SmartVIZ project exploring high-resolution visualization technologies using micro-LEDs

Osram Opto Semiconductors GmbH of Regensburg, Germany says that, together with Regensburg-based ASM AMICRA Microtechnologies GmbH and the Fraunhofer Institute for Integrated Systems and Device Technology (IISB) of Erlangen, Germany, it is part of the project SmartVIZ – which began in November 2018, funded by the Bavarian State Ministry for Economic Affairs, Regional Development and Energy – that is exploring the principles of high-resolution visualization solutions using micro-LEDs (µLEDs).

There is still no standard definition for the term µLED, only a loose guideline for the opto chip’s dimension to include edge lengths smaller than 100µm. Since µLED technology can produce extremely high luminance over a wide dynamic range, it can play a key role for future megatrends such as augmented reality (AR) applications, says the firm. The project’s focus is on automotive interior applications. It is expected to complete in October 2021, when an initial demonstrator will be presented.

Imaging devices based on direct-emitting µLED pixels are considered to be a disruptive development in the visualization market and have the potential to sideline technologies such as liquid-crystal displays (LCD) or organic light-emitting diodes (OLEDs). These rather conventional technologies are constrained by their fundamental limits in energy efficiency, contrast, luminance, functionality and other associated restrictions, says Osram Opto. Over the next two and a half years, SmartVIZ aims to provide the basis for future transparent, high-resolution, direct-emitting visualization solutions using µLED technologies.

The work packages will focus on three key technologies: (1) the design of efficient µLED light sources; (2) their handling on the sub-component level; and (3) final assembly. Red, green and blue µLED structures will perform as efficient high-luminance image pixels. Implementation of such concepts and applications requires in-depth study of the underlying physical principles that are, in part, entirely different from existing macro-LED chips.

The project will also conduct research addressing the component integration of µLEDs using a novel approach for transparent and flexible image encoders. Transparent substrates based on indium gallium zinc oxide thin-film transistors (IGZO TFTs) will be the focus for controlling the individual pixels. This approach allows for quasi-transparent surfaces, which can be filled with content only if the µLEDs are switched to active. Employing such an active-matrix backplane for the driver electronics allows image rendering with µLEDs to produce visualization scenarios with ultra-high resolution.

Another work package will target processing concepts to enable rapid transfer of large quantities of µLED chips from a source wafer to the backplane driver electronics via automated parallel assembly. The key requirement is a positioning accuracy of about 1.5µm. Researching accurate transfer methods for such small chips (with an edge length smaller than 40µm) will require entirely new technological approaches, which will be addressed in the project.

The project consortium reckons that partners have the necessary expertise to realize the envisioned technical breakthrough. For example, ASM AMICRA has expertise in production automation, especially in photonic applications. The firm has in-depth knowledge of the micro-assembly of photonic components. The Fraunhofer Institute for Integrated Systems and Device Technology (IISB), which specializes in power electronics and technologies for producing semiconductor devices, will design and manufacture transparent electronic circuits for their final installation in micro-pixel visualization components.

Hubert Halbritter, SmartVIZ project leader at Osram Opto Semiconductors, described his company’s role “as a project partner with in-depth experience in micro-pixel imaging components that will research efficient, high-luminance pixels. Along with our partners, we aim to gain technology leadership in one of the key future technology markets.”

Tags: microLED

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