Societe D'applications Generales D'electricite Et De Mecanique Sagem

Societe D'applications Generales

Michel Poirier

Francis Compagnon

Xavier Boutin

A magnetic bubble memory has a reading zone with thin detection elements, coated with an insulating layer which carries thick bubble propagation patterns of high magnetic permeability material, and a bubble stretching zone also including thick propagation patterns of shapes such that the rotating field of the device causes the bubbles to progress along the patterns. The device further includes, out of the detection zone, additional thin localized elements of high magnetic permeability material having a thickness much lower than that of the patterns, obtainable by photolithography and located at the same level as the thin detection elements. When located in the stretching zone, the thin patterns are arranged to cooperate with thick patterns so that the voltage well generated by the rotating field of the device has a substantially constant value while moving along the thick patterns.

Magnetic bubble memory device

A magnetic bubble memory device comprises a common package accommodating a lurality of pairs of memory chips. In each pair, the two chips have bubble propagation patterns in confronting relation which are mirror images of each other and additionally angularly offset by 180. Electrical connecting leads between the chips and the outside of the package are carried by insulating films located between the confronting chips. Coils located in the package create a bias magnetic field which is common to all chips. The coils for driving bubbles along the patterns are also common to all chips.

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Eragny, France

Michel Poirier