Final Paper touch screen tech

8/12/2019 Final Paper touch screen tech

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TERM PAPER

On

(TOUCHSCREEN TECHNOLOGY)

Submitted to

AMITY SCHOOL OF ENGINEERING AND TECHNOLOGY

Guided By: DEEPAK GARG Submitted By: UTKARSH AGARWAL

Department: (APPLIED SCIENCE) Enrolment. No. :A2305212043

ASET Roll No : 043

B.tech in computer science (3 cse 1)

Amity University, Uttar Pradesh





CERTIFICATE

This is to certify that Mr UTKARSH AGARWAL , student of B.Tech. in Computer

Science & Engineer ing (Department) has carried out the work presented in the project

of the Term paper entitle " TOUCHSCREEN TECHNOLOGY" as a part of First

year programme of Bachelor of Technology in Computer science from Amity School of

Engineering and Technology, Amity University, Noida, Uttar Pradesh under my

supervision.

Name & signature

Deptt. Of Applied Sciences

ASET, Noida.



ACKNOWLEDGEMENT

It’s a great opportunity for me to write about subject like “touchscreen

technology". At the time of preparing this term paper I have gone through

different books websites which helped me to get acquainted with new topics.

I acknowledge with gratitude to my term paper guide SIR DEEPAK GARG, for

his immense help and guidance throughout the making of this term paper. He was

available whenever I needed him.

I would also like to extent my heartiest thanks to my parents for all the basic

support they provided me with. Especial thanks to my sister and my friends who

enable me to complete my work nicely. All praises are for Almighty God for giving

me healthy body, sound mind and nice surrounding.

Apart from me this term paper will help to those who are interested to know about

this subject. I hope they will find it comprehensible.

I have tried to gather all relevant documents regarding this topic. I don’t know

how far I am able to do that. Furthermore I don’t claim that all the information inthis term paper is included perfectly. There may be shortcomings, factual errors,

and mistaken opinion which are all mine and I alone am responsible for those but I

will try to give a better volume in future.

UTKARSH AGARWAL

(A2305212043)





“INDEX”

1.

ABSTRACT 2. INTRODUCTION

3. HISTORY

4. COMPONENTS OF TOUCH SCREEN TECHNOLOGY

5. TYPES OF TOUCH SCREEN TECHNOLOGY

6. RESISI TI VE TOUCHSCREEN (INC. PROS AND CON S.)

7. CAPACITI VE TOUCH SCREEN (INC. PROS AND CON S.)

8. SURFACE ACOUCTIC WAVE TOUCHSCREEN TECHNOLYGY

(INC. PROS AND CONS.)

9. I NFRARED TOUCH SCREEN TECHNOLGY (INC. PROS AND CON S.)

10. MUTLI TOUCH TECHNOLGY ( the plural technology)

11. THE FUTURE OF TOUCHSCREEN

TOUCHSCREEN CONSUMERS

12. REFERENCES



ABSTRACT

In today‘s society, the way in which we physically interact with electronic devices is

changing how we focus our technological research. This change has led to many great

advances, including the development of touch screen technology. Through the use of

touch screen technology, the operator is given an alternative method of how he or she

can interact with a device.

This technology operates in four distinct ways: Resistive systems, capacitive systems,

surface acoustic wave and infrared systems.

This paper will investigate, discuss, and compare these different technologies, focusing

on the differences in application, aspects of sustainability, as well as the positive and

negative qualities. In addition to which this paper will also include the components of

touch screen and the science behind it. This paper will also throw light on history of this

technology and the successful future of touch screen in coming years.

Throughout the past century, technology has improved in many ways. The way in which

humans interact with technology is one of the most important ways technology ischanging.

By using touch screen technology, the user is able to manipulate a digital environment

by only the touch of their finger, or another input device, on the screen. Throughout this

paper we will discuss the different technologies that make this possible: infrared,

surface acoustic wave , resistive and capacitive touch screens, as well as their qualities

in modern devices.



INTRODUCTION

Call it an effort of human mind or a miracle from human heart. But this is all happening

with technology. We land in an era where everything that can be possibly thought, can

also be practically put into. And that too quite reasonably..!!

Just move the hand or walk your fingers over a thing and it works. Yes, it is the

interactive gesture based technology (TOUCH SCREEN TECHNOLOGY) I am talking

about.

Touchscreen technology is the direct manipulation type gesture based technology.

Direct manipulation is the ability to manipulate digital world inside a screen without the

use of command-line-commands.

DEFINATION: A device which works on touchscreen technology is coined as

Touchscreen. A touchscreen is an electronic visual display capable of ‗detecting‘ and

effectively ‗locating‘ a touch over its display area. It is sensitive to the touch of a human

finger, hand, pointed finger nail and passive objects like stylus. Users can simply move

things on the screen scroll them, make them bigger and many more.

OBJECTIVE: This paper will investigate, discuss, and compare the different touch

screen technologies, focusing on the differences in application, aspects of

sustainability, as well as the positive and negative qualities.



HISTORY

The first ever touchscreen was developed by E.A Johnson at the Royal Radar

Establishment, Malvern, UK in the late 1960s. Evidently, the first touchscreen was a

capacitive type; the one widely used in smart phones nowadays.

In 1971, a milestone to touchscreen technology was developed by Doctor Sam Hurst,

an instructor at the University of Kentucky Research Foundation. It was a touch sensor

named ‗Elograph‘. With the invention of the Elograph, by Elographics, Inc [1]. This

company was created to ―produce Graphical Data Digitizers for use in research and

industrial applications‖ [1]. This technology set the stage for many devices to come.

Later in 1974, Hurst in association with his company Elographics came up with the

first real touchscreen featuring a transparent surface. In 1977, Elographics developed

and patented a resistive touchscreen technology, one of the most popular touchscreen

technologies in use today.

One of the next devices to be invented was the HP-150, the first touch screen computer.

Hewlett Packard invented this device in 1983 [2]. This technology is important because

it ―had inf rared touch-screen capability, allowing for creation of ATM-like

ap plications‖ [2]. These are two of the most important devices in the development of

touch screen technology

Ever since then, touchscreen displays are widely used in computers, user interactive

machines, public kiosks, point of sale applications, gaming consoles,

PDAs, smartphones, tablets, etc. As time progressed, touch screen devices have become

increasingly more complex and sustainable, providing the user with greater accuracy

and more features to improve the quality of life.



COMPONENTS OF TOUCH

SCREEN:

Three major components are:

Touch sensors

Controller

Software driver

A clear panel that has some method of sensing a touch event.

A controller which connects the touch sensor to the computer and translatesinformation from the sensor into a form the computer can understand.

A software driver which tells the computer how to interpret the touch eventinformation sent from the controller.

In standard touch screens, touching the screen is basically the same as left-clicking amouse. You can also tap the screen twice to double-click, and drag your finger acrossthe screen to perform drag-and-drop actions.



TYPES OF TOUCHSCREEN

TECHNOLOGY:

Let us now give an engineer‘s eye to this revolutionary technology. A touchscreen is a 2

dimensional sensing device made of 2 sheets of material separated by spacers.

There are several different touch screen technologies, each with their own advantages

and disadvantages

There are four main touchscreen technologies:

1) Resistive

2) Capacitive

3) Surface Acoustic Wave

4) Infrared



Resistive Touchscreen Technology:

Resistive touch screen systems are the most common type of touch screen technology in

today‘s market. These devices are used in many applications, such as cell phones,

handheld games, GPS navigation devices, and even some digital cameras [3].

The resistive touchscreen consists of a flexible top layer made of Polyethylene (PET)

and a rigid bottom layer made of glass. Both the layers are coated with a conducting

compound called Indium Tin Oxide (ITO) and then spaced with spacers.(3) While the

monitor is operational, an electric current flows between the two layers. When a touch is

made, the flexible screen presses down and touches the bottom layer. A change in

electrical current is hence detected and the coordinates of the point of touch is

calculated by the controller and parsed into readable signals for the operating system to

react accordingly.

Some of the popular devices that use Resistive Touchscreen are Nintendo DS, Nokia

N97, HTC Touch Pro2, HTC Tattoo, Sony Ericsson Satio, etc.

These systems transmit only 75% of light from the monitor. The resistive touchscreen is

further divided into 4-, 5-, 6-, 7- and 8-wired resistive touchscreen. While the

http://www.engineersgarage.com/articles/operating-systems-tutorial






constructive design of all these modules is similar there is a major distinction in each of

its method to determine the coordinates of touch.

The Four-wire Resistive Touchscreen uses both the layers to calculate the axes

information of the touch. Touch measurement in the 4-wire is a 2 step process.

The x-coordinate of the touch point is calculated by creating a voltage gradient

on the flexible layer, and the y-coordinate is determined by creating a voltage

gradient along the bottom layer.

Pros and Cons: Consequently, the 4-wire resistive touchscreen is less durable, feebly

accurate and can drift with environmental changes. However these negatives are

divulged only with large-sized touchscreen. These are relatively cheap, easily available

and consume low power.

The Eight-wire Resistive Touchscreen is simply a variation of the 4-wire one

with the addition of 4 sense wires, two for each layer. The sensing points aid in

reducing the environmental drift to increase the stability of the system. The 8-

wire systems are employed in sizes of 10.4‖ or larger where the drift can be

significant.

The Five-wire Resistive Touchscreen do not uses the coversheet (flexible

layer) in determining the touch coordinate. All the position sensing is employed

on the stable glass layer. In this design, one wire goes to the coversheet and four

wires are deployed to the four corners of the bottom sheet. The coversheet only

acts as a voltage measuring probe. The functioning of the touchscreen remains

unscathed even with changes in the uniformity of the conductive coating over

the coversheet.



Pros and Cons: Highly durable, accurate and reliable. This technology involves

complex electronics and is expensive. However, it can be used in sizes upto 22‖.

The Six and Seven wire resistive touchscreen is also a variant to the 5 and 4 wire

technology respectively. In the 6-wire resistive touchscreen an extra ground layer is

added behind the glass plate which is said to improve system‘s performance. While, the

seven – wire variant has two sense lines on the bottom plate. However, these

technologies are as prevalent as their counterparts.

The Resistive Touchscreen works well with almost any stylus-like object.



Capacitive Touchscreen Technology:

Capacitive touch screens are very important within the field of touch screen technology.

In the early 1990s, this technology made its initial appearance into the touch screen

market in laptop computers, as touch pads [3]. Recently, capacitive popularity has

grown, as it has become one of the leading technologies used in touch screen devices. In

2001, it began appearing in consumer devices, such as MP3-players and smart phones

[3]. This increase in attention is likely due to the effectiveness of its design, its use of

multitouch technology, and the popularity of Apple products using this technology:

iPod Touch, iPhone and most recently the iPad. [9]. The Capacitive Touchscreen

Technology is the most popular and durable touchscreen technology used all over the

world at most. It consists of a glass panel coated with a capacitive (conductive) material

Indium Tin Oxide (ITO). The capacitive systems transmit almost 90% of light from the

monitor.

The design of projected capacitive touch screens is somewhat similar to that of resistive

touch screens, in that they both utilize 2 layers of ITO, with perpendicular conductive

measuring strips on the ends of each layer [8], which are encased between two glass

layers (See Figure 4). This ―grid,‖ formed by the perpendicular conductive layers,

projects the electric field through the top layer of glass hence the name projected

capacitive touch screens [8]. Because of this projection, when the user touches the top

layer of glass it ―changes the measured capacitance values of the electrodes closest to it‖



[3]. This change in capacitance is due to the slight electromagnetic charge contained in

the human body [8]. These changes in capacitance are measured and calculated as touch

points in a very similar way to resistive touch screens, by using the X and Y

components.

Surface capacitive is another form of capacitive touch screen technology. The primary

difference between surface capacitive and projected capacitive is that surface capacitive

uses only one ITO surface [3]. This layer calculates touch points using principles that

are very similar to projected capacitive touch screens, in that touch points are observed

by changes in capacitance if the ITO layer in the touch screen. However, these touch

points are measured in a very different way. The computer measures the change in

capacitance from each corner of the ITO layer, and with these 4 separate measurements,

the X and Y coordinates of the touch point are calculated [3].

Pros and Cons: The surface capacitive touchscreen is moderately durable and needs

calibration during manufacture. Since a conductive material is required to operate this

screen, passive stylus cannot be used for surface capacitive touchscreen. In the

Projected-Capacitive Touchscreen Technology, the conductive ITO layer is etched to

form a grid of multiple horizontal and vertical electrodes. It involves sensing along both

the X and Y axis using clearly etched ITO pattern. The projective screen contains asensor at every intersection of the row and column, thereby increasing the accuracy of



the system. There are two types of projected capacitive touchscreen: Mutual

Capacitance and Self Capacitance.



Surface Acoustic Wave Touchscreen

technology:

The Surface Acoustic Wave Touchscreen technology contains two transducers

(transmitting and receiving) placed along the X-axis and Y-axis of the monitor‘s glass

plate along with some reflectors. The waves propagate across the glass and are reflected

back to the sensors. When the screen is touched, the waves are absorbed and a touch is

detected at that point. These reflectors reflect all electrical signals sent from one

transducer to another. This technology provides excellent throughput and image clarity.

Pros and Cons: 100% clarity is obtained as no metallic layers are present on the screen,

it can be operated using passive devices like stylus, glove or finger nail. Screen can get

contaminated with much exposure to dirt, oil which may haunt its smooth functioning.



INFRARED TOUCH SCREENS:

There are two main infrared systems: a standard grid and an internal reflection system.

These systems are very accurate; however, they require more space than other touch

screen systems. Dr. Andrew Hsu, an expert on touch screen technologies, states that ―IR

(infrared) screens are among the most durable surfaces and can handle hostile

environments, making them well suited for military applications‖[3].Although we will

not be focusing on the technology in terms of military applications, we can see that

infrared touch screen technologies, while being the most durable surfaces,are also quite

possibly the most versatile. This versatility comes from having two variant systems of

infrared touch screen. The first system is similar to resistive systems, which will be

discussed later, in that it consists of a two dimensional grid of infrared light. In this

technology, infrared LEDs (light emitting diodes) are arranged on opposite sides of the

unit underneath the glass. The diodes project infrared light into sensors located directly

across from them. The sensors read the strength of the beams, and ―when a user makes

contact with the screen, the system measures the drop in the sensoroutput signal; this

measurement allows the system to compute the location of the touch‖ [3]. This is to say

that when the finger touches the screen, the infrared beams are obstructed by the user‘sfinger; however, some light continues to pass to the sensor. The sensors send the

measurements of light to the operating system, which analyzes the data and recognizes

where the user touched. This technology has multi-touch capability because the beams

of light are never fully obstructed by the user‘s touch.

The second type of infrared system requires more space than the first. This system is

based upon internal reflection; a beam of light is emitted from within the unit, hits the

glass, and part of the beam exits through the lens while the other part goes back into the

unit. Cameras are placed inside the unit and are calibrated to the standard reflection to

the beams so that, ―when objects such as fingers touch the surface, the light diffuses at

the contact point, causing the acrylic‘s internal-reflection pathways to change. A camera

below the surface captures the diffusion and sends the information to image-processing

software, which can read multiple touches simultaneously and translate them into a

command‖ [4].



In the example stated, the screen is an acrylic screen rather than standard glass,

allowing for a thinner lens that is just as durable, cheaper, and more resilient. Advances

are being made in internal reflection systems to make the instruments much smaller.

One of these advancements, called Thin Sight, is ―a thin form-factor interactive surface

technology based on optical sensors embedded inside a regular liquid crystal display‖

[5]. ThinSight will allow a row of circuitry that possesses hundreds of small infrared

LEDs, similar to the emitters and sensors, used in standard infrared systems. These

sensors and emitters are much smaller and would cover a much smaller area of the

screen. Traditional internal reflection system only required four or five emitters and

cameras. Thinsight technology is still in development; however, it is believed that these

advancements could make infrared touch screen technology much smaller. The

advancements would also cause the system to be more available for future consumer

touch screen devices.

Microsoft Surface As mentioned above, the Microsoft Surface is a great example of

internal reflection infrared touch screens. In early 2001, ―Steve Bathiche of Microsoft

Hardware and Andy Wilson of Microsoft Research began brainstorming concepts for an

interactive table‖, beginning the development of the Surface [6]. The process continued

indevelopment until 2003 when the idea was presented to Bill Gates, and 85 prototypes

were created for developers on the Surface Computing group, a group created in 2004 to

solely develop the Surface. In 2005, various prototypes were created and analysed , and

eventually, in 2008, the Microsoft Surface was on sale to the public for $12,500 or

$15,000 [6].The Surface‘s ―technology uses multiple image sensors around one side of

the touch surface and IR backlights on the other side. When a user places his finger on

the surface, intercepting the infrared beam, the device projects a shadow. Using multiple

cameras, the unit converts this shadow into a touch point through triangulation‖ [3]. As





systems are large systems because of the space required for cameras to accurately

measure the shadow produced by the infrared LEDs. The large space required for larger

instruments does make internal reflection devices the most accurate touch screen

technology.

. Infrared touch screens are by far the biggest of the touch screen technologies. They are

also more expensive than resistive and capacitive touch.



MULTI -TOUCH TECHNOLOGY

(The Plural Touch Technology..! )An important feature of capacitive touch screens is their ability to recognize and

calculate multiple touch points at one time, commonly called multi-touch. ―Multi- touch

technology has been around since early research at the University of Toronto in 1982‖

[4]. The uses of this technology are very vast, allowing for greater human computer

interaction. This technology is traditionally associated with capacitive touch screens,

but is not limited to this technology. It can also be found in infrared touch screens and is beginning to appear in resistive touch screens [3]. Currently, multi-touch technology is

being used with a purpose similar to the function keys (Control, Alt, Option, Command,

etc.) on a standard keyboard. By adopting these functions, the user is able to complete

the same tasks as before, but with one hand. With advances in hardware, multi touch

will allow multiple users to access the same device simultaneously, like the Microsoft

Surface‘s capability of 300 plus touches. While the hardware is available to create such

devices, software implementation is holding back the growth of multi touch.

The latest multitouch technology in the market:

Apple iPhone: ‗Multitouch‘ now is a trademark by Apple who rightly proved it with a

bang with the first most successful multitouch device ever; the iPhone. The first iPhone

was unveiled on January 9, 2007. iPhone is no less than a revolution in the touchscreen

industry with its maestro functionalities and applications. It uses Mutual Capacitance

Technology as its touchscreen. The capacitive touchscreen can only be operated by bare

finger or multiple fingers for multi touch.

Microsoft Surface: is a multi touch product from Microsoft that allows multiple users

to manipulate digital content through surface computing. The main feature of this

product is its Surface‘s interface: Direct interaction, multi-touch contact, object

recognition and multi-user experience. It is not based on and limited by the

conventional touch technology. The surface utilizes Frustrated Total Internal Reflection

and underneath projectors for its display operation. It is indeed a milestone in the multi-touch scenario.



THE FUTURE OF TOUCH

For now, the latest developments in touch screen technology include what is considered

as an interactive touch screen — it is perceived that the screen shapes itself allowing a

user to click a button. A. Peshkin and J. Edward Colgate, professors at Northwestern

University, are at the forefront of this innovation. The Tactile Pattern Display, TPaD,

has a small devise, piezoelectric ceramic disc that vibrates the outer most layer of glass.

The vibrations through the glass create a small layer of air between the user‘s finger and

the screen itself. This changes the coefficient of friction between the finger and screen

making it appear that the glass itself has changed. Peshkin and Colgate explain that,

―the entire plate vibrates, so the amount of friction is the same all over the TPaD‘s

surface at any given time. But because the oscillations are modulated as your finger‘s

position changes, the device fools you into thinking that there are varying amounts of

friction at different locations. The prototype uses optical sensors to keep track of your

finger‘s position. The friction reduction can be switched on and off so quickly (within

about 4 milliseconds on average) that the pitch of virtual bumps or dips can be made far

finer than what a fingertip can discern‖ [14].The TPaD is still in the prototype phase of

development; however, it is a step forward with human interaction with technology.How far and how fast touchscreen technology develops is only limited to the funding

and resources available. Expect to be interacting with your devices more and more as

advances are made in technology.

TOUCH SCREENS AND CONSUMERS

Moving towards the future, consumers will continue to see the growth of the touchscreen industry, due to extensive engineering advancements in user interfaces. The

ability to physically touch a screen is easier than searching for a specific key in a sea of

buttons. Society, for these reasons, has found touch screens to be the future of many

devices. The social norm of today includes walking down the street surfing the web on

an iPhone or sifting through music on an iPod Touch. No additional buttons are

necessary, just the small, portable device in one‘s pocket until needed. Society will

continue to see the development of touch screen technology as human-device

interaction is perfected.



REFERENCES:-

[1]―Company history from Elographics to Elo TouchSystems, 1971 -present - Elo

TouchSystems - Tyco Electronics‖. www.elotouch.com.

http://www.elotouch.com/AboutElo/History/default.asp. Accessed 3 March 2010.

[2]―The HP150‖.www.columbia.edu.http://www.columbia.edu/acis/history/hp150.html.

Accessed 3 March 2010.

[3]Hsu, Andrew. "Choosing a touch technology for handheld-system applications."

EDN, January 8, 2009: 40-44.

[4]Nichols, Steven J. Vaughan ―New Interfaces at the Touch of a Fingertip‖IEEE

Society August. 2007: 12-15.

[5]Izadi, Shahram, et al. "ThinSight: A Thin Form-Factor Interactive Surface

Technology." Association for Computing Machinery.

[6]"The Origins of Microsoft Surface". www.microsoft.com.

http://www.microsoft.com/surface/Pages/Product/Origins.aspx. Accessed 3 March

2010.

[7]"The Microsoft Surface Vision System". www.microsoft.com.

http://go.microsoft.com/?linkid=9707395. Accessed 3 March 2010.

[8] Gray, Tony. ―Projected Capacitive Touch Screen Technology‖. Ocular, Inc.

Accessed 3 March 2010.

[9] ―Apple.com‖. www.Apple.com. http://www.apple.com. Accessed 3 March 2010.

[10] Walker, Geoff. ―The Apple iPhone‘s Impact on the Touch-Panel Industry‖.

Information Display 5/07. Accessed 3 March 2010.

[11]"Apple Reinvents the Phone with iPhone". www.Apple.com.

http://www.apple.com/pr/library/2007/01/09iphone.html. Accessed 3 March 2010.

[12] Walker, Geoff. ―Touch and the Apple iPhone‖. Veritas et Visus. Accessed 3 March

2010.



[13]"Apple Launches iPad". www.Apple.com.

http://www.apple.com/pr/library/2010/01/27ipad.html. Accessed 3 March 2010.

[14]Jones, Willie D. ―Touch Screens with Feeling‖ IEEE Spectrum May. 2009: 15.

Accessed 3 March 2010

[15] www.google.com, yahoo.com.

[16] Wikipedia

[17] www.engineersgarage.com



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Final Paper touch screen tech