| 摘要 |
PROBLEM TO BE SOLVED: To provide such a shape of a light guide and such a form of a linear light source device that the light guide can be reduced in length without reducing an effective irradiation width and a luminous intensity distribution of light emitted from the light guide can be adjusted.SOLUTION: A light source device for use in a document reader which reads document reflected light from a document includes a bar-shaped light guide 21 made of a light-transmissive member and an LED light source 22 arranged in at least one end part of the light guide, and a main reflection part 23 formed to extend in a lengthwise direction and a light emission surface 24 arranged to face the main reflection part are provided on side surfaces of the light guide. Light reflected by the main reflection part is emitted to the document side via the light emission surface. In at least one end part of the light guide, an incidence surface 26 receiving light from the LED light source and a sloping surface 27 inclined with respect to the incidence surface are provided. The sloping surface is adjacent to the incidence surface, and an auxiliary reflection part 28 reflecting the light from the LED light source is formed on the sloping surface, and the auxiliary reflection part is configured to reflect light impinging on the sloping surface, to the document side. |
