The Roadmap Ahead for Micro-LEDs is Anything But SmallSeptember 14, 2020 by Jake Hertz
Micro-LEDs open doors for display technology to be twisted and folded—all while providing higher resolutions than existing LCDs or OLEDs.
Display technologies are some of the most prevalent electronic equipment in the world today. Almost every consumer device, from smartphones and cars to refrigerators and thermostats, has some sort of display technology. This popularity has pushed researchers to constantly look for ways to improve and expand on existing technologies.
One such example comes from the University of Texas at Dallas, where researchers developed flexible micro-LEDs that can be folded, cut, and attached to surfaces—a possible breakthrough for wearable displays.
A flexible micro-LED that can be folded and twisted. Image used courtesy of the University of Texas at Dallas
How did micro-LEDs and related research rise to such popularity in the past few years?
Trends in Display Technologies: From LCD to OLED to Micro-LED
In recent years, there has been a gradual shift from LCDs to OLED displays. OLEDs improved LCDs because of their emissive displays, superior dark state, thin profile, and freeform factor—enabling technologies such as foldable electronics.
Yet, OLEDs are not a perfect solution; they're made with organic compounds, making them expensive to develop, somewhat limited in brightness, and potentially susceptible to burn-in. On top of this, they're also very difficult to manufacture in large sizes.
Foldable device using OLED display technology. Image used courtesy of OLED-Info
Now with emerging technologies such as AR, VR, and wearables, the future of display technologies looks more important than ever. As such, engineers are looking to a new form of display technology to meet their needs: micro-LEDs, sometimes referred to as uLEDs.
What Are Micro-LEDs?
First invented by Hongxing Jiang and Jingyu Lin of Texas Tech University, micro-LEDs work just like a regular LED by converting electrical energy into light. The obvious distinction between the two is that uLEDs are microscopic versions of an LED without a package.
Driving circuit for a full-color micro-LED display. Image used courtesy of Applied Sciences (PDF)
uLEDs commonly measure less than 50 μm, which can be 1/100 the size of a conventional LED.
The Advantages and Challenges of Micro-LEDs
Thanks to their small size, multiple uLEDs can fit in one pixel, producing a much better picture than traditional technology.
Inventor Hongxing Jiang explains, “For the next generation microLED large TVs, you have millions of tiny pixels... Each pixel comes with three microLEDs, one blue, one green, and one red."
RBG micro-LED full-color display. Image used courtesy of Applied Sciences (PDF)
He continues, "Because they're so tiny, they can give you a very high resolution and contrast, leading to more beautiful images. They're also very bright, and the dark areas are really dark. In the old technology, the dark areas of a display are not really as dark because some light still leaks through.”
Micro-LEDs also benefit from the fact that, like OLED displays, they’re self-emissive (PDF), meaning they don’t require a backlight. However, in contrast to OLED displays, uLED displays are not susceptible to burn-in. uLEDs are also slimmer and less expensive since they are not made from organic compounds.
In theory, a display using uLEDs provides more color and higher brightness with lower power than today’s OLED displays. Still, uLEDs' small size is both an advantage and a challenge: a benefit because of the incredible resolution it provides and a limitation because they are difficult to implement.
Booming Promise for Display Technology
Forecast of micro-LED displays. Image used courtesy of Applied Sciences (PDF)
While the challenges to overcome are certainly prevalent, micro-LEDs are poised to become a considerable contender in groundbreaking display technologies. Applications like AR, VR, wearables, smartphones, smartwatches, and TVs will undoubtedly benefit from further uLED development.