Planar illumination device and liquid crystal display device using the same

Abstract

A planar illumination device for illuminating a liquid crystal display panel provided with a polarizing plate on a light incident side, includes: a light source unit for emitting light having a specified polarization direction; and a light irradiating member for deflecting light emitted from the light source unit and irradiating the liquid crystal display panel with the deflected light, wherein the light irradiating member deflects the light emitted from the light source unit such that the polarization direction of the light emitted from the light source unit substantially coincides with a transmission axis direction of the polarizing plate of the liquid crystal display panel.

1 . A planar illumination device that illuminates a liquid crystal display panel, comprising:
 a light source unit that emits light toward the liquid crystal display panel;   an optical element that is disposed on an optical path of the light emitted from the light source unit; and   a driver that drives the optical element, wherein   the driver drives the optical element to control a direction of the light that illuminates the liquid crystal display panel.   
     
     
         2 . The planar illumination device according to  claim 1 , wherein
 the optical element includes a lens, and   the driver moves a position of the lens to control the direction of the light that illuminates the liquid crystal display panel.   
     
     
         3 . The planar illumination device according to  claim 2 , wherein the optical element includes a lens array as the lens. 
     
     
         4 . The planar illumination device according to  claim 1 , wherein
 the optical element includes a mirror, and   the driver rotates the mirror to change an incident angle of light incident on the mirror to control the direction of the light that illuminates the liquid crystal display panel.   
     
     
         5 . The planar illumination device according to  claim 1 , further comprising a human detection sensor that detects a position of a user, wherein
 the driver drives the optical element based on a detection result of the human detection sensor to control the direction of the light that illuminates the liquid crystal display panel.   
     
     
         6 . The planar illumination device according to  claim 1 , wherein the light source unit includes a plurality of LED devices which are arranged side by side. 
     
     
         7 . A liquid crystal display device, comprising:
 the planar illumination device according to  claim 1 ; and   a liquid crystal display panel that is illuminated by the planar illumination device.