WO2018214379A1

WO2018214379A1 - Smart tablet with capacitive touch screen

Info

Publication number: WO2018214379A1
Application number: PCT/CN2017/104992
Authority: WO
Inventors: 马正; 邬营杰; 刘天保; 陶炳俊
Original assignee: 广州视源电子科技股份有限公司; 广州视睿电子科技有限公司
Priority date: 2017-05-26
Filing date: 2017-09-30
Publication date: 2018-11-29
Also published as: CN107168467A

Abstract

Disclosed is a smart tablet (100) with a capacitive touch screen. The smart tablet comprises: a complete machine (10), a capacitive touch screen (20), a liquid crystal display panel (30) and an isolator (40), wherein the liquid crystal display panel (30) is arranged between the complete machine (10) and the capacitive touch screen (20); the complete machine (10) comprises a power source (11), a TV main board (12), a capacitive touch screen control board (13) and a liquid crystal screen drive board (14); the power source (11) is connected to the TV main board (12); the liquid crystal screen drive board (14) is connected to the liquid crystal display panel (30) and the TV main board (12); the capacitive touch screen control board (13) is connected to the capacitive touch screen (20); and the capacitive touch screen control board (13) is provided with a first interface, the TV main board (12) is provided with a second interface, and the first interface is connected to the second interface by means of the isolator (40). By means of adding the isolator (40) to isolate the complete machine (10) from the capacitive touch screen (20), the grounding interference suffered by the complete machine (10) cannot be transferred to the capacitive touch screen (20), thus ensuring stable operation of the capacitive touch screen (20).

Description

Capacitive screen smart tablet

Technical field

The invention relates to the field of smart tablets, in particular to a capacitive screen smart tablet.

Background technique

The smart tablet is an integrated device that controls the content displayed on the display tablet through touch technology to realize human-computer interaction. The smart tablet integrates various functions of projector, electronic whiteboard, curtain, audio, TV, video conferencing terminal, and is suitable for group communication occasions. It solves the problem of remote audio and video communication in conferences and high-definition display of conference documents in various formats. Systematic meeting requirements such as video file playback, live audio, screen writing, document labeling, saving, printing and distribution are widely used in education, business meetings, business presentations, etc., which can effectively improve the communication environment and improve group communication efficiency.

Currently, the commonly used smart tablets can be roughly classified into an infrared screen smart tablet and a capacitive screen smart tablet according to the type of touch. Infrared Touch Screen Technology consists of a touch screen and infrared transmitting and receiving sensing elements mounted on the outer frame of the touch screen. The infrared emitting and receiving sensing elements form an infrared detecting net on the surface of the screen, and any touch object can change the contact. Touch screen operation is achieved by infrared rays. The capacitive screen works with the current sensing of the human body. The advantage of the infrared touch screen is that it is cheap and free from current, voltage and static interference, and is suitable for harsh environmental conditions. The disadvantage is that the resolution is low, and the thickness of the whole machine is increased due to the increase of the outer frame. The advantage of the capacitive screen is that the writing experience is smooth, the resolution is high, and the whole machine can be made thin, but the disadvantage of the capacitive screen is that it is easily disturbed by the interference of the external environment, resulting in inaccurate touch or inability to touch and write. For example, when the ambient temperature and humidity change, it will cause the capacitive screen to drift, resulting in inaccurate touch. The drift of the capacitive screen is a technically insufficiency. The environmental potential surface (including the user's body) is farther away from the capacitive touch screen, but much larger than the finger area. These factors directly affect the determination of the touch position.

Summary of the invention

However, the inventor found in the process of applying a capacitive screen to a smart tablet, especially a large-sized smart tablet, even if the influence of external environmental interference is eliminated, the capacitive screen may still have a jump point or a written interruption, and this phenomenon There are no reasonable explanations for the reasons at present. The inventor discovered through further research that the main reason for this jump point is that the noise signal of the external power grid and the liquid crystal display panel and the whole machine will interfere with the grounding of the whole machine during operation, because the whole machine and the capacitive screen perform USB. Communication and the need to supply power to the capacitive screen, the grounding of the whole machine and the grounding of the capacitive screen need to be connected, which causes the interference of the grounding of the whole machine to be conducted to the grounding of the capacitive screen, and the capacitive screen needs to be grounded by its own ground. Therefore, when the grounding is disturbed, it may cause a change in the reference, resulting in a capacitive screen jump point.

In view of the above problems, an object of the present invention is to provide a capacitive screen smart panel, which can avoid the interference of the whole machine to the grounding of the capacitive screen, and solve the jumping point phenomenon caused by the interference of the capacitive screen.

The invention provides a capacitive screen smart panel, comprising: a whole machine, a capacitive screen, a liquid crystal display panel and an isolator, wherein the liquid crystal display panel is disposed between the whole machine and the capacitive screen; wherein, the whole The device includes a power source, a TV motherboard, a capacitive screen control panel, and a liquid crystal panel driving board; the power source is connected to the TV motherboard; the LCD panel driving board is connected to the liquid crystal display panel and the TV motherboard, and the capacitive screen The control panel is connected to the capacitive screen; the capacitive screen control panel has a first interface, the TV motherboard has a second interface, and the first interface and the second interface are connected by the isolator.

Preferably, the isolator has a signal isolation function.

Preferably, the isolator has both a power isolation function and a signal isolation function.

Preferably, the first interface and the second interface are USB interfaces, and the isolator is a USB isolator.

Preferably, the first interface and the second interface are USB2.0 interfaces.

Preferably, the first interface and the second interface are USB3.0 interfaces.

Preferably, the first interface and the second interface are interfaces based on a VB1 protocol.

Preferably, the first interface and the second interface are interfaces based on a UART protocol.

Preferably, the first interface and the second interface are interfaces based on an SPI protocol.

Preferably, the first interface and the second interface are COM ports.

Preferably, the first interface and the second interface are interfaces based on an I2C protocol.

Preferably, the capacitive screen smart tablet further includes an AD conversion module; the capacitive screen is connected to the capacitive screen control board through a capacitive screen receiving line and a capacitive screen output line, and the AD conversion module is connected to the capacitive screen to receive on-line.

Preferably, the AD conversion module is disposed at one end of the capacitive screen receiving line connected to the capacitive screen.

Preferably, the whole machine further includes a whole machine backplane, the capacitive screen control board is hung on the whole machine backboard; the capacitive screen receiving line and the capacitive screen output line are controlled from the capacitive screen The board is led out and connected to the capacitive screen body along the inner wall of the whole backplane; wherein the capacitor receiving line and the capacitor output line have a conductor layer and a first insulation covering the conductor layer And a shielding layer covering the first insulating layer, and the shielding layer is insulated from the inner wall of the whole backing plate.

Preferably, the shielding layer is provided with a second insulating layer surrounding the shielding layer; or

An insulating spacer is interposed between the shielding layer and an inner wall of the whole machine backboard; or

An insulating tape is attached to a portion of the inner wall of the whole machine back plate that is in contact with the shielding layer.

Preferably, a power isolator is further included, and the power source is connected to the capacitive screen control board through the power isolator.

The capacitive screen smart tablet provided by the embodiment of the present invention, by adding the isolator between the TV main board and the capacitive screen control board, so that the interference received by the grounding end of the whole machine is not transmitted to the The grounding end of the capacitive screen further avoids the phenomenon that the capacitive screen is caused by the interference of the whole machine, which improves the working stability of the capacitive screen.

DRAWINGS

In order to more clearly illustrate the technical solution of the present invention, the following needs to be used in the embodiment. BRIEF DESCRIPTION OF THE DRAWINGS The drawings in the following description are merely illustrative of the embodiments of the present invention, and may be obtained by those skilled in the art without the Other drawings.

FIG. 1 is a schematic structural diagram of a capacitive screen smart tablet according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a connection of a whole machine according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of the whole machine and the capacitive screen isolated by the isolator according to the embodiment of the present invention.

FIG. 4 is a schematic diagram of a connection between interfaces based on a VB1 protocol according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of a connection between interfaces based on a UART protocol according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of a connection between interfaces based on an SPI protocol according to an embodiment of the present invention.

FIG. 7 is a schematic diagram of an RS232 interface according to an embodiment of the present invention.

Figure 8 is a pin definition diagram of the RS232 interface of Figure 7.

Figure 9 is a pin definition diagram of the RS422 interface.

Figure 10 is the first pin definition of the RS485 interface.

Figure 11 is a second pin definition of the RS485 interface.

FIG. 12 is a schematic diagram of a connection between interfaces based on an I2C protocol according to an embodiment of the present invention.

FIG. 13 is a schematic diagram of another connection between a whole machine and a capacitive screen according to an embodiment of the present invention.

FIG. 14 is a schematic cross-sectional view of a capacitive screen receiving according to an embodiment of the present invention.

FIG. 15 is another schematic diagram of a connection between a whole machine and a capacitive screen according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Referring to FIG. 1 to FIG. 3 , an embodiment of the present invention provides a capacitive screen smart panel 100, including: a whole machine 10, a capacitive screen 20, a liquid crystal display panel 30, and an isolator 40. The liquid crystal display panel 30 is configured. The whole machine 10 includes a power source 11, a TV main board 12, a capacitive screen control board 13, and a liquid crystal panel driving board 14. The power supply 11 is connected to the TV main board 12, the liquid crystal display board 14 is connected to the liquid crystal display panel 30 and the TV main board 12, and the capacitive screen control board 13 is connected to the capacitive screen 20; The screen control board 13 has a first interface, and the TV main board 12 has a second interface, and the first interface and the second interface are connected by the isolator 40.

In the embodiment of the present invention, the power source 11 supplies power to the TV main board 12, and the liquid crystal panel driving board 14 is connected to the liquid crystal display panel 30, and thus the ground end of the power source 11 and the ground end of the TV main board 12 The ground ends of the liquid crystal display panel 30 are connected to each other. In the prior art, the TV main board 12 and the capacitive screen control board 13 are directly connected through an interface for communication or simultaneous communication and power supply (whether power supply or communication) causes the TV main board 12 and the capacitor. The screen control panel 13 is connected to the capacitor screen 20, and thus the grounding end of the power source 11 (ie, the grounding end of the whole machine 10) and the liquid crystal display panel are actually connected. The ground terminal of 30 and the ground terminal of the capacitive screen 20 are all connected. In the actual working process, the noise signal of the external power grid and the liquid crystal display panel 30 and the whole machine 10 may all work on the grounding end of the whole machine 10 (the actual grounding end of the whole machine 10 is the whole machine 10). The backplane of the machine is disturbed. Since the grounding end of the whole machine 10 is connected to the grounding end of the capacitive screen 20, the interference of the grounding end of the whole machine 10 is transmitted to the grounding end of the capacitive screen 20, and the When the capacitive screen 20 is in operation, the level of the grounding terminal of the capacitive screen 20 is used as a reference. Therefore, when the grounding end of the capacitive screen 20 is disturbed, a change in the reference level may be caused, causing the capacitive screen 20 to be in the touch process. A jump point appears. In particular, when applied to a large-sized capacitive screen, this interference is more pronounced due to an increase in the operating voltage. In severe cases, the capacitive screen may not be written.

In the embodiment of the present invention, in order to prevent interference of the grounding end of the whole machine 10 from being transmitted to the grounding end of the capacitive screen 20, the isolation is added between the TV main board 12 and the capacitive screen control board 13. 40. The isolator 40 is provided with an isolation function, that is, the TV main board 12 and the capacitive screen are controlled under the premise of ensuring normal communication and/or normal power supply and communication between the TV main board 12 and the capacitive screen control board 13. The board 13 becomes an electrically isolated, independent, ungrounded device. Among them, the techniques for implementing isolation include, but are not limited to, transformer isolation, coil isolation, magnetic isolation, optocoupler isolation, etc. The invention is not specifically limited.

In summary, the capacitive screen smart tablet 100 provided by the embodiment of the present invention adds the isolator 40 to the TV main board and the capacitive screen between the TV main board 12 and the capacitive screen control board 13 . The control panel 13 is isolated, so that the interference received by the grounding end of the whole machine 10 is not transmitted to the grounding end of the capacitive screen 20, thereby preventing the capacitive screen 20 from jumping due to interference of the grounding end. The working stability of the capacitive screen 20 is improved.

In order to facilitate an understanding of the present invention, some preferred embodiments of the present invention are further described below.

The USB interface may be a USB 2.0 interface or a USB 3.0 interface, which is not specifically limited in the present invention. Correspondingly, the isolator is a USB isolator.

Taking USB2.0 as an example, it consists of 4 lines in the physical layer: two provide 5V power and ground to the peripherals, and the other two (D+ and D-) form a twisted pair that can transmit differential data. Among them, in the USB transmission, data is transmitted through the high and low levels of the D+ and D- signal lines.

In the preferred embodiment, since the first interface and the second interface communicate and supply power simultaneously, the USB isolator needs to have the power isolation function of the isolated 5V power line and the isolated signal lines (D+ and D). -) Signal isolation.

The technology of the power isolation function includes, but is not limited to, transformer isolation, coil isolation, magnetic isolation, and dedicated isolation power isolation, which are not specifically limited in the present invention.

The techniques of the signal isolation function include, but are not limited to, optocoupler isolation, coil isolation, magnetic isolation, etc., which are not specifically limited in the present invention.

In this embodiment, for example, the USB isolator can be formed by adding a power isolation technology (such as a power isolation chip) to the ADUM4160 chip (USB signal isolator, isolation principle is magnetic isolation). In addition, in other embodiments of the present invention, other methods may be used to implement power isolation and signal isolation. These implementation methods are all within the scope of the present invention and will not be described herein.

As shown in Figure 4, the communication protocol for VB1 data transmission is as follows: VB1 uses two control pins during signal transmission, one is the hot-swap pin HTPDN, and the other is the clock lock pin LOCKN, both of which are pulled by pull-up resistors. When the high level continues, the transmitting end peripheral accesses the receiving device or is in an inactive state. After the receiving end accesses the work, the HTPDN is set low, and CDRtraining (clock data recovery) is started. The transmitting end starts and locks the clock frequency. After the receiving end completes the clock recovery, the LOCKN is set low, the ALNtraining is started, and the available data is started. transmission.

In the preferred embodiment, the isolator 40 can be an isolator based on the VB1 protocol. Since only the communication signal is transmitted between the first interface and the second interface, the isolator 40 only needs to be The signal isolation function is sufficient. The implementation of the specific signal isolation function includes, but is not limited to, optocoupler isolation, magnetic isolation, coil isolation, etc., which are not specifically limited in this embodiment.

The communication mode of UART is shown in Figure 5. Each UART interface includes four pins: VCC: power supply pin, generally 3.3v; GND: ground pin; RXD: receive data pin; TXD: send data pin, its working principle is Each character of the transmitted data is transmitted bit by bit. The meaning of each of them is as follows: Start bit: A signal of logic "0" is issued first, indicating the beginning of the transmitted character. Data bit: Immediately after the start bit. The number of data bits can be 4, 5, 6, 7, 8, etc., forming one character. Usually ASCII code is used. The transmission starts from the lowest bit and is located by the clock. Parity: When this bit is added to the data bit, the number of bits in the "1" should be even (even parity) or odd (odd parity) to verify the correctness of the data transfer. Stop bit: It is the end of a character data. It can be a high level of 1 bit, 1.5 bits, or 2 bits. Since the data is timed on the transmission line and each device has its own clock, it is likely that there is a small out-of-synchronization between the two devices in the communication. The stop bit therefore not only indicates the end of the transmission, but also provides the opportunity for the computer to correct the clock synchronization. The more bits that apply to the stop bit, the greater the tolerance of different clock synchronizations, but the slower the data transfer rate. Idle bit: In the logic "1" state, there is no data transmission on the current line. Baud rate: A measure of the data transfer rate. Represents the number of symbols transmitted per second (symbol). The amount of information (number of bits) represented by a symbol It is related to the order of the symbol. For example, the data transfer rate is 120 characters/second, the transmission uses 256-order symbols, and each symbol represents 8 bits, the baud rate is 120 baud, and the bit rate is 120*8=960 bit/s.

In the actual situation, the UART has two connection modes. The first one is to connect only the TXD and RXD pins. In this case, the isolator 40 only needs to have signal isolation function. The second type is that all four pins are connected. In this case, the isolator 40 needs to have both a signal isolation function and a power isolation function.

The communication process of SPI is shown in Figure 6. The SPI has four signal lines, namely SCLK: serial clock, which is used for synchronous data transmission and output by the host; MOSI: host output slave input data line; MISO: host input from Machine output data line; SS: chip select line, active low, output by the host. On the SPI bus, multiple slaves can appear at a time, but only one master can exist. The master determines the slave to communicate through the chip select line.

In this embodiment, since the first interface and the second interface only perform signal communication, the isolator 40 only needs to have a signal isolation function.

Preferably, the first interface and the second interface are COM ports.

In this embodiment, the COM port may be an RS232 interface, an RS422 interface, an RS485 interface, or other customized interface.

The following describes the three interfaces described above.

For the case of the RS232 interface:

As shown in Figure 7, the RS232 interface has 9 pins. The definition of each pin is shown in Figure 8. It can be seen that for communication, three references must be connected between the first interface and the second interface. The pins are the TXD pin, the RXD pin, and the GND pin. Therefore, the isolator 40 needs to have a power isolation function and a signal isolation function.

For the RS422 interface:

The definition of each pin of the RS422 interface is shown in Figure 9, where the ground pin can be connected or not. The power pins are generally not connected.

For the grounding and/or power line connection, at this time, the isolator 40 needs to have a power isolation function and a signal isolation function.

In the case where the ground line and the power line are not connected, at this time, the isolator 40 is provided with a signal isolation function.

For the case of the RS485 interface.

The RS485 interface has two definitions. The first definition of Figure 10 includes four data transfer pins (TDA-/Y, TDB+/Z, RDA-/A, RDB+/B) and a ground pin GND. Ground pins are usually not connected. At this time, the isolator 40 needs to have a signal isolation function.

In the second definition of Figure 11, the RS485 interface includes two data transfer pins (Data-/B/485-, Data+/A/485+), one ground pin GND, and one power line pin (+9V). ). The ground pin and the power line pin are usually not connected. In this case, the isolator 40 needs to have a signal isolation function.

As shown in Figure 12, the I2C bus is very simple in physical connection, consisting of SDA (serial data line) and SCL (serial clock line) and pull-up resistors. The communication principle is to generate the signals required by the I2C bus protocol for data transmission by controlling the high and low timings of the SCL and SDA lines. In the bus idle state, the two wires are generally pulled high by the pull-up resistor connected above, and remain high. Each module circuit connected on the bus is both a master (the master must have a CPU) The logic module) (or the controller) is the transmitter (or receiver), but there is only one host in the system, and the clock signal is generated by the host.

As can be seen from FIG. 12, at this time, the isolator 40 needs to have a signal isolation function.

Preferably, as shown in FIG. 13 , the capacitive screen smart tablet 100 further includes an AD conversion module 50; the capacitive screen 20 is connected to the capacitive screen control board 13 through a capacitive screen receiving line 21 and a capacitive screen output line 22, The AD conversion module 40 is connected to the capacitive screen receiving line 21.

As shown in FIG. 3, RX1, RX2, and RX3 shown in FIG. 3 are a part of the capacitive screen receiving line 21. The capacitive screen receiving line 21 is configured to send a touch signal (analog signal) detected by the capacitive screen 20 to the capacitive screen control panel 13, and the capacitive screen control panel 13 generates a touch according to the touch signal. Coordinate information, and the touch coordinate information is sent to the TV main board 12, and the touch coordinate information is converted into a touch coordinate value by the TV main board 12, and sent to an external device 60 (such as a PC module or an Android module) The external device 60 responds according to the touch coordinate value, and sends the image information generated after the response to the TV motherboard 12, and the TV motherboard 12 sends the image signal and the screen driving command to the liquid crystal display. The driving board 14 drives the liquid crystal display panel 30 according to the driving command, and finally displays the image information by the display.

In a practical situation, in a smart tablet, especially a large-sized smart tablet, the capacitive screen receiving line 21 may be relatively long due to wiring requirements, which may result in transmission within the capacitive screen receiving line 21. The signal is subject to large interference. In particular, when the transmitted signal is an analog signal, it will generate distortion and superimposed clutter after being interfered, and such distortion and superimposed clutter are difficult to eliminate and recover, and thus may cause touch. The coordinate information is inaccurate, resulting in inaccurate final touch position determination.

To this end, in the embodiment of the present invention, the AD conversion module 50 is added to each of the capacitive screen receiving lines 21, and the AD conversion module 50 can convert an analog signal into a digital signal, although the digital signal is in the transmission process. There may also be a problem of bit error due to interference, but such an error can be eliminated by prior anti-interference coding, thereby ensuring the accuracy of touch coordinate information and improving the accuracy of touch position determination.

Preferably, the AD conversion module 50 is disposed at one end of the capacitive screen receiving line 21 connected to the capacitive screen 20.

In the preferred embodiment, the AD conversion module 50 is disposed at one end of the capacitive screen receiving line 21 connected to the capacitive screen 20, that is, the analog signal is just generated and transmitted on the capacitive screen receiving line 21. When it is converted into a digital signal, the problem that the analog signal is difficult to recover after being interfered by the interference can be minimized, and the accuracy of the touch point judgment is improved.

At present, it should be understood that the AD conversion module 50 may be disposed at one end of the capacitive screen receiving line 21 close to the capacitive screen 20, which is not specifically limited by the present invention.

Preferably, the whole machine 10 further includes a whole machine backplane, and the capacitive screen control board 13 is mounted on the The capacitive screen receiving line 21 and the capacitive screen output line 22 are taken out from the capacitive screen control board 13 and connected to the capacitive screen along the inner wall of the whole machine backplane. Wherein the capacitive screen receiving line 21 and the capacitive screen output line 22 have a conductor layer, a first insulating layer encasing the conductor layer, and a shielding layer encasing the first insulating layer, the shielding layer and the shielding layer The inner wall of the back plate of the whole machine is insulated.

In this embodiment, the back plate of the whole machine is made of a metal material, and on the one hand, functions as a fixed support, and the TV circuit board 12, the capacitive screen control board 13 and various circuit board covers are fixed at the whole. On the back of the machine. On the other hand, as described above, the whole machine backplane is also the largest ground in the whole machine 10, in the sense of the circuit. In the prior art, the capacitive screen receiving line 21 and the capacitive touch screen emitting line 24 are closely aligned with the inner wall of the whole machine backplane. During the working process, the whole backplane may be subjected to the liquid crystal display. The panel 30 interferes, and the entire backplane is disturbed to generate spatial radiation that interferes with signals transmitted within the capacitive screen receiving line 21 and the capacitive screen output line 22.

For this reason, please refer to FIG. 14 , taking the capacitive screen receiving line 21 as an example. In the embodiment, the capacitive screen receiving line 21 has a conductor layer 211 and a first insulating layer enclosing the conductor layer 211 . 212 and a shielding layer 213 surrounding the first insulating layer 212, and the shielding layer 213 is insulated from the whole backing plate.

In this embodiment, the conductor layer 211 is used for signal transmission, the first insulating layer 212 functions to insulate the conductor layer 211, and the shielding layer 213 may be a metal shielding layer. The interference of the spatial radiation of the entire backplane to the signals transmitted within the conductor layer 211 can be shielded. Since the shielding layer 233 is a metal shielding layer, it is also necessary to perform insulation treatment on the shielding layer 213.

Specifically, a second insulating layer 214 surrounding the shielding layer 213 may be disposed outside the shielding layer 213, or an insulating spacer may be interposed between the shielding layer 213 and the whole backing plate, so that the The shielding layer 213 is physically separated from the whole machine backplane, and may also be insulated by a portion of the whole machine backplane that is in contact with the shielding layer 213, wherein, preferably, the shielding layer is A second insulating layer 214 covering the shielding layer 213 is disposed outside the layer 213, and a better insulating effect has been achieved.

Similarly, the capacitive screen output line 22 is similarly insulated, and the present invention will not be described herein.

Preferably, the smart tablet 100 further includes a power isolator 70, and the power source 11 is connected to the capacitive screen control board 13 through the power isolator 70.

In some cases, the capacitive screen control panel 13 cannot be powered directly by the TV motherboard 12 through the interface. For example, the pins of the interface do not contain power pins or the power pins are not connected or the pins of the interface contain power pins, but the power provided is not sufficient to drive the capacitive screen control board 13 to operate. In particular, for a large-sized capacitive screen smart panel, even if the interface has a power supply pin, the power supplied through the power supply pin is often insufficient to drive the capacitive screen control panel 13.

To this end, as shown in FIG. 15, in the preferred embodiment, the capacitive screen control panel 13 is directly powered by the power source 11, at this time, between the power source 11 and the capacitive screen control panel 13. A power isolator 70 is connected to implement power isolation between the power source 11 and the capacitive screen control board 13, so that the ground of the power supply 11, the TV main board 12 and the ground of the capacitive screen 20 are no longer connected, thereby avoiding The grounding interference received by the grounding end of the whole machine 10 affects the grounding end of the capacitive screen 20.

It should be noted that, similarly, the liquid crystal panel driving board 14 also has two power supply modes. For a small-sized smart tablet, the liquid crystal panel driving board 14 can be powered by the TV main board 12, and is for a large size. The smart panel, the LCD panel driver board 14 is powered by the power source 11. The above is only the preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, and those skilled in the art can understand all or part of the process of implementing the above embodiments, and according to the claims of the present invention. Equivalent changes made are still within the scope of the invention.

One of ordinary skill in the art can understand that all or part of the process of implementing the foregoing embodiments can be completed by a computer program to instruct related hardware, and the program can be stored in a computer readable storage medium. When executed, the flow of an embodiment of the methods as described above may be included. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

Claims

A capacitive screen smart panel, comprising: a whole machine, a capacitive screen, a liquid crystal display panel and an isolator, wherein the liquid crystal display panel is disposed between the whole machine and the capacitive screen; wherein The device includes a power source, a TV motherboard, a capacitive screen control panel, and a liquid crystal panel driving board; the power source is connected to the TV motherboard; the LCD panel driving board is connected to the liquid crystal display panel and the TV motherboard, and the capacitive screen The control panel is connected to the capacitive screen; the capacitive screen control panel has a first interface, the TV motherboard has a second interface, and the first interface and the second interface are connected by the isolator.
The capacitive screen smart tablet according to claim 1, wherein the isolator has a signal isolation function.
The capacitive screen smart tablet according to claim 1, wherein the isolator has both a power isolation function and a signal isolation function.
The capacitive screen smart tablet according to any one of claims 1 to 3, wherein the first interface and the second interface are USB interfaces, and the isolator is a USB isolator.
The capacitive screen smart tablet according to claim 4, wherein the first interface and the second interface are USB 2.0 interfaces.
The capacitive screen smart tablet according to claim 4, wherein the first interface and the second interface are USB 3.0 interfaces.
The capacitive screen smart tablet according to any one of claims 1 to 3, characterized in that The first interface and the second interface are interfaces based on the VB1 protocol.
The capacitive screen smart tablet according to any one of claims 1 to 3, wherein the first interface and the second interface are interfaces based on a UART protocol.
The capacitive screen smart tablet according to any one of claims 1 to 3, wherein the first interface and the second interface are interfaces based on an SPI protocol.
The capacitive screen smart tablet according to any one of claims 1 to 3, wherein the first interface and the second interface are COM ports.
The capacitive screen smart tablet according to any one of claims 1 to 3, wherein the first interface and the second interface are interfaces based on an I2C protocol.
The capacitive screen smart tablet according to claim 1, wherein the capacitive screen smart tablet further comprises an AD conversion module; the capacitive screen is connected to the capacitive screen control board through a capacitive screen receiving line and a capacitive screen output line. The AD conversion module is connected to the capacitive screen receiving line.
The capacitive screen smart tablet according to claim 12, wherein the AD conversion module is disposed at one end of the capacitive screen receiving line connected to the capacitive screen.
The capacitive screen smart tablet according to claim 12, wherein the whole machine further comprises a whole machine backplane, wherein the capacitive screen control board is hung on the whole machine backboard; the capacitive screen receiving line And the capacitive screen output line is taken out from the capacitive screen control board, and is connected to the capacitive screen body along the inner wall of the whole machine backplane; wherein the capacitor receiving line and the capacitor output line With a conductor layer, And a first insulating layer encapsulating the conductor layer and a shielding layer enclosing the first insulating layer, and the shielding layer is insulated from the inner wall of the whole backing plate.
The capacitive screen smart tablet according to claim 14, wherein

a second insulating layer enclosing the shielding layer is disposed outside the shielding layer; or

An insulating spacer is interposed between the shielding layer and an inner wall of the whole machine backboard; or

An insulating tape is attached to a portion of the inner wall of the whole machine back plate that is in contact with the shielding layer.
The capacitive screen smart tablet according to any one of claims 1 to 12, further comprising a power isolator, wherein the power source is connected to the capacitive screen control board through the power isolator.