Ultra-precision molded polymer optics range from high precision imaging objectives to tiny lenses like those used in camera modules for cell phones, where centration tolerances and filling of small features is a challenge. We propose a manufacturing process termed Compression Molded Polymer Aspheres (COMPAS). Polymer preforms are inserted into mold cavities, and isothermally heated above glass point. Novel tooling has been developed to produce high volumes of COMPAS optics at reasonable cost and cycle time, using large scale parallelization of mold cavities. First results of the COMPAS process are very encouraging: shape accuracy (<500 nm peak-to-valley), surface centration (<5 μm), and birefringence (<20 nm/cm) are well below values typically measured for injection molded lenses. COMPAS lenses are also gate free. We describe details of the on-axis turning of arrays and multi-cavities (DPI) and the COMPAS precision polymer molding process. We describe the metaphysical background of disruptive engineering based on physical principles, which is the reason behind developing DPI and COMPAS.
One lens at a time on axis diamond turning or grinding of lens arrays with a large number of lenses is conventionally impractical because of the difficulties to shift and balance the substrate for each lens position. A novel method for automatic indexing was developed. This method uses an innovative mechatronics tooling (patent pending) that allows dynamic indexing at constant work spindle speed for maximum productivity and thermal stability of the work spindle while the balancing condition is maintained. In this paper we shall compare the machining capabilities of this method to free-form machining techniques, discuss about the main issues, present the concept and design of the working prototype and specific test bed, and present the results of the first cutting tests.
The JWST Mid-Infrared Instrument (MIRI) is designed to meet the JWST science requirements for mid-IR capabilities
and includes an Imager MIRIM provided by CEA (France). A double-prism assembly (DPA) allows MIRIM to perform
low-resolution spectroscopy. The MIRIM DPA shall meet a number of challenging requirements in terms of optical and
mechanical constraints, especially severe optical tolerances, limited envelope and very high vibration loads.
The University of Cologne (Germany) and the Centre Spatial de Liege (Belgium) are responsible for design,
manufacturing, integration, and testing of the prism assembly. A companion paper (Fischer et al. 2008) is presenting the
science drivers and mechanical design of the DPA, while this paper is focusing on optical manufacturing and overall
The first part of this paper describes the manufacturing of Zinc-sulphide and Germanium prisms and techniques to ensure
an accurate positioning of the prisms in their holder. (1) The delicate manufacturing of Ge and ZnS materials and (2) the
severe specifications on the bearing and optical surfaces flatness and the tolerance on the prism optical angles make this
process innovating. The specifications verification is carried out using mechanical and optical measurements; the
implemented techniques are described in this paper.
The second part concerns the qualification program of the double-prism assembly, including the prisms, the holder and
the prisms anti-reflective coatings qualification. Both predictions and actual test results are shown.