Touch Screen Teechnology

1. Touch Screen
Technology
RESEARCHER: RAZZESH SHAH.
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2. What are Touch Screens ?
 It is the most user friendly input device used to interface with a
PC.
 The user touches the screen
to select options presented
on it, where associated hardware and software locate that
touch.
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3. History and Development
 In 1971 Dr. Sam Hurst, founder of Elographics
developed the first touch opaque sensor
“Elograph” at the University of Kentucky.
 In 1974 He developed the first real touch
screen.
 In 1977, Elographics developed the five-wire
resistive technology then with the backing of
Siemens Corporation, developed a curved
glass sensor called the touch screen.
 The new transparent technology, AccuTouch,
was later developed by the founders of
Elographics, Dr. Hurst and Bill Colwell.
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4. Why use Touch Screens ?
 Enable first-time users to interface with computers
instantly, without any training.
 Eliminate operator errors because users make
selections from clearly defined menus.
 Eliminate keyboards and mice, which many
novice users find difficult to use.
 Rugged enough to stand up to harsh conditions
where keyboards and mice can be damaged.
 Provide fast access to all types of digital content.
 Ensure that no space is wasted since the input
device is completely integrated into the monitor.
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5. Elements of a touchscreen system
 The touchscreen itself.
 A computer whose display is fitted with the
touchscreen interefacing with.
 A controller drives the touchscreen and
converts each touch into X/Y coordinates.
 A software driver, which communicates
between the controller card and the
computer's operating system.
 Application-development software, which
enables developers of touch programs to build
their own applications and/or customize existing
touch applications.
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6. How do Touchscreens Work?
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7. TOUCH TECHNOLOGIES
Here are some technologies that are used in making
touch screens:
 Resistive
 Capacitive
 Surface Acoustic Wave (SAW)
 Scanning Infrared
 Near Field Imaging
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8. Resistive touch screen
 Made of a glass panel with a coating of uniform
resistivity on which a voltage is applied. A
polyester cover sheet is tightly suspended over the
top of the glass, separated from it by small,
transparent insulating dots.
 The cover sheet has a hard, durable coating on
the outer side and a conductive coating on the
inner side.
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9.  With a light touch, the conductive coating makes
electrical contact with the coating on the glass.
 The voltages at the point ofcontact are the analog
representation of the position touched. The
controller digitizes these voltages and transmits
them to the computer for processing.
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10. Advantages of Resistive
– High Resolution and Accuracy
– Fast Response
– Pressure-activated by finger or gloved hand with a very
light touch
– Durable hard-coat front surface can be nonglare treated
for reflection control or polished for maximum clarity
– Touchscreens and controllers are safety agency-
approved components,so certification of your system is
easier
Disadvantages of Resistive
– 80 % Clarity
– Resistive layers can be damaged by a sharp object
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11. Capacitive Touch screen
There are 2 types of capacitive touch screens:
Surface capacitive
-consists of a uniform conductive coating on a glass
panel on which a low voltage is evenly applied fromthe
corners.
-The touch location is measured from the ratio of the
current flow from the corners
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13. Projected Capacitive
-Made of a front and back protective glass
providing optical and strength enhancement
options.
-Its middle layer consists of a laminated sensor grid
of micro-fine wires and optical enhancement
options.
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14. Advantages of Capacitive
– High Touch Resolution
– High Clarity
– Completely Sealable
Disadvantages of Capacitive
– Must be touched by finger- will not work with any
non- conductive input
– Can be affected by electricity
– May need re-calibration often
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15. Surface Acoustic Wave Touch screen
 Made of a glass overlay with transmitting
and receiving piezoelectric transducers for
both the X and Y axes.
 When a touch occurs, the wave is absorbed
shortening the echo time it takes to reach
the receivers.
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16. Advantages of Surface Acoustic Wave
Excellent Image Clarity -Very High
LightTransmission
Excellent Durability -Stable "No-Drift" Operation
High Resolution - Very Light Touch
Fast Touch Response -X,Y and Z-axis Response
Finger or Gloved-Hand Operation
Disadvantages of Surface Acoustic Wave
Must be touched by finger, gloved hand, or soft-tip
stylus. Something hard like a pen won't work
Not completely sealable, can be affected by
large amounts of grease, water, or dirt on the
touchscreen
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17. Scanning Infrared touch
screen
 Made of a grid of LEDs and detectors framed to
the front of the display that projects horizontal
and vertical beams of infrared light.
 The press location is determined since it
obstructs the IR beam
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18. Advantages
– Mostly used in manufacturing and medical applications since it
can be completely sealed.
– operated using a stylus or a gloved finger.
– mechanically stronger
– Clearer
– more wear resistant
Disadvantages
– it is very sensitive and can be activated by stray touches.
– Low resolution
– Parallax problems
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19. Near Field Imaging touch
screen
 Made of two laminated glass sheets having a
transparent metal oxide coating in between.
 An AC signal is applied to the patterned
conductive coating creating an electrostatic
field on the surface of the screen.
 It is used only in the toughest environments and
applications due to its high cost.
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20. Applications of Touch Screens
Informational kiosks
Trade show displays
Museum / tourism displays
Point-of-sale terminals
Restaurant systems
Employee time clocks
Industrial process controls
World Wide Web access kiosks
Home automation systems
Casino and other gaming systems
Computer access for the physically disabled
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21. Thank you Sir !
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