Patent ID: 8711368
Filing Date: 2014-04-29
Classification: G01J,G02B

Abstract:
1. An optical filter comprising: a first substrate; a second substrate opposed to the first substrate; a first reflecting film provided to the first substrate; a second reflecting film provided to the second substrate, and opposed to the first reflecting film; a first electrode provided to the first substrate; a second electrode provided to the second substrate, and opposed to the first electrode; and a voltage controller that controls an electrical potential between the first electrode and the second electrode, wherein when switching a wavelength of a light beam to be dispersed by switching the electrical potential between the first electrode and the second electrode, and measuring an intensity of the light beam dispersed, the voltage controller switches the electrical potential from a first electrical potential to a second electrical potential larger than the first electrical potential, a time period during which the second electrical potential is set is longer than a time period during which the first electrical potential is set, the voltage controller sets the electrical potential between the first electrode and the second electrode to a third electrical potential larger than the second electrical potential, and switches the electrical potential from the second electrical potential to the third electrical potential, and an absolute value of a difference between the second electrical potential and the third electrical potential is smaller than an absolute value of a difference between the first electrical potential and the second electrical potential.