OLED Panel Printing Out OLED Popularization Is A Key Step
- Apr 19, 2018 -

                

LG and Samsung will invest in building a "Printed OLED" panel demonstration line in 2017. If this plan is implemented, this will be a key step towards the large-scale adoption of OLED...

However, wait! Why did you come up with something new called "Printed OLED"? Is this a new display technology? In the past five years, the OLED "It's Coming Soon" declaration has heard a long scorpion! Can we still believe this news? And with new technologies, what are the original production lines and the production lines currently under construction?

There are too many problems! However, let's take a look at what the latest news says: According to Korean media reports, Samsung Display and LG Display are preparing to go through equipment factories with Kateeva and Tokyo Electron, and Material companies such as Merck and Idemitsu Kosan have cooperated to introduce inkjet printing processes on A3 and M2 production lines. The timetable is 2017.

Among them, the Samsung A3 production line is the 6th generation line, the target product is a flexible OLED, the size of the monthly input substrate 15,000; LG M2 line is the 8.5 generation line, the target product rigid OLED, the current technology is white light oled + color filter film, full width steam Across, the scale of the monthly substrate is 26,000. Samsung A3 is the world's first pure flexible OLED line, which is mainly used for small and medium-sized applications such as mobile phones and RGB oled products. LG M2 is the world's first large-scale OLED production line, and is mainly used for large-size applications such as TV. ——These two lines are the most advanced flat panel display panel production lines!

According to media reports, Mitsubishi Chemical has already provided samples of "OLED materials" for inkjet printing to several potential users in the first half of this year; domestic TCL-led Juhua Printing also signed printing display material products with Germany Merck and others. Cooperation agreement.

In summary, it seems that "printing" + "OLED" has become the "core direction" of the new-generation flat panel display technology in the first half of the year. However, I believe many people have a question: Now that there is a large-to-small OLED production technology, why is printing technology so popular? There are four reasons for this:

First of all, printing is a low-cost way. Just OLED material itself, using the printing process than the current steaming process to save 90%.

Secondly, although the steaming process solved the entire steaming problem from the 3rd generation line to the 8.5th generation line, it failed to realize the RGB triple primary evaporation in large size. The existing 8.5-generation steam-evaporation process significantly reduces the yield of RGB OLED three-color panels.

Third, the two processes of steam distillation and inkjet printing have significantly different effects on the life characteristics of OLED materials, and the latter is beneficial to long-life OLED display products. Lifetime is very important for large size applications.

Fourth, the current trend of the panel industry is to focus on large-scale lines, that is, the new investment production line basically starts with the 6th generation line, which makes it more conducive to the low-generation steaming process, and suffers from “upgrade” issues. The printing technology is precisely suitable for the use of high-generation lines.

Together, these reasons are enough to make printed OLEDs a trend of the day. However, the biggest bottleneck in the printing of OLEDs is the differential control between each tiny printing point, and the development of equipment for very small sub-pixel printing. The former is a key bottleneck for the entire printing and display industry, while the latter is mainly for small and medium-sized display products. - Or, for printing OLEDs, ink stability is not the ultimate

Big problems, equipment accuracy and stability are the real test. The latter, in fact, must be established after the establishment of an exemplary production line before it can be truly resolved from the project.

“Solving the Printing Accuracy and Process Stability Issues in Specific Engineering Practices, Scale, and Conditions”—This is the real bottleneck in OLED printing. This is also the biggest problem that Samsung, LG, Juhua Printing and other companies are trying to solve.

Is this a good solution? Certainly someone has to ask this. However, as a comparison, the problems encountered by transpiration technology in the manufacture of large-size OLED panels can also be summarized as "accuracy and process stability." In other words, after printing OLEDs and evaporating OLEDs, the core issue after large-size sizing is the same—who can win in the future depends on the technical route to solve this problem more easily.

In other words, the OLED printing technology in 2016, the essence can be understood as: steamed large size OLED is a bit difficult to imagine, so we choose to change another way - print OLED to try it. However, this is also a big impact on color TV. As for the OLEDization of mobile phones, there is no printing technology, which will not change the process of industrialization.

"Don't be happy too soon!" Because of this OLED thing, consumers are putting too many pigeons. Since 2012, Samsung has successfully postponed the arrival of LG's "OLED TV."

The reasons for this are not that vendors do not work hard, but because "too many choices" are distracting, and technical difficulties are greater. The combination of these factors has caused the "Samsung, LG" unceasing words.

From a technical point of view, Samsung's earliest line of love is "low-temperature polysilicon, steamed, RGB OLED." However, the fact is that the low-temperature polysilicon TFTs are difficult to be large-sized, and the size of the steaming process is not difficult to be large. RGB OLEDs are large in size, and it is almost impossible to achieve economical yields. Later, Samsung proposed the "laser thermal transfer" printing OLED, but it was not finally successful. To LG is smart, using a metal oxide TFT + half width steam + WOLED + color filter film route. This route bypassed several of the hardest cuts, such as RGB technology, and it was the first to introduce a large-scale production.

These technical analysis, we can see that the OLED roadmap is not easy: TFT on the glass substrate, the difference between the flexible substrate, low-temperature polysilicon and metal oxide two major technical routes; OLED coated with half a steamed, fully steamed , laser thermal transfer, inkjet printing at least four technologies; the final product selection also has WOLED + color filter film and RGB OLED two major differences.

Therefore, the conclusion is: There are too many possible choices, which leads to the possibility of taking the wrong direction. This is the key “opportunity risk” for OLEDs that have not yet arrived. If the entire industry and all of the power resources were initially focused on inkjet RGB OLEDs, perhaps the whole industrial process would be much faster.

The best news for the next generation of flat panel display in 2016 - manufacturers really believe that "inkjet printing" is the most critical process point, even for electroluminescent QLEDs. This technology is used by Samsung to "reverse OLED" technology. All must be based on the "inkjet printing" process. Once the OLED, QLED display industry, this unprecedented consensus on the "inkjet printing," then, OLED acceleration will be possible.

“Although the difficulties are relatively large”, “the industry has an unprecedented consensus” and a common development point, and over the years the industry’s efforts have made other key links such as OLED materials, OLED ink formulations, and TFT process materials “very mature”. This is the biggest good news for the OLED industry.

Here, the article basically ended, but the first question still needs to be added: Printing OLEDs come, how to do with existing OLED lines and under construction lines?

First of all, small and medium-sized wires do not need to be imported into the printing process. The steaming is now used very well. The built-up will continue to be used. Secondly, in the construction of the production line, the large-size wire is only line 9 of LG. This line will be in volume production by 2018, that is, his technology roadmap can be confirmed after the OLED is printed on the M2 line in 2017. Third, other small and medium-sized lines under construction can be scientifically adjusted with reference to the demonstration results of LG and Samsung. Fourth, the difficulty in reprinting OLED lines by evaporating OLED lines is not very big, mainly because of cost. Fifth, the large-scale OLED lines that have been mass-produced are only LG's M1 and M2. The scale of the two lines is not large. The cost of transforming into a printing line is acceptable.

Therefore, there is not much concern for the impact of new technology on the existing OLED line. Because before this OLED really did not go far, even if they come back and walk again, it is not a big problem. In addition, the proportion of evaporating components in OLED panel equipment is less than 30%.