| 摘要 |
PROBLEM TO BE SOLVED: To provide technique which is suitable for shortening the depth of a video display device, without significantly impairing the image quality (brightness) of a display video on a screen. SOLUTION: A total reflection type prism part (10), emitting an incident light beam as an emitted light beam having a specified emitting angle by a total reflection phenomenon after a 1st refraction phenomenon, is provided in a range where the incident angle of a projected video projected from an optical component on the Fresnel lens sheet (6), constituting the rear projection screen, is at least≥about 40°on the video generating source side of the Fresnel lens sheet (6), and a refraction type prism part (11), emitting the incident light beam as the emitted light beam having a specified emitting angle by a 2nd refraction phenomenon, is provided in a range facing a part where the total reflection type prism part is not provided on the video observation side of the Fresnel lens sheet. COPYRIGHT: (C)2005,JPO&NCIPI
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