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:
May. 25, 1993
Filed:
Sep. 10, 1991
Atsuharu Yamamoto, Kawasaki, JP;
Yuji Maruyama, Tokyo, JP;
Hidehiko Kawakami, Tokyo, JP;
Hideaki Kawamura, Kawasaki, JP;
Masaaki Nakashima, Osaka, JP;
Hidemi Takahashi, Zama, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A pattern inspection system for inspecting a pattern of a land for a through-hole formed in a printed board. In the system there are included a first illumination device for optically illuminating the printed board, a second illumination device for illuminating the printed board with light modulated at a predetermined period and an image pickup responsive to reflection light and transmission light from the printed board due to the first and second illumination devices to photoelectrically convert the printed board into a gray level image. The gray level image is converted into a bi-level image by a bi-level conversion device and then converted into an edge image by an edge detecting device. The edge image is expanded and contracted by predetermined amounts so as to obtain a through-hole image corresponding to the through-hole. A defect detecting device detects a defect of the pattern of the printed board on the basis of the through-hole image and the bi-level image from the bi-level conversion device.