Patent ID: 6075597
Filing Date: 2000-06-13
Classification: G01J,G02B

Abstract:
A optical system comprising:a means capable of forming an image, said means having an entrance pupil through which a beam of light enters said optical system, said means further having two mirrors, the first of said mirrors intercepting said beam of light and causing it to converge, the first of said mirrors further having a perforation, the second of said mirrors directing said converging beam of light from said first mirror toward said perforation in said first mirror, said converging beam of light passing through said perforation and emerging on the side of said first mirror farthest from said second mirror, said emerging, converging beam of light having an axis, anda filter characterized by a dependence on the angle of incidence of said axis of said emerging, converging beam of light upon said filter of the wavelengths of light transmitted by said filter from among the constituent wavelengths of said emerging, converging beam of light anda converging lens, said optical system being so arranged that said emerging, converging beam of light is incident upon said filter before said light transmitted by said filter passes through said converging lens, said converging lens forming a real image by directing said light transmitted by said filter to a focus, andsaid means capable of forming an image forming, however, no real image before said light transmitted by said filter passes through said converging lens.