iPhone Touch Screen Interface

The touch interface of the iPhone is a touch screen that can be used with a stylus or just the fingers. The screen’s resolution is 320 by 480 pixels and measures 3.5 inches.

The display has three sensors. The first is the proximity sensor, which allows automatic turn-off the moment the phone is placed near the user’s ears or face. This is to lengthen the life of the battery and to avoid spurious input from the face and ears of the user. It also has a 3-axis accelerometer sensor for auto-rotate, that is able to sense the phone’s orientation so it can accordingly change the screen. The third one is the ambient light sensor, which adjusts the brightness of the display, depending on the surrounding light quality. Music playing and Internet browsing can support the three screen orientations, although videos can only be viewed in the wide screen orientation.

There is a “home” hardware key located below the display screen that will bring up the main menu. Sub-selections can then be made using the touchscreen. The iPhone displays full pages with the specific sub-menus located on the upper or lower portion of each page, depending on the orientation of the screen. The more detailed pages have an equivalent “back” key that will enable the user to go up a step in the menu.

There are three switches on the sides of the iPhone. These are the sleep/wake switch, the ringer on/off switch and the volume up/down switch. The other phone and multimedia functions can be accessed using the touch screen.

For inputting text, the user can utilize the touch screen’s virtual keyboard. It has an automatic spell checker, a dynamic dictionary and predictive word capability. The predictive word function is integrated with the virtual keyboard so that the user does not have to be very accurate in typing. The keys are a bit bigger and spaced further apart if used in the landscape orientation. Although the texting feature of the iPhone has been considered its weakness, the virtual keyboard on the touch screen has been reviewed as a worthwhile risk.

For two weeks, New York Times’ David Pogue and The Wall Street Journal’s Walt Mossberg evaluated the iPhone and stated that learning how to use it was initially hard, although it got easier eventually. Pogue said that it was “frustrating” as they started using it, but “once you stop stressing about each individual letter and just plow ahead, speed and accuracy pick up considerably.” After using the iPhone for five days, Mossberg became adept in typing on it as he could using his Palm Treo and eventually deemed the keyboard as not that big an issue anymore. They both declared that the key to be able to successfully utilize the virtual keyboard was its typo-correcting function.

The interface of the iPhone allows the user to be able to reposition the content up or down through a finger’s touch-drag motion. Likewise, going through a menu’s lengthy list is easy as if the list was attached to a wheel’s external surface so that the wheel can be rotated through sliding a finger on the display which will allow the user to go through the list from top going down or bottom going up. Also, depending on the finger’s motion, the scrolling may be slower or faster, making the interface able to imitate the physics of three-dimensional objects.

Some examples demonstrating the multi-touch sensing capabilities of the iPhone are web page and photo album magnifications. This capability allows the zooming in and out of images or web pages through positioning two fingers on the touch screen and bringing them closer together or farther apart, much like squeezing or stretching the content.