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:
Jul. 07, 1981
Filed:
Sep. 11, 1979
Applicant:
Inventors:
Koichi Karasaki, Hadano, JP;
Yasuhiko Hara, Yokohama, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01B / ;
U.S. Cl.
CPC ...
356378 ; 356394 ;
Abstract
In order that a slight positional deviation of a plated through hole such as having no substantial effect on the function of wiring should not be optically detected as a defect in a printed wiring board, the plated through hole is recognized as a part of the wiring pattern by making light representative of the plated through hole nearly equal in intensity to reflected light from the wiring pattern. This is achieved by illuminating the printed wiring board with light from the back side or by placing a reflector on the back side of the printed wiring board.