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 can be used to make displays and lighting, with possible applications that span TV sets, computer screens, mobile phones, decorative lighting and more. Since OLEDs emit light they do not require a backlight and so they are thinner than LCD displays, and are also more efficient, simpler to make and boast a better color contrast.

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. All of these issues hinder OLEDs’ market takeover, but much work is put into resolving them.

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.

Inkjet methods form films by discharging the required amount of organic material onto large glass substrates in regular atmospheric conditions. This could be done, for example, by placing OLED pixels on glass or plastic using a portable platform and nozzles. Such methods have the potential to increase yields and lower prices, thus enabling OLED technology to take its deserving place in the market.



Unfortunately, OLED inkjet printing is not yet common, as printing OLED displays is a relatively challenging task for many reasons. A number of layers need to be deposited in pixels (the size of the pixels themselves is defined by the overall resolution the display will have). Being able to place the right number of drops of the active materials into the pixels is a challenge, in addition to developing a process in which the ink dries to deliver flat films of materials in the pixel.

Despite major progress, it is maintained that soluble OLED materials (required for inkjet printing) 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.

Ink Jet printing is still not used in any commercial OLED display production. But progress in past years have been rapid and some believe that initial OLED TV production using ink jet printing may begin in 1-2 years.

Latest OLED ink jet printing news

UDC accelerates its OVJP R&D, shows how the process works

Jul 07, 2017

Universal Display recently announced that it is accelerating OVJP R&D, and the company is looking to commercialize this technology with partners. UDC expects it to take a few years before OVJP can really be deployed in production. The company published the video below that shows off the technology and explains the basic principles and advantages.

OVJP stands for Organic Vapor Jet Printing, and the basic idea is to use a gas-stream based process that resembles ink-jet printing but one that uses evaporation OLED materials which outperform soluble ones. In an OVJP process, the OLED materials are evaporated into a carrier gas that delivers them to a jet engine for direct printing of patterned OLED layers. OVJP is intended for large-area OLED displays and can be scaled up to 10-Gen substrates according to UDC.

Sumitomo Chemical starts to promote P-OLED materials and printers for OLED display production

Jul 06, 2017

Sumitomo Chemical acquired CDT back in 2007, and since then the Japanese company has been developing it's P-OLED (polymer-based OLED) materials and technologies. While initially Sumitomo aimed to produce materials for displays, in recent years it has focused mostly on OLED lighting materials and even panel production.

Touch panel production fab, Sumitomo

A noted exception was Panasonic's OLED TV development project which used printing technologies and Sumitomo's P-OLED materials. But Panasonic terminated this project in 2013. We speculated that JOLED, which is based on Panasonic's technology (and other technologies as well), uses P-OLED materials in its prototypes, but we were not sure.

OLED Handbook

LG aims to adopt a blue TADF emitter in its 2018 OLED TV stack

Jul 06, 2017

Korean news site DDaily posted an interesting article that states that LG Display is looking to replace the fluorescent OLED emitter used in its OLED TVs with a blue TADF emitter.

LG OLEDC7 photo

Following the introduction into LG's OLED TV production process, LG hopes to also use TADF materials in its small and medium OLED production. The report is a bit confusing, but it seems that LGD also aims to use its WOLED display in small and medium display formats - even for VR applications.

Sony may be JOLED's first customer for its 21.6" 4K medical OLED monitors

Jun 08, 2017

Last month JOLED announced that it started to sample 21.6" 4K OLED monitors. JOLED plans to develop these OLED monitors for medical applications - it will produce these in low volume at its current 4.5-Gen pilot production line, and will start mass production in 2019.

JOLED 21.6'' 4K oled medical monitor prototypes photo

JOLED's CEO, Nobuhiro Higashiiriki, said in a conference that these first samples were shipped to Sony, which may become JOLED's first customer. JOLED says that the company managed to achieve a high quality and long lifetime, which was a challenge due to the printing process used.

BOE to use Kateeva's inkjet printed to establish a pilot OLED TV production line in Hefei

Jun 08, 2017

In February 2017 BOE Display announced that will establish a new R&D OLED TV production line in Hefei. According to Digitimes, BOE Display is intending to use an inkjet printing process in this line, and the company already placed an order for an inkjet deposition system from Kateeva last month. BOE will use the systems to produce 55" OLED TVs.

BOE 55'' UHD panel prototypes (Nov 2016)

In February BOE announced that the new line will cost 1 billion CNY (around $145 million USD). BOE will invest 80% of the funds, with the rest provided by the Hefei government. Digitimes now states that the new line will only cost 600 million CNY - so it may be that the inkjet printing line is an addition to the 1 billion CNY line (which in that case, will probably be based on an evaporation process).

BOE demonstrates Q-LED display prototypes

May 30, 2017

Last week BOE demonstrated two Q-LED displays, 5" (320x240) and 14" (960x540). These prototype displays use electroluminesence quantum-dots as emitting materials.

BOE Q-LED display prototypes at SID 2017

According to BOE, switching to an in-organic emitter enables a display that features an excellent display quality - on part with OLED displays - while also being compatible with ink-jet printing, which will enable QLED displays to be lower-cost compared to OLEDs.

IHS: OLED TV shipments to reach 10 million 2023, but growth will decelerate

May 19, 2017

IHS says that OLED TV shipments will reach 10 million units in 2023, up from about 1.5 million in 2017. The OLED TV market will grow at a CAGR of 42% from 2017, but the growth will decelerate as can be seen in the chart below.

AMOLED TV shipments forecast (2015-2023, IHS)

The high costs of producing OLED TV panels will remain a challenge and will be the main reason why production of OLED TV panels won't accelerate in the near future. Producers are looking into ink-jet printing as a way to lower production costs but the soluble emitting materials are still under performing and also the production yields are still low. IHS says that OLED makers are aiming to start mass printing OLED TV panels by 2019.

JOLED starts to sample 21.6" 4K printed OLED monitors

May 19, 2017

JOLED announced that it started to sample 21.6" 4K OLED monitors. These monitors, demonstrated in March 2017, feature a 3840x2160 resolution (204 PPI), a brightness of 350 cd/m2 and a contrast ratio of 1,000,000 : 1. The panel thickness is 1.3 mm and the weigh is 500 grams.

JOLED aims to start mass producing these panels in 2019, but will also attempt to sell these to the medical market even in low-volume production out of its current 4.5-Gen pilot production line.

Merck - printed red, green and blue OLED efficiencies are now comparable to vapor-processed ones

Apr 21, 2017

Merck is going to discuss its latest soluble OLED material performance at SID DisplayWeek 2017 next month. Merck will detail the printed device efficiencies, voltages, and colors.

According to Merck, the efficiencies of its soluble OLED emitters are now comparable to state-of-the-art vapor-processed devices. Merck will also suggest a move from an evaporated blue common layer device architecture to a printed blue.

Cynora's CMO: we're on track to commercialize blue TADF emitters by the end of 2017

Apr 10, 2017

Dr. Andreas Haldi was appointed as CYNORA's Chief Marketing Office in 2016. CYNORA develops efficient blue TADF OLED emitters, and Dr. Haldi was kind enough to participate in this interview and help us understand CYNORA's business and technology.

Cynora Blue TADF OLED material photo

Q: Thank you Andreas for helping us understand CYNORA's business and technology better. CYNORA has set up on a focused mission to develop a commercial blue TADF emitter. What will you consider to be a market-ready material, in terms of lifetime, efficiency and color point?

For the last 5 years, CYNORA has worked on developing thermally activated delayed fluorescent (TADF) OLED emitters. End of 2015 we started to focus on efficient blue materials, which are still a key issue for OLED displays. Compared to the red and green pixels, the blue pixel is much less efficient. An increased efficiency of the blue pixel would therefore significantly reduce the power consumption of the display.

Kyulux - Hyperfluoresence OLED emittersKyulux - Hyperfluoresence OLED emitters