Rearview mirror rearview mirror has a vision problem, that is, the mirror can be reflected to the range. The industry has three elements of the horizon, that is, the distance between the driver's eye and the rearview mirror; the size of the rearview mirror and the radius of curvature of the rearview mirror.

These three elements have a certain relationship between the rearview mirror when the distance and size of the same, the smaller the radius of curvature of the mirror, the mirror reflects the greater the horizon. When the radius of curvature of the same mirror, the larger the size of the mirror, the mirror reflects the greater the horizon. However, things have a dual nature, although the curvature of the mirror radius of the smaller field of view the greater the scope, but at the same time the mirror reflects the greater degree of deformation of the object, which some like "haha mirror", often cause the driver's illusion.

From the point of view of traffic safety, there is a problem of image distortion. Industry standards, the plane mirror distortion rate of not more than 3%, convex mirror distortion rate of not more than 7%, the requirements can not reflect the distortion of the physical image. Therefore, the radius of curvature of the mirror there is a limit, the industry standard specifies the radius of curvature of the rearview mirror R1200, the radius of curvature of the rear view mirror is infinite (plane mirror). At the same time, the rearview mirror also has a reflectivity indicator. The larger the reflectance, the sharper the image of the mirror. The size of the reflectance is related to the mirror surface reflective film material.

Automotive rearview mirror reflective film generally silver and aluminum as the material, their minimum reflectivity of 80%. High reflectivity in some occasions there will be side effects, such as night driving in the back of the car headlamps under the irradiation, the reflection of the rearview mirror will make the driver a sense of dazzling, affecting traffic safety. Therefore, the general use of prism mirror, although the mirror is flat, but the cross-sectional shape is prismatic, it uses the prismatic surface reflectivity and reflect the reflectivity is not the same characteristics, to achieve no glare requirements. Daylight with a reflectivity of 80% of the silver or aluminum inside the reflective film, the evening with the reflectivity of only about 4% of the surface glass. To this end, only a little bit of the night position of the rearview mirror rotation angle on the line.

There is an automatic discoloration of the rearview mirror, its electronic photometric detector can automatically distinguish the outside of the natural light and imposed the light source, through the current changes in a few seconds to adjust the mirror color material, from colorless to colored to adjust Inside the rearview mirror reflectivity, thus solving the dazzling problem. The distance between the driver's eye and the rearview mirror, that is, the position of the rearview mirror, directly affects the horizon of the rearview mirror, the clarity and the size of the car profile, and is important for traffic safety. Therefore, the rearview mirror installation location requirements to meet the industry standard vision requirements; rearview mirror should be as close as possible to the driver's eyes, should facilitate the driver to observe the head and eye rotation as small as possible; rearview mirror should be installed in the body up and down Vibration at the smallest position.

Take the present car as an example, the exterior mirrors are mainly assembled on the front door, the control mode is electric and manual. The exterior of the lens of the electric exterior mirrors is equipped with a drive mechanism, which consists of a small reversible DC motor, a reduction gear and an electromagnetic clutch. The driver adjusts the upper and lower left and right mirrors in the vehicle control switch, and the adjustment range is within 30 degrees , And can be folded. Manual rear mirrors are mostly leveraged, the driver in the driver's seat on the swing door corresponding to the small handle, you can adjust the mirror angle from top to bottom, this manual rearview mirror structure is relatively simple, generally assembled in the economy car on.

Outer mirrors outline contours not only affect the appearance of the body, but also affect the body size, the industry standard car exterior mirrors can not exceed the installation location of the car 250 mm out of the provisions. At the same time, due to the general car's speed, wind resistance and noise are important issues to be considered by the designer, so the outline of the exterior mirror should be aerodynamically, with smooth lines to minimize wind resistance and wind noise.