Automatic laser detection and protection device based on LCD light switch

A set of automatic detection and protection device of the laser was designed in order to realize the automatic detection and protection against arbitrary wavelength laser according to the principle of phototriode,electromagnetic relay and liquid crystal electro-optic effect experiments. Based on the theoretical analysis and experimental verification, phototriode photocurrent was formed when exposed to the laser radiation. The amplification circuit and an electromagnetic relay switch were used to control the output voltage of 5V and close liquid crystal voltage switch in a short time. When subjected to laser irradiation, the liquid crystal screen was substantially opaque, and returned to the transparent state at the end of the laser pulse. The results showed a design of laser protective glasses, blocking the laser irradiation and allowing ordinary bright light through at ordinary time.