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. 14, 1993
Filed:
Dec. 27, 1991
Noboru Kato, Hadano, JP;
Izuo Horai, Odawara, JP;
Toshihiro Kimura, Fujisawa, JP;
Mitsuyoshi Koizumi, Yokohama, JP;
Hitachi Electronics Engineering Co., Ltd., Tokyo, JP;
Abstract
An apparatus for detecting extraneous substances on a glass plate includes a first light projecting system arranged above a plane under examination on a glass plate, the surface of which is irradiated with an S-polarized laser beam at a first elevation angle, a second light projecting system arranged above the surface thereof which is irradiated with a P-polarized laser beam at a second elevation angle greater than the first elevation angle, and a light receiving system for receiving scattered light from the surface irradiated with the laser beams respectively emitted from the first and the second light projecting system at an elevation angle smaller than the first elevation angle. The light receiving system is arranged on a side opposite to the direction of irradiation with the normal line set up at the laser beam irradiation point therebetween and the output level of the P-polarized laser beam is set in specific relation to the S-polarized laser beam.