JPH06160844A - Lighting device for liquid crystal display panel - Google Patents

Abstract

(57) [Summary] [Object] To provide an illuminating device for a liquid crystal display lamp, which can realize a thin model liquid crystal display device having a screen with high uniformity and improved luminance unevenness. A diffuser plate 18 for diffusing light is arranged behind the liquid crystal display panel 10, and the fluorescent lamp 11 is preliminarily adhered and fixed to the front side of the fluorescent lamp 11, and the fluorescent lamp 11 is diffused. Is provided in the rear of the above, and a reflector 12 for efficiently reflecting and diffusing light is provided behind the above. The fluorescent lamp heater 25 is characterized by being formed in two or more patterns. The specific pattern is selected according to the shape and performance of the fluorescent lamp 11, and the liquid crystal display panel 10 and the fluorescent lamp 11 are selected.
Even if the distance L is reduced, the shadow of the fluorescent lamp heater 25, the direct light (G, H, I, etc.) and the reflected light (P, Q, R, etc.) cancel each other and reinforce each other, resulting in uneven brightness of the screen. It can be greatly improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device for a liquid crystal display panel used as a light source of a liquid crystal display device used for a television receiver, a vehicle-mounted display monitor or the like.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have come to be used as a means for enjoying television in a moving body, providing traffic information, operating conditions of various parts of an automobile, and the like. A conventional illumination device for a liquid crystal display panel used as a light source for a liquid crystal display device is configured as shown in FIGS. 8 and 9. That is, a liquid crystal display panel 1J is provided on the front surface, and a reflector 3J for efficiently using the light of the light source is arranged behind the liquid crystal display panel 1J to form a box shape as a whole, and at the front of the reflector 3J (in the box). A fluorescent lamp 4J, which is a light source, is provided in close proximity to the fluorescent lamp 4J.
A diffuser plate 2J for diffusing light is provided in front of and immediately behind the liquid crystal display panel 1J. In order to improve the starting characteristics of the fluorescent lamp 4J at low temperature, as shown in FIG. 9, a single-line fluorescent lamp heater 5J is bonded and fixed to the front side of the fluorescent lamp 4J. Further, a printed board 6J having a driving circuit for the fluorescent lamp 4J and the fluorescent lamp heater 5J is provided at the rear part of the reflector 3J, and electrically connected to the fluorescent lamp 4J and the fluorescent lamp heater 5J, respectively.

In this structure, the brightness on the liquid crystal display panel 1J is composed of direct light (B, D, etc.) from the fluorescent lamp 4J and reflected light (A, E, etc.) by the reflector 3J. Since the brightness is inversely proportional to the square of the distance, it is strong in direct light (B, D, etc.) having a short distance, and becomes weaker as the distance increases. Without reflected light (A, E, etc.) or mutual reinforcement from a plurality of fluorescent lamps 4J, the place where the direct light is strong appears as brightness unevenness on the screen. Further, the shadow (C) caused by the fluorescent lamp heater 5J appears considerably clearly on the screen. However, in reality, since there is reflected light and mutual reinforcement from a plurality of fluorescent lamps 4J, the distance L between the fluorescent lamp 4J and the liquid crystal display panel 1J is L.
If it is large, the brightness on the screen is made considerably uniform, and it is possible to manufacture a display having practically no problem.

[0004]

However, if the distance L between the fluorescent lamp 4J and the liquid crystal display panel 1J is reduced in order to realize a thin liquid crystal display device, the fluorescent lamp 4 will be reduced.
Direct light from J becomes stronger and reflected light and multiple fluorescent lamps 4
Even if there is mutual reinforcement from J, direct light or fluorescent lamp heater 5
There was a problem that the uneven brightness due to the shadow of J could not be compensated and a shadow was formed on the screen, resulting in uneven brightness.

An object of the present invention is to solve the above problems, and to provide an illuminating device for a liquid crystal display lamp, which can realize a thin model liquid crystal display device having a screen with high uniformity and improved brightness unevenness. is there.

[0006]

SUMMARY OF THE INVENTION An illumination device for a liquid crystal display lamp according to the present invention comprises a fluorescent lamp arranged behind a liquid crystal display panel, and a reflector arranged behind the fluorescent lamp for reflecting and diffusing light. It is characterized in that the fluorescent lamp heater is divided into a plurality of parts and bonded and fixed to the front side of the fluorescent lamp.

[0007]

According to the structure of the present invention, the fluorescent lamp heater is divided into a plurality of pieces and bonded and fixed to the front surface side of the fluorescent lamp, so that the fluorescent lamp can be reduced even if the distance between the fluorescent lamp and the liquid crystal display panel is reduced. By selecting the heater pattern shape that best matches the shape of the fluorescent lamp, it is possible to promote the reduction and diffusion of the direct light of the fluorescent lamp. By mutually canceling and reinforcing each other, the uneven brightness of the screen can be significantly improved, and a thin model liquid crystal display device having a highly uniform screen can be realized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an external perspective view of a liquid crystal display device using an illuminating device for a liquid crystal display panel according to an embodiment of the present invention. Reference numeral 1 denotes a screen of the liquid crystal display device, which is a transparent resin, glass, or light control film (detailed description). Omitted) etc. Reference numeral 2 is an operation button of the liquid crystal display device, 3 is a radiation hole for releasing heat inside, and 4 is a connector for connection with an external device. In addition, 5 is an escutcheon with operation buttons 2 and a touch panel printed circuit board attached,
Reference numeral 6 is a cabinet, and 7 is a screw for fixing the escutcheon 5 and the cabinet 6.

Further, the configuration of the liquid crystal display device shown in FIG. 1 will be described in detail with reference to FIGS. 2 shows the XX section in FIG. 1, and FIG. 3 shows the YY section in FIG. First, the touch panel printed circuit board 8 is fixed to the escutcheon 5 to which the operation button 2 and the like are attached with the fixing screw 21 while pressing the touch panel printed circuit board 8 with the dustproof cover 19. On the other hand, the liquid crystal display panel 10 is adhesively held by the frame fitting 16, and the reflector 12 having the fluorescent lamp 11 and the connection printed board 15 attached thereto is inserted and positioned at the rear portion thereof. The frame fitting 16 and the reflector 12 are both attached to the bracket 13 with the screw 17.
Is attached to. A cooling fan 14 is attached to the bracket 13 as needed. Further, the bracket 13 is attached to the cabinet 6 with screws 22. A main printed circuit board 9 which is a control portion of the liquid crystal display device is located at the rearmost portion, and this is attached to the cabinet 6 by a mounting screw 23. The connector 15B provided on the connection printed circuit board 15 electrically connects the fluorescent lamp 11 and the like.

An illumination device for a liquid crystal display panel according to an embodiment of the present invention used in the liquid crystal display device shown in FIG. 1 will be described with reference to FIGS. First, FIG. 4 is an exploded perspective view, in which a diffusion plate 18 for diffusing light is arranged behind the liquid crystal display panel 10. With the fluorescent lamp heater 25 previously bonded and fixed to the front side of the fluorescent lamp 11,
Is arranged behind the diffusing plate 18, and the back is provided with the reflector 12 for efficiently reflecting and diffusing light.

FIG. 5 is a cross-sectional view. As shown in FIG. 5, the fluorescent lamp 11 is held in proximity to the front inner surface of the reflector 12, and a fluorescent lamp heater 25 is fixedly adhered to the front side thereof. . The pattern of the fluorescent lamp heater 25 is divided into a plurality of lines, as shown in FIGS. 6 and 7. 6 and 7 show an example of a pattern of the fluorescent lamp heater 25. FIG. 6 shows a two-row pattern, and FIG. 7 shows a four-row pattern. Since the pattern interval and the width of the pattern itself change depending on the shape and performance of the fluorescent lamp 11, it is necessary to select the most suitable one.

According to the illuminating device for a display panel of this embodiment, the pattern of the fluorescent lamp heater 25 is divided into two or more parts, so that the fluorescent lamp 11 and the liquid crystal display panel 10 shown in FIG. Even if the distance L is reduced,
The shadow of the fluorescent lamp heater 25, the direct light (G, H, I, etc.) and the reflected light (P, Q, R, etc.) cancel each other out and reinforce each other, so that the uneven brightness of the screen can be greatly improved, and the screen with a high level of accuracy is provided. It is possible to realize a thin model liquid crystal display device having. In addition, it is possible to realize the fluorescent lamp heater 25 with a pattern shape divided into a plurality of pieces without adding new parts and at low cost, which is of great practical value.

[0013]

As described above, according to the illuminating device for a liquid crystal display panel of the present invention, the fluorescent lamp heater is divided into a plurality of parts and bonded and fixed to the front side of the fluorescent lamp, so that the fluorescent lamp and the liquid crystal display panel. Even if the distance from the fluorescent lamp is reduced, it is possible to promote the reduction and diffusion of the direct light of the fluorescent lamp by selecting the pattern shape of the fluorescent lamp heater that best matches the shape of the fluorescent lamp. The shadow of the lamp heater and the direct light and the reflected light cancel each other out and reinforce each other, so that the uneven brightness of the screen can be greatly improved, and a thin model liquid crystal display device having a screen with high uniform accuracy can be realized. In addition, it is possible to realize the fluorescent lamp heater at a low cost without using any additional parts only by using the heater having the pattern shape divided into a plurality of pieces, which is of great practical value.

[Brief description of drawings]

FIG. 1 is an external perspective view of a liquid crystal display device using an illumination device for a liquid crystal display panel according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX in FIG.

FIG. 3 is a sectional view taken along line YY in FIG.

FIG. 4 is an exploded perspective view of an illumination device for a liquid crystal display panel according to an embodiment of the present invention.

FIG. 5 is a sectional view of an illumination device for a liquid crystal display panel according to an embodiment of the present invention.

FIG. 6 is a diagram showing an example of a fluorescent lamp heater according to the embodiment.

FIG. 7 is a diagram showing an example of a fluorescent lamp heater according to the embodiment.

FIG. 8 is a cross-sectional view of a conventional liquid crystal display panel illumination device.

FIG. 9 is a diagram showing a conventional fluorescent lamp heater.

[Explanation of symbols]

 10 Liquid Crystal Display Panel 11 Fluorescent Lamp 12 Reflector 25 Fluorescent Lamp Heater

Claims (1)

[Claims] 1. An illuminating device for a liquid crystal display panel, comprising: a fluorescent lamp disposed behind a liquid crystal display panel; and a reflector arranged behind the fluorescent lamp to reflect and diffuse light. An illuminating device for a liquid crystal display panel, characterized in that a plurality of fluorescent lamp heaters are divided and bonded and fixed to the front side of the.