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. 31, 1995
Filed:
Dec. 04, 1992
Hiroo Kanamori, Yokohama, JP;
Akira Urano, Yokohama, JP;
Haruhiko Aikawa, Yokohama, JP;
Shinji Ishikawa, Yokohama, JP;
Chisai Hirose, Yokohama, JP;
Masahide Saito, Yokohama, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
In the first step, a fuel and raw material gases are fed to burner while flames from the burner scan a Si substrate. Synthesized fine glass particles are deposited on the substrate to form a first porous vitreous layer to be an under cladding layer. In the second step, the first porous vitreous layer is heated by the flames. A bulk density of an upper part of the first porous vitreous layer is raised to 0.3 g/cm.sup.3. Having a raised bulk density, this upper part functions as a shield layer against GeO.sub.2. In the third step, a second porous vitreous layer, to be a core layer, is deposited uniformly on the first porous vitreous layer. In the fourth step, the first and the second porous vitreous layers are sintered. In this case, the shield layer with a higher bulk density hinders the GeO.sub.2 component which has evaporated from the second porous vitreous layer from diffusing into the first porous vitreous layer.