Wavelength variable interference filter, optical module, and light analyzer

Abstract

A wavelength variable interference filter includes: a first movable mirror disposed on a first substrate; a second movable mirror disposed so as to be opposed to the first movable mirror with a predetermined gap interposed therebetween; and an electrostatic actuator which varies the length of the gap between the mirrors. The first substrate has a first movable portion on which the first movable mirror is disposed, and a first linkage portion which holds the first movable portion in such a manner that the first movable portion can shift in the thickness direction of the substrate. The second substrate has a second movable portion on which the second movable mirror is disposed, and a second linkage portion which holds the second movable portion in such a manner that the second movable portion can shift in the thickness direction of the substrate.

What is claimed is: 
     
         1 . A wavelength variable interference filter, comprising:
 a first substrate;   a second substrate that is disposed so as to be opposed to the first substrate;   a first mirror that is disposed between the first substrate and the second substrate;   a second mirror that is disposed between the first mirror and the second substrate;   a first electrode that is disposed between the first substrate and the second substrate; and   a second electrode that is disposed between the first electrode and the second substrate,   the first mirror being displaced toward a second mirror side by applying a voltage between the first electrode and the second electrode,   the second mirror being displaced toward a first mirror side by applying the voltage between the first electrode and the second electrode.   
     
     
         2 . The wavelength variable interference filter according to  claim 1 ,
 the first substrate having a first portion and a second portion,   looking from a first substrate side to the second substrate side, the first mirror overlapping to the first portion.   
     
     
         3 . The wavelength variable interference filter according to  claim 2 ,
 the first portion being thicker than the second portion.   
     
     
         4 . The wavelength variable interference filter according to  claim 2 ,
 looking from the first substrate side to the second substrate side, the second mirror overlapping to the first portion.   
     
     
         5 . The wavelength variable interference filter according to  claim 2 ,
 looking from the first substrate side to the second substrate side, the first electrode overlapping to the second portion.   
     
     
         6 . The wavelength variable interference filter according to  claim 2 ,
 the second substrate having a third portion and a fourth portion,   looking from the first substrate side to the second substrate side, the second mirror overlapping to the third portion.   
     
     
         7 . The wavelength variable interference filter according to  claim 6 ,
 the third portion being thicker than the fourth portion.   
     
     
         8 . A wavelength variable interference filter comprising:
 a first mirror;   a second mirror that is disposed so as to be opposed to the first mirror; and   a gap varying unit that displaces the first mirror to a second mirror side and the second mirror to a first mirror side.   
     
     
         9 . An optical module comprising:
 the wavelength variable filter according to  claim 1 .   
     
     
         10 . A light analyzer comprising:
 the wavelength variable filter according to  claim 1 .