With the improvement of people’s requirements for picture quality, smaller and smaller display screens have become the focus of more and more people’s attention. For example, the mini LED display screen that has been talked about in recent years is one of them.
Mini LED displays and small-pitch LED displays always look somewhat similar, so what’s the difference between small-pitch and mini?
Small pitch LED, a very historic product
It is impossible to verify how long the small-pitch LED products have appeared. This time period is at least 10-15 years old. Among them, the large-scale popularity of such products is only about 5 years old.
Within the industry and most industry data research institutions, P2.5 and below products are regarded as “small-pitch LEDs”. This pixel pitch metric also has a clear “display system meaning”. That is, a 100-inch screen can accommodate 800*600 resolution content point-to-point.
For a 4:3 ratio display system, the 100-inch format is 2.03 meters wide and 1.52 meters high; for a 16:9 ratio screen, the 100-inch format is 2.15 meters wide and 1.35 meters high. About 15 years ago, high-definition content and standards were not rich enough, including indoor and outdoor “not very large-sized LED advertising screens, mainly using 4:3 content of 800*600 size”. Therefore, products that carry this content clarity have conventionally become the starting point of “small-pitch LEDs”.
However, with the development of technology, the small-pitch LED technology continues to improve, the spacing continues to shrink, and the definition of video content continues to improve, so that today’s 4K/8K ultra-high-definition concept, people’s psychological “small-pitch” concept standard is also Continuous improvement – many manufacturers have raised the entry threshold for small pitch to 2mm pitch or 1.8mm pitch: the visual implication is that 100 inches can carry high-definition quality content point-to-point.
Even for home-oriented LED display large-screen products, the starting performance has required a 100-inch 4K display, that is, the pixel pitch is around P0.5. Therefore, what kind of product is a small-pitch LED is a concept with rich historical connotations, and it is also a concept that is constantly changing with technological upgrading, and it is also a concept that is closely related to specific applications and scenarios.
Of course, as a research institution, it is necessary to adhere to the P2.5 standard; however, in the era when P1.0 has made a comprehensive breakthrough, it is necessary to further research the standard subdivision, such as the “fine pitch” concept proposed by some manufacturers. reality based.
Mini-led concept, transitional definition standard
The pixel pitch of the LED display keeps getting smaller and smaller, and the size of the LED crystals used must also keep getting smaller – however, it is obvious that the smaller LED crystal particles are packaged and integrated with “more finer” and “technical content” “Higher jobs.
“Appropriate pixel pitch, appropriate process maturity, and appropriate LED crystal particle size.” The three “appropriateness” have become the key basis for the birth of the mini-led concept. In other words, for display systems, especially products below P1.0, from the perspective of luminous brightness requirements, almost all 10-micron LED crystal particles can meet the requirements.
However, considering “the particularity and difficulty of the integration process”, LED screens with a P1.0 pitch, currently using 200-300 micron LED crystal particles, are temporarily the “best” choice.
And this is smaller than the traditional LED crystal particles, but it is not the “extremely tiny” LED crystal particle size, it becomes the concept of mini-led. Specifically, it mainly refers to products with LED crystal particle size in the range of 100-300 microns. In theory, these LED crystal particles have been able to manufacture small-pitch LED display products with P0.4-P1.2 specifications. ——Of course, products with larger spacing can also apply mini-led technology.
At the same time, mini-led technology has another connotation: a new backlight source in the era of HDR display on LCD screens. As a liquid crystal backlight, LED arrays do not require very high particle densities, but do require somewhat higher brightness levels. For example, 8K TVs may have less than 10% efficiency from the backlight to the screen brightness, and the backlight brightness needs to be more powerful. At this time, too small LED crystal particles are not competent, but mini-led technology is better.
However, as a backlight application, mini-led also has a special field: that is, to provide backlight for LCD screens such as mobile phones and smart watches, it still requires smaller LED particle size. In these product areas, whether it is mini or micro requires specific product analysis.
To sum up, the use of mini-led technology has considerations of “process maturity and difficulty”, as well as “point luminous intensity requirements”, and it is also related to the pixel pitch of the display screen or array structure. At the same time, mini-led products can also use technologies such as all-in-one packaging (such as the four-in-one packaging popular in 2018) to achieve “maximum potential and efficiency” of the traditional surface mount process system.
Because the LED crystal particles of micro-led products are very small, and the pixel pitch of the final product is also very small (not larger than 1 mm, or even tens of microns), micro-led display technology can hardly inherit the existing packaging, testing, Maintenance and complete machine manufacturing technology.
That is, the surface mount LED technology has been completely replaced by the “mass transfer” technology that belongs to the micro era: in comparison, mini-led can use the mass transfer technology, or the four-in-one package + surface mount technology.
Therefore, micro technology, from the final product form (one-inch or even smaller ultra-clear display products to 200-inch large screens), and the process technology system (high-precision mass transfer has become a must-have technology) “completely changed the LED. Show” the historical aspect. It is a display technology that truly opens a new era. And in the context of the continuous maturity of micro technology, the necessity of mini-led products will drop significantly.
On the whole, the rise and replacement of concepts such as small pitch and mini reflects the improvement of the fineness of LED display products and the continuous “miniaturization” of the corresponding LED crystal particle size; and brings continuous progress in the main processes of the industry: from direct insertion to table Paste to the mass transfer; even bring other key material progress, such as the continuous upgrading of industry technology such as glass substrate TFT to replace PCB printed circuit.
At the same time, this progress has also greatly broadened the application scope of LED display, from the earliest simple outdoor advertising, to indoor high-quality and fine display, and even today’s TV color TV products, future VR, smart watch or smartphone screen applications, etc. , creating a space for the continuous growth of the industry and bringing huge wealth opportunities in the LED industry.