Nail clipper allows for removal of any excess nail that is jagged or has been missed. Nail clippers occasionally come with a pocket knife or a nail catcher; the multi-purpose nail clipper was invented by Hungarian inventor David Gestetner. The nail clipper consists of a head which may be concave or convex. Specialized nail clippers which have convex clipping ends are intended for trimming toenails, while concave clipping ends are for fingernails. The cutting head may be manufactured to be parallel or perpendicular to the principal axis of the cutter. Cutting heads which are parallel to the principal axis are made to
Telecentric lens (or "collimated") illuminators, which produce a parallel light flow, often from LED sources. An image-space (or image-side) telecentric lens produces images of the same size regardless of the distance between the lens and the film or image sensor. This allows the lens to be focused to different distances without changing the size of the image. Image-space telecentric lenses have an exit pupil infinitely far in front of the lens; that is, if one looks in the back of the lens, the image of the aperture is very far away. At the film or image sensor, all of the chief rays