| 摘要 |
PURPOSE:To make the device compact and light weight, by sharing a laser collimator, a polarization converting means, and a beam splitting polarizer, as a light receiving optical system which introduces the reflected light from a target into a light detector. CONSTITUTION:The reflected light of laser light is inputted into the light detector 18 through an objective lens 22 as the laser collimator, a dichroic mirror 20, a concave lens 24, rectangular prisms 23 and 21, the beam splitting polarizer 13, and a converging lens 17. The laser light outputted from the beam splitting polarizer 13 to the rectangular prism 21 is totally reflected four times until it is inputted to the beam splitting polarizer 13 again. Therefore it is linearly polarized again. However, since its plane of polarization forms a right angle with the plane of polarization of the beam splitting polarizer 13, the reflected light can be introduced into the optical detector 18 with almost no polarizing loss. |
