From 1999 to 2019, micro LED has experienced 20 years of innovation. Only in recent years, it is no longer low-key: the mysterious black technology from the shelf seems to have finally come to the door of commercialization.
However, today, there are n answers to the definition of micro led in different players and application fields.
Different definitions of micro LED
Some are defined as real micro led according to the size of LED chip < 100 / 50 μ m; some are based on the chip area < 2500 μ m2; some are based on the pixel spacing < 0.5mm; others are judged by whether the chip has substrate finally.
From the point of view of easy technology iteration, upstream and panel displays prefer to define Mini led and micro led from chip size, forward flip and thin film transfer (substrate removal); from the perspective of easy understanding of large screen display application side, midstream and LED displays tend to define Mini led and micro LED (screen) with pixel spacing (pitch).
For example, in the field of large screen display, leader enterprises of LED display, liad and Leiman optoelectronics, respectively, announced “8K micro led high-definition display with 0.6mm micro spacing”, emphasizing the realization through flip chip cob key technology.
The p0.6 micro led ultra high definition display panel based on flip chip cob technology exhibited by Leiman Optoelectronics in ise, the Netherlands
Before the formation of industry standards, although different players have different understandings of micro led in various application scenarios, they all have a common feature that they strive to express – innovation of visual experience. The core purpose of this paper is not to entangle the definition of micro led, but to explore why self luminous miniaturized LED display may be the ultimate display technology. Because the core of this paper is not backlight, this paper uses micro led to represent the miniaturized LED technology of self luminous.
So, back to today’s topic, why do leading companies such as Ryad and Lehman optoelectronics, which used to be the technology leaders in the field of self luminous large screen display, or apple, Sony, Samsung and other international famous enterprises adopting LCD and OLED, dare not relax in their exploration of micro LED technology, hoping to accelerate the breakthrough in micro LED technology LED technology bottleneck, let human enjoy better visual experience faster?
Inherent advantages of micro LED
From the perspective of large screen display, if small spacing makes LED display screen from outdoor to indoor, micro LED is a revolutionary technology that can bring the concept of small spacing into ultra high definition market and consumer electronic application, and let LED display enter into the to C consumer market from public display to television.
From the perspective of small and medium size, micro LED can also enter mobile phones, watches, VR / AR applications with higher requirements for size and PPI. Different application scenarios will be dominated by players from different camps. The most fascinating thing about new technologies is that they can restructure the industrial chain, which means that they can give each camp an opportunity to reshape their brand pattern.
In the past, any display technology competition was in these areas: color gamut, power consumption, thickness, response time and life; in the future, display technology will also compete to see if additional functions such as sensing can be integrated into the display panel.
As mentioned above, micro LED technology will help expand into the consumer market. Let’s take a look at the consumer display market. The reason why LCD can stick to the wall for more than ten years is related to the fact that it has two knives that unify the world, one is “image quality”, the other is “application scope”.
However, if LED backlight in the way of LCD, continue to be a hero behind the scenes, there are still several limitations. Let’s take a look at the views of Mr. Zhang Jiahong, research director of the research center and the first batch of micro led research analysts on both sides of the Taiwan Strait, who are experts
Huge cost of efficiency. The method of LCD + LED is to change “point light source” into “area light source”, and then back to “point light source”. Finally, only 6% – 8% is left. This is an obvious detour. The complicated optical design is derived. The light guide plate, lens and optical diaphragm are all used to realize uniform surface light source. In the final analysis, the surface light source does not need to exist and will not exist in the end.
The tortuous road of color. At present, white LED is used for backlight, and color filter (CGF) is used to realize full-color of liquid crystal. The color of light starts from blue light chip. First, phosphor is mixed into white light, and finally through color resistance. This is equivalent to changing into three primary colors in an extremely inefficient way.
Excessive industrial division of labor. Backlight and LCD need more complicated division of labor and longer industrial chain. In order to solve the additional problems derived from imperfect technology, self illumination such as micro LED can smooth and converge the industrial chain and reduce the inefficiency caused by “excessive industrial division”, which includes huge management costs and communication costs.
Therefore, rather than say that the next generation of LCD display technology is OLED, micro LED or quantum dots, it is better to say for sure that the next generation display technology after LCD must be self luminous. OLED is the most powerful and the first to appear, but it only performs well in the field of mobile phones, because it has several fatal short boards, namely, life span, large size bottleneck and stability; qled is still in the early stage of development due to its poor blue light efficiency, so it can only improve the color performance of other technologies first LED is expected to perform well this year due to its low power consumption, high brightness, ultra-high resolution and color saturation, faster response speed, longer service life and higher efficiency. Although the process technology is not yet mature, the improvement of yield and efficiency is relatively visible. Compared with other technologies in the material congenital defect system problems, micro Led bottleneck is obviously easier to break through.
Pull back to see the application market of large screen display.
In recent years, the market share of small spacing LED display has soared. With the emergence of this technology, China has become the first country worthy of LED display. Both the strength of manufacturers and the overall volume are at the top of the world.
And the concept of small spacing in the most straightforward way, the most intuitive feeling is to improve the quality of the display screen, even if you watch closely, there will be no mosaic feeling. The technology behind this is based on the reduction of pixel spacing and the reduction of LED chip synchronization, which can be defined as the prototype of micro led. Most of the opportunities brought by small spacing are indoors. High quality and seamless splicing of large screen can bring more amazing effects to commercial applications such as advertising and exhibition, and even consumer application market. China, as the largest display screen manufacturer, naturally has no reason to miss the wave of micro led.
When micro LED technology is used in the display, it not only has excellent performance in brightness, resolution, color gamut, reaction speed and service life, but also can get close to the frameless viewing angle because there is no backlight, color filter and other structures mentioned above. The screen accounts for 99.99%, and the appearance and display effect are more amazing.
In addition, it is worth mentioning that, with the opening of 5g era, 4K TV will become more popular, and 8K TV also begins to come to us. 4K and 8K TVs put forward higher requirements for resolution, and also call for the emergence of larger Ultra HD large size, seamless splicing panel. Samsung, Sony, and Lehman (which have chosen cob solution by coincidence) have successively released micro LED display products are also emerging.
Note: the resolution and corresponding size of p0.6 micro LED display based on flip chip cob Technology
More importantly, when the micro LED is small enough, the display backplane will have the opportunity to gain more space. Taking advantage of the core competitiveness of low pixel area, on the one hand, it can greatly improve the visual experience such as contrast (for example, Sony micro LED of P1.2) On the other hand, if we can integrate multiple functions, such as floating touch, holographic projection, or gather more sensors and solar panels, it will bring revolutionary experience.
To sum up, micro led, the light source, is the only self luminous display technology that does not need to fill the display interface with pixels. With the super long life and high efficiency, it can not only fully meet the competition of traditional display technology in color gamut, life, power consumption, contrast and other traditional indicators, but also lead multiple positions in the future when the display technology needs to integrate other interactive functions.
Because of other self illumination, micro LED can basically realize, but other display technologies that micro LED can realize are not necessarily. Therefore, in the visible future, micro LED will be the ultimate display technology as long as it can continue to invest and make technological progress and continuously reduce the effective market cost in the window period.