When it comes to screen sizes and real estate, we’ve seen anything from a paltry 2.8-inch display to enormous 5.2-inch screens on Android phones, but with the iPhone, the screen has remained at a constant 3.50-inch diagonal through successive generations of the Apple smartphone. Various reasons are given from for the iPhone’s consistent display real estate, including ease of use with the smaller form factor, pixel density for higher resolution displays with the Retina Display, and personal preferences of Apple designers and engineers for the more pocketable display. However, there may be one reason why Apple is going smaller rather than larger, and that reason may be the reach of the thumb when holding the phone in one-handed use.
According to designer Dustin Curtis, the iPhone’s 3.5-inch screen is perfect and comfortable enough when held and used in single-handed mode. When you rest the smartphone on your fingers and reach your thumb of the same hand over the display, the extension of your thumb can comfortably span the entire display, allowing you to perform simple taps and touches with a single hand, rather than double-handed usage where you’d have to hold the phone with one hand and use the opposite hand to operate the screen.
Touching the upper right corner of the screen on the Galaxy S II using one hand, with its 4.27-inch screen, while you’re walking down the street looking at Google Maps, is extremely difficult and frustrating. I pulled out my iPhone 4 to do a quick test, and it turns out that when you hold the iPhone in your left hand and articulate your thumb, you can reach almost exactly to the other side of the screen. This means it’s easy to touch any area of the screen while holding the phone in one hand, with your thumb. It is almost impossible to do this on the Galaxy S II.
With larger devices–devices with 4-inch and larger screens, the thumb span doesn’t reach entirely across to cover the entire screen, leaving areas of the far edge of the screen where a user would have to hyper-extend their thumbs to reach.
While Apple has not deviated from the 3.5-inch screen size, there are numerous speculations that Apple will experiment with a 4-inch display on the iPhone 5. With a 4-inch display, Apple would have to employ yet an even higher resolution screen to keep the Retina Display moniker intact. The company defines Retina Display as having pixels that are not discernable by the naked eye, and even the smallest of text can be read. With a display any larger than 3.5-inch utilizing the same 960 X 540-pixel screen, smaller text would appear pixelated. On the Atrix 2′s non-PenTile qHD 960 X 640 screen distributed over a 4.3-inch display, I noticed that text and images, although sharper than a PenTile-based qHD display, is no where near as sharp as the Retina Display. Going to a larger screen with the same resolution would mean that Apple would not only have to sacrifice some elements of single-handed usability when operating the phone, but also crispness in display.
Another rudimentary, albeit overly simplistic, explanation of why Apple chose to settle on a 3.5-inch display is that the trend at the time that the original unibody aluminum iPhone launched, display sizes tend to fall under the smaller 2.8-inch form factor, popularized by the HTC Touch Diamond, or the larger 3.5-inch form factor on larger Windows Mobile phones. Display sizes started larger at 3.5-inch QVGA resolution on the very first Pocket PC phones, but manufacturers began to popularize on smaller form factors, such as the 2.8-inch display. Realizing that smaller sizes weren’t as conducive towards touchscreen unless users always used a stylus to make their input, manufacturers inched upwards again towards 3.5-inch. The Touch Pro 2, one of the last Windows Mobile phones, employed a 3.6-inch WVGA display alongside with a sliding QWERTY keyboard.
Via: The Next Web