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The single point diamond turning process is ideally suited to making aspheric optical elements for use in the infrared region.In this paper, applications of diamond turning to various materials and geometries for both refractive and reflective optical elements are considered, based upon direct manufacturing experience.

Aspheric surface generation and precision machining have been important technologies at Hughes Optical Products, Inc. (formerly Optical Division, Bell & Howell Company) for over twenty years. Present machining capabilities and supporting services which are available on a custom basis are described. A variety of applications of diamond machining are illustrated, involving not only the usual reflective materials such as aluminum, copper, and electroless nickel but also such IR refractive materials as germanium, silicon, and chalcogenide glasses.

The U. S. Army's new M19 binocular. which incorporates an unusual modular assembly concept for simplified maintainability, is currently being produced at the rate of 2,000 per month.In this paper, the origin and development by the Army of the modular concept for this binocular are reviewed briefly and performance requirements are summarized. Following this, the manufacturing engineering approach and implementation developed and carried out by the Optics Division of Bell & Howell Company in producing the M -19 binocular are presented. GENESIS OF THE M19 BINOCULARDuring the second World war, the U. S. Armed Forces invested heavily in the purchase of binoculars. Unofficial surveys indicate that over 400,000 6 X 30 and 7 X 50 instruments were purchased from mobilization suppliers. These binoculars were primarily adaptations of commercially available instruments, with only minor changes, such as the addition of a reticle, made to address military utilization. The rapid expansion of binocular inventories ceased at the end of the war and only a few thousand new instruments were since purchased.The Korean conflict witnessed the utilization of World War II instruments.Four major issues were raised by wartime experience; they were: weight, size, mechanical reliability, and maintainability. Improvements were made to enhance the watertightness of the three primary binocular models but studies, conducted in 1955, concluded that no major reduction in size or weight was possible within the existing configure ion.Therefore, in 1956, the U. S. Army authorized the development of the T14 Binocular . The program objective was, and we quote, to "redesign the standard 7 X 50 M17 Binocular and reduce its weight and bulk without impairing performance." This simple statement initiated the development of the present, sophisticated M19 binocular.It was recognized from the beginning that the stated design goals did not address two of the more glaring problems, namely reliability and maintenance.The two most prevalent reliability failure areas were sealing integrity and interpupillary hinge wear. The maintenance problem had its basis in the quantity of individual spare parts, approximately 250, and special tools, approximately 125.The concern for a design more compatible with maintenance was further spurred by the facilities and personnel concerns and the fact that a binocular failure effectively removed the instrument from use for a period of three to six months.Three alternatives were, therefore, subjected to both technical and financial analysis.They were:a.Design a new binocular which required piece part maintenance but which met the size and bulk dictates and incorporated greater ruggedness and sealing capability.b.Design a totally new binocular which could be economically discarded at failure. Reliability would be traded -off against cost to provide optimum financial return. Such a unit could be very effectively sealed after assembly and adjustment.c.Design a totally new binocular which would be maintainable with the absolute minimum n...