Touch sensor, method of driving the same, and electronic device including the same
A touch sensor includes a touch driver configured to generate a plurality of signals, and a plurality of channels configured to generate the plurality of signals, the plurality of channels including a driving channel configured to transmit a driving signal having a fundamental frequency, a first cancellation channel configured to transmit a first cancellation signal having the fundamental frequency and having an inverse phase of the driving signal, and a second cancellation channel configured to transmit a second cancellation signal having an harmonic frequency of the fundamental frequency and having an inverse phase of an harmonic frequency of the driving signal.
1 . A touch sensor comprising:
a touch driver configured to generate a plurality of signals; and
a plurality of channels configured to transmit the plurality of signals, the plurality of channels including:
a driving channel configured to transmit a driving signal having a fundamental frequency;
a first cancellation channel configured to transmit a first cancellation signal having the fundamental frequency and having an inverse phase of the driving signal; and
a second cancellation channel configured to transmit a second cancellation signal having an harmonic frequency of the fundamental frequency and having an inverse phase of an harmonic frequency of the driving signal.
2 . The touch sensor of claim 1 , wherein the driving signal is a square wave.
3 . The touch sensor of claim 2 , wherein the first cancellation signal is a square wave or a sine wave.
4 . The touch sensor of claim 2 , wherein the second cancellation signal is a square wave or a sine wave.
5 . The touch sensor of claim 1 , wherein the harmonic frequency of the fundamental frequency is an odd multiple of the fundamental frequency.
6 . The touch sensor of claim 1 , wherein the plurality of channels further include:
a guard channel configured to transmit a guard signal having the fundamental frequency and having a same phase as the driving signal.
7 . The touch sensor of claim 6 , wherein the first cancellation signal satisfies an inequality
0.9
*
(
V
_
S
1
*
B
_
S
1
*
NUM
_
S
1
+
V
_
S
2
*
B
_
S
2
*
NUM
_
S
2
)
≤
V
_
S3
*
B
_
S
3
*
NUM
_
S
3
≤
1.1
*
(
V
_
S
1
*
B
_
S
1
*
NUM
_
S
1
+
V
_
S
2
*
B
_
S
2
*
NUM
_
S
2
)
,
wherein V_S 1 is an amplitude of the driving signal, B_S 1 is a burst of the driving signal, NUM_S 1 is a number of the driving signal, V_S 2 is an amplitude of the guard signal, B_S 2 is a burst of the guard signal, NUM_S 2 is a number of the guard signal, V_S 3 is an amplitude of the first cancellation signal, B_S 3 is a burst of the first cancellation signal, and NUM_S 3 is a number of the first cancellation signal.
8 . The touch sensor of claim 7 , wherein the second cancellation channel includes:
a second-first cancellation channel configured to transmit a second-first cancellation signal having a third harmonic frequency, the third harmonic frequency of the second-first cancellation signal being three times the fundamental frequency, and having an inverse phase of a third harmonic frequency of the driving signal; and
a second-second cancellation channel configured to transmit a second-second cancellation signal having a fifth harmonic frequency, the fifth harmonic frequency of the second-second cancellation signal being five times the fundamental frequency, and having an inverse phase of a fifth harmonic frequency of the driving signal.
9 . The touch sensor of claim 8 , wherein the second-first cancellation signal and the second-second cancellation signal satisfy an inequality
V
_
S
3
*
B
_
S
3
*
NUM
_
S
3
>
V
_
S
4
*
B
_
S
4
*
NUM
_
S
4
>
V
_
S
5
*
B
_
S
5
*
NUM
_
S
5
,
wherein V_S 4 is an amplitude of the second-first cancellation signal, B_S 4 is a burst of the second-first cancellation signal, NUM_S 4 is a number of the second-first cancellation signal, V_S 5 is an amplitude of the second-second cancellation signal, B_S 5 is a burst of the second-second cancellation signal, and NUM_S 5 is a number of the second-second cancellation signal.
10 . The touch sensor of claim 6 , wherein the first and second cancellation channels are separated from the driving channel with the guard channel between the first and second cancellation channels and the driving channel.
11 . A method of driving a touch sensor, the method comprising:
generating a driving signal having a fundamental frequency;
generating a first cancellation signal having the fundamental frequency and having an inverse phase of the driving signal;
generating a second cancellation signal having an harmonic frequency of the fundamental frequency and having an inverse phase of an harmonic frequency of the driving signal; and
transmitting the driving signal, the first cancellation signal, and the second cancellation signal.
12 . The method of claim 11 , wherein the driving signal is a square wave.
13 . The method of claim 12 , wherein the first cancellation signal is a square wave or a sine wave.
14 . The method of claim 12 , wherein the second cancellation signal is a square wave or a sine wave.
15 . The method of claim 11 , wherein the harmonic frequency of the fundamental frequency is an odd multiple of the fundamental frequency.
16 . The method of claim 11 , further comprising:
generating a guard signal having the fundamental frequency and having a same phase as the driving signal.
17 . The method of claim 16 , wherein the first cancellation signal satisfies an inequality
0.9
*
(
V
_
S
1
*
B
_
S
1
*
NUM
_
S
1
+
V
_
S
2
*
B
_
S
2
*
NUM
_
S
2
)
≤
V
_
S
3
*
B
_
S
3
*
NUM
_
S
3
≤
1.1
*
(
V
_
S
1
*
B
_
S
1
*
NUM
_
S
1
+
V
_
S
2
*
B
_
S
2
*
NUM
_
S
2
)
,
wherein V_S 1 is an amplitude of the driving signal, B_S 1 is a burst of the driving signal, NUM_S 1 is a number of the driving signal, V_S 2 is an amplitude of the guard signal, B_S 2 is a burst of the guard signal, NUM_S 2 is a number of the guard signal, V_S 3 is an amplitude of the first cancellation signal, B_S 3 is a burst of the first cancellation signal, and NUM_S 3 is a number of the first cancellation signal.
18 . The method of claim 17 , wherein the generating the second cancellation signal includes:
generating a second-first cancellation signal having a third harmonic frequency, the third harmonic frequency of the second-first cancellation signal being three times the fundamental frequency and having an inverse phase of a third harmonic of the driving signal; and
generating a second-second cancellation signal having a fifth harmonic frequency, the fifth harmonic frequency of the second-second cancellation signal being five times the fundamental frequency and having an inverse phase of a fifth harmonic frequency of the driving signal.
19 . The method of claim 18 , wherein the second-first cancellation signal and the second-second cancellation signal satisfy an inequality
V
_
S
3
*
B
_
S
3
*
NUM
_
S
3
>
V
_
S
4
*
B
_
S
4
*
NUM
_
S
4
>
V
_
S
5
*
B
_
S
5
*
NUM
_
S
5
,
wherein V_S 4 is an amplitude of the second-first cancellation signal, B_S 4 is a burst of the second-first cancellation signal, NUM_S 4 is a number of the second-first cancellation signal, V_S 5 is an amplitude of the second-second cancellation signal, B_S 5 is a burst of the second-second cancellation signal, and NUM_S 5 is a number of the second-second cancellation signal.
20 . An electronic device comprising:
a display device including a display panel and a touch sensor on the display panel; and
a processor configured to provide input image data to the display device,
wherein the touch sensor comprises:
a touch driver configured to generate a plurality of signals; and
a plurality of channels configured to transmit the plurality of signals, the plurality of channels including:
a driving channel configured to transmit a driving signal having a fundamental frequency;
a first cancellation channel configured to transmit a first cancellation signal having the fundamental frequency and having an inverse phase of the driving signal; and
a second cancellation channel configured to transmit a second cancellation signal having an harmonic frequency of the fundamental frequency and having an inverse phase of a harmonic frequency of the driving signal.