Electromagnetic touch sensing device, screen assembly, electronic equipment and touch system

Abstract

The embodiment of the utility model discloses an electromagnetic touch sensing device, a screen component, electronic equipment and a touch system, an electromagnetic touch screen is provided with a plurality of electrodes extending along a first direction, and at least two electrodes are coupled through an impedance module, so that a loop is formed between the two coupled electrodes. Then the voltage sampling module is used for collecting the voltage on the impedance module, a voltage signal reflecting the magnitude of the current in a loop of the two electrodes can be obtained, and the direction of the voltage on the impedance module between the two electrodes is determined due to the fact that the directions of the current in the sensing coil are the same; therefore, the position of the electromagnetic pen can be reflected by the position of the maximum voltage value, and a sampling mode in which the directions of currents on multiplexed electrodes between adjacent sensing coils are opposite due to direct current sampling and the position of the electromagnetic pen cannot be determined by the position of the maximum current signal is adopted. According to the embodiment of the invention, the position of the electromagnetic pen can be accurately judged through the voltage sampling signal of the voltage sampling module.

Description

Technical Field

[0001] The present application relates to the field of touch technologies, and in particular, to an electromagnetic touch sensing device, a screen assembly, an electronic device, and a touch system. Background Art

[0002] Currently, an electromagnetic touch screen applying EMR (Electro Magnetic Resonancey) technology has multiple mutually independent coils. These coils are divided into driving coils and sensing coils. The driving coils are connected to a touch chip to receive driving signals, and a changing magnetic field is induced on the surface of the electromagnetic touch screen through the coils. When an electromagnetic pen approaches the electromagnetic touch screen, a coil in the electromagnetic pen generates an induced current due to the magnetic field on the surface of the electromagnetic touch screen. The electromagnetic pen stores energy through methods such as capacitor energy storage, and then emits the energy in the form of a magnetic field through an internal oscillation circuit. In this way, the sensing coils of the electromagnetic touch screen can sense the magnetic field signal emitted by the electromagnetic pen, thereby inducing a current in the sensing coils. The electromagnetic touch screen then determines, through current sampling, that the position where the current is the largest in the current envelope signal is the position corresponding to the electromagnetic pen.

[0003] In addition to the above-mentioned solution of mutually independent coils, an electromagnetic touch screen can also short-circuit one end of the electrodes forming the coils together to form a comb-like structure as Figure 1 shown. In the solution of the comb-like structure, since there is a common end between two adjacent coils, when the electromagnetic pen is located above two adjacent coils, the current directions coupled at the common end of the adjacent coils are opposite, as Figure 2 the current directions shown, which makes the collected current positive, negative, or zero, and the current signal envelope is not monotonic, so that the electromagnetic touch screen cannot correspond the position where the current signal is the largest to the position of the electromagnetic pen. Utility Model Content

[0004] The following is an overview of the subject matter described in detail in this article. This overview is not intended to limit the protection scope of the claims.

[0005] Embodiments of the present application provide an electromagnetic touch sensing device, a screen assembly, an electronic device, and a touch system, which can obtain electromagnetic touch signals by converting to a voltage acquisition method, and can thus accurately determine the position of the electromagnetic pen.

[0006] On the one hand, embodiments of the present application provide an electromagnetic touch sensing device for electromagnetic touch signals, which is used to be coupled to an electromagnetic touch screen. The electromagnetic touch screen includes multiple electrodes extending along a first direction, and two adjacent electrodes form a sensing coil. The electromagnetic touch sensing device senses the change in the electromagnetic field of each sensing coil caused by an electromagnetic pen on the electromagnetic touch screen to sense the position of the electromagnetic pen. The electromagnetic touch sensing device includes:

[0007] An impedance module for coupling at least two of the electrodes;

[0008] A voltage sampling module for sampling the voltage on the impedance module.

[0009] In some embodiments, the impedance module is coupled between every two adjacent electrodes.

[0010] In some embodiments, the impedance module is coupled between two non-adjacent electrodes, and a predetermined number of electrodes are spaced between the two non-adjacent electrodes.

[0011] In some embodiments, the impedance module is coupled between two non-adjacent electrodes, and the number of electrodes spaced between the two non-adjacent electrodes is not fixed.

[0012] In some embodiments, the electromagnetic touch screen further includes a plurality of drive coils arranged along a second direction perpendicular to the first direction. Wherein, each of the drive coils is driven so that the electromagnetic field change of the overlapping portion of each sensing coil and the currently driven drive coil is sensed by the electromagnetic touch sensing device to sense the position of the electromagnetic pen.

[0013] In some embodiments, the electromagnetic touch sensing device further includes a switching device connected in series with the impedance module. Wherein, when the switching device is turned off, the sensing coil serves as the drive coil.

[0014] In some embodiments, the electromagnetic touch sensing device further includes a control module coupled to the output end of the voltage sampling module, and configured to determine the position of the electromagnetic pen according to the voltage sampling signal output by the voltage sampling module.

[0015] In some embodiments, the impedance module includes a resistor network including at least one resistor, and the resistor network is used to couple two of the electrodes.

[0016] In some embodiments, the impedance module further includes a capacitor connected in series or in parallel with any one of the resistors.

[0017] In some embodiments, the structure of the impedance module is one of the following:

[0018] The resistor network includes a first resistor, and the impedance module further includes a first capacitor connected in parallel with the first resistor;

[0019] The resistor network includes a second resistor and a third resistor connected in series, and the impedance module further includes a second capacitor connected in parallel with the second resistor;

[0020] The resistor network includes a fourth resistor and a fifth resistor connected in parallel, and the impedance module further includes a third capacitor connected in series with the fourth resistor.

[0021] In some embodiments, the voltage sampling module includes a first amplifier, a second amplifier, and a third amplifier, wherein,

[0022] The first amplifier amplifies the voltage of one of the two electrodes to generate a first amplified signal;

[0023] The second amplifier amplifies the voltage of the other of the two electrodes to generate a second amplified signal;

[0024] The third amplifier amplifies the differential signal between the first amplified signal and the second amplified signal to obtain a voltage sampling signal.

[0025] In some embodiments, the first amplifier, the second amplifier, and the third amplifier are all fully differential operational amplifiers, wherein,

[0026] The first amplifier has a first differential input terminal, a second differential input terminal, and a first output terminal. The first differential input terminal is coupled to one of the two electrodes, and the second differential input terminal is connected to a reference voltage; the second amplifier has a third differential input terminal, a fourth differential input terminal, and a second output terminal. The third differential input terminal is coupled to the other of the two electrodes, and the fourth differential input terminal is connected to a reference voltage; the third amplifier has a fifth differential input terminal, a sixth differential input terminal, and a third output terminal. The fifth differential input terminal is used to receive the first amplified signal output from the first output terminal, the sixth differential input terminal is used to receive the second amplified signal output from the second output terminal, and the third output terminal is used to output the voltage sampling signal.

[0027] In some embodiments, the first amplifier, the second amplifier, and the third amplifier are all single-ended operational amplifiers, wherein,

[0028] The first amplifier has a first non-inverting input terminal, a first inverting input terminal, and a first output terminal. The first non-inverting input terminal is coupled to one of the two electrodes, and the first inverting input terminal is connected to a reference voltage. The second amplifier has a second non-inverting input terminal, a second inverting input terminal, and a second output terminal. The second non-inverting input terminal is coupled to the other of the two electrodes, and the second inverting input terminal is connected to a reference voltage. The third amplifier has a third non-inverting input terminal, a third inverting input terminal, and a third output terminal. The third non-inverting input terminal is configured to receive the first amplified signal output from the first output terminal, the third inverting input terminal is configured to receive the second amplified signal output from the second output terminal, and the third output terminal is configured to output the voltage sampling signal.

[0029] In some embodiments, the first amplifier, the second amplifier, and the third amplifier are all single-ended operational amplifiers, where

[0030] The first amplifier has a first non-inverting input terminal, a first inverting input terminal, and a first output terminal. The second amplifier has a second non-inverting input terminal, a second inverting input terminal, and a second output terminal. The first non-inverting input terminal is coupled to one of the two electrodes, the second non-inverting input terminal is coupled to the other of the two electrodes, and the first inverting input terminal is coupled to the second inverting input terminal. The third amplifier has a third non-inverting input terminal, a third inverting input terminal, and a third output terminal. The third non-inverting input terminal is configured to receive the second amplified signal output from the second output terminal, the third inverting input terminal is configured to receive the first amplified signal output from the first output terminal, and the third output terminal is configured to output the voltage sampling signal.

[0031] On the other hand, an embodiment of the present application further provides a screen assembly, including the aforementioned electromagnetic touch sensing device, and the electromagnetic touch sensing device is coupled to the electromagnetic touch screen.

[0032] In some embodiments, it further includes a capacitive touch screen, and the capacitive touch screen is coupled to the electromagnetic touch screen to which the electromagnetic touch sensing device is coupled.

[0033] On the other hand, an embodiment of the present application further provides an electronic device, including the aforementioned screen assembly.

[0034] On the other hand, an embodiment of the present application further provides a touch control system, including the aforementioned electronic device and an electromagnetic pen.

[0035] The embodiments of the present application at least include the following beneficial effects: The electromagnetic touch screen has multiple electrodes extending along a first direction, and adjacent two electrodes form sensing coils arranged in the first direction. In the embodiments of the present application, at least two electrodes are coupled through an impedance module, so that a loop is formed between the two coupled electrodes. Then, a voltage sampling module is used to collect the voltage on the impedance module, and a voltage signal reflecting the magnitude of the current in the loop of the two electrodes can be obtained. Since the current directions in the sensing coils are the same, the direction of the voltage on the impedance module between the two electrodes is determined. Therefore, the position of the electromagnetic pen can be reflected by the position of the maximum voltage. Compared with the sampling method in which the current directions on the electrodes multiplexed between adjacent sensing coils are opposite due to direct current sampling and the position of the electromagnetic pen cannot be determined by the position of the maximum current signal, the embodiments of the present application can accurately determine the position of the electromagnetic pen through the voltage sampling signal of the voltage sampling module.

[0036] Other features and advantages of the present application will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present application. The objectives and other advantages of the present application can be achieved and obtained through the structures specifically pointed out in the specification, the claims, and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings are used to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solutions of the present application and do not constitute a limitation to the technical solutions of the present application.

[0038] Figure 1 It is a schematic diagram of the arrangement of the drive coil and the sensing coil provided by the embodiment of the present application;

[0039] Figure 2 It is a schematic diagram that the currents flowing through the electrodes shared by two adjacent sensing coils are opposite provided by the embodiment of the present application;

[0040] Figure 3 It is a schematic diagram of connecting the electromagnetic touch screen and the electromagnetic touch sensing device through a flexible cable provided by the embodiment of the present application;

[0041] Figure 4 It is a schematic diagram of the electromagnetic touch sensing device connected to the electromagnetic touch screen provided by the embodiment of the present application;

[0042] Figure 5 It is a schematic diagram of terminating a resistor R between two adjacent electrodes provided by the embodiment of the present application;

[0043] Figure 6 It is a schematic diagram of terminating a resistor R between two electrodes separated by a fixed number of sensing coils provided by the embodiment of the present application;

[0044] Figure 7 Schematic diagram of the termination resistor R between two electrodes with a randomly varying number of sensing coils provided by an embodiment of the present application;

[0045] Figure 8 Schematic diagram of a structure of an impedance module provided by an embodiment of the present application;

[0046] Figure 9 Another schematic diagram of a structure of an impedance module provided by an embodiment of the present application;

[0047] Figure 10 Another schematic diagram of a structure of an impedance module provided by an embodiment of the present application;

[0048] Figure 11 Schematic diagram of a structure with a switch module connected in series with an impedance module provided by an embodiment of the present application;

[0049] Figure 12 Circuit diagram of a voltage sampling module using a fully differential operational amplifier provided by an embodiment of the present application;

[0050] Figure 13 Circuit diagram of a voltage sampling module using a single-ended operational amplifier provided by an embodiment of the present application;

[0051] Figure 14 Circuit diagram of a voltage sampling module using an instrumentation operational amplifier provided by an embodiment of the present application. Detailed implementation manners

[0052] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0053] The electromagnetic screen is a touch screen that applies EMR technology. The electromagnetic screen is used in conjunction with an electromagnetic pen. Touch actions such as clicking and drawing lines can be achieved on the electromagnetic screen through the electromagnetic pen, thereby realizing high-precision operations such as painting, text editing, and annotation. Among them, multiple electrodes (or called electrodes) are arranged in the electromagnetic screen. One end of two electrodes is connected to each other, and the other end is connected to the touch chip of the electromagnetic screen to form a coil, and the coils are independently arranged with respect to each other. These coils are divided into driving coils and sensing coils. The driving coils are all connected to the touch chip to receive the driving signal of the touch chip, and the sensing coils are all connected to the touch chip to receive the magnetic field signal emitted by the electromagnetic pen. The directions of these driving coils are the same, and the directions of these sensing coils, and the directions of the driving coils and the sensing coils are perpendicular to each other. In this way, multiple mutually independent coils arranged vertically and horizontally are arranged in the electromagnetic screen, forming multiple grids corresponding to different regions on the surface of the electromagnetic screen. The electromagnetic pen includes a coil inductor and an oscillating emission circuit with a capacitor. When working, the electromagnetic screen sends a driving signal to the driving coil, and the driving coil induces a magnetic field on the surface of the electromagnetic screen. The coil inductor of the electromagnetic pen cuts the magnetic induction lines on the surface of the electromagnetic field, induces a current in the coil inductor and charges the capacitor. After the capacitor is charged, it emits a magnetic field through the oscillating circuit at a certain resonance frequency. The sensing coil of the electromagnetic touch screen receives the magnetic field emitted by the electromagnetic pen and induces a current in the sensing coil. The touch chip determines the position of the electromagnetic pen by collecting the induced current. Generally speaking, the area covered by the magnetic field emitted by the electromagnetic pen has multiple sensing coils, and the sensing coils in the covered area will all induce currents. Among them, the sensing coil with the largest induced current is the closest to the position of the electromagnetic pen. Therefore, the touch chip obtains multiple induced currents to obtain a current signal envelope, and determines the sensing coil corresponding to the point with the maximum value of the current signal envelope as the sensing coil closest to the electromagnetic pen, and then can determine the position of the electromagnetic pen.

[0054] The above-mentioned electromagnetic touch screen detects electromagnetic signals based on the structure of mutually independent coils, and then realizes the determination of the position of the electromagnetic pen. Since each coil has two electrodes, these electrodes need to be connected to the touch chip outside the electromagnetic touch screen. Therefore, at the edge of the electromagnetic touch screen, the number of electrodes appears relatively large, resulting in a relatively large number of wires on the wiring connecting the electromagnetic touch screen to the touch chip, occupying the wiring area at the edge of the electromagnetic touch screen, and thus causing a relatively large screen border of the electromagnetic touch screen product. In order to reduce the screen border and enable the electromagnetic touch screen to be applied to narrow-border products such as mobile phones and tablets, the electrodes close to each other between adjacent coils are reused, that is, adjacent two coils have three electrodes. A coil is formed by the first electrode and the second electrode, and another coil is formed by the second electrode and the third electrode. In this way, it forms as Figure 1The coils of the comb structure shown. This design can ensure that, with the same number and area of coils, the number of outgoing lines is reduced by half, which can reduce the area of the wire arrangement and is applicable to products with narrow bezel screens. At the same time, a time-division driving method can be adopted later to flexibly drive a coil formed by combining any two electrodes, and then, based on the signals of the driving coil and the sensing coil, the touch coordinates of the electromagnetic touch screen can be calculated.

[0055] For the sensing coils of the comb structure, when receiving the magnetic field signal emitted by the electromagnetic pen, currents in the same direction are formed in multiple sensing coils. However, in the electrode serving as the common terminal, the current directions of adjacent sensing coils on this electrode are opposite, resulting in the current on this electrode possibly being positive, negative, or zero. This causes there to be points of current mutation in the current signal envelope obtained by the touch chip, that is, the current signal envelope is not monotonic, and the position of the electromagnetic pen cannot be directly determined by the maximum value of the current signal envelope. Specifically, refer to Figure 2 The schematic diagram of only a small number of sensing coils shown. The electrode Rx1 and the electrode Rx2 form a sensing coil (hereinafter referred to as the Rx1&Rx2 coil), and the electrode Rx2 and the electrode Rx3 form another sensing coil (hereinafter referred to as the Rx2&Rx3 coil). These two sensing coils share the electrode Rx2 as the common terminal. When the electromagnetic pen is above the Rx1&Rx2 coil and the Rx2&Rx3 coil, the directions of the induced currents in the two sensing coils are both clockwise. The current I2A on the electrode Rx2 is actually the result of the current coupling of adjacent two sensing coils. Obviously, the current directions of the two sensing coils on the electrode Rx2 are opposite. When the electromagnetic pen approaches the Rx1&Rx2 coil, the direction of the current I2A on the electrode Rx2 is positive. When the electromagnetic pen approaches the Rx2&Rx3 coil, the direction of the current I2A on the electrode Rx2 is negative. When the electromagnetic pen is exactly in the middle of these two sensing coils, the current I2A on the electrode Rx2 is zero. Therefore, the above-mentioned comb structure causes the sampled current signals on the electrode to be positive, negative, or zero when the electromagnetic pen is in different positions, making the current signal envelope not monotonic and unable to accurately determine the position of the electromagnetic pen.

[0056] Based on this, embodiments of the present application provide an electromagnetic touch sensing device, a screen assembly, an electronic device, and a touch system. The electromagnetic touch screen coupled to the electromagnetic touch sensing device has multiple electrodes extending along a first direction, and adjacent two electrodes form a sensing coil arranged in the first direction. In the embodiments of the present application, at least two electrodes are coupled through an impedance module, so that a loop is formed between the two coupled electrodes. Then, a voltage sampling module is used to collect the voltage on the impedance module, and a voltage signal reflecting the magnitude of the current in the loop of the two electrodes can be obtained. Since the current directions in the sensing coils are the same, the direction of the voltage on the impedance module between the two electrodes is determined. Therefore, the position of the electromagnetic pen can be reflected by the position of the maximum voltage. Compared with the sampling method in which direct current sampling causes the current directions on the electrodes multiplexed between adjacent sensing coils to be opposite and the position of the electromagnetic pen cannot be determined by the position of the maximum current signal, the embodiments of the present application can accurately determine the position of the electromagnetic pen through the voltage sampling signal of the voltage sampling module.

[0057] The electromagnetic touch sensing device will be described below with reference to the accompanying drawings.

[0058] Refer to Figure 3 and Figure 4 as shown, Figure 3 and Figure 4 are an electromagnetic touch sensing device provided by an embodiment of the present application, which is used to be coupled to an electromagnetic touch screen. The electromagnetic touch screen includes multiple electrodes extending along a first direction, and adjacent two electrodes form a sensing coil. The position of the electromagnetic pen is sensed by sensing the electromagnetic field changes of each sensing coil caused by the electromagnetic pen on the electromagnetic touch screen through the electromagnetic touch sensing device.

[0059] In this embodiment, the electromagnetic touch sensing device is coupled to the electromagnetic touch screen for signal interaction. The coupling method can be through a cable connection or through the docking of their respective interfaces; for example Figure 3 in which the electromagnetic touch sensing device is connected to the electromagnetic touch screen through a cable, and the electrodes in the electromagnetic touch screen are connected to the circuit in the electromagnetic touch sensing device. The electromagnetic touch screen provides a first cable interface at the edge of the screen, and the electromagnetic touch sensing device provides a second cable interface. Then, the first cable interface and the second cable interface are connected through a cable to connect the electromagnetic touch screen and the electromagnetic touch sensing device, or Figure 4 in which the electromagnetic touch sensing device is integrated with a cable and directly connected to the first cable interface of the electromagnetic touch screen. With the above-mentioned wire outlet method of the comb structure, the number of wires on the cable is reduced, thereby reducing the occupancy of the edge area of the electromagnetic screen by the cable, enabling the electromagnetic touch screen and the electromagnetic touch sensing device to be applied to products with narrow borders.

[0060] Among them, the electromagnetic touch screen of this embodiment has sensing coils in a first direction and driving coils in a second direction. The driving coils are parallel to each other, the sensing coils are parallel to each other, and the driving coils and the sensing coils are perpendicular to each other, forming a grid covering the display area of the electromagnetic touch screen. Taking Figure 1 as an example, the electrodes of the sensing coils in the first direction ( Figure 1 the horizontal direction) are Rx0, Rx1, Rx2, Rx3,...,Rxn, and the electrodes of the driving coils in the second direction ( Figure 1 the vertical direction) are Tx0, Tx1, Tx2, Tx3,...,Txn; each Rx electrode is short-circuited on the left side in Figure 1 (equivalent to being short-circuited to a common terminal), and each Rx electrode is connected to the electromagnetic touch sensing device on the right side in Figure 1 ; each Tx electrode is short-circuited on the upper side in Figure 1 (equivalent to being short-circuited to another common terminal), and each Tx electrode is connected to the electromagnetic touch sensing device on the lower side in Figure 1 . It should be noted that although the electrodes of the driving coils and the electrodes of the sensing coils described above are both n + 1, according to the actual situation, the number of electrodes of the driving coils and the number of electrodes of the sensing coils may not be the same to face electromagnetic touch screens with different length and width dimensions.

[0061] According to the currently commonly used receiving technology, the current signal on the electrode Rx is directly collected, and the position of the electromagnetic pen is determined by the maximum value of the current in the current signal envelope. This method is feasible in the scheme where the coils are independent of each other because the currents induced in each coil are independent of each other and will not affect adjacent coils. However, in the above comb structure, as known before, one electrode is shared between adjacent sensing coils. Since the directions of the currents simultaneously induced in adjacent two sensing coils are the same, the directions of the currents on the electrode as the common terminal are opposite, and the position of the electromagnetic pen cannot be reflected based on the maximum value of the current signal envelope. Therefore, in the embodiment of the present application, the resistance termination method is adopted to couple two electrodes in the comb structure, so that a current path through the resistance is formed between the two electrodes, and then the voltage across the resistance is sampled. In this way, the direction of the current flowing through the resistance is determined, and the direction of the sampled voltage value is also determined. Therefore, the voltage signal envelope obtained by the electromagnetic touch sensing device is monotonic, and the position of the electromagnetic pen can be reflected based on the maximum value by analyzing the voltage signal envelope, avoiding the problem that the position of the electromagnetic pen cannot be accurately judged due to the influence of the electrode as the common terminal in the current sampling scheme.

[0062] Specifically, in the embodiment of the present application, the electromagnetic touch sensing device includes:

[0063] An impedance module for coupling at least two electrodes;

[0064] A voltage sampling module for sampling the voltage on the impedance module.

[0065] The electromagnetic touch sensing device is connected to the electrodes of the electromagnetic touch screen. An impedance module is arranged in the electromagnetic touch sensing device, and the impedance module is connected between two electrodes selected from the electrodes of the at least one sensing coil, so that a loop is formed by the two selected electrodes through the impedance module. All the electrodes of the comb-shaped sensing coil are short-circuited together. Therefore, one end of the two electrodes coupled to the impedance module is short-circuited, and the other end is connected to both ends of the impedance module. Thus, the loop formed by these two electrodes can also induce a current under the magnetic field emitted by the electromagnetic pen. In this way, a sampling network as shown in Figure 5 can be formed. Each loop with an impedance module can be used to induce a current under the action of the magnetic field emitted by the electromagnetic pen. The direction of the current in the loop is related to the direction of the magnetic field emitted by the electromagnetic pen. When the direction of the magnetic field emitted by the electromagnetic pen is determined, the direction of the current in the loop is also determined, and the current flowing through the impedance module is also determined, that is, there will be no positive and negative voltages at the same time. Therefore, multiple sampling voltage values in the same direction can be collected by the voltage sampling module, and a monotonic voltage signal envelope can be obtained. Furthermore, the position of the electromagnetic pen can be reflected according to the maximum value of the voltage signal envelope.

[0066] It should be noted that in order to cover the effective touch area of the entire electromagnetic touch screen, at least in the effective touch area, the electrodes of each sensing coil are coupled with the above-mentioned impedance module, so that each electrode forms a loop with another electrode. No matter where the electromagnetic pen is located in the effective touch area, there is a corresponding loop in the effective touch area to sense the magnetic field emitted by the electromagnetic pen. In addition to the effective touch area, for the non-effective touch area of the electromagnetic touch screen, the impedance module can also be coupled to two electrodes in the above-mentioned manner to form a loop, that is, the electrodes of each sensing coil of the entire electromagnetic touch screen are coupled with the impedance module.

[0067] The voltage sampling module is coupled to the impedance module to collect the voltage across the impedance module as the voltage sampling signal. This voltage sampling signal is proportional to the current in the loop where the impedance module is located. In order to sample the impedance module of each loop, the number of voltage sampling modules corresponds one-to-one with the number of impedance modules, and both ends of the voltage sampling module are coupled to both ends of the impedance module, or coupled to the two electrodes forming the loop. In this way, all impedance modules can be covered, and the signal at any position within the effective touch area of the electromagnetic touch screen by the electromagnetic pen can be collected.

[0068] The electromagnetic touch sensing device is equivalent to the touch chip of the electromagnetic touch screen and has functions such as sending driving signals, collecting sensing signals, and analyzing sensing signals of the touch chip. In the embodiment of the present application, the electromagnetic touch sensing device further provides an impedance module and a voltage sampling module corresponding to the impedance module compared with the conventional touch chip. When the electromagnetic touch sensing device is connected to the cable interface of the electromagnetic screen, the impedance module of the electromagnetic touch sensing device is coupled to the electrode of the electromagnetic screen to form a loop. Then, when the electromagnetic screen is working, the voltage of the impedance module in the loop is collected through the voltage acquisition module to obtain a voltage sampling signal, and the position of the electromagnetic pen above the electromagnetic screen is judged through voltage signal envelope analysis.

[0069] As described above, the electromagnetic touch screen further includes a plurality of drive coils arranged along the second direction, and the second direction is perpendicular to the first direction. Among them, each drive coil is driven so that the electromagnetic field change of the overlapping part of each sensing coil and the currently driven drive coil is sensed through the electromagnetic touch sensing device to sense the position of the electromagnetic pen.

[0070] During the operation of the electromagnetic touch screen, a current is passed through the drive coil by the drive signal, and the drive coil forms a magnetic field on the surface of the electromagnetic touch screen. The coil inductance in the electromagnetic pen charges the internal capacitor by cutting the magnetic induction line, and then a magnetic field with a certain resonance frequency is emitted from the electromagnetic pen to the electromagnetic touch screen through the oscillation circuit. Since the sensing coils are arranged in the first direction, only by judging the induced current of the sensing coils under the magnetic field emitted by the electromagnetic pen, the position of the electromagnetic pen in only one direction can be determined. Therefore, the electromagnetic touch sensing device, or the touch chip, needs to send a drive signal to the drive coil through a specific drive method, and then cooperate with the signal collected by the sensing coil to determine the position of the electromagnetic pen in the first direction and the second direction. For example, for Figure 1The drive coils of the comb-like structure shown can be sequentially supplied with drive signals from left to right in a time-division manner. When a drive signal is applied to a certain drive coil and a signal can be induced in the sense coil, it indicates that the electromagnetic pen is above the drive coil in the second direction. Then, by analyzing the signal envelope of the sense coil, it is determined above which sense coil the electromagnetic pen is in the first direction. In this way, the position of the electromagnetic pen is determined by using the drive coil and the sense coil in mutually perpendicular directions, thereby determining the position of the electromagnetic pen on the two-dimensional plane of the electromagnetic touch screen. It can be understood that in addition to the above-mentioned method of sending drive signals to the drive coils from left to right in a time-division manner, other methods can also be used to drive the drive coils. For example, multiple adjacent drive coils can be simultaneously supplied with drive signals each time. After determining that the electromagnetic pen is in the area where these adjacent drive coils are located, the drive signals are then sequentially supplied to these adjacent drive coils in a time-division manner in sequence, and it is also possible to determine above which drive coil the electromagnetic pen is located. This application does not limit the drive method. For different drive methods, during the process of the electromagnetic touch sensing device receiving the sense signal, the analysis process of the signal envelope is different. However, based on the above-mentioned method of using the impedance module for voltage sampling, when the electromagnetic touch sensing device analyzes the signal envelope, it determines the position of the electromagnetic pen according to the point of the maximum voltage in the signal envelope.

[0071] Referring to Figure 5 the embodiment shown, an impedance module ( Figure 5 denoted as resistor R in the figure) is coupled between every two adjacent electrodes. That is to say, both ends of the impedance module are respectively connected to two adjacent electrodes, so that impedance modules are coupled to the two electrodes of each sense coil in the electromagnetic touch sensing device.

[0072] In addition to Figure 5 the structure shown, the two electrodes can also be selected from two non-adjacent electrodes. In some embodiments, there are a fixed number of electrodes or different numbers of electrodes between two non-adjacent electrodes. Among them, the fixed number means that the number of electrode strips separated between the two electrodes coupled by each impedance module is a fixed value, and the different numbers mean that the number of electrode strips separated between the two electrodes coupled by each impedance module is not all the same.

[0073] For example, referring to Figure 6As shown, the electrodes of the sensing coil are arranged from top to bottom. Starting from the topmost electrode Rx0, they are successively Rx1, Rx2, Rx3, …, Rx2k + 1, etc. The two ends of impedance module R0 are respectively connected to electrode Rx0 and electrode Rxk. The two ends of impedance module R1 are respectively connected to electrode Rx1 and electrode Rxk + 1. The two ends of impedance module R2 are respectively connected to electrode Rx2 and electrode Rxk + 2. The two ends of impedance module Rk are respectively connected to electrode Rxk and electrode Rx2k. The two ends of impedance module Rk + 1 are respectively connected to electrode Rxk + 1 and electrode Rx2k + 1. The two ends of impedance module Rk + 2 are respectively connected to electrode Rxk + 2 and electrode Rx2k + 2, and so on. The number of electrodes between the two electrodes coupled by the impedance module is k (k is an integer greater than or equal to 2), thus forming multiple loops. Correspondingly, using V0, V1, …, Vk + 1, Vk + 2 to represent the corresponding relationships between different voltage sampling modules and the loops, for the loop where impedance module R0 is located, it is connected to voltage sampling module V0. For the loop where impedance module R1 is located, it is connected to voltage sampling module V1. For the loop where impedance module R2 is located, it is connected to voltage sampling module V2. For the loop where impedance module Rk is located, it is connected to voltage sampling module VK. For the loop where impedance module Rk + 1 is located, it is connected to voltage sampling module VK + 1. For the loop where impedance module Rk + 2 is located, it is connected to voltage sampling module VK + 2, and so on.

[0074] For example, referring to Figure 7 As shown, the electrodes of the sensing coil are arranged from top to bottom. Starting from the topmost electrode Rx0, they are successively Rx1, Rx2, Rx3, …, Rxn, etc. The two ends of impedance module R0 are respectively connected to electrode Rx0 and electrode Rx i. The two ends of impedance module R1 are respectively connected to electrode Rx1 and electrode Rxj. The two ends of impedance module R2 are respectively connected to electrode Rx2 and electrode Rxk. The two ends of impedance module Ri are respectively connected to electrode Rxi and electrode Rx l. The two ends of impedance module Rj are respectively connected to electrode Rxj and electrode Rxm. The two ends of impedance module Rk are respectively connected to electrode Rxk and electrode Rxn. The number of electrodes between the two electrodes coupled by the impedance module is not a fixed value (i, j, k, l, m, n are all integers greater than 2, and i, j, k, l, m, n increase in sequence), thus forming multiple loops. Correspondingly, using V0, V1,......, Vj, Vk to represent the corresponding relationships between different voltage sampling modules and the loops, for the loop where impedance module R0 is located, it is connected to voltage sampling module V0. For the loop where impedance module R1 is located, it is connected to voltage sampling module V1. For the loop where impedance module R2 is located, it is connected to voltage sampling module V2. For the loop where impedance module Ri is located, it is connected to voltage sampling module Vi. For the loop where impedance module Rj is located, it is connected to voltage sampling module Vj. For the loop where impedance module Rk is located, it is connected to voltage sampling module Vk, and so on.

[0075] The above-mentioned Figure 6 and Figure 7 both have structures that are Figure 5 transformations of the structure. By forming a loop across multiple electrodes, the induction range corresponding to the loop on the electromagnetic touch screen is larger, and it can sense the magnetic fields emitted by electromagnetic pens in a larger range, facilitating the electromagnetic touch sensing device to obtain voltage sampling signals in a larger range and improving the accuracy of judging the position of the electromagnetic pen. It can be understood that Figure 5 、 Figure 6 and Figure 7 structures can be mixed and used in the same electromagnetic touch screen. The electromagnetic touch screen is divided into multiple regions, and the coils in different regions can adopt Figure 5 、 Figure 6 and Figure 7 any one of the structures, or the coils within the same region can adopt Figure 5 、 Figure 6 and Figure 7 any two or more of the structures. This application places no restrictions on this.

[0076] It can be understood that the electromagnetic touch sensing device includes multiple impedance modules, and the resistance values of these impedance modules can be the same or different. For example, for Figure 5In the structure shown, each resistor R is regarded as an impedance module. The resistor R is connected between two adjacent electrodes. If the resistance values of each resistor R are equal, the magnitude relationship between the voltage signals of each loop received by the electromagnetic touch sensing device directly reflects the magnitude relationship of the induced current on the loop corresponding to the voltage signal. In this way, the electromagnetic touch sensing device directly determines the position of the electromagnetic pen by judging the maximum value in the voltage signal envelope. Among them, when the electromagnetic pen is above the electrode Rx2, the induced current magnitudes in the coils of Rx1&Rx2 and Rx2&Rx3 are equal. Since the resistance R of the coil of Rx1&Rx2 and the resistance R of the coil of Rx2&Rx3 are equal, the current on the electrode Rx2 is zero. At this time, the voltage magnitudes across the resistors R of these two coils are equal. Although there are two maximum values in the voltage signal of the voltage sampling module, the voltage signal envelope of the electromagnetic touch sensing device can still determine the position of the electromagnetic pen based on the maximum value. At this time, the determined position of the electromagnetic pen can be located in the coil of Rx1&Rx2 or in the coil of Rx2&Rx3 (for example, this judgment result is presented through the handwriting), which is determined according to the judgment strategy of the electromagnetic touch sensing device, but obviously there will be no serious deviation in the position judgment of the electromagnetic pen. If the resistance values of the resistor R are not equal, the electromagnetic touch sensing device needs to process the voltage sampling signal output by the voltage sampling module according to the magnitude of the resistance R corresponding to the loop. For example, multiply the voltage sampling signal by a coefficient that is negatively correlated with the magnitude of the resistance value of the impedance module. Through this system, the voltage sampling signal can be adjusted to a unified measurement standard, which is convenient for the electromagnetic touch sensing device to judge the maximum value in the voltage signal envelope to determine the position of the electromagnetic pen.

[0077] In addition, the electromagnetic touch sensing device further includes a control module. The control module is coupled to the output end of the voltage sampling module and is configured to determine the position of the electromagnetic pen according to the voltage sampling signal output by the voltage sampling module. In some possible embodiments, the control module is the main logic control hardware of the electromagnetic touch sensing device. It is coupled to the driving coil and the sensing coil in the circuit, sends driving signals to the driving coil in a certain manner, and receives the signals of the sensing coil (depending on the driving method, it may also be to receive the signals of both the sensing coil and the driving coil), and then determines the position where the electromagnetic pen is located according to the received signals. In this embodiment, the control module is also coupled to the voltage sampling module and receives the voltage sampling signal output by the voltage sampling module. Since the electromagnetic touch sensing device is connected to the electromagnetic touch screen, the impedance module is used to couple the two electrodes of the electromagnetic touch screen to form a loop. At this time, the control module uses the voltage sampling signal to replace the traditional current sampling signal to determine the position of the electromagnetic pen. In some other possible embodiments, the control module is only one of the logic control hardwares in the electromagnetic touch sensing device. It is coupled to the sensing coil and another logic control hardware in the circuit. The other logic control hardware is used to send driving signals and synchronize the driving signals or driving methods to the control module. In this way, the control module can determine the position of the electromagnetic pen according to the received driving signals or driving methods and the voltage sampling signals received from the voltage sampling module. In some other possible embodiments, the control module is only one of the logic control hardwares in the electromagnetic touch sensing device. It is coupled to the sensing coil in the circuit. The control module gives a preliminary judgment result of the position of the electromagnetic pen according to the voltage sampling signal received from the voltage sampling module, and sends this preliminary judgment result to another logic control hardware, and the other logic control hardware further determines the position where the electromagnetic pen is located. In short, the control module is connected to the voltage sampling module to receive the voltage sampling signal, and then preliminarily determines or finally determines the position where the electromagnetic pen is located according to the voltage signal envelope corresponding to the voltage sampling signal.

[0078] The impedance module can actually include multiple resistive elements such as resistors. Figure 5 Although the impedance module is shown as resistor R in the structure shown, Figure 5 it is a circuit topology diagram. Therefore, resistor R may actually be a resistor network composed of multiple actual resistors, that is, the impedance module includes a resistor network. The resistor network includes at least one resistor, and the resistor network is used to couple the two electrodes. By different resistor combinations, resistor networks with different resistance values can be obtained, which can match electromagnetic touch screens and electromagnetic touch sensing devices with different requirements. In addition, a capacitor can be added to the resistor network. The capacitor can be connected in series or in parallel with one or more resistors in the resistor network, and can filter the electrical signals in the loop to a certain extent, improving the accuracy of sampling by the subsequent voltage sampling module.

[0079] In the actual use process, the impedance module can be composed of several resistors and capacitors. For example, the structure of the impedance module adopts one of the following:

[0080] The resistor network includes a first resistor, and the impedance module further includes a first capacitor connected in parallel with the first resistor;

[0081] The resistor network includes a second resistor and a third resistor connected in series, and the impedance module further includes a second capacitor connected in parallel with the second resistor;

[0082] The resistor network includes a fourth resistor and a fifth resistor connected in parallel, and the impedance module further includes a third capacitor connected in series with the fourth resistor.

[0083] The above three structures are illustrated by Figure 8 , Figure 9 and Figure 10 for example.

[0084] Referring to Figure 8 the impedance module shown includes a first resistor (represented by resistor R in Figure 8 ) and a first capacitor (represented by capacitor C in Figure 8 ). Taking the impedance module between electrode Rx0 and electrode Rx1 as an example, resistor R forms a resistor network with a single resistor, and both ends of the resistor network are respectively connected to electrode Rx0 and electrode Rx1, and capacitor C is connected in parallel with resistor R. Figure 8 Each of the other sensing coils in

[0085] is connected with resistor R and capacitor C in the above manner. Among them, capacitor C can adopt a device with a relatively small capacitance value to filter high-frequency noise in the loop composed of two electrodes and the impedance module. Figure 9 Referring to Figure 9 the impedance module shown includes a second resistor (represented by resistor R1 in Figure 9 ), a third resistor (represented by resistor R2 in Figure 9 ) and a second capacitor (represented by capacitor C1 in Figure 9 ). Taking the impedance module between electrode Rx0 and electrode Rx1 as an example, resistor R1 and resistor R2 are connected in series to form a resistor network, and both ends of the resistor network are respectively connected to electrode Rx0 and electrode Rx1, and capacitor C1 is connected in parallel with resistor R1.

[0086] Referring to Figure 10The impedance module shown includes a fourth resistor (denoted as resistor R1 in Figure 10 ), a fifth resistor (denoted as resistor R2 in Figure 10 ), and a third capacitor (denoted as capacitor C1 in Figure 10 ). Taking the impedance module between electrode Rx0 and electrode Rx1 as an example, resistor R1 and resistor R2 are connected in parallel to form a resistor network. The two ends of the resistor network are respectively connected to electrode Rx0 and electrode Rx1, and capacitor C1 is connected in series with resistor R1. Figure 10 Each of the other sensing coils in

[0087] is connected to resistor R1, resistor R2, and capacitor C1 in the above manner. Capacitor C1 can use a device with a relatively small capacitance value to filter out high-frequency noise in the loop formed by the two electrodes and the impedance module. Figure 11As shown, the impedance modules of the switching devices are set in series. Among them, when the switching device is closed, the corresponding coil serves as a sensing coil, and when the switching device is open, the corresponding coil serves as a driving coil. In this way, the electromagnetic touch sensing device or the touch chip can implement the above-mentioned multiplexing scheme of the driving coil and the sensing coil by switching the on / off state of the switching device. Among them, the switching device can adopt a highly integrated electronic switch such as an MOS transistor or a triode, and the control end of the switching device is connected to the electromagnetic touch sensing device or the touch chip, and the electromagnetic touch sensing device or the touch chip controls whether the switching device is turned on or off according to which coil the current driving signal is sent to.

[0088] There are various implementation methods for the circuit of the voltage sampling module. For a highly integrated electromagnetic touch sensing device or touch chip, since the number of sensing coils is large, it is not suitable to use devices with large volumes, such as inductors and other components with large volumes, for the circuit elements of the voltage sampling module. It is possible to consider using a highly integrated operational amplifier, etc. for differential comparison and output. In some embodiments, in order to ensure the current in the loop formed by the two electrodes and the impedance module and ensure high sampling accuracy, it is necessary to set a device with a high-impedance input for sampling. For example, the voltage sampling module includes a first amplifier G1, a second amplifier G2, and a third amplifier G3, where,

[0089] The first amplifier G1 amplifies the voltage of one of the two electrodes to generate a first amplified signal;

[0090] The second amplifier G2 amplifies the voltage of the other of the two electrodes to generate a second amplified signal;

[0091] The third amplifier G3 amplifies the differential signal between the first amplified signal and the second amplified signal to obtain a voltage sampling signal.

[0092] In the case of high-impedance input, the sampling signal of the voltage sampling module is small. Therefore, the voltage sampling module in the embodiment of the present application is provided with two-stage amplification. The first-stage amplification is the first amplifier G1 and the second amplifier G2, which respectively amplify the voltage signals of the two electrodes coupled to the impedance module. The second-stage amplification is the third amplifier G3. The two input ends of the third amplifier G3 are connected to the output end of the first amplifier G1 and the output end of the second amplifier G2, and are used to subtract and amplify the signals output by the first amplifier G1 and the second amplifier G2, and then output a voltage sampling signal. The voltage sampling module adopting a two-stage amplifier circuit can achieve high integration, and at the same time takes into account the functions of high-impedance input and signal amplification, and can process the input signal of the voltage sampling with a small voltage on the impedance module of the electromagnetic touch screen, and finally can output a voltage sampling signal of the voltage difference between the two electrodes.

[0093] Next, throughFigure 12 , Figure 13 and Figure 14 Illustrate the compositions of several voltage sampling modules by examples.

[0094] Refer to Figure 12 shown. The first amplifier G1, the second amplifier G2, and the third amplifier G3 are all fully differential operational amplifiers. The first amplifier G1 is represented as the first fully differential operational amplifier U11 in Figure 12 , the second amplifier G2 is represented as the second fully differential operational amplifier U21 in Figure 12 , and the third amplifier G3 is represented as the third fully differential operational amplifier U12 in Figure 12 . Among them:

[0095] The first fully differential operational amplifier U11 has a first differential input terminal, a second differential input terminal, and a first output terminal. The first differential input terminal is coupled to one of the two electrodes, and the second differential input terminal is connected to the reference voltage VCMII; the second fully differential operational amplifier U21 has a third differential input terminal, a fourth differential input terminal, and a second output terminal. The third differential input terminal is coupled to the other of the two electrodes, and the fourth differential input terminal is connected to the reference voltage VCMII; the third fully differential operational amplifier U12 has a fifth differential input terminal, a sixth differential input terminal, and a third output terminal. The fifth differential input terminal is used to receive the first amplified signal output from the first output terminal, the sixth differential input terminal is used to receive the second amplified signal output from the second output terminal, and the third output terminal is used to output a voltage sampling signal.

[0096] Take Figure 12 the coil formed by the electrode Rx0 and the electrode Rx1 in Figure 12 as an example. An impedance module (represented as a resistor R in

[0097] is terminated between the electrode Rx0 and the electrode Rx1. The first differential input terminal of the first fully differential operational amplifier U11 and the third differential input terminal of the second fully differential operational amplifier U21 are respectively connected to the electrode Rx0 and the electrode Rx1. Among them, the first differential input terminal of the first fully differential operational amplifier U11 is connected to the voltage source VCMI through the pull-up resistor R11, and the third differential input terminal of the second fully differential operational amplifier U21 is connected to the voltage source VCMI through the pull-up resistor R21. The pull-up resistors R11 and R12 are used to provide current bias for the first fully differential operational amplifier U11 and the second fully differential operational amplifier U21, and at the same time suppress high-frequency interference signals in the coupled space of the driving coil and the sensing coil. The second differential input terminal of the first fully differential operational amplifier U11 is connected to the reference voltage VCMII through the resistor R12, and the fourth differential input terminal of the second fully differential operational amplifier U21 is connected to the reference voltage VCMII through the resistor R22.The first output terminal of the first fully differential operational amplifier U11 includes two output terminals. One of the output terminals is connected to the fifth differential input terminal of the third fully differential operational amplifier U12 through the resistor R14, and the other output terminal is connected to the sixth differential input terminal of the third fully differential operational amplifier U12 through the resistor R15. The resistors R12, R13 and the capacitor C11 of the first fully differential operational amplifier U11 determine the amplification gain. Among them, the capacitance value of the capacitor C11 is very small, and its function is to filter out high-frequency noise outside the band (the capacitor C11 can also not be added to the circuit of the first fully differential operational amplifier U11). Therefore, the in-band gain of the first fully differential operational amplifier U11 can be considered as k1 = R13 / R12 + 1. Similarly, the second output terminal of the second fully differential operational amplifier U21 includes two output terminals. One of the output terminals is connected to the sixth differential input terminal of the third fully differential operational amplifier U12 through the resistor R18, and the other output terminal is connected to the fifth differential input terminal of the third fully differential operational amplifier U12 through the resistor R19. The resistors R22, R23 and the capacitor C21 of the second fully differential operational amplifier U21 determine the amplification gain. Among them, the capacitance value of the capacitor C21 is very small, and its function is to filter out high-frequency noise outside the band (the capacitor C21 can also not be added to the circuit of the second fully differential operational amplifier U21). Therefore, the in-band gain of the second fully differential operational amplifier U21 can be considered as k2 = R23 / R22 + 1. In order to facilitate the electromagnetic touch sensing device to analyze the voltage signal envelope, the gain k1 of the first fully differential operational amplifier U11 can be set to be the same as the gain k2 of the second fully differential operational amplifier U21. In this way, the signals amplified by the same amplification factor on the electrodes Rx0 and Rx1 can be output to the third fully differential operational amplifier U12.

[0098] The third fully differential operational amplifier U12 mainly subtracts the signals output by the first fully differential operational amplifier U11 and the second fully differential operational amplifier U21. In this way, the voltage signal across the impedance module is taken out, that is, the voltage difference signal between the electrodes Rx0 and Rx1 is output. Among them, the third output terminal of the third fully differential operational amplifier U12 includes two output terminals, and the two output terminals are respectively fed back to the fifth differential input terminal and the sixth differential input terminal through the resistors R16 and R17, and the capacitor C12 is set in parallel with the resistor R16, and the capacitor C13 is set in parallel with the capacitor R17. Assuming that the resistor values R14 = R15 = R18 = R19, and the capacitance values of the capacitors C12 and C13 are very small, and their function is to filter out high-frequency noise outside the band (the capacitors C12 and C13 can also not be added to the circuit of the third fully differential operational amplifier U12), then the in-band amplification factor of the third fully differential operational amplifier U12 is k3 = R16 / R14.

[0099] Through the two-stage amplified differential circuit composed of the above-mentioned fully differential operational amplifiers, the voltage acquisition of both ends of the impedance module can be realized. By utilizing the characteristics of the fully differential operational amplifier to maximize the differential-mode gain and minimize the common-mode gain, a high common-mode rejection ratio can be achieved in the circuit, thereby reducing the interference of external noise and improving the signal accuracy of the voltage sampling module.

[0100] The above example is for the voltage sampling module between electrode Rx0 and electrode Rx1. For the voltage sampling modules corresponding to other electrodes, such as the voltage sampling module between electrode Rx1 and electrode Rx2, it also includes the first amplifier G1, the second amplifier G2, and the third amplifier G3, and the three are respectively represented as the fourth fully differential amplifier U31, the second fully differential amplifier U21, and the fifth fully differential amplifier U22 in Figure 12 Among them, the aforementioned second fully differential amplifier U21 is reused for the coil of electrode Rx1 & electrode Rx2. The second fully differential operational amplifier U21 and the fourth fully differential amplifier U31 corresponding to electrode Rx2 are used as one-stage amplification to input the amplified signal to the fifth fully differential amplifier U22, and the fifth fully differential amplifier U22 outputs the voltage difference signal between electrode Rx1 and electrode Rx2 at a certain amplification factor.

[0101] Referring to Figure 13 As shown, the first amplifier G1, the second amplifier G2, and the third amplifier G3 are all single-ended operational amplifiers. The first amplifier G1 is represented as the first single-ended operational amplifier U11 in Figure 13 The second amplifier G2 is represented as the second single-ended operational amplifier U12 in Figure 13 The third amplifier G3 is represented as the third single-ended operational amplifier U13 in Figure 13 Among them:

[0102] The first single-ended operational amplifier U11 has a first non-inverting input terminal, a first inverting input terminal, and a first output terminal. The first non-inverting input terminal is coupled to one of the two electrodes, and the first inverting input terminal is connected to the reference voltage VCMII; the second single-ended operational amplifier U12 has a second non-inverting input terminal, a second inverting input terminal, and a second output terminal. The second non-inverting input terminal is coupled to the other of the two electrodes, and the second inverting input terminal is connected to the reference voltage VCMII; the third single-ended operational amplifier U13 has a third non-inverting input terminal, a third inverting input terminal, and a third output terminal. The third non-inverting input terminal is used to receive the first amplified signal output from the first output terminal, the third inverting input terminal is used to receive the second amplified signal output from the second output terminal, and the third output terminal is used to output the voltage sampling signal.

[0103] Taking Figure 13 the coil formed by electrode Rx0 and electrode Rx1 in Figure 13(represented as resistor R in the figure), the first non-inverting input terminal of the first single-ended operational amplifier U11 and the second non-inverting input terminal of the second single-ended operational amplifier U12 are respectively connected to the electrode Rx0 and the electrode Rx1. Among them, the first non-inverting input terminal of the first single-ended operational amplifier U11 is connected to the voltage source VCMI through the pull-up resistor R1, and the second non-inverting input terminal of the second single-ended operational amplifier U12 is connected to the voltage source VCMI through the pull-up resistor R3. The pull-up resistors R1 and R3 are used to provide current bias for the first single-ended operational amplifier U11 and the second single-ended operational amplifier U12, and at the same time suppress the high-frequency interference signals in the coupled space of the drive coil and the sense coil. The first inverting input terminal of the first single-ended operational amplifier U11 is connected to the reference voltage VCMII through the resistor R2, and the second inverting input terminal of the second single-ended operational amplifier U12 is connected to the reference voltage VCMII through the resistor R4.

[0104] The first output terminal of the first single-ended operational amplifier U11 is connected to the third non-inverting input terminal of the third single-ended operational amplifier U13 through the resistor R7. The third non-inverting input terminal of the third single-ended operational amplifier U13 is also connected to the voltage source VCMI through the pull-up resistor R6. The resistors R2 and R10 of the first single-ended operational amplifier U11 determine the amplification gain. Therefore, the in-band gain of the first single-ended operational amplifier U11 can be considered as k1 = R10 / R2 + 1. Similarly, the second output terminal of the second single-ended operational amplifier U12 is connected to the third inverting input terminal of the third single-ended operational amplifier U13 through the resistor R8. The second output terminal of the second single-ended operational amplifier U12 is also connected to the third input terminal of the third single-ended operational amplifier U13 through the resistors R8 and R9. The resistors R4 and R5 of the second single-ended operational amplifier U12 determine the amplification gain. Therefore, the in-band gain of the second single-ended operational amplifier U12 can be considered as k2 = R5 / R4 + 1. In order to facilitate the analysis of the voltage signal envelope of the electromagnetic touch sensing device, the gain k1 of the first single-ended operational amplifier U11 can be set to be the same as the gain k2 of the second single-ended operational amplifier U12. In this way, the signals amplified by the same amplification factor on the electrodes Rx0 and Rx1 can be output to the third single-ended operational amplifier U13.

[0105] The third single-ended operational amplifier U13 mainly subtracts the signals output by the first single-ended operational amplifier U11 and the second single-ended operational amplifier U12. In this way, the voltage signal across the impedance module is taken out, that is, the voltage difference signal between the electrodes Rx0 and Rx1 is output. Among them, the third output terminal of the third single-ended operational amplifier U13 is feedback to the third inverting input terminal through the resistor R9. Assuming that the resistor values R7 = R8 and R6 = R9, the in-band amplification factor of the third single-ended operational amplifier U13 is k3 = R9 / R8.

[0106] Through the above two-stage amplified differential circuit composed of single-ended operational amplifiers, the voltage acquisition of both ends of the impedance module can be realized. By using the characteristics of simple structure and low cost of the single-ended amplifier, the volume of the electromagnetic touch sensing device can be reduced and the material cost can be lowered.

[0107] The above example is for the voltage sampling module between electrode Rx0 and electrode Rx1. For the voltage sampling modules corresponding to other electrodes, such as the voltage sampling module between electrode Rx1 and electrode Rx2, it also includes the first amplifier G1, the second amplifier G2, and the third amplifier G3, and the three are respectively Figure 13 represented as the fourth single-ended amplifier U21, the fifth single-ended amplifier U22, and the sixth single-ended amplifier U23 in []. For example, the fourth single-ended amplifier U21 and the fifth single-ended amplifier U22 corresponding to electrode Rx1 & electrode Rx2 are used as the first-stage amplification to input the amplified signal to the sixth single-ended amplifier U23, and the sixth single-ended amplifier U23 outputs the voltage difference signal between electrode Rx1 and electrode Rx2 at a certain amplification factor.

[0108] It should be noted that although Figure 13 each of the above sensing coils is correspondingly provided with the first amplifier G1, the second amplifier G2, and the third amplifier G3, it can be seen that the signal of electrode Rx1 is not only given to the second amplifier G2 in coil Rx0&Rx1, but also given to the first amplifier G1 in coil Rx1&Rx2. The structures (including the resistance values of the surrounding resistors) of these two amplifiers can actually be the same. Therefore, in some possible embodiments, the above Figure 13 can reduce the number of single-ended operational amplifiers. Replace the second amplifier G2 in coil Rx0&Rx1 and the first amplifier G1 in coil Rx1&Rx2 with a single operational amplifier. The non-inverting input terminal of this operational amplifier is connected to electrode Rx1, the inverting input terminal is connected to the voltage source VCMI through a resistor, and the output terminal is divided into two paths. One path is given to the third amplifier G3 in coil Rx0&Rx1, and the other path is given to the third amplifier G3 in coil Rx1&Rx2, which can also realize the output of the voltage difference signal at both ends of the impedance module.

[0109] Referring to Figure 14 as shown, the first amplifier G1, the second amplifier G2, and the third amplifier G3 are all single-ended operational amplifiers and are connected to form the structure of an instrumentation operational amplifier. The first amplifier G1 is Figure 14 represented as the first single-ended operational amplifier U11 in []. The second amplifier G2 is Figure 14 represented as the second single-ended operational amplifier U12 in []. The third amplifier G3 is Figure 14 represented as the third single-ended operational amplifier U13 in []. Among them:

[0110] The first single-ended operational amplifier U11 has a first non-inverting input terminal, a first inverting input terminal, and a first output terminal. The second single-ended operational amplifier U12 has a second non-inverting input terminal, a second inverting input terminal, and a second output terminal. The first non-inverting input terminal is coupled to one of the two electrodes, the second non-inverting input terminal is coupled to the other of the two electrodes, and the first inverting input terminal is coupled to the second inverting input terminal. The third single-ended operational amplifier U13 has a third non-inverting input terminal, a third inverting input terminal, and a third output terminal. The third non-inverting input terminal is used to receive the second amplified signal output by the second output terminal, the third inverting input terminal is used to receive the first amplified signal output by the first output terminal, and the third output terminal is used to output a voltage sampling signal.

[0111] Taking Figure 14 the coil formed by the middle electrode Rx0 and the electrode Rx1 as an example, an impedance module is terminated between the electrode Rx0 and the electrode Rx1 ( Figure 14(represented as resistor R in the figure), the first non-inverting input terminal of the first single-ended operational amplifier U11 and the second non-inverting input terminal of the second single-ended operational amplifier U12 are respectively connected to the electrode Rx0 and the electrode Rx1. Among them, the first non-inverting input terminal of the first single-ended operational amplifier U11 is connected to the voltage source VCMI through the pull-up resistor R1, and the second non-inverting input terminal of the second single-ended operational amplifier U12 is connected to the voltage source VCMI through the pull-up resistor R9. The pull-up resistors R1 and R9 are used to provide current bias for the first single-ended operational amplifier U11 and the second single-ended operational amplifier U12, and at the same time suppress the high-frequency interference signals in the coupling space of the drive coil and the sense coil. A resistor is set between the first inverting input terminal of the first single-ended operational amplifier U11 and the second single-ended operational amplifier U12, which is composed of the resistor R2, the resistor R3, and the resistor R4. The first output terminal of the first single-ended operational amplifier U11 is connected to the first inverting input terminal through the resistor R3, and the second output terminal of the second single-ended operational amplifier U12 is connected to the second inverting input terminal through the resistor R4. A resistor R2 is set between the first inverting input terminal and the second inverting input terminal. The output terminals of the two first-stage amplifications (G1 and G2) of the instrumentation operational amplifier are connected to the two input terminals of the third single-ended operational amplifier U13. Among them, the first output terminal of the first single-ended operational amplifier U11 is connected to the third inverting input terminal of the third single-ended operational amplifier U13 through the resistor R5, and the second output terminal of the second single-ended operational amplifier U12 is connected to the third non-inverting input terminal of the third single-ended operational amplifier U13 through the resistor R6. The third output terminal of the third single-ended operational amplifier U13 is also connected to the third inverting input terminal through the resistor R7, and the third non-inverting input terminal is also connected to the voltage source VCMI through the resistor R8. The above three single-ended amplifiers and the resistor network composed of each resistor form an instrumentation amplifier. The instrumentation amplifier determines the gain based on the internal resistor network. Assuming that the resistor values R3 = R4, R5 = R6, and R7 = R8, then the in-band amplification factor of the third single-ended operational amplifier U13 is k = (1 + 2 * R3 / R2) * R7 / R5,

[0112] Through the instrumentation operational amplifier composed of the above single-ended operational amplifiers, the acquisition of the voltages at both ends of the impedance module can be realized. The instrumentation operational amplifier uses an internal feedback resistor network, which is isolated from the signal input terminal. Therefore, when input signals are applied to the two differential input terminals of the instrumentation amplifier, its gain can be preset internally or set externally by connecting an internal or external gain resistor through pins. The gain resistor is also isolated from the signal input terminal. Therefore, it has the advantages of high common-mode rejection ratio, high input impedance, low noise, etc., and improves the signal accuracy of the voltage sampling module.

[0113] It can be understood that the above Figure 12 are all fully differential operational amplifiers, and the above Figure 13 and Figure 14They are all single - ended amplifiers. However, in practical applications, multiple different types of operational amplifiers can be combined for use, as long as they can meet the functions of primary signal amplification and secondary differential operation. For example Figure 12 In Figure 12 , the first amplifier G1 and the second amplifier G2 use single - ended operational amplifiers, and the third amplifier G3 uses a fully differential operational amplifier. The output terminals of the two single - ended operational amplifiers are connected to the input terminals of the fully differential operational amplifier, and then a signal of the voltage difference across the impedance module is output at the output terminal of the fully differential operational amplifier.

[0114] In summary, the electromagnetic touch - sensing device provided by the embodiment of the present application is used to sense the signal of the electromagnetic touch screen to determine the position of the electromagnetic pen. The electromagnetic touch screen coupled to the electromagnetic touch - sensing device has multiple electrodes extending along the first direction. Adjacent two electrodes form a sensing coil arranged in the first direction. The embodiment of the present application couples at least two electrodes through an impedance module, so that a loop is formed between the two coupled electrodes. Then, a voltage sampling module is used to collect the voltage on the impedance module, and a voltage signal reflecting the magnitude of the current in the loop of the two electrodes can be obtained. Since the current directions in the sensing coils are the same, the direction of the voltage on the impedance module between the two electrodes is determined. Therefore, the position of the electromagnetic pen can be reflected by the position of the maximum voltage. Compared with the sampling method in which direct current sampling leads to opposite current directions on the electrodes multiplexed between adjacent sensing coils and the position of the electromagnetic pen cannot be determined by the position of the maximum current signal, the embodiment of the present application can accurately determine the position of the electromagnetic pen through the voltage sampling signal of the voltage sampling module.

[0115] The embodiment of the present application also provides a screen assembly, including the electromagnetic touch - sensing device in any of the above - mentioned embodiments, and the electromagnetic touch - sensing device is coupled to the electromagnetic touch screen.

[0116] The screen assembly adopts the structure as shown in Figure 3 The electromagnetic touch screen has multiple electrodes, which are sequentially denoted as Rx0, Rx1, Rx2, Rx3,..., Rxn from top to bottom. Each Rx electrode is short - circuited on the left side in Figure 3 and is connected to the flexible cable interface provided by the electromagnetic touch screen on the right side in Figure 3 The flexible cable interface of the electromagnetic touch screen is connected to the flexible cable interface of the electromagnetic touch - sensing device through a flexible cable. Among them, adjacent two Rx electrodes are short - circuited on the left side to form a sensing coil. Therefore, there is a common electrode Rx between adjacent sensing coils, forming a sensing coil with a comb - like structure.

[0117] The electromagnetic touch sensing device includes an impedance module, a voltage sampling module, and a control module. The impedance module has a plurality of resistors R, and the number of these resistors R corresponds to the number of sensing coils. When connected to the cable interface of the electromagnetic touch screen through a cable, the impedance module is coupled to the sensing coils of the electromagnetic touch screen through the wires in the cable, so that both ends of each resistor in the impedance module are coupled to two electrodes Rx in each sensing coil, forming a circuit structure as shown in Figure 5 shown. The voltage sampling module has a plurality of voltage differential sampling modules, and each voltage differential sampling module is connected in parallel with each resistor R in the impedance module, and is used to collect the voltage difference between the two electrodes Rx of the sensing coil corresponding to the resistor R and output a voltage sampling signal corresponding to the voltage difference. Specifically, the voltage sampling module includes a first amplifier, a second amplifier, and a third amplifier. The first amplifier is coupled to one electrode Rx of the sensing coil, the second amplifier is coupled to the other electrode Rx of the sensing coil, the output ends of the first amplifier and the second amplifier are connected to the two input ends of the third amplifier, and the output end of the third amplifier is connected to the control module. The first amplifier is used to amplify the signal of one electrode Rx of the sensing coil and input it into the third amplifier. The second amplifier is used to amplify the signal of the other electrode Rx of the sensing coil and input it into the third amplifier. The third amplifier subtracts the two input signals and outputs a differential signal, that is, a voltage sampling signal. The control module performs voltage signal envelope analysis according to the voltage sampling signal to determine which sensing coil the electromagnetic pen is above.

[0118] When the electromagnetic pen emits a magnetic field signal to the electromagnetic touch screen through the internal resonance circuit, the sensing coils in a region of the electromagnetic touch screen close to the electromagnetic pen will induce current. At this time, the direction of the current in the sensing coils is the same. However, since there is a common electrode Rx between adjacent sensing coils, in order to avoid the uncertain situation that the current on the common electrode Rx is positive and negative or zero, the solution of the embodiment of the present application is adopted to change the traditional current acquisition to the voltage acquisition at both ends of the impedance module. Since the direction of the voltage at both ends of the impedance module is determined, and the magnitude of the voltage at both ends of the impedance module is positively correlated with the magnitude of the induced current in the sensing coil, the magnitude of the current on the sensing coil can be reflected by the voltage, and then the position of the electromagnetic pen can be determined by the maximum value of the voltage signal envelope, and then the corresponding position of the electromagnetic pen on the screen can be presented on the electromagnetic touch screen.

[0119] In some possible embodiments, the above screen assembly further includes a capacitive touch screen, which is coupled with the electromagnetic touch screen in a single screen to form a touch screen with a multi-layer structure, and this touch screen is coupled and connected to the above electromagnetic touch sensing device. The capacitive touch screen can be located on the upper layer of the electromagnetic touch screen (in this case, the coils of the capacitive touch screen and the electromagnetic touch screen are independently arranged in two layers), or can be in the same layer as the electromagnetic touch screen (in this case, the coils of the capacitive touch screen and the electromagnetic touch screen may be reused). Thus, in this embodiment, the screen assembly can implement capacitive touch functions, such as being suitable for direct touch by fingers or capacitive pens, and can also implement electromagnetic touch functions, such as being suitable for electromagnetic pen touch.

[0120] The embodiment of the present application further provides an electronic device, including the above screen assembly. The screen assembly serves as the input unit and display unit of the electronic device. During the process of the user touching the screen assembly with an electromagnetic pen, the screen assembly receives the magnetic field signal emitted by the electromagnetic pen and induces a current in the internal sensing coil. The electromagnetic touch sensing device of the screen assembly can obtain a voltage sampling signal reflecting the magnitude of the induced current in each sensing coil by collecting the voltage of the impedance module terminated to the sensing coil, and then determine the position of the electromagnetic pen according to the magnitude of the voltage sampling signal, and then send a display signal to the screen assembly, so that the screen assembly presents display content corresponding to the position of the electromagnetic pen under the drive of the display signal.

[0121] The embodiment of the present application further provides a touch system, including the above electronic device and an electromagnetic pen.

[0122] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0123] It should be understood that in this application, "at least one (item)" means one or more, and "a plurality" means two or more. "And / or" is used to describe the relationship between associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist simultaneously. Here, A and B can be singular or plural. The character " / " generally indicates an "or" relationship between the associated objects before and after. "At least one (or more) of the following" or its similar expressions refer to any combination of these items, including any combination of single items (or more) or plural items (or more). For example, at least one (or more) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or plural.

[0124] It should be understood that in the description of the embodiments of this application, the meaning of "a plurality (or multiple items)" is more than two. Understandings such as greater than, less than, exceeding, etc. do not include the present number, and understandings such as above, below, within, etc. include the present number.

[0125] In several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of units is only a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces, and the indirect coupling or communication connection of devices or units can be in electrical, mechanical, or other forms.

[0126] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0127] In addition, each functional unit in the various embodiments of this application can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0128] It should also be understood that the various implementation manners provided in the embodiments of this application can be combined arbitrarily to achieve different technical effects.

[0129] The above is a specific description of the preferred embodiment of the present application. However, the present application is not limited to the above-mentioned embodiments. Those skilled in the art can make various equivalent deformations or substitutions without violating the spirit of the present application, and these equivalent deformations or substitutions are all included within the scope defined by the claims of the present application.

Claims

1. An electromagnetic touch sensing device, characterized in that, For coupling to an electromagnetic touch screen, the electromagnetic touch screen includes a plurality of electrodes extending in a first direction, and adjacent two of the electrodes form a sensing coil. By the electromagnetic touch sensing device sensing the changes in the electromagnetic fields of the sensing coils caused by an electromagnetic pen on the electromagnetic touch screen, the position of the electromagnetic pen is sensed; The electromagnetic touch sensing device includes: An impedance module for coupling at least two of the electrodes; A voltage sampling module for sampling the voltage on the impedance module.

2. The electromagnetic touch sensing device according to claim 1, wherein, Couple the impedance module between every two adjacent electrodes.

3. The electromagnetic touch sensing device according to claim 1, wherein Couple the impedance module between two non-adjacent electrodes, and a predetermined number of electrodes are spaced between the two non-adjacent electrodes.

4. The electromagnetic touch sensing device according to claim 1, wherein Couple the impedance module between two non-adjacent electrodes, and the number of electrodes spaced between the two non-adjacent electrodes is not fixed.

5. The electromagnetic touch sensing device according to claim 1, characterized in that, The electromagnetic touch screen further includes a plurality of drive coils arranged in a second direction, the second direction being perpendicular to the first direction. Among them, drive each of the drive coils, so that the electromagnetic touch sensing device senses the changes in the electromagnetic fields of the overlapping portions of the sensing coils and the currently driven drive coil, to sense the position of the electromagnetic pen.

6. The electromagnetic touch sensing device according to claim 5, wherein The electromagnetic touch sensing device further includes a switching device, the switching device being connected in series with the impedance module. Among them, in the case where the switching device is turned off, the sensing coil serves as the drive coil.

7. The electromagnetic touch sensing device according to claim 1, wherein The electromagnetic touch sensing device further includes a control module, the control module being coupled to the output end of the voltage sampling module, and being configured to determine the position of the electromagnetic pen according to the voltage sampling signal output by the voltage sampling module.

8. The electromagnetic touch sensing device according to claim 1, wherein The impedance module includes a resistor network, the resistor network includes at least one resistor, and the resistor network is used to couple the two electrodes.

9. The electromagnetic touch sensing device according to claim 8, wherein, The impedance module further includes a capacitor connected in series or in parallel with any one of the resistors.

10. The electromagnetic touch sensing device according to claim 9, wherein, The structure of the impedance module adopts one of the following: The resistor network includes a first resistor, and the impedance module further includes a first capacitor connected in parallel with the first resistor; The resistor network includes a second resistor and a third resistor connected in series, and the impedance module further includes a second capacitor connected in parallel with the second resistor; The resistor network includes a fourth resistor and a fifth resistor connected in parallel, and the impedance module further includes a third capacitor connected in series with the fourth resistor.

11. The electromagnetic touch sensing device according to claim 1, wherein, The voltage sampling module includes a first amplifier, a second amplifier, and a third amplifier, where The first amplifier amplifies the voltage of one of the two electrodes to generate a first amplified signal; The second amplifier amplifies the voltage of the other of the two electrodes to generate a second amplified signal; The third amplifier amplifies the differential signal between the first amplified signal and the second amplified signal to obtain a voltage sampling signal.

12. The electromagnetic touch sensing device according to claim 11, wherein, The first amplifier, the second amplifier, and the third amplifier are all fully differential operational amplifiers, where The first amplifier has a first differential input terminal, a second differential input terminal, and a first output terminal. The first differential input terminal is coupled to one of the two electrodes, and the second differential input terminal is connected to a reference voltage. The second amplifier has a third differential input terminal, a fourth differential input terminal, and a second output terminal. The third differential input terminal is coupled to the other of the two electrodes, and the fourth differential input terminal is connected to a reference voltage. The third amplifier has a fifth differential input terminal, a sixth differential input terminal, and a third output terminal. The fifth differential input terminal is used to receive the first amplified signal output from the first output terminal, the sixth differential input terminal is used to receive the second amplified signal output from the second output terminal, and the third output terminal is used to output the voltage sampling signal.

13. The electromagnetic touch sensing device according to claim 11, wherein, The first amplifier, the second amplifier, and the third amplifier are all single-ended operational amplifiers. Among them, The first amplifier has a first non-inverting input terminal, a first inverting input terminal, and a first output terminal. The first non-inverting input terminal is coupled to one of the two electrodes, and the first inverting input terminal is connected to a reference voltage. The second amplifier has a second non-inverting input terminal, a second inverting input terminal, and a second output terminal. The second non-inverting input terminal is coupled to the other of the two electrodes, and the second inverting input terminal is connected to a reference voltage. The third amplifier has a third non-inverting input terminal, a third inverting input terminal, and a third output terminal. The third non-inverting input terminal is used to receive the first amplified signal output from the first output terminal, the third inverting input terminal is used to receive the second amplified signal output from the second output terminal, and the third output terminal is used to output the voltage sampling signal.

14. The electromagnetic touch sensing device according to claim 11, wherein The first amplifier, the second amplifier, and the third amplifier are all single-ended operational amplifiers. Among them, The first amplifier has a first non-inverting input terminal, a first inverting input terminal, and a first output terminal. The second amplifier has a second non-inverting input terminal, a second inverting input terminal, and a second output terminal. The first non-inverting input terminal is coupled to one of the two electrodes, the second non-inverting input terminal is coupled to the other of the two electrodes, and the first inverting input terminal is coupled to the second inverting input terminal. The third amplifier has a third non-inverting input terminal, a third inverting input terminal, and a third output terminal. The third non-inverting input terminal is used to receive the second amplified signal output from the second output terminal, the third inverting input terminal is used to receive the first amplified signal output from the first output terminal, and the third output terminal is used to output the voltage sampling signal.

15. A screen component, characterized in that, Comprising the electromagnetic touch sensing device according to any one of claims 1 to 14, the electromagnetic touch sensing device is coupled to the electromagnetic touch screen.

16. The screen component according to claim 15, characterized in that, It further includes a capacitive touch screen, and the capacitive touch screen is coupled to the electromagnetic touch screen to which the electromagnetic touch sensing device is coupled.

17. An electronic device, characterized in that, Comprising the screen assembly according to claim 15 or 16.

18. A touch control system, characterized in that, Comprising the electronic device according to claim 17 and the electromagnetic pen.

Images