Wet-chemical printing procedures offer a cost-effective alternative to conventional sputter techniques and cut down the number of required process steps.
To enable mass production in advanced display technology, manufacturing must be cost-effective and simple. This can best be achieved through more adaptable and cheaper materials but solutions for some important key details had been lacking and conventional materials tend to be expensive or not versatile enough.
The new Fraunhofer ISC sol-gel materials and inorganic-organic hybrid polymers now allow just such a simple and cost-effective processing with wet-chemical printing or roll-to-roll processes. They also advance optical, mechanical and electrical properties to open up a whole new range of applications and design options for flexible, transparent or 3D displays.
Up to now, there was no technology to realize flexible and transparent touchscreens with corresponding electronics. Fraunhofer ISC now presents the material, already put to use within the EU-funded “Flashed!” project: printed quasi-transparent polymer piezo-sensors. These sensors register deformation, e.g. when bending a display; pressure, e.g. applied by a fingertip; and, if demanded, changes in temperature.
This is why they work equally well for large curved surfaces, for turn-over displays or the on-screen operation of a flexible tablet – none of which is possible with an indium-tin-oxide-based touchscreen display. A simple screen printing process is all it takes to apply the sensor pastes onto PET films.
Fraunhofer ISC materials are equally beneficical as intermediate layers, e.g. in OLED lighting panels. While OLEDs can be produced at low cost and are economical in use, they nevertheless suffer from scatter loss of light owing to rough interfaces between conductive and protective layers. The scattering action could be much better controlled with a smooth, high refractive index, sol-gel based layer incorporating scatter centers.