The document discusses different types of touch screen technologies, including resistive, capacitive, surface acoustic wave, and infrared screens. It describes the key components of a touchscreen system and how each technology detects and locates touch input. Resistive and capacitive screens are the most common. The document also outlines common applications of touchscreens and concludes that the market continues to grow as touch sensors are integrated into more display products.

1. Touch Screen Technologies
Abhiram Kumar

2. Contents:
•What are Touch Screens?
•History and Development
•Elements of a Touchscreen System
•Touch Screen Technologies
•Application of Touch Screens
•Advantages
•Disadvantages
•Conclusion

3. What are Touch Screens?
•A touch screen is an electronic visual display that can detect
the presence and location of a touch within the display area.
•Most user friendly input medium
used to interface with a device.
•The user touches the screen to select
options presented on it, where
associated hardware and software
locate that touch.
• Direct manipulation type gesture
based technology.

4. Elements of a touch screen

5. 1. Touch sensor
• The touch sensor is a clear glass
panel with a touch responsive
area and it is placed over
the display screen.
• It allows the electric current and
signal to pass through it and
change in these signal is used
to detect the location of touch
on the screen.

6. 2. Controller
• The controller connects
between the touch sensor and
the PC.
• It takes information from the
touch sensor and translate it
into the information that PC
can understand.

7. 3. Software Driver
• The driver is a software that allows the touch
screen and the 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 a mouse-
emulation type driver. This makes touching the
screen the same as clicking your mouse at the
same location on the screen.

8. Touch Screen Technologies

9. Touch Screen Technologies
• Resistive
• Capacitive
• Surface Acoustic Wave (SAW)
• Infrared LED or Optical

10. Resistive Touch Screens
• Consists of two layers:
1. Conductive Layer
2. Resistive Layer
• Conductive layer, always has
current flowing inside it.
• Resistive layer interfaces
the screen to the outer
world.

11. • With a light touch, the conductive coating makes electrical
contact with the coating on the glass.
• The voltages at the point of contact are the analog
representation of the position touched.
• The controller digitizes these voltages and transmits them to
the computer for processing.

12. Advantages of Resistive touch screens :
• 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.
Disadvantages of Resistive touch screens :
• Resistive layers can be damaged by a sharp object.
• Ambient light effect.

13. Capacitive Touch screen
•Work with anything that stores
charge, including human skin.
•Made from materials like Indium
Tin Oxide, which stores electric
charges in ac grid,
made of tiny wires.
• Electrostatic grid is made of
driving line and sensing line.
• Beneath the driving line lies
sensing line orthogonal to it.

14. Capacitive Touch screen
• Upgrades:
1. On-cell
(Super Amoled)
2. In-cell
(Iphone 5s)

15. Advantages of Capacitive touch screens :
• Durable surface material
• High endurance (~255 million touches)
• Very accurate
• Good optical quality
Disadvantages of Capacitive touch screens :
• Triggered only by bare finger or active stylus.

16. Surface Acoustic Wave Touch screen
• When a touch occurs, the wave is absorbed shortening the
echo time it takes to reach the receivers.
• Made of a glass overlay with transmitting and
receiving piezoelectric transducers for both the X
and Y axes.

17. 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

18. Infrared Touch Screens
• In the Infrared
Touchscreen Technology,
an array of X- and Y- axes
are fitted with pairs of IR
Leds and photo detectors.
• The photo detectors detect
any change in the pattern
of light emitted by the
Leds whenever the user
touches the
monitor/screen

19. Advantages of Infrared :
• Highest quality of underlying image.
• Excellent anti-glare, with use of chemically etched glass.
• Can be activated with almost any device.
• Higher accuracy than other technologies.
• Very high durability and reliability.
Disadvantages of Infrared :
• Surface obstructions can cause a false touch.
• It is very sensitive and can be activated by stray touches.
• Gives Parallax problems.

20. Capacitive SAW Infrared Resistive
Transparence Very good
>92%
Very good >92% Very good >92% 75%~85%
Resolution Good Good Limited due to
spacing of IR
sensors
good
Surface
Contaminant
/Durability
Resistant to
moisture and
other surface
contaminants
Adversely
affected by
moisture or
Surface
contaminants
Potential for
False activation
or dead zones
From Surface
Contaminants
Unaffected by
Surface
contaminants.
Polyester top
sheet is easily
scratched
Sensor
substrate
Glass with ITO
coating
Glass with ITO
coating
Any substrate Polyester top
sheet, glass
substrate with
ITO 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 device
Can use any
pointing device
Comparison Chart :

21. Application 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

22. Conclusion :
•Touch systems represent a rapidly growing subset
of the display market.
•The majority of touch systems include touch
sensors relying on vacuum-deposited coatings, so
touch coatings present opportunity for suppliers of
vacuum coatings and coating equipments.
•Touch sensor manufactures currently require thin
films in the areas of transparent conductors, optical
interference coating and mechanical protective
coatings.

23. References :
•https://en.wikipedia.org/wiki/Touchscreen
•https://www.studymafia.org/touchscreen
•http://www.engineersgarage.com/articles/touchscreen
-technology-working
• Britlab: How touchscreen works?