A Flatness Measurement Technique For Magnetic Recording Disks

D. L. Roberts

doi:10.1117/12.978153

1 August 1972 A Flatness Measurement Technique For Magnetic Recording Disks

D. L. Roberts

Proceedings Volume 0029, Imaging Techniques for Testing and Inspection; (1972) https://doi.org/10.1117/12.978153
Event: Imaging Techniques for Testing and Inspection, 1972, Los Angeles, United States

Abstract

An improved method of quickly determining the flatness characteristics of disks to be used for magnetic recording in disk packs has been developed. The data is obtained optically so that there is no mechanical contact with the disk. The instrument has been made relatively insensitive to disk alignment by means of a retro-reflector. The entire surface can be quickly scanned by a combined circular and radial motion of the disk holder. Scattering of the optical beam by scratches on the disk surface does not affect the accuracy of the system. The system compares the resultant image formed from the light beams reflected from the test disk surface with values expected from a disk within specifications. The process has been automated by scanning the output of the system with various size apertures located in front of a photodetectoi The final output pulses may be recorded as well as displayed. Portions of the disk surface that are out of specification can be rapidly located. This method of evaluation is considered more meaningful than present methods. The relative ease with which data may be taken is considered even more significant. Correlation with data taken by existing methods will be discussed.

Citation Download Citation

D. L. Roberts "A Flatness Measurement Technique For Magnetic Recording Disks", Proc. SPIE 0029, Imaging Techniques for Testing and Inspection, (1 August 1972); https://doi.org/10.1117/12.978153

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