Patent attributes
In a reflecting-mirror supporting mechanism, elastic rotation about the lateral X axis is made possible by providing first spring elements 2 and second spring elements 3 in a bipod 1. In addition, elastic rotation about the lateral Y axis is made possible by a spring member 6, and elastically translational displacement along the axial Z axis is made possible by a parallel-spring member 9. The two legs of the bipod 1 are arranged with their upper ends getting close to each other with a predetermined distance at a tilt with respect to the axial Z axis. Variations in moment load generated in the reflecting mirror can be suppressed by making the intersecting point of the center axes of the two legs of the bipod 1 agree with the position of the center of gravity of the reflecting mirror.