Micro LED is almost impeccable in terms of performance, but the current situation of display technology still has many difficulties. Micro LED still has a long way to go. I also believe that with the passage of time, Micro LED may become the end of all display technologies.
As early as 2014, Apple acquired LuxVue Technology, a micro company that mainly develops Micro LED. Since then, Micro LED displays have gradually entered the field of vision of the general public.
LED display screen has the advantages of high brightness, single-point controllability, full color, energy saving and environmental protection, and long life. It is also the only display technology that can be used outdoors today. Judging from the existing panel display technology, Micro LED has very obvious advantages.
The biggest problem with LCD displays is that they are not bright enough and are not suitable for outdoor environments. The second is that liquid crystal technology is difficult to enlarge the display area, and the splicing of LCD units will produce very obvious seams. The LED display screen has high natural brightness and is very suitable for use in outdoor environments; the LED display screen can be infinitely spliced, and no matter how large the display area is, it is not a problem. At the same time, the power consumption of LED display is only one-tenth of that of liquid crystal LCD, and the energy saving effect is obvious.
Compared with organic OLED display technology, because LED is inorganic, its service life will be longer. At the same time, its power consumption is half that of OLED, and the outdoor display effect is better. Micro LED can also be made into flexible and bendable surfaces like OLED.
More importantly, Micro LED can also have both light-emitting and sensing capabilities. In other words, it can also integrate the function of a sensor. Therefore, there is still a lot of room for imagination in the application of Micro LED.
From the current point of view, the performance of Micro LED is almost impeccable and has the advantages of all display technologies.
The chip size used in our LED displays, including the smallest small-pitch displays, is approximately 100μm or more. Micro LED chips require a completely different production technology from current chips, and the smallest size can be several μm. The industry has not yet finalized a clear definition of the size of Micro LED chips. Most people believe that the chip size must be at least less than 50μm before it can be called Micro LED technology.
The most critical steps in the above figure are the first and second steps.
The first step is the miniaturization process of LED chips. There are currently three technical approaches to achieve microprocessing: Chip Bonding, Wafer Bonding, and Thin film transfer. But only the latter two can achieve massive transfers.
Through the wafer shrinkage process, there are many technical levels in the industry that can achieve 50-100μm chips. Sony's CLEDIS chip size reaches 20μm, while Apple's technology level is 10μm. In addition, in the laboratory, 3μm or even 1μm has been successfully achieved.
The second step is mass transfer technology. How to transfer a huge number of micron-level chips to the circuit substrate is also the biggest technical bottleneck of Micro LED at present. Mass transfer technology involves the precision of production equipment, process yield, output speed, accuracy and stability of testing equipment and instruments, defective pixel repair methods, reduction of process processing costs, etc. The industries involved span the upstream and downstream supply chains of LED, semiconductors, and panels, and the technical threshold is quite high.
For example, regarding output speed. The die-bonding machine currently used to manufacture traditional LED displays can mount 1 to 10 LEDs on the substrate per second. It takes more than 30 days to produce a 100-inch display with full HD 2 million pixels through the current method. Therefore, if the current chip placement machine is used to produce Micro LED, the production capacity is almost unimaginable. The Korea Machinery and Materials Research Institute has developed a patented scroll technology. This rolling transfer process can transfer more than 10,000 LEDs per second, and the entire process can be completed within an hour.
It is true that Micro LED still has a long way to go. In addition to the mass production process challenges mentioned above, the consistency of the chip itself and how to repair it are still problems that need to be solved. Sony turned to applying this technology to large screens because it encountered huge difficulties in developing Micro LED TV applications.
The exploration of Micro LED technology is currently limited to very small area display requirements, such as watches, mobile phones, wearable devices, etc. The research and development of micro-pitch technology has given birth to Mini LED technology. Its chip size is approximately between 50μm and 100μm. Applications that can be expected in the short term include TV backlights and automotive lighting.
The research and development of Micro LED display technology has brought together many traditional and start-up technology companies around the world. It is no exaggeration to describe its technological development as changing with each passing day. Given time, Micro LED may eventually become the end of all display technologies.
ANNA