Fresnel lenses are designed to divide

The focus is on the other side of the light.By design

1,1 positive Fresnel lens:

The light comes in from one side, and it's a finite conjugate, the focus and the light are on the same side, and it's used as the first reflective surface,

Fresnel beam separator and Fresnel prism.

2,2 minus Fresnel lens:

A Fresnel optical lens is the opposite of a positive focusing Fresnel lens, which comes out on the other side and focuses to a point or is emitted as parallel light. The surface is usually coated.

Such lenses are usually designed as colorimetric lenses (for example, Fresnel lenses for projection,

structurally

Circular Fresnel lens

Fresnel lens array.

Fresnel lens applications

Fresnel lens applications

Columnar Fresnel lens,

Linear Fresnel lens.

Diffraction Fresnel lens,

Fresnel reflecting lens (magnifying lens) and concentrating lens (e.g. the sun can concentrate light and heat with Fresnel lens).