Brief description of embodiments of a device for correcting optical system application and relates to such a device

摘要

1489804 Lighting fittings ENVIRONMENTAL RESEARCH & TECHNOLOGY Inc 21 March 1975 [5 April 1974 (2)] 11969/75 Heading F4R An optical system including an optical device, such as an interference band-pass filter, having a transmission characteristic which is dependent on the angle of incidence of input radiation comprises an optical equalizer designed to produce a substantially uniform light intensity across its output aperture irrespective of intensity variations across its input aperture, and means for collimating the light emitted by the equalizer and directing it to the device. The equalizer may be of the type disclosed in Specifications 1,489,805 or 1,489,806 or alternatively may consist of powdered material suspended in a light transmissive liquid.