JPH09147615A - Surface light emitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently guide a light made incident on a light transmission plate to the upper surface of the light transmission plate with a simple structure so as to increase upper surface luminance by forming a plurality of grooves in the upper or lower surface of the light transmission plate and gradually increasing the depths of the grooves toward a spot farther away from a light source. SOLUTION: When a light source 3 is turned ON, a portion of a light emitted from the light source 3 and made incident on a light transmission plate 2 is directly supplied to an upper surface 22 and a lower surface 23 or a side face and reflected or emitted to the outside of the plate 2. A portion of the light made incident on the plate 2 is supplied directly or indirectly to a most shallow groove 41 nearest to the light source 3, a subsequent second most shallow groove 42 and a deepest groove 45 farthest from the light source, a part thereof are reflected upward in sequence and emitted from the upper surface 22 to the outside of the plate 2. Thus, the total reflection light quantity of the grooves 41 to 45 are made approximately uniform and the luminance of the upper surface of the plate 2 is made uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light emitting device that can be used as a backlight of a display.

[0002]

2. Description of the Related Art A surface light emitting device used for a backlight of a display is constructed by arranging a light source composed of an LED or the like on a side surface of a transparent light guide plate. Then, in order to guide the light incident on the light guide plate from the light source to the upper surface of the light guide plate, minute unevenness is formed on the lower surface of the light guide plate by graining or the like. However, since the light from the light source cannot be sufficiently reflected by the minute unevenness due to such texture processing, the upper surface luminance of the light guide plate cannot be sufficiently increased.

[0003]

SUMMARY OF THE INVENTION The main object of the present invention is to efficiently guide the light incident on the light guide plate to the upper surface of the light guide plate with a simple structure to increase the brightness of the upper surface of the light guide plate.

[0004]

SUMMARY OF THE INVENTION The present invention provides a surface light-emitting device comprising a light guide plate and a light source arranged on the side surface of the light guide plate, wherein a plurality of grooves are formed on the upper surface or the lower surface of the light guide plate. The groove is characterized in that its depth increases as the distance from the light source increases.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. The surface light emitter 1 is mainly configured by a light guide plate 2 and a light source 3 that is disposed face-to-face with at least one side surface (front side surface 21) of the light guide plate 2.

The light guide plate 2 is formed by using a transparent resin having a high light transmissivity, for example, a flat plate made of acrylic, and its planar shape is formed into a desired shape, for example, a rectangle or a square, depending on the application. On the lower surface 23 of the light guide plate 2, a plurality of grooves 4 linearly extending in the left-right direction are formed so that the depth thereof gradually increases as the distance from the light source 3 increases. Each of the grooves 41, 42, ... 45 has a predetermined inclination (around 45 degrees) with respect to the lower surface 23 so as to reflect the light of the light source 3 toward the upper surface 22 of the light guide plate 2. Each groove 41, 42, ...
The intervals of 45 are formed at substantially equal intervals. Therefore, the interval may be gradually changed (for example, decreased or increased). Each groove 41, 4
It is preferable to form minute irregularities on the surface of 2, ... 45 so as to enhance the light diffusion effect. be able to. Then, in order to simplify the structure and to achieve the light diffusion effect, only the air layer is present in the groove 4 without providing any other material.

A light source 3 arranged on the front side surface 21 of the light guide plate 2.
Can be configured to use one point light source such as an LED, but a configuration using a plurality of point light sources such as LEDs, or a configuration using a linear light source such as a cold cathode tube, This is preferable in order to make the brightness of the upper surface 22 of the light guide plate uniform.

In the above structure, when the light source 3 is turned on, a part of the light emitted from the light source 3 and incident on the light guide plate 2 directly reaches the upper surface 22, the lower surface 23 or the side surface and is reflected there. The light is emitted to the outside of the light guide plate 2. Part of the light incident on the light guide plate 2 is closest to the light source 3 and is the shallowest groove 4.
1. The next shallowest groove 42 behind it ... Directly or indirectly reaches the farthest and deepest groove 45 from the light source 3, and a part thereof is sequentially reflected upward as indicated by the arrow to the upper surface. Two
Since the light is emitted from the light guide plate 2 to the outside of the light guide plate 2, the light incident on the light guide plate 2 can be efficiently guided to the upper surface 22 of the light guide plate 2, and the upper surface brightness of the light guide plate 2 can be increased.

Here, the light amount of the light source 3 reaching the groove 4 is large on the side closer to the light source 3 and decreases as the distance from the light source increases, but the depth of the groove 4 increases as the distance from the light source 3 increases, and Since the reflection area is increased, the total amount of light reflected by the grooves 41, 42, ... 45 can be made substantially uniform, and the brightness of the upper surface of the light guide plate 2 can be made uniform. Further, the light reflected by the groove 4 and the light passing through the groove 4 are uniformly diffused due to the unevenness of the surface of the groove 4, the presence of an air layer in the groove 4, and the like, so that the brightness of the upper surface 22 of the light guide plate is made more uniform. Can be made.

In the above embodiment, a plurality of grooves 4 are formed on the lower surface 23 of the light guide plate 2, but as shown in FIG. 2, a plurality of grooves 4 are formed on the upper surface 22 of the light guide plate 2 in the same manner as described above. The groove 4 can also be formed. In addition, the light guide plate 2 shown in FIG.
By forming a plurality of grooves 4 on the upper surface 22 of the lower surface 23 in a predetermined relationship with the grooves 41, 42, ... It is also possible to form a plurality of grooves on the upper and lower surfaces of which the depth gradually increases as the distance from the light source 3 increases. Further, a reflecting member that enhances the light reflecting function may be provided on the lower surface 23 or the side surface of the light guide plate 2 as needed.

[0011]

As described above, according to the present invention, a plurality of grooves are formed on the upper surface or the lower surface of the light guide plate, and a simple structure in which the depth of these grooves increases with the distance from the light source is used. The light incident on the light guide plate can be efficiently guided to the upper surface of the light guide plate, and the brightness of the upper surface of the light guide plate can be increased.

[Brief description of the drawings]

FIG. 1 is a side view of a surface light emitting device showing an embodiment of the present invention.

FIG. 2 is a side view of a surface emitting device showing another embodiment of the present invention.

[Explanation of symbols]

 1 surface emitting device 2 light guide plate 3 light source 4 groove

Claims (1)

[Claims] 1. A surface light emitter comprising a light guide plate and a light source arranged on a side surface of the light guide plate, wherein a plurality of grooves are formed on an upper surface or a lower surface of the light guide plate, and the groove has a depth of A surface-emitting device having a structure that increases as the distance from the light source increases.