A hot stamping film coding anti-counterfeiting method based on frequency selective surface

Abstract

The present invention provides a method for anti-counterfeiting of hot stamping film coding based on frequency selective surface, comprising: arbitrarily selecting 10 frequencies; designing a resonant unit set corresponding to the frequency; designing a string of N-bit anti-counterfeiting codes; selecting an anti-counterfeiting area on the cold stamping film, determining the frequency corresponding to the unit anti-counterfeiting block; preparing a corresponding resonant unit set in each unit anti-counterfeiting block area on the cold stamping film; and then transferring the cold stamping film to the product surface. During anti-counterfeiting detection, the gating frequency of each unit anti-counterfeiting block is detected, and the gating frequency is compared to see whether it is the same as the frequency corresponding to the unit anti-counterfeiting block; if all are the same, it means that the product is authentic, otherwise, the product is fake. The present invention utilizes the advantage of good frequency selectivity of the frequency selective surface, designs a frequency selective surface structure corresponding to the frequency, and prepares a surface structure corresponding to the corresponding code on the cold stamping film based on the coding combination, so as to realize advanced anti-counterfeiting function, and has the advantages of high anti-counterfeiting, good adaptability, low cost, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-counterfeiting films, and in particular relates to a hot stamping film coding anti-counterfeiting method based on frequency selective surface. Background Art

[0002] The current anti-counterfeiting technologies mainly include laser holographic labels, hidden image anti-counterfeiting, barcodes, QR codes, chemical ink printing, etc. These anti-counterfeiting methods are widely used because their physical principles are simple and easy to understand, they can be industrialized and have low production costs. However, with the popularization and publicity of these technologies, their anti-counterfeiting functions have been significantly reduced, which is not conducive to achieving high-level anti-counterfeiting. Therefore, there is an urgent need to seek an anti-counterfeiting technology with a higher production technology threshold and safety and reliability.

[0003] The Chinese invention patent application with application number 202210334315.4 discloses a near-field and far-field dual-channel image display method based on metasurface materials. This method combines the metasurface microstructure with the QR code pattern method to realize image display to achieve anti-counterfeiting. The Chinese invention patent application with application number 202210478851.1 discloses a face recognition method based on the anti-counterfeiting authentication scene of the returned photo verification. This method realizes anti-counterfeiting by making special anti-counterfeiting textures or anti-counterfeiting patterns, taking photos for analysis and uploading them during query, and performing online comparison. These schemes are easy to forge at low cost and in large quantities through high-precision copying and other methods, which reduces the security and reliability of the anti-counterfeiting code, and often requires the information of the anti-counterfeiting texture or pattern to be stored in the server in advance, which requires a large amount of storage space and is relatively time-consuming to verify.

[0004] In addition, a typical photochromic anti-counterfeiting film (CN114685832A) usually includes a base layer, a visible and hidden layer, and a surface covering layer. Different colors are achieved by adjusting the ratio of fluorescent dyes in the visible and hidden layers. Visually, it appears as one color transforming into another. The effect is relatively simple, the reliability is not high, and it cannot meet higher-level anti-counterfeiting requirements. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a hot stamping film coding anti-counterfeiting method based on a frequency selective surface.

[0006] The present invention is achieved through the following technical solutions:

[0007] A hot stamping film coding anti-counterfeiting method based on a frequency selective surface comprises the following steps:

[0008] (1) In the frequency range of 100kHz~1MHz, randomly select 10 frequencies and encode them from small to large as 0-9;

[0009] (2) designing a resonant unit set corresponding to each frequency selected in step (1), the resonant unit set comprising a plurality of resonant units of the same shape and arranged periodically;

[0010] (3) Design an anti-counterfeiting code, which is N digits from 0 to 9, where N ≥ 1;

[0011] (4) Select an area on the cold foil film as the anti-counterfeiting area, divide the anti-counterfeiting area into N unit anti-counterfeiting blocks, and sort the N unit anti-counterfeiting blocks in order of 1 to N, requiring each unit anti-counterfeiting block to correspond to a unique digit; and correspond each unit anti-counterfeiting block to each digit of the anti-counterfeiting code described in step (3) digit by digit in the order of 1 to N;

[0012] (5) According to the number corresponding to each unit anti-counterfeiting block in the anti-counterfeiting area and the corresponding relationship between the number and the frequency in step (1), the frequency corresponding to each unit anti-counterfeiting block is determined; according to the characteristics of the resonant unit set corresponding to the frequency designed in step (2), a corresponding resonant unit set is prepared in each unit anti-counterfeiting block area on the cold stamping film;

[0013] (6) Transfer the cold stamping film with the anti-counterfeiting area to the surface of the product. The substrate of the product must not be metal and the thickness must not exceed 10 mm;

[0014] (7) During anti-counterfeiting detection, one or more unit anti-counterfeiting blocks are selected for the anti-counterfeiting area, the gating frequency of the unit anti-counterfeiting block is detected, and the gating frequency is compared to see whether it is the same as the frequency corresponding to the unit anti-counterfeiting block; if all are the same, it means that the product is authentic, otherwise, the product is fake.

[0015] The present invention has the following beneficial effects:

[0016] 1. The hot stamping film coding anti-counterfeiting method based on frequency selective surface of the present invention utilizes the good frequency selectivity of the frequency selective surface. By designing a frequency selective surface structure corresponding to the frequency and preparing a surface structure corresponding to the corresponding code on the cold stamping film based on the coding combination, an advanced anti-counterfeiting function can be achieved, which has the advantages of high anti-counterfeiting, good adaptability and low cost.

[0017] 2. The hot stamping film coding anti-counterfeiting method based on frequency selective surface described in the present invention has many design parameters, including micro unit structure, size, arrangement, material, etc., and various coding forms. It is difficult to imitate without knowing the original design parameters, and the anti-counterfeiting method is reliable.

[0018] 3. The flexible cold stamping film with anti-counterfeiting marks prepared in the anti-counterfeiting method of hot stamping film coding based on frequency selective surface described in the present invention has the advantages of convenience, flexibility, good adaptability, low cost, etc. It has a one-time feature and cannot be restored once damaged, and has good self-protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of an open rectangular ring resonant unit;

[0020] Figure 2 It is a schematic diagram of the structure of an open circular ring resonator unit. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings, but it is not intended to be a basis for limiting the present invention.

[0022] Frequency Selective Surface (FSS) is a new type of artificially designed periodic structure array. It can achieve the passband of full transmission or the band-stop phenomenon of full reflection of the incident electromagnetic wave by changing the unit size and arrangement pattern. It has the advantages of high frequency selectivity, simple device structure and small size, and good angular stability. Therefore, it is widely used in the design and development of communication devices.

[0023] The present invention provides a hot stamping film coding anti-counterfeiting method based on a frequency selective surface, which specifically comprises the following steps:

[0024] (1) In the frequency range of 100kHz~1MHz, randomly select 10 frequencies and encode them from small to large as 0-9. Theoretically, the frequency range can also be selected at will, but the higher the frequency (such as GHz, THz), the more expensive the detection equipment is, so low frequencies are preferred.

[0025] (2) Designing a set of resonant units corresponding to each frequency selected in step (1), the set of resonant units comprising a plurality of resonant units of the same shape arranged periodically, wherein the characteristics of the set of resonant units include the shape (e.g., open circular ring, open rectangular ring, etc.) and size parameters of the resonant units, and the periodic arrangement (e.g., square array, regular polygon array, etc.) and arrangement spacing parameters of the resonant units.

[0026] Figure 1The figure shows an open rectangular ring resonator unit, which can achieve the desired FSS frequency by changing the three dimensions of g, w, and l as well as the periodic arrangement parameters. For example, when g=0.4mm, w=0.4mm, l=5mm, the periodic arrangement is a square array with a spacing of 1mm, the FSS frequency is 200kHz; when g=1mm, w=0.8mm, l=8mm, the periodic arrangement is a square array with a spacing of 1.5mm, the FSS frequency is 100kHz.

[0027] (3) Design an anti-counterfeiting code, which is N digits from 0 to 9, where N ≥ 1.

[0028] (4) Select an area on the cold foil film as the anti-counterfeiting area, divide the anti-counterfeiting area into N unit anti-counterfeiting blocks, and sort the N unit anti-counterfeiting blocks in order of 1 to N, requiring each unit anti-counterfeiting block to correspond to a unique number; and correspond each unit anti-counterfeiting block to each digit of the anti-counterfeiting code described in step (3) digit by digit in the order of 1 to N.

[0029] (5) According to the number corresponding to each unit anti-counterfeiting block in the anti-counterfeiting area and the corresponding relationship between the number and the frequency in step (1), the frequency corresponding to each unit anti-counterfeiting block is determined; according to the characteristics of the resonant unit set corresponding to the frequency designed in step (2), a corresponding resonant unit set is prepared in each unit anti-counterfeiting block area on the cold stamping film.

[0030] The specific preparation method is: first, a layer of metal film is deposited on the cold stamping film, and then the above-mentioned resonance unit set is prepared on the metal film by laser etching technology; or a mask plate of the resonance unit set can be prepared in advance, and then the metal resonance unit set is directly deposited on the cold stamping film through the mask plate.

[0031] (6) Transfer the cold stamping film with the anti-counterfeiting area to the surface of the product. The substrate of the product cannot be metal. Its materials can include PVC, acrylic, cardboard, wood, cloth, etc., and its thickness cannot exceed 10mm.

[0032] (7) During anti-counterfeiting detection, for the anti-counterfeiting area, the gating frequencies of the 1st to Nth unit anti-counterfeiting blocks are detected in sequence in the order of the bit numbers 1 to N; and the gating frequencies are compared one by one to see if they are the same as the frequencies corresponding to the unit anti-counterfeiting blocks; if all are the same, it means that the product is authentic, otherwise, the product is fake.

[0033] When comparing the frequencies one by one, if it is found that the frequencies are different, you can stop comparing and directly judge that the product is fake.

[0034] In order to reduce the workload of anti-counterfeiting detection, one or more of 1 to N anti-counterfeiting unit blocks can be randomly selected for detection. Once the frequencies are found to be different, the comparison can be stopped and the product can be directly judged to be fake.

[0035] Embodiment 1: A hot stamping film coding anti-counterfeiting method based on a frequency selective surface comprises the following steps:

[0036] In the frequency range of 100kHz~1MHz, 10 frequencies are selected as shown in Table 1, and their codes are 0~9 respectively.

[0037] Table 1 Frequency selected in Example 1

[0038] Frequency (kHz) 100 110 120 130 140 150 160 170 180 190 coding 0 1 2 3 4 5 6 7 8 9

[0039] The resonant unit set corresponding to each frequency selected in the design step (1) is a bandpass FSS structure. The resonant unit structure is as follows: Figure 1 The figure shows an open rectangular ring, arranged in a square array, with detailed parameters of the resonant unit and array spacing. p As shown in the following table:

[0040] 100 110 120 130 140 150 160 170 180 190 1 1 0.8 0.75 0.66 0.52 0.5 0.48 0.45 0.45 0.8 0.8 0.6 0.6 0.55 0.5 0.5 0.45 0.45 0.4 8 7.5 7.3 7 7 6.75 6.5 6 5.4 5 1.5 1.5 1.5 1.35 1.35 1.3 1.3 1 1 1

[0041] The design security code is 136210042.

[0042] Select an area on the cold foil film as the anti-counterfeiting area, divide the anti-counterfeiting area into 9 unit anti-counterfeiting blocks, and sort them according to the digits 1 to 9. Each unit anti-counterfeiting block corresponds to a digit of the anti-counterfeiting code 136210042 digit by digit.

[0043] Determine the frequency corresponding to each unit anti-counterfeiting block, as shown in Table 3:

[0044] Table 3 Correspondence between unit anti-counterfeiting blocks and frequencies in Example 1

[0045] Position number 1 2 3 4 5 6 7 8 9 coding 1 3 6 2 1 0 0 4 2 Frequency (kHz) 110 130 160 120 110 100 100 140 120

[0046] Then, according to the characteristics of the resonant unit set corresponding to the frequency designed in step (2), a corresponding resonant unit set is prepared in each unit anti-counterfeiting block area on the cold stamping film.

[0047] (6) The cold stamping film with the anti-counterfeiting area is transferred to the surface of the product, and its base material is cardboard with a thickness of 3mm.

[0048] (7) During anti-counterfeiting detection, the gating frequencies of the 1st to 9th anti-counterfeiting blocks in the anti-counterfeiting area are detected in sequence according to the digits from 1 to 9; and the gating frequencies are compared one by one to see if they are the same as the frequencies corresponding to the digits in the corresponding digits on the anti-counterfeiting code; if all are the same, it means that the product is authentic, otherwise, the product is fake.

[0049] Embodiment 2: A hot stamping film coding anti-counterfeiting method based on a frequency selective surface, comprising the following steps:

[0050] In the frequency range of 100kHz~1MHz, 10 frequencies are selected as shown in Table 4, and their codes are 0~9 respectively.

[0051] Table 4 Selected frequencies of Example 2

[0052] Frequency (kHz) 200 210 220 230 240 250 260 270 280 290 coding 0 1 2 3 4 5 6 7 8 9

[0053] The resonant unit set corresponding to each frequency selected in the design step (1) is a bandpass FSS structure. The resonant unit structure is as follows: Figure 2 The figure shows an open circular ring, arranged in a square array, with detailed parameters of the resonant unit and the distance between the center and the center. p As shown in the following table:

[0054] Table 5 Resonance unit set parameters of Example 2

[0055] 200 210 220 230 240 250 260 270 280 290 <![CDATA[ r 1]]> 1.5 1.5 1.4 1.4 1.3 1.3 1.3 1 1 1 <![CDATA[ r 2]]> 1.8 1.8 1.8 1.7 1.5 1.5 1.4 1.3 1.25 1.2 0.5 0.45 0.4 0.4 0.35 0.3 0.3 0.3 0.25 0.25 5 5 5 4 4 3.8 3.5 3.5 3 3

[0056] The design security code is 071202810319.

[0057] Select an area on the cold foil film as the anti-counterfeiting area, divide the anti-counterfeiting area into 12 unit anti-counterfeiting blocks, and arrange them in order from 1 to 12. Each unit anti-counterfeiting block corresponds to a number in the anti-counterfeiting code 071202810319 digit by digit.

[0058] Determine the frequency corresponding to each unit anti-counterfeiting block, as shown in Table 5:

[0059] Table 5 Correspondence between unit anti-counterfeiting blocks and frequencies in Example 2

[0060] Position number 1 2 3 4 5 6 7 8 9 10 11 12 coding 0 7 1 2 0 2 8 1 0 3 1 9 Frequency (kHz) 200 270 210 220 200 220 280 210 200 230 210 290

[0061] Then, according to the characteristics of the resonant unit set corresponding to the frequency designed in step (2), a corresponding resonant unit set is prepared in each unit anti-counterfeiting block area on the cold stamping film.

[0062] (6) The cold stamping film with the anti-counterfeiting area is transferred to the surface of the product, and its base material is an acrylic plate with a thickness of 2mm.

[0063] (7) During anti-counterfeiting detection, for the anti-counterfeiting area, one or more of 1 to 12 anti-counterfeiting blocks are randomly selected in the order of 1 to 12 positions for detection. Once the frequencies are found to be different, no further comparison is required and the product can be directly judged to be fake.

[0064] The present invention can be modified in many ways that are obvious to those skilled in the art, and such modifications are not considered to depart from the scope of the present invention. All such modifications that are obvious to those skilled in the art are intended to be included within the scope of the present claims.

Claims

1. A hot stamping film coding anti-counterfeiting method based on frequency selective surface, characterized in that: The following steps are involved: In the frequency range of 100kHz~1MHz, 10 frequencies are randomly selected and encoded as 0-9 from small to large. (2) designing a resonant unit set corresponding to each frequency selected in step (1), the resonant unit set comprising a plurality of resonant units of the same shape and arranged periodically; (3) Design an anti-counterfeiting code, which is N digits from 0 to 9, where N ≥ 1; (4) Select an area on the cold foil film as the anti-counterfeiting area, divide the anti-counterfeiting area into N unit anti-counterfeiting blocks, and sort the N unit anti-counterfeiting blocks in order of 1 to N, requiring each unit anti-counterfeiting block to correspond to a unique digit; and correspond each unit anti-counterfeiting block to each digit of the anti-counterfeiting code described in step (3) digit by digit in the order of 1 to N; (5) According to the number corresponding to each unit anti-counterfeiting block in the anti-counterfeiting area and the corresponding relationship between the number and the frequency in step (1), the frequency corresponding to each unit anti-counterfeiting block is determined; according to the characteristics of the resonant unit set corresponding to the frequency designed in step (2), a corresponding resonant unit set is prepared in each unit anti-counterfeiting block area on the cold stamping film; (6) Transfer the cold stamping film with the anti-counterfeiting area to the surface of the product. The substrate of the product must not be metal and the thickness must not exceed 10 mm; (7) During anti-counterfeiting detection, one or more unit anti-counterfeiting blocks are selected for the anti-counterfeiting area, the gating frequency of the unit anti-counterfeiting block is detected, and the gating frequency is compared to see whether it is the same as the frequency corresponding to the unit anti-counterfeiting block; if all are the same, it means that the product is authentic, otherwise, the product is fake.

2. The anti-counterfeiting method of hot stamping film coding based on frequency selective surface according to claim 1, characterized in that: The characteristics of the resonant unit set in step (2) include the shape and size parameters of the resonant units, as well as the periodic arrangement and arrangement spacing of the resonant units.

3. The anti-counterfeiting method of hot stamping film coding based on frequency selective surface according to claim 1, characterized in that: The specific preparation method of preparing the corresponding resonant unit set in each unit anti-counterfeiting block area on the cold stamping film in step (5) is: firstly, a layer of metal film is deposited on the cold stamping film, and then the above-mentioned resonant unit set is prepared on the metal film by laser etching technology.

4. The anti-counterfeiting method of hot stamping film coding based on frequency selective surface according to claim 1, characterized in that: The specific preparation method of preparing the corresponding resonant unit set in each unit anti-counterfeiting block area on the cold stamping film in step (5) is: preparing a mask plate of the resonant unit set in advance, and then directly depositing the metal resonant unit set on the cold stamping film through the mask plate.

5. The anti-counterfeiting method of hot stamping film coding based on frequency selective surface according to claim 1, characterized in that: The material of the product in step (6) is PVC, acrylic, cardboard, wood or cloth.

6. The anti-counterfeiting method of hot stamping film coding based on frequency selective surface according to claim 1, characterized in that: When performing frequency comparison in step (7), once it is found that a certain selection frequency is different from the frequency corresponding to the anti-counterfeiting block of the unit, the comparison will not be continued and the product will be directly judged to be fake.

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