In its 2014 display tech forecast, research firm DisplaySearch predicts a 5.5-inch high-resolution screen could be an option for Apple's next-generation iPhone, as well as a possible AMOLED "iWatch" device.
Source: DisplaySearch
The DisplaySearch projections are merely speculation, but the firm has seen some success in predicting Apple's hardware moves. As such, AppleInsider offers the following information for purposes of discussion only.
The firm is eyeing at least two displays as possible candidates for the "iPhone 6," reports CNET. A lower end option would be a 4.7-inch unit with a resolution of 1,600-by-900 pixels that equates to a density of 386 pixels per inch. This would result in a more pixel-dense display than the current iPhone 5s' 4-inch 1,136-by-640-pixel screen, but keeps the 16:9 aspect ratio, an important feature for app continuity.
On the high end, Apple could employ a huge 5.5-inch display with a resolution of 1,920-by-1,080 pixels, yielding a pixel density of 407PPI. This unit would be built on low-temperature polycrystalline silicon (LTPS), a technology thought to be used in current iPhone 5s screens manufactured by Samsung.
As for the so-called "iWatch," DisplaySearch sees AMOLED as a viable option, which would be Apple's first use of the display technology. Specifically, the firm points to flexible 1.3-inch or 1.6-inch AMOLED units, each with 320-by-320-pixel resolutions for respective pixel densities of 348PPI and 278PPI.
Finally, a guess as to a larger iPad was tossed out, with the now imaginary tablet bringing a 12.9-inch display boasting a 2,732-by-2,048-pixel resolution.
Rumors from December said Apple was in fact considering a larger iPhone and 12.9-inch iPad for release later in 2014, though no hard evidence has surfaced to back up those claims.