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. 09, 1982
Filed:
Aug. 25, 1980
Peter K George, Morgan Hill, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A field-access bubble memory chip has a plurality of permalloy elements overlying an insulating layer. The permalloy elements are configured and positioned to define a plurality of paths for propagating magnetic bubbles under the influence of a Z bias magnetic field and a rotating XY magnetic drive field. A first portion of the paths are located in control function areas of the chip and a second portion of the paths are located in a storage area of the chip. The period of the permalloy elements in the control function areas is substantially greater then the period of the permalloy elements in the storage area. The thickness of the insulating layer immediately beneath the permalloy elements is less in the storage area than in the control function areas. This difference in thickness is sufficient so that the propagation margins for magnetic bubbles in the control function areas and in the storage area are substantially equal. Thus the bit density in the storage area can be significantly increased by reducing the period of the elements therein without any net reduction in the overall margin of the chip.