July 9, 2016

The novel “LTM materials” are thin, flexible, luminous and touch-sensitive, thanks to flexible and transparent OLEDs combined with an advanced polymeric piezo material. Manufactured on plastic substrates, they expand design freedom and unlock totally new ways of product-user interaction through affordable and intuitive user interfaces. Together, these unique features allow seamless integration of the LTM materials into parts and products up to the point where the product becomes the interface.

The materials stream in Project LTM developed these novel smart materials consisting of four distinct technological components: a back layer with control electronics [i.e. flexible wiring, power supply, input-output switching IC], a piezo plastic sensor for touch sensitivity, OLEDs for luminescent response and a conversion layer for modifying colour.

Integration of the LTM smart materials in the design concepts has proven to be considerably more challenging than anticipated, and largely remains as future work – although promising solution directions have been identified (e.g. stitching as a viable joining/integration method).

A specific challenge is formed by the fact that the OLEDs cannot survive long-term temperatures over 60-70°C, which either rules out certain common processes or necessitates the application of suitable barrier layers between e.g. OLED and a relatively hot molten plastic; chemical compatibility may also make specific demands.

Other integration issues were identified such as: defining the minimum size of the OLED that can guarantee precise interactions, striving for maximum reduction of the control box in order to integrate it nicely into the product, enabling neat integration and high flexibility of all the components, including control box and battery, in order to provide high wearability and comfort, exploring OLEDs’ output in terms of colour and coherence [programmability] and PIEZO sensitivity in order to offer correct feedback and guarantee good user interaction.

Solving these issues means overcome the integrations obstacles and be able to produce a sizable number of successful demonstrators which have been shown to a large audience on June 17th 2016 at the project’s closing symposium in Delft.