MicroLED tech development a much watch: Korea University professor

Research into MicroLED technology was active in the US, Taiwan and Europe while there was none done by South Korean companies or institutes, a South Korean professor noted during a display industry conference in Seoul.

Speaking at the 2022 SID Review Workshop, Korea University professor Hong Moon-pyo said the local industry must keep watching the technology development in MicroLED to gauge how to react.

MicroLED uses LED chips that are under 100 micrometers in size as pixels on the display panel.

South Korean firms Samsung and LG Electronics are launching signage and TVs that use the technology.

However, core technologies to realize these products were led by Taiwanese companies such as PlayNitride, Hong noted.

MicroLED could have an advantage in terms of competing technologies such as liquid crystal display and OLED in making the panel larger, transparent or ultra-small, the professor claimed.

LCD and OLED will require glass substrates to become around 100-inch size but MicroLED doesn’t require this and can use smaller-sized tiles to be assembled to that size, Hong said.

MicroLED is also of high interest for ultra-small displays that could be used in augmented and virtual reality devices, he said.

Companies such as PlayNitride were continuing to develop technologies for the transfer process in MicroLED production as well, the professor said.

During production, micrometer-sized LEDs are transferred onto the substrate, a difficult process that determines the yield and cost of the panels.

Hong noted that the Taiwanese company had the most complete technology when it comes to MicroLED production processes. PlayNitride currently transfers the LED chips onto a carrier before it transfers them onto the substrate, a technology the company calls chip on carrier, or CoC.

The pixel combination and inspection are done on the carrier before they are transferred to the backplane substrate, Hong said, which allows the company to easily swap out defective chips on the carrier beforehand.

At the same time, when MicroLED was first commercialized, the transfer process was a big issue but it only accounts for 10% of the cost, the professor said.

Interest in the fundamental technology around the micrometer-sized LED chips is getting higher, he added.

Still, South Korean companies are ahead of their Chinese and Taiwanese rivals when it companies to OLED technologies.