The latest developments of visible light stealth materials are mainly manifested in two aspects. One is the research and development of smart stealth materials; the other is the application of nano stealth materials in camouflage fabrics. Visible light "smart" stealth material is a material system with "chameleon" characteristics. Therefore, intelligent stealth materials are coated or doped on weapons and equipment such as tanks, armored vehicles, and aircraft. . Currently, the smart stealth materials under development include: photochromic stealth materials, thermochromic stealth materials and electrochromic stealth materials.
Under the action of light of a certain wavelength and intensity, the molecular structure of photochromic materials changes, causing the change of the material's light absorption peak, and finally causing the color to change, achieving the purpose of invisibility. Recently, the United States, France, Japan and other countries all have research results in this area. The United States embeds highly active diacetylene segments in polyurethane molecules. Under appropriate conditions, diacetylene polymerizes into polydiacetylene, forming a conjugated structure with free electrons, which changes the color and light intensity of the entire material. On this basis, sensors and controllers are added to the material system, and a narrow band pass filter with a SiC photodetector can be used to identify the wavelength and light intensity of the environment, and then the output signal is transmitted to the microprocessor through the analog-to-digital converter. Recognize and process, and issue control instructions to change the color and color intensity of the material, so as to achieve the effect of invisibility.
The Parks Company of the United States has developed a photo-reactive lens that can be installed on the shell of a military vehicle and has a stealth effect. The lens is hexagonal, made of glass, plastic or other transparent materials, and contains photoreactive materials of different colors, and the brightness can be changed according to the intensity of the irradiated light. The surface of the lens is made of uneven structure in order to form uneven light reflection on the surface of the lens. A layer of reflective film is deposited on the surface of the lens to greatly reduce the reflectivity of the lens. The lens can be covered on the outer surface of the vehicle through an adhesive layer. According to reports, when light is irradiated, the light-reactive lens becomes darker, which effectively reduces the contrast between the bright surface and the shadow surface of the vehicle, and achieves a good match between the vehicle and the background, so as to achieve the purpose of stealth.
In addition, the United States successfully developed an intelligent color-changing coating in 2007 and applied for patent protection. From the inside to the outside, the entire coating consists of a self-healing layer, a visual display layer, a new material layer, an artificial intelligence network layer, a sensor component layer, an energy layer, and an anti-corrosion layer. When the anti-corrosion layer feels damage from the outside or a large enough color or brightness change, the sensor combination layer can transmit the obtained signal data to the artificial intelligence network layer, and the artificial intelligence network processes the signal and sends it to the visual display layer. The visual display layer will change its own color or pattern to achieve consistency with the background environment and achieve visual invisibility.