Microdisplays on CMOS backplanes have also been demonstrated by companies including Plessey, glō, Lumens, JB Display, Sharp and Ostendo. Finally, discrete microdriver ICs have been developed by X-Display. The multiple prototypes based on TFT backplanes give credit to the idea that microLED displays could leverage existing panel maker capacity, thereby simplifying and streamlining the supply chain.
“Equipment makers have taken notice and are starting to develop microLED-specific tools for assembly, bonding, inspection, testing and repair”, notes Virey.
LED makers can’t afford to ignore the technology pressure and are showing interest, with San’an planning to invest US$1.8 billion to set up a mini and microLED manufacturing base. Osram, Seoul Semiconductor, Nichia or Lumileds are also increasing their activity and Playnitride is completing its first microLED pilot line.
However significant roadblocks are still in place for key applications… For many of them, economics are pushing die size requirements below 10μm. This compounds efficiency, transfer and manufacturability challenges and despite significant improvements, small die efficiency remains low. In most cases, display efficiency based on this technology still can’t match that of OLED . Significant effort is therefore needed to further improve the internal quantum efficiency, light extraction and beam shaping of green and red microLED chips.