Economically Integrating Antennas in Mobile Phone Shells

Bayer MaterialScience has developed and applied for a patent on a technology that enables the efficient production of highly integrated electronic components with complex geometries. It is based on polycarbonate films and the use of printed polymer electronics, and it is suited for the direct integration of antennas in mobile phone shells.

Mobile phones are becoming increasingly high-powered, offering users today a wide variety of functions that require the integration of additional antennas, for example. In future devices, the number could grow to 16 to cover bandwidths such as GSM, UMTS, Bluetooth, and Wifi, as well as RFID for near-field communication applications. But neither the exterior dimensions of the devices themselves nor the already low film thicknesses of the mobile phone shells should increase as a result.

“Besides the formability advantage, the process offers cost advantages over the common electrolytic deposition method,” says Elisa Picasso, business development manager for functional films at Bayer MaterialScience. “The printed antennas are extremely thin and easily accommodated even in small mobile telephone shells.”

Three-dimensional electronic components are then made from the printed films using the film insert molding (FIM) process. The company is collaborating on the project with, among others, the Molex company, a world-leading direct supplier to the mobile communications industry, and Niebling-Junior Kunststoffverarbeitung – Werkzeugbau e.K.

Polycarbonate films in the Makrofol HF range, which Bayer MaterialScience currently is expanding, offer additional possibilities for the production of electronic components. The films have a scratchproof surface with a deep-gloss finish (piano effect), and are gently and precisely formed in the high pressure forming (HPF) process. Even small radii and high depths of draw can be achieved. The precured coating is subsequently given a final cure with UV light, before the film is back-injected with plastic using the film insert molding process. Components with a rating of “1H” or better in the pencil hardness test can be manufactured using this technology.

One of the first representatives of this product family, Makrofol TP 278, is used by Albrecht Jung GmbH & Co. KG for the display of its new KNX compact room controller. FIM technology further makes it possible to apply a variety of attractive decorations via a screen printing process, where the printed image is protected by the film. This is what makes the films so highly advantageous for use in housings and displays in the entertainment electronics sector, in mobile phones and in decorative 3D panels in automotive interiors.

“Our development partners benefit from the fact that our Technical Service Center for Films is equipped with state-of-the-art machinery and equipment covering every stage of the FIM process chain for producing printed polymer electronics,” said Picasso. For example, the Functional Films unit employs screen printing systems, rapid prototyping and HPF units that allow printed films to be thermoformed with minimal distortion. Rounding out the FIM process chain are injection and injection-compression molding machines of various sizes that are equipped with the relevant facilities for film processing.