With the proliferation of the Internet, today's mobile devices can display a wealth of interactive Web content. The touch screen provides a particularly efficient user interface for mobile devices because it does not require any peripheral user interface components, like a keyboard, mouse, or track pad. All that is needed to interact with the touch screen's user interface is a finger or a stylus. But as devices shrink in size, the human finger is not always an ideal pointer.
Touch screens may be implemented in a device by overlaying a capacitive touch-sensitive pad over a surface of a display screen. The display screen displays information to a user, and the touch-sensitive pad receives input by detecting the user touching the touch-sensitive pad. Capacitive touch-sensitive pads generally comprise sensors that detect a user's touch by sensing a capacitance between the user's finger and one or more of the touch sensors. The touch (i.e., capacitance) detected by the touch-sensitive pad is received as a user input that is interpreted by the device in accordance with several variables and/or conditions relating to the user's touch. Some of these variables and conditions may include the content displayed on the screen, the status of the device, the location of the touch, the duration of the touch, and combinations thereof.
A human finger is generally much larger than the point of a stylus, and therefore the two create different capacitive effects on a capacitive touch screen. Today's devices commonly allow either a finger or stylus to be used, so they must be able to recognize either's electrical charge displacement. Some users prefer to use a stylus because it is smaller and provides greater precision for interacting with the touch screen. User preferences drive sales of mobile devices, so a device's inability to properly recognize stylus touches can quickly scare away customers.