Context: Recently, Volkswagen brought back physical buttons after complaints about its touchscreen. 

About Touchscreen

• Touchscreen is an electronic visual display capable of ‘detecting’ and ‘locating’ a touch over its display area. 
• It combines two functions i.e. to receive inputs for a computer and to display the output. 
• Examples: Smartphones, ATM machines, various household appliances (including TVs and refrigerators), e-readers, billing systems, and electronic voting machines.

Types of Touchscreens

• The two most common types of touchscreens are capacitive and resistive which are based on the phenomenon of conduction and resistance respectively. 
• Other touchscreen technologies are based on optical inputs and acoustic waves. 

About the Projected Capacitive Method

• Composition: There are two conducting layers and each layer consists of strips of conducting material.
  • In one, the strips run left to right, and in the other from top to bottom. 
• Working: When two strips cross over each other, they form a capacitor, and is used to measure where a finger has touched the screen. 
  • It is significant in detecting multiple simultaneous touches.
• Use: It is used in smartphones with the mutual capacitance architecture.

About Resistive Touchscreens

• About: It uses the property of resistance. Resistance is a measure of the opposition to current flow in an electrical circuit.
• Composition:  There are two sheets, both are conductors which are separated by a small gap. 
• Working: 
• • Flow of Current using Sensation Mechanism: When a finger touches one sheet, it moves it at that point to touch the underlying sheet and allows a current to pass. 
  • Sensing by the Sensors: Sensors use this flow of current and with the help of processor, determine the point of touch. 
• Significance: Resistive touchscreens are cheaper to make and require less power to operate. 
• Concern: It emits less light and its appearance is bulky.                                 

Also Read: On Smartphone Manufacturing In India

News Source: The Hindu