Thermochromic materials can change the temperature of the material under the control of the temperature control device after sensing the brightness and chromaticity information of the background light, thereby presenting the brightness and chromaticity consistent with the background. Thermochromic materials can be divided into inorganic thermochromic materials and organic thermochromic materials according to their constituent materials; they are divided into reversible and irreversible thermochromic materials according to the color change method, but only reversible thermochromic materials can be used in dynamic stealth (stealth materials) ). Inorganic thermochromic materials have multiple discoloration mechanisms such as crystal change, chemical reaction and thermal decomposition.
The United States once introduced a thermochromic camouflage system that can be applied to the surface of tanks and vehicles. The camouflage system consists of a thermochromic material, a conductive metal plate, a thermoelectric module, a temperature sensor and a heat absorber from top to bottom. The conductive metal plate generally selects the AI board with higher strength and hardness and faster heat transfer; the thermoelectric module is able to Electric energy is converted into a solid device with a temperature gradient to heat or cool a conductive metal plate; a temperature sensor and a heat sink are combined to control the temperature of the thermoelectric module to avoid overheating; the outermost color-changing material generally uses liquid crystal materials, such as color-changing liquid crystals, in order to avoid discoloration The liquid crystal is in direct contact with the outside world. Place it in a polyester box or any container that avoids contact with the outside world. The thermoelectric module controls the temperature of the entire system, and transfers heat to the color-changing liquid crystal through the conductive metal plate. The color-changing liquid crystal can present different colors according to the temperature change within a few seconds, such as red at 20°C and green at 34-35°C. It is blue at 46°C. The specific composition of the color-changing liquid crystal is still confidential.
Although some progress has been made in the research of thermochromic materials, there are some defects such as few color changes, narrow controllable range of brightness, and the temperature of discoloration is mostly in the high temperature area.