Difference Between Aspherical Lens and Glass Lenses

Glass Lenses:

It is composed of a converging lens and a diverging lens. The converging lens is a convex lens and the diverging lens is a concave lens. The reason is that a convex lens or a concave lens always has a spherical surface, so the lens with a spherical surface is called a "spherical lens".


Because the lens of the spherical lens has a single curvature radius, the processing is simple and the price is cheap. However, due to the characteristics brought by a single curvature, various spherical aberrations, chromatic aberrations and other aberrations will occur, such as unclear images, peripheral deformation of the visual object, halos and other problems. Especially for long focal length and large diameter lenses, various aberrations are particularly serious.


To fundamentally solve these problems, precise and accurate aspherical lenses were born.


Aspherical Lens:

The lens used is an aspherical lens, which means that the surface shape of the lens may be a quadratic or cubic curved surface, of which the cubic curved surface is also called a free-form surface.


The lens shape of an aspherical lens is accurately calculated and ground by a precision machine. The above correction factors are fully taken into consideration during the design process. Therefore, one aspherical lens can achieve the effect of correcting aberrations of multiple spherical lenses. Using aspherical lenses Lenses made with spherical lenses can effectively reduce the number of lenses and thus reduce the size of the lens. It also makes the lens have better imaging accuracy, better light transmittance, and more accurate color reproduction.


The main feature is that it can improve the refractive index of light at the edge of the lens and make the focus of the lens more focused, thereby making the imaging of objects more detailed. Compared with using a spherical lens, it can also improve the light transmittance, reduce the impact of various aberrations, and eliminate some problems such as unclear images and peripheral distortion of the visual object.

The picture shows a comparison example of a spherical lens and an aspheric lens
(Pictures are for example reference only)