Abstract: A number of position sensors inductively sense a target's position relative to a number of sensor coils. The target is magnetically coupled with first and second coils so that signals are generated that depend on the relative position of the target and the first and second coils. Substantially all of the target overlaps with loops of the first coil and so that when a first end of the target is adjacent a first loop of the first coil, a second end of the target is adjacent a second loop of the first coil that has an opposite winding direction to that of the first loop. The second coil is arranged relative to the target such that the magnetic coupling between the second coil and the first end of the target is opposite to the magnetic coupling between the second coil and the second end of the target.

Abstract: A number of position sensors are disclosed. The position sensors are arranged to inductively sense the position of a target relative to a number of sensor coils. The target is arranged to magnetically couple with first and second coils so that signals are generated that depend on the relative position of the target and the first and second coils. The target extends along the measurement path and is inclined relative to the measurement path so that substantially all of the target overlaps with loops of the first coil and so that when a first end of the target is adjacent a first loop of the first coil, a second end of the target is adjacent a second loop of the first coil that has an opposite winding direction to that of the first loop. The second coil is arranged relative to the target such that the magnetic coupling between the second coil and the first end of the target is opposite to the magnetic coupling between the second coil and the second end of the target.

Abstract: A transducer for a position sensor includes a single laminate sensor board carrying a plurality of windings formed by conductors on one or more layers of the sensor board. The windings are arrayed over a first area of the sensor board. Detection circuitry is mounted on another layer of the sensor board over a second area of the circuit board and electrically coupled to the windings. The detection circuitry has a first mode of operation in which signals inductively coupled to or from windings are detected and a second mode of operation in which signals capacitively coupled to or from said windings are detected. The windings and detection circuitry are arranged on the sensor board so that said first and second areas oppose each other. A position sensor incorporates the transducer.

Abstract: A transducer has a magnetic field concentrating member a first coil to couple with a first portion of the magnetic field concentrating member positioned adjacent the first coil and a second coil to couple with a second portion of the magnetic field concentrating member positioned adjacent the second coil, the second portion being spaced along the magnetic field concentrating member from the first portion. The transducer comprises a resonator having a coil wound around a portion of said magnetic field concentrating member which is located between said first and second portions. The transducer is arranged so that the electromagnetic coupling between the resonator and at least one of the first and second coils varies as a function of the relative position between the elongate field concentrating member and that coil. In this way, separate processing electronics can process the signals obtained from the transducer to determine the desired position information.

Abstract: A transducer is described for use in a position sensor. The transducer has a magnetic field concentrating member, such as an elongate ferrite rod, a first coil operable, in use, to couple with a first portion of the magnetic field concentrating member positioned adjacent the first coil and a second coil operable, in use, to couple with a second portion of the magnetic field concentrating member positioned adjacent the second coil, the second portion being spaced along the magnetic field concentrating member from the first portion. The transducer also comprises a resonator having a coil wound around a portion of said magnetic field concentrating member which is located between said first and second portions. The transducer is arranged so that, during use, the electromagnetic coupling between the resonator and at least one of the first and second coils varies as a function of the relative position between the elongate field concentrating member and that coil.

Abstract: An X-Y digitizer system is described for embedding within a host device, such as a tablet PC, a mobile telephone, a personal digital assistant or the like. The digitizer is configurable so that it can detect and track the position of different types of position indicator. The digitizer also includes novel digitizer windings and novel excitation circuitry for energizing the windings.

Abstract: An x-y digitising system is described which operates with a resonant stylus. The x-y digitising system includes an excitation winding for energising the resonant stylus and a number of sensor windings for receiving a signal re-radiated by the resonant stylus when energised. At least one of the excitation winding and the sensor winding is arranged to have its effective magnetic axis non-othogonal to the working area of the x-y digitising system. With this arrangement, improved energy transfer between the x-y digitising system and the resonant stylus can be achieved and/or improved position measurement accuracy can be obtained.

Abstract: A low cost x-y digitising system is described for use in consumer electronic devices, such as portable digital assistants, mobile telephones, web browsers and the like. The digitiser includes a resonant stylus, an excitation winding for energising the resonant stylus and a set of sensor windings for sensing the signal generated by the stylus, from which the x-y position of the stylus is determined. A novel stylus design is described together with novel digitiser windings and novel excitation and processing circuitry.