Title: In-situ scanning white light interferometry employing dual-sensing configuration and active fringe-locking strategy

Authors: Liang-Chia Chen; Sheng-Lih Yeh; Abraham Mario Tapilouw; Kun-Feng Lee

Addresses: Graduate Institute of Automation Technology, National Taipei University of Technology, Sec. 3, Chung-Hsiao E. Rd., Taipei, 106, Taiwan. ' Department of Mechanical Engineering, Lunghwa University of Science and Technology, No. 300, Sec.1,Wanshou Rd., Guishan Shiang, Taoyuan County, 333, Taiwan. ' Graduate Institute of Automation Technology, National Taipei University of Technology, Sec. 3, Chung-Hsiao E. Rd., Taipei, 106, Taiwan. ' Graduate Institute of Automation Technology, National Taipei University of Technology, Sec. 3, Chung-Hsiao E. Rd., Taipei, 106, Taiwan

Abstract: This article presents new white light interferometry with vibration-resistant capability achieved by in-situ optical detection and closed-loop feedback strategies. Scanning white light interferometry (SWLI) has become a popular measurement method due to its long measurement range and high measurement accuracy. However, the drawback of in-situ interferometry lies mainly in unacceptable measurement errors caused by environmental disturbance such as mechanical vibration and acoustic noise. This paper describes a method employing dual-sensing configuration and active fringe-locking strategy to overcome the issue. A specially designed band-pass filter is employed to generate a high-coherent light field for real-time detecting vibratory displacement. As proven by the experimental results, the maximum measurement error caused by vibration can be effectively reduced by more than six folds.

Keywords: in-situ measurement; scanning white light interferometry; SWLI; vibration resistance; automatic optical inspection; AOI; fringe locking; dual sensing.

DOI: 10.1504/IJNM.2012.044654

International Journal of Nanomanufacturing, 2012 Vol.8 No.1/2, pp.40 - 53

Available online: 01 Jan 2012 *

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