WO2022061875A1 - 触控芯片、触控检测信号的处理方法和电子设备 - Google Patents

触控芯片、触控检测信号的处理方法和电子设备 Download PDF

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Publication number
WO2022061875A1
WO2022061875A1 PCT/CN2020/118360 CN2020118360W WO2022061875A1 WO 2022061875 A1 WO2022061875 A1 WO 2022061875A1 CN 2020118360 W CN2020118360 W CN 2020118360W WO 2022061875 A1 WO2022061875 A1 WO 2022061875A1
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signal
scanning period
phase
line scanning
line
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PCT/CN2020/118360
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English (en)
French (fr)
Inventor
沈海明
包宇洋
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深圳市汇顶科技股份有限公司
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Priority to PCT/CN2020/118360 priority Critical patent/WO2022061875A1/zh
Publication of WO2022061875A1 publication Critical patent/WO2022061875A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means

Definitions

  • the embodiments of the present application relate to the field of information technology, and more particularly, to a touch control chip, a method for processing a touch detection signal, and an electronic device.
  • the control detection signal is synchronized with the line scan period of the line synchronization signal of the display layer, so as to reduce the noise influence of the display layer on the touch layer.
  • the line scanning period of the line synchronization signal of the display layer is unstable, the corresponding touch detection signal collected by the touch chip is also unstable, and the demodulation result obtained after sampling and demodulating the touch detection signal includes additional noise.
  • the instability of the line synchronization signal of the display layer brings additional noise to the touch detection of the touch layer, reduces the signal-to-noise ratio of the touch detection system, and affects the result of the touch detection.
  • Embodiments of the present application provide a touch chip, a method for processing a touch detection signal, and an electronic device, which can reduce the influence of the jitter of the line synchronization signal of the display layer in the time domain on the touch detection of the touch layer, and improve the touch control performance.
  • the signal-to-noise ratio of the detection system can reduce the influence of the jitter of the line synchronization signal of the display layer in the time domain on the touch detection of the touch layer, and improve the touch control performance.
  • a touch control chip including:
  • a driving circuit for outputting a coding signal to the touch layer of the screen according to the line scanning period of the line synchronization signal of the display layer of the screen;
  • a detection circuit for receiving the detection signal output by the touch control layer
  • a sampling circuit for sampling the detection signal to obtain sampled data
  • a demodulation circuit configured to perform quadrature demodulation according to the sampled data, and obtain a demodulation result of the detection signal, wherein the line scanning period is changed, and the line scanning period is used for quadrature demodulation
  • the moment of the 0° phase of the demodulated sine signal and the cosine signal is the same as the start moment of the line scanning period.
  • the sampling data used for the orthogonal demodulation in each line scanning period is used for demodulation.
  • the time of the 0° phase of the sine and cosine signal is the same as the time of the rising edge of the line synchronization signal in the line scanning period, so that the demodulation result obtained after quadrature demodulation is also stable, and the line synchronization of the display layer is reduced.
  • the jitter of the signal in the time domain affects the noise of the touch detection of the touch layer, which improves the signal-to-noise ratio of the touch detection system.
  • the start time of the line scan period is the time of the rising edge of the line synchronization signal in the line scan period.
  • the touch control chip further includes a phase counter, which is used for resetting when the rising edge of the line synchronization signal in the line scanning period arrives, so as to start from 0 °phase starts to record phase information; wherein, the demodulation circuit is further configured to: generate the sine signal and the cosine signal according to the phase information recorded by the reset phase counter.
  • the phase of the sine signal and the cosine signal in the line scanning period is greater than, equal to or less than a specific value, and the specific value is 180° or 360°.
  • the phase counter is further configured to: when the phase recorded in the line scanning period reaches the specific value, continue to record the phase information based on the specific value until the next line scanning period The rising edge of the line sync signal within the time comes.
  • the phase counter is further configured to: when the phase recorded in the line scanning period reaches the specific value, suspend the recording of phase information until the line synchronization of the next line scanning period The time of the rising edge of the signal arrives.
  • the phase counter is further configured to: when the rising edge of the line synchronization signal in the next line scanning period arrives, if the recorded phase does not reach the specific value, perform a repeat operation. set.
  • the touch detection signal in each line scanning period can be detected by the phase reset method or the phase pause method.
  • the phase counter can start counting from the 0° phase when the rising edge of the line synchronization signal in each line scanning period arrives, and if the rising edge of the line synchronization signal in the next line scanning period arrives, the phase counter records If the phase of the phase has not reached 360°, reset the phase counter to start counting again from the 0° phase when the rising edge of the line synchronization signal in the next line scan period arrives; if the line synchronization signal in the next line scan period Before the arrival of the rising edge, the phase recorded by the phase counter has reached 360°, and the recording phase can be suspended or continued for 360° until the rising edge of the line synchronization signal in the next line scanning period arrives.
  • the touch control chip further includes a buffer circuit, configured to: buffer the data obtained in the line scanning period before the demodulation circuit performs quadrature demodulation according to the sampled data.
  • the sampled data wherein, the demodulation circuit is further configured to: after the line scanning period ends, generate the sine signal and the cosine signal according to the sampled data.
  • the number of sampling points corresponding to the sampling data in different row scanning periods is the same or different.
  • a data buffering method can also be used to process the touch detection signal in each line scan period. For example, the sampling data of the touch detection signal in the line scanning period is cached first, so that after the line scanning period ends, the detection signal is demodulated according to the sampling data that can be obtained in the line scanning period, and the demodulation result is obtained. , so that the demodulation result is completely synchronized with the line scanning period.
  • the demodulation circuit is further configured to: according to the demodulation result in the line scanning period and the demodulation result in the adjacent line scanning period, use a correlation dual The sampling method determines the result of touch detection.
  • Correlated Double Sampling is performed on the touch detection signals collected in two adjacent line scan periods, so that the touch detection result has a higher signal-to-noise ratio.
  • the sampling circuit is further configured to: sample the line synchronization signal or the detection signal to obtain sampled data; perform interpolation and fitting on the sampled data to improve the The sampling rate of the sampling data; according to the sampling data after the sampling rate is increased, determine the time of the rising edge of the line synchronization signal in the line scanning period, wherein the adjacent sampling data after the sampling rate is increased The time interval between two sampling points is less than or equal to the jitter value of the line scanning period in the time domain.
  • a sampling circuit may be used to sample the horizontal synchronization signal or the touch detection signal, so as to determine the time of the rising edge of the horizontal synchronization signal. Therefore, it is necessary to increase the number of sampling points of the sampling circuit to match the jitter value of the line scanning period, so that the time of the rising edge of the line synchronization signal can be accurately collected.
  • a method for processing a touch detection signal including:
  • sampling the detection signal to obtain sampling data
  • the sampling data used for the orthogonal demodulation in each line scanning period is used for demodulation.
  • the time of the 0° phase of the sine and cosine signal is the same as the time of the rising edge of the line synchronization signal in the line scanning period, so that the demodulation result obtained after quadrature demodulation is also stable, and the line synchronization of the display layer is reduced.
  • the jitter of the signal in the time domain affects the noise of the touch detection of the touch layer, which improves the signal-to-noise ratio of the touch detection system.
  • the start time of the line scan period is the time of the rising edge of the line synchronization signal in the line scan period.
  • the method further includes: when the rising edge of the line synchronization signal in the line scanning period arrives, resetting the phase counter, so that the phase counter changes from 0° Phase starts to record phase information; and generates the sine signal and the cosine signal according to the phase information recorded by the reset phase counter.
  • the phase of the sine signal and the cosine signal in the line scanning period is greater than, equal to or less than a specific value, and the specific value is 180° or 360°.
  • the method further includes: when the phase recorded by the phase counter in the line scanning period reaches the specific value, continuing to record the phase information based on the specific value until the next The time of the rising edge of the line synchronization signal in the line scanning period comes.
  • the method further includes: when the phase recorded by the phase counter in the line scanning period reaches the specific value, suspending the recording of the phase information until all the phase information of the next line scanning period is reached. The timing of the rising edge of the row sync signal arrives.
  • the method further includes: when the rising edge of the line synchronization signal in the next line scanning period arrives, if the phase recorded by the phase counter does not reach the specific value, then Reset the phase counter.
  • the touch detection signal in each line scanning period can be detected by the phase reset method or the phase pause method.
  • the phase counter can start counting from the 0° phase when the rising edge of the line synchronization signal in each line scanning period arrives, and if the rising edge of the line synchronization signal in the next line scanning period arrives, the phase counter records If the phase of the phase has not reached 360°, reset the phase counter to start counting again from the 0° phase when the rising edge of the line synchronization signal in the next line scan period arrives; if the line synchronization signal in the next line scan period Before the arrival of the rising edge, the phase recorded by the phase counter has reached 360°, and the recording phase can be suspended or continued for 360° until the rising edge of the line synchronization signal in the next line scanning period arrives.
  • the method before performing quadrature demodulation according to the sampled data, the method further includes: buffering the sampled data obtained in the line scanning period; After the end, the sine signal and the cosine signal are generated according to the sampled data.
  • the number of sampling points corresponding to the sampling data in different row scanning periods is the same or different.
  • a data buffering method can also be used to process the touch detection signal in each line scan period. For example, the sampling data of the touch detection signal in the line scanning period is cached first, so that after the line scanning period ends, the detection signal is demodulated according to the sampling data that can be obtained in the line scanning period, and the demodulation result is obtained. , so that the demodulation result is completely synchronized with the line scanning period.
  • the method further includes: adopting a correlated double sampling method according to the demodulation result in the line scanning period and the demodulation result in the adjacent line scanning period to determine the result of touch detection.
  • Correlated double sampling is performed on the touch detection signals collected in two adjacent line scanning periods, so that the result of the touch detection has a higher signal-to-noise ratio.
  • the method further includes: sampling the line synchronization signal or the detection signal to obtain sampling data; performing interpolation and fitting on the sampling data to improve the sampling data
  • the sampling rate of The time interval between the sampling points is less than or equal to the jitter value of the line scanning period in the time domain.
  • a sampling circuit may be used to sample the horizontal synchronization signal or the touch detection signal, so as to determine the time of the rising edge of the horizontal synchronization signal. Therefore, it is necessary to increase the number of sampling points of the sampling circuit to match the jitter value of the line scanning period, so that the time of the rising edge of the line synchronization signal can be accurately collected.
  • an electronic device including the touch control chip in the first aspect or any possible implementation manner of the first aspect.
  • FIG. 1 is a schematic diagram of a screen module.
  • FIG. 2 is a schematic diagram of the relationship among the line synchronization signal, pixel data, display layer noise and touch detection signal.
  • FIG. 3 is a schematic diagram illustrating the influence of the jitter of the horizontal synchronization signal on the touch detection signal.
  • FIG. 4 is a schematic diagram of the timing of the downlink synchronization signal, sampled data and sinusoidal signal under ideal conditions.
  • FIG. 5 is a schematic diagram of the timing of the horizontal synchronization signal, the sampled data and the sinusoidal signal when the horizontal scanning period is unstable.
  • FIG. 6 is a schematic block diagram of a touch control chip according to an embodiment of the present application.
  • FIG. 7 is a schematic diagram of a phase reset method according to an embodiment of the present application.
  • FIG. 8 is a schematic diagram of a phase suspension method according to an embodiment of the present application.
  • FIG. 9 is a schematic diagram of a data caching method according to an embodiment of the present application.
  • FIG. 10 is a schematic diagram of correlated double sampling according to an embodiment of the present application.
  • FIG. 11 is a schematic flowchart of a method for processing a touch detection signal according to an embodiment of the present application.
  • the screens of electronic devices are being made thinner and thinner to reduce the thickness of the electronic device, or to allow more space in the electronic device to accommodate other internal components within the same thickness.
  • LCD liquid crystal display
  • OLED Organic Light Emitting Diode
  • the basic capacitance of the touch electrodes in the touch layer of the screen increases, and the noise coupled from the display layer to the touch layer increases, which directly affects the performance and sensitivity of touch detection. .
  • Figure 1 shows a schematic diagram of the screen module.
  • the touch layer and the display layer in the screen module are usually two independent and separate systems. In theory, there may be no or little interference between them. However, as today's screens are getting thinner and thinner, the touch electrodes in the touch layer are closer to the system ground, so that the self-capacitance of the touch electrodes to the system ground has increased from about 100pF before to about 500pF now. As a result, the interaction between the touch layer and the display layer cannot be ignored.
  • the signal generated by the display driver chip is transmitted to the display layer of the screen module, and is coupled to the system ground of the touch layer and the display layer through the parasitic capacitance C D of the trace, and then passes through the touch layer in the touch layer.
  • the ground capacitances C sg and C dg of the control electrodes are coupled to the touch layer, so that display layer noise is formed on the touch layer, and finally coupled to the touch chip, thereby affecting the performance of touch detection.
  • the display driving chip generates a line synchronization signal (referred to as Hsync signal) as a clock to update pixel data (or called display data) of pixels in each row of the display layer. Since the basic capacitance of the touch electrodes of the touch layer becomes larger, when the pixel data of each row of pixels is refreshed, the signal input to the display layer will be coupled from the common cathode between the touch layer and the display layer to the touch electrodes of the touch layer. , and ultimately affect touch detection. That is, there is synchronization between the display layer noise coupled from the display layer to the touch layer and the Hsync signal of the display layer.
  • Hsync signal a line synchronization signal
  • FIG. 2 shows the relationship among the line synchronization signal, pixel data, display layer noise, and touch detection signal (hereinafter also referred to as detection signal for short).
  • the display driver chip uses the Hsync signal as the clock to update the pixel data (or display data) of each row of pixels in the display layer, and the display layer noise is generated when the pixel data is refreshed, so the display layer noise is synchronized with the Hsync signal .
  • the touch coding signal (also referred to as coding signal or driving signal) output during touch detection can be synchronized with the Hsync signal, so that the The detection signal is also synchronized with the Hsync signal, that is, a constant phase difference is maintained, thereby reducing the interference of display layer noise on touch detection to a certain extent.
  • the detection signal is acquired during the low noise period in the line scanning period, and the detection signal is synchronized with the Hsync signal. Based on the detection signal, the user's touch information, such as touch position, touch pressure, etc., can be obtained.
  • the touch coding signal described in the embodiments of the present application refers to the coding signal output by the touch control chip during the touch detection, including the coding signal input to the touch layer; it also includes the output during the touch detection.
  • the display driver chip generates the Hsync signal through the internal RC oscillator circuit. Because the clock of the RC oscillator circuit itself has poor precision and large temperature drift, the generated Hsync signal has jitter, which is manifested in that the line scanning period of the Hsync signal may change slightly, so the display layer noise coupled to the touch layer There is also jitter. When an edge of a certain Hsync signal triggers the sampling circuit in the touch chip to collect the detection signal, the jitter of the line scan period will be transferred from one line scan period to the next line scan period in the time domain and superimposed. The longer the continuous sampling time, the greater the jitter of the collected detection signal.
  • the detection signal When the noise of the display layer coupled from the display layer to the touch layer increases, the detection signal still needs to have a certain signal-to-noise ratio.
  • the coding signal also called the driving signal
  • the touch chip can be synchronized with the Hsync signal , so as to eliminate the interference of display layer noise on touch detection to a certain extent.
  • the detection signal collected by the touch chip is also unstable, and the demodulation result after sampling and demodulating the detection signal is also unstable.
  • the tuning result jitters within a certain range. In this way, the instability of the line scanning period will bring additional noise to the touch detection, which affects the result of the touch detection.
  • one line synchronization scanning period of the Hsync signal is ideally stable without jitter.
  • the jitter value of the line scanning period in practical applications is ⁇ 10ns, as shown in the first row of FIG. 3 .
  • the sampling circuit in the touch chip is triggered by the rising edge of a certain Hsync signal, and continuously samples the detection signal of 1ms, as shown in the second row of FIG. 3 .
  • the line scanning period is stable, and the sampling circuit samples the detection signal for a total of 100 periods, as shown in the third row of FIG. 3 .
  • the actual sampling period of the sampling circuit is 99.9 to 100.1.
  • the sampling data collected by the sampling circuit is first subjected to quadrature demodulation (also called IQ demodulation or quadrature IQ demodulation) to obtain the demodulation result of the detection signal, and then sent to the The processor performs the calculation of touch coordinates.
  • the last row of FIG. 3 shows the sine signal (Sin signal) used to demodulate the sampled data. Since the cosine signal (Cos signal) and the sine signal are processed in the same way in the embodiment of the present application, the sine signal is used as an example below. describe. In this case, the detection signal has jitter in the time domain but the sinusoidal signal used for quadrature demodulation does not have jitter in the time domain.
  • the demodulation result is also jittered, which is embodied in the jitter of the signal amplitude obtained by demodulation.
  • the jitter of the demodulation result is the noise superimposed on the valid signal.
  • the noise floor of the circuit system is ignored, and it is assumed that no external object touches the touch electrodes to change the amplitude of the detection signal.
  • FIG. 4 and FIG. 5 respectively show the influence on quadrature demodulation when there is no jitter in the line scan period and in the presence of jitter, in which only the sinusoidal signal used for quadrature demodulation is shown.
  • Figure 4 when there is no jitter in the line scanning period, the number of sampling points when sampling the detection signal in each line scanning period is fixed, because the sine and cosine signals used for quadrature demodulation are It is generated according to a fixed frequency within a sampling period of time, and there is no jitter in the time domain relative to the detection signal, so the demodulation result obtained after demodulation is also stable.
  • the number of sampling points when the detection signal is sampled in each line scanning period is constantly changing. It is generated at a fixed frequency, such as the Sin0 signal in Figure 5. Due to the jitter of the line scanning period, the Sin0 signal of the sampled data of a certain line scanning period may correspond to the detection signal of other line scanning periods, which brings great influence to the demodulation results. error. Moreover, since the line scanning period is a random jitter, the timing and phase of the Sin0 signal corresponding to the detection signals of other line scanning periods are different, resulting in constant changes in the demodulation result error. In this way, the noise in the demodulation result obtained by demodulating the detection signal will increase.
  • the present application proposes a solution for processing the detection signal, which can obtain the sine signal and cosine signal due to quadrature demodulation as shown in the Sin0' signal in FIG. 5 . , thereby reducing the influence of the Hsync signal of the display layer on the touch detection result and improving the signal-to-noise ratio of the touch detection system.
  • a solution for processing the detection signal which can obtain the sine signal and cosine signal due to quadrature demodulation as shown in the Sin0' signal in FIG. 5 . , thereby reducing the influence of the Hsync signal of the display layer on the touch detection result and improving the signal-to-noise ratio of the touch detection system.
  • FIG. 6 is a schematic block diagram of a touch control chip according to an embodiment of the present application.
  • the touch chip 600 includes a driving circuit 610 , a detection circuit 620 , a sampling circuit 630 and a demodulation circuit 640 .
  • the driving circuit 610 is configured to output a coding signal to the touch layer of the screen according to the line scanning period of the line synchronization signal of the display layer of the screen.
  • the detection circuit 620 is configured to receive the detection signal output by the touch layer.
  • the sampling circuit 630 is used for sampling the detection signal to obtain sampling data.
  • the demodulation circuit 640 is configured to perform quadrature demodulation according to the sampled data to obtain a demodulation result of the detection signal.
  • the demodulation result mentioned here refers to the signal amplitude of the detection signal obtained by demodulating the detection signal.
  • the line scanning period varies, and the time of the 0° phase of the sine signal and the cosine signal used for quadrature demodulation in the line scanning period is the same as the starting time of the line scanning period.
  • the start time of each line scan period may be, for example, the time of the rising edge of the line synchronization signal in the line scan period, or the time of the falling edge of the line synchronization signal in the previous line scan period.
  • the detection signal can be processed based on the above method, and finally the sine signal and cosine signal used for quadrature demodulation in this sampling time can be obtained, and based on the sine signal
  • the detection signal is quadrature demodulated with the cosine signal, so as to obtain the demodulation result within the sampling time.
  • the driving circuit 610 outputs the coding signal and the detection circuit 620 receives the corresponding detection signal, which may be performed synchronously.
  • the detection circuit 620 receives the detection signal output from the touch layer.
  • the detection signal carries the user's touch information, such as the capacitance change of the touch electrode caused by the user's touch. After subsequent processing of the detection signal, the user's touch information can be obtained.
  • the line scanning period described here is varied, which means that the line scanning period or the line scanning signal has jitter in the time domain. That is, the output of the line synchronization signal of the display layer is unstable in the time domain, or the line scanning period is unstable in the time domain.
  • the line scanning period is stable in the time domain, and the length of each line scanning period is 10us; and when the line scanning period is unstable in the time domain, its length is 10us ⁇ 10ns, and there is a range of 10ns Vibration within.
  • the number of sampling points corresponding to the sampled data in different line scanning periods may be the same or different.
  • phase of the obtained sine signal and cosine signal in the line scanning period may be greater than, equal to or less than a specific value.
  • the specific value is 360°; in some implementations, for example, when the detection signal is processed by means of correlated double sampling, the specific value may be 180°.
  • the above-mentioned line scanning period takes the period between the rising edges of the pulses of two adjacent line synchronization signals as a line scanning period as an example to describe the embodiments of the present application. Therefore, in each line scanning period, the The 0° phase moment of the sine signal and cosine signal used for quadrature demodulation is the same as the moment of the rising edge of the line synchronization signal in each line scanning period.
  • the sine signal and cosine signal used for quadrature demodulation in each line scanning period The time of the 0° phase is the same as the time of the falling edge of the line synchronization signal in the previous line scanning period.
  • This embodiment of the present application does not limit how to divide the line scan period, and the sampling circuit 630 starts sampling the detection signal in the line scan period from the start time of the line scan period.
  • the present application provides three processing methods for detection signals, which will be described below with reference to FIG. 7 to FIG. 9 respectively.
  • the method 1 may also be referred to as the phase reset method
  • the method 2 may also be referred to as the phase suspension method
  • the method 3 may also be referred to as the data buffer method.
  • the touch chip 600 further includes a phase counter.
  • the phase counter is used for resetting when the rising edge of the horizontal synchronization signal in the horizontal scanning period arrives, so as to start recording phase information from the 0° phase.
  • the demodulation circuit 640 is specifically configured to: generate a sine signal and a cosine signal according to the phase information recorded by the reset phase counter.
  • the recording of the phase information is to count, for example, counting from 0 in units of 1, that is, 0, 1, 2, 3 . . .
  • the demodulation circuit 640 generates sine and cosine signals for quadrature demodulation using the value recorded by the phase counter as the phase-dependent variable.
  • phase information continues to be recorded based on the specific value until the time of the rising edge of the line synchronization signal in the next line scanning period arrives; and/or, the phase counter is in the next line scanning period.
  • the rising edge of the line synchronization signal in one line scanning period arrives, if the recorded phase does not reach the specific value, reset is performed.
  • T0 is the line scanning period under ideal conditions, the line scanning period has no jitter in the time domain, and the length and frequency of the line scanning period are stable.
  • T1, T2, and T3 are line scan periods in practical applications. Due to the jitter of the line scan periods in the time domain, the length of each line scan period is slightly different.
  • the phase counter in FIG. 7 is the phase counter of the Sin signal, and it is assumed that the step size of the recording phase is 1°.
  • phase counter 1 does not continue to record the phase at the arrival of the rising edge of the line synchronization signal in the next line scan period, but re-records the phase of the Sin 1 signal in the next line scan from 1° after reset.
  • the phase counter 1 records the phase of the Sin 1 signal in the period T1, and at the time when the rising edge of the line synchronization signal in the period T2 arrives, the phase recorded by the phase counter 1 is equal to 358°, not reaching 360° . At this time, the phase counter 1 does not continue to record the phase after 358°, but is reset, and starts to record the phase of the Sin 1 signal of the period T2 from 0°.
  • phase counter 1 then continues to record the phase of the Sin 1 signal in the current line scanning period by 360° and exceeds 360° until the time of the rising edge of the line synchronization signal in the next line scanning period is reset to start recording from 0° Phase of the Sin 1 signal for the next line scan period.
  • the phase counter 1 records the phase of the Sin 1 signal in the period T2, and when the recorded phase reaches 360°, the rising edge of the line synchronization signal in the period T3 has not yet arrived. At this time, the phase counter 1 continues to record the phase of the Sin 1 signal in the period T2 by 360°.
  • the phase recorded by the phase counter 1 reaches 362°, the time of the rising edge of the line sync signal of the period T3 comes, at this time the phase counter 1 is reset, and starts to record the phase of the Sin 1 signal of the period T3 from 0°.
  • the phase counter suspends recording the phase information until the rising edge of the line synchronization signal in the next line scanning period arrives; and/or, the phase counter is in the next line scanning period.
  • the rising edge of the line sync signal comes, if the recorded phase does not reach the specific value, it will be reset.
  • T0 is an ideal line scanning period
  • the line scanning period has no jitter in the time domain, and the length and frequency of the line scanning period are stable.
  • T1, T2, and T3 are line scan periods in practical applications. Due to the jitter of the line scan periods in the time domain, the length of each line scan period is slightly different.
  • the demodulation circuit is a hardware circuit, and the Sin signal and Cos signal for quadrature demodulation are usually generated by the look-up table method. In Figure 8, only the Sin signal is taken as an example, and the phase counter in Figure 8 is Sin The phase counter of the signal, and it is assumed that the phase is recorded in steps of 1°.
  • phase counter 2 does not continue to record the phase at the arrival of the rising edge of the line synchronization signal in the next line scan period, but re-records the phase of Sin 2 in the next line scan from 0° after reset.
  • the phase counter 2 records the phase of the Sin 2 signal in the period T1, and, at the time when the rising edge of the line synchronization signal in the period T2 arrives, the phase recorded by the phase counter 2 is equal to 358°, and does not reach 360° . At this time, the phase counter 2 does not continue to record the phase after 358°, but is reset, and starts to record the phase of the Sin 2 signal of the period T2 from 0°.
  • phase counter 2 suspends recording the phase of the Sin 2 signal in the current line scanning period and keeps the phase of the Sin 2 signal constant at 360° until the time of the rising edge of the line synchronizing signal in the next line scanning period. 0° starts recording the phase of the Sin 2 signal for the next line scan period.
  • the phase counter 2 records the phase of the Sin 2 signal in the period T2, and when the recorded phase reaches 360°, the rising edge of the line synchronization signal in the period T3 has not yet arrived. At this time, the phase counter 2 suspends recording the phase and keeps the phase of the Sin 2 signal within the period T2 at 360°. When the rising edge of the line sync signal of the period T3 comes, the phase counter 2 is reset at this time, and starts to record the phase of the Sin 2 signal of the period T3 from 0°.
  • the phase of the Sin 1 signal in the period T2 in FIG. 8 is 360°.
  • Modes 2 and 1 only need to adjust the phase counting mode of the phase counter without adding additional circuit structure, so that the influence of the jitter of the line scanning period on the demodulation result can be avoided, and the signal-to-noise ratio of the touch detection system can be improved.
  • the touch chip 600 further includes a buffer circuit for: buffering the sampled data obtained in the line scanning period before the demodulation circuit 640 performs quadrature demodulation according to the sampled data.
  • the demodulation circuit 640 is specifically configured to: after the line scanning period ends, generate a sine signal and a cosine signal according to the sampled data.
  • the sampling circuit 630 may be, for example, an ADC circuit. As shown in FIG. 9 , taking a sinusoidal signal as an example, when the sampling circuit 630 starts sampling, each sampling point is first buffered, and the Sin 3 signal for quadrature demodulation is not started to be generated at this time. Until the sampling circuit 630 completes the acquisition of the detection signal in each line scan period, generates the Sin 3 signal at the sampling point in each line scan period, and then according to the Sin 3 signal corresponding to each line scan period and the buffered signal. The detection signal in the line scanning period is subjected to quadrature demodulation.
  • the demodulation circuit 640 After the sampling circuit 630 collects the detection signal in the period T1, and the period T1 contains 6 sampling points, the demodulation circuit 640 generates a Sin 3 signal containing 6 sampling points and an initial phase of 0° After the sampling circuit 630 collects the detection signal in the period T2, and includes 7 sampling points in the period T2, then the demodulation circuit 640 generates a Sin 3 signal that includes 7 sampling points and an initial phase of 0°; the sampling circuit 630 pairs After the detection signal collection in the period T3 is completed, and the period T3 includes 8 sampling points, the demodulation circuit 640 generates a Sin 3 signal including 8 sampling points and an initial phase of 0°.
  • Figure 9 only shows the period T1, period T2 and period T3 in the sampling time, and in other periods after that, the corresponding Sin 3 signal for quadrature demodulation of the detection signal in the corresponding period is obtained in a similar manner .
  • quadrature demodulation is performed on the detection signal in the sampling time, so as to obtain the demodulation result in the sampling time.
  • Mode 3 can completely synchronize the sine signal and cosine signal used for quadrature demodulation with the horizontal synchronization signal, completely eliminating the influence of the jitter of the horizontal scanning period in the time domain and frequency domain on the demodulation result.
  • Mode 3 is the best way to eliminate the effect of jitter.
  • the sampling points of at least one line scanning period need to be buffered in advance, and the demodulation result can be output after at least one line scanning period.
  • 360° is used as an example.
  • a correlated double sampling manner may also be used to process the detection signal.
  • the specific values corresponding to two adjacent line scanning periods are 180° and 360°, respectively.
  • the touch chip 600 further includes a processing circuit configured to: adopt a correlated double sampling method according to the demodulation result in the line scanning period and the demodulation result in the adjacent line scanning period, Determine the result of touch detection.
  • the detection signal is processed by means of correlated double sampling, which can further eliminate the noise in the demodulation result and improve the signal-to-noise ratio of the touch detection system.
  • the reference phase counter 4 and the Sin 4 signal when the line scanning period is stable, the reference phase counter 4 and the Sin 4 signal; when the line scanning period is unstable, the reference phase counter 5 and the Sin 5 signal.
  • mode 1 when performing correlated double sampling, when the rising edge of the line scanning signal in period T2 arrives, when the phase recorded by phase counter 5 in period T1 is 178°, then phase counter 5 is reset and starts from 180°.
  • the embodiment of the present application also provides a method for judging the rising edge of a line scan signal.
  • the sampling circuit 620 is used for: sampling the line synchronization signal or the detection signal to obtain sampling data; performing interpolation and fitting on the sampling data to increase the sampling rate of the sampling data; according to the sampling data after increasing the sampling rate , to determine the time of the rising edge of the line synchronization signal in the line scanning period.
  • the time interval between two adjacent sampling points of the sampled data after the sampling rate is increased is less than or equal to the jitter value of the line scanning period in the time domain.
  • the sampling frequency when the sampling circuit 620 samples the detection signal is not too high.
  • the data collected by the sampling circuit 620 can be interpolated, fitted, etc. The method increases the sampling rate before making a judgment.
  • the sampling frequency of the sampling circuit 620 is 2MHz
  • the error of using the raw data collected by the sampling circuit to judge the rising edge is one sampling period, that is, 0.5us, which is far longer than the jitter value of the line scanning period of most screens, such as ⁇ 10ns. jitter value.
  • 49 sampling points are interpolated between every two adjacent sampling points, and the judgment error of the rising edge of the horizontal synchronization signal becomes 10ns, which ensures the accuracy of the judgment of the rising edge.
  • interpolation methods here include, but are not limited to, linear interpolation, nonlinear interpolation, and a combination of the two; fitting methods include, but are not limited to, linear fitting, nonlinear fitting, and a combination of the two.
  • Table 1 shows the touch detection results obtained when the detection signal processing method according to the embodiment of the present application is adopted. Assuming that the touch detection time is 500us, the touch detection is self-capacitance detection. As shown in Table 1, when the scheme of the present application is not adopted, in the low-noise picture, the medium-noise picture, the high-noise picture and the dynamic video, the signal-to-noise ratio (Signal Noise Ratio, SNR) of the detection result is 7.86, 6.40, 2.82 and 6.11; when the solution of the present application is adopted, in low-noise pictures, medium-noise pictures, high-noise pictures and dynamic videos, the signal-to-noise ratios of the detection results are 7.86, 7.14, 3.70 and 6.32 respectively. Therefore, by using the solutions of the embodiments of the present application, the performance of touch detection can be improved to 1.00, 1.12, and 1.03 times the original in low-noise, medium-noise, high-noise, and dynamic videos,
  • the signal processing method of the present application can effectively reduce the influence of the jitter of the line scanning period on the detection result, and improve the signal-to-noise ratio of the touch detection system.
  • the improvement can be 0-31%.
  • Table 2 shows the effect of coding time on the results of touch detection. It is assumed that the test image is a high-noise image, and the touch detection is self-capacitance detection. It can be seen from Table 2 that after adopting the scheme of the present application, the signal-to-noise ratio of the detection result has been significantly improved. Moreover, with the increase of the coding time and the detection time, the more serious the jitter of the line scanning period is, the more obvious the signal-to-noise ratio of the detection result is improved after the scheme of the present application is adopted, especially when the coding time is 250us, 500us and 1ms. , the signal-to-noise ratio can be improved to 101.2%, 143.0% and 332.4% of the original, respectively.
  • the present application eliminates or weakens the influence of the jitter of the line scanning period on the detection result from the perspective of signal demodulation.
  • the line scanning period jitter causes the line scanning period later in the sampling time to have obvious left and right jitter in the time domain, which causes the signal amplitude of the back-end digital demodulation to change.
  • the amplitude of this change is noise for the effective signal. That is, the jitter of the line scan period will bring additional noise to the touch detection.
  • using the solution of the present application eliminates or weakens the extra noise caused by the jitter of the line scanning period to the touch detection system.
  • the present application also provides a method for processing a touch detection signal. As shown in FIG. 11 , the method 1100 may be performed by the above-mentioned touch control chip 600 . The method 1100 includes some or all of the following steps.
  • step 1110 according to the line scanning period of the line synchronization signal of the display layer of the screen, a coding signal is output to the touch layer of the screen, and a detection signal output by the touch layer is received.
  • step 1120 the detection signal is sampled to obtain sampled data.
  • step 1130 orthogonal demodulation is performed according to the sampled data to obtain a demodulation result of the detection signal, wherein the line scanning period is changed, and the line scanning period is used to perform orthogonal solution.
  • the time of the 0° phase of the modulated sine signal and the cosine signal is the same as the time of the rising edge of the line synchronization signal in the line scanning period.
  • the sine and cosine signals used for quadrature demodulation in each line scanning period are 0.
  • the time of ° phase is the same as the time of the rising edge of the horizontal synchronization signal in the line scanning period, so that the demodulation result obtained after quadrature demodulation is also stable, and the time domain of the horizontal synchronization signal of the display layer is reduced.
  • the impact of the jitter on the noise of the touch detection of the touch layer is improved, and the signal-to-noise ratio of the touch detection system is improved.
  • the method further includes: when the time of the rising edge of the line synchronization signal in the line scan period arrives, resetting the phase counter, so that the phase counter is changed from The 0° phase starts to record phase information; the sine signal and the cosine signal are generated according to the phase information recorded by the reset phase counter.
  • the phase of the sine signal and the cosine signal in the line scanning period is greater than, equal to, or less than a specific value, and the specific value is 180° or 360°.
  • the method further includes: when the phase recorded by the phase counter in the line scanning period reaches the specific value, continuing to record the phase information based on the specific value until The time of the rising edge of the line synchronization signal in the next line scanning period comes.
  • the method further includes: when the phase recorded by the phase counter in the line scanning period reaches the specific value, suspending recording phase information until the next line scanning period The time of the rising edge of the line synchronization signal arrives.
  • the method further includes: when the rising edge of the line synchronization signal in the next line scan period arrives, if the phase recorded by the phase counter does not reach the specific value , the phase counter is reset.
  • the method before performing quadrature demodulation according to the sampled data, the method further includes: buffering the sampled data obtained in the line scanning period; After the scanning period ends, the sine signal and the cosine signal are generated according to the sampled data.
  • the number of sampling points corresponding to the sampling data in different line scanning periods is the same or different.
  • the method further includes: adopting correlated double sampling according to the demodulation result in the line scanning period and the demodulation result in the adjacent line scanning period. way to determine the result of touch detection.
  • the method further includes: sampling the line synchronization signal or the detection signal to obtain sampling data; performing interpolation and fitting on the sampling data to improve the The sampling rate of the sampling data; according to the sampling data after the sampling rate is increased, determine the time of the rising edge of the line synchronization signal in the line scanning period, wherein the adjacent sampling data after the sampling rate is increased The time interval between two sampling points is less than or equal to the jitter value of the line scanning period in the time domain.
  • the embodiment of the present application further provides an electronic device, the electronic device includes: a screen; and the touch chip in the above-mentioned various embodiments of the present application.
  • the electronic device in the embodiment of the present application may be a portable or mobile computing device such as a terminal device, a mobile phone, a tablet computer, a notebook computer, a desktop computer, a game device, a vehicle-mounted electronic device, or a wearable smart device, and Electronic databases, automobiles, bank ATMs (Automated Teller Machine, ATM) and other electronic devices.
  • the wearable smart device includes full functions, large size, and can realize complete or partial functions without relying on smart phones, such as smart watches or smart glasses, etc., and only focus on a certain type of application function, which needs to cooperate with other devices such as smart phones. Use, such as various types of smart bracelets, smart jewelry and other equipment for physical monitoring.

Abstract

一种触控芯片（600）、触控检测信号的处理方法和电子设备，能够降低显示层的行同步信号在时域上的抖动对触控层的触控检测的影响，提高触控检测系统的信噪比。所述触控芯片（600）包括：驱动电路（610），用于根据屏幕的显示层的行同步信号的行扫描周期，向所述屏幕的触控层输出打码信号；检测电路（620），用于接收所述触控层输出的检测信号；采样电路（630），用于对所述检测信号进行采样，得到采样数据；以及，解调电路（640），用于根据所述采样数据进行正交解调，得到所述检测信号的解调结果，其中，所述行扫描周期是变化的，所述行扫描周期内的用于进行正交解调的正弦信号和余弦信号的0°相位的时刻，与所述行扫描周期的起始时刻相同。

Description

触控芯片、触控检测信号的处理方法和电子设备 技术领域
本申请实施例涉及信息技术领域，并且更具体地，涉及一种触控芯片、触控检测信号的处理方法和电子设备。
背景技术
随着电子设备的屏幕越来越薄，屏幕中的触控层与显示层之间的距离越来越近，显示层和触控层之间存在相互影响，因此可以使触控芯片获取的触控检测信号与显示层的行同步信号的行扫描周期之间同步，以降低显示层对触控层的噪声影响。但是，当显示层的行同步信号的行扫描周期不稳定时，触控芯片采集到的相应的触控检测信号也就不稳定，对触控检测信号进行采样和解调后得到的解调结果中就包括额外的噪声。这样，显示层的行同步信号的不稳定，就给触控层的触控检测带来了额外的噪声，降低了触控检测系统的信噪比，影响触控检测的结果。
发明内容
本申请实施例提供一种触控芯片、触控检测信号的处理方法和电子设备，能够降低显示层的行同步信号在时域上的抖动对触控层的触控检测的影响，提高触控检测系统的信噪比。
第一方面，提供了一种触控芯片，包括：
驱动电路，用于根据屏幕的显示层的行同步信号的行扫描周期，向所述屏幕的触控层输出打码信号；
检测电路，用于接收所述触控层输出的检测信号；
采样电路，用于对所述检测信号进行采样，得到采样数据；以及，
解调电路，用于根据所述采样数据进行正交解调，得到所述检测信号的解调结果，其中，所述行扫描周期是变化的，所述行扫描周期内的用于进行正交解调的正弦信号和余弦信号的0°相位的时刻，与所述行扫描周期的起始时刻相同。
基于上述技术方案，当显示层的行同步信号的行扫描周期不稳定时，对触控检测信号的采样数据进行解调时，通过使每个行扫描周期内的用于进行 正交解调的正余弦信号的0°相位的时刻，与该行扫描周期内的行同步信号的上升沿的时刻相同，从而使正交解调后得到的解调结果也是稳定的，降低了显示层的行同步信号在时域上的抖动对触控层的触控检测的噪声影响，提高了触控检测系统的信噪比。
在一种可能的实现方式中，所述行扫描周期的起始时刻为所述行扫描周期内的所述行同步信号的上升沿的时刻。
在一种可能的实现方式中，所述触控芯片还包括相位计数器，用于：在所述行扫描周期内的所述行同步信号的上升沿的时刻到来时，进行重置，以从0°相位开始记录相位信息；其中，所述解调电路还用于：根据重置后的所述相位计数器记录的相位信息，生成所述正弦信号和所述余弦信号。
在一种可能的实现方式中，所述行扫描周期内的所述正弦信号和所述余弦信号的相位大于、等于或者小于特定值，所述特定值为180°或者360°。
在一种可能的实现方式中，所述相位计数器还用于：当所述行扫描周期内记录的相位达到所述特定值时，基于所述特定值继续记录相位信息，直至下一个行扫描周期内的所述行同步信号的上升沿的时刻到来。
在一种可能的实现方式中，所述相位计数器还用于：当所述行扫描周期内记录的相位达到所述特定值时，暂停记录相位信息，直至下一个行扫描周期的所述行同步信号的上升沿的时刻到来。
在一种可能的实现方式中，所述相位计数器还用于：在下一个行扫描周期内的所述行同步信号的上升沿到来时，若所记录的相位未达到所述特定值，则进行重置。
可以采用相位重置法或者相位暂停法对每个行扫描周期内的触控检测信号。例如，相位计数器可以在每个行扫描周期内的行同步信号的上升沿到来时从0°相位开始计数，如果在下一个行扫描周期内的行同步信号的上升沿到来的时刻，该相位计数器记录的相位还未达到360°，则重置相位计数器以在下一个行扫描周期内的行同步信号的上升沿到来的时刻重新从0°相位开始计数；如果在下一个行扫描周期内的行同步信号的上升沿到来的时刻之前，该相位计数器记录的相位已经达到360°，则可以暂停记录相位或者接着360°继续记录相位，直至下一个行扫描周期内的行同步信号的上升沿到来。
在一种可能的实现方式中，所述触控芯片还包括缓存电路，用于：在所 述解调电路根据所述采样数据进行正交解调之前，缓存所述行扫描周期内得到的所述采样数据；其中，所述解调电路还用于：在所述行扫描周期结束后，根据所述采样数据生成所述正弦信号和所述余弦信号。
在一种可能的实现方式中，不同的所述行扫描周期内的所述采样数据对应的采样点数量相同或者不同。
还可以采用数据缓存法对每个行扫描周期内的触控检测信号进行处理。例如，先缓存行扫描周期内的触控检测信号的采样数据，从而在该行扫描周期结束之后，根据在该行扫描周期内能够获得的采样数据，对检测信号进行解调，得到解调结果，以使该解调结果与该行扫描周期完全同步。
在一种可能的实现方式中，所述解调电路还用于：根据所述行扫描周期内的所述解调结果和与其相邻的行扫描周期内的所述解调结果，采用相关双采样的方式，确定触控检测的结果。
对相邻两个行扫描周期内采集到的触控检测信号，进行相关双采样(Correlated Double Sampling，CDS)，可以使触控检测的结果具有更高的信噪比。
在一种可能的实现方式中，所述采样电路还用于：对所述行同步信号或者所述检测信号进行采样，得到采样数据；对所述采样数据进行插值和拟合，以提升所述采样数据的采样率；根据提升采样率之后的所述采样数据，确定所述行扫描周期内的所述行同步信号的上升沿的时刻，其中，提升采样率之后的所述采样数据的相邻两个采样点之间的时间间隔小于或者等于所述行扫描周期在时域上的抖动值。
可以利用采样电路对行同步信号或者触控检测信号进行采样，从而确定行同步信号的上升沿的时刻。为此，需要增加采样电路的采样点数，以匹配行扫描周期的抖动值，才能够精准地采集到行同步信号的上升沿的时刻。
第二方面，提供了一种触控检测信号的处理方法，包括：
根据屏幕的显示层的行同步信号的行扫描周期，向所述屏幕的触控层输出打码信号，并接收所述触控层输出的检测信号；
对所述检测信号进行采样，得到采样数据；
根据所述采样数据进行正交解调，得到所述检测信号的解调结果，其中，所述行扫描周期是变化的，所述行扫描周期内的用于进行正交解调的正弦信号和余弦信号的0°相位的时刻，与所述行扫描周期的起始时刻相同。
基于上述技术方案，当显示层的行同步信号的行扫描周期不稳定时，对触控检测信号的采样数据进行解调时，通过使每个行扫描周期内的用于进行正交解调的正余弦信号的0°相位的时刻，与该行扫描周期内的行同步信号的上升沿的时刻相同，从而使正交解调后得到的解调结果也是稳定的，降低了显示层的行同步信号在时域上的抖动对触控层的触控检测的噪声影响，提高了触控检测系统的信噪比。
在一种可能的实现方式中，所述行扫描周期的起始时刻为所述行扫描周期内的所述行同步信号的上升沿的时刻。
在一种可能的实现方式中，所述方法还包括：在所述行扫描周期内的所述行同步信号的上升沿的时刻到来时，重置相位计数器，以使所述相位计数器从0°相位开始记录相位信息；根据重置后的所述相位计数器记录的相位信息，生成所述正弦信号和所述余弦信号。
在一种可能的实现方式中，所述行扫描周期内的所述正弦信号和所述余弦信号的相位大于、等于或者小于特定值，所述特定值为180°或者360°。
在一种可能的实现方式中，所述方法还包括：当所述相位计数器在所述行扫描周期内记录的相位达到所述特定值时，基于所述特定值继续记录相位信息，直至下一个行扫描周期内的所述行同步信号的上升沿的时刻到来。
在一种可能的实现方式中，所述方法还包括：当所述相位计数器在所述行扫描周期内记录的相位达到所述特定值时，暂停记录相位信息，直至下一个行扫描周期的所述行同步信号的上升沿的时刻到来。
在一种可能的实现方式中，所述方法还包括：在下一个行扫描周期内的所述行同步信号的上升沿到来时，若所述相位计数器所记录的相位未达到所述特定值，则重置所述相位计数器。
可以采用相位重置法或者相位暂停法对每个行扫描周期内的触控检测信号。例如，相位计数器可以在每个行扫描周期内的行同步信号的上升沿到来时从0°相位开始计数，如果在下一个行扫描周期内的行同步信号的上升沿到来的时刻，该相位计数器记录的相位还未达到360°，则重置相位计数器以在下一个行扫描周期内的行同步信号的上升沿到来的时刻重新从0°相位开始计数；如果在下一个行扫描周期内的行同步信号的上升沿到来的时刻之前，该相位计数器记录的相位已经达到360°，则可以暂停记录相位或者接着360°继续记录相位，直至下一个行扫描周期内的行同步信号的上升沿 到来。
在一种可能的实现方式中，在所述根据所述采样数据进行正交解调之前，所述方法还包括：缓存所述行扫描周期内得到的所述采样数据；在所述行扫描周期结束后，根据所述采样数据生成所述正弦信号和所述余弦信号。
在一种可能的实现方式中，不同的所述行扫描周期内的所述采样数据对应的采样点数量相同或者不同。
还可以采用数据缓存法对每个行扫描周期内的触控检测信号进行处理。例如，先缓存行扫描周期内的触控检测信号的采样数据，从而在该行扫描周期结束之后，根据在该行扫描周期内能够获得的采样数据，对检测信号进行解调，得到解调结果，以使该解调结果与该行扫描周期完全同步。
在一种可能的实现方式中，所述方法还包括：根据所述行扫描周期内的所述解调结果和与其相邻的行扫描周期内的所述解调结果，采用相关双采样的方式，确定触控检测的结果。
对相邻两个行扫描周期内采集到的触控检测信号，进行相关双采样，可以使触控检测的结果具有更高的信噪比。
在一种可能的实现方式中，所述方法还包括：对所述行同步信号或者所述检测信号进行采样，得到采样数据；对所述采样数据进行插值和拟合，以提升所述采样数据的采样率；根据提升采样率之后的所述采样数据，确定所述行扫描周期内的所述行同步信号的上升沿的时刻，其中，提升采样率之后的所述采样数据的相邻两个采样点之间的时间间隔小于或者等于所述行扫描周期在时域上的抖动值。
可以利用采样电路对行同步信号或者触控检测信号进行采样，从而确定行同步信号的上升沿的时刻。为此，需要增加采样电路的采样点数，以匹配行扫描周期的抖动值，才能够精准地采集到行同步信号的上升沿的时刻。
第三方面，提供了一种电子设备，包括上述第一方面或者第一方面的任意可能的实现方式中的触控芯片。
附图说明
图1是屏幕模组的示意图。
图2是行同步信号、像素数据、显示层噪声与触控检测信号之间的关系的示意图。
图3是行同步信号的抖动对触控检测信号的影响的示意图。
图4是理想情况下行同步信号、采样数据和正弦信号的时序的示意图。
图5是行扫描周期不稳定时行同步信号、采样数据和正弦信号的时序的示意图。
图6是本申请实施例的触控芯片的示意性框图。
图7是本申请实施例的相位重置法的示意图。
图8是本申请实施例的相位暂停法的示意图。
图9是本申请实施例的数据缓存法的示意图。
图10是本申请实施例的相关双采样的示意图。
图11是本申请实施例的触控检测信号的处理方法的示意性流程图。
具体实施方式
下面将结合附图，对本申请中的技术方案进行描述。
如今，电子设备的屏幕被涉及的越来越薄，以减小电子设备的厚度，或者在相同厚度下使电子设备中有更多空间容纳其他内部器件。其中，屏幕的类型从液晶显示器(Liquid Crystal Display，LCD)到有机发光二极管(Organic Light Emitting Diode，OLED)显示器的转换就是一种典型趋势。然而，OLED屏幕变薄以后，屏幕的触控层中的触控电极的基础电容变大，并且使得从显示层中耦合至触控层的噪声变大，直接影响了触控检测的性能和灵敏度。
图1所示为屏幕模组的示意图，屏幕模组中的触控层和显示层通常是两套独立且分离的系统，理论上，它们相互之间可能不存在干扰或者干扰较小。但是，由于如今的屏幕越来越薄，触控层中的触控电极相对于系统地的距离更近，使得触控电极对系统地的自电容从以前的100pF左右提升至现在的500pF左右，导致触控层和显示层之间的相互影响无法被忽略。
如图1所示，显示驱动芯片产生的信号传输至屏幕模组的显示层，并通过走线的寄生电容C D耦合到触控层和显示层的系统地，再通过触控层中的触控电极的对地电容C sg和C dg耦合到触控层，从而使触控层上形成显示层噪声，并最终耦合到触控芯片，从而影响了触控检测的性能。
显示驱动芯片产生行同步信号(记作Hsync信号)作为时钟，更新显示层的每行像素的像素数据(或称为显示数据)。由于触控层的触控电极的基础电容变大，每行像素的像素数据刷新时，输入显示层的信号会从触控层和 显示层之间的公共阴极耦合到触控层的触控电极，并最终影响触控检测。也就是说，从显示层耦合到触控层的显示层噪声与显示层的Hsync信号之间同步。
图2示出了行同步信号、像素数据、显示层噪声以及触控触控检测信号(以下也简称为检测信号)之间的关系。如图2所示，显示驱动芯片以Hsync信号为时钟更新显示层的各行像素的像素数据(或称为显示数据)，而显示层噪声产生于像素数据刷新时，因此显示层噪声与Hsync信号同步。为了解决显示层噪声对触控层的触控检测造成的影响，可以使触控检测时输出的触控打码信号(也简称打码信号或者驱动信号)与Hsync信号之间同步，最终使得到的检测信号也与Hsync信号之间同步，即保持恒定的相位差，从而在一定程度上削弱显示层噪声对触控检测的干扰。例如图2所示，在行扫描周期内的低噪声时段获取检测信号，该检测信号与Hsync信号之间同步。基于该检测信号，就可以获得用户的触摸信息例如触摸位置、触摸压力等。
应理解，本申请实施例中所述的触控打码信号，指触控芯片在触控检测期间输出的打码信号，包括输入至触控层的打码信号；也包括触控检测期间输出的用于对触控检测中其他电路进行控制的控制信号，例如触发采样电路对检测信号进行采样的触发信号等。
显示驱动芯片通过内部RC振荡电路产生Hsync信号。由于RC振荡电路的时钟本身精度较差且温漂较大，因此产生的Hsync信号存在抖动，具体表现为Hsync信号的行扫描周期可能发生微弱的变化，因此耦合到触控层中的显示层噪声也存在抖动。当以某个Hsync信号的边沿触发触控芯片中的采样电路采集检测信号时，行扫描周期的抖动会在时域上从一个行扫描周期传递到下一个行扫描周期并进行叠加。连续采样的时间越长，采集到的检测信号的抖动就越大。
从显示层耦合到触控层中的显示层噪声变大时，检测信号仍需要有一定的信噪比，这时可以将触控芯片输出的打码信号(也称驱动信号)与Hsync信号同步，从而在一定程度上消除显示层噪声对触控检测的干扰。
但是，当显示层的Hsync信号的行扫描周期不稳定时，触控芯片采集的检测信号也就不稳定，对检测信号进行采样和解调后的解调结果也就不稳定，具体表现为解调结果在一定范围内抖动。这样，行扫描周期的不稳定就会给触控检测带来额外的噪声，影响触控检测的结果。
例如图3所示，Hsync信号的一个行同步扫描周期在理想情况下是稳定的，不会发生抖动。假设理想情况下的行扫描周期均稳定在10us，实际应用中的行扫描周期的抖动值为±10ns，如图3的第一行所示。触控芯片中的采样电路以某个Hsync信号的上升沿作为触发，连续采样1ms的检测信号，如图3的第二行所示。在理想情况下，行扫描周期是稳定的，采样电路总共采样了100个周期的检测信号，如图3的第三行所示。但是由于行扫描周期在实际应用中存在抖动，因此采样电路实际采样的周期数为99.9～100.1。最后一个行扫描周期相对于采样触发时刻，在时域上的抖动高达±10ns×100＝±1us。这样，对于2MHz的采样频率而言，最后一个周期内的检测信号存在1us/(1/2MHz)＝±2个采样点的误差。由于行扫描周期的不稳定，可能导致对检测信号少采样或者多采样两个采样点的数据，分别如图3的第4行和第5行所示。
通常，在触控检测中，会将采样电路采集到的采样数据先经过正交解调(也称IQ解调或正交IQ解调)，从而得到检测信号的解调结果，之后再发送给处理器进行触摸坐标的计算。图3的最后一行所示是用于对采样数据进行解调的正弦信号(Sin信号)，由于本申请实施例对余弦信号(Cos信号)和正弦信号的处理相同，以下均以正弦信号为例进行描述。在这种情况下，检测信号在时域上存在抖动而用于正交解调的正弦信号在时域上不存在抖动，因此在进行正交解调的过程中，当检测信号与正弦信号和余弦信号点乘后，导致解调结果也发生抖动，具体体现为解调得到的信号幅值的抖动。对于检测信号中的有效信号而言，这种解调结果的抖动就是叠加在有效信号上的噪声。图3中忽略了电路系统的底噪，且假设没有外界物体触摸触控电极而改变检测信号的幅值。在不考虑行扫描周期的抖动时，解调结果只有一个；在考虑行扫描周期的抖动时，解调结果就会在一定范围内抖动，对于检测信号中的有效信号而言，解调结果的抖动就是噪声。
图4和图5分别示出了行扫描周期不存在抖动和存在抖动时对正交解调的影响，其中仅示出用于正交解调的正弦信号。如图4所示，当行扫描周期不存在抖动时，对每个行扫描周期内的检测信号进行采样时的采样点数固定不变，由于用于正交解调的正弦信号和余弦信号是在每段采样时间内按照固定频率产生的，相对于检测信号而言在时域上没有抖动，那么进行解调后得到的解调结果也是稳定的。如图5所示，当行扫描周期存在抖动时，导致每 个行扫描周期内的检测信号进行采样时的采样点数不断变化，由于正交解调的正弦信号和余弦信号是在每段采样长度中按照固定频率产生，如图5中的Sin0信号，由于行扫描周期的抖动，某个行扫描周期的采样数据的Sin0信号可能对应到其他行扫描周期的检测信号，这就给解调结果带来误差。而且，由于行扫描周期是随机抖动，Sin0信号对应到其他行扫描周期的检测信号的时刻和相位不同，导致解调结果的误差不断变化。这样，对检测信号进行解调后得到的解调结果中的噪声就会变大。
为了降低显示层的Hsync信号对触控检测的影响，本申请提出了一种处理检测信号的方案，能够得到如图5中的Sin0’信号所示的由于正交解调的正弦信号和余弦信号，从而降低显示层的Hsync信号对触控检测结果的影响，提高触控检测系统的信噪比。下面结合图6至图11进行详细描述。
图6是本申请实施例的触控芯片的示意性框图。如图6所示，触控芯片600包括驱动电路610、检测电路620、采样电路630和解调电路640。
其中，驱动电路610用于根据屏幕的显示层的行同步信号的行扫描周期，向屏幕的触控层输出打码信号。
检测电路620，用于接收触控层输出的检测信号。
采样电路630，用于对该检测信号进行采样，得到采样数据。
解调电路640，用于根据该采样数据进行正交解调，得到该检测信号的解调结果。
这里所述的解调结果，例如指对该检测信号进行解调后得到的检测信号的信号幅度。
其中，该行扫描周期是变化的，该行扫描周期内的用于进行正交解调的正弦信号和余弦信号的0°相位的时刻，与该行扫描周期的起始时刻相同。
其中，每个行扫描周期的起始时刻，例如可以是该行扫描周期内的行同步信号的上升沿的时刻，或者是其上一个行扫描周期内的行同步信号的下降沿的时刻。
每段采样时间内对应的各个行扫描周期中，均可以基于上述方式对检测信号进行处理，最终得到该段采样时间内的用于正交解调的正弦信号和余弦信号，并基于该正弦信号和余弦信号对检测信号进行正交解调，从而得到该段采样时间内的解调结果。
应理解，在触控检测期间，驱动电路610输出打码信号以及检测电路620 接收相应的检测信号可以是同步进行的。通常，在驱动电路610输出打码信号的同时，检测电路620接收从触控层输出的检测信号。该检测信号中携带用户的触摸信息，例如用户触摸引起的触控电极的电容变化量等。对该检测信号进行后续处理后，就可以得到用户的触摸信息。
还应理解，这里所述的行扫描周期是变化的，是指该行扫描周期或者行扫描信号在时域上存在抖动。也就是说，显示层的行同步信号的输出在时域上是不稳定的，或者行扫描周期在时域上是不稳定的。例如，理想情况下，行扫描周期在时域上是稳定的，每个行扫描周期的长度都是10us；而当行扫描周期在时域上不稳定时，其长度为10us±10ns，存在10ns范围内的抖动。
当行扫描周期变化时，不同的行扫描周期内的采样数据对应的采样点数量可能相同，也可能不同。
可见，当显示层的行同步信号的行扫描周期不稳定时，对检测信号的采样数据进行解调时，通过使每个行扫描周期内的用于进行正交解调的正余弦信号的0°相位的时刻，与该行扫描周期内的行同步信号的上升沿的时刻相同，从而使正交解调后得到的解调结果也是稳定的，降低了显示层的行同步信号在时域上的抖动对触控层的触控检测的噪声影响，提高了触控检测系统的信噪比。
其中，得到的行扫描周期内的正弦信号和余弦信号的相位可能大于、等于或者小于特定值。
通常，该特定值为360°；在一些实现方式中，例如采用相关双采样的方式处理检测信号时，该特定值可以是180°。
以下，所述的行扫描周期，均以相邻两个行同步信号的脉冲的上升沿之间的时段作为一个行扫描周期为例，对本申请实施例进行描述，因此，每个行扫描周期内的用于进行正交解调的正弦信号和余弦信号的0°相位时刻，与每个行扫描周期内的行同步信号的上升沿的时刻相同。但应理解，当以相邻两个行同步信号的脉冲的下降沿之间的时段作为一个行扫描周期时，每个行扫描周期内的用于进行正交解调的正弦信号和余弦信号的0°相位的时刻，与其上一个行扫描周期内的行同步信号的下降沿的时刻相同。本申请实施例对如何划分行扫描周期不作限定，采样电路630从行扫描周期的起始时刻开始对该行扫描周期内的检测信号进行采样。
本申请提供三种检测信号的处理方式，下面结合图7至图9分别进行描 述。以下，方式1也可以称为相位重置法，方式2也可以称为相位暂停法，方式3也可以称为数据缓存法。
其中，在方式1和方式2中，触控芯片600还包括相位计数器。该相位计数器用于：在行扫描周期内的行同步信号的上升沿的时刻到来时，进行重置，以从0°相位开始记录相位信息。这时，解调电路640具体用于：根据重置后的相位计数器记录的相位信息，生成正弦信号和余弦信号。
应理解，所述的记录相位信息，对相位计数器而言，就是进行计数，例如以1为单位从0开始依次计数，即0、1、2、3……。解调电路640以相位计数器记录的数值为相位相关变量产生用于正交解调的正弦信号和余弦信号。
方式1
相位计数器在当前行扫描周期内记录的相位达到特定值时，基于该特定值继续记录相位信息，直至下一个行扫描周期内的行同步信号的上升沿的时刻到来；和/或，相位计数器在下一个行扫描周期内的行同步信号的上升沿到来时，若所记录的相位未达到所述特定值，则进行重置。
以该特定值为360°为例，如图7所示，T0为理想情况下的行扫描周期，行扫描周期在时域上没有抖动，行扫描周期的长度和频率稳定。T1、T2和T3为实际应用中的行扫描周期，由于行扫描周期在时域上存在抖动，导致每个行扫描周期的长度略有差异。图7中仅以Sin信号为例，图7中的相位计数器为Sin信号的相位计数器，且假设记录相位的步长为1°。在理想情况下，每个行扫描周期的行同步信号的上升沿到来时刻，Sin信号的相位计数器正好达到360°并从0°起重新开始记录相位，如图7中的相位计数器0和Sin0信号所示。而实际应用中，如图7中的相位计数器1和Sin 1信号所示，包括两种情况：
(1)、行同步信号的上升沿提前到来。
此时，相位计数器1记录的当前行扫描周期内的Sin 1信号的相位值还未达到360°。相位计数器1在下一个行扫描周期的行同步信号的上升沿到来时刻不再继续记录相位，而是重置后从1°开始重新记录下一个行扫描内的Sin 1信号的相位。
如图7所示，相位计数器1记录周期T1内的Sin 1信号的相位，并且，在周期T2的行同步信号的上升沿到来时刻，相位计数器1所记录的相位等 于358°，未到达360°。这时，相位计数器1不会接着358°继续记录相位，而是重置，并从0°起开始记录周期T2的Sin 1信号的相位。
(2)、行同步信号的上升沿滞后到来。
此时，相位计数器1记录的当前行扫描周期内的Sin 1信号的相位值达到360°时，下一个行扫描周期的行同步信号的上升沿的时刻还没有到来。相位计数器1接着360°继续记录当前行扫描周期内的Sin 1信号的相位并且超过360°，直至下一个行扫描周期的行同步信号的上升沿的时刻到来时重置，以从0°开始记录下一个行扫描周期的Sin 1信号的相位。
如图7所示，相位计数器1记录周期T2内的Sin 1信号的相位，并且，在记录的相位达到360°时，周期T3的行同步信号的上升沿的时刻还没有到来。这时，相位计数器1接着360°继续记录周期T2内的Sin 1信号的相位。当相位计数器1记录的相位达到362°时，周期T3的行同步信号的上升沿的时刻到来，这时相位计数器1重置，并从0°起开始记录周期T3的Sin 1信号的相位。
方式2
当前行扫描周期内记录的相位达到该特定值时，相位计数器暂停记录相位信息，直至下一个行扫描周期的行同步信号的上升沿的时刻到来；和/或，相位计数器在下一个行扫描周期内的行同步信号的上升沿到来时，若所记录的相位未达到该特定值，则进行重置。
以该特定值为360°为例，如图8所示，T0为理想情况下的行扫描周期，行扫描周期在时域上没有抖动，行扫描周期的长度和频率稳定。T1、T2和T3为实际应用中的行扫描周期，由于行扫描周期在时域上存在抖动，导致每个行扫描周期的长度略有差异。在芯片设计中，解调电路为硬件电路，且通常由查表法产生用于正交解调的Sin信号和Cos信号，图8中仅以Sin信号为例，图8中的相位计数器为Sin信号的相位计数器，且假设记录相位的步长为1°。在理想情况下，每个行扫描周期的行同步信号的上升沿到来时刻，Sin信号的相位计数器正好达到360°并从0°起重新开始记录相位，如图8中的相位计数器0和Sin0信号所示。而实际应用中，如图8中的相位计数器2和Sin 2信号所示，包括两种情况：
(1)、行同步信号的上升沿提前到来。
此时，相位计数器2记录的当前行扫描周期内的Sin 2信号的相位值还 未达到360°。相位计数器2在下一个行扫描周期的行同步信号的上升沿到来时刻不再继续记录相位，而是重置后从0°开始重新记录下一个行扫描内的Sin 2的相位。
如图8所示，相位计数器2记录周期T1内的Sin 2信号的相位，并且，在周期T2的行同步信号的上升沿到来时刻，相位计数器2所记录的相位等于358°，未到达360°。这时，相位计数器2不会接着358°继续记录相位，而是重置，并从0°起开始记录周期T2的Sin 2信号的相位。
(2)、行同步信号的上升沿滞后到来。
此时，相位计数器2记录的当前行扫描周期内的Sin 2信号的相位值达到360°时，下一个行扫描周期的行同步信号的上升沿的时刻还没有到来。相位计数器2暂停记录当前行扫描周期内的Sin 2信号的相位并保持Sin 2信号的相位恒定为360°，直至下一个行扫描周期的行同步信号的上升沿的时刻到来时重置，以从0°开始记录下一个行扫描周期的Sin 2信号的相位。
如图8所示，相位计数器2记录周期T2内的Sin 2信号的相位，并且，在记录的相位达到360°时，周期T3的行同步信号的上升沿的时刻还没有到来。这时，相位计数器2暂停记录相位并保持周期T2内的Sin 2信号的相位为360°。当周期T3的行同步信号的上升沿的时刻到来，这时相位计数器2重置，并从0°起开始记录周期T3的Sin 2信号的相位。
方式1和方式2的核心思想是相似的，都是在行同步信号的上升沿的时刻重置正弦信号和余弦信号的相位，且对于行扫描周期的抖动造成上升沿提前到来的处理方式一致，即直接重置相位计数器以开始下一轮的相位计数。方式1和方式2区别在于对行同步信号的上升沿的时刻滞后到来的处理方式，方式1是使相位计数器在360°的基础上继续记录相位直至下一个行扫描周期的行同步信号的上升沿到来，例如图7中的周期T2内的Sin 1信号的相位为362°；方式2是使相位计数器到360°时保持相位不变直至下一个行扫描周期的行同步信号的上升沿到来，例如图8中的周期T2内的Sin 1信号的相位为360°。
方式2和方式1只需要对相位计数器的相位计数的方式进行调整，无需增加额外的电路结构，就可以避免行扫描周期的抖动对解调结果的影响，提高触控检测系统的信噪比。
方式3
触控芯片600还包括缓存电路，用于：在解调电路640根据采样数据进行正交解调之前，缓存行扫描周期内得到的该采样数据。其中，解调电路640具体用于：在该行扫描周期结束后，根据该采样数据生成正弦信号和余弦信号。
在方式3中，在对每个行扫描周期内的采样数据进行解调时，只需要产生和该行扫描周期内等采样点数量的正弦信号和余弦信号即可。也就是说，每个行扫描周期内有多少个采样点，产生该行扫描周期对应的正弦信号和余弦信号时也基于相同的该采样点数。下面结合图9的示例具体进行说明。
采样电路630例如可以是ADC电路。如图9所示，以正弦信号为例，在采样电路630开始采样时，先缓存每个采样点，此时不开始生成用于正交解调的Sin 3信号。直到采样电路630对每个行扫描周期内的检测信号采集完成后，生成与每个行扫描周期内等采样点的Sin 3信号，再根据每个行扫描周期对应的Sin 3信号和缓存的该行扫描周期内的检测信号进行正交解调。
如图9所示，采样电路630对周期T1内的检测信号采集完成后，周期T1内包含6个采样点，则解调电路640生成包含6个采样点、初始相位为0°的Sin 3信号；采样电路630对周期T2内的检测信号采集完成后，周期T2内包含7个采样点，则解调电路640生成包含7个采样点、初始相位为0°的Sin 3信号；采样电路630对周期T3内的检测信号采集完成后，周期T3内包含8个采样点，则解调电路640生成包含8个采样点、初始相位为0°的Sin 3信号。图9仅示出了采样时间内的周期T1、周期T2和周期T3，之后的其他周期内按照类似的方式，得到对应的用于对相应周期内的检测信号进行正交解调的Sin 3信号。最后，根据采样时间内得到的Sin 3信号，对该段采样时间内的检测信号进行正交解调，从而得到该段采样时间内的解调结果。
方式3可以使用于正交解调的正弦信号和余弦信号，与行同步信号之间完全同步，彻底消除行扫描周期在时域和频域上的抖动对解调结果的影响。相较于方式1和方式2，方式3是消除抖动影响的效果最好的方式。但是，方式3中需要提前缓存至少一个行扫描周期的采样点，并且要滞后至少一个行扫描周期才能输出解调结果。
上面的方式1至方式3中均以360°为例。但本申请实施例也可以采用相关双采样的方式，对检测信号进行处理。这时，相邻两个行扫描周期对应 的该特定值分别为180°和360°。
在一种实现方式中，触控芯片600还包括处理电路，用于：根据该行扫描周期内的解调结果和与其相邻的行扫描周期内的解调结果，采用相关双采样的方式，确定触控检测的结果。
采用相关双采样的方式对检测信号进行处理，可以进一步消除解调结果中的噪声，提高触控检测系统的信噪比。
例如图10所示，当行扫描周期稳定时，参考相位计数器4和Sin 4信号；当行扫描周期不稳定时，参考相位计数器5和Sin 5信号。以方式1为例，在进行相关双采样时，周期T2的行扫描信号的上升沿到来时相位计数器5在周期T1记录的相位为178°时，此时相位计数器5重置并从180°开始记录周期T2内的正弦信号的相位；相位计数器5在周期T2记录的相位为达到360°时，接着360°继续记录相位，直到行扫描信号的上升沿到来时重置并从0°开始记录周期T3内的Sin 5信号的相位。
本申请实施例还提供了一种判断行扫描信号的上升沿的方法。采样电路620用于：对行同步信号或者检测信号进行采样，得到采样数据；对该采样数据进行插值和拟合，以提升所述采样数据的采样率；根据提升采样率之后的所述采样数据，确定该行扫描周期内的行同步信号的上升沿的时刻。
其中，提升采样率之后的该采样数据的相邻两个采样点之间的时间间隔小于或者等于该行扫描周期在时域上的抖动值。
通常，采样电路620对检测信号进行采样时的采样频率不会太高，为了可以利用采样电路620判断行同步信号的上升沿的位置，可以将采样电路620采集到的数据通过插值、拟合等方式提升采样率后再进行判断。
例如，采样电路620的采样频率为2MHz，使用其采集的原始数据进行上升沿判断的误差为一个采样周期，即0.5us，该时间远超大部分屏幕的行扫描周期的抖动值，例如±10ns的抖动值。通过插值，给每两个相邻采样点间之间插值49个采样点，则行同步信号的上升沿的判断误差变为10ns，保证了上升沿判断的精度。
这里的插值方法包括但不限于线性、非线性插值以及二者组合的方式；拟合方式包括但不限于线性拟合、非线性拟合以及二者组合的方式。
表一示出了采用本申请实施例的检测信号的处理方式时得到的触控检测结果。假设触控检测的时间为500us，触控检测为自容检测。如表一所示， 不采用本申请的方案时，在低噪画面、中噪画面、高噪画面和动态视频中，检测结果的信噪比(Signal Noise Ratio，SNR)分别为7.86、6.40、2.82和6.11；采用本申请的方案时，在低噪画面、中噪画面、高噪画面和动态视频中，检测结果的信噪比分别为7.86、7.14、3.70和6.32。因此，采用本申请实施例的方案，可以在低噪画面、中噪画面、高噪画面和动态视频中分别将触控检测的性能提升至原来的1.00、1.12和1.03倍。
表一
Figure PCTCN2020118360-appb-000001
从表一可以看出，采用本申请的信号处理方式，能够有效降低行扫描周期的抖动对检测结果的影响，提高触控检测系统的信噪比。其中，对于表一中测试的电子设备的屏幕而言，显示层噪声越大的画面，行扫描周期的抖动越严重，采用本申请的信号处理方式后对触控检测系统的信噪比提升的越明显，可以提升0-31％。
表二示出了打码时间对触控检测的结果的影响。假设测试画面为高噪画面，触控检测为自容检测。从表二可以看出，在采用本申请的方案后，检测 结果的信噪比有了明显提升。并且，随着打码时间和检测时间的增加，行扫描周期的抖动越严重，采用本申请的方案后对检测结果的信噪比提升得越明显，尤其当打码时间为250us、500us和1ms时，可以分别将信噪比提升至原来的101.2％、143.0％和332.4％。
表二
Figure PCTCN2020118360-appb-000002
可见，本申请从信号解调的角度消除或者削弱了行扫描周期的抖动对检测结果的影响。行扫描周期抖动造成采样时间内靠后的行扫描周期在时域上左右抖动明显，导致后端数字解调出来的信号幅值在变化，这种变化的幅值对于有效信号而言就是噪声，即行扫描周期的抖动会给触控检测带来额外的噪声。而采用本申请的方案消除或者削弱了行扫描周期的抖动给触控检测系统造成的额外的噪声。
本申请还提供一种触控检测信号的处理方法。如图11所示，该方法1100可以由上述触控芯片600执行。该方法1100包括以下步骤中的部分或全部。
在步骤1110中，根据屏幕的显示层的行同步信号的行扫描周期，向所述屏幕的触控层输出打码信号，并接收所述触控层输出的检测信号。
在步骤1120中，对所述检测信号进行采样，得到采样数据。
在步骤1130中，根据所述采样数据进行正交解调，得到所述检测信号的解调结果，其中，所述行扫描周期是变化的，所述行扫描周期内的用于进行正交解调的正弦信号和余弦信号的0°相位的时刻，与所述行扫描周期内的所述行同步信号的上升沿的时刻相同。
当显示层的行同步信号的行扫描周期不稳定时，对触控检测信号的采样数据进行解调时，通过使每个行扫描周期内的用于进行正交解调的正余弦信号的0°相位的时刻，与该行扫描周期内的行同步信号的上升沿的时刻相同， 从而使正交解调后得到的解调结果也是稳定的，降低了显示层的行同步信号在时域上的抖动对触控层的触控检测的噪声影响，提高了触控检测系统的信噪比。
可选地，在一种实现方式中，所述方法还包括：在所述行扫描周期内的所述行同步信号的上升沿的时刻到来时，重置相位计数器，以使所述相位计数器从0°相位开始记录相位信息；根据重置后的所述相位计数器记录的相位信息，生成所述正弦信号和所述余弦信号。
可选地，在一种实现方式中，所述行扫描周期内的所述正弦信号和所述余弦信号的相位大于、等于或者小于特定值，所述特定值为180°或者360°。
可选地，在一种实现方式中，所述方法还包括：当所述相位计数器在所述行扫描周期内记录的相位达到所述特定值时，基于所述特定值继续记录相位信息，直至下一个行扫描周期内的所述行同步信号的上升沿的时刻到来。
可选地，在一种实现方式中，所述方法还包括：当所述相位计数器在所述行扫描周期内记录的相位达到所述特定值时，暂停记录相位信息，直至下一个行扫描周期的所述行同步信号的上升沿的时刻到来。
可选地，在一种实现方式中，所述方法还包括：在下一个行扫描周期内的所述行同步信号的上升沿到来时，若所述相位计数器所记录的相位未达到所述特定值，则重置所述相位计数器。
可选地，在一种实现方式中，在所述根据所述采样数据进行正交解调之前，所述方法还包括：缓存所述行扫描周期内得到的所述采样数据；在所述行扫描周期结束后，根据所述采样数据生成所述正弦信号和所述余弦信号。
可选地，在一种实现方式中，不同的所述行扫描周期内的所述采样数据对应的采样点数量相同或者不同。
可选地，在一种实现方式中，所述方法还包括：根据所述行扫描周期内的所述解调结果和与其相邻的行扫描周期内的所述解调结果，采用相关双采样的方式，确定触控检测的结果。
可选地，在一种实现方式中，所述方法还包括：对所述行同步信号或者所述检测信号进行采样，得到采样数据；对所述采样数据进行插值和拟合，以提升所述采样数据的采样率；根据提升采样率之后的所述采样数据，确定所述行扫描周期内的所述行同步信号的上升沿的时刻，其中，提升采样率之 后的所述采样数据的相邻两个采样点之间的时间间隔小于或者等于所述行扫描周期在时域上的抖动值。
应理解，该方法1100的具体描述可以参考前述针对触控芯片600的相关描述，为了简洁，这里不再赘述。
本申请实施例还提供了一种电子设备，该电子设备包括：屏幕；以及，上述本申请各种实施例中的触控芯片。
作为示例而非限定，本申请实施例中的电子设备可以为终端设备、手机、平板电脑、笔记本电脑、台式机电脑、游戏设备、车载电子设备或穿戴式智能设备等便携式或移动计算设备，以及电子数据库、汽车、银行自动柜员机(Automated Teller Machine，ATM)等其他电子设备。该穿戴式智能设备包括功能全、尺寸大、可不依赖智能手机实现完整或部分的功能，例如：智能手表或智能眼镜等，以及只专注于某一类应用功能，需要和其它设备如智能手机配合使用，如各类进行体征监测的智能手环、智能首饰等设备。
需要说明的是，在不冲突的前提下，本申请描述的各个实施例和/或各个实施例中的技术特征可以任意的相互组合，组合之后得到的技术方案也应落入本申请的保护范围。
应理解，本申请实施例中的具体的例子只是为了帮助本领域技术人员更好地理解本申请实施例，而非限制本申请实施例的范围，本领域技术人员可以在上述实施例的基础上进行各种改进和变形，而这些改进或者变形均落在本申请的保护范围内。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (23)

  1. 一种触控芯片，其特征在于，包括：
    驱动电路，用于根据屏幕的显示层的行同步信号的行扫描周期，向所述屏幕的触控层输出打码信号；
    检测电路，用于接收所述触控层输出的检测信号；
    采样电路，用于对所述检测信号进行采样，得到采样数据；以及，
    解调电路，用于根据所述采样数据进行正交解调，得到所述检测信号的解调结果，其中，所述行扫描周期是变化的，所述行扫描周期内的用于进行正交解调的正弦信号和余弦信号的0°相位的时刻，与所述行扫描周期的起始时刻相同。
  2. 根据权利要求1所述的触控芯片，其特征在于，所述行扫描周期的起始时刻为所述行扫描周期内的所述行同步信号的上升沿的时刻。
  3. 根据权利要求1或2所述的触控芯片，其特征在于，所述触控芯片还包括相位计数器，用于：
    在所述行扫描周期内的所述行同步信号的上升沿的时刻到来时，进行重置，以从0°相位开始记录相位信息；
    其中，所述解调电路还用于：
    根据重置后的所述相位计数器记录的相位信息，生成所述正弦信号和所述余弦信号。
  4. 根据权利要求3所述的触控芯片，其特征在于，所述行扫描周期内的所述正弦信号和所述余弦信号的相位大于、等于或者小于特定值，所述特定值为180°或者360°。
  5. 根据权利要求4所述的触控芯片，其特征在于，所述相位计数器还用于：
    当所述行扫描周期内记录的相位达到所述特定值时，基于所述特定值继续记录相位信息，直至下一个行扫描周期内的所述行同步信号的上升沿的时刻到来。
  6. 根据权利要求4或5所述的触控芯片，其特征在于，所述相位计数器还用于：
    当所述行扫描周期内记录的相位达到所述特定值时，暂停记录相位信息，直至下一个行扫描周期的所述行同步信号的上升沿的时刻到来。
  7. 根据权利要求4至6中任一项所述的触控芯片，其特征在于，所述相位计数器还用于：
    在下一个行扫描周期内的所述行同步信号的上升沿到来时，若所记录的相位未达到所述特定值，则进行重置。
  8. 根据权利要求1或2所述的触控芯片，其特征在于，所述触控芯片还包括缓存电路，用于：
    在所述解调电路根据所述采样数据进行正交解调之前，缓存所述行扫描周期内得到的所述采样数据；
    其中，所述解调电路还用于：
    在所述行扫描周期结束后，根据所述采样数据生成所述正弦信号和所述余弦信号。
  9. 根据权利要求8所述的触控芯片，其特征在于，不同的所述行扫描周期内的所述采样数据对应的采样点数量相同或者不同。
  10. 根据权利要求1至9中任一项所述的触控芯片，其特征在于，还包括处理电路，用于：
    根据所述行扫描周期内的所述解调结果和与其相邻的行扫描周期内的所述解调结果，采用相关双采样的方式，确定触控检测的结果。
  11. 根据权利要求1至10中任一项所述的触控芯片，其特征在于，所述采样电路还用于：
    对所述行同步信号或者所述检测信号进行采样，得到采样数据；
    对所述采样数据进行插值和拟合，以提升所述采样数据的采样率；
    根据提升采样率之后的所述采样数据，确定所述行扫描周期内的所述行同步信号的上升沿的时刻，其中，提升采样率之后的所述采样数据的相邻两个采样点之间的时间间隔小于或者等于所述行扫描周期在时域上的抖动值。
  12. 一种触控检测信号的处理方法，其特征在于，包括：
    根据屏幕的显示层的行同步信号的行扫描周期，向所述屏幕的触控层输出打码信号，并接收所述触控层输出的检测信号；
    对所述检测信号进行采样，得到采样数据；
    根据所述采样数据进行正交解调，得到所述检测信号的解调结果，其中，所述行扫描周期是变化的，所述行扫描周期内的用于进行正交解调的正弦信号和余弦信号的0°相位的时刻，与所述行扫描周期的起始时刻相同。
  13. 根据权利要求12所述的方法，其特征在于，所述行扫描周期的起始时刻为所述行扫描周期内的所述行同步信号的上升沿的时刻。
  14. 根据权利要求12或13所述的方法，其特征在于，所述方法还包括：
    在所述行扫描周期内的所述行同步信号的上升沿的时刻到来时，重置相位计数器，以使所述相位计数器从0°相位开始记录相位信息；
    根据重置后的所述相位计数器记录的相位信息，生成所述正弦信号和所述余弦信号。
  15. 根据权利要求14所述的方法，其特征在于，所述行扫描周期内的所述正弦信号和所述余弦信号的相位大于、等于或者小于特定值，所述特定值为180°或者360°。
  16. 根据权利要求15所述的方法，其特征在于，所述方法还包括：
    当所述相位计数器在所述行扫描周期内记录的相位达到所述特定值时，基于所述特定值继续记录相位信息，直至下一个行扫描周期内的所述行同步信号的上升沿的时刻到来。
  17. 根据权利要求15或16所述的方法，其特征在于，所述方法还包括：
    当所述相位计数器在所述行扫描周期内记录的相位达到所述特定值时，暂停记录相位信息，直至下一个行扫描周期的所述行同步信号的上升沿的时刻到来。
  18. 根据权利要求15至17中任一项所述的方法，其特征在于，所述方法还包括：
    在下一个行扫描周期内的所述行同步信号的上升沿到来时，若所述相位计数器所记录的相位未达到所述特定值，则重置所述相位计数器。
  19. 根据权利要求12所述的方法，其特征在于，在所述根据所述采样数据进行正交解调之前，所述方法还包括：
    缓存所述行扫描周期内得到的所述采样数据；
    在所述行扫描周期结束后，根据所述采样数据生成所述正弦信号和所述余弦信号。
  20. 根据权利要求19所述的方法，其特征在于，不同的所述行扫描周期内的所述采样数据对应的采样点数量相同或者不同。
  21. 根据权利要求12至20中任一项所述的方法，其特征在于，所述方法还包括：
    根据所述行扫描周期内的所述解调结果和与其相邻的行扫描周期内的所述解调结果，采用相关双采样的方式，确定触控检测的结果。
  22. 根据权利要求12至21中任一项所述的方法，其特征在于，所述方法还包括：
    对所述行同步信号或者所述检测信号进行采样，得到采样数据；
    对所述采样数据进行插值和拟合，以提升所述采样数据的采样率；
    根据提升采样率之后的所述采样数据，确定所述行扫描周期内的所述行同步信号的上升沿的时刻，其中，提升采样率之后的所述采样数据的相邻两个采样点之间的时间间隔小于或者等于所述行扫描周期在时域上的抖动值。
  23. 一种电子设备，其特征在于，包括上述权利要求1至11中任一项所述的触控芯片。
PCT/CN2020/118360 2020-09-28 2020-09-28 触控芯片、触控检测信号的处理方法和电子设备 WO2022061875A1 (zh)

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