TOUCH SENSING METHOD, TOUCH SENSING CONTROLLER AND TOUCH SENSING DEVICE
A touch sensing method which determines whether or not a touch is generated based on a driving frequency amplitude of a driving signal and a sensing frequency amplitude corresponding to a sensing signal, a touch sensing controller and a touch sensing device having the touch sensing controller are disclosed. A touch sensing controller includes a driving unit, a sensing unit, a control unit and a noise sensing unit. The driving unit provides a plurality of driving electrodes with a plurality of driving signals having different frequencies to each other, respectively. The sensing unit performs a Fast Fourier transform (FFT) processing the sensing signals sensed at the sensing electrodes to determine whether or not a touch is generated based on a variation amount between frequency magnitude of the sensing signal and frequency magnitude of the driving signal. The control unit controls an operation of the driving unit and an operation of the sensing unit. The noise sensing unit senses a surrounding noise component and providing the control unit with a frequency characteristic of the sensed noise component.
1 . A touch sensing method comprising:
providing a plurality of driving electrodes with a plurality of driving signals having different frequencies to each other, respectively;
amplifying a sensing signal sensed through a plurality of sensing electrodes;
performing an analog-to-digital conversion of the amplified sensing signal;
performing a Fast Fourier transform (FFT) processing on the analog-to-digital converted sensing signal to obtain frequency magnitude of the sensing signal; and
determining whether or not a touch is generated based on a variation amount between frequency magnitude of the Fast Fourier transformed sensing signal and frequency magnitude of the driving signal,
wherein the frequency of the driving signal is set so as to avoid a frequency band of a noise component.
2 . The touch sensing method of claim 1 , wherein the driving signals are simultaneously provided to the driving electrodes.
3 . The touch sensing method of claim 1 , wherein a frequency of the driving signal is set by excluding a frequency band of the noise component when a noise component flows during the touch sensing operation.
4 . The touch sensing method of claim 1 , wherein the amplified signal is analog-to-digital converted at a frequency two times faster than the frequency of the driving signal.
5 . The touch sensing method of claim 1 , wherein the sensing signal sensed through the sensing electrodes is band-pass filtered.
6 . A touch sensing controller comprising:
a driving unit providing a plurality of driving electrodes with a plurality of driving signals having different frequencies to each other, respectively;
a sensing unit performing a Fast Fourier transform (FFT) processing the sensing signals sensed at the sensing electrodes to determine whether or not a touch is generated based on a variation amount between frequency magnitude of the sensing signal and frequency magnitude of the driving signal;
a control unit controlling an operation of the driving unit and an operation of the sensing unit; and
a noise sensing unit sensing a surrounding noise component and providing the control unit with a frequency characteristic of the sensed noise component.
7 . The touch sensing controller of claim 6 , wherein the driving unit provides the driving electrodes with the driving signals, respectively.
8 . The touch sensing controller of claim 6 , wherein the sensing unit comprises:
a signal amplifying unit comprising a plurality of signal amplifiers connected to each of the sensing electrodes, amplifying a sensing signal output from each of the sensing electrodes;
an analog-to-digital converting unit comprising a plurality of analog-to-digital converters and digitally converting each of the amplified sensing signals;
a Fast Fourier transform unit comprising a plurality of Fast Fourier transformers, Fast Fourier transforming each of the digitally converted sensing signals; and
a touch determining unit determining whether or not a touch is generated based on a variation amount between frequency magnitudes of the Fast Fourier transformed sensing signal based on frequency magnitude of the driving signal.
9 . The touch sensing controller of claim 8 , wherein the sensing unit further comprises a bandpass filter unit comprising a plurality of band-pass filters,
wherein the bandpass filter unit filters each of the amplified sensing signals to provide the analog-to-digital converting unit with the filtered sensing signals.
10 . The touch sensing controller of claim 6 , wherein the sensing unit comprises:
a multiplexer connected to each of the sensing electrodes, selecting one of the sensing signals output from each of the sensing electrodes;
a signal amplifier amplifying a sensing signal selected by the multiplexer;
an analog-to-digital converting unit digitally converting the amplified sensing signal;
a Fast Fourier transformer performing a Fast Fourier transforming the digitally-converted sensing signal; and
a touch determining unit determining whether or not a touch is generated based on a variation amount between frequency magnitudes of the Fast Fourier transformed sensing signal based on frequency magnitude of the driving signal.
11 . The touch sensing controller of claim 10 , wherein the sensing unit further comprises a band-pass filter,
wherein the band-pass filter filters the amplified sensing signal to provide the analog-to-digital converting unit with the band-pass filtered signal.
12 . The touch sensing controller of claim 8 , wherein the control unit provides the analog-to-digital converting unit with information about the frequency of the driving signal so that the analog-to-digital converting unit converts the driving signal to a frequency faster than the frequency of the driving signal.
13 . The touch sensing controller of claim 12 , wherein the control unit controls the driving unit so that the frequency band of the noise component provided by the noise sensing unit is avoided to generate the driving signal.
14 . A touch sensing apparatus comprising:
a touch panel comprising a plurality of driving electrodes and a plurality of sensing electrodes; and
a touch sensing controller providing a plurality of driving electrodes with a plurality of driving signals having different frequencies to each other, respectively, performing a Fast Fourier transform (FFT) processing on the sensing signals sensed at each of the sensing electrodes to determine whether or not a touch is generated based on a variation amount between frequency magnitude of the sensing signal and frequency magnitude of the driving signal,
wherein the frequency of the driving signal is set so as to avoid a frequency band of noise components around the sensed surroundings.
15 . The touch sensing device of claim 14 , wherein the touch sensing controller comprises:
a driving unit providing the driving electrode with a driving signal; and
a sensing unit receiving a sensing signal from the sensing electrode to obtain frequency magnitude of the sensing signal through a Fast Fourier transform, and determining whether or not a touch is generated based on a variation amount between frequency magnitude of the sensing signal and frequency magnitude of the driving signal.
16 . The touch sensing device of claim 15 , wherein the driving unit simultaneously provides the driving electrodes with the driving signals.
17 . The touch sensing device of claim 15 , wherein the sensing unit comprises:
a signal amplifying unit comprising a plurality of signal amplifiers connected to each of the sensing electrodes, amplifying a sensing signal output from each of the sensing electrodes;
an analog-to-digital converting unit comprising a plurality of analog-to-digital converters and digitally converting each of the amplified sensing signals;
a Fast Fourier transform unit comprising a plurality of Fast Fourier transformers for Fast Fourier transforming each of the digitally converted sensing signals; and
a touch determining unit determining whether or not a touch is generated based on a variation amount between frequency magnitudes of the Fast Fourier transformed sensing signal based on the frequency magnitude of the driving signal.
18 . The touch sensing device of claim 15 , wherein the sensing unit comprises:
a multiplexer connected to each of the sensing electrodes, selecting one of the sensing signals output from each of the sensing electrodes;
a signal amplifier amplifying a sensing signal selected by the multiplexer;
an analog-to-digital converting unit digitally converting the amplified sensing signal;
a Fast Fourier transformer Fast Fourier transforming the digitally-converted sensing signal; and
a touch determining unit determining whether or not a touch is generated based on a variation amount between frequency magnitudes of the Fast Fourier transformed sensing signal based on the frequency magnitude of the driving signal.
19 . The touch sensing device of claim 13 , wherein the touch sensing controller further comprises a control unit provides the analog-to-digital converting unit with information about the frequency of the driving signal so that the analog-to-digital converting unit converts the driving signal to a frequency faster than the frequency of the driving signal.
20 . The touch sensing device of claim 19 , wherein the touch sensing controller further comprises a noise sensing unit sensing a surrounding noise component and providing a frequency characteristic of the sensed noise component to the control unit.
21 . The touch sensing device of claim 20 , wherein the control unit controls the driving unit so as to avoid the frequency band of the noise component provided by the noise sensing unit and generate the driving signal.