Abstract: A first magnetic material film is deposited on a support, a groove is etched in the first magnetic film which is shaped like a figure eight, a double coil is formed and is wound respectively around the two central pole pieces. An insulating material layer is deposited and etched in step form, the step having a side facing the central channel. An magnetic film is deposited on the thus etched step, and the film is etched so as to only leave a wall perpendicular to the plane of the films. This is followed by the deposition of a magnetic film and then a protective layer, the assembly being divided off so as to expose two pole pieces separated by an air gap.

Abstract: The invention relates to a process for the positioning of an interconnection line on an electric contact hole in an integrated circuit. According to the invention, one or more conductive layers forming a conductive covering are deposited on the complete integrated circuit. The first conductive layer is deposited by an isotropic process. The interconnection line to be produced is then masked by a resin layer, followed by the successive etching of each conductive layer. Finally, an overetching of these conductive layers is effected in the electric contact hole, followed by the elimination of the resin.

Abstract: An optoelectronic device for reading data contained on the magnetic surface f a carrier comprises a source (SLP.sub.i) for emitting a beam of polarized light and means (MDK.sub.i) for detecting the angle of rotation of the polarization plane of the light. An optical focusing lens is provided for focusing onto a large observation field to enable simultaneous viewing of a plurality of tracks and a plurality of data on each track. Projection lenses (MPROJ.sub.i) enable projection of the image of the surface viewed by the optical means onto a plane P where optoelectronic transducers (TRPE.sub.ij) have been set up. The transducers may be arranged in a matrix or along a straight line.

Abstract: Transducer intended for read/write functions on a magnetic data carrier wherein the data is contained within a plurality of tracks. The transducer includes a magnetic circuit formed by two pole pieces separated by a gap parallel to the carrier, having its larger dimensions perpendicular to the direction of travel of the data of a track and a winding coupled magnetically to this circuit.The larger dimension of the gap varies depending on the nature of the function performed by the transducer. At least one thin layer of magnetic material is deposited across the pole pieces at each outer edge thereof and spaced from each other. The magnetic layers may be deposited in recesses formed in the pole pieces. The pole pieces may be constricted and include thin magnetic layers deposited on the lateral surfaces to channel magnetic flux lines.

Abstract: Transducer intended for read and/or write functions on a magnetic data carrier wherein the data is contained within a plurality of tracks. The transducer includes a magnetic circuit formed by two pole pieces separated by a gap parallel to the carrier, having its larger dimension perpendicular to the direction of travel of data on a track and a winding coupled magnetically to this circuit. The transducer is characterized in that it comprises means associated with the pole pieces situated at either side of the gap as seen in the direction of its larger dimension, for channelling the magnetic flux emitted by the immediate magnetic surroundings of the track of the carrier read by the transducer.

Abstract: To reduce the proportion of rejects resulting by reasons of short circuits in the manufacture and use of miniaturized multilayer circuits and to improve the electric efficiency, there is inserted between each conductive layer of low resistance and each insulating layer of high thermal stability, a very thin layer of a conductive material, preferably non-magnetic, of high resistivity and of crystallographic reference at least compatible with respect to the first conductive material and of low or negligible thermal expansion in the range of temperatures to which the circuits are submitted both during manufacture and use.

Abstract: A credit card or security card data processing system employing portable ds including data processing means in each card adapted to be coupled to a data processing station having its own data processing means. In each card a part of the data processing means is formed by magnetic bubble elements at least one of which is a memory. The magnetic bubble elements are formed in a layer of magnetic material which has a propagation track thereon and which is positioned between a pair of magnet elements which establish a polarizing field perpendicular to the layer. The operating station includes orthogonal conductive coils arranged to set up a rotatable magnetic field which is applied to the magnetic layer causing the bubbles to be attracted by magnetic poles in the propagation track. A magnetoresistive member senses movement of the bubbles.

Abstract: A magnetic transducer for reading and/or writing data contained on a carrier comprises two thin magnetic layers constituting the first and second pole pieces of the transducer. The layers are superimposed and magnetically coupled at one end and arranged at the other end adjacent the carrier, substantially perpendicular to the latter to form an air-gap to establish a magnetic circuit for the transducer. A coil is disposed between the thin magnetic layers. The coil is of thin conductive layers superimposed in a direction perpendicular to the plane of the magnetic layers and separated from each other by thin electrically insulating layers. The coil comprises windings of a number of turns N.sub.1 and N.sub.2 adapted to be traversed respectively by currents I.sub.1 and I.sub.2, the coefficients of mutual magnetic coupling of each of the thin conductive layers of each of the two windings with the downstream pole piece being respectively designated by L.sub.i1 and L.sub.

Abstract: A magnetic printing process and multicopy magnetic printing machine employing this process is disclosed. The machine comprises a magnetizable carrier 2, magnetic recording transducers 8, an applicator 10 for coating a developer product onto the carrier, a device for application of the carrier coated with the said developer product onto a document 12 which is to be printed and finally a device 16 for erasing the magnetized areas. In accordance with the invention, the developer product utilized contains magnetic particles which are formed by grains whose dimensions are of the order of those of the elementary magnetized areas. The imprint on the document is then produced by pressing.

Abstract: A magnetic transduction device for reading and/or writing of data contained on a magnetic support such as a disc or magnetic tape comprises a magnetic circuit formed by two thin superposed magnetic layers magnetically coupled at one end and forming an air gap at the other end, and a coil between said thin magnetic layers formed by thin conductive layers separated by thin insulating layers. At least one of the thin conducting layers comprises at least one magnetoresistance.

Abstract: A process for generating a magnetic induction field within a magnetic medium. A magnetic excitation field and a selection wave are caused to act simultaneously at each point on a path of at least one non-saturated portion of the magnetic medium, in such manner as to modify the magnetic properties of the medium at this point by degrading them and thus producing therein the induction field. The process is applicable to devices for generating a magnetic field utilized in magnetic data recording systems, wherein the magnetic medium is of a "degraded type".

Abstract: To reduce the proportion of rejects resulting by reasons of short circuits in the manufacture and use of miniaturized multilayer circuits and to improve the electric efficiency, there is inserted between each conductive layer of low resistance and each insulating layer of high thermal stability, a very thin layer of a conductive material, preferably non-magnetic, of high resistivity and of crystallographic reference at least compatible with respect to the first conducting material and of low or negligible thermal expansion in the range of temperatures to which the circuits are submitted both during manufacture and use.

Abstract: A portable credit or identity card or the like incorporates magnetic bubble elements. The bubble elements comprise a layer of magnetic material capable of containing magnetic bubbles and which is provided with a propagation track and a means for detecting the bubbles. Two flat permanent magnets arranged on either side of the magnetic layer generate a magnetic polarizing field perpendicular to the layer. The bubble element forms the memory which contains the identity code for the card.

Abstract: A carrier for magnetic data recorded therein by perpendicular recording comprises a non-magnetic substrate having at least one substantially plane surface provided with a magnetic data layer of an anisotropic magnetic material having its axis of easy magnetization perpendicular to the said plane surface, and includes an additional layer of an anisotropic magnetic material whose axis of hard magnetization is parallel to the said plane surface. An intermediate non-magnetic, insulative coupling layer may be provided to maximize magneto-static coupling between the layers while minimizing energy exchanges therebetween. A further non-magnetic sub-layer may be provided directly on the plane surface of the substrate to assure good adhesion of the additional layer to the substrate and isolation thereof from the magnetic layer.

Abstract: A platform for supporting at least one magnetic transducer for reading from and/or recording on a data carrier. The platform is supported from a carrier arm adapted to position the platform over the data carrier which may be a multi-track disc. The magnetic transducer is supported in the lower face of the main body of the platform. The lower face includes a plurality of skids and one or more grooves which receive a rigid strut for suspending the platform over the carrier. The strut is secured in the groove(s) with the plane of the strut passing through the center of gravity of the platform. The strut may be secured to a frame surrounding the platform which in turn may be secured to a further concentric frame also surrounding the platform. The strut includes a constriction located at the virtual axis of rotation or axis of oscillation of the platform and at which point the cross-sectional area of the strut is at a minimum.

Abstract: A method and apparatus for reading data defined by a plurality of magnetic elements which emit respective predetermined external magnetic fields consists in subjecting an anisotropic magnetoresistive device carrying a substantially constant electrical current to the effect of the external magnetic fields, polarizing in said magnetoresistive device by a magnetic polarizing field in such a way that the direction of magnetization and the axis of easy magnetization of the magnetoresistive material of the said device form a given angle between them, defining the maximum desired value of the said external magnetic fields to which the said magnetoresistive device will be subjected, and making the value of the said angle correspond substantially to the modulus of the sum of the said maximum desired value of external magnetic field and the magnitude of the demagnetizing magnetic field which is set up by the said magnetoresistive medium in response to the said external magnetic field having the said maximum desired val

Abstract: A magnetic transducer and method of operation is disclosed for removing the effect of interference magnetic fields present when detecting information magnetically coded on a carrier. The transducer is provided with a magnetoresistive compensating element disposed to develop a voltage in response to the interference magnetic fields equal to that developed across a magnetoresistive detecting element; however, the compensating element is positioned out of the magnetic leakage field of the coded information.

Abstract: A magnetic transducer and method of operation is disclosed for removing the effect of interference magnetic fields present when detecting information magnetically coded on a carrier. The transducer is provided with a magnetoresistive compensating element disposed to develop a voltage in response to the interference magnetic fields equal to that developed across a magnetoresistive detecting element; however, the compensating element is positioned out of the magnetic leakage field of the coded information.

Abstract: Fringing magnetic fields established by magnetic bars having parallel longitudinal axes are read from documents, such as checks, to determine a code on the document. The fringing fields extend in opposite directions to indicate the code. An array of magnetoresistive elements responsive to a DC energizing current is included so that at least one of the elements is provided for each of the fields. An alternating magnetic field of predetermined frequency and phase is coupled to each of the elements by a conductor that is effectively a single turn coil. The alternating magnetic field is superimposed on the fringing field so that the two fields are combined in each element to modulate the DC energizing current. The predetermined phase is compared with the phase of the modulated current to provide an indication of the fringing field direction and of the code.

Abstract: To reduce the proportion of rejects resulting by reasons of short circuits in the manufacture and use of miniaturized multilayer circuits and to improve the electric efficiency, there is inserted between each conductive layer of low resistance and each insulating layer of high thermal stability, a very thin layer of a conductive material, preferably non-magnetic, of high resistivity and of crystallographic reference at least compatible with respect to the first conducting material and of low or negligible thermal expansion in the range of temperatures to which the circuits are submitted both during manufacture and use.