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:
Nov. 07, 2000
Filed:
Dec. 01, 1997
Tatsuo Nagasaki, Hirakata, JP;
Ken Shimono, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka-fu, JP;
Abstract
An inspecting method for inspecting foreign substances, comprising projecting beams from an illumination system arranged above a light-permeable body to be inspected with an angle of incidence of a first elevation angle onto an upper face of the body, and receiving a reflecting light and a scattering light generated by the beams with a photodetecting angle of a second elevation angle by a photodetecting system. The method further comprising, before the beams are projected, setting a width of the beams of the illumination system to be not larger than w calculated according to an expression w<2* sin .alpha.*t{tan[sin.sup.-1 {sin(90.degree.-.alpha.)/n}]-tan[sin.sup.-1 {sin(.theta.-90.degree.)/n}]} from the angle of incidence .alpha., the photodetecting angle .theta., a thickness t of the body and a refractive index n of the body to a substance over the body.