License plate

Abstract

The license plate is used for transmitting license plate information to a license plate recognition device and comprises a substrate, a pressure-sensitive adhesive layer and a reflective film which are arranged in a stacked mode, and a chip is arranged in the pressure-sensitive adhesive layer. Wherein the reflective film is adhered to the substrate through the pressure-sensitive adhesive layer and can be penetrated by signal waves of a license plate recognition device, and license plate information is stored in the chip. The chip communicates with the license plate recognition device through signal waves. When the license plate recognition device emits signal waves, the signal waves can penetrate through the reflective film to interact with the chip arranged between the reflective film without signal shielding and the substrate. And after the chip receives the signal wave, the stored license plate information is coded and modulated on the returned signal wave, and finally is fed back to the license plate recognition device.

Description

Technical Field

[0001] This utility model relates to a license plate, and more particularly to a license plate that can be recognized by millimeter waves. Background Technology

[0002] Currently, license plate recognition primarily relies on high-definition cameras continuously capturing images of license plates, which are then identified using computer vision and image processing technologies. This method is widely used in traffic monitoring, automated toll collection, and parking management. However, under certain circumstances, the license plate images captured by the cameras may be affected by external factors, leading to incorrect license plate recognition. For example, dirt, glare, or human obstruction of the license plate surface can degrade the image quality, thus affecting the accuracy and stability of the recognition system.

[0003] To address this issue, related technologies embed RFID tags on license plates and combine them with RFID readers in license plate recognition devices. This allows the system to directly read license plate information without relying on camera capture. While this method overcomes the environmental limitations of image recognition, the accuracy of RFID may decrease at high speeds, especially over long distances, where signal attenuation and reflection can lead to recognition failures. Furthermore, RFID technology relies on additional hardware, such as onboard tags and readers, increasing the system's complexity. Utility Model Content

[0004] In view of this, the purpose of this utility model is to provide a license plate that can transmit license plate information stably and accurately even in complex environments.

[0005] This utility model provides a license plate for transmitting license plate information to a license plate recognition device, comprising a substrate, a pressure-sensitive adhesive layer and a reflective film stacked together, wherein a chip is disposed inside the pressure-sensitive adhesive layer.

[0006] In one embodiment, the reflective film includes a face film layer, a bead layer, a focal layer, and a reflective layer arranged sequentially, with the reflective layer on the side closer to the pressure-sensitive adhesive layer and the face film layer on the side farther from the pressure-sensitive adhesive layer.

[0007] In one embodiment, the reflective film further includes a printing layer, which is attached to the surface of the mask layer by an adhesive layer.

[0008] In one embodiment, the thickness of the printed layer is 50μm-200μm, the bonding layer is a UV adhesive, the transmittance of the bonding layer is greater than 90%, and the thickness is 5μm-20μm.

[0009] In one embodiment, the reflective layer is an indium tin alloy.

[0010] In one embodiment, the reflective layer is a dielectric material, comprising at least one first dielectric layer and at least one second dielectric layer, wherein the first dielectric layer and the second dielectric layer are alternately stacked, and the refractive index of the first dielectric layer is 0.05 to 2 greater than the refractive index of the second dielectric layer;

[0011] The first dielectric layer is a zinc sulfide dielectric layer or a titanium dioxide dielectric layer, and the second dielectric layer is a magnesium fluoride dielectric layer or a PMMA dielectric layer.

[0012] In one embodiment, the mask layer is an acrylic adhesive layer with a thickness of 20μm-40μm.

[0013] In one embodiment, the bead layer is semi-embedded glass microspheres in acrylic adhesive, the bead layer thickness is 20μm-80μm, the glass microspheres are 200 mesh-500 mesh, and the refractive index of the glass microspheres is 1.9 or 2.2.

[0014] This invention provides a license plate in which a chip is placed between a reflective film without signal shielding and a substrate, enabling the license plate to communicate effectively with a license plate recognition device via signal waves. Even in complex environments such as low visibility, dirt, reflection, or obstruction, it can still stably and accurately transmit license plate information. Furthermore, this license plate does not rely on additional hardware support and has high recognition accuracy, stability, and anti-interference capabilities. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a license plate provided in the first embodiment of the present utility model.

[0017] Figure 2 This is a schematic diagram of the structure of the reflective layer provided in the second embodiment of the present invention.

[0018] Figure label:

[0019] 1. Reflective film; 2. Pressure-sensitive adhesive layer; 3. Chip; 4. Substrate; 11. Printing layer; 12. Adhesive layer; 13. Face film layer; 14. Bead layer; 15. Focal point layer; 16. Reflective layer; 21. First adhesive layer; 22. Second adhesive layer; 23. Support layer; 24. Third adhesive layer; 161. First dielectric layer; 162. Second dielectric layer. Detailed Implementation

[0020] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of this utility model. Based on the description of this utility model, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this utility model.

[0021] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0022] The terms “upper,” “lower,” “left,” “right,” “front,” “back,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of description and simplification, 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.

[0023] The terms “first,” “second,” “third,” etc., are used merely to distinguish elements with similar properties, not to indicate or imply relative importance or a specific order.

[0024] The terms “include,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0025] First Embodiment

[0026] Please refer to Figure 1The first embodiment of this utility model provides a license plate for transmitting license plate information to a license plate recognition device. The license plate includes a substrate 4, a pressure-sensitive adhesive layer 2, and a reflective film 1 stacked together. The reflective film 1 is permeable by signal waves emitted by the license plate recognition device and is bonded to the substrate 4 via the pressure-sensitive adhesive layer 2. A chip 3 is disposed inside the pressure-sensitive adhesive layer 2, storing the license plate information. The chip 3 communicates with the license plate recognition device via signal waves. When the license plate recognition device emits a signal wave, the signal wave can pass through the reflective film 1 and interact with the chip 3 encased in the pressure-sensitive adhesive layer 2. After receiving the signal wave, the chip 3 encodes the stored license plate information and modulates it onto the returned signal wave, ultimately feeding it back to the license plate recognition device. Through this configuration, the license plate can maintain good data transmission performance in various complex environments, such as when the license plate surface is contaminated, reflective, or partially obscured, it can still effectively transmit the license plate information to the license plate recognition device.

[0027] In this embodiment, the reflective film 1 includes a face film layer 13, a beaded layer 14, a focal layer 15, and a reflective layer 16 arranged sequentially. The reflective layer 16 is located closer to the pressure-sensitive adhesive layer 2, while the face film layer 13 is located away from the pressure-sensitive adhesive layer 2. The face film layer 13 is made of acrylic acid with a thickness of 20μm-40μm, possessing good flexibility and transparency, effectively protecting the beaded layer 14. The reflective layer 16 primarily reflects light illuminating the license plate, while the focal layer 15 adjusts the propagation path of the reflected light, making it more focused and ensuring high visibility of the license plate under low-light conditions.

[0028] Preferably, the reflective film 1 further includes a printed layer 11, which is adhered to the surface of the film layer 13 via an adhesive layer 12. The printed layer 11 is made of aging-resistant PVC material with a thickness of 50μm-200μm. License plate identification information, such as vehicle number and related patterns, is printed on the surface of the printed layer 11. The aging-resistant PVC material has excellent UV resistance and weather resistance, effectively resisting aging phenomena caused by long-term exposure to harsh environments such as sunlight, rain, and high temperatures, thereby extending the service life of the license plate. Specifically, the adhesive layer 12 is a UV adhesive with a thickness of 5μm-20μm and a transmittance greater than 90%, effectively ensuring the transmission of light and signal waves and avoiding affecting the performance of other functional layers within the reflective film 1.

[0029] In this embodiment, the signal wave is a millimeter wave, which has the characteristics of short wavelength and strong penetration ability. It can pass through the reflective film 1 and interact with the chip 3 embedded therein. The reflective layer 16 in the reflective film 1 is made of indium tin alloy, which has a high reflectivity, effectively enhancing the reflective performance of the license plate and improving its visibility in low-light or complex environments. At the same time, indium tin alloy has excellent millimeter wave penetration performance, ensuring that the reflective film 1 has high reflectivity without affecting the propagation of millimeter waves, thereby ensuring the stability and accuracy of communication between the chip 3 and the millimeter wave recognition device.

[0030] Furthermore, the pressure-sensitive adhesive layer 2 includes a first adhesive layer 21, a second adhesive layer 22, a support layer 23, and a third adhesive layer 24 arranged sequentially from the outside to the inside. The chip 3 is disposed between the first adhesive layer 21 and the second adhesive layer 22, and the chip 3 is surrounded by the first adhesive layer 21 and the second adhesive layer 22. The support layer 23 is located below the second adhesive layer 22 and is bonded to the substrate 4 through the third adhesive layer 24. The support layer 23 is a PVC film layer, which is mainly used to enhance the overall strength and stability of the pressure-sensitive adhesive layer 2 and prevent the pressure-sensitive adhesive layer 2 from separating from the substrate 4 or the reflective film 1.

[0031] Specifically, the first adhesive layer 21, the second adhesive layer 22, and the third adhesive layer 24 are all made of acrylic pressure-sensitive adhesive with a thickness of 30μm-80μm. Acrylic pressure-sensitive adhesive not only has excellent bonding properties but also maintains stable adhesion under different temperature and humidity conditions, thereby improving the environmental adaptability of the license plate. Furthermore, acrylic pressure-sensitive adhesive has good flexibility and cushioning properties, effectively absorbing external pressure or vibration, protecting the chip 3 embedded between the pressure-sensitive adhesive layers 2, and preventing damage to the chip 3 due to stress concentration.

[0032] Preferably, the bead layer 14 is made of semi-embedded glass microspheres in acrylic adhesive. The thickness of the bead layer 14 is 20μm-80μm, the glass microspheres are 200 mesh-500 mesh, and the refractive index of the glass microspheres is 1.9 or 2.2, so that they can be stably fixed. At the same time, the exposed part of the glass microspheres can effectively reflect light under illumination, enhancing the visibility and recognition effect of the license plate.

[0033] Second Embodiment

[0034] Please refer to Figure 2 The difference between the license plate provided in the second embodiment of this utility model and the first embodiment is that, in this embodiment, the reflective layer 16 includes at least one first dielectric layer 161 and at least one second dielectric layer 162, the first dielectric layer 161 and the second dielectric layer 162 are alternately stacked, and the refractive index of the first dielectric layer 161 is 0.05~2 greater than the refractive index of the second dielectric layer 162.

[0035] Specifically, the first dielectric layer 161 is a zinc sulfide dielectric layer or a titanium dioxide dielectric layer, which have high refractive indices. The second dielectric layer 162 is a magnesium fluoride dielectric layer or a PMMA dielectric layer, which have low refractive indices. The two layers produce a high refractive index difference, thus resulting in excellent reflective properties.

[0036] First comparison

[0037] The difference between the license plate provided in the first embodiment of the present invention and the first embodiment described above is that, in this embodiment, the reflective layer 16 is made of aluminum.

[0038] The reflective films prepared in the first embodiment, the second embodiment, and the first comparative example were laminated onto the surface of an aluminum plate and stamped. The retroreflection coefficient of the license plate and the signal strength of the chip were tested. The test results are shown in Table 1.

[0039]

[0040] Table 1. Test results of the reflective films prepared in the first embodiment, the second embodiment, and the first comparative example.

[0041] In summary, this utility model uses an indium tin alloy and a high-low-high dielectric structure (i.e., first dielectric layer 161-second dielectric layer 162-first dielectric layer 161) to fabricate the reflective film 1, which not only ensures the high retroreflective performance of the license plate and enhances the visibility of the license plate, but also ensures the high transmittance of millimeter waves and the strong communication capability between the chip 3 and the license plate recognition device.

[0042] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0043] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the appended claims.

Claims

1. A license plate for transmitting license plate information to a license plate recognition device, characterized in that, The device includes a substrate (4), a pressure-sensitive adhesive layer (2), and a reflective film (1) stacked together. A chip (3) is disposed inside the pressure-sensitive adhesive layer (2). The pressure-sensitive adhesive layer (2) includes a first adhesive layer (21), a second adhesive layer (22), a support layer (23), and a third adhesive layer (24) arranged sequentially from the outside to the inside. The chip (3) is disposed between the first adhesive layer (21) and the second adhesive layer (22). The chip (3) is surrounded by the first adhesive layer (21) and the second adhesive layer (22). The support layer (23) is located below the second adhesive layer (22) and is bonded to the substrate (4) through the third adhesive layer (24).

2. The license plate as described in claim 1, characterized in that, The reflective film (1) includes a face film layer (13), a bead layer (14), a focal layer (15), and a reflective layer (16) arranged in sequence. The reflective layer (16) is located on the side close to the pressure-sensitive adhesive layer (2), and the face film layer (13) is located on the side away from the pressure-sensitive adhesive layer (2).

3. The license plate as described in claim 2, characterized in that, The reflective film (1) also includes a printing layer (11), which is attached to the surface of the mask layer (13) by an adhesive layer (12).

4. The license plate as described in claim 3, characterized in that, The thickness of the printed layer (11) is 50μm-200μm, and the bonding layer (12) is a UV adhesive with a transmittance greater than 90% and a thickness of 5μm-20μm.

5. The license plate as described in claim 2, characterized in that, The reflective layer (16) is an indium tin alloy.

6. The license plate as described in claim 2, characterized in that, The reflective layer (16) is a dielectric material, including at least one first dielectric layer (161) and at least one second dielectric layer (162). The first dielectric layer (161) and the second dielectric layer (162) are alternately stacked. The refractive index of the first dielectric layer (161) is 0.05~2 greater than that of the second dielectric layer (162). The first dielectric layer (161) is a zinc sulfide dielectric layer or a titanium dioxide dielectric layer, and the second dielectric layer (162) is a magnesium fluoride dielectric layer or a PMMA dielectric layer.

7. The license plate as described in claim 2, characterized in that, The mask layer (13) is an acrylic adhesive layer with a thickness of 20μm-40μm.

8. The license plate as described in claim 2, characterized in that, The bead layer (14) is made of semi-embedded glass microspheres in acrylic glue. The thickness of the bead layer (14) is 20μm-80μm, the glass microspheres are 200 mesh-500 mesh, and the refractive index of the glass microspheres is 1.9 or 2.2.

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