SYNCHRONOUS TIMED ORTHOGONAL MEASUREMENT PATTERN FOR MULTI-TOUCH SENSING ON A TOUCHPAD
First Claim
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1. A method for detecting the presence of multiple objects on a touchpad, said method comprising the steps of:
- 1) providing a touchpad with two co-planar sets of electrodes arranged as orthogonal arrays, wherein a first set of electrodes act as drive electrodes, and a second set of electrodes act as sense electrodes;
2) simultaneously stimulating all of the drive electrodes using a coded pattern of stimulus signals;
3) receiving data regarding capacitance at each electrode junction;
4) generating raw image data of a surface of the touchpad from the data; and
5) processing the raw image data to thereby extract contact information that is used to generate an image of all objects touching a surface of the touchpad.
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Abstract
A method for detecting multiple objects on a touchpad having a grid of orthogonal electrodes, wherein all drive electrodes are simultaneously stimulated, and then frequency or electrode coding is used to separate each electrode junction and produce a capacitance image of the touchpad surface in a single measurement sequence.
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Citations
9 Claims
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1. A method for detecting the presence of multiple objects on a touchpad, said method comprising the steps of:
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1) providing a touchpad with two co-planar sets of electrodes arranged as orthogonal arrays, wherein a first set of electrodes act as drive electrodes, and a second set of electrodes act as sense electrodes; 2) simultaneously stimulating all of the drive electrodes using a coded pattern of stimulus signals; 3) receiving data regarding capacitance at each electrode junction; 4) generating raw image data of a surface of the touchpad from the data; and 5) processing the raw image data to thereby extract contact information that is used to generate an image of all objects touching a surface of the touchpad. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. The method as defined in claim 9 wherein the step of balancing further comprises the step of reducing the dynamic range of sense signals without reducing the amount of modulation of a contact.
Specification