| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a linear light source capable of projecting linearly polarized light at high efficiency, a planar lighting device using the same, and an image display. <P>SOLUTION: The linear light source comprises a point light source; an incident surface where the light from the point light source enters; an exit surface which crosses with the incident surface and projects the incident light; a surface which faces the exit surface; a linear lightguide which crosses with the incident surface, and comprises first and second side surfaces positioned between the incident surface and the opposite surface; a reflection film which is so arranged as to cover at least any one of the opposite surface of the linear light guide, the first side surface, and the second side surface; and a reflecting polarizer which is so arranged as to counter the exit surface of the linear lightguide. An XYZ coordinate system is assumed where the advancing direction of the main beam of the incident light is taken as Z-axis direction, an X-axis direction is such that the exit surface falls into a ZX surface, and the direction orthogonal to the X-axis direction and Z-axis direction is taken as a Y-axis direction. Here, the linear lightguide comprises a plurality of reflecting surfaces which reflect a part of the incident light toward the exit surface side, and each of a plurality of first reflection surfaces forms in a counterclockwise direction an elevation angle α1 (0<α1<90°) by an intercept against the ZX surface relative to the X-axis. <P>COPYRIGHT: (C)2004,JPO |
