Method for forming a PUF (PHYSICAL UNCLONABLE FUNCTION) film using DNA, and the PUF film formed thereby.

Abstract

PUF film is formed by preparing biopolymers extracted from plants and animals, mixing the biopolymers with a solvent to produce a PUF film solution, and coating the PUF film solution onto a substrate.

Description

[Technical Field]

[0001] This invention relates to a PUF film that can authenticate the authenticity of a work by utilizing a physical copy-prevention function in the work. [Background technology]

[0002] An analysis of the Organization for Economic Cooperation and Development (OECD)'s "Trends in Trade in Counterfeit Goods Report" estimates that global losses from counterfeit goods amounted to $464 billion in 2019. This is comparable to the size of the global semiconductor market ($412.3 billion in 2019), indicating the enormous scale of losses caused by counterfeit goods. In South Korea, the loss of sales due to counterfeit goods in the overseas export process is estimated at 22 trillion won. The loss of jobs due to the decrease in sales is estimated at 31,753, and the reduction in corporate tax and individual income tax is estimated at 416.9 billion won. South Korea is among the top 10 countries affected by counterfeit goods. The range of counterfeit goods has also expanded significantly, from luxury goods and fine items to pharmaceuticals, cosmetics, food, and works of art in recent years.

[0003] Recently, the domestic art auction market has been expanding explosively. In 2021, eight domestic auctioneers auctioned off a total of 324.9 billion won, more than 2.8 times the 115.3 billion won in 2020. This art market is expected to continue growing in the future.

[0004] In the market for tangible assets such as fine art and masterpieces, the authenticity of a work significantly impacts its value. This makes them targets for forgers, and as the tangible asset market grows, the forgery market tends to expand as well.

[0005] To address this counterfeiting problem, methods are used to identify the authenticity of artworks by inserting or attaching QR codes, RFID, or NFC chips. However, the text information embedded in QR codes, RFID, and NFC chips can be easily duplicated and transferred to other chips, making them virtually 100% replicable. To solve this, proposals utilizing NFT technology have been put forward, but apart from NFTs themselves, they cannot guarantee the authenticity of the actual artwork, raising concerns that the original artwork could be replaced or counterfeited. [Overview of the project] The problem to be solved

[0006] The objective of this invention is to provide a method for forming a PUF film that can be easily formed on artwork.

[0007] Another object of the present invention is to provide a PUF film formed by the method for forming the PUF film described above.

[0008] However, the problems that this invention aims to solve are not limited to those mentioned above, and can be extended in various ways without departing from the spirit and scope of this invention. [Means for solving the problem]

[0009] To achieve the objectives of the present invention, a method for producing a PUF film according to one aspect of the present invention is characterized by comprising the steps of: preparing a biopolymer extracted from plants or animals; mixing the biopolymer with a solvent to produce a PUF film solution; and coating the PUF film solution onto a substrate.

[0010] In one embodiment, the biopolymer is a DNA polymer.

[0011] In one embodiment, the biopolymer is a DNA polymer extracted from salmon.

[0012] In one embodiment, the DNA polymer has a double-stranded DNA structure, the contour length of the DNA polymer is 600 nm to 700 nm, and the persistence length of the DNA polymer is 50 nm or less.

[0013] In one embodiment, the PUF film solution has a nematic liquid crystal phase.

[0014] In one embodiment, the concentration of the PUF film solution is adjusted so that the PUF film solution has a nematic liquid crystal phase.

[0015] In one embodiment, the concentration of the PUF film is 40 mg / mL to 140 mg / mL.

[0016] In one embodiment, the solvent is water.

[0017] In one embodiment, the manufacturing method further includes the step of adding a fluorescent dye to the PUF film solution.

[0018] In one embodiment, the fluorescent dye is at least one selected from the group consisting of DAPI, AO, and CV.

[0019] In one embodiment, when the concentration of the PUF film solution is 100 mg / mL, the fluorescent dye is added in an amount of 10 μg per 1 mL of the PUF film solution.

[0020] In one embodiment, the step of coating the substrate with the PUF film solution involves applying shear stress to the PUF film solution using a stress application means.

[0021] In one embodiment, the stress application means is a paintbrush.

[0022] In one embodiment, the pattern density of the PUF film is adjusted by the thickness of the PUF film solution.

[0023] In one embodiment, as the thickness of the PUF film solution decreases, the pattern density of the PUF film increases, and as the thickness of the PUF film solution increases, the pattern density of the PUF film decreases.

[0024] In one embodiment, the substrate includes glass or an organosilicon compound (PDMS).

[0025] In one embodiment, the substrate has a flat or curved surface.

[0026] In one embodiment, the step of coating the PUF film solution on the substrate includes covering a patterned soft mask on the substrate and coating the PUF film solution along the pattern of the soft mask.

[0027] In one embodiment, the PUF film solution is coated on the substrate by a 3D printer.

[0028] In one embodiment, the manufacturing method further includes evaporating the solvent contained in the PUF film solution after coating the PUF film solution on the substrate.

[0029] In one embodiment, while the solvent evaporates, the pattern of the PUF film is formed due to the buckling instability occurring in the PUF film solution.

[0030] To achieve the object of the present invention, a PUF film according to another aspect of the present invention is characterized by being coated on a substrate and containing a biopolymer extracted from animals and plants.

[0031] In one embodiment, the biopolymer is a DNA polymer.

[0032] In one embodiment, the PUF film is as described in paragraph 22.

[0033] The label layer is covered and further comprises a cover layer containing an organosilicon compound. [Effects of the Invention]

[0034] The PUF film according to the present invention is equipped with a physical anti-counterfeiting (PUF) function. The PUF film can be formed on a substrate using simple methods such as a paintbrush or a 3D printer, and can be utilized optically rather than electronically, making it easy for artists and other creators to form and use. Furthermore, the PUF film is 1 cm thick. 2 Covering a square substrate costs less than $1 and takes less than 10 minutes, making the PUF film an easy and economical option. Furthermore, the PUF film is mechanically, physically, and chemically robust, durable for long-term use, and can avoid damaging the original material.

[0035] Since the PUF film can distinguish genuine items from fakes, the risk of genuine items being replaced with counterfeits during storage, distribution, and exhibition can be completely eliminated. Furthermore, since works on which the PUF film has been properly formed are immediately recognized as genuine, the credibility of the authentication is ensured, and disputes between sellers, consumers, and platforms during the process of trading works can be prevented in advance.

[0036] Furthermore, the PUF film solution for forming the PUF film can be manufactured by mixing DNA polymers extracted from plants and animals with a solvent such as water. These DNA polymers can be produced indefinitely from plants and animals, making raw material availability easy. They can be manufactured through a simple process by stirring them with water at room temperature. This reduces the cost of the PUF film solution.

[0037] However, the effects of the present invention are not limited to those described above, and can be extended in various ways without departing from the spirit and scope of the present invention. [Brief explanation of the drawing]

[0038] [Figure 1] Figure 1 is a plan view illustrating a substrate on which a PUF film according to one embodiment of the present invention is formed.

[0039] [Figure 2] Figure 2 is a cross-sectional view illustrating an example of the PUF film shown in Figure 1.

[0040] [Figure 3] Figure 3 is a cross-sectional view illustrating another example of the PUF film shown in Figure 1.

[0041] [Figure 4] Figure 4 is a sequence diagram illustrating a method for forming a PUF film according to one embodiment of the present invention.

[0042] [Figure 5] Figure 5 is a diagram illustrating the formation method shown in Figure 4. [Figure 6] Figure 6 is a diagram illustrating the formation method shown in Figure 4. [Figure 7] Figure 7 is a diagram illustrating the formation method shown in Figure 4. [Figure 8] Figure 8 is a diagram illustrating the formation method shown in Figure 4. [Figure 9] Figure 9 is a diagram illustrating the formation method shown in Figure 4. [Figure 10] Figure 10 is a diagram illustrating the formation method shown in Figure 4.

[0043] [Figure 11] Figure 11 is a sequence diagram illustrating a method for forming a PUF film according to another embodiment of the present invention.

[0044] [Figure 12] Figure 12 is a diagram illustrating the formation method shown in Figure 11.

[0045] [Figure 13] Figure 13 is a sequence diagram illustrating a method for forming a PUF film according to yet another embodiment of the present invention. Specific details for implementing the invention

[0046] With respect to the embodiments of the present invention shown herein, specific structural or functional descriptions are provided merely as examples for the purpose of illustrating the embodiments of the present invention, and the embodiments of the present invention can be carried out in various forms and should not be interpreted as being limited to the embodiments described herein.

[0047] The present invention can be modified in various ways and may take many forms. Specific embodiments are illustrated in the drawings and described in detail in the text. However, this should be understood not as an attempt to limit the invention to any particular disclosure, but rather as encompassing all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the invention.

[0048] Terms such as "first," "second," etc., are used to describe various components, but the components should not be limited by such terms. The terms are used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may refer to the second component, and similarly, the second component may refer to the first component.

[0049] When one component is described as being "linked" or "connected" to another component, it should be understood that this can mean that the other component is directly linked or connected to it, or that another component may exist in between. On the other hand, when one component is described as being "directly linked" or "directly connected" to another component, it should be understood that there is no other component in between. Other expressions describing the relationships between components, such as "between" and "immediately between," or "adjacent to" and "directly adjacent to," should be analyzed in the same way.

[0050] The terms used in this application are used solely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “includes” or “having” are intended to specify the existence of features, figures, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood not to preemptively exclude the existence or possibility of adding one or more other features, figures, steps, actions, components, parts, or combinations thereof.

[0051] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as they would be generally understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as an ideal or overly formal meaning unless explicitly defined herein.

[0052] On the other hand, if a certain embodiment can be embodied in a different way, the functions or operations specified within a particular block may occur differently from the procedures specified in the flowchart. For example, two consecutive blocks may actually occur substantially simultaneously, and depending on the functions or operations involved, the blocks may also occur in reverse order.

[0053] Preferred embodiments of the present invention will be described in more detail below with reference to the attached drawings. Identical components in the drawings are denoted by the same reference numerals, and redundant descriptions of the same components are omitted.

[0054] Figure 1 is a plan view illustrating a substrate on which a PUF film according to one embodiment of the present invention is formed; Figure 2 is a cross-sectional view illustrating an example of the PUF film of Figure 1; and Figure 3 is a cross-sectional view illustrating another example of the PUF film of Figure 1.

[0055] As shown in Figures 1 and 2, the PUF film 100 according to one embodiment of the present invention is formed on a substrate (SUB).

[0056] The substrate (SUB) is the genuine surface used to prevent counterfeiting, and is the surface on which the PUF film 100 is formed. For example, the substrate (SUB) can refer to the surface of a work of art, a masterpiece, a luxury item, a pharmaceutical product, a cosmetic product, or a food product. Since the PUF film 100 does not physically or chemically damage the substrate (SUB), the substrate (SUB) can be the genuine surface itself.

[0057] PUF film 100 is a film equipped with a physical unclonable function and is formed immediately after the genuine article is produced or authenticated as genuine. Since PUF film 100 does not damage the substrate (SUB) at all, there is no risk of the genuine article being damaged by PUF film 100, and PUF film 100 can distinguish genuine articles from fakes, completely blocking the risk of genuine articles being replaced with counterfeits during storage, distribution, and exhibition. Furthermore, since works on which PUF film 100 has been properly formed are immediately evaluated as genuine, the credibility of authentication is ensured, and disputes between sellers, consumers, and platforms during the process of trading works can be prevented in advance.

[0058] Furthermore, as will be described later, the PUF film 100 can be easily formed using a paintbrush or the like, and can be used optically rather than electronically, which is mainly used in semiconductor manufacturing. Therefore, it can be easily formed and used by artists and other creators.

[0059] As shown in Figure 1, the PUF film 100 is formed on the corner (edge) of the substrate (SUB), but the position where the PUF film 100 is formed is not limited to this. For example, since the PUF film 100 can be manufactured transparently, in this case the PUF film 100 can be formed on the substrate (SUB) without any positional restrictions.

[0060] Furthermore, as shown in Figure 2, the PUF film 100 can be implemented solely as a label layer without a separate cover layer. The PUF film 100 of the present invention is robust in physical environments such as impact, warping, high temperatures, and low temperatures, and is also robust in chemical environments such as inorganic solvents, organic solvents, moisture, and humidity. Therefore, the pattern formed within the PUF film 100 can remain undamaged even without a separate cover layer.

[0061] As shown in Figure 3, in another embodiment, the PUF film 100 includes a label layer (LL) and a cover layer (CL). The label layer (LL) has the pattern of the PUF film 100 formed on it, and the cover layer (CL) covers the label layer (LL). For example, the cover layer (CL) may include an organosilicon compound (e.g., PDMS), and the cover layer (CL) can further improve the reliability of the PUF film 100.

[0062] Figure 4 is a sequence diagram illustrating a method for forming a PUF film according to one embodiment of the present invention, and Figures 5 to 10 are diagrams illustrating the formation method shown in Figure 4.

[0063] As shown in Figure 4, a method for forming a PUF film according to one embodiment of the present invention (S1000) includes the steps of: preparing a biopolymer extracted from plants or animals (S100); mixing the biopolymer with a solvent to produce a PUF film solution (S300); adding a fluorescent dye to the PUF film solution (S500); coating the PUF film solution onto a substrate with a brush (S700); and evaporating the solvent contained in the PUF film solution (S900).

[0064] As shown in Figures 4 and 5, the biopolymer extracted from plants and animals is prepared (S100). In one embodiment, the biopolymer is a DNA polymer, a protein polymer, an enzyme polymer, etc. For example, a DNA polymer is a substance suitable for forming a high-entropy-based random pattern, and preferably, the biopolymer can be a DNA polymer.

[0065] In one embodiment, the biopolymer is a DNA polymer extracted from salmon. The DNA polymer can be extracted directly or obtained commercially (e.g., from Sigma-Aldrich). The DNA polymer has a duplex DNA structure and approximately 2000 base pairs. In the case of the DNA polymer extracted from salmon, the contour length is approximately 600 nm to 700 nm, preferably approximately 680 nm, and the persistence length is approximately 50 nm or less.

[0066] Referring further to Figure 4, the biopolymer is mixed with a solvent to produce a PUF film solution (S300). The solvent includes various solvents that dissolve the biopolymer, and in one embodiment, when the biopolymer is a DNA polymer, the solvent is water.

[0067] The PUF film solution has a nematic liquid crystal phase. DNA polymer chains condensed according to Onsager's criteria can express a liquid crystal phase within a specific concentration range. Using this, the concentration of the PUF film solution is adjusted so that the PUF film solution has a nematic liquid crystal phase. For example, the concentration of the PUF film solution is adjusted by the type of biopolymer, the mixing ratio of the biopolymer, and the mixing ratio of the solvent.

[0068] In one embodiment, when using the DNA polymer extracted from the salmon described above, the concentration of the PUF film solution is approximately 40 mg / mL to 140 mg / mL. By satisfying the above concentration range, the PUF film solution can have a nematic liquid crystal phase.

[0069] Specifically, a PUF film solution sample with a concentration of 100 mg / mL was prepared by mixing 100 mg of DNA polymer extracted from salmon (Sigma-Aldrich, 1,300,000 g / mol) with 1 mL of water and stirring at room temperature.

[0070] Referring to Figures 4 and 6, a fluorescent dye is added to the PUF film solution (S500). In one embodiment, the fluorescent dye is a substance that binds to the biopolymer and exhibits fluorescence. For example, the fluorescent dye contains an aromatic ring and is inserted between the base sequences of the DNA polymer.

[0071] As shown in Figure 6, the fluorescent dye inserted into the DNA polymer can induce dichroic fluorescence depending on the polarization of the irradiated light. Examples of the fluorescent dyes include DAPI (4',6-diamidino-2-phenylindole), AO (acridine orange), and CV (crystal violet).

[0072] The amount of the fluorescent dye added is appropriately set within a range in which dichroic fluorescence is smoothly induced. In one embodiment, when the concentration of the PUF film solution is approximately 100 mg / mL, approximately 10 μg of the fluorescent dye can be added per 1 mL of the PUF film solution.

[0073] When the PUF film to which the fluorescent dye was added was exposed to linearly polarized light at a 45-degree angle to the shear stress direction, a band of fluorescence was observed, as shown in Figure 6. Furthermore, when this was rotated 90 degrees and exposed to polarized light, the band of fluorescence was observed to be reversed. Since the fluorescent dye can add fluorescence without changing the pattern of the PUF film, the security level of the PUF film can be further improved.

[0074] On the other hand, the step of adding the fluorescent dye (S500) is selective. That is, in other embodiments, the step of adding the fluorescent dye can be omitted, and the PUF film formed thereby does not exhibit fluorescence.

[0075] As shown in Figures 4 and 7, shear stress is applied to the PUF film solution by a stress application means to coat the substrate with the PUF film solution (S700). In one embodiment, as shown in Figure 7, the stress application means is a brush, and the PUF film solution can be easily coated onto the substrate using the brush.

[0076] The substrate to which the PUF film is coated is not limited in material, shape, etc. For example, the substrate may be made of glass, plastic, or the like, and may contain glass or organosilicon compounds (PDMS). Furthermore, the substrate may have a flat or curved surface, and the PUF film solution can be coated onto a cylindrical substrate as well. As a result, the PUF film of the present invention can be formed not only on two-dimensional planar works but also on three-dimensional three-dimensional works.

[0077] As shown in Figures 4 and 8, the solvent contained in the PUF film solution coated on the substrate is evaporated (S900).

[0078] As shown in Figure 8a, the substrate was coated with a PUF film solution under shear stress and then observed with a polarizing optical microscope (POM). Immediately after applying the shear stress, the nematic liquid crystal phase of the PUF film solution was observed as uniaxially aligned and dark due to the shear stress.

[0079] Subsequently, as shown in Figure 8c, we observed that buckling instability occurred within the PUF film solution due to the elastic force of the DNA strands while the solvent evaporated, resulting in the sequential formation of a pattern resembling a zebra's stripe.

[0080] As shown in Figure 8b, when a completely dried PUF film solution, with the solvent removed, is observed using a polarizing optical microscope equipped with a phase delay plate, a pattern of alternating blue and yellow bands is observed. The blue bands represent regions where the principal axes of DNA are aligned perpendicularly to the optical axis of the phase delay plate, while the yellow bands represent regions where the principal axes of DNA are aligned parallel to the optical axis of the phase delay plate.

[0081] As shown in Figure 8d, the observed blue and yellow band POM images can be converted into digital images by applying image processing techniques. These digital images can then be used to extract the ridge ends and bifurcations, which are characteristic features of fingerprints.

[0082] As shown in Figure 9, the captured digital images were statistically analyzed to evaluate the reliability of the PUF film formed by the method of the present invention described above. As shown in Figure 9a, 0.01 mm 2Using 100 POM images with a given area, we extracted ridge end codes and bifurcation codes, and used them for statistical analysis.

[0083] As shown in Figure 9b, the number of extracted ridge ends (endings) and bifurcations (bifurcations) was measured to analyze bit uniformity. The analysis results showed that the number of ridge ends (endings) was measured at 149.5 ± 40.5 per unit area, resulting in a bit uniformity of 0.508 ± 0.0886. The number of bifurcations (bifurcations) was measured at 323.1 ± 41.4 per unit area, resulting in a bit uniformity of 0.508 ± 0.0417. Both the ridge ends (endings) and bifurcations (bifurcations) converged to the ideal bit uniformity value of 0.5, confirming the high security performance of the PUF film of the present invention.

[0084] As shown in Figures 9c and 9d, the Ending code was converted to a binary code of size 25x25, and the Bifurcation code was converted to a binary code of size 36x36, after which the Lempel-Ziv (LZ) entropy was calculated. The LZ entropy was calculated by combining the LZ complexity, which reflects the number of distinct binary sequence combinations, and bit uniformity. The calculation results showed that the average LZ entropy of the binary sequence for the Ending code was 0.903, with a standard deviation of 0.059. The average LZ entropy of the binary sequence for the Bifurcation code was 0.877, with a standard deviation of 0.025. The average LZ entropy values ​​of the Ending code and Bifurcation code were approximately at the 85th percentile level, close to the ideal 100%, confirming that there was no correlation between the binary codes obtained from different PUF films. Furthermore, the low standard deviation confirmed a consistent level of complexity across different PUF films.

[0085] As shown in Fig. 9e, after converting the ridge end code (Ending code) into a binary code with a size of 25×25 and the bifurcation code (Bifurcation code) into a binary code with a size of 36×36, the Hamming distance (HD) was calculated. From the inter-sample Hamming distance (inter HD), uniqueness, which is an index for evaluating whether there are bit values that are independently causally unrelated between the patterns of the PUF film, was analyzed. The ideal inter HD value converges to 0.5. From the intra-sample Hamming distance (intra HD), reliability, which is an index for evaluating whether the unique bits of the PUF film pattern are maintained constant due to changes in the external environment, was analyzed. The ideal intra HD value converges to 0. The calculation results showed that the histograms obtained from the calculated inter HD and intra HD values have a Gaussian distribution, and the mean (m) of each graph is approximately 0.494, and the standard deviation (s) is calculated to be approximately 0.03 or less.

[0086] As shown in Fig. 9f, this is a numerical index representing the amount of information that can be encapsulated per unit area, the encoding capacity (EC = 2 (m(1-m)) s -2 ). Substituting and calculating, it was confirmed that as the area of the PUF film increases, the amount of information in the pattern increases, and it was confirmed that per unit area of 1 mm 2 can hold an amount of information of about 10 28,000 .

[0087] Also, based on the distributions of inter HD and intra HD shown in Fig. 9e, the false positive rate (FPR) and false negative rate (FNR) can be calculated. The calculation results are as follows: the FPR of the ridge end (ending) Ending = 4.9×10 -8 =, the FPR of the bifurcation point (bifurcation) Bifurcation = 1.23×10 -13 , the FNR of the ridge end (ending) Ending = 5.45×10 -8FNR at bifurcation Bifurcation = 1.01 × 10 -13 This is calculated as follows: When verifying the authenticity of the PUF film using hierarchical recognition, 10 -21 The misrecognition rate was low, so we confirmed the reproducibility of the PUF film, which is that identical digital codes are generated from identical PUF films, while clearly distinct digital codes are generated from different PUF films.

[0088] Referring to Figure 10, the pattern density of the PUF film can be adjusted by changing the thickness of the PUF film solution being coated. In one embodiment, the pattern density of the PUF film increases as the thickness of the PUF film solution decreases, and decreases as the thickness of the PUF film solution increases. In other words, the pattern density of the PUF film is inversely proportional to the thickness of the PUF film solution. For example, if the pattern density of the PUF film has a large periodicity of about 10 μm, the pattern can be detected by a mobile phone camera. On the other hand, if the pattern density of the PUF film has a small periodicity of less than about 1 μm, the pattern can be detected by an atomic force microscope (AFM). That is, the security level of the PUF film can be easily adjusted by adjusting the thickness of the PUF film solution being coated.

[0089] Figure 11 is a sequence diagram illustrating a method for forming a PUF film according to another embodiment of the present invention, and Figure 12 is a diagram illustrating the formation method shown in Figure 11.

[0090] As shown in Figures 11 and 12, a method for forming a PUF film according to another embodiment of the present invention (S2000) includes the steps of: preparing a biopolymer extracted from plants or animals (S100); mixing the biopolymer with a solvent to produce a PUF film solution (S300); adding a fluorescent dye to the PUF film solution (S500); covering a patterned soft mask on a substrate (S710); coating the PUF film solution along the pattern of the soft mask (S730); and evaporating the solvent contained in the PUF film solution (S900).

[0091] However, the method for forming the PUF film in Figure 11 (S2000) is substantially the same as the method for forming the PUF film in Figure 4 (S1000), except for steps S710 and S730.

[0092] As shown in Figures 12a, 12b, and 12c, after preparing the aforementioned PUF film solution and patterned soft mask, the soft mask is placed on the substrate, and the PUF film solution is coated along the pattern of the soft mask by applying shear stress with a brush. As shown in Figure 12d, it can be observed that the pattern of the PUF film is well formed regardless of the pattern of the soft mask. This ensures the design versatility of works utilizing PUF film.

[0093] Figure 13 is a sequence diagram illustrating a method for forming a PUF film according to yet another embodiment of the present invention.

[0094] As shown in Figure 13, a method for forming a PUF film according to another embodiment of the present invention (S2000) includes the steps of: preparing a biopolymer extracted from plants or animals (S100); mixing the biopolymer with a solvent to produce a PUF film solution (S300); adding a fluorescent dye to the PUF film solution (S500); coating the PUF film solution with a 3D printer (S750); and evaporating the solvent contained in the PUF film solution (S900).

[0095] However, the method for forming the PUF film in Figure 13 (S3000) is substantially the same as the method for forming the PUF film in Figure 4 (S1000), except for step S750.

[0096] After preparing the aforementioned PUF film solution, it can be applied to a 3D printer to form a PUF film on a substrate using 3D printing technology. This ensures the design versatility of works utilizing PUF film without the need for a separate soft mask.

[0097] According to embodiments of the present invention, a PUF film equipped with a physical anti-counterfeiting (PUF) function can be formed on a substrate using simple methods such as a paintbrush or a 3D printer, and can be utilized optically rather than electronically, making it easy for artists and other creators to form and utilize it. Furthermore, the PUF film is 1 cm 2 Covering a square substrate with PUF film costs less than $1 and takes less than 10 minutes, making it an easy and economical way to utilize PUF film. Furthermore, PUF film is mechanically, physically, and chemically robust, durable, and can avoid damaging the original material.

[0098] This allows for the identification of genuine items using PUF film, completely eliminating the risk of counterfeits replacing genuine items during storage, distribution, and exhibition. Furthermore, since works with properly formed PUF film are immediately recognized as genuine, the credibility of authentication is ensured, and disputes between sellers, consumers, and platforms during the trading process can be prevented.

[0099] Furthermore, the PUF film solution used to form the PUF film can be manufactured by mixing DNA polymers extracted from plants and animals with a solvent such as water. DNA polymers can be produced indefinitely from plants and animals, making raw material procurement easy. By stirring them with water at room temperature, the solution can be manufactured through a simple process. This further reduces the cost of the PUF film solution.

[0100] Having been described above with reference to embodiments, those skilled in the art will understand that the present invention can be modified and altered in various ways without departing from the spirit and scope of the invention as set forth in the following claims.

[0101] <Explanation of symbols>

[0102] 100: PUF film

Claims

1. The steps include preparing biopolymers extracted from plants and animals, The steps include: mixing the biopolymer with a solvent to produce a PUF film solution; A method for forming a PUF film, characterized by comprising the step of coating a substrate with the PUF film solution.

2. The method for forming a PUF film according to claim 1, characterized in that the biopolymer is a DNA polymer.

3. The method for forming a PUF film according to claim 2, characterized in that the biopolymer is a DNA polymer extracted from salmon.

4. The aforementioned DNA polymer has a double-stranded DNA structure, The contour length of the aforementioned DNA polymer is 600 nm to 700 nm. The method for forming a PUF film according to claim 3, characterized in that the persistence length of the DNA polymer is 50 nm or less.

5. The method for forming a PUF film according to claim 1, characterized in that the PUF film solution has a nematic liquid crystal phase.

6. The method for forming a PUF film according to claim 5, characterized in that the concentration of the PUF film solution is adjusted so that the PUF film solution has a nematic liquid crystal phase.

7. The method for forming a PUF film according to claim 6, characterized in that the concentration of the PUF film is 40 mg / mL to 140 mg / mL.

8. The method for forming a PUF film according to claim 1, characterized in that the solvent is water.

9. The method for forming a PUF film according to claim 1, further comprising the step of adding a fluorescent dye to the PUF film solution.

10. The method for forming a PUF film according to claim 9, characterized in that the fluorescent dye is at least one selected from the group consisting of DAPI, AO, and CV.

11. The method for forming a PUF film according to claim 10, characterized in that, when the concentration of the PUF film solution is 100 mg / mL, the fluorescent dye is added in an amount of 10 μg per 1 mL of the PUF film solution.

12. The method for forming a PUF film according to claim 1, characterized in that the step of coating the substrate with the PUF film solution is further characterized by applying shear stress to the PUF film solution using a stress application means.

13. The method for forming a PUF film according to claim 12, characterized in that the stress application means is a paintbrush.

14. The method for forming a PUF film according to claim 1, characterized in that the pattern density of the PUF film is adjusted by the thickness of the PUF film solution.

15. As the thickness of the PUF film solution decreases, the pattern density of the PUF film increases. The method for forming a PUF film according to claim 14, characterized in that the pattern density of the PUF film decreases as the thickness of the PUF film solution increases.

16. The method for forming a PUF film according to claim 1, characterized in that the substrate comprises glass or an organosilicon compound (PDMS).

17. The method for forming a PUF film according to claim 1, characterized in that the substrate has a planar or curved surface.

18. The step of coating the substrate with the PUF film solution is: The steps include covering the substrate with a patterned soft mask, A method for forming a PUF film according to claim 1, characterized by comprising the step of coating the PUF film solution along the pattern of the soft mask.

19. The method for forming a PUF film according to claim 1, characterized in that the PUF film solution is coated onto the substrate by a 3D printer.

20. The method for forming a PUF film according to claim 1, further comprising the step of coating the substrate with the PUF film solution and then evaporating the solvent contained in the PUF film solution.

21. The method for forming a PUF film according to claim 20, characterized in that the pattern of the PUF film is formed by buckling instability that occurs in the PUF film solution while the solvent evaporates.

22. A PUF film characterized by comprising a label layer coated on a substrate and containing biopolymers extracted from plants and animals.

23. The PUF film according to claim 22, characterized in that the biopolymer is a DNA polymer.

24. The PUF film according to claim 22, further comprising a cover layer that covers the label layer and contains an organosilicon compound.

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