| 摘要 |
PROBLEM TO BE SOLVED: To enable stable mounting in such a manner that a deviation does not arise in a reflection angle by a temp. change by determining material quality and size in such a manner that the angle change of a mirror attains the value smaller than a permissible value with respect to a permitted temp. change. SOLUTION: The size of a bracket 28 from the axial center of a screw 26 measured along the mounting surface 18A of an optical box 18 to the front end of an adjusting screw 24 is defined as L1, the size of the optical box 18 from the axial center of the screw 26 to the front end of a projection 22 as L2 and the size from the front end of the adjusting screw 24 to the front end of the projection 22 as Lh. The sizes of L1, L2 and Lh are so determined as to satisfyθ>=|tan<-1> [ L1(1+α1×ΔT deg.C)-L2(1+α2×ΔT deg.C)}/Lh]|when the angle error of the mirror permissible for the device is within±θand the permissible temp. change isΔT deg.C. In the equation,α1 denotes the coefft. of linear expansion of the projection 22 andα2 denotes the coefft. of linear expansion of the bracket 28. |
