OLED (Organic Light Emitting Diodes) is a flat light emitting technology, made by placing a series of organic thin films (usually carbon based) between two conductors - and these films light up when electrical current is applied. OLEDs are used to make display and lighting panels. OLED displays an offer excellent image quality, are thinner, more efficient than LCD displays, and they can be flexible.
One of the major problems with those organic materials is that they are very sensitive to oxygen and moisture. This means that OLEDs need to be protected - as even a single water or oxygen molecule can harm the OLEDs.
Thin Film Encapsulation (TFE)
With regular (rigid) OLED panels, one can use a glass sheet. Glass is a great barrier, and it is widely used in the display industry and so easy to handle.
For flexible panel, rigid glass is not a a good option, and in such panels producers use different techniques, collectively referred to as Thin Film Encapsulation, or TFE. TFE is a multi-layer film, made from alternating organic and inorganic layers.
Most organic layer TFEs use an inkjet printing process. Inkjet printing is used to deposit the organic TFE materials. Kateeva launched an encapsulation inkjet printer system towards the end of 2014, and in 2016 the company announced that it secured the "vast majority" of available TFE orders.
The inorganic TFE material deposition can be done in different methods. The incumbent technology for the inorganic TFE deposition is Plasma-enhanced chemical vapor deposition (PECVD) while Atomic Layer Deposition (ALD), a modification of the basic CVD process, seems to be gaining ground in the TFE market as it enables thinner and more uniform films.
The latest OLED encapsulation news:
LG Display detailed its latest automotive display strategy. The company is now offering three product family. For luxury flagship cars (over $80,000 in cost), the company is offering its P-OLED flexible panels, that offer high performance coupled with design freedom.
For premium cars ($50,000 - $80,000) the company offers rigid OLEDs, that offer high image quality and a tandem OLED architecture for increased efficiency and lifetime. These displays are lower in cost compared to LG's P-OLEDs, and LG brands these as ATO (Advanced Thin OLEDs) as they adopt TFE encapsulation over a glass substrate. For mass market cars ($30,000 - $50,000) LGD offers LTPS LCDs.
According to a report from Korea, Apple approached both LG Display and Samsung Display, asking its suppliers to develop a completely bezel-less AMOLED display for future iPhones.
Designing an OLED without a bezel is a challenge, mostly because of the encapsulation layer that has to protect the OLEDs. Using an under-the-display camera is also said to be a problem for the OLED makers in such a design.
According to reports from Korea, Samsung Display is interested in acquiring OLED IP and patents from Semiconductor Energy Laboratory (SEL). These patents detail an OLED production process that does not require the use of fine metal mask (FMM) evaporation.
The use of FMM to deposit and pattern OLED displays is seen as a major setback towards higher density OLED displays, and it also limits the aperture ratio. It is no wonder that Samsung is interested in such technology, as other display makers have developed similar technologies that offer massive performance boost over the standard FMM process.
Notion Systems, a leader in ink jet printing for industrial applications, has been active in the display market for a long time. The company is now promoting its EHD technology for high precision printing. Here’s an interview we conducted with Antonio Schmidt – SVP Sales & Business Development and Jochen Seeser – Senior Process Development Manager, Notion Systems.
Hello Antonio and Jochen, thank you for your time. In 2022, you started offering EHD printing systems. Can you explain how this technology works and what applications does it enable in the display industry?
Notion Systems has been active in the display market since 2016, when we delivered an n.jet display for pixel printing to a lab of a leading display manufacturer in China. Since then, we have supplied several inkjet displays for RGB printing and encapsulation to various R&D and production sites in China and Taiwan. I think we can also claim that we are the only manufacturer, along with perhaps one other U.S. competitor, that has multiple systems in operation for 24x7 display production.
This is a sponsored post by Ergis Group
In 2020, Poland-based Ergis Group launched the noDiffusion film platform, a high-barrier film that offers high level of optical transmittance and low level of light scattering, and the ability to contain transparent conductive electrodes. The new technologies adopted in the production of the barrier films offer a combination of high performance and competitive pricing.
Ergis has been busy since 2020, scaling up its production capabilities, and progressing towards production in a roll-to-roll configuration (rather than the batch system it used before). Ergis is using two different technologies - ALD and sputtering to deposit the barrier and the conductive electrodes.
Merck introduces new OLED encapsulation materials that the company says offer superior flexibility, higher reliability, and longer lifetime for flexible devices compared to existing solutions.
Merck says that its new low-temperature ALD silicon materials offer highly improved barrier characteristics - 100 times more effective than current solutions. And they can be deposited in thin layers - 20 times thinner than existing solutions. Merck introduced low-temperature ALD silicon materials in 2022 for automotive OLED, and the company expects that the new materials will be used for the encapsulation of flexible IT OLED displays (laptops, tablets and monitors).
Apple's interest in OLED displays for future iPad tablet device is not secret, and many analysts estimate that the first such device will be released in 2024.
One of Apple's requirement is for superior performance for its tablets compared to smartphone AMOLED displays - and so developers are relying on a tandem OLED structure. According to a new report from Korea, LG Display is developing another unique technology for Apple's iPads.
The Korean Supreme court put an end to a years-long legal battle between LG Display and Samsung Display, saying that SDC's employees and a chief executive of one of LG's suppliers are not guilty in IP theft.
The supreme court upheld the original ruling and dismissed the appeal. The case revolved around LGD's face seal encapsulation technology for OLED displays. The main issue in the legal case was whether leaked LGD documents were trade secrets. The employees and executives were first found guilty, but at a higher court they were found innocent as it was decided that the information was already widely known in the industry.
According to reports in Korean media, Samsung is developing a new process which will allow it to reduce the thickness of its QD-OLED panels.
The current QD-OLED design uses two glass substrates, one for the TFT backplen (and the OLED frontplane materials), and one for the QD conversion layer. The new plan is to remove the QD glass substrate, and inkjet print the QDs directly on the OLED TFE encapsulation layer.
Poland is aiming to become a major innovation and high-tech hub, and the country is already enjoying a growing industry, focusing on IT, bio-technology, robotics and nanotechnology.
Poland has a strong material science and development expertise, and in recent years we have been seeing OLED and display-related ventures out of Poland. It seems Poland is poised to become an interesting location to watch for future innovation in the OLED industry.
Ergis Group noDiffusion OLED encapsulation film
One such company is the Poland-based Ergis Group, a leader in plastic processing active in markets such as food packaging, industrial, automotive, medical and more. In 2020, Ergis launched its first product for the optoelectronic applications (such as the display market and photovoltaics) - the Ergis noDiffusion films for flexible OLED panels (both displays and lighting) and OPVs. Ergis is using a unique ALD-based technology that enables it to offer high performance films on low cost PET films.