OP2.2 Fresnel Lens
This is a method of making lenses thinner. Instead of having one thick lens, the lens is separated into a series of cuts. Each cut has the same radius of curvature as the original lens, but is located at the surface of the lens. This makes the lens thinner. The accuracy of the focal length has a greater error, but if accuracy is not very important, this is a good way to reduce the thickness of a lens.
Equipment Location: C61