What is the Imaging Principle of Car Rearview Mirrors?
2 Answers
Rearview mirrors involve the concept of a field of view, which refers to the range that the mirror surface can reflect. The industry proposes three key elements of the field of view: the distance between the driver's eyes and the rearview mirror, the size of the rearview mirror, and the curvature radius of the mirror. These three elements are interrelated. When the distance and size of the rearview mirror are the same, a smaller curvature radius of the mirror surface results in a larger reflected field of view. Below is an introduction to the types of rearview mirrors classified by installation position: 1. Interior rearview mirror: The interior rearview mirror allows the driver to confirm the rear scene without significantly altering their forward line of sight while driving. 2. Exterior rearview mirror: Passenger cars typically mount the exterior rearview mirror on the doors. In Japan, some domestic vehicles also mount them on the fenders. 3. Underview mirror: The underview mirror enables the driver to see areas beyond the front and rear wheels beneath the car body through the mirror directly in front of the driver's seat. This helps the driver observe whether there are people or obstacles near the wheels or the sides of the car when reversing or starting forward, thereby avoiding injury to people or damage to objects and the vehicle, providing convenience and safety to the driver.
The imaging of car rearview mirrors actually relies on the principle of light reflection, just like when we look into a mirror. However, ordinary rearview mirrors use flat mirrors, which reflect light from behind the car directly into the driver's eyes, making the distance appear similar to reality. But the exterior rearview mirrors are different—they are designed as convex mirrors to reduce blind spots. These mirrors have a slight curvature, making objects appear smaller and farther away, but they significantly expand the field of vision. Especially when turning or changing lanes, convex mirrors help you spot small electric bikes or bicycles that might be hidden by the car body. By the way, if the mirror gets blurry due to rain, many cars now come with a heating function to quickly evaporate the water mist.
