High definition overlays from polyester film

Autotex polyester films from Autotype International are being used by Danielson to enable the company to produce high definition, photographic quality keyboard overlays from screen printing systems.

Autotex polyester films from Autotype International are being used by Danielson, one of the leading European manufacturer of membrane keyboards and touch screens, to enable the company for the first time to produce high definition, photographic quality keyboard overlays from the latest generation of screen printing systems.

Danielson has traditionally used conventional screen printing techniques to produce a range of custom developed and manufactured membrane keyboards and panels.

The company has built a reputation for product innovation and design quality but until recently had been limited in the variety of printed graphics overlays it could offer by the nature of the screen process, which placed a physical limit on mesh size and thus image definition.

In addition, complex multi-colour graphics required several print passes to build up colours one by one; this was a time consuming and costly exercise that placed a restriction on productivity.

Recent developments in screen print technology have, however, enabled Danielson to offer its customers a far wider choice of high definition finishes at up to 60 lpi, and which incorporate photographic images, rasters, fine colour gradients and specific design elements to enhance the functionality of keyboards.

A crucial part of this new process is the use of UV inks, which offer a number of benefits over traditional solvent and water based inks.

In particular, they enable extremely fine screen meshes to be used, for high definition photographic quality images; are free from volatile organic compounds (VOCs), thereby improving process conditions and operator safety; and dry extremely rapidly, within seconds, so productivity can be significantly improved.

Conventional polyester and polycarbonate overlays cannot, however, easily be printed using UV inks, so Danielson turned to Autotype as its preferred supplier of substrate materials for a solution.

Autotype were able to offer a special primer layer, applied to the reverse, or print side, of Autotype's standard Autotex and Autoflex range of textured and hardcoated overlay films.

As Ben Phelan, Business Development Manager for Danielson, explains, "We have previously used Autotex and Autoflex and have found that these materials are easy to handle and process, especially with tactile or domed switch constructions, where they consistently give a switch life in excess of 5 million actuation.

Perhaps as importantly, they provide exceptionally high levels of chemical and mechanical resistance, making them ideal for use in keyboards that have to withstand continuous use in harsh operating environments." A further benefit of Autotex and Autoflex is the optical clarity of each film, with almost no light loss or diffusion, so that ink colours and printed images on the underside remain correctly saturated, vibrant and sharp.

Ben Phelan adds, "With the special film versions with the UV primer, we have retained all of the traditional benefits of the Autotype products but have the ability to offer our customers new standards in print quality and definition and at higher production speeds.

In particular, our keyboard development team is now able to create a far wider range of designs, that enhance both the aesthetics and functionality of membrane systems, while giving our customers the opportunity to repackage and differentiate their products clearly from their competitors.".

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