The document discusses touchscreen technology. It begins by defining a touchscreen as a display that can detect touch input, allowing users to interact directly on the screen. It then covers the history and evolution of touchscreen development from the 1960s to modern smartphones and tablets. The key components of a touchscreen like the touch sensor, controller, and software driver are explained. Different types of touchscreen technologies such as resistive, capacitive, infrared and surface acoustic wave are described along with their advantages and applications. The document concludes by discussing future trends towards replacing mice and keyboards with touch interfaces.

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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 & allowing a user to
interact with the computer by touching
pictures or words on the screen.
Touchscreen can also sense other
passive objects, such as a stylus.

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1. It enables one to interact with what
is displayed directly on the screen,
where it is displayed, rather than
indirectly with a mouse or touchpad.
2. It lets one do so without requiring
any intermediate device, again,
such as a stylus that needs to be
held in the hand. Such displays can
be attached to computers or, as
terminals, to networks.

5. ● Touchscreens emerged from academic and corporate
research labs in the second half of the 1960s.
● Invented by E.A. Johnson (Royal Radar Est.) around
1965 for air traffic control
● 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 from1983 was probably the world's earliest
commercial touch screen computer.
● It doesn't actually have a touch screen 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.
● 1993 Apple’s Newton and IBM’s Simon & 2002
Microsoft’s Windows XP Tablet &2007 Apple’s iPhone
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6.  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.
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Main touch screen components:
1. Touch sensor
2. Controller
3. Software driver

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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.
TOUCHSENSOR

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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.

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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 .

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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.

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 Resistive Touch screen
 Surface wave Touch screen
 Capacitive Touch screen
* Surface capacitive
* Projected capacitive
 Near Field Imaging Touch screen
 Infrared Touch screen

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RESISTIVE TOUCH SCREENS
 The resistive touch screen uses a
glass panel with a uniform conductive
ITO(Indium Tin Oxide) coating on the
side surface.
 Two layers of conductive material.
 Touch creates contact between
resistive layers completing circuit.
 Voltage in circuit changes based on
position.
 Controller determines location based
on voltages.
 Any material can trigger sensors.

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● 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 touch screen deliver cost-effective, consistent and
durable performance.
Working Principle :

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Surface Acoustic Wave:
 Electrical signals sent to the
transmitting transducers converts
to ultrasonic waves
 Waves are directed across screen
by reflectors then directed to
receiving transducers
 The SAW controller sends a 5 MHz
electrical signal to the X-axis and
Y-axis transmitting transducers.
When the touch screen is touched, the finger absorbs a
portion of the wave passing across the surface of the panel.
SAW can be used in any and all applications for the best
possible image clarity an unlimited life.

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 Capacitive touch screen 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, 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).

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Infrared:
 Conventional optical-touch
systems use an array of infrared
(IR) light-emitting diodes (LEDs)
on two adjacent bezel edges of a
display, with photo sensors
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.

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Technology Resistive SAW Infrared Capacitive
Durability: 5 years 5 years 3 years 2 years
Stability: High Higher High Ok
Transparency: Very good >92% Very good >92% Very good >92% 75%~85%
Touch: Anything Finger/ pen Sharp Conductive
Response
time:
<10ms 10ms <20ms <15ms
Example

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Advantages :
 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.

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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.

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Museums.
Corporate information.
 Library resource guides.
Shopping mall directory.
Public Information Displays.
 Public transportation schedule / status.
Automated travel and entertainment ticket dispensers.
Airport terminal passenger internet and email systems.

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 As we all knows today’s
smartest phone is i-phone
which is working on
touchscreen which is next
generation phone.
 Also Microsoft surface is
best example for it today
we all are familiar with it.
 Which is going to be next
generation computing
technique.

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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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