Touch detection devices and electronic equipment, touch detection methods

Abstract

This invention relates to a touch detection device, an electronic device, and a touch detection method. The touch detection device and method employ coding and decoding to acquire a frame of touch-related data covering n*m capacitive nodes. The n*m ​​coupled signals undergo coding multiple access accumulation processing, common-mode reduction processing, analog-to-digital conversion processing, and decoding processing. Furthermore, by acquiring two consecutive frames of touch-related data and differentially subtracting them, touch distribution information of n*m capacitive nodes is formed, achieving high touch sensitivity. In addition, before differential subtraction, the common-mode analog voltage subtracted by the common-mode reduction processing in the single frame of touch-related data obtained after decoding does not need to be restored, avoiding errors caused by restoration operations, and helping to reduce circuit area and power consumption. The electronic device includes the touch detection device.

Description

Technical Field

[0001] This invention relates to the field of touch control, and more particularly to touch detection devices, electronic devices, and touch detection methods. Background Technology

[0002] Capacitive touch is a commonly used touch technology in smart terminals. This technology attaches a capacitive touch sensor, which senses touch based on changes in capacitance, to a display device (such as an LCD or OLED display) or integrates it within the display device. A capacitive touch sensor typically includes a driving end and a sensing end. The driving end includes multiple driving channels, and the sensing end includes multiple sensing channels. The driving channels and sensing channels intersect to form multiple capacitive nodes. When a conductive object (such as a human body or a stylus) touches the capacitive touch sensor, the touch is sensed by the capacitance change caused by a small amount of charge moving to the capacitive nodes.

[0003] To improve the precision and accuracy of touch sensing, it is necessary to reduce the impact of noise from the human body or other circuits, as well as crosstalk from adjacent rows or columns, on the sensing signal. In one touch detection device, a code sequence is used to encode the driving signal. The code sequence corresponds to the code chips of each driving channel, which are loaded onto the corresponding driving channel at set time intervals. After each sensing channel receives a coupling signal (voltage or voltage change of a capacitor plate), the coupled signal of the capacitor node on that sensing channel is accumulated using a code-encoded multiple access method (CMA), resulting in multiple analog voltage accumulation values. These accumulated analog voltage values ​​are superimposed with a common modulus composed of the code chip data from each driving channel, and this is output as a detection signal (analog voltage signal). An analog-to-digital converter (ADC) converts this analog voltage signal into a digital voltage signal, which is then decoded. For example, an inner product operation is performed on the multiple digital voltage signals associated with each sensing channel and the complete code chip used by each driving channel to generate the touch-related value for each capacitor node. Finally, point reporting is performed, for example, by outputting the data from different sensing channels differentially, and by integrating and restoring the matrix of the differential signals, the touch distribution information of each capacitor node is obtained.

[0004] In the aforementioned touch detection device, after obtaining multiple analog voltage accumulation values ​​through coding and multiple access accumulation, the accumulated analog voltage values ​​may exceed the input signal range of the analog-to-digital converter (ADC) due to the limited input signal range of the ADC, leading to signal oversaturation and reduced touch detection sensitivity. Therefore, it is often necessary to perform a common-mode reduction (or DC reduction) operation on the accumulated analog voltage values ​​to ensure that the analog voltage signal to be converted falls within the input range of the ADC. However, since the common-mode value corresponding to each coding may be different, if the same DC value is subtracted from each coding operation, the resulting touch detection result after decoding will be inaccurate, reducing touch sensitivity. Improving the accuracy of the decoding result after coding accumulation in the touch detection device is a problem urgently needing to be solved in this field. Summary of the Invention

[0005] This invention provides a touch detection device and a touch detection method. The driving signal is encoded using a code sequence at the driving end, and a touch detection signal is acquired at the sensing end. Furthermore, it eliminates the need for common-mode reduction and restoration operations, resulting in high touch sensitivity and low power consumption. This invention also provides an electronic device including the aforementioned touch detection device.

[0006] On one hand, the present invention provides a touch detection device for detecting capacitance changes in n*m capacitor nodes formed by m driving channels and n sensing channels, where m and n are positive integers. The touch detection device includes a frame processing module and a reporting calculation module. The frame processing module is used to load coding driving signals to each driving channel in each coding cycle, and to acquire n*m ​​coupling signals formed at each capacitor node through each sensing channel. After coding multiple access accumulation processing, common mode reduction processing, analog-to-digital conversion processing, and decoding processing, a frame of touch-related data covering n*m capacitor nodes is obtained. The common mode reduction processing is used to ensure that the accumulated values ​​of the n analog voltages after coding multiple access accumulation processing are within the input range required by the analog-to-digital conversion processing. The reporting calculation module is used to acquire the touch-related data of two consecutive frames and perform differential subtraction on the two frames of touch-related data to form touch distribution information of n*m capacitor nodes.

[0007] Optionally, before the reporting calculation module performs differential subtraction on the two frames of touch-related data, the common-mode analog voltage amount subtracted by the common-mode reduction processing in each frame of touch-related data is not restored.

[0008] Optionally, the frame processing module includes:

[0009] The coding unit is used to generate code chips for each of the driving channels, and to generate m coding driving signals for each coding operation based on the code chips.

[0010] The coding accumulation unit is used to acquire n*m ​​coupling signals formed at each capacitor node of m driving channels through each of the sensing channels, and to perform coding multiple access accumulation on the coupling signals of m capacitor nodes on each of the n sensing channels and the m coding driving signals for each coding to obtain the n analog voltage accumulation values.

[0011] The common-mode reduction unit is used to process the n accumulated analog voltage values, subtract the common-mode analog voltage amount that exceeds the input range required by the analog-to-digital conversion process, and generate n analog voltage signals to be decoded.

[0012] An analog-to-digital conversion unit is configured to convert n analog voltage signals to be decoded into n digital voltage signals to be decoded; and,

[0013] The decoding unit is used to decode based on the n digital voltage signals to be decoded and the chips used by the m driving channels to generate the touch-related values ​​of the n*m ​​capacitive nodes in the one frame of touch-related data.

[0014] Optionally, the coding and accumulation unit performs coding k times to form n*k accumulated analog voltage values. The decoding unit multiplies and adds the corresponding n*k digital voltage signals to be decoded and the k*m chips used by the driving channels to generate the touch-related values ​​of n*m capacitor nodes in the one frame of touch-related data, where k is a positive integer.

[0015] Optionally, the common-mode reduction unit includes at least one current source disposed at the output node of each of the n sensing channels, so as to make the accumulated value of the n analog voltages within the input range required by the analog-to-digital conversion process by means of current extraction or current addition.

[0016] Optionally, the common-mode reduction unit and the coding accumulation unit include:

[0017] An integrator is used to integrate the charge of the output node of each of the n sensing channels to generate the n analog voltage signals to be decoded that do not exceed the input range required by the analog-to-digital conversion process, and input them to the analog-to-digital conversion unit.

[0018] Optionally, the coding accumulation unit performs k coding operations, and the common-mode analog voltage is determined by the common-mode value accumulated from the m coding drive signals during each coding operation, where k is a positive integer.

[0019] Optionally, the two consecutive frames are touch-related data in a no-touch frame and touch-related data in a touch frame, respectively.

[0020] On one hand, the present invention provides a touch detection method, executed by a touch chip, for detecting capacitance changes in n*m capacitor nodes formed by m driving channels and n sensing channels, where m and n are positive integers. The touch detection method includes:

[0021] In each coding cycle, a coding drive signal is loaded onto each of the driving channels, and n*m coupling signals formed at each of the capacitor nodes are acquired through each sensing channel. After coding multiple access accumulation processing, common-mode reduction processing, analog-to-digital conversion processing, and decoding processing, a frame of touch-related data covering n*m capacitor nodes is obtained. The common-mode reduction processing is used to ensure that the accumulated n analog voltage values ​​after coding multiple access accumulation processing are within the input range required by the analog-to-digital conversion processing.

[0022] The touch-related data of two consecutive frames are acquired, and the touch-related data of the two frames are differentially subtracted to form the touch distribution information of n*m capacitive nodes.

[0023] On one hand, the present invention provides an electronic device including the above-described touch detection device.

[0024] In the touch detection device provided by this invention, the frame processing module uses coding and decoding to acquire a frame of touch-related data covering n*m capacitor nodes. The n*m ​​coupled signals undergo coding multiple access accumulation processing, common-mode reduction processing, analog-to-digital conversion processing, and decoding processing. The common-mode reduction processing ensures that the accumulated values ​​of the n analog voltages after coding multiple access accumulation are within the input range required by the analog-to-digital conversion processing. The reporting calculation module acquires two consecutive frames of touch-related data and performs differential subtraction on the two frames to form touch distribution information for n*m capacitor nodes, achieving high touch sensitivity. Furthermore, before differential subtraction, the common-mode analog voltage subtracted by the common-mode reduction processing in the single frame of touch-related data obtained after decoding does not need to be restored, avoiding errors caused by restoration operations, and helping to reduce circuit area and power consumption.

[0025] The touch detection method and electronic device provided by this invention have similar concepts to the touch detection device described above, and therefore have similar advantages. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the touch detection device according to an embodiment of the present invention.

[0027] Figure 2 This is a hardware connection diagram of the touch detection device according to an embodiment of the present invention.

[0028] Figure 3This is a schematic diagram of the frame processing module performing coding, coding multiple access accumulation and decoding in an embodiment of the present invention.

[0029] Figure 4 This is a flowchart illustrating the touch detection method according to an embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 100 - Touch detection device; 110 - Frame processing module; 120 - Reporting point calculation module; 111 - Coding unit; 112 - Coding accumulation unit; 113 - Common mode reduction unit; 114 - Analog-to-digital conversion unit; 115 - Decoding unit; 212 - Current source; 214 - Integrator. Detailed Implementation

[0032] The touch detection device, electronic device, and touch detection method of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0033] This invention relates to a touch detection device, which detects capacitance changes in n*m capacitive nodes formed by m driving channels and n sensing channels, where m and n are positive integers. The touch detection device is, for example, a touch chip or other device capable of performing its function (such as a capacitive touch sensor or touch detection circuit). The driving channels include, for example, driving electrodes attached to or built into a display device (such as a liquid crystal display or an organic light-emitting diode display), and the sensing channels include sensing electrodes disposed opposite to the driving electrodes. The m driving channels can be connected to a touch driving device and a coding unit to apply a coded driving signal to the driving electrodes. This coded driving signal is coupled to the corresponding sensing electrode, i.e., a coupling signal is generated in the n sensing channels. Touch detection is achieved by processing the coupling signal.

[0034] Figure 1 This is a schematic diagram of the structure of the touch detection device according to an embodiment of the present invention. Figure 2 This is a hardware connection diagram of the touch detection device according to an embodiment of the present invention. (Refer to...) Figure 1 and Figure 2The touch detection device 100 of this embodiment includes a frame processing module 110 and a reporting calculation module 120. The frame processing module 110 loads a coding drive signal onto each of the driving channels in each coding cycle, and acquires n*m coupling signals formed at each of the capacitor nodes through each sensing channel. After coding multiple access accumulation processing, common-mode reduction processing, analog-to-digital conversion processing, and decoding processing, it obtains a frame of touch-related data covering n*m capacitor nodes. The common-mode reduction processing ensures that the accumulated n analog voltage values ​​after coding multiple access accumulation processing are within the input range required by the analog-to-digital conversion processing. The reporting calculation module 120 acquires the touch-related data from two consecutive frames and performs differential subtraction on the two frames of touch-related data to form touch distribution information for n*m capacitor nodes.

[0035] Figure 3 This is a schematic diagram illustrating the frame processing module's operations of coding, coding multiple access accumulation, and decoding according to an embodiment of the present invention. The following is in conjunction with... Figures 1 to 3 Taking a set number of driving channels and sensing channels as an example, the structure of the frame processing module 110 in a specific embodiment of the present invention and its implementation of coding, coding multiple access accumulation, common mode reduction, analog-to-digital conversion and decoding processes are explained.

[0036] The frame processing module 110 may include a coding unit 111, which generates code chips applicable to m driving channels (denoted by Tx) and generates m coding driving signals for each coding operation based on the code chips. As an example, the number of driving channels is 21 (i.e., m = 21), and the number of sensing channels (denoted by Rx) is 42 (i.e., n = 42). The coding unit 111 uses m-code coding, but is not limited to this. In this embodiment of the invention, the code chips used to code each driving channel can be various PN (pseudorandomnoise) codes or orthogonal codes, such as Walsh codes. Taking m-code as an example, since the code length of m-code is usually (2y-1) bits (y is a positive integer), 21 driving channels require 21 m-codes. For example: if a 31-bit m-code is used, there are 31 31-bit m-codes, requiring one complete coding cycle (31 times in total); if a 15-bit m-code is used, there are 15 15-bit m-codes, requiring two separate coding cycles for each of the 21 channels (for example, first performing 15 complete coding cycles for channels 1-15, then selecting 5 from these 15 m-codes to perform 15 complete coding cycles for the remaining channels 16-21). The following example illustrates the process of using a 31-bit m-code and coding 31 times (one complete coding cycle).

[0037] Reference Figure 3During the coding process, the frame processing module 110 records the 31 coding operations at times t1, t2, ..., t31. At time t1, the chip vectors configured for the 1st to 21st driving channels are m11, m21, ..., m211, respectively. At time t2, the chip vectors configured for the 1st to 21st driving channels are m12, m22, ..., m212, and so on. At time t31, the chip vectors configured for the 1st to 21st driving channels are m11, m22, ..., m212, respectively. 31 m2 31 ...and m21 31 Each chip vector (e.g., m21) 31 The value can be either 1 or -1. The complete chip sequence for each of the 21 driving channels is a combination of 31 coding vectors, denoted as M1, M2, ..., M20 and M21 respectively. For example, the chip sequence of the first driving channel (Tx1) is M1 = (m11, m12, ..., m1...). 31 When the driving channel loads coding data, the driving signal of each driving channel is encoded by the corresponding chip sequence. The coding driving signal applied to the driving electrode each time is a combination of the chip vectors on the m (m=21) driving channels at that moment. For example, the coding driving signal at t1 is (m11, m21, ..., m211), the coding driving signal at t2 is (m12, m22, ..., m212), and so on. The coding driving signal at time t31 is (m11, m21, ..., m211). 31 m2 31 ...,m21 31 ).

[0038] After capacitive coupling, n sensing channels act as receiving ends. At the sensing channel port (Rx port), the acquired coupled data is first processed by coding multiple access accumulation. The frame processing module 110 may include a coding accumulation unit 112. The coding accumulation unit 112 is used to acquire n*m ​​coupling signals formed at each capacitor node of m driving channels through each sensing channel, and to perform coding multiple access accumulation on the coupling signals of the m capacitor nodes on each of the n sensing channels and the m (m=21) coding driving signals for each coding, to obtain n analog voltage accumulation values. For example, when the Rx1 channel is coded at t1, the 21 coupling signals corresponding to Rx1 are multiplied and added with the coding driving signals (m11, m21, ..., m211) of t1. The sum of the chip vectors when coding the m driving channels each time is the common mode of that coding.

[0039] Specifically, refer to Figure 3Before performing the coding multiple access accumulation, the frame processing module 110 first acquires n*m coupling signals formed at each capacitor node of the m driving channels through each of the sensing channels, and then codes and accumulates the coupling voltage data of the m capacitor nodes on each of the n sensing channels. Taking the voltage data of the coupling signals acquired by the sensing channels as 9V as an example, and taking mt... i Let represent the chip vector of the i-th driving channel (i = 1, 2, ..., or 21) during one coding iteration. Then, the multiple access accumulation result of the 21 capacitor nodes on the same sensing channel during that coding iteration is expressed as: Each coding operation yields 42 (n=42) analog voltage accumulation values ​​from the 42 sensing channels. Using this method, after 31 coding operations, a 42-row, 31-column data set is obtained. The first row of data represents the multiple access accumulation results of the 21 capacitor nodes on the first sensing channel (Rx1) at times t1, t2, ..., t31, denoted as C11, C21, ..., C311 respectively. The second row represents the multiple access accumulation results of the 21 capacitor nodes on the second sensing channel (Rx2) at times t1, t2, ..., t31, denoted as C12, C22, ..., C312 respectively, and so on. For simplicity, the matrix obtained through coding multiple access accumulation (in this example, a 42-row, 31-column matrix) is called the coding accumulation matrix. In the coding accumulation matrix, the number of rows is the number of sensing channels n, and the number of columns is the number of coding attempts k (k is a positive integer), meaning the coding accumulation matrix is ​​an n*k (n rows, k columns) matrix. Each column of data corresponds to the time of each coding attempt. The 42 (n=42) sensing channels obtain 42 (n=42) analog voltage accumulation values. The data in the first column are the results of coding multiple access accumulation of the 21 (m=21) capacitor nodes of the 42 sensing channels (Rx1~Rx42) at time t1 with the coding drive signal at time t1, denoted as C11, C12, ..., C1 42 The second column contains the results of coding multiple access accumulation of the 21 (m=21) capacitor nodes of the 42 sensing channels (Rx1~Rx42) at time t2 with the coding drive signal at time t2, denoted as C21, C22, ... and C2 42 And so on.

[0040] After the coding multiple access accumulation process, in order to avoid the value of the input analog voltage signal during analog-to-digital conversion exceeding the input range of the analog-to-digital conversion unit 114, and to prevent the oversaturation of the analog voltage signal from affecting the touch sensitivity, the frame processing module 110 further processes the analog voltage accumulation value corresponding to each element in the coding accumulation matrix according to a set range (this set range is based on the input range required by the analog-to-digital conversion unit 114, and here it is set to the input range required by the analog-to-digital conversion process). This reduces the analog voltage accumulation value that exceeds the set range, and is called common-mode reduction processing (or DC reduction processing). Specifically, the frame processing module 110 may include a common-mode reduction unit 113, which processes the n analog voltage accumulation values ​​obtained by the coding accumulation unit 112, subtracts the common-mode analog voltage amount that exceeds the input range required by the analog-to-digital conversion unit 114, and generates n analog voltage signals to be decoded.

[0041] Reference Figure 2 In one embodiment, Figure 1 The common-mode reduction unit 113 may include at least one current source 212 disposed at the output node of each of the sensing channels, to reduce current or increase current (current direction as shown in the figure). Figure 2 The common-mode analog voltage exceeding the set range is subtracted using the method shown in I1 or I2 in the diagram, thereby ensuring that the accumulated values ​​of the above n analog voltages are within the input range required by the analog-to-digital conversion processing. Using the current source 212, the common-mode reduction unit 113, based on the voltage-capacitance formula V = i*t / C (V is the common-mode analog voltage to be subtracted, i is the current, t is the time, and C is the capacitance value of the integrating capacitor), can select different currents i to set different subtraction DC values. The n*k subtraction DC values ​​constitute a common-mode reduction matrix (or subtraction DC matrix), which is an n*k (n rows, k columns) matrix. This matrix processes the accumulated analog voltage values ​​of each element in the above-mentioned coding accumulation matrix (n rows, k columns) to subtract the analog voltage exceeding the set range. In one embodiment, the values ​​in each column and row of the subtractive DC matrix may be the same; this value is called the "common-mode analog voltage." This value in each column of the subtractive DC matrix is ​​related to the common-mode voltage at each coding iteration (i.e., the sum of the chip vectors of the m driving channels at that coding moment). In other embodiments, the values ​​in each column and row of the subtractive DC matrix may be different. This is because when a touch action occurs on a certain sensing channel, the response values ​​in some rows of each column may be smaller. However, whether the values ​​in each column and row of the DC matrix are the same does not affect the value obtained by subtracting the decoded two frames as described in the embodiments of this invention.

[0042] In addition, the common-mode reduction unit 113 may also include, for example: Figure 2 The integrator 214 shown can... Figure 2The charge quantity processed by at least one current source shown is integrated to obtain the analog voltage signal to be decoded. It is worth noting that, when configuring the hardware of the touch detection device in this embodiment of the invention, the integrator 214 can also be used to implement... Figure 1 The coding accumulation unit 112 shown is used to implement the aforementioned coding accumulation operation. That is, the integrator 214 can be used to implement part of the functions of the common-mode reduction unit 113 and the coding accumulation unit 112. In this embodiment, the integrator 114 is used to integrate the charge of the output node of each of the n sensing channels to generate n analog voltage signals to be decoded that do not exceed the set range and input them to the analog-to-digital conversion unit 114. In another embodiment, the charge of the output node of each of the n sensing channels can be integrated using its own independent integrator to generate n analog voltage signals to be decoded that do not exceed the set range and input them to the analog-to-digital conversion unit 114.

[0043] A switch (S1) is provided between the current source 212 and the integrator 214. The integrator 214 includes an operational amplifier with a first input connected to ground and a second input connected to the output of the current source 212 (one end of S1), and also includes an integrating capacitor (Cf) disposed between the second input of the operational amplifier and the output node of the current source 212. The integrator 214 also includes a switch (rst) disposed between the second input and the output terminal of the operational amplifier. Using the current source 212, the analog voltage exceeding the set range is subtracted by extracting current (reducing charge) or adding current (adding charge). Specifically, by extracting the charge in the integrating capacitor of the integrator 214, the charge amount changes, thereby changing the voltage output of the integrator 214, thus achieving common-mode reduction. Specifically, each analog voltage signal to be decoded output by the integrator 214 can be obtained according to the following formula:

[0044] ΔVout=-N*ΔVin*Cm / Cf+d*Qdc / Cf,

[0045] Where N is the common mode of each coding (i.e., the sum of the chip vectors of the m driving channels at the coding moment), ΔVin is the coupling voltage data of the m capacitor nodes on each sensing channel (e.g., 9V), Cm is the capacitance value of the aforementioned capacitor node, Cf is the integration capacitance value in the integrator 214, d is the subtracted DC value, and Qdc is the unit charge. Different d values ​​(i.e., subtracted DC values) can be determined according to different N values ​​(i.e., the common mode of coding). The analog voltage signal ΔVout to be decoded output by the integrator 214 is adjusted to the working range of the subsequent analog-to-digital conversion unit 114.

[0046] Reference Figure 1 and Figure 2The frame processing module 110 may include an analog-to-digital converter (ADC) unit 114, which converts the accumulated analog voltage values ​​that do not exceed a set range into digital signals; that is, it converts the aforementioned n analog voltage signals to be decoded into n digital voltage signals to be decoded. The ADC unit 114 has a certain input voltage range. Within this range, the n analog voltage signals input to the ADC unit 114 are converted into n digital voltage signals to be decoded within the corresponding range. The ADC unit 114 may employ a structure disclosed in the art.

[0047] Reference Figure 2 The analog-to-digital converter (ADC) 114 includes, for example, a programmable gain amplifier (PGA) and an analog-to-digital converter (ADC). Since the analog voltage signal to be decoded input to the ADC 114 undergoes common-mode reduction processing, it will not exceed the input range of the ADC 114, thus avoiding the impact of voltage signal oversaturation on touch sensitivity. The 42 (n=42) digital voltage signals output from the ADC 114 are used for decoding to obtain the touch-related values ​​of each capacitive node. Specifically, 31 (k=31) coding operations are performed to form... Figure 3 The data set of 42 rows and 31 columns (n ​​rows and k columns, where k is the number of times the code is applied) shown above (i.e., a code accumulation matrix) can be obtained as a 42-row and 31-column digital matrix to be decoded after common-mode reduction and analog-to-digital conversion. In this matrix, each element is the digital voltage signal to be decoded obtained by reducing the common-mode value and performing analog-to-digital conversion on the accumulated analog voltage value at that position.

[0048] Reference Figure 1 and Figure 2 The frame processing module 110 may include a decoding unit 115, which is used to decode n (for example, n=42) digital voltage signals to be decoded and m (for example, m=21) chips used by the driving channel to generate the touch-related values ​​of the above n*m ​​capacitive nodes. Figure 3 The coding accumulation matrix shown is obtained from 31 (k=31) coding accumulation operations. After common-mode subtraction and analog-to-digital conversion, this matrix yields a 42x31 (n*k, n=42, k=31) matrix of digital data to be decoded. During decoding, the data in each row of this 42x31 (n*k, n=42, k=31) matrix is ​​multiplied by the chip sequences of the 21 (m=21) driving channels (i.e., k*m chip vectors) to obtain the touch correlation value of each capacitive node on each sensing channel. (Refer to...) Figure 3 For the i-th driving channel (i = 1, 2, ..., or 21), the decoded data (j = 1, 2, ..., or 42) of the j-th sensing channel can be represented as: k represents the number of times the code is applied.

[0049] To further clarify the above coding and decoding process, the following simplified explanation describes the coding and decoding process for 2 driving channels (m=2) and 4 sensing channels (n=4). In this embodiment, driving channel T... X The applied voltage data can be expressed as The two columns of data correspond to two driving channels. Taking a total of 3 coding operations (k=3) as an example, the chip vector corresponding to the driving channel of the left column voltage is (1, 1, -1), and the chip vector corresponding to the driving channel of the right column voltage is (-1, 1, 1). Here, 1 corresponds to a rising edge, indicating that the integration ranges from -3V to 6V, i.e., the corresponding encoded data is 9V; -1 corresponds to a falling edge, indicating that the integration ranges from 9V to -3V, i.e., the corresponding encoded data is -9V. At the receiving end (sensing channel) R... X First, the above process is used to perform multi-address coding and accumulation, resulting in the following 4-row, 3-column data set: The left, middle, and right columns of data represent the accumulated values ​​corresponding to the three coding operations (at time t1, 9-9=0; at time t2, 9+9=18; at time t3, -9+9=0). After common-mode reduction and analog-to-digital conversion, decoding is performed, and the inner product of the multiple access accumulation vector and the chip vector is calculated. For example, the inner product of (0, 18, 0) and (1, 1, -1) is used as the decoding data for the first sensing channel coupled to the driving channel corresponding to the voltage in the left column. The specific calculation process is: 0*1+18*1+0*(-1)=18, thus obtaining a 4-row, 2-column decoded data group.

[0050] The frame processing module 110 described above can perform the above-mentioned coding processing, coding multiple access accumulation processing, common mode reduction processing, and analog-to-digital conversion processing within each frame data processing time to obtain a frame of touch-related data covering n*m capacitive nodes. The touch-related data of each frame can be represented by an n*m matrix, where each row corresponds to a sensing channel, each column corresponds to a driving channel, and the element located at the intersection of the row and column represents the touch-related value of the capacitive node at the intersection of the corresponding sensing channel and driving channel.

[0051] The common-mode reduction processing described above involves subtracting common-mode analog voltage in k coding iterations, which is related to the common-mode amount in that coding iteration (i.e., the sum of the chip vectors when coding m driving channels). Therefore, the amount of common-mode analog voltage subtracted in each coding iteration may be different. After conversion to a digital voltage signal by an analog-to-digital converter and before decoding, it is often necessary to restore the subtracted common-mode data (adding back the subtracted portion) before decoding. Since common-mode reduction is implemented using analog quantities before analog-to-digital conversion, and the restoration process is performed after analog-to-digital conversion, the restoration operation requires first converting the subtracted common-mode analog voltage into a digital quantity through calculation, and then adding it to the digital voltage signal output by the analog-to-digital converter. In one embodiment of the present invention, single-frame touch-related data can be further processed to obtain the touch distribution information of n*m capacitive nodes. For example, data from different sensing channels can be output differentially, and the touch distribution information of n*m capacitive nodes can be obtained by integrating and restoring the matrix of the differential signal. Furthermore, in this technology, if common-mode reduction processing is used when obtaining single-frame touch-related data, before processing the single-frame touch-related data to generate touch distribution information for n*m capacitor nodes, the analog voltage amount subtracted by the common-mode reduction processing needs to be converted into a digital voltage amount and added to the single-frame touch-related data. However, the inventors of this invention have discovered through research that this common-mode reduction and restoration process has the following problems: the digital amount added in the restoration operation and the digital voltage signal obtained by the analog-to-digital converter may have a large error, resulting in an inaccurate digital voltage signal after restoration, which will reduce touch sensitivity. In addition, performing this restoration operation requires setting an adder or subtractor between the analog-to-digital converter and the decoding unit to perform multi-bit logic operations on a large array, which will increase the circuit area and power consumption. To avoid the errors introduced by this restoration process, reduce the circuit area, and reduce power consumption, another embodiment of the touch detection device of this invention does not obtain the touch distribution information of n*m capacitor nodes through single-frame touch-related data, but uses two frames of data for operation.

[0052] Specifically, refer to Figure 1The touch detection device of this embodiment includes a reporting calculation module 120. The reporting calculation module 120 is used to acquire the touch-related data of two consecutive frames and perform differential subtraction on the two frames of touch-related data. Specifically, it subtracts two elements at the same position in the two frames of touch-related data to obtain the touch distribution information of the capacitive nodes at the same position. For a single frame of touch-related data in the form of an n*m matrix, subtracting the two frames can form the touch distribution information of n*m capacitive nodes. The reporting calculation module 120 can be implemented using hardware circuitry or software. For example, in one embodiment, the reporting calculation module 120 includes a processor, and the process of differential subtraction of the two frames of touch-related data by the reporting calculation module 120 is implemented by the processor using software. It is worth noting that in one embodiment, the two frames for differential subtraction can be a frame without touch operation and a frame with touch operation, respectively. In another embodiment, the two frames can also be two adjacent consecutive frames, and both can be frames with touch operation.

[0053] Preferably, in the two frames of touch-related data acquired and differentially subtracted by the reporting calculation module 120, the analog voltage amount subtracted due to the common-mode reduction processing is not restored. That is, before the reporting calculation module performs differential subtraction on the two frames of touch-related data, the common-mode analog voltage amount subtracted by the common-mode reduction processing in each frame of touch-related data is not restored. Experiments show that, for the receiving end, the signal distribution obtained by using the non-common-mode reduction restoration method of the present invention (i.e., after obtaining the coding accumulation matrix and performing common-mode reduction and analog-to-digital conversion, the subtracted common-mode analog voltage is not restored, but the digital matrix to be decoded obtained by the above analog-to-digital conversion process is directly used to decode and obtain two frames of touch-related data, and then the difference between the two frames of touch-related data is calculated) and the two frames of data obtained by directly collecting the analog voltage signals of each voltage node of each sensing channel (without coding multiple access accumulation), and then calculating the difference between the two frames of data, is consistent. This indicates that the non-common-mode reduction restoration method of the present invention does not affect the touch sensitivity, so restoration processing is not required. This avoids the error caused by the restoration operation, ensures high touch sensitivity, and since the readout circuit does not need to set up a restoration module, it helps to reduce the circuit area and reduce power consumption.

[0054] This invention also relates to a touch detection method for detecting capacitance changes in n*m capacitor nodes formed by m driving channels and n sensing channels, where m and n are positive integers. This touch detection method can be implemented by a touch chip, which may include, for example, a digital signal processing (DSP) module or a microprocessor (MCU) to execute the touch detection method. Figure 4This is a schematic flowchart of the touch detection method according to an embodiment of the present invention. (Refer to...) Figure 4 The touch detection method mainly includes the following first step and second step:

[0055] In the first step S1, a coding drive signal is loaded into each of the driving channels in each coding cycle, and n*m coupling signals formed at each of the capacitor nodes are obtained through each sensing channel. After coding multiple access accumulation processing, common mode reduction processing, analog-to-digital conversion processing and decoding processing, a frame of touch-related data covering n*m capacitor nodes is obtained. The common mode reduction processing is used to ensure that the n analog voltage accumulation values ​​after coding multiple access accumulation processing are within the input range required by the analog-to-digital conversion processing.

[0056] The second step S2 involves acquiring the touch-related data from two consecutive frames and subtracting the two frames of touch-related data to form touch distribution information for n*m capacitive nodes.

[0057] The touch detection method and touch detection device of the present invention adopt a general concept, and the above description of the touch detection device of the embodiments of the present invention also applies to the touch detection method. In a preferred embodiment of the touch detection method, before differential subtraction of two frames of touch-related data, the analog voltage amount subtracted by the common-mode reduction processing in each frame of touch-related data is not restored, in order to avoid errors caused by the restoration operation, ensure high touch sensitivity, and since the readout circuit does not need to include a restoration module, it helps to reduce circuit area and power consumption. The following specific experimental data illustrates that the method of not performing common-mode reduction restoration in the embodiments of the present invention does not affect touch sensitivity.

[0058] As an example, assuming m=4, n=4, and k=4, the touch distribution information of the 16 capacitive nodes composed of 4 driving channels (denoted as Tx1, Tx2, Tx3, Tx4) and 4 sensing channels (denoted as Rx1, Rx2, Rx3, Rx4) is analyzed through 4 rounds of coding. The code chip data (i.e., coding matrix) from the 4 rounds of coding is as follows:

[0059]

[0060] In this m*k (m rows, k columns, 4*4) coding matrix, each row contains the chip data for each driving channel. A complete chip data is coded at times t1, t2, t3, and t4 to represent the driving signals of the corresponding driving channel. The sum of the chip vectors for each of the four driving channels at each time step is the common modulus of that coding step. Therefore, in this coding matrix, the common modulus of the four coding steps at times t1, t2, t3, and t4 are -2, 2, 2, and 2, respectively. The value of the common modulus reduction processing is related to this common modulus. It can be seen that the common modulus of each column (at different times) in the coding matrix can be different.

[0061] Using the aforementioned coding matrix, after performing four coding operations (k=4, assuming four coding operations per complete coding cycle) on all driving channels, at the receiving end, the analog voltage values ​​of the capacitor nodes of each touch capacitor are obtained through each sensing channel. This yields a frame of n*m (n rows and m columns, here 4*4) touch-related data. This frame of touch-related data is the original touch data. The difference between two adjacent frames of original touch data reflects the difference in the touch signal, thus reflecting the distribution of the touch signal. Here, a frame of original touch data obtained without a touch signal (untouch) is denoted as uncoded original data matrix 1, and a frame of original touch data obtained with a touch signal (touch) is denoted as uncoded original data matrix 2. Each row represents a different sensing channel, and each column represents a different driving channel, as shown in the table below. It is worth noting that in the aforementioned... Figure 3 In the embodiments, it is assumed that the voltage data of the coupling signal collected by the sensing channel is 9V. However, the touch detection method of the present invention does not need to be limited to the case that n*m original touch data are the same. The simulated voltage values ​​of the capacitor nodes of each touch capacitor in the uncoded original data matrices 1 and 2 shown here are different.

[0062] (Original data matrix 1 without censoring)

[0063]

[0064] (Original data matrix 2 without censoring)

[0065]

[0066] The aforementioned coding accumulation operation is performed as follows: For the aforementioned uncoded original data matrix 1 and uncoded original data matrix 2, the coupling signals of the four (m=4) capacitor nodes on each of the four (n=4) sensing channels (R1, R2, R3, R4) are accumulated with the four (m=4) coding drive signals for each coding (i.e., one column of the aforementioned coding matrix, with different columns for t1 to t4), resulting in four (n=4) analog voltage accumulation values ​​as the values ​​of one column of the coding accumulation matrix. The coding multiple access accumulation of the four coding operations from t1 to t4 yields the values ​​of the four columns of the coding accumulation matrix, thus obtaining the coding accumulation matrix 1 and coding accumulation matrix 2 as shown below, respectively, under the conditions of no touch signal and with touch signal. The elements in the first column of the coding accumulation matrix 1 are obtained by multiplying the data of Rx in the uncoded original data matrix 1 (one row of the uncoded original data matrix 1) with the corresponding chips of each different Tx at coding time t1 (i.e., one column of the coding matrix above) and then summing them. Similarly, the elements in the first column of the coding accumulation matrix 2 are obtained by multiplying the data of Rx in the uncoded original data matrix 2 (one row of the uncoded original data matrix 2) with the corresponding chips of each different Tx at coding time t1 (i.e., one column of the coding matrix above) and then summing them. In coding accumulation matrices 1 and 2, each row represents a different sensing channel, each column represents a different coding time, and each element in the matrix is ​​the accumulated analog voltage value after coding multiple access accumulation processing. Therefore, the coding accumulation matrix is ​​an n*k (n rows, k columns, here 4*4) matrix.

[0067] (Accumulated Captioning Matrix 1)

[0068]

[0069] (Accumulated Matrix 2)

[0070]

[0071] Next, common-mode reduction processing is performed on both coding accumulation matrix 1 and coding accumulation matrix 2. The common-mode reduction matrix shown below is used to process the elements in the coding signal matrix. As described above, common-mode reduction can be achieved by applying or removing current from the integrating capacitor. Therefore, the elements of the common-mode reduction matrix can be set as the common-mode analog voltage to be subtracted. The common-mode reduction unit 113 can select different currents i according to i*t = C*V to achieve the common-mode analog voltage to be subtracted from each element in the common-mode reduction matrix. The setting of each element in the common-mode reduction matrix is ​​related to the common-mode quantity of the chip. For example, in the coding matrix shown above, the common modulus of the four coding operations at times t1, t2, t3, and t4 are -2, 2, 2, and 2, respectively. Therefore, theoretically, the subtraction DC value of each row element in each column of the common modulus reduction matrix should be the same. However, since the response value of some rows of capacitor nodes on each drive channel may be smaller when there is a touch on a certain sensing channel, the subtraction DC value of each row element in each column of the common modulus reduction matrix may also be different.

[0072] (Decreased Common Mode Matrix)

[0073]

[0074] Using this common-mode reduction matrix, the above-mentioned coding accumulation matrix 1 is processed by common-mode reduction to obtain a common-mode reduction coding matrix 1, and the above-mentioned coding accumulation matrix 2 is processed by common-mode reduction to obtain a common-mode reduction coding matrix 2, as shown below.

[0075] (Common Mode Reduction Coding Matrix 1)

[0076]

[0077] (Common Mode Reduction and Coding Matrix 2)

[0078]

[0079] Next, using the aforementioned coding matrices, the common-mode reduction coding matrices 1 and 2 are decoded. Here, the method described earlier of taking the inner product of each row of data with the chip vector of each driving channel is employed. The common-mode reduction coding matrices 1 and 2, like the coding accumulation matrix, are n*k (n rows, k columns, here 4*4) matrices. The decoding operation involves multiplying and adding the n*k digital voltage signals to be decoded from the common-mode reduction coding matrix with the k*m chips used by the driving channels (i.e., a k-row, m-column matrix composed of the chip sequences of the m driving channels). After decoding, decoding matrix 1 is obtained from common-mode reduction coding matrix 1, and decoding matrix 2 is obtained from common-mode reduction coding matrix 2.

[0080] (Decoding Matrix 1)

[0081]

[0082] (Decoding Matrix 2)

[0083]

[0084] Decoding matrix 1 and decoding matrix 2 are two frames of touch-related data corresponding to the aforementioned original uncoded original data matrix 1 and uncoded original data matrix 2, respectively. Here, using the method described in the embodiment of the present invention, decoding matrix 1 and decoding matrix 2 are differentially subtracted, and the resulting touch distribution information of 4*4 capacitive nodes is shown in the coding difference matrix below.

[0085] (Differential matrix for encoding)

[0086]

[0087] To verify the accuracy of the touch distribution information reflected by the masked difference matrix, the original unmasked original data matrix 1 and the unmasked original data matrix 2 were also subtracted by difference, resulting in the original unmasked difference matrix shown below.

[0088] (Original uncoded difference matrix)

[0089]

[0090] Comparing the coded difference matrix and the original uncoded difference matrix above, it can be seen that the touch distribution information they represent is consistent. This result indicates that, even without restoration after common-mode reduction processing, the difference signal distribution of the two frames of data obtained by direct decoding using the touch display device or touch display method of the preferred embodiment of the present invention is consistent with the difference signal distribution of the original two frames of data. Therefore, it does not affect the touch sensitivity. Moreover, this avoids the error caused by the restoration operation, ensuring a high touch sensitivity. Furthermore, since the readout circuit does not need to set up a restoration module, it helps to reduce the circuit area and power consumption.

[0091] This invention relates to an electronic device, which includes the touch detection device described above in this invention. The electronic device is, for example, a display with touch and display functions. The display has a screen and a touch layer disposed on the screen. Touching the touch layer changes the displayed content. The screen can use OLED, LED, or LCD display technologies. The electronic device can be a mobile phone, personal computer, laptop computer, personal digital assistant (PDA), smartwatch, media player, navigation device, game console, tablet computer, wearable device, access control system, keyless entry system, or keyless start system for automobiles, etc.

[0092] The touch detection device, touch detection method, and electronic device provided by this invention employ coding and decoding to acquire a frame of touch-related data covering n*m capacitive nodes. The n*m ​​coupled signals undergo coding multiple access accumulation processing, common-mode reduction processing, analog-to-digital conversion processing, and decoding processing. Furthermore, by acquiring two consecutive frames of the touch-related data and differentially subtracting them, touch distribution information for the n*m ​​capacitive nodes is formed, achieving high touch sensitivity. In addition, before differential subtraction, the common-mode analog voltage subtracted by the common-mode reduction processing in the single frame of touch-related data obtained after decoding does not need to be restored, avoiding errors caused by the restoration operation, which helps reduce circuit area and power consumption.

[0093] The methods and structures in this embodiment are described in a progressive manner. The later methods and structures are described in detail to highlight the differences from the earlier methods and structures. Relevant parts can be understood by referring to them.

[0094] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A touch detection device for detecting a capacitance change of n*m capacitive nodes formed by m driving channels and n sensing channels, m and n being positive integers, characterized in that, The touch detection device includes: A frame processing module is used to load coding drive signals to each of the driving channels in each coding cycle, and to acquire n*m ​​coupling signals formed at each of the capacitor nodes through each sensing channel. After coding multiple access accumulation processing, common-mode reduction processing, analog-to-digital conversion processing, and decoding processing, a frame of touch-related data covering n*m capacitor nodes is obtained. The common-mode reduction processing ensures that the n analog voltage accumulation values ​​after coding multiple access accumulation processing are within the input range required by the analog-to-digital conversion processing. The coding accumulation matrix obtained from the coding multiple access accumulation processing forms a digital matrix to be decoded after the common-mode reduction processing and the analog-to-digital conversion processing. The touch-related data is obtained by decoding the digital matrix to be decoded. The reporting calculation module is used to acquire the touch-related data of two consecutive frames, and perform differential subtraction on the touch-related data of the two frames to form touch distribution information of n*m capacitive nodes. 2.The touch detection apparatus of claim 1, wherein, The frame processing module includes: The coding unit is used to generate code chips for each of the driving channels, and to generate m coding driving signals for each coding operation based on the code chips. The coding accumulation unit is used to acquire n*m ​​coupling signals formed at each capacitor node of m driving channels through each of the sensing channels, and to perform coding multiple access accumulation on the coupling signals of m capacitor nodes on each of the n sensing channels and the m coding driving signals for each coding to obtain the n analog voltage accumulation values. The common-mode reduction unit is used to process the n accumulated analog voltage values, subtract the common-mode analog voltage amount that exceeds the input range required by the analog-to-digital conversion process, and generate n analog voltage signals to be decoded. An analog-to-digital conversion unit is configured to convert n analog voltage signals to be decoded into n digital voltage signals to be decoded; and, The decoding unit is used to decode based on the n digital voltage signals to be decoded and the chips used by the m driving channels to generate the touch-related values ​​of the n*m ​​capacitive nodes in the one frame of touch-related data.

3. The touch detection device as described in claim 2, wherein the coding and accumulation unit performs coding k times to form n*k accumulated analog voltage values, and the decoding unit performs multiplication and addition on the corresponding n*k digital voltage signals to be decoded and k*m chips used by the driving channels to achieve decoding, generating touch-related values ​​of n*m capacitor nodes in the one frame of touch-related data, where k is a positive integer. 4.The touch detection apparatus of claim 2, wherein, The common-mode reduction unit includes at least one current source disposed at the output node of each of the n sensing channels, so as to make the accumulated value of the n analog voltages within the input range required by the analog-to-digital conversion process by means of current extraction or current addition. 5.The touch detection apparatus of claim 4, wherein, The common-mode reduction unit and the coding accumulation unit include: An integrator is used to integrate the charge of the output node of each of the n sensing channels to generate the n analog voltage signals to be decoded that do not exceed the input range required by the analog-to-digital conversion process, and input them to the analog-to-digital conversion unit. 6.The touch detection apparatus of claim 2, wherein, The coding accumulation unit performs k coding operations, and the common-mode analog voltage is determined by the common-mode value accumulated from the m coding drive signals during each coding operation, where k is a positive integer.

7. The touch detection device as described in claim 1, characterized in that, The two frames are respectively the touch-related data of the no-touch frame and the touch-related data of the touch-enabled frame.

8. A touch detection method, executed by a touch chip, for detecting capacitance changes in n*m capacitor nodes formed by m driving channels and n sensing channels, where m and n are positive integers, the touch detection method comprising: In each coding cycle, coding drive signals are loaded onto each of the driving channels, and n*m coupling signals formed at each of the capacitor nodes are acquired through each sensing channel. After coding multiple access accumulation processing, common-mode reduction processing, analog-to-digital conversion processing, and decoding processing, a frame of touch-related data covering n*m capacitor nodes is obtained. The common-mode reduction processing ensures that the accumulated n analog voltage values ​​after coding multiple access accumulation processing are within the input range required by the analog-to-digital conversion processing. The coding accumulation matrix obtained from coding multiple access accumulation processing forms a digital matrix to be decoded after the common-mode reduction processing and the analog-to-digital conversion processing. The touch-related data is obtained by directly decoding the digital matrix to be decoded. The touch-related data of two consecutive frames are acquired, and the touch-related data of the two frames are differentially subtracted to form the touch distribution information of n*m capacitive nodes.

9. An electronic device, characterized in that, Includes the touch detection device as described in any one of claims 1 to 7.

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