Samsung: PenTile AMOLED displays last longer, that’s why we use them
Samsung announced its new Galaxy S III smartphone to great fanfare last week, though some observers weren’t terribly happy with one particular feature: the 4.8-inch 720p Super AMOLED display uses a PenTile subpixel layout instead of the generally more favorable RGB layout. At CTIA 2012, we spoke to Samsung about its choice to use PenTile layouts in a large number of its displays, and the answer really comes down to durability and longevity.
Ever since the original Galaxy S in 2010, Samsung has used AMOLED (usually branded as Super AMOLED or Super AMOLED Plus) displays in many of its high-end smartphones, and many consumers are big fans of them. AMOLED screens have tremendous contrast, very saturated and vibrant colors, and extremely wide viewing angles. Devices that feature AMOLED displays have a certain ‘wow’ factor when you first look at them, and many users appreciate that, even if the displays don’t provide the most accurate color reproduction. Samsung says that it fully believes AMOLED displays are the best for its mobile devices, and that’s why it uses them time and again.
However AMOLED isn’t without its faults. Displays that use AMOLED technology have a tendency to deteriorate over time. One doesn’t have to look back that far to remember the problems Google had with the original Nexus One smartphone, which featured an AMOLED screen. There were numerous reports of screen deterioration after only a few months of use, and in some cases the display was rendered unusable (HTC, the maker of the Nexus One, eventually switched to using Super LCD displays in later versions of the phone, though it cited supply constraints as the reason for the switch).
Samsung’s Philip Berne explained to me that the blue subpixels on AMOLED displays actually degrade the fastest – quicker than the red or green subpixels. With a PenTile layout, the subpixels are arranged RGBG (red, green, blue, green), so they feature more green subpixels and fewer red or blue subpixels than an RGB stripe layout with the same resolution. Because of this, AMOLED displays that have the PenTile layout tend to have a longer lifespan than those with RGB layouts. Since Samsung is selling its phones to users that usually keep them for 18 months or longer, it has to be sure that the display will still offer peak performance at that time. According to the company, PenTile AMOLED displays have proven to be more reliable than those with RGB layouts.
Those that have issues with the PenTile arrangement usually complain that the screen does not look as crisp as an RGB display or that there is odd color fringing along the edges of images, such as app icons. While Berne did agree that the PenTile arrangement’s faults are pronounced at lower resolutions, such as qHD or WVGA, high-resolution displays hide the problems due to the sheer density of pixels. The Galaxy S III and the Galaxy Note, for example, both feature high-resolution Super AMOLED displays with PenTile subpixel arrangements (the Galaxy S III has a 1280 x 720 pixel screen, while the Note has a 1280 x 800 pixel display). Under a microscope, one can see the pixel layout on these displays, but in real-world use, it is not visible to the vast majority of users. To that point, the Galaxy S II, which had a lower-resolution WVGA (800 x 480 pixel) display, featured an RGB layout for its subpixels.
Today’s choice to use PenTile in its high-end Super AMOLED displays doesn’t mean that Samsung isn’t working on or won’t develop future AMOLED displays that use the RGB pixel layout, provided it can maintain reliability across the board. In fact, the Samsung Galaxy Tab 7.7 tablet features a 7.7-inch Super AMOLED Plus display with 1280 x 800 pixels and an RGB pixel layout, though that screen is obviously larger than what we see on smartphones, thereby making any PenTile-related issues more noticeable.
Is the PenTile subpixel layout something that should be a concern for prospective buyers of the new Galaxy S III? We really don’t think so, and in our hands-on time with the device, we really could not see any issues with the screen. Trust me, I tried. Berne did point out that the 4.8-inch display on the Galaxy S III is improved over the 4.65-inch 720p Super AMOLED screen used on the Google Galaxy Nexus, as it features smaller gaps in its subpixels matrix, further minimizing the fringing effects of the PenTile layout.
Some reviewers and users may disagree, and contend that “once you see the PenTile, you can’t unsee it,” but we really think that the average smartphone buyer (the people that Samsung is actually selling the phone to) will never be the wiser. Additionally, as smartphones get higher and higher density displays, the argument over PenTile and RGB subpixel layouts will become less and less relevant. Are we going to be discussing this matter when smartphones with 1080p displays, perhaps some with PenTile subpixel layouts, come out in the next year or so? We really doubt it.