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. 22, 1998
Filed:
Dec. 11, 1996
Atsushi Ozaki, Annaka, JP;
Masahiko Urano, Takasaki, JP;
Isamu Harada, Annaka, JP;
Tomohiro Kakegawa, Tomioka, JP;
Hideki Nakano, Sawa, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
A crystal pulling apparatus is disclosed which employs the Czochralski method. The crystal pulling apparatus is operated while a heater for heating a material melt in a crucible is controlled by the main controller of a main system. When maintenance of a heating state is disabled for some reason, a relay of a signal changeover circuit is switched so as to maintain the heating state under control of the backup controller of a backup system, thereby maintaining the material melt in a molten state. Thus, even when it becomes impossible for the main system to heat the material melt within the crucible, the material melt can be prevented from becoming solidified.