The activity badge is a small clip on badge that displays the wearer’s activity level using dynamic printed graphical elements. The heart-shaped graphical elements are created using co-planar electrochromic technology, which is non-light-emitting. Even though the badges are still at the prototype phase, the low power consumption of the electrochromic display enables operation for more than a year on a single coin cell battery.
The activity badge is a prototype that demonstrates the potential of hybrid integration of printed, flexible electronics in combination with conventional electronic components. With this approach, end-user products can be created using production scale manufacturing technologies. In addition, the badge demonstrates the integration of electrochromic display elements through injection molding.
A prototype production run of activity badges was built at VTT,Finland, Printocent pilot factory manufacturing line using the following processes:
- Electrical wiring and electrochromic PEDOT:PSS ink were applied to a flexible PET substrate using rotary screen roll-to-roll printing
- The electrochromic display was finalized by mounting spacer and lid as well as dispensing the electrolyte
- Conventional electronics components, including a CPU and accelerometer, were assembled by VTT’s roll-to-roll capable pick and place facility
- The CPU was programmed
- The individual badges were laser cut from the sheets
- A thermoplastic polyurethane frame, creating a cover and battery holder, was applied by injection molding
To validate the feasibility and scalability of the processes used, a total of 100 pieces were fabricated. These giveaway demonstrators were launched at Prinse’18 conference, held in February 2018 at VTT in Oulu.