Patent ID: 8649097

Claim:
A method of controlling an inclination angle of a Fabry-Perot tunable filter, the Fabry-Perot tunable filter comprising: a first semitransparent mirror, which is fixed; a second semitransparent mirror, which is movable and arranged opposite the first semitransparent mirror; and three or more piezoelectric elements arranged at regular intervals on the second semitransparent mirror for changing a space between the first semitransparent mirror and the second semitransparent mirror, the method comprising a step of rotating the second semitransparent mirror around each of plural axes, as pivotal axes, wherein the plural axes lie in a plane parallel to the second semitransparent mirror, and each of the plural axes is equidistant, on the plane parallel to the second semitransparent mirror, from each of the three or more piezoelectric elements along a line normal between each of the plural axes and each of the three or more piezoelectric elements.