In this case study, the possibilities of hybrid integration of printed and flexible electronics in combination with conventional electronic components to create new types of product concepts is demonstrated. The final result is a personal activity meter demonstrator, which is realized by utilizing various flexible electronics manufacturing and integration techniques. Roll-to-roll printing was used to print the electronic backplane as well as co-planar electrochromic (EC) display. A pick-and-place assembled microcontroller unit and accelerometer, together with passive components, provided the brains for the system. Injection molding was then utilized to create a structural electronics system including an EC display. To validate the feasibility and scalability of the processes used, 100 pieces of the personal activity meter were fabricated. Modeling with continuum computational fluid dynamics and numerical heat transfer, using the high-performance finite volume method, showed that high filling pressure and shear-stress are the key factors causing broken devices. The stability of the devices in harsh environmental conditions as well as in bending seem to be slightly improved in the over molded samples.
Kololuoma, T., Keränen, M., Kurkela, T., Happonen, T., Korkalainen, M., Kehusmaa, M., Gomes, L., Branco, A., Ihme, S., Pinhero, C., Kaisto, I., Colley, A., & Rönkä, K. (2019). Adopting Hybrid Integrated Flexible Electronics in Products: Case—Personal Activity Meter. IEEE Journal of the Electron Devices Society, 7, 761-768. https://doi.org/10.1109/JEDS.2019.2903868