Mini-LED, Micro-LED and OLED displays: Present status and future perspectives

July 12, 2020

Display technology has become ubiquitous in our daily life; its widespread applications cover smartphones, tablets, desktop monitors, TVs, data projectors and augmented reality/virtual reality devices. Presently, liquid crystal displays (LCDs) and organic light-emitting diode (OLED) displays are two dominant flat panel display technologies. Recently, inorganic mini-LEDs (mLEDs) and micro-LEDs (μLEDs) are emerging offering ultrahigh luminance and long lifetimes, that can significantly enhance the dynamic range of LCDs or work as sunlight readable emissive displays. Nevertheless, challenges such as mass transfer yield and defect repair remain, which will undoubtedly affect the cost. "LCD, OLED or μLED: who wins?" has become a topic of heated debate.

In a new paper published in Light: Science & Application, a team of scientists, led by Professor Shin-Tson Wu from the College of Optics and Photonics, University of Central Florida, USA have conducted a comprehensive analysis on the performance of mLED/μLED/OLED emissive displays and mLED backlit LCDs. This group evaluated the power consumption and ambient contrast ratio of each display in depth and systematically compared the dynamic range, motion picture response time, color gamut, and adaptability to flexible and transparent displays. The pros and cons of mLED, μLED, and OLED displays are analyzed, and their future perspectives are discussed.

Prof. Wu's research group has been working on display technologies for decades, from conventional LCDs, OLED displays, quantum dots, to the emerging mLED and μLED displays. This team is devoted to discovering new display materials and devices. "Each display technology has its strengths and challenges: conventional LCDs have long lifetime and low cost, but their contrast ratio and flexibility are limited. OLED displays offer unprecedented dark state and ultrathin profile, but their lifetime and burn-in issues remain to be overcome. Lately, mLED/μLED displays are promising to provide high luminance, long lifetime and compatibility to flexible and transparent displays, but the chip size effect leads the performance on high-resolution-density augmented reality/virtual reality displays to a question, not to mention the low manufacturing yield and high cost. Technology development and manufacturing readiness fall years behind a new method springs. Our motivation is to understand the fundamental limits and develop new approaches for each technology to overcome its obstacles."

"There are several important performance metrics considered: (1) a high dynamic range and a high ambient contrast ratio, (2) high resolution or high ppi to minimize the screen-door effect, (3) a wide colour gamut, (4) a wide viewing angle and an unnoticeable angular colour shift, (5) a fast motion picture response time to suppress image blur, (6) low power consumption, which is particularly important for battery-powered mobile displays, (7) a thin profile, freeform, and lightweight system, and (8) low cost.

"After investigations, we found all of these display technologies support superior performance in the abovementioned criteria except for several trade-offs: (1) In achieving high luminance for HDR, mLED-LCDs require careful thermal management, and OLED displays would compromise the lifetime. (2) Transparent display is not the best stage for non-emissive LCDs. (3) The power efficiency and ambient contrast ratio depend on the mLED/μLED/OLED chip size. To achieve the same ambient contrast ratio, mLED backlit LCDs require a comparable power consumption with OLED displays, while the polarizer-free mLED/μLED emissive displays could be 3× more efficient." the scientists summarized.

"In the upcoming years, OLED would continue to grow in smartphone market, while mLED backlit LCD would penetrate into tablets, gaming monitors, computers, and TVs, as the technology gradually matures. In the not-too-distant future, mLED/μLED emissive displays could gradually move toward the central stage as their cost becomes more acceptable." the scientists forecast.
-end-


Light Publishing Center, Changchun Institute of Optics, Fine Mechanics And Physics, Chinese Academy

Related Technology Articles from Brightsurf:

December issue SLAS Technology features 'advances in technology to address COVID-19'
The December issue of SLAS Technology is a special collection featuring the cover article, ''Advances in Technology to Address COVID-19'' by editors Edward Kai-Hua Chow, Ph.D., (National University of Singapore), Pak Kin Wong, Ph.D., (The Pennsylvania State University, PA, USA) and Xianting Ding, Ph.D., (Shanghai Jiao Tong University, Shanghai, China).

October issue SLAS Technology now available
The October issue of SLAS Technology features the cover article, 'Role of Digital Microfl-uidics in Enabling Access to Laboratory Automation and Making Biology Programmable' by Varun B.

Robot technology for everyone or only for the average person?
Robot technology is being used more and more in health rehabilitation and in working life.

Novel biomarker technology for cancer diagnostics
A new way of identifying cancer biomarkers has been developed by researchers at Lund University in Sweden.

Technology innovation for neurology
TU Graz researcher Francesco Greco has developed ultra-light tattoo electrodes that are hardly noticeable on the skin and make long-term measurements of brain activity cheaper and easier.

April's SLAS Technology is now available
April's Edition of SLAS Technology Features Cover Article, 'CURATE.AI: Optimizing Personalized Medicine with Artificial Intelligence'.

Technology in higher education: learning with it instead of from it
Technology has shifted the way that professors teach students in higher education.

Post-lithium technology
Next-generation batteries will probably see the replacement of lithium ions by more abundant and environmentally benign alkali metal or multivalent ions.

Rethinking the role of technology in the classroom
Introducing tablets and laptops to the classroom has certain educational virtues, according to Annahita Ball, an assistant professor in the University at Buffalo School of Social Work, but her research suggests that tech has its limitations as well.

The science and technology of FAST
The Five hundred-meter Aperture Spherical radio Telescope (FAST), located in a radio quiet zone, with the targets (e.g., radio pulsars and neutron stars, galactic and extragalactic 21-cm HI emission).

Read More: Technology News and Technology Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.