04241389 is referenced by 14 patents and cites 8 patents.

A multiple apparent source optical imaging system is provided having a paraboloidal assembly of plane mirrors uniformly distributed in a ring about an anisotropic light source. The assembly compensates for source anisotropy and for diffraction effects by providing uniform distribution of light, as if the light originated from multiple apparent sources uniformly distributed in a selected annular fashion in a common apparent source plane. The assembly also includes a variable focus projection lens which, in conjunction with a selected source beam divergence angle, serves to minimize line-width error when objects, such as a mask and a semiconductor substrate, with a finite separation are illuminated. Substantially no loss in image intensity is occasioned by the system.

Title
Multiple apparent source optical imaging system
Application Number
798113
Publication Number
4241389
Application Date
April 25, 1979
Publication Date
December 23, 1980
Inventor
Richard J Heimer
Encino
CA, US
Agent
Roland I Griffin
Assignee
Kasper Instruments
CA, US
IPC
F21V 7/09
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