Presentation On Touch Screen

1. GENERALGENERAL
PRESENTATIONPRESENTATION
ONON
TOUCHSCREENTOUCHSCREEN
Neeraj DhimanNeeraj Dhiman

2. What is TouchscreenWhat is Touchscreen
 An input/output device that accept input directly from theAn input/output device that accept input directly from the
monitor , the user touches words, graphical icons, ormonitor , the user touches words, graphical icons, or
symbols displayed on screen to activate commands.symbols displayed on screen to activate commands.
 A touch screen is a computer display screen that is sensitiveA touch screen is a computer display screen that is sensitive
to human touch, allowing a user to interact with theto human touch, allowing a user to interact with the
computer by touching pictures or words on the screen.computer by touching pictures or words on the screen.

3. History of TouchscreenHistory of Touchscreen
 In 1971, the first "touch sensor" was developed by Doctor SamIn 1971, the first "touch sensor" was developed by Doctor Sam
Hurst (founder of Elographics) while he was an instructor atHurst (founder of Elographics) while he was an instructor at
the University of Kentucky. This sensor called the "Elograph"the University of Kentucky. This sensor called the "Elograph"
was patented by The University of Kentucky Researchwas patented by The University of Kentucky Research
Foundation.Foundation.
 In 1974, the first true touch screen incorporating a transparentIn 1974, the first true touch screen incorporating a transparent
surface came on the scene developed by Sam Hurst andsurface came on the scene developed by Sam Hurst and
Elographics. In 1977, Elographics developed and patentedElographics. In 1977, Elographics developed and patented
five-wire resistive technology, the most popular touch screenfive-wire resistive technology, the most popular touch screen
technology in use today.technology in use today.
 On February 24, 1994, the company officially changed itsOn February 24, 1994, the company officially changed its
name from Elographics to Elo TouchSystems.name from Elographics to Elo TouchSystems.

4. How Does A Touchscreen worksHow Does A Touchscreen works
A basic Touchscreen has three main components:A basic Touchscreen has three main components:
 A Touch sensorA Touch sensor
 A ControllerA Controller
 A Software driverA Software driver..

5. 1. Touch Sensor1. Touch Sensor A touch screen sensor is a clear glassA touch screen sensor is a clear glass
panel with a touch responsive surface.panel with a touch responsive surface.
The touch sensor/panel is placed over aThe touch sensor/panel is placed over a
display screen so that the responsivedisplay screen so that the responsive
area of the panel covers the viewablearea of the panel covers the viewable
area of the video screen.area of the video screen.
 There are several different touch sensorThere are several different touch sensor
technologies on the market today, eachtechnologies on the market today, each
using a different method to detect touchusing a different method to detect touch
input.input.
 The sensor generally has an electricalThe sensor generally has an electrical
current or signal going through it andcurrent or signal going through it and
touching the screen causes a voltage ortouching the screen causes a voltage or
signal change. This voltage change issignal change. This voltage change is
used to determine the location of theused to determine the location of the
touch to the screen.touch to the screen.

6. 2. Controller2. Controller
 The controller is a small PC card thatThe controller is a small PC card that
connects between the touch sensor and theconnects between the touch sensor and the
PC. It takes information from the touchPC. It takes information from the touch
sensor and translates it into informationsensor and translates it into information
that PC can understand.that PC can understand.
 The controller is usually installed insideThe controller is usually installed inside
the monitor for integrated monitors or it isthe monitor for integrated monitors or it is
housed in a plastic case for external touchhoused in a plastic case for external touch
add-ons/overlays.add-ons/overlays.
 The controller determines what type ofThe controller determines what type of
interface/connection you will need on theinterface/connection you will need on the
PC. Specialized controllers are alsoPC. Specialized controllers are also
available that work with DVD players andavailable that work with DVD players and
other devices.other devices.

7. 3. Software Driver3. Software Driver
 The driver is a software updateThe driver is a software update
for the PC system that allowsfor the PC system that allows
the touchscreen and computerthe touchscreen and computer
to work together. It tells theto work together. It tells the
computer's operating systemcomputer's operating system
how to interpret the touch eventhow to interpret the touch event
information that is sent frominformation that is sent from
the controller.the controller.
 Most touch screen drivers todayMost touch screen drivers today
are a mouse-emulation typeare a mouse-emulation type
driver. This makes touching thedriver. This makes touching the
screen the same as clickingscreen the same as clicking
your mouse at the sameyour mouse at the same
location on the screen.location on the screen.

8. Touchscreen TechnologiesTouchscreen Technologies
There are basically three types of touch screenThere are basically three types of touch screen
technologies:-technologies:-
 ResistiveResistive
 CapacitiveCapacitive
 Surface waveSurface wave

9. Resistive Touchscreen TechnologyResistive Touchscreen Technology
 The Resistive system consists of a normalThe Resistive system consists of a normal
glass panel that is covered with aglass panel that is covered with a
conductive and a resistive metallic layer.conductive and a resistive metallic layer.
These two layers are held apart by spacers,These two layers are held apart by spacers,
and a scratch-resistant layer is placed onand a scratch-resistant layer is placed on
top of the whole setup.top of the whole setup.
 An electrical current runs through the twoAn electrical current runs through the two
layers while the monitor is operational.layers while the monitor is operational.
When a user touches the screen, the twoWhen a user touches the screen, the two
layers make contact in that exact spot.layers make contact in that exact spot.
 The change in the electrical field is notedThe change in the electrical field is noted
and the coordinates of the point of contactand the coordinates of the point of contact
are calculated by the computer. Once theare calculated by the computer. Once the
coordinates are known, a special drivercoordinates are known, a special driver
translates the touch into something that thetranslates the touch into something that the
operating system can understand, much as aoperating system can understand, much as a
computer mouse driver translates a mouse'scomputer mouse driver translates a mouse's
movements into a click or a drag.movements into a click or a drag.

10. Capacitive Touchscreen TechnologyCapacitive Touchscreen Technology
 The Capacitive, a layer that stores electricalThe Capacitive, a layer that stores electrical
charge is placed on the glass panel of thecharge is placed on the glass panel of the
monitor. When a user touches the monitor withmonitor. When a user touches the monitor with
his or her finger, some of the charge ishis or her finger, some of the charge is
transferred to the user, so the charge on thetransferred to the user, so the charge on the
capacitive layer decreases.capacitive layer decreases.
 This decrease is measured in circuit located atThis decrease is measured in circuit located at
each corner of the monitor. The computereach corner of the monitor. The computer
calculates, from the relative differences in chargecalculates, from the relative differences in charge
at each corner, exactly where the touch eventat each corner, exactly where the touch event
took place and then relays that information to thetook place and then relays that information to the
touch-screen driver software.touch-screen driver software.
 Advantage :-It transmits almost 90 percent ofAdvantage :-It transmits almost 90 percent of
the light from the monitor, whereas the resistivethe light from the monitor, whereas the resistive
system only transmits about 75 percent. Thissystem only transmits about 75 percent. This
gives the capacitive system a much clearergives the capacitive system a much clearer
picture than the resistive system.picture than the resistive system.

11. Surface Acoustic Wave TouchscreenSurface Acoustic Wave Touchscreen
TechnologyTechnology
 A surface acustic wave technology, two transducer (oneA surface acustic wave technology, two transducer (one
receiving and one sending) are placed along the x and y axes ofreceiving and one sending) are placed along the x and y axes of
the monitor's glass plate. Also placed on the glass are reflector --the monitor's glass plate. Also placed on the glass are reflector --
they reflect an electrical signal sent from one transducer to thethey reflect an electrical signal sent from one transducer to the
other.other.
 The receiving transducer is able to tell if the wave has beenThe receiving transducer is able to tell if the wave has been
disturbed by a touch event at any instant, and can locate itdisturbed by a touch event at any instant, and can locate it
accordingly.accordingly.
 The wave setup has no metallic layers on the screen, allowing forThe wave setup has no metallic layers on the screen, allowing for
100-percent light throughput and perfect image clarity. This100-percent light throughput and perfect image clarity. This
makes the surface acoustic wave system best for displayingmakes the surface acoustic wave system best for displaying
detailed graphics (both other systems have significantdetailed graphics (both other systems have significant
degradation in clarity).degradation in clarity).

12. Comparing Touchscreen TechnologiesComparing Touchscreen Technologies
 4-Wire Resistive Touch screens4-Wire Resistive Touch screens
 5-Wire Resistive Touchscreens5-Wire Resistive Touchscreens
 Capacitive TouchscreensCapacitive Touchscreens
 PenTouch Capacitive TouchscreensPenTouch Capacitive Touchscreens

13. 4-Wire Resistive Touch screens4-Wire Resistive Touch screens
 4-Wire Resistive touch technology4-Wire Resistive touch technology
consists of a glass or acrylic panelconsists of a glass or acrylic panel
that is coated with electricallythat is coated with electrically
condictive and resistive layers.condictive and resistive layers.
 The thin layers are separated byThe thin layers are separated by
invisible separator dots. Wheninvisible separator dots. When
operating, an electrical currentoperating, an electrical current
moves through the screen.moves through the screen.
 When pressure is applied to theWhen pressure is applied to the
screen the layers are pressedscreen the layers are pressed
together, causing a change in thetogether, causing a change in the
electrical current and a touchelectrical current and a touch
event to be registered.event to be registered.

14. 5-Wire Resistive Touchscreens5-Wire Resistive Touchscreens
 5-Wire Resistive touch5-Wire Resistive touch
technology consists of a glass ortechnology consists of a glass or
acrylic panel that is coated withacrylic panel that is coated with
electrically condictive andelectrically condictive and
resistive layers.resistive layers.
 The thin layers are separated byThe thin layers are separated by
invisible separator dots. Wheninvisible separator dots. When
operating, an electrical currentoperating, an electrical current
moves through the screen.moves through the screen.
 When pressure is applied to theWhen pressure is applied to the
screen the layers are pressedscreen the layers are pressed
together, causing a change in thetogether, causing a change in the
electrical current and a touchelectrical current and a touch
event to be registered.event to be registered.

15. Capacitive TouchscreensCapacitive Touchscreens
 A capacitive touch screenA capacitive touch screen
consists of a glass panel with aconsists of a glass panel with a
capacitive (charge storing)capacitive (charge storing)
material coating its surface.material coating its surface.
Circuits located at corners of theCircuits located at corners of the
screen measure the capacitancescreen measure the capacitance
of a person touching the overlay.of a person touching the overlay.
 Frequency changes are measuredFrequency changes are measured
to determine the X and Yto determine the X and Y
coordinates of the touch event.coordinates of the touch event.

16. PenTouch CapacitivePenTouch Capacitive
TouchscreensTouchscreens The PenTouch Capacitive screen is aThe PenTouch Capacitive screen is a
durable Capacitive type touchscreendurable Capacitive type touchscreen
with an attached pen stylus. Thewith an attached pen stylus. The
PenTouch screen can be set to respondPenTouch screen can be set to respond
to finger input only, pen input only, orto finger input only, pen input only, or
both.both.
 A capacitive touch screen consists of aA capacitive touch screen consists of a
glass panel with a capacitive (chargeglass panel with a capacitive (charge
storing) material coating its surface.storing) material coating its surface.
Circuits located at corners of the screenCircuits located at corners of the screen
measure the capacitance of a personmeasure the capacitance of a person
touching the overlay.touching the overlay.
 Frequency changes are measured toFrequency changes are measured to
determine the X and Y coordinates ofdetermine the X and Y coordinates of
the touch event.the touch event.

17. THANKSTHANKS
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