Touchscreen Technology Anandu Narayanan S3 EC

What is a Touchscreen ? It is a display which responds to human touch It acts as both input and output device

Components of a touchscreen 1.Touch Sensor 2.Controller 3.Driver

History and Development E.A Johnson invented touchscreen in 1965 at The Royal Radar Establishment. Multi-touch was developed in 1982. Gestures were developed during the 1990s. First touchscreen phone IBM Simon was released in 1993.

Resistive Touch Screen Advantages Low cost of production High resistance to dust and water Best suited for handwriting recognition Disadvantages Poor sensitivity Doesn’t support multi-touch

Capacitive Touchscreen Locates touch position based on variation in capacitance Wide application in consumer electronics Highly sensitive Supports multi-touch and gestures

Infrared grid touchscreen Poor multi-touch accuracy Slow response time Hovering over screen can result in false responses

Surface Acoustic Wave Works on the principle that human body absorbs ultrasonic waves Immune to electromagnetic interferences Easily disturbed by foreign particles

Optical Touchscreen CMOS infrared cameras monitor the entire field of view The touch location is triangulated based on information from the cameras

Dispersive Signal Technology DST responds to touch by analysing the mechanical waves produced due to touch. Piezoelectric sensors placed at the four corners of the screen accurately locates the touch location.

Applications Capacitive touchscreens are extensively used in the smartphone industry DST is used in large touch screens which are generally greater than 32 inch Used in kiosks and for interactive navigation Used to implement digital variant of many acoustic musical instruments

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