The measurement of aspheric or spherical lenses used in HDTV screens, head-up displays for fighter aircraft, photocopiers and LCD screens causes a substantial problem for glass manufacturers. This is mainly because of the large component size which is typically greater than 300mm. Also, the 150mm range necessary to measure the whole surface of a lens is very large in relation to the 100 Nanometre resolution required.

PPE Ltd, a subsidiary of the French company, Thomson CSF, is already an existing customer of Taylor Hobson having purchased Diamond-Turning Machines for the manufacture of lenses and Form Talysurf Series 2 (FTSS2) Instruments for inspecting the quality of current products. However, the FTSS2 does not have the gauge range to measure the form of PPE's large aspherical lenses. Therefore, Taylor Hobson's Special Applications Department proposed a dedicated instrument capable of meeting PPE's high precision specification.

The unique new inspection system is currently capable of measuring the profile and form of Ø300mm component and has a 165mm gauge range with a resolution of 10 Nanometres!

A spokesman from Pilkington said: 'We carried out an in-depth search of the market but could not find anything that was capable of measuring large aspherical lenses to the accuracy we required. So we approached Taylor Hobson Precision and worked together to develop an instrument that has allowed us to improve our production techniques and remain at the forefront of our industry'.

For more information contact Taylor Hobson Precision and request the "Large Diameter Aspherics Application Report".