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:
According to reports from Korea, Unijet has supplied China-based Sidtek with inkjet printing systems, used for thin-film encapsulation (TFE) deposition of OLED microdisplays. This is Unijet's first sell of a commercial TFE printing system.
Sidtek, established in 2016, is now producing 0.39" XGA OLED microdisplays, which are available on the OLED marketplace. Sidtek's 0.39" display is available in a color version (1,000 nits) or a monochrome one.
Panasonic announced a new thermoset stretchable film for printed electronics, called Beyolex. Panasonic targets several applications for its new film, including OLED substrates and encapsulation film.
Beyolex is based on a proprietary non-silicone thermoset polymer chemistry developed by Panasonic researchers at the company's Electronic Materials laboratory in Osaka, Japan. The film features softness, conformability, high temperature resistance, and ultra-low permanent deformation after stretching.
An AILU (Association of Industrial Laser Users) webinar, scheduled for September 15, will introduce the basics of OLED lighting, discuss the choice for the right substrate and encapsulation material as well as the current status of roll-to-roll processing. The webinar is sponsored by 3D Micromac, the industry leader in laser micromachining and roll-to-roll laser systems.
The webinar will also show results from the EU-funded LAOLA project, which is a collaboration between German and Japanese companies and research institutes. The LAOLA project, led by the Fraunhofer FEP, develops the use of ultra-thin flexible glass as a substrate and encapsulation material in roll-to-roll technology for this purpose.
Last year, Poland-based Ergis Group launched an OLED encapsulation film platform called Ergis noDiffusion®. The company is currently testing its film solutions at customer sites in Asia, the EU and the US, and it is now starting to expand the platform for the protection of quantum dot films (QD films) used in display and lighting applications.
These new films can be tuned to fit specific needs. Ergis can deploy its films on several substrate types, with varying film thickness, and the barrier properties can be tuned to be between 10-6 to 10-3. This means that custom films can be created to suit the specific sensitivity of the QDs for water vapor and to achieve specific product lifetime or other required properties.
Last month we posted that the Korean Elec publication claims that Apple is aiming to adopt OLEDs in its next iPad Pro devices - and as Apple wants extended lifetime from these panels, the Korean panel makers are developing tandem OLED devices (easier for LG as it is already producing such panels for automotive applications).
Today another Korean publication, ETNews, has posted that Apple is aiming to start using OLEDs in its iPads in 2022. According to ETNews, Apple indeed reached out to both LG Display and Samsung Display for these OLEDs.
Poland-based Ergis Group has developed a new solution for OLED panel encapsulation. The noDiffusion film, developed in collaboration with Ergis' partners can be adopted as both the flexible substrate and the encapsulation layer for OLED devices.
The Ergis noDiffusion film offers high barrier properties, high level of optical transmittance and a low level of light scattering. This enables the production of OLED displays with extended lifetimes, efficiency and image properties. The noDiffusion film can also be used in the production of solar panels to increase panel efficiency and lifetimes.
Ergis says that the biggest advantage of its new film solution is the lower manufacturing costs, as the films already include an embedded encapsulation layer and could optionally include an embedded electrode layer.
Omdia says that the global foldable OLED display market will grow from 700,000 units to 3.9 million in 2020 (a 5X increase) - and will continue its fast growth to reach 73.1 million in 2025.
Omdia says that the main challenge of the foldable OLED market is the reliability of the displays - mainly the cover, the touch sensor and the polarizer films. Display makers will need to adopt new technologies such as ultrathin glass covers (UTG), touch sensors on TFE and color filters on TFE
Meyer Burger announced that it is selling its PixDro inkjet printing business to Germany-based Suss MicroTec SE. The agreed price is $5 million, and the transaction is expected to be completed by the end of February 2020. Meyer Burger reveals that PixDro currently has annual sales of around $8 million. This transaction continues Meyer burger's strategic focus on its solar (PV) business.
PixDro develops and manufactures inkjet printing equipment for for the electronics and semiconductor industries. PixDro started out as a startup in Isarel, and was later integrated into the Netherlands-based OTB-Group, which was later renamed Roth & Rau AG, which was then acquired by Meyer Burger. The company continues its journey and will now be part of Suss MicroTec.
According to a report from Korea, LG Display has halted production at one of its production lines at its E6 production fab, LG's 6-Gen flexible OLED line that commenced production at the end of 2018.
According to the report, the problem lies with LGD's thin film encapsulation equipment - specifically the equipment that deposited the organic particles - which apparently suffers from sub par performance, not good enough for commercial production. LG is using equipment made by its subsidiary LG PRI in the E6-1 line, which is now halted.
Researchers from the Korea Advanced Institute of Science and Technology (KAIST) developed a self-powered wearable and washable OLED display device. The whole device is fabricated on textiles and the efficient OLED devices are driven by polymer solar modules.
Both the OLED device and the polymer solar panels are sensitive to moisture and oxygen, and regular OLED encapsulation will not protect such a device when washed. The researches designed a new washable encapsulation barrier using both ALD and spin coating. The device is flexible (curvature radius of 3 mm) and survived 20 washing cycles of 10 minutes each with little change in performance.