As Android smartphones continue to grow beyond any reasonable limits both in screen size and display resolution, pundits in tech blogs are becoming increasingly more vocal about Apple utilizing a bigger screen in the next generation of the iPhone. Although there are different opinions, concerning the screen size of the iPhone 5, the 4 inch screen is considered by many as the most “probable” candidate. Instead of size, I would like to touch the topic of screen resolution of that possible display.
The first and most simple scenario is just to keep the “old” resolution. Sure, Apple could bump the display size to 4 inches while keeping the same 640 x 960 resolution, introduced by the iPhone 4′s Retina Display — it would still deliver impressive pixel density, while avoiding creating any additional fragmentation to the iOS ecosystem. But this solutions does have a few downsides: every GUI element in iOS and it’s third-party applications wasn’t designed only for a specific resolution, but also for specific size — developers had a clear guide and knew that a said numbers of pixels would result in a particular physical size, simply because all this time iPhones had the same screen size. Having the same resolution represent another physical size will destroy this consistency, which can lead to worse user experience. That being said, in practice this problem could be virtually non-existent for the wast majority of applications. Then again, while Apple doesn’t see specs as the most important thing, it’s certainly isn’t in Apple’s best interest keed the same resolution, while it’s “competitors” are moving forward.
Changing the screen resolution is a far more interesting option. It’s safe to assume that Apple won’t go the whole iPhone 4 route another time and double the resolution again. Having a 1280 x 1920 pixel 4 inch display would result in pixel density of something like 577 ppi. Sure, technically it probably can be done (if not today then in a year or two), but such displays are no way near commercial viability and yield rates that are necessary for a mass-market device. Furthermore, this kind of display resolution would put a significant strain even on a next-generation mobile GPU.
So what are the other options? Maybe Apple can triple the resolution of the original iPhone, creating a @3x graphics mode (similarly to the @2x mode for the Retina Display in the iPhone 4 and iPhone 4S)? This would result in a 960 x 1440 pixels resolution with pixel density landing around 430 ppi. Application scaling would be relatively easy, as it was with doubling the resolution for the original Retina Display. Heck, if Apple were Samsung they could even call this “over 400 ppi” display something like “Retina Display Plus”. But such displays can still be a long way from yield rates that are acceptable for the iPhone.
In my opinion the most practical decision for Apple at this point is to introduce a new resolution, if the do indeed plan to release an iPhone with a bigger screen, but keep the ppi virtually the same, as the current iPhone. A resolution of 720 x 1080 pixels in a 4 inch screen would give Apple essentially the same ppi, as the Retina Display in the iPhone 4. This would not only allow developers to utilize the new screen size in the most effective way possible, but will also allow Apple to get the required screens without that many problems. Yes, this new resolution is 2.25 times bigger than the resolution of the original iPhone, so developers won’t get any magical super upscaling, but I truly believe that this can be solved with generic hardware upscaling — such minor upscaling (from 640 x 960 to 720 x 1080) would result in minimum blur, most of which probably wouldn’t be seen at such level of pixel density. And given the amount of them Apple will sell in the first days, most apps will support a new resolution without upscaling fairly quick. And the great marketing part in this? These displays can be called 720p!