Patent ID: 6177217
Filing Date: 2001-01-23
Classification: G02B,H04N,Y10S

Abstract:
A method for accurately positioning an array with periodic structures, for forming an image thereon, said method comprising the steps of:(i) producing a light beam along fast-scan axis;(ii) translating said array in a direction substantially perpendicular to said fast-scan axis;(iii) detecting said light beam alternatively by a pair of detectors, said detectors being located near opposite edges of said array along said fast-scan axis;(iv) providing substantially periodic signals by said pair of detectors in accordance with their detection of said light beam;(v) determining relative phases of said periodic signals, said relative phases corresponding to misalignment of said array;(vi) sensing phases of said periodic signals and rotating said array such that long axes of said periodic structures are substantially parallel to said fast-scan axis.