Grin Lens

Grin Lens is made of special glass material which make use of the continuous changed by radial of the refractive index, the working theory may be explained: An incoming light ray is first refracted along the high refractive index side, the refractive index of the lens center is highest, and refractive index (n) continuatively changed low with radial distance of lens. 
Grin Lens is an optical lens which use for optics collimation, optics focus and optical image transmission etc for this kind of characteristic. The application of Grin Lens’ is the same as conventional lens, performance of the lens depends on a continuous change of the refractive index within the lens material, The simple geometry allows us a very cost-effective production and simplifies the assembly of product essentially, just polish the two end surface and control the length, instead of complicated shaped surfaces plane optical surfaces are used for the conventional lens
Since limited for the special assembly and working theory, the diameter of conventional lens is not very small, for example: less than 1.0mm, at same time, it can’t get the image in very close working distance, such as: in 5.0mm distance, However, the Grin Lens are fabricated down to 1.0mm in diameter and get the image in zero distance.