Patent ID: 7333198

Claim:
A system for use in alignment of both tilt and vertical positioning of samples comprising: a) a source (LS) of electromagnetic radiation; b) a beam splitter (BS); c) at least a first (M 1 ) mirror; d) first (QD 1 ) and second (QD 2 ) alignment detectors; e) at least focusing (L 1 ) and collimating (L 2 ) lenses; f) a stage for supporting a sample (S); and g) a chopper (CHP); said source (LS) of electromagnetic radiation being positioned to direct a beam of electromagnetic radiation toward said beam splitter (BS); said beam splitter (BS) being positioned to direct a first portion of said beam toward said first mirror (M 1 ), which reflects said first portion of said beam through said focusing lens (L 1 ) and obliquely onto said sample (S) such that it impinges at substantially to same location at which the second portion of said beam, which is directed normally toward said sample (S) by said beam splitter (BS), impinges; said second portion of said beam being reflected from said sample (S) substantially directly back along the path of its incidence, through said beam splitter (BS) and into said second alignment detector (QD 2 ); said first portion of said beam being reflected from said sample (S), through said collimating lens (L 2 ) and into said first alignment detector (QD 1 ); and said chopper (CHP) being positioned between said light source (LS) and said beam splitter (BS) such that said beam of electromagnetic radiation directed toward said beam splitter (BS) passes therethrough and in use serves to sequentially change the intensity of said electromagnetic beam.