Patent ID: 7167292

Claim:
A spectroscope that resolves a light beam into separated light beams having various wavelengths, and selects and extracts a separated light beam having an arbitrary wavelength from among these separated light beams, comprising: a first mask disposed such that a transmission area of each of the separated light beams in a spectrum direction is limited; and a second mask disposed such that the transmission area of each of the separated light beams in a direction perpendicular to said spectrum direction is limited, where said spectrum direction denotes a direction of the arrangement of these separated light beams when viewed against the line of the resolved separated light beams, wherein: said first mask includes a pair of first mask members which are independently movable closer to or further away from each other so as to adjust a first length of said transmission area in said spectrum direction and a first position of said transmission area in said spectrum direction; and said second mask includes a pair of second mask members which are independently movable closer to or further away from each other so as to adjust a second length of said transmission area in said direction perpendicular to said spectrum direction and a second position of said transmission area in said direction perpendicular to said spectrum direction.