Patent ID: 6473243
Filing Date: 2002-10-29
Classification: G02B,G03F

Abstract:
A catadioptric imaging system for forming a reduced image of a first plane onto a second plane, comprising:a first imaging optical system having a dioptric imaging optical system; a second imaging optical system having a catadioptric imaging optical system; wherein said first imaging optical system comprises in the order from the first plane, a first lens group having a positive refracting power, an aperture stop, and a second lens group having a positive refracting power, for forming a primary image of the first plane; said second imaging optical system comprises a primary mirror having a first reflecting surface and a first radiation transmitting portion at the center thereof, a secondary mirror having a second reflecting surface with a second radiation transmitting portion at the center thereof, and a refracting member separated from said first reflecting surface and said second reflecting surface, for forming a secondary reduced image of the first plane on the basis of the radiation from said primary image, said first reflecting surface having a front surface reflecting surface in a concave form; and the radiation from said primary image passes through said first radiation transmitting portion of said primary mirror and said refracting member to be reflected by said secondary mirror, the radiation reflected by said secondary mirror passes through said refracting member to be reflected by said primary mirror, and the radiation reflected by said primary mirror passes through said refracting member and said second radiation transmitting portion of said secondary mirror to form said secondary image.