| 摘要 |
PURPOSE:To facilitate the relative positional adjustment between a source of light and a collimator lens by composing the collimator lens of two lenses having different focal distances and moving a long focal lens along an optical axis. CONSTITUTION:The collimator lens is composed of two lenses 20 and 21, where the lens 20 is the long focal lens as longer than the lens 21 in focal distance and freely movable in the direction of the optical axis by means of an actuator 200. Consequently, a relative positional change, etc., between the source of light 10 and the lens 19 due to temperature is detected by a temperature sensor 210 and an arithmetic circuit 211, etc., so that the lens 20 is controlled in its movement in the direction of the optical axis, thus facilitating the relative positional adjustment between the source of light and the collimator lens. |
