| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem where, whereas rapid temperature rise such as quickening the starting in a cold start is required for a ceramic heater for expressing respective functions, a porous ceramic layer is separated by the difference of thermal expansion between a ceramic heater element and the porous ceramic layer when a heater part rapidly raises temperature because the thickness of the porous ceramic layer formed on an element surface is large. SOLUTION: Two or more of the porous ceramic layers are formed at a tip of a flat or cylindrical ceramic heater element with a heating element embedded therein, and ends of the ceramic layers are each formed into a step-like or tapered shape. Alternatively, at least a part of an end of the innermost ceramic layer is exposed relative to ends of the other ceramic layers. COPYRIGHT: (C)2006,JPO&NCIPI
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