Shielded enhanced smart card substrate

Abstract

The utility model discloses a shielding reinforced type intelligent card substrate, include: multilayer composite substrate is from top to bottom in proper order surface protection layer, shielding reinforced layer, core substrate layer, chip module integrated layer and bottom layer protection film, shielding reinforced layer is composed of conductive grid layer and wave absorbing material layer, conductive grid layer adopts nanometer silver line or copper foil formation faraday cage structure, and wave absorbing material layer is ferrite or carbon base composite material, dynamic shielding subassembly, including: miniature electromagnetic sensor array, is embedded between shielding reinforced layer and core substrate layer, tunable shielding layer is composed of conductive polymer or ferromagnetic composite material, control unit is integrated in the core substrate layer, the utility model discloses bimodulus shielding layer makes shielding effectiveness to promote to >=30db, and dynamic detection interference information is responded to the interference of multiband.

Description

Technical Field

[0001] This utility model relates to the field of smart card structure technology, specifically to a shielded enhanced smart card substrate. Background Technology

[0002] With the rapid development of wireless communication technology, smart cards, as an important information security carrier, have been widely used in finance, transportation, identity authentication and other fields. The smart card substrate, as a core component of the smart card, undertakes functions such as electrical interconnection between the chip and the external environment, protection, support, heat dissipation, and assembly. Its performance directly affects the security and reliability of the smart card.

[0003] In the context of increasingly complex wireless communication environments, smart cards face the challenge of multi-band interference. This interference can originate from surrounding wireless devices, electromagnetic radiation sources, etc., causing malfunctions in the internal circuitry of the smart card, and even leading to serious problems such as data loss or incorrect transmission. Especially in critical scenarios such as financial transactions and identity authentication, the security of smart cards is paramount, and even the slightest interference can result in incalculable losses.

[0004] Traditional smart card substrates have significant shortcomings in dealing with multi-frequency interference. On the one hand, the substrate's shielding performance is limited, making it difficult to effectively block electromagnetic interference from different frequency bands; on the other hand, the substrate's anti-interference mechanism lacks flexibility and cannot intelligently adjust according to the characteristics of interference from different frequency bands. These limitations severely restrict the adaptability and reliability of smart cards in different environments. Summary of the Invention

[0005] In order to overcome the shortcomings of existing technical solutions, this utility model provides a shielded enhanced smart card substrate, which can effectively solve the problem that static shielding cannot cope with multi-band interference as mentioned in the background technology.

[0006] The technical solution adopted by this utility model to solve its technical problem is: a shielded enhanced smart card substrate, comprising: The multilayer composite substrate consists of, from top to bottom, a surface protective layer, a shielding enhancement layer, a core substrate layer, a chip module integration layer, and a bottom protective film. The shielding enhancement layer is composed of a conductive mesh layer and a microwave absorbing material layer. The conductive mesh layer is formed into a Faraday cage structure using silver nanowires or copper foil, and the microwave absorbing material layer is a ferrite or carbon-based composite material. Dynamic shielding components, including: A miniature electromagnetic sensor array, embedded between the shielding enhancement layer and the core substrate layer, is used to detect the intensity and spectral characteristics of electromagnetic signals in the 1MHz-5GHz frequency band. The tunable shielding layer is made of conductive polymer or ferromagnetic composite material, and its impedance characteristics can be adjusted by an external electric field or current. The control unit, integrated within the core substrate layer, receives sensor signals and outputs control commands for the shielding layer.

[0007] Furthermore, the conductive polymer of the tunable shielding layer is PEDOT or polypyrrole.

[0008] Furthermore, the micro electromagnetic sensor array includes at least three sensor nodes, covering the four corners and the central area of ​​the substrate.

[0009] Furthermore, the surface protective layer is made of PET material and coated with an antistatic coating.

[0010] Furthermore, a temperature sensor is provided between the shielding enhancement layer and the core substrate layer. When the temperature is detected to be ≥80℃, the control unit is triggered to shut down the chip communication interface.

[0011] Compared with the prior art, the beneficial effects of this utility model are: A miniature electromagnetic sensor array can monitor changes in the electromagnetic environment in real time and rapidly adjust the impedance characteristics of a tunable shielding layer via a control unit, thereby achieving real-time response and regulation to electromagnetic interference. This dynamic shielding mechanism helps reduce the impact of electromagnetic interference on the internal circuitry and chip of the smart card, improving its stability and security. The tunable shielding layer can be adjusted according to different electromagnetic interference environments and frequency ranges, making the smart card suitable for a wider range of electromagnetic environments. This adaptability helps the smart card maintain stable performance in various complex environments. Attached Figure Description

[0012] Figure 1 This is an exploded view of the structure of this utility model; Figure 2 This is a schematic diagram of the structure of this utility model; Figure 3 This is a schematic diagram of the distribution of the miniature electromagnetic sensor array structure of this utility model; Figure 4 This is a schematic diagram of the shielding reinforcement layer structure of this utility model; Figure 5 This is a schematic diagram of the antistatic coating structure of this utility model.

[0013] Numbering on the map: 1-Surface protective layer, 2-Shielding enhancement layer, 3-Core substrate layer, 4-Chip module integration layer, 5-Bottom protective film, 6-Temperature sensor, 7-Dynamic shielding component, 8-Antistatic coating, 21-Conductive mesh layer, 22-Wave absorption material layer, 71-Miniature electromagnetic sensor array, 72-Tunable shielding layer, 73-Control unit. Detailed Implementation

[0014] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0015] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0016] like Figure 1-5 As shown, this utility model provides a shielded enhanced smart card substrate, comprising: The multilayer composite substrate consists of, from top to bottom, a surface protective layer 1, a shielding enhancement layer 2, a core substrate layer 3, a chip module integration layer 4, and a bottom protective film 5. The shielding enhancement layer 2 and the core substrate layer 3 are bonded using a hot-press bonding process with parameters set at 180℃, 5MPa, and 30 seconds to ensure an interlayer bonding strength ≥20MPa. The shielding enhancement layer 2 is composed of a conductive mesh layer 21 and an absorbing material layer 22. The conductive mesh layer 21 is formed into a Faraday cage structure using silver nanowires or copper foil, and the absorbing material layer 22 is made of ferrite or carbon-based composite material. The conductive mesh layer 21 is located above the absorbing material layer 22, and the two are isolated by a 0.5μm polyimide insulating layer to form a reflection-absorption synergistic structure. The conductive mesh layer 21 and the chip antenna area are designed with a cutout, with a minimum spacing ≥1mm, to avoid near-field coupling interference. Dynamic shielding component 7 includes: The miniature electromagnetic sensor array 71 is embedded between the shielding enhancement layer 2 and the core substrate layer 3. It is used to detect the electromagnetic signal strength and spectral characteristics in the 1MHz-5GHz frequency band. The sensor array is fabricated on a polyimide substrate by photolithography and the detection coil is formed by inkjet printing silver paste. The final package thickness is ≤50μm. The tunable shielding layer 72 is made of conductive polymer or ferromagnetic composite material, and its impedance characteristics are adjusted by an external electric field or current. The control unit 73 is integrated in the core substrate layer 3. It receives sensor signals and outputs shielding layer control commands. The control unit 73 uses a pre-trained convolutional neural network to classify spectral features and identify the type of interference source.

[0017] The conductive mesh layer 21 adopts a Faraday cage structure formed by silver nanowires or copper foil, which can effectively guide and disperse electromagnetic waves and prevent them from penetrating the substrate, thereby protecting the internal chip module from electromagnetic interference.

[0018] The absorbing material layer 22 is composed of ferrite or carbon-based composite material. The thickness of the ferrite layer is preferably 20-50 μm, and the dielectric loss tangent of the carbon-based composite material is ≥0.8. This can absorb and consume the incident electromagnetic wave energy, further reduce the reflection and propagation of electromagnetic waves, and improve the electromagnetic shielding effect.

[0019] The tunable shielding layer 72 is made of conductive polymer or ferromagnetic composite material, and its impedance characteristics can be adjusted by an external electric field or current. This allows for optimization of the shielding effect by adjusting the characteristics of the shielding layer, thereby ensuring the stability and security of the smart card at different frequency bands.

[0020] A miniature electromagnetic sensor array 71 is embedded between the shielding enhancement layer 2 and the core substrate layer 3, capable of detecting the intensity and spectral characteristics of electromagnetic signals in the 1MHz~5GHz frequency band. This enables the smart card to monitor the surrounding electromagnetic environment in real time, providing data support for subsequent shielding layer adjustments.

[0021] The control unit 73 is integrated within the core substrate layer 3 and is responsible for receiving sensor signals and outputting shielding layer control commands. Through intelligent algorithms and logical judgments, the control unit 73 can dynamically adjust the characteristics of the tunable shielding layer 72 according to the electromagnetic signal strength and spectral characteristics detected by the sensor to achieve the best electromagnetic shielding effect.

[0022] To prevent electromagnetic interference, the shielded enhanced smart card substrate can effectively prevent external electromagnetic interference from affecting the internal chip module through the electromagnetic shielding and protection mechanisms described above, thereby improving the stability and reliability of the smart card.

[0023] Electromagnetic waves are initially shielded by a conductive mesh layer 21, and residual waves are dissipated by an absorbing material layer 22. The micro-sensor array uses a superheterodyne receiver architecture to detect signal strength in the 1MHz-5GHz range and performs FFT transformation to generate spectral feature vectors. Sensor data is transmitted to the control unit 73 via an SPI bus, and a pre-trained MobileNetV3 lightweight CNN model is used to classify the spectrum. If the peak frequency is between 13.56MHz and 920MHz and the bandwidth is less than 2MHz, it is considered RFID reader interference. If the frequency transition period is less than 10ms and the center frequency is 2.4GHz, it is determined to be Bluetooth / WiFi interference; Otherwise, it will be judged as a malicious electromagnetic attack.

[0024] The conductive polymer of the tunable shielding layer 72 is PEDOT or polypyrrole, with a surface resistivity ranging from 10 Ω·cm at 0-5V. 6 The Ω / sq is reduced to 10⁻²Ω / sq, enabling high-frequency electromagnetic wave reflection.

[0025] The PEDOT layer surface is covered with a 10nm silicon nitride passivation layer, and after aging at 85℃ / 85%RH for 1000 hours, the resistivity drift is <5%.

[0026] PEDOT and polypyrrole, as conductive polymers, possess excellent conductivity and tunable electromagnetic parameters. Their surface resistivity changes significantly within a voltage range of 0–5V, enabling dynamic control of electromagnetic wave reflection characteristics. When a voltage of 0–5V is applied, PEDOT:SULF can rapidly switch between a metallic state and an insulating state. In the metallic state, PEDOT:SULF exhibits a surface effect similar to a perfect conductor, and its metallic plasma properties significantly influence the surrounding electromagnetic field distribution. In the insulating state, PEDOT:SULF exhibits dielectric properties, and its losses weaken the radiation modes of dipoles within the surrounding structure. When the surface resistivity decreases to 10⁻²Ω / sq, these conductive polymers can form a highly efficient electromagnetic wave reflecting layer, effectively reflecting incident electromagnetic waves back and reducing electromagnetic wave penetration and energy loss.

[0027] By adjusting the external electric field or current, the impedance characteristics of PEDOT or polypyrrole conductive polymers can be adjusted in real time, thereby achieving dynamic control over the shielding effect of the shielding layer. This dynamic shielding effect allows the smart card to adapt to different electromagnetic environments and provide additional electromagnetic protection when needed. For example, in environments with strong electromagnetic interference, the surface resistivity can be reduced by increasing the voltage to improve the reflection effect; while in relatively weak electromagnetic environments, the voltage can be reduced to lower energy consumption.

[0028] See Figure 3 The miniature electromagnetic sensor array 71 contains at least three sensor nodes, is integrated using MEMS technology, has a thickness of ≤50μm, covers the four corners and the central area of ​​the substrate, and converts the detection signal into frequency domain features using an FFT algorithm.

[0029] Multiple sensor nodes in the array can simultaneously monitor electromagnetic signals at different locations, thus providing more comprehensive and accurate electromagnetic environment monitoring data. By using the FFT algorithm to convert the detected signals in the time domain into frequency domain features, electromagnetic signals of different frequencies can be identified and analyzed more clearly, improving monitoring accuracy.

[0030] Based on the electromagnetic signal strength and spectral characteristics monitored by the sensor array, the characteristics of the tunable shielding layer 72 can be dynamically adjusted to achieve a more precise electromagnetic shielding effect. The sensor array can monitor changes in the electromagnetic environment in real time and quickly feed back to the control unit 73, thereby enabling real-time adjustment of the shielding layer characteristics and ensuring the stability and security of the smart card under different electromagnetic environments.

[0031] See Figure 5 The surface protective layer 1 is made of PET material, coated with an antistatic coating 8, with a resistivity ≤10. 6 Ω / sq, the bottom protective film 5 is made of halogen-free flame retardant material.

[0032] PET is a thermoplastic polyester with excellent physical and mechanical properties, electrical insulation properties and chemical resistance. It has high transparency, good gloss, and is easy to process and mold, making it suitable as a surface protective layer for smart card substrates.

[0033] Applying an antistatic coating 8 to the PET surface can significantly reduce the surface resistivity to ≤10. 6 Ω / sq, the antistatic coating 8 can prevent static electricity buildup and discharge, protecting the internal circuits and chips from static interference and damage. In addition, the antistatic coating 8 can also reduce the adhesion of dust and dirt, keeping the surface of the smart card clean and beautiful.

[0034] The bottom protective film 5 is made of halogen-free flame-retardant material, which means that it will not release harmful gases such as hydrogen halides during combustion, meeting environmental protection requirements. This material has excellent flame-retardant properties and can maintain structural stability at high temperatures to prevent the spread of fire.

[0035] See Figure 1 A temperature sensor 6 is installed between the shielding enhancement layer 2 and the core substrate layer 3. When the temperature is detected to be ≥80℃, the control unit 73 is triggered to shut down the chip communication interface.

[0036] When a smart card is in a high-temperature environment, its internal chip may be damaged due to overheating. By setting a temperature sensor 6 and a temperature threshold of 80°C, when the temperature reaches or exceeds this threshold, the control unit 73 will quickly shut down the chip's communication interface, thereby cutting off the chip's communication with the external environment, preventing the chip from being further damaged by heat, and extending its service life.

[0037] High temperatures can cause data loss or corruption within smart cards. By promptly shutting down the chip's communication interface, data can be prevented from being erroneously read, written, or modified under high-temperature conditions, thus ensuring data integrity and security.

[0038] Example 1: Financial Payment Card Application Structural configuration: Core substrate layer 3: FR4 epoxy resin substrate (0.5mm thick), with copper-plated circuit impedance matched to 50Ω.

[0039] Shielding reinforcement layer 2: Conductive mesh layer 21: Silver nanowire mesh (line width 0.08 mm, spacing 0.1 mm, coverage 98%). Wave-absorbing material layer 22: Ferrite powder-filled polyurethane composite material (thickness 30μm, μ'=55@1GHz).

[0040] Dynamic shielding component 7: Sensor nodes: 5 MEMS sensors (four corners + center layout, detection accuracy ±0.5dBm).

[0041] Tunable shielding layer 72: PEDOT conductive layer (surface resistivity 0.1-10) 6 Ω / sq adjustable).

[0042] Test data: Example 2: Application of ID Cards Surface protective layer 1: Antistatic PET (surface resistivity 10) 5 Ω / sq), superimposed with anti-counterfeiting holographic patterns.

[0043] Chip module integration layer 4: The dual-band antenna (13.56MHz / 920MHz) adopts a fractal structure layout (Hilbert curve).

[0044] A ring-shaped shielding groove (0.2mm wide, 0.1mm deep) is provided in the chip area.

[0045] Dynamic masking algorithm: The CNN model training dataset includes RFID / NFC / WiFi interference spectral features (sample size > 10). 4 Group.

[0046] Response time ≤ 35ms (2.4GHz frequency hopping interference scenario).

[0047] Test results: Humid heat aging: After 1000 hours at 85℃ / 85%RH, the shielding effectiveness decreases by <0.5dB.

[0048] Mechanical bending: After 1000 bends with a radius of 35mm, the breakage rate of the conductive mesh is <0.01%.

[0049] Example 3: Industrial Control Card (Adapted for Extreme Environments) Substrate material: Polyimide substrate (thickness 0.3mm, Tg>250℃).

[0050] Tunable shielding layer 72: The operating voltage range is extended to -3V to +8V (suitable for strong electromagnetic interference scenarios).

[0051] Impedance adjustment accuracy ±5% (0-1GHz band).

[0052] Temperature compensation: Integrated thin-film thermocouple (sensitivity 60μV / ℃) dynamically adjusts the dielectric constant of the absorbing material.

[0053] EMC test results: Comparative Example (Conventional Technology): In the description of this utility model, it should be understood that the terms "middle", "length", "upper", "lower", "front", "rear", "vertical", "horizontal", "inner", "outer", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0054] In this invention, unless otherwise expressly specified and limited, the first feature "on" the second feature may be in direct contact with the first feature, or indirect contact with the first feature through an intermediate medium. "A plurality of" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0055] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0056] The above description is merely illustrative of the embodiments of this utility model and is not intended to limit the scope of this utility model. For those skilled in the art, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model without creative labor should be included within the protection scope of this utility model.

Claims

1. A shielded enhanced smart card substrate, characterized in that, include: The multilayer composite substrate consists of, from top to bottom, a surface protective layer, a shielding enhancement layer, a core substrate layer, a chip module integration layer, and a bottom protective film. The shielding enhancement layer is composed of a conductive mesh layer and a microwave absorbing material layer. The conductive mesh layer is formed into a Faraday cage structure using silver nanowires or copper foil, and the microwave absorbing material layer is a ferrite or carbon-based composite material. Dynamic shielding components, including: A miniature electromagnetic sensor array, embedded between the shielding enhancement layer and the core substrate layer, is used to detect the intensity and spectral characteristics of electromagnetic signals in the 1MHz-5GHz frequency band. The tunable shielding layer is made of conductive polymer or ferromagnetic composite material, and its impedance characteristics can be adjusted by an external electric field or current. The control unit, integrated within the core substrate layer, receives sensor signals and outputs control commands for the shielding layer.

2. The shielded enhanced smart card substrate according to claim 1, characterized in that: The conductive polymer of the tunable shielding layer is PEDOT or polypyrrole.

3. The shielded enhanced smart card substrate according to claim 1, characterized in that: The micro electromagnetic sensor array contains at least three sensor nodes, covering the four corners and the central area of ​​the substrate.

4. The shielded enhanced smart card substrate according to claim 1, characterized in that: The surface protective layer is made of PET material and coated with an antistatic coating.

5. The shielded enhanced smart card substrate according to claim 1, characterized in that: A temperature sensor is installed between the shielding enhancement layer and the core substrate layer. When the temperature is detected to be ≥80℃, the control unit is triggered to shut down the chip communication interface.

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