Abstract

Several design forms are shown that seem to give the minimum volume, for 3, 5, and 7 elements, to the 1994 IODC design problem, with a volume of 23,000 cubic mm for the best one. If the design constraints are ignored, the ultimate limit found, so far, has just three elements, has diffractive aspheric surfaces and has a volume of about 2500 cubic mm. The right mix of purely refractive power and purely diffractive power is the key to this 70 degree field f/.9 design with no vignetting.

© 1994 Optical Society of America