| 摘要 |
PURPOSE:To control the relative deviation between a light source and a lens in a direction perpendicular to the lens optical axis and to obtain stability with respect to temperature by providing a lens holder or light source holder with a mechanism which absorbs elastically heat stress due to the difference in coefficient of thermal expansion between both holders. CONSTITUTION:A light source holding part 3 where a semiconductor 1 is fixed to a coupling member 4 by shrinkage fitting, and the coupling member 4 is clamped threadably to the lens holder 5. The focal length of a coupling lens 2 varies with temperature, so the coupling member 4 and lens holder 5 are made of metals having different coefficients of thermal expansion in such a temperature compensating structure that the light emission point of the semiconductor laser 1 is fixed at the focal length position of the coupling lens 2 according to variation in the focal length. The engagement part between the light source holding part 3 and coupling member 4 is cylindrical, so isotropy is obtained against temperature variation. Consequently, motion in the same surface of the semiconductor laser 1 is only motion depending upon the unbalance of the cylindrical engagement part and suppressed small, thereby obtaining stability as to temperature. |
