Because convex mirrors can increase the field of view and reduce blind spots.
The role of the car rearview mirror itself is to see the situation behind the car and increase driving safety. Designed as a convex mirror, it can see the situation behind the car in a wider range, reducing the blind spot of the rear and side rear.
The design of the previous car rearview mirror was not a convex mirror, but a flat mirror, so that you could only see the situation directly behind the car, and the line of sight was relatively small. And because the driver spends a lot of attention on the rearview mirror when driving, he also needs to observe the rearview mirror for a long time, which will cause the driver to be unable to concentrate on the road conditions ahead, resulting in more accidents. Later, people abandoned flat mirrors and replaced them with convex mirrors with a wider field of view.
Convex mirrors work by the fact that when parallel rays are projected onto the convex mirror, the reflected light diverges, which expands the field of view and allows better attention to the vehicle behind. More importantly, there is no need for the driver to look specifically at the convex mirror, and the afterlight from the corner of the eye can observe the situation behind.
Now, in order to continue to increase the viewing range of the rearview mirror on the basis of the convex mirror, and reduce the blind zone of the line of sight to a greater extent, a wide-angle lens is added to the rearview mirror. It's the little round one. It is generally installed above or below the outside of the rearview mirror, and the purpose is also to increase the viewing range and reduce the blind spot.
Is it important to reduce blind spots? According to statistics, traffic accidents caused by rearview mirror blind areas account for about 30% in China, and 70% of traffic accidents caused by highway lane changes are caused by rearview mirror blind spots, so the proportion of major accidents caused by them has reached 80%.
