The main features of the crescent lens are: one side is convex and one side is concave. It can be either a converging lens or a divergent lens; determined by the refractive index, curvature, and radius.

The main feature is that the focal length is positive, one side is a plane, and one side is a convex surface

A concave lens is composed of a plane and a concave sphere that can produce a negative spherical difference, which is often used in the system to expand the light beam or increase the focal length to balance the deviation of other lenses.

It does not change the magnification of the system. A protection window usually used in electronic sensors or external environments

It is often used for beam reflection, refraction, and deflection of images. The rectangular prism itself has a large contact area and has 45° and 90°.

Zinc sulfide (ZnS) is divided into two materials, a white multispectral material, a yellow native material, is a chemically inert material, with high purity

Zinc sulfide (ZnS) is divided into two materials, a white multispectral material, a yellow native material, is a chemically inert material, with high purity

The double-convex lens features a positive focal length consisting of two convex surfaces with equal radii; commonly used for imaging relay systems and for imaging objects at a limited conjugate distance

Double-concave lens is composed of two concave surfaces with equal side radius of curvature, which is often used for lens beam expansion, projection, and expanding the focal length of the optical system.

Two planes have angles; two non-parallel planes can avoid the interference effect (Etalon effect) reflected by the front and rear surfaces of the high parallelism window