JPH09145936A - Panel for surface light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the appearance of a bright line nearby the end surface of a light-transmissive substrate, which is provided with a light source closely and has a high light transmissivity, and the darkening of both side parts by making the end surfaces uneven along their end sides. SOLUTION: In the surface light source panel provided with the light source 1 closely to the end surface 12 of the light-transmissive substrate 11 of acrylic resin, polycarbonate-based, resin, etc., with a high light transmissivity, the end surface 12 of the light-transmissive substrate 11 where the light source 1 is provided is formed unevenly in a zigzag or saw-tooth shape, etc., along the end side. Therefore, when the light emitted by the light source 1 enters the light-transmissive substrate 11 from the end surface 12 which is made uneven, this light is dispersed in various directions and made incident on the light- transmissive substrate 11. Consequently, the appearance of a light line called bright line nearby the end surface 12 of the light-transmissive substrate 11 is suppressed and there is no decrease in the luminance of both the side parts nearby the end surface 12, so that the uniformity is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light source panel used in various surface light source devices such as backlights for liquid crystal displays, display boards, and illumination displays, and more particularly to a light transmissive material having high light transmittance. The present invention relates to a surface light source panel in which a light source is provided close to the end surface of a flexible substrate.

2. Description of the Related Art Conventionally, in various surface light source devices such as backlights for liquid crystal displays, display boards, and illumination displays, light is transmitted through the entire surface of the surface light source device in order to emit light. A panel for a surface light source composed of a light-transmissive substrate having high property is used.

When light is emitted from the entire surface of the surface light source device using the surface light source panel as described above, as shown in FIG. 1, a transparent substrate 11 such as an acrylic plate having a high light transmittance. The light source 1 such as a cold-cathode tube is arranged close to one or both end faces 12 of the surface light source panel constituted by, and a reflecting mirror 1a is provided around the light source 1 to emit light from the light source 1. The light is guided into the transparent substrate 11.

On the other hand, when the light thus guided into the transparent substrate 11 is emitted from the emission surface 13, the end face 12 of the transparent substrate 11 on which the light source 1 is not provided is provided.
Further, the reflection sheet 2 is arranged on the reflection surface 14 on the side opposite to the emission surface 13 so that the light guided into the translucent substrate 11 is reflected by these reflection sheets 2.

Further, in the prior art, in order to emit light of uniform brightness from the entire surface of the above-mentioned surface light source panel, for example, as shown in FIG. A plurality of rows of circular diffused reflecting portions 15 are provided so that the area thereof increases as the distance from the light source 1 increases, and the light guided into the light-transmissive substrate 11 is provided in the diffused reflecting portions 15. Diffuse reflection is performed, or as shown in FIG. 1, a semitranslucent diffusion sheet 3 is provided on the emission surface 13, and the light emitted by the diffusion sheet 3 is diffused and made uniform. It was

Here, in the panel for surface light source as described above, the light emitted from the light source 1 is guided into the transparent substrate 11, and the light is emitted as described above from the emission surface 13 of the transparent substrate 11.
When the light is emitted from the light source 1, in the vicinity of the end face 12 of the light-transmissive substrate 11 in which the light source 1 is provided in close proximity, generally, the position is separated from the end face 12 by about 5 to 10 mm and further apart from this position by about several mm. At several positions, several bright lines called bright lines appear, and in the vicinity of the end face 12 of the transparent substrate 11 on which the light source 1 is provided,
The brightness on both sides was lower than other areas.

Therefore, when such a panel for a surface light source is used for a surface light source device such as a backlight of a liquid crystal display, the bright line makes the display of characters and images unclear, and the light source 1 is provided. There is a problem that both side portions near the end face 12 of the translucent substrate 11 are darkened, making it difficult to read these images.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a surface light source panel used for various surface light source devices such as a backlight for liquid crystal display, a display board, and an illumination display, which is close to the end face of the translucent substrate. It is an object of the present invention to solve the above-mentioned problems in the case where light emitted from a light source provided on the transparent substrate is guided into the transparent substrate and the light is emitted from the emission surface of the transparent substrate. It is a thing.

That is, according to the present invention, the light emitted from the light source provided in the vicinity of the end face of the transparent substrate as described above is guided into the transparent substrate, and the light is transmitted to the transparent substrate. When the light is emitted from the emission surface, a bright line called a bright line appears near the end surface of the transparent substrate on which the light source is provided, or both side portions near the end surface of the transparent substrate on which the light source is provided. It is suitable for use in these surface light source devices without suppressing the difficulty of reading characters and images when used in surface light source devices such as backlights for liquid crystal displays by suppressing the occurrence of darkness. It is an object of the present invention to provide a panel for a surface light source.

[0009]

In the surface light source panel according to the present invention, in order to solve the above problems, the light source 1 is provided in the vicinity of the end surface 12 of the translucent substrate 11 having a high light transmittance. Of a surface light source panel to be used
The end face 12 of the translucent substrate 11 provided with is formed in a concavo-convex shape along the end side direction.

Here, it is preferable to use, as the light-transmissive substrate 11 constituting the surface light source panel of the present invention, a light-transmissive substrate 11 made of a material having a good light transmission property such as an acrylic resin or a polycarbonate resin. .

Further, in the surface light source panel according to the present invention, when the end face 12 of the light-transmissive substrate 11 provided in the vicinity of the light source 1 is formed in a concavo-convex shape along the edge side direction, the concavo-convex shape is The shape is not particularly limited, and for example, it can be formed in a zigzag shape, a wavy shape, a sawtooth shape, or the like.

In the case of manufacturing a surface light source panel in which the end face 12 of the light-transmissive substrate 11 provided with the light source 1 in close proximity as described above is formed in a concavo-convex shape along the end side direction,
In order to stably and easily manufacture such a panel for a surface light source, a metal used for molding the panel for a surface light source so as to correspond to the unevenness on the end surface 12 of the transparent substrate 11. The end surface of the mold is formed in a concavo-convex shape, and the end surface 12 of the translucent substrate 11 is formed at the same time when the surface light source panel is formed.
Is preferably formed in an uneven shape.

Then, as in the surface light source panel according to the present invention, when the end face 12 of the transparent substrate 11 on which the light source 1 is provided is formed in a concavo-convex shape along the edge side direction, the light is emitted from the light source 1. When light is incident on the translucent substrate 11 from the end surface 12 formed in a concavo-convex shape, the light is dispersed in various directions and is incident on the translucent substrate 11. It is possible to suppress the generation of a bright line called a bright line in the vicinity of the end surface 12 of the translucent substrate 11 provided with the light source 1 as in the conventional case, and to end the end surface 12 of the translucent substrate 11 provided with the light source 1. It is considered that the uniformity is improved without lowering the brightness of both sides in the vicinity of.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a surface light source panel according to the present invention will be specifically described below with reference to the accompanying drawings.

In the surface light source panel of this embodiment, an acrylic plate made of polymethylmethacrylate resin is used for the translucent substrate 11 having high translucency.
As shown in FIG. 3, in this translucent substrate 11, one end face 12 provided with the light source 1 such as a cold cathode tube in close proximity is formed in a zigzag uneven shape along the edge side direction. There is.

Also in the surface light source panel of this embodiment, as shown in FIG. 4, the light source 1 is placed close to one end face 12 of the translucent substrate 11 formed in the uneven shape as described above. Along with the provision of the reflecting mirror 1a around the light source 1, the light emitted from the light source 1 is guided into the light-transmissive substrate 11 from the zigzag end face 12 along the edge direction as described above. I am trying.

In the surface light source panel of this embodiment, when the light guided into the translucent substrate 11 as described above is emitted from the emission surface 13, the light source 1 is formed as described above.
End face 1 other than the end face 12 formed in a concave-convex shape
2 and the reflection sheet 2 on the reflection surface 14 on the side opposite to the emission surface 13 are arranged so that the light guided into the translucent substrate 11 is reflected by these reflection sheets 2.

Also, in the surface light source panel of this embodiment as well, in order to emit light of uniform brightness from the entire emission surface 13 of the surface light source panel, like the conventional surface light source panel. , As shown in FIG.
4 is provided with a plurality of rows of irregular reflection portions 15 provided with circular irregular reflection portions 15 that diffusely reflect light so that the area thereof increases as the distance from the light source 1 increases. The diffused light is diffused on the emission surface 13 of the diffused light.
Is provided, and the light emitted by the diffusion sheet 3 is diffused and made uniform.

Using the surface light source panel according to this embodiment, the light source 1 provided close to one end surface 12 of the translucent substrate 11 formed in the uneven shape as described above.
When the light emitted from is guided into the light-transmissive substrate 11, the light is dispersed in various directions on the end surface 12 formed in a concavo-convex shape and enters the light-transmissive substrate 11. , The light thus entered is reflected by the irregular reflection section 12 described above.
And other portions of the reflection sheet 2 are reflected, and the emission surface 13
The light guided to the laser light is emitted through the semi-transparent diffusion sheet 3, and a bright line called a bright line is formed near the end face 12 of the transparent substrate 11 on which the light source 1 is provided as in the conventional case. The light having uniform brightness is emitted on the entire emission surface 13 without causing any occurrence or reduction in brightness of both side portions in the vicinity of the end surface 12 of the translucent substrate 11 provided with the light source 1. Become.

Next, in the surface light source panel according to the above-described embodiment, when the end surface 12 of the light-transmissive substrate 11 provided in the vicinity of the light source 1 is formed in a zigzag shape along the end side direction, its pitch is set. 2 mm, and the surface light source panel of the embodiment in which the height difference between peaks and valleys is 1 mm, and the end face 12 of the translucent substrate 11 on which the light source 1 is provided in close proximity is not formed into a zigzag shape. As shown, the surface light source panel of the comparative example in which the end face 12 was formed flat was used, and the state of light emitted from each emission surface 13 was examined under the same conditions.

Here, in examining the state of the light emitted from the emission surface 13 of each of the surface light source panels of the example and the comparative example, each emission surface 13 is divided into 5 parts in the vertical and horizontal directions, and 25 parts are obtained. Divide into parts, focus on the position of the center of each part, measure the brightness in each part, find the average value (average brightness) of the brightness measured in each part, and set the maximum among the above parts. And the minimum luminance are measured, the ratio of the minimum luminance to the maximum luminance (uniformity) is obtained, and the presence or absence of a bright line in the vicinity of the end face 12 of the translucent substrate 11 provided with the light source 1 is visually inspected. Are shown in Table 1 below. Regarding the presence or absence of the bright line, the case where the bright line was not confirmed was indicated by ◯, and the case where the bright line was visible was indicated by x.

[0022]

[Table 1]

As is apparent from this result, the surface light source panel of the embodiment in which the end face 12 of the light-transmissive substrate 11 provided in the vicinity of the light source 1 is formed in a zigzag shape along the edge side direction thereof, The average luminance and the uniformity are improved as compared with the surface light source panel of the comparative example in which the end face 12 is flat, and no bright line is generated in the vicinity of the end face 12 of the transparent substrate 11 on which the light source 1 is provided. The entire emission surface 13 can be illuminated uniformly and with sufficient brightness.

[0024]

As described above in detail, in the surface light source panel according to the present invention, since the end face of the translucent substrate on which the light source is provided is formed in a concavo-convex shape along the end side direction, the light is emitted from the light source. When the incident light is incident on the translucent substrate from the end surface formed in the uneven shape, the light is dispersed in various directions and incident on the translucent substrate.
As a result, a bright line called a bright line is generated in the vicinity of the end surface of the transparent substrate provided with the light source as in the conventional case, and the brightness of both side portions near the end surface of the transparent substrate provided with the light source is low. However, light having a uniform and sufficient luminance has come to be emitted from the entire emission surface of the surface light source panel.

As a result, when the surface light source panel according to the present invention is used in a surface light source device such as a backlight of a liquid crystal display, as in the conventional case, the surface light source is provided in the vicinity of the end surface of the transparent substrate provided with the light source. Suitable for these surface light source devices without causing a bright line or lowering the brightness of both side portions near the end surface of the translucent substrate provided with a light source, which makes it difficult to read characters and images. Can be used for.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional explanatory view of a surface light source device using a conventional surface light source panel.

FIG. 2 is a schematic explanatory view showing a conventional surface light source panel in which a diffuse reflection portion is provided on a reflection surface of a translucent substrate opposite to an emission surface thereof.

FIG. 3 is a schematic explanatory diagram of a surface light source device using the surface light source panel according to the embodiment of the present invention.

FIG. 4 is a schematic cross-sectional explanatory view of a surface light source device using the surface light source panel of this embodiment.

[Explanation of symbols]

 1 light source 11 translucent substrate 12 end face of translucent substrate

Front Page Continuation (72) Inventor Kenji Kimishima 1-71 Tokuan 1-71 Tokuan, Tsurumi-ku, Osaka City, Osaka Prefecture Starlight Industry Co., Ltd.

Claims (1)

[Claims] 1. An end surface 1 of a translucent substrate 11 having high light transmissivity.
In the surface light source panel in which the light source 1 is provided in the vicinity of 2, the end surface 12 of the translucent substrate 11 in which the light source 1 is provided.
A panel for a surface light source, wherein the panel is formed in a concavo-convex shape along the edge direction.