Video high-density disk surface testing with a laser diode and a position sensor

A surface tester was developed for the VHD (video high-density disk) using an optical technique. A 10-microm diam beam from a laser diode irradiates the disk surface, and a photosensor detects the angle and the intensity of a reflected beam. Defects on the surface are found by observing changes in t...

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Bibliographic Details
Published inApplied optics (2004) Vol. 27; no. 22; p. 4615
Main Authors Ono, A, Sasaki, K, Komatsu, T
Format Journal Article
LanguageEnglish
Published United States 15.11.1988
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Summary:A surface tester was developed for the VHD (video high-density disk) using an optical technique. A 10-microm diam beam from a laser diode irradiates the disk surface, and a photosensor detects the angle and the intensity of a reflected beam. Defects on the surface are found by observing changes in the photosensor signal. A microscopic examination of the disk surface revealed that the tester can detect defects larger than 10 microm. The tester classifies defects by their category and size and displays a defect map on a monitor screen. The data obtained are utilized for improving the VHD manufacturing process.
ISSN:1559-128X
DOI:10.1364/AO.27.004615