Method for preparing information encryption device with independent regulation of visible light and infrared cross-band

Abstract

This application provides a method for fabricating an information encryption device that can be independently controlled across visible and infrared bands, relating to the fields of micro-nano optics, information security, and anti-counterfeiting technologies. The method includes: fabricating a coding layer on a target substrate; wherein the coding layer includes a first region without pattern coverage and a second region with pattern coverage; depositing a visible light control support layer on the target substrate and the coding layer; and depositing visible light control layers of different thicknesses on the visible light control support layer to obtain the information encryption device. The information encryption device includes: a target substrate, a coding layer, a visible light control support layer, and visible light control layers of different thicknesses; in the stacking direction of the multilayer structure, the stacked structure of the first region without pattern coverage in the coding layer includes: the target substrate, the visible light control support layer, and the visible light control layer; the stacked structure of the second region with pattern coverage in the coding layer includes: the target substrate, the coding layer, the visible light control support layer, and the visible light control layer.

Description

Technical Field

[0001] This application relates to the fields of micro-nano optics, information security and anti-counterfeiting technology, and more specifically, to a method for fabricating an information encryption device that can be independently controlled across visible light and infrared bands. Background Technology

[0002] With the rapid development of modern optical detection and information technology, the demand for information encryption, anti-counterfeiting authentication, and electromagnetic control is increasingly evolving towards multi-band and multi-dimensional directions. Information carriers are no longer limited to single visual perception but have expanded into the invisible light domain.

[0003] Traditional optical anti-counterfeiting labels typically only function in the visible light band, such as common holographic anti-counterfeiting labels and color-changing inks. Although these technologies are widely used, their optical characteristics exist only in a single wavelength, making them easy to copy and crack. Consequently, their security is no longer sufficient to meet the demands of high-end anti-counterfeiting and secure information transmission.

[0004] To improve information security, cross-band information encoding using invisible light bands (such as the infrared band) has become a highly promising solution. For example, designing a device that can display color patterns under the human eye and specific codes under an infrared thermal imager.

[0005] However, in existing multi-band compatible material designs, the optical response of a material is typically determined by both its geometry and material properties. A change in a single structure often affects the response across multiple bands simultaneously. When designers attempt to adjust the visible light color by altering the micro / nano structure of a material (such as the period, thickness, or unit cell size of a photonic crystal), they inevitably change its reflection or emission spectrum in the infrared band. Conversely, adjusting the structure to optimize infrared performance can also cause uncontrollable changes in the visible light color. This coupling effect severely limits the ability to independently edit multi-band information. Therefore, current solutions using invisible light bands are ineffective and costly to manufacture, failing to meet the needs of existing anti-counterfeiting applications. Summary of the Invention

[0006] In view of this, the purpose of this application is to provide a method for preparing an information encryption device that can be independently controlled across visible light and infrared bands, so as to improve the problem of poor optical encryption effect in the encryption devices in the prior art.

[0007] To address the aforementioned problems, in a first aspect, embodiments of this application provide a method for fabricating an information encryption device that can be independently controlled across visible and infrared bands, the method comprising: A coding layer is prepared on a target substrate; wherein the coding layer includes a first region without pattern coverage and a second region with pattern coverage; A visible light modulation support layer is deposited on the target substrate and the coding layer; The information encryption device is obtained by depositing visible light modulation layers of different thicknesses on the visible light modulation support layer.

[0008] In the above implementation process, a coding layer can be fabricated on the target substrate. To achieve encryption based on an image, the coding layer can include a first region without pattern coverage and a second region with pattern coverage. A corresponding visible light modulation support layer is then deposited on both the target substrate and the coding layer to provide different spectral modulation functions for the patterned coding layer, meeting the information security requirements of different wavelengths. To achieve different color presentations, visible light modulation layers of varying thicknesses can be deposited on the visible light modulation support layer. By adjusting the thickness of the visible light modulation layer and utilizing the thin-film interference effect, different reflection suppression peaks are generated in the visible light band, resulting in different colors and thus obtaining the corresponding information encryption device. Through the design of patterns, different wavelengths, and different colors, the encryption effect of the information encryption device in the invisible light band can be improved. The fabrication process can directly employ mature technologies, eliminating the need for expensive photolithography equipment. It is suitable for large-area, low-cost fabrication, meeting the usage requirements of various existing anti-counterfeiting application scenarios.

[0009] Optionally, the fabrication of the coding layer on the target substrate includes: Based on the application of the aforementioned information encryption device, the target substrate is determined; A first target material layer is obtained by depositing a first target material on the target substrate using a physical vapor deposition process. The first target material layer is graphically processed based on a preset encryption code to obtain the coded layer.

[0010] In the above implementation process, a target substrate of appropriate material can be determined according to the relevant requirements of the actual application of the information encryption device. Then, a first target material is deposited on the target substrate using physical vapor deposition (PVD) to obtain a first target material layer. To achieve a patterned encryption effect, an encryption code of appropriate shape can be preset according to the actual situation. Based on the encryption code, the first target material layer is patterned to obtain a corresponding encoding layer containing a first region without pattern coverage and a second region with pattern coverage. This allows for the selection of materials and encryption pattern shapes according to actual needs, meeting the encryption requirements of various application scenarios.

[0011] Optionally, the deposition rate of the first target material ranges from 1.0 Å / s to 4.0 Å / s, and the thickness of the first target material layer is from 100 nm to 200 nm.

[0012] In the above implementation process, the first target material used to prepare the coding layer can be deposited at a suitable deposition rate based on actual needs to reduce the unfavorable situation such as unevenness caused by material deposition that is too fast or too slow. In addition, the thickness of the first target material layer is 100nm to 200nm to reduce the unfavorable situation of not being able to perform effective pattern processing due to the material layer being too thin or too thick.

[0013] Optionally, the deposition of a visible light modulation support layer on the target substrate and the coding layer includes: The visible light modulation support layer is obtained by sequentially depositing multiple layers of materials on the target substrate and the coding layer using an electron beam thermal evaporation process. The multilayer material includes an inorganic non-metallic material with high transmittance in the infrared band.

[0014] In the above implementation process, a mature and low-cost process, electron beam thermal evaporation, can be used to sequentially deposit multiple layers of inorganic non-metallic materials with high infrared transmittance on the target substrate not covered by the coding layer and on the coding layer. This results in a visible light modulated support layer with high infrared transmittance characteristics, which can be obtained by modulating the spectrum to meet the encryption requirements of the infrared band. This increases the difficulty of copying and cracking the encrypted information in the information encryption device, improves the security of the information encryption device, and meets the needs of high-end anti-counterfeiting and secure information transmission in various scenarios.

[0015] Optionally, the inorganic non-metallic material includes: silicon dioxide, zinc sulfide, and germanium; The deposition rate of silicon dioxide ranges from 2.0 Å / s to 5.0 Å / s, and the thickness of the silicon dioxide layer ranges from 160 nm to 210 nm. The deposition rates of zinc sulfide range from 3.0 Å / s to 6.0 Å / s, and the thickness of the zinc sulfide layer ranges from 320 nm to 380 nm. The deposition rates of germanium range from 1.0 Å / s to 4.0 Å / s, and the thickness of the germanium layer ranges from 1100 nm to ~1300 nm.

[0016] In the above implementation process, inorganic non-metallic materials can include materials such as silicon dioxide, zinc sulfide, and germanium that can be spectrally modulated. Multilayer materials such as silicon dioxide, zinc sulfide, and germanium can be deposited at appropriate deposition rates based on actual needs to reduce unfavorable situations such as inhomogeneity caused by material deposition that is too fast or too slow. Furthermore, the thickness of multilayer materials such as silicon dioxide, zinc sulfide, and germanium can also be selected according to actual conditions to reduce unfavorable situations such as inability to effectively modulate the spectrum due to material layers that are too thin or too thick.

[0017] Optionally, the information encryption device is obtained by depositing visible light modulation layers of different thicknesses on the visible light modulation support layer, comprising: Based on the thin-film interference effect and the color requirements of the information encryption device, several different target thicknesses of the visible light modulation layer are determined. By using an electron beam thermal evaporation process and a pre-set mask, a second target material is deposited on the top surface of the visible light modulation support layer to obtain the information encryption device with a visible light modulation layer of different target thicknesses.

[0018] In the above implementation process, multiple target thicknesses of the visible light modulation layer can be determined based on the thin-film interference effect and the actual color requirements of the information encryption device, so as to present different colors based on multiple different target thicknesses. A mature and low-cost process, electron beam thermal evaporation, combined with a pre-set mask, can be used to deposit a second target material of inconsistent thickness on the top surface of the visible light modulation support layer, thereby obtaining information encryption devices with visible light modulation layers of different target thicknesses, enabling the construction of visible light patterns of different colors within the information encryption device.

[0019] Optionally, the deposition rate of the second target material includes 1.0 Å / s to 4.0 Å / s, and the target thickness is less than or equal to 200 nm.

[0020] In the above implementation process, the second target material used to present the visible light pattern can be deposited at an appropriate deposition rate based on actual needs to reduce unfavorable situations such as unevenness caused by material deposition that is too fast or too slow. In addition, the thickness of the second target material layer is less than or equal to 200 nm to reduce the unfavorable situation of unclear color caused by excessively thick material layers.

[0021] Optionally, the background vacuum level of the electron beam thermal evaporation process is less than or equal to 10. -3 Pa.

[0022] In the above implementation process, the background vacuum level of the electron beam thermal evaporation process is less than or equal to 10. -3 Pa, to optimize the effect of electron beam thermal evaporation process through higher vacuum.

[0023] Optionally, the material deposition temperature is t, where 15℃≤t≤80℃.

[0024] In the above implementation process, considering the thermal stability of the substrate material, the temperature during material deposition is controlled between 15°C and 80°C to reduce the adverse effects of excessively low or high temperatures on material deposition.

[0025] Secondly, embodiments of this application also provide an information encryption device that can be independently modulated across visible light and infrared bands. The information encryption device is prepared by the method described in any of the above-mentioned methods. The information encryption device includes: a target substrate, an encoding layer, a visible light modulation support layer, and visible light modulation layers of different thicknesses. In the stacking direction of the multilayer structure, the stacked structure of the first region without pattern coverage in the coding layer includes: the target substrate, the visible light modulation support layer, and the visible light modulation layer; The stacked structure of the second region covered by the pattern in the coding layer includes: the target substrate, the coding layer, the visible light modulation support layer, and the visible light modulation layer.

[0026] In the above implementation process, the information encryption device prepared includes two parts: a stacked structure corresponding to the first region of the coding layer without pattern coverage, and a stacked structure corresponding to the second region of the coding layer with pattern coverage. The difference between the two stacked structures forms the corresponding encryption pattern. The spectrum is adjusted accordingly by the visible light modulation support layer, and different colors of encryption patterns are achieved by visible light modulation layers of different thicknesses.

[0027] In summary, the embodiments of this application provide a method for fabricating an information encryption device that can be independently controlled across visible and infrared bands. By designing patterns, different bands, and different colors, the encryption effect of the information encryption device in the invisible light band can be improved. The fabrication process can be carried out directly using mature technology without the need for expensive photolithography equipment. It is suitable for large-area, low-cost fabrication and meets the usage requirements of various existing anti-counterfeiting application scenarios. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic flowchart illustrating a method for fabricating an information encryption device that can be independently controlled across visible and infrared bands, as provided in an embodiment of this application; Figure 2 A detailed flowchart of step S100 provided for an embodiment of this application; Figure 3 A detailed flowchart of step S300 provided for an embodiment of this application; Figure 4A schematic diagram of the structure of an information encryption device that can be independently controlled across visible light and infrared bands, provided in an embodiment of this application; Figure 5 A schematic diagram illustrating the effect of visible light modulation layers of different thicknesses on visible light performance, as provided in an embodiment of this application. Figure 6 A schematic diagram showing the spectral characteristics of two photonic crystals provided in the embodiments of this application in the 8-14µm atmospheric window band; Figure 7 A schematic diagram of parameters of a first photonic crystal provided for an embodiment of this application; Figure 8 This is a schematic diagram of visible light and infrared modulation provided in an embodiment of this application.

[0030] Icons: 410 - Target substrate; 420 - Encoding layer; 430 - Visible light modulation support layer; 440 - Visible light modulation layer; S1 - First region; S2 - Second region; F1 - Overlay direction. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.

[0032] In existing multi-band compatible material design, the optical response of a material is typically determined by its geometry and material properties; a change in a single structure often affects the response across multiple bands simultaneously. When designers attempt to adjust the visible light color by altering the micro / nano structure of a material (such as the period, thickness, or unit cell size of a photonic crystal), they inevitably change its reflection or emission spectrum in the infrared band. Conversely, adjusting the structure to optimize infrared performance can also cause uncontrollable changes in the visible light color. This coupling effect severely limits the ability to independently edit multi-band information. Therefore, current solutions using invisible light bands are ineffective and costly to manufacture, failing to meet the needs of existing anti-counterfeiting applications.

[0033] To address the aforementioned issues, this application provides a method for fabricating an information encryption device that can be independently controlled across visible and infrared bands. This method can improve the encryption effect of the information encryption device in the invisible light band by designing patterns, different bands, and different colors. The fabrication process can directly utilize mature technologies without the need for expensive photolithography equipment, making it suitable for large-area, low-cost fabrication and meeting the usage requirements of various existing anti-counterfeiting application scenarios.

[0034] Please see Figure 1 , Figure 1 This is a flowchart illustrating a method for fabricating an information encryption device that can be independently controlled across visible and infrared bands, as provided in an embodiment of this application. The method may include steps S100-S300.

[0035] Step S100: Prepare the coding layer on the target substrate.

[0036] Specifically, an encoding layer can be prepared on the target substrate, and in order to achieve encryption based on the image, the encoding layer may include a first region without pattern coverage and a second region with pattern coverage.

[0037] Optionally, the second region can be a relevant region of the material with a coding layer on the target substrate, and the first region can be a relevant region with a hollowed-out coding layer, so that a corresponding coding layer with a cryptographic pattern shape can be formed by combining the first region and the second region.

[0038] Step S200: Deposit a visible light modulation support layer on the target substrate and the coding layer.

[0039] Among them, corresponding visible light modulation support layers can be deposited on the target substrate and the coding layer to provide different spectral modulation functions for the patterned coding layer and meet the information security requirements of different bands.

[0040] Optionally, the visible light modulation support layer can adjust the spectrum of the coding layer based on its own optical properties so that the optical features of the coding layer are in different bands, thereby reducing the disadvantage of easy copying and cracking caused by encryption in a single band.

[0041] In step S300, visible light modulation layers of different thicknesses are deposited on the visible light modulation support layer to obtain the information encryption device.

[0042] In order to achieve different color presentations, visible light control layers of different thicknesses can be deposited on the visible light control support layer. By adjusting the thickness of the visible light control layer, different reflection suppression peaks can be generated in the visible light band using the thin film interference effect, thereby presenting different colors and obtaining the corresponding information encryption device.

[0043] exist Figure 1 In the illustrated embodiments, the encryption effect of information encryption devices in the invisible light band can be improved by designing patterns, different wavelengths, and different colors. The fabrication process can be carried out directly using mature technology, without the need for expensive photolithography equipment. It is suitable for large-area, low-cost fabrication and meets the usage needs of various existing anti-counterfeiting application scenarios.

[0044] Optionally, please refer to Figure 2 , Figure 2 The following is a detailed flowchart of step S100 provided in an embodiment of this application. Step S100 may include steps S110-S130.

[0045] Step S110: Determine the target substrate based on the application of the information encryption device.

[0046] Among these, the target substrate of the corresponding material can be determined according to the relevant requirements of the actual application of information encryption devices.

[0047] Optionally, a target substrate of appropriate material and size can be selected based on the application requirements of the information encryption device. For example, an optical-grade polyethylene terephthalate (PET) film with a thickness of 50µm can be used as the target substrate. PET material is not only flexible but also highly transparent in the visible light band and has an extremely high absorption rate (approximately 0.92) in the infrared band within the 8-14µm atmospheric window. After determining the target substrate, it can be cleaned. The cleaning process may include: ultrasonic cleaning in anhydrous ethanol and deionized water for 10 minutes sequentially, drying with nitrogen, and then performing glow discharge treatment in a vacuum chamber to remove organic contaminants from the surface of the target substrate and increase the adhesion of the film layer.

[0048] Step S120: Deposit the first target material on the target substrate using a physical vapor deposition process to obtain the first target material layer.

[0049] Among them, the corresponding first target material can be deposited on the target substrate through physical vapor deposition process to obtain the corresponding first target material layer.

[0050] Alternatively, physical vapor deposition processes may include electron beam thermal evaporation, magnetron sputtering, or thermal evaporation processes, whereby the prepared target substrate can be loaded into an electron beam thermal evaporation coating machine (E-beam Evaporator) for material deposition coating.

[0051] Optionally, the first target material may include metallic materials such as copper.

[0052] It should be noted that the deposition rate of the first target material can range from 1.0 Å / s to 4.0 Å / s, and the thickness of the first target material layer can range from 100 nm to 200 nm. The first target material used to prepare the coding layer can be deposited at a suitable deposition rate based on actual needs to reduce undesirable situations such as inhomogeneity caused by material deposition being too fast or too slow. Furthermore, the thickness of the first target material layer is 100 nm to 200 nm to reduce the undesirable situation of being unable to perform effective patterning due to the material layer being too thin or too thick.

[0053] For example, the electron gun can be activated to deposit a 100 nm thick Cu layer on the target substrate at a deposition rate of 3.0 Å / s. During the deposition process, the support frame carrying the target substrate can rotate at a constant speed to ensure uniformity, and the temperature of the target substrate can be controlled below 80°C by a water cooling system to prevent the target substrate from shrinking due to heat.

[0054] Step S130: Based on the preset encryption code, the first target material layer is graphically processed to obtain the coded layer.

[0055] In order to achieve a patterned encryption effect, an encryption code of the corresponding shape can be preset in advance according to the actual situation. Based on the encryption code, the first target material layer is patterned to obtain a corresponding coded layer containing a first area without pattern coverage and a second area with pattern coverage.

[0056] Alternatively, patterning can include operations such as laser direct writing, photolithography, or electron beam exposure.

[0057] Optionally, laser engraving can be performed on the first target material layer to process metal patterns with different duty cycles. The area covered by the metal pattern on the target substrate is defined as the second region, and the area not covered by the metal pattern is defined as the first region. That is, the area where the copper metal is removed and the PET substrate is exposed is defined as the first region, and the area where the copper metal pattern is retained is defined as the second region.

[0058] For example, a pulsed laser can be used for precision laser etching. Based on a preset encryption code corresponding to a pattern (such as a square ring, St. Andrew's cross, or a square), the Cu layer in a specific area is completely removed to form a first region and a second region.

[0059] exist Figure 2 In the embodiments shown, materials and encryption pattern shapes can be selected according to actual needs to meet encryption requirements in various application scenarios.

[0060] Optionally, step S200 may include: sequentially depositing multiple layers of material on the target substrate and the coding layer using an electron beam thermal evaporation process to obtain a visible light modulated support layer. This mature and low-cost process allows for the sequential deposition of multiple layers of inorganic non-metallic materials with high infrared transmittance on both the target substrate not covered by the coding layer and the coding layer. This results in a visible light modulated support layer with high infrared transmittance, allowing for spectral modulation to meet encryption requirements in different wavelengths. This increases the difficulty of copying and cracking encrypted information in the information encryption device, improves its security, and meets the needs of high-end anti-counterfeiting and secure information transmission in various scenarios.

[0061] The multilayer material may include: an inorganic non-metallic material with high transmittance in the infrared band, to form a multilayer dielectric film based on the multilayer material.

[0062] Alternatively, the sample with the coding layer can be reinserted into the coating machine to deposit multiple layers of dielectric film sequentially.

[0063] It should be noted that inorganic non-metallic materials may include dielectric materials such as silicon dioxide, zinc sulfide, and germanium.

[0064] The deposition rates for silicon dioxide range from 2.0 Å / s to 5.0 Å / s, with silicon dioxide layer thicknesses ranging from 160 nm to 210 nm. For zinc sulfide, the deposition rates range from 3.0 Å / s to 6.0 Å / s, with zinc sulfide layer thicknesses ranging from 320 nm to 380 nm. For germanium, the deposition rates range from 1.0 Å / s to 4.0 Å / s, with germanium layer thicknesses ranging from 1100 nm to ~1300 nm. Multilayer materials such as silicon dioxide, zinc sulfide, and germanium can be deposited at appropriate rates based on actual needs to reduce inhomogeneities caused by excessively fast or slow deposition. Furthermore, the thickness of these multilayer materials can also be selected appropriately to minimize the inability to effectively control the spectrum due to excessively thin or thick layers.

[0065] For example, a silicon dioxide (SiO2) layer can be deposited first as a low-refractive-index matching layer, with the deposition rate controlled at 3.0 Å / s, the electron gun beam current at 40-60 mA, and the physical thickness at 189 nm. Next, a zinc sulfide (ZnS) layer is deposited. Because ZnS is prone to sublimation, the electron beam current must be strictly controlled between 20-30 mA, the deposition rate at approximately 4.0 Å / s, and the physical thickness at 356 nm. Subsequently, a germanium (Ge) layer is deposited. Ge, as a high-refractive-index material, works in conjunction with the low-refractive-index material to form the optical cavity. The deposition rate is controlled at 3.0 Å / s, the beam current at 80-100 mA, and the physical thickness at 1215 nm.

[0066] Optionally, please refer to Figure 3 , Figure 3 This is a detailed flowchart of step S300 provided in an embodiment of the present application. Step S300 may include steps S310-S320.

[0067] Step S310: Based on the thin-film interference effect and the color requirements of the information encryption device, determine several different target thicknesses of the visible light modulation layer.

[0068] Among them, multiple different target thicknesses of the visible light control layer can be determined based on the thin film interference effect and the actual color requirements of the information encryption device, so as to present different colors based on multiple different target thicknesses.

[0069] In step S320, a second target material is deposited on the top surface of the visible light modulation support layer using an electron beam thermal evaporation process combined with a preset mask, thereby obtaining an information encryption device with a visible light modulation layer of different target thicknesses.

[0070] Among them, a mature and low-cost process called electron beam thermal evaporation can be used in combination with a pre-set mask to deposit a second target material of inconsistent thickness on the top surface of the visible light modulation support layer, thereby obtaining an information encryption device with visible light modulation layers of different target thicknesses, and enabling the construction of visible light patterns of different colors in the information encryption device.

[0071] Optionally, the second target material can be tantalum pentoxide (Ta2O5). By adjusting the thickness of the tantalum pentoxide layer, different reflection suppression peaks are generated in the visible light band using the thin film interference effect, thereby presenting different colors.

[0072] It should be noted that the deposition rate of the second target material can range from 1.0 Å / s to 4.0 Å / s, and the target thickness is less than or equal to 200 nm. The second target material used to present the visible light pattern can be deposited at an appropriate deposition rate based on actual needs to reduce undesirable conditions such as inhomogeneity caused by material deposition being too fast or too slow. Furthermore, the thickness of the second target material layer is less than or equal to 200 nm to reduce the undesirable condition of unclear colors caused by an excessively thick material layer.

[0073] Optionally, a mechanical mask can be used to block different areas, allowing for the staged deposition of tantalum pentoxide layers on the Ge layer surface of the visible light modulation support layer. For example, no Ta₂O₅ is deposited in the first area (0 nm thick); using mask 1, a 100 nm thick Ta₂O₅ layer is deposited in the second area; and using mask 2, a 200 nm thick Ta₂O₅ layer is deposited in the third area. The Ta₂O₅ deposition rate is controlled at 2 Å / s. In this way, visible light patterns of different colors are constructed on the sample surface.

[0074] It should be noted that the background vacuum level of the electron beam thermal evaporation process is less than or equal to 10. -3 Pa, to optimize the effect of electron beam thermal evaporation process through higher vacuum.

[0075] It should be noted that, considering the thermal stability of the substrate material, the material deposition temperature is t, 15℃≤t≤80℃, in order to reduce the adverse effects of excessively low or high temperatures on material deposition, such as shrinkage and deformation of the target substrate due to excessively high temperatures, and uneven deposition due to excessively low temperatures.

[0076] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of an information encryption device that can be independently controlled across visible light and infrared bands, provided in an embodiment of this application. The information encryption device is prepared by the method in any of the above embodiments. The information encryption device includes: a target substrate 410, an encoding layer 420, a visible light control support layer 430, and visible light control layers 440 of different thicknesses. In the stacking direction F1 of the multilayer structure, the stacked structure of the first region S1 without pattern coverage in the coding layer 420 includes: target substrate 410, visible light modulation support layer 430 and visible light modulation layer 440. The stacked structure of the second region S2 covered by the pattern in the coding layer 420 includes: target substrate 410, coding layer 420, visible light modulation support layer 430 and visible light modulation layer 440.

[0077] It should be noted that, in the stacking direction F1, the stacked structure of the first region S1 without pattern coverage forms the first photonic crystal, and the stacked structure of the second region S2 with pattern coverage in the coding layer 420 forms the second photonic crystal.

[0078] For example, the stacked structure of the first region S1 without pattern coverage in the coding layer 420, from bottom to top, can be: PET substrate / SiO2 layer (189nm) / ZnS layer (356nm) / Ge layer (1215nm) / Ta2O5 layer (0-200nm). In the structure of the first photonic crystal, the visible light color is jointly regulated by Ta2O5 and Ge. The Ge layer blocks transmission due to its high extinction coefficient in the visible light band and works with the Ta2O5 layer to produce structural color. It exhibits a transmittance of approximately 0.56 and an absorptivity of 0.14 in the 8-14µm band. Most of the infrared radiation is transmitted and absorbed by the bottom PET substrate, achieving high emissivity.

[0079] For example, the stacked structure of the second region S2 covered by the pattern in the coding layer 420 can be, from bottom to top, as follows: PET substrate / Cu layer (100nm) / SiO2 layer (189nm) / ZnS layer (356nm) / Ge layer (1215nm) / Ta2O5 layer (0-200nm). In the structure of the second photonic crystal, the visible light color modulation mechanism is completely consistent with that of the first photonic crystal. In the 8-14 µm band, the Cu layer acts as an infrared-opaque metal mirror, effectively blocking the transmission of light waves to the PET substrate, and works synergistically with the overlying photonic crystal film to achieve low emissivity.

[0080] Optionally, please refer to Figure 5 , Figure 5 This is a schematic diagram illustrating the control effect of visible light performance by visible light modulation layers 440 of different thicknesses provided in this application embodiment. The color of visible light is mainly determined by the thin film interference effect formed by the top Ta2O5 layer and the Ge layer below. Figure 5 Figure (a) shows the reflectance spectrum curves. When the thickness of Ta2O5 increases from 0 nm to 200 nm, the suppression peak in the reflectance spectrum shifts significantly in the visible light range of 380 nm to 780 nm due to the change in optical path. Figure 5 (b) shows the corresponding CIE-1931 chromaticity diagram. As the thickness changes, the sample's colors are widely distributed across the chromaticity diagram, encompassing blue, green, yellow, and other hues. This means that by simply changing the thickness of the top layer of Ta₂O₅, any customizable visible light pattern can be achieved.

[0081] Optionally, please refer to Figure 6 , Figure 6 This is a schematic diagram illustrating the spectral characteristics of two photonic crystals provided in the embodiments of this application within the 8-14µm atmospheric window band. Figure 6 Image (a) is a schematic diagram of the first photonic crystal (PC1). Figure 6(b) is a schematic diagram of the second photonic crystal (PC2). For the second photonic crystal, due to the introduction of a 100 nm thick Cu layer at the bottom, its optical response is no longer affected by the PET substrate and exhibits extremely high reflectivity in synergy with the upper thin film structure. The spectral curve shows that the average reflectivity of PC2 is approximately 0.93. According to Kirchhoff's law, for opaque objects, emissivity E = 1 - R (reflectivity). Therefore, the infrared emissivity of the second photonic crystal is extremely low, approximately 0.07. Under infrared thermal imaging, this region radiates very little energy, appearing as low temperature (dark). For the first photonic crystal, Figure 3 The spectral curves show that it has high transmittance in the 8-14µm band, with an average transmittance of about 0.56, while it has a certain absorptivity of about 0.14.

[0082] To explain the high emission characteristics of PC1, please refer to [link / reference]. Figure 7 , Figure 7 This is a schematic diagram of parameters for a first photonic crystal provided in an embodiment of this application, characterizing the relationship between the reflectivity, absorptivity, and transmittance of the photonic crystal film and the absorptivity of the PET substrate when Ta2O5 is 100 nm. Figure 7 As shown, infrared radiation (transmittance approximately 0.56) passing through the first photonic crystal film layer directly incident on the underlying PET substrate. The PET substrate exhibits extremely strong molecular vibrational absorption (CO and CH bond vibrations) in the 8-14µm wavelength range. Figure 4 The absorptivity curve of PET shows an average absorptivity of approximately 0.92. According to the laws of energy conservation and radiative transfer, the effective emissivity of the PC1 structure is the sum of the film's own emission and the substrate's transmitted emission. The theoretical calculation formula is: Effective emissivity ≈ Structural absorptivity + (Structural transmittance × Substrate absorptivity). Substituting the data, we get: 0.14 + (0.56 × 0.92) ≈ 0.65. Therefore, PC1 exhibits a relatively high emissivity (0.65), appearing as high temperature (bright color) under infrared thermal imaging.

[0083] Therefore, by the presence or absence of patterns in the bottom coding layer 420 and their synergistic effect with the upper photonic crystal structure or the lower target substrate 410, this application achieves a significant difference in emissivity in the infrared band, thereby enabling the generation of clear, high-contrast images in an infrared camera.

[0084] Optionally, please refer to Figure 8 , Figure 8This diagram illustrates visible light and infrared modulation as provided in an embodiment of this application, verifying the independence of visible light and infrared modulation. In the experiment, Ta₂O₅ films with thicknesses of 95 nm, 115 nm, and 135 nm were deposited on top of PC1 and PC2, respectively. Infrared spectral data showed that although the visible light color changed drastically, the average emissivity values ​​of PC1 and PC2 fluctuated very little in the 8-14 µm range (variation <0.06). This is because the thickness variation scale of the top Ta₂O₅ layer (nanometer scale) is much smaller than the infrared wavelength (micrometer scale), and its impact on the optical path length in the infrared band is negligible. This demonstrates that the visible light modulation layer 440 is almost "transparent" to infrared performance, achieving true independent decoupling. Figure 8 This visually demonstrates the decoupling effect. Figure 8 The middle image (a) is a visible light photograph. The colored logo pattern is constructed from Ta2O5 thin film structures of different thicknesses (95nm, 115nm and 135nm). Figure 8 Image (b) shows an infrared thermal image of the same location. The infrared image clearly shows the letter pattern "IOE". This letter pattern is entirely determined by the distribution of the underlying copper layer, while the logo pattern under visible light completely disappears in the infrared field of view. This demonstrates that this application can achieve spectral decoupling between the visible light and infrared bands. By simultaneously loading visible light color patterns and infrared thermal radiation characteristics onto a single structural surface, two independent information channels that do not interfere with each other are established. This orthogonal information loading strategy significantly improves the concealment and security of data transmission, greatly enhancing the concealment and security of information.

[0085] Based on the above characteristics, the information encryption device prepared in this application can be widely used in advanced anti-counterfeiting fields. For example, on product packaging or certificates, it displays a brand logo or portrait under natural light, while displaying an encrypted verification code or anti-counterfeiting dot matrix under dedicated infrared equipment, making it difficult for counterfeiters to simultaneously replicate dual-band features. Furthermore, this device also has significant value in the field of electromagnetic control. This structure can simulate environmental background colors (such as jungle camouflage) in the visible light band, while simultaneously reconstructing specific thermal textures or matching them with background thermal radiation in the infrared band, achieving all-weather electromagnetic control. Moreover, by adjusting the duty cycle of the metal pattern, fine-tuning of multi-level reflectivity in the infrared band can be achieved, thereby constructing an infrared camouflage effect. It can also be applied to the field of optical communication, using the visible light layer to display conventional markings and the infrared layer to transmit concealed modulation signals.

[0086] In summary, this application provides a method for fabricating an information encryption device with independent cross-band control of visible and infrared light, achieving a decoupled design. The visible light color depends only on the thickness of the top visible light control layer, and this thickness variation (0-200 nm) is negligible compared to the infrared wavelength (8-14 µm), having a negligible impact on infrared performance. The infrared image depends only on the emissivity of the photonic crystal formed by the stacked structure of the first and second regions, and is independent of the visible light color. High-contrast infrared imaging is also achieved. Utilizing the high absorption (i.e., high emission) characteristics of the target substrate in the 8-14 µm band, combined with the fact that the photonic crystal in the first region has an absorption rate of approximately 0.14 and a transmittance of approximately 0.56 in the 8-14 µm band, exhibiting a high emissivity (approximately 0.65), while the photonic crystal in the second region exhibits extremely low emissivity (approximately 0.07) due to the blocking effect of the underlying coding layer, the difference between the two is significant. The fabricated information encryption device exhibits rich color performance. By adjusting the thickness of the visible light modulation layer, multiple color outputs can be achieved in the CIE-1931 chromaticity diagram, meeting the encoding requirements of complex color patterns. Furthermore, it offers good process compatibility. Employing mature processes such as electron beam thermal evaporation and laser engraving, it eliminates the need for expensive photolithography equipment, making it suitable for large-area, low-cost fabrication.

[0087] In the several embodiments provided in this application, it should be understood that the disclosed device can also be implemented in other ways. The device embodiments described above are merely illustrative; for example, the block diagrams in the accompanying drawings illustrate the possible architecture, functions, and operations of the device according to various embodiments of this application. In this regard, each block in the block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram, and combinations of block diagrams, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0088] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0089] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0090] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0091] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

[0092] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A method for fabricating an information encryption device that can be independently controlled across visible and infrared bands, characterized in that, The method includes: A coding layer is prepared on a target substrate; wherein the coding layer includes a first region without pattern coverage and a second region with pattern coverage; A visible light modulation support layer is deposited on the target substrate and the coding layer; The information encryption device is obtained by depositing visible light modulation layers of different thicknesses on the visible light modulation support layer.

2. The method according to claim 1, characterized in that, The fabrication of the coding layer on the target substrate includes: Based on the application of the aforementioned information encryption device, the target substrate is determined; A first target material layer is obtained by depositing a first target material on the target substrate using a physical vapor deposition process. The first target material layer is graphically processed based on a preset encryption code to obtain the coded layer.

3. The method according to claim 2, characterized in that, in, The deposition rate of the first target material ranges from 1.0 Å / s to 4.0 Å / s, and the thickness of the first target material layer ranges from 100 nm to 200 nm.

4. The method according to claim 1, characterized in that, The deposition of a visible light modulation support layer on the target substrate and the coding layer includes: The visible light modulation support layer is obtained by sequentially depositing multiple layers of materials on the target substrate and the coding layer using an electron beam thermal evaporation process. The multilayer material includes an inorganic non-metallic material with high transmittance in the infrared band.

5. The method according to claim 4, characterized in that, in, The inorganic non-metallic materials include: silicon dioxide, zinc sulfide, and germanium; The deposition rate of silicon dioxide ranges from 2.0 Å / s to 5.0 Å / s, and the thickness of the silicon dioxide layer ranges from 160 nm to 210 nm. The deposition rates of zinc sulfide range from 3.0 Å / s to 6.0 Å / s, and the thickness of the zinc sulfide layer ranges from 320 nm to 380 nm. The deposition rates of germanium range from 1.0 Å / s to 4.0 Å / s, and the thickness of the germanium layer ranges from 1100 nm to ~1300 nm.

6. The method according to claim 1, characterized in that, The information encryption device is obtained by depositing visible light modulation layers of different thicknesses on the visible light modulation support layer, comprising: Based on the thin-film interference effect and the color requirements of the information encryption device, several different target thicknesses of the visible light modulation layer are determined. By using an electron beam thermal evaporation process and a pre-set mask, a second target material is deposited on the top surface of the visible light modulation support layer to obtain the information encryption device with a visible light modulation layer of different target thicknesses.

7. The method according to claim 6, characterized in that, in, The deposition rate of the second target material ranges from 1.0 Å / s to 4.0 Å / s, and the target thickness is less than or equal to 200 nm.

8. The method according to claim 4 or 6, characterized in that, in, The background vacuum level of the electron beam thermal evaporation process is less than or equal to 10. -3 Pa.

9. The method according to any one of claims 2-7, characterized in that, in, The material deposition temperature is t, where 15℃≤t≤80℃.

10. An information encryption device that allows for independent modulation of visible light and infrared wavelengths, characterized in that, The information encryption device is prepared by the method of any one of claims 1-9, and the information encryption device comprises: a target substrate, an encoding layer, a visible light modulation support layer, and visible light modulation layers of different thicknesses; In the stacking direction of the multilayer structure, the stacked structure of the first region without pattern coverage in the coding layer includes: the target substrate, the visible light modulation support layer, and the visible light modulation layer; The stacked structure of the second region covered by the pattern in the coding layer includes: the target substrate, the coding layer, the visible light modulation support layer, and the visible light modulation layer.

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