Projective capacitive touchscreen
First Claim
1. A projective capacitive touchscreen, comprising:
- a substrate;
a first plurality of non-linear, non-pad, position sensing electrodes coupled to said substrate, said first plurality of electrodes contained within a plane;
a second plurality of non-linear, non-pad, position sensing electrodes coupled to said substrate, said second plurality of electrodes contained within said plane, said second plurality of electrodes interlaced with said first plurality of electrodes in a non-overlapping pattern;
a first plurality of interconnects for coupling said first plurality of electrodes to a control circuit; and
a second plurality of interconnects for coupling said second plurality of electrodes to said control circuit.
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Accused Products
Abstract
An improved touchscreen utilizing two sets of electrodes that are fabricated in a single plane is provided. The individual electrodes of each set of electrodes are formed from a continuous length of a conductive material. Suitable electrode materials include fine wire and deposited conductive coatings. The overall electrode pattern is such that there is no overlap of electrodes, thus eliminating the need for insulating layers and/or coatings between electrodes. Although a variety of electrode patterns can be used, preferably the pattern is comprised of a plurality of approximately triangularly shaped electrodes, the pattern such that the base of one triangularly shaped electrode is adjacent to the apex of the next triangularly shaped electrode. The preferred triangular shape of an individual electrode can be achieved by forming a continuous loop of the electrode material into the desired shape or by forming a series of teeth of varying height, the envelope of the teeth approximating the desired triangular shape. A touchscreen sensor employing the disclosed sensing electrodes can use any of a variety of readout systems. For example, a frequency-domain readout approach can be used in which the operating frequency is fixed. In this approach a touch capacitance is detected by observing an impedance change at the operating frequency, typically by measuring a corresponding current change. Alternately changes in a RC decay time τ can be measured, for example by observing frequency shifts in a relaxation oscillator. This technique is typically referred to as a time-domain approach. In a third alternate approach, capacitance changes are detected via frequency shifts of LC oscillators. Touch position information is determined from the capacitance changes of the electrodes using any number of different techniques. Preferably prior to calculating position, a subset of electrodes localized around the touch position is determined. Electrode localization reduces the effects of background signals while increasing the efficiency of the position determining algorithm. Once a set of localized electrodes has been determined the touch coordinates are calculated, one coordinate from the distribution of the touch signal within each set of electrodes and the other coordinate from the distribution of the touch signal between the two sets of electrodes.
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Citations
24 Claims
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1. A projective capacitive touchscreen, comprising:
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a substrate;
a first plurality of non-linear, non-pad, position sensing electrodes coupled to said substrate, said first plurality of electrodes contained within a plane;
a second plurality of non-linear, non-pad, position sensing electrodes coupled to said substrate, said second plurality of electrodes contained within said plane, said second plurality of electrodes interlaced with said first plurality of electrodes in a non-overlapping pattern;
a first plurality of interconnects for coupling said first plurality of electrodes to a control circuit; and
a second plurality of interconnects for coupling said second plurality of electrodes to said control circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A projective capacitive touchscreen, comprising:
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a substrate;
a first plurality of non-linear, non-pad, position sensing electrodes coupled to said substrate, said first plurality of electrodes contained within a plane;
a second plurality of non-linear, non-pad, position sensing electrodes coupled to said substrate, said second plurality of electrodes contained within said plane, wherein a portion of said second plurality of electrodes is interlaced with a portion of said first plurality of electrodes in a non-overlapping pattern, said interlaced portion forming a multiple position coordinate determining region, and said non-interlaced portion forming a plurality of simple touch buttons;
a first plurality of interconnects for coupling said first plurality of electrodes to a control circuit; and
a second plurality of interconnects for coupling said second plurality of electrodes to said control circuit.
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Specification