Patent ID: 8786861
Filing Date: 2014-07-22
Classification: G01J,G02B

Abstract:
1. An optical device comprising: a variable wavelength interference filter that include an effective measurement area and that transmits a first light reinforced by multiple interference out of an incident light; a telecentric optical system that guides the incident light to the variable wavelength interference filter; and a detection section that detects a second light transmitted through the variable wavelength interference filter, wherein the variable wavelength interference filter includes the telecentric optical system guides a principal ray of the incident light perpendicularly to one of a plane of the first reflecting film and a plane of the second reflecting film, and collects the incident light in the effective measurement area of the variable wavelength interference filter, a center, which has the center gap when the movable section is displaced with a maximum amount by the gap varying section, of the effective measurement area is in a central axis of the movable section, and a periphery, which has the peripheral gap when the movable section is displaced with the maximum amount by the gap varying section, of the effective measurement area is in a peripheral area of the first and second reflecting films, and a gap difference between the center gap and the peripheral gap is within a predetermined nanometric range.