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:
Sep. 12, 1989
Filed:
Sep. 10, 1987
Kazumi Kuriyama, Yamansahi, JP;
Shigeru Kono, Yamansahi, JP;
Yutaka Takasu, Yamansahi, JP;
Chiharu Koshio, Yamansahi, JP;
Kazuhiko Nagata, Yamansahi, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
An apparatus for detecting faults on the surface of a resist master disc and for measuring the thickness of the resist coating layer includes a single light source for generating a laser beam for inspection of the master disc, a first separator for separating the laser beam into a first laser beam which is used for the detection of faults, and a second laser beam which is used to measure the thickness of the resist coating layer. The second laser beam is further separated into two laser beams one of which is irradiated on the surface of the resist coated master disc at a given angle of incidence. The detection of faults on the surface of the master disc is performed by detecting a level change of the quantity of reflection light of the first laser beam from the resist master disc, and the measurement of the thickness of the resist layer is performed by using a ratio between quantities of two laser beams obtained from the second laser beam one of which is detected after being reflected by the surface of the resist master disc.