Coating Micro Optics

June 18, 2013


As consumer electronics continue to shrink in size and increase in functionality so too will the optics used to power and enable the displays and optoelectronics utilized in these devices. With that being said the need for custom precision thin-film coated micro optics has never been greater. The addition of a thin-film coating to a micro optic could make the difference between an onboard camera application being success or failure due to the coating’s ability to increase light transmission and decrease reflectance both indoors and out.

Micro optics are typically created from injection molded polymers. Currently Zeonex E48R is widely used along with polycarbonate and in some cases acrylic or PMMA. Plastics create a specific set of challenges for thin-film coaters due to their heat constraints as well as their delicate nature which somewhat limit process handling. North American Coating Laboratories specializes in processing multiple types of traditional and exotic plastics. Our coating processes typically are not performed much warmer than room temperature making our coating solutions ideal for sophisticated and heat-sensitive polymers.

The biggest challenge in depositing thin-film coatings on micro optics is the minimal size of the optic (a micro optic is typically defined as an optic measuring ≤12.0mm) which makes handling both pre and post coating very challenging. Because micro optics have such a small “active” area creating fixtures that make minimal yet secure contact to the optic while in process is difficult. When processing optics of a typical (size 2” or greater) the tolerance for holding the substrate during coating is substantially greater (2-3mm all along the outer diameter of the substrate) in a micro optical application the substrates themselves may be smaller than 3mm in total.

The second significant challenge that micro optics manufacturers and coating service providers face is packaging for transportation of micro optics. Because of their minimal size traditional optics packaging methods are not applicable to micro optics. In a standard optical substrate program; packaging for transportation is usually limited to acid free tissue, polyethylene bags, and non-tackified film wrap. Micro optics require custom solutions which consist of thermo-formed trays or specially designed closed cell foam packaging.

Because tooling and packaging create challenges in the manufacture of micro optics many optics manufacturers and coating service providers are now collaborating on ship and coat type fixtures which travel between facilities and serve as an “all in one” housing for the optic. This basically means that the fixture containing the optic is shipped and coated in the same housing which reduces handling and spoilage. Additionally this approach can maximize the usable space in a coating chamber making depositions more efficient for both the coating service provider and the optics manufacturer.

North American Coating Laboratories has provided anti-reflective and has worked with anti-glare coated substrates for 38 years. In all cases we can work closely with you to help determine exactly which solution will be best suited for your program.

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