| 摘要 |
PURPOSE:To prevent the formation of spectral light strips which are likely to be produced at peripheral parts when a Fresnel lens sheet is used for a transmission type screen and enhance the quality of reproduced plane images by forming the rising faces of the Fresnel lens into polyhedral constitution so that the respective angles of intersection of the plural faces differ each other. CONSTITUTION:The rising faces 10 of a Fresnel lens 1 are formed into polyhedral constitution in such a manner that the respective angles 16 of intersection of the plural faces differ each other. Then, when the Fresnel lens is used for a renticular lens sheet as a constituting element for a transmission type screen, a rear projection television device combined with a diffusion layer, etc., the images are well visible when viewed from diagonally, too. |
