| 摘要 |
<p>A light source device comprising a light guide (3) for guiding a primary light-source light and slantingly outputting it from an output surface (33), and a light deflection element (4) disposed adjacent to the light output surface, a plurality of parallel prism rows being formed on the light incident surface (41) of the light deflection element. A prism plane on a distal side of the primary light source has a convexly-curved surface shape with respect to a virtual prism row configuration, when assuming a virtual prism row (I) which receives at one prism plane a peak output light in an output light distribution from the light guide's output surface, totally reflects it internally off the other prism plane, and outputs the reflected light via an output surface (42) in a desired direction, and which is arranged at the same pitch as the prism row arranging pitch of the light deflection element with a vertical angle of 50-70°. A value (r/P) of radius r of curvature standardized by the arranging pitch P of a prism row is 7-30, and a ratio (d/P) between a maximum distance d from a prism plane to the prism plane of the virtual prism row (I) and the arranging pitch P of a prism row is 0.05-5%.</p> |
