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. 19, 1991
Filed:
Jan. 02, 1990
William J Harrold, Derry, NH (US);
Joseph A Sansone, Rehoboth, MA (US);
Joseph W Bonfiglio, West Newton, MA (US);
Seung K Kim, Shrewsbury, MA (US);
Raytheon Company, Lexington, MA (US);
Abstract
A magnetic field sensing and canceling circuit for use with a cathode ray tube (CRT) has a closed loop system consisting of flux gate sensors to measure external magnetic fields and magnetic field cancellation coils around the perimeter of the faceplate of the CRT to cancel the fields and thus minimize color and positional ac image distortion. The coils are mounted on an enclosure fabricated of a high permeability material and are positioned around the perimeter of the CRT's faceplate. Four of the coils are parallel to the top, bottom, and sides of the enclosure opening and a fifth coil is wound around the enclosure adjacent the CRT faceplate. The magnetic flux gate sensors provide output signals that are functions of the detected fields. These signals control the current in the magetic field cancellation coils and thus control the cancellation fields.