Abstract: A capacitive touch sensor providing an automatic switch-off function for an apparatus in which the sensor is incorporated is provided. The sensor comprises a sensing element coupled to a capacitance measurement circuit for measuring the capacitance of the sensing element. A control circuit is operable to determine from the capacitance measurement whether an object is in proximity with the sensor. The determined presence of an object may be used to toggle a function of the apparatus. Furthermore, when it is determined that an object has not been in proximity with the sensor for a predetermined time duration, an output signal for switching off the apparatus is provided. The predetermined time duration may be selected from a number of predefined time durations, or may be programmed using an resistor-capacitor network. Pulses may be applied to the control circuit to override features of the automatic switch-off functionality.

Abstract: A sensor for determining a position for an adjacent object in two dimensions is described. The sensor comprises a substrate with a sensitive area defined by a pattern of electrodes, wherein the pattern of electrodes includes a first group of drive elements interconnected to form a plurality of row electrodes extending along a first direction, a second group of drive elements interconnected to form a plurality of column electrodes extending along a second direction, and a group of sense elements interconnected to form a sense electrode extending along both the first and second directions. The sensor further comprises a controller comprising a drive unit for applying drive signals to the row and column electrodes, and a sense unit for measuring sense signals representing a degree of coupling of the drive signals applied to the row and column electrodes to the sense electrode. Thus a 2D position sensor requiring only a single sense channel is provided.

Abstract: A two-dimensional position sensor is formed by drive electrodes (52) and sense electrodes (62, 64, 66) both extending in the x-direction and interleaved in the y-direction. The sense electrodes comprise several groups, two of which co-extend in the x-direction over each different portions of extent in the x-direction. The drive and sense electrodes are additionally arranged to capacitively couple with each other. In use, drive signals are applied to the drive electrodes and then the resultant sense signals received from the sense electrodes measured. The position of a touch or stylus actuation on the sensor is determined in the x- and y-directions as follows. In the x-direction, the position is determined by an interpolation between sense signals obtained from co-extending pairs of sense electrodes, and in the y-direction by interpolation between sense signals obtained from different sequences of drive signals applied to the drive electrodes.

Abstract: A control panel for controlling a device in response to user indications, the control panel comprising, a position sensing element (60) having a sensing surface, and a position interface circuit (76). The position interface circuit (76) is operable to determine a position of an object (100) on the sensing surface, when the object (100) is applied to the sensing surface of the position sensing element (60). At least one pressure sensing device (54, 66) and the sensing surface of the position sensing element (60) are arranged with the effect that a displacement of the sensing surface with respect to the pressure sensing device in response to the pressure applied by the object is detectable by the pressure sensing device. As such, in one example, the position interface circuit (76) is operable to identify one or more of a plurality of user indicated signals by correlating the position of the object on the sensing surface with a pressure detected by the pressure sensing device.

Abstract: A method of mounting a touch-screen element onto a control panel, and a corresponding assembled unit. In the assembled apparatus, the control panel has the touch-screen element mounted thereto. The touch-screen element comprises a sensing element mounted on a semi-rigid carrier, and first and second clamps for holding opposed sides of the touch-screen element to the panel. At least the second clamps is moveable between open and closed configurations, the open configuration being used during assembly. For assembly, one side of the touch-sensitive element is inserted into the first clamp. The touch-sensitive element is then bent into a curve and pushed down into the second clamp while the second clamp is in its open configuration. Once the touch-sensitive element has been flattened onto the panel and is in the second clamp, the second clamp is closed to complete the assembly.

Abstract: A capacitive touch sensor is provided having sensing path for setting a parameter to a desired value within a range. The sensor has a first mode of operation in which a parameter can be set approximately to a desired value and a second mode in which the value can be refined to the exact amount. In the first mode, the full range of possible values is mapped onto the sensing path and a user touch selects a value within the full range according to its position along the sensing path. In the second mode a finer adjustment is provided for, either by mapping a narrower sub-range of the full range onto the sensing path, or by allowing incremental adjustment of the parameter from the value initially set in the first mode, each incremental unit of adjustment being triggered by the object being displaced through a pre-determined threshold displacement along the sensing path.

Abstract: A capacitive position sensor comprising a preferably annular sensing path, the sensing path having one or more virtual buttons designated along its length. The sensing path has a plurality of terminals connected to it to subdivide it into a plurality of sections, each terminal providing a sensing channel for a signal indicative of capacitance. The sensing channels provide the signals to a processor, preferably a microcontroller, that is operable to distinguish between a user making a touch to actuate one of the virtual buttons, and a touch to perform a scrolling function. To be determined as a scroll, it is required that there is a succession of detects which span over at least a threshold distance, for example an angular or linear distance. To be determined as a touch, it is required that there is a succession of detects that all lie within one of the pre-assigned virtual button positions.

Abstract: A two-dimensional position sensor comprising a substrate with a sensitive area defined by a pattern of electrodes including electrodes for determining x-position and electrodes for determining y-position. The x-electrodes and y-electrodes generally extend in the x-direction and are interleaved in the y-direction. The x-electrodes comprise at least first, second and third groups of elements shaped such that adjacent ones of the elements of the different x-electrode groups co-extend in the x-direction so that the x-electrodes provide ratiometric capacitive signals, thereby providing quasi-continuous x-position sensing across the sensitive area. In addition, the y-electrodes may be resistively connected or arranged in ratiometric pairs to provide quasi-continuous y-position sensing. Alternatively, the x-electrode groups may be interdigitated to form pairs of x-adjacent blocks of differing area to provide stepwise x-position sensing in combination with stepwise y-position sensing provided by the y-electrodes.

Abstract: Apparatus and methods are described for selecting which of a plurality of simultaneously activated keys in a keyboard based on capacitive sensors is a key intended for selection by a user. In embodiments of the invention keys are preferentially selected as the user intended key based on their positions within the keyboard. Thus a key which is frequently wrongly activated when a user selects another key, e.g. because the key is adjacent the intended key and the user normally passes his finger over it while approaching the desired key, can be suppressed relative to the desired key based on their relative positions. For example, keys may be associated with predefined rankings according to their position within the keyboard and in use keys are preferentially select according to their rankings. Alternatively, signals from the keys may be scaled by weighting factors associated with their positions and a key selected according to the weighted signals.

Abstract: A touch sensitive control panel is described. The control panel comprises a sensor surface in which a plurality of sensor areas are arranged and a circuit board offset from the sensor surface. The circuit board has an electrical contact associated with each of the sensor areas. The electrical contacts are connected to capacitance measurement circuitry. The control panel further comprises a guide block having a first side facing the sensor surface, a second side facing the circuit board and a plurality of channels extending from the first side to the second side. A plurality of resilient electrical conductors pass through the channels to connect between the sensor areas and the electrical contacts on the circuit board, such that the capacitance measurement circuitry is coupled to the sensor areas.

Abstract: A touch-sensitive sensor comprises a control circuit board and a sensor substrate which are fixed to a cover panel. Electrical connection terminals on the sensor substrate are adjacent an edge of the circuit board. To establish electrical connections between the sensor substrate and control circuitry on the circuit board, sprung electrical connectors are provided. These are mounted on the side of the circuit board opposite the side which is fixed to the cover panel. This allows the circuit board to be fixed flat against the control panel. The sprung electrical connectors are configured to extend over the edge of the control circuit board and are bent towards the control panel so that they resiliently connect with the connection terminals of the sensor substrate. This allows electrical connections to be established automatically as the sensor substrate is put in place during assembly. The sensor may be based on either capacitance or resistance measurements.

Abstract: A capacitive two-dimensional (2D) touch panel has three sets of interleaved electrodes. A first set of electrodes is spaced apart along the y-direction and these are galvanically connected to each other by a resistive strip connected at either end to a connection line. A second set of electrodes is also arrayed along the y-direction and these are galvanically connected to each other via a notionally non-resistive first connection. A third set of electrodes is also arrayed along the y-direction and these are galvanically connected to each other via a notionally non-resistive second connection. The second and third sets of electrodes are interleaved without galvanic cross-conduction to provide a gradient along the x-direction to resolve touch position in the x-direction. The first set of electrodes resolves touch position along the y-direction. Passive or active capacitive sensing techniques may be used to acquire the position information from the 2D touch panel.

Abstract: A capacitive touch sensitive position sensor is provided which has a substrate defining a touch sensitive platform. First and second resistive bus-bars arranged spaced apart on the substrate. A conductive sensing area is formed between the bus bars and is constructed with first and second conductive elements connected to the first and second resistive bus-bars respectively, and spaced apart from each other by non-conducting gaps, so that currents induced in the conductive sensing area flow towards the bus-bars, but are prevented from flowing in a direction parallel to the bus-bars. This design removes pin-cushion distortion and enhances linearization of the output signals. Because the sensing region is not galvanically coupled from one bus bar to the other, the voltage gradients remain uniform and undistorted. Capacitive coupling from one side to the other does not produce a distortion component provided that the capacitance is allowed to fully charge and discharge across all locations in the sensing region.

Abstract: A control panel having a touch sensitive position sensor and at least one mechanical switch located within a sensitive area of the position sensor is provided. The position sensor comprises a capacitive position sensing element coupled to position sensing circuitry operable to determine the position of a capacitive load, such as a finger, positioned adjacent to the sensitive area of the position sensing element. The mechanical switch has an open state and a closed state and is arranged such that a contact of the switch is selectively electrically coupled to or decoupled from the position sensing element depending on whether the switch is in the open or closed state. A compact and robust control panel can thus be provided in which the presence of the mechanical switch within the sensitive area of the position sensor does not significantly effect its sensitivity.

Abstract: When an array of proximity sensors is used as a keyboard, it can provide an ambiguous output if a user's finger overlaps several keys or if liquid is spilled on the keyboard. This ambiguity is reduced by an iterative method that repeatedly measures a detected signal strength associated with each key, compares all the measured signal strengths to find a maximum, determines that the key having the maximum signal strength is the unique user-selected key and then suppresses or ignores signals from all other keys as long as the signal from the selected key remains above some nominal threshold value.

Abstract: The invention relates to an energy saving headset 100. The headset 100 comprises a power management unit 150 that is operable to reduce the power consumption of the headset 100 when a user 110 is not present. The power management unit 150 uses capacitive sensing to detect the presence of the user 110. Capacitive sensing is advantageous since it provides a flexible and reliable sensor that can accurately detect the presence or absence of a user 110 either by detecting user proximity or user contact. Moreover, in various embodiments, the sensitivity of a capacitive sensor may be adjusted to account for user movement or changes in environmental conditions, such as, for example, the presence of water, or sweat, on the headset 100 to further improve sensing reliability. The invention further relates to headsets using user presence signals based on capacitive sensing to control other functions of the headset or to control external devices to which the headset is connected, either wirelessly or by wires.

Abstract: The invention relates to an energy saving headset that comprises a power management unit operable to reduce the power consumption of the headset when a user is not present. The power management unit uses capacitive sensing to detect the presence of the user. Capacitive sensing is advantageous since it provides a flexible and reliable sensor that can accurately detect the presence or absence of a user either by detecting user proximity or user contact. Moreover, in various embodiments, the sensitivity of a capacitive sensor may be adjusted to account for user movement or changes in environmental conditions, such as, for example, the presence of water, or sweat, on the headset to further improve sensing reliability. The invention further relates to headsets using user presence signals based on capacitive sensing to control other functions of the headset or to control external devices to which the headset is connected, either wirelessly or by wires.

Abstract: A capacitive sensor for determining the presence of an object, such as a user's finger or a stylus, is provided. The sensor comprises a substrate, for example made of transparent plastics material, such as PET, on which electrodes are deposited. A resistive drive electrode for example formed of transparent ITO, is arranged on one side of the substrate and a resistive sense electrode, which again may be of transparent ITO, is arranged on the other side of the substrate. Thus an overall transparent sensor may be provided. A shorting connection is also provided which is configured to connect between two locations on one of the electrodes. The electrodes are connected to respective drive and sense channels. By providing the shorting connection between two locations on one or other (or both) of the electrodes, a lower resistance connection is provided between other locations on the electrode and the corresponding drive or sense channel.