Filter module with disk shaped tunable optical filter

摘要

A disk shaped optical filter module, comprising:
a disk shaped optical filter having such a filter characteristic that a transmission central wavelength varies along a circumferential direction with respect to a viewing angle;a scanning mechanism for scanning a wide range of transmission central wavelengths by rotating the disk shaped optical filter while setting optical beams incident onto the disk shaped optical filter; anda correction mechanism for controlling a transmission position of the optical beams of the scanning mechanism in a tangential direction so as to correct a deviation of the transmission central wavelength scanned by the scanning mechanism.