| 摘要 |
PURPOSE:To prevent the flexural vibration of a reflecting mirror without mak ing assembling operation complicate nor fouling nor damaging a reflecting surface by fixing the reflecting mirror so that the mirror is curved in its plate thickness direction. CONSTITUTION:At least three projections A-C for positioning are arranged on an optical housing 13 where the reflecting mirror 11 is fixed and positioned, and the reflecting mirror support surfaces A1, B1, and (C1) of the respective projections A-C are set nonlinear. Namely, the support surfaces A1 and (C1) of the projections A and C at both the ends stand in a straight line, but only the support surface B1 of the center projection B is shifted in position forward. Consequently, the reflecting mirror 11 while forcibly deflected is pressed contacting and both the end parts of the front surface side of the reflecting mirror 11 are elastically pressed contacting and fixed with a leaf spring 12, etc., so as to fix the reflecting mirror 11 on the support surfaces A1, B1, and (C1) of the projections A-C. This deflection prevents the flexural vibration of the reflecting mirror 11 due to external vibration. |
