Touch Sensor
First Claim
1. A device incorporating a capacitive touch sensor, the device comprising:
- a touch panel having on an upper side a touch surface and on a lower side an internal surface, the touch panel being made of a dielectric material;
a set of X electrodes arranged under the touch panel and having a zeroth order branch extending in an x direction; and
a set of Y electrodes arranged under the touch panel and having a zeroth order branch extending in a y direction different from the x direction, such that the zeroth order branches of the X and Y electrodes cross each other at crossing points to form a two-dimensional array of nodes which defines a touch sensitive area on the touch panel, wherein the aspect ratio of the touch sensitive area is equal to or greater than at least one of;
4;
3, 3;
2, 8;
5, 16;
9 and 8;
3,wherein the ratio of the area covered by each of the X electrodes to the area covered by each of the Y electrodes is matched to lie within 20% of the aspect ratio of touch sensitive area, so that the self capacitance of each of the X electrodes and the self capacitance of each of the Y electrodes are at least approximately the same.
2 Assignments
0 Petitions
Accused Products
Abstract
A capacitive touch sensor device comprising set of crossing X and Y electrodes whose crossing points form a two-dimensional array of nodes which define a touch sensitive area. As well as the main electrode spines which cross, referred to as zeroth order electrode branches, the electrodes have higher order branches, some of which interdigitate. By varying the dimensions of the electrode branches, such as width and length, the overall area of the X and Y electrodes can be varied relatively independently of each other. It is therefore possible to produce an electrode pattern in which the self capacitances of the X and Y electrodes have a certain ratio, e.g. unity, and thereby compensate for the aspect ratio of the touch sensitive area, and/or to have a certain absolute value, e.g. in order not to overload a touch-sensor controller to which the sensor is to be connected.
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Citations
18 Claims
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1. A device incorporating a capacitive touch sensor, the device comprising:
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a touch panel having on an upper side a touch surface and on a lower side an internal surface, the touch panel being made of a dielectric material; a set of X electrodes arranged under the touch panel and having a zeroth order branch extending in an x direction; and a set of Y electrodes arranged under the touch panel and having a zeroth order branch extending in a y direction different from the x direction, such that the zeroth order branches of the X and Y electrodes cross each other at crossing points to form a two-dimensional array of nodes which defines a touch sensitive area on the touch panel, wherein the aspect ratio of the touch sensitive area is equal to or greater than at least one of;
4;
3, 3;
2, 8;
5, 16;
9 and 8;
3,wherein the ratio of the area covered by each of the X electrodes to the area covered by each of the Y electrodes is matched to lie within 20% of the aspect ratio of touch sensitive area, so that the self capacitance of each of the X electrodes and the self capacitance of each of the Y electrodes are at least approximately the same. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of manufacturing a device incorporating a capacitive touch sensor, the method comprising:
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providing a touch panel having on an upper side a touch surface and on a lower side an internal surface, the touch panel being made of a dielectric material; fabricating a set of X electrodes arranged under the touch panel and having a zeroth order branch extending in an x direction; and fabricating a set of Y electrodes arranged under the touch panel and having a zeroth order branch extending in a y direction different from the x direction, such that the zeroth order branches of the X and Y electrodes cross each other at crossing points to form a two-dimensional array of nodes which defines a touch sensitive area on the touch panel, wherein the aspect ratio of the touch sensitive area is equal to or greater than at least one of;
4;
3, 3;
2, 8;
5, 16;
9 and 8;
3,wherein the ratio of the area covered by each of the X electrodes to the area covered by each of the Y electrodes is matched to lie within 20% of the aspect ratio of the touch sensitive area, so that the self capacitance of each of the X electrodes and the self capacitance of each of the Y electrodes are at least approximately the same.
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12. A computer automated method for designing an electrode pattern for a capacitive touch sensor, the method comprising:
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selecting an electrode pattern template relating to an electrode pattern comprising; (a) a set of X electrodes having a zeroth order branch extending in an x direction and a plurality of higher order branches; and (b) a set of Y electrodes having a zeroth order branch extending in a y direction different from the x direction, such that the zeroth order branches of the X and Y electrodes cross each other at crossing points to form a two-dimensional array of nodes which defines a touch sensitive area, the set of Y electrodes further comprising a plurality of higher order branches, wherein at least some of the higher order X and Y branches extend alongside one another separated by a gap; generating a specification for the desired electrode pattern which specifies; (a) lateral dimensions in x and y directions for the touch sensitive area; (b) a number of nodes in each of the x and y directions for the touch sensitive area which correspond to the number of Y and X electrodes respectively; and (c) at least one area parameter for the X and Y electrodes; and generating an electrode pattern by varying dimensional parameters within the electrode pattern template affecting at least one of the zeroth order and higher order branches of at least one of the X and Y electrodes in order that the generated electrode pattern meets the specification. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A device incorporating a capacitive touch sensor connected to a touch-sensor controller,
wherein the capacitive touch sensor comprises: -
a touch panel having on an upper side a touch surface and on a lower side an internal surface, the touch panel being made of a dielectric material; a set of X electrodes arranged under the touch panel and having a zeroth order branch extending in an x direction; a set of Y electrodes arranged under the touch panel and having a zeroth order branch extending in a y direction different from the x direction, such that the zeroth order branches of the X and Y electrodes cross each other at crossing points to form a two-dimensional array of nodes which defines a touch sensitive area on the touch panel, wherein the aspect ratio of the touch sensitive area is equal to or greater than at least one of;
4;
3, 3;
2, 8;
5, 16;
9 and 8;
3,wherein the touch-sensor controller comprises; a plurality of X sensor inputs connected to the X electrodes and a plurality of Y sensor inputs connected to the Y electrodes, the X sensor inputs being operable up to a maximum X self capacitance, and the Y sensor inputs being operable up to a maximum Y self capacitance, wherein the area covered by each of the X electrodes and the area covered by each of the Y electrodes are associated with respective X and Y self capacitances which are at or below said maximum X and Y self capacitances of the X and Y sensor inputs.
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Specification