MicroLED LTPS - Page 2

Taiwan-based display maker Innolux demonstrated a 12.3" microLED tiled seamless display module prototype, based on an LTPS backplane. The display achieves a brightness of 700 nits and a resolution of 480x180 (40 PPI)

The display is driven by an active matrix backplane, and uses inkjet-printed quantum dots based color conversion system (which we do not have any more info for, as of now). The LEDs themselves are 20x40 um in size.

AU Optronics have been showing new microLED display prototypes, and the following video from Insight Media shows the company's booth and new displays at SID Displayweek 2022.

You can see AUO's stretchable 141 PPI display (a very interesting demo, developed together with PlayNitride), the rollable 14.6" 2K (202 PPI) LTPS microLED display, AUO's 1.4" circular 454x454 (326 PPI) microLED another stretchable microLED, this one 6.45" in size with a 900x450 resolution (163 PPI), and finally AUO's 17.3" 2000-nits 1280x720 transparent (60% transparency) microLED prototype.

Tianma Microelectronics held its first "2021 Micro-LED Ecosystem Alliance Conference" in Xiamen, China, during which several producers and researchers gathered to discuss microLED technologies and challenges.

During the conferences, Tianma showed several new microLED prototype display, including some new ones. The first display is a 9.38" 960x480 (222 um pixel pitch) transparent LTPS panel. Tianma's second-gen transparent panel features higher transparency (>70%), larger size and a refined TFT process compared to the company's first-gen transparent microLEDs shown in 2019.

According to reports from Korea, Samsung Display recently approached AU Optronics with a request to develop a 12.7" microLED LTPS TFT backplane to be used in Samsung's MicroLED TVs.

These new backplanes will be used in Samsung's 2022 microLED TVs. This will be a change from Samsung's current microLED TVs that use printed circuit boards (PCBs), and will allow Samsung to release TVs with higher pixel densities, and thus enable smaller 4K TVs. According to the report, Samsung's plan is to launch 89-inch, 101-inch and 114-inch LTPS-based microLED TVs in 2022.

Towards the end of 2020, Samsung announced it's first "consumer" 110-inch 4K MicroLED TV, and then in early 2021 it said it will release smaller microLED TVs, including 77" and 88" models.

According to a new report from Korea, Samsung Electronics canceled its plans to release these smaller microLED TVs, as the company could not reduce prices enough and the asking price for a 77" microLED would not be attractive to customers.

Quantum Dots developer Nanosys announced that it acquired 3D Nanowire microLED display developer Glo. The financial details were not disclosed.

Glo has been developing GaN microLED displays on both LTPS and CMOS (microdisplay) backplane. The company, founded in 2003, has invested (according to Nanosys) over $200 million in its technology - which includes epitaxial LED growth, transfer technology and chip processing.

Tianma demonstrated several new microLED display prototypes at SID Displayweek 2021. First up is a 7.56" 720x480 (114 PPI) flexible MicroLED display, developed in collaboration with PlayNitride. The display is driven by an LTPS backplane and achieves a brightness of over 600 nits. The bending radius is 50 mm.

The second display is a tiled display that combines two 5.04" 480x320 (114 PPI) LTPS microLED displays. This one was develop again in collaboration with PlayNitride. The border (bezel) of the panel is less than 0.03 mm - although looking carefully at the display you can see a black line separating the two panels.

AUO Optronics will demonstrate several new MicroLED display prototypes at Touch Taiwan 2021. AUO now brands its microLED displays as ALED displays.

The first display, which you see above, is a 1.39-inch 472x472 (338 PPI) full-circle microLED display. AUO says that this is the highest-density MicroLED display ever developed. AUO did not disclose more about this display (which was developed together with PlayNitride) but the company says that it offers ultra-wide viewing angles and high brightness.

Laser equipment maker Coherent says that it saw a "significant increase" in the level of investment and bookings related to MicroLED displays. These tools are going to be used for process development, as a precursor to mass production.

Coherent reveals that its MicroLED customer base includes almost all current OLED and LCD manufacturers and many well-known MicroLED specific startups and display industry integrators. Coherent is offering multiple UV solutions for four separate MicroLED processes - CLA for high performance low power consumption back planes, laser lift-off for customers using sapphire carrier, laser transfer and laser repair.

This article is the second article in a short series of articles that discuss the efficiency of microLED displays. Our previous article discussed the quantum efficiency of microLED chips - with a conclusion that these can be quite efficient.

This article will look at the entire microLED display, and also compare it to current LCD and OLED displays. After all one of the main advantages of microLED displays is the increased efficiency (and brightness) compared to current displays. Most people assume that indeed microLEDs are much more efficient than OLEDs and LCDs.