Research On Non-electric Readout Thermal Detection Technology Based On Thermo-optic Effect Of Liquid Crystal

Much attention has been paid to thermal irradiation detectors for their wide applications. Compared with cooled detectors, uncooled thermal imaging devices have many advantages, such as small dimension, low cost, and superior reliability. In recent years, with the infrared detect imaging technology rapidly developing, uncooled detection technology meets the technical bottlenecks, and the key problem is lacking of high-performance materials. There are many ways to solve this problem, such as using the new way for the signal generation and reading, or looking for new materials.Based on the optical rotation property of cholesteric liquid crystals(CLCs), an optical readout infrared detect imaging system is designed. The core of the system is the infrared sensitive device composed of the infrared liquid crystal box and CLCs. In this article, the optical rotation characteristic of CLCs with temperature changing, the production process of infrared absorption thin film, and orientation thin film in the infrared liquid crystal box are studied. In order to study the optical rotation characteristic of CLCs, a measuring optical path is designed. The impact of the rate of temperature change, S811 content, and the angle between the two polarizers on the optical rotation is studied, and the samples of CLCs that meet the imaging requirements are produced. In the production process of infrared liquid crystal box, the ITO prepared by RF magnetron sputtering is selected as the infrared absorption material. The impact of the process parameters on the thickness, optical properties and electrical properties of ITO thin film are also researched. The optimal technological parameters are obtained for ITO thin film with the infrared absorption of 58%. On the other hand, the orientation material is polyimide. Our study focuses are the impacts of the concentration of polyimide solution, the speed of spinning coater, temperature and time of thermal processing on the thickness of the orientation thin film. With a lot of experiments, the samples of PI thin film are obtained that the thickness is 63nm after curing, and the optical properties of the samples are also analyzed.In this subject, a new method for optical readout infrared detection imaging is achieved. This optical readout system does not need the cooling device and metal wires, and it does not produce additional heat on the detector, so it provides a new idea for the application of liquid crystal material and the optical readout infrared detection imaging technology.