OPTICAL FILTER, OPTICAL FILTER MODULE, SPECTROMETER AND OPTICAL APPARATUS

摘要

PROBLEM TO BE SOLVED: To restrain the movable range of a wavelength variable filter.SOLUTION: An optical filter 300 comprises a first wavelength variable bandpass filter BPF (1), a second wavelength variable bandpass filter BPF (2), a drive part 301 and a control part 303 for variably controlling a spectral band of each bandpass filter. The first wavelength variable bandpass filter can spectrally diffract a first wavelength band (400 nm to 460 nm) in a desired wavelength band and has at least a first spectral band b1 having the center wavelength of a first wavelength in the first wavelength band and a second spectral band b2 having the center wavelength of a second wavelength in the first wavelength band as a spectral band. The second wavelength variable bandpass filter can spectrally diffract a second wavelength band (480 nm to 540 nm) adjacent to the first wavelength band in a desired wavelength band and has at least a third spectral band b5 having the center wavelength of a third wavelength in the second wavelength band and a fourth spectral band b6 having the center wavelength of a fourth wavelength in the second wavelength band as a spectral band.