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:
Sep. 23, 2003
Filed:
Apr. 28, 1997
Wayne Isami Imaino, San Jose, CA (US);
Anthony Juliana, Jr., San Jose, CA (US);
Milton Russell Latta, San Jose, CA (US);
Charles H. Lee, San Jose, CA (US);
Wai Cheung Leung, San Jose, CA (US);
Hal J. Rosen, Los Gatos, CA (US);
Steven Meeks, San Jose, CA (US);
Richard Sonningfeld, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A laser based inspection tool (LIT) for inspecting planar surfaces is described. In a preferred embodiment the LIT can simultaneously inspect both planar surfaces of disks for use in disk drives. In an embodiment of the invention, light reflected from the surface at an angle slightly offset from perpendicular is routed through a telecentric lens to a detector which converts the intensity of the reflected beam into an analog signal. The analog signal is sampled and digitized to generate pixel data. A data acquisition system sequentially stores the pixel data in a buffer. A median filter and derivative analysis can be applied to the pixel data to detect deviations indicating defects. An optional calibration system periodically reflects the scanning beam back to a detector to form a reference signal for use in absolute reflectivity measurements.