| 摘要 |
PURPOSE:To provide a light transmission plate which is used for display boards of an electrical illumination system, electrical illumination advertisements, back lights, etc., and is reduced in its cost by increasing the yield at the time of production and decreasing variations and is formable as a thin type by light diffusion layers having high brightness and high resolution. CONSTITUTION:After a thermal strain latent image is formed on light transmissive plastic, the light diffusion reflection layers 2 consisting of the microjoints assembled with large cracks 3 and small cracks 4 are formed in the part of the thermal strain latent image by a treatment of immersing the plastic into a rich solvent and lean solvent and drying the plastic. The parts exclusive of the thermal strain latent image are not coated with coating films having the resistance to the rich solvent and the lean solvent so that these parts are not treated. The light diffusion reflection layers 2 are formed as the high- resolution patterns. |
