Patent ID: 6219146
Filing Date: 2001-04-17
Classification: G01B

Abstract:
An apparatus for alignment of an optically reflective surface with a light beam, comprising:a beamsplitter disposed in said light beam, said beamsplitter spaced-apart from said optically reflective surface, said beamsplitter configured to divide said light beam into a first beam portion propagating in a first direction and a second beam portion propagating in a second direction differing from said first direction, said first beam portion being reflected from said optically reflective surface onto said beamsplitter;a retro-reflector disposed in said second beam portion, said retro-reflector reflecting said second beam portion onto said beamsplitter in a direction counterparallel to said second direction; anda telescope disposed to collect said first beam portion and said second beam portion after reflection respectively at said optically reflective surface and said retro-reflector, and image said first and second beam portions onto a target plane as two point images.