PPI - Page 16

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.

Japan Display (the new small/medium display maker that merged Sony, Hitachi and Toshiba's businesses) announced it will join Kyushu University OPERA center in its OLED research project.

The OPERA center (or the Center for Organic Photonics and Electronic Research) project (titled "Challenges for superior organic EL devices and innovative materials for the devices") is very broad - from basic research to application and development, including synthesis of new luminescent materials, device fabrication and elementary technology for display panel production processing.

Update: according to the english version of the article, the 350ppi was achieved "in the lab", so it's not clear how close this is to commercialization. The article also suggests that Samsung is indeed moving away from LITI...

There's a report from Korea suggesting that Samsung managed to reach 350 ppi on an OLED display using FMM (Fine Metal Mask). Up until now Samsung focused on LITI to reach such high resolutions, but if this is true then Samsung can quickly apply this production process to their current AMOLED fabs.

Hopefully we'll hear more of this achievement if true soon. One of the major advantages of current LCDs over OLED panels is the higher possible density (Apple's Retina display for example reaches 326 ppi), so this may be a huge boost for OLEDs.

AUO's president, Paul Peng, reiterated the company's plans to start AMOLED mass production in Q3 2012. AUO will make 4.3" panels featuring 257 ppi. Peng also reveals that the company is co-developing in-cell touch AMOLED panels together with some handset makers, and will have samples ready by H2 2013.

There are also reports that AUO plans to introduce large-size OLED panels by the end of 2012. The company is reportedly working in cooperation with Japan-based firms to develop those panels. The AMOLEDs will be produced in AUO's 6-Gen R&D line and be based on Oxide-TFT backplanes.

RIM is getting ready to launch their new BlackBerry 10 operation system and the first devices that use it. A new leaked slide suggests that the new N-Series (with the QWERTY keyboard) will feature a square 720x720 2.8" AMOLED display. The pixel density is high at 330 ppi (it's likely that it uses Pentile tech). CMI has shown 326ppi OLEDs as well, but they will not have the capacity needed for RIM).

Apparently the N-series will be released in Q1 2013. Although this is a rather small AMOLED displays, it'll be great to finally see the first Blackberry with an OLED. Note that the slide says that future N-Series generation may revery back to LCD panels.

Just before SID, the Flexible Display Center (FDC) at Arizona State University (ASU) announced that they managed to fabricate the world's largest (7.4") flexible (bendable) OLED using Mixed-Oxide TFTs. Those MO-TFTs deliver high performance (fast switching speeds and reduced power consumption), are quite cost-effective and can be produced on existing a-Si production lines. The FDC demonstrated this panel at SID.

This OLED panel was developed with funding from the US Army features 480x360 (81 ppi) resolution, has an Oxide-TFT (IGZO) backplane and is built on a PEN (polyethylene naphthalate) substrate. It was developed in collaboration with Universal Display, DuPont (Teijin film), Sunic and Henkel.

Chimei Innolux had a nice booth at SID 2012, and I was given a nice tour of the booth by their PR people (who allowed me to take photos and videos even though they had a sign saying it ain't allowed). CMI's marketing guys were also kind enough to answer a few questions I had on their OLED program.

A few days before SID CMI announced that it will begin to produce 3.4" and 4.3" panels by Q4 2012. At SID I learned that the first OLED fab to go online is actually an old TPO/Toppoly 3.5-Gen fab. The panels will use LTPS backplane and will both feature 960x540 resolution (so it's 326 ppi on the 3.4" panel and 257 ppi on the 3.4" panel). CMI says that their technology is "ready" for 4.5" 720p (326ppi) panels as well.

Sony released 0.5" 1024x768 (2,560 ppi, 9.9um pixel pitch) and 0.7" 1280x720 (2,098 ppi, 12um pixel pitch) OLED microdisplays back in August 2011, and now they gave some interesting details about the technology used to fabricate those panels. The 0.5" OLEDs are used in several 'A' class digital cameras, and the 0.7" microdisplays are used in the HMZ-T1 HMD device.

We already know that the microdisplays use white OLEDs with RGB color filters (all OLED microdisplays on the market use this architecture, although eMagin are working on direct-emission ones). Sony are using stacked RGB fluorescent materials. They say they did not choose red and green PHOLEDs because of lifetime, reliability and cost considerations.

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.