LED maker Osram Opto has joined a German project to explore the principles of high-resolution displays using arrays of micro LEDs (?LEDs).
Osram will work alongside ASM Amicra and Fraunhofer IISB in the SmartVIZ project, which has funding from the Bavarian state ministry for regional development.
Their potentially high luminance (light output per unit area) could put ?LEDs ahead of other emissive technologies such as OLEDs in space-constrained applications such as augmented reality glasses. UK-based Plessey recently switched its development focus entirely onto monolithic ?LED arrays.
The focus of SmaryVIZ appears to be sparse arrays of ?LEDs for automotive interior applications. Over the next two and a half years, according to Osram, it aims to build the foundations of transparent high-resolution direct-viewing displays – intending to produce a demonstrator at its conclusion in October 2021.
The three parts will be:
- Design of efficient red, green and blue ?LED structures
- Handling sub-components
- Display assembly
“Implementation of such concepts and applications requires in-depth studies of the underlying physical principles that are in-part entirely different than today’s macro LED chips,” said Osram.
Transparent and flexible image encoders will feature, as will transparent substrates based on indium gallium zinc oxide thin-film transistors (IGZO TFTs) for controlling individual pixels.
“This approach allows for quasi-transparent surfaces, which can be filled with content only if the ?LEDs are switched to active,” said Osram. “Employing such an active matrix backplane for the driver electronics allows image rendering with ?LEDs to produce visualization scenarios with ultra-high resolution.”
Unlike the monolithic Plessey approach, which produces micro-displays, SmaryVIZ will be developing automated ways to transfer high numbers of ?LED die from source wafers to the backplane electronics.
Requirements include ~1.5?m positioning accuracy of chips <40?m across. This “will require entirely new technological approaches, which will be addressed within the project” said Osram. “The consortium partners have the necessary expertise to realise the envisioned technological breakthrough.”
ASM Amicra is a production automation specialist with knowledge of photonic component micro assembly.
Fraunhofer IISB (Institute for integrated systems and device technology) specialises in power electronics and technologies for producing semiconductor devices. It will design and manufacture transparent electronic circuits.
Osram SmartVIZ project leader Hubert Halbritter 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”.