JPH09283287A - Lighting device for indication discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such a lighting device for an indication discharge lamp as being capable of ensuring opening/closing control of a switching means in a simple structure and lighting control of the indication discharge lamp, even if stray capacitance exists in the switching means. SOLUTION: A lighting device has a lighting means 1 to generate high frequency high voltage, an indication discharge lamp B provided with a luminous layer on the inner face and at least one electrode B6 out of electrodes B5, B6 on the outer face of an enclosure filled with rare gas in an inside space, the first capacitor 3 connected in parallel to the indication discharge lamp and a switching means 2 provided with a control terminal to be open/closed in accordance with a control signal granted to the terminal. The lighting means 1, the indication discharge lamp and the switching means are connected together in series and the capacity of the first capacitor is set for voltage distributed to the first capacitor in relation to the stray capacitance of the switching means, when open, to be lower than voltage enough to keep lighting for the indication discharge lamp, so that light-on/light-off control of the indication discharge lamp are ensured.

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 display discharge lamp, and more particularly to an improvement of a lighting device for a display discharge lamp used as a display element in a large color display device or the like.

[0002]

2. Description of the Related Art Conventionally, this type of display discharge lamp is constructed, for example, as shown in FIG. 6 (Japanese Patent Laid-Open No. 5-19015).
No. 2). In the figure, A1 is a cylindrical envelope made of, for example, glass, and a light emitting layer A2 that emits light in any one of a blue region, a green region, and a red region is formed on a cylindrical portion of its inner surface. Has been done. This envelope A1
A first sealing portion A3 is formed at one end portion and a second sealing portion A4 is formed at the other end portion, and in particular, the first sealing portion A3 is transparent. ing. A rod-shaped internal electrode A5 having a length substantially equal to that of the light emitting layer A2 is arranged in the central portion inside the envelope A1.
On the outer peripheral surface excluding the sealing portion A3, the external electrode A6 is arranged in the same area as the formation area of the light emitting layer A2. Further, an appropriate rare gas such as xenon, krypton, argon, neon, or helium is contained in the inner space of the envelope A1.
It is enclosed at an enclosure pressure of 0 to 200 torr.

This display discharge lamp A has tens of thousands and hundreds of thousands arranged in a line in a display board such as a baseball field and an advertising tower, and an AC power supply PS is provided between an internal electrode A5 and an external electrode A6. A discharge is generated by connecting. As a result, the emitted light from the light emitting layer A2 is emitted to the outside through the transparent first sealing portion A3. Therefore, the blue region,
A plurality of display discharge lamps A that emit light in the green region and the red region are regarded as one unit, and a desired display can be realized by selectively discharging each of the display discharge lamps A according to the contents of the display. Not only is this possible, but also the cost can be reduced because the structure of the display discharge lamp is simplified.

However, in this display discharge lamp A,
Although the light emitted from the first sealing portion A3 in the direction of the arrow in the drawing (the direction perpendicular to the surface of the sealing portion A3) has high brightness, it is not in the direction perpendicular to the surface of the sealing portion A3. The luminance in the direction of is greatly reduced as the angle becomes smaller. Therefore, although the image quality of the display screen is kept high when the display surface is viewed only from the right angle direction, the display screen is dark and the image quality is significantly impaired when viewed from a direction other than the right angle direction. Therefore, when the display surface is viewed from various angles such as in a baseball field or an advertising tower, there is a problem in that the image quality of the display surface is good or bad depending on the viewing direction.

[0005]

Therefore, the applicant of the present invention is
First, the display discharge lamp B shown in FIGS. 7 to 8 was proposed. In the figure, B1 is an envelope, such as lead glass,
It is made of boro / silicate glass, soda glass, ceramics, etc. in a tubular shape. At one end of the envelope B1, there is provided a substantially transparent first sealing portion B2 made of a material such as lead glass, boro-silicate glass, soda glass, or ceramics and having a light transmitting property. It is hermetically sealed,
The light emitting layer B3 is formed on the entire inner surface by a single phosphor that emits light in, for example, a blue region, a green region, and a red region. The light emitting layer B3 can also be formed by mixing a plurality of phosphors depending on the application. Also, the envelope B1
A second sealing portion B4 made of a member such as lead glass or soda glass is hermetically sealed at the other end of the.

The second sealing portion B4 is composed of, for example, a stem mount composed of a stem and an exhaust pipe integrally formed with the stem, and the flare end edge portion of the stem is sealed in the envelope B1. It is worn. An internal electrode B5 made of a metal member such as nickel or tungsten is erected on the stem of the stem mount (B4), and one end of the internal electrode B5 is arranged near the light emitting layer B3 in the sealed state. ing. A lead wire for external lead-out is connected to the other end of the internal electrode B5 via a sealing metal or the like. In particular, noble gas, for example, 20 to 2 is contained in the inner space of the envelope B1.
It is enclosed in a 00-tool. Xenon is suitable as the rare gas, but krypton, helium, neon, and argon can be appropriately mixed with xenon, or can be used alone or appropriately instead of xenon.

Further, an outer electrode B6 made of a metal member having good conductivity is arranged, for example, in a ring shape on the outer peripheral surface portion of the envelope B1 near the first sealing portion B2. As the external electrode B6, for example, a metal member such as aluminum, nickel, or copper formed in a narrow band shape and having an adhesive layer having an adhesive or adhesive function on one surface is preferable. From the viewpoint of miniaturization and the like, an aluminum foil provided with an adhesive layer is preferable. On the other hand, in the space surrounded by the external electrode B6, the internal electrode B5
One of the ends is arranged so that the interval between the one end and each part of the external electrode B6 is not uniform.
The internal electrode B5 may be arranged so that the interval between the internal electrode B5 and the external electrode B6 is uniform.

The display discharge lamp B thus constructed is
For example, it is turned on by the lighting device shown in FIG. In the figure, 1 is a lighting means, for example, an inverter circuit for generating a high frequency high voltage having a frequency of 29 KHz and a voltage of about 500 V on the output side. A transistor TR as a switching means is connected to the input side of the inverter circuit 1, and a display discharge lamp B is connected to the output side thereof. Now, when a predetermined DC voltage is applied to the terminals T1 and T2 to close the transistor TR, a high frequency high voltage is generated on the output side of the inverter circuit 1 and the display discharge lamp B
The internal electrode B5 and the external electrode B6 are applied and lighted.
In this state, when a predetermined dimming signal according to the display content is given to the terminal Td, the transistor TR is opened / closed based on the signal, so that the brightness of the display discharge lamp B is appropriately dimmed. , A desired display screen is obtained.

Moreover, radiant light with high brightness is emitted from the light emitting layer B3 based on the discharge generated between the internal electrode B5 and the external electrode B6, but the first sealing portion 2 is substantially formed. In this case, the luminance in the direction perpendicular to the surface of the first sealing portion B2 can be made high as in the conventional example, and the luminance in directions other than the perpendicular direction is compared to the conventional example. It can be improved and the directivity is eased. Therefore, when it is applied to a large display device such as a baseball field or an advertising tower that is viewed and viewed from a wide angle, the quality of the image quality of the display surface depending on the viewing and viewing position is mitigated and maintained above a certain level. .

However, in this lighting device, one inverter circuit 1 is required for one display discharge lamp B, but normally the display device emits light in the blue, green, green and red regions. Show 1 of 4 display discharge lamps B
One pixel is configured as a unit, and the number of pixels is extremely large, such as tens of thousands and hundreds of thousands. For this reason, there is a problem that the number of inverter circuits increases and the equipment cost rises.

Therefore, in order to solve such a problem, a lighting device shown in FIG. 10 has been proposed. That is, this lighting device is configured by connecting the display discharge lamp B and the switching means 2 such as an FET (field effect transistor) in series to the output side of the inverter circuit 1. According to this lighting device, even if a plurality of series circuits of the display discharge lamp B and the switching means 2 are connected in parallel on the output side of the inverter circuit 1, each display discharge lamp B is connected.
With the switching means 2, it is possible to control lighting independently without affecting each series circuit.
For this reason, one inverter circuit may be provided for one pixel, and the number of inverter circuits is 1 / th of that of the lighting device shown in FIG.
The number can be reduced to 4, and an inexpensive display device can be realized.

However, in this lighting device, the output side of the inverter circuit 1 has a frequency of, for example, 29 KH.
When a field effect transistor (FET) having excellent withstand voltage and switching property is used for the switching means 2 because a high frequency and high voltage of z and a voltage of about 500 V are output, a voltage between the drain electrode and the source electrode is The stray capacitances C ₀ and C ₁ existing between the drain electrode and the gate electrode cannot be ignored at high frequencies, and the lighting control of the display discharge lamp B is seriously affected.

That is, in this lighting device, when a predetermined (high level) control signal is applied to the gate of the FET2, the FET2 is closed and the internal electrode B of the display discharge lamp B is closed.
5. By applying a high frequency high voltage to the external electrode B6, the display discharge lamp B is turned on. Next, when the control signal given to the gate of the FET2 is switched to the low level according to the displayed contents, the FET2 is opened and the display discharge lamp B is turned off. However, FE
Even if T2 is opened, the internal electrodes B5,
Since the high frequency high voltage is still applied to the external electrode B6 via the stray capacitance C ₀ between the drain electrode and the source electrode, the display discharge lamp B continues to be lit.
For this reason, it becomes impossible to control the turning off of the display discharge lamp B by the control signal applied to the gate, and the desired display cannot be displayed.

In addition, this FET 2 has a drain electrode and a gate.
Since the stray capacitance C ₁ is also present between the gate electrode and the display electrode, even if a low-level control signal is applied to the gate when the display discharge lamp B is turned on, the FET 2 is inverted to the open state. It may stop doing. That is, the gate has a stray capacitance C ₁
A high frequency high voltage is applied via the, and a current based on this is applied to the control signal system. If this current can be absorbed in the control signal system, the FET 2 can be surely opened / closed based on the control signal given to the gate. However, when the above floating current cannot be absorbed in the control signal system, the gate becomes high level,
Regardless of the control signal, FET2 will always be kept closed. Therefore, the display discharge lamp B continues to be turned on, and it becomes impossible to control the turning off of the display discharge lamp B by the control signal applied to the gate, so that the desired display cannot be displayed.

Therefore, an object of the present invention is to provide a display device that can reliably control the opening and closing of the switching device with a simple structure even when there is stray capacitance in the switching device, and can also reliably control the lighting of the display discharge lamp. It is to provide a lighting device for a discharge lamp.

[0016]

Therefore, in order to achieve the above-mentioned object, the present invention has a lighting means for generating a high frequency high voltage, a light emitting layer on the inner surface, and a rare gas sealed in the inner space. Of the plurality of electrodes on the outer surface of the envelope, a display discharge lamp having at least one electrode arranged therein, a first capacitor connected in parallel to the display discharge lamp, and a control terminal, A switching means that opens and closes based on a control signal applied to this terminal, the lighting means, the display discharge lamp, and the switching means are connected in series, and the capacitance of the first capacitor is changed to the switching means. The voltage distributed to the first capacitor is set to be lower than the lighting maintaining voltage of the display discharge lamp in relation to the stray capacitance of the switching means at the time of opening.

According to a second aspect of the present invention, the lighting means includes:
A third aspect of the invention is characterized in that the display discharge lamp comprises an inverter circuit that outputs a high frequency high voltage.
At least the light emitting layer is formed on the inner surface, and an envelope having a rare gas sealed in the inner space, an outer electrode arranged on the outer surface of the envelope, and an inner electrode arranged inside the envelope. The fourth invention is characterized in that a plurality of series circuits of a display discharge lamp and a switching means are connected in parallel on the output side of the lighting means.

Further, a fifth aspect of the present invention is to provide a lighting means for generating a high frequency high voltage, and an outer electrode on the outer surface of an envelope having a light emitting layer on the inner surface and containing a rare gas in the inner space. , A display discharge lamp in which internal electrodes are respectively arranged in the internal space, a first capacitor connected in parallel to the display discharge lamp, and a control terminal, based on a control signal given to this terminal. A plurality of series circuits of the display discharge lamp and the switching means are connected in parallel to the output side of the lighting means, and an external electrode of each display discharge lamp is common. Connected to, and first
The capacitance of the capacitor is set such that the voltage distributed to the first capacitor in relation to the stray capacitance of the switching means when the switching means is opened is lower than the lighting maintaining voltage of the display discharge lamp. To do.

Furthermore, a sixth aspect of the present invention is a pair of electrodes on the outer surface of an envelope having a lighting means for generating a high frequency high voltage, a light emitting layer on the inner surface, and a rare gas sealed in the inner space. Of the display discharge lamp having at least one of the electrodes, a first capacitor connected in parallel to the display discharge lamp, and a control terminal, and based on a control signal given to this terminal. And a switching means for opening and closing the switching means, the lighting means, the display discharge lamp, and the switching means are connected in series, and a second capacitor is connected to a control terminal of the switching means, and The capacitance is set so that the voltage distributed to the second capacitor in relation to the stray capacitance between the switching means and the control terminal when the switching means is opened is a voltage that does not cause the switching means to close. In the seventh invention, a plurality of series circuits of the display discharge lamp and the switching means are connected in parallel on the output side of the lighting means, and the second control terminals of the respective switching means are connected in parallel. It is characterized by connecting a capacitor.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a first embodiment of the present invention will be described with reference to FIGS. 7 to 10
Are given the same reference numerals as in the prior art shown in FIG.

In the figure, the characteristic part of this embodiment is that the first capacitor 3 is connected in parallel to the internal electrode B5 and the external electrode B6 of the display discharge lamp B, and the control terminal of the switching means 2. That is, the second capacitor 4 is connected to. Although a field effect transistor (FET) is suitable as the switching means 2, a transistor, a thyristor or the like can be used.

In particular, the capacitance of the first capacitor 3 is such that when the switching means 2 is opened, the voltage distributed to the first capacitor 3 in relation to the stray capacitance (C ₀ ) of the switching means 2 is discharged for display. It is set to be lower than the lighting maintaining voltage of the electric lamp B. For example, the first capacitor 3
It is desirable that the capacity of the first capacitor 3 is approximately the same as the stray capacity, but it may be necessary to make the capacity of the first capacitor 3 larger than the stray capacity depending on the lighting maintaining characteristics of the display discharge lamp B. In any case, when the display discharge lamp B is turned on, a current flows not only in the display discharge lamp B but also in the first capacitor 3, and the load current of the lighting means 1 increases, which is also a factor that increases the cost. Become. Therefore, it is desirable that the capacity of the first capacitor 3 is determined in consideration of the load current of the lighting means 1 not increasing more than necessary.

Specifically, the switching means 2 is F
When ET is used, the stray capacitance C ₀ between the drain electrode and the source electrode is about several tens of PFs (picofarads), although there are variations in the FET itself, so that the capacitance of the first capacitor 3 is reduced. The capacity is also set to several tens of PF, for example, about 40 PF.

The capacitance of the second capacitor 4 is the voltage distributed to the second capacitor 4 in relation to the stray capacitance (C ₁ ) between the switching means 2 and its control terminal when the switching means 2 is opened. Is set to be lower than the voltage required for closing the switching means 2. For example, the capacitance of the second capacitor 4 is preferably set to be 100 times or more the stray capacitance C ₁ , and according to this, the voltage distributed to the second capacitor 4 can be set to a predetermined voltage or less.

Specifically, F is used as the switching means 2.
When ET is used, the stray capacitance C ₁ between the drain electrode and the gate electrode is approximately several tens of PF, although there are variations in the FET itself, and therefore the capacitance of the second capacitor 4 is 0. It is set to about 01 to 0.1 μF.

On the other hand, in this lighting device, the gate electrode of the switching means 2 is connected to the control signal generating means 6 via the resistor 5. The control signal generating means 6 compares the sawtooth wave voltage and the dimming voltage Vd with the oscillator 61 for generating the sawtooth wave voltage shown in FIG. It is composed of a comparison unit 62 for generating the control signal shown in FIG. 9B and an amplification unit 63 for amplifying the control signal.

Next, the display discharge lamp B by this lighting device
The lighting operation of will be described. Now switching means 2
When the control signal shown in FIG. 3 (b) is applied to the gate electrode, the switching means 2 is closed.
When the switching means 2 is closed, a high frequency high voltage is applied from the lighting means 1 to the internal electrode B5 and the external electrode B6 of the display discharge lamp B, and the display discharge lamp B is lit. At this time, a current also flows through the first capacitor 3.

In this state, if the dimming voltage Vd applied to the dimming terminal Td is changed to the lower direction, FIG.
The width of the control signal shown in (1) becomes wider, the closing ratio of the switching means 2 becomes higher, and the brightness of the display discharge lamp B also becomes brighter. Then, when the voltage becomes lower than the minimum voltage of the sawtooth wave voltage, the control signal is continuously generated, and the switching means 2
Will always be closed, and the brightness of the display discharge lamp B will be 100% full light. On the contrary, when the dimming voltage Vd becomes high, the width of the control signal becomes narrow and the brightness becomes dark. And when it becomes higher than the maximum voltage of the sawtooth wave voltage,
The control signal is not generated, the switching means 2 is always in the open state, and the display discharge lamp B is in the off state.

The transition of the display discharge lamp B from the lighting state to the extinguishing state is achieved by the following operation. That is, when the application of the control signal to the gate electrode of the switching means 2 is stopped, the first capacitor 3 and the stray capacitance C ₀ (stray capacitance between the drain electrode and the source electrode) are turned on. The output voltage of the means 1 is distributed according to the respective capacitance ratio. In particular, since the first capacitor 3 is set to a capacitance that is approximately the same as the stray capacitance C ₀ , approximately half the output voltage of the lighting means 1 is applied to each. Since the discharge sustaining voltage of the display discharge lamp B is, for example, about 60% of the rated value, the distribution voltage to the display discharge lamp B becomes about 50%, which is lower than the discharge sustaining voltage, by the opening operation of the switching means 2. . Therefore, the display discharge lamp B is surely turned off.

On the other hand, during the opening operation of the switching means 2, a current flows through the stray capacitance C ₁ existing between the drain electrode and the gate electrode, but the second electrode connected to the gate electrode. It is made to flow to the ground side through the condenser 4 of. At this time, the capacitance of the second capacitor 4 is the stray capacitance C.
_{Since the} capacitance value is set to be significantly larger than ₁ , the voltage distributed to the second capacitor 4 becomes extremely low. Therefore, the switching means 2 is not inverted again to the closing operation by the distribution voltage to the second capacitor 4, and the opening / closing operation can be surely performed.

According to this embodiment, between the inner electrode B5 and the outer electrode B6 of the display discharge lamp B, the first capacitor 3 having the same capacitance as the stray capacitance C ₀ of the switching means 2 is provided. Since they are connected in parallel, when the switching means 2 shifts from the closed state to the open state, the first
The distribution voltage of the capacitor 3 becomes less than the discharge sustaining voltage of the display discharge lamp B. Therefore, the discharge of the display discharge lamp B can be surely stopped and the desired display can be performed.

Further, the gate electrode of the switching means 2 is connected to the second capacitor 4 having a capacitance value significantly larger than the stray capacitance C ₁ thereof, so that the switching means 2 is opened from the closed state. When reversing to the state, the voltage distributed to the second capacitor 4 becomes such a low voltage that the switching means 2 cannot be closed. Therefore, when a control signal for reversing the closed state to the open state is given to the gate electrode, the operation of the switching means 2 is surely reversed and the desired display can be displayed.

Moreover, in this lighting device, since the series circuit of the display discharge lamp B and the switching means 2 is connected to the output side of the lighting means 1, the display discharge lamp B is always rated at a high frequency. A voltage is applied. Therefore, even if the display discharge lamp B is set to any brightness by applying the dimming signal to the dimming terminal Td of the control signal generating means 6, a stable discharge maintaining state can be secured. .

In particular, when applied to a large-sized display device, many display discharge lamps are controlled by a television signal, but in order to adjust the image signal voltage and the brightness of the display discharge lamps to human eyes. Where gamma correction or the like is required, this lighting device can easily cope with this by changing the voltage waveform of the sawtooth wave in the control signal generating means 6 from linear to non-linear.

FIG. 4 shows a second embodiment of the present invention, which is basically the same as the lighting device shown in FIGS. The difference is that the blue area, on the output side of the lighting means 1,
The display discharge lamps Ba, Bb, Bc, and Bd that emit light in the green region, the green region, and the red region are connected in parallel with a series circuit of switching means 2a, 2b, 2c, and 2d each including an FET, and That is, the external electrode B6 of the display discharge lamp B is commonly connected to the lighting means side (non-switching means side). It should be noted that there is a first gap between the electrodes of each display discharge lamp B.
3 are connected in parallel, and the second capacitor 4 is connected to the gate electrode of each switching means.

According to this embodiment, the display discharge lamp Ba,
A pixel can be formed by using Bb, Bc, and Bd as one unit, and by appropriately controlling the lighting of each display discharge lamp, it is possible to realize a fine grain image display.

In particular, since the external electrode B6 of each display discharge lamp is commonly connected to the lighting means side, even if the display discharge lamps Ba, Bb, Bc and Bd are arranged close to each other, each switching means is provided. When the lighting control is performed based on the control signal given to the gate electrode of the gate electrode, the discharge is normally performed between the internal electrode B5 and the external electrode B6 provided in the predetermined display discharge lamp itself, and one of the adjacent electrodes is discharged. Irregular discharge does not occur between the internal electrode B5 of the display discharge lamp and the external electrode B6 of the other display discharge lamp. Therefore, a desired image can be displayed. When the internal electrodes B5 are commonly connected, an irregular discharge is generated between the adjacent display discharge lamps.

It should be noted that the present invention is not limited to the above-mentioned embodiment at all, and for example, both electrodes of the display discharge lamp can be arranged on the outer surface of the envelope, or a plurality of pairs of electrodes can be arranged. It is also possible to do so. Further, four or more series circuits of the display discharge lamp and the switching means can be connected in parallel on the output side of the lighting means.

[0039]

Next, an experimental example will be described. First, a first sealing portion is formed at one end of an envelope made of lead glass with an outer diameter of 8 mm and a length of 15 mm, and terbium-activated yttrium that emits light in the green region only on its inner surface. A luminescent phosphor is formed by applying a silicate phosphor (Y ₂ SiO ₅ : Tb). Next, the outer diameter is 0.8 mm and the length is 5 mm.
Of nickel wire (internal electrode) with an outer diameter of 0.45 mm
The electrode assembly formed by welding the wire is set on the stem, the stem is sealed to the other end of the envelope, and the sequinone gas is enclosed in the envelope at an enclosure pressure of 80 torr. . After that, an aluminum foil (external electrode) having a width of 3 mm and a thickness of 70 μm having an adhesive layer on one surface was wound around and adhered to the outer peripheral surface of the envelope on the side of the first sealing portion. The display discharge lamp shown in was produced.

In the lighting device shown in FIGS. 1 and 2, the lighting means is an inverter circuit for outputting a high frequency high voltage of 29 KHz and a voltage of 500 V, and the switching means is 2SK1533 manufactured by Shindengen Co., Ltd. (FET) and the capacitance of each of the first and second capacitors is 40P
When set to F, 0.1 μF, and the above-mentioned display discharge lamp was incorporated and turned on in the full light state, the lamp voltage waveform and the lamp current waveform shown in FIG. 5A were observed, and the light emission waveform was the same. The waveform shown in (b) was observed. In addition, the first
The front surface luminance on the sealing portion side was 8000 nt.

When the switching means is inverted from the closed state to the open state, the display discharge lamp is surely turned off,
The switching means did not return to the closed state again, and stable open / close control was possible.

[0042]

As described above, according to the present invention, the first capacitor having a capacitance similar to the stray capacitance C ₀ of the switching means is connected in parallel between the electrodes of the display discharge lamp. Therefore, when the switching means shifts from the closed state to the open state, the distribution voltage of the first capacitor becomes equal to or lower than the discharge sustaining voltage of the display discharge lamp. Therefore, the discharge of the display discharge lamp can be surely stopped and the desired display can be displayed.

Further, since the control terminal of the switching means is connected to the second capacitor whose capacitance value is significantly larger than the stray capacitance C ₁ thereof, when the switching means is inverted from the closed state to the open state. In addition, the voltage distributed to the second capacitor is such a low voltage that the switching means cannot be closed. Therefore, when a control signal for reversing from the closed state to the open state is given to the control terminal, the operation of the switching means is surely reversed and the desired display can be displayed.

In particular, a plurality of series circuits of the display discharge lamp and the switching means are connected in parallel on the output side of the lighting means,
Moreover, if the external electrodes of each display discharge lamp are connected in common to the lighting means side, even if each display discharge lamp is placed close to each other, there will always be a regular gap between the electrodes of the predetermined display discharge lamp itself during lighting control. A desired image display can be performed without causing irregular discharge between the inner electrode of one display discharge lamp and the outer electrode of the other display discharge lamp adjacent to each other.

[Brief description of drawings]

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

FIG. 2 is a detailed circuit diagram of control means shown in FIG.

3A and 3B are operation waveform diagrams of the circuit shown in FIG. 2, where FIG. 3A is a voltage waveform diagram of an oscillation signal in a portion, and FIG. 3B is a voltage waveform diagram in a b portion.

FIG. 4 is an electric circuit diagram showing a second embodiment of the present invention.

5A and 5B are operation waveform diagrams of the display discharge lamp, in which FIG. 5A is a waveform diagram of a lamp current and a lamp voltage, and FIG.
Is a light emission waveform diagram.

FIG. 6 is a side sectional view of a conventional example.

FIG. 7 is a side sectional view of the prior art proposed by the applicant.

FIG. 8 is a front view of FIG. 7;

FIG. 9 is an electric circuit diagram of a conventional lighting device.

FIG. 10 is an electric circuit diagram of another conventional lighting device.

[Explanation of symbols]

 B, Ba, Bb, Bc, Bd Display discharge lamp B1 Enclosure B2 First sealing part B3 Light emitting layer B4 Second sealing part B5 Electrode (internal electrode) B6 Electrode (external electrode) 1 Lighting means 2 , 2a, 2b, 2c, 2d switching means 3 first capacitor 4 second capacitor 5 resistance 6 control signal generating means 61 oscillating section 62 comparing section 63 amplifying section

Claims (7)

[Claims] 1. At least one electrode of a plurality of electrodes is arranged on the outer surface of an enclosure having a lighting means for generating high frequency high voltage and a light emitting layer on the inner surface and having a rare gas sealed in the inner space. A discharge lamp for display, a first capacitor connected in parallel to the discharge lamp for display, a control terminal, and switching means for opening and closing based on a control signal applied to this terminal. The lighting means, the display discharge lamp, and the switching means are connected in series, and the capacity of the first capacitor is distributed to the first capacitor in relation to the stray capacity of the switching means when the switching means is opened. A lighting device for a display discharge lamp, characterized in that a voltage to be set is set to be lower than a lighting maintaining voltage of the display discharge lamp. 2. The lighting device for a display discharge lamp according to claim 1, wherein the lighting means is an inverter circuit that outputs a high frequency high voltage. 3. The display discharge lamp includes an envelope having a light emitting layer formed on at least an inner surface thereof and a rare gas filled in an inner space, an external electrode arranged on an outer surface of the envelope, and an envelope. 2. The lighting device for a display discharge lamp according to claim 1, wherein the lighting device comprises an internal electrode arranged inside. 4. The lighting device for a display discharge lamp according to claim 1, wherein a plurality of series circuits of the display discharge lamp and the switching means are connected in parallel to the output side of the lighting means. 5. An external electrode and an internal electrode are arranged on the outer surface of an envelope having a lighting means for generating high frequency high voltage and a light emitting layer on the inner surface and having a rare gas sealed in the inner space. A discharge lamp for display, a first capacitor connected in parallel to the discharge lamp for display, a control terminal, and switching means for opening and closing based on a control signal applied to this terminal. A plurality of series circuits of the display discharge lamp and the switching means are connected in parallel to the output side of the lighting means, and the external electrodes of the respective display discharge lamps are connected in common, and the first capacitor Is set such that the voltage distributed to the first capacitor in relation to the stray capacitance of the switching means when the switching means is opened is lower than the lighting maintaining voltage of the display discharge lamp. Lighting device for display discharge lamp. 6. A lighting means for generating a high frequency high voltage and at least one electrode of a pair of electrodes arranged on the outer surface of an envelope having a light emitting layer on the inner surface and containing a rare gas in the inner space. A discharge lamp for display, a first capacitor connected in parallel to the discharge lamp for display, a control terminal, and switching means for opening and closing based on a control signal applied to this terminal. Then, the lighting means, the display discharge lamp, and the switching means are connected in series, and the second capacitor is connected to the control terminal of the switching means,
And the voltage distributed to the second capacitor in relation to the stray capacitance having the capacity of the second capacitor between itself and the control terminal of the switching means when the switching means is opened is such that the switching means does not close. A lighting device for a display discharge lamp, characterized in that 7. A plurality of series circuits of a display discharge lamp and a switching means are connected in parallel to the output side of the lighting means,
The lighting device for a display discharge lamp according to claim 6, wherein a second capacitor is connected to a control terminal of each switching means.