| 摘要 |
[Problem] To provide a reflecting mirror which makes it possible to reduce manufacturing costs of a reflecting mirror even when this is capable of suitably adjusting the relative position between said reflecting mirror and a lens barrel in a projection optical system in which the reflecting mirror is mounted. [Solution] This reflecting mirror 2 has a concave, curved reflecting surface. Defining the front surface as the surface on the formation side of the reflective surface and the back surface 2h as the surface opposite of the front surface, and defining the Z direction as the direction parallel to the optical axis L1 of the reflecting mirror 2 and the Z2 direction as the Z direction from the front surface towards the rear surface 2h, a level surface 2j orthogonal to the Z direction is formed on the back surface 2h of the reflecting mirror 2, as is a wall surface 2k that rises in the Z2 direction from at least part of the periphery of the level surface 2j. |
