Surface light source device of side light type and liquid crystal display
A LCD comprises a surface light source device of side light type for auxiliary lighting. A fluorescent lamp is turned on to supply primary light to be introduced into a guide plate. A back face (upper face) of the guide plate provides a light control face including an emission promoting surface to promote emission from an illumination output face (lower face). The illumination output face provides a specular face without scattering power. Illumination light L 2 introduced into the guide plate escapes gradually from the back face and the illumination output face on the way of propagation.
1. A liquid crystal display comprising:
a liquid crystal layer;
a reflection plate disposed at a back side of said liquid crystal layer;
a first polarization plate interposed between said liquid crystal layer and said reflection plate;
a second polarization plate disposed at a front side of said liquid crystal layer; and,
a surface light source device of side light type for auxiliary lighting which comprises a guide plate and a primary light source to supply primary light to an incidence end face provided by a minor face of the guide plate, said guide plate having major faces to provide a back face and an illumination output face; wherein
said illumination output face is provided with no light scattering property;
said back face provides a light control face provided with emission promoting property which helps light propagating within the guide plate to be escaped from said illumination output face;
said guide plate being interposed between said liquid crystal layer and the first polarization plate so that said back face is directed to said liquid crystal layer.
2. A liquid crystal display in accordance with claim 1 , wherein said light control face is provided with a great number of fine regions to promote emission.
3. A liquid crystal display in accordance with claim 2 , wherein said fine regions are arranged with irregularity.
4. A liquid crystal display in accordance with claim 2 , wherein said fine regions are roughened partial regions in said back face.
5. A liquid crystal display in accordance with claim 3 , wherein said fine regions are roughened partial regions in said back face.