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:
Mar. 29, 1994
Filed:
Oct. 01, 1992
Kabushiki Kaisha Kobe Seiko Sho, Kobe, JP;
Abstract
When evaluating defects, etc. of a sample by measuring thermal expansion displacement on the surface of the sample, which is produced by irradiating thereto an excitation beam of which intensity is cyclically modulated, a measuring beam having the displacement frequency F.sub.1 is irradiated to the vibrating surface of the sample, and the reflection beam is interfered with a reference beam having the frequency F.sub.2. The beat wave signal E.sub.1 (Beat frequency F.sub.b =F.sub.1 -F.sub.2) is converted to a binary signal E.sub.2. Then, the sample is evaluated by signals which are obtained by giving a suitable processing to the binary signals. In addition, the optic axes alignment is eliminated by utilizing the excitation beam itself concurrently as measuring beam.