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.
Samsung has rationalised the OLED interests of Samsung Electronics and Samsung SDI by the formation of Samsung Mobile Displays. In other words the major players are staking out an OLED future, some in small screens and some first in small and then targeting large screens (TVs).
Most recently, Seiko Epson has announced that it has “cracked” the issues around inkjet printing of OLED displays and is moving now to commercialise that technology in a business model that is not altogether clear but may well involve partnerships with other display makers.
The barriers that face OLEDs are as follows:
- Small molecule OLED materials performance seems to now be at a level that satisfies the majors BUT it is clear to most of them that while vacuum deposition of these materials thru’ shadow masks is OK up to Gen 4 substrate size, beyond Gen 4 it is impractical (indeed Samsung Mobile Displays, Chi Mei and LG are or will process using ½ cut Gen 3.5 or Gen 4 i.e masking the substrate in two separate operations. Nothing could more clearly show the limits of shadow masking. Thus display makers who aspire to make TVs from substrates of Gen 5.5 and larger are looking at printed solutions.
- While lifetimes and efficiencies for PLED are now sufficient for handheld device performance and both red and green lifetimes and efficiencies are fully acceptable for TV performance, blue still lags requirements in lifetime for TV. Given the current rate of progress this is expected to be no longer an issue within the next two years.
- There has been skepticism regarding the development status of inkjet printing equipment and print heads and fitness for large scale manufacturing. However, this is evaporating as experience grows of inkjet printing color filters in a number of display makers and Epson’s announcement at SID has kindled considerable interest. Dupont claims success with nozzle printing in partnership with Dai Nippon Screen.
Given the very superior characteristics of OLEDs compared to LCD and Plasma, I expect it only to be a matter of a couple of years before we see OLED TVs being offered by a number of industry players.
Q: You say that inkjet-printing OLEDs is the future, and printing SM-OLEDs is more difficult than printing PLEDs. Why is that?
Our view has always been that polymer bridging units would be essential to long life and high efficiency of emitters which dry from PRINTED droplets. We at CDT have spent the last three years bringing the lifetimes of inkjet printed PLEDs to the same level as spin coated PLEDs. Virtually all the data that is public for solution processed SMOLEDs is from spin coated data and what data is available from printed SMOLEDs suggests Dupont (and we have information - UDC also) is struggling with the same issue as we first addressed three years ago.
Q: UDC claims that 'virtually-all' AMOLEDs use their tech. When will we also see AMOLED based on your PLED tech?
All the commercial OLED at the moment is small molecule. UDC have been supplying the red material to Samsung, LG and maybe Chi Mei but not I believe to Sony. Rumor has it that their green material is finally acceptable (suffered from instability prior to this) and that Samsung will adopt to further benefit power consumption. Sumation has red and green polymer based material which is every bit as good as UDC 's vacuum deposited performance so it is just a question as to when the printing technology is deemed fit for mass manufacturing.
Q: Panasonic announced that they are teaming up with Sumitomo for OLED TVs. Will these be using PLEDs? When can we except a PLED TV on the market?
Panasonic officially denies that the press release was theirs but detail in it suggests it was.
Note - according to Nikkei.com, Panasonic has an extensive inkjet-printing PLED program. They aim to release PLED TVs at around 2012.
Q: TMDisplay is now focusing on OLEDs, after Toshiba bought out Matsushita's part. Are they working on PLEDs still?
Toshiba/TMD will be working on both SMOLED and PLED technologies. The Toshiba influence in TMD was always pro-PLED but I have not seen them since the demerger from Panasonic so am not up to date with the Toshiba strategy.
Q: Any updates on the Semprious JV on printing tech?
Semprius – making excellent progress in this technology of printing the TFTs (TFTs patterned on Si wafer then released by etching and lifted from mother wafer and stamped onto the OLED display substrate resulting in single crystal TFTs – ideal for OLED driving.
Q: I wonder what are your thoughts on OLED lighting - it seems like a very exciting application for OLEDs. Will CDT be a player in this market?
OLED lighting – yes we are putting substantial effort into materials development for this application (PLED white for example but also the RGB approach is being pursued by some lighting companies) Efficiency is the issue and in my view so will processing technology. Some believe that you cannot get the economics good enough with high-vacuum processing to compete in mass lighting markets – back to the same issue as confronts small molecule in the display field.
Thanks David for this interesting interview... I wish you and CDT good luck!