that the hole blocking layer has a function of blocking hole transport makes it possible, for example, to produce an element that allows only a hole current to flow, and confirm the blocking effect by reducing the current value.

In the organic EL element 26 of the present embodiment, a combination example of layer configurations from the anode 52A to the cathode 58 is shown below.
a) Anode / light emitting layer / cathode b) Anode / hole injection layer / light emitting layer / cathode c) Anode / hole injection layer / light emitting layer / electron injection layer / cathode d) Anode / hole injection layer / hole transport Layer / light emitting layer / cathode e) anode / hole injection layer / hole transport layer / light emitting layer / electron injection layer / cathode f) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron Injection layer / cathode g) Anode / light-emitting layer / electron injection layer / cathode h) Anode / light-emitting layer / electron transport layer / electron injection layer / cathode (Here, the symbol “/” indicates each layer sandwiching the symbol “/”) (Indicates that they are stacked adjacently. The same shall apply hereinafter.)

In addition, the organic EL element 26 of the present embodiment may have two or more light emitting layers 56, and the organic EL element having the two light emitting layers 56 has a layer configuration shown in i) below. Can be mentioned.
i) Anode / charge injection layer / hole transport layer / light emitting layer / electron transport layer / charge injection layer / charge generation layer / charge injection layer / hole transport layer / light emitting layer / electron transport layer / charge injection layer / cathode Specifically, as an organic EL device having three or more light emitting layers, (charge generation layer / charge injection layer / hole transport layer / light emission layer / electron transport layer / charge injection layer) is one repeating unit. Examples of the layer structure include two or more repeating units shown in j) below.
j) Anode / charge injection layer / hole transport layer / light emitting layer / electron transport layer / charge injection layer / (repeat unit) / (repeat unit) /... / cathode

  In the above layer configuration, each layer other than the anode, the cathode, and the light emitting layer can be left unformed as necessary.

  Here, the charge generation layer is a layer that generates holes and electrons by applying an electric field. Examples of the charge generation layer include a thin film made of vanadium oxide, indium tin oxide (abbreviated as ITO), molybdenum oxide, or the like.

  In the organic EL element 26, the anode 52A is normally disposed on the substrate 51 side as in the present embodiment, but the cathode 58 may be disposed on the substrate 51 side.

  In the organic EL element 26 of the present embodiment, an insulating layer having a thickness of 2 nm or less may be provided adjacent to the electrode in order to improve the adhesion to the electrode and the charge injection property from the electrode. In addition, a thin buffer layer may be inserted between each of the aforementioned layers in order to improve adhesion at the interface or prevent mixing.

Hereinafter, the configuration of each layer will be described in more detail.
(Hole injection layer)
The hole injection layer is a layer having a function of improving the hole injection efficiency from the anode (first electrode) 52A. As a material constituting the hole injection layer, a known material can be appropriately used, and there is no particular limitation. For example, phenylamine, starburst amine, phthalocyanine, hydrazone derivative, carbazole derivative, triazole derivative, imidazole derivative, oxadiazole derivative having amino group, vanadium oxide, tantalum oxide, tungsten oxide, molybdenum oxide, ruthenium oxide And oxides such as aluminum oxide, amorphous carbon, polyaniline, polythiophene derivatives, and the like.

  As a film formation method of the hole injection layer, for example, film formation from a solution containing a material (hole injection material) that becomes the hole injection layer can be mentioned. The solvent used for film formation from a solution is not particularly limited as long as it dissolves the hole injection material. Chlorine solvents such as chloroform, methylene chloride and dichloroethane, ether solvents such as tetrahydrofuran, toluene, Mention may be made of aromatic hydrocarbon solvents such as xylene, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate, and water.

  As a film forming method from a solution, a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a spray coating method, a screen printing method, Examples of the application method include a flexographic printing method, an offset printing method, and an ink jet printing method.

  The thickness of the hole injection layer is preferably about 5 nm to 300 nm. If the thickness is less than 5 nm, the production tends to be difficult. On the other hand, if the thickness exceeds 300 nm, the driving voltage and the voltage applied to the hole injection layer tend to increase.

(Hole transport layer)
The hole transport layer is a layer having a function of improving hole injection from the anode, the hole injection layer, or the hole transport layer closer to the anode. The material constituting the hole transport layer is not particularly limited. For example, N, N′-diphenyl-N, N′-di (3-methylphenyl) 4,4′-diaminobiphenyl (TPD), 4 , 4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPB) and other aromatic amine derivatives, polyvinylcarbazole or derivatives thereof, polysilane or derivatives thereof, aromatic amines in the side chain or main chain Polysiloxane derivative having pyrazole, pyrazoline derivative, arylamine derivative, stilbene derivative, triphenyldiamine derivative, polyaniline or derivative thereof, polythiophene or derivative thereof, polyarylamine or derivative thereof, polypyrrole or derivative thereof, poly (p-phenylene vinylene) Or its derivatives, or poly (2,5-thienylene vinylene) or a derivative thereof is exemplified.

  Among these, as the hole transport material used for the hole transport layer, polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine compound group in a side chain or a main chain, polyaniline or a derivative thereof, Polymeric hole transport materials such as polythiophene or derivatives thereof, polyarylamine or derivatives thereof, poly (p-phenylene vinylene) or derivatives thereof, or poly (2,5-thienylene vinylene) or derivatives thereof are preferred, and more preferred Is polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, and a polysiloxane derivative having an aromatic amine in the side chain or main chain. In the case of a low-molecular hole transport material, it is preferably used by being dispersed in a polymer binder.

  The method for forming the hole transport layer is not particularly limited, but in the case of a low molecular hole transport material, film formation from a mixed solution containing a polymer binder and a hole transport material can be exemplified. Examples of molecular hole transport materials include film formation from a solution containing a hole transport material.

The solvent used for film formation from a solution is not particularly limited as long as it dissolves the hole transport material, and is a chlorine-based solvent such as chloroform, methylene chloride, dichloroethane, an ether-based solvent such as tetrahydrofuran, toluene, Examples thereof include aromatic hydrocarbon solvents such as xylene, ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate, butyl acetate, and ethyl cellosolve acetate.
Examples of the film forming method from a solution include the same coating method as the above-described film forming method of the hole injection layer.

  As the polymer binder to be mixed, those that do not extremely inhibit charge transport are preferable, and those that weakly absorb visible light are preferably used. For example, polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, poly Examples thereof include vinyl chloride and polysiloxane.

  The thickness of the hole transport layer is not particularly limited, but can be appropriately changed according to the intended design, and is preferably about 1 to 1000 nm. If the thickness is less than the lower limit, production tends to be difficult, or the effect of hole transport is not sufficiently obtained. On the other hand, if the thickness exceeds the upper limit, the drive voltage and the hole transport layer are applied. Tend to be larger. Therefore, the thickness of the hole transport layer is preferably 1 to 1000 nm as described above, more preferably 2 nm to 500 nm, and still more preferably 5 nm to 200 nm.

(Light emitting layer)
The light emitting layer 56 usually includes an organic substance that mainly emits fluorescence or phosphorescence, and may further include a dopant material. As the organic substance, a low molecular compound and / or a high molecular compound is used, and a high molecular compound is preferably used. It is preferable that the light emitting layer 56 contains the high molecular compound whose number average molecular weight of polystyrene conversion is 10 < ³ > -10 < ⁸ >. Examples of the light emitting material constituting the light emitting layer 56 that can be used in this embodiment include the following. In addition, between the 1st electrode 52 and the 2nd electrode 58, not only one light emitting layer but a several light emitting layer may be arrange | positioned.

(Dye material)
Examples of the dye-based material include cyclopentamine derivatives, quinacridone derivatives, coumarin derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, Examples include pyrrole derivatives, thiophene ring compounds, pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, oxadiazole dimers (derivatives), and pyrazoline dimers.

(Metal complex materials)
Examples of metal complex materials include metal complexes that emit light from triplet excited states such as iridium complexes and platinum complexes, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolyl zinc complexes, benzothiazole zinc complexes, azomethyls. Zinc complex, porphyrin zinc complex, europium complex, etc., which has Al, Zn, Be or the like as the central metal or rare earth metal such as Tb, Eu, or Dy, and the ligand is oxadiazole, thiadiazole, phenylpyridine, phenylbenzo Examples thereof include metal complexes having an imidazole or quinoline structure.

(Polymer material)
Polymer materials include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and the above-mentioned dye bodies and metal complex light emitting materials. Things.

  Among the luminescent materials, materials that emit blue light include distyrylarylene derivatives, oxadiazole derivatives, and polymers thereof, polyvinylcarbazole derivatives, polyparaphenylene derivatives, polyfluorene derivatives, and the like. Of these, polymer materials such as polyvinyl carbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives are preferred.

  Examples of materials that emit green light include quinacridone derivatives, coumarin derivatives, and polymers thereof, polyparaphenylene vinylene derivatives, polyfluorene derivatives, and the like. Of these, polymer materials such as polyparaphenylene vinylene derivatives and polyfluorene derivatives are preferred.

  Examples of materials that emit red light include coumarin derivatives, thiophene ring compounds, and polymers thereof, polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives. Among these, polymer materials such as polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives are preferable.

(Dopant material)
A dopant can be added to the light emitting layer for the purpose of improving the light emission efficiency and changing the light emission wavelength. Examples of such dopants include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, phenoxazone, and the like. In addition, the thickness of such a light emitting layer is usually about 2 nm to 200 nm (20 to 2000 mm).

(Light-emitting layer deposition method)
As a method for forming a light emitting layer containing an organic substance, a method including directly applying a solution containing a light emitting material to the pixel region 59, a method of depositing the pixel region using a vacuum vapor deposition method, and light emission on a transfer substrate. For example, a method may be used in which a solution containing the material is applied once, this coating film is formed into a film, and the obtained film is transferred to the pixel region 59 to form a film indirectly. Specific examples of the solvent used for the film formation from the solution include the same solvents as those for dissolving the hole transport material when forming the hole transport layer from the above solution.

  As a method of applying a solution containing a light emitting material to the pixel region 59, or a method of applying a solution on a substrate to form a transfer film, a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, Bar coating method, roll coating method, wire bar coating method, dip coating method, slit coating method, capillary coating method, spray coating method, nozzle coating method and other coating methods, gravure printing method, screen printing method, flexographic printing method, offset A coating method such as a printing method such as a printing method, a reverse printing method, and an ink jet printing method can be used. A printing method such as a gravure printing method, a screen printing method, a flexographic printing method, an offset printing method, a reversal printing method, and an ink jet printing method is preferable in that pattern formation and multi-coloring are easy. In the case of a sublimable low-molecular compound, a vacuum deposition method can be used. Furthermore, a method of forming a light emitting layer only in a desired region by laser transfer or thermal transfer can be used.

(Electron injection layer)
The electron injection layer is a layer having a function of improving the electron injection efficiency from the cathode 58. As described above, the electron injection layer is provided between the electron transport layer and the cathode 58 or between the light emitting layer 56 and the cathode 58. As the electron injection layer, depending on the type of the light emitting layer 56, an alkali metal, an alkaline earth metal, an alloy containing one or more of the aforementioned metals, an oxide, halide and carbonate of the aforementioned metals, or the aforementioned And a mixture of these substances.

  Examples of alkali metals or oxides, halides and carbonates thereof include lithium, sodium, potassium, rubidium, cesium, lithium oxide, lithium fluoride, sodium oxide, sodium fluoride, potassium oxide, potassium fluoride, rubidium oxide. , Rubidium fluoride, cesium oxide, cesium fluoride, lithium carbonate and the like.

  Examples of alkaline earth metals or oxides, halides and carbonates thereof include magnesium, calcium, barium, strontium, magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride, calcium fluoride, barium oxide, fluoride Examples include barium, strontium oxide, strontium fluoride, and magnesium carbonate.

  Furthermore, a metal, a metal oxide, an organometallic compound doped with a metal salt, an organometallic complex compound, or a mixture thereof can also be used as a material for the electron injection layer.

This electron injection layer may have a stacked structure in which two or more layers are stacked. Specifically, Li / Ca etc. are mentioned. This electron injection layer is formed by vapor deposition, sputtering, printing, or the like.
The thickness of the electron injection layer is preferably about 1 nm to 1 μm.

(Electron transport layer)
The electron transport layer is a layer having a function of improving electron injection from the cathode 58, the electron injection layer, or the electron transport layer closer to the cathode 58. As the material for forming the electron transport layer, known materials can be used, such as oxadiazole derivatives, anthraquinodimethane or derivatives thereof, benzoquinone or derivatives thereof, naphthoquinone or derivatives thereof, anthraquinones or derivatives thereof, tetracyanoanthraquinodi. Examples include methane or its derivatives, fluorenone derivatives, diphenyldicyanoethylene or its derivatives, diphenoquinone derivatives, or metal complexes of 8-hydroxyquinoline or its derivatives, polyquinoline or its derivatives, polyquinoxaline or its derivatives, polyfluorene or its derivatives, etc. The

  Of these, oxadiazole derivatives, benzoquinone or derivatives thereof, anthraquinones or derivatives thereof, or metal complexes of 8-hydroxyquinoline or derivatives thereof, polyquinoline or derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorene or derivatives thereof are preferred, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, tris (8-quinolinol) aluminum, and polyquinoline are more preferable.

  The electron injection layer and the hole injection layer may be collectively referred to as a charge injection layer, and the electron transport layer and the hole transport layer may be collectively referred to as a charge transport layer.

(Second electrode)
The second electrode 58 in the first embodiment is an electrode disposed to face the first electrode 52 and serves as a cathode of the organic EL element 26. In the present invention, the second electrode described later is used. As shown in the embodiment, the second electrode 58 may be an anode. As such a cathode material, a material having a small work function and easy electron injection into the light emitting layer is preferable. The cathode material is preferably a material having high electrical conductivity and high visible light reflectance. Specific examples of such cathode materials include metals, metal oxides, alloys, graphite or graphite intercalation compounds, and inorganic semiconductors such as zinc oxide (ZnO).

  As the above-mentioned metal, an alkali metal, an alkaline earth metal, a transition metal, a Group 13 metal of the periodic table, or the like can be used. Specific examples of these metals include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin, and aluminum. , Scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and the like.

  Examples of the alloy include an alloy containing at least one of the above metals. Specifically, a magnesium-silver alloy, a magnesium-indium alloy, a magnesium-aluminum alloy, an indium-silver alloy, a lithium-aluminum alloy, Examples thereof include a lithium-magnesium alloy, a lithium-indium alloy, and a calcium-aluminum alloy.

  The cathode 58 is a light-transmitting electrode as required, and the material is a conductive oxide such as indium oxide, zinc oxide, tin oxide, ITO, IZO; polyaniline or a derivative thereof, polythiophene or a derivative thereof. And conductive organic substances such as

  Note that the second electrode 58 serving as a cathode may have a laminated structure of two or more layers. Moreover, an electron injection layer may be used as a cathode.

  The film thickness of the second electrode 58 serving as the cathode can be appropriately selected in consideration of electric conductivity and durability, but is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm. To 500 nm.

  Examples of the method for forming the second electrode 58 serving as the cathode include a vacuum deposition method, a sputtering method, and a laminating method in which a metal thin film is thermocompression bonded. The second electrode 58 may have a laminated structure of two or more layers.

(Protective layer)
After the second electrode 58 that is a cathode is formed as described above, the first electrode (anode) 52, the light emitting layer 56, and the second electrode (cathode) 58, which are basic structures, are sealed in order to protect them. A protective layer 70 is preferably formed. The protective layer 70 may be formed of a substrate similar to the substrate 51 already described, or any conventionally known suitable substrate that is opaque when not on the light extraction side of the emitted light (the protective layer 70 is protected). The substrate 70 may be used).

  The protective layer 70 usually has at least one inorganic layer and at least one organic layer. The number of stacked layers is determined as necessary, and basically, inorganic layers and organic layers are stacked alternately.

  Note that the plastic substrate has higher permeability of gases such as oxygen and water than the glass substrate. Since a light emitting substance such as the light emitting layer 56 is easily oxidized and easily deteriorated by contact with oxygen, water, or the like, when a plastic substrate is used as the substrate 51, the substrate is preliminarily subjected to a treatment for improving gas barrier properties. It is preferable. For example, it is preferable that a lower sealing film having a high barrier property against gas or the like is laminated on a plastic substrate, and then the organic EL element 26 is laminated on the lower sealing film. This lower sealing film is usually formed with the same configuration and the same material as the protective layer 70.

  In the organic EL element 26 of this embodiment, examples of the layer disposed at the position in contact with the first electrode 52 that is the anode include the hole injection layer, the hole transport layer, and the light emitting layer 56 as described above. It is done. The refractive indexes of the hole injection layer, the hole transport layer, and the light emitting layer 56 are usually about 1.5 to 1.8, respectively. The refractive index (n1) of the first electrode 52 satisfies the above-described formula (1), and is preferably set to be equal to or lower than the refractive index (n3) of the layer in contact with the first electrode 52.

  In the conventional bottom emission type organic EL element 26, ITO formed on a glass substrate has been used as an anode (first electrode). The refractive index (n1 ′) of ITO is about 2, and the refractive index (n2 ′) of the glass substrate is about 1.5. Among the hole injection layer, the hole transport layer, the light emitting layer, etc. Since the refractive index (n3 ′) of the portion in contact with the ITO is about 1.7, the conventional bottom emission type organic EL element has an ITO having a high refractive index between the glass substrate having a low refractive index and the light emitting layer. It was a sandwiched configuration. Therefore, a part of the light from the light emitting layer is reflected by the ITO by total reflection or the like, so that the light from the light emitting layer cannot be extracted efficiently.

  On the other hand, in the present embodiment, by using the substrate 51 and the first electrode 52 that satisfy the relationship of the above-described formula (1), the substrate 51, the first electrode 52, and the like can be compared with the conventional organic EL element. The organic EL element 26 having a small difference in refractive index from the portion in contact with the first electrode 52 among the hole injection layer, the hole transport layer, the light emitting layer, and the like can be configured. Thereby, it is possible to suppress the light from the light emitting layer 56 from being reflected by the first electrode 52, and to improve the light extraction efficiency of the organic EL element 26. In particular, if the first electrode 52 and the substrate 51 satisfying the relationship of n2 ≦ n1 ≦ n3 are used, the first of the substrate 51, the first electrode 52, the hole injection layer, the hole transport layer, the light emitting layer, etc. The difference in each refractive index from the portion in contact with the first electrode 52 can be further reduced, the light emitted from the light emitting layer 56 is suppressed from being reflected by the first electrode 52, and the light extraction efficiency of the organic EL element 26 is improved. This can be further improved. As a result, an organic EL element with high luminous efficiency can be realized.

  Further, if the light emitting layer 56 is formed on the flat first electrode 52 having a surface roughness Ra of 100 nm or less, variations in film thickness in each layer can be suppressed. Thereby, a short circuit due to the protrusion of the first electrode 52 can be eliminated.

In addition, since the first electrode 52 can be formed by a coating method, the first electrode 52 that is light transmissive can be formed by using a vacuum apparatus such as vacuum deposition and sputtering, or in a special process. Compared to the case where the first electrode 52 is formed, the first electrode 52 can be easily formed, and the cost can be reduced. Furthermore, since the characteristics of the first electrode 52 are determined by the types of the resin and the wire-shaped conductor, the shape of the wire-shaped conductor, and the like, the intended optical characteristics and electrical characteristics can be shown by simply selecting these. The first electrode 52 can be easily obtained.
Manufacture of the organic EL element of this embodiment is realizable by combining the formation process each demonstrated in the above-mentioned material description of each layer.

<Configuration example 2>
Next, Structural Example 2 of the organic EL element 26 will be described with reference to FIG. In addition, since it can be set as the same structure and manufacturing method about the component to which the code | symbol same as the structural example 1 already demonstrated with reference to FIG. 10 can be set, detailed description is abbreviate | omitted.
In the configuration example 2, the stacking order of each component of the organic EL element is reversed from that in the configuration example 1, and the difference between the configuration example 2 and the above-described configuration example 1 is the organic EL of the configuration example 1. The element 26 is a so-called bottom emission type in which light from the light emitting layer 56 is emitted from the substrate 51 side to the external environment through a light-transmitting anode (first electrode 52), whereas the organic EL element of the configuration example 2 26 is a so-called top emission type in which light from the light emitting layer 56 is emitted from the substrate 51 side to the external environment through the first electrode 52 which is a light transmissive anode. The substrate 51 of the configuration example 2 corresponds to the member described as the protective substrate in the configuration example 1. In the configuration example 2, the substrate 80 provided with the second electrode 58 corresponds to the substrate described in the configuration example 1 as the substrate provided with the first electrode 52 such as a TFT substrate.

  Also in the configuration example 2, the substrate 51 and the first electrode 52 satisfy the relationship of the above-described formula (1). Therefore, even when the organic EL element according to the present invention is configured as in the configuration example 2, the same operations and effects as those in the configuration example 1 already described can be obtained.

  The organic EL element 26 of the configuration example 1 shown in FIG. 10 transmits the light from the light emitting layer 56 through the first electrode 52 that is a light transmissive anode and emits the light from the light transmissive substrate 51 to the external environment. It has a bottom emission type structure. If the structure of the organic EL element of the configuration example 1 is tentatively referred to as a first structure, it is a bottom emission type structure in which the first electrode 52 is a cathode and the second electrode 58 that is an anode is provided on the protective layer 70 side. An organic EL element having a different structure (sometimes referred to as a second structure) can also be manufactured. If necessary, a design change such as replacement of the arrangement of the first functional layer 53 and the second functional layer 57 may be performed. The present invention can also be applied to such an organic EL element having the second structure.

In addition, the organic EL element 26 of the configuration example 2 shown in FIG. 11 transmits the emitted light from the light emitting layer 56 through the first electrode 52 that is a light transmitting anode and emits the light from the substrate 51 to the external environment. Has a mold structure. If the structure of the organic EL element of the configuration example 2 is tentatively referred to as a third structure, it is a top emission type structure in which the first electrode 52 is used as a cathode and the second electrode 58 serving as an anode is provided on the substrate 80 side. An organic EL element having a structure (sometimes referred to as a fourth structure) can also be manufactured. Also in this case, if necessary, a design change such as replacement of the arrangement of the first functional layer 53 and the second functional layer 57 may be performed. The present invention can also be applied to such an organic EL element having the fourth structure.
In addition, the light emitted from the light emitting layer 56 is transmitted through the first electrode 52 that is an anode and emitted from the substrate 51 to the external environment, and at the same time, the light is transmitted through the second electrode 53 that is a light transmissive cathode. A double emission type structure that emits light from the transmissive protective layer 70 to the outside environment can also be produced, and the present invention can be applied to such a double emission type organic EL element.

Hereinafter, the present invention will be described more specifically based on production examples, but the present invention is not limited to the following examples.
In Production Examples 1 to 3, an organic EL element having an electrode including a wire-like conductor in the electrode is manufactured while controlling the refractive index of the substrate and the electrode provided on the substrate within a specific range.

(Production Example 1)
As a wire-like conductor, a silver nanowire (major axis average length 1 μm, minor axis) whose surface is protected with an amino group-containing polymer dispersant (product name “Solsperse 24000SC” manufactured by IC Japan Ltd.) An average length of 10 nm) is used. 2 g of toluene dispersion of silver nanowire (containing 1.0 g of silver nanowire) and trimethylolpropane triacrylate (made by Shin-Nakamura Chemical Co., Ltd., trade name “NK Ester-TMPT”) which is a photocurable monomer serving as the film body 0.25 g is mixed, and further, 0.0025 g of a polymerization initiator (trade name “Irgacure 907” manufactured by Ciba-Geigy Corporation of Japan) is added. This mixed solution is applied to a 0.7 mm thick glass substrate (light transmissive substrate main body), heated on a hot plate at 110 ° C. for 20 minutes to dry the solvent, and further irradiated with a UV lamp (6000 mW / cm ^2). ) To obtain a first electrode having a thickness of 150 nm. By forming the film in this manner, a first electrode having a transmittance of 80% or more, a volume resistivity of 1 Ω · cm or less, and a surface roughness of 100 nm or less is obtained.

  The refractive index of the photocurable resin is 1.47, and the refractive index of the obtained first electrode is also 1.47. By using such a substrate and the first electrode, the organic EL element according to the above-described embodiment can be obtained. In the obtained organic EL element, the light extraction efficiency of the emitted light is improved.

(Production Example 2)
As a wire-like conductor, a silver nanowire (major axis average length 1 μm, minor axis) whose surface is protected with an amino group-containing polymer dispersant (product name “Solsperse 24000SC” manufactured by IC Japan Ltd.) An average length of 10 nm) is used. 1. 2 g of this silver nanowire in toluene dispersion (containing 1.0 g of silver nanowire) and a poly (ethylenedioxythiophene) / polystyrene sulfonic acid solution (trade name “BaytronP” manufactured by Starck Co., Ltd.) to be the membrane body. Mix with 5 g. This mixed solution is applied to a glass substrate (light transmissive substrate main body) having a thickness of 0.7 mm, heated on a hot plate at 200 ° C. for 20 minutes, and dried to obtain a first electrode having a thickness of 150 nm. By forming the film in this manner, a first electrode having a transmittance of 80% or more, a volume resistivity of 1 Ω · cm or less, and a surface roughness of 100 nm or less is obtained.

  The refractive index of “BaytronP” is 1.7, and the refractive index of the obtained first electrode is 1.7. By using such a substrate and the first electrode, the organic EL element according to the above-described embodiment can be obtained. In the obtained organic EL element, the light extraction efficiency of the emitted light is improved.

(Production Example 3)
As a wire-like conductor, a silver nanowire (major axis average length 1 μm, minor axis) whose surface is protected with an amino group-containing polymer dispersant (product name “Solsperse 24000SC” manufactured by IC Japan Ltd.) An average length of 10 nm) is used. A mixture of poly (ethylenedioxythiophene) / polystyrene sulfonic acid solution (trade name “BaytronP”, manufactured by Starck Co., Ltd.) 2.5 g mixed with 0.125 g of dimethyl sulfoxide, and silver nanowire toluene 2 g of dispersion (containing 1.0 g of silver nanowires) is mixed. This mixed solution is applied to a 0.7 mm thick glass substrate, heated at 200 ° C. for 20 minutes on a hot plate, and dried to obtain a conductive film having a thickness of 150 nm. By forming the film in this manner, a light-transmitting conductive film having a transmittance of 80% or more, a volume resistivity of 1 Ω · cm or less, and a surface roughness of 100 nm or less is obtained.

  The refractive index of “BaytronP” is 1.7, and the refractive index of the obtained light-transmitting conductive film is also 1.7. By using such a substrate and the first electrode, the organic EL element according to the above-described embodiment can be obtained. In the obtained organic EL element, the light extraction efficiency is improved.

  In Production Examples 1 to 3 described above, an organic EL element in which the refractive index between the substrate and the light-transmitting first electrode is controlled within a specific range and a wire-like conductor is provided in the first electrode is manufactured. Then, the refractive indexes of the light transmissive substrate main body and the first electrode are controlled within the range defined by the formula (1) already described.

It is a schematic explanatory drawing (1) of an illumination light communication system. It is a schematic explanatory drawing (2) of an illumination light communication system. It is a schematic explanatory drawing (3) of an illumination light communication system. It is a schematic explanatory drawing (4) of an illumination light communication system. It is a circuit diagram of the light emission unit of a current program system. It is a circuit diagram of the light emitting element of a voltage program system. It is operation | movement explanatory drawing of a light emission unit. It is a schematic explanatory drawing (5) of an illumination light communication system. It is operation | movement explanatory drawing of the light source for illumination. It is a schematic sectional drawing (1) of an organic EL element. It is a schematic sectional drawing (2) of an organic EL element.

Explanation of symbols

10: Illumination light communication system 20: Transmitter 22: Light source for illumination 24: Light emitting unit 23: Sub light source 23A: First sub light source 23B: Second sub light source 23C: Third sub light source 23D: Fourth sub light source 26: Organic EL element 28: control circuit 29: serial / parallel conversion circuit 30: receiving device 32: light receiving unit 34: demodulation unit 36: lens 38: parallel / serial conversion circuit 42: scanning line driving circuit 44: data line driving circuit 51: substrate 52: first electrode 53: first functional layer 56: light emitting layer 57: second functional layer 58: second electrode 59: pixel region 70: protective layer (protective substrate)
80: Substrate X: Data line Y: Scan line

Claims (11)

A transmission device including an illumination light source that emits modulated light modulated based on transmission data,
The illumination light source includes a substrate exhibiting light transparency, and an organic electroluminescence element provided in contact with the substrate,
The organic electroluminescent element includes a first electrode that is light transmissive and disposed in contact with the substrate, a second electrode, and a light emitting layer provided between the first electrode and the second electrode. Including
When the refractive index of the first electrode is n1 and the refractive index of the substrate is n2, n1 and n2 are respectively expressed by the following formula (1)

The transmission apparatus for illumination light communication systems which satisfy | fills.   2. The transmission device according to claim 1, wherein the first electrode has a light transmittance of 80% or more, a volume resistivity of 1 Ω · cm or less, and a surface roughness of 100 nm or less. The transmission device according to claim 1, wherein the illumination light source includes a plurality of the organic electroluminescence elements each having a light emission area of 10 ⁻⁸ cm ² to 10 ⁻¹ cm ² .   The transmission according to any one of claims 1 to 3, wherein the illumination light source includes a communication organic electroluminescence element that emits modulated light and an illumination organic electroluminescence element that emits non-modulated light. apparatus.   The light emitting layer of the organic electroluminescent element for communication is formed using a light emitting material that emits fluorescence, and the light emitting layer of the organic electroluminescent element for illumination is formed using a light emitting material that emits phosphorescence. The transmission device according to claim 4.   6. The transmission device according to claim 1, wherein the first electrode includes a light-transmitting film main body, and a wire-shaped conductor disposed in the film main body and having conductivity.   The transmission device according to claim 6, wherein a diameter of the wire-like conductor is 200 nm or less.   The transmission device according to claim 7, wherein the wire-like conductor forms a network structure in the film main body.   The transmitting apparatus according to claim 6, wherein the film main body includes a resin having conductivity.   The transmission device according to any one of claims 1 to 9, wherein the first electrode is formed by a coating method.   A transmitter according to any one of claims 1 to 10, further comprising an illumination light source that emits modulated light, receives the modulated light emitted from the illumination light source, converts the modulated light into an electrical signal, and An illumination light communication system comprising: a reception device that demodulates a signal and generates reception data.

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