Timothy A. Potts, Dark Field Technologies Inc., Shelton, CT
The need to maximize coater yields in optical glass and large format coated glass is of paramount importance. Low-e, smartglass and coated optical glass are very high value-added and must be defect-free.
As 30% - 70% of all coating defects are due to unclean first surfaces, improving first surface cleanliness is the assured means to increase coater yield. However, there have been no simple means to measure first surface cleanliness, on-line, real-time, 100%. Glass washer and cleaner vendors do not provide this first surface cleanliness measurement, and conventional camera and laser systems are incapable of performing this feat. In addition, these conventional systems are plagued by false hits and constant alignment problems.
A new generation of Solid-State Laser Reflection (SSLR) scanners has been developed and proven for both optical glass and large format coated glass inspection; 1µm defects and “invisible” residue are easily detected. These in-line 100% automatic glass cleanliness measurement systems deliver a host of benefits including increased yield, scrap reduction, reduced labor cost and maximum customer satisfaction. In addition, SSLR technology is self-aligning, solving the problems associated with all conventional inspection technologies.
System theory will be explained and application examples will be presented.