| 摘要 |
PROBLEM TO BE SOLVED: To provide a cylindrical lens for a line laser unit, by which the brightness of a laser beam is equalized at the center part and the peripheral part and the visibility becomes excellent even if the output of a laser source is not increased. SOLUTION: The laser beam is projected from a laser source 21 toward a collimator lens 22. The laser beam is extended in only one direction by means of the cylindrical lens 23 to irradiate an object to be irradiated. At least a half part of the circumference of the cylindrical lens 23 is a coated surface 24. The coated surface 24 transmits the laser beam. The light transmittance in the vicinity of the coating surface 24 in the periphery is higher than that of anyplace else. The collimator lens 22 is arranged between the laser source 21 and the cylindrical lens 23 such that the parallel laser beam transmitted through the collimator lens 22 is extended in only one direction by means of the cylindrical lens 23. COPYRIGHT: (C)2004,JPO
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