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:
Jan. 30, 1979
Filed:
Sep. 12, 1977
Hewson N King, Redhill, GB;
Julian P Scott, Brighton, GB;
U.S. Philips Corporation, New York, NY (US);
Abstract
An electron image projection mask consisting of an optical mask comprising a transparent substrate, bearing an opaque mask pattern disposed on the substrate, a transparent coating extending over the mask pattern and the areas of the substrate exposed through the apertures in the opaque mask pattern, and a metal image extending over the transparent coating. The metal image has a pattern corresponding to the apertures in the opaque mask pattern, the optical density of the metal image being such as to reduce the average light transmission through the apertures in the mask to a value between 25 and 80% of the average light transmission of the apertures in the absence of the metal image. Also, a method of producing the electron image projection mask.