| 摘要 |
PURPOSE:To obtain a simple structure where the position of an image surface can be corrected when the ambient temperature is changed, by inclining the second mirror at the same angle as the first mirror in accordance with a minute angular variation of the first mirror to obtain a parallel luminous flux and moving the second mirror in parallel. CONSTITUTION:Mirrors 3 and 3, materials 12 which are expanded/contracted by temperature, materials 11 which are hardly expanded/contracted by temperature, and a structure consisting of a rotatable node are provided between an optical system 1 and an image surface 14. The expansible material 12 is fixed by an immobile point 13 of a barrel and a point on the back of one mirror 3, and the mirror 3 whose reflected face is directed to the optical system 1 is rotated on a rotation node 7 on an optical axis 2, and another mirror 4 is placed to face the first mirror 3 in parallel and is fixed by a rotation node 10, and body ends of the unexpensible material 11 are fixed by two mirrors 3 and 4. |
