JPH10222083A - Flat board type source of light and liquid crystal display thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend a life, reduce power consumption and make a device safe. SOLUTION: This liquid crystal display device is provided by sealing a front plate 10, an insulation base board 20, and side boards 50 in one air-tight body, coating the insulation base board 20 with phosphor 60, filling a discharge space 30 with mercury and a starting gas, providing a pair of discharging electrodes 90, 91 parallel to each other on the outside surface of the front plate 10, arranging the discharging electrodes 90, 91 at both end parts of the discharge space 30, and bonding metallic tapes of 5mm in width consisting of aluminum to the front plate 10 as discharging electrodes 90, 91.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television, a game machine, an information video equipment such as a car navigation system, an OA equipment such as a word processor, and a display incorporating a light source using a display element such as a liquid crystal display device requiring a backlight. The present invention relates to a flat light source and a liquid crystal display device which are used in a system or the like and emit light in a plane.

[0002]

2. Description of the Related Art Liquid crystal display devices 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 of the camera is required. As the backlight, a combination of a small-diameter fluorescent lamp and an acrylic resin light guide is mainly used, but a flat discharge lamp is also used.

FIG. 5 is a sectional view showing a conventional flat rare gas discharge lamp described in, for example, JP-A-3-225743. As shown in the figure, a front plate 10 having a light-transmitting property, a light-transmitting front plate 10, an insulating substrate 20, and a side plate 50 are hermetically sealed with low-melting glass to form a sealed container. Is filled with a rare gas mainly composed of xenon gas. Further, spacers 40 made of uniform small-diameter glass beads are dispersedly arranged between the front plate 10 and the insulating substrate 20, and the inner surface of the front plate 10 and the insulating substrate 20 is coated with a phosphor 60. A transparent electrode 70 and a metal film electrode 80 are formed on the outer surfaces of the face plate 10 and the insulating substrate 20, respectively.

In this flat-type rare gas discharge lamp, when a high-frequency voltage is applied between the transparent electrode 70 and the metal film electrode 80, a rare gas discharge is generated in the discharge space 30, thereby exciting the phosphor 60. Then, light is emitted, and light is emitted through the transparent electrode 70.

[0005]

In this flat type rare gas discharge lamp, a transparent electrode 70 and a metal film electrode 80 are provided on almost all outer surfaces of a front plate 10 and an insulating substrate 20, respectively.
The phosphor 60 is applied to the surface on the opposite side of the insulating substrate 20. For this reason, since charged particles such as ions collide with the phosphor 60 during discharge, the phosphor 60 is deteriorated, the luminance is greatly reduced, and the life is short. In addition, since a discharge is generated between the transparent electrode 70 and the metal film electrode 80 facing each other, only a negative glow occurs in the discharge mode, so that the luminous efficiency is poor and the power consumption is large.
Further, the transparent electrode 70 and the metal film electrode 8 for preventing electric shock etc.
However, since the transparent electrode 70 and the metal film electrode 80 are formed on both the front and back surfaces of the discharge lamp and the area of the transparent electrode 70 and the metal film electrode 80 is large,
There was a risk of electric shock and safety issues.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a flat light source having a long life, low power consumption, and safety.

[0007]

In order to achieve this object, according to the present invention, in a flat light source, a transparent front plate serving as a light emitting surface, an insulating substrate coated with a phosphor, and a side plate are provided. A closed container is formed by combining the closed container and the discharge gas is sealed in the closed container, and a plurality of discharge electrodes are formed on the outer surface of the front plate.

In this case, a discharge electrode made of a thin metal plate is used.

The discharge electrode is made of a transparent conductive film.

[0010] Further, as the discharge electrode, an electrode composed of a transparent conductive film and a stripe-shaped or mesh-shaped metal conductor provided so as to overlap at least a part of the transparent conductive film is used.

In these cases, a protective layer is provided on the inner surface of the front plate.

In these cases, a spacer is provided between the front plate and the insulating substrate in a direction crossing the discharge electrodes, and the phosphor is applied to the surfaces of the insulating substrate and the spacer.

Further, at least one of the side plate and the spacer is formed on the insulating substrate by using a thick film printing method.

A part or the whole of the discharge electrode is covered with a transparent or white insulating film.

In the liquid crystal display device, the above-mentioned flat light source is used.

[0016]

FIG. 1 is a partially cutaway perspective view showing a flat light source according to the present invention. As shown in the figure, a front plate 10 made of, for example, soda glass, an insulating substrate 20 made of soda glass, ceramic, or the like, and a side plate 50 are integrally hermetically sealed with, for example, low melting point glass (not shown). A phosphor 60 is applied to the inner surface of the substrate, and mercury and a mixed gas such as argon or neon-argon or xenon, krypton, argon, or the like is used as a starting gas in the discharge space 30.
A rare gas discharge gas such as helium or neon is sealed in,
The filling pressure is from 10 Pa to 100 kPa. Further, a pair of strip-shaped discharge electrodes 90, 91 parallel to each other are provided on the outer surface of the front plate 10, and the discharge electrodes 90, 91 are located at both ends of the discharge space 30, and the discharge electrodes 90, 91 5mm wide metal tape made of aluminum
0 is provided. The discharge space 30 has a size of, for example, 110 mm × 85 mm and has a light emitting surface with a diagonal of about 5.5 inches.

In this flat light source, the discharge electrode 9
When a high-frequency voltage (sine wave, rectangular wave, or pulse voltage) of 10 kHz to 1 MHz is applied to 0 and 91, electric field discharge is performed in the discharge space 30, and the phosphor 60 is excited and emits light by ultraviolet rays generated by the discharge. Light is emitted through the front plate 10.

In such a flat light source, since the discharge electrodes 90 and 91 are formed on the same surface of the front plate 10, ions generated by the discharge are applied to the phosphor 60 applied to the insulating substrate 20. Etc. do not collide directly,
0 is less deteriorated and the life is longer. Also, the discharge electrode 9
Providing 0 and 91 at both ends of the discharge space 30 increases the discharge length, so that a positive column is generated when the discharge is performed. Therefore, the phosphor 60 is mainly excited by the positive column, and has high luminance and high luminous efficiency, so that the power consumption is small. Also, discharge electrodes 90 and 91 are provided only on one side,
In addition, since the discharge electrodes 90 and 91 need only be provided at both ends of the discharge space 30, the area of the discharge electrodes 90 and 91 is small, so that the prevention of electric shock can be easily performed, which is safe. Also,
Since the discharge electrodes 90 and 91 are provided by bonding a metal tape to the outer surface of the front plate 10, it can be manufactured very easily.

As the metal thin film, a metal foil or the like can be used other than the metal tape. Also, as the discharge electrode, a transparent conductive film such as an ITO film or a Nesa film, or a thick printed conductive film may be used. When a discharge electrode made of a transparent conductive film is used, the area of the light emitting surface is increased. When a discharge electrode composed of a thick-film printed conductive film is used, it can be manufactured very easily. Further, when the light emitting surface becomes large, not only a pair of discharge electrodes but also a plurality of discharge electrodes may be provided in the middle or divided. Further, if the inner surface of the front plate 10 (discharge space 30 side) is covered with a protective layer (not shown) made of MgO or the like having a thickness of several thousand Å, the operating voltage can be reduced, and the spatter can be reduced. Therefore, the life can be further extended.

FIGS. 2A and 2B are views showing a part of another flat light source according to the present invention. As shown in FIG.
Discharge electrodes 93 and 94 in which a stripe-shaped metal conductor 95 and a mesh-shaped metal conductor 96 are formed on a transparent conductive film 92 such as an ITO film or a Nesa film formed on the outer surface of the substrate 0 are used. . A terminal 97 for connection to an external circuit is provided.
Are formed integrally with the metal conductors 95 and 96.

In this flat light source, the area of the light-emitting surface can be increased, and even if the resistance of the transparent conductive film 92 is high, the metal electrodes 95 and 96 can be formed in an overlapping manner to form the discharge electrodes 93 and 94. Since the entire surface can be set to substantially the same potential, the uniformity of discharge increases, and the uniformity of light emission can be improved. Further, since the metal conductors 95 and 96 have very small resistance, even if the discharge current is increased to obtain high luminance, the resistance loss of the transparent conductive film 92 does not matter.

FIG. 3 is a partially cut perspective view showing another flat light source according to the present invention. As shown in FIG.
Spacer 10 having a substantially triangular cross section on the surface on the side of discharge space 30
0 is provided, and the spacer 100 is provided in a direction crossing the discharge electrode 90. In addition, the phosphor 60 is attached to the front plate 1
0 and the insulating substrate 20
It is applied to the surface of.

In this flat light source, the spacer 10
0 is provided between the front plate 10 and the insulating substrate 20, so that even if the inside of the discharge space 30 is under reduced pressure, the spacer 1
Since the front plate 10 and the insulating substrate 20 can be prevented from being damaged by 00, the light emitting surface can be enlarged, and the front plate 10 and the insulating substrate 20 can be thinned to reduce the weight.

The spacer 100 need not be provided over the entire discharge space 30, but may be provided only partially. Also, the shape of the spacer 100 is not limited to the above-described triangle,
For example, the shape may be selected such that the light emitting surface has as little luminance unevenness as possible, such as a shape that gradually becomes thinner toward the front plate 10 in a stepwise manner, a spherical shape, an elliptical shape, and the like. Spacer 1
00, the side plate 50 is attached to the insulating substrate 2 together or separately.
It may be formed by using a thick-film printing method on top of 0, and in this case, it can be manufactured very easily.

FIG. 4 is a sectional view showing another flat type light source according to the present invention. As shown in the figure, a transparent insulating sheet 110 such as, for example, PET (polyethylene terephthalate) is adhered on the discharge electrodes 90 and 91.

In this flat light source, the insulating sheet 1
10, the electric shock can be surely prevented, so that it is safer.

The insulating sheet, which is an insulating film, is
0, or may be provided so as to cover at least a part of the discharge electrodes 90 and 91. In addition, if a white insulating sheet is used as the insulating film, it can also serve as a diffusion sheet. Further, an insulating film, an insulating layer formed by a thick film printing method like the discharge electrode, or the like may be used as the insulating film.

The flat light source shown in FIGS. 1 to 4 can be used for a backlight of a liquid crystal display.

[0029]

In the flat panel light source and the liquid crystal display device according to the present invention, since the ions and the like generated by the discharge do not directly collide with the phosphor coated on the insulating substrate, the deterioration of the phosphor is small. , Long life. In addition, since the discharge length is long, the phosphor is mainly excited by the positive column, so that the luminance is high and the luminous efficiency is high, so that the power consumption is small. Also,
Since the discharge electrode is provided only on one surface and the discharge electrode does not need to be provided on the entire surface, the area of the discharge electrode is small, so that it is safe.

When a discharge electrode made of a thin metal plate is used, it can be manufactured very easily.

When a discharge electrode made of a transparent conductive film is used, the area of the light emitting surface can be increased.

When a discharge electrode composed of a transparent conductive film and a striped or mesh-shaped metal conductor provided so as to overlap at least a part of the transparent conductive film is used, the area of the light emitting surface is increased. It is possible,
In addition, since the entire surface of the discharge electrode can be set at substantially the same potential, the uniformity of the discharge is increased, and the uniformity of the light emission can be improved.

Further, when a protective layer is provided on the inner surface of the front plate, the operating voltage can be reduced and spatter can be reduced, so that the life can be further extended.

Further, a spacer is provided between the front plate and the insulating substrate in a direction crossing the discharge electrode, and when a phosphor is applied to the surfaces of the insulating substrate and the spacer, even if the inside of the discharge space is in a reduced pressure state, the spacer is used. Since the front plate and the insulating substrate can be prevented from being damaged, the light emitting surface can be enlarged, and the front plate and the insulating substrate can be made thin to reduce the weight.

Further, when at least one of the side plate and the spacer is formed on the insulating substrate by using the thick film printing method, it can be manufactured very easily.

When a part or the whole surface of the discharge electrode is covered with a transparent or white insulating film, electric shock can be surely prevented, so that it is safer.

[Brief description of the drawings]

FIG. 1 is a partially cut perspective view showing a flat light source according to the present invention.

FIG. 2 is a diagram showing a part of another flat light source according to the present invention.

FIG. 3 is a partially cut perspective view showing another flat light source according to the present invention.

FIG. 4 is a sectional view showing another flat light source according to the present invention.

FIG. 5 is a cross-sectional view showing a conventional flat rare gas discharge lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Front plate 20 ... Insulating substrate 50 ... Side plate 60 ... Phosphor 90 ... Discharge electrode 91 ... Discharge electrode 92 ... Transparent conductive film 93 ... Discharge electrode 94 ... Discharge electrode 95 ... Metal conductor 96 ... Metal conductor 100 ... Spacer 110 ... Insulation Sheet

Claims (9)

[Claims] An airtight container is constituted by combining a front plate having translucency, an insulating substrate coated with a phosphor, and a side plate.
A flat light source, characterized in that a discharge gas is sealed in the closed vessel and a plurality of discharge electrodes are formed on an outer surface of the front plate. 2. A flat light source according to claim 1, wherein said discharge electrode is made of a thin metal plate. 3. A flat light source according to claim 1, wherein said discharge electrode is made of a transparent conductive film. 4. The discharge electrode according to claim 1, wherein the discharge electrode comprises a transparent conductive film and a stripe-shaped or mesh-shaped metal conductor provided so as to overlap at least a part of the transparent conductive film. 2. The flat light source according to 1. 5. The flat light source according to claim 1, wherein a protective layer is provided on an inner surface of said front plate. 6. The apparatus according to claim 1, wherein a spacer is provided between said front plate and said insulating substrate in a direction crossing said discharge electrode, and said phosphor is applied to surfaces of said insulating substrate and said spacer. 6. The flat light source according to any one of 1 to 5. 7. The flat light source according to claim 6, wherein at least one of said side plate and said spacer is formed on said insulating substrate by using a thick film printing method. 8. The discharge electrode according to claim 1, wherein at least a part of said discharge electrode is covered with a transparent or white insulating film.
A flat light source according to any one of the above. 9. A liquid crystal display device using the flat light source according to claim 1.