The Multi-Touch display that is being used in iPhone is not new in the gadgets universe, but certainly it represents the first mass production effort. Initial reviews by only handful of people who had access to the phone were very positive and many commented on the ease of navigation even when accessing the most complicated screens.

Let’s take a closer look at the technology behind this revolutionary invention. The Multi-Touch display was initially called a Multipoint display by Apple engineers. The most prominent engineers who worked on the iPhone were Steve Hotelling, Joshua Strickon and Brian Huppi. Their names are listed on the Patent application, called “Multipoint touchscreen” with a Serial Number of 840862.

The surface of the Multi-Touch display is covered with a transparent electrode layer that is composed of indium tin oxide [which is in chemistry terms is a mixture of 90% of indium oxide (In2O3) and 10% of tin oxide (SnO2)]. The surface is yellowish to grey in color but possesses transparent qualities. The main features of this design are electrical conductivity and optical transparency – which were the main two criteria for selecting this material by Apple’s engineers.

However, the optimal solution for the multi-touch display comes with some limitations. First of all, a limited supply of indium on the world markets and high demand make the iPhone screen expensive and difficult to manufacture. Secondly, the layers of the Multi-Touch display are very fragile and lack flexibility, making replacement a possibility.

However, the most important part of the screen is not the actual material it’s made out of, but rather the disposition of the sensitive material on the screen. According to Apple’s patent application, the “touch screen includes a multipoint sensing arrangement configured to simultaneously detect and monitor touches and the magnitude of those touches at distinct points across the touch sensitive surface of the touch screen.”

The important part of this is that the screen is not only capable of sensing distinct points but also sensing the magnitude of the touch. This additional functionality comes in handy when navigating speed is desired. For example; if a touch is strong then pages can be flipped more quickly. It’s important to note that there are two different layers on the screen: “driving lines are formed on a first layer and sensing lines are formed on a second layer,” according to the patent information.

As a result of this heavy investment into new technology the Apple iPhone is able to fully support QWERTY keyboard functions. SMS messages can be sent in multiple user sessions. The iPhone is a Smart Phone, so it uses predictive keyboard functionality, which helps to prevent and correct mistakes as the user types.