Intelligent interactive tablet

Abstract

The present invention relates to the field of tablets, and disclosed is an intelligent interactive tablet. The intelligent interactive tablet comprises multiple piezoelectric sensors arranged in parallel, and multiple detection circuit modules corresponding one-to-one with the multiple piezoelectric sensors. Each detection circuit module comprises a signal transmitting circuit, a piezoelectric sensor channel circuit, an operation circuit, a first voltage reference end, and a processor. The piezoelectric sensor channel circuit comprises a signal isolation circuit, a first access end, and a second access end. The signal isolation circuit is electrically connected to an output end of the signal transmitting circuit. The second access end is electrically connected to the first voltage reference end. The operation circuit is separately electrically connected to the signal isolation circuit, the first voltage reference end, and the processor, and outputs a conditioning voltage signal to the processor, so that the processor determines the state of the piezoelectric sensor on the basis of the conditioning voltage signal. Thus, poor electrical connections of the piezoelectric sensors are intercepted in the early stages of a process, and the trouble of subsequent disassembly is avoided.

Description

A smart interactive tablet Technical Field

[0001] The present invention relates to the field of tablet computers, and in particular to an intelligent interactive tablet computer. Background Art

[0002] In some large-sized smart interactive tablets, piezoelectric sensors are generally used to detect user touch gestures on the touch screen to perform different interactive functions. Piezoelectric sensors have become one of the necessary components of smart interactive tablets.

[0003] Piezoelectric sensors are typically glued and installed underneath the inner glass surface of a smart interactive tablet's touchscreen. During the touchscreen assembly process, poor electrical connections may occur in the piezoelectric sensors. A smart interactive tablet equipped with a piezoelectric sensor with potentially poor electrical connections will experience a misalignment in the touchscreen's recognition rate, reducing product quality and impacting user experience. Currently, poor electrical connections in piezoelectric sensors can only be detected after the entire smart interactive tablet is installed. When such poor electrical connections are detected, the device must be disassembled to remove the piezoelectric sensor, which is installed underneath the innermost glass surface of the touchscreen. This cumbersome disassembly process impacts production efficiency.

[0004] Summary of the Invention

[0005] The embodiment of the present application aims to provide a smart interactive tablet, which can solve the problem of existing smart interactive tablets that when the piezoelectric sensor is found to have poor electrical connection after assembly, the piezoelectric sensor installed under the inner surface glass of the touch screen needs to be disassembled, which is cumbersome and affects production efficiency.

[0006] To solve the above technical problems, the first embodiment of the present invention provides a smart interactive tablet, comprising:

[0007] Multiple piezoelectric sensors arranged in parallel, the multiple piezoelectric sensors being installed below the glass on the inner surface of the smart interactive flat-panel touch screen; multiple detection circuit modules corresponding one-to-one to the multiple piezoelectric sensors;

[0008] Wherein, the detection circuit module includes: a signal transmission circuit, a piezoelectric sensor channel circuit, an operation circuit, a first voltage reference terminal and a processor;

[0009] The piezoelectric sensor channel circuit includes a signal isolation circuit, a first access terminal, and a second access terminal; the first access terminal and the second access terminal are used to connect to the piezoelectric sensor; the signal isolation circuit is electrically connected to the output terminal of the signal transmission circuit, and is used to receive the signal transmitted by the signal transmission circuit; the first access terminal is electrically connected to the signal isolation circuit; and the second access terminal is electrically connected to the first voltage reference terminal;

[0010] The operation circuit is electrically connected to the signal isolation circuit, the first voltage reference terminal and the processor respectively, and is used to output a conditioned voltage signal to the processor;

[0011] The processor is used to determine the state of the piezoelectric sensor based on the conditioned voltage signal; specifically: when the conditioned voltage signal is higher than a preset threshold, the piezoelectric sensor is determined to be in a normal state; when the conditioned voltage signal is lower than the preset threshold, the piezoelectric sensor is determined to be in an abnormal state, and when the number of the piezoelectric sensors in the abnormal state is lower than a set value, the processor shields the signal transmitted by the piezoelectric sensor in the abnormal state.

[0012] In one embodiment, the signal transmitting circuit includes at least one GPIO port, and the GPIO port is electrically connected to the signal isolation circuit of the piezoelectric sensor channel circuit, and is used to stimulate a short square wave pulse signal to the signal isolation circuit.

[0013] In one embodiment, the signal isolation circuit includes a transistor and a third resistor, the base of the transistor is electrically connected to the GPIO port, the collector of the transistor is electrically connected to the second reference voltage terminal through the third resistor, and the emitter of the transistor is the first access terminal.

[0014] In one embodiment, the signal isolation circuit includes a MOS transistor and a fourth resistor, the gate of the MOS transistor is electrically connected to the GPIO port, the drain of the MOS transistor is electrically connected to the second reference voltage terminal through the fourth resistor, and the source of the MOS transistor is the first access terminal.

[0015] In one embodiment, the operational circuit is an operational amplifier circuit, and the operational circuit includes a current limiting circuit and a signal conditioning circuit, wherein: the current limiting circuit is electrically connected to the output end of the signal isolation circuit; the signal conditioning circuit is electrically connected to the current limiting circuit, the first voltage reference end and the processor, respectively, for outputting a conditioned voltage signal to the processor.

[0016] In one embodiment, the current limiting circuit includes a first resistor, and the first resistor is electrically connected to the output end of the signal isolation circuit.

[0017] In one embodiment, the signal conditioning circuit includes an operational amplifier and a feedback circuit; the positive input terminal of the operational amplifier is electrically connected to the first voltage reference terminal, and the negative input terminal of the operational amplifier is electrically connected to the current limiting circuit; the output terminal of the operational amplifier is electrically connected to the negative input terminal of the operational amplifier through the feedback circuit, and the output terminal of the operational amplifier is used to output a conditioned voltage signal.

[0018] In one embodiment, the feedback circuit includes a second resistor and a second capacitor, the second resistor and the second capacitor are connected in parallel, and the two connection ends of the second resistor and the second capacitor after being connected in parallel are electrically connected to the negative input terminal and the output terminal of the operational amplifier respectively.

[0019] In one embodiment, the reference voltage of the second reference voltage terminal is greater than the reference voltage of the first reference voltage terminal.

[0020] Accordingly, the second embodiment of the present invention further provides a smart interactive tablet, comprising: a plurality of piezoelectric sensors, the plurality of piezoelectric sensors being mounted below the glass on the inner surface of the touch screen of the smart interactive tablet; a plurality of detection circuit modules corresponding one-to-one to the plurality of piezoelectric sensors;

[0021] Wherein, the detection circuit module includes: a signal transmission circuit, a piezoelectric sensor channel circuit, an operation circuit, a first voltage reference terminal and a processor;

[0022] The signal transmitting circuit includes a plurality of pairs of short square wave pulse differential signals, each pair of short square wave pulse differential signals includes a first differential signal output terminal and a second differential signal output terminal;

[0023] Each of the piezoelectric sensor channel circuits includes a first access terminal and a second access terminal; the first access terminal and the second access terminal are used to connect to the piezoelectric sensor; the first access terminal and the second access terminal are respectively electrically connected to a first differential signal output terminal and a second differential signal output terminal of a pair of differential signals of the signal transmitting circuit;

[0024] The operation circuit is electrically connected to each piezoelectric sensor channel circuit, the first voltage reference terminal and the processor, and is used to output a conditioned voltage signal to the processor;

[0025] The processor is used to determine the state of the piezoelectric sensor based on the conditioned voltage signal; specifically: when the conditioned voltage signal is higher than a preset threshold, the piezoelectric sensor is determined to be in a normal state; when the conditioned voltage signal is lower than the preset threshold, the piezoelectric sensor is determined to be in an abnormal state; when the number of the piezoelectric sensors in the abnormal state is lower than a set value, the processor shields the signals transmitted by the piezoelectric sensors in the abnormal state.

[0026] In one embodiment, the operational circuit is an operational amplifier circuit, and the operational circuit includes a current limiting circuit and a signal conditioning circuit, wherein: the current limiting circuit is electrically connected to the output end of the signal isolation circuit; the signal conditioning circuit is electrically connected to the current limiting circuit, the first voltage reference end and the processor, respectively, for outputting a conditioned voltage signal to the processor.

[0027] In one embodiment, the current limiting circuit includes a first resistor, and the first resistor is electrically connected to the output end of the signal isolation circuit.

[0028] In one embodiment, the signal conditioning circuit includes an operational amplifier and a feedback circuit; the positive input terminal of the operational amplifier is electrically connected to the first voltage reference terminal, and the negative input terminal of the operational amplifier is electrically connected to the current limiting circuit; the output terminal of the operational amplifier is electrically connected to the negative input terminal of the operational amplifier through the feedback circuit, and the output terminal of the operational amplifier is used to output a conditioned voltage signal.

[0029] In one embodiment, the feedback circuit includes a second resistor and a second capacitor, the second resistor and the second capacitor are connected in parallel, and the two connection ends of the second resistor and the second capacitor after being connected in parallel are electrically connected to the negative input terminal and the output terminal of the operational amplifier respectively.

[0030] Compared with the prior art, the present invention provides an intelligent interactive tablet, which includes a plurality of piezoelectric sensors arranged in parallel, and the plurality of piezoelectric sensors are installed under the glass on the inner surface of the touch screen of the intelligent interactive tablet; a plurality of detection circuit modules corresponding to the plurality of piezoelectric sensors; wherein: the detection circuit module includes a signal transmitting circuit, a piezoelectric sensor channel circuit, an operation circuit processor and a first voltage reference terminal; the piezoelectric sensor channel circuit includes a signal isolation circuit, a first access terminal and a second access terminal; the first access terminal and the second access terminal are respectively used to access the first terminal and the second terminal of the piezoelectric sensor; the signal isolation circuit is electrically connected to the output terminal of the signal transmitting circuit, and is used to prevent the piezoelectric sensor from The sensor signal flows into the signal transmitting circuit; the output end of the signal isolation circuit is a first access end; the second access end is electrically connected to the first voltage reference end; the operation circuit is electrically connected to the signal isolation circuit, the first voltage reference end, and the processor, respectively, for outputting a conditioned voltage signal to the processor; the processor is configured to determine the state of the piezoelectric sensor based on the conditioned voltage signal, specifically: when the conditioned voltage signal is higher than a preset threshold, the piezoelectric sensor is determined to be in a normal state; when the conditioned voltage signal is lower than the preset threshold, the piezoelectric sensor is determined to be in an abnormal state; and when the number of piezoelectric sensors in the abnormal state is lower than a set value, the processor shields the signal transmitted by the piezoelectric sensor in the abnormal state. Thus, by connecting the piezoelectric sensor to the first access end and the second access end of the piezoelectric sensor channel circuit; after the piezoelectric sensor is connected to the detection circuit, the signal transmitting circuit outputs a signal to turn on the signal isolation circuit, thereby achieving real-time detection of the piezoelectric sensor and causing the signal conditioning circuit to output a conditioned voltage signal to the processor, and the processor determines the state of the piezoelectric sensor based on the change between the conditioned voltage signal data and the piezoelectric sensor intact state data. Therefore, during the production process, it is possible to directly detect whether the piezoelectric sensor has a poor electrical connection, intercept the poor electrical connection of the piezoelectric sensor in the previous process, avoid the trouble of subsequent disassembly, and improve production efficiency. If the poor electrical connection of the piezoelectric sensor is detected at the user end, the processor can be used to shield these piezoelectric sensors with poor electrical connection, so as to ensure that the recognition rate is within a controllable range as much as possible. This can solve the problem that when the piezoelectric sensor of the existing interactive tablet is detected to have a poor electrical connection after assembly, the piezoelectric sensor installed under the inner surface glass of the touch screen needs to be disassembled, which is cumbersome and affects production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0032] FIG1 is a schematic structural diagram of a piezoelectric sensor;

[0033] FIG2 is a schematic diagram of an equivalent circuit of a piezoelectric sensor in current source mode;

[0034] FIG3 is a schematic diagram of an equivalent circuit of a piezoelectric sensor in voltage source mode;

[0035] FIG4 is a schematic structural diagram of a smart interactive tablet provided by the present invention;

[0036] FIG5 is another structural diagram of a smart interactive tablet provided by the present invention;

[0037] FIG6 is a first circuit diagram of a detection circuit module of a smart interactive tablet provided by the present invention;

[0038] FIG7 is a second circuit diagram of a detection circuit module of a smart interactive tablet provided by the present invention;

[0039] FIG8 is a third circuit diagram of a detection circuit module of a smart interactive tablet provided by the present invention;

[0040] FIG9 is a schematic diagram of a detection circuit module of a smart interactive tablet provided by the present invention detecting that a piezoelectric sensor is in an open circuit state;

[0041] FIG10 is a schematic diagram of a detection circuit module of a smart interactive tablet provided by the present invention detecting that a piezoelectric sensor is in a short-circuit state;

[0042] FIG11 is a schematic diagram of a detection circuit module of a smart interactive tablet provided by the present invention detecting that a piezoelectric sensor is in a broken state;

[0043] FIG12 is another structural diagram of a smart interactive tablet provided by the present invention.

[0044] Key component symbol description: Detection circuit module 1, signal transmission circuit 11, piezoelectric sensor channel circuit 12, signal isolation circuit 123, first access terminal IN1, second access terminal IN2, transistor Q1, first resistor R1, second resistor R2, third resistor R3, fourth resistor R4, operational circuit 13, current limiting circuit 131, signal conditioning circuit 132, feedback circuit 1321, MOS tube Q2, second capacitor C2, third capacitor C3, operational amplifier P1, piezoelectric sensor C1, processor 15, smart interactive tablet 100 DETAILED DESCRIPTION

[0045] In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as being "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "upper", "lower", "inner", "outer", "bottom" and the like used in this specification indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0046] Unless otherwise defined, all technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification and in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the relevant listed items.

[0047] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0048] In some large-sized smart interactive tablets, piezoelectric sensors are generally used to detect user touch gestures on the touch screen to perform different interactive functions. Piezoelectric sensors have become one of the necessary components of smart interactive tablets.

[0049] Based on the principle of piezoelectric sensors detecting vibrations, the elastic waves generated by a stylus pen writing on the touchscreen of a smart interactive tablet can be measured. The piezoelectric sensor detects frequency differences to determine the writing material, such as finger, pen tip, or pen end. The current writing is then assigned an ID to enable different interactive functions. For example, a finger can circle and slide, the pen tip can start writing, and the pen end can erase.

[0050] Piezoelectric sensors are generally pasted and installed under the inner surface glass of the smart interactive flat panel touch screen. During the research and development process, the inventors found that due to the internal size limitations of the smart interactive flat panel touch screen, the piezoelectric sensor needs to be kept within a relatively small size and thickness. This leads to various problems with the installation, electrical connection, and structure of the piezoelectric sensor. For example, during the installation process and during the transportation and use of the smart interactive flat panel, the piezoelectric sensor receives various vibrations, which may lead to poor electrical connection, breakage, and short circuits of the piezoelectric sensor. During the touch screen assembly process, the piezoelectric sensor may have poor electrical connection. Once a smart interactive flat panel is equipped with a piezoelectric sensor that may have poor electrical connection, the touch screen recognition rate will be misaligned, which will reduce product quality and affect the user experience. Currently, poor electrical connections in piezoelectric sensors can only be detected after the entire smart interactive tablet is installed. To detect such problems, the device must be disassembled to remove the piezoelectric sensor, located beneath the innermost glass surface of the touchscreen. This requires first removing the entire device's frame, back panel, rear cover, and midframe. Only after removing the inner glass surface of the touchscreen can the piezoelectric sensor underneath be removed. This disassembly process is cumbersome, labor-intensive, and impacts production efficiency. Furthermore, since large-scale smart interactive tablets typically require multiple piezoelectric sensors, the inspection process requires checking each one individually, which is labor-intensive and time-consuming.

[0051] To this end, in response to the above-mentioned technical problems discovered during the research and development process, an embodiment of the present application provides a smart interactive tablet, including multiple piezoelectric sensors arranged in parallel, the multiple piezoelectric sensors being installed under the glass on the inner surface of the touch screen of the smart interactive tablet; multiple detection circuit modules corresponding to the multiple piezoelectric sensors; wherein: the detection circuit module includes a signal transmission circuit, a piezoelectric sensor channel circuit, an operation circuit and a processor; the piezoelectric sensor channel circuit includes a signal isolation circuit, which connects the piezoelectric sensor to the first access terminal and the second access terminal of the piezoelectric sensor channel circuit; after the piezoelectric sensor is connected to the detection circuit module, the signal transmission circuit outputs a signal to turn on the signal isolation circuit, thereby achieving real-time detection of the piezoelectric sensor, and causing the operation circuit to output a conditioned voltage signal to the processor, which determines the status of the piezoelectric sensor based on the change in the conditioned voltage signal data and the piezoelectric sensor intact status data. In this way, whether the piezoelectric sensor is poorly electrically connected can be directly detected during the production process, and the poor electrical connection of the piezoelectric sensor can be intercepted in the previous process, avoiding the trouble of subsequent disassembly and improving production efficiency. If the number of poorly connected piezoelectric sensors detected at the user end is lower than a set value, the processor can be used to shield the piezoelectric sensors with poor electrical connections, and only use the piezoelectric sensor signals in normal state, so as to ensure that the signal recognition rate is maintained within a controllable range as much as possible. This can solve the problem that when the existing smart interactive tablet detects poor electrical connection of the piezoelectric sensor after assembly, the piezoelectric sensor installed under the inner surface glass of the touch screen needs to be disassembled, which is cumbersome and affects production efficiency. Furthermore, the embodiment of the present application can also diagnose four different states of the piezoelectric sensor based on the conditioned voltage signal, namely normal working state, short circuit, open circuit and sensor breakage. Subsequently, corresponding maintenance can be performed according to the different diagnosed states, which greatly reduces the cost of fault identification and maintenance and improves work efficiency. In addition, the smart interactive tablet of the present application also uses piezoelectric sensors and detection circuit modules arranged in parallel. When the processor determines the detection result, it can also locate the faulty sensor, greatly improving the efficiency of detection and maintenance.

[0052] In order to facilitate understanding of the above inventive concept of the present invention, the above inventive concept of the present invention is described in more detail below with reference to the accompanying drawings and specific embodiments.

[0053] Figure 1 shows a schematic diagram of the structure of a piezoelectric sensor. In Figure 1, the piezoelectric sensor includes a central piezoelectric ceramic material, an upper electrode disposed above the piezoelectric ceramic material, and a lower electrode disposed below the piezoelectric ceramic material. The upper electrode, lower electrode, and central ceramic insulating material form a capacitor. When the piezoelectric sensor is connected to a back-end analog signal processing circuit (such as the detection circuit module of this patent), the piezoelectric sensor can use the equivalent capacitor Cp as part of the circuit.

[0054] When physical pressure is applied to the piezoelectric ceramic material that makes up the piezoelectric sensor, the electric dipole moment in the piezoelectric ceramic material will shorten due to compression. At this time, the piezoelectric ceramic material will generate equal amounts of positive and negative charges on the opposite surfaces of the piezoelectric ceramic material to resist this change and maintain its original state.

[0055] Figure 2 shows the equivalent circuit of a piezoelectric sensor in current source mode. In current source mode, it can be expressed as follows: Ip = dQ / dt

[0056] In the above formula, Ip represents the differential of the amount of charge generated by the piezoelectric sensor per unit time, Q represents the charge generated by the piezoelectric sensor during pressing, Cp represents the equivalent capacitance of the piezoelectric sensor, and Rp represents the leakage resistance of the piezoelectric sensor (although the resistance of piezoelectric ceramics is large, it is not infinite and cannot be completely regarded as an ideal capacitor).

[0057] For ease of calculation, the equivalent circuit of the piezoelectric sensor in current source mode shown in Figure 2 can be replaced by the equivalent circuit of the piezoelectric sensor in voltage source mode shown in Figure 3. In Figure 3, the piezoelectric sensor equivalent capacitance Cp is connected in parallel with the piezoelectric sensor leakage resistance Rp. The values ​​of the piezoelectric sensor equivalent capacitance Cp and the piezoelectric sensor leakage resistance Rp can be obtained using a digital bridge test. The piezoelectric sensor leakage resistance Rp is extremely large and can be ignored in a circuit where the piezoelectric sensor equivalent capacitance Cp and the piezoelectric sensor leakage resistance Rp are connected in parallel. When physical pressure is applied to the piezoelectric ceramic material that makes up the piezoelectric sensor, the electric dipole moment within the piezoelectric ceramic material shortens due to compression. To counteract this change, the piezoelectric ceramic material generates equal amounts of positive and negative charges on opposite surfaces of the piezoelectric ceramic material. The generated equal amounts of positive and negative charges can then be sampled by a connected back-end analog signal processing circuit and converted into corresponding voltage signals for subsequent processing.

[0058] In one embodiment, as shown in FIG4 , the present invention provides a smart interactive tablet 100, which includes: a plurality of piezoelectric sensors C1 arranged in parallel, the plurality of piezoelectric sensors C1 being installed below the glass on the inner surface of the touch screen of the smart interactive tablet; a plurality of detection circuit modules 1 corresponding one-to-one to the plurality of piezoelectric sensors C1; wherein:

[0059] The detection circuit module 1 includes a signal transmitting circuit 11, a piezoelectric sensor channel circuit 12, an operation circuit 13, a processor 15 and a first voltage reference terminal VDD, wherein:

[0060] The piezoelectric sensor channel circuit 12 includes a signal isolation circuit 123, a first access terminal IN1, and a second access terminal IN2; the first access terminal IN1 and the second access terminal IN2 are respectively used to connect to the first end and the second end of the piezoelectric sensor C1; the signal isolation circuit 123 is electrically connected to the output terminal of the signal transmitting circuit 11 to prevent the piezoelectric sensor signal from flowing into the signal transmitting circuit 11; the output terminal of the signal isolation circuit 123 is the first access terminal IN1; the second access terminal IN2 is electrically connected to the first voltage reference terminal VDD;

[0061] The operation circuit 13 is electrically connected to the signal isolation circuit 123, the first voltage reference terminal VDD and the processor 15, respectively, for outputting a conditioned voltage signal to the processor 15;

[0062] The processor 15 is used to determine the state of the piezoelectric sensor C1 based on the conditioned voltage signal; specifically: when the conditioned voltage signal is higher than a preset threshold, the piezoelectric sensor is determined to be in a normal state; when the conditioned voltage signal is lower than the preset threshold, the piezoelectric sensor is determined to be in an abnormal state, and when the number of piezoelectric sensors in an abnormal state is lower than a set value, the processor blocks the signal transmitted by the piezoelectric sensor in the abnormal state.

[0063] In this embodiment, a smart interactive tablet is provided, comprising a plurality of piezoelectric sensors arranged in parallel, wherein the plurality of piezoelectric sensors are installed under the glass on the inner surface of the touch screen of the smart interactive tablet; a plurality of detection circuit modules corresponding to the plurality of piezoelectric sensors; wherein: the detection circuit module comprises a signal transmitting circuit, a piezoelectric sensor channel circuit, an operation circuit processor and a first voltage reference terminal; the piezoelectric sensor channel circuit comprises a signal isolation circuit, a first access terminal and a second access terminal; the first access terminal and the second access terminal are respectively used to access the first terminal and the second terminal of the piezoelectric sensor; the signal isolation circuit is electrically connected to the output terminal of the signal transmitting circuit, and is used to prevent the piezoelectric sensor signal from flowing The signal transmitting circuit is connected to the signal isolation circuit; the output end of the signal isolation circuit is a first access end; the second access end is electrically connected to the first voltage reference end; the operation circuit is electrically connected to the signal isolation circuit, the first voltage reference end, and the processor, respectively, for outputting a conditioned voltage signal to the processor; the processor is configured to determine the state of the piezoelectric sensor based on the conditioned voltage signal, specifically: when the conditioned voltage signal is higher than a preset threshold, the piezoelectric sensor is determined to be in a normal state; when the conditioned voltage signal is lower than the preset threshold, the piezoelectric sensor is determined to be in an abnormal state; and when the number of piezoelectric sensors in the abnormal state is lower than a set value, the processor shields the signal transmitted by the piezoelectric sensor in the abnormal state. Thus, by connecting the piezoelectric sensor to the first access end and the second access end of the piezoelectric sensor channel circuit; after the piezoelectric sensor is connected to the detection circuit module, the signal transmitting circuit outputs a signal to turn on the signal isolation circuit, thereby achieving real-time detection of the piezoelectric sensor and causing the signal conditioning circuit to output a conditioned voltage signal to the processor. The processor determines the state of the piezoelectric sensor based on the change between the conditioned voltage signal data and the piezoelectric sensor intact state data. Therefore, during the production process, it is possible to directly detect whether the piezoelectric sensor has a poor electrical connection, intercept the poor electrical connection of the piezoelectric sensor in the previous process, avoid the trouble of subsequent disassembly, and improve production efficiency. If the poor electrical connection of the piezoelectric sensor is detected at the user end, the processor can be used to shield these piezoelectric sensors with poor electrical connection, so as to ensure that the recognition rate is within a controllable range as much as possible. This can solve the problem that when the piezoelectric sensor of the existing interactive tablet is detected to have a poor electrical connection after assembly, the piezoelectric sensor installed under the inner surface glass of the touch screen needs to be disassembled, which is cumbersome and affects production efficiency.

[0064] In one embodiment, 4-6 piezoelectric sensors are arranged in parallel, and more can be arranged as needed.

[0065] In one embodiment, when the processor shields the signal transmitted by the piezoelectric sensor in the abnormal state, the set value of the piezoelectric sensor in the abnormal state depends on the number of the piezoelectric sensors.

[0066] In one embodiment, the piezoelectric sensor detection circuit modules arranged in parallel may share the same signal transmitting circuit and processor, or each piezoelectric sensor detection circuit module may be provided with a separate signal transmitting circuit and processor.

[0067] In one embodiment, the signal transmitting circuit 11 is electrically connected to the signal isolation circuit 123 of each piezoelectric sensor channel circuit 12 to stimulate a short square wave pulse signal to the signal isolation circuit 123 .

[0068] Specifically, as shown in Figure 6, the signal transmitting circuit 11 includes at least one GPIO (General Purpose Input Output) port, which is electrically connected to the signal isolation circuit 123 of the piezoelectric sensor channel circuit 12 and is used to stimulate a short square wave pulse signal to the signal isolation circuit 123.

[0069] In one embodiment, when the detection circuit module 1 includes multiple piezoelectric sensor channel circuits, the GPIO port is electrically connected to the signal isolation circuit 123 of each piezoelectric sensor channel circuit 12, respectively, for stimulating a short square wave pulse signal to the signal isolation circuit 123 of each piezoelectric sensor channel circuit.

[0070] The signal transmitting circuit excites a short square wave pulse signal to the signal isolation circuit to turn on the signal isolation circuit, thereby achieving real-time detection of the piezoelectric sensor connected to the piezoelectric sensor channel circuit.

[0071] In one embodiment, the piezoelectric sensor channel circuit 12 includes a signal isolation circuit 123, a first access terminal IN1, and a second access terminal IN2; the first access terminal IN1 and the second access terminal IN2 are respectively used to connect to the first and second terminals of the piezoelectric sensor; the signal isolation circuit 123 is electrically connected to the output terminal of the signal transmitting circuit 11, and the output terminal of the signal isolation circuit 123 is the first access terminal IN1; the second access terminal IN2 is electrically connected to the first voltage reference terminal VDD. The signal isolation circuit 123 is used to transmit the signal from the signal transmitting circuit to the piezoelectric sensor and the subsequent current limiting circuit 131, and to block the signal from the piezoelectric sensor from flowing into the signal transmitting circuit 11.

[0072] Specifically, as shown in Figure 6, as an optional example, the signal isolation circuit 123 includes a transistor Q1 and a third resistor R3, the base of the transistor Q1 is electrically connected to the GPIO port, the collector of the transistor Q1 is electrically connected to the second reference voltage terminal VCC through the third resistor R3, and the emitter of the transistor Q1 is the first access terminal IN1; wherein, the reference voltage of the second reference voltage terminal VCC is greater than the reference voltage of the first reference voltage terminal VDD. For example, the reference voltage of the second reference voltage terminal VCC is twice the reference voltage of the first reference voltage terminal VDD.

[0073] As shown in FIG7 , as another optional example, the signal isolation circuit 123 includes a MOS transistor Q2 and a fourth resistor R4. The gate of the MOS transistor Q2 is electrically connected to the GPIO port, the drain of the MOS transistor Q2 is electrically connected to the second reference voltage terminal VCC via the fourth resistor R4, and the source of the MOS transistor Q2 is the first access terminal IN1. The reference voltage of the second reference voltage terminal VCC is greater than the reference voltage of the first reference voltage terminal VDD. For example, the reference voltage of the second reference voltage terminal VCC is twice the reference voltage of the first reference voltage terminal VDD.

[0074] It is understandable that the MOS transistor Q2 can be a P-type MOS transistor or an N-type MOS transistor. In Figure 7, the MOS transistor Q2 is described using a P-type MOS transistor as an example, but it should not be limited to a P-type MOS transistor. The same effect can be achieved using an N-type MOS transistor, which will not be described in detail here.

[0075] As shown in Figure 8, as another optional example, when the signal transmitted by the signal transmitting circuit is a high-frequency signal, the signal isolation circuit 123 includes a third capacitor C3. At this time, the third capacitor can pass the high-frequency signal and block the low-frequency signal of the piezoelectric sensor; the sensor signal cannot flow into the signal transmitting circuit, and the high-frequency signal of the signal transmitting circuit can flow into the back-end circuit; the first end of the third capacitor C3 is electrically connected to the GPIO port, and the second end of the third capacitor C3 is the first access end IN1.

[0076] In one embodiment, the operation circuit 13 is electrically connected to the signal isolation circuit 123 , the first voltage reference terminal VDD, and the processor 15 , respectively, for outputting a conditioned voltage signal to the processor 15 .

[0077] Specifically, as shown in FIG5 , the operational circuit 13 is an operational amplifier circuit, including a current limiting circuit 131 and a signal conditioning circuit 132 , wherein:

[0078] The current limiting circuit 131 is electrically connected to the output end of the signal isolation circuit 123. The current limiting circuit 131 serves to limit the current of the signal of the signal transmitting circuit 11 transmitted through the signal isolation circuit 123, so as to avoid impacting the operational amplifier P1 in the signal conditioning circuit 132 and damaging the operational amplifier P1. Specifically, as shown in Figures 6 to 11, the current limiting circuit 131 includes a first resistor R1, which is electrically connected to the output end of the signal isolation circuit 123 of the piezoelectric sensor channel circuit 12. The signal of the signal transmitting circuit 11 transmitted through the signal isolation circuit 123 is limited by the first resistor R1, so as to avoid impacting the operational amplifier P1 in the signal conditioning circuit 132 and damaging the operational amplifier P1.

[0079] In one embodiment, when the detection circuit module 1 includes multiple piezoelectric sensor channel circuits, the first resistor R1 is electrically connected to the output end of the signal isolation circuit of each piezoelectric sensor channel circuit.

[0080] The signal conditioning circuit 132 is electrically connected to the current limiting circuit 131 , the first voltage reference terminal VDD, and the processor 15 , respectively, for outputting a conditioned voltage signal to the processor 15 .

[0081] Specifically, the signal conditioning circuit 132 includes a first signal input terminal, a second signal input terminal and an output terminal. The first signal input terminal is electrically connected to the current limiting circuit 131, and the second signal input terminal is electrically connected to the first voltage reference terminal VDD. The output terminal of the signal conditioning circuit is used to output a conditioned voltage signal for the processor 15 to determine the state of the piezoelectric sensor based on the conditioned voltage signal.

[0082] In one embodiment, as shown in Figures 6 to 11, the signal conditioning circuit 132 includes an operational amplifier P1 and a feedback circuit 1321; the positive input terminal of the operational amplifier P1 is electrically connected to the first voltage reference terminal VDD as the second signal input terminal, and the negative input terminal of the operational amplifier P1 is electrically connected to the current limiting circuit 131 as the first signal input terminal. Specifically, the negative input terminal of the operational amplifier P1 is electrically connected to the first resistor R1 as the first signal input terminal; the output terminal OUT of the operational amplifier P1 is electrically connected to the negative input terminal of the operational amplifier P1 through the feedback circuit 1321, and the output terminal OUT of the operational amplifier P1 is used to output a conditioned voltage signal for the processor 15 to determine the state of the piezoelectric sensor based on the conditioned voltage signal.

[0083] In one embodiment, the feedback circuit 1321 includes a second resistor R2 and a second capacitor C2, wherein the second resistor R2 and the second capacitor C2 are connected in parallel, and the two connection ends of the second resistor R2 and the second capacitor C2 are electrically connected to the negative input terminal and the output terminal OUT of the operational amplifier P1, respectively.

[0084] In one embodiment, the processor 15 is electrically connected to the signal conditioning circuit 132, and is used to determine the state of the piezoelectric sensor based on the conditioned voltage signal output by the signal conditioning circuit 132; specifically: when the conditioned voltage signal is higher than a preset threshold, the piezoelectric sensor is determined to be in a normal state; when the conditioned voltage signal is lower than the preset threshold, the piezoelectric sensor is determined to be in an abnormal state, and when the number of the piezoelectric sensors in the abnormal state is lower than a set value, the processor blocks the signal transmitted by the piezoelectric sensor in the abnormal state.

[0085] Specifically, the processor 15 is electrically connected to the output terminal OUT of the operational amplifier P1 in the signal conditioning circuit 132 , and is configured to determine the state of the piezoelectric sensor according to the conditioned voltage signal output by the operational amplifier P1 .

[0086] The processor 15 has data processing capabilities and signal processing capabilities, and can be an integrated circuit chip. For example, the processor can be a general-purpose processor, a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array) or other programmable logic devices, etc. The general-purpose processor can be a microprocessor, an MCU (Microcontroller Unit) or any conventional processor, etc.

[0087] Generally speaking, piezoelectric sensor states include normal, open, short-circuited, and broken. The processor pre-stores voltage signal data corresponding to the piezoelectric sensor's normal, open, short-circuited, and broken states. Upon receiving the conditioned voltage signal output by the operational amplifier P1, the processor 15 may compare the conditioned voltage signal output by the operational amplifier P1 with the pre-stored voltage signal data to determine the state of the piezoelectric sensor.

[0088] Figure 6 also shows a schematic diagram of the detection circuit module when the piezoelectric sensor is in a normal state. In Figure 6, the piezoelectric sensor is indicated by the reference symbol C1. When the piezoelectric sensor C1 is connected to the detection circuit module 1, and if the piezoelectric sensor C1 is in a normal state, the piezoelectric sensor C1 is electrically connected to the detection circuit module 1. At this point, when the signal transmitting circuit 11 stimulates a signal to the base of transistor Q1, turning on transistor Q1, the voltage generated by the reference voltage at the second reference voltage terminal VCC, after passing through the third resistor R3 and transistor Q1, is applied to the first input terminal IN1 of the piezoelectric sensor channel circuit 12. At this point, the capacitance of the piezoelectric sensor C1 is equal to the capacitance of the piezoelectric sensor equivalent capacitor Cp, and the current generated by the first input terminal IN1 flows to the first resistor R1 and the piezoelectric sensor C1, respectively. The voltage of the piezoelectric sensor C1 rises after the current flows in. When the voltage rises to a certain level, transistor Q1 turns off. At this point, the detection circuit module 1 slowly discharges through the first resistor R1 and the second resistor R2. At this time, because the voltage of the piezoelectric sensor C1 increases after the current flows into it, the voltage input from the first reference voltage terminal VDD to the positive input terminal of the operational amplifier P1 exceeds the voltage input from the first resistor R1 to the negative input terminal of the operational amplifier P1. The output terminal OUT of the operational amplifier P1 outputs a first conditioned voltage signal of a first high level and transmits it to the processor 15. Upon receiving the first conditioned voltage signal output by the operational amplifier P1, the processor 15 compares the first conditioned voltage signal with pre-stored voltage signal data, determines that the piezoelectric sensor C1 is in a normal state, and thus determines the current state of the piezoelectric sensor.

[0089] Figure 9 shows a schematic diagram of the detection circuit module when the piezoelectric sensor is in the off-circuit state. In Figure 9, the piezoelectric sensor is designated by the reference symbol C1. When piezoelectric sensor C1 is connected to the detection circuit module 1, if piezoelectric sensor C1 is in the off-circuit state, piezoelectric sensor C1 is not actually connected to the detection circuit module 1. At this point, when the signal transmitting circuit 11 activates a signal to the base of transistor Q1, turning transistor Q1 on, the voltage generated by the second reference voltage VCC after passing through the third resistor R3 and transistor Q1 is applied to the first input terminal IN1 of the piezoelectric sensor channel circuit 12. At this point, because the piezoelectric sensor C1 is in the off-circuit state, the current generated by the first input terminal IN1 flows only into the first resistor R1 and not into the piezoelectric sensor C1. At this point, the voltage input from the first resistor R1 to the negative input terminal of the operational amplifier P1 exceeds the voltage input from the first reference voltage terminal VDD to the positive input terminal of the operational amplifier P1. The output terminal OUT of the operational amplifier P1 outputs a low-level second conditioned voltage signal, which is transmitted to the processor 15. When the processor 15 receives the second conditioned voltage signal output by the operational amplifier P1, it compares the second conditioned voltage signal with pre-stored voltage signal data to determine that the piezoelectric sensor C1 is in an open circuit state, thereby determining the current state of the piezoelectric sensor.

[0090] As shown in Figure 10, it is a detection schematic diagram of the detection circuit module when the piezoelectric sensor is in a short-circuit state. In Figure 10, the piezoelectric sensor is represented by the label C1. When the piezoelectric sensor C1 is connected to the detection circuit module 1, if the piezoelectric sensor C1 is in a short-circuit state, the piezoelectric sensor C1 is bypassed by the detection circuit module 1. At this time, the emitter of the transistor Q1 is directly electrically connected to the first reference terminal VDD. When the signal transmitting circuit 11 stimulates a pulse signal to the base of the transistor Q1 and turns on the transistor Q1, the voltage generated by the second reference voltage VCC after passing through the third resistor R3 and the transistor Q1 will be applied to the first access terminal IN1 of the piezoelectric sensor channel circuit. At this time, since the piezoelectric sensor C1 is in a short-circuit state, the third resistor R3 acts as a current limiter. The current generated by the first input terminal IN1 flows to the first reference voltage terminal VDD and the first resistor R1, causing the voltage of the first reference voltage terminal VDD to exceed the voltage input to the negative input terminal of the operational amplifier P1 by the first resistor R1. The output terminal OUT of the operational amplifier P1 outputs a third conditioned voltage signal of a second high level and transmits it to the processor 15. Upon receiving the third conditioned voltage signal output by the operational amplifier P1, the processor 15 compares the third conditioned voltage signal with pre-stored voltage signal data, determines that the piezoelectric sensor C1 is in a short-circuit state, and thereby determines the current state of the piezoelectric sensor.

[0091] As shown in Figure 11, it is a detection schematic diagram of the detection circuit module when the piezoelectric sensor is in a broken state. In Figure 11, the piezoelectric sensor is represented by the label C1. When the piezoelectric sensor C1 is connected to the detection circuit module 1, if the piezoelectric sensor C1 is in a broken state, the piezoelectric sensor C1 is in an electrically connected state with the detection circuit module 1, but the capacitance value of the piezoelectric sensor C1 will be reduced accordingly (for example, the capacitance value of the piezoelectric sensor C1 is reduced to half of the capacitance value of the piezoelectric sensor equivalent capacitance Cp, and the capacitance change is related to the breakage ratio). At this time, when the signal transmitting circuit 11 stimulates a signal to the base of the transistor Q1 and turns on the transistor Q1, the voltage generated after the second reference voltage VCC passes through the third resistor R3 and the transistor Q1 will be applied to the first access terminal IN1 of the piezoelectric sensor channel circuit. At this time, the current generated by the first input terminal IN1 will flow to the first resistor R1 and the piezoelectric sensor C1 respectively. Since the piezoelectric sensor C1 is in a broken state, the capacitance value of the piezoelectric sensor C1 will correspondingly decrease, causing the ratio of the current flowing to the first resistor R1 and the current flowing into the piezoelectric sensor C1 to further change. At this time, since the voltage of the piezoelectric sensor C1 will rise after the current flows into the piezoelectric sensor C1, the voltage input to the positive input terminal of the operational amplifier P1 by the first reference voltage terminal VDD exceeds the voltage input to the negative input terminal of the operational amplifier P1 by the first resistor R1. The output terminal OUT of the operational amplifier P1 outputs a fourth conditioned voltage signal of a second high level and transmits it to the processor 15. Upon receiving the fourth conditioned voltage signal output by the operational amplifier P1, the processor 15 compares the fourth conditioned voltage signal with the pre-stored voltage signal data, determines that the piezoelectric sensor C1 is in a broken state, and thus determines the current state of the piezoelectric sensor.

[0092] Based on the same concept, in one embodiment, as shown in FIG12 , the present invention further provides a smart interactive tablet 100, comprising: a plurality of piezoelectric sensors mounted below the glass on the inner surface of the touch screen of the smart interactive tablet; a plurality of detection circuit modules 1 corresponding one-to-one to the plurality of piezoelectric sensors; wherein:

[0093] The detection circuit module 1 includes: a signal transmitting circuit 11, a piezoelectric sensor channel circuit 12, an operation circuit 13, a first voltage reference terminal VDD and a processor 15;

[0094] The signal transmitting circuit 11 includes a plurality of pairs of differential signals, each pair of differential signals includes a first differential signal output terminal D+ and a second differential signal output terminal D-;

[0095] Each piezoelectric sensor channel circuit 12 includes a first access terminal IN1 and a second access terminal IN2; the first access terminal IN1 and the second access terminal IN2 are used to connect to the first end and the second end of the piezoelectric sensor C1; the first access terminal IN1 and the second access terminal IN2 are respectively electrically connected to the first differential signal output terminal D+ and the second differential signal output terminal D- of a pair of differential signals of the signal transmitting circuit 11, that is, the first access terminal IN1 is electrically connected to the first differential signal output terminal D+ of a pair of differential signals of the signal transmitting circuit 11, and the second access terminal IN2 is electrically connected to the second differential signal output terminal D- of the same pair of differential signals of the signal transmitting circuit 11;

[0096] The operation circuit 13 is electrically connected to each of the piezoelectric sensor channel circuits 12, the first voltage reference terminal VDD, and the processor 15, and is configured to output a conditioned voltage signal to the processor 15;

[0097] The processor 15 is used to determine the state of the piezoelectric sensor based on the conditioned voltage signal; specifically: when the conditioned voltage signal is higher than a preset threshold, the piezoelectric sensor is determined to be in a normal state; when the conditioned voltage signal is lower than the preset threshold, the piezoelectric sensor is determined to be in an abnormal state; when the number of the piezoelectric sensors in the abnormal state is lower than a set value, the processor blocks the signals transmitted by the piezoelectric sensors in the abnormal state.

[0098] In one embodiment, the signal transmitting circuit 11 is electrically connected to each piezoelectric sensor channel circuit 12 and includes multiple pairs of short square wave pulse differential signals. Each pair of short square wave pulse differential signals includes a first differential signal output terminal D+ and a second differential signal output terminal D-. The signal transmitting circuit 11 is used to generate multiple pairs of short square wave pulse differential signals, and each pair of short square wave pulse differential signals is sent to each piezoelectric sensor channel circuit 12. This enables real-time detection of the piezoelectric sensor C1 connected to each piezoelectric sensor channel circuit 12.

[0099] In one embodiment, the operation circuit 13 is electrically connected to the signal isolation circuit 123 , the first voltage reference terminal VDD, and the processor 15 , respectively, for outputting a conditioned voltage signal to the processor 15 .

[0100] Specifically, as shown in FIG5 , the operational circuit 13 is an operational amplifier circuit, including a current limiting circuit 131 and a signal conditioning circuit 132 , wherein:

[0101] The current limiting circuit 131 is electrically connected to the output end of the signal isolation circuit 123. The current limiting circuit 131 serves to limit the current of the signal of the signal transmitting circuit 11 transmitted through the signal isolation circuit 123, so as to avoid impacting the operational amplifier P1 in the signal conditioning circuit 132 and damaging the operational amplifier P1. Specifically, as shown in Figures 6 to 11, the current limiting circuit 131 includes a first resistor R1, which is electrically connected to the output end of the signal isolation circuit 123 of the piezoelectric sensor channel circuit 12. The signal of the signal transmitting circuit 11 transmitted through the signal isolation circuit 123 is limited by the first resistor R1, so as to avoid impacting the operational amplifier P1 in the signal conditioning circuit 132 and damaging the operational amplifier P1.

[0102] In one embodiment, when the detection circuit module 1 includes multiple piezoelectric sensor channel circuits, the first resistor R1 is electrically connected to the output end of the signal isolation circuit of each piezoelectric sensor channel circuit.

[0103] The signal conditioning circuit 132 is electrically connected to the current limiting circuit 131 , the first voltage reference terminal VDD, and the processor 15 , respectively, for outputting a conditioned voltage signal to the processor 15 .

[0104] Specifically, the signal conditioning circuit 132 includes a first signal input terminal, a second signal input terminal and an output terminal. The first signal input terminal is electrically connected to the current limiting circuit 131, and the second signal input terminal is electrically connected to the first voltage reference terminal VDD. The output terminal of the signal conditioning circuit is used to output a conditioned voltage signal for the processor 15 to determine the state of the piezoelectric sensor based on the conditioned voltage signal.

[0105] In one embodiment, as shown in Figures 6 to 11, the signal conditioning circuit 132 includes an operational amplifier P1 and a feedback circuit 1321; the positive input terminal of the operational amplifier P1 is electrically connected to the first voltage reference terminal VDD as the second signal input terminal, and the negative input terminal of the operational amplifier P1 is electrically connected to the current limiting circuit 131 as the first signal input terminal. Specifically, the negative input terminal of the operational amplifier P1 is electrically connected to the first resistor R1 as the first signal input terminal; the output terminal OUT of the operational amplifier P1 is electrically connected to the negative input terminal of the operational amplifier P1 through the feedback circuit 1321, and the output terminal OUT of the operational amplifier P1 is used to output a conditioned voltage signal for the processor 15 to determine the state of the piezoelectric sensor based on the conditioned voltage signal.

[0106] In one embodiment, the feedback circuit 1321 includes a second resistor R2 and a second capacitor C2, wherein the second resistor R2 and the second capacitor C2 are connected in parallel, and the two connection ends of the second resistor R2 and the second capacitor C2 are electrically connected to the negative input terminal and the output terminal OUT of the operational amplifier P1, respectively.

[0107] In one embodiment, the signal transmitting circuit transmits signals of different frequency combinations. After the signal passes through the detection circuit, the processor calculates the cross-correlation between the received conditioned voltage signal and the preset signal. When the calculated value is greater than the preset threshold, the piezoelectric sensor is judged to be in a normal state. When the calculated result is lower than the preset threshold, the piezoelectric sensor is judged to be in an abnormal state. When the number of the piezoelectric sensors in the abnormal state is lower than the set value, the processor blocks the signals transmitted by the piezoelectric sensors in the abnormal state.

[0108] In this embodiment, a smart interactive tablet is provided, comprising: a plurality of piezoelectric sensors, the plurality of piezoelectric sensors being mounted below the glass on the inner surface of the touch screen of the smart interactive tablet; a plurality of detection circuit modules corresponding one to one with the plurality of piezoelectric sensors; wherein: the detection circuit module comprises: a signal transmitting circuit, a piezoelectric sensor channel circuit, an operation circuit, a first voltage reference terminal and a processor; the signal transmitting circuit comprises a plurality of pairs of differential signals, each pair of differential signals comprising a first differential signal output terminal and a second differential signal output terminal; each of the piezoelectric sensor channel circuits comprises a first access terminal and a second access terminal; the first access terminal and the second access terminal are used to connect to the first and second terminals of the piezoelectric sensor; the first access terminal and the second access terminal are respectively connected to the first differential signal output terminal and the second differential signal output terminal of a pair of differential signals of the signal transmitting circuit The signal output terminal is electrically connected, i.e., the first access terminal is electrically connected to the first differential signal output terminal of a pair of differential signals of the signal transmission circuit, and the second access terminal is electrically connected to the second differential signal output terminal of the same pair of differential signals of the signal transmission circuit. The operation circuit is electrically connected to each piezoelectric sensor channel circuit, the first voltage reference terminal, and the processor, respectively, for outputting a conditioned voltage signal to the processor. The processor is configured to determine the status of the piezoelectric sensor based on the conditioned voltage signal. Specifically, when the conditioned voltage signal is higher than a preset threshold, the piezoelectric sensor is determined to be in a normal state; when the conditioned voltage signal is lower than the preset threshold, the piezoelectric sensor is determined to be in an abnormal state. When the number of piezoelectric sensors in an abnormal state is lower than a set value, the processor blocks the signals transmitted by the piezoelectric sensors in the abnormal state. Thus, during the production process, it is possible to directly detect whether the piezoelectric sensor has a poor electrical connection, intercepting the poor electrical connection of the piezoelectric sensor in the previous step, avoiding the trouble of subsequent disassembly, and improving production efficiency. If a poor electrical connection is detected on the user side, the processor can be used to shield these poorly connected piezoelectric sensors, ensuring the recognition rate is within a controllable range. This solves the problem of existing smart interactive tablets that require the piezoelectric sensors installed under the inner surface glass of the touch screen to be removed after assembly, which is cumbersome and affects production efficiency.

[0109] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0110] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the present invention as described above. For the sake of simplicity, they are not provided in detail. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that it is still possible to modify the technical solutions described in the above embodiments, or to make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A smart interactive tablet, characterized in that: include: A plurality of piezoelectric sensors arranged in parallel, wherein the plurality of piezoelectric sensors are installed below the glass on the inner surface of the smart interactive flat panel touch screen; a plurality of detection circuit modules corresponding one-to-one to the plurality of piezoelectric sensors; Wherein, the detection circuit module includes: a signal transmission circuit, a piezoelectric sensor channel circuit, an operation circuit, a first voltage reference terminal and a processor; The piezoelectric sensor channel circuit includes a signal isolation circuit, a first access terminal, and a second access terminal; the first access terminal and the second access terminal are used to connect to the piezoelectric sensor; the signal isolation circuit is electrically connected to the output terminal of the signal transmission circuit, and is used to receive the signal transmitted by the signal transmission circuit; the first access terminal is electrically connected to the signal isolation circuit; and the second access terminal is electrically connected to the first voltage reference terminal; The operation circuit is electrically connected to the signal isolation circuit, the first voltage reference terminal and the processor respectively, and is used to output a conditioned voltage signal to the processor; The processor is used to determine the state of the piezoelectric sensor based on the conditioned voltage signal; specifically: when the conditioned voltage signal is higher than a preset threshold, the piezoelectric sensor is determined to be in a normal state; when the conditioned voltage signal is lower than the preset threshold, the piezoelectric sensor is determined to be in an abnormal state, and when the number of the piezoelectric sensors in the abnormal state is lower than a set value, the processor shields the signal transmitted by the piezoelectric sensor in the abnormal state.

2. The smart interactive tablet according to claim 1, characterized in that: The signal transmitting circuit includes at least one GPIO port, which is electrically connected to the signal isolation circuit of the piezoelectric sensor channel circuit and is used to stimulate a short square wave pulse signal to the signal isolation circuit.

3. The smart interactive tablet according to claim 2, characterized in that: The signal isolation circuit includes a transistor and a third resistor, the base of the transistor is electrically connected to the GPIO port, the collector of the transistor is electrically connected to the second reference voltage terminal through the third resistor, and the emitter of the transistor is the first access terminal.

4. The smart interactive tablet according to claim 2, characterized in that: The signal isolation circuit includes a MOS transistor and a fourth resistor. The gate of the MOS transistor is electrically connected to the GPIO port. The drain of the MOS transistor is electrically connected to the second reference voltage terminal through the fourth resistor. The source of the MOS transistor is the first access terminal.

5. The smart interactive tablet according to claim 1, characterized in that: The operational circuit is an operational amplifier circuit, which includes a current limiting circuit and a signal conditioning circuit, wherein: the current limiting circuit is electrically connected to the output end of the signal isolation circuit; the signal conditioning circuit is electrically connected to the current limiting circuit, the first voltage reference end and the processor, respectively, for outputting a conditioned voltage signal to the processor.

6. The smart interactive tablet according to claim 5, characterized in that: The current limiting circuit includes a first resistor, and the first resistor is electrically connected to the output end of the signal isolation circuit.

7. The smart interactive tablet according to claim 5, characterized in that: The signal conditioning circuit includes an operational amplifier and a feedback circuit; the positive input terminal of the operational amplifier is electrically connected to the first voltage reference terminal, and the negative input terminal of the operational amplifier is electrically connected to the current limiting circuit; the output terminal of the operational amplifier is electrically connected to the negative input terminal of the operational amplifier through the feedback circuit, and the output terminal of the operational amplifier is used to output a conditioned voltage signal.

8. The smart interactive tablet according to claim 7, characterized in that: The feedback circuit includes a second resistor and a second capacitor, the second resistor and the second capacitor are connected in parallel, and two connection ends of the second resistor and the second capacitor are electrically connected to the negative input terminal and the output terminal of the operational amplifier respectively.

9. The smart interactive tablet according to claim 3 or 4, characterized in that: The reference voltage of the second reference voltage terminal is greater than the reference voltage of the first reference voltage terminal.

10. A smart interactive tablet, characterized in that: include: A plurality of piezoelectric sensors are installed below the glass on the inner surface of the smart interactive flat panel touch screen; a plurality of detection circuit modules corresponding one-to-one to the plurality of piezoelectric sensors; Wherein, the detection circuit module includes: a signal transmission circuit, a piezoelectric sensor channel circuit, an operation circuit, a first voltage reference terminal and a processor; The signal transmitting circuit includes a plurality of pairs of short square wave pulse differential signals, each pair of short square wave pulse differential signals includes a first differential signal output terminal and a second differential signal output terminal; Each of the piezoelectric sensor channel circuits includes a first access terminal and a second access terminal; the first access terminal and the second access terminal are used to connect to the piezoelectric sensor; the first access terminal and the second access terminal are respectively electrically connected to a first differential signal output terminal and a second differential signal output terminal of a pair of differential signals of the signal transmitting circuit; The operation circuit is electrically connected to each piezoelectric sensor channel circuit, the first voltage reference terminal and the processor, and is used to output a conditioned voltage signal to the processor; The processor is used to determine the state of the piezoelectric sensor based on the conditioned voltage signal; specifically: when the conditioned voltage signal is higher than a preset threshold, the piezoelectric sensor is determined to be in a normal state; when the conditioned voltage signal is lower than the preset threshold, the piezoelectric sensor is determined to be in an abnormal state; when the number of the piezoelectric sensors in the abnormal state is lower than a set value, the processor shields the signals transmitted by the piezoelectric sensors in the abnormal state.

11. The smart interactive tablet according to claim 10, characterized in that: The operational circuit is an operational amplifier circuit, which includes a current limiting circuit and a signal conditioning circuit, wherein: the current limiting circuit is electrically connected to the output end of the signal isolation circuit; the signal conditioning circuit is electrically connected to the current limiting circuit, the first voltage reference end and the processor, respectively, for outputting a conditioned voltage signal to the processor.

12. The smart interactive tablet according to claim 11, characterized in that: The current limiting circuit includes a first resistor, which is electrically connected to the output end of the signal isolation circuit.

13. The smart interactive tablet according to claim 11, characterized in that: The signal conditioning circuit includes an operational amplifier and a feedback circuit; the positive input terminal of the operational amplifier is electrically connected to the first voltage reference terminal, and the negative input terminal of the operational amplifier is electrically connected to the current limiting circuit; the output terminal of the operational amplifier is electrically connected to the negative input terminal of the operational amplifier through the feedback circuit, and the output terminal of the operational amplifier is used to output a conditioned voltage signal.

14. The smart interactive tablet according to claim 13, characterized in that: The feedback circuit includes a second resistor and a second capacitor, the second resistor and the second capacitor are connected in parallel, and two connection ends of the second resistor and the second capacitor are electrically connected to the negative input terminal and the output terminal of the operational amplifier respectively.

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