Abstract: A sensor for a textured surface (e.g., a fingerprint) is provided. The sensor includes a flexible substrate and a flexible membrane supported above the substrate by one or more spacers. The sensor also includes multiple pressure sensor elements responsive to a separation between parts of the membrane and corresponding parts of the substrate. The membrane is conformable to the textured surface being sensed, so the variation in separation between substrate and membrane is representative of the textured surface being sensed. Such pressure sensors can be included in fingerprint authentication subsystems including associated integrated electronic circuitry (e.g., encryption, image processing, fingerprint matching, communication and/or location determination circuitry). Such subsystems can be included in various access control systems (e.g., smart cards and mobile electronics).

Abstract: A sensor for a textured surface (e.g., a fingerprint) is provided. The sensor includes a flexible substrate and a flexible membrane supported above the substrate by one or more spacers. The sensor also includes multiple pressure sensor elements responsive to a separation between parts of the membrane and corresponding parts of the substrate. The membrane is conformable to the textured surface being sensed, so the variation in separation between substrate and membrane is representative of the textured surface being sensed. A preferred sensor array arrangement has a set of parallel substrate electrodes on the substrate facing the membrane and a set of parallel membrane electrodes on the membrane facing the substrate, where the substrate and membrane electrodes are perpendicular. The sensor array is preferably an entirely passive structure including no active electrical devices, to reduce cost. Row and column addressing circuitry can be provided as separate units (e.g.

Abstract: A sheet film protective covering for different types of contour sensing devices is described. In a preferred embodiment, this covering is a mylar sheet film that is coated with a layer of a conductive material. The bottom surface of the mylar film is also preferably coated with a layer of an adhesive. The sheet film covering preferably is contiguous and serves the purpose, among other things, to protect the underlying surface of the pressure-sensing device from contaminants and from electrostatic discharge, as well provide force concentration during use.

Abstract: A sheet film protective covering for different types of contour sensing devices is described. In a preferred embodiment, this covering is a Mylar sheet film that is coated with a layer of a conductive material. The bottom surface of the Mylar film is also preferably coated with a layer of an adhesive. The sheet film covering preferably is contiguous and serves the purpose, among other things, to protect the underlying surface of the pressure-sensing device from contaminants and from electrostatic discharge, as well provide force concentration during use.

Abstract: A fingerprint-sensing device with a sensor array that does not use active switching elements is fabricated on a base. Sensor support integrated circuits, which contain processing and addressing circuitry, are separately fabricated and subsequently mounted on the base, establishing electrical connections with an interconnect structure within the base, and are thus not integrated with the sensor array. The sensor support integrated circuits can be covered by a bezel structure and the sensor array by a covering material. In addition, a connection cable can be provided to connect the sensor array and the sensor support integrated circuits with a power source and to other external devices and to convey signals generated by the sensor array to the external devices.

Abstract: The present invention is directed to a method of sensing pressure in which applied pressure causes a change in the magnetization vector of a magnetoresistive layer within the device and a corresponding change in resistance. The method includes providing a sensing device with a sensor including plurality of layers, the plurality of layers comprising a non magnetic conducting layer disposed between a magnetoresistive layer with non-zero magnetostriction and a ferromagnetic biasing layer. Once provided, the method then includes sensing a resistance in the plurality of layers upon application of pressure to the sensing device, the applied pressure causing the magnetization vector of the magnetoresistive layer to change and thereby result in a change in resistance.

Abstract: The invention provides an apparatus for sensing pressure that comprises a substrate and a sensor formed on the substrate. The sensor is adapted to sense pressure applied thereto and includes a support structure smaller than the substrate to result in a cavity above a portion of the substrate and a magnetoresistive sensor formed over the support structure. The magnetoresistive element provides high sensitivity to pressure while maintaining miniaturized dimensions.

Abstract: The present invention provides a pressure sensing device that includes at least one TMR sensor, and preferably an array of TMR sensors, with each TMR sensor having an insulating spacer layer interposed between a pinned and a free ferromagnetic layer. In an unbiased state, the magnetization vector of each of the ferromagnetic layers is preferably parallel to each other. Upon application of a small voltage, the magnetization vectors remain unchanged. Upon application of stress, the magnetization vector of the free magnetic layer will rotate, thus causing a corresponding and proportionally related change in the resistance of the sensor. This change in resistance can be sensed and used to calculate the stress applied thereto.

Abstract: A modified atomic force microscope (AFM) is used to perform contact resistance and/or current-dependent stiction measurements for conductive thin films at controlled values of applied force. The measurements are preferably performed under conditions approximating the operation of the thin films as electrodes in microswitch array fingerprint sensors. A first, planar thin film is contacted with a second, curved thin film deposited over a round ball having a diameter of a few microns to a few tens of microns. The second film is preferably a coating deposited over the ball and over the arm controlling the ball motion. The coating deposited over the arm provides an electrically conductive path to the contact surface of the ball.

Abstract: The invention provides an apparatus for sensing pressure that comprises a substrate and a sensor formed on the substrate. The sensor is adapted to sense pressure applied thereto and includes a support structure smaller than the substrate to result in a cavity above a portion of the substrate and a magnetoresistive sensor formed over the support structure.

Abstract: The present invention is directed to a method of sensing pressure in which applied pressure causes a change in the magnetization vector of a magnetoresistive layer within the device and a corresponding change in resistance. The method includes providing a sensing device with a sensor including plurality of layers, the plurality of layers comprising a non magnetic conducting layer disposed between a magnetoresistive layer with non-zero magnetostriction and a ferromagnetic biasing layer. Once provided, the method then includes sensing a resistance in the plurality of layers upon application of pressure to the sensing device, the applied pressure causing the magnetization vector of the magnetoresistive layer to change and thereby result in a change in resistance.

Abstract: A modified atomic force microscope (AFM) is used to perform contact resistance and/or current-dependent stiction measurements for conductive thin films at controlled values of applied force. The measurements are preferably performed under conditions approximating the operation of the thin films as electrodes in microswitch array fingerprint sensors. A first, planar thin film is contacted with a second, curved thin film deposited over a round ball having a diameter of a few microns to a few tens of microns. The second film is preferably a coating deposited over the ball and over the arm controlling the ball motion. The coating deposited over the arm provides an electrically conductive path to the contact surface of the ball.

Abstract: An alternate method of designing and manufacturing a semiconductor pressure sensor inherently allows for significantly improved sensitivity, thereby allowing miniaturization of the sensor. As a result, the design lends itself to arranging the pressure sensors using this method in a two dimensional array, and measuring pressure distributions with very high lateral resolution. Furthermore, the design eliminates some of the processing complexities associated with the designs taught in the prior art, specifically those related to processes for manufacturing the plates of the parallel plate capacitor, or the piezoresistive strain elements. The invention allows the manufacture a two dimensional array of pressure sensors with very fine lateral resolution, which provides a much improved means over the prior art of recording fingerprints and the like.

Abstract: A sensor for identifying fingerprints or other skin textures includes an array of cells each including a membrane switch. Each switch includes a fixed lower electrode disposed on a chip substrate, and a flexible membrane disposed over the lower electrode and capable of flexing downward to establish electrical contact between the lower electrode and an upper electrode. The upper electrode can form the membrane itself or a layer of the membrane, or can be attached to other membrane layers. Switches situated underneath skin ridges change state (e.g. are closed) by the applied pressure, while switches underneath skin valleys remain in their quiescent state (e.g. open). Adjacent switch chambers are connected by fluid tunnels which allow the passage of air between the chambers. Each chamber is substantially closed to the exterior of the sensor, such that particles from the environment cannot contaminate the switch contact surface defined between the switch electrodes.

Abstract: A modified atomic force microscope (AFM) is used to perform contact resistance and/or current-dependent stiction measurements for conductive thin films at controlled values of applied force. The measurements are preferably performed under conditions approximating the operation of the thin films as electrodes in microswitch array fingerprint sensors. A first, planar thin film is contacted with a second, curved thin film deposited over a round ball having a diameter of a few microns to a few tens of microns. The second film is preferably a coating deposited over the ball and over the arm controlling the ball motion. The coating deposited over the arm provides an electrically conductive path to the contact surface of the ball.

Abstract: A modified atomic force microscope (AFM) is used to perform contact resistance and/or current-dependent stiction measurements for conductive thin films at controlled values of applied force. The measurements are preferably performed under conditions approximating the operation of the thin films as electrodes in microswitch array fingerprint sensors. A first, planar thin film is contacted with a second, curved thin film deposited over a round ball having a diameter of a few microns to a few tens of microns. The second film is preferably a coating deposited over the ball and over the arm controlling the ball motion. The coating deposited over the arm provides an electrically conductive path to the contact surface of the ball.

Abstract: The present invention provides a pressure based fingerprint image capture device that includes an array of cantilevers or simply suspended bridges, with each pressure based sensor having a cantilever or a simply suspended bridge in contact with a conducting electrode that deforms under the load applied by the localized ridge on the fingerprint, and which provides contact to another conducting electrode thereby closing the electrical circuit, a switch in the simplest form, and providing a “pulse” response from the sensor. In the quiescent state, each cantilever or simply suspended bridge structure contains an upper electrode which forms one part of the switch, while another conducting layer, the lower electrode at the bottom of the well of the individual sensor, forms the other part of the switch.

Abstract: A modified atomic force microscope (AFM) is used to perform contact resistance and/or current-dependent stiction measurements for conductive thin films at controlled values of applied force. The measurements are preferably performed under conditions approximating the operation of the thin films as electrodes in microswitch array fingerprint sensors. A first, planar thin film is contacted with a second, curved thin film deposited over a round ball having a diameter of a few microns to a few tens of microns. The second film is preferably a coating deposited over the ball and over the arm controlling the ball motion. The coating deposited over the arm provides an electrically conductive path to the contact surface of the ball.

Abstract: The present invention provides a pressure sensing device that includes at least one GMR sensor, and preferably an array of GMR sensors, with each GMR sensor having a conducting spacer layer interposed between two ferromagnetic layers. In an unbiased state, the magnetization vector of each of the ferromagnetic layers is preferably parallel to each other. Upon application of a current, however, the magnetization vector of each ferromagnetic layer is changed, preferably to an antiparallel position, in which state the sensor is used to then sense stress applied thereto. Upon application of stress, the magnetization vectors of both free magnetic layers will rotate, thus causing a corresponding and proportionally related change in the resistance of the sensor. This change in resistance can be sensed and used to calculate the stress applied thereto.

Abstract: A fingerprint-sensing device with a sensor array that does not use active switching elements is fabricated on a base. Sensor support integrated circuits, which contain processing and addressing circuitry, are separately fabricated and subsequently mounted on the base, establishing electrical connections with an interconnect structure within the base, and are thus not integrated with the sensor array. The sensor support integrated circuits can be covered by a bezel structure and the sensor array by a covering material. In addition, a connection cable can be provided to connect the sensor array and the sensor support integrated circuits with a power source and to other external devices and to convey signals generated by the sensor array to the external devices.