| 摘要 |
In order to suppress fluctuations in the amount of light reflected from an illumination surface having directional reflection characteristics and improve the usage efficiency of light flux irradiated from a light source, this illumination device illuminates an surface to be illuminated and comprises: a planar light source arranged above the normal line of the surface to be illuminated; and a reflection structure provided between the planar light source and the surface to be illuminated so as to surround the normal line, and reflecting light irradiated from the planar light source towards the surface to be illuminated. At least three reflective areas that reflect light towards the surface to be illuminated and at least three non-reflective areas that do not reflect light towards the surface to be illuminated are arranged in the reflection structure by alternately arranging the reflective areas and the non-reflective areas along a virtual cylindrical surface surrounding the normal line, in the circumferential direction of said virtual cylindrical surface. Each of the at least three reflective areas are partially cylindrically shaped areas that follow the virtual cylindrical surface. The at least three non-reflective areas are arranged scattered in the circumferential direction, so as to surround the normal line. |
