Photoelectric information leakage protection film and preparation method thereof

Abstract

The present invention discloses a photoelectric information leakage protection film and a preparation method thereof, comprising a base layer and a protective layer cured on top of the base layer. The protective layer has a thickness of 1-100 μm and is formed by mixing nanosilver wires and indium tin oxide / cesium tungsten bronze / arsenic trioxide, and then being coupled to the upper surface of the base layer by a one-step coating method. The plurality of nanosilver wires are overlapped and stacked to form an irregular conductive grid. The weight ratio of the nanosilver wires to indium tin oxide / cesium tungsten bronze / arsenic trioxide is between 1:9 and 9:1. The protective layer can reflect electromagnetic signals, preventing electromagnetic radiation signals from passing through the protective layer and generating electromagnetic leakage from the incident direction, while also preventing incident infrared lasers from forming infrared outgoing light from the incident direction.

Description

Technical Field

[0001] The present invention relates to the field of information security protection, and in particular to a photoelectric information leakage protection film and a preparation method thereof. Background Art

[0002] Driven by computer and Internet technologies, information tools such as office automation, paperless office, e-government, and e-commerce have developed rapidly. Computers have been widely used in various fields of social life. Among them, electromagnetic radiation is one of the main ways for computers and their network systems to leak information. How to prevent information leakage and ensure information security has become an urgent problem that needs to be solved.

[0003] With the development of laser technology, diffuse laser voice acquisition technology has attracted increasing attention due to its advantages of non-invasive and low-risk voice information acquisition. However, relatively few protective measures are available. With the application of optoelectronic technologies in voice information acquisition, such as diffuse laser eavesdropping, which offers advantages such as non-contact, high concealment, and high sensitivity, the targets of information theft have shifted from glass to a variety of materials. Eavesdropping systems, which can eavesdrop on indoor objects (pictures, cups, cigarette cases, etc.) through glass, have become a major eavesdropping method, significantly challenging traditional voice information leakage protection systems that place vibration jammers on window glass to generate additional vibration noise to obliterate useful information.

[0004] In order to effectively prevent the leakage of photoelectric information, there are also various protection methods in the existing technology:

[0005] CN202120871876.9 discloses a metal coating shielding method, which coats a metal conductive layer on a thin film for electromagnetic shielding. However, the metal coating increases the light reflectivity of the film, thereby increasing the risk of information leakage due to infrared lasers. CN201920263546.4 discloses a method for blocking infrared lasers, but this method only considers the blocking factor and has no effect on electromagnetic shielding. The above methods only meet some of the functions and cannot fully meet the requirements for optical and electromagnetic information leakage.

[0006] Multi-layer protection methods are also disclosed in the prior art, such as the protective film for preventing infrared laser information leakage and electromagnetic information leakage of ZL202110899153.4. Its technical solution is to sequentially form an electromagnetic shielding layer, a thermal sensitive layer, an infrared absorption layer and a photoluminescent layer according to the protection requirements, wherein the electromagnetic shielding is attached to the substrate by sputtering coating, and each layer realizes its own function by superposition. Therefore, there are many layers, and each layer has a loss to visible light. Therefore, the film produced by this method has low visible light transmittance, and its production process is complicated and the production cost is high.

[0007] The protective film for preventing photoelectric information leakage of CN202111586781.3 is superior to ZL202110899153.4 in terms of infrared protection wavelength range, effect and electromagnetic shielding range, but it adopts a multi-layer coating method, which also has disadvantages such as complex production process and high production cost.

[0008] Therefore, a protective film for preventing photoelectric information leakage is needed, which has a simple preparation process and can realize thin-film electromagnetic shielding and infrared absorption functions. Summary of the Invention

[0009] The purpose of the present invention is to provide a photoelectric information leakage protection film and a preparation method thereof. The protective film has a simple structure, and the protective layer is formed on the base layer in one step after mixing nano silver wires and indium tin oxide / cesium tungsten bronze / arsenic trioxide. The electromagnetic shielding and infrared absorption functions of the film can be achieved through a simple method.

[0010] The first aspect of the present invention relates to a photoelectric information leakage protection film, comprising a base layer and a protective layer solidified on top of the base layer, wherein the base layer is used to provide support for the protective film, and the protective layer has a thickness of 1-100 μm. The protective layer is formed by mixing nanosilver wires and indium tin oxide / cesium tungsten bronze / arsenic trioxide and then coupling it to the upper surface of the base layer by coating in one step; wherein, multiple nanosilver wires are overlapped and stacked to form an irregular conductive grid; the weight ratio of the nanosilver wires to indium tin oxide / cesium tungsten bronze / arsenic trioxide is between 1:9 and 9:1; the protective layer can reflect electromagnetic signals, prevent electromagnetic radiation signals from passing through the protective layer to generate electromagnetic leakage from the incident direction, and at the same time prevent the incident infrared laser from forming infrared output light from the incident direction.

[0011] Furthermore, the photoelectric information leakage protection film is provided with the base layer, the protection layer, the adhesive layer and the protective layer in order from bottom to top, the adhesive layer is adhered to the top of the protective layer, and the protective layer is adhered to the top of the adhesive layer;

[0012] The base layer and the protective layer are transparent films, the materials of the base layer and the protective layer are selected from polyethylene terephthalate (PET), polyvinyl butyral (PVB) or ethylene-vinyl acetate copolymer (EVA), and the thickness of the base layer is 5-100 μm;

[0013] The adhesive layer is an acrylic adhesive, which is coated on the top of the protective layer and is used to adhere the protective layer and the protective layer. The thickness of the adhesive layer is 10-50 μm;

[0014] The thickness of the protective layer is 1-100 μm, and is used to protect the protective layer from damage before mounting, while ensuring that the adhesive layer is not contaminated.

[0015] Furthermore, the transmittance of the protective film at a wavelength of 900nm-1800nm ​​is less than 0.1%, and the shielding effectiveness at 30MHz-18GHz is more than 30db.

[0016] The second aspect of the present invention relates to a method for preparing the photoelectric information leakage protection film, comprising: uniformly mixing nano silver wires and indium tin oxide / cesium tungsten bronze / arsenic trioxide in a weight ratio of 1:9 to 9:1 and placing the mixture in acetone, using ultrasonic stirring to form a suspension, and coating the suspension on the surface of a prefabricated PET material base layer 1 through a coating process; drying at 150°C-185°C for 3-5 hours and then naturally cooling to form a precipitated protective layer 2.

[0017] Furthermore, the method for preparing the photoelectric information leakage protection film includes installing the base layer or the protective layer of the photoelectric information leakage protection film on the device to be protected.

[0018] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0019] The protective layer of the protective film of the present invention is prepared by coating a mixture of nano silver wires and nano cesium tungsten bronze / ITO / ATO. The dispersion is then applied to a base film using a coating technique to form a protective layer. The film achieves electromagnetic shielding and infrared absorption functions through a one-step molding process. The protective film has a simple process and is relatively inexpensive.

[0020] Furthermore, the protective layer has only one layer, effectively avoiding the loss of visible light caused by multiple protective layers, avoiding complex production processes, and preventing operators from misplacing the product upside down. Therefore, the present invention can achieve protection against electromagnetic radiation information leakage and infrared intrusion through a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of the photoelectric information leakage protection film of the present invention;

[0022] Figure 2 Schematic diagram of electromagnetic leakage protection of the photoelectric information leakage protection film of the present invention;

[0023] Figure 3 Schematic diagram of infrared absorption operation of the photoelectric information leakage protection film of the present invention;

[0024] Figure 4 This is a spectral transmittance distribution diagram of the photoelectric information leakage protection film of Example 1.

[0025] in,

[0026] 1: Base layer 2: Protective layer 3: Adhesive layer 4: Protective layer

[0027] 5: Electromagnetic radiation signal 6: Reflection signal

[0028] 7: Transmission signal 8: Infrared intrusion signal

[0029] 9: Reflected light 10: Transmitted light DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions, beneficial effects and significant improvements of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following embodiments in combination with the drawings provided in the embodiments of the present invention. Obviously, all the described embodiments are only partial embodiments of the present invention, rather than all embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] The photoelectric information leakage protection film of the present invention only uses this specific layered structure to form a protective film, which can effectively prevent infrared laser information leakage and electromagnetic information leakage. The specific structure and preparation method are as follows:

[0032] Example 1

[0033] Reference Figure 1 A photoelectric information leakage protection film is provided with a base layer 1, a protective layer 2, an adhesive layer 3 and a protective layer 4 from bottom to top. The protective layer 2 is solidified on the top of the base layer 1, the adhesive layer 3 is adhered to the top of the protective layer, and the protective layer 4 is adhered to the top of the adhesive layer 3.

[0034] The base layer 1 and the protective layer are made of the same material, both of which are PET films made of transparent PET plastic with a thickness of 50 μm, and are used to provide support for the protective film on the basis of high light transmittance.

[0035] Protective layer 2 is a single-layer structure formed by coating a mixture of silver nanowires and nano-ITO (indium tin oxide) on the upper surface of the substrate. Multiple silver nanowires overlap and stack to form an irregular conductive grid. The silver nanowires and ITO are uniformly mixed at a weight ratio of 1:9. The silver nanowires have a diameter of 20nm and a length of 1μm, while the infrared absorbing and reflecting material is nano-ITO with a diameter of 20nm. The protective layer has a thickness of 10μm. Protective layer 2 includes silver nanowires and ITO. The silver nanowires provide protection against electromagnetic signals, while the ITO has strong infrared absorption and reflection properties. This allows for a single-step coating process to achieve protection against both infrared and electromagnetic signals.

[0036] The adhesive layer 3 is an acrylic adhesive, which is coated on the top of the protective layer 2 and is used to adhere the protective layer 2 and the protection layer 4. The thickness of the adhesive layer 3 is 10 μm.

[0037] The protective layer 4 is used to protect the shielding layer 2 and has a thickness of 10 μm.

[0038] The specific preparation method of the photoelectric information leakage protection film is as follows:

[0039] A prefabricated PET film with a thickness of 50 μm was used as the base layer 1;

[0040] 10 wt% silver nanowires and 90 wt% ITO powder were placed in acetone and ultrasonically stirred to form a suspension. The suspension was then coated on the surface of a prefabricated PET base layer 1 through a coating process. The base layer 1 was then dried at 150-185°C for 3-5 hours and then naturally cooled to form a precipitated protective layer 2 with a thickness of 10 μm.

[0041] After the protective layer 2 is cured, an acrylic adhesive is applied on the top of the protective layer 2 with a thickness of 10 μm. Before the adhesive layer 3 is air-dried, a 10 μm thick PET film is directly added on the top of the adhesive layer as a protective layer.

[0042] When in use, the base layer 1 or protective layer 4 of the photoelectric information leakage protection film is fixed to the device to be protected. Since the protective layer 2 has only one layer structure, it is prevented from being mistakenly pasted in reverse by the staff, thereby affecting the protection effect of the protection film.

[0043] Example 2

[0044] A photoelectric information leakage protection film is provided, from bottom to top, with a base layer 1, a protective layer 2, an adhesive layer 3, and a protective layer 4. The protective layer 2 is cured on top of the base layer 1, the adhesive layer 3 is adhered to the top of the protective layer, and the protective layer 4 is adhered to the top of the adhesive layer 3. This embodiment is similar to Example 1, and the common contents are not repeated here. Only the differences are described below.

[0045] Protective layer 2 is a single-layer structure formed by coating a mixture of silver nanowires and nano-arsenic trioxide (ATO) on the upper surface of substrate layer 1. Multiple silver nanowires are overlapped and stacked to form an irregular conductive grid. A uniform mixture of 20 wt% silver nanowires and 80 wt% ITO powder is used. The silver nanowires have a diameter of 20 nm and a length of 1 μm, while the infrared absorbing and reflecting material is nano-ATO with a diameter of 50 nm. The protective layer has a thickness of 150 μm. Protective layer 2 includes silver nanowires and ITO. The silver nanowires provide protection against electromagnetic signals, while the ITO has strong absorption and reflection properties for infrared light. This allows for a one-step coating process to achieve protection against both infrared and electromagnetic signals.

[0046] Example 3

[0047] This embodiment is similar to embodiment 1, and only the arrangement of the protective layer is different. The same contents will not be repeated here, and only the differences will be described below.

[0048] The protective layer 2 is a single-layer structure formed by a coating process on the upper surface of the base layer 1 after mixing nanosilver wires and nanocesium tungsten bronze. Multiple nanosilver wires are overlapped and stacked to form an irregular conductive grid. 90wt% nanosilver wires and 10wt% nanocesium tungsten bronze are uniformly mixed. The nanosilver wires have a diameter of 50nm and a length of 1μm, while the infrared absorption and reflection material is nanocesium tungsten bronze with a diameter of 30nm. The protective layer has a thickness of 100μm. The protective layer 2 includes nanosilver wires and nanocesium tungsten bronze. The nanosilver wires can provide protection against electromagnetic signals, and ITO has strong absorption and reflection functions for infrared light, thereby achieving protection against infrared and electromagnetic signals through one-step molding through coating.

[0049] The electromagnetic and infrared protection principles of the present invention are:

[0050] 1. Protection against electromagnetic information leakage

[0051] like Figure 2 As shown, when electromagnetic radiation is present, electromagnetic radiation signal 5 passes through base layer 1 and reaches protective layer 2. Because the silver nanowires in protective layer 2 form a conductive grid, this reflects electromagnetic reflection signal 6 from the protective layer. Because the protective layer formed by the silver nanowires and cesium tungsten bronze / ITO / ATO effectively blocks electromagnetic signal transmission, the transmitted signal 7 that can pass through the protective layer is very weak (indicated by a small arrow in the figure), thus preventing electromagnetic leakage from the incident direction through the protective film.

[0052] 2. Protection against infrared laser information leakage

[0053] like Figure 3 As shown, when the infrared laser is irradiated from the protective layer 4 of the protective film to the protective layer 2, the incident infrared light enters the protective film. Since the protective layer contains nano-cesium tungsten bronze / ITO / ATO, it has the function of effectively absorbing infrared laser. Therefore, most of the infrared transmitted light 8 is absorbed after entering the protective layer 2, a small part of the infrared reflected light 9 is reflected by the surface of the film, and a small part of the infrared transmitted light 10 passes through the protective layer 2 and the base layer 1 to form infrared output light.

[0054] In addition, if Figure 4 As shown, the applicant tested the electromagnetic shielding performance and spectral transmittance performance of the protective film of the present invention respectively. For electromagnetic shielding, the flange coaxial method was used for testing, and the data shown in Table 1 below were obtained; for light transmittance, a spectrophotometer was used for testing, and the data obtained were shown in Table 2. The visible light transmittance between 380-780nm reached 50%, and the transmittance between 900nm-1800nm ​​was less than 0.1%.

[0055] Table 1: Electromagnetic shielding effectiveness of the protective film at 30 MHz to 6 GHz prepared in Example 1

[0056]

[0057] Table 2: Spectral transmittance performance of the protective film prepared in Example 1

[0058]

[0059] From the above principles and test results, it can be seen that the present invention can effectively prevent both infrared laser information leakage and electromagnetic information leakage.

[0060] The applicant used the flange coaxial method and a spectrophotometer to conduct electromagnetic shielding performance tests and spectral transmittance performance tests on the protective films described in Examples 1-3, respectively. The test results are shown in Table 3 and Table 4 below, respectively:

[0061] Table 3 Electromagnetic shielding performance test of the protective films prepared in Examples 1-3

[0062]

[0063] Table 4 Spectral transmittance performance test of the protective films prepared in Examples 1-3

[0064]

[0065] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents, and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. Non-essential improvements, adjustments or replacements made by those skilled in the art based on the contents of this specification are all within the scope of protection required by the present invention.

Claims

1. A photoelectric information leakage protection film, comprising a base layer (1), characterized in that: The invention also includes a protective layer (2) solidified on the top of the base layer (1), wherein the base layer (1) is used to provide support for the protective film, and the protective layer (2) has a thickness of 1-100 μm, and is formed by mixing nano silver wires and indium tin oxide / cesium tungsten bronze / arsenic trioxide and then coupling it to the upper surface of the base layer (1) by coating in one step; wherein a plurality of nano silver wires are overlapped and stacked to form an irregular conductive grid; the weight ratio of the nano silver wires to indium tin oxide / cesium tungsten bronze / arsenic trioxide is between 1:9 and 9:1; and the protective layer (2) can reflect electromagnetic signals and absorb incident infrared laser light from the incident direction.

2. The photoelectric information leakage protection film according to claim 1, characterized in that: The photoelectric information leakage protection film comprises, from bottom to top, the base layer (1), the protection layer (2), the adhesive layer (3) and the protective layer (4), wherein the adhesive layer (3) is adhered to the top of the protection layer (2), and the protective layer (4) is adhered to the top of the adhesive layer (3); The base layer (1) and the protective layer (4) are transparent films, the materials of the base layer (1) and the protective layer (4) are selected from polyethylene terephthalate, polyvinyl butyral or ethylene-vinyl acetate copolymer, and the thickness of the base layer (1) is 5-100 μm; The adhesive layer (3) is an acrylic adhesive, which is coated on the top of the protective layer (2) and is used to adhere the protective layer (2) and the protective layer (4). The thickness of the adhesive layer (3) is 10-50 μm; The protective layer (4) has a thickness of 1-100 μm and is used to protect the protective layer (2) from damage and contamination before mounting.

3. The photoelectric information leakage protection film according to claim 1, characterized in that: The protective film has a transmittance of less than 0.1% for visible light with a wavelength between 900nm and 1800nm, and a shielding effectiveness of more than 30db for electromagnetic waves with a frequency between 30MHz and 18GHz.

4. A method for preparing the photoelectric information leakage protection film according to claim 2 or 3, characterized in that: include: Nano silver wires and indium tin oxide / cesium tungsten bronze / arsenic trioxide in a weight ratio of 1:9 to 9:1 are uniformly mixed and placed in acetone, and ultrasonic stirring is used to form a suspension. The suspension is coated on the surface of a prefabricated base layer (1) through a coating process; and the mixture is dried at 150°C-185°C for 3-5 hours and then naturally cooled to form a precipitated protective layer (2).

5. The preparation method according to claim 4, characterized in that: The base layer (1) of the photoelectric information leakage protection film is installed on the device to be protected.

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