The design of car rearview mirrors is mainly based on the principle of light reflection. The flat mirror section provides a true-scale reflected image, while the convex mirror portion expands the field of view through its outwardly curved surface, making objects appear closer than their actual distance, though the resulting image is actually a diminished virtual image. For instance, the right rearview mirror typically has a curvature radius of 800 to 1200 millimeters, while the left mirror ranges from 1500 to 2000 millimeters, achieving a balance between field of view and distance perception. Some premium models additionally incorporate electrochromic anti-glare technology or digital camera systems to enhance nighttime safety or overcome the physical constraints of conventional mirrors. Notably, rearview mirror reflectivity must comply with the industry standard of at least 40% to ensure image clarity, and the "magnifying" effect of convex mirrors is fundamentally an optical illusion created by light divergence that widens the viewing angle.
