| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light transmissive sheet which can suppress a secondary transmitted light component T2, shows highest luminance in a front direction, has broad light distribution characteristic in a direction within a prescribed visual field angle and further has strong directivity in the front direction. <P>SOLUTION: In the light transmissive sheet, there is a finite focal distance at an incident side of illumination light and a lot of toroidal lens bodies having a crosssection of a bisymmetrical shape and infinite radius of curvature in a generatrix direction of a paraboloid are continuously arranged. When a Z-axis is taken in parallel to a normal line of a transparent sheet, a Y-axis is taken in parallel to a generatrix of the paraboloid and a X-axis is taken in a row direction of the toroidal lens bodies, a XZ cross sectional shape of the light transmissive sheet is expressed by Z=-X<SP>2</SP>/80 which is obtained by substituting 40 for R in Z=-X<SP>2</SP>/2R. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
