| 摘要 |
PROBLEM TO BE SOLVED: To provide a reflection screen for improving uniformity and contrast of brightness. SOLUTION: The reflection screen 1 has a screen face 11 for reflecting projection light emitted from a projection light source. A screen face 11 includes a circular fresnel lens part 12 whose cross section is in the form of a saw blade. The center of a concentric circle of the circular fresnel lens part 12 is positioned on the outside of the screen face 11. In addition, the circular fresnel lens part 12 is composed as an assemblage of unit prisms having a first oblique face being a tilt face of the side of the center of the concentric circle and a second oblique face being a tilt face of the opposite side to the first oblique face. The first oblique face is light reflection face and the second oblique face is a non-reflection face. COPYRIGHT: (C)2009,JPO&INPIT
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