Patent ID: 8294990
Filing Date: 2012-10-23
Classification: G01J,G02B

Abstract:
1. An apparatus comprising an optical filter having first and second pass bands that are different, said optical filter including: selectively operable first pass band adjusting structure that varies a characteristic of said first pass band without influencing said second pass band; and first and second edge filter elements that are fixedly coupled and supported for simultaneous tilting movement relative to a first path of travel for radiation, said first pass band adjusting structure effecting tilting movement of said edge filter elements relative to said first path of travel, one of said edge filter elements passing and reflecting radiation respectively above and below a first wavelength that is the shortest wavelength within said first pass band, and the other of said edge filter elements reflecting and passing radiation respectively above and below a second wavelength that is the longest wavelength within said first pass band, said first and second wavelengths respectively increasing and decreasing as said edge filter elements are tilted in a first direction, and respectively decreasing and increasing as said edge filter elements are tilted in a second direction opposite said first direction, said edge filter elements being positioned so that radiation within said first pass band that arrives along said first path of travel is reflected successively by said first and second edge filter elements and then departs said second edge filter element along a second path of travel.