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:
Dec. 30, 1997
Filed:
Aug. 22, 1996
Noboru Kimura, Gunma-ken, JP;
Ryouji Iwai, Gunma-ken, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
An improvement is proposed in the method for the preparation of a ceramic heater consisting of a substrate of boron nitride, patterned graphite layer thereon as an electric resistance heater element and an overall cladding layer of pyrolytic boron nitride formed on allover the surface after pattern-wise engraving of the graphite layer and the substrate in order to enhance the stability of the cladding layer against crack formation or exfoliation. The improvement is achieved by limiting the depth of engraving not to exceed 200 .mu.m or chamfering and rounding of the edged and recessed ridge lines formed by engraving so that the cross sectional profile is in a smooth contour having a radius of curvature not smaller than 0.5 mm.