Planar light source

Abstract

A planar light source has a light emitting source, and a light guide plate for receiving light beams emitted from the light emitting source at a front side thereof and changing direction of the light beams, discharging the light beams from an upper surface thereof. A first anisotropic diffusion surface is formed on a lower surface of the light guide plate, and a reflection member is provided on the first anisotropic diffusion surface. The first anisotropic diffusion surface is a hologram diffusion surface or a hairline diffusion surface.

1 . A planar light source comprising: 
 a light emitting source;    a light guide plate for receiving light beams emitted from the light emitting source at a front side thereof and changing direction of the light beams, discharging the light beams from an upper surface thereof;    a first anisotropic diffusion surface formed on a lower surface of the light guide plate; and    a reflection member provided to face the lower surface of the light guide plate on which the first anisotropic diffusion surface is formed.    
   
   
       2 . The planar light source according to  claim 1  wherein the reflection member is provided for reflecting the light beams emitted from the first anisotropic diffusion surface to return the light beams to the first anisotropic diffusion surface to form anisotropic diffused light beams which are increased in sectional area by two diffusion.  
   
   
       3 . The planar light source according to  claim 1  wherein the first anisotropic diffusion surface is a hologram diffusion surface.  
   
   
       4 . The planar light source according to  claim 1  wherein the first anisotropic diffusion surface is a hairline diffusion surface.  
   
   
       5 . The planar light source according to  claim 1  wherein a plurality of prisms are formed on the upper surface of the light guide plate.  
   
   
       6 . The planar light source according to  claim 1  wherein the angle between the upper surface and the front side of the light guide plate is 90 degrees, and the thickness of the light guide plate is gradually reduced toward a rear side, and the first anisotropic diffusion surface is formed on the lower surface.  
   
   
       7 . The planar light source according to  claim 6  further comprising a second anisotropic diffusion surface formed on a part of the upper surface of the light guide plate.  
   
   
       8 . The planar light source according to  claim 1  wherein the first anisotropic diffusion surface comprises two kinds of anisotropic diffusion surfaces which are different from each other in characteristic of diffusion.  
   
   
       9 . The planar light source according to  claim 1  further comprising a diffusion plate and light direction correcting means provided on the light guide plate.  
   
   
       10 . The planar light source according to  claim 9  wherein the light direction correcting means comprises a Px prism sheet having X-direction prisms and a Py prism sheet having Y-direction prisms.