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:
Jul. 04, 1989
Filed:
Dec. 21, 1987
Johan F Witte, Amsterdam, NL;
Stork Veco B.V., , NL;
Abstract
Described, is a membrane and its method of manufacturing which membrane is an electroformed metal foil having areas of high perforation density (higher than 150000/cm.sup.2) and unperforated areas and in particular also unperforated areas having greater thickness than the other areas. The membrane is produced in a process comprising a two step photolithographic procedure in which canals formed in the first photolithographic step are used to ensure good vacuum contact during the second photolitographic step in which the high density pattern is formed in the photolacquer used. The invention also relates to a separation device incorporating one or more membranes according to the invention.