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Proceedings Paper

Automated optical inspection technology for HDD head suspension
Author(s): Satoru Sakai; Hiroshi Oka; Moritoshi Ando
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Paper Abstract

We have developed an automated visual inspection technology for hard disk drive head suspensions. It consists of foreign materials detection technique and a precise, high-speed pattern width measurement. High S/N-ratio sensing is necessary for foreign materials detection. We developed a spectral sensing method that senses the reflection of two colors, blue and red, and calculates the reflection coefficients of the colors for every pixel. With this method, the S/N-ratio is enhanced by seven times. A high accuracy is required for measuring pattern widths. The problem is that this must be achieved within an inspection time of 0.4 s/suspension, which conventionally takes several seconds. To obtain a pattern signal at high speeds, suspensions are illuminated with transmitted light and their images are captured with a CCD line sensor. A sub-pixel method that calculates interstitial signal level enables both a high accuracy and high-speed measurement. An automated optical inspection system utilizing these technologies is currently operating in one of Fujitsu's factories. This paper describes this optical system, its measuring procedures, and the measured results of the system.

Paper Details

Date Published: 2 February 1998
PDF: 8 pages
Proc. SPIE 3306, Machine Vision Applications in Industrial Inspection VI, (2 February 1998); doi: 10.1117/12.301241
Show Author Affiliations
Satoru Sakai, Fujitsu Labs. Ltd. (Japan)
Hiroshi Oka, Fujitsu Labs. Ltd. (Japan)
Moritoshi Ando, Fujitsu Labs. Ltd. (Japan)


Published in SPIE Proceedings Vol. 3306:
Machine Vision Applications in Industrial Inspection VI
A. Ravishankar Rao; Ning S. Chang, Editor(s)

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