Infrared signal amplification circuit and infrared touch device

Abstract

Disclosed in embodiments of the present application are an infrared signal amplification circuit and an infrared touch device. The infrared signal amplification circuit comprises a plurality of first amplification units and a plurality of second amplification units; each first-stage amplification circuit in each first amplification unit is used for amplifying a first electric signal output by a corresponding infrared receiver to obtain a first amplified electric signal, and the infrared receiver receives an infrared signal on the basis of a control signal and outputs the corresponding first electric signal; each amplification reference circuit in each first amplification unit is used for generating, on the basis of the control signal, a second electric signal representing a reference; each second amplification unit is connected to each amplification reference circuit and a corresponding first-stage amplification circuit in each first amplification unit, and the second amplification unit is used for amplifying the first amplified electric signal on the basis of the second electric signal to obtain a second amplified electric signal. Use of the circuit can solve the technical problem in the related art that noise in an electric signal is synchronously amplified when an infrared touch device amplifies the electric signal.

Description

Infrared signal amplifying circuit and infrared touch device Technical Field

[0001] The embodiments of the present application relate to the field of infrared touch technology, and in particular to an infrared signal amplifying circuit and an infrared touch device. Background Art

[0002] In an external touch device, the infrared touch frame is a key component for realizing infrared touch control. The infrared touch frame is equipped with multiple infrared receivers and multiple infrared transmitters. The infrared receiver receives the infrared light emitted by the infrared transmitter according to the control signal of the processor and outputs a corresponding electrical signal. The electrical signal is amplified and then received and processed by the processor to identify the corresponding touch operation. Due to the interface limitations of the processor, the related art adopts an array-type method to connect the infrared receivers. For example, referring to Figure 1, it shows the connection relationship between the infrared receivers 12. For ease of understanding, Figure 1 shows the infrared receivers 12 in rows and columns, wherein the infrared receivers 12 in the same row share a control bus, and each control bus is connected to the processor to send the control signal generated by the processor to the infrared receiver 12. The infrared receivers 12 in the same column share a receiving bus, and each receiving bus is connected to the processor so that the processor receives the electrical signal generated by each infrared receiver 12 based on infrared light.

[0003] In the related art, to enhance the infrared light-related features in the electrical signal, infrared touch devices can first amplify the electrical signal generated by the infrared receiver before transmitting it to the processor for touch operation recognition. However, the electrical signal is accompanied by noise when it is transmitted within the infrared touch device. When the infrared touch device amplifies the electrical signal, the noise in the electrical signal is also amplified synchronously, which is not conducive to the processor's accurate processing of the electrical signal and, in turn, is not conducive to accurate touch operation recognition.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide an infrared signal amplifying circuit and an infrared touch device to solve the technical problem in the related art that when an infrared touch device amplifies an electrical signal, noise in the electrical signal is also synchronously amplified.

[0006] In a first aspect, an embodiment of the present application provides an infrared signal amplifying circuit, comprising: a plurality of first amplifying units and a plurality of second amplifying units, each of the first amplifying units comprising an amplifying reference circuit and a plurality of first-stage amplifying circuits,

[0007] Each of the first-stage amplifier circuits is connected to a corresponding infrared receiver and is configured to amplify a first electrical signal output by the infrared receiver to obtain a first amplified electrical signal. The infrared receiver receives an external infrared signal and outputs a corresponding first electrical signal according to a control signal. The control signal is transmitted by a corresponding control bus. Each of the first amplifier units corresponds to a control bus, and each of the control buses sequentially and cyclically transmits the control signal generated by the processor.

[0008] Each of the amplifying reference circuits is used to generate a second electrical signal according to the control signal, where the second electrical signal is a reference signal, and the second electrical signal and the first amplified electrical signal output by each first-stage amplifying circuit in the corresponding first amplifying unit form a differential signal;

[0009] Each second amplifying unit is connected to each amplifying reference circuit and to a corresponding first-stage amplifying circuit in each first amplifying unit. The second amplifying unit is used to amplify the first amplified electrical signal according to the second electrical signal to obtain a second amplified electrical signal.

[0010] In one embodiment of the present application, each of the second amplifying units includes a voltage follower circuit and a secondary amplifying circuit;

[0011] Each of the voltage follower circuits is connected to each of the amplifying reference circuits, and is configured to generate a third electrical signal according to the second electrical signal;

[0012] Each of the secondary amplifier circuits is connected to a corresponding voltage follower circuit and a corresponding primary amplifier circuit in each of the first amplifier units, and is configured to amplify the first amplified electrical signal according to the third electrical signal to obtain a second amplified electrical signal.

[0013] In one embodiment of the present application, the voltage follower circuit includes: a third resistor and a first operational amplifier,

[0014] The non-inverting input terminal of the first operational amplifier is respectively connected to the first receiving bus and the first end of the third resistor, the first receiving bus is respectively connected to each amplifying reference circuit to transmit the second electrical signal output by each amplifying reference circuit, the inverting input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, the output terminal of the first operational amplifier is also connected to the corresponding secondary amplifying circuit, and the second end of the third resistor is grounded.

[0015] In one embodiment of the present application, the secondary amplification circuit is a bandpass filter circuit, which includes: a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, and a second operational amplifier.

[0016] The first end of the fourth resistor is connected to the corresponding voltage follower circuit, the second end of the fourth resistor is respectively connected to the first end of the first capacitor and the first end of the second capacitor, the second end of the first capacitor is respectively connected to the first end of the fifth resistor and the inverting input terminal of the second operational amplifier, the second end of the second capacitor is respectively connected to the second end of the fifth resistor and the output terminal of the second operational amplifier, the first end of the sixth resistor is respectively connected to the corresponding second receiving bus and the first end of the seventh resistor, each second receiving bus is respectively connected to a corresponding first-stage amplifier circuit in each first amplification unit, the second end of the sixth resistor is respectively connected to the first end of the third capacitor and the first end of the fourth capacitor, the second end of the third capacitor is respectively connected to the non-inverting input terminal of the second operational amplifier and the first end of the eighth resistor, the second end of the eighth resistor and the second end of the fourth capacitor are connected and then connected to the second voltage, and the second end of the seventh resistor is grounded;

[0017] The output terminal of the second operational amplifier outputs the second amplified electrical signal.

[0018] In one embodiment of the present application, the second amplifying unit is a subtraction operational amplifier circuit, and the subtraction operational amplifier circuit includes: a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a sixth operational amplifier, a tenth capacitor, an eleventh capacitor, and a twelfth capacitor;

[0019] The first end of the 20th resistor and the first end of the 10th capacitor are connected and then connected to a first receiving bus, the first receiving bus being connected to each amplifying reference circuit respectively to transmit the second electrical signal output by each amplifying reference circuit; the second end of the 10th capacitor is connected to the first end of the 21st resistor and the first end of the 22nd resistor; the second end of the 22nd resistor is connected to the first end of the 11th capacitor, the first end of the 23rd resistor, and the inverting input terminal of the sixth operational amplifier; the second end of the 11th capacitor and the second end of the 23rd resistor are connected and then connected to the output terminal of the sixth operational amplifier;

[0020] The first end of the twenty-fourth resistor and the first end of the twelfth capacitor are connected to corresponding second receiving buses, each of the second receiving buses is connected to a corresponding first-stage amplifier circuit in each of the first amplifying units, the second end of the twelfth capacitor is connected to the first end of the twenty-fifth resistor and the first end of the twenty-sixth resistor, respectively, and the second end of the twenty-sixth resistor is connected to the non-inverting input terminal of the sixth operational amplifier;

[0021] The second end of the 20th resistor and the second end of the 24th resistor are both grounded, and the second end of the 21st resistor and the second end of the 25th resistor are both connected to a fifth voltage;

[0022] The output terminal of the sixth operational amplifier outputs the second amplified electrical signal.

[0023] In one embodiment of the present application, it further includes: a plurality of three-stage amplification circuits,

[0024] Each of the three-stage amplifying circuits is respectively connected to a second amplifying unit for amplifying the second amplified electrical signal to obtain a third amplified electrical signal.

[0025] In one embodiment of the present application, the three-stage amplification circuit includes: a fifth capacitor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, and a third operational amplifier;

[0026] The first end of the fifth capacitor is connected to the corresponding second amplifying unit, the second end of the fifth capacitor is respectively connected to the first end of the ninth resistor and the first end of the tenth resistor, the second end of the ninth resistor and the first end of the eleventh resistor are connected and then connected to a third voltage, the second end of the eleventh resistor is respectively connected to the first end of the twelfth resistor and the inverting input terminal of the third operational amplifier, the second end of the twelfth resistor is connected to the output terminal of the third operational amplifier, and the second end of the tenth resistor is connected to the non-inverting input terminal of the third operational amplifier;

[0027] The output terminal of the third operational amplifier outputs the third amplified electrical signal.

[0028] In one embodiment of the present application, the second amplified electrical signal is a sinusoidal wave signal, and the peak signal points and the trough signal points of the sinusoidal wave signal correspond to the sampling signal of the processor.

[0029] In one embodiment of the present application, the three-stage amplification circuit includes: a sixth capacitor, a seventh capacitor, an eighth capacitor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a first switch, a second switch, and a fourth operational amplifier.

[0030] A first end of the sixth capacitor is connected to the corresponding second amplifying unit, a second end of the sixth capacitor is respectively connected to the first end of the thirteenth resistor, the first end of the fourteenth resistor, and the first end of the fifteenth resistor, a second end of the fourteenth resistor is connected to the non-inverting input terminal of the fourth operational amplifier, a second end of the fifteenth resistor is respectively connected to the first end of the seventh capacitor and the first end of the sixteenth resistor, a second end of the sixteenth resistor is respectively connected to the inverting input terminal of the fourth operational amplifier and the first end of the eighth capacitor, a second end of the eighth capacitor is connected to the output terminal of the fourth operational amplifier, a first switch is further connected between the first and second ends of the eighth capacitor, a second switch is further connected between the first and second ends of the fifteenth resistor, and the second end of the thirteenth resistor and the first end of the seventh capacitor are respectively grounded;

[0031] The output terminal of the fourth operational amplifier outputs the third amplified electrical signal.

[0032] In one embodiment of the present application, the present invention further includes: a plurality of four-stage amplifier circuits,

[0033] Each of the three-stage amplification circuits is connected to the corresponding second amplification unit through a corresponding four-stage amplification circuit. The four-stage amplification circuit is used to amplify the second amplified electrical signal to obtain a fourth amplified electrical signal, and send the fourth amplified electrical signal to the three-stage amplification circuit so that the three-stage amplification circuit amplifies the fourth amplified electrical signal to obtain the third amplified electrical signal.

[0034] In one embodiment of the present application, the four-stage amplification circuit includes: a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a ninth capacitor, and a fifth operational amplifier.

[0035] A first end of the seventeenth resistor is connected to the corresponding second amplifying unit, a second end of the seventeenth resistor is connected to the non-inverting input terminal of the fifth operational amplifier, a first end of the eighteenth resistor is connected to the fourth voltage, a second end of the eighteenth resistor is respectively connected to the inverting input terminal of the fifth operational amplifier, the first end of the nineteenth resistor, and the first end of the ninth capacitor, and an output end of the fifth operational amplifier is respectively connected to the second end of the nineteenth resistor, the second end of the ninth capacitor, and the corresponding three-stage amplifying circuit;

[0036] The output terminal of the fifth operational amplifier outputs the fourth amplified electrical signal.

[0037] In one embodiment of the present application, the first-stage amplification circuit includes: a first resistor and a first transistor,

[0038] A first end of the first resistor is connected to a corresponding control bus, a second end of the first resistor is respectively connected to an anode of a photosensitive diode in an infrared receiver and a base of the first transistor, a cathode of the photosensitive diode in the infrared receiver is connected to the control bus, a collector of the first transistor is connected to a first voltage, an emitter of the first transistor is connected to a corresponding second receiving bus, each first-stage amplifier circuit in the first amplifying unit is respectively connected to a different second receiving bus, each second receiving bus is connected to a first-stage amplifier circuit in each first amplifying unit, and each second receiving bus is also respectively connected to a corresponding second amplifying unit;

[0039] The amplifying reference circuit includes: a second resistor and a second transistor,

[0040] The first end of the second resistor is connected to the corresponding control bus, the second end of the second resistor is connected to the base of the second transistor, the collector of the second transistor is connected to the first voltage, the emitter of the second transistor is connected to the first receiving bus, each of the amplification reference circuits is connected to the first receiving bus, and the first receiving bus is also respectively connected to each second amplification unit.

[0041] In a second aspect, an embodiment of the present application further provides an infrared touch device, comprising: a main board and a plurality of light strips, wherein the light strips are provided with at least one infrared receiver and at least one infrared transmitter, and the main board is provided with a processor and the infrared signal amplifying circuit as described in the first aspect.

[0042] The processor is used to control the infrared transmitter to transmit infrared signals externally, and to control the infrared receiver to receive external infrared signals, and the infrared receiver outputs a corresponding first electrical signal to the infrared signal amplifying circuit when receiving the external infrared signal;

[0043] The infrared signal amplifying circuit is used to amplify the first electrical signal.

[0044] In one embodiment of the present application, by setting a first-stage amplification circuit in the first amplification unit, the electrical signal output by the infrared receiver can be amplified to obtain a first amplified electrical signal. By setting an amplification reference circuit in the first amplification unit, a second electrical signal that can be used as a reference can be obtained while amplifying the electrical signal output by the infrared receiver. The noise signal in the second electrical signal and the noise signal in the first amplified electrical signal are common-mode signals. Therefore, when the first amplified electrical signal is amplified by the second amplification unit, the second electrical signal is referenced to effectively suppress the noise signal while amplifying the electrical signal. That is, the technical problem that the noise in the electrical signal is also synchronously amplified when the electrical signal is amplified is avoided, thereby improving the signal-to-noise ratio of the electrical signal and thereby improving the accuracy of subsequent touch operation recognition. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 is a connection diagram of an infrared receiver provided in the related art;

[0046] FIG2 is a schematic structural diagram of an infrared touch frame provided in the related art;

[0047] FIG3 is a schematic diagram of an optical network provided in the related art;

[0048] FIG4 is a schematic structural diagram of a triode amplifier circuit provided in the related art;

[0049] FIG5 is a schematic diagram of bias voltages of the transistor amplifier circuits connected to the receiving bus 1 in FIG4 ;

[0050] FIG6 is a schematic structural diagram of a two-stage amplifier circuit provided in the related art;

[0051] FIG. 7 is a schematic diagram of a three-stage amplifier circuit provided in the related art.

[0052] FIG8 is a schematic diagram comparing input and output signals of an integrating operational amplifier circuit provided in the related art;

[0053] FIG9 is a schematic structural diagram of an infrared signal amplifying circuit provided by one embodiment of the present application;

[0054] FIG10 is a schematic structural diagram of another infrared signal amplifying circuit provided by one embodiment of the present application;

[0055] FIG11 is a schematic structural diagram of a second amplifying unit provided in one embodiment of the present application;

[0056] FIG12 is a schematic structural diagram of another second amplifying unit provided in one embodiment of the present application;

[0057] FIG13 is a schematic structural diagram of a first amplifying unit provided in one embodiment of the present application;

[0058] FIG14 is a schematic structural diagram of yet another infrared signal amplifying circuit provided by an embodiment of the present application;

[0059] FIG15 is a schematic structural diagram of a three-stage amplifier circuit provided by one embodiment of the present application;

[0060] FIG16 is a waveform diagram provided by an embodiment of the present application;

[0061] FIG17 is another waveform diagram provided by an embodiment of the present application;

[0062] FIG18 is a schematic structural diagram of another three-stage amplifier circuit provided by one embodiment of the present application;

[0063] FIG19 is a schematic structural diagram of another infrared signal amplifying circuit provided by an embodiment of the present application;

[0064] FIG20 is a schematic structural diagram of a four-stage amplifier circuit provided in one embodiment of the present application. DETAILED DESCRIPTION

[0065] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended to explain the present application, not to limit the present application. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present application, not all structures.

[0066] An infrared touch device can be understood as a device that uses infrared touch detection and includes at least an infrared touch frame to enable touch detection through the infrared touch frame. It is understood that an infrared touch device may only include an infrared touch frame. In this case, the infrared touch device can be used in conjunction with other devices to enable the other devices to have infrared touch functionality. For example, an infrared touch device can be integrated into a smart TV to enable the smart TV to have infrared touch functionality. An infrared touch device can also be an electronic device with infrared touch functionality, such as a display device with infrared touch functionality (such as an interactive tablet with infrared touch functionality).

[0067] Figure 2 is a schematic diagram of the structure of an infrared touch frame provided in the related art. Referring to Figure 2, the infrared touch frame 10 is composed of multiple light strips 11, each of which can be equipped with multiple infrared receivers 12 or multiple infrared emitters 13. Figure 2 illustrates an example in which a single light strip 11 is equipped with two infrared elements of the same type, meaning that some light strips 11 are equipped with two infrared receivers 12, and some are equipped with two infrared emitters 13.

[0068] The material of the light strip 11 and the method of mounting the infrared emitters 12 and 13 on the light strip 11 are currently not limited. The light strips 11 are arranged into a rectangular shape to form the infrared touch frame 10. The light strips 11 mounting the infrared emitters 13 are located on two adjacent sides of the infrared touch frame 10, while the light strips 11 mounting the infrared receivers 12 are located on the other two adjacent sides of the infrared touch frame 10.

[0069] Infrared receiver 12 is an infrared element capable of receiving infrared light. Here, we describe an infrared receiving lamp as an example. The infrared receiving lamp includes a diode capable of receiving infrared radiation, such as a photodiode. The photodiode receives infrared light and outputs a corresponding electrical signal. Currently, the infrared light received by the photodiode can be considered an infrared signal within the reception range of infrared receiver 12.

[0070] The infrared emitter 13 is an infrared element that can emit infrared light. Currently, the infrared emitter 13 is described as an infrared emitting lamp. The infrared emitting lamp includes a light emitting diode that can emit infrared radiation, and emits infrared light through the light emitting diode.

[0071] Figure 3 is a schematic diagram of an optical network provided in the related art. Referring to Figure 3, the infrared light emitted by an infrared transmitter 13 can be received by multiple infrared receivers 12. Similarly, one infrared receiver 12 can receive infrared light emitted by multiple infrared transmitters 13. At this time, the infrared light between an infrared transmitter 13 and a corresponding infrared receiver 12 can be visualized as an infrared ray. Each infrared ray forms an optical network in the infrared touch frame 10 and is used for touch detection.

[0072] Exemplarily, the infrared touch frame 10 further includes a mainboard 14. The mainboard 14 can be integrated with the light strips 11 or independently provided with each light strip 11. For example, when the infrared touch device is an electronic device, the mainboard of the infrared touch frame 10 and the mainboard of the electronic device can be integrated into one mainboard, that is, the infrared touch frame and the electronic device share the same mainboard. Figure 2 illustrates an example in which the mainboard 14 is integrated with a light strip 11.

[0073] The mainboard 14 is installed with one or more processors. Currently, the mainboard 14 is described as having one processor installed thereon, and the processor is a microcontroller unit (MCU).

[0074] The MCU controls the infrared emitter 13 to emit infrared light and the infrared receiver 12 to receive infrared light. For example, when the MCU sends a signal to the infrared emitter 13, the infrared emitter 13 emits infrared light. When the MCU sends another signal to the infrared receiver 12, the infrared receiver 12 receives (or captures) the infrared signal in the environment and outputs a corresponding electrical signal. Generally speaking, the electrical signal output by the infrared receiver 12 varies depending on the intensity of the infrared light.

[0075] The MCU is also used to process the electrical signal generated by the infrared receiver 12 based on the infrared signal. For example, the MCU includes an analog to digital converter (ADC) module, which is used to convert the analog electrical signal generated by the infrared receiver 12 into a digital signal to facilitate subsequent recognition of touch operations and determination of touch positions.

[0076] Since there are a large number of infrared receivers 12 and a limited number of ADC modules in the MCU, it is not possible to directly connect the ADC modules to all of the infrared receivers 12. Furthermore, since the MCU has a limited number of interfaces for sending control signals to the infrared receivers 12, it is also not possible to directly connect the MCU to all of the infrared receivers 12. Therefore, the connection between the MCU and the infrared receivers 12 can be implemented in an array configuration, such as the array configuration shown in FIG1 .

[0077] In an array connection, infrared receivers 12 in the same row are connected to the same control bus, with each row corresponding to a different control bus. Each control bus is connected to an interface in the MCU for sending control signals. In this case, the MCU can use a shift register method to send control signals. Specifically, each control signal is sent to a control bus at a time, so that each infrared receiver 12 connected to that control bus receives infrared signals from the environment while receiving the control signal. After each control bus cyclically transmits the control signal, all infrared receivers 12 can scan the environment for infrared signals at a frequency related to the frequency at which the MCU sends the control signal.

[0078] In an array connection, infrared receivers 12 in the same column are connected to the same receive bus, and each receive bus is connected to the ADC sampling circuit corresponding to the ADC module in the MCU. Generally speaking, an MCU can be equipped with 2 to 3 ADC modules, and these 2 to 3 ADC modules can be connected to approximately 10 ADC sampling circuits. In other words, a total of approximately 10 ADC sampling circuits can sample the electrical signals generated by the infrared receivers 12. In this case, the number of receive buses can reach approximately 10, which can meet the application requirements of the general infrared touch frame 10. It should be noted that while FIG2 shows an example of receive bus 15, in actual applications, the number of receive buses 15 can be 3-10.

[0079] Based on the array-type connection, each receiving bus transmits the electrical signal generated by the infrared receivers 12 in the same row at the same time, and each receiving bus transmits the electrical signal generated by the corresponding infrared receiver 12 in each column in sequence according to the order in which the control bus transmits the control signal. That is, the MCU controls each infrared receiver 12 to scan sequentially row by row to obtain the corresponding electrical signal.

[0080] It should be noted that the current description mainly focuses on the control process of the MCU for the infrared receiver 12. The control process of the MCU for the infrared transmitter 13 is not described at present. You can refer to the implemented technology. It only needs to meet the requirements that each infrared light in the infrared touch frame 10 is scanned at a certain frequency.

[0081] To facilitate understanding of the technical solution, the following describes the touch detection process of the infrared touch frame 10, using its application to a display screen as an example. The infrared touch frame 10 is used to detect touch operations on the display screen. The infrared touch frame 10 is positioned around the screen, and the optical network formed by the infrared touch frame 10 covers the top of the screen. The infrared rays in the optical network perform scanning according to the instructions of the MCU.

[0082] A user can perform a touch operation on the display screen using an object such as a finger or a stylus (also known as a writing pen, smart pen, or touch pen). During a touch operation, as the object gradually approaches the screen, its position moves from above the optical network to blocking some of the infrared light in the optical network. At this point, the intensity of the infrared signal received by infrared receiver 12 corresponding to the blocked infrared light changes, causing the electrical signal output by infrared receiver 12 based on the infrared signal to change. Based on the change in the electrical signal, the blocked infrared light can be determined, and further, whether a touch operation was received and the touch location of the touch operation can be determined. Subsequently, the touch operation can be responded to based on the touch location and other data.

[0083] In one optional method, the MCU can identify data such as the touch location and report it to a processor that controls the display content on the display screen (such as a processor of an electronic device), which then responds. In another optional method, the MCU converts the electrical signal output by the infrared receiver 12 into a digital signal and sends the digital signal to the processor that controls the display content on the display screen, which then identifies data such as the touch location and responds.

[0084] Based on the foregoing, it can be seen that when a touch operation occurs, the more obvious the change in the electrical signal generated by the infrared receiver 12, the more conducive it is to the recognition of the touch operation. Based on this, the infrared touch frame 10 is also provided with an amplifier circuit. The amplifier circuit can be located on the same mainboard as the MCU, or it can be independently provided on a circuit board, and the circuit board can be integrated into a light bar board or provided independently.

[0085] The specific structure of the amplifier circuit can be set according to actual needs. In the related art, a transistor amplifier circuit is used to amplify the electrical signal generated by the infrared receiver 12. For example, Figure 4 is a structural diagram of a transistor amplifier circuit provided in the related art. Figure 4 describes an infrared receiver with two rows and three columns as an example, wherein the infrared receiver is represented by a photosensitive diode (labeled as PD1-PD3, PD7-PD9 in Figure 4). The electrical signal output by each photosensitive diode is first amplified by the corresponding transistor (labeled as Q1-Q3, Q7-Q9 in Figure 4) and then flows into the corresponding receiving bus. Afterwards, the electrical signal in the receiving bus is further amplified by other amplifier circuits to obtain an electrical signal with more obvious characteristics (for example, the characteristics related to infrared light are more obvious). Afterwards, the MCU processes the further amplified electrical signal to identify the touch operation.

[0086] When the receiving bus transmits electrical signals, it's also prone to introducing other noise. For example, in an infrared touch device, if there's a power supply near the receiving bus, the power supply's operation can interfere with the electrical signal transmitted on the receiving bus, introducing other noise into the electrical signal. Furthermore, the longer the receiving bus (i.e., the longer the electrical signal's transmission distance), the more susceptible it is to noise. For example, the longest transmission distance of the electrical signal in Figure 2 is approximately equal to the sum of the long and short sides of the infrared touch frame. This makes it very easy to introduce noise during transmission, resulting in a low signal-to-noise ratio (SNR) for the electrical signal. The SNR for signals with the longest transmission distance typically ranges from 3:1 to 5:1.

[0087] Furthermore, the transistors in each transistor amplifier circuit are independent and discrete. Therefore, the bias voltages of different transistors may vary. The bias voltage of a transistor can be understood as the voltage set when the transistor is in the amplification state. Under the same conditions, when transistors with different bias voltages perform amplification, the voltage values ​​output by each transistor amplifier circuit may also vary. For example, FIG5 is a schematic diagram of the bias voltages of each transistor amplifier circuit connected to the receiving bus 1 in FIG4 . Referring to FIG5 , it shows the voltage values ​​of the electrical signals output by the transistor amplifier circuit including transistor Q1 and the voltage values ​​of the electrical signals output by the transistor amplifier circuit including transistor Q7 in FIG4 . The Q1 circuit bias voltage can be understood as the voltage value of the electrical signal output by the transistor amplifier circuit including transistor Q1 (denoted as Q1 circuit) when no control signal is present. The Q7 circuit bias voltage can be understood as the voltage value of the electrical signal output by the transistor amplifier circuit including transistor Q7 (denoted as Q7 circuit) when no control signal is present. The light-on signal can also be understood as the control signal received by the infrared receiver. The voltage corresponding to the light-on signal can be understood as the voltage corresponding to the electrical signal output by the transistor amplifier circuit when the photodiode at the receiving end receives the control signal. This voltage is the voltage generated by superimposing the infrared signal on the bias voltage of the transistor amplifier circuit (such as the bias voltage of the Q1 circuit and the bias voltage of the Q7 circuit). Photodiodes PD1 and PD7 receive the control signal in sequence and output electrical signals in turn.

[0088] In other words, the voltage of the electrical signal output by the transistor amplifier circuit includes the circuit's bias voltage and the voltage corresponding to the light-on signal. When there is no control signal, the voltage of the electrical signal output by the transistor amplifier circuit is the bias voltage. When there is a control signal, the voltage of the electrical signal output by the transistor amplifier circuit is the voltage corresponding to the light-on signal. In the subsequent identification process, it is necessary to identify the light-on signal in the electrical signal output by the transistor amplifier circuit, and then implement touch detection and positioning based on the light-on signal. In related art, the bias voltage value of the electrical signal output by the transistor amplifier circuit is pre-stored. Then, based on the pre-stored bias voltage and the voltage of the electrical signal actually output by the transistor amplifier circuit, the light-on signal can be identified (i.e., the portion of the electrical signal that differs from the pre-stored bias voltage is the light-on signal). However, because the bias voltages output by different transistor amplifier circuits may be different, the pre-stored bias voltage may not accurately reflect the bias voltage actually output by each transistor amplifier circuit. Therefore, when identifying the light-on signal, the bias voltages actually output by each transistor amplifier circuit will cause interference. For example, referring to FIG5 , the bias voltage of the Q1 circuit is higher than the bias voltage of the Q7 circuit, and the voltage of the light-on signal corresponding to the Q7 circuit is close to the bias voltage of the Q1 circuit. In this case, if the pre-stored bias voltage is closer to the bias voltage of the Q1 circuit, then when the electrical signal output by the Q7 circuit is subsequently identified based on the pre-stored bias voltage, the voltage of the light-on signal corresponding to the Q7 circuit is close to the bias voltage of the Q1 circuit. In other words, the voltage of the light-on signal corresponding to the Q7 circuit is close to the pre-stored bias voltage. Therefore, the light-on signal output by the Q7 circuit is easily identified as the bias voltage, which causes confusion and hinders the identification of the light-on signal. In other words, when identifying the light-on signal, the bias voltage output by the transistor amplifier circuit also becomes a noise signal that generates interference.

[0089] In this way, when the subsequent amplifier circuit amplifies the electrical signal output by the triode amplifier circuit, the signal related to the noise will also be amplified synchronously.

[0090] In related art, when identifying a light-on signal, in order to avoid confusion caused by the bias voltages of different transistor amplifier circuits, the electrical signal output by the transistor amplifier circuit can be filtered when it is amplified to filter out the electrical signal related to the bias voltage while retaining the electrical signal corresponding to the light-on signal. After the filtered electrical signal is received by the MCU, it can be used for subsequent touch detection and positioning. Generally speaking, the bias voltage of the transistor amplifier circuit cannot be removed by a DC blocking capacitor, and it can be considered to be filtered out by a high-pass filter. Among them, high-pass filtering can be understood as allowing frequencies above a certain cutoff frequency to pass through while greatly attenuating lower frequencies. Based on this, the amplifier circuit shown in Figure 6 is proposed. Among them, each receiving bus is connected to an amplifier circuit shown in Figure 6, and is connected to the MCU through each amplifier circuit so that the MCU receives the filtered electrical signal. Among them, Figure 6 shows an amplifier circuit connected to a receiving bus (currently taking receiving bus 1 in Figure 4 as an example). The amplifier circuits connected to other receiving buses have the same structure as the amplifier circuit shown in Figure 6 and are not described in detail here.

[0091] The amplifier circuit shown in Figure 6 is a voltage amplifier circuit implemented using an operational amplifier. It includes an RC high-pass filter circuit (composed of capacitor CS1 and resistor RV1). The RC high-pass filter circuit can filter out interference caused by the bias voltage. However, the RC high-pass filter circuit cannot completely filter out the bias voltage or other noise introduced into the electrical signal. In addition, it may filter out some useful electrical signals (such as the electrical signal corresponding to the light-on signal). In this case, some of the bias voltage and other noise remaining in the electrical signal will be amplified and continue to remain in the electrical signal. In other words, the filtered electrical signal will still contain noise, which is detrimental to the subsequent MCU recognition and processing.

[0092] In related art, the amplifier circuit shown in Figure 6 can be considered a two-stage amplifier circuit. A three-stage amplifier circuit can also be provided after the two-stage amplifier circuit. For example, Figure 7 shows a three-stage amplifier circuit used in related art. The electrical signal output by the two-stage amplifier circuit is further amplified by the three-stage amplifier circuit before being recognized and processed by the MCU. The two-stage amplifier circuit and the three-stage amplifier circuit can be connected via capacitors to achieve isolation and prevent mutual interference.

[0093] It is understandable that there is still noise in the electrical signal output by the secondary amplification circuit. Therefore, after the electrical signal passes through the tertiary amplification circuit, the noise will be further amplified, that is, both useful and useless signals are amplified, which is not conducive to the recognition of touch operations.

[0094] In some scenarios, an integrating operational amplifier circuit can be used as a three-stage amplifier circuit, that is, the three-stage amplifier circuit in Figure 7 is replaced by an integrating operational amplifier circuit. In this case, the integration function can be implemented by the operational amplifier to improve the signal-to-noise ratio of the amplifier circuit (that is, suppress the noise in the electrical signal). For the electrical signal input to the three-stage amplifier circuit (the electrical signal transmitted at AC1 in Figure 7), under the same amplitude, the longer the duration of the electrical signal, the larger the output of the integrating amplifier part, while the voltage amplifier part remains unchanged. For example, Figure 8 shows a schematic diagram comparing the input signal and output signal of the integrating operational amplifier circuit. Referring to Figure 8, after the electrical signals with the same amplitude and different durations (that is, 10mV-5μs input signal and 10mV-10μs input signal) are input, the longer the duration of the electrical signal, the larger the voltage output after the integrated amplification, that is, the larger the output of the integrating amplifier part, and the voltage output of the voltage amplifier remains unchanged, that is, the voltage amplifier part remains unchanged. In this way, although the signal-to-noise ratio of the electrical signal is improved, the longer the integration time of the integral amplifier part is, the greater the interference of the bias voltage in the output electrical signal is, until the electrical signal is saturated, that is, the bias voltage interference still exists in the amplified electrical signal.

[0095] Based on this, an embodiment of the present application provides an infrared signal amplification circuit, which is used to amplify the infrared signal received by the infrared receiver in the infrared touch frame. During the amplification process, it can suppress the influence of the bias voltage of the transistor and the influence of other introduced noise, thereby improving the signal-to-noise ratio of the electrical signal.

[0096] Figure 9 is a structural schematic diagram of an infrared signal amplifying circuit provided by an embodiment of the present application. Referring to Figure 9, the infrared signal amplifying circuit 20 includes: multiple first amplifying units 21 and multiple second amplifying units 22, each first amplifying unit 21 includes an amplifying reference circuit 211 and multiple first-stage amplifying circuits 212.

[0097] Each first-stage amplifier circuit 212 is connected to a corresponding infrared receiver 30, and is used to amplify the first electrical signal output by the infrared receiver 30 to obtain a first amplified electrical signal. The infrared receiver 30 receives an external infrared signal and outputs a corresponding first electrical signal according to a control signal. The control signal is transmitted by a corresponding control bus. Each first amplifier unit 21 corresponds to a control bus, and each control bus transmits the control signal generated by the processor in a cyclic sequence.

[0098] Each amplifying reference circuit 211 is used to generate a second electrical signal according to a control signal. The second electrical signal is a reference signal. The second electrical signal and the first amplified electrical signal output by each first-stage amplifying circuit 212 in the corresponding first amplifying unit 21 form a differential signal.

[0099] Each second amplifying unit 22 is connected to each amplifying reference circuit 211 and to a corresponding first-stage amplifying circuit 212 in each first amplifying unit 21 . The second amplifying unit 22 is configured to amplify the first amplified electrical signal according to the second electrical signal to obtain a second amplified electrical signal.

[0100] Currently, description is made by taking the infrared receiver 30 as an infrared receiver installed in the infrared touch frame and the processor as an MCU installed in the infrared touch frame as an example.

[0101] The electrical signal output by the infrared receiver 30 undergoes two-stage amplification. Currently, the circuit corresponding to the first stage amplification is recorded as a first amplifying unit 21 , and the circuit corresponding to the second stage amplification is recorded as a second amplifying unit 22 .

[0102] In the infrared touch frame scenario, there are multiple first amplifying units 21, and the number of first amplifying units 21 is equal to the number of control buses connected to the MCU. FIG9 takes two first amplifying units 21 as an example to describe their connection relationship.

[0103] The control bus refers to a bus used to transmit control signals, and its specific type is not currently limited. The control signal is generated by the MCU and is used to instruct the infrared receiver 30 to receive infrared signals (i.e., infrared light) in the environment and output a corresponding electrical signal. The control signal can also be considered as a light-on signal that instructs the infrared receiver 30 to turn on the light. The control signal is transmitted in the control bus in the form of an electrical signal. Generally speaking, the number of control buses depends on the number of corresponding interfaces in the MCU and the number of infrared receivers 30 in the infrared touch frame. The embodiment does not limit the number of control buses.

[0104] Illustratively, each first amplifying unit 21 includes multiple first-stage amplifying circuits 212. Currently, the description is based on an example in which each first amplifying unit 21 includes an equal number of first-stage amplifying circuits 212. The number of first-stage amplifying circuits 212 is related to the number of infrared receivers 30, and this is not limited in the present embodiment. FIG. 9 illustrates an example in which each first amplifying unit 21 includes three first-stage amplifying circuits 212.

[0105] Exemplarily, each infrared receiver 30 in the infrared touch frame is connected to a corresponding first-stage amplifier circuit 212 . At this time, a first end of the infrared receiver 30 is connected to the control bus, and a second end of the infrared receiver 30 is connected to a corresponding first-stage amplifier circuit 212 .

[0106] The infrared receivers 30 connected to each primary amplifier circuit 212 in a first amplifier unit 21 are connected to the same control bus, allowing the infrared receivers 30 to connect to the MCU via the corresponding control bus. Furthermore, the infrared receivers 30 connected to different first amplifier units 21 are connected to different control buses. Referring to Figure 9 , primary amplifier circuits 212 in the same row belong to the same first amplifier unit 21 and correspond to a single control bus.

[0107] When the infrared receiver 30 receives the control signal, it collects infrared signals from the external environment (currently, the infrared signals in the environment are infrared light emitted by the infrared transmitter) and outputs a corresponding electrical signal based on the collected infrared signals to the corresponding first-stage amplifier circuit 212. It is understood that when the energy (also understood as the intensity) of the received infrared signals is different, the parameters of the electrical signal are also different, that is, the electrical signal is also considered to be a signal obtained by superimposing the infrared signals.

[0108] Currently, the electrical signal output by infrared receiver 30 is recorded as the first electrical signal, which is an analog electrical signal. After receiving the first electrical signal, first-stage amplifier circuit 212 amplifies the first electrical signal and outputs a corresponding electrical signal. Currently, the electrical signal output by first-stage amplifier circuit 212 is recorded as the first amplified electrical signal, which is an analog electrical signal.

[0109] Exemplarily, the first-stage amplifier circuit 212 is a current amplifier circuit, i.e., configured to amplify the current of the first electrical signal. The first-stage amplifier circuit 212 may be a transistor amplifier circuit, which amplifies the current through a transistor. The specific structure of the first-stage amplifier circuit 212 is not currently limited; it only needs to amplify the current of the first electrical signal.

[0110] In one embodiment, each first amplifying unit 21 further includes an amplifying reference circuit 211. The amplifying reference circuit 211 has a basically identical circuit structure to the first-stage amplifying circuit 212, except that the amplifying reference circuit 211 is not connected to the infrared receiver 30, i.e., the amplifying reference circuit 211 lacks a connection terminal for connecting to the infrared receiver 30.

[0111] The amplifying reference circuit 211 can also amplify current. Both the first-stage amplifying circuit 212 and the amplifying reference circuit 211 are connected to the control bus to receive a control signal. Currently, the electrical signal output by the amplifying reference circuit 211 according to the control signal is recorded as the second electrical signal.

[0112] The amplification reference circuit 211 and the first-stage amplification circuit 212 are located on the same printed circuit board (PCB) and have the same external environment. Since the amplification reference circuit 211 is not connected to the infrared receiver 30, when the control bus transmits the control signal, the electrical signal received by the amplification reference circuit 211 is not superimposed by the infrared signal. At this time, the second electrical signal output by the amplification reference circuit 211 can reflect the amplified electrical signal without the superimposition of the infrared signal. That is, the second electrical signal does not contain any useful signal (signal related to the touch operation). Therefore, the second electrical signal can be considered as a reference signal. By comparing the second electrical signal with the first amplified electrical signal, the noise signal in the first amplified electrical signal can be determined. It can be understood that the different electrical signals between the first amplified electrical signal and the second electrical signal can be considered as electrical signals superimposed by the infrared signal. Currently, the electrical signal superimposed by the infrared signal can be expressed in the form of pulses, that is, the first amplified electrical signal will contain a pulse signal. The second electrical signal is not superimposed by the infrared signal, so the second electrical signal approaches a DC signal (that is, the amplitude is almost unchanged).

[0113] Currently, the amplifying reference circuit 211 and the first-stage amplifying circuit 212 have the same circuit environment. That is, the circuit environment has essentially the same impact on the amplifying reference circuit 211 and the first-stage amplifying circuit 212. Therefore, the noise signals generated by the amplifying reference circuit 211 and the first-stage amplifying circuit 212 under the influence of the circuit environment are essentially the same. In this case, the noise in the second electrical signal and the first amplified electrical signal can form a common-mode signal. A common-mode signal can be understood as a signal with the same current magnitude and direction. However, since the amplifying reference circuit 211 is not superimposed by the infrared signal, while the first-stage amplifying circuit 212 is superimposed by the infrared signal, it can be considered that the second electrical signal contains the noise signal, while the first amplified electrical signal contains the noise signal and the electrical signal superimposed by the infrared signal. In this case, using the second electrical signal as a reference signal allows subsequent processing to filter out electrical signals in the first amplified electrical signal that are unrelated to the infrared signal based on the second electrical signal.

[0114] In one embodiment, the second electrical signal is respectively combined with the first amplified electrical signal output by each first-stage amplification circuit 212 in the first amplification unit 21 where the amplification reference circuit 211 is located to form a differential signal. It is understandable that after subtracting the first amplified electrical signal from the second electrical signal, a positive signal can be obtained, that is, a useful signal (related to the infrared signal). Therefore, the first amplified electrical signal and the second electrical signal can be considered to constitute a differential signal, that is, they can be subtracted to obtain a useful signal. A useful signal refers to an electrical signal superimposed by the infrared signal. It is understandable that based on the above description, the second electrical signal is a reference signal, which can reflect the electrical signal output at the same time when no infrared signal is superimposed, that is, an electrical signal containing only noise. Then, after subtracting the first amplified electrical signal from the second electrical signal at the same time, the electrical signal superimposed by the infrared signal in the first amplified electrical signal (that is, a useful signal) can be obtained. Therefore, each of the first amplified electrical signals output simultaneously can form a differential signal with the second electrical signal, that is, a useful signal is transmitted through the differential signal, and small signals can be easily identified (after subtraction, even signals with very small differences will be retained), thereby making it easier to identify signals related to touch operations in the first amplified electrical signals.

[0115] There are multiple second amplifying units 22 . In one embodiment, the number of the second amplifying units 22 is equal to the number of the first-stage amplifying circuits 212 in the first amplifying unit 21 . FIG. 9 takes three second amplifying units 22 as an example.

[0116] Each second amplifying unit 22 amplifies the first amplified electrical signal output by a first-stage amplifying circuit 212 in each first amplifying unit 21. Different second amplifying units 22 correspond to different first-stage amplifying circuits 212. Referring to FIG9 , each first-stage amplifying circuit 212 and its connected infrared receiver 30 form an array arrangement. The first-stage amplifying circuits 212 in a first amplifying unit 21 can form a row and be connected to the same control bus. The first-stage amplifying circuits 212 in each first amplifying unit 21 can form a column and correspond to the same second amplifying unit 22.

[0117] Each second amplifying unit 22 can receive the first amplified electrical signal and the second electrical signal, and then amplify the first amplified electrical signal based on the second electrical signal. In the embodiment, the electrical signal output by the second amplifying unit 22 is recorded as the second amplified electrical signal, wherein the second amplified electrical signal can be considered as an analog electrical signal obtained by amplifying the useful signal related to the infrared signal in the first amplified electrical signal and suppressing the noise. Specifically, the second amplifying unit 22 can subtract the first amplified electrical signal from the second electrical signal (i.e., subtract the pulse signal from the DC signal) to obtain an electrical signal of a different part from the second electrical signal in the first amplified electrical signal. This part of the electrical signal can be considered as an electrical signal related to the infrared signal, and the part subtracted by the subtraction can be considered as a noise-related part, thereby obtaining a second amplified electrical signal with a higher signal-to-noise ratio. It can be understood that the specific circuit structure of the second amplifying unit 22 is not currently limited, and it only needs to meet the aforementioned functions.

[0118] As described above, by setting a first-stage amplification circuit in the first amplification unit, the electrical signal output by the infrared receiver can be amplified to obtain a first amplified electrical signal. By setting an amplification reference circuit in the first amplification unit, a second electrical signal that can be used as a reference can be obtained while amplifying the electrical signal output by the infrared receiver. The noise signal in the second electrical signal and the noise signal in the first amplified electrical signal are common-mode signals. Therefore, when the first amplified electrical signal is amplified by the second amplification unit, the second electrical signal is referenced to effectively suppress the noise signal while amplifying the electrical signal. That is, the technical problem that the noise in the electrical signal is also amplified synchronously when the electrical signal is amplified is avoided, thereby improving the signal-to-noise ratio of the electrical signal and thereby improving the accuracy of subsequent touch operation recognition.

[0119] In one embodiment of the present application, referring to FIG. 10 , each second amplifying unit 22 includes a voltage follower circuit 221 and a secondary amplifying circuit 222 .

[0120] Each voltage follower circuit 221 is connected to each amplifying reference circuit 211 and is configured to generate a third electrical signal according to the second electrical signal.

[0121] Each secondary amplifier circuit 222 is connected to the corresponding voltage follower circuit 221 and a corresponding primary amplifier circuit 212 in each first amplifier unit 21 , and is configured to amplify the first amplified electrical signal according to the third electrical signal to obtain a second amplified electrical signal.

[0122] In one embodiment, each second amplifying unit 22 includes a voltage follower circuit 221, which is configured to enhance the driving capability of the second electrical signal. The driving capability may also be understood as current driving capability or the ability to drive a load. Generally speaking, the greater the current of the electrical signal, the greater the driving capability.

[0123] Currently, the second electrical signal has only undergone one stage of amplification, and its driving capability is relatively weak compared to the electrical signal amplified by the subsequent amplification circuit. Furthermore, since the reference amplifier circuit and the first-stage amplifier circuit have essentially the same circuit structure, the driving capabilities (current values ​​are not significantly different) of the electrical signals output after amplification by the reference amplifier circuit and the first-stage amplifier circuit are essentially the same, i.e., the driving capabilities of the second electrical signal and the first amplified electrical signal are essentially the same. In this case, when the second electrical signal is used as a reference for each of the first amplified electrical signals, i.e., when the second electrical signal and the first amplified electrical signal are simultaneously input to the next-stage amplifier circuit (currently the second-stage amplifier circuit), the interaction of the currents causes the electrical signals to interact with each other, making the second electrical signal more susceptible to interference from the first amplified electrical signal. It is understandable that because the first amplified electrical signal contains a pulse signal and the second electrical signal is closer to a DC signal, when the two electrical signals are transmitted simultaneously, the first amplified electrical signal is less interfered with by the second electrical signal, while the second electrical signal is more interfered with by the first amplified electrical signal (i.e., the DC signal is more susceptible to fluctuations).

[0124] For example, assume that the first amplification unit 21 includes six first-stage amplification circuits 212, and the electrical signals output by the six first-stage amplification circuits 212 are respectively recorded as first amplified electrical signal 1 to first amplified electrical signal 6. If the infrared signal received by the infrared receiver 30 corresponding to the first amplified electrical signal 1 is blocked, then the first amplified electrical signal 1 does not contain any signal related to the infrared signal. In this case, the first amplified electrical signal 1 can be considered to be a no-signal signal. The infrared signals received by the infrared receiver 30 corresponding to the first amplified electrical signals 2 to 6 are not blocked or not completely blocked. Therefore, the first amplified electrical signals 2 to 6 are output normally, that is, they contain signals related to the infrared signal. Taking the first amplified electrical signal 2 as an example, based on the foregoing, it can be seen that if the second electrical signal and the first amplified electrical signal 2 are simultaneously transmitted to the next-stage amplifier circuit (for example, in the circuit of FIG11 , if the second electrical signal is directly input at RHB and the first amplified electrical signal is directly input at RH1), then during the transmission process, the second electrical signal is susceptible to interference from the first amplified electrical signal 2 and changes, and after the change, it may not be a DC signal. Moreover, since the first amplified electrical signal 1 and the second electrical signal are also transmitted in the circuit, the first amplified electrical signal 1 is a non-signal (also a DC signal), so the interfered second electrical signal will interfere with the first amplified electrical signal 1, that is, the first amplified electrical signal 2 crosstalks with the first amplified electrical signal 1. Based on this, in the embodiment, the driving capability of the second electrical signal is improved by the voltage follower circuit 221 to reduce the interference of the first amplified electrical signal on the second electrical signal, thereby reducing the crosstalk between the first amplified electrical signals.

[0125] Each voltage follower circuit 221 is connected to each amplifying reference circuit 211, meaning that each voltage follower circuit 221 can simultaneously receive the second electrical signal output by the same amplifying reference circuit 211. Alternatively, the output of each amplifying reference circuit 211 can be connected to the same bus, and the input of each voltage follower circuit 221 can also be connected to the same bus, so that the second electrical signal can be transmitted to each voltage follower circuit 221 via the bus.

[0126] The specific structure of the voltage follower circuit 221 is not currently limited, as long as the effect of the voltage follower is achieved. Among them, the voltage follower is a relatively common circuit. The voltage follower can achieve impedance matching, and thus has the function of increasing the load capacity. After the second electrical signal is input into the voltage follower circuit 221, the voltage follower circuit 221 can output an analog electrical signal with a higher load capacity (which can also be understood as a larger current) (compared with the second electrical signal). Currently, the electrical signal output by the voltage follower circuit 221 is recorded as the third electrical signal. Compared with the second electrical signal, the third electrical signal has a higher load capacity and a larger current, and therefore has a higher driving capability. Since the driving capability of the third electrical signal is stronger than that of the second electrical signal, when the third electrical signal and the first amplified electrical signal (with substantially the same driving capability as the second electrical signal) are transmitted simultaneously, the first amplified electrical signal with a smaller driving capability is less likely to interfere with the third electrical signal with a larger driving capability, that is, the third electrical signal is less susceptible to interference, thereby avoiding crosstalk between the first amplified electrical signals and ensuring signal accuracy.

[0127] The voltage follower circuit 221 is further connected to the secondary amplifier circuit 222 in the same second amplifier unit 22, and is configured to output a third electrical signal to the secondary amplifier circuit 222. The secondary amplifier circuit 222 is configured to further amplify the first amplified electrical signal.

[0128] The secondary amplifier circuit 222 is further connected to one primary amplifier circuit 212 in each first amplifier unit 21, and different secondary amplifier circuits 222 are connected to different primary amplifier circuits 212. For example, referring to FIG10 , one secondary amplifier circuit 222 is connected to a column of primary amplifier circuits 212. Alternatively, each primary amplifier circuit 212 in a first amplifier unit 22 is connected to a different bus, and primary amplifier circuits 212 in the same column in different first amplifier units 21 are connected to the same bus. Accordingly, each secondary amplifier circuit 222 is connected to a bus to transmit the first amplified electrical signal via the bus.

[0129] The secondary amplifier circuit 222 is a voltage amplifier circuit, and its specific structure can be configured based on actual needs. In one embodiment, the secondary amplifier circuit 222 has a bandpass filtering function to reduce interference in the electrical signal during voltage amplification. Bandpass filtering refers to allowing waves in a specific frequency band to pass while suppressing waves in other frequency bands. The center frequency of the bandpass filter can be set according to actual conditions. For example, if the frequency of the electrical signal after superimposing the infrared signal is 500 kHz, and the frequency of the electrical signal superimposed by the non-infrared signal (i.e., the noise signal) is 100 kHz, then setting the center frequency of the bandpass filter to 500 kHz can amplify the 500 kHz electrical signal (i.e., the electrical signal after superimposing the infrared signal) while attenuating electrical signals of other frequencies (e.g., the 100 kHz electrical signal). In other words, the infrared signal-related features in the bandpass filtered electrical signal are more prominent. In addition, noise signals can be suppressed, such as the bias voltage and noise introduced by the transistor amplifier circuit. At the same time, interference generated by sunlight or incandescent lamps (light with a non-center frequency) and fluorescent lamps (light with a non-center frequency) can be reduced.

[0130] It can be understood that the secondary amplifier circuit 222 has two input terminals, one for inputting the third electrical signal and the other for inputting the first amplified electrical signal. The secondary amplifier circuit 222 can perform voltage amplification on the first amplified electrical signal, and during voltage amplification, it can filter out signals in the first amplified electrical signal that are not related to the infrared signal based on the third electrical signal. Specifically, after the third electrical signal and the first amplified electrical signal are output to the secondary amplifier circuit together, the secondary amplifier circuit can subtract the first amplified electrical signal from the third electrical signal (i.e., subtract the pulse signal from the DC signal) to obtain an electrical signal in the first amplified electrical signal that is different from the third electrical signal. This electrical signal can be considered to be an electrical signal related to the infrared signal. Moreover, based on the reasonable center frequency set by the bandpass filter, the electrical signal obtained after the subtraction can be bandpass filtered to amplify the electrical signal of the center frequency (related to the infrared signal) and attenuate electrical signals (i.e., noise signals) of other frequencies (not related to the infrared signal). At this time, even if the bias voltage of each first-stage amplifier circuit 212 in the first amplifier circuit 21 (that is, the voltage of the electrical signal output by the circuit when there is no control signal) is different from the bias voltage of the amplifier reference circuit 211, after subtracting the corresponding first amplified electrical signal from the third electrical signal (that is, subtracting the pulse signal from the DC signal), the electrical signal related to the infrared signal can be obtained first, that is, the characteristics related to the infrared signal are retained, and then after band-pass filtering (setting a reasonable center frequency), the part of the first amplified electrical signal that is not related to the infrared signal can be further suppressed, and the part of the first amplified electrical signal that is related to the infrared signal can be amplified.

[0131] Optionally, the secondary amplifier circuit 222 is a bandpass filter circuit, which can obtain a relatively perfect sinusoidal wave signal, that is, the waveform of the second amplified electrical signal is a sine wave, wherein the peak signal point corresponds to the light-on time of the infrared receiver, and the trough signal point corresponds to the light-off time of the infrared receiver. The second amplified electrical signal output by the secondary amplifier circuit 222 can be considered as the electrical signal output by the second amplifier unit 22. The second amplified electrical signal effectively suppresses the bias voltage of the first amplifier circuit, the introduced noise, and the interference generated by other light signals, and amplifies the electrical signal related to the infrared signal. The second amplified electrical signal output by the second amplifier unit 22 can be received by the MCU for subsequent processing to identify the touch operation.

[0132] The above-mentioned second amplification unit can increase the driving capability of the second electrical signal through the voltage follower circuit to obtain a third electrical signal with stronger driving capability, thereby avoiding the second electrical signal being interfered with by the first amplified electrical signal when the second electrical signal is used to process the first amplified electrical signal, and avoiding crosstalk between the first amplified electrical signals. The second amplified electrical signal is amplified by the secondary amplification circuit, and the third electrical signal is referenced during amplification. While achieving amplification, useless noise signals can be effectively removed, thereby improving the accuracy of subsequent touch operation recognition.

[0133] In one embodiment of the present application, FIG11 is a schematic diagram of the structure of a second amplifying unit provided in one embodiment of the present application. The second amplifying unit 22 includes a voltage follower circuit 221 and a secondary amplifying circuit 222 .

[0134] 11 , the voltage follower circuit 221 includes a third resistor R#B and a first operational amplifier UD1D. The non-inverting input of the first operational amplifier UD1D is connected to a first receiving bus RHB and a first end of the third resistor R#B, respectively. The first receiving bus RHB is connected to each amplifying reference circuit 211 to transmit the second electrical signal output by each amplifying reference circuit 211. The inverting input of the first operational amplifier UD1D is connected to the output of the first operational amplifier UD1D. The output of the first operational amplifier UD1D is also connected to a corresponding secondary amplifying circuit 222. The second end of the third resistor R#B is grounded.

[0135] Exemplarily, the voltage follower circuit 221 implements a voltage follower via a first operational amplifier UD1D. Operational amplifiers are commonly used analog integrated circuit components with high amplification and anti-interference capabilities. Operational amplifiers can be designed as derivative circuits for various purposes, such as voltage followers. Typically, when implementing a voltage follower, the inverting input of the operational amplifier is connected to the output of the operational amplifier, the non-inverting input of the operational amplifier receives an external signal, and the output of the operational amplifier outputs a voltage-followed signal. The output signal has the same phase as the input signal, and in this case, the amplification factor of the operational amplifier is equal to 1. Based on this, in this embodiment, the non-inverting input of the first operational amplifier UD1D is connected to all of the amplifying reference circuits 211 to sequentially receive the second electrical signal output by each amplifying reference circuit 211. The inverting input of the first operational amplifier UD1D is connected to the output. The output of the first operational amplifier UD1D is also connected to the secondary amplifying circuit 222 in the same second amplifying unit 22, so that after receiving the second electrical signal, the third electrical signal is output to the secondary amplifying circuit 222 via the output.

[0136] In one embodiment, the non-inverting input terminal of the first operational amplifier UD1D is connected to each amplifier reference circuit 211 via a first receive bus RHB. Each amplifier reference circuit 211 is connected to the first receive bus RHB, and each voltage follower circuit 221 is connected to the first receive bus RHB to transmit the second electrical signal via the first receive bus RHB.

[0137] When the first operational amplifier UD1D implements a voltage follower, external components may be added based on actual circumstances. In this embodiment, a third resistor R#B is provided, with a first end of the third resistor R#B connected to the non-inverting input of the first operational amplifier UD1D and a second end of the third resistor R#B grounded to protect the first operational amplifier UD1D. It is understood that in actual applications, no external components may be provided, and this embodiment is not limited to this.

[0138] 11 , the secondary amplification circuit 222 is a bandpass filter circuit, which includes: a fourth resistor RC1, a fifth resistor RF1, a sixth resistor RD1, a seventh resistor R#1, an eighth resistor RE1, a first capacitor CA1, a second capacitor CF1, a third capacitor CB1, a fourth capacitor CE1, and a second operational amplifier UB1B.

[0139] The first end of the fourth resistor RC1 is connected to the corresponding voltage follower circuit 221. The second end of the fourth resistor RC1 is respectively connected to the first end of the first capacitor CA1 and the first end of the second capacitor CF1. The second end of the first capacitor CA1 is respectively connected to the first end of the fifth resistor RF1 and the inverting input terminal of the second operational amplifier UB1B. The second end of the second capacitor CF1 is respectively connected to the second end of the fifth resistor RF1 and the output terminal of the second operational amplifier UB1B. The first end of the sixth resistor RD1 is respectively connected to the corresponding second receiving bus and the first end of the seventh resistor R#1. Each second receiving bus is respectively connected to a corresponding first-stage amplifier circuit in each first amplification unit. The second end of the sixth resistor RD1 is respectively connected to the first end of the third capacitor CB1 and the first end of the fourth capacitor CE1. The second end of the third capacitor CB1 is respectively connected to the non-inverting input terminal of the second operational amplifier UB1B and the first end of the eighth resistor RE1. The second end of the eighth resistor RE1 and the second end of the fourth capacitor CE1 are connected to the second voltage. The second end of the seventh resistor R#1 is grounded.

[0140] The output terminal of the second operational amplifier UB1B outputs a second amplified electrical signal.

[0141] In the related art, a narrow bandpass filter can be formed based on an operational amplifier. In this case, the operational amplifier is used in reverse mode and receives an external electrical signal through the inverting input terminal. In this article, the bandpass filter formed by the secondary amplification circuit 222 receives two external electrical signals. In this case, referring to Figure 11, the non-inverting input terminal and the inverting input terminal of the second operational amplifier UB1B are both set with reference to the peripheral circuit in the narrow bandpass filter, wherein the peripheral circuit of the non-inverting input terminal is composed of a sixth resistor RD1, an eighth resistor RE1, a third capacitor CB1 and a fourth capacitor CE1, and is used to process the first amplified electrical signal. The peripheral circuit of the inverting input terminal is composed of a fourth resistor RC1, a fifth resistor RF1, a first capacitor CA1, and a second capacitor CF1, and is used to process the third electrical signal. Among them, the application principle of the peripheral circuit is the same as that of the related art and will not be described in detail at present.

[0142] Currently, the non-inverting input terminal of the second operational amplifier UB1B also receives an external signal (i.e., the first amplified electrical signal). Therefore, after the second terminal of the eighth resistor RE1 and the second terminal of the fourth capacitor CE1 are connected, a second voltage is also connected to ensure that the sixth resistor RD1, the eighth resistor RE1, the third capacitor CB1, and the fourth capacitor CE1 can properly process the first amplified electrical signal. The specific value of the second voltage can be set according to actual conditions.

[0143] The seventh resistor R#1 has the same function as the third resistor R#B and is not described in detail here.

[0144] The first end of the sixth resistor RD1 serves as an input end of the secondary amplifier circuit 222 and can receive the first amplified electrical signal output by each connected primary amplifier circuit 212. In this case, the first end of the sixth resistor RD1 needs to be connected to each corresponding primary amplifier circuit 212. In one embodiment, the first end of the sixth resistor RD1 is connected to each primary amplifier circuit 212 via a second receive bus. Each secondary amplifier circuit 222 corresponds to a second receive bus. The secondary amplifier circuit 222 shown in FIG11 corresponds to the second receive bus RH1 and receives the first amplified electrical signal output by each connected primary amplifier circuit 212 via the second receive bus RH1.

[0145] Currently, after the first amplified electrical signal and the third electrical signal are input into the secondary amplifying circuit 222 together, the secondary amplifying circuit subtracts the first amplified electrical signal and the third electrical signal, and then filters the electrical signal obtained after the subtraction based on the set center frequency to output the second amplified electrical signal.

[0146] As described above, implementing the voltage-following function through the first operational amplifier not only simplifies the complexity of the voltage-following circuit but also avoids crosstalk between the first amplified electrical signals. Implementing the bandpass filtering function through the second operational amplifier, by subtracting the first amplified electrical signal from the third electrical signal and then filtering based on a center frequency set relative to the infrared signal, can filter out interference caused by the bias voltage of the triode amplifier circuit in the first amplifying unit and interference caused by introduced noise. It can also filter out interference caused by light of other frequencies. Furthermore, the complexity of the secondary amplification circuit is simplified, making implementation easier.

[0147] In one embodiment of the present application, in addition to the aforementioned circuit structure, the second amplifying unit 22 may also utilize other circuit structures, such as using a subtraction operational amplifier circuit to subtract the first amplified electrical signal from the second electrical signal, thereby using the second electrical signal as a noise reference signal to suppress noise in the first amplified electrical signal. Figure 12 is a schematic diagram of the structure of another second amplifying unit provided in one embodiment of the present application.

[0148] 12 , the second amplifying unit 22 is a subtraction operational amplifier circuit, which includes: a twentieth resistor R#B1, a twenty-first resistor RP1, a twenty-second resistor RK3, a twenty-third resistor RJ2, a twenty-fourth resistor R#2, a twenty-fifth resistor RN1, a twenty-sixth resistor RQ1, a sixth operational amplifier UB1A, a tenth capacitor CP1, an eleventh capacitor CJ2, and a twelfth capacitor CS2.

[0149] Among them, the first end of the 20th resistor R#B1 and the first end of the tenth capacitor CP1 are connected and then connected to the first receiving bus RHB. The first receiving bus RHB is respectively connected to each amplification reference circuit to transmit the second electrical signal output by each amplification reference circuit. The second end of the tenth capacitor CP1 is connected to the first end of the twenty-first resistor RP1 and the first end of the twenty-second resistor RK3. The second end of the twenty-second resistor RK3 is connected to the first end of the eleventh capacitor CJ2, the first end of the twenty-third resistor RJ2, and the inverting input terminal of the sixth operational amplifier UB1A. The second end of the eleventh capacitor CJ2 and the second end of the twenty-third resistor RJ2 are connected and then connected to the output terminal of the sixth operational amplifier UB1A.

[0150] The first end of the twenty-fourth resistor R#2 and the first end of the twelfth capacitor CS2 are connected to the corresponding second receiving bus. Each second receiving bus is respectively connected to a corresponding first-stage amplifier circuit 212 in each first amplifying unit 21. The second end of the twelfth capacitor CS2 is respectively connected to the first end of the twenty-fifth resistor RN1 and the first end of the twenty-sixth resistor RQ1. The second end of the twenty-sixth resistor RQ1 is connected to the non-inverting input terminal of the sixth operational amplifier UB1A.

[0151] The second end of the 20th resistor R#B1 and the second end of the 24th resistor R#2 are both grounded, and the second end of the 21st resistor RP1 and the second end of the 25th resistor RN1 are both connected to the fifth voltage.

[0152] The output terminal of the sixth operational amplifier UB1A outputs a second amplified electrical signal.

[0153] Exemplarily, the first end of the twentieth resistor R#B1 and the first end of the tenth capacitor CP1 are connected together to serve as an input end of the second amplifying unit 22, which can receive the second electrical signal. The first end of the twentieth resistor R#B1 and the first end of the tenth capacitor CP1 are connected together to each amplifying reference circuit 211 via a first receiving bus RHB. The first receiving bus RHB is the same as the first receiving bus RHB shown in FIG. 11 .

[0154] The first end of the twenty-fourth resistor R#2 and the first end of the twelfth capacitor CS2 are connected to each other, serving as another input end of the second amplifying unit 22, capable of receiving the first amplified electrical signal output by each of the first-stage amplifying circuits 212 to which they are connected. In this case, this input end needs to be connected to each corresponding first-stage amplifying circuit 212. In one embodiment, the input end after the first end of the twenty-fourth resistor R#2 and the first end of the twelfth capacitor CS2 are connected is connected to each of the first-stage amplifying circuits 212 via a second receiving bus. The second receiving bus can be the same as the second receiving bus described above in FIG. 11 .

[0155] 12, the subtraction operational amplifier is implemented by the sixth operational amplifier UB1A in the second amplifying unit 22. At present, the voltage of the second amplified electrical signal output by the second amplifying unit 22 is recorded as V out The voltage of the first amplified electrical signal input to the second amplifying unit 22 is recorded as V RH1 The voltage of the second electrical signal input to the second amplifying unit 22 is recorded as V RHB .

[0156] It can be understood that when the operational amplifier is in a linear state, the two input terminals can be considered to be at the same potential. This characteristic can be recorded as the virtual short characteristic of the operational amplifier. At this time, based on the virtual short characteristics of the potential of the operational amplifier's non-inverting input terminal and the potential of the inverting input terminal, the following formula can be obtained:

[0157] Among them, V out is the voltage of the second amplified electrical signal, V RH1 is the voltage of the first amplified electrical signal, V RHB is the voltage of the second electrical signal, RK3 is the resistance value of the twenty-second resistor, and RJ2 is the resistance value of the twenty-third resistor.

[0158] In a circuit structure including an operational amplifier, the resistance value of the 23rd resistor is usually much greater than the resistance value of the 22nd resistor. Generally, the resistance value of the 23rd resistor is 10 to 30 times that of the 22nd resistor. Therefore, the above formula can be converted to: Vout≈RJ2*(V RH1 -V RHB ) (2)

[0159] Based on this formula, the second electrical signal can be subtracted from the first amplified electrical signal, that is, the noise signal represented by the second electrical signal is filtered out from the second amplified electrical signal.

[0160] It should be noted that the second end of the twenty-first resistor RP1 and the second end of the twenty-fifth resistor RN12 are connected to the same voltage (currently recorded as the fifth voltage), and the fifth voltage is the voltage of the low-voltage difference linear regulator (0.8V in Figure 12) to provide an indifferent voltage for the first amplified electrical signal and the second electrical signal.

[0161] The above-mentioned second amplification unit can subtract the noise represented by the second electrical signal from the output second amplified electrical signal through the subtraction operational amplifier circuit, that is, the noise in the first amplified electrical signal is suppressed to obtain a second amplified electrical signal with a higher signal-to-noise ratio. Generally, using the circuit structure shown in Figure 12 and setting reasonable parameters for each component can increase the signal-to-noise ratio of the second amplified electrical signal by 2 to 3 times, which is more conducive to the subsequent recognition of touch operations based on the second amplified electrical signal.

[0162] In one embodiment of the present application, FIG13 is a schematic diagram of the structure of a first amplifying unit provided in one embodiment of the present application. The first amplifying unit 21 includes: an amplifying reference circuit 211 and a plurality of first-stage amplifying circuits 212 .

[0163] Referring to Figure 13, the first-stage amplifier circuit 212 includes: a first resistor and a first transistor, the first end of the first resistor is connected to the corresponding control bus, the second end of the first resistor is respectively connected to the positive electrode of the photosensitive diode in the infrared receiver and the base of the first transistor, the negative electrode of the photosensitive diode in the infrared receiver is connected to the control bus, the collector of the first transistor is connected to the first voltage, and the emitter of the first transistor is connected to the corresponding second receiving bus. Each first-stage amplifier circuit 212 in the first amplifier unit 21 is respectively connected to a different second receiving bus, each second receiving bus is respectively connected to a first-stage amplifier circuit 212 in each first amplifier unit 21, and each second receiving bus is also respectively connected to the corresponding second amplifier unit 22.

[0164] The amplification reference circuit 211 includes: a second resistor and a second transistor, the first end of the second resistor is connected to the corresponding control bus, the second end of the second resistor is connected to the base of the second transistor, the collector of the second transistor is connected to the first voltage, and the emitter of the second transistor is connected to the first receiving bus. Each amplification reference circuit is connected to the first receiving bus, and the first receiving bus is also connected to each second amplification unit 22 respectively.

[0165] Currently, an infrared receiver receives infrared signals through a photodiode as an example, and therefore, a photodiode is used to represent the infrared receiver in Figure 13. In addition, Figure 13 describes an example including two first amplifying units 21, each of which includes three first-stage amplifying circuits 212.

[0166] In FIG13 , both the primary amplifier circuit 212 and the amplifier reference circuit 211 are triode amplifier circuits. The first resistors of each primary amplifier circuit in one first amplifier unit are represented by R1, R2, and R3, respectively, and the first triodes are represented by Q1, Q2, and Q3, respectively. The first resistors of each primary amplifier circuit in another first amplifier unit are represented by R7, R8, and R9, respectively, and the first triodes are represented by Q7, Q8, and Q9, respectively. The second resistors of each amplifier reference circuit in the two first amplifier units are represented by RB1 and RB2, respectively, and the second triodes are represented by QB1 and QB2, respectively. The first and second triodes shown in FIG13 are both NPN triodes.

[0167] In Figure 13 , the first transistor Q1 and the first transistor Q7 are connected to the same second receive bus RH1, the first transistor Q2 and the first transistor Q8 are connected to the same second receive bus RH2, and the first transistor Q3 and the first transistor Q9 are connected to the same second receive bus RH3. The second receive bus is a bus used to transmit the first amplified electrical signal. The number of second receive buses is equal to the number of primary amplifier circuits 212 in the first amplifier unit 21. For example, in Figure 12 , there are three second receive buses. Each second receive bus is connected to a primary amplifier circuit 212 in each first amplifier unit 21, and each primary amplifier circuit 212 in the same first amplifier unit 21 is connected to a different second receive bus.

[0168] In Figure 13 , the second transistor QB1 and the second transistor QB2 are connected to the same first receive bus RHB. The first receive bus is a bus used to transmit the second electrical signal. Each amplifier reference circuit 211 is connected to the same first receive bus, and each voltage follower circuit 221 is connected to the first receive bus RHB, transmitting the same second electrical signal to each voltage follower circuit 221 via the first receive bus RHB.

[0169] It can be understood that the first resistor and the second resistor in the first-stage amplifier circuit and the amplifier reference circuit are the same, the first transistor and the second transistor are the same, and the difference between the first-stage amplifier circuit and the amplifier reference circuit is whether the infrared receiver is connected.

[0170] In FIG13 , the voltages at CS0 and CS1 can be understood as the voltages in the control bus. Generally speaking, the voltages at CS0 and CS1 are equal.

[0171] The first voltage can be set according to actual needs and is used to provide a voltage to the collectors of the first and second transistors, respectively. Currently, the voltage at the base of the first transistor is the bias voltage of the first transistor, and the voltage at the base of the second transistor is the bias voltage of the second transistor. Under the action of the bias voltage, the first and second transistors are in an amplification state. As shown in Figure 13, the voltage of the electrical signal output from the emitter of transistor Q1 to RH1 can be understood as the Q1 circuit bias voltage, that is, the voltage value of the electrical signal output by the triode amplifier circuit (referred to as the Q1 circuit) including transistor Q1 when there is no control signal.

[0172] When the control bus transmits a control signal, the photodiode operates. That is, the photodiode superimposes the voltage of the first electrical signal it outputs based on the intensity of the received infrared signal, thereby causing the voltage at the base of the first transistor to change. At this point, the voltage at the base of the first transistor is the bias voltage superimposed on an additional voltage based on the control signal. This voltage includes the voltage of the first electrical signal output by the photodiode and the voltage when the control signal passes through the first resistor. The voltage at the base of the second transistor in the amplification reference circuit is the bias resistor superimposed on the voltage when the control signal passes through the second resistor. Based on the base voltage change, the electrical signals output by the emitters of the first and second transistors change, causing the collectors to output first amplified electrical signals and second electrical signals. The difference between the first amplified electrical signal and the second electrical signal is that the first amplified electrical signal contains characteristics related to the infrared signal, while the second amplified electrical signal does not.

[0173] It can be understood that the emitter of the first transistor can be considered as the output end of the first-stage amplifier circuit, and the emitter of the second transistor can be considered as the output end of the amplifier reference circuit.

[0174] In the above, the current amplification of the first electrical signal is realized by the first-stage amplifier circuit, and the reference signal unrelated to the infrared signal is generated by the amplification reference circuit, so that in the subsequent processing process, the electrical signal unrelated to the infrared signal in the first amplified electrical signal can be effectively removed based on the reference signal.

[0175] In one embodiment of the present application, to improve the accuracy of touch operation recognition, the infrared signal amplification circuit is further provided with multiple three-stage amplification circuits 23. Figure 14 is a schematic diagram of the structure of another infrared signal amplification circuit provided in one embodiment of the present application. Referring to Figure 14, the infrared signal amplification circuit 20 also includes: multiple three-stage amplification circuits 23, each of which is connected to a second amplification unit 22, for amplifying the second amplified electrical signal to output a third amplified electrical signal.

[0176] The number of three-stage amplification circuits 23 is the same as the number of second amplification units 22. Each three-stage amplification circuit 23 is connected to a second amplification unit 22, and each three-stage amplification circuit 23 is connected to a different second amplification unit 22. The three-stage amplification circuit 23 receives the second amplified electrical signal output by the second amplification unit 22, amplifies the second amplified electrical signal, and outputs an amplified electrical signal. Currently, the electrical signal output by the three-stage amplification circuit 23 is recorded as the third amplified electrical signal. The third amplified electrical signal has more obvious characteristics related to the infrared signal.

[0177] The specific structure of the three-stage amplifier circuit 23 can be set according to actual conditions.

[0178] In one embodiment, the three-stage amplifier circuit 23 is a voltage amplifier circuit that amplifies the voltage in the second amplified electrical signal. Figure 15 is a schematic diagram of the structure of a three-stage amplifier circuit provided in one embodiment of the present application. Referring to Figure 15 , the three-stage amplifier circuit 23 includes: a fifth capacitor CH1, a ninth resistor RK1, a tenth resistor RY1, an eleventh resistor RX1, a twelfth resistor RZ1, and a third operational amplifier UB2C.

[0179] A first end of the fifth capacitor CH1 is connected to the corresponding second amplifying unit 22, a second end of the fifth capacitor CH1 is respectively connected to the first end of the ninth resistor RK1 and the first end of the tenth resistor RY1, a second end of the ninth resistor RK1 and the first end of the eleventh resistor RX1 are connected and then connected to the third voltage, a second end of the eleventh resistor RX1 is respectively connected to the first end of the twelfth resistor RZ1 and the inverting input terminal UB2C of the third operational amplifier, a second end of the twelfth resistor RZ1 is connected to the output terminal of the third operational amplifier UB2C, and a second end of the tenth resistor RY1 is connected to the non-inverting input terminal of the third operational amplifier UB2C; the output terminal of the third operational amplifier UB2C outputs the third amplified electrical signal.

[0180] Exemplarily, the first end of the fifth capacitor CH1 serves as the input of the three-stage amplification circuit 23 and is connected to the corresponding second amplification unit 22. Taking the second amplification unit shown in Figure 10 as an example, the input of the three-stage amplification unit 23 is connected to the corresponding two-stage amplification circuit 222 in the second amplification unit 22. That is, the first end of the fifth capacitor CH1 is connected to the output of the second operational amplifier UB1B to receive the second amplified electrical signal. It will be appreciated that in addition to transmitting the second amplified electrical signal, the fifth capacitor CH1 also prevents mutual interference between the second amplification unit 22 and the three-stage amplification circuit 23 during operation.

[0181] The three-stage amplifier circuit 23 is also connected to a third voltage. The specific value of the third voltage can be set according to actual conditions. In the embodiment, based on the difference between the third voltage and the voltage when the second amplified electrical signal reaches the second end of the fifth capacitor CH1, a resistance difference between the non-inverting input terminal and the inverting input terminal of the third operational amplifier UB2C is achieved, thereby achieving voltage amplification of the second amplified electrical signal.

[0182] In the embodiment, when the second amplifying circuit 22 adopts the circuit structure shown in FIG10 , the second amplified electrical signal is a sinusoidal wave signal, and the peak signal points and the trough signal points of the sinusoidal wave signal correspond to the sampling signal of the processor.

[0183] During the infrared signal processing process, the timing starts when the infrared receiver receives a control signal (i.e., a light-on signal), and stops before the next control signal is received. The timing duration can be considered as one cycle, that is, one control signal is received in one cycle. In the related art, when the MCU processes the corresponding electrical signal (i.e., the electrical signal after multi-stage amplification), the ADC sampling circuit samples once in each cycle, and generally samples once at the peak of the signal (corresponding to the control signal). After that, subsequent processing can be performed based on the sampled signal, such as identifying touch operations. During the non-control signal time (i.e., the time when the infrared receiver turns off the light), the amplifier circuit is discharged so that the MCU does not receive the electrical signal. For example, in the circuit structure shown in Figures 6 and 7, during the non-control signal time, based on the control of the MCU (i.e., the signal transmitted by MCU_R_DD), the switch UC2D is closed to achieve discharge. In this embodiment of the present application, the secondary amplifier circuit 222 is a bandpass filter circuit that can produce a relatively perfect sinusoidal signal. Specifically, the waveform of the second amplified electrical signal is a sinusoidal wave. Within the sinusoidal signal, the peak signal points correspond to the infrared receiver's light-on time, and the trough signal points correspond to the infrared receiver's light-off time. At this point, after the third-stage amplifier circuit 23 shown in FIG15 performs voltage amplification on the second amplified electrical signal, the output third amplified electrical signal also maintains the characteristics of a sinusoidal wave. When the MCU receives the third amplified electrical signal, it can collect both the peak and trough signals, effectively doubling the sampling rate and providing more data to the ADC module, resulting in a higher signal-to-noise ratio.

[0184] For example, FIG16 is a waveform diagram provided by an embodiment of the present application, which shows a waveform diagram of the electrical signal output by the secondary amplifier circuit shown in FIG6 of the related art. Referring to FIG16, there is only one sampling signal point (i.e., sampling point) in one cycle, and the sampling point is located at the end of the peak position. FIG17 is another waveform diagram provided by an embodiment of the present application, which shows a waveform diagram of the second amplified electrical signal output by the secondary amplifier circuit 222 shown in FIG12 of the present application. FIG17 takes the same amplitude of each sine wave as an example. FIG17 corresponds to two sampling signal points (i.e., sampling points) in one cycle, and the two sampling signal points are respectively located at the peak position and the trough position of the sine wave. Compared with FIG16, when the MCU processes the sine wave shown in FIG17, the number of sampled signals is doubled, which provides more data for the ADC module, thereby improving the SNR.

[0185] In one embodiment, the three-stage amplifier circuit 23 can also be an integrating circuit to further remove noise signals from the second amplified electrical signal when amplifying the second amplified electrical signal. Figure 18 is a schematic diagram of the structure of another three-stage amplifier circuit provided in one embodiment of the present application. Referring to Figure 18, the three-stage amplifier circuit 23 includes: a sixth capacitor CH2, a seventh capacitor CL1, an eighth capacitor CZ1, a thirteenth resistor RK2, a fourteenth resistor RY2, a fifteenth resistor RG1, a sixteenth resistor RX2, a first switch UC1C, a second switch UE1C, and a fourth operational amplifier UB1C.

[0186] In particular, a first end of the sixth capacitor CH2 is connected to the corresponding second amplifier circuit 22 to receive the second amplified electrical signal. A second end of the sixth capacitor CH2 is respectively connected to the first end of the thirteenth resistor RK2, the first end of the fourteenth resistor RY2, and the first end of the fifteenth resistor RG1. A second end of the fourteenth resistor RY2 is connected to the non-inverting input terminal of the fourth operational amplifier UB1C. A second end of the fifteenth resistor RG1 is respectively connected to the first end of the seventh capacitor CL1 and the first end of the sixteenth resistor RX2. A second end of the sixteenth resistor RX2 is respectively connected to the inverting input terminal of the fourth operational amplifier UB1C and the first end of the eighth capacitor CZ1. A second end of the eighth capacitor CZ1 is connected to the output terminal of the fourth operational amplifier UB1C. A first switch UC1C is further connected between the first and second ends of the eighth capacitor CZ1. A second switch UE1C is further connected between the first and second ends of the fifteenth resistor RG1. The second end of the thirteenth resistor RK2 and the first end of the seventh capacitor CL1 are respectively grounded.

[0187] The output terminal of the fourth operational amplifier UBIC outputs a third amplified electrical signal.

[0188] Exemplarily, both the first switch UC1C and the second switch UE1C are controlled by the MCU. Specifically, the control terminals R_DD and R_DF of the first and second switches UC1C and UE1C are connected to corresponding interfaces within the MCU, enabling the first and second switches UC1C and UE1C to be closed and opened according to the MCU's control. In this embodiment, when the three-stage amplification circuit 23 is operating, the first and second switches UC1C and UE1C are open to ensure that the MCU receives the third amplified electrical signal. When the three-stage amplification circuit 23 is not operating, the first and second switches UC1C and UE1C are closed for discharge.

[0189] When the three-stage amplifier circuit 23 is operating, i.e., when receiving the second amplified electrical signal, the second amplified electrical signal at AC1 of the three-stage amplifier circuit (corresponding to the second end of the sixth capacitor CH2, the thirteenth resistor RK2, the fourteenth resistor RY2, and the first end of the fifteenth resistor RG1) contains a high-frequency signal and a low-frequency signal. The high-frequency signal corresponds to the light-on signal and is the main component of the second amplified electrical signal. The low-frequency signal corresponds to the bias signal and / or noise signal of the triode amplifier circuit that has not been completely filtered out. Most of the low-frequency signal has been filtered out in the second amplifier circuit 22 (the second-stage amplifier circuit 222 shown in FIG. 11). A small portion may remain unfiltered, but this residual signal has little impact on subsequent touch recognition and positioning. However, in actual applications, the high-frequency signal may also be mixed with other signals. For example, the frequency of some noise signals is higher than the frequency of the electrical signal superimposed with the infrared signal under the light-on signal. In this case, these high-frequency noise signals may still remain in the second amplified electrical signal after being processed by the aforementioned two-stage circuit. In this case, the high-frequency noise signals can be filtered out by the three-stage amplifier circuit 23. Currently, in the three-stage amplifier circuit 23, the fifteenth resistor RG1 and the seventh capacitor CL1 form an RC low-pass circuit, allowing the low-frequency signal in the second amplified electrical signal to flow to the second end of the fifteenth resistor RG1 (corresponding to V1 in FIG. 18 ). At this time, the currents of the electrical signal passing through the sixteenth resistor RX2 and the electrical signal passing through the eighth capacitor CZ1 are equal, and the following formula can be obtained:

[0190] Among them, V CZ1 represents the resistance value at the second end of the eighth capacitor CZ1, V1 represents the resistance value at the first end of the sixteenth resistor RX2, RX2 represents the resistance value of the sixteenth resistor RX2, CZ1 represents the capacitance value of the eighth capacitor CZ1, V AD1 represents the resistance value at the second end of the sixteenth resistor RX2 (which can also be understood as the resistance value of the output end of the third operational amplifier), and dt represents the time integral.

[0191] After transforming formula (3), the following formula can be obtained:

[0192] Where ∆V is V CZ1 -V1 value, which can be understood as the voltage value of the high frequency part of the second amplified electrical signal at AC1. In formula (4), since the value of RX2*CZ1 is very small (the value of RX2 is in the hundred ohm level, and the value of CZ1 is in the pf level), and V CZ1 can be ignored, so based on formula (4), the voltage value of the output terminal of the third operational amplifier (i.e., V AD1) is the temporal integral of the high-frequency signal in the second amplified electrical signal. This suppresses the higher-frequency signals within the high-frequency portion of the second amplified electrical signal. The higher-frequency signals can be considered as signals unrelated to the infrared signal. It can be understood that the integration circuit has the function of suppressing high-frequency signals. When processing the high-frequency signal, the higher-frequency signals contained therein can be considered the high-frequency signals to be suppressed, while the remaining high-frequency signals can be considered the low-frequency signals to be retained (i.e., amplified). The terms "high-frequency signals to be suppressed" and "low-frequency signals to be retained" are relative terms, specifically referring to the high-frequency signals within the second amplified electrical signal. When the integration circuit processes the high-frequency signal, it can be considered to present a low impedance to the higher-frequency signals. In this case, the amplification factor of the higher-frequency signals is less than 1, indicating that the higher-frequency signals are suppressed. For the signals within the high-frequency signal related to the infrared signal (which have a lower frequency than the higher-frequency signals), the integration circuit presents a high impedance to these signals. In this case, the amplification factor of these signals is greater than 1, achieving the purpose of amplifying these signals (i.e., the signals related to the infrared signal).

[0193] As described above, high-pass filtering is performed by the integration circuit, which can further reduce the higher-frequency useless signals in the second amplified electrical signal, while amplifying the signal related to the infrared signal in the second amplified electrical signal, thereby ensuring that the quality of the obtained third amplified electrical signal is higher and touch recognition and positioning can be performed more accurately.

[0194] In one embodiment of the present application, in order to further ensure the accuracy of the subsequent MCU in identifying touch operations, an additional first-stage amplifier circuit can be added to the second amplifier circuit 22 and the third-stage amplifier circuit 23. Currently, the additional first-stage amplifier circuit is recorded as a fourth-stage amplifier circuit 24. Figure 19 is a structural schematic diagram of another infrared signal amplification circuit provided by an embodiment of the present application. Referring to Figure 19, the infrared signal amplification circuit also includes: a plurality of four-stage amplifier circuits 24, each three-stage amplifier circuit 23 is connected to the corresponding second amplifier circuit 22 through the corresponding four-stage amplifier circuit 24, and the four-stage amplifier circuit 24 is used to amplify the second amplified electrical signal to obtain a fourth amplified electrical signal, and send the fourth amplified electrical signal to the three-stage amplifier circuit 23, so that the three-stage amplifier circuit 23 amplifies the fourth amplified electrical signal to obtain a third amplified electrical signal.

[0195] Exemplarily, the number of four-stage amplifying circuits 24 is equal to the number of three-stage amplifying circuits 23 and second amplifying circuits 22, each four-stage amplifying circuit corresponds to a three-stage amplifying circuit, and each three-stage amplifying circuit 23 and the corresponding second amplifying circuit 22 can be connected through the corresponding four-stage amplifying circuit 24.

[0196] After receiving the second amplified electrical signal output by the second amplifying circuit 22, the fourth-stage amplifying circuit 24 amplifies the second amplified electrical signal and outputs the amplified electrical signal. Currently, the amplified electrical signal is recorded as the fourth amplified electrical signal. Correspondingly, the third-stage amplifying circuit 23 receives the fourth amplified electrical signal and obtains the third amplified electrical signal based on the fourth amplified electrical signal.

[0197] The four-stage amplifier circuit 24 is a voltage amplifier circuit, and its specific structure can be configured according to actual needs. For example, Figure 20 is a schematic diagram of the structure of a four-stage amplifier circuit provided in one embodiment of the present application. Referring to Figure 20, the four-stage amplifier circuit 24 includes a seventeenth resistor RJ1, an eighteenth resistor RI1, a nineteenth resistor RM1, a ninth capacitor CM1, and a fifth operational amplifier UB2B.

[0198] Among them, the first end of the seventeenth resistor RJ1 is connected to the corresponding second amplifier circuit 22, the second end of the seventeenth resistor RJ1 is connected to the non-inverting input terminal of the fifth operational amplifier UB2B, the first end of the eighteenth resistor RI1 is connected to the fourth voltage, the second end of the eighteenth resistor RI1 is respectively connected to the inverting input terminal of the fifth operational amplifier UB2B, the first end of the nineteenth resistor RM1 and the first end of the ninth capacitor CM1, and the output end of the fifth operational amplifier UB2B is respectively connected to the second end of the nineteenth resistor RM1, the second end of the ninth capacitor CM1 and the corresponding three-stage amplifier circuit 23.

[0199] The output terminal of the fifth operational amplifier UB2B outputs a fourth amplified electrical signal.

[0200] It is understood that the specific value of the fourth resistor is set based on actual conditions. Optionally, the fourth voltage and the second voltage can be equal, and for example, both can be set to 1.65V based on actual needs. After the fourth voltage is set, the four-stage amplifier circuit 24 amplifies the voltage of the second amplified electrical signal input to the same-direction receiving end based on the resistance difference between the same-direction receiving end and the opposite-direction receiving end of the fifth operational amplifier UB2B.

[0201] As described above, by setting up a four-stage amplification circuit, when the intensity of the infrared signal received by the infrared receiver is insufficient (for example, the distance between the infrared receiver and the infrared transmitter is far, resulting in insufficient intensity of the infrared signal), the second amplified electrical signal can be voltage amplified to enhance the characteristics related to the infrared signal in the electrical signal.

[0202] It can be understood that each of the operational amplifiers mentioned above also has an interface for connecting to a power supply and an interface for connecting to a ground, which can be connected to a power supply and a ground respectively.

[0203] One embodiment of the present application further provides an infrared touch device, comprising: a mainboard; a plurality of light strips, each of which is provided with at least one infrared receiver and at least one infrared transmitter; and a processor and the aforementioned infrared signal amplification circuit. The processor is configured to control the infrared transmitter to emit infrared signals and the infrared receiver to receive external infrared signals. When the infrared receiver receives the external infrared signal, it outputs a corresponding first electrical signal to the infrared signal amplification circuit; the infrared signal amplification circuit is configured to amplify the first electrical signal.

[0204] For example, the light bar board installed in the infrared touch device can refer to the light bar board in the related art. Currently, a light bar board can be installed with multiple infrared transmitters, multiple infrared receivers, or a mixture of infrared transmitters and infrared receivers. The embodiment does not limit this.

[0205] The motherboard can refer to the motherboard in the related art. Currently, taking the installation of the processor and the infrared signal amplifying circuit on the motherboard as an example, in actual application, the circuit board where the infrared signal amplifying circuit is located can be independent of the motherboard.

[0206] Optionally, the light bar board and the main board where the corresponding processor is located can form an infrared touch frame.

[0207] It is understood that the infrared touch device can be an electronic device with a display screen and capable of infrared touch, such as an interactive smart tablet, a mobile phone, a television, a tablet computer, an electronic billboard, etc. The infrared touch device can also be an infrared touch frame.

[0208] When the infrared touch device is an electronic device, its display screen may be a liquid crystal display (LCD), an LED display (LED display), an organic light emitting diode (OLED) display, or a flexible light emitting diode (FLED) display. The display screen may be a flat screen or a curved screen, which is not limited in the embodiment.

[0209] The electronic device may be equipped with one or more display screens. When there are multiple display screens, the layout of the multiple display screens is currently not limited. For example, the multiple display screens may be arranged horizontally on the left and right sides, or on the front and back of the electronic device. Furthermore, when the electronic device is a mobile phone, the display screen may also be a foldable display screen.

[0210] Currently, the display screen has a touch function and can also be recorded as a touch display screen, touch screen, etc. Currently, the display screen realizes the touch function through infrared touch. In this case, the light bar is set around the edge of the display screen, and the infrared transmitter and infrared receiver on the light bar generate a light network covering the top of the display screen.

[0211] During operation of the infrared touch device, the processor controls the infrared transmitter to emit infrared signals and the infrared receiver to receive external infrared signals. Upon receiving an external infrared signal under the control of the processor, the infrared receiver outputs a corresponding first electrical signal to the infrared signal amplification circuit. The infrared signal amplification circuit then amplifies the first electrical signal.

[0212] It should be noted that the technical details not disclosed in the infrared touch device can refer to the relevant description of the aforementioned infrared signal amplification circuit, which has corresponding functions and beneficial effects.

[0213] It should be noted that the reference to infrared receivers in an array configuration in this disclosure does not imply that the infrared receivers are actually arranged in an array, but rather that their wiring can be simplified to represent an array configuration. The parameters of the various circuit components designed within the infrared signal amplification circuit can be selected based on practical needs and are not limited in this embodiment. Furthermore, the reference numbers associated with each component are merely used to identify the component and do not define it; components with the same reference number may represent different components in different circuits.

[0214] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0215] Note that the above are only preferred embodiments of the present application and the technical principles employed. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present application. The scope of the present application is determined by the scope of the appended claims.

Claims

1. An infrared signal amplification circuit, wherein: include: A plurality of first amplifying units and a plurality of second amplifying units, each of the first amplifying units comprising an amplifying reference circuit and a plurality of first-stage amplifying circuits; Each of the first-stage amplifier circuits is connected to a corresponding infrared receiver, and is used to amplify a first electrical signal output by the infrared receiver to obtain a first amplified electrical signal. The infrared receiver receives an external infrared signal and outputs a corresponding first electrical signal according to a control signal. The control signal is transmitted by a corresponding control bus. Each of the first amplifier units corresponds to a control bus, and each of the control buses sequentially and cyclically transmits the control signal generated by the processor. Each of the amplifying reference circuits is used to generate a second electrical signal according to the control signal, the second electrical signal being a reference signal, and the second electrical signal and the first amplified electrical signal output by each first-stage amplifying circuit in the corresponding first amplifying unit respectively form a differential signal; Each of the second amplifying units is connected to each of the amplifying reference circuits and to a corresponding first-stage amplifying circuit in each of the first amplifying units. The second amplifying unit is used to amplify the first amplified electrical signal according to the second electrical signal to obtain a second amplified electrical signal.

2. The infrared signal amplifying circuit according to claim 1, wherein: Each of the second amplifying units includes a voltage follower circuit and a secondary amplifying circuit; Each of the voltage follower circuits is connected to each of the amplifying reference circuits, and is used to generate a third electrical signal according to the second electrical signal; Each of the two-stage amplifier circuits is connected to a corresponding voltage follower circuit and a corresponding one-stage amplifier circuit in each of the first amplifier units, and is used to amplify the first amplified electrical signal according to the third electrical signal to obtain a second amplified electrical signal.

3. The infrared signal amplifying circuit according to claim 2, wherein: The voltage follower circuit includes: a third resistor and a first operational amplifier, The non-inverting input terminal of the first operational amplifier is respectively connected to the first receiving bus and the first end of the third resistor, the first receiving bus is respectively connected to each amplifying reference circuit to transmit the second electrical signal output by each amplifying reference circuit, the inverting input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, the output terminal of the first operational amplifier is also connected to the corresponding secondary amplifying circuit, and the second end of the third resistor is grounded.

4. The infrared signal amplifying circuit according to claim 2, wherein: The secondary amplifier circuit is a bandpass filter circuit, which includes: a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and a second operational amplifier. The first end of the fourth resistor is connected to the corresponding voltage follower circuit, the second end of the fourth resistor is respectively connected to the first end of the first capacitor and the first end of the second capacitor, the second end of the first capacitor is respectively connected to the first end of the fifth resistor and the inverting input end of the second operational amplifier, the second end of the second capacitor is respectively connected to the second end of the fifth resistor and the output end of the second operational amplifier, the first end of the sixth resistor is respectively connected to the corresponding second receiving bus and the first end of the seventh resistor, each of the second receiving buses is respectively connected to a corresponding first-level amplifier circuit in each of the first amplification units, the second end of the sixth resistor is respectively connected to the first end of the third capacitor and the first end of the fourth capacitor, the second end of the third capacitor is respectively connected to the non-inverting input end of the second operational amplifier and the first end of the eighth resistor, the second end of the eighth resistor and the second end of the fourth capacitor are connected and then connected to the second voltage, and the second end of the seventh resistor is grounded; The output terminal of the second operational amplifier outputs the second amplified electrical signal.

5. The infrared signal amplifying circuit according to claim 1, wherein: The second amplifying unit is a subtraction operational amplifier circuit, and the subtraction operational amplifier circuit includes: a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a sixth operational amplifier, a tenth capacitor, an eleventh capacitor, and a twelfth capacitor; The first end of the 20th resistor and the first end of the 10th capacitor are connected and then connected to a first receiving bus, the first receiving bus is respectively connected to each amplifying reference circuit to transmit the second electrical signal output by each amplifying reference circuit, the second end of the 10th capacitor is connected to the first end of the 21st resistor and the first end of the 22nd resistor, the second end of the 22nd resistor is connected to the first end of the 11th capacitor, the first end of the 23rd resistor and the inverting input end of the sixth operational amplifier, the second end of the 11th capacitor and the second end of the 23rd resistor are connected and then connected to the output end of the sixth operational amplifier; The first end of the twenty-fourth resistor and the first end of the twelfth capacitor are connected to the corresponding second receiving bus, each of the second receiving buses is respectively connected to a corresponding first-stage amplifier circuit in each of the first amplifying units, the second end of the twelfth capacitor is respectively connected to the first end of the twenty-fifth resistor and the first end of the twenty-sixth resistor, and the second end of the twenty-sixth resistor is connected to the non-inverting input terminal of the sixth operational amplifier; The second end of the 20th resistor and the second end of the 24th resistor are both grounded, and the second end of the 21st resistor and the second end of the 25th resistor are both connected to a fifth voltage; The output terminal of the sixth operational amplifier outputs the second amplified electrical signal.

6. The infrared signal amplifying circuit according to any one of claims 1 to 5, wherein: Also includes: multiple three-stage amplifier circuits, Each of the three-stage amplification circuits is respectively connected to a second amplification unit for amplifying the second amplified electrical signal to obtain a third amplified electrical signal.

7. The infrared signal amplifying circuit according to claim 6, wherein: The three-stage amplification circuit includes: a fifth capacitor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor and a third operational amplifier; The first end of the fifth capacitor is connected to the corresponding second amplifying unit, the second end of the fifth capacitor is respectively connected to the first end of the ninth resistor and the first end of the tenth resistor, the second end of the ninth resistor is connected to the first end of the eleventh resistor and then connected to a third voltage, the second end of the eleventh resistor is respectively connected to the first end of the twelfth resistor and the inverting input end of the third operational amplifier, the second end of the twelfth resistor is connected to the output end of the third operational amplifier, and the second end of the tenth resistor is connected to the non-inverting input end of the third operational amplifier; The output terminal of the third operational amplifier outputs the third amplified electrical signal.

8. The infrared signal amplifying circuit according to claim 4, wherein: The second amplified electrical signal is a sine wave signal, and the peak signal points and the trough signal points of the sine wave signal correspond to the sampling signal of the processor.

9. The infrared signal amplifying circuit according to claim 6, wherein: The three-stage amplification circuit includes: a sixth capacitor, a seventh capacitor, an eighth capacitor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a first switch, a second switch and a fourth operational amplifier. The first end of the sixth capacitor is connected to the corresponding second amplifying unit, the second end of the sixth capacitor is respectively connected to the first end of the thirteenth resistor, the first end of the fourteenth resistor and the first end of the fifteenth resistor, the second end of the fourteenth resistor is connected to the non-inverting input terminal of the fourth operational amplifier, the second end of the fifteenth resistor is respectively connected to the first end of the seventh capacitor and the first end of the sixteenth resistor, the second end of the sixteenth resistor is respectively connected to the inverting input terminal of the fourth operational amplifier and the first end of the eighth capacitor, the second end of the eighth capacitor is connected to the output terminal of the fourth operational amplifier, a first switch is further connected between the first end and the second end of the eighth capacitor, a second switch is further connected between the first end and the second end of the fifteenth resistor, the second end of the thirteenth resistor and the first end of the seventh capacitor are respectively connected to the first end of the seventh capacitor. One end is grounded respectively; The output terminal of the fourth operational amplifier outputs the third amplified electrical signal.

10. The infrared signal amplifying circuit according to claim 9, wherein: Also includes: multiple four-stage amplifier circuits, Each of the three-stage amplifier circuits is connected to the corresponding second amplifier unit through a corresponding four-stage amplifier circuit, and the four-stage amplifier circuit is used to amplify the second amplified electrical signal to obtain a fourth amplified electrical signal, and send the fourth amplified electrical signal to the three-stage amplifier circuit, so that the three-stage amplifier circuit amplifies the fourth amplified electrical signal to obtain the third amplified electrical signal.

11. The infrared signal amplifying circuit according to claim 10, wherein: The four-stage amplification circuit includes: a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a ninth capacitor and a fifth operational amplifier. The first end of the seventeenth resistor is connected to the corresponding second amplifying unit, the second end of the seventeenth resistor is connected to the non-inverting input end of the fifth operational amplifier, the first end of the eighteenth resistor is connected to the fourth voltage, the second end of the eighteenth resistor is respectively connected to the inverting input end of the fifth operational amplifier, the first end of the nineteenth resistor and the first end of the ninth capacitor, and the output end of the fifth operational amplifier is respectively connected to the second end of the nineteenth resistor, the second end of the ninth capacitor and the corresponding three-stage amplifying circuit; The output terminal of the fifth operational amplifier outputs the fourth amplified electrical signal.

12. The infrared signal amplifying circuit according to claim 1, wherein: The first-stage amplification circuit includes: a first resistor and a first transistor, The first end of the first resistor is connected to the corresponding control bus, the second end of the first resistor is respectively connected to the positive electrode of the photosensitive diode in the infrared receiver and the base of the first transistor, the negative electrode of the photosensitive diode in the infrared receiver is connected to the control bus, the collector of the first transistor is connected to the first voltage, the emitter of the first transistor is connected to the corresponding second receiving bus, each first-level amplifier circuit in the first amplifier unit is respectively connected to a different second receiving bus, each second receiving bus is connected to a first-level amplifier circuit in each first amplifier unit, and each second receiving bus is also respectively connected to the corresponding second amplifier unit; The amplification reference circuit comprises: a second resistor and a second triode, The first end of the second resistor is connected to the corresponding control bus, the second end of the second resistor is connected to the base of the second transistor, the collector of the second transistor is connected to the first voltage, the emitter of the second transistor is connected to the first receiving bus, each of the amplification reference circuits is connected to the first receiving bus, and the first receiving bus is also connected to each second amplification unit respectively.

13. An infrared touch device, wherein: include: A main board and a plurality of light strips, wherein the light strips are provided with at least one infrared receiver and at least one infrared transmitter, and the main board is provided with a processor and an infrared signal amplifying circuit as claimed in any one of claims 1 to 12, The processor is used to control the infrared transmitter to transmit infrared signals externally, and to control the infrared receiver to receive external infrared signals, and the infrared receiver outputs a corresponding first electrical signal to the infrared signal amplifying circuit when receiving external infrared signals; The infrared signal amplifying circuit is used to amplify the first electrical signal.

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