Samsung Display expects that XR devices will eventually use a single panel display

Forming LEDs on a CMOS substrate poses a cost hurdle

Samsung Display expects LED-on-silicon (LEDoS) displays used in augmented reality devices to be a monolithic single panel, a senior executive said.

Samsung Display vice president Huh Jong-moo said Thursday at TheElec’s Microdisplay conference that LEDoS technology is expected to evolve from blue and quantum dots (QD) to three RGB panels, to ultimately a monolithic single panel.

LEDoS is a technology that creates countless micrometer-sized LEDs on a silicon substrate.

The technology is being touted as the future of microdisplays in augmented reality devices due to its brightness advantage.

Blue and QD LEDoS are created by forming blue LEDs on a CMOS panel or backplane. A QD layer with a microlens array on top is used to realize other red and green colors and increase brightness.

Three RGB panels use three CMOS panels, each with red, green and blue LEDs. This method requires waveguide technology to control light waves.

Monolithic single panel uses only one CMOS panel with the R, G and B LEDs placed on it either arranged vertically or arranged together horizontally.

Huh said R, G and B OLEDs can be coated together on glass or CMOS panels, but the LEDs require a high-temperature epi process.

However, he added that RGB LEDs must be individually made before being mounted on a CMOS panel, hence the difficulties and cost concerns.

This means that LEDoS on microdisplays was not just an evolution of OLED, but required new technologies in optics, panels, processes and materials that could create new value for the display industry, the vice president said.

Reality devices have not yet launched due to lack of content, device inconvenience and high cost, Huh said, emphasizing that the micro display market is still in its early stages.

In 2022, Samsung Display launched Project M to develop LEDoS and OLEDs on silicon microdisplays for reality devices.