Patent ID: 7705983
Filing Date: 2010-04-27
Classification: G01J

Abstract:
1. A wavelength displacement correcting system for correcting a wavelength displacement of a spectral device, comprising: a diffraction grating for dispersing an incident beam; a light receiving section for receiving beams dispersed on the diffraction grating at each wavelength, and receiving diffracted beams of different orders; a light source for emitting the beam to be incident onto the diffraction grating, the light source including a light emitting diode to be driven by a constant current; a measuring section for measuring a forward voltage value of the light emitting diode to be obtained when the light emitting diode is driven by the constant current; and a computing section for computing a wavelength correction value based on output information from the light receiving section, and the forward voltage value of the light emitting diode, wherein the computing section is operative to, in response to incidence of the incident beam onto the diffraction grating by driving the light emitting diode of the light source, calculate a wavelength displacement amount of a monochromatic beam from the light emitting diode, based on the forward voltage value measured by the measuring section, and a forward voltage initial value, calculate displacement amounts of the diffracted beams, based on diffracted beam output values of different orders to be outputted from the light receiving section, and diffracted beam output initial values of different orders, and calculate a uniform wavelength displacement amount and a dispersion width displacement amount of the dispersed beams of the spectral device, based on the calculated wavelength displacement amount of the monochromatic beam, and the calculated wavelength displacement amounts of two diffracted beams of different orders.