JP2001015291A - Sheet-form light emission lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-form light emission lighting system using a discharge lamp of inner-outer electrode type, assuring a quick rise of the photo- quantity, and capable of stabilizing the electric discharge. SOLUTION: A discharge lamp 5 is configured so that a pair of internal electrodes 7 are provided at the two ends of a bulb 6 coated on the inner surface with a phosphor and an external electrode 8 is provided along the outer surface of the bulb 6, and the external electrode 8 is contacted with an electroconductive material 9 formed on part of a reflector board 2 with a larger area than the external electrode 8 so that electric connection is established. A high-frequency lighting circuit 10 generates electric discharge between the internal electrodes 7 and external electrode 8 while the potential of the two internal electrodes 7 is kept the same. Dimmed lighting is conducted by a dimmer circuit 11 of the high-frequency lighting circuit 10. The light from the lamp 5 and the light flux reflected by the reflector board 2 are diffused by a diffusion plate 3 and irradiate onto the back surface of the light emission surface uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-emitting lighting device in which a light-emitting surface emits light in a plane.

[0002]

2. Description of the Related Art For example, in a backlight unit or a guide light of a liquid crystal display device, a surface emitting lighting device which emits light in a planar manner is used. In this case, as a light source for planar light emission,
Usually, a mercury fluorescent lamp whose emission color can be freely set is used.

FIG. 2 is a sectional view of such a surface-emitting lighting device. A mercury fluorescent lamp 1 is provided inside the surface-emitting lighting device. A reflection plate 2 is provided on the back surface of the mercury fluorescent lamp 1 to reflect light emitted from the mercury fluorescent lamp 1. In addition, a diffusion plate 3 is provided on the front surface of the mercury fluorescent lamp 1 so that the radiation light emitted from the mercury fluorescent lamp 1 and the reflection light reflected by the reflection plate 2 are diffused to uniformly irradiate the rear surface of the light emitting surface. It has become. For example, when the light emitting surface is a liquid crystal unit, the light is applied almost uniformly to the back surface of the liquid crystal unit provided on the front surface of the diffusion plate 3.

A heater 4 is provided on the reflector 2 side of the mercury fluorescent lamp 1, and when the ambient temperature decreases and the mercury vapor pressure lowers, the bulb of the mercury fluorescent lamp 1 is heated. Heating to secure the optimal mercury vapor pressure so that the lamp can be lit with a constant amount of light.

[0005]

However, in a surface-emitting lighting device using such a mercury fluorescent lamp 1, the number of components is increased due to the necessity of the heater 4, and the lighting circuit becomes complicated and expensive. Invite. In addition, the mercury fluorescent lamp 1 has a slow rise in light quantity.

Therefore, a rare gas such as xenon is sealed as a discharge medium inside a bulb having a phosphor coated on its inner surface,
Discharge lamps have been developed in which a pair of internal electrodes are provided at both ends of a bulb and external electrodes are provided along the outer surface of the bulb. Then, after the pair of internal electrodes are set to the same potential, a voltage is applied between the pair of internal electrodes and the external electrodes to turn on.

According to the inner and outer electrode type discharge lamp, it is not necessary to use mercury, which has a large environmental load, and the luminous flux rising characteristics at low temperatures are good. In addition, since the external electrode is formed along the longitudinal direction of the outer surface of the bulb and the external electrode is formed as a pair of electrodes at the internal electrode portion, the amount of light emission can be increased, and the internal electrode can be formed easily. In addition, the cost can be reduced.

However, the internal and external electrode type rare gas discharge lamps require connection terminals for electrical connection with the external electrodes, which not only increases the number of parts, but also increases the cost, and also causes an increase in the number of components inside the device. It is necessary to provide a space for arranging connection terminals.

SUMMARY OF THE INVENTION An object of the present invention is to provide a surface-emitting illuminating device capable of assembling a discharge lamp of an inner and outer electrode type with a relatively simple structure at a low cost.

[0010]

According to a first aspect of the present invention, there is provided a surface-emitting lighting apparatus having a bulb in which a fluorescent substance is coated on an inner surface and a rare gas is sealed therein. A discharge lamp in which external electrodes are formed along the outer surface, a reflecting plate that reflects light emitted from the discharge lamp, and a light emitting surface that diffuses the light emitted from the discharge lamp and the light reflected from the reflecting plate. A diffusing plate for uniformly irradiating the back surface, a conductive material formed on a part of the reflecting plate and electrically connected to an external electrode of the discharge lamp, and the internal electrode via the conductive material. And a high-frequency lighting circuit for supplying high-frequency power between the first electrode and the external electrode and lighting the discharge lamp.

In the present invention and each of the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified.

The bulb of the discharge lamp is formed of a material having translucency, and is preferably a glass bulb, but may be formed of translucent ceramics or the like. As the glass, soft glass, semi-hard glass, hard glass, quartz glass, or the like can be used as appropriate. The shape of the discharge lamp is not limited to a straight tube, a U shape, a W shape, or the like. Noble gas for discharge lamp,
For example, xenon Xe gas is sealed.

The internal electrode is provided on the bulb of the discharge lamp, and is made of a rod-shaped or plate-shaped metal having conductivity. Further, the external electrode is provided along the outer surface of the bulb, and a metal foil such as aluminum, a conductive paint film, a metal deposition film, a transparent conductive film, a relatively thin metal plate, or the like can be appropriately used. Then, a voltage is applied between the internal electrode and the external electrode. In the case of a pair of internal electrodes, a voltage is applied between the internal electrode and the external electrode while maintaining the potential of the pair of electrodes at the same potential.

The reflector is made of a material suitable for reflecting light emitted from the discharge lamp, and is preferably, for example, a white resin molded product. PP (polypropylene) made of white resin,
PC (polycarbonate) and ABS (acrylonitrile-butadiene-styrene) are used.

The light emitted from the discharge lamp and the light reflected from the reflector are uniformly radiated on the back of the light-emitting surface by a diffusion plate provided on the back of the light-emitting surface. As the light emitting surface, for example, a liquid crystal unit (LCD) is used.

A conductive material is applied to a part of the reflection plate. The conductive material is applied to at least a portion near the external electrode of the discharge lamp, and is in contact with and electrically connected to the external electrode of the discharge lamp. The conductive material is formed in an area larger than the contact area of the external electrode. This increases the contact area with the external electrode, promotes the heat radiation of the discharge lamp, and facilitates the connection of the external electrode to a high-frequency lighting circuit described later.

The high-frequency lighting circuit causes a discharge between the internal electrode and the external electrode. The connection of the external electrode to the high-frequency lighting circuit is performed via a conductive material. Therefore, since the area in which the conductive material is formed is larger than the external electrode, the connection between the high-frequency lighting circuit and the external electrode becomes easy, and no special connection terminal is required. The high frequency lighting circuit has a dimming circuit for dimming the discharge lamp.

According to a second aspect of the present invention, in the surface emitting lighting device according to the first aspect, the high frequency lighting circuit includes a PWM dimming circuit for controlling a high frequency power supply supplied to the discharge lamp by PWM. Features.

According to the present invention, the dimming circuit of the high-frequency lighting circuit controls the high-frequency power supplied to the discharge lamp by PWM (pulse width modulation). Thus, appropriate dimming control can be performed.

In a third aspect of the present invention, in the surface emitting lighting device according to the first aspect, the conductive material is transparent.

In the present invention, a transparent material is used as the conductive material in order to improve the reflection efficiency of the luminous flux on the reflection plate on the back surface. Thereby, the light flux transmitted through the conductive material is efficiently reflected by the reflector. As the transparent material, for example, tin oxide is used.

According to a fourth aspect of the present invention, in the surface emitting lighting device of the first aspect, the conductive material is aluminum or silver deposited.

In the present invention, the conductive material itself reflects the light beam instead of the transparent conductive material. For example, a conductive material obtained by depositing aluminum or silver is used.

[0024]

Embodiments of the present invention will be described below. FIG. 1 is an explanatory diagram of a surface-emitting lighting device according to an embodiment of the present invention. FIG. 1A is a cross-sectional view of FIG.
(B) is a side view of the discharge lamp.

In FIG. 1A, inside and outside of a surface-emitting illuminating device, a discharge lamp 5 of an inner and outer electrode type is provided, and a reflection plate 2 is provided on the back surface thereof. The discharge lamp 5 is provided with a pair of internal electrodes 7 at both ends of a bulb 6 and external electrodes 8 along the outer surface of the bulb. A fluorescent substance is applied to the inner surface of the bulb 6, and a rare gas such as xenon is sealed as a discharge medium.

The reflection plate 2 is made of a white resin in order to enhance the reflection efficiency of the light beam, and reflects the light emitted from the discharge lamp 5 efficiently. The light emitted from the discharge lamp 5 and the light flux reflected by the reflection plate 2 are diffused by the diffusion plate 3 so as to uniformly irradiate the back surface of the light emitting surface. For example, when the light emitting surface is a liquid crystal unit, a light beam is irradiated almost uniformly on the back surface of the liquid crystal unit provided on the front surface of the diffusion plate 3.

A conductive material 9 is applied to a part of the reflecting plate 2 and is in contact with and electrically connected to the external electrode 8 of the discharge lamp 5. That is, tin oxide, which is a transparent conductive material 9, is applied to the reflector 2 over a larger area than the contact area of the external electrode 8, and the conductive material 9 promotes heat radiation of the discharge lamp 5. Further, as described later, connection of the external electrode 8 to the high-frequency lighting circuit is facilitated.

Here, the reason why the conductive material 9 is made transparent is as follows.
This is for improving the reflection efficiency of the light beam on the reflection plate 2 on the back surface. Therefore, the conductive material 9 only needs to reflect the conductive material 9 itself, and may be a conductive material 9 formed by vapor deposition of aluminum or silver instead of transparent tin oxide.

As described above, since the transparent conductive material 9 is formed in an area larger than the contact area of the external electrode 8, the contact area with the external electrode 8 can be increased and the discharge can be stabilized. .

Next, as shown in FIG.
A pair of internal electrodes 7a and 7b are provided at both ends of the bulb 6, and an external electrode 8 is formed along the longitudinal direction of the outer surface of the bulb 6. This external electrode 8 is formed of a pair of internal electrodes 7a, 7b at a portion of the pair of internal electrodes 7a, 7b.
Are formed so as to surround from outside. Thereby, the light emission amount can be increased.

The pair of internal electrodes 7a and 7b are connected so as to have the same potential and are connected to a high-frequency lighting circuit 10, and the external electrodes 8 are connected to the high-frequency lighting circuit 10 via a conductive material 9. ing. This high-frequency lighting circuit 10
Thus, a voltage is applied between the pair of internal electrodes 7a, 7b and the external electrode 8, and the discharge lamp 5 is configured to generate a discharge between the internal electrodes 7a, 7b and the external electrode 8 to light up.

The high-frequency lighting circuit 10 has a dimming circuit 11 for performing dimming lighting, and is a discharge lamp 5 of an inner and outer electrode type. It is controlled by. Therefore, dimming lighting can be easily performed.

[0033]

According to the first aspect of the present invention, since the inner and outer electrode type discharge lamp in which a rare gas is sealed is used, light rises quickly and the amount of light is not affected by the ambient temperature. In addition, since a conductive material is applied to the reflector and brought into contact with the external electrode,
No special connection terminal is required, and it can be easily assembled.
Furthermore, the area between the external electrodes can be increased, and the discharge between the internal electrodes can be further stabilized.

According to the second aspect of the present invention, since the inner and outer electrode type discharge lamp in which a rare gas is sealed is used, the dimming control of the discharge lamp can be appropriately performed by PWM.

According to the third aspect of the present invention, the light flux transmitted through the transparent conductive material is efficiently reflected by the reflecting plate.
There is no decrease in luminous efficiency.

According to the fourth aspect of the present invention, since the conductive material itself reflects the light flux, the luminous efficiency does not decrease.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a surface-emitting lighting device according to an embodiment of the present invention, and FIG.
(B) is a side view of the discharge lamp.

FIG. 2 is a cross-sectional view of a conventional surface-emitting lighting device.

[Explanation of symbols]

 2 Reflecting plate 3 Diffusion plate 5 Discharge lamp 6 Bulb 7 Internal electrode 8 External electrode 9 Conductive material 10 High frequency lighting circuit 11 Dimming circuit

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01J 65/00 H05B 41/392 G H05B 41/02 F21V 7/12 H 41/392 G02F 1/1335 530

Claims (4)

[Claims] A discharge lamp having an inner surface coated with a phosphor and filled with a rare gas, the inner electrode being sealed in the bulb and an outer electrode being formed along the outer surface of the bulb; A reflector for reflecting light emitted from the electric light;
A diffusing plate for diffusing light emitted from the discharge lamp and reflected light from the reflecting plate to uniformly irradiate the back surface of the light emitting surface;
A conductive material formed on a part of the reflection plate and electrically connected to and in contact with an external electrode of the discharge lamp; and a high-frequency power supply between the internal electrode and the external electrode via the conductive material. And a high-frequency lighting circuit for lighting the discharge lamp and supplying light to the discharge lamp. 2. The surface-emitting lighting device according to claim 1, wherein the high-frequency lighting circuit includes a PWM dimming circuit that controls a high-frequency power supplied to the discharge lamp by PWM. 3. The surface emitting lighting device according to claim 1, wherein the conductive material is transparent. 4. The surface emitting lighting device according to claim 1, wherein the conductive material is aluminum or silver deposited.