Patent ID: 6621577
Filing Date: 2003-09-16
Classification: G02B

Abstract:
A spectral rejection device for forming an image on an optical sensor, having a given spectral width, comprising:(a) means for forming a first beam of parallel light rays coming from an observed scene; (b) dispersing means for spectrally dispersing said beam in at least one first direction along which the wavelength of the dispersed light rays vary substantially continuously; (c) at least one mask arranged in the path of the dispersed rays to intercept at least one band of wavelengths thereof; (d) displacing means for displacing said mask generally in said first direction at a high speed over a distance corresponding generally with said spectral width of the optical sensor; (e) combining means for combining the dispersed rays into a second beam of parallel rays; and (f) focusing means for focusing said second beam onto the sensor, said mask being so dimensioned as to intercept a narrow band of wavelengths without modifying the sensitivity of the operating point of the sensor and without significantly modifying the transmission of the mask when it is displaced in said first direction.