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:
Jun. 26, 2001
Filed:
Oct. 08, 1999
Yoshiaki Komuro, Nishinomiya, JP;
Hidehisa Tachibana, Osaka, JP;
Sansha Electric Manufacturing Company, Limited, Osaka, JP;
Abstract
A metal material is placed in a crucible,An inverter,outputs a voltage amplitude-modulated with a low frequency signal. The output voltage is used to RF induction heat the crucible. A photodiode,receives light emitted by the metal material in the crucible and develops a received-light-representative signal. A high-pass filter,extracts, from the received-light-representative signal, a frequency component having a frequency above the frequency of the low frequency signal. A comparator,develops an output signal when the output signal of the high-pass filter exceeds a reference signal provided from a peak sample-and-hold circuit,to which the output signal of the high-pass filter is applied as an input thereto.