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:
Apr. 23, 1985
Filed:
May. 16, 1983
Jan Verweel, Eindhoven, NL;
Hinne Zijlstra, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
In a first method, a meander-shaped coil (20,21) is provided on each side of the mask (7) having apertures (9). The coil (21) is oriented perpendicularly relative to the coil (21). If a current flows through the coils (20,21) in the correct direction, a magnetic quadrupole is formed along the circumference of each aperture (9). In a second method, a holder (30,31) with permanent magnetic strips (32) is provided on each side of the mask (7). The strips (32) in the one holder (30) are oriented perpendicularly relative to the strips in the other holder (31). A coil 40 is provided around the holders 30 and 31 with which a decaying magnetic alternating field, is generated which initially drives the material of the mask (7) on both sides of the hysteresis curve into saturation. After the decay of said alternating field a magnetic quadrupole is present along the circumference of each aperture (9).