Touch screens are something used in everyday life. But what are the different types of touch screen technology, how do they work, when were they developed?
These are some types of Touchscreens: Resistive Touch Screens: Resistive touchscreens are composed of two electrically conductive layers of thin metal film separated by a tiny air gap. When pressure is applied to the surface of the touchscreen, the two sheets are pressed together, and a circuit is completed. The advantages of resistive touchscreens are that they are relatively cheap to produce and are cost efficient to use. The disadvantages of resistive touchscreens are a lack of input precision when used with larger screens and lack of overall screen clarity.
Capacitive Touch Touchscreens: Capacitive touchscreens are coated with a transparent conductive film. When a fingertip comes into contact with a capacitive touchscreen, it can use the conductivity of the human body as a means for input. Electrostatic capacitive touchscreens are used in numerous smartphones such as Apple iPads and iPhones. The disadvantages of capacitive touchscreens are they only react to a conductive material, and they may not work correctly if wet.
Surface Acoustic Wave Touch Screens: Ultrasound surface wave acoustic touch screens operate by tracking ultrasonic sound waves to identify the location of points on a screen. Surface wave acoustic touch screens are made with a single pane of glass, a transmitter, and two piezoelectric receivers. The transmitter produces ultrasonic waves that move over the screen, reflect and then are read by the receiving piezoelectric receivers. When the surface of the glass is touched, some acoustic waves are absorbed, but some bounce back and are detected by the piezoelectric receivers. Because ultrasound surface wave acoustic touch screens use glass, they have high transmittance and long operating lives.
Optical Touchscreen technology: Optical touch screens use infrared emitters combined with infrared image sensors to continuously scan the touchscreen. When an object comes into contact with the touchscreen, it blocks some of the infrared light being received by the sensors. The location of the contact is then calculated by using information from both sensors and mathematical triangulation. Much like ultrasound surface wave acoustic touchscreens, optical touch screens have high transmittance and because they use infrared sensors, can be operated by both conductive and non-conductive materials. Optical touchscreens support multi-touch events and gestures calculated by algorithms. The size of optical touch screens is easy to scale, thereby making them well-suited for TV news and other television broadcasts.
Electromagnetic Guidance Technology: An electromagnetic guidance touchscreen sends out an electrical charge that reacts with a stylus. The stylus then sends out a signal that allows the touchscreen to precisely identify its position. The placement of an electromagnetic induction sensor under a liquid crystal screen makes performing highly detailed operations possible, unlike a capacitive touchscreen. One disadvantage of electromagnetic guidance touchscreens is they require a designated stylus.
The idea of a touch screen was first described and published by E.A. Johnson in 1965. In the early 1970s, the first touch screen was developed by CERN engineers Frank Beck and Bent Stumpe. The physical product was first created and utilized in 1973. The first resistive touch screen was developed by George Samuel Hurst in 1975 but wasn’t produced and used until 1982.