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:
Jan. 26, 1993
Filed:
Oct. 15, 1991
Applicant:
Inventors:
Masaaki Niwa, Hirakata, JP;
Shozo Okada, Kobe, JP;
Assignee:
Matsushita Electric Industrial Co. Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
250307 ; 250306 ;
Abstract
There is provided a method for determining the presence of an insulating film on the surface of an electrically conductive material. In this method, an electrically conductive probe is brought into contact with the surface of a specimen, and a voltage is applied between the probe and the surface of the specimen. A tunneling current which flows through the probe is detected and amplified, while controlling the distance between the probe and the surface of the specimen to ensure a substantially constant tunneling current.