TechTalk July/August 2016

By Staff

The Right Combination in the Coating Package

The performance and durability of an ophthalmic lens is largely determined by the coating package. Satisloh offers a wide variety of durable hard coatings, innovative AR coatings, and state-of-the-art top coating solutions as well as a range of coating machines that meet the needs of every production environment. The right combination of these components, matched to both the lens material and the customer’s requirements, achieves highest wearer satisfaction.

The current demand for AR lenses emphasizes the importance of hard coating, the foundation for supporting AR coatings. Match your AR coating process with an appropriate hard coating style and process. If you’re using a premium AR coating, match it with an equally high-quality hard coating. Using an inexpensive hard coating negates the quality level of your premium AR and doesn’t save money in the long run because consumers get a less desirable product and may end up dissatisfied with their purchase.

Satisloh's MC-280-X coating system is for labs that need big technology but have limited space. Based on their bigger MC-380-X, the MC-280-X combines multiple process applications with small batch capabilities for the highest flexibility. The MC-280-X delivers the highest quality AR coatings in small batches. Using the same sophisticated AR and mirror coating processes as Satisloh’s big box coaters, the MC-280-X guarantees the best results.

The trend in AR coatings is the reduction of UV light reflecting back into the eyes, and the need to block blue light from today’s portable electronics and desk top computers. These coatings are in high demand, along with high scratch resistance and anti-static properties. Brian Peterson, director, coating technologies and micro-lab projects, Satisloh

 

Back to the Basics of AR

With all the new demands on AR coatings, such as UV and blue light protection, or just a super hydrophobic on a basic anti-reflection (AR) coating, one cannot lose sight of the basics. There are multiple variables to account for in order to produce an AR coating that will withstand or exceed the customer’s warranty period.

One of the most important variables in order to produce a robust AR coating is material. Not only the types of lens materials such as CR-39, Poly, Trivex, etc., but more importantly the hard coat (HC) applied to the substrate. Whether the lens has a thermally cured or UV cured hard coat (in some cases both), the AR coating has to be able to perform on that particular HC. If the HC is not applied properly, the AR coating wrongly takes the blame for the failure of the end product. This is how AR gets a bad reputation. If the HC is not consistent—including thickness, cure times, and age of lacquers—the quality of the AR will also change. The AR should be designed to perform on a properly applied HC, and the HC needs to be kept consistent.

Even if the lens has a properly applied HC, the lens has to be correctly prepared and handled before applying the AR coating—in most cases, processed through an ultrasonic cleaner with soap and/or caustic solutions maintained at proper concentrations; followed by a degassing oven, and finally with an ion source etch inside the coating chamber itself.

Someone may have the best designed AR coating for a specific application, and this function may work flawlessly. However, if the basics are not followed the coating will
fail every time. Josh Chandonnet, coating services manager, North America Schneider Optical Machines


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May/June LabTalk 2017