1. The lamp is in an environment with high humidity and high temperature, and the air humidity inside the lamp is relatively high. When the ambient temperature decreases, the water vapor in the lamp cannot sufficiently flow and diffuse into the environment, and remains at a relatively high level. Humidity, fogging occurs when the temperature in some areas of the lamp falls below the local critical temperature of water vapor.
2. The temperature in the area where the light energy is irradiated and the air circulates is very high, but the headlights cannot irradiate the light area, and the temperature in the area where the air circulation is not smooth will be very low, which will lead to uneven temperature distribution in the lamp and form a larger area . Temperature difference; especially in the lamp cavity, due to its uneven surface, it provides a very favorable place for water vapor condensation.