Touch·screen – a display device that allows a user to interact with a computer by touching areas on the screen.
There are many touch screen technologies – around 18 different types of touch screens are present today in the market (According to the Geoff Walker of Walker Mobile ). some works with the infrared lights while other takes input from the sound waves. But out of those only two are most dominant which we all have just right in our hands – Our Phones . those two types are Resistive touch screen and Capacitive touch screen
1) Resistive touch screen – Before the launch of Apple’s debut iPhone, people use stylus for input or they need a thumb exercise to accomplish any task. Resistive screen need some pressure while clicking on an icon on screen , But why this is so?
Resistive screens are made up of two layers
a) Conductive Layer
b) Resistive Layer
While electric current keep running in conductive layer and when the screen is pressed resistive layer comes in contact with conductive layer and it detects the co-ordinates where screen is pressed and out the further process.
Pros :- Resistive screen are solid, durable and consistent.
Cons:- It Is harder to read on screen if you are out on a sunny day because as it consists of multiple layers which reflects the Ambient light. (Ambient light is the surrounding light reflected back from the screen and makes harder to see the text on the screen).
2) Capacitive touch screen – With the launch of Apple’s iphone, capacitive screens are introduced into the mobile market. Unlike resistive screens, capacitive screens doesn’t need any pressure of stylus or finger to operate the phone instead these screen can work with anything which holds the electric charge including human skin.
Capacitive screens are made using Indium Tin Oxide and Copper which store electric charge in a electro-static grid of tiny little wires each smaller than the human hair. Such type of screens are composed of 5 different parts.
a) A Glass Substance
b) Conductive Layer
c) Protective Layer
d) Controller and Electrodes
Glass substance consists of controller which keep the track of when and where the screen is touched But how happen?
The electrodes constantly apply a low voltage on conductive layer (a electro-static grid or field) and when we touch on the protective layer, a very minute electric charge is transferred from our finger and creates a voltage drop at that point of the screen, and this voltage drop is detected by the controller and the circuit is completed and appropriate action is taken according our touch.