Porotech creates native red InGaN microdisplay

Porotech, a specialist developer of micro-LEDs, has built what it says is the world’s first microdisplay based on native red indium gallium nitride (InGaN) – with an active area of 0.55 inches diagonally and a resolution of 960×540.

According to the Cambridge University spin-out, until now, it has only been possible to produce blue and green microdisplays using GaN-based light-emitting devices – with red emission relying on devices based on aluminium indium gallium phosphide (AlInGaP). AllnGaP, however, has tended to struggle at small pixel sizes, so there is a drastic efficiency drop as the device size decreases. And, to produce a full-colour display, the light from different panels has had to be combined.

Porotech said that this breakthrough means that, for the first time, all three light-emitting elements can be produced using a single toolchain – and it removes the complexities of mixing devices based on different material structures.

Micro-LED displays are one of the technologies that are being considered for the growing augmented-reality market.

“AR technology is set to be a game changer and micro-LEDs are particularly vital for the advancement of AR interfaces,” said Porotech CEO and co-founder Dr Tongtong Zhu. “In traditional liquid crystal displays (LCDs) the image is a result of both modulating and filtering the light from a white back-lighting module. This inefficient and the various filtering, diffusion and modulation stages of the LCD display impose limits on how lightweight the final display can be.

“Emissive display technologies, on the other hand, only produce the light that is required of them – allowing for the final devices to potentially achieve much higher efficiencies. Self-emitting displays based on inorganic semiconductors can also be produced in monolithic fashion, allowing them to more easily scaled down than traditional LCD or organic Semiconductor displays – allowing for smaller, lighter, brighter and reliable high-resolution displays to be made.”

“Porotech‘s new class of porous GaN Semiconductor material enables the creation of efficient and bright native red InGaN micro-LEDs and microdisplays,” said Dr Zhu. “This has been the missing piece of the puzzle until now. As well as reducing costs, the bright native red can push the maximum achievable wavelength to 640nm and beyond – a first for microdisplay visualisation. Our breakthrough is now set to accelerate the commercialisation of AR glasses as well as heralding a new era of brighter, sharper, more vivid microdisplays for products such as smartphones and smartwatches.”