Improved AR coating reflection color uniformity and stability using multiple anodes and fuzzy logic control in DC reactive sputter coating

Abstract

ABSTRACT DC reactive magnetron sputter techniques have been developed for the application of antireflection (AR) coatings to plastic ophthalmic lenses. The met hod described here uses the Deposition Sciences Inc. (DSI) Microdyn TM process in which the lenses are mounted on a spinning drum adjacent to two 40” long planar magnetron cathodes. Improvement in deposition uniformity along the length of the cathodes was accomplished by th e use of multiple active anodes. Improvement in run to run stability was accomplished by use of fuzzy logic control techniques. Details of this Multiple-Anode Fuzzy-Logic (MAFL) process will be discussed in relation to the significant improvement in control of reflectance color of anti-reflection coated eyeglass lenses. For a specific anti-reflection coating, control of color coordinate a* was improved by a factor of 2.5 and b* by a factor of 5.0 Keywords : antireflection coatings, color control, magnetron sputter, multiple anodes, fuzzy logic, process control, DC reactive sputt er, ophthalmic coatings, AR 1. Introduction SOLA Optical USA (now a part of Carl Zeiss Vision Gmbh) is the largest manufacturer of spectacle lenses in North America and SOLA International is among the largest in the world. In its 45-year history, SOLA has manufactured well over 2 billion lenses and today sells approximately 110 million lenses annually. SOLA Optical USA purchased two Deposition Sciences Inc. (DSI) Microdyn