final touch screen sensor

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Touch screen Technology

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Group Members61 Vipul T.

62 Rameshwar S.

63 Ekathrine

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656667 Habib68 Aditya P.

69 Hanif70 Nitin J.

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Introduction:

In 1971, the first "touch sensor" wasdeveloped by Doctor Sam Hurst (founder of

Elographics)

In 1977, Elographics developed andpatented five-wire resistive technology, themost popular touch screen technology in usetoday.

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A touch screen is a display that can detect thepresence and location of a touch within thedisplay area, generally refers to touch orcontact to the display of the device by a

finger or hand. Touch screen is also an inputdevice. The screens are sensitive to pressure;a user interacts with the computer by touchingpictures or words on the screen,Touchscreenscan also sense other passive objects, such as astylus

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How Does a Touch screen Work?

A basic touch screen has three main components:

1 Touch sensor

A touch screen sensor is a clear glass panel with a touchresponsive surface. The touch sensor/panel is placed over adisplay screen so that the responsive area of the panelcovers the viewable area of the video screen.

2 Controller

The controller connects between the touch sensor and thePC. It takes information from the touch sensor and translatesit into information that PC can understand. The controllerdetermines what type of interface/connection you will needon the PC.

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.

3 Softwaredrive

The driver allows the touch screen and computer to worktogether. It tells the computer's operating system how to interpretthe touch event information that is sent from the controller

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Touchscreen Technology Resistive touchscreen

Capacitive touchscreen

Infrared touchscreen Surface acoustic wave (SAW) touchscreen

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Resistive touchscreen

Structure

Resistive touch screensconsist of a glass or acrylic

panel that is coated withelectrically conductive andresistive layers made withindium tin oxide

(ITO) .The thin layers areseparated by invisiblespacers.

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Resistive touchscreen Characteristics:

1. Cost effective solutions

2. Activated by a stylus, a finger or gloved hand

3. Not affected by dirt, dust, water, or light4. 75%~85% clarify

5. resistive layers can be damaged by a very sharp object

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Capacitive touch screen

StructureCapacitive touch screens have front and

back protective glassproviding optical and strengthenhancement options.

Its middle layer consists of a laminatedsensor grid of micro-fine wires, and

optical enhancement options.

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Capacitive touchscreen During a touch, capacitance forms between the finger and the

sensor grid. The embedded serial controller in the touchscreen calculates touch location coordinates and transmits

them to the computer for processing.

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Capacitive touchscreen Characteristics:

1. Durable and resistant to scratches for demanding applications

2. Faster and more responsive

3. Immune to surface contaminants

4. Superior optical clarity, brighter display and less surface reflection

5. Must be touched by finger, will not work with any non-conductive

input

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Infrared touchscreen

Infrared (IR) technology relies on the interruption of an IR

light grid in front of the display screen.

The IR controller sequentially pulses the LEDs to create a grid

of IR light beams.

When a stylus, such as a finger, enters the grid, it obstructs the

beams.

One or more photo transistors from each axis detect the

absence of light and transmit signals that identifies the x and y

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Infrared touchscreen

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Infrared touchscreen Characters:

1. Clear as glass, improves reading ability

2. Most durable surface

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SAW touchscreen

PrincipleSurface waves are readily absorbedwhen a soft object such as a fingertiptouches the substrate.

SAW Touch Screenuse pure glasswith transmitting and receivingpiezoelectric transducers for both theX and Y axes.

When you touch the screen, youabsorb a portion of the wavetraveling across it. The receivedsignal is then compared to the storeddigital map, the change recognized,and a coordinate calculate.

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SAW touchscreen

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SAW touchscreen Characters:

1. Durable glass construction

2. High optical clarity3. Activated by a finger, gloved hand or soft tip

4. Not completely sealable, can be affected by large amounts of dirt,dust, and / or water in the environment

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Technology Capacitive SAW Infrared Resistive

Transparence Very good>92%

Very good

>92%Very good

>92%75%~85%

Resolution Good Good Limited due tospacing of IR

sensors

good

Surface

Contaminants

/durability

Resistant to

moisture and

other surfacecontaminants

Adversely

affected by

moisture orSurface

contaminants

Potential for

False activation

or dead zonesFrom Surface

Contaminants

Unaffected by

Surface

contaminants.Polyester top

sheet is easily

scratched

Sensor substrate Glass with ITOcoating

Glass with ITO

coatingAny substrate Polyester top

sheet, glass

substrate withITO coating

Display size 8.4"-21" 10.4"-30" 10.4"-60" up to 19"

Touch method Human touch finger, gloved

hand or soft tip

Can use any

pointing deviceCan use any

pointing device

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Here are a few examples of how touch input systems

are being used today:

1. Public Information Displays

Information kiosks, tourism displays, trade show displays, and otherelectronic displays are used by many people that have little or nocomputing experience.

2. Retail and Restaurant SystemsTime is money, especially in a fast paced retail or restaurant

environment. Touch screen systems are easy to use so employees

can get work done faster, and training time can be reduced for new

employees.

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3. Customer Self-ServiceIn today's fast pace world, waiting in line is one of the things that

has yet to speed up. Self-service touch screen terminals can be used toimprove customer service at busy stores, fast service restaurants,transportation hubs, and more.

4. Control and Automation Systems

The touch screen interface is useful in systems ranging fromindustrial process control tc home automation. By integrating the

input device with the display, valuable workspace can be saved

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What is 4G? Abbreviation of fourth generation wireless technology.

It will provide a comprehensive IP solution where voice , data

and multimedia can be given to user on an anytime ,anywhere basis.

It includes several types of broadband wireless communication

system access including cellular telephone system.

It will provide seamless mobility and internet access at a rate of

100 Mbps.

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Features of 4G Support for multimedia services like teleconferencing and

wireless

internet.

Wider bandwidths and higher bitrates.

Entirely packet-switched network.

Global mobility and service portability.

Support for previous wireless technologies.

High internet speed.

tight network security

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Technologies used in 4GOFDM

UWB

Smart antennas

IPv6

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OFDM (Orthogonal frequency

division multiplexing) IT transmits large amounts of digital data over a radio wave.

OFDM works by splitting the radio signal into multiple smallersub-signals that are then transmitted simultaneously at differentfrequencies to the receiver .

By inserting a cyclic prefix between adjacent OFDM signal intersignal interference is virtually eliminated if the max. channeldelay spread is less than the time interval of cyclic prefix.

In OFDM the subcarrier pulse used for transmission is

rectangular. Here modulation can performed by an IDFT ,which can be

generated very efficiently as an IFFT . so, receiver only needs aFFT to reverse this process

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UWB (Ultra Wide Band) An advanced technology that can be used in 4G

technology.

It is typically detected as noise.

It can use any part of the frequency spectrum, which meansthat it can use frequencies that are currently in use by otherradio frequency devices .

It uses a frequency of 3.1 to 10.6 Hz.

It uses less power , since it transmits pulse instead ofcontinuous signal.

Special antennas are needed to tune and aim the signal.

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Smart Antennas Smart antenna can be employed to find tune ,and turn up signal

information. Smart antenna can send signal back in the same direction that

they come from.

There are two types of smart antennas- Switched beam antenna:-It has fixed beams of transmission, and

switch from predefined beam to another when the user with thephone moves throughout the sector.

Adaptive array antenna :-It represents the most advanced smart

antenna approach to data using a variety of new signal Itrepresent the most advanced smart antenna approach to dateusing avariety of new signal processing algorithms to locate andtrack the user, minimize interference and maximize intendedsignal reception.

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IPv6 IPv6 means Internet Protocol Version 6 .

The Internet Protocol (IP) is the method or protocolby which data is sent from one computer to another onthe internet.

Each computer (known as a host) on the Internet hasat least one IP that uniquely identifies it from all other

computers on the Internet. Itincludes128 bits, which is 4 times more than 32bits IP

address in IPv4.

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Quality of Service In wireless networks, Quality of Service (QOS) refers to the

measure of the performance for a system reflecting itstransmission quality and service availability.

4G is expected to have at least a reliability of 99.99%.

In 4G QOS may be divided in following ways-

Transaction-level QOS describes both the time it takes to

complete a transaction and the packet loss rate. Circuit-level QOS includes call blocking for new as well as

existing calls .

User-level QOS depends on user mobility and application type .

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Applications In traffic control.

location application.

Telemedicine. In crisis management application

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Thank You

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final touch screen sensor

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