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:
Nov. 03, 1992
Filed:
Jul. 11, 1991
David Shafer, Fairfield, CT (US);
Ian Powell, Gloucester, CA;
General Signal Corporation, Stamford, CT (US);
Abstract
A photolithographic projection optical system comprising: a source of exposure energy for generating a beam of energy; an optical element located in the path of the beam for receiving the beam of energy and passing the beam therethrough; a refractive lens assembly located in the path of the portion of the beam for receiving and transmitting the beam of energy, the refractive lens assembly comprising at least one meniscus lens, a plano-convex lens, and an air gap disposed between the meniscus lens and the plano-convex lens; a reticle element located in the path of the portion of the beam, the reticle element having a uniform thickness and being positioned for permitting the beam to pass through the thickness and through the lens assembly to the optical element. Alternatively, the air gap of the refractive lens assembly can be replaced with a glass layer having an index of refraction that is lower than both the meniscus lens and the plano-convex lens.