Variable geometry mirror having high-precision, high geometry controllability

摘要

A flexible thin film is supported by a frame member through two end portions opposing each other. A reflection surface is provided on the flexible thin film to reflect light. A first electrode is provided integrally with the flexible thin film. A second electrode is substantially fixed to the frame member so as to oppose the first electrode on an opposite side of the reflection surface. A third electrode is substantially fixed to the frame member so as to oppose the first electrode on the same side as the reflection surface. An optical opening for introducing light into the reflection surface is provided on the side of the reflection surface. At least one of the second and third electrodes is divided in the direction connecting the two end portions. The configuration of the reflection surface is controlled to a desired configuration by applying a desired voltage selectively to between the first electrode and the divided second or third electrode.