To prevent the disordering of an image and the generation of azimuth difference between the image and a touch panel by comprising a transparent sheet having a refraction factor larger than that of a peripheral medium, and outgoing the light introduced from a surface from a light source toward a rear face side.
The light (f) emitted from a light source 9 permeates a transparent sheet 8 to illuminate a liquid crystal display panel. The light source 9 preferably emits the P-polarization. It is impossible to introduce light to the whole face of the transparent sheet 8 with an incident angle equal to the Brewster αB even thought the light source 9 is used. By mounting the light source 9 just above one end of the transparent sheet 8, the light (f) from the light source 9 is introduced into a central portion of the transparent sheet 8 with the Brewster angle αB. For example, when a length of the transparent sheet 8 is 100 mm, and the refraction factor is 1.5, the Brewster angle αB is 56 degree, so that the light source 9 is mounted at a height of (100/2)/tan (56°)=33 mm from a surface of the transparent sheet.
AOYAMA SHIGERU
SHINOHARA MASAYUKI
