Proud to be the world’s first, Transparent OLED Development Team of LG Display
LG’s transparent OLED display is always described with the modifier “the world’s first” or “the world’s only.” We have met those who are at the forefront of transparent OLED display development and always working to improve the technologies and designs: Professional Kim Bin, Professional Park Sung-hee and Specialist Ko Tae-hee of OLED Panel Research Team 3 under LG Display CTO.
(From left) Professional Park Sung-hee, Professional Kim Bin, Specialist Ko Tae-hee of LG Display
Professional Kim proposed the transparent OLED display project and led the development from the initial stages. He now oversees the project. Professional Park has also been part of the transparent OLED development starting in the 2012 national project. He went away for a while to get his degree but came back in 2019. Now he mostly focuses on panel designing work. The first project Specialist Ko took on after joining LG was transparent OLED display. His current job is to evaluate and analyze technological application on panels.
Birth of display the world has never seen
LG Display developed and showcased 77-inch transparent flexible display for the first time in the world
in 2017 national project performance sharing event.
Image source: LG Display blog Dsquare
Development of transparent OLED display dates back to 2012. LG Display had been selected as the sole developer of transparent flexible display as part of a national project named Future Industry Leading Technology Development Project. In 2017 which was within five years after initiating the research and development, LG Display surprised the world by succeeding in developing 77-inch 80R (a curvature radius of 80R means that the screen functions properly when the panel is rolled into a circle with a radius of 8cm) UHD transparent flexible OLED display. Not only did it meet the specifications target but exceeded it. After the success in the national project, the company in 2019 started mass-production of 55-inch transparent OLED display with a transparency of 40%.
Q. Could you introduce what the transparent OLED display technology is?
Professional Kim Bin: Transparent OLED display is a panel that shows images and the background of display to the viewer at the same time. Its most unique feature is the “sense of openness” that comes from the backside made visible. The keys to this technology are transparency and the large-area top emission structure.
To be able to build a truly transparent display, it is imperative to secure high transparency. When we started research in transparent display, we did a survey of company employees, and the result was that people started to recognize something as transparent when the transparency is 30%. The transparent OLED display currently being mass-produced has a transparency of 40%.
Also, the transparent OLED display uses the top emission method where light comes out through the transparent electrode and then the front side. Since this method uses a larger area for emission and penetration, it makes it possible to improve both durability and transparency of the display. If you use transparent electrode, resistance goes up. For this reason, it had been difficult to apply it to large-area display. But LG Display overcame this and developed this structure that allows us to use transparent electrode for large-area display for the first time in the world.
Professional Kim Bin of LG Display
Q. What are the reasons why transparent OLED display is coming to the fore as the next-generation display?
Kim Bin: Large and dark-colored displays are called “black monster” because they often disrupt the space and feel out of place. As a display gets bigger, such sense of foreignness can only increase.
However, transparent OLED display does not feel disconnected from its surroundings. It is safe to say that you can use a transparent OLED display wherever there is a glass window. Right now, it is mainly being used in public facilities, public transportation means such as subway and premium stores, but we expect that in future it will be used for delivery of information not only as a household TV but in wider variety of areas including architecture, vehicles and airplanes.
Transparent OLED display displayed in Magok showroom of LG Display
Researching the world’s first with unrivaled technology
Right now, LG Display is the only company in the world that is capable of mass-producing transparent OLED display. Our competitors have introduced their own transparent OLED products, but they were all prototypes and could not be further developed for mass production.
However, based on its unmatched technology, LG Display filed as many as 147 patents related to transparent OLED display. That accounts for more than half (52.5%) of all patents on transparent display in Korea. Our success in the national project for transparent flexible OLED display and the subsequent mass production further led us to signing a contract for a national project for stretchable display.
Professional Park Sung-hee of LG Display
Q. What was the biggest difficulty that you faced during the entire research process? How did you overcome it?
Kim Bin: Since collaboration between experts from various fields was absolutely necessary, we could not integrate everything into a whole without understanding of one another's fields. It was not easy to understand the entire processes related to development of transparent OLED, but there were cases where the solution for a problem that occurred in one area was found in another area.
The research process was a painstaking one, but thanks to our experience in conducting a national project, we were able to quickly build mass production infrastructure for transparent OLED in the plant. So, we could resolve the issues in mass-producing large-area panel fairly quickly.
Professional Park Sung-hee: It was difficult to discover new materials through new methods and to have to develop everything anew. Also, for top emission, the panel's front side must be transparent. The technology itself for creating transparent electrode instead of metal one requires a highly sophisticated process. With all these related factors, implementing the technology was not an easy thing to do.
Specialist Ko Tae-hee: While it was important to make the panel transparent, it was also important how the screen turned out. Since it was our first time in everything, there were not even proper standards in place for technical evaluation. So, we had to build one ourselves. Since our research involves new technologies almost every time, we continue to work with other teams to find the right technical methods.
Q. What are the technological outcomes of transparent OLED display and its impact on the market?
Kim Bin: The biggest feat we achieved was the fact that we have created a new category of displays. In fact, transparent displays using LCD existed in the past. However, LCD has a very low transparency of around 10% and poses the spatial limitation that the surrounding must be bright. In contrast, transparent OLED display has a very high transparency of over 40% and emits light by itself, so it can be installed anywhere. So, we have created an entirely new category of displays with this display that fully harmonizes with the surrounding.
Another feat was that we acquired the large-area top emission structure technology. If you only consider mass-producibility and some other factors, the bottom emission structure currently being used in OLED TV is quite suitable. But as display’s range of application is getting more diverse, including even extreme environments, the top emission structure with its improved durability will become more useful.
Specialist Ko Tae-hee of LG Display
Q. With regards to customer values, what is the ultimate goal of your research and development on transparent OLED display and what challenges do you need to overcome to achieve this?
Kim Bin: To commercialize a technology, it is important to lower the cost and raise accessibility as well as to improve performance. Right now, we are focusing our research on improving the performance and design of transparent OLED display, but we expect there will be research for increasing cost efficiency as well. In addition, we are making efforts to eliminate limitations as to its applicability in different fields. Our goal is to develop various forms of transparent OLED display to cater to the various needs of consumers.
Park Sung-hee: While it is important to lower the cost and improve accessibility, it is also important to enhance the added values through design and branding considering the fact that transparent OLED display itself is a premium technology. We need collaboration between various fields for this, and in this aspect, LG Sciencepark definitely provides an advantage since there are many subsidiaries working together in this place. As a researcher of displays, I look forward to seeing display development function as a hub where LG’s different technologies are gathered into one.
Ko Tae-hee: I think we should stop seeing displays as simply a component of TV or signage. If we can make them compatible with other electronics or integrate them with communication technologies, we will surely be able to increase the value in terms of technology and brand.
I feel proud to be part of LG Sciencepark.
When Professionals Kim Bin and Park Sung-hee moved together with their research teams from Paju R&D Center of LG Display to LG Sciencepark, they expected to see synergy effects between research teams from different subsidiaries. Specialist Ko Tae-hee, who has worked in other business sites through job rotation before, points out the outstanding accessibility and fresh research environment as the best things about LG Sciencepark.
Professional Park Sung-hee had contributed with ideas to establishment of LG Sciencepark as part of activities of the junior employee board FB (Fresh Board). For her, it brings up memories to see the completed LG Sciencepark which she had only dreamed about.
Q. What are the best things while working in LG Sciencepark?
Kim Bin: It is inevitable to be influenced by your surroundings, and if there are production facilities along with research facilities, I get to do a lot of research related to mass-produced products. This is not necessarily a bad thing, but thinking about mass-producibility first can lead me to place limits on research or fall into fixed patterns.
Here in Magok LG Sciencepark, we can think more openly. Since research teams from different subsidiaries are together in one place, collaboration is easier. Also, there is a plenty of parks and resting places, so whenever time allows, I walk around because it helps me to come up with new ideas.
Park Sung-hee: While in Paju, I considered myself as a researcher for the company LG Display. But after coming here and seeing the research facilities of other subsidiaries and meeting many different people, this view of myself changed and I started to see me as a researcher for LG. That’s when I started to think that I should work for development of LG’s technologies, rather than just focus on displays, through mutual cooperation. I think that was a big change as a researcher.
Ko Tae-hee: Most of all, I like the fact that LG Sciencepark is in Seoul. The ease of commute is a huge advantage. Also, when you get tired working, just looking at the beautiful landscape of the LG Sciencepark or the nearby botanic park really helps. Luckily the research building which I am in faces towards the botanic park, and looking at the panoramic view of the botanic park from the third floor helps me get new ideas.
Q. How would you describe LG Sciencepark in one word or sentence?
Kim Bin: “The heart of LG R&D.” It might sound like a cliche, but I wanted to highlight that it is the hub of technologies that brightens the future of LG.
Park Sung-hee: I have always loved plants. So, I want to describe LG Sciencepark as “the place where you plant and grow trees of LG's future.” Although we are now in the stage of planting trees, we will be able to see a completed LG ecosystem that is as rich as the Amazon forest.
Ko Tae-hee: I would describe it as “a place where freedom abounds.” Companies can be a strict and boring place, but in LG Sciencepark freedom of its members is respected, so it’s the best place where you can concentrate on your research.
Q. Please share with us your future goals and plans while working in LG Sciencepark.
Kim Bin: R&D researchers feel it most rewarding when they see the actual final product that embodies the technology they developed being mass-produced. Thankfully, while working in LG Display for more than 20 years, I have had the chance to work in D-IC reduction technology (GIP, etc.) and in transparent OLED display for 10 years each and see both of these technologies being applied to actual products. My goal is still to see that the technologies that I help to develop lead to mass production and result in products that satisfy the consumers.
Park Sung-hee: I always have the mindset that the research I am doing is the best in the world. When I did not have as much work experience, I couldn’t even begin to associate my work with such pride, but now that I look back on the past, I have been part of really significant times in the history of displays.
Because this is what I do everyday, sometimes I forget how much our research matters and how much more convenient it can make customers’ lives, but from the perspective of outsiders, what we are doing is research in the world’s first and most advanced technologies. I want to continue to see my research result in mass production, so I can proudly tell my children “Dad worked on developing this technology.”
Ko Tae-hee: I have never been part of technology development yet, but in this aspect, I am learning a lot and gaining much positive influence from Specialist. As a researcher, my primary goal is to apply the technologies I develop to actual products. I don’t wish to develop technology for the sake of advancement itself, but rather I want to make what the customers truly want. As for the transparent OLED display technology that I am currently working on, I want to develop it into something more familiar to customers, something everyone wants to use.
