| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission type screen preventing the deterioration of contrast due to external light rays such as indoor illumination. SOLUTION: The transmission type screen comprises a Fresnel lens sheet formed with a Fresnel lens element on the surface of observer side and a light shielding sheet 13 arranged on the observer side of the Fresnel lens sheet. Light shielding elements 22 absorbing the external light ray which undergoes total reflection on the surface of projection light source side of the Fresnel lens sheet among the external light rays 2 made incident from the observer side and exits the light rays to the observer side are formed on the light shielding sheet 13 and, thereby, the deterioration of contrast due to external light rays is prevented. Therein, it is preferable that the light shielding elements transmit the external light rays transmitted/reflected in the light shielding sheet at an angleθwhich satisfies at leastθ<24+0.018×F, wherein,θis the angle of the external light ray made incident to the light shielding sheet and F is a focal distance (mm) of the Fresnel lens element. COPYRIGHT: (C)2005,JPO&NCIPI
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