Doublets Lenses

Doublets lenses Achromatic lens is composed of convex and concave lenses made of two glasses with different optical properties. Coronal glass with small refractive index and large dispersion ability is often used to make convex lens, and flint glass with large refractive index and small dispersion ability is used to make concave lens. Achromatic lens can only overlap the image points of the two main color lights (see Figure), so as to eliminate the color difference of the two color lights.

Two piece achromatic lens is one of the simplest achromatic lenses. It can be divided into two types: Double gluing and double separation. Of course, achromatic lens can also be composed of multi chip lens, which depends on its use needs. Achromatic lenses with large aperture are usually separated. They are assembled in the frame and have excellent comprehensive performance. For the double split lens, the gap between the two lenses is actually equivalent to the third lens, which can better eliminate the color difference than the glued lens. Therefore, it can balance the aberration in a wide range of wave bands and play a role in the field of broadband imaging.