A capacitive position sensor has a two-layer electrode structure. Drive electrodes extending in a first direction on a first plane on one side of a substrate. Sense electrodes extend in a second direction on a second plane on the other side of the substrate so that the sense electrodes cross the drive electrodes at a plurality of intersections which collectively form a position sensing array. The sense electrodes are provided with branches extending in the first direction part of the way towards each adjacent sense electrode so that end portions of the branches of adjacent sense electrodes co-extend with each other in the first direction separated by a distance sufficiently small that capacitive coupling to the drive electrode adjacent to the co-extending portion is reduced. Providing sense electrode branches allow a sensor to be made which has a greater extent in the first direction for a given number of sense channels, since the co-extending portions provide an interpolating effect. The number of sense electrode branches per drive electrode can be increased which allows a sensor to be made which has ever greater extent in the first direction without having to increase the number of sense channels.

Capacitive position sensor

A capacitive position sensor for determining the position of an object along first and second directions is described. The sensor comprises a substrate having an arrangement of electrodes mounted on a single surface thereof. The electrodes are arranged so as to define an array of sensing cells arranged in columns and rows to form a sensing area. Each of the sensing cell including a column sensing electrode and a row sensing electrode with the column sensing electrodes of sensing cells in the same column being electrically coupled together and the row sensing electrodes of sensing cells in the same row also being electrically coupled together. Row sensing electrodes of sensing cells at opposing ends of at least one of the rows are connected together by an electrical connection made outside of the sensing area so that there is no requirement for electrical connections to cross within the sensing area, thus providing a capacitive position sensor having a sensing area with electrodes on only one side of a substrate.

Two-dimensional position sensor

Proximity of a body, which may be a user's finger, to an electrode pair (100, 104) is sensed by a charge transfer capacitive measurement approach. The electrode pair (100, 104) thus act as a key (10) that can be arrayed with other electrode pairs to form a keypad, keyboard, linear slider control, or liquid level sensor. In one embodiment of the invention, each key is associated with an alternating voltage source (101) and a pair of electrodes (100, 104) mounted on or within a solid dielectric substrate (103) or panel so as to be separated from each other by a gap. The voltage source (101) is connected to a driven electrode (100), a sampling charge detector (402) is connected to a second, receiving, electrode (104), and the output of the charge detector is, in turn, fed into an amplifier (403) and a charge measurement means (407). Disturbances in coupling between the two electrodes (100, 104) are detected through the solid substrate or panel material (103) when a substance or object approaches or contacts the panel. The receiving electrode (104) is a low-impedance node during the sampling phase of the process, which aids in keeping the sensor from being affected by wiring length or extraneous objects near an output lead.

Capacitive sensor and array

A device for detecting the position of a human finger or other object on a touch-sensitive scrolling pad. Dual independent oscillators may be used to generate two pulse trains at frequencies dependent upon the capacitance of two conductors resulting from the position of the finger on the conductors. The pulses from each oscillator may be counted over a time interval. A ratio-metric measurement may be taken by calculating the ratio of the two counts, and a sum may also be calculated. The ratio of the two counts relates to finger position on the device, and their sum relates to finger pressure upon the device.

Capacitance touch slider

An apparatus and method for converting a capacitance measured on a sensor element to a digital code. The apparatus may include a switching capacitor as a sensor element of a sensing device, and a sigma-delta modulator coupled to the sensor element to convert a capacitance measured on the sensor element to a digital code. The switching capacitor is in a feedback loop of the sigma-delta modulator. The method may include measuring a capacitance on a sensor element of a sensing device using a sigma-delta modulator, and converting the capacitance measured on the sensor element to a digital code.

Capacitance to code converter with sigma-delta modulator

An energy field disturbance sensor comprises an energy field emission means such as a light emitting diode; the emitted field may contain a time-varying component An energy sensing device such as a photodiode receives the field energy to produce a sensing signal related to the intensity of the emitted field and any disturbance therein A second signal complementary to the sensed signal is added in a summing junction to the sensing signal to create a summation signal If the emitted energy field contains a time-varying component, a detection circuit is used to sample the summation signal to convert the summation signal to a proportional detection signal An analog to digital converter converts the detection signal to a digital form Digital processing circuitry modulates the amplitude of the complementary signal or the intensity of the energy field according to the desired mode of operation, and in accordance with the behavior of the digital detection signal and external control signals The circuitry is capable of creating a null condition in the detection signal when the received amplitude of the energy field is such that when added to the complementary signal a cancellation effect occurs; the null condition may be transient or continuous in nature depending on the mode of operation and the nature of the field disturbance

Harald Philipp

Papers

Energy field sensor using summing means