Fraunhofer IPMS Develops Semi-Transparent Microdisplays for Augmented Reality Systems

Fraunhofer Institute for Photonic Microsystems (IPMS) has introduced an innovation in augmented reality (AR) display technology with the development of a semi-transparent microdisplay, as part of the HOT project (High-performance transparent and flexible microelectronics for photonic and optical applications). It will be showcased at the upcoming SID Display Week 2024 in San Jose, USA.

Source: Fraunhofer IPMS

OLED microdisplays have long been recognized for their suitability as image generators in VR, AR, and MR applications due to their high resolution and technological maturity. However, their inherent lack of transparency, stemming from their silicon-based technology, has presented challenges in the development of see-through AR devices. The conventional solution involving complex optical systems adds weight, size, and compromises optical efficiency.

Drawing on years of expertise in microdisplay design, Fraunhofer IPMS researchers have devised a novel approach using semi-transparent OLED-on-silicon microdisplay technology. By integrating thinner circuitry layers and micro-optics directly onto the chip, the transparent microdisplay doubles as an optical combiner element. This integration optimizes the optical system, significantly reducing size and improving efficiency.

Philipp Wartenberg, Group Manager of IC and System Design at Fraunhofer IPMS, elaborated on the technological breakthrough: “Our innovative method, leveraging modern silicon CMOS processes on silicon-on-insulator wafers, allows for the implementation of exceptionally thin circuitry layers. This, combined with specific IC design and process flow, facilitates the transfer onto a glass wafer, enabling the realization of semi-transparent microdisplays.”

The HOT project, supported by Fraunhofer IOF, represents a collaborative effort aimed at advancing transparent and flexible microelectronics for photonic and optical applications. Through this initiative, Fraunhofer IPMS continues to solidify its position as a leader in applied research and development in photonics and microsystems.