3D metrology improves from accuracy of diffractive optics

Leicester, England and Keene, NH--Two established manufacturers of precision optical measurement and manufacturing equipment—Taylor Hobson and Precitech—have combined their expertise to develop a new process to measure, analyze, and correct for diffractive-optics form errors in three dimensions. This latest advance in 3D metrology and correction of aspheric diffractive optics will be unveiled at the 26th Annual Meeting of the American Society of Precision Engineering (November 14, 2011; Denver, CO).

Previously it was not possible to measure diffractive optical surfaces and correct for symmetric and asymmetric errors inherent in the diamond-turning process, because large diffractive zones within the optics made it difficult to measure shape. The new process uses a Talysurf PGI Optics 3D metrology instrument with advanced aspherics-analysis software and a Talysurf CCI noncontact 3D optical profiler from Taylor Hobson, along with a NanoForm 250Ultra ultraprecision machine tool with a rotary B axis and a fast tool servo from Precitech.

Presentation of the new process will be made by Joffery Roblee, director of product engineering at Precitech and an active member of the European Society of Precision Engineering and Nanotechnology and the American Society of Precision Engineering; and by Erik Stover, business development manager for Taylor Hobson. Copies of the presentation will be released following the meeting.

Roblee, who joined Precitech in 2002, holds a number of patents and awards and has presented numerous papers on temperature control, machine dynamics, air-bearing design, optics fabrication, and optomechanics. Stover joined Taylor Hobson in 2010 and has an extensive background in optical manufacturing and process engineering.

Precitech makes ultraprecision single-point and multiaxis diamond-turning machines for applications requiring nanometric levels of accuracy. Its NanoForm 250Ultra precision diamond-turning lathe is designed for the production of optical lenses, optical-mold inserts, mirrors, and precision mechanical components. It has a 16 pm feedback resolution and 0.01 nm programming resolution. Taylor Hobson makes ultraprecision measurement instrumentation for a variety of markets, including optics, semiconductors, hard disk drives and nanotechnology research. Its Talysurf PGI Optics 3D profiler does 3D form measurement of shallow- and steep-sided molds and lenses (up to 85°), and (along with its software) performs diffractive-lens measurement and analysis. Its Talysurf CCI 3D noncontact optical profiler provides surface texture, step height, and microdimensional measurement on rough, smooth, and reflective surfaces.