TOUCHSCREEN TECHNOLOGY

OVERVIEW Comparison of touch screens Introduction Technologies Advantages & Disadvantages Applications Future Touchscreen technology Conclusion

INTRODUCTION A touchscreen is a display that can detect the presence and location of a touch within the display area. The term generally refers to touch or contact to the display of the device by a finger or hand. Touchscreen can also sense other passive objects, such as a stylus.

History Touchscreens emerged from academic and corporate research labs in the second half of the 1960s. One of the first places where they gained some visibility was in the terminal of a computer-assisted learning terminal that came out in 1972 as part of the PLATO project. The HP-150 from 1983 was probably the world's earliest commercial touchscreen computer. It doesn't actually have a touchscreen in the strict sense, but a 9" Sony CRT surrounded by infrared transmitters and receivers which detect the position of any non-transparent object on the screen.

Development The development of multipoint touchscreen facilitated the tracking of more than one finger on the screen, thus operations that require more than one finger are possible. These devices also allow multiple users to interact with the touchscreen simultaneously. With the influence of the multi-touch-enabled iPhone and the Nintendo DS, the touchscreen market for mobile devices produced 5 billion in 2009.

Touch screen technology Main touch screen components: 1 Touch sensor 2 Controller 3 Software driver

TOUCH SENSOR. A touch sensor is a clear glass panel with a touch responsive surface . The sensor generally has an electrical signal going through it and touching the screen causing a signal change. The signal change is used to determine the location of the touch to the screen.

CONTROLLER The controller is small PC card that connects between the touch sensor and PC. It takes information from the touch sensor and translate in to information that PC can understand.

SOFTWARE DRIVER The driver is a software that allows the touch screen and computer to work together. It tells the operating system how to interpret the touch event information that sent from the controller. Most of the touch screen drivers today are mouse emulation type driver .

Construction There are several principal ways to build a touchscreen: In the most popular techniques, the capacitive or resistive approach, manufactures coat the screen with a thin, transparent metallic layer. When a user touches the surface, the system records the change in the electrical current that flows through the display. Dispersive-signal technology which 3M created in 2002, measures the piezoelectric effect — the voltage generated when mechanical force is applied to a material — that occurs chemically when a strengthened glass substrate is touched.

TYPES OF TOUCHSCREEN Resistive Touch screen Capacitive Touch screen Infrared Touch screen

Technologies The types of technologies that can be found are as follows: Resistive: The resistive touch screen uses a glass panel with a uniform conductive ITO(Indium Tin Oxide) coating on the side surface. A PET film is a tightly suspended over the ITO coating surface of a glass panel.

Working Principle: When the screen is touched, it pushes the conductive ITO coating on the PET film. That results the electrical contact, producing the voltages. It presents the position touched. Resistive touchscreen deliver cost-effective, consistent and durable performance

Capacitive: Capacitive touchscreen is a four multi-layer glass. Small amount of voltage is applied to the electrodes on the four corners A human body is an electric conductor, so when touched the screen with a finger, a slight amount of current is drawn, creating a voltage drop. The current respectively drifts to the electrodes on the four corners. The capacitive system has very long life (about 225 million clicks).

Infrared: Conventional optical-touch systems use an array of infrared (IR) light-emitting diodes (LEDs) on two adjacent bezel edges of a display, with photosensors placed on the two opposite bezel edges to analyze the system and determine a touch event. IR eliminates the use of glass or plastic overlay that most other touch technologies require in front of the display. High cost of the technology. IR increases the noise floor at the optical sensor

Advantages & Disadvantages: User friendly. Fast response. Error free input. Easy to install. Use finger, fingernail, gloved hand, stylus or any soft-tip pointer to operate. Easy to clean and maintain. Compatible with Windows, Macintosh and Linux. Does not interfere mouse and keyboard function. Make computing easy, powerful and fun.

Disadvantages: 1)Finger stress: Stress on human fingers when used for more than a few minutes at a time. (for example, ATMs). 2)Fingerprints: Touchscreens can suffer from the problem of fingerprints on the display. 3)User has to sit closer to the screen as compared to external keyboard. 4) The screen may be covered more by using hand.

Applications Public Access:  Museums  Library resource guides  Corporate information  Public Transportation Schedule / Status Airport terminal passenger internet and email systems Automated travel and entertainment ticket dispensers Shopping mall directory

Conclusion: Designers are trying to use touchscreen to simplify input commands for largely unsophisticated computer users. Today, a larger share of population is PC literate, yet the touchscreen has become adopted by computer users of all abilities because it is simple, fast, and innovative. In future there is no usage of mouse and keyboards as they will be replaced by touchscreens.

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