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:
Oct. 29, 1996
Filed:
Mar. 23, 1995
Frederick W Dynys, Chagrin Falls, OH (US);
Thomas G Parham, Gates Mills, OH (US);
General Electric Company, Schenectady, NY (US);
Abstract
An optical interference filter produced on a vitreous, light transmissive substrate, such as an electric lamp envelope, includes a plurality of alternating layers of tantala and silica in which each tantala layer includes titania in an amount of less than about 10 mole % whereby the microstructure of the tantala layers is controlled during subsequent crystallization and extrinsic stress in the tantala layers is reduced. Rather than or in addition to including titania in each tantala layer, the present invention additionally contemplates placing at least some of the tantala layers in contact with a titania layer (pre-layer and/or post-layer) whereby the microstructure of the tantala layers is controlled during subsequent crystallization and extrinsic stress in the tantala layers is reduced. The optical interference filters are produced by a process comprising depositing a plurality of alternating layers of tantala and silica on a vitreous, light transmissive substrate from respective precursors thereof by CVD, preferably LPCVD, to form a coated substrate. The filter may then be heated for a time and to a temperature effective to crystallize the tantala, preferably to a temperature ranging from about 550.degree. to about 800.degree. C. and holding same within that temperature range for at least about one hour.