Therefore, it is called "single lens" optical lens.With the development of science and technology, in the early days, cameras were only equipped with a convex lens lens optical lens, while modern lenses have a number of convex and concave lenses of different forms and functions to form a convergent lens. Therefore, it is the main raw material for lens production.

2.Crown glass - an optical lens made by adding sodium oxide and calcium oxide to the glass.

Optical glass has high transparency, purity, colorless, uniform optical lens with good refractive ability, thin lens -- a lens whose thickness in the central part is large compared to the radius of curvature on both sides.Due to the different chemical composition and refractive index of optical glass are:

1.Flint glass - an optical lens made of lead oxide added to the glass.To increase the refractive index (1, called a "compound lens" optical lens, to reduce its refractive index (ba-coronal glass has an index of 1.7055).

3.Lanthanum coronal glass -- a type of optical lens found with high refractive index and low dispersion rate.A concave lens in a compound lens ACTS as an optical lens correcting aberrations.