TOUCH SCREEN TECHNOLOGY

A TECHNICAL SEMINARPRESENTED BY

M.V.S.S.PRADEEP(07A91A0543)

CONTENTS1. Introduction2. History3. Technologies4. Construction5. Development6. Ergonomics and usage7. Comparison of touch screen technologies8. Screen protectors9. Conclusion

1.Introduction A touch screen is an electronic visual display that can detect the presence and location of a touch within the display area.

The term generally refers to touching the display of the device with a finger or hand. Touch screens can also sense other passive objects, such as a stylus.

2.History In 1971, the first "Touch Sensor" was developed by Doctor Sam Hurst while he was an instructor at the University of Kentucky.

In 1974, the first true touch screen incorporating a transparent surface was developed by Sam Hurst and Elographics.

In 1977, Elographics developed and patented five-wire resistive technology, the most popular touch screen technology in use today.

The HP-150 from 1983 was one of the world's earliest commercial touch screen computer.

Until recently, most consumer touch screens could only sense one point of contact at a time, and few have had the capability to sense how hard one is touching.

Historically, the touch screen sensor and its accompanying controller-based firmware have been made available by a wide array of after-market system integrators, and not by display, chip, or motherboard manufacturers.

3.Technologies

There are a variety of Touch-screen technologies. Some of them are,

1. Resistive2. Surface acoustic wave3. Capacitive4. Infrared5. Optical Imaging6. Dispersive signal Technology7. Acoustic pulse recognition

Resistive touch screen

Infrared touch screen

4.ConstructionThere are several principal ways to build a touch screen. there are typically four layers,

1. Top polyester layer coated with a transparent metallic conductive coating on the bottom

2. Adhesive spacer3. Glass layer coated with a transparent metallic

conductive coating on the top4. Adhesive layer on the backside of the glass for

mounting.

5.Development Virtually all of the significant touch screen technology patents were filed during the 1970s and 1980s and have expired.

The development of multipoint touch screens facilitated the tracking of more than one finger on the screen.

With the growing acceptance of many kinds of products with an integral touch screen interface, the marginal cost of touch screen technology is routinely absorbed into the products that incorporate it and is effectively eliminated.

6.Ergonomics and UsageThe different ergonomics due to usage of touch screens are,

1. Finger stress2. Finger nail as stylus3. Finger prints4. Combined with hap tics5. Gorilla arm

7.Comparision of touch screen technologies

We can compare different touch screen technologies based on the following factors,1. Durability2. Stability3. Transparency4. Response time5. Touch6. Intense light resistant7. Monitor option8. Water proof

Technology 4-Wire Resistive Surface Acoustic Wave 5-Wire Resistive Infrared Capacitive

Durability 3 year 5 Year 5 Year 5 Year 2 Year

Stability High Higher High High Ok

Transparency Bad Good Bad Good Ok

Installation Built-in/Onwall Built-in/Onwall Built-in/Onwall Onwall Built-in

Touch Anything Finger/Pen Anything Finger/Pen Conductive

Intense light-resistant Good Good Good Bad Bad

Response time <10ms 10ms <15ms <20ms <15ms

Following Speed Good Low Good Good Good

Excursion No Small Big Big Big

Monitor option CRT or LCD CRT or LCD CRT or LCD CRT or LCD CRT or LCD or LED

Waterproof Good Ok Good Ok Good

8.Screen protectors

Its very important to take protection on screens while using touch screens.

Some touch screens, primarily those employed in smart phones, use transparent plastic protectors to prevent any scratches that might be caused by day to day use from becoming permanent.

9.Conclusion This paper presents the importance, history, different technologies and different aspects in using the touch screens.

Although touch screens provide a natural interface for computer novices, they are unsatisfactory for most applications because the finger is such a relatively large object.

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