Patent ID: 7190500
Filing Date: 2007-03-13
Classification: G01B,G02B,G02C

Abstract:
1. A deformable mirror having a displacement detecting function, comprising: a flexible thin film having a reflecting surface and an upper electrode to be deformed by electrostatic attraction; and a control electrode and a capacitance detecting electrode, located opposite to the flexible thin film, wherein a displacement of the reflecting surface can be calculated from a static capacitance between the upper electrode and the capacitance detecting electrode, and wherein a high-frequency voltage for detecting the static capacitance having a frequency much higher than a mechanical resonant frequency of the reflecting surface is superposed on a voltage of a constant-voltage source for deforming the reflecting surface, and a resistance is connected to a grounding side of the upper electrode to detect an amount of displacement of the reflecting surface from a phase and amplitude of an electric current flowing through the resistance.