Solution based OLEDs - Page 16

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

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). 

Panasonic has announced that they are developing OLEDs together with Sumitomo. They aim to make 40" (or bigger) TVs by 2010. Back in 2008, Sumitomo announced plans for OLED TVs by 2009, and were seeking partners for doing it.

Sumitomo's technology is based on CDT's PLED materials (CDT were acquired by Sumitomo back in 2007).

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.

Panasonic is working on OLED lighting panels, using printing methods. They prototypes a high efficiency panel at Printable Electronics 2009.

The OLED lighting panel features a luminance efficiency of 40lm/W and a CRI (color rendering index) value of 95. The external quantum efficiency is 36.1%, and the half-life of the luminance exceeds 20,000 hours when the initial luminance is 1,000cd/m^2.

Read more at TechOn

Merck is a global pharmaceutical and chemical company based in Germany. The company designs, develops and manufactures a wide range of specialised materials including high performance light emitting materials for OLEDs. The OLED business belongs to Mercks' Liquid-Crystal (LC) unit.

I managed to conduct an interview with Dr. Udo Heider, the VP of the LC business unit at Merck (it's called the LC/OLED unit) about their OLED program.

Q: Hello Dr. Heider, and thank you for this interview. Can you describe your range of OLED products in more detail? Are you just into OLED materials, or other IPs as well?

Plextronics announced today that its conductive ink has been shown to improve the performance of certain PLED devices.

The research team at GE has put together a cool OLED christmas tree. The OLEDs were made by a roll-to-roll fabrication. The OLED is 6 inch wide, by 15 feet. Here's a nice video of the tree:

Anit Duggal, who's leading GE OLED program said - We’re making great progress toward hitting the metrics needed to successfully introduce OLED lighting to market. We continue to make steady advances in efficiency, lifetime, and lighting-quality using device structures that can be made with roll-to-roll manufacturing, so that we’ll be able to introduce OLED lighting at an affordable price.

We also got a nice high resolution picture of the tree:

Cambridge Display Technology (CDT) will develop a new technology to make OLED backplanes, together with Semprius. The new tech will be integrated into CDT's 14-inch development line at Godmanchester campus, near Cambridge, UK.

Semprius has a technology for semiconductor printing, and the two companies will use the technology in the manufacturing of OLED backplanes.