Quantum Dots Shrink Pixels from 30 Microns to 4 Microns

Nanoco Technologies and Plessey Semiconductors have partnered to shrink the pixel size of monolithic microLED displays using Nanoco’s cadmium-free quantum-dot (CFQD quantum dots) semiconductor nanoparticle technology.

Using its existing gallium nitride (GaN)-on-silicon monolithic process, Plessey will integrate the CFQD quantum dots into selected regions of blue LED wafers to add red and green light, shrinking the smallest practical pixel size from today’s 30 µm to 4 µm, a reduction of 87%.

the quantum dots are applied onto microLED arrays using an inkjet process, for which the two companies will file a joint patent. “Quantum dots offer the best solution for today’s emerging display requirements,” Lee said. “The nano-sized emitters with narrow band emission make them a suitable solution for Plessey’s microLED display roadmap, which will see pixels being driven down to 4 µm in size in 2019.”

Lee added that because the company has its own GaN-on-silicon fab, Plessey has been able to optimize the process to achieve very good wavelength uniformity across the 8-inch wafer as well as the ability to add red and green to the native blue GaN silicon.

Compared with other display technologies, microLEDs are brighter, smaller, lighter, and more energy-efficient and have a longer operating life. Where they replace OLEDs — for example, in AR/VR goggles or head-up displays — Plessey claims that its microLEDs offer 10 times the resolution, 100 times the contrast ratio, and up to 1,000 times the luminance. They do so at half the power consumption, doubling battery life in portable devices. They also feature perfect blacks, realistic color, and immunity to burn-in or decay over time.