The development of iphone touch screen digitizer
The technology principle of resistive touch screen digitizer:
Along with the maturity of technology, the touch screen digitizer is more and more used for cellphones and its identity also changes from high senior goods to the essential technology that can be used by universal people. Now the mobile phone based on touch screen digitizer almost has dominated nearly half of market proportion in the mobile phone market. But touch screen digitizer was embodied mainly as handwritten function for a long time in the past, so we often said touch screen mobile phone for handwritten phone. But since the appearance of apple iPhone, the traditional concepts seems to be broken and the application of iphone touch screen digitizer was suddenly pulled to a whole new field. At that time, we can know the touch-screen digitizer can completely change our operation to equipment in addition to handwriting.
Below we will learn about the technology principle of touch screen digitizer firstly. In the past we have contacted with the touch screen mobile phones. For example, the MOTOROLA A6188 or DuoPuDa PPC mobile phones, both of which are using the technology called "resistive touch screens". This screen is constituted of two layers coated with transparent conductive material such as glass and plastic.When the user touch the screen, the conductance layer within two layers will joint, and the voltage of current position will be made for change. So that the position of touch points can be acquired.
More advanced capacitive touch screen digitizer:
The technology of capacitive touch screen digitizer which is used by new and high-end touch screen mobile phones such as iPhone and Prada works with the current induction of human body. The apacitive touch screen digitizer is a 4 layer compound vitreous screen, and both of the inner surface of the glass screen and sandwich have been coated with ITO (coating conductive glass).The outermost is a thin protective layer of silicon soil glass and the ITO is treated as working surface. From four angles, four electrode is derivated.The inner ITO is used for shield in order to ensure good working environment. When you use the touch screen, the current will outflow from the electrode of its four corners and the current flowing through the four electrode is proportional to the distance from finger to the four corners. The controller can get the information of touch points based on the precise calculation to the four current proportion.
The capacitive touch screen iphone digitizer can be identified by system when the user touched gently, while our common resistive touch screen digitizer can be percepted by system only after the user "push" down. This is also the key point of iphone success using virtual screen keyboard.