Transcript firewall for computer networks

TOUCH SCREEN
TECHNOLOGY
Subrat kumar Moharana
Regd. No:-0711016018
ENTC-A
TALK FLOW
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INTRODUCTION
HISTORY
FUNCTIONS
WORKING
TOUCH SCREEN TECHNOLOGY
APPLICATION
CONCLUSION
INTRODUCTION
A touch screen is a computer display screen
that is sensitive to human touch, allowing a
user to interact with the computer by
touching pictures or words on the screen.
A touch screen is an input device that allows
users to operate a PC by simply touching
the display screen which has a sensitive
glass overlay placed on it .
A touch screen accepts direct onscreen
inputs.
HISTORY
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In 1971, the first "touch sensor" was developed
by Doctor Sam Hurst (founder of Elographics)
while he was an instructor at the University of
Kentucky.
The University of Kentucky Research
Foundation named it as “Elograph”.
The "Elograph" was not transparent like
modern touch screens.
In 1974, the first true touch screen
incorporating a transparent surface came.
HOW DOES A TOUCHSCREEN
WORK?
A basic touch screen has three main
components:
 touch sensor
 controller
 software driver
1.TOUCH SENSOR
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A touch screen sensor is a clear glass panel
with a touch responsive surface which is
placed over a display screen.
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The sensor generally has an electrical current
or signal going through it and touching the
screen causes a voltage or signal change. This
voltage change is used to determine the
location of the touch to the screen.
2.CONTROLLER
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The controller is a small
PC card that connects
between the touch
sensor and the PC.
It takes information
from the touch sensor
and translates it into
information that PC can
understand.
3.SOFTWARE DRIVER
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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 is sent from
the controller.
Most touch screen drivers today are mouseemulation type drivers. This makes touching
the screen the same as clicking your mouse at
the same location on the screen.
DIFFERENT TOUCH SCREEN
TECHNOLOGIES
RESISTIVE
 CAPACITIVE
 SURFACE WAVE
 INFRARED
 DISPERSIVE SIGNAL
TECHNOLOGY
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RESISTIVE TOUCH SCREEN
TECHNOLOGY
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Polyester Film .
Top Resistive Layer.
Conductive Transparent Metal Coating.
Bottom Resistive Layer .
Insulating Dots .
Glass Substrate
Contd.
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Pressing the flexible top sheet creates electrical
contact with the coating on the glass.
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The touch screen controller gets the
alternating voltages between the two layers
and converts them into the digital X and Y
coordinates of the activated area.
Working of touch screen in an
integrated circuit
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In case of measurement of X coordinate ,the
top sheet caries a voltage gradient generated
by applying a voltage between the electrodes
of top sheet .the bottom sheet serve as a slider
in a linear potentiometer .The X co-ordinate is
estimated considering the equivalent resistance
between the touch point to each linear
electrode in top sheet.
Internal Structure
Implementation
X1=k(Vrtl+Vrtr+Voffset)
X2=k(Vrtl+Voffset)
X3=k Voffset
The x-coordinate is calaulated from:
X=(X2-X3)/(X1-X3)
similarly;
Y=(Y2-Y1)/(Y1-Y3)
Equivalent Resistance
Block diagram
Advantages of Resistive
Technology
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Can be activated with any device
Low cost solution
Low power consumption
Disadvantages of Resistive
Technology
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Poor durability
Lower resolution
Less Accuracy
APPLICATIONS
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Public Information Displays
tourism displays, trade show displays
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Customer Self-Service
stores, restaurants, transportation hubs, ATM and
airline e-ticket terminals.
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And many more uses...
computerized gaming, student registration
systems, multimedia software, financial and
scientific applications, and more.
CONCLUSION
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Touchscreens, touch panels or touchscreen
panels are display overlays which have the
ability to display and receive information on
the same screen.
Touchscreens also have assisted in recent
changes in the PDAs, making these devices
more usable.
REFERENCES
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[ 11 Sandbach, David Lee: Position detector constructed
from fabric, European patent EP 0989509A2
[2] Microtouch Systems, Inc.: Frontally Shielded Capacitive
touch sensor system, United States Patent US5457289
[3] Summagraphics Corporation: Method and apparatus for calibration of a charge
ratio digitizer, United States Patent US483 1566
[4] Microtouch Systems, Inc.: Touchscreen controller with pen andor finger inputs,
United States Patent US5457289
[5] Peptek, Incorporated: Touch panel system and Method, United states Patent
US4353552