Touch Position Finding Method and Apparatus
First Claim
1. A method of determining a touch location from a data set output from a touch screen comprising an array of sensing nodes, the data set comprising signal values for each of the sensing nodes, the method comprising:
- a) receiving said data set as input;
b) identifying a touch in the data set, wherein a touch is defined by a subset of the data set made up of a contiguous group of nodes;
c) determining the touch location in each dimension as being at or adjacent the node at which the sum of the signal values assigned to the touch on either side of said node are equal or approximately equal.
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Accused Products
Abstract
In a touch sensor comprising a plurality of sensing nodes, the touch location in each dimension is obtained from the node at which the sum of the signal values assigned to the touch on either side of said node are equal or approximately equal. Each of the sensing nodes is replaced by a plurality of notional sensing nodes distributed around its respective sensing node over a distance corresponding to an internode spacing. Signal values 2, 6, 11, 5 and 2 have been obtained for the distribution of signal across the touch sensor. These signals are notionally split in equal spacings in the range covered by each node, each notional signal being shown with vertical tally sticks. The touch coordinate is then determined by finding the position of the median tally stick. Since there are 26 notional signals, each with a signal value of 1, the position of the median signal is between the 13th and 14th notional signals, as indicated by the thick arrow. This is a numerically simple method for obtaining touch coordinates at higher resolution than the resolution of the nodes ideally suited for implementation on a microcontroller.
77 Citations
12 Claims
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1. A method of determining a touch location from a data set output from a touch screen comprising an array of sensing nodes, the data set comprising signal values for each of the sensing nodes, the method comprising:
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a) receiving said data set as input; b) identifying a touch in the data set, wherein a touch is defined by a subset of the data set made up of a contiguous group of nodes; c) determining the touch location in each dimension as being at or adjacent the node at which the sum of the signal values assigned to the touch on either side of said node are equal or approximately equal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification