The iPhone has had a 3.5 inch screen since its release. That probably isn't going to change.
Every app in the App Store is made with the loving fact that it will work on all iPod Touches and iPhones alike. Why is this? Because the screen sizes are all the same. Some apps have adapted for the retina display, some are still running on the resolution of the iPhone 3GS and older. They all have one thing in common; a 3.5 inch display.
So what is it that makes the iPhone's 3.5 inch screen a hit? That's an interesting question to think about. Especially since there are other phones selling high amounts with absolutely massive screens. The Galaxy S II, pictured above, has a screen that is almost an inch larger than the iPhone 4S's screen.
A designer, named Dustin Curtis has a very good speculation to put into perspective for all of us:
Originally Posted by Dustin Curtis
As indicated by the image above, the average thumb-span of phone users meets the criteria of of the green area when the phone is held in portrait position. As shown, most of the iPhone's screen is very accessible by the thumb when the hand is placed in a comfortable position on the phone. When the same is done on the larger screen, an average sized thumb won't be able to reach without some major extension or wrenching of one's hand.
On the iPhone, there are usually navigation buttons on both the top left and top right of the screen. It's nice to be able to reach both in a tight situation, although on the larger screen the top right navigation button would be inaccessible.
When holding the phone in landscape mode, two hands usually support the phone. So on a larger screen, both thumbs cover most of the area accessible to input data into the phone. In this case, landscape orientation appears to be good for both handsets. The weakness of larger screens is portrait mode where people generally don't use two hands unless it's necessary. It generally feels pretty awkward to hold a small device with two hands. I would find myself using two hands on a larger screen more so than on the iPhone; it seems like that would get pretty inconvenient if I was multitasking and needed my other hand.
I find myself many times using two hands when my arms are propped over a desk. When I'm walking, standing, or laying down, I mostly only use one hand. I think I'm pretty content with this screen size and I'm not sure I'd like a larger screen. The 3.5 inch screen seems to be great for ergonomics.
Where does the 'bigger screen' come to an end? What will happen if a company comes out with a 5.5-6 inch smartphone screen? Why not just buy a 3G tablet? Perhaps the most important question to ask, is, what kind of device are you looking for?
I would have to continue to support the iPhone's current screen size. How do you cope with your 3.5 inch iPod Touch or iPhone screen? Do you own a larger screen? If so leave a comment below on how this perspective made you think about your screen size!
Sources: Redmond Pie