| 摘要 |
PROBLEM TO BE SOLVED: To reduce the wavefront aberration of a reflection wavefront caused by the fact that the thin part of optical parts such as a deflection prism and a deflection mirror is pulled due to the expansion or contraction of adhesive in curing. SOLUTION: When the deflection optical parts is e.g. a deflection mirror 20 of a triangular prism composed of five planes, thick vertex angle parts 22, 23, 24 of two orthogonal planes are adhered/fixed in a dot-like manner on the pedestal parts 14, 15, 16 of a positioner 10 (holding member) by adhesive 25 being applied in a dot-like manner. The respective pedestal parts 14, 15, 16 are provided being stuck out of thick vertex angle parts 22, 23, 24 of the deflection mirror 20 i.e., out of the external form of the mirror outward. |
