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.
Invention Journey
- 1965: The touchscreen was invented by E.A. Johnson to overcome the limitations in man-machine communications.
- 1970: G. Samuel Hurst invented the resistive touchscreen.
- 1982: Nimish Mehta developed a touchscreen that could sense two touches at the same time.
- 1983: Myron Krueger reported a way to capture different hand gestures as actions on a screen.
- 1984: Bob Boie developed the first transparent (capacitive) multitouch interface.
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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:
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- 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
December 20, 2023