TWO-DIMENSIONAL TOUCH PANEL
First Claim
1. A 2D touch-sensitive capacitive position sensor comprising:
- (a) a touch panel having a plurality of sensing elements distributed over its area;
(b) a capacitance measurement circuit connected to the sensing elements and operable repeatedly to acquire sets of capacitance signal values, each set being made up of a capacitance signal value from each of the sensing elements; and
(c) a processor connected to receive the sets of capacitance signal values and operable to process each set to compute and output coordinates of single or multiple touch locations on the touch panel, the processing of each set being performed by;
(i) identifying the sensing element having the largest capacitance signal value;
(ii) defining a region of the touch panel including said sensing element having the largest capacitance signal value and selected ones of its neighbours;
(iii) identifying and defining one or more further sensing elements and regions respectively, wherein each iteration excludes capacitance signal values from consideration if they lie in previously defined regions of the touch panel; and
(iv) outputting data indicating the coordinates of the touch location in each region identified.
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Abstract
A capacitive touch panel is provided capable of detecting multiple simultaneous touches. The touch panel delivers sets of capacitance signal values to a processor which computes the coordinates of single or multiple touch locations on the touch panel. The processing of each set is performed by (i) identifying the sensing element having the largest capacitance signal value; (ii) defining a region around that sensing element; and (iii) repeating the process iteratively, wherein each subsequent identifying step excludes signals that lie in previously defined regions. A multi-touch sensor is thus provided in which the signal processing is based on successive definition of regions or sub-blocks in the touch: panel. The touch location in each region can be determined more accurately by then applying interpolation between the adjacent signal values. This allows for position resolution at a finer scale than that defined by the touch panel'"'"'s electrode patterning.
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Citations
16 Claims
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1. A 2D touch-sensitive capacitive position sensor comprising:
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(a) a touch panel having a plurality of sensing elements distributed over its area; (b) a capacitance measurement circuit connected to the sensing elements and operable repeatedly to acquire sets of capacitance signal values, each set being made up of a capacitance signal value from each of the sensing elements; and (c) a processor connected to receive the sets of capacitance signal values and operable to process each set to compute and output coordinates of single or multiple touch locations on the touch panel, the processing of each set being performed by; (i) identifying the sensing element having the largest capacitance signal value; (ii) defining a region of the touch panel including said sensing element having the largest capacitance signal value and selected ones of its neighbours; (iii) identifying and defining one or more further sensing elements and regions respectively, wherein each iteration excludes capacitance signal values from consideration if they lie in previously defined regions of the touch panel; and (iv) outputting data indicating the coordinates of the touch location in each region identified. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of processing signals from a 2D touch-sensitive capacitive position sensor comprising:
- (a) a touch panel having a plurality of sensing elements distributed over its area;
(b) a capacitance measurement circuit connected to the sensing elements and operable repeatedly to acquire sets of capacitance signal values, each set being made up of a capacitance signal value from each of the sensing elements; and
(c) a 20 processor connected to receive the sets of capacitance signal values and operable toprocess each set to compute and output coordinates of single or multiple touch locations on the touch panel, the method of processing each set comprising; (i) identifying the sensing element having the largest capacitance signal value; (ii) defining a region of the touch panel including said sensing element having the largest capacitance signal value and selected ones of its neighbours; (iii) identifying and defining one or more further sensing elements and regions respectively, wherein each iteration excludes capacitance signal values from consideration if they lie in previously defined regions of the touch panel; and (iv) outputting data indicating the coordinates of the touch location in each region identified. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
- (a) a touch panel having a plurality of sensing elements distributed over its area;
Specification