Synaptics Corporation

Crane Company

Cambridge Integrated Circuits Limited

David Ely

Joseph Kurth Reynolds

Kirk Hargreaves

Julian Haines

Paul Richard Routley

Andrew Nicholas Dames

Bob Lee Mackey

Shawn P Day

Colin Ager

Position sensors to inductively sense a position of a target relative to a number of sensor coils are described. In one embodiment, the target comprises first, second, and third portions positioned on either side of an axis of rotation, such that lateral misalignment between the target and the sensors is compensated between the interaction of the different portions and the sensor coils. In another embodiment, the target comprises first and second portions that are separated along the measurement path such that in a first range of relative positions, the first portion is adjacent to the sensor coils and in a second range of relative positions, the second portion is adjacent to the sensor coils. The first and second portions are asymmetrically arranged relative to the sensor coils such that when each portion is adjacent the same portion of the sensor coils, different signals are induced in the sensor coils.

Position sensing transducer

An object position sensing apparatus including a substrate, a conductive crossbar, and a plurality of resistive elements coupled to the crossbar is described. The resistive elements are coupled to circuitry that can apply an excitation signal, such as a voltage change, to the resistive elements. For each resistive element, an electrical effect responsive to the excitation signal, such as a change in charge flowing to the resistive element, is determined. When an object is proximate to the plurality of resistive elements, the electrical effects change, and a position of the object in one or multiple dimensions can be determined from changes in the electrical effects.

Object position sensing apparatus

Methods, systems and devices are described for detecting a measurable capacitance using sigma-delta measurement techniques. According to various embodiments, a voltage is applied to the measurable capacitance using a first switch. The measurable capacitance is allowed to share charge with a passive network. If the charge on the passive network is past a threshold value, then the charge on the passive network is changed by a known amount for a sufficient number of repetitions until the measurable capacitance can be detected. Such a detection scheme may be readily implemented using conventional components, and can be particularly useful in sensing the position of a finger, stylus or other object with respect to a button, slider, touchpad or other input sensor.

Methods and systems for detecting a capacitance using sigma-delta measurement techniques

Methods, systems and devices are described for detecting a measurable capacitance using charge transfer techniques that can be implemented with many standard microcontrollers, and can share components to reduce device complexity and improve performance. In the various implementations of this embodiment, the passive network used to accumulate charge can be shared between multiple measurable capacitances. Likewise, in various implementations a voltage conditioning circuit configured to provide a variable reference voltage can be shared between multiple measurable capacitances. Finally, in various implementations a guarding electrode configured to guard the measurable capacitances can be shared between multiple measurable capacitances. In each of these cases, sharing components can reduce device complexity and improve performance.

Methods and systems for switched charge transfer capacitance measuring using shared components

Methods, systems and devices are described for detecting a measurable capacitance using charge transfer techniques. According to various embodiments, a charge transfer process is performed for two or more times. During the charge transfer process, a pre-determined voltage is applied to the measurable capacitance, and the measurable capacitance is then allowed to share charge with a filter capacitance through a passive impedance that remains coupled to both the measurable capacitance and to the filter capacitance throughout the charge transfer process. The value of the measurable capacitance can then be determined as a function of a representation of a charge on the filter capacitance and the number of times that the charge transfer process was performed. Such a detection scheme may be readily implemented using conventional components, and can be particularly useful in sensing the position of a finger, stylus or other object with respect to an input sensor.

Methods and systems for detecting a capacitance using switched charge transfer techniques

A security thread for use in a paper-based value document, such as currency or banknote paper, includes a plastic substrate coated with one or more regions of 'soft' magnetic material. A device for verifying both the authenticity and the denomination of the document includes a coil that is driven by an alternating current to thereby provide a uniform magnetic field within a predetermined spatial region. As the document passes in proximity to the drive coil, the applied magnetic field saturates the regions of magnetic material on the security thread. The magnetic regions provide a response magnetic field that, because of the saturation of the magnetic regions, is a non-linear response containing a multiple of frequency components, including a component at the fundamental or drive frequency and various harmonic frequency components. A receive coil senses the response magnetic field. A signal processor connected to the receive coil utilizes the response signals at the fundamental frequency and the low-order harmonic frequencies to determine both the type of magnetic material on the security thread and the denomination of the document from the spatial distribution of the magnetic regions on the security thread.

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Cambridge, United Kingdom

David Ely