NFC-based ink screen mobile phone shell power supply and refresh control system

Abstract

The application provides an ink screen mobile phone shell power supply and refresh control system based on NFC. The system comprises an NFC power receiving and communication component, an energy management component, a control and driving component and an electronic ink display module. The NFC power receiving and communication component induces an alternating magnetic field emitted by a mobile terminal to obtain alternating current energy and modulated image data signals; the energy management component converts the alternating current energy into direct current energy and stores the energy, and provides working voltage to the system in stages; the control and driving component receives signals and decodes them when preset triggering conditions are met, and outputs pixel driving waveforms; the electronic ink display module displays picture refresh according to the pixel driving waveforms, and relies on the bistable characteristics of microcapsules to power off and keep the picture after refresh. The system realizes picture refresh under the condition of no built-in independent power supply, and avoids forming interference load on the original NFC high-frequency service of the mobile terminal.

Description

Technical Field

[0001] This invention relates to the field of smart terminal accessories and near-field communication technology, and in particular to a power supply and refresh control system for an NFC-based e-ink screen phone case. Background Technology

[0002] Currently, with the widespread adoption of smart mobile devices, users' functional demands for phone cases are increasing, and phone cases with display modules are gradually becoming a focus of market attention. Conventional smart peripherals with display modules typically have a built-in independent battery for power or connect to the mobile device via a physical data cable. The built-in battery design increases the overall thickness and weight of the peripheral, and requires users to replenish it regularly, leaving room for improvement in ease of use. Using a physical interface connection, on the other hand, occupies the mobile device's data interface for extended periods, affecting users' regular wired charging or data transfer operations.

[0003] The development of near-field communication (NFC) technology has provided a technical solution for contactless data and energy transfer between smart devices. Applying NFC technology to mobile phone cases to achieve data and energy transfer is feasible. However, in practical engineering applications, mobile terminals often integrate native high-frequency antennas for payment or public transportation card services on the back. If the receiving coil of an external device is directly connected to the antenna circuit without restriction, it may change the overall resonant frequency of the system and generate unnecessary load effects when the mobile terminal performs native high-frequency services.

[0004] In addition, many modern mobile terminals are equipped with wireless charging receiving coils for energy transfer and magnet arrays for positioning. If the external display component has a large continuous metal structure or uses conventional high-permeability materials in the relevant area, it is prone to generating macroscopic closed eddy currents in alternating magnetic fields, leading to heat loss. This can affect the normal operation of wireless charging or alter the original magnetic field path, causing a shift in the positioning accuracy of the external device. How to maintain the normal operation of the mobile terminal's original radio frequency and magnetic functions while acquiring electromagnetic energy and communication data is a current technical challenge in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to provide a power supply and refresh control system for e-ink screen mobile phone cases based on NFC. The purpose of this invention is to solve the technical problem that external display devices without independent power supplies can easily interfere with the native communication services of mobile terminals when using near-field communication to obtain energy and data, and simultaneously overcome the technical defects that peripheral structural components may affect the wireless charging and magnetic alignment functions of mobile terminals.

[0006] This invention provides an NFC-based power supply and refresh control system for e-ink screen phone cases, comprising: An NFC power receiving and communication component is disposed inside the phone case and close to the NFC sensing area of ​​the mobile terminal, and is used to sense the alternating magnetic field emitted by the mobile terminal to obtain alternating electrical energy and modulate image data signals. An energy management component, electrically connected to the NFC power receiving and communication component, is used to convert the AC power into DC power and store the energy to provide operating voltage to the system in stages. A control and drive component, electrically connected to the energy management component and the NFC power receiving and communication component respectively, is used to receive and decode the modulated image data signal when a preset trigger condition is met, and output a pixel drive waveform based on the decoded image data; and An electronic ink display module is electrically connected to the control and drive components, used to refresh the display based on the pixel drive waveform, and retain the display after power-off due to the bistable characteristics of the microcapsules after the refresh is completed; The NFC power receiving and communication component enters the receiving response state only when the preset trigger condition is met, so as to avoid interference load on the native NFC high-frequency service of the mobile terminal and achieve service isolation.

[0007] Optionally, the energy management component includes a rectifier circuit, a voltage regulator circuit, and an energy storage unit connected in sequence. The rectifier circuit is used to rectify the alternating current energy generated by the alternating magnetic field into direct current energy. The voltage regulator circuit is used to step down and regulate the DC power. The energy storage unit is used to temporarily store the regulated DC power, and after the voltage reaches a set threshold, it supplies power to the control and drive components and the electronic ink display module according to a preset timing sequence.

[0008] Optionally, the energy storage unit uses a microcapacitor or a supercapacitor, and the energy management component further includes a low voltage detection circuit; The low-voltage detection circuit is used to monitor the charge of the microcapacitor or the supercapacitor in real time to avoid the impact of instantaneous power supply fluctuations on the refresh stability of the electronic ink display module.

[0009] Optionally, the control and drive components include a low-power controller and an image buffer unit; The low-power controller is used to receive the modulated image data signal packet by packet under close-range conditions, and sequentially complete frame header identification, address identification, packet reassembly, verification and confirmation, and image decoding.

[0010] Optionally, the control and drive component adopts a segmented refresh logic, that is, after receiving and partially caching the data of one image partition in the image cache unit, the pixel drive waveform is output to the electronic ink display module in the order of the regions to reduce the single peak power supply pressure.

[0011] Optionally, the preset triggering conditions include limiting a specific instruction set response or limiting a coil coupling window; By using the preset triggering conditions, the system does not respond to unauthorized high-frequency scanning signals, thus ensuring compatibility with the mobile terminal's native payment and transportation card services.

[0012] Optionally, the inside of the phone case body is also provided with a magnetic device mounting area and a wireless charging avoidance area; The metal cover of the control and drive components adopts a metal clearance structure in the area corresponding to the wireless charging coil of the mobile terminal to reduce eddy current losses generated by the high-frequency magnetic field, thereby maintaining the normal operation of the wireless charging and magnetic alignment functions of the mobile terminal.

[0013] Optionally, a transparent protective layer is stacked on the outside of the electronic ink display module, and the mobile phone case body also includes an outer shielding PET layer and an inner magnetic PET layer; The transparent protective layer remains fully transparent in the corresponding display window area, and in the non-display area, it combines with the shielding PET layer to cover the internal components.

[0014] Optionally, the modulated image data signal is generated and modulated by an application terminal located within the mobile terminal; The application performs size adaptation and color mode mapping on the content to be displayed, and packages the content into a data packet suitable for NFC bandwidth and power limitations through an image compression algorithm.

[0015] Optionally, after the screen refresh is completed, the energy management component stops outputting power to the control and drive component, and the system enters a zero standby power consumption state.

[0016] The present invention has achieved the following beneficial effects: This invention, by incorporating an energy management component and a control and drive component that only enters a response state upon meeting preset trigger conditions, enables the e-ink screen phone case to acquire power and refresh images using the alternating magnetic field radiated by the mobile terminal without an independent power supply. After the image refresh is complete, the system maintains the image even after power loss due to the bistable characteristics of the e-ink display module, thus entering a zero standby power consumption state. Simultaneously, it avoids interfering with the mobile terminal's native high-frequency services. The system employs a metal clearance structure in the area corresponding to the mobile terminal's wireless charging coil and uses a low-permeability composite material layer as a physical separator for the magnetic array area, effectively reducing eddy current losses generated by the high-frequency magnetic field and maintaining the normal operation of the mobile terminal's wireless charging and magnetic alignment functions.

[0017] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a block diagram showing the overall physical architecture of the system and the interaction and connection relationships of its components according to the present invention. Figure 2 This is a schematic diagram of the layered cross-section of the back of the mobile phone protective case body from the inside to the outside in this invention; Figure 3 This is a circuit topology block diagram of the hardware electromagnetic energy acquisition and control drive in this invention; Figure 4 This is a logic flowchart of the phased power supply and preset timing start control of the system in this invention; Figure 5 This is a flowchart of the image data dimensionality reduction adaptation and compression distribution for mobile terminal applications in this invention; Figure 6 This is a flowchart of the passive screen refresh ultimate interaction and high-frequency status polling mechanism in this invention. Detailed Implementation

[0020] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0021] At the overall physical architecture level, such as Figure 1 As shown, this NFC-based e-ink screen phone case power supply and refresh control system uses the phone case itself as the basic physical carrier and packaging platform. The phone case not only serves to wrap and protect the mobile terminal, but also highly integrates multiple functional hardware components within its multi-layered composite structure. Specifically, the system includes NFC power receiving and communication components, energy management components, control and drive components, and an e-ink display module. These components, through a specific physical spatial layout and electrical connections, collectively achieve a complete technical chain for energy acquisition, data parsing, and image refresh, relying solely on the alternating magnetic field radiated by the mobile terminal's near-field communication antenna, without the need for any independent chemical batteries or external wired power supply.

[0022] Regarding the materials and layered structure of the phone case body, to meet the multi-dimensional engineering requirements of the device in terms of mechanical protection, optical display, electromagnetic isolation, and aesthetic decoration, its shell frame adopts a composite injection molding process combining an inner frame and an outer frame. Specifically, the outer frame is made of thermoplastic polyurethane elastomer soft rubber material (TPU) to provide preset edge impact buffer deformation. Its surface is fully glossy, presenting a semi-transparent or solid color state in specific configurations. The color attribute can be set to specific color values ​​such as orange or black according to manufacturing parameters. The inner frame is made of polycarbonate hard rubber material (PC), cut and formed by computer numerical control machine tools, with a molded textured surface and high-gloss treatment in some areas to provide the high-rigidity support structure required for the assembly of internal components. On the back of the phone case body, such as Figure 2 As shown, the following layers are stacked sequentially from the inside to the outside along the thickness direction: an inner frame, a main board and flexible connector, a magnetic PET layer, a shielding PET layer, an electronic ink display module, and a transparent protective layer. The transparent protective layer is a lens structure with a specific light transmittance, made of polyethylene terephthalate (PET) or polycarbonate (PC), with a thickness of 0.35mm or 0.25mm in specific embodiments. This transparent protective layer remains fully transparent in the display window area corresponding to the electronic ink display module to ensure undamaged optical image transmission. In non-display areas, a composite processing technique is used, including partial surface matte treatment, surface glitter sandblasting, screen-printed display area borders, and solid-color back printing, to achieve visual shielding and physical protection of the internal printed circuit board, traces, and induction coils. Both the shielding PET layer and the magnetic PET layer use composite boards of specific thicknesses, with a matte finish on their outer surfaces and a base color of silver or dark gray, used to define specific electromagnetic operating areas and physical isolation zones. The top auxiliary structure of the phone case also includes a top cover component manufactured using injection molding. The inner ring of the frame is treated with a high-gloss C-side, while the remaining areas use a spark texture labeled 27 to enhance the structural continuity of the assembly interface.

[0023] In the specific production and assembly process of the system components, the physical joining steps of each component follow strict mechanical and electrical process specifications. The specific assembly sequence is as follows: First, precision adhesive is applied to a specific groove on the inner side of the protective casing. Then, a magnet is precisely embedded into the casing and constant pressure is applied for pressure holding and curing. Next, in the electrical component assembly stage, the manufacturing equipment firmly connects the lead terminals of the NFC receiving coil to the power supply pads of the motherboard using a soldering process. Subsequently, the motherboard body with components is embedded into a pre-set cavity at the bottom of the protective casing for fixation. At the same time, a large area of ​​the receiving coil is laid flat on the protective casing, and the flexible connecting wires between the two are carefully straightened and tightly bonded and fixed to the inner shell of the protective casing using an adhesive process. On this basis, adhesive is applied to the edge of the display window area, the electronic ink display module and the LCD transparent protective lens above it are embedded in place, and a second pressure holding is performed. Finally, for the openings in non-display areas such as the rear camera, adhesive is applied and corresponding camera decorative parts or protective lenses are installed, completing the final pressure holding and sealing of the entire device.

[0024] In the acquisition and conversion of electromagnetic energy, such as Figure 3 As shown, the NFC receiving and communication component undertakes the fundamental task of converting spatial electromagnetic waves into usable electrical energy and raw data streams. The core of this component includes a receiving coil, an impedance matching network, and an NFC communication unit. Spatially, the receiving coil is positioned inside the phone case and aligned with the NFC sensing area on the back of the mobile terminal, typically near the bottom of the top camera module. This layout ensures that the physical distance between the receiving coil and the transmitting antenna inside the mobile terminal is kept within 3cm, thereby maximizing the magnetic flux coupling coefficient. When the mobile terminal's NFC module is activated and radiates a high-frequency alternating magnetic field with a working frequency of 13.56MHz, the receiving coil generates a high-frequency induced electromotive force by cutting the alternating magnetic field lines. The impedance matching network, through a precisely configured array of capacitors and inductors, adjusts the resonant impedance of the receiving coil at 13.56MHz to match the input impedance of subsequent circuits. Specifically, the equivalent input impedance of the subsequent rectification and voltage regulation circuit After calculation, it is fixed at to Within the real number interval. Therefore, the impedance matching network adopts an L-shaped matching topology, which internally consists of parallel resonant capacitors. With series regulating capacitor Composition. The parameter solution process is based on the classic Smith chart and the resonance equation: ; In the above resonance equation, This represents the system's operating frequency and resonant center frequency, specifically referring to the center frequency of near-field communication. ; Represents the constant value of pi; This represents the inherent inductance of the receiving coil after it has been actually wound and bonded. Represents a parallel resonant capacitor Series regulating capacitor And the overall equivalent capacitance value after the combined effect of the distributed parasitic capacitance of the printed circuit board.

[0025] In the specific configuration, the measured inherent inductance value of the receiving coil is controlled within... to Within the range, the parallel capacitor can be derived by reverse calculation using the above formula. The range of values ​​for is precisely defined as to Series capacitor The range of values ​​for is defined as follows: to By fine-tuning the impedance element within this range, it can be ensured that... The system achieves conjugate matching within its bandwidth to reduce RF energy reflection loss at the interface.

[0026] Since the receiving coil outputs an AC signal with a high-frequency carrier wave, it cannot directly drive DC electronic components. Therefore, the energy management component is configured to perform deep rectification and voltage regulation of this electrical energy. The energy management component is electrically connected to the NFC receiving and communication component and internally includes a rectifier circuit, a voltage regulator circuit, and an energy storage unit. The rectifier circuit converts the high-frequency AC power into pulsating DC power. In the specific hardware configuration, the rectifier circuit uses a PSB521S-40 Schottky barrier diode to construct a bridge rectifier structure. This Schottky diode uses an SOD-523 ultra-small surface-mount plastic package, has a reverse withstand voltage of 40V, and a forward voltage drop of only 0.58V under a 200mA forward current condition. Its ultra-low forward voltage drop characteristic greatly reduces heat loss in the rectification stage and improves the overall energy conversion efficiency of the system. Meanwhile, to prevent the high-voltage pulse generated by the instantaneous strong coupling of NFC from damaging the subsequent circuitry, a silicon planar Zener diode, such as the MM3Z5V6 Zener diode in an SOD-323 package, is connected in parallel at the output of the rectifier circuit. This Zener diode has a nominal voltage regulation value of 5.6V and a maximum power dissipation capability of 300mW. When an abnormal spike occurs in the rectified output voltage and exceeds 5.6V, this diode quickly enters a snow peak breakdown state, forcibly clamping the voltage within a safe range and protecting the subsequent precision control chip.

[0027] Subsequently, the voltage regulator circuit filters and levels the pulsating DC current, outputting a DC voltage with constant amplitude. In the specific implementation of the voltage regulator circuit, the system uses the ETA8120 high-efficiency synchronous buck converter chip. This chip uses an SOT23-6 package, supports a wide input voltage range of 4.5V to 18V, has a maximum current output capability of 2A, and integrates an ultra-low on-resistance power MOSFET. The ETA8120 employs an adaptive constant on-time (COT) control architecture, enabling operation at a fixed switching frequency of 600kHz without the need for an external compensation network. Under light-load conditions requiring instantaneous power supply to the NFC system, the chip automatically switches to pulse frequency modulation (PFM) mode, reducing its no-load quiescent current to 177uA, further saving switching losses. In this buck topology, the chip's switching node (SW) is connected to an external 2.2uH inductor, and the feedback node (FB) samples the voltage through a precision voltage divider network of 91K ohms and 20K ohms, amplifying the internal 0.6V reference voltage according to a preset ratio, thereby stably outputting a 3.3V DC operating voltage at the output terminal, providing a reliable power rail for the entire digital logic circuit.

[0028] The output of the voltage regulator circuit is electrically connected to the energy storage unit, which consists of an array of miniature capacitors or supercapacitors with a specific capacitance value. The exact range of this specific capacitance value is derived through a system limit energy model. It is known that the time consumed in a single full-screen refresh cycle of the electronic ink display module is... to The corresponding maximum energy consumption is calculated as follows: to According to the capacitor energy storage formula: ; In the above formula for capacitor energy storage, This represents the maximum total energy consumption of an electronic ink display module within a single full-screen refresh cycle. This represents the exact total capacitance value when a microcapacitor or supercapacitor array acts as an energy storage carrier. This represents the upper limit of the DC operating voltage output by the voltage regulator circuit and applied to both ends of the energy storage unit. This represents the minimum threshold operating voltage required to ensure the normal operation of digital logic circuits and low-power controllers.

[0029] Set the upper limit voltage of the regulated output. for The minimum sustaining voltage to ensure the operation of logic circuits for Substituting the peak requirement of the maximum energy consumption into the formula, the exact total capacitance range of the microcapacitor or supercapacitor array must be set within a certain range. to Between these values. This capacitance range physically ensures that even in the event of a momentary interruption of the external alternating magnetic field, the energy released by the capacitor is sufficient to support a complete closed-loop screen refresh operation.

[0030] To address power fluctuations during NFC instantaneous power supply, where the system's peak power typically fluctuates between 0.1mW and 0.5mW, the energy management component incorporates a low-voltage detection circuit. Specifically, this detection circuit utilizes a low-voltage detector chip from the HX61CXX series, such as the HX61C33N model. This chip is manufactured using CMOS technology, with a typical static power consumption of only 2.0uA and supports an operating voltage range of 1.5V to 12V. Internally, it integrates a high-precision voltage comparator and a reference voltage source. The HX61C33N only flips its N-channel open-drain or CMOS output state, outputting a valid system reset or enable signal, when the terminal voltage within the energy storage unit rises and stabilizes above a threshold of 3.3V. This threshold-controlled, phased power supply mechanism fundamentally avoids the abnormal situation where the system controller repeatedly restarts or the display module refreshes interrupted due to the instantaneous decay of the mobile terminal's electromagnetic field strength under low-voltage conditions. Furthermore, as... Figure 4 As shown, the preset timing is specifically configured to include three startup flows with hard logic delays. The first stage: The HX61C33N detects a voltage spike at the capacitor terminal. Upon reaching the threshold, a high-level reset release signal is immediately sent to the low-power controller; in the second stage, after receiving this signal, the controller starts an internal timer to force a delay. to (Used to wait for the internal crystal oscillator circuit to reach stable oscillation), then pulls the corresponding general purpose input / output (GPIO) pin high to power the underlying digital communication circuit, causing the NFC communication unit to enter carrier listening state; Third stage: Only when the NFC communication unit successfully demodulates two consecutive valid protocol frame headers (such as 0xF00xD2) from the carrier is it determined that a legitimate service request has been received, and the system proceeds accordingly. An internal pulse-width modulation (PWM) drive waveform is output to turn on the high-power MOSFET to deliver peak drive current to the e-ink display module. This strict timing condition determination avoids unnecessary consumption of static power.

[0031] In the data parsing and logic execution phase, the control and drive components are equipped with a low-power controller, an image buffer unit, and an e-ink screen drive unit. When the low-voltage detection circuit releases the enable signal, the system establishes a stable power supply connection. The NFC communication unit demodulates the baseband data stream from the 13.56MHz carrier signal and transmits it to the low-power controller. This controller is equipped with a hardware decoding coprocessor and protocol parsing logic, responsible for performing frame header recognition, address matching, data verification, packet reassembly, and final image matrix restoration on the received data packets. For the restored image matrix, the low-power controller temporarily writes it to the image buffer unit. Subsequently, the control logic initiates the pixel driving process. In the specific pixel driving process, the segmented refresh logic used by the control and drive components has the following internal extraction steps and associated mapping relationships: The system determines the total number of gate drive coils vertically distributed on the target screen (assuming a total vertical resolution of 1). (Line), divide the entire image into uniformly high basic image partitions (e.g., strictly according to each) (Rule-based partitioning of behavior-based partitions). Its data flow is as follows: whenever the controller's image buffer unit accumulates full data... After receiving valid pixel data, the local RAM area is immediately locked. Then, the controller scans the table according to the exact region order from the top gate to the bottom gate of the screen (from Row0 to RowM-1), and sends the currently ready local drive waveform to the source driver of the display module. During this first partition refresh operation, the system's UART / SPI communication interface receives the message stream of the next partition in parallel, thus forming a steady-state mapping relationship of block buffering-sequential discharge-waveform rolling, avoiding transient peak current exceeding limits caused by simultaneous charging and discharging of all screen pixel units. To achieve zero-power-down retention after refresh and precise power timing cut-off during refresh, the control and drive components employ a discrete load switching network. This network consists of a combination of P-channel and N-channel MOSFETs. Specifically, the cut-off of the main power supply path is performed by a single P-channel power MOSFET of model WPM02140E. This device uses an SOT-23 package, has a withstand voltage of -20V, and a maximum on-resistance of only 49mΩ at a gate-source voltage of -4.5V, which greatly reduces the voltage drop loss when the drive circuit is turned on. Meanwhile, the level shifting and weak signal switching control of the underlying logic circuit are handled by N-channel MOSFETs of the 2N7002KL or JST3400 model. The 2N7002KL has a drain-source breakdown voltage of 60V and a low on-resistance of 3.0Ω, with a switching delay in the nanosecond range (25ns on-delay, 35ns off-delay), suitable for high-frequency pulse width modulation (PWM) signal transmission. The JST3400 has a withstand voltage of 30V and an extremely low on-resistance of 33mΩ, responsible for driving high-current peripheral auxiliary circuits. Through the precise coordination of these discrete switching devices, the system achieves transient high-current supply during the refresh phase and absolute physical disconnection during the static holding phase.

[0032] The electronic ink display module is electrically connected to the output of the control and drive components. As the physical display carrier, it receives the pixel drive waveform and completes the final image rendering. The core working area of ​​the module consists of a dense array of micron-sized microcapsules, each with a diameter similar to a human hair, containing charged pigment particles suspended in a transparent or dyed liquid. In a basic two-color configuration, the microcapsules contain positively charged white particles and negatively charged black particles; in a multi-color configuration, they contain red, yellow, green, or blue particles with different electrophoretic mobility and charge characteristics. When the pixel drive waveform is applied to the electrodes of a specific pixel unit through a thin-film transistor (TFT) circuit, a local DC electric field is formed inside the microcapsule. Under the action of this electric field, pigment particles with specific polarities undergo directional electrophoretic migration. For example, a positive electric field drives positively charged white particles to float to the display surface, while a negative electric field drives negatively charged black particles to float to the display surface, thus macroscopically presenting a specific pixel color. The refresh process of this electronic ink display module is configured for a specific time period of 2 to 5 seconds. Once the refresh cycle ends and all particles within the microcapsules have reached their target positions, the control logic of the energy management component will actively cut off the gate drive signal of the load switch MOSFET, ceasing to maintain power output to the display module. At this point, relying on the physical properties of the fluid inside the microcapsules and the charge characteristics of the pigment particles themselves, the system can maintain the current image display for several months even when power is off with a power consumption of 0mW.

[0033] Furthermore, to resolve the severe conflict between this system and the native electromagnetic radio frequency functions of mobile terminals during actual operation, the system incorporates deep isolation and compatibility mechanisms at both the hardware structure and communication logic levels. It is known that mobile terminals not only have built-in native NFC antennas for Apple Pay or public transportation card services, but also receive coils for wireless charging and magnet arrays for magnetic positioning. If the circuit network and metal structure of this system do not avoid these functional areas, physical interference will occur.

[0034] First, regarding the compatibility configuration of wireless charging frequency bands. Wireless charging relies on a low-frequency alternating magnetic field (110kHz to 205kHz) between the charging transmitter and the receiving coil inside the mobile terminal for energy transfer. If the phone case contains a large area of ​​continuous conductive metal layer (such as the metal backplate of a display module), this low-frequency alternating magnetic field will induce strong closed eddy currents within the metal layer. The presence of these eddy currents not only causes up to 30% to 50% of the electromagnetic energy to be converted into useless heat, resulting in a drop in actual received power from 15W to 4W to 6W, and a decrease in charging efficiency to 27% to 40%, but also triggers an abnormal temperature rise of +15°C. This can easily trigger the mobile terminal's internal warning temperature threshold of 35°C, the frequency reduction charging threshold of 40°C, and even the 45°C charging stop thermal protection threshold, causing the charging process to be forcibly terminated by the system. To eliminate this eddy current loss effect, this system adopts a low-metal coverage or completely metal-avoided structure design in the area of ​​the phone case corresponding to the mobile terminal's wireless charging coil, i.e., the wireless charging avoidance zone. Specifically, the printed circuit board of the control and drive components is cut out in this area, and the related conductive traces are laid out in a grid pattern to cut off the macroscopic closed loop formed by eddy currents and ensure that the low-frequency magnetic flux of wireless charging can penetrate the protective sleeve body.

[0035] Secondly, regarding the compatibility configuration of the magnetic positioning system. The ring-shaped magnet array inside the mobile terminal typically contains 18 neodymium magnets for precise physical alignment and stable adsorption with the external charger. If the protective case body uses a metal driving layer material with a high relative permeability (e.g., 200 to 5000), it will severely divert the original magnetic field path of the mobile terminal, causing the magnetic attraction force of the external magnetic device to decrease by 40% to 60%. This will lead to an alignment accuracy shift from ±0.5mm in the bare state to ±5.0mm, ultimately causing the charger's NFC reader to fail to recognize accessory information and forcibly limiting the charging power to below 5W. To address this, this system designs a dedicated magnetic PET layer inside the phone case body. This layer has a pre-reserved area in its physical structure for mounting magnetic devices that align with the mobile terminal's magnet array, and uses a low permeability composite material with a relative permeability between 1.0 and 1.1 (close to the permeability of air, 1.0) for physical separation. The relevant control circuits and electronic ink microcapsules (with a relative permeability of about 1.2 to 1.5) are all confined within a reasonable spatial structure to ensure the spatial integrity of the magnetic field line distribution.

[0036] The core physical conflict lies in the coexistence of native NFC services in the 13.56MHz band. The mobile terminal's native NFC antenna and the system's external receiving coil are physically close, typically less than 2mm thick, resulting in a strong electromagnetic coupling coefficient greater than 0.7. Under normal conditions, if the system's receiving coil is indiscriminately responding, when the mobile terminal performs a payment operation, the external receiving coil will act as a parallel load connected to the native antenna circuit. This causes the overall resonant frequency of the system to split, generating dual resonant peaks f1 and f2, resulting in a signal attenuation exceeding 20dB at the 13.56MHz center frequency. Simultaneously, the impedance change of the system's external antenna completely destroys the mobile terminal's data reflection capability based on load modulation, causing the field strength to plummet from -35dBm to -55dBm, reducing the communication success rate to below 10%, and paralyzing the payment system. To resolve this underlying physical conflict, the system incorporates preset trigger conditions and state machine isolation logic in the control and drive components, as well as the NFC receiving and communication components.

[0037] Specifically, the preset triggering conditions are configured to limit specific instruction set responses or limit coil coupling windows, etc.

[0038] Specifically, the logic determination regarding the limited coil coupling window refers to extracting the time-domain envelope slope of the RF front-end induced voltage using an analog-to-digital converter (ADC). The specific logic determination condition is: the system uses... The reference voltage after rectification is sampled continuously at a fixed frequency, if and only if the sampled voltage is continuously... The absolute amplitude remains within the sliding time window The above conditions apply, and the rate of change of its voltage gradient satisfies the following criterion: ; In the region of the above judgment formula, The rate of change of the time-domain envelope gradient of the induced voltage; This represents the absolute value of the voltage amplitude difference between two adjacent ADC sampling points within a preset sliding time window; This represents the time step difference between two adjacent ADC sampling points.

[0039] Any voltage spike that is steep and pulse-like or lasts less than Field strength fluctuations at the threshold are all filtered out as illegal dynamic scanning interference, thereby preventing the underlying hardware from entering the receiving response state.

[0040] By default, the RF front-end circuit of the NFC receiving and communication components does not generate a load effect from external magnetic fields. Only when the application inside the mobile terminal initiates a dedicated image refresh mode will the application wake up the NFC channel via a specific command. Although the system has strong physical coupling, it achieves service isolation in terms of logical links and impedance performance. This ensures that when a user touches the gate with their mobile terminal, the protective cover does not cause interference to the native high-frequency near-field communication service.

[0041] In terms of the organizational structure and operation mechanism of the data transmission protocol, this system adopts a strictly defined set of Application Protocol Data Unit (APDU) specifications to ensure the error-free delivery of image data in low-energy environments. The data interaction between the mobile terminal application and the control and drive components of this system is built based on the ISO / IEC 14443 physical layer protocol and the ISO / IEC 7816-4 application layer instruction architecture.

[0042] The command APDU frame structure at the data link layer is defined as a multi-byte ordered sequence. The first byte of the sequence is the instruction class field (CLA), typically 0x00, 0x80, or 0xF0; the second byte is the instruction code field (INS); the third and fourth bytes are the parameter fields (P1, P2); the fifth byte is the data field length field (Lc); and the end of the sequence is the data field (Data), with the maximum data size per packet limited to 250 bytes (0xFA). The response APDU frame structure contains optional response data and ends with two mandatory status bytes (SW1 and SW2) to report the execution status to the mobile terminal.

[0043] Before officially initiating the image transmission process, the mobile terminal application sends a specific instruction to the control and drive component to read the device configuration. This instruction sequence is: 00 D1 00 00 00. Upon receiving this instruction, the control and drive component returns a set of hardware parameters based on the Tag-Length-Value (TLV) data format. The configuration data includes a screen basic information field with the tag 0xA0, with a length of 0x07. Internally, arranged in big-endian order, it contains a 1-byte manufacturer code, a 1-byte flip configuration, a 1-byte color quantity parameter, and 1-byte parameters for the screen's physical height, height, width, and width. Bits 7 and 6 of the flip configuration bit indicate the horizontal or vertical flip state. The configuration data also includes the number of images (tag 0xB1), the power supply mode (0xB3, 01 for active, 00 for passive), the application identifier (AppID) (0xC0), the universally unique identifier (UUID) (0xC1), the compression mode and version number (0xD1), and the color configuration (0xE0) for multi-color screens.

[0044] After obtaining the physical parameters, such as Figure 5 As shown, the application initiates image dimensionality reduction and adaptation algorithms. Addressing the color limitations of e-ink screens, the application is configured with the Atkinson dithering algorithm (0x01) and a simple color gradation thresholding algorithm (0x02). In the size adaptation stage, after acquiring the original image, the application calculates the scaling factor between the source image size and the physical display size fed back by the underlying hardware using a bilinear interpolation algorithm. The horizontal and vertical scaling formulas are as follows: ; ; In the scaling formula above, This represents the horizontal width scaling factor when the source image is converted to the target screen. This represents the vertical height scaling factor when the source image is converted to the target screen. The image resolution (in pixels) of the original source image is represented. This represents the actual physical pixel width that the underlying hardware window of the e-ink screen can display, obtained through NFC two-way communication. The image resolution (in pixels) of the original source image is represented. This represents the actual physical pixel height that the underlying hardware window of the e-ink screen can display, obtained through NFC two-way communication.

[0045] For aspect ratios that are not proportional, a boundary-symmetric cropping step based on image geometric center point alignment is enforced. In the specific execution of the simple color level thresholding algorithm, the application first maps the RGB space pixels of the source image point by point to a single-channel grayscale space; the grayscale conversion formula is: ; In the above grayscale conversion formula, This represents the single-channel target grayscale value obtained after weighted calculation of a single pixel. This represents the grayscale value of the red component of the pixel at that sampling point in the original red, green, and blue (RGB) color space; This represents the grayscale value of the green component of the pixel at that sampling point in the original color space; This represents the grayscale value of the blue component of the pixel at that sampling point in the original color space.

[0046] Subsequently, a logical decision threshold was established: the system takes the statistical average of the grayscale values ​​of the entire image as the dynamic cutting threshold. The specific decision condition of the algorithm is: for any pixel, if its grayscale value... If it is forced to be mapped to the hexadecimal output value 0x00 (i.e., black); if its grayscale value is... If the value is 0x01 (i.e., white), then it is mapped to 0x01. For multi-color configuration modules, the minimum Euclidean distance from a single RGB pixel to a preset standard base color (such as standard red [255,0,0]) in the three-dimensional color space is calculated, and then the corresponding color value code is strongly correlated and output.

[0047] 0x03 represents the Floyd-Steinberg algorithm, and 0x04 represents the XTDither algorithm. The algorithm converts pixels into specific hexadecimal codes: 0x00 represents black, 0x01 represents white, 0x02 or 0x03 represents a mixture of red and yellow, 0x04 represents orange, 0x05 represents green, 0x06 represents blue, and 0x07 or 0x08 represents a mixture of cyan and purple. Subsequently, the application sends the pixel matrix to the data compression module, which uses Huffman coding to compress the input data block (e.g., 2000 bytes) into a bitstream and then breaks it down into tiny data packets no larger than 250 bytes.

[0048] In the image packet transmission process, the application provides three write modes. In uncompressed mode, the application sends a sequence with a 0xF0 category and a 0xD2 instruction code, formatted as F0 D2. In the older compression mode, the instruction header is F0 D3, formatted as F0 D3, where the DecEn field controls when the decompression engine is enabled. In Huffman compression mode, the instruction header is F0 C3, formatted as F0 C3. In the Huffman protocol, the Flag field strictly defines the packet attributes: 0x00 indicates the first packet, 0x01 indicates intermediate continuous packets, and 0x02 indicates the final packet. The microcontroller reassembles the data sub-packets in memory based on the Flag bits, triggering the underlying hardware decompression engine when it detects the 0x02 flag.

[0049] During data transmission and system interaction, the system employs a security verification and retransmission mechanism. Before performing a screen refresh or write operation, the system checks the PIN code status using the command F0 D8 00 00 05 00 00 00 00 0E. A response of 9000 indicates no verification is needed; a response of 6985 requires the PIN code to be entered. The PIN verification command format is: 00 20 00 01. For example, if the PIN code is "1234", the command would be: 00 20 00 01 04 31 32 33 34. Successful verification returns a 9000 status code; an incorrect password returns a 63CX status code (X represents the remaining number of attempts); exceeding the limit returns 6983 or 6900, indicating device lock. The PIN modification command format is: 80 D9 01 02 <old PIN><new PIN>.

[0050] In the underlying fault-tolerant retransmission logic, the application strictly judges the SW1 and SW2 status words returned by each instruction. Besides the 9000 status code indicating successful execution, if it receives error codes such as 6985 (condition not met), 6A82 (file not found), 6A86 (parameter error), 6700 (length error), or 6884 (unsupported function), the application will execute an exception handling code branch. Especially in passive mode screen-flash communication, if the microcontroller is busy or not powered, it will return a 6986 (command not allowed) or 68C6 status code. In this case, the application determines that there is a transient timing overlap in the underlying link and will immediately trigger a retransmission mechanism to retry once; if it still returns 68C6, it will send a forced continuation sequence F0 D4 85 00 00 to break the deadlock state. In addition, the application layer defines a proprietary business error code system, such as: errors 1001 to 1003 for device compatibility configuration, errors 2001 to 2004 for image conversion anomalies, errors 3001 to 3005 for RF connection interruptions, error 4001 for size acquisition failure, and error 9999 for unknown anomalies; it also includes low-level parameter anomaly reports, such as screen size configuration conflict (R0), color mode anomaly (R1), scan mode error (R2), blending mode error (R3), color quantity configuration out of bounds (R4), input color value error (R5), PIN verification internal anomaly (R6), and firmware version number error (R7).

[0051] Once all image data packets have been transmitted and the underlying physical layer (e.g., CRC-A checksum) and data link layer (e.g., CRC-B checksum) have confirmed that there are no errors, such as... Figure 6 As shown, the application sends the final command to the control and drive components to perform screen refresh. When the system is in passive power mode without an independent battery, the refresh command is configured as: F0 D4 8100, where the P2 parameter is written as the image area number ranging from 0x00 to 0x7F. In active mode with auxiliary energy storage components, the P2 parameter is configured as 0x80 by setting the most significant bit (bit 7) to 1. During the subsequent charge transfer and display matrix flipping phase, the application initiates a high-frequency status polling mechanism at fixed intervals of 100ms, continuously sending the F0 DE 0000 01 command to probe the underlying progress. If the microcontroller returns 00 9000, it indicates that the refresh action is still in the execution cycle, and the application continues to maintain the output of NFC radio frequency field strength; once the microcontroller transmits the status word set 01 9000, it confirms that the physical migration of all electrophoretic particles is completely completed, and the mobile terminal can safely turn off the 13.56 MHz magnetic field excitation source, and the entire passive screen refresh electrical interaction process is declared closed.

[0052] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A power supply and refresh control system for an NFC-based e-ink screen mobile phone case, characterized in that, include: An NFC power receiving and communication component is disposed inside the phone case and close to the NFC sensing area of ​​the mobile terminal, and is used to sense the alternating magnetic field emitted by the mobile terminal to obtain alternating electrical energy and modulate image data signals. An energy management component, electrically connected to the NFC power receiving and communication component, is used to convert the AC power into DC power and store the energy to provide operating voltage to the system in stages. The control and drive component is electrically connected to the energy management component and the NFC power receiving and communication component, respectively, and is used to receive the modulated image data signal for decoding when a preset trigger condition is met, and output a pixel drive waveform according to the decoded image data. as well as An electronic ink display module is electrically connected to the control and drive components, used to refresh the display based on the pixel drive waveform, and retain the display after power-off due to the bistable characteristics of the microcapsules after the refresh is completed; The NFC power receiving and communication component enters the receiving response state only when the preset trigger condition is met, so as to avoid interference load on the native NFC high-frequency service of the mobile terminal and achieve service isolation.

2. The NFC-based e-ink screen phone case power supply and refresh control system according to claim 1, characterized in that, The energy management component includes a rectifier circuit, a voltage regulator circuit, and an energy storage unit that are connected in sequence. The rectifier circuit is used to rectify the alternating current energy generated by the alternating magnetic field into direct current energy. The voltage regulator circuit is used to step down and regulate the DC power. The energy storage unit is used to temporarily store the regulated DC power, and after the voltage reaches a set threshold, it supplies power to the control and drive components and the electronic ink display module according to a preset timing sequence.

3. The NFC-based e-ink screen phone case power supply and refresh control system according to claim 2, characterized in that, The energy storage unit uses a microcapacitor or a supercapacitor, and the energy management component also includes a low voltage detection circuit. The low-voltage detection circuit is used to monitor the charge of the microcapacitor or the supercapacitor in real time to avoid the impact of instantaneous power supply fluctuations on the refresh stability of the electronic ink display module.

4. The NFC-based e-ink screen phone case power supply and refresh control system according to claim 1, characterized in that, The control and drive components include a low-power controller and an image buffer unit; The low-power controller is used to receive the modulated image data signal packet by packet under close-range conditions, and sequentially complete frame header identification, address identification, packet reassembly, verification and confirmation, and image decoding.

5. The NFC-based e-ink screen phone case power supply and refresh control system according to claim 4, characterized in that, The control and drive components adopt segmented refresh logic, that is, after receiving and partially caching the data of one image partition in the image buffer unit, the pixel drive waveform is output to the electronic ink display module in the order of the regions to reduce the power supply pressure of a single peak.

6. The NFC-based e-ink screen phone case power supply and refresh control system according to claim 1, characterized in that, The preset triggering conditions include limiting the response to a specific instruction set or limiting the coil coupling window; By using the preset triggering conditions, the system does not respond to unauthorized high-frequency scanning signals, thus ensuring compatibility with the mobile terminal's native payment and transportation card services.

7. The NFC-based e-ink screen phone case power supply and refresh control system according to claim 1, characterized in that, The inside of the phone case body is also provided with a magnetic device installation area and a wireless charging avoidance area; The metal cover of the control and drive components adopts a metal clearance structure in the area corresponding to the wireless charging coil of the mobile terminal to reduce eddy current losses generated by the high-frequency magnetic field, thereby maintaining the normal operation of the wireless charging and magnetic alignment functions of the mobile terminal.

8. The NFC-based e-ink screen phone case power supply and refresh control system according to claim 1, characterized in that, The electronic ink display module has a transparent protective layer stacked on its outer side, and the mobile phone case body also includes an outer shielding PET layer and an inner magnetic PET layer. The transparent protective layer remains fully transparent in the corresponding display window area, and in the non-display area, it combines with the shielding PET layer to cover the internal components.

9. The NFC-based e-ink screen phone case power supply and refresh control system according to claim 1, characterized in that, The modulated image data signal is generated and modulated by an application terminal set within the mobile terminal; The application performs size adaptation and color mode mapping on the content to be displayed, and packages the content into a data packet suitable for NFC bandwidth and power limitations through an image compression algorithm.

10. The NFC-based e-ink screen phone case power supply and refresh control system according to claim 1, characterized in that, After the screen refresh is complete, the energy management component of the electronic ink display module stops outputting power to the control and drive component, and the system enters a zero standby power consumption state.

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