JPH1092589A - Inverter circuit for hot-cathode fluorescent lamp lighting device, and hot-cathode fluorescent lamp lighting device using this inverter circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot-cathode fluorescent lamp lighting device, which can maintain the same power consumption with the conventional case and which can improve the luminance of a fluorescent lamp without generating luminance grade in the fluorescent lamp and which can reduce the noise from wiring of the fluorescent lamp in the case of connecting two fluorescent lamps in series to each other, and its inverter circuit. SOLUTION: In an inverter circuit 2' for converting the direct current power source voltage of a hot-cathode fluorescent lamp lighting device to the alternating current voltage at a predetermined frequency and for applying the alternating current voltage to a fluorescent lamp 1, high-voltage transformers T1, T2 for discharge of lamp are connected in series to each other, and voltage output of one of the two high-voltage transformers T1, T2 is taken out as an opposite phase to the voltage output of the other transformer, and applied to the fluorescent lamp 1. Furthermore, capacitors Cb1, Cb2 having the nearly same capacity are interposed between an output side of each transformer of the inverter circuit 2' and electrodes of the hot-cathode fluorescent lamp 1 so as to discharge the hot-cathode fluorescent lamp 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for a hot cathode fluorescent tube used for a backlight of a large-screen liquid crystal display or the like, and more particularly to a lighting device in which the luminance efficiency of the fluorescent tube is increased and noise emission is reduced. Related to the device.

[0002]

2. Description of the Related Art Conventionally, since a hot cathode fluorescent tube can obtain higher brightness than a cold cathode tube, it is used for backlight illumination of a large-screen liquid crystal display and a light table for film inspection. Suitable.

The principle of light emission of a hot cathode fluorescent tube is as follows.
A voltage is applied to the filament electrode by a heater circuit to heat it. Then, thermoelectrons are emitted from the electron-emitting substance applied to the filament, and the temperature in the tube rises. With this temperature rise, the gas pressure of the mercury vapor sealed in the tube rises.

At this time, due to the electric field applied to the hot cathode fluorescent tube, the ionization of the mercury vapor gas in the vicinity of the filament proceeds, and a discharge (conduction state) in the tube is started. Due to this discharge, ultraviolet rays are emitted from the mercury vapor, and the ultraviolet rays excite phosphors coated in the tube to cause light emission.

FIGS. 2 to 5 show a basic circuit of a conventional hot cathode fluorescent tube lighting device. FIG. 2 is a configuration diagram showing an electric circuit of a lighting device for one hot cathode fluorescent tube, and FIG. 3 is a configuration diagram showing an electric circuit of a lighting device when two hot cathode fluorescent tubes are connected in parallel. 4 is a configuration diagram showing an electric circuit of a lighting device when two hot cathode fluorescent tubes are connected in series, and FIG. 5 is for a high power lamp using two high voltage transformers in parallel and an output winding in series. FIG. 3 is a configuration diagram showing an electric circuit of the lighting device of FIG.

2 to 5, reference numeral 1 denotes a hot cathode fluorescent tube (hereinafter referred to as a fluorescent tube); PS, a DC power supply for lighting the fluorescent tube 1; and GND, a ground terminal thereof. Reference numeral 2 denotes an inverter circuit for converting a DC voltage of the power supply PS into an AC voltage having a predetermined frequency, applying a high voltage to the tube, and lighting the tube. Reference numeral 3 denotes a heater circuit, 4 denotes a current detection circuit, 5 denotes a timer circuit, 6 denotes a switch circuit, and 7 denotes a PWM control circuit.

[0007] The inverter circuit 2 comprises a transformer T1 and an oscillating unit provided at a stage preceding the transformer T1. As can be understood from the portions shown by thick lines in FIGS. 2 to 5,
In any of the conventional methods, one electrode of a fluorescent tube to which a high voltage is applied from a transformer is connected to ground.

Further, as schematically shown in FIGS. 6 and 7, the wiring of the fluorescent tube 1 is formed by a reflector (metal) of a backlight.
And has a floating capacitance between these metal members and the fluorescent tube 1 and the wiring of the fluorescent tube 1. Heater wiring is to supply current to the filament,
Since two wires are protruded from each electrode, the stray capacitance of this wiring does not become ridiculous.

Further, since the fluorescent tube 1 has a larger shape than the cold cathode fluorescent tube, the length of the wiring is increased and the floating capacitance is increased. Further, since the high voltage output from the transformer is an alternating current, the alternating current component leaks to the housing or the reflection plate through the stray capacitance to cause a loss, and the current flowing through the fluorescent tube 1 is reduced by that amount, so that the fluorescent tube is reduced. The brightness of No. 1 decreases. In addition, since the fluorescent tube itself has a stray capacitance between itself and the housing, part of the current that should flow through the fluorescent tube leaks, and the luminance is high, such as the high voltage side of the fluorescent tube is bright and the ground side is dark. The slope comes out. Especially,
When the luminance is reduced, the inclination of the lamp surface luminance tends to be remarkable.

In the conventional example, when two fluorescent tubes are used in series, a transformer having a large output voltage is required. In this case, the noise from the fluorescent tube wiring is further increased. is there.

[0011]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to improve the brightness of a fluorescent tube while maintaining the same power consumption as in the conventional case, and to reduce the brightness gradient of the fluorescent tube. It is an object of the present invention to provide a hot-cathode fluorescent tube lighting device that does not occur and its inverter circuit.

It is still another object of the present invention to provide a hot cathode fluorescent tube lighting device capable of minimizing noise from the tube wiring when two hot cathode fluorescent tubes are connected in series, and an inverter circuit therefor.

[0013]

In order to achieve the above object, according to the present invention, a DC power supply voltage of a hot cathode fluorescent tube lighting device is converted into an AC voltage of a predetermined frequency, and the AC voltage is converted to a predetermined frequency. An inverter circuit applied to a hot cathode fluorescent tube, wherein two high-voltage transformers for tube discharge are connected in series,
We propose an inverter circuit of a hot cathode fluorescent tube lighting device that takes out the voltage output of one high-voltage transformer as the opposite phase of the voltage output of the other high-voltage transformer.

According to the inverter circuit, since the fluorescent tube is connected between the output terminal of the positive-phase transformer and the output terminal of the reverse phase, the fluorescent tube is lit from the ground potential in a floating state. And the stray capacitance between the wiring of the fluorescent tube and the housing or the reflector is reduced. Therefore, the leak current is reduced, the luminance of the fluorescent tube can be prevented from lowering, and the deviation of the luminance distribution is improved.

According to a second aspect of the present invention, there is provided an inverter circuit for converting a DC power supply voltage of a hot cathode fluorescent tube lighting device into an AC voltage having a predetermined frequency and applying the AC voltage to the hot cathode fluorescent tube. A plurality of high-voltage transformers are connected in series to form a set of two high-voltage transformers and connected in parallel, and the voltage output of one high-voltage transformer of each of the plurality of provided transformer sets is set to the opposite phase of the voltage output of the other high-voltage transformer. The present invention proposes an inverter circuit of a hot cathode fluorescent tube lighting device in which both sides are taken out together.

According to the inverter circuit, since the fluorescent tube is connected between the output terminal of the positive-phase transformer and the output terminal of the reverse phase, the fluorescent tube is lit from the ground potential in a floating state. And the stray capacitance between the wiring of the fluorescent tube and the housing or the reflector is reduced. Therefore, a leak current is reduced, and a decrease in luminance of the fluorescent tube can be prevented.
Further, since the transformers are connected in parallel, it is possible to cope with high power.

In a third aspect of the present invention, there is provided an inverter circuit for converting a direct current into an alternating current, and a heat source for lighting the hot cathode fluorescent tube by applying an output voltage of the inverter circuit to electrodes at both ends of the hot cathode fluorescent tube. In the cathode fluorescent tube lighting device, two high-voltage transformers for tube discharge are provided in series at the output of the inverter circuit, and the voltage output of one high-voltage transformer is set as the opposite phase of the voltage output of the other high-voltage transformer. At the same time, a lighting device for a hot cathode fluorescent tube is proposed in which a current limiting element having substantially the same capacitance value is interposed between the transformer output of the inverter circuit and the hot cathode fluorescent tube electrode to discharge the hot cathode fluorescent tube. I do.

According to the hot cathode fluorescent tube lighting device, the fluorescent tube is connected between the output terminal of the positive phase transformer and the output terminal of the opposite phase, so that the fluorescent tube floats from the ground potential. In this state, the stray capacitance between the wiring of the fluorescent tube and the housing or the reflection plate is reduced. Therefore, a leak current is reduced, and a decrease in luminance of the fluorescent tube can be prevented.

In a preferred embodiment of the present invention, there is provided an inverter circuit for converting a direct current to an alternating current, and a heat source for lighting the hot cathode fluorescent tube by applying an output voltage of the inverter circuit to electrodes at both ends of the hot cathode fluorescent tube. In the cathode fluorescent tube lighting device, a plurality of high-voltage transformers for tube discharge are connected in series at the output of the inverter circuit, and two or more high-voltage transformers are connected in series and connected in parallel. The voltage output of the high-voltage transformer is taken out together as an opposite phase of the voltage output of the other high-voltage transformer on each side, and the capacitance value between each output of the inverter circuit and the hot cathode fluorescent tube electrode is almost equal. The present invention proposes a lighting device for a hot cathode fluorescent tube that discharges the hot cathode fluorescent tube via a flow element.

According to the hot cathode fluorescent tube lighting device, the fluorescent tube is connected between the output terminal of the positive phase transformer and the output terminal of the opposite phase, so that the fluorescent tube is in a floating state from the ground potential. , And the stray capacitance between the wiring of the fluorescent tube and the housing or the reflection plate is reduced. Therefore,
Leakage current is reduced, and a decrease in luminance of the fluorescent tube can be prevented. Further, since the transformers are connected in parallel, it is possible to cope with high power. Furthermore, since a current-limiting element having substantially the same capacitance value is inserted between the end of the hot cathode fluorescent tube and the output of the transformer, the voltage at both ends of the fluorescent tube with respect to the ground potential (ground) becomes substantially equal, and the fluorescent tube Does not incline over the entire tube and becomes almost uniform.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an electric circuit according to the first embodiment of the present invention. In the figure, the same components as those in the above-described conventional example are denoted by the same reference numerals (excluding the transformer). The first embodiment is a circuit diagram when two fluorescent tubes 1 are connected in series.

In the figure, reference numeral 2 'denotes an inverter circuit (high voltage circuit) of the present invention, which has an inductance L1, a resistance R1, and a resistance R1.
2, an oscillating section composed of a Loyer circuit composed of transistors Q2, Q3 and a capacitor Cr, and transformers T1, T2 connected to the oscillating section.

The oscillating unit receives the power supply voltage PS (DC voltage) and allows an AC current having a predetermined frequency to flow through the primary windings of the transformers T1 and T2. The secondary windings of the transformers T1 and T2 convert an AC current flowing through the primary winding into an AC voltage (high voltage). Inverter circuit 2 'of the present invention
Operates using a low-voltage DC power supply PS in which commercial power is converted to DC by an AC / DC converter as a power supply. In other words, the inverter circuit 2 'of the present invention is a DC / AC inverter that converts a DC voltage to an AC voltage.

Reference numeral 1 denotes a hot cathode fluorescent tube (hereinafter, referred to as a fluorescent tube), and Cb1 and Cb2 denote balanced capacitors as current limiting elements to be described later. 3 is a heater circuit for heating the filament, which has an inductance L2 and a resistor R
4, R5, transistors Q4, Q5, capacitor Chr
And a transformer T3 connected to the oscillation unit.
Consists of 4 is a current detection circuit, and a diode D
2, a capacitor C1 and a resistor R3. 4 is a current detection circuit, 5 is a timer circuit, 6 is a switch circuit, 7
Is a PWM control circuit.

Next, the operation of this embodiment having the above-described configuration will be described. First, when the lighting switch SW1 is turned on, the heater circuit 3 operates via the timer circuit 5 and the switch circuit 6. The timer circuit 5 includes the fluorescent tube 1
Is used to cause the discharge of the heater after the heater is preheated.
It is activated as soon as W1 is turned on.

When a predetermined time (1-2 seconds) elapses after the lighting switch SW1 is turned on, the operation of the timer circuit 5 activates the inverter circuit 2 '.

The operation of the inverter circuit 2 'is as follows. First, the DC power supply PS is input to the PWM control circuit 7 via the switching element Q1, and operates via the diode D1.

The characteristic of the Loyer circuit used in the inverter circuit 2 'is that a feedback circuit is provided in a transformer (transformer) to perform positive feedback from the collector of each transistor to the base, thereby automatically performing an on / off operation. Is a so-called self-excited oscillator. R1 and R2 are bias resistors that pre-apply a forward voltage to the base in order to facilitate starting, and have essentially no effect on operation.

When the timer circuit 5 operates, the transistors Q2 and Q3 alternately turn on and off, a high-frequency current flows through the primary windings of the transformers T1 and T2, and a high-frequency voltage appears on the secondary windings. The frequency of this AC voltage is
It is determined by the switching frequency of the transistors Q2 and Q3. As is well known, the boosting degree of the secondary voltage of the transformers T1 and T2 is determined by the ratio of the number of turns of the primary winding and the secondary winding.

When the Royal circuit oscillates, the transistor Q
2 and Q3 show the collector voltage waveforms in FIGS.
become that way. Then, since the outputs (phases) of the transformers T1 and T2 appear 180 degrees apart, the output voltage waveform of the transformer T2 appears in an inverted form of the output voltage waveform of the transformer T1 ((c) and (d) in FIG. 8). .

By the outputs of the two transformers, the electrodes f1 of the one fluorescent tube 1 and the electrode f4 of the other fluorescent tube are driven with mutually opposite voltages as shown in FIGS. 8 (e) and 8 (f). . The outputs of the transformers T1 and T2 are
To supply a constant current to the balanced capacitors Cb1 and Cb1
The voltage is applied to the fluorescent tube through a current limiting element such as b2.

When the outputs of the transformers T1 and T2 are viewed in terms of amplitude, both of the transformers T1 and T2 are the same as the output of one transformer. However, since the phases of the two are inverted, the output of one of the transformers T1 and T2 is referred to. Then, a voltage as shown in (h) of FIG. 8 is apparently applied to the fluorescent tube 1. Looking at this in terms of amplitude (maximum value), transformer 2
It can be understood that the output for each item is taken out.

Further, the voltages of the electrodes f2 and f3 of the fluorescent tube 1 become substantially zero volts because they are at the midpoints of voltages having opposite phases (FIG. 8 (g)). Therefore, as shown in FIG. 9, the brightness does not tilt at both ends of the fluorescent tube, and almost uniform brightness can be obtained when viewed through the entire fluorescent tube (FIG. 10).

Further, since the phases of the voltages at both ends of the fluorescent tube are opposite to each other, noises emitted from the wiring cancel each other out and are reduced. Accordingly, it is possible to provide a lighting device and an inverter circuit thereof with less noise than in the case of single lamp discharge while discharging the fluorescent tube 1 in which two lamps are connected in series.

The connection from the secondary side coils of the transformers T1 and T2 to the PWM control circuit 7 through the current detection circuit 4 is based on this feedback system.
This is for controlling the voltage applied to both the fluorescent tubes 1 so that the tube current becomes constant. That is, the resistor R3
Is for converting a current into a voltage, and a diode D
2 rectifies it half-wave and capacitor C1 holds the peak voltage. And the PWM control circuit 7
By detecting the transmitted peak voltage value, the inverter circuit 2 ′ adjusts the voltage value applied to the fluorescent tube 1. Further, the PWM control circuit 7 controls the voltage value applied to the inverter circuit 2 ′ by operating a separately provided dimming switch (SW 2) to adjust the brightness of the fluorescent tube 1.

Next, a second embodiment of the present invention will be described. FIG. 11 is a configuration diagram showing an electric circuit according to the second embodiment of the present invention. In the drawing, the same components as those of the above-described conventional example and the first embodiment are denoted by the same reference numerals (however, excluding the transformer). In the second embodiment, two fluorescent tubes 1 are connected in parallel.

Also in the case of the second embodiment, the transformers T1 and T2 have different output polarities in the secondary winding.
The output voltage waveforms of the transformers T1 and T2 have a phase of 180
Different. The outputs of the transformers T1 and T2 are applied to both electrodes of the fluorescent tube 1 through balanced capacitors Cb1 / Cb3 and Cb2 / Cb4, respectively.

The electrodes f1 and f2 of the fluorescent tube 1 and f3 and f
4 are driven by applying voltages having opposite phases to each other. Also in the present embodiment, since both electrodes of the fluorescent tube 1 are not grounded, the brightness does not tilt at both ends of the fluorescent tube as shown in FIG. 9, and as shown in FIG. Uniform brightness can be obtained.

Next, a third embodiment of the present invention will be described. FIG. 12 is a configuration diagram showing an electric circuit according to the third embodiment of the present invention. In the figure, the same components as those of the above-described conventional example and the first and second embodiments are denoted by the same reference numerals (except for the transformer).

The third embodiment shows an example in which four transformers are added for a high-power fluorescent tube. Especially,
When used as a low-profile backlight in a display device of a portable device such as a notebook computer, power must be supplied by using a plurality of small transformers. In this embodiment, the transformers T3 and T4 are connected in parallel with the transformers T1 and T2, and the outputs of the transformers T1 and T3 are output in the positive phase, and the outputs of the transformers T2 and T4 are output in the opposite phase.

Therefore, even when the transformers T1 to T4 are each of a low power type, as in the present configuration, a set of a transformer outputting in the normal phase and a transformer outputting in the opposite phase are connected in a plurality of stages in parallel. By outputting the outputs for each phase together, a large power configuration can be achieved. Other functions and effects are the same as those of the first embodiment.

[0042]

As described above, according to the first aspect of the present invention,
According to the inverter circuit described above, a transformer in which two high-voltage transformers for tube discharge are connected in series is provided, and the output of one high-voltage transformer is taken out in the opposite phase to the output of the other high-voltage transformer. Since the tube is lit in a floating state from the ground potential, the stray capacitance between the wiring of the hot cathode fluorescent tube and the housing or the reflector can be reduced. Thereby, a leak current is reduced, and a decrease in luminance of the hot cathode fluorescent tube can be prevented. In particular, when the brightness of the hot cathode fluorescent tube is adjusted to be low, the bias of the brightness distribution such that the high voltage side becomes bright and the low voltage side becomes dark is improved.
Furthermore, the output voltage per high-voltage transformer can be reduced, and unnecessary radiation (noise) can be reduced.

According to the inverter circuit of the present invention, a plurality of transformers in which two high voltage transformers for tube discharge are connected in series are provided, these are connected in parallel, and the output of one high voltage transformer is connected to the other high voltage transformer. Since the output is taken out of phase with the transformer output, the hot-cathode fluorescent tube lights up in a floating state from the ground potential, and the stray capacitance between the wiring of the hot-cathode fluorescent tube and the housing or reflector can be reduced. it can. Thereby, a leak current is reduced, and a decrease in luminance of the hot cathode fluorescent tube can be prevented. In particular, when the brightness of the hot cathode fluorescent tube is adjusted to be low, the bias of the brightness distribution such that the high voltage side becomes bright and the low voltage side becomes dark is improved. Furthermore, while being able to cope with high power,
The output voltage per high-voltage transformer can be reduced, and unnecessary radiation (noise) can be reduced.

According to a third aspect of the present invention, there is provided a lighting device for a hot cathode fluorescent tube, wherein two high voltage transformers for tube discharge are connected in series, and the output of one high voltage transformer is changed to the output of the other high voltage transformer. The hot cathode fluorescent tubes are turned on in a floating state from the ground potential, and the stray capacitance between the wiring of the hot cathode fluorescent tubes and the housing or reflector can be reduced. Thereby, a leak current is reduced, and a decrease in luminance of the hot cathode fluorescent tube can be prevented. In particular, when the brightness of the hot cathode fluorescent tube is adjusted to be low, the bias of the brightness distribution such that the high voltage side becomes bright and the low voltage side becomes dark is improved. Furthermore, the output voltage per high-voltage transformer can be reduced, and unnecessary radiation (noise) can be reduced. Furthermore, since a current limiting element having substantially the same capacitance value is interposed between the hot cathode fluorescent tube electrode and the transformer output, the voltage at both ends of the fluorescent tube with respect to the ground potential is almost equal in balance, and the brightness of the fluorescent tube Does not incline over the entire fluorescent tube, and the luminance can be made substantially uniform. When two fluorescent tubes are connected in series, noise from the wiring of the fluorescent tubes can be reduced as much as possible.

Further, according to the hot cathode fluorescent tube lighting device of the fourth aspect, a plurality of transformers in which two high voltage transformers for tube discharge are connected in series are provided, these are connected in parallel, and one of the high voltage transformers is connected. Since the output is taken out of phase with the output of the other high-voltage transformer, the hot-cathode fluorescent tube lights up in a floating state from the ground potential, and the stray capacitance between the wiring of the hot-cathode fluorescent tube and the housing or reflector plate Can be reduced. Thereby, a leak current is reduced, and a decrease in luminance of the hot cathode fluorescent tube can be prevented. In particular, when the brightness of the hot cathode fluorescent tube is adjusted to be low, the bias of the brightness distribution such that the high voltage side becomes bright and the low voltage side becomes dark is improved. Further, it is possible to cope with high power, and the output voltage per one high-voltage transformer can be reduced, so that unnecessary radiation (noise) can be reduced.
Furthermore, since a current limiting element having substantially the same capacitance value is interposed between the hot cathode fluorescent tube electrode and the transformer output, the voltage at both ends of the fluorescent tube with respect to the ground potential is almost equal in balance, and the brightness of the fluorescent tube Does not incline over the entire fluorescent tube, and the luminance can be made substantially uniform. Also,
When two fluorescent tubes are connected in series, noise from the wiring of the tubes can be minimized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an electric circuit according to a first embodiment of the present invention;

FIG. 2 is a configuration diagram showing an electric circuit of a conventional lighting device for one hot cathode fluorescent tube.

FIG. 3 is a configuration diagram showing an electric system circuit of a lighting device in which two conventional hot cathode fluorescent tubes are connected in parallel.

FIG. 4 is a configuration diagram showing an electric circuit of a lighting device in which two conventional hot cathode fluorescent tubes are connected in series.

FIG. 5 is a configuration diagram showing an electric circuit of a high-power hot-cathode fluorescent tube lighting device in which two conventional high-voltage transformers are used and output windings are connected in series.

FIG. 6 is a diagram illustrating a fluorescent tube and a lead wire in an edge light type backlight.

FIG. 7 shows a fluorescent tube in a direct backlight system,
Diagram for explaining the state of lead wire and reflector

FIG. 8 is a signal waveform diagram according to the first embodiment of the present invention.

FIG. 9 is a view for explaining the luminance distribution of a conventional fluorescent tube.

FIG. 10 is a diagram illustrating a luminance distribution of a fluorescent tube according to an embodiment of the present invention.

FIG. 11 is a configuration diagram showing an electric circuit according to a second embodiment of the present invention.

FIG. 12 is a configuration diagram showing an electric circuit according to a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hot cathode fluorescent tube, 2 ... Inverter circuit of conventional hot cathode fluorescent tube lighting device, 2 '... Inverter circuit of hot cathode fluorescent tube lighting device of the present invention, 3 ... Heater circuit, 4 ... Current detection circuit, 5 ... Timer circuit, 6 ... Switch circuit, 7 ... P
WM control circuit, f1 to f4 ... filament, T
1 to T5 ... Transformer.

Claims (4)

[Claims] 1. An inverter circuit for converting a DC power supply voltage of a hot cathode fluorescent tube lighting device into an AC voltage having a predetermined frequency and applying the AC voltage to the hot cathode fluorescent tube. An inverter circuit for a hot cathode fluorescent tube lighting device, wherein two inverters are connected in series, and a voltage output of one high voltage transformer is taken out as an opposite phase of a voltage output of the other high voltage transformer. 2. An inverter circuit for converting a DC power supply voltage of a hot cathode fluorescent tube lighting device into an AC voltage having a predetermined frequency and applying the AC voltage to the hot cathode fluorescent tube. A plurality of series-connected transformers are provided in parallel and connected in parallel, and the voltage output of one high-voltage transformer of each of the plurality of provided transformer sets is set as the opposite phase of the voltage output of the other high-voltage transformer, and An inverter circuit for a hot cathode fluorescent tube lighting device, wherein the inverter circuit is also taken out. 3. A hot-cathode fluorescent lamp which is provided with an inverter circuit for converting a direct current to an alternating current, and which lights the hot-cathode fluorescent tube by applying an output voltage of the inverter circuit to electrodes at both ends of the hot-cathode fluorescent tube. In the apparatus, two high-voltage transformers for tube discharge are provided in series at an output part of the inverter circuit, and a voltage output of one high-voltage transformer is taken out as an opposite phase of a voltage output of the other high-voltage transformer, and the inverter is provided. A lighting device for a hot cathode fluorescent tube, wherein a current limiting element having substantially the same capacitance value is interposed between a transformer output of a circuit and a hot cathode fluorescent tube electrode to discharge the hot cathode fluorescent tube. 4. A hot-cathode fluorescent lamp which is provided with an inverter circuit for converting a direct current to an alternating current, and which lights the hot-cathode fluorescent tube by applying an output voltage of the inverter circuit to electrodes at both ends of the hot-cathode fluorescent tube. In the apparatus, a plurality of transformers in which two high-voltage transformers for tube discharge are connected in series in a set at an output portion of the inverter circuit are connected in parallel, and a voltage of one high-voltage transformer of each of the plurality of provided transformer sets is provided. The outputs are taken out together on each side as the opposite phase of the voltage output of the other high-voltage transformer, and a current limiting element having substantially the same capacitance value is interposed between each output of the inverter circuit and the hot cathode fluorescent tube electrode. A lighting device for a hot cathode fluorescent tube, characterized in that the hot cathode fluorescent tube is discharged by discharging.