1. Henri Legentil Thomas Zubeli
Tactile devices
Henri Legentil
Thomas Zubeli

2. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion

3. Introduction Why this topic? What is included in “tactile devices”?
- At first, quite a new technology even if we’ll see that not that new.
- Get out of the pure “computer domain” (we’ll see applications)
Basically, everything that can be controlled by the touch.
But we are gonna give a more precise definition... -> (next slide)

4. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion

5. Definition
“Device fitted with a system which enables to execute actions by finger-pointing areas on a delimited zone.”
General structure:
Sensors
Controller
Software
Structure:
Sensors
Controller: always an electronic card linked by a flexible cable
Software: most of the time a computer

6. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion

7. History 1960s: Academic & corporate researches
1971: 1st “touch sensor” by Sam Hurst (founder of Elographics): “Elograph”
1974: 1st transparent touch screen
1983: 1st commercial touch screen
computer HP-150
1970s-1980s:
all significant technologies
Emerged from academic and corporate research labs: second half of the 1960s.
1971: first "touch sensor" developed by Dr Sam Hurst, founder of Elographics, company that has made most of the discovers and improvements in this domain. By this time, he was an instructor at the University of Kentucky.
The "Elograph" was a screen but not transparent. However, it was a significant milestone in touch screen technology.
1974: first true touch screen incorporating a transparent surface came on the scene (still Sam Hurst)
1983: The HP-150: world's earliest commercial touchscreen computer.
Virtually all of the significant touchscreen technology were developed during the 1970s and 1980s.
columbia.edu

8. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion

9. Resistive
Technical explanation
Pros & cons
Applications

10. Resistive – Technical explanation
Composition of a resistive touch screen:
Composition :
Two flexible sheets coated with a resistive material and separated by an air gap and microdots.
Contact  2 sheets pressed record the location
Inconvenient of this method ? (next slide)

11. Resistive – Technical explanation
More detailed view of a resistive device:
4 reflecting surfaces, identified as S1 through S4
S1 and S4 each reflect 4% of the incident light
S2 and S3 each reflect around 5% of the incident light
S5 reflects about 2% of the incident light
Total reflectivity is around 20 %  It's clear that an LCD with an untreated resistive touch screen is unreadable in sunlight

12. Resistive – Pros & Cons Pros: Cons: Cheap Durable Bad clarity
According to you, what are the devices perfectly adapted to that technology ?

13. Resistive – Applications
Nintendo DS
PDA
Mobile Phone (i.e. HTC)
GPS
Touchpad

14. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion
Capacitif : iphone

15. Capacitive Technical explanation Pros & cons Applications
Capacitif : iphone

16. Capacitive – Technical explanation
Composition of capacitive touch screen:
A capacitive touch screen consists of a glass panel with a capacitive (charge storing) material coating its surface.
Describe the picture above

17. Capacitive – Technical explanation
The screen
Capacitive touch screens have front and back protective glass providing optical and strength enhancement options

18. Capacitive – Technical explanation
The screen
Its middle layer consists of a laminated sensor grid of micro-fine wires, and optical enhancement options

19. Capacitive – Technical explanation
The screen
During a touch, capacitance forms between the finger and the sensor grid. The embedded serial controller in the touchscreen calculates touch location coordinates and transmits them to the computer for processing.
Do you have an idea of the pros & cons ?

20. Capacitive – Pros & Cons
High touch resolution
High image clarity
Not affected by dirt, grease, moisture
Cons
Must be touched by finger, will not work with any non-conductive input
+ Thick glass  image clarity
+ Voltage drop  Not influenced by non conductive materials (not by dirt, grease and moisture)
Voltage drop  Won’t work with gloves for instance

21. Capacitive – Application
iPhone
Ticketing machine
Thick glass Almost unbreakable (in case of vandalism)
Ticketing machine :
Some research showed that women prefer HTC to Mac’s mobile phones because iPhone can’t be used with fingernails

22. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion

23. Surface acoustic Technical explanation Pros & cons Applications
Surface acoustic wave discovered in 1885 by Lord Rayleigh

24. Surface acoustic – Technical explanation
Wave through an elastic material
Generator, resistance measure
When the panel is touched, a portion of the wave is absorbed
change in the ultrasonic waves => position
Send information to controller
Wikipedia

25. Surface acoustic – Pros & Cons
Usable with everything
Perfect image
Cons
Fragile
Usable with everything (finger, glove, stylus)(avoid sharp objects)
Perfect image (100% transmission: ideal for detailed graphics)
Can be easily damaged by outside elements (dirt, scratch)

26. Surface acoustic – Application
Graphic design
Only there because only place where fragile not important and precision needed

27. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion

28. Strain gauge Technical explanation Pros & cons Applications
Strain gauge: Invented by Edward E. Simmons and Arthur C. Ruge in 1938
Once again, concept originally not used on screens.
Other uses: temperature (distortion with heat), mechanical (house starts to collapse)

29. Strain gauge – Technical explanation
Screen spring-mounted
Flexible resistance
The screen is spring-mounted on the four corners
CLIC!
Each gauge: flexible backing supports a metallic wire.
strain gauges => determine deflection (movement) when the screen is touched.
Force on 4 gauges => compute position of object
EXAMPLE: table (4 feet)
Wikipedia

30. Strain gauge – Pros & Cons
Z-axis measurement
Resistant
Movement
Usable with everything
Cons
Accuracy
Z-axis: drawing (Photoshop): pen wide or thin
Resistant: gauge durable

31. Strain gauge – Applications
Exposed public systems
Ticket-machines (Resistant to vandalism)

32. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion

33. Optical imaging
Technical explanation
Pros & cons
Applications

34. Optical imaging – Technical explanation
Composition of optical imaging touch screen:
A relatively-modern development in touchscreen technology
The light is emitted in a plane across the surface of the screen
At the heart of the system is a printed circuit controller board
The optical sensors track the movement of any object close to the surface by detecting the interruption of an infra-red light source

35. Optical imaging – Technical explanation
Composition of optical imaging touch screen:
A relatively-modern development in touchscreen technology
The light is emitted in a plane across the surface of the screen
At the heart of the system is a printed circuit controller board
The optical sensors track the movement of any object close to the surface by detecting the interruption of an infra-red light source

36. Optical imaging – Pros & Cons
No pressure is required
Provides multi-touch capability
Plug-and-play
Cons
Needs to be calibrate

37. Optical imaging – Applications
Military applications
Military because of its toughness
And many other kinds of applications

38. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion

39. Dispersive signal
Technical explanation
Pros & cons
Applications

40. Dispersive signal – Technical explanation
Sensors corners/backside of glass
Glass composed by substrate sensitive to vibration
CLIC: Generate vibrational energy
CLIC: Sensors get signal
Ask audience problem??? -> VIDEO
CLIC: Advanced dispersion adjustment algorithms are then applied to the data
CLIC: Subtract the reflected wave
3M.co.uk

41. Dispersive signal – Pros & Cons
Accurate
Object resting on screen ignored
Resistant
Usable with everything
Cons
A bit slow
No movement
Processing allow good accuracy
As palm of hand/object doesn’t generate vibrational energy => not detected => can put palm of hand on the screen
Ignores scratches (doesn’t generate energy)
Needs a lot of processing
When slide finger, not enough energy (vibration) detected

42. Dispersive signal – Applications
Exposed public systems
Long use purpose
Resistant
Long use: Possibility to put palm of hand on screen (Gorilla arm)

43. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion

44. Acoustic pulse recognition (APR)
Technical explanation
Pros & cons
Applications

45. APR – Technical explanation
Composition of a APR screen:
Acoustic Pulse Recognition (APR) touchscreens use a completely new and unique way of sensing touches on a display
It’s only of a glass overlay mounted in front of the display, together with a small electronic controller board

46. APR – Technical explanation
Composition of a APR screen:
1 - This system uses four piezoelectric transducers
2 - The transducers are mounted on two diagonally opposite corners out of the visible area and connected via a flex cable to a controller card
3 - Transducers turn the mechanical energy of a touch (vibration) into an electronic signal.
3 - This signal is then converted into an audio file, and then compared to preexisting audio profile for every position on the screen

47. APR – Pros & Cons Pros Cons Plug-and-play
Works with gloves, fingernails
Resistant to water
Cons
Drag-and-drop doesn’t always work well
Cons : Since it uses the vibration creates by a pressure on the screen, the drag-and-drop won’t work

48. APR – Application Restaurants
Cons : Since it uses the vibration creates by a pressure on the screen, the drag-and-drop won’t work
ELO demo : (drag-and-drop) works well on video 

49. Outline Introduction Definition History Digital technologies:
Resistive
Capacitive
Surface acoustic
Strain gauge
Optical imaging
Dispersive signal
Acoustic pulse recognition
Conclusion

50. Conclusion Gorilla arm State-of-art Market projection
Main issue: Gorilla arm: human not used to hold arm in front of head -> Gorilla position
Working on multitouch: more interactive, multi-users (collaborative work)
With the influence of the multitouch interactivity, the touchscreen market for mobile devices is projected to produce US$5 billion in 2009.

51. Thank you! Questions?
Main issue: Gorilla arm: human not used to hold arm in front of head -> Gorilla position
Working on multitouch: more interactive, multi-users (collaborative work)
With the influence of the multitouch interactivity, the touchscreen market for mobile devices is projected to produce US$5 billion in 2009.