| 摘要 |
PURPOSE:To prevent an appearance of stray light without enlarging optical elements in shape by providing an aperture of a specific shape with an elliptical opening between a collimator lens and a beam shaping means. CONSTITUTION:The aperture 7 is provided having an approximately elliptical opening with its minor axis (p) and major axis (q) in the same direction with those minor and major axes of a parallel beam cross section under the condition of q/p b/a and p<c and is positioned between the collimator lens 2 from which a parallel beam having an approximately elliptical cross section with a minor axis (a) and major axis (b) is outgoing and the beam shaping means having an incident effective opening diameter on minor axis side (c) which magnifies the minor axis of said parallel beam by b/a approximately. Thus, even if a radiation angle on the side of parallel to the coupling direction of a semiconduc tor laser chip is larger than the standard, an incident beam into the optical elements is limited by the aperture so that genetic stray light can be prevented. |
