Patent ID: 7116417

Claim:
A spectrometer capable of correcting a displacement of a dispersed light image, comprising: a light source which outputs a monochromatic ray of light; a slit member formed with at least one incident slit through which the monochromatic ray from the light source is passed; an optical system which images a dispersed light image of the monochromatic ray through the incident slit on an imaging plane; a sensor array including a number of photoelectric conversion elements arrayed on the imaging plane where the dispersed light image is imaged by the optical system, the number of photoelectric conversion elements receiving dispersed light according to wavelengths so as to output an electrical signal in correspondence to an intensity of the received light with respect to each wavelength component; and a calculator which calculates a variation in an imaging position of a primary dispersed light image of the monochromatic ray through the incident slit on the imaging plane from an initial position thereof as a first image displacement amount, and calculates a variation in an imaging position of a secondary dispersed light image of the monochromatic ray through the incident slit from an initial position thereof as a second image displacement amount, and calculates, based on the first and second image displacement amounts, a third image displacement amount which is free of an influence due to a fluctuation of a wavelength of the monochromatic ray.