Canada-based microLED technology developer VueReal demonstrated a new transparent microLED display. The display is between 3 and 4 inches in size, with high brightness (over 3,000 nits) and very high transparency (85%).

The display in the video is produced on glass, but VueReal can also produce displays on flexible substrates. The company did not disclose the display's resolution (or whether this is a segmented display).

The founder and General Manager of Bolite Optoelectronics, Dr. Bowen Cheng, was invited to present at the recent Touch Taiwan 2021 Conference in April. The title of his talk was “Laser Processing Applications for the Manufacturing of Mini and MicroLED Displays.” Since it was presented in Mandarin only, microled-info.com caught up with Dr. Cheng to learn more about this trending subject and the company he started.

Q: Dr. Cheng, can you please tell us a little about your background, prior to starting Bolite?

I was a research engineer at Xerox PARC and helped develop surface micromachined microspring interconnects in a project funded by the U.S. Army Research in collaboration with Oracle. I was also a vital member of the team that successfully demonstrated the world's shortest wavelength diode laser at the time, a 250 nm UV laser for military applications. With these experiences in both semiconductor laser processing and MEMS processing, I decided to start Bolite and build a team to develop state-of-the-art laser solutions for microprocessing applications.

Q: I must admit I’ve not heard of Bolite before. What differentiates you from other laser microprocessing companies?

This is a guest article by IdeaFarm LLC

A potentially key advantage for microLED displays is the ability to effectively integrate far-field image sensing within the display because of the large “open” pixel area compared to other display technologies. The basic feasibility and advantages of integrating far-field image capture within a microLED display was reported on by IdeaFarm LLC at the recent Displayweek 2021 conference (the major worldwide display technology conference). IdeaFarm proposes to integrate an array of miniature wafer-based camera chips, “microcameras”, on the same substrate as microLEDs as part of the display manufacturing process (see diagram below for an illustration of the concept). Advanced real-time image processing is used to form high-resolution video by combining lower resolution video streams from multiple microcameras.

Because of the recent increased attention to improving the videoconferencing experience and the ongoing drive to eliminate bezels and display cut-outs in mobile phones and other devices, interest in including image capture inside displays is growing rapidly. The number of technical papers presented at Displayweek related to including image capture inside the display grew from essentially zero in 2019 to eleven in 2021. So far, under-screen or under-display cameras have been demonstrated in mobile phones with OLED displays, but only one brand is actually shipping and the tradeoffs in image quality and visibility of the camera zone have been noted.

Researchers from Korea's Electronics and Telecommunications Research Institute (ETRI) developed a new process to produce microLED displays, which they say can be highly cost effective.

The new process is based on a novel film-like material developed at ETRI, called SITRAB. Using lasers, the process apparently detaches the microLED from the original epiwafer and bonds it to the SITRAB film in the same process step. The LEDs are then transferred to the final target backplane.

Apple's latest iPad Pro tablets use a mini-LED backlit LCD (which Apple refers to as Liquid Retina XDR). While most reviews of the new display are quite positive, some users are complaining of "blooming" - the edges of bright objects on dark backgrounds tend to 'bleed' as the dimming zone is not small enough.

miniLEDs improve over LCD as they introduce thousands of dimming zones, which increases contrast and improves power consumption. The dimming zones, however, are sometimes not small enough, as some users find out, and cannot compete with an emissive technology such as OLED or microLED.

China-based display maker Royole introduced a stretchable and transparent microLED display prototype at SID Displayweek 2021. The company says that this display, the first of its kind, is compatible with existing industrial manufacturing processes.

The prototype panel is a 2.7-inch 96x60 display (120 PPI) . It can stretch by up to 130% and bend up to 40 degrees. It is quite transparent, too - with a transmittance of 70%.

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.

Vuzix have officially launched its microLED display engines, based on three JBD monochrome microLED microdisplays.

Vuzix says that samples of the new engines are now available upon request. These are monochrome devices, and one would have to use three (red, green, and blue) for a full color display. Vuzix is developing full-color and higher-resolution (HD) engines. Vuzix says that its next-generation smart glasses will adopt these devices which are now on offer to customers.

MicroLED developer PlayNitride introduced interesting new display prototypes at SID Displayweek 2021.

The first display is a 89-inch 5K (59 PPI) curved display, produced from tiled microLED panels. The display has a 32:9 aspect ratio with the microLEDs driven by PCB. The 89-inch display is build from 168 tiles, and it achieves a brightness of over 2,000 nits.

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.