PPI - Page 12

Chunghwa Picture Tubes (CPT) had some pretty interesting prototype OLED displays shown at the Touch Taiwan 2014 trade show last month. We do not have any information regarding how close are these prototypes to commercialization.

So first up is a flexible AMOLED display. This panel is 4.8" in size and 720x240 resolution (158 PPI). The company did not reveal any more technical details. The company also showed some simpler flexible PMOLED panels, demonstrating their sealing capabilities by immersing them under water (see image below).

OLEDNet posted an interesting article saying that Gionee's upcoming GN9005 ultra-slim smartphone uses a 4.8" HD AMOLED Panel (306 PPI) made by AU Optronics. OLEDNet says that the fact that this panel is called "AMOLED" and not "Super AMOLED" like SDC's panels is a hint, and in addition, it is a low-performance panel compared to the SDC-made 5" FHD 441 PPI panel Gionee used in their previous phone (the Elife S5.5).

I'm not sure I'm convinced - this panel could still be made by SDC, even if it does not specifically use the Super AMOLED brand (this is up to Gionee I believe to decide). But OLEDNet says that according to their information, AUO started supplying AMOLED Panels to a Chinese maker last month.

DisplayMate posted yet another interesting display shoot-out, this one testing Samsung's new QHD (2560x1600) Super AMOLED displays used in the upcoming Galaxy Tab S (8.4 and 10.5) tablets. As these displays are very similar to the GS5 display, it's not surprising that DisplayMate found those tablets to offer the best performing displays ever. This is yet another testimony to how great OLED displays are - and the rate of improvement in OLEDs is very rapid.

As DisplayMate found out, the Galaxy Tab S establishes new records for best Tablet display performance in: Highest Color Accuracy, Infinite Contrast Ratio, Lowest Screen Reflectance, and smallest Brightness Variation with Viewing Angle. These are also the highest resolution tablets at QHD.

In January 2014, SDC confirmed that it is developing a QHD (2560x1440) AMOLED panel. Today the company announced a new phone for the Korean market, the Galaxy S5 LTE-A which sports this new 5.1" QHD panel. This panel reaches a very high PPI (577) which makes it the world's highest density AMOLED, and probably the highest density mobile display (beating LG's G3 display which is a 5.5" QHD LCD, 538 PPI).

We don't know much about this display, but it probably uses some kind of Pentile display (or Diamond Pixel like the GS5). While this phone will probably be exclusive for Korea (it will be released via SK Telecom later this summer), hopefully Samsung will also release a similar upgraded GS5 phone with a QHD panel worldwide. It's also likely that the Note 4 will sport a QHD panel too. Samsung, by the way, does not plan to stop QHD. The company is actually developing a UHD mobile display - that will reach 870 PPI (!).

As we reported back in February, SEL and sharp unveiled a 13.3" 8K OLED prototype. This ultra high density (664 PPI!) display uses SEL's C-axis-aligned crystalline oxide semiconductor (CAAC-OS) backplane.

SEL's previous 13" CAAC-OS OLED prototype featured 326 PPI. But that lower-resolution panel was flexible. This new panel uses white OLEDs with color filters. SEL adopted micro cavities to narrow the wavelengths. The display features a 84% NTSC color gamut (rather low for an OLED). Each OLED pixel is driven by five transistors and one capacitor (5T+C) - there are almost 500 million pixel transistors in this display.

Semiconductor Energy Laboratory, in collaboration with Nokia developed a new foldable OLED display. The companies are demonstrating two display prototypes. Both displays are 5.9" in size with a 1280x720 (249 PPI) resolution. One of them can be folded in two (like a book) and the other can be folded in three (seen in the video below).

Those flexible OLED displays use a white OLEDs with color filters (WOLED-CF) design. To produce the display, SEL deposited the organic and color filters layers on a glass substrate, which is later peeled off and replaced with a flexible substrate. The displays can be bent up up to a curvature of 2 mm (two-folds) or 4 mm (three folds). SEL says that these displays can be bent more than 100,000 times.

Japan Display's OLED R&D manager Masahiko Suzuki discussed the company's AMOLED program during a conference in Japan. Masahiko explains (see slide below) that for the medium-term, the small/medium display maker is focused on high-res LCD panels (over 500 PPI), but for the long term the main focus will be on OLED displays.

JDI sees OLED as a way to create a new market for flexible, transparent and roll-to-roll printed displays. JDI is set to develop flexible OLEDs and later on high-resolution OLEDs. JDI is using LG's WRGB technology which enables them to achieve a high resolution and a lower power consumption on mainly-white images (such as a web browser). But currently JDI sees OLEDs as still too expensive, and there are still issues with lifetime and uniformity.

Visionox developed a new RGB pixel arrangement for OLED technologies that allowed them to reach 570 PPI. The company refers to this new technology as Z-Type arrangement and it includes 3 sub-pixels (RGB) per pixel (unlike Samsung's Pentile displays). The sub-pixels are densely packed (the aperture ratio seems very high) in a way that does not suffer from jagged edges.

Visionox told me that they cannot yet say when such displays can be commercialized, as there are still manufacturing challenges to overcome. In the meanwhile the company applied for both Chinese and international patents.

AUO announced that they developed a new 5.7" WQHD (2560x1440, 513 PPI) AMOLED panel. The panel is ultra slim at 0.57 mm and it uses special driver design to increase touch sensitivity and as a result can support 10 touch points.

AUO says that this is the world's highest resolution AMOLED. Actually we know that Sharp, and SEL developed a 13.3" 8K CAAC-OS OLED that achieves 664 PPI - but this one hasn't been unveiled yet (it will be shown at SID 2014 in a couple of months). In addition Samsung Display announced a while back that they are developing a 5.2" WQHD panel which will have a pixel density of 560 PPI. Reportedly SDC is also planning to make a UHD panel that will have a PPI of 860 (!).

Korean news site ETNews posted an article discussing Samsung's and LG Display's flexible OLED display plan for 2014. According to the report, LG Display will focus on reducing the size of the OLEDs while increasing the resolution and other display aspects, while Samsung wants to develop new display designs and forms.

LG Display is currently producing a 6" 720p flexible OLED panel - which means a PPI of 245. Samsung's display (5.7", Full-HD) has a much higher PPI of 386. In 2014, LGD hopes to start producing a 5.5" Full-HD panel. The company also reportedly has issues with heat handling and they want to address this issue.