Detection circuit of touch screen and terminal equipment

Abstract

The embodiment of the invention provides a detection circuit of a touch screen and terminal equipment, which can obtain a first digital signal by processing a touch signal, then amplify a noise signal to obtain an amplified noise signal, convert the amplified noise signal into a second digital signal, and send the second digital signal to the terminal equipment. Whether the touch signal is valid or not is judged by combining the first digital signal and the second digital signal through the control module, real touch operation and false touch signals caused by noise can be effectively distinguished, the terminal equipment with the touch screen can be normally used under the condition that the power supply environment is severe, false alarm points are reduced, and the user experience is improved. The reliability of the touch screen is improved, and then the user experience is improved.

Description

Technical Field

[0001] The present invention relates to the field of electronic equipment, and in particular to a detection circuit and terminal equipment of a touch screen. Background Art

[0002] Most touch screens on the market are mutual capacitance touch screens that support multi-touch. They are composed of two layers of cross planes composed of X and Y sensing channels. The intersections form a sensing point matrix. When a finger touches the screen, the capacitance value of the electrode at the corresponding position will change. Based on this, the precise coordinates can be obtained and reported to the application layer to trigger related functions. The transient pulse interference generated by the opening and closing of power switches, relays and inductive loads on the power grid can be easily transmitted to the touch screen sensing layer through the power topology network, resulting in abnormal X and Y channel sensing values, causing false alarm points, false triggering of icons and product function disorders. Summary of the invention

[0003] In view of the above problems, embodiments of the present invention are proposed to provide a detection circuit and terminal device for a touch screen that overcome the above problems or at least partially solve the above problems.

[0004] In order to solve the above problem, an embodiment of the present invention discloses a detection circuit of a touch screen, wherein the detection circuit comprises:

[0005] An acquisition module, used for acquiring a touch signal of the touch screen;

[0006] an analog-to-digital conversion module, connected to the acquisition module, and configured to determine a first digital signal according to the touch signal;

[0007] An operational amplifier module, used to obtain a noise signal, amplify the noise signal, and obtain an amplified noise signal;

[0008] A first analog-to-digital converter, connected to the operational amplifier, and configured to convert the amplified noise signal into a second digital signal;

[0009] The control module is connected to the analog-to-digital conversion module and the first analog-to-digital converter, respectively, and is used to obtain the first digital signal and the second digital signal, and determine whether the touch signal is valid according to the first digital signal and the second digital signal.

[0010] Optionally, the control module is used to determine a first frequency corresponding to the first digital signal and a second frequency corresponding to the second digital signal, and judge whether the first frequency is consistent with the second frequency; if the first frequency is inconsistent with the second frequency, determine that the touch signal is valid.

[0011] Optionally, the control module is also used to determine the time domain signal and the total number of sampling points of the first digital signal if the first digital signal is a periodic signal, determine the frequency domain signal of the first digital signal based on the time domain signal and the total number of sampling points of the first digital signal, and determine the first frequency based on the frequency domain signal of the first digital signal.

[0012] Optionally, the control module is further used to determine a scale factor and a preset mother wavelet constant corresponding to the first digital signal if the first digital signal is a non-periodic signal; and determine the first frequency according to the scale factor and the preset mother wavelet constant.

[0013] Optionally, the control module is also used to determine a first envelope modulus value corresponding to the first digital signal and a second envelope modulus value corresponding to the second digital signal if the first frequency is consistent with the second frequency, and judge whether the first envelope modulus value is consistent with the second envelope modulus value; if the first envelope modulus value is consistent with the second envelope modulus value, filter out the touch signal.

[0014] Optionally, the analog-to-digital conversion module is further used to process the touch signal to obtain a processed touch signal, and convert the processed touch signal into the first digital signal.

[0015] Optionally, the analog-to-digital conversion module also includes an analog front-end module, which is used to perform baseline calibration on the touch signal, amplify the calibrated touch signal to obtain an amplified touch signal, and filter the amplified touch signal to obtain the processed touch signal.

[0016] Optionally, the analog-to-digital conversion module further includes a second analog-to-digital converter, and the second analog-to-digital converter is used to convert the processed touch signal into the first digital signal.

[0017] Optionally, the detection circuit further includes a power supply module, which is connected to the acquisition module and the operational amplifier module respectively, and is used to supply power to the acquisition module and the operational amplifier module.

[0018] Optionally, the power supply module includes an AC power supply, a DC conversion module, and a low voltage dropout linear regulator, and the DC conversion module is connected to the AC power supply and the low voltage dropout linear regulator respectively;

[0019] The DC conversion module is used to convert the AC power output by the AC power supply into DC power, and output the DC power to the low voltage drop linear regulator;

[0020] The low voltage drop linear regulator is used to convert the direct current into low voltage direct current and input it into the acquisition module and the operational amplifier module.

[0021] Optionally, the control module includes a controller, and the controller is used to determine that the touch signal is valid if the first frequency is inconsistent with the second frequency, perform point reporting processing on the touch signal, and execute an action corresponding to the touch signal.

[0022] The present invention also discloses a terminal device, which comprises the detection circuit of the touch screen and the touch screen as described in any one of the above items.

[0023] The present invention discloses a detection circuit for a touch screen, which can obtain a first digital signal by processing a touch signal, then amplify a noise signal to obtain an amplified noise signal, convert the amplified noise signal into a second digital signal, and determine whether the touch signal is valid by combining the first digital signal and the second digital signal through a control module. The circuit can effectively distinguish between a real touch operation and a false touch signal caused by noise, and can enable a terminal device with a touch screen to be used normally even in a poor power supply environment, avoiding interference from power supply noise, and preventing false alarm points. The circuit has high reliability, thereby improving user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A structural block diagram of a detection circuit of a touch screen provided by an embodiment of the present invention is shown;

[0025] Figure 2 A structural block diagram of another touch screen detection circuit provided by an embodiment of the present invention is shown;

[0026] Figure 3 A schematic diagram of a process for detecting a touch signal provided by an embodiment of the present invention is shown;

[0027] Figure 4 A structural block diagram of a terminal device provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] One of the core concepts of the embodiments of the present invention is that a first digital signal can be obtained by processing a touch signal, and then amplifying a noise signal to obtain an amplified noise signal, and the amplified noise signal is converted into a second digital signal. The control module combines the first digital signal and the second digital signal to determine whether the touch signal is valid, which can effectively distinguish between real touch operations and false touch signals caused by noise. Terminal equipment with a touch screen can be used normally even in a poor power supply environment, avoiding interference from power supply noise, and preventing false alarm points. The reliability is high, thereby improving the user experience.

[0030] Reference Figure 1 , shows a detection circuit 10 of a touch screen provided by an embodiment of the present invention, and the detection circuit may include:

[0031] The acquisition module 101 is used to acquire a touch signal of the touch screen;

[0032] The analog-to-digital conversion module 102 is connected to the acquisition module and is used to determine the first digital signal according to the touch signal;

[0033] The operational amplifier module 103 is used to obtain the noise signal and amplify the noise signal to obtain an amplified noise signal;

[0034] A first analog-to-digital converter 104, connected to the operational amplifier, for converting the amplified noise signal into a second digital signal;

[0035] The control module 105 is connected to the analog-to-digital conversion module and the first analog-to-digital converter, respectively, and is used to obtain the first digital signal and the second digital signal, and determine whether the touch signal is valid according to the first digital signal and the second digital signal.

[0036] In an embodiment of the present invention, the acquisition module 101 can acquire a touch signal of the touch screen. The touch signal refers to an analog signal generated on a receiving channel of the touch screen after the user's finger touches the screen. These signals may be caused by a change in capacitance, a change in resistance, or a change in other physical quantities. For example, in a capacitive touch screen, when a finger touches the screen, the capacitance value at the touch point will change, and the acquisition module 101 will sense this capacitance change and convert it into a corresponding electrical signal.

[0037] The analog-to-digital conversion module 102 is connected to the acquisition module 101, and its function is to convert the collected analog touch signal into a first digital signal. The analog-to-digital conversion can be achieved by sampling and quantizing the analog signal. In the sampling stage, the analog-to-digital conversion module samples the analog touch signal within a specific time interval to obtain a series of discrete sample points. Then, in the quantization stage, these sample points will be converted into digital values, and these digital values ​​constitute the first digital signal. For example, a common ADC may divide the amplitude range of the analog signal into multiple intervals, each interval corresponding to a digital code. In this way, the analog signal is converted into a digital signal, which is convenient for subsequent digital processing.

[0038] The operational amplifier module 103 is used to obtain a noise signal, which refers to a power grid noise signal. The operational amplifier is a high-gain electronic amplifier that can amplify weak noise signals. The operational amplifier has two input ports and one output port. By properly configuring external resistors and other components, its amplification factor can be set. For example, by selecting appropriate feedback resistors and input resistors, the noise signal can be amplified to an amplitude that is convenient for subsequent processing.

[0039] The first analog-to-digital converter 104 is connected to the operational amplifier, and converts the amplified noise signal into a second digital signal, which is similar to the process of the analog-to-digital conversion module 102 converting the touch signal into the first digital signal. By converting the noise signal into a digital signal through sampling and quantization, the control module can analyze and process the noise in a digital manner, and compare and operate with the first digital signal in the same digital domain.

[0040] The control module 105 is connected to the analog-to-digital conversion module 102 and the first analog-to-digital converter 104 respectively, and it can obtain the first digital signal and the second digital signal. The control module can be a microcontroller or other digital processing unit, which has the ability to process digital signals and can read and store digital signals transmitted from the analog-to-digital conversion module and the first analog-to-digital converter.

[0041] The control module 105 can determine whether the touch signal is valid based on the first digital signal and the second digital signal. Specifically, the first digital signal and the second digital signal can be compared, and whether the touch signal is an abnormal noise signal can be determined based on the comparison result to more accurately determine the validity of the touch signal.

[0042] The present invention discloses a detection circuit for a touch screen, which can obtain a first digital signal by processing a touch signal, then amplify a noise signal to obtain an amplified noise signal, convert the amplified noise signal into a second digital signal, and determine whether the touch signal is valid by combining the first digital signal and the second digital signal through a control module. The circuit can effectively distinguish between a real touch operation and a false touch signal caused by noise, and can enable a terminal device with a touch screen to be used normally even in a poor power supply environment, avoiding interference from power supply noise, and preventing false alarm points. The circuit has high reliability, thereby improving user experience.

[0043] In one embodiment of the present invention, the control module is used to determine a first frequency corresponding to the first digital signal and a second frequency corresponding to the second digital signal, and judge whether the first frequency is consistent with the second frequency. If the first frequency is inconsistent with the second frequency, it is determined that the touch signal is valid.

[0044] In an embodiment of the present invention, the control module 105 can perform frequency analysis on the first digital signal obtained from the analog-to-digital conversion module, and can use digital signal processing algorithms such as fast Fourier transform (FFT) to extract the frequency components of the first digital signal, thereby determining the first frequency. In touch screen application scenarios, the touch signal generated by a real touch operation often has a specific frequency characteristic. For example, when a finger touches the screen, due to the physical characteristics of the touch action and the response mechanism of the touch screen itself, a relatively stable and regular frequency component will be formed in the touch signal. This frequency is the first frequency.

[0045] Similarly, for the second digital signal obtained from the first analog-to-digital converter, the control module also uses corresponding digital signal processing means to analyze its frequency component, and then determine the second frequency.

[0046] When the control module determines that the first frequency is inconsistent with the second frequency, it can be determined that the touch signal is valid. This is because if the first frequency is different from the second frequency, it means that the change in the first digital signal currently detected is not caused by a noise signal, but comes from a real touch operation; through such a distinction based on frequency characteristics, the signal fluctuation caused by noise interference can be effectively distinguished from the real touch event, which greatly improves the accuracy of touch screen detection, avoids the occurrence of misjudgment, and ensures that the touch screen can accurately respond to real user touch behavior in various complex electromagnetic environments.

[0047] In one embodiment of the present invention, the control module is also used to determine the time domain signal and the total number of sampling points of the first digital signal if the first digital signal is a periodic signal, determine the frequency domain signal of the first digital signal based on the time domain signal and the total number of sampling points of the first digital signal, and determine the first frequency based on the frequency domain signal of the first digital signal.

[0048] In the embodiment of the present invention, the control module 105 can process the first digital signal and the second digital signal respectively according to the type of the first digital signal and the second digital signal. For example, if the touch signal and the noise signal are periodic signals, they can be converted from time domain signals to frequency domain signals through Fourier transform. Specifically, the corresponding frequency domain signal can be calculated by formula (1):

[0049]

[0050] Among them, X[k] represents the frequency domain signal, corresponding to the component of frequency k; x[n]: the original time domain signal, with a length of N; n: the time index, ranging from 0 to N-1, representing the sample point of the current signal; N: the total number of sampling points of the signal; k: the frequency index, representing the frequency component currently being calculated, ranging from 0 to N-1.

[0051] After calculating the frequency domain signal, the acquisition frequency in the frequency domain signal can be extracted, and then the first frequency can be calculated according to formula (2):

[0052]

[0053] Among them, f k Refers to the first frequency, f s Refers to the acquisition frequency.

[0054] Similarly, when calculating the second frequency of the second digital signal, formula (1) and formula (2) may also be used for calculation.

[0055] It should be noted that since the operating frequency of the touch screen is generally between tens of KHz and 1MHz, when performing frequency comparison, the frequency points below 5KHz and above 1MHz can be filtered out by digital filtering, and only the frequency points between 5KHz and 1MHz can be compared.

[0056] In one embodiment of the present invention, the control module is further used to determine the scale factor and preset mother wavelet constant corresponding to the first digital signal if the first digital signal is a non-periodic signal; and determine the first frequency according to the scale factor and the preset mother wavelet constant.

[0057] In the embodiment of the present invention, when the touch signal and the noise signal are non-periodic signals, the wavelet transform can be used to calculate the first frequency. The corresponding mother wavelet can be determined according to the touch signal, and then the scale factor corresponding to the mother wavelet is determined, and then the corresponding preset mother wavelet constant is obtained. Then, the corresponding first frequency is determined according to formula (3):

[0058]

[0059] Among them, fk refers to the first frequency, c refers to the wavelet constant, and a refers to the scale factor.

[0060] Similarly, when calculating the second frequency of the second digital signal, it can also be calculated using formula (3).

[0061] In one embodiment of the present invention, the control module is also used to determine the first envelope modulus value corresponding to the first digital signal and the second envelope modulus value corresponding to the second digital signal if the first frequency is consistent with the second frequency, and judge whether the first envelope modulus value is consistent with the second envelope modulus value; if the first envelope modulus value is consistent with the second envelope modulus value, filter out the touch signal.

[0062] In an embodiment of the present invention, when the first frequency and the second frequency are the same, it is necessary to perform signal envelope analysis on the two sets of data of the first digital signal and the second digital signal. If the signal envelopes are also the same, it is considered that the two key parameters of the first digital signal and the second digital signal are highly correlated.

[0063] Specifically, when the touch signal and the noise signal are periodic signals, the analytical signal z(t)=x(t)+jH[x(t)] can be obtained by performing Hilbert transform on x(t), where H[x(t)] is the Hilbert transform of x(t). Then, the envelope of the signal can be obtained by calculating the modulus of the analytical signal, that is, the envelope modulus value

[0064]

[0065] Similarly, A second envelope modulus value of the second digital signal is obtained by calculation.

[0066] If the first envelope modulus value is consistent with the second envelope modulus value, it is determined that the touch signal is an abnormal noise signal, and the touch signal sensed by the touch screen can be filtered out without reporting a point.

[0067] When the touch signal and the noise signal are non-periodic signals, the wavelet transform coefficients can be calculated by formula (4):

[0068]

[0069] Among them, a is the scale factor, which controls the expansion and contraction of the wavelet. b is the translation factor, which controls the position of the wavelet. W(a,b) refers to the wavelet transform coefficient, which contains the information of the signal at scale a and position b. f(t) refers to the frequency.

[0070] Further, the envelope modulus value is calculated by formula (5):

[0071]

[0072] Wherein, Re represents the real part of the wavelet transform coefficient, and Im represents the imaginary part of the wavelet transform coefficient.

[0073] In an embodiment of the present invention, the analog-to-digital conversion module is further used to process the touch signal to obtain a processed touch signal, and convert the processed touch signal into a first digital signal.

[0074] In the embodiment of the present invention, the touch signal acquired by the acquisition module is often a relatively primitive analog signal, which may contain some factors that are not conducive to subsequent accurate judgment and analysis. For example, the touch signal may be mixed with noise interference from the surrounding environment, or its signal strength, waveform, etc. do not meet the optimal requirements of the subsequent digital processing link. Therefore, it is necessary to process the touch signal to improve the signal quality and optimize the signal characteristics, so as to more accurately convert it into a digital signal and use it to judge the effectiveness of the touch operation.

[0075] The initial strength of the touch signal may not be appropriate. It may be too weak to be accurately detected, or too strong to exceed the effective input range of the analog-to-digital conversion module. At this time, the analog-to-digital conversion module can amplify or attenuate the touch signal. If the signal is weak, it is amplified to a suitable amplitude through the amplifier circuit so that the signal changes can be more clearly distinguished later. If the signal strength exceeds the range that the analog-to-digital conversion module can handle, the attenuation circuit is used to appropriately reduce the signal strength to ensure that it can be accurately converted into a digital signal. For example, when the voltage amplitude range of the touch signal is 0.1V-0.5V, but the optimal input range of the analog-to-digital conversion module is 1V-5V, the touch signal needs to be amplified to the corresponding appropriate range through a suitable amplifier circuit.

[0076] For example, the touch signal can be shaped to make its waveform more regular and closer to the ideal analog input signal form, so as to facilitate sampling and quantization by the analog-to-digital conversion module. For some irregular touch signal waveforms, they may be converted into regular waveforms such as square waves through circuits such as comparators to reduce conversion errors caused by complex waveforms. In addition, the signal can be linearized. If the relationship between the touch signal and the touch physical quantity is nonlinear, it can be converted into a linear relationship through the corresponding linearization circuit. In this way, the converted digital signal can more directly reflect the actual touch situation.

[0077] In one embodiment of the present invention, the analog-to-digital conversion module also includes an analog front-end module, which is used to perform baseline calibration on the touch signal, amplify the calibrated touch signal to obtain an amplified touch signal, and filter the amplified touch signal to obtain a processed touch signal.

[0078] In the embodiment of the present invention, Figure 2, shows a block diagram of another touch screen detection circuit provided by an embodiment of the present invention. The analog-to-digital conversion module 102 may also include an analog front-end module 1021. The analog front-end module 1021 may implement baseline calibration in a variety of ways. A common method is to detect the touch signal level when there is no touch operation for a period of time, record the average level as the baseline offset, and then, when the touch signal is subsequently received, subtract the baseline offset from the real-time touch signal, so that the baseline of the touch signal is calibrated to the desired reference level. For example, if the average signal level when no touch is detected is 0.2V, then the amplitude of each touch signal will be subtracted by 0.2V, so as to implement baseline calibration;

[0079] Further, the analog front-end module 1021 can use different types of filters to implement the filtering function. Common ones include low-pass filters, high-pass filters, and band-pass filters. If you mainly want to remove high-frequency electromagnetic interference noise, you can choose a low-pass filter, which allows the low-frequency components in the touch signal to pass through, while attenuating or blocking the high-frequency noise components; the high-pass filter is the opposite, and can be used to remove low-frequency interference such as DC bias or some slowly changing baseline drifts, etc., to highlight the rapidly changing signal part caused by the touch action; the band-pass filter can set a specific frequency range and only allow the touch signal components within the frequency band to pass, and further screen out the effective components that are more in line with the characteristics of the touch signal; for example, in the case where the frequency components in the touch signal are mainly concentrated in a few hundred Hz to a few thousand Hz, a band-pass filter with a suitable bandwidth can be selected to filter out the noise in other frequency bands and improve the purity of the signal.

[0080] In an embodiment of the present invention, the analog-to-digital conversion module further includes a second analog-to-digital converter, and the second analog-to-digital converter is used to convert the processed touch signal into a first digital signal.

[0081] In the embodiment of the present invention, the analog-to-digital conversion module further includes a second analog-to-digital converter 1022 , and the second analog-to-digital converter 1022 can convert the processed touch signal into a first digital signal.

[0082] In an embodiment of the present invention, the detection circuit further includes a power supply module, which is connected to the acquisition module and the operational amplifier module respectively, and is used to supply power to the acquisition module and the operational amplifier module.

[0083] In the embodiment of the present invention, Figure 2 The detection circuit may further include a power supply module 106, which is connected to the acquisition module 101 and the operational amplifier module 103 respectively. The power supply module may output direct current to power the acquisition module 101 and the operational amplifier module 103 respectively.

[0084] In one embodiment of the present invention, the power supply module includes an AC power supply, a DC conversion module, and a low-voltage difference linear regulator. The DC conversion module is connected to the AC power supply and the low-voltage difference linear regulator respectively; the DC conversion module is used to convert the AC power output by the AC power supply into DC power, and output the DC power to the low-voltage difference linear regulator; the low-voltage difference linear regulator is used to convert DC power into low-voltage DC power and input it into the acquisition module and the operational amplifier module.

[0085] In the embodiment of the present invention, Figure 2 The power supply module includes an AC power supply 1061, a DC conversion module 1062, and a low voltage dropout linear regulator 1063, and the DC conversion module 1062 is connected to the AC power supply 1061 and the low voltage dropout linear regulator 1063 respectively;

[0086] The AC power supply 1061 is usually the power input source of the entire power module. It provides the original power for subsequent conversion and voltage stabilization operations. In many practical application scenarios, such as industrial environments, places where large electronic equipment is located, or ordinary consumer electronic products connected to the mains, the AC power supply often comes from the power grid, which has the characteristics of relatively fixed voltage and frequency. For example, the common mains is 220V, 50Hz (in my country) or 110V, 60Hz (in some other countries or regions). This relatively stable and widely available AC power provides a convenient power supply basis for many electronic devices. However, due to its high voltage amplitude and AC form, it cannot be directly used in the acquisition module and operational amplifier module in the touch screen detection circuit that require stable low-voltage DC power, so subsequent conversion and voltage stabilization processing is required.

[0087] The DC conversion module 1062 is in the middle link of the power module. First, the AC power output by the AC power supply must be converted into DC power. This process is generally achieved through a rectifier circuit. Common rectification methods include half-wave rectification, full-wave rectification, and bridge rectification. For example, the bridge rectifier circuit uses a rectifier bridge composed of four diodes, which can convert the positive and negative half cycles of the input AC power into the same direction of DC power, and convert the AC signal into a pulsating DC signal to meet the input requirements of the subsequent low-voltage difference linear regulator and the basic requirements of the entire circuit for power quality.

[0088] Low Dropout Regulator 1063 (LDO) is a commonly used linear voltage regulator chip. Its main function is to convert the input DC power into low-voltage DC power and input it into the acquisition module and operational amplifier module. Its voltage regulation principle is based on the working characteristics of the linear adjustment tube. Through the feedback control mechanism, the conduction degree of the adjustment tube is continuously adjusted so that the output voltage can remain relatively stable when factors such as input voltage and load current change. For example, 22V voltage can be converted into a low voltage of 5V or 3.3V.

[0089] In one embodiment of the present invention, the control module includes a controller, and the controller is used to determine that the touch signal is valid if the first frequency is inconsistent with the second frequency, perform point reporting processing on the touch signal, and execute an action corresponding to the touch signal.

[0090] In an embodiment of the present invention, the control module 105 includes a controller 1051. After receiving the first frequency corresponding to the first digital signal and the second frequency corresponding to the second digital signal, the controller 1051 will compare and determine whether the two are consistent. When it is determined that the first frequency and the second frequency are inconsistent, it is determined that the touch signal is valid, which means that the touch signal change at this time is not a false situation caused by noise interference, but is indeed from a valid touch operation. Therefore, the controller determines that the touch signal is valid based on this.

[0091] The present invention can effectively distinguish between real touch and false triggering caused by noise interference, greatly improving the accuracy and reliability of touch screen detection. In environments such as industrial control where there is strong electromagnetic interference or when daily consumer electronic devices are used in complex electromagnetic environments, the touch screen is easily affected by various noises. Through such accurate judgment, unnecessary operations due to false judgment can be avoided, thereby improving user experience and ensuring the normal functioning of the touch screen.

[0092] Point reporting processing refers to the process in which the controller processes and reports the touch position information corresponding to the touch signal after determining that the touch signal is valid. There are many sensors distributed on the surface of the touch screen. When the finger touches different positions of the screen, these sensors will produce different touch signal changes. By analyzing and processing these signals, the controller can determine the specific coordinate position of the touch point on the screen. This process of determining the coordinates of the touch point is the core content of point reporting processing. For example, in common capacitive touch screens, different touch point positions will result in different capacitance changes at the corresponding positions. The controller uses relevant positioning algorithms and combines the touch signal characteristics to calculate the precise position coordinates of the touch point in the screen coordinate system, such as (x, y) coordinate values, and reports these coordinate information to other related modules or applications in the system in a certain format and communication protocol.

[0093] Take the touch screen of a mobile phone as an example: when a person presses the screen (the mobile phone screen is generally layered as follows: LCD screen: outermost glass + touch screen + liquid crystal + backlight layer, OLED screen: outermost glass + organic light-emitting layer (including touch layer) + large-scale switch tube control circuit), the touch screen senses that the capacitance value of the position where the person's finger is located has changed. If the change is greater than a certain range from the reference value, it is considered to be a valid touch. The touch screen control IC will report this point to the superior processor, such as the main control CPU of the mobile phone, and the CPU will respond to the action that should be taken when the position is pressed. For example, if the user presses the phone icon, the response of the mobile phone CPU is to jump out of the dialing interface and wait for the user to further dial operations.

[0094] After completing the reporting point processing, the controller will further execute the actions corresponding to the touch signal. These actions depend on the specific equipment and software environment used by the touch screen, and cover a wide range. On a smart phone, the corresponding action of touch may be to open an application, slide the screen to switch pages, zoom in and out on a picture, etc.; on a tablet computer, it may involve clicking on a document to edit it, dragging a file to move it, etc.; and in an industrial control touch screen, it may be to start or stop a device, adjust the operating parameters of the device, etc. In short, the controller will trigger the corresponding operation based on the meaning represented by the touch signal and the functional logic preset by the device and software to realize the human-computer interaction function.

[0095] The controller does not perform these actions independently, but needs to work closely with the operating system, application, etc. of the entire device. It will pass the operation instructions corresponding to the touch signal to the operating system through the corresponding communication interface. The operating system will then call the corresponding functional module to perform specific actions based on the specific application scenario and the currently running application. For example, when you touch the screen on a smartphone to open the camera application, the controller first determines that the touch signal is valid and determines that the touch position corresponds to the camera icon, and then sends the instruction to open the camera application to the mobile phone operating system. After receiving the instruction, the operating system starts the camera application and completes the corresponding action response. The whole process involves collaboration and cooperation between software and hardware modules at multiple levels.

[0096] Through this series of functions, the controller in the control module realizes the effective connection between the touch screen detection circuit and the human-computer interaction function, from judging the validity of the touch signal to performing point reporting processing and then executing corresponding actions, ensuring that the touch screen can accurately and sensitively respond to the user's touch operations in various application scenarios.

[0097] In one embodiment of the present invention, Figure 2The detection circuit may further include a driver 107. The controller 1051 may be configured to control the driver 107 to filter out the collected touch signal by sending an instruction to the driver 107 when the touch signal is determined to be an abnormal noise signal.

[0098] like Figure 3 , showing a schematic diagram of a process for detecting a touch signal provided by an embodiment of the present invention, collecting a touch signal, converting the touch signal into a first digital signal, converting a noise signal collected from a power supply into a second digital signal, and then performing frequency analysis on the first digital signal and the second digital signal to determine whether the frequencies are consistent. If the frequencies are inconsistent, it is determined to be a valid touch signal and a point report can be made; if the frequencies are consistent, an envelope analysis is required at this time. If they are consistent, the touch signal needs to be filtered out and no point report is made. If the envelopes are inconsistent, the touch signal is a valid touch signal and a point report is required.

[0099] The present invention discloses a detection circuit for a touch screen, which can obtain a first digital signal by processing a touch signal, then amplify a noise signal to obtain an amplified noise signal, convert the amplified noise signal into a second digital signal, and determine whether the touch signal is valid by combining the first digital signal and the second digital signal through a control module. The circuit can effectively distinguish between a real touch operation and a false touch signal caused by noise, and can enable a terminal device with a touch screen to be used normally even in a poor power supply environment, avoiding interference from power supply noise, and preventing false alarm points. The circuit has high reliability, thereby improving user experience.

[0100] like Figure 4 , shows a structural block diagram of a terminal device 20 provided in an embodiment of the present invention, wherein the terminal device 20 includes a detection circuit 201 and a touch screen 202 as described above for the touch screen.

[0101] As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0102] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0103] It will be appreciated by those skilled in the art that the embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0104] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0105] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0106] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable terminal device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0107] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0108] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0109] The above is a detailed introduction to a touch screen detection circuit and a terminal device provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A detection circuit for a touch screen, characterized in that: The detection circuit of the touch screen comprises: An acquisition module, used for acquiring a touch signal of the touch screen; an analog-to-digital conversion module, connected to the acquisition module, and configured to determine a first digital signal according to the touch signal; An operational amplifier module, used to obtain a noise signal, amplify the noise signal, and obtain an amplified noise signal; A first analog-to-digital converter, connected to the operational amplifier, and configured to convert the amplified noise signal into a second digital signal; The control module is connected to the analog-to-digital conversion module and the first analog-to-digital converter, respectively, and is used to obtain the first digital signal and the second digital signal, and determine whether the touch signal is valid according to the first digital signal and the second digital signal.

2. The detection circuit of the touch screen according to claim 1, characterized in that: The control module is used to determine a first frequency corresponding to the first digital signal and a second frequency corresponding to the second digital signal, and judge whether the first frequency is consistent with the second frequency. If the first frequency is inconsistent with the second frequency, it is determined that the touch signal is valid.

3. The detection circuit of the touch screen according to claim 2, characterized in that: The control module is also used to determine the time domain signal and the total number of sampling points of the first digital signal if the first digital signal is a periodic signal, determine the frequency domain signal of the first digital signal according to the time domain signal and the total number of sampling points of the first digital signal, and determine the first frequency according to the frequency domain signal of the first digital signal.

4. The detection circuit of the touch screen according to claim 2, characterized in that: The control module is further configured to determine a scale factor and a preset mother wavelet constant corresponding to the first digital signal if the first digital signal is a non-periodic signal; and determine the first frequency according to the scale factor and the preset mother wavelet constant.

5. The detection circuit of the touch screen according to claim 2, characterized in that: The control module is also used to determine a first envelope modulus value corresponding to the first digital signal and a second envelope modulus value corresponding to the second digital signal if the first frequency is consistent with the second frequency, and judge whether the first envelope modulus value is consistent with the second envelope modulus value; if the first envelope modulus value is consistent with the second envelope modulus value, filter out the touch signal.

6. The detection circuit of the touch screen according to claim 1, characterized in that: The analog-to-digital conversion module is further used to process the touch signal to obtain a processed touch signal, and convert the processed touch signal into the first digital signal.

7. The detection circuit of the touch screen according to claim 6, characterized in that: The analog-to-digital conversion module also includes an analog front-end module, which is used to perform baseline calibration on the touch signal, amplify the calibrated touch signal to obtain an amplified touch signal, and filter the amplified touch signal to obtain the processed touch signal.

8. The detection circuit of the touch screen according to claim 7, characterized in that: The analog-to-digital conversion module further includes a second analog-to-digital converter, and the second analog-to-digital converter is used to convert the processed touch signal into the first digital signal.

9. The detection circuit of the touch screen according to claim 1, characterized in that: The detection circuit also includes a power supply module, which is connected to the acquisition module and the operational amplifier module respectively, and is used to supply power to the acquisition module and the operational amplifier module.

10. The detection circuit of the touch screen according to claim 9, characterized in that: The power supply module includes an AC power supply, a DC conversion module, and a low voltage drop linear regulator, and the DC conversion module is connected to the AC power supply and the low voltage drop linear regulator respectively; The DC conversion module is used to convert the AC power output by the AC power supply into DC power, and output the DC power to the low voltage drop linear regulator; The low voltage drop linear regulator is used to convert the direct current into low voltage direct current and input it into the acquisition module and the operational amplifier module.

11. The detection circuit of the touch screen according to claim 2, characterized in that: The control module includes a controller, and the controller is used to determine that the touch signal is valid if the first frequency is inconsistent with the second frequency, perform point reporting processing on the touch signal, and execute an action corresponding to the touch signal.

12. A terminal device, characterized in that: The terminal device comprises the touch screen detection circuit and the touch screen as described in any one of claims 1 to 11.

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