| 摘要 |
PURPOSE:To obtain a reflection mirror whose resolution is stable and in which the setting of an optical axis and a mirror axis is not changed even when the posture of the reflection mirror is changed in a gravity direction mainly as for the large-sized reflection mirror. CONSTITUTION:An attaching plate 34 having lower rigidity than a mirror cell 2 is installed in an attaching part for attaching a positioning mechanism 30 to the mirror cell 2 as for a part of or all of plural positioning mechanisms. A positioning body 31 is attached between the attaching plate and the reflection mirror 1, and attaching part load lever 40 which allows tensile force or pressing force to act on the attaching plate 34 from the back side of the mirror cell 2, whereby displacement difference between the respective attaching parts is eliminated even when the posture of the reflection mirror 1 is changed. |
