OLED Lifetime: introduction and market status - Page 20

The OLED100.eu project is a European 3-year OLED lighting project. The 30M$ project is a followup to the OLLA project, ended in June 2008, and it is lead by Philips, OSRAM, Siemens, Novaled and the Franhofer IPMS.

Dr. Stefan Grabowsky, the project's manager has been kind enough to talk to us, answer a few questions and give us more info on the project. Dr. Stefan has a Ph.D in Physics,  from the University of Duisburg. In 2000 he joined Philips Research labs. He's working on OLEDs for several years now, with a focus on device physics and OLED stack development. Since September 2008 he is the project manager for OLED100.eu.

Q: Stefan, thanks for taking the time to do this interview. Can you tell us a bit about OLED100.eu?
OLED100.eu is an European integrated research project that has brought together a consortium of experts from leading industry and academic organizations to accelerate the development of organic light-emitting diode (OLED) technologies. It has received €12.5 million funding from the European Community’s Seventh Framework Programme to form the technological basis for efficient OLED applications for the general lighting industry in Europe.

Large-area OLED from Philips

Universal Display and Seiko Epson have been working on their inkjet printable, phosphorescent
OLED technology and materials for quite some time... They have now announced new advances in performace:

• A red P²OLED
  with CIE (0.67, 0.33), an efficiency of 10 candela per ampere (cd/A) and
  an operating lifetime of 20,000 hours, to 50% of initial luminance of
  1,000 nits


• A green P²OLED with CIE (0.33, 0.62), an
  efficiency of 34 cd/A and an operating lifetime of 25,000 hours.

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

Novaled and Kodak have developed  anew white PIN OLED, to be used in RGBW displays. The display is based on Novaled's p-type and n-type doped transprot layers and Kodak's emitter systems. The companies showed two devices - single unit and tandem-white OLEDs. 

For the single unit devices, 15.8-cd/A with a lifetime of 30,000 hours and color coordinates of 0.32/0.35 at 1,000 candelas per square meter were reached. In the tandem device approach a current efficiency of 33.2 cd/A at color coordinates 0.28/0.31 was achieved. The lifetime of the device was 77,000 hours compared to 51,000 hours that were reached with devices based on conventional Li-doping for the connector unit

In a display simulation the tandem device compares favorably with a conventional tandem device based on Li-doped p-n connectors; allowing display lifetime to be improved from 38,000 to 53,000 hours.

Universal Display and Samsung Mobile Displays present advances in green Phosphorescent OLEDs at SID. This new material will be used in both hand-held devices and OLED TVs, extending lifetime and efficiency. UDC's red materials are already used in Samsung's AMOLED displays, and it's likely that we'll see Samsung use their green materials as well.

The companies showed a highly-efficient, green
UniversalPHOLED material that has been used in a top-emission PHOLED
device architecture. Using this approach, they achieved two
milestones. A green PHOLED with NTSC color at CIE(0.20, 0.73), high
luminous efficiency of 110 candelas per Ampere (cd/A), and a low voltage
of 3.6 V at 3,000 candelas per square meter (cd/m2) was
achieved.

A second device structure using this green PHOLED material
system also achieved an ultra-high luminous efficiency of 160 cd/A along
with CIE(0.28, 0.69) and low voltage of 3.8 V at 3,000 cd/m2.
These compare to a standard bottom-emission device with CIE(0.33, 0.62)
and 52 cd/A using this same green PHOLED material system. Replacing the
green fluorescent OLED material typically used today in an AMOLED with
this new green PHOLED can result in a significant 37% power savings.

The operational lifetime for this green PHOLED material system is also
very good. A bottom-emission device using this material system offers >
300,000 hours to 50% (extrapolated) and 15,000 hours to 90% of the
initial luminance of 1000 cd/m2 (defined as LT90). With these
top-emission devices, the LT90 lifetime is 28,000 hours and 6,400 hours,
respectively, for the 110 cd/A and 160 cd/A devices.

Toshiba Mobile Displays (TMD) shows a new 4.15" AMOLED display. The panel has a 60,000 hours at 200cd/M2. The display uses small molecule OLEDs with a top-emission structure. There's no word when such panels will be available...

We also hoped to hear more of TMDisplay's OLED TV program (TMDisplay are working towards HDTVs together with Panasonic), but I guess we'll have to wait some more...

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). 

Novaled, Fraunhofer IPMS and Optrex Europe developed a new, unique PMOLED driver. They have implemented an innovative MLA scheme called SELA (Summed Equiline Addressing). Basically, instead of driving using a single-line addressing scheme, the SELA allows parallel driving of multiple rows, thus preventing high current amplitudes.

Basically this means that we get higher lifetime, better resolution and better efficiency in the OLED display. The driver is specified for operations between -40°C and +125°C, exhibits an OLED drive voltage up to 25 V, and a column source current up to 2 mA. In particular the latter can currently not be fulfilled by any commercial available PM OLED driver.

In addition to the innovative addressing concept and the new OLED MLA driver, a high temperature stable and long-living orange emitting PIN OLED layer stack was developed by Novaled AG. In automotive applications high reliability at 85°C
operational temperature and highly stable brightness (often only 20% reduction over lifetime is allowed) is required. The newly developed OLED stack offers an operating lifetime of currently 5.300 hours at 85°C and 20% brightness drop at an initial brightness of 600 cd/m².

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?

We've got some more info on LG's 15" OLED TV, shown at CES. The screen is 1.4mm thick, and expected to go into production in June. The resolution is 1366x768, and the reported lifetime is 30,000 hours.

LG 15" AMOLED at CES 2009

LG will not release this as a 'luxury' item (like Sony's XEL-1, priced at 2500$). They are waiting for customers to put this in laptops, and only then will they begin producing the displays. here's a short video showing this cool prototype.