A printed flexible hybrid electronics (FHE) technology platform is described, which combines a thin-film audio speaker, printed interconnects, and printed passive components in a highly flexible system. Bimorph piezoelectric polymer speaker structures were developed and shown to give increased loudness compared with a single layer speaker, with good fidelity and easily recognizable sound. Speakers were fabricated on flexible thin polyimide substrates, which enables integration with printed electronics and other thin-film devices. Two demonstrator circuits were designed to operate the speakers and were fabricated using printed FHE techniques. One circuit was an amplifier for a portable music player, and the second provides a record and playback function using an audio integrated circuit. The fabrication of these devices included ink-jet printed interconnects and ink-jet printed resistors, which showed a good long-term stability and flexibility.

Printed and flexible hybrid electronics is an emerging technology with potential applications in smart labels, wearable electronics, soft robotics, and prosthetics. Printed solution-based materials are compatible with plastic film substrates that are flexible, soft, and stretchable, thus enabling conformal integration with non-planar objects. In addition, manufacturing by printing is scalable to large areas and is amenable to low-cost sheet-fed and roll-to-roll processes. FHE includes display and sensory components to interface with users and environments. On the system level, devices also require electronic circuits for power, memory, signal conditioning, and communications. Those electronic components can be integrated onto a flexible substrate by either assembly or printing. PARC has developed systems and processes for realizing both approaches. This talk presents fabrication methods with an emphasis on techniques recently developed for the assembly of off-the-shelf chips. A few examples of systems fabricated with this approach are also described.

Wireless sensing has broad applications in a wide variety of fields such as infrastructure monitoring, chemistry, environmental engineering and cold supply chain management. Further development of sensing systems will focus on achieving light weight, flexibility, low power consumption and low cost. Fully printed electronics provide excellent flexibility and customizability, as well as the potential for low cost and large area applications, but lack solutions for high-density, high-performance circuitry. Conventional electronics mounted on flexible printed circuit boards provide high performance but are not digitally fabricated or readily customizable. Incorporation of small silicon dies or packaged chips into a printed platform enables high performance without compromising flexibility or cost. At PARC, we combine high functionality c-Si CMOS and digitally printed components and interconnects to create an integrated platform that can read and process multiple discrete sensors. Our approach facilitates customization to a wide variety of sensors and user interfaces suitable for a broad range of applications including remote monitoring of health, structures and environment. This talk will describe several examples of printed wireless sensing systems. The technologies required for these sensor systems are a mix of novel sensors, printing processes, conventional microchips, flexible substrates and energy harvesting power solutions.