JPH1026757A - Illuminator for display device of edge light system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To weaken irradiating light at a part close to a light source and to improve the irregularity of luminance by disposing a specified level difference part in a frame body. SOLUTION: Ordinarily, a part closer to the light source 2 is irradiated stronger with the light passing through reflectors 4 to 6 from the light source 2 and irradiating a diffusing plate 7, so that the part close to the light source 2 is bright and the irregularity of luminance is caused as an illuminator. As for the reflectors; the 2nd reflector 6 in parallel with the plate 7 or a liquid crystal panel, the level difference part 1c, the parallel plane reflection part 4b of the 1st reflector 4, and the inclined surface reflection part 4a of the reflector 4 whose distance from the plate 7 or the liquid crystal panel becomes short as it goes away from the light source are disposed in order from the light source 2. By forming the level difference part 1c between the reflector 6 and the reflection part 4b of the reflector 4 and making the distance of the reflector 4 from the plate 7 or the liquid crystal panel long, the light from the light source 2 reflected from the reflector 6 and irradiating the part of the plate 7 close to the light source 2 is weakened and the irregularity of luminance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge light type display device capable of providing uniform illumination by improving brightness unevenness used for a backlight of a display device such as a liquid crystal display device, in particular, brightness unevenness near a light source. It relates to a lighting device.

[0002]

2. Description of the Related Art A display device using a liquid crystal display element is widely used in a word processor, a personal computer, a television, and the like. A lighting device is required for clear display. Therefore, in this type of conventional apparatus, for example, Japanese Patent Application Laid-Open
There is a proposal as disclosed in 9980 gazette. FIG. 5 shows an example of the illumination device disclosed in Japanese Patent Application Laid-Open No. 61-21980. In this illuminating device, a transparent plastic or glass plate 32 having good light transmittance, which is a transparent plastic or glass plate coated with a fluorescent material 31 on the back surface of a liquid crystal panel 30, is arranged in close proximity, and ultraviolet light from a light source 33 reflects on a reflective plate 34 which is inclined. And irradiates the liquid crystal panel with the diffused light of visible light obtained from the phosphor. Further, the ultraviolet rays behind the light source 33 are guided forward by the reflection plate 35. However, in this illuminating device, the illuminating light (ultraviolet light) from the light source irradiates the fluorescent material near the light source directly or via the reflector, so that the illumination in the vicinity of the light source becomes bright and causes uneven brightness. There was a disadvantage.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and is intended to eliminate uneven brightness of light emitted from a light source, particularly near the light source.
An object of the present invention is to provide an illumination device for an edge light type display device capable of uniform illumination.

[0004]

In order to achieve the above object, according to the present invention, there is provided an illumination device for an edge light type display device having a frame for accommodating a light source. And a first portion on a side farther from the light source that reflects mainly forward illumination of the light source.
A reflecting portion, a second reflecting portion closer to the light source, and a third reflecting portion for reflecting mainly rearward irradiation of the light source, wherein the second reflecting portion has a distance from the display panel of the display device equal to the first distance.
A step portion is disposed on the frame so as to be larger than the reflection portion.

Further, according to the present invention, the first reflecting portion has at least an inclined surface, and the second reflecting portion has a parallel surface with respect to the display panel. Are arranged so that the distance between the two is reduced.

Further, in the illumination device for an edge light type display device according to the present invention, the light source accommodating portion has an irradiation cover portion for suppressing the light source from directly irradiating an upper portion near the light source. It is characterized by having.

Further, according to the present invention, the second reflecting portion is formed of a reflecting plate, one end of which is provided at a lower end of the light source storage portion of the frame, and the other end of which is provided with the first reflecting portion. It is provided on the back surface, and the step portion is formed between the first reflection portion and the second reflection portion.

Further, in the present invention, the second reflecting portion is formed integrally with the frame together with the first reflecting portion and the step portion, and the second reflecting portion is formed on the frame. It is characterized by:

Further, in the illumination device for an edge light type display device according to the present invention, at least two light source housing portions are provided in the frame.

Further, the present invention is characterized in that the first reflecting portion is formed of a reflecting sheet, and one end of the first reflecting portion is disposed on the frame body except for an eave-like portion covering the step portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on embodiments shown in the drawings. FIG. 1 is a perspective view showing a main part of an illumination device for an edge light type display device according to a first embodiment of the present invention, and FIG. 2 is a sectional view of a main part of the first embodiment of the present invention. 1 and 2, the frame 1
Is an ABS material, a PS (vinyl chloride) material or a PC (polycarbonate) material or the like, and is integrally formed of a resin material, and is a light source housing portion 3 for housing a light source 2 such as a fluorescent tube, and a first reflection portion acting as a first reflection portion. The light was reflected from the mounting portions 1a and 1b of the body 4, the mounting portion 1d of the third reflector 5 acting as the third reflector, and the mounting portions 1e and 1f of the second reflector 6 acting as the second reflector. Attachment part 1 of diffusion plate 7 for diffusing irradiation light
h, a mounting portion 1i for the liquid crystal panel 8 is provided. The liquid crystal panel 8 is a display panel of a display device, and is mounted on the diffusion plate 7 in parallel with the diffusion plate 7.

The mounting portion of the first reflector 4 has a parallel surface mounting portion 1b and an inclined surface mounting portion 1a with respect to the diffusion plate 7 or the liquid crystal panel 8.
The inclined surface mounting portion 1a is disposed so that the distance from the light source 2 to the diffusion plate 7 or the liquid crystal panel 8 decreases as the distance from the light source 2 increases. A reflection sheet is used as the first reflector 4, and the inclined surface mounting portion 1a and the parallel surface mounting portion 1 of the first reflector 4 are used.
b, the reflection surfaces of the parallel surface reflection portion 4b and the inclined surface reflection portion 4a are formed. In this embodiment, the angle of the inclined surface mounting portion 1a is preferably about 25 degrees with respect to the parallel surface mounting portion 1b. A mounting portion 1d of the third reflector 5 for reflecting mainly rearward irradiation of the light source 2 is a curved surface portion of the light source storage portion 3 of the frame 1, and the third reflector 5 is provided with a reflecting sheet on the curved surface. Are bonded. As the reflection sheet, for example, an aluminum vapor-deposited film of polyester or a sheet having a light reflection function by coloring white is suitable. As the first reflector 4 and the third reflector 5, silver or aluminum is vapor-deposited directly on each mounting portion of the frame 1 instead of the reflection sheet, or a white or silver pigment or dye is applied. Thus, a reflection surface can be formed.

The second reflector 6 is formed of a reflector, one end of which is located at the lower end 1e of the frame 1 having the light source housing 3, and the other end of which is the first reflector.
A step 1c is formed between the upper surface of the first reflector 4 and the upper surface of the second reflector 6, which is provided on the back surface 1f of the frame 1 to which the reflector 4 is attached. As a reflector of the second reflector 6, a reflective sheet is adhered to the upper surface of a flat plate serving as a base, silver or aluminum is directly deposited, or a white or silver pigment or dye is applied to reflect. A surface can be formed. Further, if a metal plate is used as the base as the second reflector 6, there is an effect that electromagnetic noise generated from the light source can be shielded by the metal plate. The diffusion plate 7 is attached to the attachment portion 1h of the frame 1. As the diffusion plate 7, an acrylic plate made of milky white or translucent is used. Further, the diffusion plate can be appropriately replaced with a prism plate or the like depending on the purpose.

The light source housing 3 of the frame 1 extends the light source housing of the frame 1 so as to cover the light source 2 in order to prevent the light source 2 from directly irradiating the portion of the diffusion plate 7 near the light source. And has a curved irradiation cover portion 1g. Irradiation cover 1g
Thus, irradiation light upward from the light source 2 can be blocked.

The present invention is configured as described above, and its operation will be described below. Irradiation light from the light source 2 is mainly emitted to the rear of the light source 2, reflected by the third reflector 5 and guided to the front of the light source 2, and mainly emitted to the front of the light source 2 is reflected by the first reflector 4. Then, the liquid crystal panel is illuminated as diffused light reflected by the second reflector 6 and diffused by the diffuser 7.

In this case, the light that normally irradiates the diffuser from the light source 2 via the reflector is radiated more strongly nearer the light source.
As a lighting device, a portion near the light source is bright, and luminance unevenness occurs. Therefore, in the first embodiment, the reflectors are arranged in order from the light source 2, the second reflector 6 parallel to the diffusion plate 7 or the liquid crystal panel 8, the stepped portion 1 c, and the parallel plane reflector of the first reflector 4. 4b, an inclined surface reflection portion 4a of the first reflector 4 is provided in which the distance from the diffusion plate 7 or the liquid crystal panel decreases as the distance from the light source increases, and the second reflector 6 is parallel to the first reflector 4. By providing a step portion 1c between the light source 2 and the surface reflection portion 4b to increase the distance between the diffusion plate 7 and the liquid crystal panel, the light is reflected by the second reflector of the light source 2 and the light source of the diffusion plate 7, that is, the liquid crystal panel 8 The light irradiating near 2 can be reduced to improve the luminance unevenness.

Further, by providing the irradiation cover 1g of the light source 2 on the frame 1 of the light source housing 3, the light source 2
In order to suppress direct irradiation of the portion near the light source, the light irradiated near the light source 2 is weakened, and the luminance unevenness can be further improved. Further, by making the reflectance of the second reflector lower than that of the first reflector, it is also possible to reduce the light radiated near the light source 2 and to improve the luminance unevenness. Furthermore,
The first reflector 4 is formed of a reflection sheet, and is attached to the frame while leaving one end of the first reflector 4 as an eaves-like portion 4c covering the step portion 1c, whereby brightness unevenness due to irradiation light reflected from an end surface of the step portion 1c is provided. Can be prevented.

FIG. 3 is a sectional view showing a main part of a second embodiment of the present invention. 1 and 2 showing the first embodiment have the same configuration and the same action in FIG. In the second embodiment shown in FIG. 3, the base of the second reflector 9 is formed integrally with the base of the first reflector 4 and the frame 1 together with the step portion 1c, and the reflector is formed thereon. It is. The reflection portion is formed by bonding a reflection sheet, directly depositing silver or aluminum, or applying a white or silver pigment or dye in the same manner as the first reflector 4 of the first embodiment. A surface can be formed. By integrally forming the frame including the base of all the reflectors, it is possible to eliminate the work of attaching the second reflector,
Further, the strength of the frame can be increased.

FIG. 4 is a sectional view showing a main part of a third embodiment of the present invention. In the third embodiment shown in FIG. 4, two light source housings 13 and 1 are provided on both edge sides of the frame 10.
4, the light sources 11 and 12 are arranged, and the first reflecting portions 15 and 16, the second reflecting portions 17 and 18, and the step portion 10 are provided.
a and 10b are provided symmetrically. Therefore, the first
The reflecting portions 15 and 16 are configured such that the center of the two light sources 11 and 12 is the highest and is inclined toward each light source. In consideration of the fact that the illumination from the light source becomes weaker as the distance from the light source increases, the distance from the diffusion plate decreases toward the center. A third reflector 19 at the rear of the light sources 11, 12;
20 and the eaves 10c, 10d have the same configuration as in the first and second embodiments. The formation of each reflecting portion can be performed in the same manner as in the second embodiment. In the third embodiment, as compared with the first and second embodiments, the light sources are provided at both edges of the lighting device, so that the illumination from the light source to the display panel becomes more uniform and the luminance unevenness is further improved. Can be. In each of the above-described embodiments, the first, second, and third reflectors are formed on the frame by bonding a reflection sheet or applying a pigment or the like. By molding the frame with a resin material, the function of each reflector can be imparted to the frame itself. In particular, the second and third reflectors are preferable because there is no problem even if the reflectance is lower than that of the first reflector.

[0020]

As is apparent from the above description, according to the present invention, the distance between the second reflector closer to the light source and the display panel of the display device is greater than that of the first reflector closer to the light source. By arranging the step portion in the frame so as to increase the size, it is possible to reduce the irradiation light in a portion close to the light source and to improve the luminance unevenness.

Further, an illumination cover portion is provided in the light source storage portion to suppress the light source from directly irradiating an area above the vicinity of the light source on the display panel of the display device. Can be improved.

Further effects can be obtained by using the above-mentioned step portion and the irradiation cover portion together.

[Brief description of the drawings]

FIG. 1 is a perspective view of an essential part showing a first embodiment of an illumination device for an edge light type display device according to the present invention.

FIG. 2 is a sectional view of a main part showing a first embodiment of the present invention.

FIG. 3 is a sectional view of a main part showing a second embodiment of the present invention.

FIG. 4 is a sectional view of a main part showing a third embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a conventional illumination device for an edge light type display device.

[Explanation of symbols]

 1, 10 Frame 1a Inclined surface attachment portion of first reflector 4 1b Parallel surface attachment portion of first reflector 4 1c, 10a, 10b Stepped portion 1g, 10c, 10d Irradiation cover portion 2, 11, 12 Light source 3, 13, 14 Light source housing 4, 15, 16 First reflector 5, 19, 20 Third reflector 6, 9, 17, 18 Second reflector 7 Diffusing plate 8 Liquid crystal panel

Claims (7)

[Claims] 1. An illumination device for an edge light type display device having a frame for accommodating a light source, wherein the frame includes a light source accommodating portion and a reflecting portion, and the reflecting portion mainly irradiates the light source in front of the light source. A first reflector on a side farther from the light source to be reflected, a second reflector on a side closer to the light source, and a third reflector for reflecting mainly rearward illumination of the light source, wherein the second reflector is a display of a display device. An illumination device for an edge light type display device, wherein a step portion is disposed on the frame so that a distance from the panel is greater than the first reflection portion. 2. The display panel according to claim 1, wherein the first reflecting portion has at least an inclined surface, and the second reflecting portion has a parallel surface. The distance between the inclined surface and the display panel decreases as the distance from the light source increases. 2. The illumination device for an edge light type display device according to claim 1, wherein the illumination device is arranged so as to be as follows. 3. The edge according to claim 1, wherein the light source storage portion has an irradiation cover portion for suppressing the light source from directly irradiating an upper portion near the light source. Light-type display device lighting device. 4. The second reflection portion is formed of a reflection plate, one end of which is disposed on a lower end of the light source storage portion of the frame, and the other end is disposed on a back surface of the frame on which the first reflection portion is mounted. And
The illumination device for an edge light type display device according to claim 1, wherein the step portion is formed between the first reflection portion and the second reflection portion. 5. The apparatus according to claim 1, wherein the second reflecting section is formed integrally with the frame body together with the first reflecting section and the step section, and the second reflecting section is formed on the frame body. An illumination device for an edge light type display device according to claim 1, 2 or 3. 6. The illumination device for an edge light type display device according to claim 1, wherein at least two of said light source storage portions are provided in said frame body. 7. The first reflection section is made of a reflection sheet,
The illumination device for an edge light type display device according to any one of claims 1 to 6, wherein one end of the display device is disposed on the frame body leaving an eave-shaped portion covering the step portion.