Lens array manufacturing using a driven diamond tool on an ultra precision lathe

The integration of a high spced spindic onto an Ultra Precision (UP) lathe gives the ability to manufacture aspheric lens arrays with high form accuracy, bw roughness and a precise pitch control in diamond machinable metal alloys, crystals and plastic substrates. The machine kinematics of the precision lathe with two linear and one rotary axis has a major impact 011 the NC-code generation and the tool setting process. The present paper illustrates the general set-up and the tool path generation in detail. The achieved form accuracy and surface roughness of the lens arrays are shown and discussed

Ultra-precise optical mirrors with thick amorphous silicon layer

Metal mirrors with excellent optical, mechanical and thermal properties are used for a wide range of modern optical applications like telescopes, spectrometers or scanners. The surface quality of machined optical surfaces is one of the limiting factors in the manufacturing of ultra-precise optical components. Substrate materials like silicon can be polished very well and very smooth surfaces can be obtained. However, crystalline silicon is very hard and causes a large tool wear which makes the ultra-precise machining of silicon substrates difficult and expensive. Ductile substrate materials like Al, Cu of AlSi-alloys are much easier to machine, however, they cannot be polished to very low surface roughness. For reflective optics the state of the art is to overcome these limitations by deposition of electrochemical nickel-phosphorus (NiP) onto a machined substrate. The NiP layer can be polished much better than the diamond machined surface. A roughness below 1 nm rms can be achieved. This paper discusses a new technology which is based on a amorphous silicon layer with a thickness of several microns deposited onto the surface. First results of diamond turned samples with polished surfaces are shown. This thick amorphous silicon layer can subsequently be polished and very smooth surfaces can be achieved