"Currently, flexible OLED displays require polyimide films, because they require very high transparency and high refractive index." Professor Harris, chairman of the American APS company, at the "2017 China International Forum on Flexible Display Technology (Materials)" In an interview with New Materials Online®, APS said that it hopes to open more markets in China, and this cooperation with Xinlun Technology also hopes to introduce high-tech technology into China as much as possible.
The previous announcement of Xinlun Technology on December 11 stated that the company and Akron intend to establish a joint venture company Polyurethane Material Technology (Shenzhen) Co., Ltd. According to reports, Akron will invest in "negative birefringent polyaryletherimide film technology for liquid crystal displays."
At the same time, Xinlun Technology also announced that in order to further enhance the company's R & D and innovation capabilities in the optoelectronic display industry chain and to lay out the next-generation flexible display material market through resource integration, the company's wholly-owned subsidiary Hongkong Xinlun intends to acquire Akron 45 % Equity, the purchase price is $ 9.9 million.
According to Professor Harris, Polylon will be a functional platform company for the research and development and incubation of polymer materials industry technology to achieve the three goals of "resource integration", "intelligence" and "education". Technology research and development cooperation platform and carrier, and through the company and universities to jointly build joint laboratories for technical cooperation, independent development, third-party development or other forms of technology research and development activities agreed by the two parties to obtain high-tech results, and Promote and realize the industrialization and marketization of scientific and technological achievements.
"I think the polyimide film will be sold very well, because this technology has been applied very well." Professor Harris emphasized that, in particular, S-Plate will be very expensive, its lighting effect is very good, and it is good for light. The requirements are not so high, and the size of its film will be very thin.
According to reports, APS is located in Akron, Ohio, USA. The local University of Akron has a polymer science school and polymer engineering. There are already more than 360 companies focusing on polymers in Summit County, Ohio. APS currently provides products including flat panel displays, optical films, LCDs, optical interconnect half-pads, as well as high compression fiber and high film volume.
Professor Harris has also worked at the University of Akron. He has studied in the field of polymer polycondensation for more than 30 years and enjoys international reputation. He has obtained more than 30 patents and 200 major scientific research results.
Flexible OLED displays have the advantages of being flexible, thin and light, fast response, wide use temperature range, and their applications are becoming more and more widely. They have entered an explosive growth stage in small-sized markets such as smart watches and smart phones, and large-sized displays such as television In the field, the application of flexible OLEDs is also steadily increasing.
The key to flexible display is to use a polyimide substrate instead of a glass substrate that is not easy to bend, and it must have excellent heat resistance and dimensional stability.
"Akron has great advantages in this aspect. Research on polyimide films has been for more than 20 years." Professor Harris told New Materials Online® that Akron can design the structure of polymer molecules and design flexibility. OLED and specifications that meet the basic needs of OLED lighting, while our approach is to provide materials for the flexible display market.
The following is a short note by Professor Harris on the "2017 China International Forum on Flexible Display Technology (Materials)", New Materials Online® collation.
Polyimide film and its application in flexible displays
Today I will highlight the research results that I have spent more than 20 years. I have several pages of content that will focus on the application of polyimide films and flexible displays. My lecture will have such several parts. In the first part, I will introduce the APS system. I will tell you how we started and how our system was produced, and then how do we promote this system to market. You can see that we have been engaged in this area for many years. The second part will talk about a soluble, that is, our market. We mainly want to search for soluble polyimide materials and put them into the use of flexible displays. I will also talk about birefringence optics and LED colorless substrates.
APS History
First, a brief introduction to our company. Our company is in Akron, Ohio. There are a lot of companies in this city focusing on polymer chemicals. We have a long history here. At the same time, you can also see the University of Akron, as well as the College of Polymer Science and Polymer Engineering. This is a very old project in the United States. At the same time, its scale is very large. This project is also very old. As you can see in the United States, there are already more than 360 companies focused on polymers in Summit County, Ohio.
From 2005 to 2017, we have developed very well. We have already applied many devices to various institutions in the United States. The picture on the left is our experimental picture. At the same time, we have some experimental places to apply these. Polymer materials, such a pilot has more than 60 field sites, so you can see that our investment and research are very large, and our knowledge of this area is also very professional. In the past few years, we have had more than 300 research projects. Professor Cheng Zhengdi will involve this very core technology, that is, the technology of optical compensation, that is, the display. Optical plays a very important part in the display, because the quality of the display is related to the projection and reflection of light. Great relationship, so all it has to do in this part is to compensate all the optical parts into the display. At the same time, we can see that we have launched a lot of layouts, such as X-plate, APS-C2, S-Plate, etc. In particular, such an extensible and flexible interface has been applied to many smart phones. Our work will focus more on the use of highly analytical materials. Today I mainly talk about the application of polymer materials. These polymers will be of great help to all displays. I think polyimide films will surely sell very well because this technology has been used very well. In particular, the S-Plate I just mentioned will be very expensive, its lighting effect is very good, the requirements for light are not so high, and the size of its film will be very thin. If you want to touch such a film, you can touch it in your pocket. This is a very advanced technology, so it will be very expensive.
Let's take a quick look at some of our main work. You can see that our work is mainly focused on these aspects: flat panel displays, optical films, LCDs, optical interconnect half-pads, and we will also engage in high pressure resistance. fiber.
In addition, we have also made some films with a high film volume, about 15GPa, which is a relatively high value. This is also the case for DuPont films. We have a better idea to make some high-membrane films, in addition to some high-temperature composite resins, like some carbon fiber reinforced ingredients, some molecular compounds, and some nylons, we will eventually produce more Good molecular complex. In addition, we have also made some optical and optical cross-linking systems, which is also a very important part of our work.
Flexible application of polyimide film
After long-term research, we found that the polyimide of the rigid rod can be soluble in some organic solvents after chemical treatment, and its decomposition temperature is also very high. The temperature we see here is 585 degrees Celsius. A decomposition is carried out here, there are some systems that can be blocked, and then a better stability can be achieved. A test was performed at 585 degrees Celsius, and finally we achieved a relatively good stability. Now we have rediscovered this new type of combination, which can be processed with polyimide, and finally obtain a soluble polymer, which is even soluble in the same solvent. After generating these films, we studied the characteristics of these different films, such as what the in-plane orientation of these materials was tiled, and whether there were some deformities and shrinkage. This is very important. When we stretch the polymer film, we will see the phenomenon of alignment in this plane. This phenomenon is actually a solution we have found during continuous exploration. Its in-plane and out-of-plane reflection indices are different. There is also a negative birefringence here. If you stretch the film, there is an in-plane birefringence.
I also mentioned that their transmittance is relatively high, and the 350 nm level has a better transmittance.
We studied the characteristics of optics and did many experiments to compare the effects of 6FDA and PFMB on stiffness. 6FDA has a second twist here. After the second twist, we increase the stiffness and the CTE becomes very low. It becomes 18PPM / degree Celsius. Now there is a better UMB and it is more stable. In general, its characteristics are better, and the final polymer performance is better. Here we show you that there is a group here. This group will affect the density of the assembly. If you have a small group, you can see that all our steps slowly rise and change from large to small. As they get closer, there will be more CTEs or lower CTEs.
We use VA-mode LED negative film compensation film. This method can affect the main parameters of UNB and CTE. With the linear increase in steelmaking, you will see a situation where the UNB increases and the CTE decreases. We will also study in two ways. As the packing density decreases, we will also have such a negative film compensation film. At the same time you can see that the UNB here will also decrease, while the CTE will increase.
The material used for the basic polyimide resin of flexible LCDs has been described a lot, its performance is also very obvious, and its transparency will be very high, especially when the contrast of 427 degrees and 440 degrees is reached, their transparency is still It can exceed 85%, and such a size is accurate to the range of 400 nanometers. You can also see that the CTE is between 62-65.
This performance is about the basic performance of all flexible OLED substrate resins. It can be seen that the performance here is very good, its bending ability will become stronger than before, and the tensile strength will also be very strong. It is also soluble in water, which is a common organic solvent. You can see that this is also a chemically resistant substance. After 30 minutes, it will show such a super performance, that is, our chemical resistance, when it exceeds 300 degrees Celsius. It can be seen that this is the process of our film production. We cast the APS-2004 roll-to-roll film. We produce a substrate that is about 30 cm wide and 50 microns thick.
Let me talk about the flexible OLED polyimide material that has not been finished just now. To use such a substance, that is to say, the extraction of flexible OLED lighting requires the following requirements. It requires very high transparency, at the same time its index of high refractive index is very high, and its Tgs is also very high. There are other characteristics, such as its very high thermal stability, and it is also very easy to handle. Such a method is already in the prototype for OLED lamps.
We hope to let you know through such a demonstration that the success of our company's work in this area, we hope to open more markets in China, so that more companies can participate in this project, and at the same time we hope that we can The introduction of such a high-tech technology into China can do even greater promotion.