Capacitive Touch Panel and the Sensing Method Thereof
The invention discloses a capacitive touch panel, comprising: a comparator receiving a sense signal of a sense path and a reference signal of a reference path at a first input and a second input of the comparator, respectively; a transparent electrode coupled to the sense path and the reference path; a variable transfer capacitance connected to the first input or the second input of the comparator; and a control unit connected to an output of the comparator.
1 . A capacitive touch panel, comprising:
a comparator receiving a sense signal of a sense path and a reference signal of a reference path at a first input and a second input of said comparator, respectively;
a transparent electrode coupled to said sense path and said reference path;
a variable transfer capacitance connected to said first input or said second input of said comparator; and
a control unit connected to an output of said comparator.
2 . The capacitive touch panel of claim 1 , wherein said variable transfer capacitance is controlled by a digital command produced by said control unit.
3 . The capacitive touch panel of claim 1 , wherein said output from said comparator is based on inputs of said transparent electrode.
4 . The capacitive touch panel of claim 1 , wherein a first output of said comparator is 1 if said reference signal through said reference path is higher than that of said sense signal through said sense path.
5 . The capacitive touch panel of claim 1 , wherein a second output of said comparator is 0 if said reference signal is smaller than that of said sense signal.
6 . The capacitive touch panel of claim 1 , wherein a noise possibility is transferred to a noise count after performing a sampling process when touching said sense path.
7 . The capacitive touch panel of claim 6 , wherein said noise count is set as a switching threshold value for an identification of said touching, and a circuit sensitivity for said touching can be adjusted when a reference level without touching and said switching threshold value are adjusted.
8 . The capacitive touch panel of claim 1 , further comprising a plurality of comparators to detect sense signals of said sense path at the same time.
9 . A touch-sensing circuit, comprising:
a comparator receiving a sense signal of a sense path and a reference signal of a reference path at a first input and a second input of said comparator, respectively;
a transparent electrode coupled to said sense path and said reference path;
a variable transfer capacitance connected to said first input or said second input of said comparator; and
a control unit connected to an output of said comparator.
10 . The touch-sensing circuit of claim 9 , wherein said output from said comparator is based on inputs of said transparent electrode.
11 . The touch-sensing circuit of claim 9 , wherein a first output of said comparator is 1 if said reference signal through said reference path is higher than that of said sense signal through said sense path, and a second output of said comparator is 0 if said reference signal is smaller than that of said sense signal.
12 . The touch-sensing circuit of claim 9 , wherein a noise possibility is transferred to a noise count after performing a sampling process when touching said sense path, wherein said noise count is set as a switching threshold value for an identification of said touching, and a circuit sensitivity for said touching can be adjusted when a reference level without touching and said switching threshold value are adjusted.
13 . A sensing method for a capacitive touch panel, comprising:
receiving a sense signal of a sense path and a reference signal of a reference path;
setting an intensity of said reference signal lower than that of said sense signal at an initial state;
outputting a relative high voltage level if said reference signal is higher than that of said sense signal;
determining a counting value in a period of time from said sense signal; and
determining an intensity of said sense signal based on said counting value.
14 . The method of claim 13 , wherein said counting value is outputted by a comparator.
15 . The method of claim 14 , wherein an output signal of said comparator is sampled by an internal clock in a control circuit.
16 . The method of claim 14 , wherein a first output of said comparator is 1 if said reference signal through said reference path is higher than that of said sense signal through said sense path.
17 . The method of claim 14 , wherein a second output of said comparator is 0 if said reference signal is smaller than that of said sense signal.
18 . The method of claim 13 , wherein a noise possibility is transferred to a noise count after performing a sampling process.
19 . The method of claim 18 , wherein said noise count is set as a switching threshold value for an identification of a touching signal, and a circuit sensitivity for said touching signal can be adjusted when a reference level without touching and said switching threshold value are adjusted.
20 . The method of claim 13 , further comprising providing a plurality of comparators to detect sense signal of said sense path at the same time.