What is the purpose of the vertical line on a car's rearview mirror?
1 Answers
The vertical line on a car's rearview mirror serves as a boundary to differentiate the mirror surfaces. It is known as a "dual-curvature rearview mirror," designed to observe closer areas on the side of the vehicle. The combination of two curvatures helps minimize blind spots in the rearview mirror. More detailed explanations are as follows: 1. A car's rearview mirror acts as the driver's "second eye." Its primary function is to expand the driver's field of vision, reduce blind spots, and enhance driving safety. Whether turning, exiting, or reversing, carefully checking the rearview mirror is essential—neglecting it is an extremely dangerous driving behavior. 2. The purpose of the vertical line on the rearview mirror: 1) This line exists because the mirror uses a dual-curvature lens, meaning one lens with two curvatures. Based on factors such as the vehicle model, the driver's eye position relative to the rearview mirror, and visibility requirements, optical principles and data methods are applied to select different curvature radii for various viewing angles (front, rear, left, and right), ensuring a smooth transition. The inner two-thirds of the mirror (closer to the driver's cabin) uses a standard flat mirror, while the outer one-third uses a convex mirror. The black line in the middle separates these sections, helping the driver see behind more clearly. 2) The area inside the dotted line provides a normal field of view for observing nearby conditions. Due to its higher curvature, it offers a clearer view of close-range situations, such as seeing the rear wheels and adjacent vehicles while reversing. During regular use, the combination of two curvatures balances near and far visibility, effectively reducing blind spots, improving convenience, and lowering risks. This design serves a similar purpose to small convex mirrors attached to rearview mirrors.
