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:
Jun. 25, 2002
Filed:
Apr. 29, 1994
Barret Lippey, Gardena, CA (US);
Darrell A. Gleichauf, Redondo Beach, CA (US);
Weldon S. Williamson, Malibu, CA (US);
Hughes Electronics Corporation, El Segundo, CA (US);
Abstract
Cryofilm/organic contaminants are removed from cryogenically cooled surfaces such as spacecraft cryo-telescope mirrors by sputtering and chemical reaction with a low energy plasma having an average ion energy of not more than about 30 eV, and preferably in the approximate range of 5-20 eV. When the reactive plasma's freezing point is higher than the temperature of the surface to be cleaned, the cryofilm and embedded hydrocarbons are first removed with a non-reactive plasma having a freezing point less than the surface temperature, the reactive plasma is then used to remove residual organic contaminants left on the surface by chemical reaction, and finally another inert plasma is applied to remove reactive plasma frozen to the surface; the two inert plasmas are preferably formed from the same gas.