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:
Feb. 21, 1995
Filed:
Dec. 31, 1992
Matthew B Baillie, Emmaus, PA (US);
Ming-Chung Jon, Princeton Junction, NJ (US);
AT&T Corp., Murray Hill, NJ (US);
Abstract
This invention embodies a method and apparatus for determination of surface resistivity (.rho.) of materials to be used for a desired purpose. The surface resistivity is obtained by measuring surface resistance (R) of at least one square area of the material, and converting the surface resistance into a surface resistivity (.rho.) by a correction factor K (K=.rho./R) whenever the total area of the material is greater than three square area. The surface resistance is measured by placing a pair of square electrodes, spaced from each other a distance equal to the side of the square, applying measuring voltage potential to the electrodes, and determining the surface resistance of said at least one square area. The surface resistivity of materials of any size can be obtained by multiplying the surface resistance value by a correction factor determined for the size of the material being investigated. The surface resistivity may be confirmed by cutting out three square long areas of the material and measuring the surface resistivity of each separate three square area, resulting in simultaneous surface resistivity measurement. The maximum error in applying the correction factor to convert the resistance into the surface resistivity is less than 25 percent, which is small compared to those produced by the conventional surface resistivity meters available on the market, which measure the resistance in increments of 10.