What is an aspherical lens

The function of aspheric lens is to make the focus position formed by paraxial light and paraxial light coincide by modifying the curvature of lens surface.

At present, there are three main methods for manufacturing aspheric lenses:

1. Grinding aspheric lens: grinding directly on the whole glass, which is a relatively high manufacturing process cost;

2. Molded aspherical lens: it is made by directly pressing melted optical glass / optical resin with metal mold technology, and the manufacturing cost is relatively low;

3. Composite aspherical lens: cover a layer of special optical resin on the surface of the glass lens ground into a sphere, and then grind the optical resin part into an aspherical surface. The cost of this manufacturing process is between the above two processes.

Because the incident angle of light entering the wide-angle lens is relatively large, the performance of spherical aberration is particularly obvious in the wide-angle lens. Therefore, using aspherical lens on wide-angle lens is an effective method to eliminate aberration.

Usually, one side of aspheric lens is aspheric and the other side is spherical. In recent years, there have been double-sided aspheric lenses. Using such lenses can reduce the number of lenses and obtain a larger zoom lens.