Patent Number: 6,169,634

Title: Illumination techniques for overcoming speckle artifacts in metrology applications

Abstract: A method and apparatus for converting a beam of light that is substantially coherent and has a coherence length into substantially incoherent radiation. The method has the steps of collimating the beam, delaying a first portion of the beam by a first optical delay by ballistic passage through a first cell of an optical element, and delaying each of a plurality of other portions of the beam by an optical delay different from the first optical delay by an amount exceeding the coherence length of the beam.

Inventors: Sirat; Gabriel Y. (Jerusalem, IL)

Assignee: Optimet, Optical Metrology Ltd

International Classification: G02B 27/48 (20060101); G02B 027/30 ()

Expiration Date: 01/02/2018