Nanoco and Plessey partner to shrink full-colour micro-LED pixels by 87%

Plessey Semiconductors Ltd of Plymouth, UK and Nanoco Technologies Ltd of Manchester, UK have partnered to shrink the pixel size of monolithic micro-LED displays using Nanoco’s cadmium-free quantum dot (CFQD) nanoparticle technology.

Using its existing proprietary monolithic gallium nitride on silicon (GaN-on-Si) process, Plessey will integrate the CFQD quantum dots into selected regions of blue LED wafers to add red and green light. This shrinks the smallest practical pixel size by 87% from 30µm currently to just 4µm, a reduction. The process should enable the production of smaller, higher-resolution micro-LED displays in applications such as AR/VR devices, watches and mobile devices, while enhancing both colour rendition and energy efficiency.

For pixels of 30µm or greater, colour conversion is currently performed by adding phosphors to the blue die. However, since the smallest phosphor particle is around 30µm, the efficiency of colour conversion deteriorates as the pixel size shrinks. Nanoco’s CFQD technology overcomes this limitation while facilitating efficient, compact device packaging.

“Quantum dots offer the best solution for today’s emerging display requirements,” says Mike Lee, president of corporate & business development at Plessey. “The nano-sized emitters with narrow-band emission make them a suitable solution for Plessey’s micro-LED display roadmap, which will see pixels being driven down to 4µm in size by 2019,” he adds.

“The combination of Plessey’s blue micro-LEDs with Nanoco’s red and green cadmium-free quantum dots gives display customers the performance they require to rapidly commercialize products,” says Dr Brian Gally, Nanoco’s head of product.

Compared with other display technologies, micro-LEDs are brighter, smaller, lighter, more energy-efficient and have a longer operating life, it is claimed. Where they replace organic light-emitting diodes (OLEDs) - for example in augmented reality/virtual reality (AR/VR) goggles or head-up displays - Plessey says that its micro-LEDs offer ten times the resolution, 100 times the contrast ratio and up to 1000 times the luminance while consuming half the power, doubling battery life in portable devices. The firm also claims that they feature perfect blacks, realistic color and immunity to burn-in or decay over time.

Plessey is showcasing its micro-LED technology at the Consumer Electronics Show at stand 22048 (South Hall 1) in the Las Vegas Convention Center (8-11 January). The firm was recently named as a ‘CES 2019 Innovation Awards Honoree’.

Tags: Plessey GaN-on-Si microLED

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