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Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014
Introduction
Display Measurements
Summary & Outlook
Overview
Some pictures etc. are
courtesy of the companies
named on the picture,
others from, e.g., SID, …
Displays (LCD, OLED, E-Paper)
3D, Touch, Systems & Interfaces
1
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 2 2
• Introduction
• Touch Screen Technologies
Overview
• Application Issues
• Summary
Some slides are from Touch
Screen tutorials given by
3M, Fujitsu, Walker Mobile &
Elo TouchSystems
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 3 3
Touch Screens
Why - because it is in for CE since 2007!
Touch is not only technology – it is also user interface driven !
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 4 4
Touch Screen Basics
Finger input:
- simple, no device required, multi touch (gestures)
- but low “resolution”
Sylus input:
- simple, high
resolution (> 50 ppi)
- stylus required
- SW for text input
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 5 5
Touch Screens
• Easies many HMI concepts by direct input (command buttons etc.)
• Mature technologies available
• Allows easy input incl. characters and graphics e.g. smartphone
• Space saving compared to keyboard and mouse
Why ?
• Rise in some application system costs
• Reduced ambient light performance of display
• Inadequate performance of text input via stylus (is also an additional item !)
• Often more time consuming than keyboard and mouse
Why not ?
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 7 7
Professional Touch Screen Applications • Point of sale (POS) in restaurants, hospitality, post offices, …
• ATMs
• Industrial/process control
• Medical equipment
• Office equipment like copiers
• Retail
• Automotive: navigation, diagnostic systems
• Kiosks: Point of information (POI), merchandising, tourism & museums,
digital photo printing stations, …
• Ticketing & vending incl. transportation
• Gaming, amusement, …
• Telecommunication
• Internet terminals
• Outdoor: Gas pumps, store window applications, …
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 8 8
Touch Screen Cost Share
About the same price as for LCD !
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 9
Touch about Half the Price of AMLCD @ NEW IPAD
iPad bill of materials (BOM; Source: IHS isuppli, March 2012)
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 10 10
• Introduction
• Touch Screen Technologies
Overview
• Application Issues
• Summary
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 11 11
Display CL* T
G
a
p
G
a
p
TC IF SW
System
Display data
Touch Screen System
Display
Cover lens
Touch
Add-on Touch (not to scale,
avoid air gaps)
Resistive,
IR, SAW, …
Gap
PCap PCap
“Sensor
on Cover”
Integrated Touch
PCap
“Sensor
on Cell”
In-Cell
“Sensor
in Cell”
… includes
- Touch sensor (T)
- Touch controller (TC), interface (IF)
- Software (SW: driver, OS, …)
- …
Different ways to integrate a touch:
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 12 12
Touch Technologies 1/2
Criteria: - Display size,
- Touch object,
- Integration, …
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 13 13
Touch Technologies 2/2
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 14 14
Touch Screen System
…includes
- Touch sensor
- Touch controller, interface
- Software (driver, OS, …)
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 16 16
Projected Capacitive (V)
IPHONE Hardware
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 17 17
Projected Capacitive Cost Share
APPLE IPHONE integration
3$
3$
Integration 10$
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 18 18
Capacitive Overview
(no multi-touch)
Only small changes of capacity
are forced by finger etc.
sophisticated touch controller
and algorithms needed
Mainstream
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 19 19
Projected Capacitive
IPHONE HMI Examples
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 20 20
Projected Capacitive
Principle: Electrical field changes due to influence of dielectric parameter
Push by smartphones & tablets (CE touch awareness)
Touch controller is mission critical
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 21 21
Projected Capacitive
Screen
Principle
• A specially structured multi-layer
ITO-film is fully laminated to a
glass substrate.
• By the specially structured electrodes
an electric field will be „projected“
through the glass substrate.
• This electric field changes due to the
influence of a touch element (finger).
The dielectric parameter will change
and the controller (mission critical) can
calculate the position of this change.
• The touch finger does not need to
be conductive !
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 22 22
P-Cap Touch Screen Board
- Touch controller (TC)
- Interface (IF)
- Software (SW: driver, OS, …)
- Resolution, …
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 23 23
P-Cap Touch Signal Processing
- Control sensor electrodes to generate raw data
Noise avoidance via multiple techniques: Frequency Shifting, CDM, etc…
- Process data to convert to image data
- Derive and report data about finger touches (position, width, gestures)
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 24 24
• High resolution
• Multi-touch
• Fast response
• Good with finger, light touch
• Reliable & durable (protected sensor)
• High optical quality (plain glass)
• Unaffected by surface debris or contamination
Benefits
• Expensive
• Touch controllers are complex
• Stylus and gloves result in limited or no function
• Some EMI susceptibility
Issues
Projected Capacitive
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 25 25
Analog Resistive
Leading technology
until ~ 2009.
Reason: APPLE‟s IPHONE
with multi touch and
superb ambient
light capabilities.
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 26 26
Analog Resistive
Principle
‚Short„
To touch
controller
4, 5 & 8 wire technology
Air gap poor ambient light performance Touch screen board also needed
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 27 27
Analog Resistive (III)
Spacer
visible
In-flight entertainment system
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 28 28
Analog Resistive (IV)
x
y
2
1
R
Rx
4
3
R
Ry
‚Calculation„ of touch impact position
Multi touch ???
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 29 29
Resistive Touch Screen Board
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 30 30
Analog Resistive
• Wide-spread technology
• Low cost
• High resolution
• Insensitive to EMI
• No special equipment necessary, good with finger, glove, …
• Highly resistant to screen contaminates
• Sealability
• Low power consumption
Benefits
• No multi-touch (except for some special solutions)
• Relative high touch force
• Poor optical transmission (performance)
• Poor durability
Issues
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 32 32
Comparison
Technology Multi-
touch Resolution
Form factor
(bezel) Cost
Resistive No 100+ dpi,
any object ~ 5mm Low
Projected
Capacitive Yes
10 dpi - only
works with a
human finger
~ 1mm High
- All touch screens reduce clarity and enhance reflectivity of the display
- All touch screens rise power consumption:
LCD – Backlight or emissive luminance must be enhanced
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 33
Mobile Infrared Touch
Source: Walker, public and private
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 34
LCD In-Cell
• Visible in-cell sensor development stopped in industry
• IR- in-cell difficult to manage due to ambient IR
• In-cell pressure capacitive in SAMSUNG digital camera
but no cover glass possible (not a good idea)
• In-cell self capacitance touch not feasible due to cover glass
In-cell touch approaches show limited potential
Source: Walker, public and private
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 35 35
In-Cell Touch
In-cell light sensors
capture position like
a flat camera
Multi touch !
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 36
Source: Mackey, Synaptics
In - Cell Touch
There are rumors about in-cell touch
display from SHARP for IPHONE V
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 37 37
Camera Based
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 38 38
Radar Touch
• Excellent for large sized screens
• Gesture OK
• Lacks of multi touch by
geometric blocking
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 39 39
• Introduction
• Touch Screen Technologies
Overview
• Application Issues
• Summary
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 40 40
Touch Screens & System • Total cost of ownership: Consider initial purchase price plus long-term
costs including operation and maintenance
• Accepted input devices
Is it important that the application work with a finger, a gloved finger, a
metal stylus, a nonconductive stylus, a credit card, and/or a long fingernail?
• Durability: How harsh is the intended environment?
Will the system be used in the public sector (vandal considerations)?
• Image quality of the underlying display: Are clarity, brightness and
readability of the display important to the application?
• Sealability and chemical resistance: Is the screen/device likely to be
subjected to spills and/or cleaning with harsh chemicals?
• Reliability: What is the impact of any downtime for repair?
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 41
Touch Tasks
Acquire
• Touch position
• Number of touches (fingers)
• Gestures, …
Screen
“here”
Equipment etc. needed:
• Software to visualize GUI etc
and outputs (to e.g. file) touch
parameters like co-ordinates
• High speed camera for touch
events lag measurements or
equipment similar to response
time measurements
• Touch objects
• …
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 42
Touch TOUCH POSITION ACCURACY
• Simple test for controls etc.
• 5 or more point can be used,
“same” as uniformity
• Touch co-ordinates should
be located in the center of the
circles
• Use software which shows
buttons, circles, … and outputs
the touch co-ordinates X/Y
• To be judged: Co-ordinate in the
center of control if touched there
Source: IDMS
W/2
H/2
H/10
W/10 W/4 ; H/4
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 43
Touch LINEAR ACCURACY
• Deviations from straight line,
usually 4
• Move touch object along ruler
• Use “normal” speed
• Software stores touch co-ordinates
• Report on deviations:
- Average deviation (difference)
- Maximum difference
• To be defined:
Acceptable deviations
W/2
H/2
Reference
by ruler
Linear regression (tendency)
Acquired
Average
deviation
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 44
Touch REACTION TIME: LATENCY OF A SINGLE TOUCH
• Measure how fast the whole system reacts on a touch event
• This duration is influenced by many parameters like
response time of touch, touch signal processing, touch interface,
operating system response time, …
Source: IDMS
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 45
Touch REACTION TIME: LATENCY OF A LATERAL MOTION
• Measure the latency time between the input and the system reaction
• Similar measurement: Fastest movement of touch object without noticeable
latency between touch position and system reaction like curve
• This time is influenced by many parameters like response time of touch,
touch signal processing, touch interface, operating system response time, …
Source: IDMS
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 46
Touch Evaluation Summary
• Typical touch measurements are:
- Position
- Number of touch objects
- Accuracy of lines
- Speed
• There are a lot more like sensitivity to touch objects (like gloves),
cover lens thickness, dust and dirt on touch screen
• Especially “speed” (and gesture) strongly depends on system
reaction time where touch screen parameters are only a few
among many influencing topics.
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 47 47
Touch Screens & Ambient Light
Optical bonding !
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 48 48
Touch Issues
• Touch can damage the screen by pressure (e.g. LCD spacer)
• LCD touch can result in (temporal) image degradation (picture)
• Touch hinds objects on screen large buttons
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 49
Fingerprints
Source: DAIKIN
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 50 50
Touch Screen Overview (selected technologies and topics)
Resistive Capacitive IR
(e-reader) In - Cell
Multi touch - ++ + ++
Outdoor appl. - + + ++
Touch object ++ - + ++
Flush surface + ++ - ++
Integration Add on Add on,
in-cell Add on
Panel
maker
Size < 10” ++ ++ + ++
10” … 30” + + ++ ++
> 30” o o ++ ++
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 52
Touch Technology Comparison
Source: M. Jones
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 56 56
• Introduction
• Touch Screen Technologies
Overview
• Application Issues
• Summary
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 57
Interaction Approaches Beside Touch, Mouse, Keyboard
Source: Display Search 2012
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 59 59
Stylus & “Mouse over”
Source: Walker Mobile
SID 2012
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014
From Touch to 3D Gesture and Position
60
How many alarm clocks are falling down
each morning because a “touch” is
required to stop alarm sound ?
Touchless gestures are more suitable
but only a well-defined gesture reduces
“failures” e.g. “stop” vs. “snooze”.
Touchless would increase
safety while controlling
sliding sunroof as no
“touch” at a certain position (button) is required.
Sources: MICROCHIP
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014
Comparison Touch Touchless
Resistive PCap Camera Optical Cap
Easy of use easy easy difficult easy easy
Functionality low high medium medium medium
Position detection high high low medium medium
Multi touch no yes 2 hands no no
Gestures basic advanced advanced basic advanced
HW requirement low medium high medium low
Implementation simple challenging challenging medium simple
Power consumption low low high medium low
61
Human Machine Interaction Approaches H
e
r
e
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014
MICROCHIP GestIC for “Touchless Touch” & 3D Gestures
62
MICROCHIP GestIC
µC, gesture visualization
GestIC
Electrodes
and connections
LCD with driver
Applications:
- Touchless 3D control
- Wake up on approach
Merits:
Hygienic, no contamination, even for
simple devices without a display
K. Blankenbach, A. Delovski: Novel Gesture and Touch System with Transparent and
Curved Electrodes Enables New Computer-Human Interactions, International Conf-
erence on Advances in Computer-Human Interactions (ACHI 2014), Barcelona, 3/2014
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014
Touchless Application: Shopping Windows
63
• (Optical) camera may cause fear of being captured in “crazy clips” in internet!
• (Optical) camera has often difficulties dealing with all lighting situations.
• Camera systems are expensive in complex to integrate.
3D gesture with low cost transparent electrodes will overcome these issues
however electrode size has to be increased or “small operating pad”.
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 65 65
Summary
• Touch screens have many advantages like HMI
• Mature technologies available
• Integration needs some expertise incl. ambient light
• Not every touch technology is suitable for dedicated applications
Touch has many benefits
but need some system considerations
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 66
Case Study: Outdoor Kiosk
Topic Requirement PCAP Resistive
Size
Touch object
Multi touch
Ambient light
Vandalism proof
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 67 67
Summary
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 68 68
What Touch Screen Technology Is It ? (I)
• If it responds, it‟s either infrared or optical
- Resistive needs pressure
- Surface & projected capacitive need a finger
- Surface acoustic wave needs a sound-absorbing contact
- APR/DST (bending wave) needs a firmer touch
• Block the corners of the screen with something opaque
- If it still responds to a touch away from the corners, it‟s infrared
(IR transceivers are distributed all around the periphery)
- If it stops responding, it‟s optical
(imaging cameras are located in the corners)
Brush the screen very lightly with Kleenex
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 69 69
What Touch Screen Technology Is It ? (II)
• If it didn‟t respond, poke it with a toothpick
- If it responds, it‟s resistive or APR/DST (bending wave)
- Surface & projected capacitive need a finger
- Surface acoustic wave needs a sound-absorbing contact
- Check to see if the surface moves ever so slightly when you
poke it with the toothpick (watch a reflection of a light source
on the surface of the screen and try several locations)
- If the surface moves, it‟s resistive (the surface is PET)
- If the surface doesn‟t move, it‟s APR/DST (bending wave)
the surface is glass
Brush the screen very lightly with Kleenex
Multimedia Displays M S E I
Blankenbach / www.displaylabor.de / Touch / SS 2014 70 70
What Touch Screen Technology Is It ? (III)
If it didn‟t respond, touch it with a pencil eraser
- If it responds, it‟s surface acoustic wave
- Surface acoustic wave needs a sound-absorbing contact
- If it doesn‟t respond, it‟s either surface or projected capacitive
- Surface capacitive and projected-capacitive need a finger
- Check for faintly visible straight or jagged lines in a repeating
pattern in the darkest areas of the screen (the lines are most
visible when the screen is powered off and you‟re looking at
the surface using reflected light)
- If you see lines, it‟s projected capacitive
(you‟re seeing the transparent conductors on the sensor)
- If you don‟t see any lines, it‟s surface capacitive
Brush the screen very lightly with Kleenex