CN105045426B - A kind of touch-screen anti-noise method and device - Google Patents
A kind of touch-screen anti-noise method and device Download PDFInfo
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Abstract
The present invention proposes the touch screen control device of a kind of touch screen data processing method for suppressing noise and application this method, and this method comprises the following steps：(1) analog signal of touch-screen is received, the analog signal of touch-screen is sampled to obtain data signal；(2) reference value according to corresponding to sampled value calculates the sampled point；(3) deviation of sampled value and corresponding reference value is compared, and by the deviation compared with predetermined threshold value；(4) if deviation is less than threshold value, retain the sampled value, if deviation is more than threshold value, abandon the sampled value, and the sampled value is replaced with the corresponding reference value being calculated；(5) data that step (4) obtains are calculated into touch location for touch information processing.This method can effective suppression common mode noise, improve touch location detection precision.Relative to existing noise cancellation method, there is the advantages of following prominent：Computational methods are simple, and the hardware resource occupancy when touch chip is realized is small, and processing speed is fast, not by scanning signal effect length, can complete the calculating of random length signal.
Description
Technical field
The present invention relates to touch-screen field, more particularly to one kind to be used for antimierophonic touch screen data processing method and touch
Shield control device.
Background technology
Touch-screen is widely used in a portable device, such as mobile phone, tablet personal computer etc..Touch-screen control dress
Put at work, easily disturbed by various noise sources, typical noise is included from charging equipment or display device
Common-mode noise.In touch screen data processing system, common-mode noise is to influence a key factor of systematic function.With charging
The miniaturization and lighting of equipment, its noise jamming are also increasingly severe.Stronger common-mode noise, system can be significantly affected to touching
The response speed and precision of control are touched, position can be caused to report by mistake when serious so that touch-control fails, and has a strong impact on the normal of touch-screen
Work.
As shown in figure 1, in a typical mutual capacitance touchscreens data handling system, touch screen control circuit generally wraps
Include such as lower unit：Driving circuit, touch screen induction circuit, analog/digital conversion unit (ADC), clock module and
Control unit etc..Control unit monitoring in real time is by analog/digital conversion unit (ADC, Analog-to-Digital
Converter the signal (such as capacitance signal, being resistance signal in resistive touch screen)) collected, and be converted into numeral
The original sampling data information of signal form storage, and human body is converted raw data into by processing and touches position on the touchscreen
The information put simultaneously reports system host.The hardware of the control circuit is realized and can realized by IC chip.
When applying a sine or cosine sweep signal is applied to the driving layer of touch panel sensor as excitation, touching
The inductive layer of screen is collected into induced signal, and sends touch screen data handling system to and handled, and passes through AD conversion unit
ADC completes sampling and kept, and obtains the sine or cosine-modulation signal that are advantageous to handle or transmit by amplitude modulation(PAM), such as
Shown in Fig. 2 a.The signal is demodulated, it is possible to touch information to be detected is restored, and for the calculating of touch location.When
No longer it is single sinusoidal or cosine signal in the signal that the inductive layer of touch-screen obtains during by common mold noise interference, but one
Section contains the sampled signal of shake, as shown in Figure 2 b, can not accurate reproduction touch letter to be detected after the signal is demodulated
Breath.
Existing noise cancellation scheme handles coordinate data including the digital filter for setting hardware circuit to realize, it is filtered
Ripple principle is traditional weighted average, takes middle value-based algorithm, takes arithmetic mean value-based algorithm etc., by simple digital filtering not
Can preferably interference caused by suppression common mode noise.In addition, when Chinese publication CN1503118A also proposed a kind of utilization
Clock circuit receives data in the method for reducing noise to control, and this method cost of implementation is high, complicated.
The content of the invention
The purpose of the present invention is the drawbacks described above for prior art, there is provided a kind of to be capable of the tactile of effective suppression common mode noise
The touch screen control device of screen data processing method and application this method is touched, it can eliminate or effectively reduce common-mode noise to touching
Touch the influence of screen position detection.
The present invention proposes a kind of touch screen data processing method for suppressing noise, and it comprises the following steps：
(1) apply a sinusoidal or cosine drive signal to touch-screen, the analog signal of touch-screen is received, to the mould of touch-screen
Intend signal to be sampled to obtain data signal；
(2) reference value according to corresponding to sampled value calculates the sampled point；
(3) deviation of sampled value and corresponding reference value is compared, and by the deviation compared with predetermined threshold value；
(4) if deviation is less than threshold value, retain the sampled value, if deviation is more than threshold value, abandon the sampled value, and
The sampled value is replaced with the corresponding reference value being calculated；
(5) data that step (4) obtains are calculated into touch location for touch information processing.
The present invention proposes a kind of touch screen control device using above-mentioned data processing method, and it includes touch-screen, mould
Plan/digital conversion unit (ADC) and a control unit, analog/digital conversion unit (ADC) receive the simulation letter of touch-screen
Number and be converted to data signal, control unit is connected with analog/digital conversion unit (ADC) and is used to touch by the data signal
Information processing, touch location is calculated.
Touch screen data processing method proposed by the present invention and touch screen control device, effectively suppression common mode it can make an uproar
Sound, relative to existing noise cancellation method, there is the advantages of following prominent, computational methods are simple, when touch chip is realized
Hardware resource take it is small, processing speed is fast, not by scanning signal effect length, can complete the calculating of random length signal.
Brief description of the drawings
Fig. 1 is the canonical schema of existing touch screen data processing system.
Fig. 2 is not by the waveform comparison schematic diagram of noise jamming and the touch-screen scanning signal by noise jamming.Wherein
Fig. 2 a are not by the touch-screen scanning signal schematic diagram of noise jamming, and Fig. 2 b are shown by the touch-screen scanning signal of noise jamming
It is intended to.
Fig. 3 is the schematic flow sheet of the touch screen data processing method proposed by the present invention for effectively suppressing noise.
Fig. 4 is that the signal waveform schematic diagram after noise is eliminated using method proposed by the present invention.
Embodiment
By specific embodiment, the present invention is described in detail below in conjunction with the accompanying drawings.
As shown in figure 3, touch screen data processing method proposed by the present invention comprises the following steps, below to each step
Realization is described in detail；
(1) apply a sinusoidal or cosine drive signal to touch-screen, the analog signal of touch-screen is received, to the mould of touch-screen
Intend signal to be sampled；
In a touch screen data processing system, excitation is used as by the use of one group of sine by amplitude modulation(PAM) or cosine signal
The driving layer of touch panel sensor is applied to, amplitude modulation(PAM) can be realized on the touchscreen, be sensed in the inductive layer of touch-screen
Signal, the induced signal of the analog form is the signal comprising touch information, can be capacitance or resistance value, be somebody's turn to do
Induced signal is received by touch screen data processing system and carries out analog/digital conversion sampling.Such as in a mutual capacitance touch
In sensing equipment, touch chip is transmitted drive signal to the driving layer of touch-screen by driving circuit, and by touching
Touch screen sensor circuit and receive the induced signal from touch-screen；
(2) reference value according to corresponding to sampled value calculates the sampled point；
(3) deviation of sampled value and corresponding reference value is compared, and by the deviation compared with predetermined threshold value Th；
(4) if deviation is less than threshold value Th, retain the sampled value, if deviation is more than threshold value Th, abandon the sampling
Value, and replace the sampled value with the corresponding reference value being calculated；
(5) data that step (4) obtains are calculated into touch location for touch information processing.
The Computing Principle of the reference value in step (2) is described in detail below.
Under no touch state, sample to obtain by the AD conversion unit ADC in touch screen data handling system one group
Sine amplitude sample signal is asin ω t0+ C, asin ω t1+ C ..., asin ω tn+ C ..., n is natural number, n ε [0 ,+∞], tn
For sampling instant.
Wherein a is the amplitude of sine wave, and C is the DC maladjustment value that AD conversion unit ADC is introduced.Due to analog-to-digital conversion list
The sampling time interval of first ADC each sampled point is equal, therefore to 2 points of arbitrary neighborhood, ψ=ω tn+1-ωtnFor definite value, and
, should and its value is determined by the AD conversion unit ADC sampling clocks set, therefore in a specific touch screen control system
It is worth for preset value known to system.Therefore any three adjacent sampled points can be expressed as below：
χ [n-1]=asin (ω tn-ψ)+C (1)
χ [n]=asin (ω tn)+C (2)
χ [n+1]=asin (ω tn+ψ)+C (3)
By formula (1)-(3), it can be deduced that：
χ [n+1]=2 χ [n] cos ψ-χ [n-1]+2C (1-cos ψ) (4)
In formula (4), parameter C is the DC maladjustment value that AD conversion unit ADC is determined, parameter C can be in touch-screen control
In the volume production test of molding group, obtained by ADC performance tests.Test first in normal state, ADC exports the ripple of sine wave
Peak, trough, then average and obtain DC maladjustment value C, and write in the flash memory (flash) of touch chip.
Cos ψ are the cosine values of neighbouring sample point phase difference, and in touch screen control device, ψ values are also by AD conversion unit
ADC sampling period T determinations, ψ=ω tn+1-ωtn=2 π fT, wherein f are the frequencies for scanning sine wave signal.As can be seen here,
In the case of known to AD conversion unit ADC DC maladjustment value and adjacent 2 phase differences, as long as obtaining arbitrary neighborhood two
Point reference value χ [n-1], χ [n], it is possible to the reference value of adjacent thirdly χ [n+1] is calculated by formula (4).As long as obtain
The first two initial reference value χ [0] of sequence, χ [1], then it can go out the reference of all sampled points by recurrence formula (4) recurrence calculation
Value χ [n], initial reference value χ [0], χ [1] can be obtained and stored in advance.It can thus be concluded that to all referring to being worth and form a standard
Reference value sine wave signal.
Initial reference value χ [0], χ [1] can be obtained in advance by the sweep test in normal mode of operation, obtain each sense
Answer the first two initial samples data of passage and as corresponding to reference value and store into the flash memory flash of touch chip, such as
Fruit touch chip has multiple working frequencies, it should collects two initial reference values for each frequency.
The calculating of reference value can be by setting reference value computing unit to realize in touch chip.Under normal mode of operation,
Before each touch detection, parameter initialization configuration is carried out to the module by chip firmware.Need to protect in initial configuration
The parameter being stored in touch chip flash memory has：DC maladjustment value C and two primary standard reference value χ [0], χ [1], neighbouring sample
Point phase difference cosine value cos ψ, and for departure ratio compared with threshold value Th.Reference value computing module is according to initial configuration
Parameter and formula (4), on the basis of ADC samples to obtain each sampled data, are calculated the reference value of this sampling.
As can be seen here, it is only necessary to prestore the reference data of two initial samples points, touch chip can is by formula
(4) reference data of all sampled points is calculated, this method, can be with complete not by the sine or cosine wave effect length of Scanning Detction
Into the calculating of random length reference value, it can realize that the noise in time domain eliminates with the cost of very little.In addition, the algorithm of reference value
It is simple and quick, the hardware resource of the required occupancy also very little in touch chip.
When the interference of no common-mode noise, sampled signal values fluctuation range is smaller compared to reference value caused by touch,
It is in typical case the deviation no more than 10%；And when being disturbed by common-mode noise, variable quantity meeting caused by common-mode noise
It is larger, under extreme case, the 100% or higher of reference value may be reached.
The implementation of step (3) needs to preset a threshold value Th, and threshold value Th scope may be set in reference to sinusoidal or cosine
The 20%~50% of ripple signal amplitude.It is inclined when ADC sampled data values and reference value when AD conversion unit ADC is sampled every time
During from less than threshold value Th, illustrate that no noise or noise are smaller, then the sampled value is set to effective and retained；When discovery ADC is adopted
When deviation of the sample data value than reference value exceedes threshold value Th, illustrate that the sampled data is included compared with very noisy, abandon the sampled data,
And the reference Value Data based on two obtained neighbouring sample points calculates the reference value using formula (4), with result of calculation generation
For former sampled value, obtained data are finally subjected to amplitude demodulation and handled for touch information, touch location is calculated.This
In the case of kind, the deviation of noise introducing is much smaller than using the introduced calculating deviation of the reference value being calculated, so as to realize
Weaken the purpose of noise, effectively eliminate and disturbed caused by common-mode noise.
Specific threshold value Th selection in actual design, can consider the precision of touch screen data processing system and make an uproar
Voice and sentiment condition etc. is adjusted, and threshold value Th chooses too small, it is possible to can cause the erroneous judgement touched with noise, threshold value Th chose
Greatly, it is possible to reduce the anti-noise ability of system.
As shown in figure 4, touch screen data processing method proposed by the present invention can effective suppression common mode noise, by processing
Signal waveform and Fig. 2 b shown in the waveform comparison by noise jamming, effectively eliminate noise.
Under some limiting cases, when noise causes greatly very much most sampled values to have very large deviation, these samplings
The reference value being calculated will be replaced by, now touch screen data processing system will not normally report touch location, but
It is the phenomenon that can effectively prevent from disorderly reporting touch location caused by very noisy, avoids touch-control caused by the wrong report of position from failing, so as to
Prevent that the work of touch-screen applications equipment is not normal.
Claims (4)
1. a kind of touch screen data processing method for being used to suppress noise, it comprises the following steps：
(1) apply a sinusoidal or cosine drive signal to touch-screen, receive the analog signal of touch-screen, the simulation letter to touch-screen
Number sampled to obtain data signal；
(2) reference value according to corresponding to sampled value calculates the sampled point；The reference value is calculated by below equation：
χ [n+1]=2 χ [n] cos ψ-χ [n-1]+2C (1-cos ψ)；
Wherein reference value χ [0], χ [1] are initial samples value, and C is the DC maladjustment value that analog/digital signal conversion is brought, ψ=2
π fT, f are the frequencies of scanning signal, and T is the sampling period, and n is sampling instant；
(3) deviation of sampled value and corresponding reference value is compared, and by the deviation compared with predetermined threshold value Th；
(4) if deviation is less than threshold value Th, retain the sampled value, if deviation is more than threshold value Th, abandon the sampled value, and
The sampled value is replaced with the corresponding reference value being calculated；
(5) data that step (4) obtains are calculated into touch location for touch information processing.
2. touch screen data processing method as claimed in claim 1, the analog signal of the touch-screen is touch screen induction layer
Induced signal.
3. a kind of touch screen control device using any one of the claim 1-2 data processing methods, it include touch-screen,
Analog/digital conversion unit (ADC) and a control unit, analog/digital conversion unit (ADC) receive the simulation of touch-screen
Signal is simultaneously converted to data signal, and control unit is connected with analog/digital conversion unit (ADC) and is used to touch by the data signal
Information processing is touched, touch location, χ [0], χ [1], C, ψ is calculated, Th is pre-stored within the memory cell of the device；Its
Middle reference value χ [0], χ [1] are initial samples value, and C is the DC maladjustment value that analog/digital signal conversion is brought, ψ=2 π fT, f
It is the frequency of scanning signal, T is the sampling period, and n is sampling instant, and Th is threshold value.
4. touch screen control device as claimed in claim 3, including a reference value computing unit, for calculating the reference
Value.
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| CN107102766B (en) * | 2016-02-19 | 2020-07-31 | 禾瑞亚科技股份有限公司 | Method, device and system for reducing interference of driving signal on touch liquid crystal screen |
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| KR102593262B1 (en) * | 2016-11-02 | 2023-10-26 | 삼성전자주식회사 | Touch sensor controller |
| US10585529B2 (en) | 2016-11-04 | 2020-03-10 | Microsoft Technology Licensing, Llc | Selecting correlation reference based on noise estimation |
| CN106610756B (en) * | 2016-11-30 | 2019-07-26 | 北京集创北方科技股份有限公司 | Method of toch control and touch control device |
| US10283135B2 (en) | 2016-12-22 | 2019-05-07 | Microsoft Technology Licensing, Llc | Touchscreen tapping noise suppression |
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| CN110753901A (en) * | 2017-11-02 | 2020-02-04 | 深圳市柔宇科技有限公司 | Signal processing method of touch device, touch device and storage medium |
| WO2019127213A1 (en) * | 2017-12-28 | 2019-07-04 | 深圳市汇顶科技股份有限公司 | Noise eliminating circuit and touch device |
| CN108710453B (en) | 2018-06-26 | 2020-09-11 | 北京集创北方科技股份有限公司 | Touch panel, electronic equipment and information processing method |
| CN110658935B (en) * | 2018-06-29 | 2022-02-22 | 京东方科技集团股份有限公司 | Data detection method and device, storage medium and touch device |
| CN109324711B (en) * | 2018-08-17 | 2022-06-21 | 北京集创北方科技股份有限公司 | Data processing method and device |
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| CN109582176B (en) * | 2018-11-30 | 2021-12-24 | 北京集创北方科技股份有限公司 | Anti-noise method and device for touch screen |
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