| 摘要 |
PURPOSE: To correct the astigmatism of a radial beam by providing the device with two focusing elements where two orthogonal surfaces have different focusing force relatively rotatable around a radial beam axis. CONSTITUTION: The two focusing elements 5 and 6 where the two orthogonal surfaces have the different focusing force are made, for instance, to be weak columnar lenses, and are arranged relatively rotatably around the radial beam axis 13 of a semiconductor laser 1. When the imaginary focus of the semiconductor laser 1 is a point 12 and is away by a distanceΔZ from the focal surface 18 of a compound lens 3, the imaginary focus of an output beam is not on the focal surface of the compound lens 3, so that a beam 4 from a synthetic lens 3 is deviated by an angleθwithout being accurately collimated. The angleΔθis corrected in two stages by the columnar lenses 5 and 6. The deviated angleθof the beam 4 is reduced half by the lens 5, and is reduced to substantially come to zero by the lens 6.
|
