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公开(公告)号：DE3061580D1
公开(公告)日：1983-02-17
申请号：DE3061580
申请日：1980-04-10
Applicant: IBM
Inventor： THOMPSON DAVID ALLEN , WORTHINGTON THOMAS KIMBER
Abstract: A magnetoacoustic system adapted to use as a keyboard can employ a serpentine acoustic delay line passing under a number of transducers which are activated simultaneously with a current pulse through the wire. Magnets adjacent to the wire generate magnetoacoustic pulses along the wire which arrive sequentially at a sensor at one end of the line. For each key on a keyboard at least two magnets are associated with each key position with one magnet affixed in position and one reciprocably movable towards and away from the wire in a response to actuation of the key. The magnet which remains close to the wire is used to provide a "location" signal indicating the location along the delay line provided by the wire by producing an acoustic pulse for that point on the wire for each clock pulse of current which passes through the wire. The second magnet located adjacent to the first magnet generates a pulse simultaneously with the other magnets when the current pulse passes through the wire, but it is delayed by the physical displacement along the wire, so it is received at a different time than the pulse from the other magnet. The data pulse can follow or precede the location pulse so long as the presence of one or both can be readily decoded. A three magnet key arrangement can be employed where it is desired to be able to use three positions per key.
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Patent Agency Ranking
公开(公告)号：NO801801L
公开(公告)日：1980-12-30
申请号：NO801801
申请日：1980-06-17
Applicant: IBM
Inventor： THOMPSON DAVID ALLEN
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公开(公告)号：FI802059A
公开(公告)日：1980-12-30
申请号：FI802059
申请日：1980-06-27
Applicant: IBM
Inventor： THOMPSON DAVID ALLEN
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公开(公告)号：DE2555298A1
公开(公告)日：1976-07-29
申请号：DE2555298
申请日：1975-12-09
Applicant: IBM
Abstract: A magnetizable fluid which serves as a display liquid and which includes a suspension of colloidal magnetic particles is used in a display device. The magnetic fluid is opaque to provide optical contrast. A host liquid is substantially immiscible with the display liquid. The display liquid is carried in a reservoir section which is distributed about the periphery of a display field in the reservoir. Each propagation line of the display field is provided with a bubble generator, which passes bubbles by the input end of each line. A bubble switch coil draws selected bubbles across a gap to reach the associated propagation line in response to a signal impressed on the coil. A uniform rotating magnetic field is provided by a permanent magnet beneath the display or by orthogonal magnetic coils.
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公开(公告)号：DE2422927A1
公开(公告)日：1975-01-23
申请号：DE2422927
申请日：1974-05-11
Applicant: IBM
Inventor： BAJOREK CHRISTOPHER HENRY , THOMPSON DAVID ALLEN
Abstract: Elimination of crosstalk in an integrated array of magnetoresistive reading heads by the use of regions of high coercivity material between the active areas of closely spaced magnetoresistive sensors so as to prevent flux coupling between such closely spaced sensors.
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公开(公告)号：DE2241906A1
公开(公告)日：1973-05-03
申请号：DE2241906
申请日：1972-08-25
Applicant: IBM
Inventor： ALMASI GEORGE STANLEY , KEEFE GEORGE EDWARD , LIN YEONG SHOW , THOMPSON DAVID ALLEN
Abstract: 1369573 Magnetic storage devices INTERNATIONAL BUSINESS MACHINES CORP 28 Sept 1972 [26 Oct 1971] 44737/72 Heading H3B A sensor of small magnetic fields, such as bubble domains, comprises a magneto-resistive element whose dimensions are sufficiently small, e.g. 200 angstroms thick, 7À5 microns long and 5 microns wide, as to have both a uniaxial anisotropy field imparted during manufacture, and a shape anisotropy field determined by the relationship of its unequal length and width dimensions, the two anisotropy fields being mutually perpendicular and the larger of the two fields being substantially perpendicular to the magnetic field to be detected. As shown in Fig. 1A, a rectangular magnetoresistive element 18 is associated with an orthoferrite or garnet sheet 10 in which bubble domains are propagated by the combination of a permalloy T and I bar pattern and an in-plane rotating magnetic field H. A rectangular magnetoresistive sensor element 18 formed, e.g. of permalloy; and located on or adjacent to the sheet 10, is connected to a constant current source 20 by leads 19, changes of resistance due to magnetic field proximity being indicated to a utilization means 22 as a change of voltage Vs. The sensor element has an easy axis of magnetization E.A. transverse to its length, and has a shape anisotropy field greater than the uniaxial anisotropy field so that the magnetization vector M is normally directed along the length of the element. When a bubble domain 30, Fig. 1B, is moved into a position adjacent the sensor element 18, the external field H B of the domain coupled with the element causes rotation of its magnetization vector M and consequential change in the element resistance. It is stated that the use of both uniaxial and shape anisotropy enhances the detection sensitivity to small magnetic fields. In a modification. Figs. 2A and 2B, the sensor element is arranged so that it is parallel to an external domain field H B along its length dimension. As before the easy axis of magnetization E.A. extends across the width of the element, but in this case the shape anisotropy field is less than the uniaxial anisotropy field so that the normal position of the magnetization vector M is parallel to the easy direction of magnetization. This vector is rotated towards the length dimension of the element by an adjacent bubble domain 30 as shown in Fig. 2B. The sheet 10 is subjected to a bias field H z derived from a permanent magnet, an energized coil or an adjacent magnetic sheet. The sensor may be used to read out a pattern of domain reversals extending across a moving magnetic tape, Fig. 3A (not shown), in which case the sensor element is mounted with electrical connections on an insulating substrate. Such an element is formed by evaporation deposition on a magnetic sheet or insulating substrate in the presence of a magnetic field with the subsequent selective formation of electrical connections by masking, electroplating and etching.
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