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Proceedings Paper

The ultrahigh precision form measurement of small, steep-sided aspheric moulds, incorporating novel hardware and software developments
Author(s): M. W. Mills; Matthew J. Hutchinson
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Paper Abstract

A variety of consumer applications, eg cellphone camera lenses, optical storage devices, digital cameras, etc, are driving the demand for small, high aspheric departure rotationally-symmetric moulded optics, manufactured both in polymer and glass materials. The mould tools for such components are manufactured by ultra-high precision techniques such as single point diamond turning and ultra-precision grinding, and must be accurate to <1/10μm levels for form, and exhibit nanometric surface finish quality. The aspheric forms of such components’ optical surfaces exhibit high departure from best-fit sphere towards their outer edge, which renders this outer region especially critical for optical performance. The high slope of these components at the clear aperture has caused some restrictions on the use of profilometry in the measurement of form across their full diameter. Taylor Hobson designs and manufactures a range of ultra-precision profilometers for use in such industries as aspheric optics fabrication. In order to address the issues described, a new measurement system, Taylor Hobson Form Talysurf PGI 1250, has been developed, which contains new Aspheric Data Fusion Software, as well as Asphero-Diffractive Analysis Software, allowing the entire diametric profile to be analysed to the desired level of accuracy. This development removes the previous limitation of maximum slope for this type of measurement, thus enabling better quality control of high slope, high aspheric departure optics. Measurement data from the Form Talysurf PGI 1250 can be fed back directly to the machine tool, in order to optimize the form of the optical mould.

Paper Details

Date Published: 2 May 2005
PDF: 4 pages
Proc. SPIE 10315, Optifab 2005: Technical Digest, 103150O (2 May 2005); doi: 10.1117/12.612038
Show Author Affiliations
M. W. Mills, Taylor Hobson Ltd. (United Kingdom)
Matthew J. Hutchinson, Taylor Hobson Ltd. (United Kingdom)

Published in SPIE Proceedings Vol. 10315:
Optifab 2005: Technical Digest
Robert E. Fischer; Masahide Katsuki; Matthias Pfaff; Kathleen A. Richardson, Editor(s)

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