Wavelength tunable interference filter, optical filter device, optical module, and electronic apparatus

A wavelength tunable interference filter, comprising:

• a first substrate;
• a second substrate disposed so as to face the first substrate;
• a first reflective film that is provided on the first substrate;
• a second reflective film that is provided on the second substrate, is disposed so as to face the first reflective film;
• and
• a gap change portion that changes a size of a gap between the first and second reflective films by bending the second substrate to a side of the first substrate,
• wherein, in an initial state where the size of the gap is not changed by the gap change portion, the second substrate is curved so as to be convex on an opposite side to a side where the first substrate is disposed, and
• a first reflectance of each of the first and second reflective films at a first wavelength in a visible wavelength range is lower than a second reflectance of each of the first and second reflective films at a second wavelength longer than the first wavelength in the visible wavelength range;
• and
• a curve forming portion is provided on the second substrate and curves the second substrate to the opposite side to the side where the first substrate is disposed.