Car rearview mirrors are located on the left and right sides of the car's head, reaching the front of the car's interior. The rearview mirror of the car reflects the situation at the back, side and underneath of the car, so that the driver can indirectly see the situation at these locations. It acts as a "second eye" and expands the driver's field of vision. Car rearview mirrors are important safety parts, and their mirrors, shapes and handling are quite particular. The quality and installation of the rear-view mirrors have corresponding industry standards, which cannot be arbitrary. The rear-view mirror is divided into installation positions, and is divided into external rear-view mirror, lower rear-view mirror and internal rear-view mirror. Divided by usage, the exterior rear-view mirror reflects the rear side of the car, the lower rear-view mirror reflects the front and bottom of the car, and the inner rear-view mirror reflects the rear and interior conditions of the car. The use is different, and the mirror structure will be different. There are mainly two types of mirrors in general rearview mirrors. One is a flat mirror. As the name implies, the mirror is flat. In terms of terms, the surface radius of curvature R is infinite. This is the same as ordinary household mirrors. This kind of flat mirror is often used as a rearview mirror. The other is a convex mirror, which has a spherical surface with different curvature radii. Its image is smaller than that of the eye, but the field of view is large, as if the camera is a "wide-angle lens". This convex mirror is often used as an exterior mirror And under the rearview mirror. Passenger cars and other light passenger cars are generally equipped with exterior and interior mirrors, and large commercial vehicles (buses and trucks) are generally equipped with exterior, bottom, and interior mirrors