Daniel A Neseth

20020154298, Oct 24, 2002

Apr 24, 2001

09/841527

John Hagen - Rochester MN, US
Daniel Neseth - Mantorville MN, US

INTERNATIONAL BUSINESS MACHINES CORPORATION - ARMONK NY

G01N021/88

356/239100

A glass disk is illuminated through an edge and an image of a segment of the disk edge is captured by a CCD camera. If internally reflected light is refracted and diffused by an anomaly in a disk edge, the anomaly will appear as a brilliant light spot on the image. Brilliant spots on a disk edge are detected as bright pixels; and within inspection zones, rows of pixels or areas of pixels are compared with a threshold value. Pixel strings having illumination intensity greater than the threshold are counted; and whenever the resulting count is larger than a predetermined number, the disk is rejected as having an anomaly of a size warranting rejection. In inspection area zones, pixel counts of intensities greater than a threshold value warrant rejection.

6356346, Mar 12, 2002

Jan 21, 2000

09/489342

John Patrick Hagen - Rochester MN
Daniel A. Neseth - Byron MN

International Business Machines Corporation - Armonk NY

G01N 2100

3562371, 3562375, 3562376, 25055901, 25055942

A device and associated method useful for determining whether a disk has a chipped edge. The preferred device includes a laser that radiates a laser beam to the disk in the vicinity of its edge. The preferred device also includes a radiation detector for detecting electromagnetic radiation from the laser after the radiation has been transmitted, reflected, retracted or scattered by the disk. A chip in the vicinity of the edge of the disk will direct the electromagnetic radiation differently than an intact disk edge. Therefore, the radiation detector can utilize changes in the detected electromagnetic radiation in order to determine whether the edge of the disk is intact or whether it has a defect, such as an edge chip.