Touch screens have become prevalent interfaces on smartphones, tablets, laptop computers and automotive electronic in-dash displays. Touch screen controls are also widely used on point-of-sale devices, manufacturing machinery displays and other industrial applications. Regardless of the application, touch screen products must deliver touch sensitivity in a durable, scratch- and impact-resistant surface that protects the electronics inside.

Carestream provides precision coating services for hardcoat films used in display, electronics, optical and graphics applications. A hardcoat film construction consists of a substrate film and hardcoat layer. The substrate film can be of polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene naphthalate (PEN) or cyclic olefin polymer (COP). The hardcoat layer often contains polymers, nanoparticles, and various other chemistries to achieve desired properties.

Our hardcoats can deliver a variety of finishes to meet customer specifications. We devise the coating’s precise chemistry to meet specific application needs, depending upon the characteristics required for use. Critical factors include:

Hardness

Applications call for varying degrees of hardness. Hardness testing is complex and subjective even given ASTM methods. For example, 3H hardness levels are commonly used for flexible and small feature devices such as roll-up screens and film processing applications. These projects demand special properties and characteristics that are ordinarily considered diametrically opposed. They require a delicate combination of thin, flexible attributes, combined with the hardness qualities specified for the product’s end use. In contrast, 6-9H hardness levels are used for top touch surface/cover glass replacement applications, which require a more durable surface.

Carestream works with customers to achieve the preferred hardness level for each application. Our hardcoat projects undergo rigorous hardness testing as well as evaluations of coating thickness and flexibility properties. Test methods are described in our Hardness Testing for Hardcoat Film Applications blog.

Optical Clarity

Hardcoats must not be hazy or cloudy. Highly transparent films are required to eliminate image distortion and allow the viewer to see all the fine product features underneath. Chemistries used to produce optically clear hardcoats can cause Newton’s rings, a visual distraction for the viewer. Newton’s rings create a visual “rainbow” pattern on touch screen displays. Carestream has developed a hardcoat that eliminates these patterns.

We also use our expertise and coating assets to eliminate light reflection that could otherwise degrade the touch screen’s usefulness – resulting in the delivery of high transparency, low haze and anti-reflection/anti-glare properties.

Environmental Challenges

UV lighting, chemicals, humidity and fingerprinting (handling, marring, and rubbing) can all have a major impact on the performance and function of a touch screen product. Depending on the customer’s needs and applications, we work with them to design and produce innovative multi-layered or single-layer solutions in order to meet multiple product requirements with a single component structure.

Carestream’s innovative hardcoated film features formulations usable on a variety of substrates to deliver a variety of finishes meeting various specifications. Our hardcoat projects undergo rigorous hardness testing as well as evaluations of coating thickness, chemical resistance, flexibility, cleanliness and optical properties. These exacting guidelines apply to every roll in the production environment – ensuring that the process and product quality meet customer expectations.

For more information about Carestream’s Hardcoat Films for Electronics, visit: http://www.tollcoating.com/how-hardcoat-films-protect-electronics-and-other-advanced-materials-products/.

For additional information on our hardcoat services, visit: http://www.tollcoating.com/services/hardcoat/ or download our Carestream Hardcoat Film Datasheet.