CN116578203A - Capacitive touch driving method, transmitting device, receiving device and touch screen - Google Patents
Capacitive touch driving method, transmitting device, receiving device and touch screen Download PDFInfo
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- 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
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- 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
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- 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
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Abstract
The invention relates to a capacitive touch driving method, a transmitting device, a receiving device and a touch screen, wherein during scanning, any scanning line TXn is driven by a first frequency in a first time area and a second frequency in a second time area, and the first frequency and the second frequency are different. The invention can measure signals with a plurality of frequencies at the same time, thereby better inhibiting the influence of environmental noise and improving the anti-interference capability of the touch screen; the amplitude and the phase of signals with different frequencies can be adjusted according to the position of the touch point, the pressure change and other factors, so that the sensitivity of the touch screen is improved; in addition, the invention not only can measure and analyze signals with a plurality of frequencies and reduce the influence of factors such as temperature drift, capacitance drift and the like on a measurement result, thereby realizing more accurate touch positioning; and only the needed frequency can be selected for detection according to the actual situation, so that unnecessary power consumption is avoided.
Description
Technical Field
The invention relates to the technical field of touch control, in particular to a capacitive touch driving method, a sending device, a receiving device and a touch screen.
Background
Capacitive touch screens are a common touch screen technology that enables detection and response to touches based on capacitive principles. The driving method generally comprises the following steps:
transmitting a scanning signal: the touch screen is covered with a conductive film, and when a user touches the screen, the capacitance of the conductive film changes, and the change can be detected. To detect this variation, the drive circuit needs to send a series of scan signals, typically generated by an alternating electric field, over the conductive film, which signals are received and processed by the touch screen controller;
receiving the signal and calculating the capacitance value: the controller receives a feedback signal when the touch screen is scanned. These signals are used to calculate capacitance values to determine the location and magnitude of the touch;
decoding position and command: once the touch location is detected, the controller converts it into coordinates and communicates it to the processor of the device. The processor decodes the coordinates and determines the operation the user wants to perform;
the operation is performed: the device may perform corresponding operations such as scrolling through a screen, zooming in and out, selecting menu items, etc.
The driving method of the capacitive touch screen mainly comprises the following steps:
electrostatic induction type driving method (capacitive driving): the electrostatic induction type driving method detects a touch point on a touch screen by inducing a change in an electric field. When a finger approaches the capacitive screen, a change in capacitance occurs, by which the location of the touch point can be detected. The method has the advantages of high sensitivity and quick response.
Resistive driving method: the resistive driving method is a method of detecting the position of a touch point using two conductive films. When a finger touches the screen, the resistance value between the two conductive films changes, and the position of the touch point can be detected through the change. The method has higher precision and stability than the static induction driving method.
Capacitive reactance driving method: the capacitive reactance type driving method is a method of detecting the position of a touch point using a set of conductive coils and conductive films which are staggered. When a finger touches the screen, the capacitance between the conductive coil and the conductive film is changed, and the position of the touch point can be detected by this change. The method has higher sensitivity and faster response speed than the resistive driving method.
The acoustic wave driving method comprises the following steps: the acoustic wave driving method is a method of detecting the position of a touch point using an ultrasonic transmitter and receiver. When a finger touches the screen, some tiny sound waves are generated, and the position of the touch point can be detected by reflection and interference between the ultrasonic transmitter and receiver. The method has the advantages of high precision and no physical contact.
The above is a few common capacitive touch screen driving methods, and different driving methods have different advantages and application scenarios.
In the electrostatic induction type touch screen, a layer of conductive substance is arranged on the screen as a capacitive plate, and is generally transparent conductive glass or an ITO film; conductive induction coils are mounted around and at the corners of the conductive plate and are electrically connected to the controller.
When a finger or other conductive object approaches the conductive plate, a change in the electric field occurs. This change is captured by the sense coil and the controller calculates the location of the touch point by an algorithm.
The advantages of the static induction type touch screen include:
the sensitivity is high: the electrostatic induction type touch screen is very sensitive to the change of a touch point, and can accurately detect the position of a finger or other conductive objects.
The reaction speed is high: since the electrostatic induction type touch screen only needs to detect the change of the electric field, the response speed is very fast.
The precision is high: the electrostatic induction type touch screen has the characteristic of high precision, and can detect very small position change of a touch point.
The durability is strong: since the electrostatic induction type touch screen has no physical contact portion, it has high durability.
However, electrostatic induction type touch screens also have some drawbacks. For example, the non-conductive object cannot be sensed, and meanwhile, the layout and the number of the sensing lines and other factors need to be considered in design, so that certain cost and design difficulty are increased. In addition, since the electrostatic induction type touch screen depends on a change in an electric field, false touch may be generated in an environment of strong electromagnetic interference.
Self-capacitance touch screens and mutual capacitance touch screens are two common capacitive touch screen driving methods.
The circuit structure of the self-contained touch screen is simple, a certain number of sensing electrodes are only required to be arranged on the periphery or the edge of the touch screen, and then the position of a touch point is calculated by using an algorithm in a controller. In a self-capacitance type touch screen, the capacitance between the sensing electrode and the touch point becomes self-capacitance. When a finger or other object touches the touch screen, a change in the charge distribution will occur, resulting in a change in the self-capacitance on the touch screen, which the controller can measure to determine the location of the touch point. The self-contained touch screen has the advantages of high response speed, simple structure and the like, but has low sensitivity and cannot detect a plurality of touch points at the same time. When the electrodes are arranged in the X direction and the Y direction, the position of the touch point of the touch screen can be detected.
The mutual capacitance type touch screen is characterized in that two capacitance plates are placed on the touch screen, one is a transverse capacitance plate, the other is a longitudinal capacitance plate, and the two capacitance plates are crossed to form a capacitance matrix. Each crossing point on the capacitive plate can act as a sensing electrode, so that the location of the touch point can be detected. In a mutual capacitance type touch screen, the capacitance between the capacitance plates becomes mutual capacitance. When a finger or other object touches the touch screen, a change in the charge distribution occurs, resulting in a change in the mutual capacitance in the capacitive matrix, which the controller can measure to determine the location of the touch point. The mutual capacitance type touch screen has the advantages of high sensitivity, high precision and the like, but has a complex structure, needs more sensing electrodes and controller resources, and has relatively high cost.
In short, the self-capacitance type touch screen and the mutual capacitance type touch screen have advantages and disadvantages and are suitable for different application scenes. The choice of which type of touch screen requires trade-offs depending on the specific application requirements and cost budget.
In recent years, capacitive touch is getting more and more favor of users due to the advantages of high sensitivity and high touch precision, and sine wave driving and square wave driving are two driving technologies of capacitive touch screen driving.
The sine wave drive detects touch events by applying a sine wave signal on the capacitive screen. This driving scheme utilizes the frequency and amplitude of the sine wave signal to determine the location of the touch point. Under the action of the sine wave signal, the position of the touch point can generate tiny disturbance on the signal, and the disturbance can be reflected in the capacitance change of the capacitive screen. The controller may determine the location of the touch point by measuring the magnitude and phase difference of the capacitance changes. The sine wave driving mode has the advantages of high precision, high sensitivity, low power consumption and the like, but requires more complicated circuits and algorithms.
The square wave drive detects a touch event by applying a square wave signal on the capacitive screen. A square wave signal is a signal with a high frequency and a fast rise time. When a finger touches the screen, the capacitance value of the capacitive screen is changed, resulting in a change in the amplitude of the square wave signal. The controller may determine the location of the touch point by measuring the amplitude and phase difference of the square wave signals. The square wave driving mode has the advantages of high response speed, low cost and the like, but is easy to generate false touch in a noisy environment.
To overcome the above problems, a series of interference suppression measures such as shielding, filtering, adding a power filter, adding a ground resistance, etc. are generally adopted in the prior art to improve the stability and the anti-interference capability of the touch screen. The effective method is a frequency hopping driving method, firstly, a capacitive touch screen is scanned at different frequencies according to a set series of frequency hopping sequences, and meanwhile, the signal response condition of each frequency is recorded; finally, through analyzing and processing the signal responses, the minimum noise interference of the touch screen under a certain frequency is determined, and then the driving frequency with the minimum interference is selected to start formal scanning. Therefore, this requires a pre-scan of different frequencies and analysis and processing of the signal response before the touch screen is scanned formally. The reflection speed is reduced due to wasted time and power consumption. In addition, since the formal scan is different from the time point of the preliminary scan, the state of the interference signal may be different between these two periods.
Disclosure of Invention
Therefore, the invention aims to solve the technical problems of complex circuit and anti-interference performance in the prior art, and provides a capacitive touch driving method with simple circuit and better anti-interference performance, a transmitting device, a receiving device and a touch screen.
In order to solve the above technical problems, in the capacitive touch driving method of the present invention, during formal scanning, any one of scan lines TXn is driven at a first frequency in a first time region and at a second frequency in a second time region, where the first frequency and the second frequency are different.
In one embodiment of the present invention, in the regular scanning, a first frequency driving is used for any one of the scanning lines TXn in a first time region, a second frequency driving is used in a second time region, the first frequency and the second frequency are different, a first voltage V1 is applied to a first scanning line TX1, a second voltage V2 is applied to a second scanning line TX2, a third voltage V3 is applied to a third scanning line TX3, a fourth voltage V4 is applied to a fourth scanning line TX4, and v4+.v1+v2+v3, v4+.v1+v3, v3+.v1+v2 are applied.
In one embodiment of the present invention, during the formal scan, a first frequency driving is used for any one scan line TXn in a first time region, a second frequency driving is used in a second time region, the first frequency and the second frequency are different, a first voltage V1 is applied to a first scan line TX1, a second voltage V2 is applied to a second scan line TX2, a third voltage V3 is applied to a third scan line TX3, a fourth voltage V4 is applied to a fourth scan line TX4, four different voltages are applied to four scan lines respectively as periods, and the first voltage V1 to the fourth voltage V4 are sequentially applied to four scan lines of a next consecutive period in turn until the scan of all scan lines is completed.
In one embodiment of the present invention, during regular scanning, any one scan line TXn is driven at a first frequency in a first time region, and at a second frequency in a second time region, where the first frequency and the second frequency are different, and the capacitance difference Rdx (n-1) between any two adjacent detection lines RXn-1, RXn satisfies Rdx (n-1) = (RXn-1-RXn).
The invention also provides a transmitting device, which comprises: a signal generator for generating signals of a plurality of frequencies; a Hadamard encoder for encoding the signal; the signal generator and the Hadamard encoder are connected with the first mixer and are used for mixing signals with a plurality of frequencies and coded signals; the digital-to-analog conversion circuit is connected with the first mixer and is used for converting the mixed signals into analog signals; the first low-pass filter is connected with the digital-to-analog conversion circuit and is used for filtering signals; and the multiplexer is connected with the first low-pass filter.
In one embodiment of the invention, the multiplexer is coupled to a plurality of drivers.
In one embodiment of the invention, the actuator is connected to a pressurizer.
The invention also provides a receiving device, which comprises: a digital controller; at least one path of transmission device comprises: an analog front-end circuit connected to the digital controller; an analog converter connected to the digital controller and the analog front-end circuit, respectively; the digital controller is connected with the second mixer through a mixing wave regulator, and the analog converter is connected with the second mixer; and the baseband demodulator is respectively connected with the second mixer and the digital controller.
In one embodiment of the invention, the digital controller is connected to the mixing regulator by a delay.
In one embodiment of the invention, the analog front-end circuit includes a fully differential charge amplifier, a programmable gain amplifier, and a second low pass filter, and the fully differential charge amplifier is coupled to the second low pass filter through the programmable gain amplifier, the second low pass filter being coupled to the analog converter.
The invention also provides a touch screen, which comprises the transmitting device and the receiving device.
Compared with the prior art, the technical scheme of the invention has the following advantages:
according to the capacitive touch driving method, the sending device, the receiving device and the touch screen, signals with multiple frequencies can be measured at the same time, so that the influence of environmental noise can be well restrained, and the anti-interference capability of the touch screen is improved; the amplitude and the phase of signals with different frequencies can be adjusted according to the position of the touch point, the pressure change and other factors, so that the sensitivity of the touch screen is improved; in addition, the invention not only can measure and analyze signals with a plurality of frequencies and reduce the influence of factors such as temperature drift, capacitance drift and the like on a measurement result, thereby realizing more accurate touch positioning; and only the needed frequency can be selected for detection according to the actual situation, so that unnecessary power consumption is avoided.
Drawings
In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings, in which
FIG. 1 is a flow chart of a capacitive touch driving method according to an embodiment of the invention;
FIG. 2 is a flow chart of a capacitive touch driving method according to a second embodiment of the invention;
FIG. 3 is a flow chart of a capacitive touch driving method according to a third embodiment of the invention;
fig. 4 is a schematic diagram of a transmitting device according to a fourth embodiment of the present invention;
fig. 5 is a schematic diagram of a receiving device according to a fifth embodiment of the present invention;
FIG. 6 is a schematic diagram of an analog front-end circuit of the present invention.
Description of the drawings: 10. a signal generator; 11. a Hadamard encoder; 12. a filter; 13. a first mixer; 14. a digital-to-analog conversion circuit; 15. a first low pass filter; 16. a multiplexer; 17. a driver; 18. a pressurizer; 20. a digital controller; 21. analog front-end circuitry; 211. a fully differential charge amplifier; 212. a programmable gain amplifier; 213. a second low pass filter; 22. an analog converter; 23. a second mixer; 24. a mixing regulator; 25. a baseband demodulator; 26. a delay device.
Detailed Description
Example 1
As shown in fig. 1, this embodiment provides a capacitive touch driving method, in which, during formal scanning, any one scan line TXn is driven at a first frequency in a first time region and at a second frequency in a second time region, and the first frequency and the second frequency are different.
In the capacitive touch driving method of this embodiment, during the formal scan, since any one of the scan lines TXn is driven at a first frequency in a first time region and driven at a second frequency in a second time region, and the first frequency and the second frequency are different, if the first frequency is interfered by noise of the same frequency, the signal analysis and processing can be performed on the received signal driven at the 2 nd frequency. The invention can measure signals with a plurality of frequencies at the same time, thereby better inhibiting the influence of environmental noise and improving the anti-interference capability of the touch screen; the amplitude and the phase of signals with different frequencies can be adjusted according to the position of the touch point, the pressure change and other factors, so that the sensitivity of the touch screen is improved; in addition, the invention not only can measure and analyze signals with a plurality of frequencies and reduce the influence of factors such as temperature drift, capacitance drift and the like on a measurement result, thereby realizing more accurate touch positioning; and only the needed frequency can be selected for detection according to the actual situation, so that unnecessary power consumption is avoided.
In order to further avoid noise interference, a third frequency is used to drive any one of the scan lines TXn in a third time region, and the third frequency is different from the first frequency and the second frequency, so that if the first frequency and the second frequency are interfered by noise of the same frequency, signal analysis and processing can be performed on the received signal driven by the third frequency.
As shown in fig. 1, for the scan lines TX1, TX2, TX3, TX4, the first frequency f1 is used for driving in the first time T1 region, and the second frequency f2 is used for driving in the second time T2 region, so if the first frequency f1 is interfered by the noise of the same frequency, the signal analysis and processing can be performed on the received signal driven by the 2 nd frequency f 2.
Example two
As shown in fig. 2, this embodiment provides a capacitive touch driving method, which uses the scanning method described in the first embodiment, and applies the first voltage V1 to the first scanning line TX1, the second voltage V2 to the second scanning line TX2, the third voltage V3 to the third scanning line TX3, the fourth voltage V4 to the fourth scanning line TX4, and sequentially applies the nth voltage Vn to the nth scanning line TXn, where Vn is not equal to Vn-3+vn-2+vn-1, vn is not equal to Vn-3+vn-1, and Vn is not equal to Vn-2+vn-1.
In the capacitive touch driving method according to the present embodiment, the scanning method according to the first embodiment is used, and a high-voltage driving method is used during formal scanning, specifically, the first voltage V1 is applied to the first scanning line TX1, the second voltage V2 is applied to the second scanning line TX2, the third voltage V3 is applied to the third scanning line TX3, and the fourth voltage V4 is applied to the fourth scanning line TX4, where v4+.v1+v2+v3, v4+.v1+v3, v3+.v1+v2 are given by using characteristics of different voltages, so that noise interference to driving signals can be reduced, and an unclear voltage source at a receiving end is avoided.
In practical operation, in order to avoid complex circuits and save cost, only one touch voltage is usually used, but signals are easy to be interfered. In this embodiment, various driving voltages, such as four driving voltages, are provided, so that the first voltage V1 to the fourth voltage V4 are applied to the first scan line TX1 to the fourth scan line TX4, respectively, and in consideration of cost, the first voltage V1 to the fourth voltage V4 are continuously and repeatedly applied to the fifth scan line TX5 to the eighth scan line TX8 during actual operation, and the cycle is repeated until the scanning of the nth scan line TXn is completed.
Specifically, during formal scanning, a first frequency driving is used for any one scanning line TXn in a first time region, a second frequency driving is used in a second time region, the first frequency and the second frequency are different, a first voltage V1 is applied to a first scanning line TX1, a second voltage V2 is applied to a second scanning line TX2, a third voltage V3 is applied to a third scanning line TX3, a fourth voltage V4 is applied to a fourth scanning line TX4, four different voltages are applied to the four scanning lines respectively as periods, the first voltage V1 to the fourth voltage V4 are continuously applied to the four scanning lines of the next continuous period in sequence until scanning of all the scanning lines is completed.
The high voltage driving is a driving method commonly used for a touch screen, and the principle is to apply a high voltage signal to the touch screen, and transfer charges to a human body or other proximity objects through a capacitive sensor, thereby detecting a touch operation.
Compared to the low-voltage driving method, the high-voltage driving has the following advantages:
the anti-interference capability is strong: the amplitude of the high-voltage driving signal is larger, the influence of external interference signals can be effectively resisted, and the stability and reliability of the touch screen are improved.
The response speed is high: the frequency of the high-voltage driving signal is high, so that the touch screen can respond to touch operation more quickly, and the user experience is improved.
The application range is wide: high voltage driving is applicable to various touch screen types including resistive, capacitive, and electrostatic induction touch screens.
The present invention applies high voltage driving to multi-frequency touch driving, and thus has the above-described advantages.
Example III
As shown in fig. 3, the present embodiment provides a capacitive touch driving method, which uses the scanning method described in the first embodiment, and the capacitance difference Rdx (n-1) between any two adjacent detection lines RXn-1, RXn satisfies Rdx (n-1) = (RXn-1-RXn) during the formal scanning.
In the capacitive touch driving method according to the present embodiment, the scanning method according to the first embodiment is utilized, and a differential driving method is adopted during the formal scanning, specifically, during the scanning, the capacitance difference Rdx (n-1) between any two adjacent detection lines RXn-1 and RXn satisfies Rdx (n-1) = (RXn-1-RXn), and the capability of noise interference resistance can be increased due to the design of differential reception at the receiving end Rx of the touch screen.
The differential driving method is one of the common driving methods for capacitive touch screens. Compared with a single-end driving method, the differential driving method can improve the anti-interference capability and the signal stability of the touch screen. The differential driving method drives the touch screen by simultaneously applying opposite signals to two electrodes of the touch screen. For example, in the X-axis direction, the controller will apply a forward signal on the left electrode and a reverse signal on the right electrode. In this way, when the finger of the user approaches the touch screen, the capacitance values of the left and right electrodes change, but since the applied signals are opposite, the capacitance change magnitudes of the two electrodes are equal but the directions are opposite, so that the influence of the interference signal on the touch signal can be reduced. The differential driving method can further enhance the anti-jamming capability. For example, in the X-axis direction, if the controller applies two sine wave signals to the left and right electrodes at the same time, and the phase difference of the two signals is 90 °, the phase difference demodulation technique can be implemented, thereby eliminating noise interference signals and improving the signal stability and anti-interference capability of the touch screen.
The present invention applies differential driving to multi-frequency touch driving and thus has the above-described advantages.
Example IV
As shown in fig. 4, the present embodiment provides a transmitting apparatus for generating the multi-frequency signal according to the first embodiment, including:
a signal generator 10 for generating signals of a plurality of frequencies;
a Hadamard encoder 11 for encoding a signal;
a first mixer 13, wherein the signal generator 10 and the Hadamard encoder 11 are connected to the first mixer 13, for mixing signals of a plurality of frequencies with the encoded signals;
a digital-to-analog conversion circuit 14 connected to the first mixer 13 for converting the mixed signal into an analog signal;
a first low-pass filter 15 connected to the digital-to-analog conversion circuit 14 for filtering the signal;
a multiplexer 16 connected to said first low-pass filter 15.
The transmitting device of this embodiment includes: the device comprises a signal generator 10, a Hadamard encoder 11, a first mixer 13, a digital-to-analog conversion circuit 14, a first low-pass filter 15 and a multiplexer 16, wherein the signal generator 10 is used for generating signals with a plurality of frequencies, the signals are mixed with the Hadamard encoder 11 and then input to the digital-to-analog conversion circuit 14, the signals are subjected to analog conversion, impurities are filtered through the first low-pass filter 15, and then the signals are input to the multiplexer 16, so that signals with different frequencies can be output.
In this embodiment, the Hadamard encoder 11 is connected to the first mixer 13 through a filter 12, and the filter 12 can filter out interference signals; in addition, the present embodiment is not limited to the use of the signal generator 10 to generate the multi-frequency signal, but a DSP chip, an FPGA chip, or a microcontroller may be used.
Wherein, the DSP chip uses a Digital Signal Processor (DSP) chip, which can conveniently generate a multi-frequency sine wave signal and adjust parameters such as frequency, amplitude, phase and the like through programming. And outputting the generated sine wave signals through a digital-to-analog conversion circuit and sending the sine wave signals to a touch screen controller so as to realize multi-frequency sine wave driving.
The FPGA chip is a Field Programmable Gate Array (FPGA) chip, can realize high-speed data processing and logic control functions, generates a plurality of sine wave signals through programming, and outputs the sine wave signals to the touch screen controller through a digital-to-analog conversion circuit.
The use of a microcontroller may be programmed to generate a plurality of sine wave signals and output to the touch screen controller via PWM. An external DAC chip may also be used to improve the accuracy and stability of the output signal.
The invention adopts the signal generator 10, the signal generator 10 can generate a plurality of sine wave signals, and the sine wave signals are processed by the amplifying circuit and the filter circuit and then output to the touch screen controller; and may be implemented using a specialized signal generator or self-designed circuit.
The Hadamard coding is a coding technique used in digital communication, which can combine a plurality of binary data streams into one coded data stream, thereby improving transmission efficiency and reliability. Hadamard coding is usually realized by using a matrix calculation method, and has the advantages of simplicity, reversibility, low error rate and the like. Hadamard decoding is a process of decoding Hadamard encoded data that can recover the original multiple binary data streams. Hadamard decoding is typically implemented using a matrix calculation method, requiring calculation using the same Hadamard matrix as that used in encoding, to recover the original binary data stream. The Hadamard encoding process can be described simply as: multiplying the binary data stream to be encoded by a Hadamard matrix to obtain the encoded data stream. For example, if 4 binary data streams are to be encoded into one encoded data stream, the encoding may be performed using a 4-order Hadamard matrix, resulting in a 4-bit encoded data stream. The Hadamard decoding process can be described simply as: multiplying the coded data stream by the inverse of the Hadamard matrix to obtain the original binary data stream.
The Hadamard encoder 11 is an encoding technique for communication and data transmission. The principle is that a series of matrix operations are carried out on the original data to obtain a group of coded data sequences, and the sequences can be restored into the original data through inverse matrix operations. Specifically, the Hadamard encoder 11 is a binary code, and the encoding mode is based on the characteristics of the Hadamard matrix. The Hadamard matrix is an orthogonal matrix having many excellent properties such that the inner product of any two rows or columns is 0 or 1, and its inverse is equal to the inverse of its transpose matrix. By using these properties, the original data sequence can be multiplied by the Hadamard matrix to obtain a set of encoded sequences. The decoding process of Hadamard coding is opposite to the coding process, namely, the coded sequence is multiplied by the inverse matrix of the Hadamard matrix to obtain an original data sequence. Hadamard coding has many advantages such as good orthogonality between symbols, strong noise immunity, low decoding complexity, etc. Therefore, it is widely used in the fields of digital communication, radio, radar, etc., to improve reliability and stability of data transmission.
The multiplexer 16 is connected to a plurality of drivers 17 to facilitate high voltage driving. Specifically, the driver 17 is connected with the pressurizer 18, and the amplitude of the high-voltage driving signal is larger, so that the influence of external interference signals can be effectively resisted, and the stability and reliability of the touch screen are improved; in addition, the frequency of the high-voltage driving signal is higher, so that the touch screen can respond to touch operation more quickly, and the user experience is improved.
Example five
As shown in fig. 5, the present embodiment provides a receiving apparatus including:
a digital controller 20;
at least one path of transmission device comprises:
an analog front-end circuit 21 connected to the digital controller 20;
an analog converter 22 connected to the digital controller 20 and the analog front-end circuit 21, respectively;
a second mixer 23, the digital controller 20 is connected to the second mixer 23 through a mixing regulator 24, and the analog converter 22 is connected to the second mixer 23;
and a baseband demodulator 25 connected to the second mixer 23 and the digital controller 20, respectively.
The receiving device of this embodiment includes: a digital controller 20; at least one transmission device, the digital controller 20 is connected with the transmission device, and the transmission device comprises: an analog front-end circuit 21 connected to the digital controller 20, the output of the analog front-end circuit 21 being controlled by the digital controller 20; an analog converter 22 connected to the digital controller 20 and the analog front-end circuit 21, respectively, wherein the analog converter 22 receives the signal output from the analog front-end circuit 21 and outputs the signal after analog conversion processing; the second mixer 23, the digital controller 20 is connected to the second mixer 23 through a mixing regulator 24, the analog converter 22 is connected to the second mixer 23, and the signal output by the analog converter 22 is mixed with the signal output by the mixing regulator 24 and then output; and a baseband demodulator 25 connected to the second mixer 23 and the digital controller 20, respectively, wherein the signal output from the second mixer 23 is input to the baseband demodulator 25, and processed and output.
In this embodiment, the hybrid regulator 24 is a demodulator commonly used in communication systems, and is capable of converting a received high-frequency signal into a baseband signal, so that signal processing is more convenient. Hybrid demodulators typically employ I/Q LO techniques, i.e., using the product of quadrature signals (real and imaginary parts) to effect frequency conversion of the signals. The principle of the I/Q LO technique is to split the frequency of the Local Oscillator (LO) into two orthogonal signals, i.e., sine and cosine signals (I/Q signals), which are then mixed with the received signal, respectively. After the mixing process, the original high frequency signal is converted into two low frequency signals, i.e., quadrature I/Q baseband signals. The I/Q LO technique has the advantage that it can effectively suppress mixer nonlinearity and local oscillator rejection problems, thereby improving the performance and stability of the demodulator. Meanwhile, since the I/Q signals are orthogonal, they can simultaneously perform digital signal processing, such as digital filtering, phase correction, etc., so that the functions of the demodulator are more flexible.
The baseband demodulator 25 is a digital signal processing technique for extracting digital information from analog signals. In digital baseband demodulation, an analog signal is first sampled, quantized, and encoded, and then transmitted to a digital baseband demodulator for demodulation. Digital baseband demodulation is a commonly used digital signal processing technique for converting a received modulated signal into a digital signal for processing. The direct digital demodulation method is a demodulation method based on a digital signal processing technology. In the method, the received analog signal is firstly subjected to analog-to-digital conversion and then filtered by a digital filter to obtain a baseband signal; next, a digital phase shifter is used to perform phase adjustment, and finally a digital demodulator is used to convert the baseband signal into a digital signal.
The analog front-end circuit 21 is provided with a receiving terminal for receiving a signal, and the signal is inputted into the analog front-end circuit 21 through the receiving terminal.
The digital controller 20 is connected to the mixer regulator 24 through a delay 26, and the delay 26 delays the signal for several seconds and outputs the signal to the baseband demodulator 25.
In order to realize the scanning by adopting the differential driving mode, as shown in fig. 6, the analog front-end circuit 21 includes a fully differential charge amplifier 211, a programmable gain amplifier 212, and a second low-pass filter 213, and the fully differential charge amplifier 211 is connected to the second low-pass filter 213 through the programmable gain amplifier 212, and the second low-pass filter 213 is connected to the analog converter 22.
The fully differential charge amplifier 211 is used only for differential operation, and is used only as a charge amplifier if it has only one receiving terminal.
Example six
The embodiment provides a touch screen, which comprises the transmitting device described in the fourth embodiment and the receiving device described in the fifth embodiment.
The touch screen according to the present invention includes the transmitting device according to the fourth embodiment and the receiving device according to the fifth embodiment, and therefore, the fourth and fifth embodiments have advantages, and the present embodiment also has all the advantages.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.
Claims (11)
1. A capacitive touch driving method, characterized in that: in the regular scanning, a first frequency driving is used for any one scanning line TXn in a first time region, and a second frequency driving is used in a second time region, wherein the first frequency and the second frequency are different.
2. A capacitive touch driving method, characterized in that: in the normal scanning, the first frequency driving is used for any one of the scanning lines TXn in the first time zone, the second frequency driving is used in the second time zone, the first frequency and the second frequency are different, the first voltage V1 is applied to the first scanning line TX1, the second voltage V2 is applied to the second scanning line TX2, the third voltage V3 is applied to the third scanning line TX3, the fourth voltage V4 is applied to the fourth scanning line TX4, and v4 not equal to v1+v2+v3, v4 not equal to v1+v3, v3 not equal to v1+v2.
3. The capacitive touch driving method according to claim 2, characterized in that: in the formal scanning, a first frequency driving is used for any one scanning line TXn in a first time area, a second frequency driving is used in a second time area, the first frequency and the second frequency are different, a first voltage V1 is applied to a first scanning line TX1, a second voltage V2 is applied to a second scanning line TX2, a third voltage V3 is applied to a third scanning line TX3, a fourth voltage V4 is applied to a fourth scanning line TX4, four different voltages are respectively applied to the four scanning lines as periods, the first voltage V1 to the fourth voltage V4 are continuously applied to the four scanning lines of the next continuous period in sequence, and the scanning of all the scanning lines is completed.
4. A capacitive touch driving method, characterized in that: in the formal scanning, a first frequency driving is used for any one scanning line TXn in a first time region, a second frequency driving is used in a second time region, the first frequency and the second frequency are different, and the capacitance difference Rdx (n-1) of any two adjacent detection lines RXn-1 and RXn meets Rdx (n-1) = (RXn-1-RXn).
5. A transmitting apparatus, comprising:
a signal generator for generating signals of a plurality of frequencies;
a Hadamard encoder for encoding the signal;
the signal generator and the Hadamard encoder are connected with the first mixer and are used for mixing signals with a plurality of frequencies and coded signals;
the digital-to-analog conversion circuit is connected with the first mixer and is used for converting the mixed signals into analog signals;
the first low-pass filter is connected with the digital-to-analog conversion circuit and is used for filtering signals;
and the multiplexer is connected with the first low-pass filter.
6. The transmission apparatus according to claim 5, wherein: the multiplexer is connected to a plurality of drivers.
7. The transmission apparatus according to claim 6, wherein: the driver is connected with the pressurizer.
8. A receiving apparatus, comprising:
a digital controller;
at least one path of transmission device comprises:
an analog front-end circuit connected to the digital controller;
an analog converter connected to the digital controller and the analog front-end circuit, respectively;
the digital controller is connected with the second mixer through a mixing wave regulator, and the analog converter is connected with the second mixer;
and the baseband demodulator is respectively connected with the second mixer and the digital controller.
9. The receiving apparatus according to claim 8, wherein: the digital controller is connected with the mixed wave regulator through a delayer.
10. The receiving apparatus according to claim 8, wherein: the analog front-end circuit comprises a fully differential charge amplifier, a programmable gain amplifier and a second low-pass filter, wherein the fully differential charge amplifier is connected with the second low-pass filter through the programmable gain amplifier, and the second low-pass filter is connected with the analog converter.
11. A touch screen, characterized in that: comprising a transmitting device according to any of claims 5-7 and a receiving device according to any of claims 8-10.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN118678088A (en) * | 2024-06-18 | 2024-09-20 | 义乌毅慧网络科技有限公司 | Multi-network element structure big data processing system |
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| CN104035249A (en) * | 2013-03-05 | 2014-09-10 | 钟钢 | Liquid crystal display device integrating touch function and touch position detecting method thereof |
| CN107300994A (en) * | 2016-04-15 | 2017-10-27 | 乐金显示有限公司 | Drive circuit and the display device for being integrated with touch-screen |
| US20220137776A1 (en) * | 2019-02-26 | 2022-05-05 | Focaltech Electronics (Shenzhen) Co., Ltd. | Touch control method, circuit system, and touch device |
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| CN104035249A (en) * | 2013-03-05 | 2014-09-10 | 钟钢 | Liquid crystal display device integrating touch function and touch position detecting method thereof |
| CN107300994A (en) * | 2016-04-15 | 2017-10-27 | 乐金显示有限公司 | Drive circuit and the display device for being integrated with touch-screen |
| US20220137776A1 (en) * | 2019-02-26 | 2022-05-05 | Focaltech Electronics (Shenzhen) Co., Ltd. | Touch control method, circuit system, and touch device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN118678088A (en) * | 2024-06-18 | 2024-09-20 | 义乌毅慧网络科技有限公司 | Multi-network element structure big data processing system |
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