Infrared touch frame circuit board, infrared touch frame, and infrared touch screen

Abstract

The present disclosure provides an infrared touch frame circuit board, an infrared touch frame, and an infrared touch screen. The specific implementation solution of the infrared touch frame circuit board comprises: the infrared touch frame circuit board comprises a mainboard and a plurality of slave boards; the mainboard is sequentially connected in series with the slave boards by means of a scanning data bus and slave resistors corresponding to the slave boards, and the mainboard is connected to the slave boards by means of a synchronous scanning signal bus; the mainboard is used for determining address information of the slave boards on the basis of the slave resistors corresponding to the slave boards, and delivering, on the basis of the address information, scanning data to the slave boards by means of the scanning data bus; the mainboard is also used for delivering a synchronous scanning signal to the slave boards by means of the synchronous scanning signal bus; and the slave boards are used for receiving the scanning data, and upon reception of the synchronous scanning signal, controlling, on the basis of the scanning data, the infrared lamp tubes in the slave boards to carry out scanning. The use of the technical solution of the present disclosure reduces the connecting pins between the mainboard and the slave boards.

Description

Infrared touch frame circuit board, infrared touch frame and infrared touch screen Technical Field

[0001] The present disclosure relates to the field of display technology, in particular to the field of touch detection, and specifically to an infrared touch frame circuit board, an infrared touch frame, and an infrared touch screen. Background Art

[0002] The infrared touch frame of a large touchscreen can be composed of multiple boards, each of which can house both transmitting and receiving lamps. During scanning, a master MCU controls each board to perform the transmitting or receiving scanning operation. Each board contains logic devices to implement the scanning control logic. However, due to structural factors, the connectors on the boards have a limited number of pins, making it impossible to connect a single master MCU to multiple boards. Summary of the Invention

[0003] The present disclosure provides an infrared touch frame circuit board, an infrared touch frame, and an infrared touch screen.

[0004] According to one aspect of the present disclosure, there is provided an infrared touch frame circuit board, comprising:

[0005] The device comprises a master board and a plurality of slave boards, wherein the master board is connected in series with the slave boards via a scan data bus and slave resistors corresponding to the slave boards, and the master board is connected with the slave boards via a synchronous scan signal bus;

[0006] The master board is configured to determine address information of the slave board based on a slave resistor corresponding to the slave board, and send scan data to the slave board via the scan data bus based on the address information;

[0007] The master board is further configured to send a synchronous scanning signal to each of the slave boards via the synchronous scanning signal bus;

[0008] The slave board is used to receive the scanning data, and when receiving the synchronous scanning signal, controls the infrared lamp in the slave board to perform scanning according to the scanning data.

[0009] According to another aspect of the present disclosure, an infrared touch frame is provided, comprising: the infrared touch frame circuit board according to any one of the embodiments of the present disclosure, and an infrared lamp array connecting a main board and multiple slave boards in the infrared touch frame circuit board.

[0010] According to another aspect of the present disclosure, an infrared touch screen is provided, comprising: a display screen and the infrared touch frame according to any one of the embodiments of the present disclosure, wherein the infrared touch frame is arranged around the display screen.

[0011] According to the technology disclosed in the present invention, the infrared touch frame circuit board includes a main board and multiple slave boards. The main board is connected in series with the slave board through a scan data bus and a slave resistor corresponding to the slave board, and the main board is connected to the slave board through a synchronous scan signal bus. In this way, the main board can determine the address information of the slave board through the slave resistor corresponding to the slave board, and the main board sends corresponding scan data to each slave board through the scan data bus based on the address information of each slave board. Subsequently, the main board can send a synchronous scan signal to each slave board through the synchronous scan signal bus, so that each slave board responds to the synchronous scan signal synchronously, and controls the infrared lamp in the slave board to perform scanning according to the corresponding scan data. Moreover, the connection line between the main board and each slave board is simple, and it does not need to occupy too many pins of the main board, and the scan data can be accurately sent to each slave board, so that synchronous scanning can be achieved by sending a synchronous scan signal only through a synchronous scan signal bus.

[0012] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are provided to facilitate a better understanding of the present invention and do not constitute a limitation of the present disclosure.

[0014] FIG1 is a schematic diagram of an infrared touch frame circuit board according to an embodiment of the present disclosure;

[0015] FIG2 is a schematic diagram of an infrared touch frame circuit board according to another embodiment of the present disclosure;

[0016] FIG3 is a schematic diagram of an infrared touch frame circuit board according to another embodiment of the present disclosure;

[0017] FIG4 is a schematic diagram of a PWM synchronous scanning signal according to an embodiment of the present disclosure;

[0018] FIG5 is a schematic diagram of an infrared touch frame structure according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0019] The following description of exemplary embodiments of the present disclosure is made in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be appreciated by those skilled in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope of the present disclosure. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0020] Those skilled in the art will understand that, unless otherwise stated, the singular forms "a," "an," "the," and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of this application refers to the presence of the stated features, integers, steps, and operations, but does not preclude the presence or addition of one or more other features, integers, steps, and operations.

[0021] Fig. 1 is a schematic diagram of an infrared touch frame circuit board according to one embodiment of the present disclosure. Fig. 2 is a schematic diagram of an infrared touch frame circuit board according to another embodiment of the present disclosure.

[0022] As shown in Figure 1, in the infrared touch frame, multiple pairs of infrared tubes are arranged around the perimeter, while numerous infrared emitting and / or receiving tubes are distributed on boards that are spliced ​​end to end. Due to the limited length of a single PCB, the boards are connected via connectors, forming a longer side. The multiple boards serve as a master board and multiple slave boards, respectively. If a board only has an array of infrared emitting tubes, it is generally called an infrared emitting board; if a board only has an array of infrared receiving tubes, it is generally called an infrared receiving board. In some cases, a single board may have both infrared emitting and receiving tubes, depending on the overall technical solution. As shown in Figure 2, each board uses a shift register and decoder to control the row and column matrix of infrared emitting, receiving, and / or receiving tubes. Control of the shift register and decoder enables precise control of each infrared emitting or receiving tube. Then, the infrared signal received by the infrared receiving lamp is sampled, and whether there is an object blocking the infrared light is determined based on whether the adjusted and stabilized signal has changed. In this way, the touch operation is judged and the corresponding position coordinates are output, thereby realizing the touch, writing and other functions of the infrared touch frame.

[0023] As shown in Figure 2, each board typically has 6 to 8 columns of infrared emitting lamps and / or infrared receiving lamps. Each column requires a pin for control, and pins for reset and other functions are also required. Figure 1 shows the connection between boards. Since each board is connected via connectors, if the control pins and other functional pins for the infrared emitting lamps, infrared receiving lamps, and / or infrared receiving lamp arrays were all directly controlled by the microprocessor (MCU), the number of connector pins would be insufficient. As shown in Figure 2, for each board in the infrared touch panel, the control circuit controls the shift register and decoder through a controller. The shift register's Q0, Q1, ..., Qn signals serve as row control signals, using the serial bus CLK (clock signal), DATA (data signal), and MR (clear signal). The decoder, acting as a column control chip, uses Y0, Y1, ..., Yn signals as column control signals, using parallel lines A0, A1, and A2 (address lines) and EN (enable line). This reduces the total number of control lines from the microprocessor (MCU) to each board, thereby meeting the requirements for the number of pins required for the connection terminals. Since each board must be equipped with both a shift register and a decoder, reducing the number of pins required for the connection terminals between boards to meet existing connection terminal requirements is costly and complex to control.

[0024] FIG3 is a schematic diagram of an infrared touch frame circuit board according to another embodiment of the present disclosure.

[0025] As shown in Figure 3, the infrared touch frame circuit board includes a main board and multiple slave boards. The example in the figure includes slave boards ① to ⑦. A plurality of infrared lamps are provided on the main board and each slave board. The infrared lamps can be infrared transmitting tubes and / or infrared receiving tubes. The main board is connected in series with the slave board through the scanning data bus and the slave resistor corresponding to the slave board. For example, a scanning data bus is set, the main board is connected to the scanning data bus, and each slave board is connected to the scanning data bus through the slave resistor. Exemplarily, the scanning data bus can be an IIC (Inter-Integrated Circuit) data signal bus, which can transmit IIC signals.

[0026] The slave resistors corresponding to the slave boards are different from each other, so that the slave resistors are actually used to identify the address information of the slave boards.

[0027] At the same time, the master board is also connected to each slave board via a synchronous scanning signal bus to transmit synchronous scanning signals to each slave board. For example, a synchronous scanning signal bus is set up, the master board is connected to the synchronous scanning signal bus, and each slave board is also connected to the synchronous scanning signal bus.

[0028] The host board can be connected to the slave board as a separate circuit board, or it can be integrated into any slave board and share a circuit board card with the slave board. If the host board is a separate circuit board card, the infrared lamp can be omitted.

[0029] During operation of the infrared touch frame circuit board, the main board determines the address information of each slave board based on its corresponding slave resistor. Based on this address information, the main board sends corresponding scan data to each slave board via the scan data bus. The main board then sends synchronous scan signals to each slave board via the synchronous scan signal bus. The slave board receives the scan data and, upon receiving the synchronous scan signal, controls the infrared lamps in the slave board to scan based on the scan data to obtain touch data.

[0030] The master board may send the scan data corresponding to each slave board to each slave board in sequence.

[0031] In this embodiment, before scanning begins, the master board sends corresponding scanning data to each slave board via the scan data bus and the slave motor group of each slave board. Each slave board receives and stores its own scan data. When performing infrared lamp scanning, each slave board reads the scan data and performs scanning based on the scan data. Typically, the scan data includes the position information of the infrared receiving and transmitting lamps in the slave board, as well as the corresponding scanning logic.

[0032] After scanning begins, the master board sends a synchronous scanning signal to each slave board via the synchronous scanning data bus, triggering each slave board to control the infrared lamps in the slave board to scan based on its stored scanning data. Specifically, after receiving the synchronous scanning signal from the master board, the slave board triggers the scanning process based on the synchronous scanning signal. The slave board reads its stored scanning data and, after preparations are complete, controls the operating status of its connected infrared receiving and transmitting diodes based on the synchronous scanning signal.

[0033] According to the above embodiment, the master board is connected to each slave board via different pull-up resistors. This simplifies the connection circuitry and eliminates the need to occupy excessive pins on the master board, allowing accurate distribution of scan data to each slave board. Subsequently, a single synchronous scan signal line transmits a synchronous scan signal to each slave board, enabling synchronized scanning. The small amount of synchronous scan signal data ensures scanning speed while also ensuring precise scanning control for each slave board. Consequently, after scanning begins, the master board does not need to send different scan data for each slave board's different scanning conditions. This reduces the workload on the master board and avoids excessive amounts of scan control signal data transmitted between the master and slave boards during scanning, thus meeting high-speed scanning requirements.

[0034] In some embodiments, each slave board can send its acquired touch data to the master board via a scanning data bus. The master board then calculates the coordinates of the touch object based on the touch data provided by each slave board. In some embodiments, the touch data can be an analog signal. The master board converts the analog signal into a digital signal and then calculates the digital signal to obtain the coordinates of the touch object.

[0035] In some embodiments, the synchronous scanning signal can be an analog signal. After scanning begins, the slave board loads the analog electrical signal output by the infrared lamps receiving the infrared light signal onto the analog signal bus. If the synchronous scanning signal is transmitted using a digital signal, the touch data transmitted on the scan data bus will significantly interfere with the infrared light signal received by the infrared lamps and transmitted on the synchronous scanning signal bus. Because the synchronous scanning signal and the infrared signal received by the infrared lamps may be transmitted at the same time, interference cannot be avoided by adjusting the timing. Therefore, using an analog signal bus to transmit the synchronous scanning signal between the master board and the slave board can avoid interference.

[0036] In some embodiments, before scanning begins, the master board may further verify the scan data with the slave board via the scan data bus.

[0037] When the mainboard is powered on, it verifies the scan data with the slave boards via the scan data bus. If the verification passes, the current slave board's scan data is available. The slave board reads the scan data and completes scan preparation. The mainboard then sends a synchronous scan signal via the synchronous scan signal bus to trigger each slave board to execute the scan process synchronously. If the verification fails, the mainboard resends the corresponding scan data to the slave board via the scan data bus. The slave board receives the scan data and completes scan preparation. The mainboard then sends a synchronous scan signal to trigger each slave board to execute the scan process synchronously.

[0038] For example, at the time of shipment, the master board has already sent scan data to the slave boards. Each subsequent time the system is powered on, the master board verifies the data with the slave boards via the scan data bus. If the scan data from the slave board is normal, the master board determines that the slave board's scan data is valid. If the verified scan data is abnormal, the master board resends the scan data to the slave board. Furthermore, after each slave board completes a firmware upgrade, the master board also needs to resend scan data to each slave board, which then receives and stores the scan data.

[0039] As in the solution of the above embodiment, the availability of the scan data can be ensured through the verification process, so that the slave board can be in a normal working state when performing the scan, thereby avoiding scan failure.

[0040] In some embodiments, the synchronous scanning signal used by the master board can be a PWM signal. The PWM signal includes a synchronous scanning start signal and a PWM pulse signal. This allows each slave board to synchronously trigger a scanning process starting from the start signal. The pulse width of the start signal is different from the pulse width of the PWM pulse signal.

[0041] The main board sends a PWM signal to each slave board. Each slave board receives the PWM signal and, in response to the start signal in the PWM signal, synchronously triggers each slave board to start controlling the infrared transmitting tube in the slave board to transmit signals or the infrared receiving tube to receive signals based on the PWM pulse signal in the PWM signal and the corresponding scanning data.

[0042] In some embodiments, a buffered time interval is set between the start signal and the PWM pulse signal.

[0043] Refer to Figure 4, which is a schematic diagram of an example PWM synchronous scanning signal, in which the pulse width of the start signal is different from the PWM pulse width of the switch lamp (infrared lamp tube). As shown in the figure, the pulse width of the start signal is τ1, the PWM pulse width of the switch lamp is τ2, and the time interval between the two is τ3. The time interval τ3 is used to wait for the slave board to complete the start signal analysis and complete the buffer time for the scan data preparation, thereby facilitating the synchronous start of the scan control of each slave host. Among them, τ1, τ2, and τ3 are the set time widths. As shown in the example of Figure 4, τ1 = 4us, τ2 = 0.5us, and τ3 = 59.35us; after the main board transmits the PWM synchronous scanning signal to the slave host, the slave host parses the data of the PWM synchronous scanning signal in real time and starts a frame scan when the start signal is recognized.

[0044] As in the above embodiment, if there is no start signal, the synchronous scanning signal cannot be correctly parsed when the slave board is hot-plugged. With the start signal, each frame of the signal can be accurately parsed regardless of whether the slave board is offline. All slave boards will use the start signal of the synchronous scanning signal as a reference for subsequent data parsing.

[0045] In one embodiment, the main board transmits a synchronous scanning signal to the slave board via an analog signal bus. The synchronous scanning signal can be a low voltage difference or low current signal. The main board first attenuates the synchronous scanning signal and then transmits the attenuated synchronous scanning signal to the slave board; the slave board receives the attenuated synchronous scanning signal and amplifies and restores it.

[0046] For example, since the synchronous scanning signal adopts a PWM synchronous scanning signal, and in order to ensure that the PWM synchronous scanning signal is transmitted using an analog signal bus during the scanning process to avoid affecting the analog signal generated by the infrared light received by the infrared lamp, the PWM synchronous scanning signal output by the main board can be first attenuated or converted into a signal suitable for analog signal bus transmission on the main board, and then transmitted to the slave board through the analog signal bus, and then amplified or converted on the slave board before use.

[0047] As in the solution of the above embodiment, by attenuation and amplification processing, the influence of the PWM synchronous scanning signal as a strong digital signal on the analog signal is avoided, and the stability of transmission can be improved.

[0048] In order to make the hardware structure of the host board and the slave board of the infrared touch frame circuit board of the present application clearer, several embodiments are described below.

[0049] In one embodiment, a main board is provided with a signal conditioning circuit, an A / D sampling circuit and a main MCU connected in sequence; wherein the signal conditioning circuit is connected to an analog signal bus, and the main MCU is also connected to the digital signal bus; further, the signal conditioning circuit is used to detect an analog electrical signal from the analog signal bus and amplify and condition it; the A / D sampling circuit is used to perform A / D sampling on the amplified analog electrical signal to obtain a digital signal, and transmit it to the main MCU through a set protocol.

[0050] In some embodiments, for a scheme in which the master board controls the operating state of the slave boards, the master board is configured to send corresponding scan data to each slave board based on the address information of each slave board, thereby setting at least one slave board to a receiving state and setting other slave boards on a different side of the receiving slave board to a transmitting state. In this manner, at any given moment, on the same side of the infrared touch frame, only one slave board is set to a receiving state, while the other slave boards are set to a transmitting state or to a state in which neither transmits nor receives. If a slave board is located on the same side as a slave board selected as a receiving board, the slave board neither transmits nor receives during its receiving cycle.

[0051] In some embodiments, the receiving state means that at least one infrared receiving tube in the corresponding slave board is in a state where it is allowed to operate (allowed to be connected state), and all infrared transmitting tubes in the corresponding slave board are in a state where it is prohibited to operate (disabled to transmit state). The transmitting state means that all infrared receiving tubes in the corresponding slave board are in a state where it is prohibited to operate (disabled to be connected state), and at least one infrared transmitting tube in the corresponding slave board is in a state where it is allowed to operate (allowed to transmit state).

[0052] Because the slave boards are connected to both infrared transmitters and receivers, each can both transmit and receive infrared light signals. Therefore, the master board can scan data to set one slave board to receive mode. At the same time, it can also set another slave board to transmit mode while the others are in a non-transmitting or non-receiving state. For group scanning, multiple infrared receivers are activated in groups to receive simultaneously. The infrared receivers on each slave board are then periodically controlled to scan the infrared light signals. This allows for cross-axis scanning, where infrared light is distributed from the X-axis to the Y-axis, resulting in a more uniform distribution of light and higher precision.

[0053] For example, in the circuit board structure shown in Figure 3, starting with slave board 1, slave board 1 is set to the receiving state. Then, slave boards 2 through 7 are sequentially set to the transmitting state, and the infrared emitting diodes on these boards transmit in sequence. During the period when slave board 1 is in the receiving state, if slave board 8 is integrated into the main board, since slave board 8 is located on the same side as slave board 1, it neither transmits nor receives. After the infrared receiving diode connected to slave board 1 is scanned, slave board 2 is selected and set to the receiving state, and the other slave boards are sequentially set to the transmitting state. This cycle continues, scanning the infrared receiving diodes periodically.

[0054] In one embodiment, the main board can transmit scanning data to each slave board, set at least one infrared receiving tube connected to one of the receiving boards to the on state (a state that allows work), and set at least one infrared transmitting tube connected to one of the transmitting boards to the transmitting state (a state that allows work).

[0055] Specifically, an infrared transmitting tube or an infrared receiving tube is connected to the slave board, and scanning data is sent to each slave board through the main board to control its working state. One of the slave receiving boards is set to the receiving state, and the infrared receiving tube connected to it can be controlled to receive infrared light signals. At the same time, according to the scanning requirements, at least one slave board is set to the transmitting state, and the infrared transmitting tube connected to it can be controlled to emit infrared light signals, thereby realizing a non-cross-axis scanning mode. At this time, there is no infrared light from the X-axis to the Y-axis in the infrared touch frame.

[0056] For example, in the circuit board structure shown in Figure 3, assuming that slave boards ②, ③, ④, and ⑤ are transmitting boards, and slave boards ⑥, ⑦, ⑧ (integrated into the main board), and ① are receiving boards, any receiving board can be set to a receiving state according to the scanning sequence and start scanning in sequence. At the same time, the corresponding transmitting board can be set to a transmitting state to control some or all infrared transmitting tubes to transmit infrared light signals. In this way, the infrared receiving tubes are scanned periodically.

[0057] In one embodiment, when controlling the operating states of the slave boards, the master board can transmit a synchronous scanning signal to each slave board to place at least one slave board in a receiving state and the other slave boards in a transmitting state. At the same time, at least one slave board is placed in a receiving state and another slave board is placed in a transmitting state, while the other slave boards are placed in a non-transmitting and non-receiving state. If a slave board is located on the same edge as a slave board selected as a receiving board, the slave board neither transmits nor receives during the receiving cycle of the receiving board.

[0058] For example, in the circuit board structure shown in Figure 3, assume that at a certain moment, the infrared receiver tube group (composed of multiple infrared receiver tubes) is distributed across slave boards ② and ③. At this time, slave boards ①, ⑧, ⑦, ⑥, ⑤, and ④ are sequentially set to the transmitting state. The infrared receiver tubes of the infrared receiver tube group are arranged across the slave boards, allowing for more flexible lighting layout, without being restricted to the number of infrared receiver tubes being an integer multiple of the sampling channels.

[0059] According to the technology disclosed in the present invention, the infrared touch frame circuit board includes a main board and multiple slave boards. The main board is connected in series with the slave board through a scan data bus and a slave resistor corresponding to the slave board, and the main board is connected to the slave board through a synchronous scan signal bus. In this way, the main board can determine the address information of the slave board through the slave resistor corresponding to the slave board, and the main board sends corresponding scan data to each slave board through the scan data bus based on the address information of each slave board. Subsequently, the main board can send a synchronous scan signal to each slave board through the synchronous scan signal bus, so that each slave board responds to the synchronous scan signal synchronously, and controls the infrared lamp in the slave board to perform scanning according to the corresponding scan data. Moreover, the connection line between the main board and each slave board is simple, and it does not need to occupy too many pins of the main board, and the scan data can be accurately sent to each slave board, so that synchronous scanning can be achieved by sending a synchronous scan signal only through a synchronous scan signal bus.

[0060] In one embodiment, based on the hardware structure of the host board and the slave board of the infrared touch frame circuit board of each embodiment above, the control logic for signal transmission between the master MCU and the slave MCU may specifically include the following:

[0061] During initial use, the master MCU initializes the complete scan data when it is powered on, and reads the address of each online slave MCU through the pull-up resistor of each online slave MCU pulled up to the scan data bus (IIC bus). Then, the scan data is sent to each slave MCU through the scan data bus. The scan data is used to provide the slave MCU with relevant data and related scan logic for controlling infrared emission and reception scanning, and the slave MCU saves the corresponding scan data. When the slave MCU receives the synchronous scan signal from the master MCU, it calls the corresponding scan data to control the infrared emission tube of the slave board to transmit or control the infrared receiving tube to perform synchronous scanning. For example, when the slave MCU is produced or the scan data is updated, the master MCU can accurately identify the address of each slave MUC through the pull-up resistor of each slave MCU on the scan data bus, so as to accurately send the corresponding scan data to the corresponding slave MCU.

[0062] In daily use, when the system is powered on, the master MCU first reads the checksum calculated by the slave MCU through the digital signal bus and performs a checksum. Since the infrared lamps controlled by each slave board are located in different positions, their scanning tasks are also different. Therefore, when the main board is powered on, the master MCU uses IIC communication to check with the slave MCU to determine whether the scanning data of each slave board is normal. If it is abnormal, such as the lack of scanning data in the slave MCU, the master MCU sends the scanning data to the slave MCU of the corresponding slave board. After receiving the scanning data, the slave MCU saves it. If the scanning data is normal, it is ready to start scanning. The slave MCU controls the infrared receiving tube or infrared transmitting tube on the slave board based on the scanning data and the synchronous scanning signal.

[0063] For example, each time the power is turned on, the master MCU will verify the scan data bus with the slave MCU. If the scan data on the slave MCU is normal, the master MCU will not send the scan data to the slave MCU. If the scan data is abnormal, the master MCU will resend the scan data to the slave MCU; or after each slave MCU completes the firmware upgrade, the master MCU will resend the scan data to the slave MCU.

[0064] The scanning process is driven by the master MCU, which controls the scanning of each slave MCU through the synchronous scanning signal. The synchronous scanning signal can adopt PWM synchronous scanning signal. The slave MCU performs GPIO output according to the PWM synchronous scanning signal and scanning data, and selects the infrared transmitting tube for transmission or the infrared receiving tube for reception based on this.

[0065] Before scanning begins, the master MCU first performs a check, or sends corresponding scanning data to each slave MCU via the scan data bus and pull-up resistors. The scanning data includes the position information of the infrared receiver and infrared transmitter connected to the slave MCU, as well as the corresponding scanning logic. After receiving the synchronous scanning signal sent by the master MCU, the slave MCU begins scanning control based on the synchronous scanning signal and scanning data. The slave MCU interprets the control information of the synchronous scanning signal and controls the connected infrared receiver and infrared transmitter to operate at the appropriate timing.

[0066] After the scan starts, the master MCU only needs to send a PWM synchronous scan signal to each slave MCU to complete the scan control. The synchronous scan signal has a small amount of data, which ensures the scanning speed while also ensuring accurate scanning control of each slave MCU. For example, after the scan starts, the master MCU does not need to send different scan data and corresponding scan control signals for different scanning conditions of each slave MCU, which reduces the workload of the master MCU and the amount of scan control signal data communicated between the master MCU and the slave MCU during scanning, thereby achieving high-speed scanning.

[0067] For the analysis and processing of PWM synchronous scanning signals, the MCU receives the PWM synchronous scanning signal sent by the main MCU, first determines the pulse width τ1 to identify the start signal, and after determining the start signal, counts the buffer time interval τ3 set between the start signal and the PWM pulse signal. After the MCU determines the PWM pulse signal, it starts scanning control according to the prepared scanning data, parses the control information of the infrared receiving tube and the infrared transmitting tube, and executes the scanning task until a scanning cycle ends.

[0068] As in the solution of the above embodiment, the master MCU is connected to each slave MCU only through an IIC bus and different pull-up resistors. The connection line is simple and does not occupy too many pins of the master MCU, which means that the scanning data can be accurately distributed to each slave MCU. In this way, the synchronous scanning signal is subsequently sent to each slave MCU through a synchronous scanning signal line, and each slave MCU can achieve synchronous scanning. The use of a simple control method achieves complex scanning purposes, with high reliability and fast scanning speed. At the same time, the use of logic devices is reduced, and the function of controlling the scanning status of the transmitting lamp and the receiving lamp on a single slave board can be implemented on a single MCU, which has high reliability. All slave boards can be driven to perform synchronous scanning through a PWM synchronous scanning signal, avoiding complex control logic.

[0069] An embodiment of the infrared touch frame is described below.

[0070] The infrared touch frame provided in this application primarily comprises the infrared touch frame circuit board of any of the aforementioned embodiments, and an infrared lamp array connecting the master board and the slave board. As shown in Figure 5, which is a schematic diagram of an exemplary infrared touch frame structure, partially illustrates the structure. In the structure illustrated in the figure, the infrared lamp array comprises an infrared emitting tube array and an infrared receiving tube array, with the infrared emitting tubes and the infrared receiving tubes arranged in an alternate arrangement.

[0071] When in use, the main board can put the slave board connected to one of the slave boards into the receiving state through polling, and put the other slave boards into the transmitting state in turn; using the group scanning method, taking slave board ⑧ as an example, the slave board ⑧ is put into the receiving state. At this time, the upper side (slave board ④ and slave board ⑤), the left side (slave board ⑥ and slave board ⑦) and the right side (slave board ② and slave board ③) are put into the transmitting state in turn. Each slave board is connected to k = 20 infrared transmitting tubes and k = 20 infrared receiving tubes; the corresponding infrared receiving tubes are numbered 1 to 20, and the sampling rate is 100%. Using 5 infrared receiving tubes as a group for scanning, the analog signal bus has 5 signal channels (i.e., 5 independent buses). First, turn on the infrared receiving tubes numbered 1, 2, 3, 4, and 5 to receive the infrared light signal and output 5 analog electrical signals to the analog signal bus for transmission to the main board. Next, turn on the infrared receiving tubes numbered 6, 7, 8, 9, and 10, and so on, to complete the scanning of 20 infrared receiving tubes. Then select slave board ① as the receiving state and use the same method to scan all 20 infrared receiving tubes. The infrared receiving tubes are scanned periodically in this cycle.

[0072] The infrared touch frame of the above embodiment simplifies the circuit processing flow, has a fast response speed, and improves the frame rate of infrared scanning. Through the transmission of scanning data and the synchronous scanning signal control mechanism, it can avoid the excessive amount of scanning control signal data transmitted between the host board and the slave board during scanning, thereby meeting the requirements of high-speed scanning.

[0073] An embodiment of an infrared touch screen is described below.

[0074] The infrared touch screen provided in the present application is shown in Figure 5, which is a schematic diagram of an example infrared touch screen structure. The figure shows a partial structure, which mainly includes a display screen and an infrared touch frame arranged around the display screen. It can be used on various terminal devices. The display screen can display the picture content. At the same time, the infrared touch frame has a touch positioning function, so that the terminal device used can have a touch function.

[0075] The infrared touch screen of the above embodiment simplifies the circuit processing flow, has a fast response speed, and improves the frame rate of infrared scanning. Through the transmission of scanning data and the synchronous scanning signal control mechanism, it can avoid the excessive amount of scanning control signal data transmitted between the host board and the slave board during scanning, thereby meeting the requirements of high-speed scanning.

[0076] The electronic device as in the above embodiment can be various tablet terminals, such as educational tablet terminals, conference tablet terminals and other tablet terminals, etc.; due to the use of the infrared touch screen of the above embodiment, it can have better touch performance.

[0077] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0078] The above description is only part of the implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An infrared touch frame circuit board, characterized in that: The device comprises a master board and a plurality of slave boards, wherein the master board is connected in series with the slave boards via a scan data bus and slave resistors corresponding to the slave boards, and the master board is connected with the slave boards via a synchronous scan signal bus; The master board is configured to determine address information of the slave board based on a slave resistor corresponding to the slave board, and send scan data to the slave board via the scan data bus based on the address information; The master board is further configured to send a synchronous scanning signal to each of the slave boards via the synchronous scanning signal bus; The slave board is used to receive the scanning data, and when receiving the synchronous scanning signal, controls the infrared lamp in the slave board to perform scanning according to the scanning data.

2. The infrared touch frame circuit board according to claim 1, characterized in that: The synchronous scanning signal is a PWM signal; wherein the PWM signal is provided with a synchronous scanning start signal and a PWM pulse signal, and the pulse width of the start signal is different from the pulse width of the PWM pulse signal; The master board is used to send the PWM signal to each slave board, and each slave board is used to receive the PWM signal. Based on the start signal in the PWM signal, the master board is synchronously triggered to start controlling the infrared transmitting tube in the slave board to transmit signals or control the infrared receiving tube to receive signals based on the PWM pulse signal in the PWM signal and the corresponding scanning data.

3. The infrared touch frame circuit board according to claim 2, characterized in that: A buffer time interval is set between the start signal and the PWM pulse signal.

4. The infrared touch frame circuit board according to claim 1, characterized in that: The master board is configured to send the corresponding scan data to each of the slave boards based on the address information of each of the slave boards, so as to set at least one of the slave boards to a receiving state, and to set the other slave boards that are not on the same side as the slave board in the receiving state to a transmitting state.

5. The infrared touch frame circuit board according to claim 4, characterized in that: The receiving state is that at least one infrared receiving tube in the corresponding slave board is in a state where it is allowed to work, and all infrared transmitting tubes in the corresponding slave board are in a state where it is prohibited to work; The emission state is a state in which all infrared receiving tubes in the corresponding slave board are in a prohibited operation state, and at least one infrared emitting tube in the corresponding slave board is in a permitted operation state.

6. The infrared touch frame circuit board according to claim 1, characterized in that: The slave board is further configured to load the touch data obtained from the scanning operation into the scan data bus, so that the touch data is transmitted to the master board; The main board is further configured to calculate the coordinate position of the touch object based on the touch data provided by each of the slave boards.

7. The infrared touch frame circuit board according to claim 1, characterized in that: The main board is configured to verify the scan data with each of the slave boards via the scan data bus based on the address information of each of the slave boards when the main board is powered on; The host board is further configured to resend the corresponding scan data to the slave board that failed verification via the scan data bus when any of the slave boards fails verification.

8. The infrared touch frame circuit board according to any one of claims 1 to 7, characterized in that: The slave resistors corresponding to the slave boards are different.

9. An infrared touch frame, characterized in that: include: The infrared touch frame circuit board according to any one of claims 1 to 8, and an infrared lamp array connecting a main board and multiple slave boards in the infrared touch frame circuit board.

10. An infrared touch screen, characterized in that: The device comprises a display screen and the infrared touch frame according to claim 9, wherein the infrared touch frame is arranged around the display screen.

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