Chiral photonic crystal toner and preparation method and application thereof

Abstract

The present application provides a kind of chiral photonic crystal toner and its preparation method and application, the chiral photonic crystal toner is composed of chiral photonic crystal microparticle and the luminous substance loaded in the chiral photonic crystal microparticle;The preparation method includes the following steps: liquid crystal polymer monomer, chiral dopant, luminous substance are mixed, and chiral photonic crystal polymer film loaded with luminous substance is obtained by polymerization, then it is crushed to obtain the chiral photonic crystal toner;The chiral photonic crystal microparticle has chiral structural color, and chiral structural color is generated from chiral photonic band gap.The chiral photonic crystal toner provided by the present application has the characteristics of chiral structural color and circularly polarized luminescence, and can greatly improve the information security in the application of anti-counterfeiting technology.

Description

Technical Field

[0001] This invention belongs to the field of optical materials technology, specifically relating to a chiral photonic crystal pigment, its preparation method, and its application. Background Technology

[0002] With the improvement of productivity, counterfeiting methods are also becoming increasingly sophisticated. Counterfeit products severely harm the interests of both producers and consumers during the commodity circulation process. Existing anti-counterfeiting technologies, including physical methods such as digital anti-counterfeiting verification, electronic tags, and anti-counterfeiting packaging, as well as chemical technologies, are characterized by ease of imitation and poor concealment, and are increasingly unable to meet actual needs. For example, holographic anti-counterfeiting and radio frequency anti-counterfeiting technologies are commonly used physical anti-counterfeiting methods in the market, but they suffer from high equipment and maintenance costs. For chemical anti-counterfeiting, chemiluminescence is more common, with visible light emission systems being the preferred choice. Visible light anti-counterfeiting can be identified by the naked eye, improving the convenience of identification, but it also reduces security and makes it easy to counterfeit. Furthermore, the organic luminescent dyes commonly used in chemiluminescent anti-counterfeiting often rely on the color of their emission, facing challenges such as poor stability and easy photobleaching leading to color loss. The structural color of photonic crystals can precisely avoid this problem.

[0003] Photonic crystals are a class of materials with periodically arranged microstructures of media with different refractive indices. The periodic distribution of refractive indices prevents light of a specific wavelength from passing through, resulting in reflection; this range of wavelengths is called the photonic bandgap. When the bandgap of a photonic crystal lies within the visible light region, it means that light of a certain frequency in the visible light band will be reflected, exhibiting a color visible to the naked eye in that band—the structural color. For chiral photonic crystal materials, the photonic bandgap exhibits chiral enantioselectivity, meaning it can selectively reflect left-handed or right-handed circularly polarized light while transmitting circularly polarized light of the opposite direction. Existing methods for anti-counterfeiting using photonic crystals mostly combine them with other anti-counterfeiting techniques, with relatively little development of the optical properties of photonic crystals themselves, especially chiral photonic crystals. Therefore, how to simply and quickly prepare a chiral photonic crystal and utilize its chiral optical properties in conjunction with optical anti-counterfeiting technology has become an urgent problem to be solved in this field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a chiral photonic crystal color powder, its preparation method, and its applications. The chiral photonic crystal color powder provided by this invention possesses the characteristics of chiral structural color and circularly polarized luminescence, and its application in anti-counterfeiting technology can greatly improve the security of information anti-counterfeiting encryption.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing chiral photonic crystal pigments, wherein the chiral photonic crystal pigments are composed of chiral photonic crystal microparticles and a luminescent substance loaded on the chiral photonic crystal microparticles;

[0007] The preparation method includes the following steps:

[0008] A liquid crystal polymer monomer, a chiral dopant, and a luminescent material are mixed and polymerized to obtain a chiral photonic crystal polymer film loaded with the luminescent material, which is then pulverized to obtain the chiral photonic crystal color powder.

[0009] The chiral photonic crystal particles possess chiral structural colors, which are generated from the chiral photonic bandgap.

[0010] The luminescent material, when loaded onto chiral photonic crystal microparticles, can produce circularly polarized luminescence.

[0011] The aforementioned chiral photonic crystal pigments possess chiral structural color and circularly polarized luminescence characteristics. While generating chiral structural color, the chiral photonic crystal microparticles provide a chiral environment for the luminescent material loaded within them, enabling the luminescent material to emit circularly polarized light. Furthermore, the luminescent material being loaded inside the microparticles reduces direct contact with air to some extent, increasing the stability of the luminescent dye. The combination of microparticles and luminescent material allows for selective emission into both visible and near-infrared light ranges, which can significantly enhance the security of information encryption and anti-counterfeiting technology.

[0012] Preferably, by weight, the liquid crystal polymer monomer comprises 80-120 parts, the chiral dopant comprises 0.8-4 parts, and the luminescent material comprises 0.1-1 parts.

[0013] The amount of liquid crystal polymer monomer can be 80, 85, 90, 95, 100, 105, 110, 115, or 120 parts, etc.; the amount of chiral dopant can be 0.8, 1, 1.5, 2, 2.5, 3, 3.5, or 4 parts, etc.; and the amount of luminescent material can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 part, etc., but is not limited to the values ​​listed above. Other unlisted values ​​within the above range are also applicable.

[0014] Preferably, the polymeric monomers include 1,4-bis[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene (C6M) and / or 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene (RM257).

[0015] Preferably, the chiral dopant includes any one or a combination of at least two of S5011, R5011, S811, or R811.

[0016] Preferably, the luminescent material is colorless or white when observed with the naked eye under visible light; the emission wavelength of the luminescent material is aligned with the center of the photonic bandgap of the chiral photonic crystal microparticle, and the half-width at half maximum (FWHM) of the emission wavelength of the luminescent material is smaller than the width of the photonic bandgap.

[0017] For example, the luminescent material can be: inorganic materials including silver-gold-selenium quantum dots, rare earth nanoparticles, and lanthanide-doped lead-cesium halide perovskites; organic materials including common blue dyes such as 9,10-diphenylanthracene. Furthermore, organic green or red dyes absorb light at slightly shorter emission wavelengths, thus producing color, but the color can be diluted by reducing the doping amount, thereby not affecting the structural color, and therefore can also be used.

[0018] Preferably, the mixing further includes mixing with a crosslinking agent and a photoinitiator.

[0019] Preferably, the crosslinking agent is 4-8 parts by weight and the photoinitiator is 1-3 parts by weight.

[0020] The crosslinking agent can be 4, 5, 6, 7 or 8 parts, etc., and the photoinitiator can be 1, 1.5, 2, 2.5 or 3 parts, etc., but is not limited to the values ​​listed above. Other unlisted values ​​within the above range are also applicable.

[0021] Preferably, the crosslinking agent comprises trimethylolpropane triacrylate (TMPTA) and / or 2-methyl-1,4-phenylenebis(4-(((4-(acryloyloxy)butoxy)carbonyl)oxy)benzoate (LC242).

[0022] Preferably, the photoinitiator comprises 2,2-dimethoxy-2-phenylacetophenone (I651) and / or methyl benzoate (MBF).

[0023] Preferably, the mixing further includes mixing with a solvent, and the mixing process further includes removing the solvent;

[0024] Preferably, the solvent includes dichloromethane.

[0025] Secondly, the present invention provides chiral photonic crystal pigments prepared by the preparation method described above.

[0026] Preferably, the chiral photonic crystal pigment has chiral structural color and circularly polarized luminescence characteristics in the visible light band and / or near-infrared band.

[0027] Thirdly, the present invention provides the application of chiral photonic crystal toners as described above in anti-counterfeiting technology.

[0028] Fourthly, the present invention also provides an anti-counterfeiting method, which includes the following steps:

[0029] (1) Fill the chiral photonic crystal toner as described above to form an anti-counterfeiting pattern;

[0030] (2) Observe the anti-counterfeiting pattern with the naked eye to obtain the first pattern, and then observe the first pattern through a circular polarizer whose application range covers the chiral structural color range of the chiral photonic crystal pigment, and observe the change of the first pattern.

[0031] The luminescent material in the chiral photonic crystal pigment is excited to obtain a second pattern. The second pattern is then observed through a circular polarizer whose range encompasses the luminescence range of the luminescent material in the chiral photonic crystal pigment, and changes in the second pattern are observed.

[0032] Preferably, after step (1), the method further includes filling the anti-counterfeiting pattern with chiral photonic crystal pigments (light-emitting materials loaded with near-infrared emission wavelengths aligned with the photonic bandgap) that are invisible to the naked eye with structural color; after observing the change in the second pattern, the third pattern is obtained by observing it with a near-infrared camera, and the change in the third pattern is observed by observing it through a circular polarizer of the chiral structural color range of the chiral photonic crystal pigments that are invisible to the naked eye.

[0033] Compared to existing anti-counterfeiting technologies that partially employ integral chiral photonic crystal films, the above-mentioned anti-counterfeiting method utilizes the randomness of dye loading within the voids of the thin film, emphasizing the anti-counterfeiting effect of non-repeatable patterns formed by irregular spatial distribution. In contrast, this invention primarily considers the diversity of patterns. By combining structural color and dye luminescence, the selection of different luminescence wavelengths further increases the difficulty and cost of counterfeiting, significantly improving the anti-counterfeiting effect.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] This invention provides a method for preparing chiral photonic crystal pigments. The resulting chiral photonic crystal pigments possess chiral structural color and circularly polarized light emission characteristics. While generating chiral structural color, the chiral photonic crystal microparticles provide a chiral environment for the luminescent material loaded within them, enabling the luminescent material to emit circularly polarized light. Furthermore, the luminescent material being loaded inside the microparticles reduces direct contact with air to a certain extent, increasing the stability of the luminescent dye. The combination of microparticles and luminescent material allows for selective emission into both visible and near-infrared light ranges, which can significantly improve the security of information anti-counterfeiting encryption when used in anti-counterfeiting technology. Attached Figure Description

[0036] Figure 1 Photoluminescence and transmittance spectra of the chiral photonic crystal pigments provided in Examples 1-2;

[0037] Figure 2 The circularly polarized emission spectra of the chiral photonic crystal pigments provided in Examples 1-2;

[0038] Figure 3 Photoluminescence and transmittance spectra of the chiral photonic crystal pigments provided in Examples 3-4;

[0039] Figure 4 The circularly polarized emission spectra of the chiral photonic crystal pigments provided in Examples 3-4;

[0040] Figure 5 A diagram illustrating the anti-counterfeiting effect of chiral structural color in the visible light range of the chiral photonic crystal pigment provided in Application Example 1.

[0041] Figure 6 A diagram illustrating the visible light range circularly polarized luminescence anti-counterfeiting effect of the chiral photonic crystal pigment provided in Application Example 1.

[0042] Figure 7 The near-infrared circularly polarized light emission anti-counterfeiting effect diagram of the chiral photonic crystal pigment provided in Application Example 1. Detailed Implementation

[0043] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0044] Example 1

[0045] This embodiment provides three types of chiral photonic crystal color powders and their preparation methods. The chiral photonic crystal color powders include chiral photonic crystal microparticles and luminescent materials loaded on the chiral photonic crystal microparticles; the structural color is in the visible light range.

[0046] The luminescent materials (with the maximum emission wavelength aligned with the center of the photon bandgap) are: blue luminescent dye (9,10-dibenzane), with a maximum emission wavelength of 430 nm and a half-width at half-maximum (WHM) of 80 nm; green luminescent dye (coumarin 6), with a maximum emission wavelength of 520 nm and a WHM of 70 nm; and red luminescent dye (Nile Red), with a maximum emission wavelength of 640 nm and a WHM of 100 nm.

[0047] The raw materials for preparing the chiral photonic crystal pigment include the following components in parts by weight:

[0048] 100 parts of liquid crystal polymer monomer C6M, 7.8 parts of crosslinking agent TMPTA, 2.5 parts of photoinitiator I651, 2, 3 or 4 parts of chiral dopant R5011, and 0.1 parts of luminescent material;

[0049] The chiral photonic crystal pigment has a photonic bandgap (structural color) with the center positions of the bandgap at 430 nm (corresponding to 4 parts of chiral dopant), 520 nm (corresponding to 3 parts of chiral dopant) and 640 nm (corresponding to 2 parts of chiral dopant), and the bandgap width is 150 nm.

[0050] The preparation method of the chiral photonic crystal pigment is as follows:

[0051] After the above-mentioned raw materials and dichloromethane (500 parts) were mixed evenly, the mixture was heated to 80°C to volatilize the dichloromethane. Then, the mixture was poured into a polymerization template and irradiated with ultraviolet light with a wavelength of 365 nm for 20 minutes to obtain a chiral photonic crystal polymer film. The chiral photonic crystal polymer film was then placed in a cutting machine for pulverization to obtain the three structural colors of chiral photonic crystal pigments, which were named R-blue pigment, R-green pigment and R-red pigment, respectively.

[0052] Example 2

[0053] This embodiment provides three chiral photonic crystal color powders and their preparation methods. The only difference from Embodiment 1 is that the chiral dopant R5011 is replaced with an equal weight proportion of chiral dopant S5011, while other conditions are the same as in Embodiment 1. The products are named S-blue color powder, S-green color powder, and S-red color powder, respectively.

[0054] The emission spectra, transmittance spectra, and circularly polarized emission spectra of the three structural color chiral photonic crystal pigments provided in Examples 1-2 were tested respectively. Figure 1 , 2 It can be seen that the emission wavelengths of the three dyes are aligned with the photonic bandgap of the chiral photonic crystal particles. The luminescent material in the R-chiral photonic crystal pigment corresponding to the chiral dopant R5011 can obtain a positive circularly polarized emission signal, representing left-handed circularly polarized emission; the S-chiral photonic crystal pigment corresponding to the chiral dopant S5011 can obtain a negative circularly polarized emission signal, representing right-handed circularly polarized emission.

[0055] Example 3

[0056] This embodiment provides two types of chiral photonic crystal color powders and their preparation methods. The chiral photonic crystal color powders include chiral photonic crystal microparticles and luminescent materials loaded on the chiral polymer film; the structural color is in the near-infrared range and is invisible to the naked eye.

[0057] The luminescent materials (with the maximum emission wavelength aligned with the photon bandgap center) are near-infrared quantum dots (silver-gold-selenium quantum dots, preparation method referred to J.Am.Chem.Soc.2021,143,2601-2607), with a maximum emission wavelength of 1000 nm and a half-width at half-maximum of 120 nm; and near-infrared quantum dots (silver-gold-selenium quantum dots, preparation method referred to J.Am.Chem.Soc.2021,143,2601-2607), with a maximum emission wavelength of 1250 nm and a half-width at half-maximum of 110 nm.

[0058] The raw materials for preparing the chiral photonic crystal pigment include the following components in parts by weight:

[0059] 100 parts of liquid crystal polymer monomer C6M, 7.8 parts of crosslinking agent TMPTA, 2.5 parts of photoinitiator I651, 0.8 or 1.3 parts of chiral dopant R5011, and 0.3 parts of luminescent material.

[0060] The chiral photonic crystal pigment has a photonic bandgap (structural color) with a bandgap center position of 1000 nm (corresponding to 1.3 parts of chiral dopant) and 1250 nm (corresponding to 0.8 parts of chiral dopant), and a bandgap width of 160 nm.

[0061] The preparation method of the chiral photonic crystal pigment is as follows:

[0062] The above-mentioned raw materials and dichloromethane (500 parts) were mixed evenly, and the mixture was heated to 80°C to volatilize the dichloromethane. The mixture was then poured into a polymerization template and irradiated with ultraviolet light at a wavelength of 365 nm for 20 minutes to obtain a chiral photonic crystal polymer film. The chiral photonic crystal polymer film was then pulverized in a cutting machine to obtain the chiral photonic crystal pigments, which were named R-near-infrared pigment 1 and R-near-infrared pigment 2, respectively.

[0063] Example 4

[0064] This embodiment provides two chiral photonic crystal pigments and their preparation methods. The only difference from Embodiment 3 is that the chiral dopant R5011 is replaced with an equal weight proportion of chiral dopant S5011, while other conditions are the same as in Embodiment 3. The products are named S-near-infrared pigment 1 and S-near-infrared pigment 2, respectively.

[0065] The chiral photonic crystal pigments provided in Examples 3-4 were subjected to emission spectra, transmittance spectra, and circularly polarized emission spectra tests, respectively. Figure 3 , 4It can be seen that the near-infrared emission wavelength is aligned with the photonic bandgap of the chiral photonic particles. The luminescent material in the R-chiral photonic crystal pigment corresponding to the chiral dopant R5011 can obtain a positive circularly polarized emission signal, representing left-handed circularly polarized emission; the S-chiral photonic crystal pigment corresponding to the chiral dopant S5011 can obtain a negative circularly polarized emission signal, representing right-handed circularly polarized emission.

[0066] Application Example 1

[0067] This application example provides an anti-counterfeiting method for chiral photonic crystal toners, the method being as follows:

[0068] Taking the three visible light structural colors and two near-infrared R-chiral photonic crystal color powders provided in Examples 1 and 3 as examples, R-blue color powder, R-green color powder and R-red color powder are filled into the first three "8"s of the pattern "8888", with R-blue color powder filling the first "8", R-green color powder filling the second "8", and R-red color powder filling the third "8"; R-near-infrared color powder 1 and R-near-infrared color powder 2 are mixed together and filled into the fourth "8".

[0069] Under naked-eye observation, the first "8" displays a blue structural color, the second "8" displays a green structural color, the third "8" displays a red structural color, and the fourth "8" has no color because the photonic bandgap is invisible to the naked eye in the near-infrared region. Figure 5 As shown.

[0070] Next, observing through a circular polarizer, under a left-handed circular polarizer corresponding solely to the blue light range, the first "8" color disappears while the second and third "8" colors remain unchanged; under a left-handed circular polarizer corresponding solely to the green light range, the second "8" color disappears while the first and third "8" colors remain unchanged; under a left-handed circular polarizer corresponding solely to the red light range, the third "8" color disappears while the first and second "8" colors remain unchanged; and under a left-handed circular polarizer in the visible light range, the structural colors of all three "8"s disappear, as shown below. Figure 5 As shown.

[0071] Illuminating the pattern "8888" with 365 nm ultraviolet light reveals luminescent patterns. The first "8" emits blue light, the second green, and the third red. The fourth "8" does not emit light because the near-infrared luminescent material is not excited. Under a right-handed circular polarizer corresponding to the blue light range, the brightness of the first "8" decreases, while the second and third "8"s remain unchanged. Under a right-handed circular polarizer corresponding to the green light range, the brightness of the second "8" decreases, while the first and third "8"s remain unchanged. Under a right-handed circular polarizer corresponding to the red light range, the brightness of the third "8" decreases, while the first and second "8"s remain unchanged. Under a right-handed circular polarizer in the visible light range, the brightness of all three "8" patterns decreases. Figure 6 As shown.

[0072] When the pattern "8888" is illuminated with 808 nm light, only the near-infrared luminescent material is excited. Since near-infrared luminescence is invisible to the naked eye, a near-infrared camera is used to observe the luminescent pattern. The luminescent pattern "8" at the fourth position, formed by the combined luminescence of R-near-infrared pigment 1 and R-near-infrared pigment 2, can be observed. A 1100 nm short-wavelength filter can filter out the luminescence of R-near-infrared pigment 2 while retaining the luminescence of R-near-infrared pigment 1. The luminescent pattern "6" belonging to R-near-infrared pigment 1 can then be seen. Figure 7 (See the image in the middle row). Under a right-handed circular polarizer in the corresponding near-infrared range, the luminescence intensity is significantly weakened. Figure 7 (Second row, middle image); using a 1100 nm long-wavelength filter can preserve the luminescence of R-near-infrared pigment 2, at which point the luminescent pattern "9" can be seen. Figure 7 (See right image). Under a right-handed circular polarizer in the corresponding near-infrared range, the luminescence intensity is significantly weakened. Figure 7 (Right image in the second row).

[0073] In summary, this invention, through the design and pulverization of chiral photonic crystal materials, yields a chiral photonic crystal pigment with chiral structural color and circularly polarized emission characteristics. This chiral photonic crystal pigment can be selected for both visible and near-infrared emission ranges, while also possessing both chiral structural color and circular polarization properties. Combining these emission ranges and characteristics significantly enhances the information anti-counterfeiting and encryption security of the chiral photonic crystal pigment in the anti-counterfeiting field.

[0074] The applicant declares that this invention illustrates the chiral photonic crystal pigments, their preparation method, and applications through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

[0075] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0076] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for preparing chiral photonic crystal pigments, characterized in that, The chiral photonic crystal pigment is composed of chiral photonic crystal microparticles and a luminescent material loaded on the chiral photonic crystal microparticles; The preparation method includes the following steps: A liquid crystal polymer monomer, a chiral dopant, and a luminescent material are mixed and polymerized to obtain a chiral photonic crystal polymer film loaded with the luminescent material, which is then pulverized to obtain the chiral photonic crystal color powder. The chiral photonic crystal particles have chiral structural colors, which are generated from the chiral photonic bandgap. The luminescent material is colorless or white when observed with the naked eye under visible light; the emission wavelength of the luminescent material is aligned with the center of the photonic bandgap of the chiral photonic crystal microparticles, and the half-width at half maximum (FWHM) of the emission wavelength of the luminescent material is smaller than the width of the photonic bandgap. The luminescent material, when loaded onto chiral photonic crystal microparticles, can produce circularly polarized luminescence. The liquid crystal polymer monomer comprises 80-120 parts by weight, the chiral dopant comprises 0.8-4 parts by weight, and the luminescent material comprises 0.1-1 parts by weight.

2. The preparation method according to claim 1, characterized in that, The liquid crystal polymer monomers include 1,4-bis[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene and / or 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene.

3. The preparation method according to claim 1, characterized in that, The chiral dopant includes any one or a combination of at least two of S5011, R5011, S811, or R811.

4. The preparation method according to claim 1, characterized in that, The mixing also includes mixing with crosslinking agents and photoinitiators.

5. The preparation method according to claim 4, characterized in that, The crosslinking agent comprises 4-8 parts by weight, and the photoinitiator comprises 1-3 parts by weight.

6. The preparation method according to claim 4, characterized in that, The crosslinking agent includes trimethylolpropane triacrylate and / or 2-methyl-1,4-benzobis(4-(((4-(acryloyloxy)butoxy)carbonyl)oxy)benzoate).

7. The preparation method according to claim 4, characterized in that, The photoinitiator includes 2,2-dimethoxy-2-phenylacetophenone and / or methyl benzoylformate.

8. The preparation method according to claim 1, characterized in that, The mixing also includes mixing with a solvent, and the mixing process further includes removing the solvent.

9. The preparation method according to claim 8, characterized in that, The solvent includes dichloromethane.

10. A chiral photonic crystal pigment prepared by the preparation method according to any one of claims 1-9.

11. The chiral photonic crystal pigment according to claim 10, characterized in that, The chiral photonic crystal pigment has chiral structural color and circularly polarized emission characteristics in the visible and / or near-infrared bands.

12. The application of a chiral photonic crystal toner according to claim 10 or 11 in anti-counterfeiting technology.

13. An anti-counterfeiting method, characterized in that, The anti-counterfeiting method includes the following steps: (1) Fill the chiral photonic crystal pigments of claim 10 or 11 to form an anti-counterfeiting pattern; (2) Observe the anti-counterfeiting pattern with the naked eye to obtain the first pattern, and then observe the first pattern through a circular polarizer whose application range covers the chiral structural color range of the chiral photonic crystal pigment, and observe the change of the first pattern. The luminescent material in the chiral photonic crystal pigment is excited to obtain a second pattern. The second pattern is then observed through a circular polarizer whose range encompasses the luminescence range of the luminescent material in the chiral photonic crystal pigment, and changes in the second pattern are observed.

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