EP0302748A2

EP0302748A2 - Discharge lamp type display device

Info

Publication number: EP0302748A2
Application number: EP88307261A
Authority: EP
Inventors: Shing Cheung Chow
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-08-06
Filing date: 1988-08-05
Publication date: 1989-02-08
Also published as: KR890004264A; AU2003688A; AU607520B2; EP0302748A3

Abstract

A discharge lamp type display device which comprises a discharge vessel including a first (10) and a second (12) transparent glass plate arranged in parallel to each other, xenon gas serving as a discharge material and enclosed in a discharge space defined between the first and second glass plates, a fluorescent layer (16) coated on a predetermined position of the inner surface of at least one of the first and second glass plates and having a thickness of 0.01 to 1 mm, a first electrode (20) formed on the outer surface of the first glass plate, and a second (22) electrode formed on the outer surface of the second glass plate.

Description

Background of the Invention

1. Field of the Invention

The present invention relates to a flat discharge lamp type display device.

2. Description of the Prior Art

Conventionally, a discharge lamp type display device represented by a neon sign is well known. In general, such a display device includes a plurality of tubular discharge lamps formed in predetermined shapes and disposed in such a specific arrangement as to transmit information. Such a prior art neon sign, employing a plurality of tubular discharge lamps, is difficult to manufacture, and the electrical circuit to activate the discharge lamps for luminous discharge is complicated and high in cost. In addition, for more distinct display of the information, the tubular discharge lamps must be arranged more closely, but the prior art device employing a number of discharge lamps has limits in itself. Further, in the conventional display device using tubular discharge lamps, the information expressible by a dynamic display also has limits.

Summary of the Invention

It is, accordingly, a general object of the present invention to provide a flat discharge lamp type display device which avoid the difficulties encountered in the prior art discharge lamp type display device.
It is a more specific object of the present invention to provide such a display device which may display information distinctly and which may generate high luminous output.
It is another object of the present invention to provide such a display device which is easy to manufacture and which has a simple electrical circuit to activate the display device for luminous discharge.
It is still another object of the present invention to provide such a display device which may display information with dynamic effects.
It is a further object of the present invention to provide such a display device whose strength is improved.
It is a still further object of the present invention to provide such a display device having a large display area.
It is a still further object of the present invention to provide a simple method for manufacturing discharge lamp type display devices.
Broadly described, the present invention provides a discharge lamp type display device which comprises a discharge vessel including a first and a second transparent glass plate arranged in parallel to each other, xenon gas serving as a discharge material and enclosed in a discharge space defined between the first and second glass plates, a fluorescent layer coated on a predetermined position of the inner surface of at least one of the first and second glass plates and having a thickness of 0.01 to 1 mm, a first electrode formed on the outer surface of the first glass plate, and a second electrode formed on the outer surface of the second glass plate.
In another aspect, the present invention provides a discharge lamp type display device which comprises a discharge vessel including a first and a second transparent glass plate arranged in parallel to each other, xenon gas serving as a discharge material and enclosed in a discharge space defined between the first and second glass plates, a fluorescent layer coated on a predetermined position of the inner surface of at least one of the first and second glass plates and having a thickness of 0.01 to 1 mm, a first electrode formed on the outer surface of the first glass plate, and a second electrode mounted on one end of the discharge vessel and extending into the discharge space, voltage impressing means for impresseing to the second electrode a voltage having frequency of 0.5 to 20 kHz and varying peak values, and grounding means for grounding the first electrode.
In still another aspect, the present invention provides a discharge lamp type display device which comprises a discharge vessel including a first and a second transparent glass plate arranged in parallel to each other, xenon gas serving as a discharge material and enclosed in a discharge space defined between the first and second glass plates, a fluorescent layer coated on a predetermined position of the inner surface of at least one of the first and second glass plates and having a thickness of 0.01 to 1 mm, a first electrode formed on the outer surface of the first glass plate, a protective plate disposed over the second glass plate with a predetermined space thereto and serving to protect the first and second glass plates, and an electrically conductive liquid enclosed in the space defined between the second glass plate and the protective plate and serving as a second electrode.
In a further aspect, the present invention provides a discharge lamp type display device which comprises a discharge vessel inclduing a transparent glass plate, and a transparent glass member having a glass flat portion disposed in parallel to the galss plate, a galss sealing portion formed along the periphery of the glass flat portion and bonded to the glass plate to form the discharge vessel, the glass sealing portion being made of the same glass as the glass flat portion and having a predetermined height, and a plurality of spacers disposed between the glass plate and the glass flat portion, the plurality of spacers being made of the same glass as the glass flat portion and formed to have the same height as the glass sealing portion; xenon gas serving as a discharge material and enclosed in the discharge vessel; a fluorescent layer coated on a predetermined position of the inner surface of at least one of the glass plate and the glass flat portion and having a thickness of 0.01 to 1 mm; a first electrode formed on the outer surface of the glass plate; and a second electrode formed on the outer surface of the glass member.
In a still further aspect, the present invention provides a method for manufacturing a discharge lamp type display device including a discharge vessel having a pair of transparent glass plates and a plurality of spacers provided in between the glass plates, a discharge gas enclosed in the discharge vessel, a fluorescent layer coated on a predetermined position of the inner surface of at least one of the glass plates, and at least one electrode formed on the interior or the exterior of the discharge vessel. The method comprises the steps of preparing a first and a second glass plate; attaching masks on one surface of the first glass plate at the periphery thereof and at the portion where the spacers are formed; chemically etching the first glass plate into a predetermined depth; combining and sealing the first and second glass plates to form the discharge vessel having the spacers; evacuating the discharge vessel; and filling the discharge vessel with a discharge gas at a predetermined pressure.
According to the present invention, the discharge vessel of the display device is formed of the glass plates, with the fluorescent layer coated on the inner surface of at least one of the glass plates. Desired information can be closely written on the glass plate by properly selecting a pattern of the fluorescent layer and a fluorescent material for forming the pattern and locating the pattern on a predetermined position of the glass plate. Therefore, the predetermined information may be displayed distinctly. Further, the discharge gas employed is xenon which has a large ultraviolet output and little heat loss, and the thickness of the fluorescent layer is kept within such a range from 0.01 to 1 mm as to provide high luminous output. As the predetermined information can be displayed by a single discharge vessel, the display device can be easily manufactured and a simple electrical circuit can be employed to activate the same for luminous discharge.
According to the second aspect of the present invention, a voltage having frequency of 0.5 to 20 kHz and varying peak values is applied to the electrode within the discharge vessel and hence, the luminous output distribution of a positive column formed in the discharge space may be varied with the varying voltage as time elapses. Thus, various information may be displayed with dynamic effects.
According to the third aspect of the present invention, the display device includes the protective plate for protecting the first and second glass plates, thereby increasing the strength of the display device. The electrically conductive liquid enclosed between the first glass plate and the protective plate also protects the first glass plate, thereby further increasing the strength of the display device.
According to the fourth aspect of the present invention, a plurality of spacers having the same height as the glass sealing portion are provided between the glass plate and the glass flat portion, thereby increasing the glass components forming the discharge vessel. Thus, the discharge vessel can employ large-sized glass plates, thereby making it possible to manufacture display devices having a large display area.
According to the present method for manufacturing a discharge lamp type display device, the spacers and the glass sealing portion for sealing the discharge vessel may be formed at the same time by etching the first glass plate by way of masks. Thus, the height of the glass sealing portion and that of the spacers may be precisely uniformed. The spacers perfectly support the glass plates so that in the evacuating step of the discharge vessel, any possible damage to the discharge vessel may be reliably prevented. Further, after the display device has been made, the spacers also serve to support the glass plates so that no possible internal stress may be developed in the glass plates. Thus, display devices having improved strength may be easily manufactured.
The present invention will become more fully apparent from the claims and the description as it proceeds in connection with the drawings.

Brief Description of the Drawings

FIG. 1 is a perspective view of a discharge lamp type display device according to a first embodiment of the present invention;
FIG. 2 is a sectional view taken along line II-II in FIG.1;
FIG. 3 is a schematic representation illustrating various information indicative by the fluorescent layer;
FIG. 4 is a perspective veiw of a discharge lamp type display device according to a second embodiment of the present invention;
FIG. 5 is a sectional view taken along line V-V in FIG. 4;
FIG. 6 is a perspective view of a discharge lamp type display device according to a third embodiment of the present invention;
FIG. 7 is a sectional view taken along line VII-VII in FIG. 6;
FIG. 8 is a schematic view illustrating how to activate the display device according to the third embodiment;
FIG. 9 is a perspective view of a discharge lamp type display device according to a fourth embodiment of the present invention;
FIG. 10 is a sectional view taken along line X-X in FIG. 9;
FIG. 11 is a perspective view of a discharge lamp type display device according to a fifth embodiment of the present invention;
FIG. 12 is a sectional view taken along line XII-XII in FIG. 11;
FIG. 13 is a perspective view of a discharge lamp type display device according to a sixth embodiment of the present invention;
FIG. 14 is a sectional view taken along line XIV-XIV in FIG. 13;
FIG. 15 is a schematic view illustrating how to activate the display device according to the sixth embodiment;
FIG. 16 is a perspective view of a discharge lamp type display device according to a seventh embodiment of the present invention;
FIG. 17 is a sectional view taken along line XVII-XVII in FIG. 16;
FIG. 18 is a perspective view of a discharge lamp type display device according to an eighth embodiment of the present invention;
FIG. 19 is a sectional view taken along line XIX-XIX in FIG. 18;
FIG. 20 is a perspective view of a discharge lamp type display device according to a ninth embodiment of the present invention;
FIG. 21 is a sectional view taken along line XXI-XXI in FIG. 20;
FIG. 22 is a perspective view of a discharge lamp type display device according to a tenth embodiment of the present invention;
FIG. 23 is a sectional view taken along line XXIII-XXIII in FIG. 22;
FIG. 24 is a perspective view of a discharge lamp type display device according to an 11th embodiment of the present invention;
FIG. 25 is a sectional view taken along line XXV-XXV in FIG. 24;
FIG. 26 is a perspective view of a discharge lamp type display device according to a 12th embodiment of the present invention;
FIG. 27 is a sectional view taken along line XXVII-XXVII in FIG. 26;
FIG. 28 is a perspective view of a discharge lamp type display device according to a 13th embodiment of the present invention;
FIG. 29 is a sectional view taken along line XXIX-XXIX in FIG. 28;
FIG. 30 is a perspective view of a discharge lamp type display device according to a 14th embodiment of the present invention;
FIG. 31 is a sectional view taken along line XXXI-XXXI in FIG. 30;
FIG. 32 is a schematic view illustrating a method for manufacturing a discharge lamp type display device according to the present invention;
FIG. 33 is a schematic diagram of an electrical circuit to activate the display device for luminous discharge;
FIG. 34 and 35 are waveform diagrams illustrating the control signal generated by a control signal generator;
FIG. 36 is a schematic diagram of another electrical circuit to activate the display device for luminous discharge;
FIG. 37 is a block diagram of a control signal generator;
FIG. 38 is a diagram illustrating a group of output signal waveforms, wherein FIG. 38(a) shows a pulse signal generated by a pulse signal generator, FIG. 38(b) shows a sawtooth signal generated by a sawtooth signal generator, and FIG. 38(c) shows a sawtooth control signal generated by the control signal generator;
FIG. 39 is a schematic view illustrating the dynamic display effect of the display device activated by the circuit in FIG. 36 for luminous discharge;
FIG. 40 is a schematic view illustrating the relation between the length of the internal electrode and the dimensions of the discharge space of the display device;
FIG. 41 is a diagram illustrating a group of a pulse signals generated by the pulse signal generator, wherein FIG. 41(a) shows a pulse waveform having a pulse width of t, FIG. 41(b) shows a pulse waveform having a pulse width of t/2, and FIG. 41(c) shows a pulse waveform having a pulse width of 2t;
FIG. 42 is a diagram illustrating a group of sawtooth control signal waveforms generated by the control signal generator, wherein FIG. 42(a) shows a signal waveform having a period of T₁, FIG. 42(b) shows a signal waveform having a period of T₁/2, and FIG. 42(c) shows a signal waveform having a period of 2T₁;
FIG. 43 is a block diagram of a control signal generator for generating triangular control signals; and
FIG. 44 is a diagram illustrating a group of output signal waveform, wherein FIG. 44(a) shows a pulse signal waveform generated by the pulse generator, FIG. 44(b) shows a triangular signal waveform generated by a triangular signal generator, and FIG. 44(c) shows a triangular control signal waveform generated by the control signal generator.

Detailed Description of Preferred Embodiments

Referring now to FIGS. 1 and 2, shown therein is a flat discharge lamp type display device according to a first embodiment of the present invention. As shown therein, the display device includes a first glass plate 10 and a second glass plate 12 disposed in parallel to each other, and they are made of soft glass such as transparent soda glass, or hard glass such as borosilicate glass. Between the first and second glass platees 10 and 12, a sealing glass member 14 is provided having a thermal expansion coefficient substantially equal to that of the first and second glass plates, and thus, the first glass plate 10, second glass plate 12 and sealing glass member 14 form a discharge vessel. The interior of the discharge vessel is evacuated and is then filled with xenon gas at a pressure from several to 100 mmHg, for example, at 50 mmHg. Xenon, which has a high output in the ultraviolet region and little heat loss, is suitable for use as a discharge gas. Apart from the above advantage, employment of xenon gas has a further advantage of reducing blackening of the discharge vessel through scattering of the electrode material with the result of extended life of the display device. Other rare gases such as neon, argon and krypton may be used as a discharge gas. Further, enclosure of a getter material in the discharge vessel causes no side effect and consequently no fear of environmental pullution.
A fluorescent layer 16 having a predetermined pattern is formed on the inner surface of the second glass plate 12. In case the fluorescet layer 16 is formed of a single fluorescent material, a single color light is obtainable, but if a plurality of fluorescent materials are employed to form respective predetermined patterns, a display composed of various color patterns is achieved by luminous discharge. If the fluorescent layer 16 is formed of spot-like fluorescent elements 18 as shown in this embodiment, luminous output is obtained not only from the surface of the fluorescent elements 18 contacting the second glass plate 12 but also from the sides thereof, so that the luminous output obtainable is higher than that obtained by the fluorescent layer formed evenly on the whole inner surface of the second glass plate 12. The fluorescent layer 16 has a thickness from 0.01 to 1mm, for example 0.12 mm, so that absorption of light in the fluorescent layer 16 may be little, and consequently high luminous output is obtainable. In case of the thickness less than 0.01 mm, it is disadvantageous in that the fluorescent layer 16 would be too thin to provide satisfactory luminous output and accompanied with fluctuation of thickness, which would cause substantial change in the luminous output from the fluorescent layer 16. In case of the thickness more than 1 mm, it is disadvantageous in that the luminous output from the fluorescent layer 16 would be substantially saturated or lowered. The fluorescent layer 16 may be formed, for example, by silk printing. An emulsion is applied onto a fine mesh of nylon, and a film having a net pattern to be printed is tightly attached to the mesh and exposed to light. Then the mesh with the emulsion is developed and fixed, and the emulsion at the unexposed portion is washed off. The mesh is then placed on the second glass plate 12 and fluorescent material powders are applied on the mesh, so that the fluorescent layer 16 may be printed on the second glass plate 12 through the mesh.
A first electrode 20 is provided on the outer surface of the first glass plate 10. The first electrode 20 is formed by applying, for example, an opaque carbon paint on the outer surface of the first glass plate 10. A second electrode 22 is provided on the outer surface of the second glass plate 12. The second electrode 22 is formed of an electrically conductive and transparent film such as of tin oxide. Such a film of tin oxide if formed by spraying an aqueous solution such as of tin halide under atomized condition onto the outer surface of the second glass plate 12 heated at 500 to 600°C. With this arrangement of the first electrode 20 formed of the opaque material and the second electrode 22 formed of the transparent material, light is emitted only from the second glass plate 12. If it is desired to obtain discharge light from both of the first and second glass plates 10 and 12, the first electrode 20 may be also formed of an electrically conductive and transparent film such as of tin oxide. In such a case, it is preferable to provide a fluorescent layer of a predetermined pattern also on the inner surface of the first glass plate 10. Lead wires 28 and 29 are electrically connected to the first and second electrodes 20 and 22, respectively.
The fluorescent layer 16 may be arranged to have various patterns. It may be arranged to display, for example, dots as shown in FIG. 3(a), characters as shown in FIG. 3(b), or graphics, symbols, pictures, or the like. Further, as shown in FIG. 3(c), the fluorescent layer 16 may be formed in grids. Such an arrangement permits the fluorescent layer 16 to give out discharge light also from the sides thereof, as is the case in the one formed in spots, so that the display device can increase the luminous output.
In the above embodiment, desired information can be displayed by a single discharge lamp, so that the display device can be manufactured easily and a simple electrical circuit can be employed to activate the display device for luminous discharge. Further, the fluorescent layer 16 having a predetermined pattern and adapted for radiating lights having various wavelengths is provided at a desired position on the inner surface of the second glass plate 12, permitting close and distinct display of information. Xenon gas employed as a discharge gas has a large ultraviolet output and little heat loss, and the fluorescent layer 16 has a thickness from 0.01 to 1 mm, assuring quite effective luminous output.
FIGS 4 and 5 show a second embodiment of the present invention. The second embodiment is different from the first embodiment in that there is no electrode provided on the outer surface of the second glass plate 12 but an internal electrode 30 is provided at one end of the discharge vessel and extends into a discharge space defined between the first and second glass plates 10 and 12. The internal electrode 30 serves as a second electrode and is sealed in a glass tube 32 communicating with the discharge space. In case the glass tube 32 is made of soft glass, Dumet wire is preferably used for the electrode 30; in case of hard glass, a tungsten wire is preferably used. Other materials suitable for the electrode 30 are nickel (Ni), copper (Cu), titanium (Ti), tantalum (Ta) and zirconium (Zr). Titanium, tantalum and zirconium, which have getter effect, are more preferable. When any of such materials as described above is used for the electrode 30, the glass material must be selected so as to have a thermal expansion coefficient corresponding thereto. The glass tube 32 has an exhaust port 34 through which it can be evacuated. In other respects, the second embodiment is similar to the first embodiment. Like parts are given like reference numbers and their description will not be repeated. The second embodiment can give an effect similar to that of the first embodiment, and application of high frequency voltage whose peak value changes as time elapses to the internal electrode 30 enables various dynamic effects on the information to be displayed.
FIGS. 6 to 8 show a third embodiment of the present invention. The third embodiment is different from the second embodiment in that there is no electrode provided on the outer surface of the first glass plate 10, but only the internal electrode 30 is provided at one end of the discharge vessel and extends into the discharge space. The internal electrode 30 is equal to the one employed in the second embodiment, and is sealed in the glass tube 32 communicating with the discharge space. In other respects, the third embodiment is similar to the second embodiment. Like parts are given like reference numbers and their description will not be repeated.
As shown in FIG. 8, in order to activate the display device of the third embodiment for luminous discharge, the display device (now designated by the reference number 40) is put in a water tank 38 containing water 36. An electrical circuit 42 for activating the display device 40 has two lead wires 43 and 44, one lead wire 43 connected to the internal electrode 30 and the other 44 inserted into the water 36. As shown in FIG. 8, no trouble occurs even when goldfish 46 are in the water tank 38. The display device according to the third embodiment has an effect similar to that of the first embodiment, and furthermore, it can provide a novel display as shown in FIG. 8.
FIGS. 9 and 10 show a flat discharge lamp type display device according to a fourth embodiment of the present invention. As shown therein, the display device includes a first glass plate 110 and a second glass plate 112 disposed in parallel to each other, and they are made of soft glass such as transparent soda glass, or hard glass such as borosilicate glass. Between the first and second glass plates 110 and 112, a sealing glass member 114 is provided having a thermal expansion coefficient substantially equal to that of the first and second glass plates, and thus, the first glass plate 110, second glass plate 112 and sealing glass member 114 form a discharge vessel. As with the first embodiment, the interior of the discharge vessel is evacuated and is then filled with xenon gas at a pressure from several to 100 mmHg, for example, at 50 mmHg.
A fluorescent layer 116 having a pattern shown in FIG. 9 is formed on the inner surface of the second glass plate 112. As with the first embodiment, in case the fluorescent layer 116 is formed of a single fluorescent material, a single color light is obtainable, but if a plurality of fluorescent materials are employed to form respective predetermined patterns, a display composed of various color patterns is achieved by luminous discharge.
A first electrode 120 is provided on the outer surface of the first glass plate 110. The first electrode 120 is formed by applying, for example, an opaque carbon paint on the outer surface of the first glass plate 110. A second electrode 122 is provided on the outer surface of the second glass plate 112. The second electrode 122 is formed of a conductive aqueous solution containing a small amount of, for example, 0.001 to 0.01 parts by weight of sodium chloride NaCl or sodium hydroxide NaOH. A protective plate 124 made of a transparent acrylic plate is provided on the second electrode 122. Around the protective plate 124, the second electrode 122 and the second glass plate 112, a sealing member 126 made of silicone is provided to receive the second electrode 122 between the protective plate 124 and the second glass plate 122. Lead wires 128 and 129 are electrically connected to the first electrode 120 and the second electrode 122, respectively.
The protective plate 124 is adapted for protecting the first and second glass plates 110 and 112 so as to increase the strength of glass as well as for transmitting the light generated by discharge. The second electrode 122 formed of the conductive aqueous solution is also adapted for protecting the first and second glass plates as well as for transmitting the light externally. Thus, provision of the protective plate 124 and the second electrode 122 increases the strength of the display device. With this arrangment of the first electrode 120 formed of the opaque material and the second electrode 122 formed of the transparent material, light is emitted only from the protective plate 124. If it is desired to obtain discharge light from both of the first glass plate 110 and the protective plate 124, the first electrode 120 may be also formed of an electrically conductive transparent film such as of tin oxide. Such a film of tin oxide is formed by spraying an aqueous solution such as of tin halide under atomized condition onto the outer surface of the second glass plate 12 heated at 500 to 600°C. In such a case, it is preferable to provide a fluorescent layer of a predetermined pattern also on the inner surface of the first glass plate 110.
FIGS. 11 and 12 show a fifth embodiment of the present invention. The fifth embodiment is different from the fourth embodiment in that there is no electrode provided on the outer surface of the first glass plate 110 but an internal electrode 130 is provided at one end of the discharge vessel and extends into a discharge space defined between the first and second glass plates 110 and 112. The internal electrode 130 serves as a first electrode and is sealed in a glass tube 132 communicating with the discharge space. As with the second embodiment, in case the glass tube 132 is made of soft glass, Dumet wire is preferably used for the electrode 130; in case of hard glass, a tungsten wire is preferably used. The glass tube 132 has an exhaust port 134 through which it can be evacuated. In other respects, the fifth embodiment is similar to the fourth embodiment. Like parts are given like reference numbers and their description will not be repeated. The fifth embodiment can give an effect similar to that of the fourth embodiment, and application of high frequency voltage whose peak value changes as time elapses to the internal electrode 130 enables various dynamic effects on the information to be displayed.
FIGS. 13 to 15 show a sixth embodiment of the present invention. The sixth embodiment is different from the fifth embidiment in that there is no internal electrode extending into the discharge space. In other respects, the sixth embodiment is similar to the fifth embodiment. Like parts are given like reference numbers and their description will not be repeated.
As shown in FIG. 15, in order to activate the display device of the sixth embodiment for luminous discharge, the display device (now designated by the reference number 140) is put in a water tank 138 containing water 136. An electrical circuit 142 for activating the display device 140 has two lead wires 143 and 144, one lead wire 143 connected to the second electrode 122 and the other 144 inserted into the water 136. As shown in FIG. 15, no trouble occurs even when goldfish 146 are in the water tank 138. The display device according to the sixth embodiment has an effect similar to that of the fourth embodiment, and furthermore, it can provide a novel display as shown in FIG. 15.
FIGS. 16 and 17 show a seventh embodiment of the present invention, the same as the fourth embodiment insofar as the second glass plate 112 and the sealing glass member 114 are concerned, but employing a modified first electrode 121 provided on the outer surface of the first glass plate 110. The first electrode 121 is formed of the same conductive aqueous solution as the second electrode 122 of the fourth embodiment. A protective plate 125 made of a transparent acrylic plate is provided on the first electrode 121. Around the protective plate 125, the first electrode 121 and the first glass plate 110, a sealing member 127 made of silicone is provided to receive the first electrode 121 between the protective plate 125 and the first glass plate 110. A lead wire 131 is electrically connected to the first electrode 121. A fluorescent layer 117 is provided on the inner surface of the first glass plate 110. In other respects, the eighth embodiment is similar to the fourth embodiment. Like parts are given like reference numbers and their description will not be repeated. In this embodiment, the same effect as in the fourth embodiment may be obtained and further, luminous output may be obtained from both of the first and second glass plates 110 and 112. Moreover, the strength of the display device may be further increased by the addition of the protective plate 125 and the first electrode 121.
FIGS. 18 and 19 show a flat discharge lamp type display device according to an eighth embodiment of the present invention. As shown therein, the display device includes a glass member 210 and a glass plate 212. The glass member 210 and the glass plate 212 are made of soft glass such as transparent soda glass, or hard glass such as transparent borosilicate glass. The glass member 210 is comprised of a glass flat portion 213 disposed in parallel to the glass plate 212, a glass sealing portion 214 having a predetermined height and formed along the periphery of the glass flat portion 213, and a plurality of spacers or glass support members 215 having the same height as the glass sealing portion 214 and disposed between the glass plate 212 and the glass flat portion 213. The glass sealing portion 214 is bonded to the glass plate 212 by low-melting glass to thereby form a discharge vessel. The flat portion 213, the sealing portion 214 and the support members 215 are of the same glass and are formed integrally. Since the support members 215 support the glass member 210 and the glass plate 212, the strength of the glass member 210 and the glass plate 212 may effectively be increased. Thus, the glass member 210 and the glass plate 212 may have a large area, making it possible to manufacture large-sized display devices. As with the first embodiment, the interior of the discharge vessel is evacuated and is then filled with xenon gas at a pressure from several to 100 mmHg, for example, at 50 mmHg.
A fluorescent layer 216 corresponding to the fluorescent layer 116 of the fourth embodiment is formed on the inner surface of the glass plate 217.
A first electrode 220 is provided on the outer surface of the glass flat portion 213. The first electrode 220 is formed by applying, for example, an opaque carbon paint on the outer surface of the glass flat portion 213. A second electrode 222 is provided on the outer surface of the glass plate 212. As with the first embodiment, the second electrode 222 is formed of an electrically conductive and transparent film such as of tin oxide. Lead wires 228 and 229 are electrically connected to the first and second electrodes 220 and 222, respectively.
In the eight embodiemnt, the glass support members 215 having the same height as the glass sealing portion 214 are provided between the glass plate 212 and the glass flat portion 213. Thus, the display device can employ large-sized glass plates, thereby making it possible to manufacture display devices having a large display area.
FIGS. 20 and 21 show a ninth embodiment of the present invention. The ninth embodiment is different from the first embodiment in that there is no electrode provided on the outer surface of the second glass plate 212 but an internal electrode 230 is provided at one end of the discharge vessel and extends into a discarge space defined between the glass plate 212 and the glass flat portion 213. The internal electrode 230 serves as a second electrode and is sealed in a glass tube 232 communicating with the discharge space. The glass tube 232 has an exhaust port 234 through which it can be evacuated. In other respects, the ninth embodiment is similar to the eighth embodiment. Like parts are given like reference numbers and their description will not be repeated. The ninth embodiment can give an effect similar to that of the eighth embodiment, and application of high frequency voltage whose peak value changes as time elapses to the internal electrode 230 enables various dynamic effects on the information to be displayed.
FIGS. 22 and 23 show a tenth embodiment of th present invention. The tenth embodiment is different from the ninth embodiment in that there is no electrode provided on the outer surface of the glass flat portion 213, but only the internal electrode 230 is provided at one end of the discharge vessel and extends into the discahrge space. The internal electrode 230 is equal to the one employed in the ninth embodiment and is sealed in the glass tube 232 communicating with the discharge space. In other respects, the tenth embodiment is similar to the ninth embodiment. Like parts are given like reference number and their description will not be repeated. Further, the system and electrical circuit to activate the display device of the tenth embodiment is substantially the same as those of the third embodiment illustrated in FIG. 8 and any further description will be omitted.
FIGS. 24 and 25 show an 11th embodiment similar to the 8th embodiment wherein like reference numbers refer to like parts that will not be redescribed. As shown therein, the 11th embodiment includes a modified second electrode 223, a protective plate 224 and a sealing member 226. All of these parts 223, 224 and 226 correspond to their couterparts 122, 124 and 126, respectively, of the fourth embodiment illustrated in FIGS. 9 and 10 and any further description will be omitted. In this embodiment, since the display device includes the second electrode 223 formed of aqueous solution and the protective plate 224 to protect the glass components, the strength of the display device may effectively be increased.
FIGS. 26 and 27 show a 12th embodiment of the present invention. The 12th embodiment is different from the 11th embodiment in that there is no electrode provided on the outer surface of the glass flat portion 213 but an internal electrode 230A is provided at one end of the discharge vessel and extends into a discharge space defined between the glass plate 212 and the glass flat portion 213. The internal electrode 230A serves as a second electrode and is sealed in a glass tube 232A communicating with the discharge space. The glass tube 232A has an exhaust port 234A through which it can be evacuated. In other respects, the 12th embodiment is similar to the 11th embodiment. Like parts are given like reference numbers and their description will not be repeated. It will be noted that the effect of the 12th embodiment is similar to that of the 9th embodiment.
FIGS. 28 and 29 show a 13th embodiment of the present invention. The 13th embodiment is different from the 12th embodiment in that there is no internal electrode extending into the discharge space. In other respects, the 13th embodiment is similar to the 12th embodiment. Like parts are given like reference numbers and their description will not be repeated. Further, the system and electrical circuit to activate the display device of the 13th embodiment is substantially the same as those of the 6th embodiment illustrated in FIG. 15 and any further description will be omitted.
FIGS. 30 and 31 show a 14th embodiment similar to the 11th embodiment wherein like reference numbers refer to like parts that will not be redescribed. As shown therein, the 14th embodiment includes a modified first electrode 221 provided on the outer surface of the glass flat portion 213. The first electrode 221 is formed of the same conductive aqueous solution as the second electrode 122 of the fourth embodiment. A protective plate 225 made of a transparent acrylic plate is provided on the first electrode 221. A sealing member 227 made of silicone is provided to seal the first electrode 221 between the protective plate 225 and the glass flat portion 213. The inner surface of the glass flat portion 213 is provided with a fluorescent layer 217 to obtain luminous output also from the protective plate 225. A lead wire 231 is electrically connected to the first electrode 221. In this embodiment, the same effect as in the 11th embodiment may be obtained and further, the strength of the display device may be increased by the addition of the protective plate 225 and the first electrode 221.
Referring to FIG. 32, the method for manufacturing the discharge vessels of the 8th to 14th embodiments will be described. First, a glass plate 310 of 6mm thick and a glass plate 212 of 3mm thick are prepared. As shown in FIG. 32(a), plurality of masks 314 are attached to a peripheral portion of the glass plate 310 and portions of the glass plate 310 on which to form spacers. Then, the glass plate 310 with the masks 314 is chemically etched as by hydrofluoric acid for predetermined time. Thereupon, as shown in FIG. 32(b), the glass member 210 is formed having the glass flat portion 213, the glass sealing portion 214 and the glass support members 215 serving as spacers, which are used in the 8th to 14th embodiments. As shown in FIG. 32(c), apart from the process by hydrofluoric acid, the fluorescent layer 216 is formed on the glass palte 212 as by silk printing. The fluorecent layer 216 is formed on regions of the glass plate 212 except the portions of the glass plate 212 which contact the glass sealing portion 214 and the glass support members 215 when the glass plate 212 and the glass member 210 are combined in the subsequent process to form a discharge vessel. Then, as shown in FIG. 32(d), a low-melting glass member 320 is applied to the border between the glass sealing portion 214 and the glass plate 212, thereby combining the glass member 210 and the glass plate 212, to form a discharge vessel 318. The discharge vessel 318 is evacuated and is then filled, for example, with xenon gas at a predetermined pressure.
To form the internal electrode 230, 230A of the 9th, 10th and 12th embodiment, the discharge vessel 318 of FIG. 32(d) is formed and the internal electrode 230 is inserted into the discharge vessle 318 through a predetermined point thereof. Alternatively, the glass member 210 of FIG. 32(b) is formed and the glass tubes 232, 232A of the 9th, 10th and 12th embodiments is attached to the glass member 210 so as to provided the internal electrode 230 or 230A. To form the opaque electrode 220 of the 8th, 9th and 11th embodiments on the inner surface of the glass flat portion 213, the discharge vessel 318 of FIG. 32(d) is formed, and carbon paint is applied to the outer surface of the glass flat portion 213. To form the opaque electrode 222 of the eighth embodiment on the glass plate 212, the electrode 222 is formed before the fluorescent layer 216 is formed on the glass plate 212. Further, the electrically conductive liquids 223, 221, the sealing members 226, 227 and the protective plates 224, 225 of the 11th to 14th embodiments may be formed after the discharge vessel 318 of FIG. 32(d) has been formed. Thus, various methods may be employed to form electrodes. It is to be noted that the fluorescent layer 216 may be formed on the inner surface of the glass flat portion 213. In this case, the fluorescent layer 216 may be formed after the glass member 210 of FIG. 32(d) has been formed.
When the above-mentioned method is employed for manufacturing the discharge vessel 318, the glass support members 215 and the glass sealing portion 214 having the same height may be precisely formed, so that when the discharge vessel is evacuated, the internal stress of the glass plate 212 and the glass flat portion 213 may be mitigated. Therefore, during manufacture, any possible damage to the discharge vessels may be prevented, thereby making it possible to manufacture large-sized discharge lamp type display devices. In addition, by suitably selecting the thickness and etching time of the glass plate 210, the distance H (FIG. 32(d)) may be freely determined between the glass plate 212 and the glass flat portion 213. Thus, a desired discharge lamp type display device may be manufactured easily.
Referring now to FIGS. 33 to 35, means for activating the display device of the present invention will be described. FIG. 33 shows an electrical circuit which may be used to activate the display device according to any of the foregoing embodiments for luminous discharge thereof, but hereinafter the description will be given in relation to, for example, the display device of the first embodiment (now designated by the reference number 48). FIGS. 34 and 35 show the waveform of a pulse signal generated by a control signal generator 52 in FIG. 33. The pulse signal is adapted for controlling a high frequency voltage to be applied to the display device 48 of the invention. A power supply 50 is connected at one end thereof to an input terminal of the control signal generator 52 and to one end of a primary winding of a boosting transformer 54. The power supply 50 is also connected at the other end thereof to the other input terminal of the control signal generator 52 and to an emitter of a transistor 56. The transistor 56 has a collector connected to the other end of the primary winding of the boosting transformer 54 and a base connected through a resistance 58 to an output terminal of the control signal generator 52. The other ends of the power supply 50 and the control signal generator 52 and the emitter of the transistor 56 are grounded. The boosting transformer 54 has a secondary winding connected at one end thereof to the first electrode 20 of the display device 48. The other end of the secondary winding of the boosting transformer 54 is connected to the second electrode 22 and is grounded.
The control signal generator 52 is composed of a pulse signal generator and is adapted to supply a pulse signal as shown in FIGS. 34 and 35 through the resistance 58 to the base of the transistor 56. The pulse signal has a pulse width t and a frequency T₂ of 0.5 to 20 kHz, and in response to the frequency T₂, the transistor 56 is turned on and off. As the transistor 56 is thus switched over, the boosting transformer 54 boosts the voltage at the primary winding to sufficient magnitude to discharge and light up the display device 48, creating at the secondary winding thereof a high frequency voltage in the order of 300 V to 6 kV at the peak, which is applied across the first electrode 20 and the second electrode 22.
The electrical circuit thus constructed permits uniform luminous discharge of the display device 48, and in case both of the first and second electrodes 20 and 22 are transparent, uniform luminous output is obtainable from the surfaces of the first and second glass plates 10 and 12.
Another electrical circuit to activate the display device of the present invention for luminous discharge will be described with reference to FIGS. 36 to 38. This circuit may be employed to activate the display device having the internal electrode, but hereinafter the description will be given in relation to, for example, the display device of the second embodiment (now designated by the reference number 60). The first electrode 20 is connected to a grounded end of the boosting transformer 54 and the internal electrode 30 is connected to the other terminal of the boosting transformer 54. The arrangement are equal to that of the electrical circuit in FIG. 33, except the construction of a control signal generator 62. Like parts are given like reference numbers and any further description of the electrical circuit will be omitted.
The control signal generator 62 is composed of a pulse signal generator 64 and a sawtooth signal generator 66. The pulse signal generator 64 has two input terminals which are connected to input terminals 70 and 72 of the control signal generator 62, respectively, and the sawtooth signal generator 66 has tow input terminals which are also connected to the input terminals 70 and 72, respectively. Outputs of the pulse signal generator 64 and the sawtooth signal generator 66 are connected to output terminal 74 and 76 of the control signal generator 62. The pulse signal generator 64 is adapted to generate a pulse signal having a frequency T₂ of 0.5 to 20 kHz, as shown in FIG. 38(a), and the sawtooth signal generator 66 is adapted to generate a sawtooth signal having a frequency T₁ of about a fraction of 1 Hz to several Hz, as shown in FIG. 38(b). The waveforms of FIGS. 38(a) and 38(b) provides a control pulse signal shown in FIG. 38(c). The control pulse signal has its peak value varied in a sawtooth form and has a frequency T₁. The input terminals 70 and 72 are connected to the output terminal of the power supply 50. The output terminal 74 is connected to the base of the transistor 56 and the output terminal 76 is connected to the primary winding of the boosting transformer 54.
When the control pulse signal shown in FIG. 38(a) is supplied to the base of the transistor 56 and when the sawtooth signal shown in FIG. 38(b) is supplied to the boosting transformer 54, the transistor 56 repeats on-off action as represented by the control pulse signal of FIG. 38(c), and the high frequency voltage whose peak value changes in a sawtooth form is applied through the boosting transformer 54 to the internal electrode 30 of the display device 60. Therefore, a luminous distribution in which the luminance is varied periodically in response to the sawtooth peak value of the high frequency voltage is obtainable in the discharge space of the display device 60. FIG. 39 shows how the display appears with the high luminance portion gradually moving in the direction indicated by an arrow as time elapses. Such a periodical change of the luminance gives a dynamic display effect indicating, for example, a surf and a waterfall. The pattern of the fluorescent layer and the fluorescent material forming the pattern may be selected as desired, so that luminous discharge of th display device activated by the above circuit can provided a dynamic display with various ideas.
As shown in FIG. 40, in order to form a positive column over the substantially entire area of the discharge vessel, the length A mm of the internal electrode extending into the discharge space may preferably be determined by the size of the discharge space (L mm long by ℓ mm wide by H mm deep). For example, given that L is 100 mm and ℓ is 100 mm, and when H is about 0.2 mm, the length A of the internal electrode 30 may be about 100 mm; when H is about 1 mm, the length A may be about several tens mm; and when H is about 3 to 4 mm, the length A may be several mm.
FIG. 41 shows various types of pulse signals which can be transmitted from the pulse signal generator 64. FIG. 41(a) shows a pulse signal having a frequency of T₂ and a pulse width of t, FIG. 41(b) a pulse signal having a frequency of T₂ and a pulse width of t/2, and FIG. 41(c) a pulse signal having a frequency of T₂ and a pulse width of 2t. In case of the pulse signal shown in FIG. 41(b), the luminance is decreased in comparison with that of the pulse signal in FIG. 41(a) to save energy. On the other hand, in case of the pulse signal in FIG. 41(c), the luminance is increased in comparison with that of the pulse signal in FIG. 41(a).
FIG. 42 shows various types of sawtooth control signals which can be transmitted from the control signal generator 62. FIG. 42(a) shows a sawtooth control signal having a period of T₁, FIG. 42(b) a sawtooth control signal having a period of T₁/2, and FIG. 42(c) a sawtooth control signal having a period of 2T₁. In case of the sawtooth control signal in FIG. 42(b), the luminance distribution in the illumination region is continuously varied in a shorter period to provide a quicker luminance change of the dynamic display, while in case of the sawtooth control signal in FIG. 42(c), the luminance distribution in the illumination region is continuously varied in a longer period to provide a slower luminance change of the dynamic display.
The control signal transmitted from the control signal generator 62 is not limited to the sawtooth signal. For exaomple, as shown in FIG. 43, a triangular signal generator 78 may be employed to generate a control signal whose peak value is varied in a triangular waveform. FIG. 44(a) shows a pulse signal from the pulse signal generator 64, FIG. 44(b) a triangular signal from the triangular signal generator 78, and FIG. 44(c) a control signal having a period of T₃ generated from the control signal generator 62. Thus, the control signal generator 62 can generate various control signals, which may be used to achieve a dynamic display in which the luminance changes variously.
While the invention has been described with reference to preferred embodiments thereof, it may be understood that modifications or variations may be easily made without departing from the scope of this invention which is defined by the appended claims.

Claims

1. A discharge lamp type display device including a transparent glass plate and a transparent glass member having a flat portion parallel to the glass plate, a discharge space between said glass plate and glass member, xenon gas serving as a discharge material and enclosed in said discharge space, a fluorescent layer coated on a predetermined position on the inner surface of at least one of said glass plate and glass member and having a thickness of 0.01 to 1 mm, and dual electrode means provided spaced apart on said device.

2. A device according to claim 1 wherein the glass member is a second glass plate parallel to the first mentioned glass plate.

3. A device according to claim 1 wherein said glass member has a glass flat portion disposed parallel to said glass plate and inclduing a glass sealing portion formed along the periphery of said glass flat portion and bonded to said glass plate to form said discharge vessel, said glass sealing portion being made of the same glass as said glass flat portion and having a predetermined height, and a plurality of spacers disposed between said glass plate and said glass flat portion, said plurality of spacers being made of the same glass as said glass flat portion and formed to have the same height as said glass sealing portion.

4. A device according to claim 1, 2 or 3 wherein the fluorescent layer is printed on the inner surface of one of said glass plate and glass member and has a predetermined pattern.

5. A device according to any preceding claim wherein first and second electrodes are respectively formed on the outside of the glass plate and the outside of the glass member.

6. The display device as defined in claim 5 wherein said first electrode is formed of a first electrically conductive film, and wherein said second electrode is formed of a second electrically conductive film.

7. The display device as defined in claim 6 wherein at least one of said first and second electrically conductive films is transparent.

8. A device according to any one of claims 1 to 4 wherein one electrode is mounted on one end of said transparent plate and member combination and extends into said discharge space.

9. The display device as defined in claim 8 further comprising voltage impressing means for impressing to said one electrode a voltage having frequency of 0.5 to 20 kHz and varying peak values, and grounding means for grounding said one electrode.

10. The display device as defined in claim 9 wherein in use said peak values of output voltage of said voltage impressing means vary periodically, or vary to provide sawtooth waveforms.

11. A device according to claim 8, 9 or 10 wherein another electrode is formed on the outer surface of one of said glass plate and flat portion of the glass member.

12. A device according to any one of claims 1 to 4 or 8 to 10 wherein a protective plate is disposed over one of said glass plate and said flat portion of said glass member and defines a space therewith and an electrically conductive liquid is enclosed in said space and serves as an electrode.

13. A device according to claim 12 wherein the protective plate protects the glass plate and/or glass member.

14. The display device as defined in claim 12 or 13 wherein said protective plate is made of a transparent acrylic plate.

15. The display device as defined in claim 12, 13 or 14 wherein said electrically conductive liquid is an aqueous solution of sodium chloride or sodium hydroxide.

16. A device according to any one of claims 12 to 15 except when dependent on one of claims 8 to 11 wherein another electrode is formed on the surface of the other of said glass plate and flat portion.

17. The display device as defined in claim 11 or 16 wherein said other electrode is formed of a transparent electrically conductive film.

18. A method for manufacturing a discharge lamp type display device including a discharge vessel having a pair of transparent glass plates and a plurality of spacers provided in between said glass plates, a discharge gas enclosed in said discharge vessel, a fluorescent layer coated on a predetermined position of the inner surface of at least one of said glass plates, and at least one electrode formed on the interior or the exterior of said discharge vessle, comprising the steps of;
preparing a first and a second glass plate;
attaching masks on one surface of said first glass plate at the periphery thereof and at the portions where said spacers are formed;
chemically etching said first glass plate to a predetermined depth;
combining and sealing said first and second glass plates to form said discharge vessel having said spacers;
evacuating said discharge vessel; and
filling said discharge vessel with a discharge gas at a predetermined pressure.