The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 02, 1999
Filed:
Jun. 26, 1998
Peter C Jann, Santa Clara, CA (US);
Marco A Krumbuegel, Danville, CA (US);
Reginald Lee, Alameda, CA (US);
Ming M Yang, San Jose, CA (US);
HMT Technology Corporation, Fremont, CA (US);
Abstract
An apparatus for measuring the height and diameter of laser-zone texture bumps on a rigid magnetic disk substrate is disclosed. The apparatus has a disk holder for supporting and rotating the substrate, and an optical beam-source assembly for directing a focused laser beam on the substrate, and for shifting the position of the beam's illumination spot on the substrate in a tracking (radial) direction. An optical detection assembly in the apparatus measures the deflection of the laser beam due to specular reflection of the beam by laser-zone texture bumps, as a function of time, in both scanning (circumferential) and tracking directions. A computational device in the apparatus functions to (i) calculate scanning and tracking deflection values which characterize beam deflections in the scanning and tracking directions, respectively, for a texture bump passing through the illumination spot produced by the beam on the substrate, (ii) select for bump-height analysis, those texture bumps whose scanning deflection values are above a selected threshold value and whose tracking deflection values are below a selected threshold value, indicative of a condition in which the selected textured bumps are each in focus and centered within said illumination spot, and (iii) determine the texture bump heights and diameters of the selected bumps from the beam deflections in the scanning direction. Also disclosed is a method by which the apparatus measures the light power which is scattered by the of laser-zone texture bumps on a rigid magnetic disk substrate.