| 摘要 |
<P>PROBLEM TO BE SOLVED: To preferably retard thermal deformation of a mirror used in an optical system. <P>SOLUTION: In the mirror base of a planar mirror 1 provided with a reflection film 11 having a light reflection surface, and a mirror base 12 supporting the reflection film, a flow path FP is provided. The flow path FP includes a first flow path P1 which opens to at least one place on the outer surface of the mirror base and at least one place on the back side of the reflection film in the mirror base, a plurality of second flow paths P2 located at least partially on the back side of the reflection film and extending radially from the first flow path side to the side end of the mirror base, a buffer tank PB connected to the plurality of second flow paths, respectively, and a third flow path P3 having one end connected to the buffer tank and the other end opening to the outer surface of the mirror base. <P>COPYRIGHT: (C)2012,JPO&INPIT |
