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:
Apr. 01, 1997
Filed:
Jan. 27, 1995
Kazuhiro Nobori, Haguri-gun, JP;
Ryusuke Ushikoshi, Tajimi, JP;
Koichi Umemoto, Toyota, JP;
Atsushi Sakon, Nagoya, JP;
Yusuke Niiori, Inuyama, JP;
Masahiro Murasato, Chita, JP;
NGK Insulators, Ltd., , JP;
Abstract
A ceramic heater composed of a ceramic substrate and a resistant heating element embedded within the ceramic substrate along a predetermined planar pattern is obtained by holding a convolution of a spiral-coiled high melting metallic filament in the above predetermined planar pattern and heat-treating the convolution at a temperature not higher than a primary recrystallization commencement temperature of the high melting metal under a non-oxidative atmosphere to provide the resistant heating element, embedding the resulting resistant heating element within a ceramic shaped body, and then, sintering the ceramic shaped body. In a preferred embodiment, the resistant heating element is a convolution of a spiral coil, the number of coils per a unit length of said convolution is set at a predetermined value in each of defined domains of the ceramic heater, and when the number of coils per a unit length of the convolution is determined, the relation of the maximal value, the minimal value and the mean value, of all the determined numbers of coils in the above domains, satisfies the formula: