Method of inspecting an edge of a glass disk for anomalies in an edge surface

The method of detecting defects in an edge of a glass disk substrate comprising the steps of:

• brightly illuminating said edge of said glass disk;
• determining an illumination level threshold representing a predetermined anomaly in said edge of said glass disk;
• determining a number of discrete locations within an inspection zone which shall constitute an anomaly sufficient to warrant rejection of said glass disk;
• detecting a level of illumination radiating from said edge of said glass disk;
• measuring said level of illumination radiating from said edge of said disk at discrete locations in an image of said edge of said glass disk;
• storing said measured level of illumination as a digital value for each of said discrete locations;
• designating an inspection zone within said image of said edge of said glass disk;
• determining a number of said compared digital values which equal or exceed said illumination level threshold within said inspection zone, which constitute a basis for rejecting said glass disk;
• selecting a plurality of said stored digital values associated with said designated inspection zone;
• comparing said stored digital values associated with said designated inspection zone with said previously determined radiating illumination threshold and determining the number of said compared digital values which equal or exceed said illumination level threshold, and
• determining as unacceptable any glass disk substrate having a number of said compared digital values which equal or exceed said illumination level threshold that equals or exceeds said determined number.

A method of inspecting edges of a glass disk substrate comprising the steps of:

• defining a threshold illumination intensity constituting an anomaly in said edge of said rotating glass disk;
• illuminating said disk through an edge of said disk;
• detecting refracted light passing outwardly through said edge;
• recording a digital image of said refracted light;
• quantifying a level of illumination intensity for each pixel of said digital image;
• establishing at least one inspection zone relative to said digital image;.
• defining an inspection criteria of fault counts for said at least one inspection zone;
• assigning a fault count to each pixel associated with said at least one inspection zone with a quantified level of illumination intensity greater than said defined threshold illumination intensity;
• comparing said fault count with said inspection criteria of fault counts for each said at least one inspection zone, and
• determining if said fault count exceeds said inspection criteria of fault counts.