The achromatic lens is a kind of lens which is glued by two optical components: positive low refractive index (Corona) and negative high refractive index (flint). Compared with a single lens containing only a single piece of glass, the dual design of the dual lens can provide users with additional design freedom and further optimize the lens performance. Therefore, compared with the single lens with the same diameter and focal length, the achromatic lens has more obvious advantages.
The achromatic lens has various types of configurations, among which the common ones are positive achromatic lens, negative achromatic lens, triple achromatic lens and aspheric achromatic lens. It should be noted that the achromatic lens can be double (double element) or triple (three element), and the number of elements is independent of the number of rays corrected by the lens. In other words, the achromatic lens in double or triple configuration can correct red and blue light in the visible light range.
