| 摘要 |
A retroreflection sheet which is not only high in luminance to provide a bas ic optical characteristic generally desired for a triangular pyramid type reflection element, that is, excellent in reflection luminance represented b y the reflection luminance of light incident onto the front face of the triangular pyramid type reflection element, but is greatly improved in incident angle characteristics and rotational angle characteristics. A triangular pyramid type cube-corner retroreflection element characterized in that the optical axis of a triangular pyramid type reflection element is tilted in a direction of making plus (+) or minus (-) the difference (q-p) between a distance (q) from an intersection (Q) between the optical axis and the bottom base (Sx-Sx') up to the base (x, x, ...) shared by an element pai r and a distance (p) from an intersection (P) between a perpendicular line fro m the apex (H1, H2) of the element to the bottom base (Sx-Sx') and the bottom base (Sx-Sx') up to the base (x, x, ...) shared by the element pair so that an angle formed by the optical axis and the perpendicular line is 0.5 to 1.5 degrees.
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