| 摘要 |
PROBLEM TO BE SOLVED: To provide a beam light projecting/receiving apparatus in which the beam diameter is easily made small at a light projecting/receiving separation part and in the vicinity of a scan mirror. SOLUTION: The beam light projecting/receiving apparatus includes: a light source 3 wherein a light emission part has a major axis direction and a minor axis direction; a beam light projection optical system; a scan mirror 11; a projecting/receiving light separation member 13 which separates a projected luminous flux and a returned luminous flux; a light receiving element 5; a condenser lens part 15 which condenses the returned luminous flux onto the light receiving element 5. The beam light projection optical system is constituted by arranging: a collimator lens part 51 having a positive refractive power with respect to both the major axis direction and the minor axis direction of the light emission part; a focusing lens part 52 which is disposed nearer side to an object side than the back side focal point of the collimator lens part 51, has a positive refractive power both in the major axis direction and the minor axis direction, and forms the image of the light emission part on the object side; and a projection lens part 53 which has a positive or a negative refractive power in the minor axis direction, brings the luminous flux in the minor axis direction into a near-parallel luminous flux and has the absolute value of the refractive power in the major axis direction smaller than the absolute value of the refractive power in the minor axis direction. COPYRIGHT: (C)2010,JPO&INPIT
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