The iPhone 1 or the initial iPhone was the first of the generation of smartphones. What differentiated it from conventional phones was its design. Its screen was the phone, unlike other phones where the keypad consumed majority of the space on the phone. What enabled this transition was the development of the touch screen. This feature gained popularity rapidly and was loved by users as it was easy to handle and was highly convenient. The touch screen defines the iPhone and is an integral feature of it.
In this article, I will be explaining the working of the touch screen. There are various methods used by different devices to detect input on the touch screen. Majority of touch screens make use of circuitry and sensors in order to monitor changes to the screen for this purpose. The iPhone monitors changes in the form of electrical current. Other ways to detect changes is by using reflection of waves, both sound waves and light waves, transducers to detect vibrations or cameras.
The basic working is quite simple. When a finger is placed by someone on the screen, the state being monitored by the device changes. In the case of the iPhone 1, which uses electrical signals, a capacitive material layer is used to hold electrical charges. When one touches the screen, the amount of charge at the point of contact is changed. This change is detected by the device as its input.
General touch screens detect the location of one touch only. The result of touching the screen in many places can be quite erratic. This is different for the iPhone 1. The interface is developed for multiple touches as a number of elements need touching at more than one point at the same time. One example would be zooming in to images. This is done by placing two fingers on the screen and spreading the two fingers apart. Zooming out requires pinching in of two fingers at the same time. This touch screen is capable of responding to signals at both points of contact and their movements together at the same point of time.
This multi- touch screen is a unique feature. The capacitors of the screen are arranged as per a coordinate system. The circuit is capable of detecting changes at every point on the grid. Every point has its own relay sensors and input. This is what makes it possible to responds to touches at two different points at the same time. Due to the reliance of the screen on the capacitive material, the iPhone 1 responds to touch only from a finger.
The detection of touch occurs by two methods. The first method, mutual capacitance, consists of two layers of capacitive material. The first layer has diving lines to carry current while the second has sensing lines to detect the current. The second method is self capacitance in which there is a layer of single electrodes that are connected to the rest of the sensing circuitry of the capacitive material. Learn more about the iPhone 2 disassembling, iPhone 3 specifications, iPhone 4 unlock and iPhone 5 iCloud