| 摘要 |
PROBLEM TO BE SOLVED: To provide a linear lighting system efficiently illuminating a copy, obtaining sufficient illuminance on the copy without low electric power consumption, and providing uniform illuminance distribution. SOLUTION: The following imaging formula is obtained in order to perfectly imaging luminous flux emitted through a luminous flux emitting surface on the surface of a copy in the case where a diffusion reflecting part 54 is used as a secondary light source. n(y2+(l0-z)2)1/2+(y2+(l1+z)2)1/2=nl0+l1. Here, a coordinate system is set such that the surface top of the luminous flux emitting surface in a sectional parallel to longitudinal end surfaces of the light guiding body 50 is set as the origin 0 of coordinates, the optical axis is set as the z-axis, and the axis orthogonal to the optical axis is set as the y-axis, then l0 is the length on the z-axis from the surface top 0 to the diffusion reflecting part 54, l1 is the length on the x-axis from the surface top 0 to the surface of the copy, and n is a reflective index of the light guiding body 50 to air. Then, the shape of the luminous flux emitting surface is designed by the imaging formula above and the following general formula representing a shape of an aspheric (non-cylindrical) surface of a lens, z=cy2/(1+(1-(1+k)c2 y2)1/2). |
