Is a spherical lens spherical?
Concave lens can disperse light, that is, it plays a role of divergence. Therefore, concave lens is also called divergent lens. When the light parallel to the main optical axis passes through the concave lens, the reverse extension of these divergent rays will intersect a point on the main optical axis, manufacturer of spherical lens which is different from the focus of the convex lens. This point is not the convergence point of the actual light, so we call it the virtual focus, which is also represented by F.
The light incident from the virtual focus on one side of the concave lens is refracted and emitted parallel to the main light. In addition to spherical lens, there are aspherical lens, including cylindrical lens, annular surface lens, manufacturer of spherical lens etc. these lenses have more appropriate radius of curvature, can correct the aberration, and can bring better sharpness (also known as sharpness) and better resolution. Aspherical lens is also a trend of current research.
