The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 23, 1980
Filed:
Apr. 25, 1979
Richard J Heimer, Encino, CA (US);
Kasper Instruments, Inc., Sunnyvale, CA (US);
Abstract
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.