OLED Lifetime: introduction and market status - Page 15

When Samsung announced the Galaxy Note 2, with its 5.5" 1280x720 HD Super AMOLED display, I assumed it was a Pentile display. But it seems that the Note 2 actually uses an RGB matrix in a unique arrangement (see the photo below). Samsung calls this new matrix S-Stripe. This is rather confusing on several accounts - mostly because up till now Samsung used the brand Super AMOLED Plus for non-pentile OLEDs.

Just a few weeks ago we explained that Pentile OLED displays enable higher lifetime, and we were told that for an RGB OLED with over 230 PPI, lifetime becomes too low for Samsung and they choose Pentile in those displays. But the Note II has a PPI of 267 - the highest PPI non-Pentile OLED. This means it has a lower lifetime compared to a Pentile display (but the advantage is that there's no visible Pentile pattern of course).

A few months ago Samsung said that the new Galaxy S3 has a Pentile display (a 4.8" 1280x720 HD Super AMOLED one to be exact) because PenTile increased the lifetime of OLED panels. I have discussed this with Joel Pollack, an Executive VP at Nouvoyance (Samsung's company that developed the PenTile matrix scheme), and he explains this claim further.

An OLED display is made from colored (RGB) sub pixels. A blue OLED has the lowest luminous efficiency (lower then red and green) and so needs to be driven at higher current - which means a lower lifetime.

Densitron is launching new PMOLED panels that feature higher lifetime than previous models. The company now offers yellow PMOLEDs that feature 100,000 hours lifetime at 100 nits and 150,000 hours at 80 nits. They are also offering PMOLED in different colors, and they say that their OLED panels lifetime is now three times longer than it was when they were first introduced.

Verbatim started shipping the Velve OLED lighting evaluation kit back in May 2011, and last month they sent us a unit for review. This is the world's first (and only) color-tunable OLED lighting panel, and it's pretty exciting.

Dupont published some new OLED material specification, you can see them in the photo below. The lifetime (LT50) of their Blue fluorescent material is now over 33,000 hours (the the 0.14c0.13 blue, anyway) - which they say is good enough for OLED TVs. Their solution-processed materials are now more efficient than their evaporated-materials, but lifetime is probably lower (it's a bit hard to know since they only publish LT95 for those materials).

I had an interesting discussion with a Dupont employee involved in their OLED program. In January 2012 it was reported that the company is building a $30 million pilot production line for OLED TV displays using their new nozzle printing technology. It turns out that the report wasn't accurate - the facility that DuPont is building is a material production facility. They have no intention to start producing displays...

As I already said before, Ignis Innovation's SID booth was one of the conference highlights for me. Their technology is very impressive and hopefully will enable cheaper non-LTPS AMOLED production.

In their booth, Ignis were showing 3.5" and 20" AMOLED panels that use the company's a-Si backplane compensation technology. The panels were made by RiTdisplay. Ignis and RiTdisplay have been showing these displays back in 2011. Originally they were supposed to be released towards the end of 2011, but this never happened. During SID Ignis announced that now the plan is to release these by the end of 2012. According to Ignis the 3.5" AMOLED will be cheaper than the LTPS-based competition (i.e. Samsung made panels). You can read more about these panels and RiTdisplay's plans at my RiTdisplay-at-SID-2012 post.

Mitsubishi Chemical and Pioneer have jointly developed OLED elements produced using a wet coating process for the light-emitting layers. The two companies will establish a testing facility with an aim to commercialize this technology for OLED lighting mass production by 2014.

Mitsubishi's and Pioneer's OLED coating project began in January 2010, and in May 2011 the companies announced that they managed to fabricate a white OLED in which the emissive layer was formed in a coating process. That OLED featured 52 lm/W and a lifetime (LT50) of 20,000 hours (@1,000cd/m² luminance). The new panel produced now features 56 lm/W and a lifetime (LT70) of 57,000 hours (@1,000cd/m² luminance) which is quite an improvement.

My first meeting at SID was with Universal Display's Janice Mahon. UDC had some pretty interesting updates for us at SID, and some nice exhibits in the booth as well - only OLED lighting panels, but quite interesting ones. This post will be rather long...

Novaled have developed a new class of n-doped electron transport layer (ETL) materials, suitable for both OLED TV and small mobile display applications. Novaled have developed two new new air-stable dopants (called NDN-77 and NDN-87) and two new host molecules (called NET-164 and NET-142). Combining these different materials can lead to different efficiency, voltage and lifetime in the final display.

Novaled says that the new materials can feature as much as double the lifetime compared to their previous materials.

Nippon Seiki has entered the OLED lighting market, and is already producing and offering "low-priced" panels. Low cost is relative of course - the 90x90 mm panel costs ¥8,000 ($100). The company is now offering samples because they want to get user feedback to improve the technology and products.

NS are currently offering three kinds of panels: a 90x90 mm square, a 280x38 rectangle and a 140x38 mm rectangle. All the panels are 1.9mm thick and feature 30,000 hours lifetime (LT70). The brightness is 1,000 cd/m² (maximum 3,000 cd/m²) with color temperatures of either 3,000K or 5,000K.