An electrically controlled camouflage device with uniform color change over a large area and its preparation method and application

Abstract

The present invention discloses an electrically controlled camouflage device with uniform color change over a large area, and a preparation method and application thereof. The electrically controlled camouflage device is polygonal, and includes: a substrate; a heating layer for electrically controlled heating, which uses hydroxypropyl methylcellulose as a polymer substrate and doped with silver nanowires as a conductive material; a protective layer made of polyimide; a backlight layer coated with black ink; and a thermochromic layer coated with thermochromic liquid crystal ink, wherein the thermochromic layer switches colors under the temperature control of the heating layer. The preparation technology of the camouflage device with uniform color change over a large area provided by the present invention does not need to pay special attention to the substrate. Each functional layer only needs to be scraped and coated on the glass substrate in sequence to form a film. The operation is simple, practical, easy to produce and prepare, and low in cost. The preparation technology of the camouflage device with uniform color change over a large area provided by the present invention can easily and quickly achieve uniform color change over a large area.

Description

Technical Field

[0001] The present invention relates to the technical field of optical uniform color change anti-counterfeiting, and in particular to an electrically controlled camouflage device with large-area uniform color change, and a preparation method and application thereof. Background Art

[0002] Camouflage equipment has a wide range of applications in military, security, outdoor leisure, and fashion design. Although traditional preparation methods can achieve the preparation of color-changing camouflage. However, the uniformity of its color change and the realization of uniform color change over a large area are still a challenge, and it is necessary to ensure that the color change effect of the material is consistent over the entire surface. Due to the following reasons, it is difficult for the existing technology to achieve the preparation of uniform color-changing materials over a large area, which also greatly limits its flexibility and extensiveness in practical applications. 1) Material uniformity: It is very difficult to maintain the consistency of material composition and microstructure over a large area, which directly affects the uniformity of the color change effect; 2) Coating process: The uniformity of the coating is crucial to achieve uniform color change. Coating a uniform layer of color-changing material over a large area is a technical challenge; 3) Thermal management: Color-changing materials are usually sensitive to temperature, and uneven heat distribution over a large area may lead to inconsistent color change effects; 4) Light management: The uniformity of light is very important for photochromic materials. Maintaining consistent illumination over a large area is a challenge; 5) Electronic control: For electrochromic materials, precise electronic control is required to achieve uniform color change, which may require complex circuit design to achieve over a large area; 6) Cost-effectiveness: Technologies that achieve uniform color change over a large area are often costly, which limits their feasibility in certain applications; 7) Durability: Large-area color-changing materials need to maintain stability and durability under various environmental conditions, which is technically a challenge.

[0003] There are many existing technologies for achieving large-area color change, but it is difficult to achieve uniform color change over a large area. For example, electrochromic windows use electric fields to change the color of glass. Although these windows can cover large areas, it is a technical challenge to maintain uniform color change over the entire window. Thermochromic coatings can change color according to temperature. On small areas, these coatings can change color evenly, but on large areas, uneven temperature distribution may cause uneven color change. Electronic ink displays use charges in microcapsules to control color display. Although these displays can be made very large, it is a technical challenge to ensure uniform color change over the entire display. Some smart textiles can change color according to environmental changes. On small areas, these materials can change color evenly, but on large areas, maintaining uniformity may require more sophisticated material and process control. To overcome these challenges, researchers are developing new materials, improving manufacturing processes, and exploring new design concepts. Through interdisciplinary cooperation and technological innovation, there may be more solutions to achieve uniform color change over large areas in the future. Summary of the invention

[0004] Based on this, the present invention provides an electrically controlled camouflage device with uniform color change over a large area and a preparation method thereof, so as to solve the problem that it is difficult to achieve uniform color change over a large area in the prior art.

[0005] To achieve the above object, the present invention provides an electrically controlled camouflage device with uniform color change over a large area. The electrically controlled camouflage device is polygonal and includes:

[0006] substrate;

[0007] A heating layer for electrically controlled heating, which uses hydroxypropyl methylcellulose as a polymer substrate and doped with silver nanowires as a conductive material; the heating layer is composed of a plurality of small rectangular sheets arranged in a row and having the same length and width, and the small rectangular sheets at both ends are respectively connected to electrodes; any two adjacent small rectangular sheets are arranged close to each other, and a slit on one side and a connecting portion on the other side are formed between the two adjacent small rectangular sheets along the length direction of the small rectangular sheets, the connecting portion is used to connect the two adjacent small rectangular sheets into a whole, and the adjacent connecting portions are staggered up and down, the total length of the slit and the connecting portion is equal to the length of the small rectangular sheet, and the ratio of the length of the connecting portion to the width of the small rectangular sheet is 1:2-2:1;

[0008] The protective layer is made of polyimide, which is used to prevent the substrate and the heating layer from being oxidized, and also provides dust and water resistance, and can resist scratches and wear, protecting the underlying material from physical damage;

[0009] The backlight layer is a black film coated with black ink. Its function is to enhance the color saturation and contrast and improve the overall display effect. The backlight layer can also provide a uniform light source to ensure that the image is clearly visible.

[0010] The thermochromic layer is formed by coating thermochromic liquid crystal ink, and the thermochromic layer realizes color switching under the temperature control of the heating layer.

[0011] As a further preferred technical solution of the present invention, the color change temperature range of the thermochromic layer is 20-60 degrees.

[0012] As a further preferred technical solution of the present invention, the electrically controlled camouflage device is in the shape of a triangle, rectangle, rhombus or trapezoid, and more preferably a square.

[0013] As a further preferred technical solution of the present invention, the electrically controlled camouflage device is a rectangle with a size ranging from 2.5 cm×2.5 cm to 1 m×2 m.

[0014] As a further preferred technical solution of the present invention, the substrate is a glass sheet or a plastic sheet.

[0015] As a further preferred technical solution of the present invention, the thickness of each of the heating layer, the protective layer, the backlight layer and the thermochromic layer is 1 μm-50 μm.

[0016] As a further preferred technical solution of the present invention, the width of the slit is 0.1mm-30mm, and the width of the small rectangular sheet in the heating layer is not greater than 15cm, and the width of the slit is 1 / 40-1 / 3 of the width of the small rectangular sheet. As the number of slits on the heating layer increases, the width of each small rectangular sheet becomes narrower, so that the heating is more uniform, and the width of the small rectangular sheet is further preferably 0.3-1.0cm.

[0017] According to another aspect of the present invention, the present invention also provides a method for preparing an electrically controlled camouflage device, which comprises the following steps:

[0018] S1. Mixing silver nanowires and hydroxypropyl methylcellulose in a solvent, shaking thoroughly in a centrifuge, coating the solution on the surface of a substrate, and then thermally curing to form a film, and then laser etching the cured film to form a slit to obtain a heating layer; wherein the solvent is at least one of deionized water, ethanol, and isopropanol;

[0019] S2, coating the polyimide coating on the surface of the heating layer, and thermally curing it to obtain a protective layer;

[0020] S3, coating the black ink on the surface of the protective layer, thermally curing or air-drying, to obtain a backlight layer;

[0021] S4, coating the thermochromic liquid crystal ink on the surface of the backlight layer, thermally curing or air-drying, to obtain a thermochromic layer.

[0022] As a further preferred technical solution of the present invention, in step S1, the mass ratio of silver nanowires, hydroxypropyl methylcellulose and solvent is 3:2:1 to 1:2:3, and the concentration of hydroxypropyl methylcellulose is 1 mg / mL-8 mg / mL.

[0023] As a further preferred technical solution of the present invention, in step S1, the laser wavelength used for laser etching is at least one of 266nm, 355nm, 375nm, 395nm, 405nm, and 435nm.

[0024] According to another aspect of the present invention, the present invention also provides an application of an electrically controlled camouflage device with large-area uniform color change for camouflage equipment, wherein the surface of the camouflage equipment is covered with a plurality of electrically controlled camouflage devices connected to each other, and the camouflage equipment also includes a controller, which is electrically connected to each of the electrically controlled camouflage devices.

[0025] The electrically controlled camouflage device of the present invention can be applied to the following fields for camouflage equipment:

[0026] Military field: Integrate electronically controlled camouflage devices into military uniforms, tents, vehicles and other equipment, so that they can be adjusted in real time according to the color and pattern of the surrounding environment to achieve anti-counterfeiting effects, thereby improving the concealment of soldiers and equipment, reducing the risk of being discovered by the enemy, and enhancing battlefield survivability.

[0027] Outdoor leisure: Cover outdoor clothing, tents, backpacks and other equipment with electronically controlled camouflage devices to achieve anti-counterfeiting effects. For example, hunters or wildlife observers can use these devices to better camouflage themselves in different seasons and environments, reduce interference with animals, and increase the success rate of observation and hunting.

[0028] Fashion design: Designers can use electronically controlled camouflage devices to make clothing, accessories and other fashion items, creating unique designs that can change according to environmental changes, thereby providing a novel fashion experience, making the wearer more eye-catching in different occasions and environments, and increasing the attractiveness and market competitiveness of fashion items.

[0029] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0030] 1) The preparation technology of the camouflage device with large-area uniform color change provided by the present invention does not need to pay special attention to the substrate. Each functional layer only needs to be scraped and coated on the glass substrate in sequence. The operation is simple, practical, easy to produce and prepare, and low in cost.

[0031] 2) The preparation technology of the camouflage device with large-area uniform color change provided by the present invention can simply and quickly achieve large-area uniform color change.

[0032] 3) The preparation technology level of the camouflage device with large-area uniform color change provided by the present invention is relatively high. Only by laser etching the serpentine and U shapes can the uniform temperature distribution be guaranteed.

[0033] 4) The camouflage device with large-area uniform color change provided by the present invention can be applied to many fields, including military, security, outdoor leisure, fashion design and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] Figure 1 The figure is a schematic diagram of the device stacking, where TLC lin refers to the thermochromic layer of liquid crystal material, Black lin refers to the backlight layer, cPI refers to the protective layer, AgNWs / HPMC refers to the heating layer, and glass refers to the glass substrate.

[0036] Figure 2The infrared cameras of the samples of Example 1 and Comparative Example 1 show a comparison of uniform colors, wherein the sample before optimization refers to the sample of Comparative Example 1, and the sample after optimization refers to the sample of Example 1.

[0037] Figure 3 The actual color (red, green, blue) changes of the samples of Example 1 and Comparative Example 1 and the infrared images thereof, wherein the sample before optimization refers to the sample of Comparative Example 1, and the sample after optimization refers to the sample of Example 1.

[0038] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0039] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0040] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0041] Embodiment 1:

[0042] The method for preparing a large-area uniformly discolored electrically controlled camouflage device provided in this embodiment specifically comprises the following steps:

[0043] Step S1, silver nanowires: hydroxypropyl methylcellulose HPMC (5 mg / mL): ethanol are fully mixed in a ratio of 1:1.5:2, shaken in a centrifuge, and allowed to stand for 5 minutes; 500 μL is taken and scraped on a 5×5 cm square glass substrate (thickness 3 μm, scraping substrate temperature is 80°C); then placed on a hot stage at 100°C for curing for 5 minutes, and film formation is waited; a pattern is drawn on a laser machine, and a laser etching route for forming a slit is designed on the film, with an etching power of 4 W, an etching speed of 800 mm / s, and an etching frequency of 100°C. The etching rate is 60.000kHz. By etching four equally spaced slits, the whole film is formed into five small rectangular pieces arranged from left to right. Any two adjacent small rectangular pieces are arranged close to each other, and any two adjacent small rectangular pieces are formed with a slit on one side and a connecting part on the other side along the length direction of the small rectangular piece. The connecting part is used to connect the two adjacent small rectangular pieces into a whole, and any two adjacent connecting parts are staggered up and down (that is, each small rectangular piece is connected in sequence in an S-shaped serpentine structure to form a whole). The length of each small rectangular piece (up and down direction) is 50mm, and the width of the small rectangular piece (left and right direction) is 8.4mm; the slit width of the etched slit is 2mm, and the length of the slit is 41.6mm. Finally, a heating layer located on the glass sheet substrate is formed, and an electrode is connected to each end of the small rectangular piece on the left and right sides of the heating layer. The electrode is used to connect to the controller, and the controller is used to control the power supply to make the heating layer heat up.

[0044] Step S2, applying the polyimide coating to a thickness of 10 μm on the surface of the heating layer, and then performing a program heating curing: 40°C for 5 min, 60°C for 10 min, and 90°C for 30 min, to obtain a protective layer on the heating layer;

[0045] Polyimide coating configuration:

[0046] 200 mg of 4,4'-dihydroxydiphenyl oxide (ODA) was placed in a round-bottom flask, OPDA (4,4'-biphenyl dicarboxylic anhydride) was added and stirred for one hour under ice bath conditions, and then 300 mg of NMP (N-methylpyrrolidone) was added and stirred at room temperature using a magnetic stirrer until it was completely dissolved.

[0047] S3, applying black ink to the surface of the protective layer with a thickness of 10 μm by scraping, and then curing at 50° C. for 10 minutes to obtain a backlight layer of a black film on the protective layer;

[0048] The black ink was purchased from the Aowei Printing Materials Taobao store. The production company is Zhongcheng Ink Store in Chenghai District, Shantou City. The brand is: Japan Jujo Ink, model: 9092.

[0049] S4, coating the thermochromic liquid crystal ink with a thickness of 40 μm on the surface of the backlight layer, and then curing at 60° C. for 20 minutes to obtain a thermochromic layer on the backlight layer. Figure 1 An electrically controlled camouflage device with a stacked structure as shown.

[0050] Configuration of thermochromic liquid crystal ink:

[0051] Weigh 5mg of 5CB (4-cyano-4'-pentylbiphenyl) and 4mg of 12CB (4-cyano-4'-dodecylbiphenyl) in a beaker. Add 25mg of R811 and 5mg of R5011 chiral agents. Then weigh 1000μL of PVA polymer (20% PVA and 80% water) and add it to the mixture. Stir the mixture at 800 rpm for 12 hours to ensure that the liquid crystal is evenly dispersed in the polymer matrix to form a uniform thermochromic liquid crystal ink. The temperature response characteristics of the film formed by coating the thermochromic liquid crystal ink are red at 24℃~26℃, green at 29℃~31℃, and blue at 33℃~36℃.

[0052] Comparative Example 1:

[0053] As a control experiment of Example 1, a large-area non-uniform color-changing electrically controlled camouflage device was prepared by a method basically the same as that of Example 1, the only difference being that laser etching was not used in step S1, that is, the cured film was directly used as a heating layer.

[0054] The two groups of electrically controlled camouflage devices prepared in Example 1 and Comparative Example 1 were respectively connected to a power supply with a power of 0.5 W for comparative testing, as follows:

[0055] Figure 2 The infrared camera presents a comparison chart of uniform color. In the chart, A1, A2, and A3 are infrared camera images of the device in Example 1 when it is connected to 0.2W power for 20s, 40s, and 60s, and B1, B2, and B3 are infrared camera images of the device in Comparative Example 1 at the same power for 20s, 40s, and 60s. It can be clearly seen that the image color of Example 1 is more uniform.

[0056] Figure 3The changes of red, green and blue colors, in the figure, C1, C2, C3 are the real pictures of the red, green and blue colors of the device of Example 1 connected to 0.5W power at 0s, 10s and 60s; C4, C5, C6 are the infrared camera pictures of the red, green and blue colors of Example 1 connected to 0.5W power at 0s, 10s and 60s; D1, D2, D3 are the real pictures of the device of Comparative Example 1 at the same power at 0s, 10s and 60s, which are used for comparison with C1, C2, C3; D4, D5, D6 are the infrared camera pictures of the device of Comparative Example 1 at the same power at 0s, 10s and 60s, which are used for comparison with C4, C5, C6. By comparison, it can be seen that the image color of Example 1 is more uniform.

[0057] Embodiment 2:

[0058] The electrically controlled camouflage device prepared in Example 1 is used in applications of camouflage equipment.

[0059] Several electrically controlled camouflage devices prepared in Example 1 are assembled together and covered on the surface of clothes to form a camouflage uniform covered with color-changing blocks. The camouflage uniform is provided with an STM32 controller connected to all the electrically controlled camouflage devices. The controller is also connected to a color sensor. The sensor collects color information of the wearer's environment. The controller controls the color change of each electrically controlled camouflage device by controlling the heating temperature of the heating layer, so that the worn camouflage uniform is integrated with the environmental color to achieve a concealment effect.

[0060] In practical applications, the thermochromic layer of the electrically controlled camouflage device can also use thermochromic liquid crystal inks with more types of color changes, so that the camouflage device can better match the ambient color. For example, if an outdoor photographer needs to take pictures, he can wear the camouflage uniform and intelligently adjust the color of the clothing according to the color of the surrounding environment to achieve perfect integration with the natural environment; for example, in the autumn forest or desert, it can change to a reddish-brown tone that matches the environment; in the summer forest, it becomes a rich green; and around the lake, it presents the blue of the lake water. This color change allows photographers to remain concealed in various natural environments, so that they can observe and photograph wild animals more closely and capture their most natural and real moments. The preparation of thermochromic liquid crystal inks with multiple color changes belongs to the prior art, and the specific types and color change principles are not described here.

[0061] Although specific embodiments of the present invention are described above, those skilled in the art should understand that these are merely examples and that various changes or modifications may be made to the embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is limited only by the appended claims.

Claims

1. An electrically controlled camouflage device with uniform color change over a large area, characterized in that: The electrically controlled camouflage device is polygonal, and includes: substrate; A heating layer for electrically controlled heating, which uses hydroxypropyl methylcellulose as a polymer substrate and doped with silver nanowires as a conductive material; the heating layer is composed of a plurality of small rectangular sheets arranged in a row and having the same length and width, and the small rectangular sheets at both ends are respectively connected to electrodes; any two adjacent small rectangular sheets are arranged close to each other, and a slit on one side and a connecting portion on the other side are formed between the two adjacent small rectangular sheets along the length direction of the small rectangular sheets, the connecting portion is used to connect the two adjacent small rectangular sheets into a whole, and the adjacent connecting portions are staggered up and down, the total length of the slit and the connecting portion is equal to the length of the small rectangular sheet, and the ratio of the length of the connecting portion to the width of the small rectangular sheet is 1:2-2:1; Protective layer, made of polyimide; Backlight layer, a black film coated with black ink; Thermochromic layer, formed by coating thermochromic liquid crystal ink, the thermochromic layer changes color under the temperature control of the heating layer; The electrically controlled camouflage device is a rectangle with a size ranging from 2.5 cm×2.5 cm to 1 m×2 m; the thickness of each layer of the heating layer, the protective layer, the backlight layer and the thermochromic layer is 1 μm-50 μm; the width of the slit is 0.1 mm-30 mm, and the width of the small rectangular piece in the heating layer is not more than 15 cm, and the width of the slit is 1 / 40-1 / 3 of the width of the small rectangular piece.

2. The electrically controlled camouflage device with large-area uniform color change according to claim 1, characterized in that: The electrically controlled camouflage device is in the shape of a triangle, a rectangle, a rhombus or a trapezoid.

3. The electrically controlled camouflage device according to claim 1, characterized in that: The substrate is a glass sheet or a plastic sheet.

4. A method for preparing a large-area uniformly discolored electrically controlled camouflage device according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Mixing silver nanowires and hydroxypropyl methylcellulose in a solvent, shaking thoroughly in a centrifuge, coating the solution on the surface of a substrate, and then thermally curing to form a film, and then laser etching the cured film to form a slit to obtain a heating layer; wherein the solvent is at least one of deionized water, ethanol, and isopropanol; S2, coating the polyimide coating on the surface of the heating layer, and thermally curing it to obtain a protective layer; S3, coating the black ink on the surface of the protective layer, thermally curing or air-drying, to obtain a backlight layer; S4, coating the thermochromic liquid crystal ink on the surface of the backlight layer, thermally curing or air-drying, to obtain a thermochromic layer.

5. The method for preparing a large-area uniformly discolored electrically controlled camouflage device according to claim 4, characterized in that: In step S1, the mass ratio of silver nanowires, hydroxypropyl methylcellulose, and solvent is 3:2:1 to 1:2:3, and the concentration of hydroxypropyl methylcellulose is 1 mg / mL-8 mg / mL.

6. The method for preparing a large-area uniformly discolored electrically controlled camouflage device according to claim 4, characterized in that: In step S1, the laser wavelength used for laser etching is at least one of 266 nm, 355 nm, 375 nm, 395 nm, 405 nm, and 435 nm.

7. An application of the electrically controlled camouflage device with large-area uniform color change according to any one of claims 1 to 3 in camouflage equipment, characterized in that: The surface of the camouflage device is covered with a plurality of electrically controlled camouflage devices connected to each other. The camouflage device also includes a controller, and the controller is electrically connected to each of the electrically controlled camouflage devices.

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