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. When an electrical current is applied, light is emitted. OLEDs are used to make displays and lighting panels. OLEDs today are widely used in TVs, smartphones, tablets, laptops and wearables.
While OLED displays excel in color-contrast and efficiency compared to LCDs, they’ve also proven relatively hard to produce on a large scale. Current evaporation-based production techniques involve a lot of wasted material and risk of defects. OLEDs are also extremely sensitive to moisture and oxygen and therefore must be protected with a high performance encapsulating layer.
OLED ink-jet printing
Current OLED producing methods rely on evaporation processes, in which the organic materials are deposited onto a glass sheet through a thin metal stencil, also known as a "shadow mask. This process is problematic, as a significant amount of the material is wasted because it disperses all over the mask, in addition to inherent mask changes which expose the sheet to dust and compromise yields (OLEDs are by nature sensitive to contamination).
Inkjet OLED printing has the desirable ability to allow precision deposits without the use of a mask. It also produces less stray particles, thus boosting yields. These significant advantages make this technology interesting to many companies and virtually all OLED makers have active ink-jet printing development projects.
For many years, companies all over the world invested heavily in inkjet printing processes for OLED displays, but the process is not yet common, as printing OLED displays is a relatively challenging task, and soluble OLED materials are less effective than evaporable ones. Ink-Jet printing is also not able to reach the same high densities of evaporation OLED production, which limits its applications for large-area production (TV panels) and not small mobile, VR and wearable OLEDs.
Printed OLED panels on the market
One area in which inkjet printing is common in the OLED production process is the encapsulation layer deposition. Almost all OLEDs that adopt TFE encapsulation use inkjet printing to deposit the organic elements.
LG 32EP950 OLED monitor (31" 4K printed OLED panel by JOLED)
For actual OLED emitter layers deposition, currently the only company that commercially uses ink-jet printing is Japan's JOLED, who in 2021 started printing OLED display panels in its 5.5-Gen production line in Nomi, Ishikawa Prefecture, Japan.
The latest OLED ink jet news:
According to reports, Kateeva's QD-OLED printing project saga is not over. Samsung Display tested the company's latest printers, but these failed the tests and Samsung Display will not but these printers. SDC planned to replace the currently-used Semes' printers, which also suffer from low performance.
Samsung Display is also not committed yet to expand its QD-OLED production lines, which means that in any case it does not need to buy new printers for production expansion. Earlier reports suggested that SDC wanted to upgrade it current capability for higher density (to reach 8K TV printing), so this may be the reason behind the testing of Kateeva's new printers.
In 2021, we reported that two researchers working at Samsung Display were convicted of handing over OLED technology to other companies, and are being sent to prison for two years. Representative and directors of the company that bought the technology was also sent to prison and the company was fined. The technology in question relates to Optical Adhesive Materials used in OLED production processes. The arrest of these employees was reported earlier in 2020.
It is now reported that another employee of Samsung Display, also involved in that case (seems to be he was the main organizer of the outfit) fled Korea following his indictment, but has now returned voluntarily to Korea and has been arrested and is now bring charged with violating unfair competition laws in Korea.
Inkjet printing pioneer JOLED has filed for bankruptcy, following many years of struggles to increase production capacity and revenues. According to earlier reports from Japan, display maker Japan Display will take over JOLED technology and remaining operations.
There are now reports from Korea that suggest that TCL's CSoT is considering buying JOLED's OLED production equipment, and moving it to China to attempt OLED production in-house using inkjet printing. If this plan goes through, the plan is to initiate production in 2024. It's not clear whether CSoT is in talks with JDI, or whether JDI did not take over the equipment from JOLED.
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.
A few months ago we reported that Japan-based inkjet printing OLED developer JOLED has filed for bankruptcy, and that Japan Display (JDI) will take over JOLED's technology and operations. JDI released an official statement regarding JOLED and its plans for the future.
So indeed on March 7 2023, JDI signed a basic agreement to support JOLED. Since then the two companies held 'extensive discussions', following which JDI decided to form a subsidiary company called 'JDI Design and Development' or JDIDD, that will acquire JOLED’s OLED technology development business and all related operations.
TCL CSoT had several interesting new OLED demonstrations at SID DisplayWeek 2023, all of which were produced by inkjet printing, which shows the company's commitment to the new production process.
First up is the company latest inkjet-printed panel, this time CSoT showed a 8K (7680 × 4320) 65" TV panel that is foldable (with a bending radius of 25 mm). The panel offers a peak brightness of 800 nits, a response time of under 1 ms and a refresh rate of 120Hz.
Universal Display announced that it will detail advances in its latest PHOLED materials at Display Week 2023. The company's latest red, green, and blue PHOLED materials offer a narrow emission spectrum, which increases the efficiency of OLED devices, in addition to enhancing the color gamut.
UDC also unveil a new OVJP system printed on a 200mm x 500mm Corning Astra Glass substrate. UDC will also showcase the first-ever fully printed seven-layer (HIL/HTL/EBL/EML/HBL/ETL/EIL), 80 PPI, green commercial-level PHOLED device fabricated by its R&D OVJP system that has comparable device performance with vacuum thermal evaporation (VTE).
A report from Japan updates that JOLED , the OLED inkjet printing pioneer established in 2014, has filed for bankruptcy. The company has been struggling financially for a long time, and will now close down its two production lines and lay off 280 employees (out of 380), as it could not raise funds and has liabilities of around $257 million.
According to the report, display maker Japan Display will take over JOLED technology and remaining operations.
Inkjet printing developer Notion Systems is building a new company headquarters in Schwetzingen, Germany, with a new production plant. The company recently held a groundbreaking ceremony of the new building which will have 3,600 m² of floor space.
Notion Systems is growing at a rate of 20% per year, and these new premises are needed to cope with its increasing number of orders. The company estimates that 18% of its revenue in coming years will be generated from the display industry, for which the company offers machines for inkjet printing of OLEDs, QDs, and more.
Industrial inkjet printing developer Notion Systems announced that is has been selected by the Institute of Chemistry, Chinese Academy of Sciences (ICASS) for organic material R&D. Notion Systems worked together with its partner YixinTech as its system went through a long comparison against other inkjet printers in the market.
ICCAS is a multi-disciplinary research institute dedicated to basic research in broad fields of chemical sciences. One of its major research areas is organic materials for display applications.