JPH11329356A - Discharge device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the uniformity of luminance of a flat-plate type discharge device, and to further eliminate noise disturbance caused by application of high-frequency voltage or discharge. A translucent front plate and a rear plate serving as a light emitting surface.
A pair of parallel discharge electrodes 4 and a dielectric layer 5 covering the surface of the discharge electrodes 4 are provided on the inner surface of the front plate 1, and a phosphor 6 is provided on the inner surface of the hermetic container. In a flat-plate type discharge device in which the inside of the hermetic container is coated with a discharge gas, the insulating sheet 8 having excellent thermal conductivity including almost the entire outer surface of the back plate of the hermetic container and the exhaust pipe is adhered to the conductive adhesive 9. To coat. [Effect] The temperature distribution of the airtight container becomes uniform, and a display with good luminance uniformity can be performed. In addition, by using a conductive adhesive for the insulating sheet, it can serve as a proximity conductor, improve starting characteristics, and provide an electromagnetic shield for noise generated by high-frequency voltage application and discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat discharge device which emits light in a plane, and more particularly to a flat panel discharge device using a display element such as a liquid crystal panel which requires a backlight, such as a television.
The present invention relates to a flat panel light source in an information video device such as a game machine or a car navigation system, an OA device such as a word processor, or a display system incorporating a light source.

[0002]

2. Description of the Related Art Liquid crystal panels are widely used for various information and image displays such as personal computers and televisions because of their thinness, lightness, and low power consumption. A backlight that supplies light from the back is required. The backlight generally used is mainly a combination of a small-diameter fluorescent lamp and an acrylic resin light guide, but a flat discharge lamp is also used.

FIG. 4 is a sectional view of a conventional flat light source described in, for example, Japanese Patent Application Laid-Open No. 9-115483. As shown in the figure, a translucent front plate 1 made of soda glass or the like.
The insulating substrate 2 made of soda glass, ceramic, or the like, and the side plate 3 are hermetically sealed integrally with, for example, low-melting glass (not shown) to form a flat hermetic container. A pair of discharge electrodes 4 parallel to each other are provided on the inner surface of the front plate 1 serving as a light emitting surface, and the surface of the discharge electrodes 4 is covered with a dielectric layer 5. A phosphor 6 is applied to the inner surface of the insulating substrate 2 and a discharge space 7 in the hermetic container is a mercury and mixed gas such as argon or neon-argon as a starting gas, or xenon, krypton, helium, or the like. A discharge gas of a rare gas such as neon is sealed.

[0004] The above-mentioned conventionally known flat-type discharge device includes:
By applying a high-frequency voltage between the discharge electrodes 4, a discharge occurs in the discharge space 7, and the ultraviolet rays generated by the discharge cause
The phosphor 6 is excited to emit light. Light emitted by the phosphor is radiated to the outside through the front plate 1.

[0005]

In order to use a flat discharge device as a backlight of a liquid crystal display device, it is important to have good uniformity of luminance of light emission and to cut off noise generated by applying a high frequency voltage or discharging. Condition. The above-mentioned conventional flat discharge device generates a discharge between a pair of opposed discharge electrodes 4-1 and 4-2 provided on a front plate serving as a light emitting surface, so that the entire discharge space 7 emits uniform light. It works as follows. However, in the conventional flat discharge device, the temperature distribution of the hermetic container becomes non-uniform due to the discharge, and the discharge becomes unstable during operation, and brightness unevenness, flicker, shrinkage of the positive column, and the like are likely to occur. However, there is a problem that the light emission becomes non-uniform and the luminance uniformity is deteriorated. In addition, there is a problem that noise generated by application or discharge of a high-frequency voltage may hinder driving or display of a liquid crystal device, or noise may enter another acoustic system.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problem, and has a high luminance uniformity with a simple configuration.
Another object of the present invention is to provide a flat discharge device having a noise blocking effect.

[0007]

According to the present invention, a flat airtight container is provided by combining a light-transmitting front plate serving as a light emitting surface and a rear plate consisting of a box-shaped container. A flat-type discharge device, wherein at least a pair of discharge electrodes parallel to each other are provided on an inner surface of the front plate, a phosphor is applied on an inner surface of the back plate, and a discharge gas is sealed in the hermetic container. In the above, an insulating sheet (heat radiating layer) having excellent thermal conductivity is adhered to almost the entire outer surface of the back plate of the hermetic container using a conductive adhesive. Preferably, the insulating sheet covers the entire outer surface of the back plate and the exhaust pipe. According to the present invention, an illuminating device is configured by using the flat discharge device as a light source. Furthermore, the present invention constitutes a liquid crystal display device using the flat discharge device as a backlight.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a perspective view having a partial cross section of an embodiment of a flat discharge device according to the present invention, and a cross sectional view taken along the line AA of FIG. 1, respectively. As shown in the figure, a translucent front plate 1 made of, for example, soda glass or the like and a back plate 2 made of a box-shaped container made of soda glass, ceramics, or the like are integrally formed of, for example, low melting glass (not shown). To form a flat airtight container. A pair of discharge electrodes 4-1 parallel to each other are provided on the inner surface of the front plate 1.
4-2 is provided, and the surface of the discharge electrode 4 is covered with a dielectric layer 5 provided by a thick film printing method or the like. A phosphor 6 is applied to the inner surfaces of the front plate 1 and the back plate 2, and a discharge space 7 in the hermetic container is filled with a discharge gas of mercury or a rare gas. On the outer surface of the back plate 2, an insulating sheet 8 having good thermal conductivity to a silicon structural material and filled with particles of, for example, aluminum oxide, boron nitride or the like is provided with a conductive adhesive layer. 9, the rear plate 2
Is provided so as to adhere to the entire outer surface including the exhaust pipe 10.

As shown in FIG. 3, the driving method of the flat discharge device according to the present embodiment is, for example, one of a pair of electrodes 4-.
1, a rectangular wave voltage a having a constant period of a low potential -Vh and a high potential V1 is applied to the other side 4-2 of the pair of electrodes.
, A low-potential-Vh and a high-potential V2, which are shifted by a half-period in phase, are applied with a constant-cycle rectangular wave voltage b. By using such a driving method, a discharge is generated in the discharge space 7, and the phosphor 6 is excited by the ultraviolet rays generated by the discharge to emit light, and the light is emitted to the outside through the front plate 1.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.
For example, the number of discharge electrodes does not need to be one, but may be plural. It is clear that the materials used such as glass and insulating sheet are not limited to those described above.

Further, the discharge device of the present invention has a high luminance, and the lighting device can be constituted by adding a power source for applying a high-frequency voltage as described with reference to FIG. Further, a display device is constituted by using the discharge device of the present invention as a backlight of a display device using a conventionally known liquid crystal.

[0012]

As described above, the flat discharge device of the present invention uses a material having good thermal conductivity for the insulating sheet provided on the outer surface of the back plate, so that the heat generated by discharge can be reduced by the airtight container. The temperature distribution can be kept uniform, and a display with good luminance uniformity can be made. In particular, in the manufacture of this type of discharge device, it is inevitable to provide an exhaust tube for exhausting the airtight container composed of the box-shaped back plate and the front plate and filling the discharge gas, and therefore, the lighting device is turned on. Occasionally, the exhaust hole portion becomes a cooling portion, and mercury vapor gradually gathers in the cooling portion. For this reason, the mercury vapor pressure in the discharge space was reduced, which caused a decrease in luminance and luminance uniformity. However, according to the present invention, since the conductive adhesive is used, the exhaust pipe section can be easily formed. Up to the insulating sheet, the temperature at the rear of the exhaust can be kept constant, and the luminance uniformity can be improved.

Even if the adhesive is conductive, the insulating sheet is made of an insulating material. Therefore, even if the rear plate 2 may come into contact with an electric component such as a driving circuit board or a circuit component, the driving circuit is not affected. No short circuit occurs, and the circuit is not damaged. Furthermore, since the adhesive layer has conductivity, it can be used as a proximity conductor, improving characteristics such as a reduction in discharge starting voltage, and connecting the conductive adhesive layer to a ground potential, An electromagnetic shield that blocks noise generated by application of a high-frequency voltage or discharge can be provided.

[0014]

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional perspective view of an embodiment of a flat discharge device according to the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of the flat discharge device of FIG.

FIG. 3 is a driving voltage waveform of an embodiment of the flat discharge device according to the present invention.

FIG. 4 is a cross-sectional view of a conventional flat discharge device.

[Explanation of symbols]

1 ... front plate, 2 ... rear plate, 3 ... side plate, 4 ...
... discharge electrode, 5 ... dielectric layer, 6 ... phosphor, 7 ...
... discharge space, 8 ... insulating sheet, 9 ... conductive adhesive layer, 10 exhaust holes.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masashi Tsuchiya 6-16, Shinmachi, Omachi, Ome-shi, Tokyo 2 Within the Heater Lighting Division of Hitachi, Ltd. (72) Inventor Yasushi Ikuta 6-16, Shinmachi, Ome-shi, Tokyo Of 2 Ome Sangyo Co., Ltd.

Claims (7)

[Claims] 1. A flat airtight container is formed by combining a light-transmitting front plate and a rear plate made of a box-shaped container, and at least one pair of discharge electrodes is provided on an inner surface of the front plate. In a discharge device in which a phosphor is applied to the inner surface of the back plate and a discharge gas is sealed in the hermetic container, an insulating sheet is bonded to the outer surface of the back plate via a conductive adhesive. Discharge device. 2. The discharge device according to claim 1, wherein the insulating sheet is adhered to the entire outer surface of the back plate via a conductive adhesive, and is extended to cover the exhaust pipe. . 3. The discharge device according to claim 1, wherein an insulator having good thermal conductivity is used as the insulating sheet. 4. The discharge device according to claim 1, wherein a material obtained by filling a silicon structural material with particles having good heat conductivity is used as said insulating sheet having good heat conductivity. 5. The discharge device according to claim 1, further comprising a portion for connecting the conductive adhesive to a ground potential. 6. An illuminating device using the flat discharge device according to claim 1 as a light source. 7. A liquid crystal display device using the flat discharge device according to any one of claims 1 to 5 as a backlight.