You may recall John Gruber of Daring Fireball positing back in early February that the iPad 2 would likely carry over the original iPad's 1024 x 768 resolution, while a possible new high-end model -- an "iPad HD" of sorts -- could take us into retina display territory as early as late 2011. Of course, we now know that the first part of Gruber's report is true: the iPad 2 ended up shipping at 1024 x 768. As for the iPad HD noise... well, thanks to a new Samsung component, it's looking more plausible than ever.
Doubting the practicality of a tablet-sized display with "retina" pixel density? Cost is still an open question, but Samsung may have solved a potential power problem by announcing that it's developed a 10.1-inch 2560 x 1600 display using the infamous PenTile pixel arrangement. That works out to 299ppi, high enough to make individual pixels indistinguishable to the naked eye at a normal tablet viewing distance -- and using PenTile reduces total sub-pixel count by a third, which Samsung says equates to a 40 percent reduction in power draw.
Now, to be clear, this isn't the exact component Apple would use. Any higher-res iPad would almost certainly carry over the same 4:3 aspect ratio -- not the 16:10 ratio demonstrated here -- which means they'd need something along the lines of the 2048 × 1536 resolution that Gruber suggested in February. But more importantly, the fact that Samsung has pulled this off at a 10.1-inch size suggests it's ready for tablets, and it's one of the first tangible signs that an iPad HD is both practical and technically feasible.
At any rate, a longer-lasting battery isn't the only advantage -- PenTile also reduces cost while making it easier to miniaturize and produce displays at higher resolutions. Problem is, "PenTile" has become something of a bad word in the display business over the past year as owners of smartphones that use the technology -- the Galaxy S series and the Atrix 4G, to name a couple -- have discovered that the unique pixel arrangement has a tendency to tint grayscale images and reduce the quality of text rendering. Many (myself included) barely notice, but it's become a black eye nonetheless.
Fortunately, PenTile technology isn't standing still. Samsung-supported firm Nouvoyance has also been showing a 15.1-inch 816 x 490 RGBCW prototype that adds a cyan sub-pixel into the typical red-green-blue-white arrangement, combined with an RGB backlight capable of varying its color and intensity in localized parts of the screen. It certainly sounds like this would go a long way toward solving tint complaints, and it's safe to say that Apple won't be using a high-res tablet display with "retina" branding if it looks weak up against an iPhone 4. Oh, and don't worry about the size and low resolution of the proto: Samsung says the tech "can be readily scaled" as necessary.
As for availability, Samsung will be shipping displays with this technology "later this year" -- perfect timing for the next round of tablets, Apple and otherwise.