Sperry Rand Corporation

Marlin M Hanson

Roger Edward Lund

Ernest J Torok

Stanley J Lins

John M Gorres

A method of and an apparatus for improving the selective positioning of single wall domains or bubble domains in a bubble domain memory system is disclosed. The method includes the use of slotted intersecting digit and word drive lines that form memory areas, each memory area being defined by the inside opposing edges of the slotted drive lines at each intersection. Each memory area has four quadrants, three of which are effectively optically blocked by an opaque shield--a bubble domain in the one unblocked quadrant provides the desired Faraday rotation of a plane polarized coherent light beam to generate a beamlet that is optically detected as a binary digital signal. The slotted drive lines are formed below the surface of the bubble domain supporting layer whereby the so-provided magneto static barriers prevent bubble domain sticking in a selected one quadrant of the four quadrants of the memory area and prevent bubble domain escape from the memory area itself.

Method of improving the operation of a single wall domain memory system

Defining the structuring of bubble domains in the magnetizable layer of a bubble domain memory plane is determined by modification of the magnetic characteristics of the magnetizable layer in the confinement area. The memory plane is comprised of a non-magnetic Gadolinium Gallium Garnet (GGG) layer which is a supporting substrate upon which is formed by the liquid phase epitaxy (LPE) method a magnetizable layer in which bubble domains are capable of being generated, sustained and moved about. Formed upon the bubble domain supporting magnetizable layer is a matrix array of conductive drive lines, the intersections of which define respective memory areas. In each memory area the position of the bubble domain in the magnetizable layer is determined by modifying the magnetic characteristics of the magnetizable layer in a confinement area as by an ion milling process. The ion milled confinement area along the line of the thickness gradient generates a perpendicular field H.sub.P that tends to prevent the bubble domain from escaping from the so-defined confinement area. The perpendicular field H.sub.P component that is generated by the thickness gradient produces a sharp potential minimum at the edge of the ion milled region. This potential minimum draws the bubble domain toward the edge of the thickness gradient whereby the bubble domain size may be expanded to fill the confinement area. Additionally, the confinement area may consist of a plurality of interconnected lobes each of which defines a given bubble position, each of which bubble positions may be utilized to define a memory position that may be utilized in an optical page composer of an optical data processing system.

Structuring of bubble domains in a bubble domain memory plane

Disclosed is an apparatus for and a method of propagating bubble domains along fixed guidance channel forming stripe domains by capturing them in moveable stripe domains and then moving the capturing moveable stripe domains. The memory plane comprises a non-magnetic Gadolinium Gallium Garnet (GGG) layer which is a supporting substrate upon which are successively formed by the liquid phase epitaxy (LPE) method: a first stripe domain layer, a first non-magnetic spacer layer; a bubble domain layer; a second non-magnetic spacer layer; a second stripe domain layer; and a third non-magnetic spacer layer upon which is formed the necessary propagation circuitry. The method of propagating the bubble domains involves forming fixed guidance channel forming stripe domains in the first stripe domain layer, orienting moveable stripe domains in the second stripe domain layer in a direction orthogonal to the direction of the fixed guidance channels, establishing bubble domains in the bubble domain layer at selected ones of each fixed guidance channel, moveable stripe domain intersection and finally oscillating the moveable stripe domains in a direction parallel to the fixed guidance channels by a time-varying, i.e., temporally changing, localized bias field gradient. A moveable stripe domain in a first position under a bias field gradient producing strip line captures a bubble domain, slowly moves the bubble domain a predetermined propagation direction under the strip line and along its associated fixed guidance channel into a second position under the strip line and then subsequently quickly moves back to its first position under the strip line allowing the bubble domain to escape therefrom leaving the propagated, escaped bubble domain in the second position under the strip line to be captured by a next adjacent downstream moveable stripe domain. Successive capture, propagate, escape operations propagate all the bubble domains along each capturing moveable stripe domain, in parallel, in the downstream propagation direction through the memory plane.

Bubble domain propagation using oscillating stripe domains

A light accessable transistor matrix (latrix) that utilizes an optical page composer having single wall domains, i.e., bubbles, in a layer of magnetizable material as the optical shutter or light valve is disclosed. The latrix is configured into an holographic memory system. The optical page composer is comprised of a magnetizable layer having orthogonal sets of D parallel digit lines and W parallel word lines, the DW intersections of which form DW memory areas. Each memory area has four quadrants defined by the intersecting digit line and word line. An opaque shield is oriented in each memory area for optically shielding a bubble except when in the exposed first quadrant within the memory area. Coincident current selection, e.g., concurrent half current selection, of one digit line and of one word line by half-select write signals permits the one fully selected memory area to be separately selected for the write operation. Full current selection of one word line permits the read operation to concurrently read all memory areas along the one fully selected word line. Optical read out of the stored data along a selected word line by a one-dimensional photosensor array is accomplished by a selective positioning of the associated bubbles in either the first or the fourth quadrant of the associated memory areas corresponding to the readout of a stored 1 or a stored 0.

Single wall domain latrix for optical data processing system

A method of and an apparatus for improving the selective positioning of single wall domains or bubbles in a memory system is disclosed. The method includes the use of slotted intersecting digit and word lines that are coated with a magnetic material of relatively high retentivity.

A method of improving the selective positioning of single wall domains or bubbles in a memory system is disclosed. The method includes the use of a predetermined stripline-magnetic layer separation and a drive current signal of a waveform having a relatively high initial amplitude and a relatively decreasing trailing amplitude.

Growing community of inventors

Cologne, MN, United States of America

Marlin M Hanson