FRESNEL LENS SHEET AND TRANSMITTING TYPE SCREEN

摘要

PROBLEM TO BE SOLVED: To provide a Fresnel lens sheet that prevents deterioration of contrast due to external light from above such as indoor lighting and also to provide a transmitting type screen equipped with the Fresnel lens sheet. SOLUTION: This is a Fresnel lens sheet 14 for a transmitting type screen having a Fresnel lens element 21 on the viewer's side. In a part of at least the upper half of the surface on the projection light source side of the sheet 14, there is formed a total reflection preventive lens element 25 that reduces an angleθ1 between the external light 23 made incident from the viewer's side through the Fresnel lens element 21 and the lens surface 24 on the projection light source side smaller than the critical angleθ2 of the external light 23. The total reflection preventive lens element is preferably a linear Fresnel lens with a fixed angled lens surface or with a concave lens shape. COPYRIGHT: (C)2005,JPO&NCIPI