Abstract: There is disclosed an optical unit which is primarily intended to provide visual references for measuring machines such as coordinate measuring machines, milling machines, EDM machines, tape and computer controlled drilling machines, etc. The optical unit has a motor driven zoom lens within a lens housing, and an optical coupling for a video camera. The zoom lens assembly of this invention is a modification of that shown in U.S. Pat. No. 4,884,878 to include a stepper drive motor and a rotational position encoder which provides the necessary lens information to determine the power of magnification of the lens at any instant position. The preferred encoder includes a disc mounted on the barrel of the zoom lens which has a plurality of slots about its periphery at equal angular increments, and a photo-optical sensor which counts light pulses and generates a pulsed electrical signal as the disc rotates beside the sensor.

Abstract: There is disclosed an optical unit which is primarily intended to retrofit existing work piece processing machines such as coordinate measuring machines, milling machines or EDM machines. The optical unit includes a zoom lens with a lens housing, and an optical coupling for a video camera. The lens housing isolates the optical elements against vibration during adjustment of the zoom lens, and for this purpose a flexible belt link is provided between a lens focusing knob and the zoom lens. An optical coupling having a relay or copying lens and an extender lens is included between the video camera and the zoom lens. This coupling effectively decrease the back focal length of the high magnification zoom lens and greatly compress the overall assembly. The optical coupling includes a coupling housing having a focusing cylinder that rotatably adjusts the position of the relay lens.

Abstract: An objective lens system having a pair of plano-convex lenses disposed adjacent each other with the convex surfaces facing each other and aligned along common optical axis. A plurality of optical fibers surround the plan-convex lenses to convey light and illuminate an object to be viewed by the objective lens assembly. Adjustably positioned adjacent the second plano-convex lens is a field lens system including an elongate rod lens for conducting the intermediate image from the plano-convex lenses and to relay it to an ocular lens system for viewing by the user.