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Proceedings Paper

Ultra-fast MTF Test for High-Volume production of CMOS Imaging Cameras
Author(s): Michael Dahl; Josef Heinisch; Stefan Krey; Stefan M.B. Bäumer; Johan Lurquin; Linghua Chen
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Paper Abstract

During the last years compact CMOS imaging cameras have grown into high volume applications such as mobile phones, PDAs, etc. In order to insure a constant quality of the lenses of the cameras, MTF is used as a figure of merit. MTF is a polychromatic, objective test for imaging lens quality including diffraction effects, system aberrations and surface defects as well. The draw back of MTF testing is that the proper measurement of the lens MTF is quite cumbersome and time consuming. In the current investigation we designed, produced and tested a new semi-automated MTF set up that is able to measure the polychromatic lens system MTF at 6 or more field points at best focus in less than 6 seconds. The computed MTF is a real diffraction MTF derived from a line spread function (not merely a contrast measurement). This enables lens manufacturers to perform 100% MTF testing even in high volume applications. Using statistic tools to analyze the data also gives possibility to find even small systematic errors in the production like shift or tilt of lenses and lens elements. Using this as feedback the quality of the product can be increased. The system is very compact and can be put easily in an assembly line. Besides design and test of the MTF set up correlation experiments between several testers have been carried out. A correlation of better than 6% points for all tested systems at all fields has been achieved.

Paper Details

Date Published: 22 December 2003
PDF: 8 pages
Proc. SPIE 5180, Optical Manufacturing and Testing V, (22 December 2003); doi: 10.1117/12.507928
Show Author Affiliations
Michael Dahl, TRIOPTICS GmbH (Germany)
Josef Heinisch, TRIOPTICS GmbH (Germany)
Stefan Krey, TRIOPTICS GmbH (Germany)
Stefan M.B. Bäumer, Philips Ctr. for Industrial Technology (Netherlands)
Johan Lurquin, Philips High-Tech Plastics (Netherlands)
Linghua Chen, Philips High-Tech Plastics (China)

Published in SPIE Proceedings Vol. 5180:
Optical Manufacturing and Testing V
H. Philip Stahl, Editor(s)

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