US Patent No. 9,310,952

CAPACITIVE TOUCH SYSTEM USING BOTH SELF AND MUTUAL CAPACITANCE


Patent No. 9,310,952
Issue Date April 12, 2016
Title Capacitive Touch System Using Both Self And Mutual Capacitance
Inventorship Jerry Hanauer, Germantown, WI (US)
Assignee MICROCHIP TECHNOLOGY INCORPORATED, Chandler, AZ (US)

Claim of US Patent No. 9,310,952

1. A method for determining multiple touch events in a multi-touch sensor system having a touch sensor including a plurality
of nodes defined by a plurality of first electrodes arranged in a first layer and second electrodes arranged in a second layer,
the method comprising:
performing self capacitance measurements for at least two of the plurality of second electrodes using a capacitance detector;
detecting one or more touch events as a result of the performed self capacitance measurements;
performing a plurality of mutual capacitance measurements for only a subset of the nodes, wherein the subset is fewer than
all of the nodes and includes at least the nodes corresponding to the touch events and wherein a mutual capacitance measurement
is performed between first and second electrodes, wherein a pulse drive circuit is connected with one of said first electrodes
and the capacitance detector is connected with one of said second electrodes and wherein the pulse drive circuit is synchronized
with the capacitance detector, wherein a mutual capacitance measurement is based on charging and/or discharging of a measured
capacitance and the pulse drive circuit is synchronized to influence the charging and/or discharging of the measured capacitance;
and

detecting two or more touch events as a result of the plurality of mutual capacitance measurements.