Browse Prior Art Database

Bubble Domain Compressor Sensor

IP.com Disclosure Number: IPCOM000086990D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 39K

Publishing Venue

IBM

Related People

Chang, H: AUTHOR [+2]

Abstract

U.S. Patent 3,858,189 describes a bubble domain compressor-sensor in which a multiplied output signal is obtained each time an input bubble domain is received by the device. Each bubble domain in the idler of the compressor circuit therein is displaced to be adjacent to a bubble sensor, such as a thin-film magnetoresistive sensor. Thus, multiple bubble domains in the compressor provide output signals indicative of the input domain and the result is an amplified output signal. The present invention provides compressor design variations which expand the operating margin of the compressor-sensor of U.S. Patent 3,858,189.

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Bubble Domain Compressor Sensor

U.S. Patent 3,858,189 describes a bubble domain compressor-sensor in which a multiplied output signal is obtained each time an input bubble domain is received by the device. Each bubble domain in the idler of the compressor circuit therein is displaced to be adjacent to a bubble sensor, such as a thin-film magnetoresistive sensor. Thus, multiple bubble domains in the compressor provide output signals indicative of the input domain and the result is an amplified output signal. The present invention provides compressor design variations which expand the operating margin of the compressor-sensor of U.S. Patent 3,858,189. In particular, the designs shown above use skewed idler compressors to enhance the collapse margin due to alignment of opposite poles and eliminate channels of parallel magnetic bars to avoid strip-out of bubble domains in the device.

The skewed-idler compressor of Fig. 1 focuses on the critical choice by a bubble initially at position 2 between competing poles 3 and 3'. Correct idler operation in the absence of an input bubble requires the bubble to jump the gap to 3 rather than slide down the permalloy to pole 3'. This choice is influenced by this improved design as follows: In contrast to conventional idler circuits, the poles of any idler cell in Fig. 1 are truly independent of those of the adjacent cell. Therefore, pole positions and strength may be freely adjusted. For example, pole 3 (relative to pole 3') may be made as strong as desired and its gap to position 2 may be chosen freely without affecting pole 3'. In the compressor of Fig. 1, pole position 3' may be made significantly much farther from position 2 than is pole 3.

Thus, although pole 3' is not separated from pole 2 by a gap, suitable adjustment of strength, position and gap size of pole 3 should make pole 3 clearly preferred by the bubble initially at position 2, in the absence of an input bubble. Since poles 3 and 3' in the circuit of Fig. 1 enjoy much greater separation, there is considerably less danger of strip-out between the competing poles.

The only competing poles that will affect the actual operation of this circuit are the desired poles 3 and 3', with no other critical choices required of the idler bubble during a cycle of rotating drive field H(xy). This removes the possibility of failure due to the bubbles' selection of undesired poles during other phases of the drive field, and also avoids the possibility of extraneous strip-out between the desired pole position and an undesired competing pole.

Pole 3', again a transition pole not part of the adjacent idlers, is at the bottom of a chevron bar, at the lowest point of the compressor. The idler bubbles during inter-cell transitions will be carried to the bottom of the compressor, and are now much more accessible for such purposes as sensing than are the idler bubbles in the prior art structures. A sensor line separate from the compressor will not create unde...