A MicroLED is a next-generation flat-panel display technology that is based on an array of microscopic light-emitting diodes that form individual pixels. It is also one of the few examples of a self-emissive display technology with characteristics and advantages that are similar to organic light-emitting diode or OLED display technology.
The technology was first invented in 2000 by a team of researchers spearheaded by Hongxing Jiang and Jingyu Lin while they were at Kansas State University. Sony Corporation demonstrated the first MicroLED panels before the public in 2012. Plans to commercialize the product did not materialize because of the high production costs.
Several barriers to production and technological requirements prevent commercialization. There was a need to develop and discover more innovations to advance the underlying technologies, improve production efficiency, and drive down manufacturing costs. Several companies have introduced conceptual products since then.
It was Samsung showcased a 146-inch MicroLED panel called The Wall during the Consumer Electronics Show in 2018. LG Electronics demonstrated a 173-inch MicroLED panel during the IFA 2018. The Crystal LED Display from Sony became available in September 2019 while Samsung announced that it began shipping The Wall in October 2019.
More manufacturers are looking forward to developing MicroLED display technology due to its comparable advantages that can rival OLED display technology and superior edge over LCD technologies. Apple started developing its implementation in-house in 2018 and would feature panels based on MicroLED on future generations of its devices.
Pros: Advantages MicroLED Display Technology and Notable Applications
Several industry analysts and technology enthusiasts believe that MicroLED would become a next-generation technology that could compete head-on against or totally replace IPS LCD and OLED display technologies because of their inherent characteristics and feat.
Remember that this display technology involves using microscopic light-emitting diodes and fitting them into a single pixel. The fact that these diodes are self-emissive or emit both light and color means that there is no need to use backlighting.
Nevertheless, one of the primary selling points and thus, advantages of MicroLED is that it has the endearing characteristics of OLED minus its notable drawbacks associated with its shorter lifespan due to screen burn-in and limited brightness.
1. Shares the Same Benefits or Advantages of OLED and other Emissive Display Technologies
OLED has become a preferred choice among manufacturers and consumers since 2008. The appearance of AMOLED panels in devices such as the Galaxy line of smartphones from Samsung and the smart TV sets from LG Electronics proves this point. Improvements in production processes have driven down its manufacturing costs and made it available even in several mid-range and entry-level product categories.
There are several reasons to choose OLED over in-plane switching or IPS LCD technology. These include an almost infinite contrast ratio. Higher native pixel response time, wider viewing angle, and better energy efficiency. The arrival of plastic OLED and flexible OLED products has also resulted in the development of devices with novel form factors. Examples include curved monitors, foldable smartphones, and edge-to-edge panels.
It is important to highlight the fact that OLED panels and even experimental newer-generation panels based on quantum dot technology are self-emissive. This means that both light and colors are emitted from the individual diodes unlike in conventional LCD panels that require backlighting for colors emitted from the crystalline materials to become visible. MicroLED shares this same mechanism and self-emissive characteristic.
The individual diodes in an emissive panel can be switched on and off. This provides a wider contrast ratio from the production of deeper and more natural blacks and brighter whites. The localized dimming and better control over individual pixel switching allow better color control and more accurate image representation. An LCD can have better color control but it cannot produce deep blacks because of the light leakage from the backlighting.
2. Addresses the Drawbacks or Limitations of OLEDs while Competing with IPS LCD Technology
OLED is superior to IPS LCD on paper. IPS LCD panels are still popular because of their unique advantages. Some manufacturers and consumers still prefer it because of the two main drawbacks of OLED panels. These are their shorter lifespan due to the faster and uneven degradation of organic diodes, greater susceptibility of these organic materials to water damage, and higher production costs that translate to high end-user prices.
Take note that another notable advantage of MicroLED is that it does not have the drawbacks or disadvantages of OLED. Remember that it is based on using inorganic light-emitting diodes. These materials are more durable and the degradation rate of each is almost uniform. Hence, from a consumer standpoint, devices equipped with MicroLED panels have a longer lifespan and provide better value than counterparts equipped with OLED panels.
Another advantage of microLED over OLED is its lower power draw. It can be driven using smaller components or chips while OLED requires larger components to achieve a longer lifespan and better luminance. It also has better brightness. An OLED can have a peak brightness of around 1500 nits while a MicroLED can achieve a general brightness of around 4000 nits that can peak further to 10000 nits through better engineering and driving.
It is also worth mentioning that this emerging display technology can support thinner panels that can be fitted in frames with minimal or negligible bezels. Adding to this is its wide viewing angle that outperforms an LCD panel. It also supports modularization. These characteristics have made OLED popular in modern consumer electronic devices such as premium smartphones and smart TV sets and make MicroLED a more feasible alternative.
Cons: Disadvantages of MicroLED Display Technology and Notable Issues
1. Challenges in Manufacturing Processes, Costs, and Mass Production
The working principle behind MicroLED is straightforward. It involves the use of small-sized light-emitting diodes to form individual pixels. However, while this sounds simple on paper, the processing can be challenging. The main challenge centers on the miniaturization of the diode down to the microscopic level. This has become achievable but mass production is limited because it remains expensive than the process used in manufacturing LCD panels.
It would be difficult to shrink a particular LED without compromising its performance. Doing so would mean reducing the luminance of light it produces. Solving this trade-off between size and performance would require driving the diode further or making it more efficient at producing light. Additional driving would translate to higher power consumption and would produce more heat. Making them more efficient means introducing new technologies and processes.
Another issue is the need to address the gaps or pitch size between microscopic light-emitting diodes and the pixels. It is important to highlight the fact that there is a limitation in how much electrical circuits and other components can be made small. This is another miniaturization problem. The current conventions in circuit design and engineering are still leaning toward larger and macroscopic electrical circuits and other hardware components.
The production of microscopic light-emitting diodes in large volumes is also a notable issue or disadvantage of MicroLED mass production. Manufacturers need to ensure that there is no variation in the brightness of each diode and that assembling them is in perfect alignment to produce a uniform performance. Take note that producing a particular MicroLED panel with a 4K resolution would require 25 million microscopic light-emitting diodes.
2. LCD Based on Mini-LED is a More Practical Alternative to Emissive Displays
Manufacturing issues translate to higher production costs. The costs can be passed down to consumers through higher pricing but this would limit market reach. This provides a lesser economic incentive for manufacturers and discourages overall market appeal. Hence, based on this, another disadvantage of MicroLED is that it is impractical for mass production and wider mass consumption. This limits its application to expensive devices.
IPS LCD and OLED are the more feasible alternatives. Several manufacturers have also positioned LCD panels with Mini-LED backlighting as the better and more practical alternative. Mini-LED is not a display technology but a backlighting scheme used in LED-backlit LCD technology. It involves the use of small-sized light-emitting diodes to illuminate an LCD panel to improve local dimming capabilities and improve the contrast ratio and color reproduction.
Nevertheless, based on its principles, Mini-LED inherits the advantages of LCD while also addressing some of its disadvantages. It can rival and even outperform OLED and MicroLED. For example, when used as a backlighting scheme for an in-plane switching or IPS LCD, it can provide deeper and more natural blacks for a better contrast ratio, make color reproduction more accurate, and improve brightness for superior outdoor visibility.
It is still worth mentioning that consumer electronic companies such as Apple are still banking on commercializing MicroLED and making it available in mass-produced devices. Most devices such as laptops, monitors for desktop computers, smartphones and tablet computers, and television sets are still based on either LCD technologies or OLED. There is also an emerging market for quantum dot display panels from manufacturers such as Samsung.
Rundown: Summary of the Advantages and Disadvantages of MicroLED
Below are the advantages of MicroLED display technology:
- It is a self-emissive display that does not require backlighting, thus producing a considerably even brightness across the screen.
- Pixels can be turned on and off individually to produce deep blacks and a wider contrast ratio similar to OLED display panels.
- Better color control, more accurate image representation, and possibly better refresh rate because each pixel can be controlled individually.
- General brightness is around 4000 nits, but future iterations can produce a brightness of up to 10000 nits through better engineering.
- Has a longer lifespan than OLEDs or in other words, it does not suffer from screen burns due to different degradation rates of pixels.
- It can support thin panels, thin to zero bezels with wide viewing angles, and modularization to make it a universally applicable display tech.
Below are the disadvantages of microLED display technology:
- There are manufacturing challenges needed to overcome to commercialize and produce MicroLED panels for the mass market.
- Costs remain high due to the manufacturing challenges, thus making LCD and OLED technologies more economical.
- There is also a need to resolve the issue related to pitch size and the introduction of new conventions in circuit design and engineering.
- Consistency in producing millions of microscopic diodes and assembling them in a single display panel should also be addressed.
FURTHER READINGS AND REFERENCES
- Horn, R-H., Chien, H-Y., Trantair, F-G., and Wuu, D-S. 2018. “Fabrication and Study on Red Light Micro-LED Displays.” IEEE Journal of the Electron Devices Society. 6: 1064-1069. DOI: 1109/jeds.2018.2864543
- Huang, Y., Hsiang, E-L., Deng, M-Y., and Wu, S-T. 2020. “Mini-LED, Micro-LED, and OLED Displays: Present Status and Future Perspectives.” Light: Science & Applications. 9: 105. DOI: 1038/s41377-020-0341-9
- Konsyse. 2020. “Difference Between Micro-LED and miniLED.” Konsyse. Available online
- Moore, S. K. 2019. “microLED Displays Expected in 2020: The Last Remaining Hurdle is Mastering Mass Production.” IEEE Spectrum. 56(8): 8-9. DOI: 10.1109/MSPEC.2019.8784111
