JPH0676931U - LCD display lighting structure - Google Patents

Abstract

(57) [Summary] [Object] To provide a lighting structure for a liquid crystal display, which uses a light emitting diode that does not generate heat damage as a light source and has a small and simple structure. [Structure] For a liquid crystal display 1 having a semi-transmissive reflection plate 2 provided on the back surface thereof, a diffusion filter 3 is arranged on the back surface of the semi-transmission reflection plate 2 at intervals, and further as a light source on the back surface of the diffusion filter 3. The light emitting diode chip 4 is arranged. The light emitted from the light emitting diode chip 4 is sufficiently diffused by the diffusion filter 3 and the space subsequent thereto, and the diffused light uniformly illuminates the liquid crystal display 1 from the back surface through the semi-transmissive reflection plate 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lighting structure for a liquid crystal display.

[0002]

[Prior art]

 A typical illumination structure of a conventional liquid crystal display is shown in FIGS. 3 and 4. The one shown in FIG. 3 is called a light guide plate edge light type. In this, a light guide plate 13 made of a transparent resin having a special shape is placed on the printed circuit board 5, a semi-transmissive reflection plate 2 and a liquid crystal display 1 are mounted thereon, and these are fixed to the printed circuit board 5 by a holder 7. . A lamp 14 is used as a light source and is arranged toward the edge surface 16 of the light guide plate 13.

The light guide plate 13 having the special shape has a bottom surface formed as a reflection curved surface 15, and the light emitted from the lamp 14 is reflected by the reflection curved surface 15 to pass through the semi-transmissive reflection plate 2. And illuminates the liquid crystal display 1 from the back. In this type, since the light source 14 can be placed on the side surface, the overall structure can be made thin. However, in order to uniformly illuminate the liquid crystal display 1, the shape of the reflection curved surface 15 of the light guide plate 13 is important, and it is also in design that the reflection curved surface 15 has an ideal shape. It is difficult to manufacture, and it has the problem of high cost.

Next, the one shown in FIG. 4 is called a housing type. In this system, a lamp 14 is arranged in a housing 19 made of white semi-transmissive resin, and the liquid crystal display 1 is illuminated from the rear surface by light transmitted through the housing 19. This type provides uniform illumination to the liquid crystal display 1 by providing a sufficient distance between the liquid crystal display 1 and the lamp 14 and further diffusing the light transmitted through the housing 19. It is what is done.

However, this type requires a large distance between the liquid crystal display 1 and the lamp 14 in order to achieve uniform illumination, so that the overall structure becomes large due to its thickness. It has a problem.

Further, in each of the conventional examples described above, the lamp 14 of the light source generates heat, which may cause heat damage to electronic components and the like in the surroundings. On the other hand, attempts have been made to use light emitting diodes, which generate little heat, as light sources for illuminating liquid crystal displays. However, since the light emitted from the light emitting diode has a strong directivity, even if the light emitting diode is divided into a plurality of parts and the liquid crystal display 1 is illuminated by arranging them in a dispersed manner, uneven illumination is inevitable. Therefore, conventional lighting of liquid crystal displays by light emitting diodes has not been realized.

[0007]

[Problems to be solved by the device]

 As explained above, the conventional lighting structure of each liquid crystal display has a complicated structure, is difficult to be miniaturized due to thick overall structure, and causes heat damage by the light source. As described above, each has its own problems, and an illumination structure for a liquid crystal display that has solved all of these problems has not been realized.

In view of this point, an object of the present invention is to provide an illumination structure for a liquid crystal display, which uses a light emitting diode that does not generate heat damage as a light source and has a small size and a simple structure.

[0009]

[Means for Solving the Problems]

 In the present invention, for a liquid crystal display having a semi-transmissive reflector on the back side, diffusion filters are arranged at intervals on the back side of the semi-transmissive reflector, and a light emitting diode as a light source is provided on the back side of the diffusion filter. Deploy.

[0010]

[Action]

 According to the above means, the light emitted from the light emitting diode is diffused by the diffusion filter, and the diffused light illuminates the liquid crystal display from the rear surface through the semi-transmissive reflection plate arranged at a distance from the diffusion filter. As a result, the highly directional light from the light emitting diode is also sufficiently diffused by the diffusion filter, the space following it, and the semi-transmissive reflection plate to uniformly illuminate the liquid crystal display.

[0011]

【Example】

 An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side sectional view of an illumination structure of a liquid crystal display, and FIG. 2 is a plan sectional view taken along the line AA of FIG. The liquid crystal display 1 and the semi-transmissive reflection plate 2 on the back of the liquid crystal display 1 are arranged on the printed circuit board 5 via the case 6. The case 6 is made of white resin such as ABS resin. Inside the case 6, a plurality of light emitting diode chips 4 are arranged at equal intervals on a printed circuit board 5, and a diffusion filter 3 is semi-transmissive between the semi-transmissive reflector 2 and the light-emitting diode chip 4. It is arranged at a distance from the reflector 2.

The diffusion filter 3 is formed of, for example, an acrylic resin containing a diffusing agent. The diffusion filter 3 and the case 6 may be formed separately as shown in the figure, or may be integrally formed by two-color molding. Reference numeral 7 denotes a metal holder, which holds the liquid crystal display 1 with a bent portion 8 at one end thereof, inserts a protruding portion 9 at the other end into an opening 10 provided in the printed circuit board 5, and bends it at the back side of the printed circuit board 5. Then, the liquid crystal display 1 and the like are fixed to the printed circuit board 5.

According to the above configuration, the light with strong directivity emitted from the light emitting diode chip 4 reaches the diffusion filter 3 as indicated by an arrow in the figure. Since the light reaching the diffusion filter 3 is strong near the optical axis center of the light emitting diode chip 4 and weak in other portions, the illumination of the diffusion filter 3 itself is uneven. When passing through the spread filter 3, the light is diffused in various directions as shown by the arrow by the diffusing action. The diffused light is sufficiently diffused by the space while reaching the semi-transmissive reflection plate 2, and illuminates the liquid crystal display 1 more uniformly from the back surface through the semi-transmission reflection plate 2. Note that the semi-transmissive reflector 2 also diffuses.

As is apparent from the above description, in the present invention, since the light is sufficiently diffused by the presence of the diffusion filter 3 and the space provided behind it, even if the light emitting diode having a strong directivity is used as the light source. The liquid crystal display 1 can be illuminated uniformly. This makes it possible to use a light emitting diode that generates less heat as a light source of a liquid crystal display.

Further, since the light emitting diode itself is smaller and cheaper than the lamp, the liquid crystal display device can be made thin and the cost can be reduced. Moreover, even if the display area of the liquid crystal display increases or decreases, it can be dealt with by simply increasing or decreasing the number of light emitting diodes, which makes it easy to standardize the lighting design.

[0016]

[Effect of device]

 The lighting structure of the present invention is capable of sufficiently diffusing the light from the light emitting diode with a simple structure, so that it is possible to uniformly illuminate the liquid crystal display using the light emitting diode as a light source, and avoid heat damage to surrounding parts. A lighting structure of a liquid crystal display, which is prevented and thinned, is realized.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment of an illumination structure of a liquid crystal display according to the present invention.

FIG. 2 is a cross-sectional plan view taken along the line AA of FIG.

FIG. 3 is a side sectional view of a conventional light guide plate edge light type illumination structure.

FIG. 4 is a side sectional view of a conventional housing type lighting structure.

[Explanation of symbols]

 1 ... Liquid crystal display 2 ... Semi-transmissive reflector 3 ... Diffusion filter 4 ... Light emitting diode 5 ... Printed board 6 ... Case 7 ... Holder

Claims (1)

[Scope of utility model registration request] 1. A liquid crystal display having a semi-transmissive reflection plate on a back surface thereof, a diffusion filter being arranged on the back surface of the semi-transmission reflection plate at an interval, and a light emitting diode as a light source on the back surface of the diffusion filter. A lighting structure for a liquid crystal display characterized by being arranged.