Mobile terminal protection shell

Abstract

The utility model provides a mobile terminal protection shell which comprises an NFC antenna, a display mainboard, a display screen and a shell body, the NFC antenna, the display mainboard and the display screen are arranged on the shell body, a camera through hole is formed in the top area, close to the shell body, of the shell body, and the NFC antenna is located on the side face of the camera through hole and arranged opposite to the NFC antenna of the mobile terminal. The display main board is located on the side face of the camera through hole and the bottom face of the camera through hole, the display main board is located on the side, away from the NFC antenna and the camera through hole, of the display main board, the NFC antenna is electrically connected with the display main board, the display main board is electrically connected with the display screen, the NFC antenna is used for receiving signals of the NFC reader-writer, the display main board comprises an NFC chip containing access control certificate information, and the NFC chip is electrically connected with the display screen. The NFC chip is used for receiving and processing a signal transmitted by the NFC antenna, the display screen is used for displaying related information, and the NFC antenna is formed by winding a wire, so that the mobile terminal protection shell has an access control function, and the safety of an access control system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of mobile terminal accessories, and in particular to a mobile terminal protective case. Background Art

[0002] With the rapid development of smart mobile terminal technology, mobile terminal protective cases are no longer just for device protection; they're also becoming a way to showcase your personality and enhance functionality. E-paper display technology is gaining popularity in the market due to its low power consumption and eye-friendly features, while NFC technology supports mobile payments, identity authentication, and other functions, further enhancing the practicality of mobile terminal protective cases. However, current mobile terminal protective cases lack access control functionality, requiring a traditional access card to unlock the device, which can be insecure. Utility Model Content

[0003] In view of this, the present application provides a mobile terminal protective case to improve the security of the access control system.

[0004] The present application provides a mobile terminal protective case, comprising an NFC antenna, a display motherboard, a display screen and a shell, wherein the NFC antenna, the display motherboard and the display screen are arranged on the shell, and a camera through-hole is provided in the shell near the top area of ​​the shell, the NFC antenna is located on the side of the camera through-hole and is arranged opposite to the NFC antenna of the mobile terminal, the display motherboard is located on the side of the camera through-hole and the bottom of the camera through-hole, the display motherboard is located on the side of the display motherboard away from the NFC antenna and the camera through-hole, the NFC antenna is electrically connected to the display motherboard, the display motherboard is electrically connected to the display screen, the NFC antenna is used to receive signals from an NFC reader / writer, the display motherboard includes an NFC chip containing access control credential information, the NFC chip is used to receive and process signals transmitted by the NFC antenna, the display screen is used to display relevant information, and the NFC antenna is formed by winding a wire.

[0005] In some embodiments, the display mainboard further includes an NFC pad and a circuit board, the NFC pad being connected to the NFC antenna and the NFC chip, respectively, the NFC chip being located on a side of the NFC pad facing away from the NFC antenna, and the circuit board being located on a side of the NFC chip away from the NFC chip, and the circuit board being used to process and transmit data.

[0006] In some embodiments, the display main board further includes a circuit pad for connecting to the display screen, and the circuit pad is located on a side of the circuit board away from the NFC chip.

[0007] In some embodiments, the NFC chip includes a rectifier circuit for converting the alternating current received by the NFC antenna into a direct current.

[0008] In some embodiments, the rectifier circuit includes a shaping circuit module, a voltage stabilizing circuit module, a first control circuit module, a second control circuit module, and a filtering and energy storage circuit module. The shaping circuit module is connected to the voltage stabilizing circuit module and the first control circuit module, the first control circuit module is connected to the filtering and energy storage circuit module, the first control circuit module is connected to the second control circuit module, the shaping circuit module is used to rectify the alternating signal, the voltage stabilizing circuit module is used to limit the output voltage, the first control circuit module is used to control the output voltage stability, the second control circuit module is used to amplify the input current and control the switch of the first control circuit module, and the filtering and energy storage circuit module is used for filtering.

[0009] In some embodiments, the shaping circuit module includes a first Schottky diode, a second Schottky diode, a third Schottky diode, and a fourth Schottky diode. The first input end of the NFC chip is respectively connected to the anode of the first Schottky diode and the cathode of the second Schottky diode, the second input end of the NFC chip is respectively connected to the cathode of the third Schottky diode and the anode of the fourth Schottky diode, and the anode of the second Schottky diode and the anode of the third Schottky diode are both grounded.

[0010] In some embodiments, the voltage stabilizing circuit module includes a voltage stabilizing diode, a cathode of the voltage stabilizing diode is connected to the output end of the shaping circuit module, and an anode of the voltage stabilizing diode is grounded.

[0011] In some embodiments, the first control circuit module includes a P-type channel field effect transistor, a first resistor and a second resistor, the source of the P-type channel field effect transistor is connected to the output end of the shaping circuit module, the first ends of the first resistor and the second resistor are connected to the source of the P-type channel field effect transistor, the second end of the first resistor is connected to the drain of the P-type channel field effect transistor, and the second end of the second resistor is connected to the gate of the P-type channel field effect transistor.

[0012] In some embodiments, the second control circuit module includes an N-type channel field effect transistor and a third resistor, the drain of the N-type channel field effect transistor is connected to the gate of the P-type channel field effect transistor, the source of the N-type channel field effect transistor is grounded, the third resistor is connected to the gate of the N-type channel field effect transistor, and the gate of the N-type channel field effect transistor is used to input a control signal.

[0013] The present application provides a mobile terminal protective case, including an NFC antenna, a display motherboard, a display screen and a shell. The NFC antenna, display motherboard and display screen are arranged on the shell. A camera through-hole is provided in the shell near the top area of ​​the shell. The NFC antenna is located on the side of the camera through-hole and is arranged opposite to the NFC antenna of the mobile terminal. The display motherboard is located on the side of the camera through-hole and on the bottom of the camera through-hole. The display motherboard is located on the side of the display motherboard away from the NFC antenna and the camera through-hole. The NFC antenna is electrically connected to the display motherboard, and the display motherboard is electrically connected to the display screen. The NFC antenna is used to receive signals from an NFC reader. The display motherboard includes an NFC chip containing access control credential information. The NFC chip is used to receive and process signals from the NFC antenna. The display screen is used to display relevant information. The NFC antenna is formed by winding a wire, so that the mobile terminal protective case has an access control function, thereby improving the security of the access control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 This is a schematic diagram of the planar structure of the mobile terminal protective case provided by this application;

[0016] Figure 2 This is a schematic diagram of the planar structure of the NFC antenna and display motherboard provided by this application;

[0017] Figure 3 yes Figure 2 Schematic diagram of the planar structure of the NFC antenna;

[0018] Figure 4 This is a schematic diagram of the planar structure of another NFC antenna provided by this application;

[0019] Figure 5 This is a schematic diagram of the planar structure of another NFC antenna provided by this application;

[0020] Figure 6 This is a schematic diagram of the NFC antenna matching circuit provided by this application;

[0021] Figure 7 It is a schematic diagram of a rectifier circuit provided by this application;

[0022] Figure 8 This is a flow chart of the method for opening access control of a mobile terminal protective case provided by this application.

[0023] Reference numerals:

[0024] 10. Mobile terminal protective case; 100. NFC antenna; 110. First via hole; 120. Second via hole; 200. Display motherboard; 210. NFC chip; 220. NFC pad; 230. Circuit board; 240. Circuit pad; 300. Display screen; 400. Housing; 500. Decorative structure hole. DETAILED DESCRIPTION

[0025] The following, in conjunction with the accompanying drawings, clearly and completely describes the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0026] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of this application, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the relevant listed items. The terms "connected", "electrically connected", and "electrically connected" as used herein include any direct and indirect electrical or structural connection means. Therefore, if the text describes a first device as being coupled / connected / electrically connected to a second device, it means that the first device can be directly electrically / structurally connected to the second device, or indirectly electrically / structurally connected to the second device through other devices or connection means.

[0028] The present application provides a mobile terminal protective case, including an NFC antenna, a display motherboard, a display screen and a shell. The NFC antenna, display motherboard and display screen are arranged on the shell. A camera through-hole is provided in the shell near the top area of ​​the shell. The NFC antenna is located on the side of the camera through-hole and is arranged opposite to the NFC antenna of the mobile terminal. The display motherboard is located on the side of the camera through-hole and on the bottom of the camera through-hole. The display motherboard is located on the side of the display motherboard away from the NFC antenna and the camera through-hole. The NFC antenna is electrically connected to the display motherboard, and the display motherboard is electrically connected to the display screen. The NFC antenna is used to receive signals from an NFC reader / writer. The display motherboard includes an NFC chip containing access control credential information. The NFC chip is used to receive and process signals from the NFC antenna. The display screen is used to display relevant information. The NFC antenna is formed by winding a wire.

[0029] In this application, by integrating an NFC chip containing access control credential information into a mobile terminal case, the mobile terminal protective case is endowed with an access control function, so that the mobile terminal protective case can be used to touch or approach the access control device to open the access control, thereby reducing the risk of illegal access and improving the security of the access control system. There is no need to carry a traditional access control card, which improves convenience.

[0030] See also Figure 1-Figure 3 , Figure 1 This is a schematic diagram of the planar structure of the mobile terminal protective case provided by this application; Figure 2 This is a schematic diagram of the planar structure of the NFC antenna and display motherboard provided by this application; Figure 3 yes Figure 2The application provides a mobile terminal protective shell 10, which comprises an NFC antenna 100, a display mainboard 200, a display screen 300 and a shell 400. The NFC antenna 100, the display mainboard 200 and the display screen 300 are arranged on the shell 400. The shell 400 is provided with a camera through hole near a top area of the shell 400. The NFC antenna 100 is arranged on a side of the camera through hole and opposite to a mobile terminal NFC antenna. The display mainboard 200 is arranged on a side of the camera through hole and a bottom surface of the camera through hole. The display mainboard 200 is arranged on a side of the display mainboard 200, which is away from the NFC antenna 100 and the camera through hole. The NFC antenna 100 is electrically connected with the display mainboard 200. The display mainboard 200 is electrically connected with the display screen 300. The NFC antenna 100 is used for receiving a signal of an NFC reader-writer. The display mainboard 200 comprises an NFC chip 210 containing access control certificate information. The NFC chip 210 is used for receiving and processing the signal transmitted by the NFC antenna 100. The display screen 300 is used for displaying relevant information.Specifically, the NFC antenna 100 is arranged opposite to the NFC antenna of the mobile terminal, that is, the NFC antenna 100 is located in an area close to the NFC antenna of the mobile terminal, the NFC antenna 100 and the display motherboard 200 are both located on the inner side of the shell 400, and the display screen 300 is located on the outer side of the shell 400. The NFC antenna 100 and the display motherboard 200 can be connected to the shell 400 by adhesive, or the NFC antenna 100 can be directly pad printed on the shell 400, and the display screen 300 can be connected to the shell 400 by snapping, such as providing a fixing hole that passes through the shell 400 on the shell 400, and the display screen 300 is snapped into the fixing hole; the NFC antenna 100 is composed of an NFC coil formed by winding a wire, and the end of the NFC coil closest to the center of the NFC coil extends to the outside of the NFC coil through the first via 110 and the second via 120 to be connected to the first input terminal RF1 of the NFC chip 210, the first via 110 is located on the inner side of the NFC coil, and the second via 120 is located on the outside of the NFC coil, and the NFC coil is away from the center of the NFC coil. The head end of the core is adjacent to the end of the NFC coil and is arranged at an interval. The head end of the NFC coil is connected to the second input terminal RF2 of the NFC chip 210; the NFC antenna 100 is connected to the NFC chip 210 through the first input terminal RF1 of the NFC chip 210 and the second input terminal RF2 of the NFC chip 210, that is, the NFC antenna 100 is electrically connected to the display motherboard 200; the display motherboard 200 is electrically connected to the display screen 300; the NFC antenna 100 is used to receive signals from the NFC reader / writer. Furthermore, the NFC antenna 100 transmits energy to the entire circuit system by inducing an external electromagnetic field, and at the same time receives data signals for subsequent decoding and processing; the display motherboard 200 includes an NFC chip 210 containing access control credential information. The access control credential information in the NFC chip 210 is written by the target application of the mobile terminal. The NFC chip 210 is used to receive and process signals from the NFC antenna 100 and convert these signals into digital information; the display screen 300 is used to display relevant information; the NFC antenna 100 is composed of enameled wire.

[0031] In the present application, by integrating the NFC chip 210 containing access control credential information into the mobile terminal case, the mobile terminal protective case 10 is endowed with an access control function, so that the mobile terminal protective case 10 can be used to touch or approach the access control device to open the access control, thereby reducing the risk of illegal access, thereby improving the security of the access control system, and eliminating the need to carry a traditional access control card, thereby improving convenience; in addition, the NFC antenna 100 is located in an area close to the mobile terminal NFC antenna to shorten the distance between the NFC antenna 100 and the mobile terminal NFC antenna, reducing the risk of signal attenuation, thereby improving the reliability of NFC communication.

[0032] In the present application, the NFC antenna 100 is disposed in the top area of ​​the housing 400 to further shorten the distance between the NFC antenna 100 and the NFC antenna of the mobile terminal, thereby ensuring a more stable signal and a stronger electromagnetic field, thereby further improving communication efficiency.

[0033] In one embodiment, the diameter of the enameled wire may be 150 to 230 microns. Specifically, 150 microns, 154 microns, 155 microns, 160 microns, 161.07 microns, 165.5 microns, 168.7 microns, 170 microns, 180 microns, 195 microns, 200 microns, 200.4 microns, 205 microns, 210 microns, 214.7 microns, 215.9 microns, 220 microns, 221 microns, 225 microns, or 230 microns. Setting the diameter of the enameled wire within this range ensures that the NFC antenna 100 has good energy transmission efficiency while preventing the enameled wire from being too large, which would otherwise cause the NFC antenna 100 to be too large and the mobile terminal protective case 10 to be too thick.

[0034] In one embodiment, the NFC antenna 100 near the first input terminal RF1 of the NFC chip 210 has a recessed portion that is recessed toward the inside of the NFC antenna 100, and the recessed portion near the first input terminal RF1 of the NFC chip 210 has a greater depth than the recessed portion away from the first input terminal RF1 of the NFC chip 210. The NFC antenna 100 is also provided with a recessed portion on the side facing away from the first input terminal RF1 of the NFC chip 210 and on the same side as the recessed portion near the first input terminal RF1 of the NFC chip 210, and the recessed portion has a greater depth than the recessed portion near the first input terminal RF1 of the NFC chip 210 and the recessed portion away from the first input terminal RF1 of the NFC chip 210.

[0035] In another embodiment, the NFC antenna 100 may be replaced by an additive antenna having NFC functionality, and the additive antenna is formed by 3D printing.

[0036] In one embodiment, the length and width of the NFC antenna 100 are 30 mm and 15 mm respectively, and the inductance of the NFC antenna 100 is 0.4 uH-1.5 uH. The area of ​​the NFC antenna 100 is set within this range to ensure that the NFC antenna 100 has sufficient area to receive and transmit signals, and at the same time, electromagnetic interference will not occur to affect the cellular network signal, and it is easy to be installed on the housing 400; the inductance of the NFC antenna 100 is set to 0.4 uH-1.5 uH to ensure the stability and efficiency of NFC communication.

[0037] In an embodiment, the NFC antenna 100 and the NFC chip 210 transmit energy and signals through the NFC antenna 100 matching circuit, which is used to adjust the impedance matching of the antenna to ensure that the antenna can efficiently transmit energy and signals between the NFC circuit. Specifically, the NFC antenna 100 matching circuit includes a first capacitor C1, a second capacitor C2, the NFC antenna 100, a second input end RF2 of the NFC chip 210, and a first input end RF1 of the NFC chip 210. The first capacitor C1 is connected in series with the second capacitor C2, the NFC antenna 100 is connected with the first capacitor C1 and the second capacitor C2, and the series-connected first capacitor C1 and second capacitor C2 are connected to the second input end RF2 of the NFC chip 210 and the first input end RF1 of the NFC chip 210. The capacitance of the first capacitor C1 is 100-150 pF, and the capacitance of the second capacitor C2 is 28-50 pF. Specifically, the capacitance of the first capacitor C1 can be 100 pF, 107 pF, 114 pF, 123 pF, 120 pF, 134 pF, 146 pF, or 150 pF, and the capacitance of the second capacitor C2 can be 28 pF, 30 pF, 37 pF, 39 pF, 43 pF, 47 pF, or 50 pF. Preferably, the capacitance of the first capacitor C1 is 120 pF, and the capacitance of the second capacitor C2 is 39 pF. The capacitance of the first capacitor C1 and the capacitance of the second capacitor C2 are set in this range to further improve the signal transmission and reception efficiency in the high-frequency circuit. When the NFC antenna 100 receives the electromagnetic signal generated by the external NFC reader / writer, the NFC antenna 100 will induce the electromagnetic signal and generate an alternating current signal. The first capacitor C1 and the second capacitor C2 together with the inductance of the NFC antenna 100 form an LC resonance circuit, and the resonance frequency of the LC circuit needs to be consistent with the frequency (12-14 MHz) of the NFC signal to achieve the best energy coupling. When the impedance matching is good, the electromagnetic energy received by the NFC antenna 100 can be efficiently transmitted to the RF input end of the NFC chip 210, ensuring the transmission quality of the signal.

[0038] In this application, the NFC antenna 100 and the NFC chip 210 transmit energy and signals through the NFC antenna 100 matching circuit, so that the NFC antenna 100 can efficiently transmit energy and signals between the NFC circuit, ensuring the communication quality. By adjusting the values of the first capacitor C1 and the second capacitor C2, the impedance of the antenna can be adjusted to match the impedance of the NFC chip 210, thereby improving the signal transmission efficiency. At the same time, the resonance frequency of the NFC antenna 100 can be adjusted to achieve impedance matching with the 12-14 MHz signal. Impedance matching can reduce signal loss and improve reception and transmission efficiency.

[0039] In an embodiment, the display mainboard 200 further comprises an NFC pad 220 and a circuit board 230, the NFC pad 220 is connected with the NFC antenna 100 and the NFC chip 210 respectively, the NFC chip 210 is located on the side of the NFC pad 220 away from the NFC antenna 100, and the circuit board 230 is located on the side of the NFC chip 210 away from the NFC chip 210, and the circuit board 230 is used for processing and transmitting data. Specifically, the circuit board 230 is a multi-layer PCB board, the multi-layer PCB board is used for connecting various electronic components to ensure the stability of the circuit and the reliability of the signal transmission, and the NFC pad 220 is used for transmitting the signal received by the NFC antenna 100 to the NFC chip 210. The circuit board 230 is set as a multi-layer PCB board to improve the anti-interference performance and ensure the integrity of the data and the effective transmission of the power supply.

[0040] In an embodiment, a PCB antenna is further arranged on the circuit board 230, so that the PCB antenna can be directly connected with other radio frequency elements on the circuit board 230, reducing the signal loss caused by the connecting line and improving the efficiency of the antenna and the signal transmission quality.

[0041] In an embodiment, the display mainboard 200 further comprises a line pad 240 used for connecting the display screen 300, the line pad 240 is located on the side of the circuit board 230 away from the NFC chip 210, and the line pad 240 is used for transmitting energy to the display screen 300 to enable the display screen 300 to display relevant information.

[0042] Please refer to Figure 4 , Figure 4 is another schematic view of a planar structure of the NFC antenna 100 provided in the present application. It should be noted that Figure 4 is different from Figure 3 in that: Figure 4 is different from Figure 3 in that the NFC antenna 100 is a mirror-symmetrical structure. Other than that, it is the same as Figure 3 , and details are not repeated here.

[0043] Please refer to Figure 5 , Figure 5 is another schematic view of a planar structure of the NFC antenna 100 provided in the present application. It should be noted that Figure 5 is different from Figure 3 in that the NFC antenna 100 is arranged around the decorative structure hole 500. Other than that, it is the same as Figure 3 , and details are not repeated here.

[0044] In an embodiment, the NFC chip 210 contains a rectifier circuit used for converting the alternating current received by the NFC antenna 100 into direct current.

[0045] In one embodiment, the rectifier circuit includes a shaping circuit module, a voltage stabilizing circuit module, a first control circuit module, a second control circuit module, and a filtering and energy storage circuit module. The shaping circuit module is connected to the voltage stabilizing circuit module and the first control circuit module, the first control circuit module is connected to the filtering and energy storage circuit module, and the first control circuit module is connected to the second control circuit module. The shaping circuit module is used to rectify the alternating signal, the voltage stabilizing circuit module is used to limit the output voltage, the first control circuit module is used to control the output voltage stability, the second control circuit module is used to amplify the input current and control the switching of the first control circuit module, and the filtering and energy storage circuit module is used for filtering. Specifically, the input end of the shaping circuit module is connected to the second input end RF2 of the NFC chip 210 and the first input end RF1 of the NFC chip 210, respectively.

[0046] The output end of the shaping circuit module is connected to the voltage stabilizing circuit module and the first control circuit module respectively. The output end of the first control circuit module is connected to the input end of the filtering and energy storage circuit module. The first control circuit module is connected to the second control circuit module. The output end of the filtering and energy storage circuit module and the output end of the first control circuit module are connected to the DC output end (DC-DC IN) connection; the shaping circuit module is used to invert the negative half-cycle of the alternating current signal (AC) received from the NFC antenna 100 to convert it into a unidirectional pulsating direct current (DC) signal. The function of the voltage stabilizing circuit module is to limit the output voltage. For example, when the rectified output voltage exceeds the breakdown voltage of the voltage stabilizing circuit module, the voltage stabilizing circuit module will enter the on state and release the excess voltage to the ground through the voltage stabilizing circuit module, thereby protecting the subsequent circuit. By discharging the excess voltage to the ground, the voltage stabilizing circuit module can protect subsequent components and prevent them from being damaged by excessive voltage. The first control circuit module is used to stabilize the voltage and control the on and off of the output current. The second control circuit module is used to amplify the input current and control the switching of the first control circuit module. The filtering and energy storage circuit module is used to smooth the rectified pulsating DC into a stable DC signal. The DC output terminal is used to output the rectified DC signal for use by other circuits.

[0047] In one embodiment, the shaping circuit module includes a first Schottky diode D1, a second Schottky diode D2, a third Schottky diode D3, and a fourth Schottky diode D4. The first input terminal RF1 of the NFC chip 210 is connected to the anode of the first Schottky diode D1 and the cathode of the second Schottky diode D2, respectively. The second input terminal RF2 of the NFC chip 210 is connected to the cathode of the third Schottky diode D3 and the anode of the fourth Schottky diode D4, respectively. The anodes of the second Schottky diode D2 and the third Schottky diode D3 are both grounded. The shaping circuit module, composed of the first Schottky diode D1, the second Schottky diode D2, the third Schottky diode D3, and the fourth Schottky diode D4, allows AC signals to pass in only one direction, forming a pulsating DC current.

[0048] In one embodiment, the voltage-stabilizing circuit module includes a voltage-stabilizing diode D5. The cathode of the voltage-stabilizing diode D5 is connected to the output of the shaping circuit module, and the anode of the voltage-stabilizing diode D5 is grounded. Within the normal output range of the rectifier circuit, the voltage-stabilizing diode D5 does not conduct, and current does not flow through the voltage-stabilizing diode D5. At this time, the voltage at the rectifier output is smoothed by the capacitor, becoming a stable DC voltage for use by subsequent circuits. When the voltage at the rectifier output exceeds the breakdown voltage of the voltage-stabilizing diode D5 (typically set to the upper operating voltage limit of the circuit), the voltage-stabilizing diode D5 "breaks down," conducting and beginning to divert current to ground. This breakdown is controllable and does not damage the voltage-stabilizing diode D5. When the rectifier voltage drops below the breakdown voltage, the voltage-stabilizing diode D5 returns to a cutoff state, preventing current from flowing to ground and ensuring normal circuit operation.

[0049] In the present application, the Zener diode D5 is used to enter the on state when the rectified output voltage exceeds the breakdown voltage of the Zener diode D5, and release the excess voltage to the ground through the Zener diode D5, thereby protecting the subsequent circuit, that is, limiting the output voltage; the Zener diode D5 protects subsequent components by discharging the excess voltage to the ground, avoiding damage to them due to excessive voltage, that is, playing the role of overvoltage protection.

[0050] In an embodiment, the first control circuit module comprises a P-channel MOSFET Q1, a first resistor R1 and a second resistor R2, the source of the P-channel MOSFET Q1 is connected to the output of the shaping circuit module, the first end of the first resistor R1 and the second resistor R2 is connected to the source of the P-channel MOSFET Q1, the second end of the first resistor R1 is connected to the drain of the P-channel MOSFET Q1, the second end of the second resistor R2 is connected to the gate of the P-channel MOSFET Q1, the P-channel MOSFET Q1 controls the smoothness of the output voltage and prevents excessive current or voltage from being output to the subsequent circuit. When the gate voltage of the P-channel MOSFET Q1 is low (such as the gate of the P-channel MOSFET Q1 is grounded or negative voltage), the P-channel MOSFET Q1 is turned on, so that the current can flow from the source of the P-channel MOSFET Q1 to the drain of the P-channel MOSFET Q1, thereby providing current for the load. When the gate voltage of the P-channel MOSFET Q1 is high (such as close to the source voltage), the N-channel MOSFET Q2 is turned off and the current is blocked. The on and off states of the P-channel MOSFET Q1 are controlled by the gate voltage. The gate voltage is limited by the second resistor R2 to avoid excessive voltage causing the P-channel MOSFET Q1 to lose control. The P-channel MOSFET Q1 can provide a relatively stable output voltage to the subsequent circuit when turned on, i.e. the P-channel MOSFET Q1 has the functions of voltage stabilization, current control and switching control, i.e. the P-channel MOSFET Q1 is turned on or off under the control of the N-channel MOSFET Q2, thereby controlling whether the current passes to the subsequent circuit, achieving voltage stabilization and control of the output.

[0051] In an embodiment, the second control circuit module comprises an N-channel MOSFET Q2 and a third resistor R3, the drain of the N-channel MOSFET Q2 is connected to the gate of the P-channel MOSFET Q1, the source of the N-channel MOSFET Q2 is grounded, the third resistor R3 is connected to the gate of the N-channel MOSFET Q2, the gate of the N-channel MOSFET Q2 is used for inputting a control signal (such as SW IO), and the N-channel MOSFET Q2 controls the smoothness of the output voltage and prevents excessive current or voltage from being output to the subsequent circuit.

[0052] In the present application, the drain of the N-type channel field effect transistor Q2 is set to be connected to the gate of the P-type channel field effect transistor Q1, and the source of the N-type channel field effect transistor Q2 is set to be grounded. When the input terminal (connected to SW_IO) gives the N-type channel field effect transistor Q2 a voltage signal, the gate voltage of the N-type channel field effect transistor Q2 changes, and its drain current increases or decreases accordingly, thereby achieving a current amplification effect. That is, this connection method helps to amplify the input signal; when SW_IO is at a high level, the N-type channel field effect transistor Q2 is turned on, thereby making the P The gate voltage of the N-type channel field effect transistor Q1 decreases, turning on the P-type channel field effect transistor Q1; when SW_IO is at a low level, the N-type channel field effect transistor Q2 is turned off, the gate voltage of the P-type channel field effect transistor Q1 returns to a higher level, and the P-type channel field effect transistor Q1 is turned off; when the SW_IO input level is too high or too low, the N-type channel field effect transistor Q2 will automatically adjust the conduction state of Q1 to avoid damage to subsequent circuits, that is, the N-type channel field effect transistor Q2 amplifies the input current through the SW_IO control signal and controls the switch of Q1.

[0053] In one embodiment, the filtering and energy storage circuit module includes a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a sixth capacitor C6. The first ends of the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are all connected to the output end of the first control circuit module, and the second ends of the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are all grounded. The third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 store charge and release the charge during pulse intervals to smooth voltage fluctuations and make the output a stable DC.

[0054] When an NFC reader approaches, the high-frequency AC signal generated by the NFC reader is received by the NFC antenna 100 and input to the shaping circuit through the first input terminal RF1 and the second input terminal RF2 of the NFC chip 210. The negative half-cycle of the AC signal is then inverted by the first Schottky diode D1, the second Schottky diode D2, the third Schottky diode D3, and the fourth Schottky diode D4, converting the output into a pulsating DC current (i.e., rectifying the AC signal). When the output voltage of the shaping circuit is too high, the circuit turns on, discharging the excess voltage to ground, thereby stabilizing and protecting the voltage and preventing voltage fluctuations from affecting subsequent circuits. The smoothness of the output voltage is then controlled by the P-type channel field-effect transistor Q1 and the N-type channel field-effect transistor Q2, preventing excessive current or voltage from being output to subsequent circuits. Filter capacitors, such as the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6, store charge and release it between pulses, smoothing the pulsating DC signal into a stable DC voltage for use by subsequent circuits.

[0055] See also Figure 7 , Figure 7 This is a flow chart of the method for opening access control using a mobile terminal protective case provided by this application. This application also provides a method for controlling access control opening using a mobile terminal protective case 10, which is operated using the mobile terminal protective case 10 provided by this application, including:

[0056] S11. Control the mobile terminal protective case to scan the NFC reader / writer, and the NFC reader / writer obtains the NFC chip of the mobile terminal protective case.

[0057] Specifically, the mobile terminal protective case 10 includes an NFC chip 210 and a display screen 300. The NFC chip 210 stores access control credentials (such as an ID or encrypted access control key), while the display screen 300 can display relevant information. The user's mobile terminal target application can update or import access control credentials and write them to the NFC chip 210 of the mobile phone case via NFC. This process is usually achieved by importing the target application into the system.

[0058] S12. The NFC reader / writer performs near field communication with the mobile terminal protective case.

[0059] S13. The radio frequency signal sent by the NFC reader is transmitted to the NFC chip through the NFC antenna.

[0060] S14. The NFC chip decodes the radio frequency signal and confirms whether the decoded radio frequency signal matches the target information.

[0061] S15. If the decoded radio frequency signal matches the target information, the access control credentials of the NFC chip are transmitted to the NFC reader.

[0062] Specifically, after NFC communication begins, the NFC reader sends a radio frequency signal to activate the NFC chip 210 in the mobile terminal protective shell 10 through the NFC antenna 100. After activation, the NFC chip 210 transmits the stored access control credentials to the NFC reader through wireless communication.

[0063] S16. The NFC reader decodes the access control credentials received from the NFC chip to obtain identification information, and transmits it to the access control system to determine whether the identification information matches the reference information in the target database.

[0064] S17. If the identification information matches the reference information, the access control system sends an unlocking signal to the electric lock, the electric lock is unlocked, and the verification is successful; if the identification information does not match the reference information, the electric lock remains closed.

[0065] Specifically, the NFC card reader receives the access control credentials (eg, encrypted identity information) in the NFC chip 210 .

[0066] The NFC reader decodes the received information and transmits it to the access control system for further authentication. The access control system receives the access control credential information from the NFC reader and verifies it.

[0067] The access control system can use a target database, such as an internal database or a cloud database, to match the credential information and verify the authenticity of the user's identity. For example, if the access control credential contains an encryption key, the system will decrypt and verify it. At this time, the display screen 300 will display the access control status and related information, such as "Authorized" or "Unauthorized". Once the identity is verified, the access control system will send an unlock signal to the electric lock. After receiving the unlock signal from the access control system, the electric lock will activate the mechanical unlocking device to allow the user to enter. After the user passes, the electric lock will automatically relock and wait for the next trigger.

[0068] S18. Control the mobile terminal protective shell to move away from the NFC reader until the near field communication between the NFC reader and the mobile terminal protective shell is disconnected, and the access control system and the NFC chip stop exchanging data.

[0069] S19. The access control system records the user's leaving record and updates the access log, and resets the access control system to the initial state.

[0070] S20: The electric lock is relocked and the display shows the current access control status or static information.

[0071] Specifically, when the user's mobile terminal moves away from the NFC reader, NFC communication is automatically disconnected. At this point, the NFC reader no longer detects the user's NFC device, and the system terminates data transmission to ensure communication security. After NFC communication is disconnected, the access control system returns to its initial state and waits for the next user. At this time, the display 300 displays the corresponding information after receiving the control signal. After the user completes access control verification, status information such as "Passed" or "Rejected" can be displayed. The current display content remains after the user leaves, because the display 300 does not require continuous power to retain static information.

[0072] In one embodiment, the method for updating the wallpaper of the display screen 300 of the mobile terminal protective case 10 of the present application includes: when a user brings the mobile terminal close to the NFC area of ​​the mobile terminal protective case 10, the mobile terminal NFC antenna automatically senses and attempts to activate the NFC chip 210 on the mobile terminal protective case 10. When the mobile terminal NFC antenna detects the mobile terminal protective case 10 containing the NFC chip 210 on the other end, the two parties begin to establish communication. The mobile terminal NFC antenna of the smartphone transmits energy and data to the mobile terminal protective case 10.

[0073] After the NFC chip 210 of the mobile terminal protective shell 10 receives the data, the data packet will be decoded. This data is usually the pattern or text information selected by the user on the target application. The NFC chip 210 transmits the decoded information to the display screen 300 control circuit, and the display screen control circuit is adapted with N-channel MOS (NMOS), so that the NMOS can adjust the current according to the driving resistance, so that the display screen 300 can display the complete pattern or information, that is, to ensure that the display screen can work normally, and after sending the custom initialization instruction to the control circuit of the display screen 300, the control circuit and the specific parameters of the display screen 300 can be matched, at this time, the control circuit updates the display content of the display screen 300 accordingly. The initialization instruction only needs to be sent once after the configuration is completed, even if the display screen is not replaced, it does not need to be sent repeatedly, because the initialization instruction only takes effect when the device starts or initializes, and once the configuration is complete, the driving circuit will always run according to the setting, without the need for repeated sending, so that the display screen 300 can maintain the display content after the update is completed, without consuming additional power. After the display update is completed, the NFC chip 210 of the mobile terminal protective shell 10 usually sends a feedback signal to the mobile terminal to confirm that the data has been successfully transmitted and displayed, and the pattern or data update of the display screen 300 is completed; in addition, the mobile terminal protective shell 10 of the present application can update the pattern or text information of the display screen 300 while controlling the access control to open, without affecting the opening of the access control.

[0074] The present application integrates the NFC chip 210 containing access control credential information in the mobile terminal phone shell, so that the mobile terminal protective shell 10 has the access control function, so that the mobile terminal protective shell 10 can be used to contact or approach the access control device to open the access control, reduce the risk of illegal access, thereby improving the security of the access control system, and without the need to carry the traditional access control card, improving the convenience; in addition, the NFC antenna 100 is located in the area close to the mobile terminal NFC antenna, so as to shorten the distance between the NFC antenna 100 and the mobile terminal NFC antenna, reduce the risk of signal attenuation, thereby improving the reliability of NFC communication.

[0075] The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the specification and drawings of the present application, such as the mutual combination of technical features between embodiments, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A mobile terminal protective case, characterized in that: It includes an NFC antenna, a display mainboard, a display screen and a shell, wherein the NFC antenna, the display mainboard and the display screen are arranged on the shell, and a camera through-hole is provided in the top area of ​​the shell near the shell, the NFC antenna is located on the side of the camera through-hole and is arranged opposite to the NFC antenna of the mobile terminal, the display mainboard is located on the side of the camera through-hole and the bottom of the camera through-hole, the display mainboard is located on the side of the display mainboard away from the NFC antenna and the camera through-hole, the NFC antenna is electrically connected to the display mainboard, the display mainboard is electrically connected to the display screen, the NFC antenna is used to receive signals from an NFC reader, the display mainboard includes an NFC chip containing access control credential information, the NFC chip is used to receive and process signals from the NFC antenna, the display screen is used to display relevant information, and the NFC antenna is formed by winding a wire.

2. The mobile terminal protective case according to claim 1, characterized in that: The display mainboard also includes an NFC pad and a circuit board. The NFC pad is connected to the NFC antenna and the NFC chip respectively. The NFC chip is located on the side of the NFC pad away from the NFC antenna. The circuit board is located on the side of the NFC chip away from the NFC chip. The circuit board is used to process and transmit data.

3. The mobile terminal protective case according to claim 2, characterized in that: The display mainboard further includes a circuit pad for connecting to the display screen, and the circuit pad is located on a side of the circuit board away from the NFC chip.

4. The mobile terminal protective case according to claim 1, wherein: The NFC chip contains a rectifier circuit for converting the alternating current received by the NFC antenna into a direct current.

5. The mobile terminal protective case according to claim 4, characterized in that: The rectifier circuit includes a shaping circuit module, a voltage stabilizing circuit module, a first control circuit module, a second control circuit module, and a filtering and energy storage circuit module. The shaping circuit module is connected to the voltage stabilizing circuit module and the first control circuit module, the first control circuit module is connected to the filtering and energy storage circuit module, and the first control circuit module is connected to the second control circuit module. The shaping circuit module is used to rectify the alternating signal, the voltage stabilizing circuit module is used to limit the output voltage, the first control circuit module is used to control the output voltage stability, the second control circuit module is used to amplify the input current and control the switch of the first control circuit module, and the filtering and energy storage circuit module is used for filtering.

6. The mobile terminal protective case according to claim 5, characterized in that: The shaping circuit module includes a first Schottky diode, a second Schottky diode, a third Schottky diode and a fourth Schottky diode. The first input end of the NFC chip is respectively connected to the anode of the first Schottky diode and the cathode of the second Schottky diode, the second input end of the NFC chip is respectively connected to the cathode of the third Schottky diode and the anode of the fourth Schottky diode, and the anode of the second Schottky diode and the anode of the third Schottky diode are both grounded.

7. The mobile terminal protective case according to claim 5, characterized in that: The voltage stabilizing circuit module includes a voltage stabilizing diode, a cathode of the voltage stabilizing diode is connected to the output end of the shaping circuit module, and an anode of the voltage stabilizing diode is grounded.

8. The mobile terminal protective case according to claim 5, characterized in that: The first control circuit module includes a P-type channel field effect transistor, a first resistor and a second resistor. The source of the P-type channel field effect transistor is connected to the output end of the shaping circuit module, the first ends of the first resistor and the second resistor are connected to the source of the P-type channel field effect transistor, the second end of the first resistor is connected to the drain of the P-type channel field effect transistor, and the second end of the second resistor is connected to the gate of the P-type channel field effect transistor.

9. The mobile terminal protective case according to claim 8, characterized in that: The second control circuit module includes an N-type channel field effect transistor and a third resistor, the drain of the N-type channel field effect transistor is connected to the gate of the P-type channel field effect transistor, the source of the N-type channel field effect transistor is grounded, the third resistor is connected to the gate of the N-type channel field effect transistor, and the gate of the N-type channel field effect transistor is used to input a control signal.

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