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. 14, 2015
Filed:
Jul. 04, 2011
Shigeyoshi Netsu, Niigata, JP;
Fumitaka Kume, Niigata, JP;
Junichi Okada, Niigata, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
The length of the polycrystalline silicon rod () is measured with a tape measure, then the polycrystalline silicon rod () is hit with a hammer (), and this hammering sound is recorded in a recorder () through a microphone (). Then, an acoustic signal of the hammering sound is subjected to a fast Fourier transform and a frequency distribution is displayed. Furthermore, a peak frequency f is detected which shows the largest sound volume in the frequency distribution obtained after the fast Fourier transform. The relationship between the length (L) of the polycrystalline silicon rod and the peak frequency f is obtained, and the firmness of the polycrystalline silicon rod is determined on the basis of whether or not the peak frequency f is in a range of f≧1,471/L (region A).