| 摘要 |
PROBLEM TO BE SOLVED: To suppress deformation due to a thermal effect of an aperture.SOLUTION: A cylindrical lens fixing member 301 includes an installed portion 309 and an aperture 104. A fixing member installing surface 302 is separated from the aperture 104, and the aperture 104 is provided on an optical housing 108 in a non-contacting state. Therefore, as compared with one in which the aperture 104 is a separated body and directly installed to the optical housing 108, the heating value of heat transmitted to the installed portion 309 is gradually decreased till reaching the aperture 104. The aperture 104 is provided on the optical housing 108 in the non-contacting state, so that the heating value of thermal transmission to the aperture 104 is small as compared with the heating value from the optical housing 108 when contacted with the optical housing 108. |
