Rajesh Kumar Sahoo submitted a seminar on touch screen and touchless technology. The document defines touch screens as input devices that allow users to interact directly with displayed content by touching the screen. It discusses the history and development of touch screens, including the first touch screen created in 1971. The document outlines different touch screen technologies like resistive, capacitive, surface acoustic wave, and infrared. It also covers the components and working of touch screen systems. Applications of touch screens and touchless technology are presented, along with their advantages and disadvantages. The conclusion is that touch systems are growing but touchless technology is still being developed for high precision input.

1. Submitted By
Rajesh Kumar Sahoo
1304316
ETC
Seminar
On
Touch Screen &
Touchless
Technology

2. Content
 What are Touch Screens?
 History and Development
 Why use Touch Screen
 Elements of a Touchscreen System
 Touch Screen Technologies
 Application of Touch Screens
 Advantages
 Disadvantages
 Tour to Touchless technology
 Touchless technology workflow
 Applications of touchless technology
 Conclusion

3. 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.

4. 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.

5. Why use Touch Screens?
 It allows users to interact directly with the
diplayed content rather than using indirect mouse
or any pointing devices.
 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.

7. How does a Touch screen Work?
Main touch screen components:
 Touch sensor
 Controller
 Software driver

8. Touch sensor
 A touch screen sensor is a clear glass panel with
a touch responsive surface.
 The touch sensor/panel is placed over a display
screen so that the responsive area of the panel
covers the viewable area of the video screen.
 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.

10. Controller
 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.
 The controller is usually
installed inside the monitor
for integrated monitors or it
is housed in a plastic case
for external touch add-
ons/overlays

11. 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 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.

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

13. Resistive Touch Screens
 It is constructed of two transparent layer coated with conducted
material.When pressure is applied by a finger, the top layer
makes contact wit the lower layer.When a voltage is applied
across one layer a volatage divider is created.
 And this way the coordinate then detected through x and y axis.

14. Advantages of Resistive
High Resolution and Accuracy
Fast Response
Pressure-activated by finger or gloved hand with a very light
touch
Disadvantages of Resistive
80 % Clarity
Resistive layers can be damaged by a sharp object

15. Capacitive Touch screen
There are 2 types of capacitive touch screens:
Capacitive : That is due to electrostatic distortion on the screen
capacitance got changed and according position get detected
Surface capacitive
-consists of a uniform conductive coating on a glass panel
on which a low voltage is evenly applied from the corners.
-The touch location is measured from the ratio of the
current flow from the corners

16. Diagram showing How it Works

17. Advantages:
Durable surface material
High endurance (~255 million touches)
Very accurate
Good optical quality
Disadvantages:
Triggered only by bare finger or active stylus

18. Surface Acoustic Wave
Touch screen
 Surface acoustic wave technology
uses Ultrasonic waves that pass over the
touchscreen panel. When the panel is touched, a
portion of the wave is absorbed. This change in
the ultrasonic waves says the position of the touch
event .

19. 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

20. Infrared Touch Screen

21. Application of Touch Screens
 Laptop and mobile accessories
 Trade show displays
 Museum / tourism displays
 Point-of-sale terminals
 Restaurant systems
 Industrial process controls
 Home automation systems
 Computer access for the physically disabled

22. Pros & Cons
 Direct pointing to the objects.
 Fast
 Finger or pen is usable (No
cable required)
 No keyboard necessary
 Suited to: novices, application
for information retrieval etc
 Low precision by using finger
 User has to sit or stand closer
to the screen
 The screen may be covered
more by using hand
 If screen is cracked then
touchpad may not work
which touchless technology
can be a boon for it.

23. Touchless Touch screen

24. Moving
Images in
front of the
sensor
Detected
by the
sensor
Light enters to
the sensor and
hits the pixel
matrix
Signals are
processed by
a DIP to
provide
output to the
devices
The sensor
generates
electric signals
The photodiodes
inside the pixel
converts
incoming light
into electric
charge

25. Applications
3D Navigation of Hand Movements e.g. project soli
in Touchless Screen

26. Conclusion
 Touch systems represent a rapidly growing
subset of the display market.
 The devices which we use in our daily life
are mainly capacitive type.
 Touchless Technology is still developing
 Chip makers are on the way to develop
high precision touchless input devices

27. Any Question????

28. Thanks