OLED ink jet printing: introduction and market status - Page 27

The UK's printable electronics technology centre (or PETEC) has received a 20M GBP (about 32M$) investment from the UK's government and a regional fund (One North East). PETEC will double its facilities, hoping to begin a 15 billion GBP UK industry.

TOPLESS project OLED lamp prototype

PETEC is working on several projects, including OLED displays and lighting and solar panels. One of these project is TOPLESS, working on OLED lighting. PolyPhotonix, who are working on OLED light therapy, are opening a production line at PETEC.

Solterra Renewable Technologies (wholly owned subsidiary of Hague Corp) today announced an exclusive worldwide licensing agreement with the University of Arizona for the patented, intellectual property covering screen-printing techniques for OLED fabrication. Solterra's CEO Stephen Squires says that there are essential similarities between the screen-printing techniques to fabricate LEDs and the screen printing technology that Solterra is currently optimizing to print quantum dots to make thin-film solar cells.

Dai Nippon Printing (DNP) has made a new PMOLED panel using gravure printing technology. DNP used P-OLED inks, on a glass substrate. The drive voltage of the OLED panels is 12V, with a luminance as high as 100cd/m².

DNP gravure-printed PMOLED

DNP made two prototypes (shown above) - 192x32mm (32x192 resolution) and 110x37mm (32x96 resolution). Both are 1.4mm thick.

CDT is one of the leaders in OLED research, focusing on Polymer-based OLEDs (PLEDs, also called P-OLEDs). While these OLEDs are lagging behind small-molecule OLEDs in current products (all AMOLEDs today are based on SM-OLEDs), some companies believe that PLEDs are actually the better tech for the future.

CDT's CEO, David Fyfe has agreed to answer a few questions we had on CDT's technology. David joined CDT in 2000 as Chairman and CEO. David saw CDT go public in 2004, and then negotiated the sale of CDT to Sumitomo for $285 million (in September 2007). David is also a director of Soligie, an electronics printing company, Acal Energy, a fuel cell technology developer and the Plastic Electronics Foundation.

Q: David - thanks for agreeing to do this interview. Since the Sumitomo acquisition, CDT has been rather quiet... can you give us an update on where's the company now, and where's it is headed?
Since the merger of CDT into Sumitomo Chemical in September 2007, CDT has grown substantially and received considerable capital investment to enable it to remain a leading developer of PLED technology. It works very closely with SCC laboratories in Japan and most recently has been transferring manufacturing process knowhow to SCC's own PLED manufacturing development line, recently commissioned at Ehime on Shikoku, Japan. CDT in partnership with SCC has made large strides in materials lifetimes and efficiencies. SCC prefers to take a lower profile in announcing these advances since its business model is to work with selected display maker partners in a collaborative, confidential relationship. We have also made big strides in the development of top emitting structures and in printing PLED displays. SCC's strategy is that CDT will continue to be its leading development center for PLED technology with Ehime scaling process technology to a yielding process status. CDT is also working very closely with Semprius of North Carolina, USA to develop single crystal silicon TFT structures on which PLED devices can be deposited and driven using Semprius’ proprietary stamping technology.

Q: It seems that OLED displays are finally entering the mainstream - we hear of new devices (mainly by Samsung, but also from Sony, Microsoft, LG and others) almost daily. What are your thoughts on this? what are the challenges that still exist for OLEDs?
Sony broke the logjam of resistance to the adoption of OLED in large displays by major display makers with the introduction of its XEL-1 11 OLED TV in 2007. Samsung SDI’s investment in small screen OLED production in 2007, based on LTPS backplanes was another major impetus. Since then, Chi Mei has brought on small OLED screen capacity, TMD (now wholly owned by Toshiba) has built an OLED line to manufacture small screens, LG Display will start up their Gen 3.5 line late this year and if press reports are to be believed, Toppoly will commission their capacity with Nokia as a lead customer and Panasonic have a major OLED development program for large OLED displays.

Last month Seiko Epson has unveiled a new inkjet-printing technology for OLEDs, suitable for large sized panels. We have talked to Satoru Miyashita, General Manager of Seiko Epson's Core Technology Development Center about this new technology and their plans for OLED production.

Q: You have shown a new ink-jet based OLED technology. You say it will enable 37" or larger HD-OLED TVs. Do you have any plans to actually make such TVs? When do you think products can be made with this new tech?
Epson is currently considering a variety of options regarding the commercialization of this technology, but at this point no specific announcements have been made about plans. We see 2012 as being the year that 37"+ OLED TVs will be launched by various makers, and 2015 as the year that sales will really take off for this market.

Espon 14-inch Inkjet processed OLED

Bayer MaterialScience AG, a unit of Bayer AG, signed a technology and patent license agreement with Add-Vision. Bayer will be able to manufacture and sell flexible Polymer based printable OLEDs. 

Bayer says that the technology is an important component for many applications in the coming years - such as active packaging and labels, gift cards, electronic toys and games, promotional products or point-of-sale signage.

Financial details have not been disclosed.

A few years ago, lifetime was the biggest issue with OLEDs, but it seems companies are showing very rapid advances. Dupont announced today that they developed new (third Generation) printable, solution process OLED materials.

The Green Gen3 material has over one million hours lifetime (that's over 100 years of constant use!) with 25 cd/A efficiency. The color coordinates are 0.26, 0.65. 

The light-blue Gen 3 (color coordinates 0.14, 0.12) has 38,000 hours from 1000 cd/m2, efficiency of 6.0 cd/A, and a lifetime of 38,000 hours. A deeper blue (color coordinates 0.14, 0.08) was developed with 7,000 hours. Due to its deep blue color, the lifetime of this material at the luminance required for a 200 cd/m2 display is calculated to be approximately 41,000 hours. 

The Gen-3 red has a lifetime of 62,000 hours, current efficiency of 13 cd/A, and color coordinates (0.68, 0.32). 

Seiko Epson today announced that it has developed a new inkjet technology that enables uniform deposition of OLED materials in large size displays. They believe that this is a major step towards 37" (or larger) HD OLED TVs.

Espon 14-inch Inkjet processed OLED

Seiko Epson claim this is the first technology that can reliably form uniform organic materials on large substrates. The most widely used tech today, Vaccum Thermal Evaporation (VTE) is not able to do it because of several technical issues.

Epson has recently developed the long-awaited solution in the form of
an OLED display fabrication process that leverages the company's
proprietary Micro Piezo inkjet technology to achieve markedly greater
accuracy in organic material deposition than the conventional
technology. The process has been used in trial production to fabricate
a highly uniform prototype panel. Extremely uniform layers (volume
error ejection of multi-size droplets of ink material on a substrate so that
only the required volume of material is deposited.

Epson will give more details at SID, together with a 14" prototype display (shown above), that has a HD resolution.

Last week we reported on Polymertronics - a new company that's working on an OLED plaster to cure skin related diseases. Now we have some more information and a nice new photo.

Polymertronics OLED plaster

Polymertronics are making their own Small-Molecule OLED materials, called OLED Red Diamond. One of the formulation can actually be printed via inkjet, and is also UV curable. That version is cross-linkable polymer.

They acknowledge the fact that using an array of OLEDs, rather than a single large one is more complex, but they say it does have a number of benefits.

Polymertronics are also working on the electronic interface of the OLEDs, and claim to icnrease the lifetime of the OLEDs by several orders of magniturde using a 'clever design'.

Lumicure, the 2nd UK company working on a similar device, is using one 'large' OLED panel.

Agfa, Philips and the Holst Center are showing a large-area (12x12cm2) flexible OLED - without ITO as transparent electrode, and with printed shunting lines. This means that costly materials and lithography processes are not needed, and the OLEDs are much cheaper.

Flexible OLED lighting prototype with no ITO

Up till now, ITO was needed as supporting layer for the PEDOT/PSS* anode layer with lower conductivity. Thanks to Agfa’s high-conductive transparent polymer OrgaconTM, a PEDOT/PSS-based solution with six orders better conductivity than its predecessor, the use of ITO can now be avoided. Proof is the latest OLED lighting demonstrator of Holst Centre’s shared programs: a homogeneous white OLED tile of 12x12cm2 without the use of ITO.