Fundamentals of Touch Technologies and Applications

Transcription

Fundamentals of
Touch Technologies
and Applications
Geoff Walker
NextWindow
Abbie Gregg
AGI
July 14, 2010
(at SEMICON West)
v1.0
Agenda: Part 1
 Admin [6]
 Introduction [7]
 Materials & Process 1: Basics [11]
 Touch Technologies with Continuous ITO
 Analog Resistive [7]
 Surface Capacitive [6]
 Materials & Process 2: Touch Screen Flow & Sputtering [15]
 Multi-Touch [9]
 Touch Technologies with Patterned ITO
 Analog Multi-Touch Resistive (AMR) [8]
 Projected Capacitive [11]
 Materials & Process 3: Common Processes [18]
 Embedded (On-Cell & In-Cell) [17]
 Materials & Process 4: Photolithography [18]
[ ] = Number of content slides in each section
2
Agenda: Part 2
 Touch Technologies Without ITO
 Acoustic Pulse Recognition (APR by Elo) [4]
 Dispersive Signal Technology (DST by 3M) [4]
 Materials & Process 5: Etch [13]
 Surface Acoustic Wave (SAW) [6]
 Traditional Infrared (IR) [4]
 Waveguide Infrared (by RPO) [5]
 Materials & Process 6: Embedded Touch [21]
 Optical [4]
 Force Sensing [4]
 Vision-Based [5]
 Comparing Touch Technologies [5]
 Conclusions [2]
[Total = 210]
3
Agenda: Appendix
 1 – Why There Are So Many Touch Technologies [6]
 2 – Electromagnetic Resonance (EMR) Pen Digitizer [4]
 3 – Flexible Displays and Touch [4]
 4 – ITO Replacement Materials [6]
 5 – Sunlight Readability of Resistive Touchscreens [9]
 6 – Automotive Touch [4]
 7 – Touch-Screen Manufacturing [31]
[ ] = 64 Total
4
About NextWindow
 NextWindow
 Develops & manufactures optical touchscreens
 Currently focused on two touch-screen markets


Windows-7 consumer monitors and all-in-one computers
Large-format display applications such as interactive digital signage
 Global presence



New Zealand (HQ), Singapore (Ops), USA, Taiwan, Korea, Japan
Manufacturing in China, Thailand and Malaysia
119 employees, 55 in engineering
 Brief history







2000: Founded by CTO and private investors
2003: First product to market (optical touch for large displays)
2005: Entered USA market
2006: First major volume contract signed (HP TouchSmart AiO)
2008: Entered Taiwan market with ODM focus
2009: Engaged with many PC OEMs & ODMs on Win-7 products
2010: Acquired by SMART Technologies
5
About Abbie Gregg, Inc.
• AGI provides facility, process,
industrial, and operations
consulting engineering and
design services
• Industries served
• Microelectronics
• Semiconductor
• Flat-Panel Display
• Flexible Electronics
• Touch Screens
• Photovoltaics
• Disk Drive
• MEMS
• Nanotechnology
• Biotechnology
• Medical
6
AGI Background
• Started in 1985
• Based in Phoenix, AZ
• 650+ projects
completed in North
America, Europe,
Asia, the Middle East
and Australia
• 40+ FPD, flexible
electronics and touch
projects completed
7
Introduction
Source: Elo TouchSystems
8
Two Basic Categories of Touch
 Opaque touch
 Dominated by the controller chip suppliers



Atmel, Cypress, Synaptics, etc.
One technology (projected capacitive)
Sensor is typically developed by the device OEM
 Notebook touchpads are the highest-revenue application


Synaptics ~60% share; Alps ~30% share; Elan ~10% share
Sensors are all two-layer projected capacitive
 There is no further discussion of opaque touch in this course
 Transparent touch on top of a display
 Dominated by the sensor manufacturers (100+ worldwide)
 13 technologies
9
2009 Touchscreen Market by
Size and Type of Technology
2009
Small-Med (<10”)
Revenue Units
Resistive
$1,707M
432M
Projected Capacitive
$1,479M
144M
Surface Capacitive
$8.2M
0.1M
Acoustic (SAW & BW)
$0M
0M
Infrared
$1.1M
0M
Mainstream $3,195M
577M
Emerging
$29M
3.0M
TOTAL $3,224M
580M
Technology
Revenue
Small-Medium
74%
Large-Area
26%
TOTAL
100%
Units
95%
5%
100%
Large-Area (>10”)
Revenue Units
$379M
19M
$55M
1.0M
$210M
2.1M
$149M
1.9M
$63M
0.5M
$856M
25M
$255M
2.6M
$1,110M
27M
TOTAL
Revenue Units
$2,085M
452M
$1,534M
145M
$218M
2.2M
$149M
1.9M
$65M
0.6M
$4,051M
601M
$284M
5.6M
$4,334M
607M
Revenue
Mainstream
93%
Emerging
7%
TOTAL
100%
Units
99%
1%
100%
Market size estimates are based on DisplaySearch’s “2010 Touch-Panel Market Analysis Report” (June 2010)
10
2009 Touchscreen Market
by Technology
Technology
Analog Resistive (all forms)
Surface Capacitive
Acoustic (SAW, APR & DST)
Optical (including vision-based)
Digitizer
Infrared (all forms)
LCD In-Cell & On-Cell (all forms)
Others
TOTAL
2009
Revenue
2009
Share
$2,085M
$1,534M
$218M
$149M
$134M
$123M
$65M
$25M
$1M
$4,334M
48%
35%
5.0%
3.4%
3.1%
2.8%
1.5%
0.6%
0%
100%
2009
Units
452M
145M
2.2M
1.9M
1.1M
1.5M
0.6M
2.9M
0M
607M
2009
Share
74%
24%
0.4%
0.3%
0.2%
0.3%
0.1%
0.5%
0%
100%
Market size estimates are based on DisplaySearch’s “2010 Touch-Panel Market Analysis Report” (June 2010)
11
Millions
Touch Market Forecast 2010-2016
$16
DisplaySearch 2010 Touch Market Analysis
$14
Revenue ($B)
$12
In-Cell
Others
On-Cell
Infrared
Digitizer
Optical Imaging
Acoustic
Surface Capacitive
Resistive
$10
$8
$6
$4
$2
$0
2009
2010
2011
2012
2013
2014
2015
2016
12
M = Mainstream
Large-Format
( >30”)
Analog Resistive
Analog Multi-Touch Resistive (AMR)
Surface Acoustic Wave (SAW)
Traditional Infrared (IR)
Waveguide Infrared (from RPO)
Surface Capacitive
Projected Capacitive (ITO & on-cell) (P-cap)
Projected Capacitive (wires on film) (P-cap)
Optical
Acoustic Pulse Recognition (APR from Elo)
Dispersive Signal Touch (DST from 3M)
Embedded (in-cell)
Vision-Based (like Microsoft Surface)
Force Sensing (no current supplier)
Stationary
Consumer
(17” – 30”)
Touch Technology
Stationary
Enterprise
(10” – 30”)
Mobile
(2” – 17”)
Touch Technologies
by Size & Application
M
L
E
E
E
L
M
M
E
M
M
E
M
M
E
L
E
M
E
L
L
M
L
L
E
L = Low-volume
E
E = Emerging
13
Touch Is An Indirect Measurement
One Reason Why There Are So Many Technologies…
Touch Technology
Resistive (all forms) &
Embedded (voltage)
Surface capacitive
Surface acoustic wave
Projected capacitive,
Embedded (charge)
Optical & Infrared (all forms),
Embedded (light) in high ambient
Embedded (light) in low ambient
Vision-based
Acoustic Pulse Recognition (APR) &
Dispersive Signal Technology (DST)
Force sensing
What’s Being Measured
Voltage
Current
Time delay
Change in capacitance
Absence of light
Presence of light
Image
Bending waves
Force
The ideal method of detecting touch
has yet to be invented!
14
Touch Technologies
by Materials & Process
Touch Technology
Transparent
Conductor (ITO)
Continuous
No Transparent
Conductor
Patterned
Analog resistive
Surface capacitive
Low
Resolution
High
Resolution
Analog
multi-touch
resistive
(AMR)
Projected
capacitive
Embedded
(In-cell &
on-cell)
Edge Conductors
No Edge
Conductors
Acoustic Pulse
Recognition (APR)
Dispersive Signal
Technology (DST)
Traditional infrared (IR)
Waveguide infrared
Surface acoustic wave (SAW)
Optical
Force sensing
Vision-based
= Mainstream
= Emerging
15
Materials & Process…1
Basics
16
Materials and Processes
Conductors, Insulators, Semiconductors
17
• Conductors
• A conductor is a material which can conduct or pass electric
current and heat easily
• Copper is a good conductor, wood is not
• Conductors transport a signal from one part of the circuit to
another
•
Example: Metal interconnect
18
• Insulators
• An Insulator is a material which cannot conduct or pass electric
current or heat easily
• Wood and glass are good Insulators
• Insulators block the transmission of current
•
Example: Oxide (SiO2)
19
• Conductors and Insulators
•
Place a wooden spoon and a copper spoon in a pot of boiling
water for 5 minutes
•
Now take the spoons out of the water
•
Which one is a conductor?
Ouch!
•
Which one is an insulator?
Ahh....
20
• Semiconductors
• Semiconductors have the ability to conduct electric current, but
can be regulated in the amount of their conductivity
21
• Conductors
• Very large current flows
• Semiconductors
• Some current flows
• Can be regulated
• Insulators
• Very small current flows
22
Materials: Elements
Everything in the world is made up of elements
23
Materials: Elements
A portion of the Periodic Table is shown below
Transparent Conductors:
• ITO = Indium Tin Oxide
• ATO = Antimony Tin Oxide
Groups: I
II III
H
Li Be B
Elemental
Na Mg Al
Semiconductors
(Tin)
Ga
In
P – Type Dopants
(Indium)
Oxygen
IV
V
VI
VII VIII
He
F
Ne
Cl Ar
C
Si
Ge
Sn
Pb
N O
P S
As
Sb
N – Type Dopants
(Antimony)
24
Devices Used in Touch Technology
Resistors
a
a
Metal / Conductor
b
R
Units =
Ohms
b
Capacitors
• Store Charge
a
Conductor
Insulator
Conductor
Oxide
a
C
Substrate
b
Units =
Farads
b
25
Cleanliness Considerations
In Touch Screen Manufacturing
• A Human Hair = 70 microns
• Smallest thing visible with the naked eye = 30 microns
• 1µ = 1 micron = 1 millionth of a meter
• 1nm = 1 nanometer = 0.001 microns = 1 billionth of a meter
• 1 angstrom = 0.1 nanometer = 10E-10 meter
• Something “invisible” can destroy a device!
• Touch device geometries = 5 to 300 microns
•
ITO Film Thickness < 1 micron
• TFT geometries = 1 to 5 microns
• Integrated Circuit geometries = 28nm to 3 microns
• Touch devices typically made of only 7 to 11 materials, which
have special electrical or optical properties!
• ANY OTHER substance will ruin a device!
26
Airborne Particulate Cleanliness Classes
ISO 14644-1 Cleanroom Standards
Clean spaces are classified according to Federal Standard
209E and ISO 14-6444. Air cleanliness is defined by the
number of airborne particles 0.5mm and larger per cubic
foot of air. These standards also define the concentration
limits of larger and smaller particles in air such as:
Large volumes of air are circulated within
the clean spaces to process the air to
required limits. Complexity and cost
increase for more stringent conditions
required by higher quality classes. The
operating cost also reflects the highenergy consumption necessary to
condition and move large volumes of air.
Class 10
ISO 4 Maximum 350 particles of 0.1mm and
no more than 75 particle of 0.2mm and
10 particles of 0.5mm per cubic foot.
Class 100
ISO 5 Maximum 750 particles of 0.2mm and
no more than 100 particles of 0.5mm
per cubic foot.
Class
Class 1000
ISO 6 Maximum 1,000 particles of 0.5mm
and no more than 7 particles of 5mm
per cubic foot.
Class 10,000
ISO 7 Maximum 10,000 particles of 0.5mm
and no more than 70 particles of 5mm
per cubic foot.
100,000
10,000
1,000
100
Class 100,000 ISO 8 Maximum 10,000 particles of 0.5mm
and no more than 700 particles of
5mm per cubic foot.
Air Flow
Direction
CFM/SF of
Floor (room
5-8
9-15
15-50
50-80
Acceptable
Air
Changes
Per Hour
5-45
60-80
150-240
240-480
80-100
520
90-110
600
velocity
fpm)
10
1
Mixed
Mixed
Mixed
UniDirectional
UniDirectional
UniDirectional
27
Particles / Cubic Foot (Stated Size)
Particle Density vs. Cleanliness Class
CL
10,000
CL
1,000
100
AS
S
AS
S
CL
10
10
00
10
0
AS
CL
S
AS
1
S
Acceptable particle count for Class 100
10
1
0.1
0.1
1
1 MEG
DRAM
0.2
2
256K
DRAM
0.5
5
1
2
5
10
10
20
50
100
Particle Size (micron)
64K
16K
Assembly Hybrids PC Boards
DRAM
DRAM
IC's
LCD
In Cell Touch
Critical Particle Size
Typical Geometry Size
Typical Devices
Touch
28
Touch Technologies
with Continuous ITO
 Analog Resistive
 Surface Capacitive
 (Materials & Process 2:
Touch-Screen Flow & Sputtering)
29
Analog
Resistive
Source: Engadget
30
Analog Resistive…1
(ITO)
(PET)
Source: Bergquist
31
 Types
 4-wire (low cost, short life) is common in mobile devices
 5-wire (higher cost, long life) is common in stationary devices
 Constructions
 Film (PET) + glass (previous illustration) is the most common
 Film + film (used in some cellphones) can be made flexible
 Glass + glass is the most durable; automotive is the primary use
 Film + film + glass, others…
 Options
 Surface treatments (AG, AR, AS),
rugged substrate, dual-force touch,
high-transmissivity, surface armoring,
many others…
(50-uM glass) Source: Schott
32
4-Wire Construction
Equivalent circuit
X-Axis
Voltage
gradient
applied
across
glass
Voltage
measured on
coversheet
Voltage
gradient
applied
across
coversheet
Bus
bar
Voltage
measured
on glass
Y-Axis
33
5-Wire Construction
X-Axis
Voltage
gradient
applied
across
glass
Equivalent circuit
Voltage
gradient
applied
across
glass
Contact point
on coversheet is
a voltage probe
Contact point
on coversheet is
a voltage probe
Linearization
pattern
Y-Axis
34
 Size range
 1” to ~24” (>20” is rare)
 Controllers
 Many sources
 Single chip, embedded in chipset/CPU,
or “universal” controller board
 Advantages






Source: Liyitec
Works with finger, stylus or any non-sharp object
Lowest-cost touch technology
Widely available (it’s a commodity)
Easily sealable to IP65 or NEMA-4
Resistant to screen contaminants
Low power consumption
Source: Hampshire
35
 Disadvantages
 Not durable (PET top surface is easily damaged)
 Poor optical quality (10%-20% light loss)
 No multi-touch
 Applications
 Mobile devices
 Point of sale (POS) terminals
 Wherever cost is #1
 Market share
2009
Revenue
48%
Volume
74%
36
 Suppliers
 Nissha, Young Fast, J-Touch, Gunze, Truly Semi, Fujitsu,
EELY, Elo TouchSystems, SMK, Swenc/TPO, eTurboTouch…
 60+ suppliers
 Market trends
 Analog resistive is losing share (1st time!) to projected capacitive
in the mobile market

First significant challenge to analog resistive’s dominance
 Analog resistive is still very important in mobile phones in Asia

It supports a stylus; projected capacitive doesn’t (yet!)
37
Surface
Capacitive
Source: 3M
38
Surface Capacitive…1
Tail
Scratch-resistant
top coat
Hard coat with AG
Electrode pattern
Conductive coating
(ATO, ITO or TO)
Glass
Optional bottom
shield (not shown)
Source: 3M
39
 Variations
 Rugged substrate
 Size range
 6.4” to 32”
 Controllers
 3M, Hampshire, eGalax,
Digitech and Billabs (ISI)
 Advantages




Source: 3M
Excellent drag performance with extremely smooth surface
Much more durable than analog resistive
Resistant to contamination
Highly sensitive
Source: Billabs
40
 Disadvantages




Finger-only
Calibration drift
Susceptible to EMI (no mobile use)
Moderate optical quality
(85% - 90% transmissivity)
 Applications
 Regulated (casino) gaming
 Kiosks
 ATMs
 Market share
2009
Revenue
5%
Volume
<1%
Source: 3M
41
 Suppliers
 3M, DanoTech, Elo TouchSystems, EELY, DigiTech, eTurbo,
Optera, Touch International, Higgstec…
 16+ suppliers (dominated by 3M)
 Market trends
 Surface capacitive isn’t growing with the touch market


No multi-touch capability; other significant disadvantages
Casinos (major market) are starting to experiment with
other touch technologies
 Price is dropping as Taiwanese and Chinese suppliers
enter the market now that 3M’s key patent has expired
42
A New Spin: Wacom’s RRFC
Surface Capacitive Technology

 How it works
 AC voltage on 2 adjacent corners;
DC voltage on other 2 corners

Creates ramp-shaped electrostatic field
across surface
 Controller switches signals around all
4 corners, creating 4 ramp fields vs.
single flat field in standard capacitive

Current flow is measured in each case
 Resulting signal representing touch
event is independent of all capacitance
effects except those due to finger touch
 Controller does additional digital signal
processing to compensate for factors
that affect accuracy and drift
Source: Wacom
(Trademark = CapPLUS)
 RRFC = Reversing Ramped
Field Capacitive
43
Wacom’s RRFC Technology…2
 Advantages
 Solves all the problems of traditional surface capacitive





Works in mobile & stationary devices (10” to 32” now; 3” to 46” soon)
Unaffected by grounding changes, EMI, variations in skin dryness
& finger size, temperature, humidity, metal bezels, etc.
Works through latex or polypropylene gloves
Allows 4X thicker hardcoat for improved durability
Screen works outdoors in rain and snow
 Uses same ASIC as Wacom’s EMR pen digitizer, so dual-mode
input is lower cost & more efficient (e.g., in Tablet PC)
 Disadvantages
 No multi-touch
 Sole-source supplier
44
Touch Screen Flow
& Sputtering
45
Processes
• Flex and glass touch
screen sample product
flow charts
• In-depth look at
sputtering process
module
Photo: NextWindow
46
Sample Touch Screen Flow Chart 1
Web Process – Bottom Substrate
47
Web Process – Top Layer
48
Sheet Processing – Spacer
49
Die Cutting & Prep and Assembly of Flex Layers to Glass
Die Cutting
Prep and Assembly of Flex
Layers to Glass
50
Pre Process and
Clean Sheets
Glass Plate Cleaning
51
Sample Touch Screen Flow Chart 2A
52
Sample Touch Screen Flow Chart 2B
53
Blanket Conductive Films
Process Methods – Sputter Process Module
Basic steps are used for Thin Film Deposition:
• Inspect substrate
• Clean substrate (optional)
• Deposit film
• Measure film
• Resistivity
• Thickness
54
Thin Film Deposition Processes
• CVD – Chemical Vapor
Deposition
• Sputtering
•
•
•
Lower Thermal Budget
Targets are pure
materials
Dopant gases can be
used (e.g. O2 for ITO)
• Evaporation
•
•
Higher Thermal Budget –
too hot for Flex
Sources are pure
materials
• PVD – Physical Vapor
Deposition
• PVD used for metals:
•
•
•
•
•
•
•
•
Aluminum & Alloys
Gold
Platinum
Titanium Tungsten
Indium Tin Oxide – Touch
Molybdenum
Moly Tantalum
Chrome
55
Simple Sputtering System
Independent Variables
•Target Composition
•Target Spacing
•Power
•Time
•Vacuum
•Temperature
•Gas Flow
Oxygen (optional)
Dependent Variables
•Composition
•Thickness
•Resistivity
•Uniformity
•Defect Density
•Adhesion of Film to
Substrate
56
How Can Defects Happen In PVD?
DEFECT
IN FILM
SUBSTRATE
particle
SUBSTRATE
BEFORE PROCESS
AFTER FURTHER
PROCESSING
DEFECT
IN PVD FILM
SUBSTRATE
AFTER PVD
57
Sputterer – FPD Scale
Rigid Substrates
Clean
load
areas
Class 10
Load
ports
Substrate
storage
and
handling
Target
Vacuum
pumps
58
Large-Scale Roll-to-Roll Sputtering
on Flexible Substrates
Large, clean metalization system.
Photo courtesy of Konarka
Photos courtesy of
Hanita Coatings
59
Roll-to-Roll Process Lines, Coating & Laminating
ITO and Other Transparent or Opaque Conductors
Exhaust for
reactive
processes
Use of
vertical
space
Clean minienvironment
Roll staging
Computer control
Photo courtesy
of Hanita Coatings
60
Scale of Operations and Geography
1. Flex on large sheets (500 x 500 or so) requires
demand of 0.3 to 1 million per month for small
devices
2. Roll-to-roll scale-ups require volume over 5 million
per month for small devices, 1 million per month for
large
1. Automated large size webs, 48 to 54 inches wide by 5,000 or
more feet long
61
Multi-Touch
2  4  10
Sources: Engadget, Do Device
and Good Times & Happy Days
62
Multi-Touch
 Multi-touch is defined as the ability to recognize
two or more simultaneous touch points
 Multi-touch was invented in 1982 at the
University of Toronto (not by Apple in 2007!)
 “Pinching” gestures were first defined in 1983
(not by Apple in 2007!)
 Windows 7 (released 10/22/09) supports multi-touch
throughout the OS
 Windows 7 is structured to support an “unlimited”
number (~100) of simultaneous touch points
63
Multi-Touch Architecture
Application
Capable of decoding multiple
streams of moving points and
taking actions in response
Operating System
Capable of forwarding multiple
streams of moving points (and
acting on a defined subset of them)
Touchscreen
Controller & Driver
Capable of delivering sets of
simultaneous points to the OS
Touchscreen Sensor
Capable of sensing multiple
simultaneous points
64
Multi-Touch Technologies
Touch Technology
Analog Multi-Touch
Resistive (AMR)
LCD In/On-Cell (all forms)
Vision-Based
Optical
Surface Acoustic Wave
(Elo TouchSystems)
Waveguide Infrared
(RPO)
Traditional Infrared
Acoustic Pulse Recognition
(APR - Elo)
Bending Wave
(DST – 3M)
Analog Resistive
Surface Capacitive
Force Sensing
Multi-Touch
Capable? (#)
Yes (unlimited*)
Win-7 Logo
Capable?
Yes
Yes (unlimited*)
Yes
Yes (unlimited*)
Yes (unlimited*)
Yes (2)
Yes (2)
Yes
Yes
Yes
Yes
Yes (2)
Yes
Yes (2)
Future (2)
Yes
Maybe
Future (2)
Maybe
No
No
No
No
No
No
Commercial MT
Product Example
Apple iPhone;
Dell Latitude XT
JazzMutant
Music Controller
Samsung Camera
Microsoft Surface
HP TouchSmart
Lenovo A700
AiO PC
LG Display 13.3”
Notebook (SID)
Nexio 42” Monitor
Technology in
development (2010)
Technology in
development (2010?)
----
* Controller-dependent, not sensor-dependent
65
Windows-7 Logo
 A set of touch performance standards designed
to ensure a high-quality user experience















Test 1: Sampling Rate
Test 2: Single-Touch Taps in 4 Corners
Test 2: Single-Touch Taps in 5 Other Locations
Test 3: Single-Touch Press-and-Hold
Test 4: Double Taps
Test 5: Multi-Touch Points
Test 6: Press and Tap
Test 7: Straight-Line Accuracy
Test 8: Maximum Touch Lines
Test 9: Multi-Touch Straight Lines
Test 10: Line Accuracy Velocity
Test 11: Single-Touch Arcs
Test 12: Pivot
Test 13: Multi-Touch Arcs
Test 14: Ghost Point Test
66
What’s So Hard About Multi-Touch
with Analog-Type Sensors?
Keeping
the right X
with
the right Y
when going
through
occlusion
67
What’s So Hard About Multi-Touch
with Digital-Type Sensors?
Designing a
controller
that can put
out enough
points fast
enough
Source: Techdu.de
68
How Many Touches Are Enough?
 Why multi-touch will expand beyond two touches
 Most research on multi-touch is being done with vision-based
hardware because it’s easy to develop the hardware yourself

Vision-based touch supports an unlimited number of touches

All other multi-touch-capable technologies are difficult to build & buy
 Projected capacitive (currently the #2 touch technology!) also
supports an unlimited number of touches
 Number of touches is one way for a touch technology
vendor to differentiate themselves
 Recognizing and ignoring more than two touches
 ISVs are creative; they’ll find ways to use more touches (games)
(“If you build it, they will come”)
69
An Anomaly: Multi-Touch Gestures
on Non-Multi-Touch Screens
 Elo TouchSystems: “Resistive Gestures”
 Capable of sensing two-finger gestures on
standard analog resistive touch-screens
 Fingers must be moving to sense two
points; two static touches don’t work
 3M: “Multi-Touch Gestures on DST”
 Same capability & restriction as above on Dispersive Signal
Technology (DST) touch-screens
 It’s not true multi-touch, but is it good enough?
 Gestures are HOT, so device manufacturers want them
 Today, multi-touch is mostly used to enable two-finger gestures
 For mobile devices, pro-cap is ~3X the cost of analog resistive,
so enabling gestures on analog resistive is attractive
70
#1 Reference On Multi-Touch
 “Multi-Touch Systems that
I Have Known and Loved”
 www.billbuxton.com/multitouchOverview.html
“If you can only manipulate one
point … you are restricted to the
gestural vocabulary of a fruit fly.
We were given multiple limbs
for a reason. It is nice to be
able to take advantage of them.”
Bill Buxton, 2008
Principal Researcher,
Microsoft Research
71
Touch Technologies
with Patterned ITO
 Analog Multi-Touch Resistive (AMR)
 Projected Capacitive
 (Materials & Process 3: Common Processes)
 Embedded (In-Cell & On-Cell)
 (Materials & Process 4: Photolithography)
72
Analog
Multi-Touch
Resistive
(AMR)
73
Analog Multi-Touch Resistive…1
Segmented type (for vertical applications)
Opaque switch panel
(the original purpose
of digital resistive)
MultiTouch
Controller
Touch Sensor:
Single-Layer (shown)
or Two-Layer Matrix
Source: Apex
74
All Points Addressable (APA) type
(competes with projected capacitive)
Multi-Touch
Source: Wintek
75
 Two sub-types of All Points Addressable
 Each conductive intersection is treated as a digital switch;
it’s either on or off (should call it “Digital Multi-Touch Resistive)

Resolution = ½ the width of a conductive trace (0.7 mm typical)
 Each conductive strip is treated as
a digital “channel”; each intersection
is treated as a miniature 4-wire
touchscreen

Resolution = analog function
(0.2 mm optimum)
Source: J-Touch
76
“Digital” type
3.74” x 2.12”
(128 pixels/inch)
64 x 36 sensing lines
= 1.5 mm squares
= 4.8 pixels/square
Display and
digital resistive
sensor by Wintek;
controller by
Stantum
(SID 2009)
77
(Actual Product)
“Analog” type
21.5”
multi-touch
resistive by
eTurboTouch
28 x 17 lines
= 17 mm x
16 mm squares
(90 pins)
23” = 35 x 22 lines
15 mm x 13 mm
(114 pins)
78
 Types
 Segmented, for vertical-market applications
 All points addressable [APA], competes with pro-cap


Pure digital
Hybrid digital-analog
 Constructions
 PET + Glass, PET + PET, etc. (same as analog resistive)
 Options
 Technically same variety as analog resistive, but less demand
 Size range
 3” – 25”
79
 Controllers
 Single-touch – many sources
 Multi-touch


Stantum for digital type
?? for hybrid analog-digital type
 Unlimited multi-touch
 Simple, familiar technology
 Lower cost than pro-cap
 Disadvantages (mostly the
same as analog resistive)
100 x 128 connections!
Source: Stantum
 Advantages
 Poor durability (PET top surface)
 Poor optical performance
 More expensive than analog resistive
80
 Applications
** See US patent application 2007-0198926
 Mobile devices
 Multi-touch music controllers (JazzMutant/Stantum**)
 Market share
 Just starting
 Controller suppliers
 Many suppliers for single-touch,
but no standouts
 Stantum, AD Semi, J-Touch, Wintek
 Market trends
 Suppliers are gearing up to
compete against pro-cap
Source: Jazz Mutant
81
Projected
Capacitive
Source: Apple
82
Projected Capacitive…1
Why “Projected”?
Finger
 A finger “steals charge” from the X-electrode,
changing the capacitance between the electrodes
 Electric-field lines are “projected” beyond the touch
surface when a finger is present
83
MAX
“Perimeter scan” or “non-imaging” type (NB touchpad)
Finger
X-Scan
MAX
ITO transparent conductors
Y-Scan
 X-axis and
then Y-axis
electrodes
are scanned
sequentially,
looking for
point of
maximum
capacitance
to ground
 Ghost points
are a problem
with 2 touches
84
“Imaging” or “all points addressable” type (Apple iPhone)
 Output is
an array of
capacitance
values for
each X-Y
intersection
85
Raw data including noise
Gradient data
Filtered data
Touch region coordinates
and gradient data
Touch regions
“10 fingers,
2 palms
and
3 others”
Source: Apple Patent Application #2006/0097991
86
 Technology variations
 Single-layer sensor (no crossovers)


“Self capacitance”
Rarely used with displays due to low resolution
 Two-layer sensor (X-Y grid)

“Peripheral scan” or “non-imaging” (Synaptics ClearPad™)
 Not commonly used with displays due to limited number of touches

“All points addressable” or “imaging” or “mutual capacitance”
 Most common configuration
 Supports unlimited number of touches (controller-dependent)
87
 Sensor variations








Wires between two sheets of glass (Zytronic)
Wires between one piece of PET and one piece of glass (Zytronic)
Wires between two sheets of PET (Visual Planet)
ITO on two pieces of glass
ITO on both sides of one sheet of glass
ITO on two pieces of PET (Touch International)
ITO on one piece of PET and one piece of glass
ITO in two layers on one side of glass with dielectric (TPK)
 Wires vs. ITO
 Wires: Visible, acceptable for intermittent use
 ITO: Invisible, needed for continuous use
88
 Size range
 2” to 100”+

ITO up to 22”; wires up to 100”+
 Advantages






Very durable (protected sensor)
High optical quality (ITO)
Unlimited multi-touch
Unaffected by debris or contamination
Enables “zero-bezel” industrial design
Works with curved substrates (on PET)
 Disadvantages
 Finger or tethered pen only
 High cost (dropping as usage increases)
 Difficult to integrate due to noise sensitivity
LG-Prada mobile phone with Synaptics’
projected-capacitive touch-screen;
launched 3 months before iPhone
89
 Applications
 Consumer devices




Smartphones
Netbooks, notebooks, Tablet PCs
Apple AiOs (2010)
Almost any consumer device < 10”
 Vertical-market devices


Source: Mildex
Signature-capture & other POS terminals
“Through-glass” interactive retail signage
 Market share
2009
Revenue
35%
Volume
24%
Demy
Digital
Recipe
Reader
(CES 2010)
Source: Verifone
90
Gunze’s “Direct Printing Technology” (DPT)
for large-area capacitive touchscreens
(shown at SID 2009)





Flexible pro-cap sensor
Printed silver conductors, 0.5 ohm/sq.
Roll-to-roll, maximum size 50”
< 1 mm resolution
78% transmissivity with 20µ/300µ line/space
Source: Gunze
91
36 suppliers at end of 2009; 58 now
Pro-Cap Vendor
Altera
Analog Devices
Atmel (Quantum)/ST Micro
Avago
Broadcom
EETI (eGalax)
Focal Tech Systems
Melfas
Microchip Technology
Pixcir Microelectronics
RISIN Technology
Silicon Integrated Systems (SIS)
Texas Instruments
Alps
Cando (AUO)
Digitech
Emerging Display Technology
HannStar Display
Country
USA
USA
USA
USA
USA
Taiwan
China
Korea
USA
China
Taiwan
Taiwan
USA
Japan
Taiwan
Korea
Taiwan
Taiwan
Controller
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
China = 5
Israel = 1
Japan = 4
Korea = 2
Taiwan = 13
UK = 1
USA = 10
Sensor
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Pro-Cap Vendor
Innolux
iTouch Electro-Optical
J-Touch
Nissha Printing
Panasonic Electric Devices (PED)
Panjit (Mildex)
QuickTouch Technology
Sintek Photronic
Touch International
TPK
Wintek
Young Fast Optoelectronics
Cypress
Elan Microelectronics
N-trig
Synaptics
Wacom
Zytronic
Country
Taiwan
China
Taiwan
Japan
Japan
Taiwan
China
Taiwan
USA
China
Taiwan
Taiwan
USA
Taiwan
Israel
USA
Japan
UK
Controller
No
No
No
No
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Sensor
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Controller Only = 13
Sensor Only = 17
Controller & Sensor = 6
(“module”)
92
 Market trends
 Extremely strong worldwide interest
 Rapidly increasing number of suppliers (>250% in last year)
 Rapidly dropping prices (>50% in last 18 months)
 Upper size limit expanding from 8” to 22”
 OEMs’ desire for multi-touch is a key driving force,
along with durability and high optical performance
 The first significant challenge to analog resistive
in mobile devices
The
iPod
Touch
Source: Apple
93
Common Processes
94
• Glass washing
• Screen printing
• Lamination
• Wet etch
• Inspection
• Roll-to-roll
95
Spacer Layer
96
Glass Layer
97
Flex Layer
98
Final Assembly
99
Other Processes Used
In Touch Screen Manufacturing
• Sheets or rolls can be processed easily at the
following steps
–
–
–
–
–
–
Vacuum deposition (PVD)
Screen printing
Laminating
Punching
Picking and placing
Drying and curing
• Process sections with critical alignment and registration
will be most difficult
100
Patterning = Design Rules
Tolerance Explanation
• Clients design their products based
on an edge-to-edge tolerance
(generally of ±1% of component
dimensions). This can be expressed
by giving each component a
tolerance (generally of ±0.5% of
component dimension) relative to a
fixed reference point in a product.
The geometric centre of “S” has
been chosen as this reference
point. All other product layer
tolerances will reference this point.
Axis of web travel
S
x/2
y
y/2
Centre of S
x
• Any distortion will affect product
alignment
101
Glass Washer
• Input parameters
–
–
–
–
–
Water quantity
Water spray pattern
Drying technology
Cleanliness
Washing speed, drying
speed
• Output Parameters
– Cleanliness
– Throughput
Options
–
–
–
–
Zero consumption water savings system
“Flip-Top” hydraulic lift system
Pre-spray system
Static elimination system
102
Screen Printing Concept
• Screen printing is a printing technique
that uses a woven mesh to support an
ink-blocking stencil. The attached stencil
forms open areas of mesh that transfer
ink as a sharp-edged image onto a
substrate. A roller or squeegee is moved
across the screen stencil, forcing or
pumping ink past the threads of the
woven mesh in the open areas.
•
Input parameters
–
–
–
–
–
•
Squeegee space
Pressure
Stroke length
Material usage
Alignment
Output parameters
–
–
–
–
Film thickness
Film resistivity
Pattern defects
Contaminants
103
Production Screen Printers
• In screen-printing on touch devices, the mesh
and buses of silver are printed on the glass or
flex
• One of the parameters that can vary and can
be controlled in screen printing is the thickness
of the print
• This makes it useful for some of the
techniques of printing touch screens,
electronics etc.
104
Fully Automatic Screen Printing
• Aligns fiducial marks on the screen and
substrate with the use of two high-contrast
cameras to ensure accurate and repeatable
deposition for multilayer devices. All
processing variables (e.g., squeegee speed
and pressure) are monitored and dynamically
adjusted to ensure identical fabrication from
batch to batch.
• A fully automatic screen-printer is capable of
loading/unloading a substrate, aligning a
screen to it, and using feedback loops to
ensure uniform squeegee speed and
pressure as the machine pushes to-bedeposited materials through the mesh and
onto the substrate.
• Setting & monitoring of printing
parameters:
• Storage system of job
parameters
• Diagnostics of settings
• Variable stroke lengths of
squeegee & flood coater
• Adjustable gripper, squeegee &
flood coater speeds
• Motorized off-contact
adjustment.
105
Screen Printing for Touch Screens
• Pilot for automation may reveal new variables
• Operators may not support automation at first
106
Screen Printing and Drying
Half meter wide web, scale up of sheet
process, multiple lines
107
Curing and Drying
In Roll-Format Oven
• Engineered to have
high degree of control
and minimize space
108
Laminator
• Input parameters
–
–
–
–
Temperature
Time
Pressure
Alignment
• Output parameters
–
–
–
–
Adhesion
Flatness
Defects
Registration
109
Process Detail Needed for Lamination
• Lamination
– Position the y-substrate on a millimetric paper
– Clean with antistatic spray
– Laminate PSA to the y-substrate using an antistatic gun and a
laminating roller at Pressure A +/- a, temperature B+/-b
– Remove PSA residue around the substrate y using a sharp knife
– Position the film x to film y using positioning aid #1
– Remove PSA liner and lamination of film x using antistatic gun
and lamination roller.
– Clean upper side of film with antistatic spray
• Parameters
– Class 100 Clean Room
(probably we can use 1000 but never been tested)
• Material type: Adhesives Research PSA1
– Positioning aid #1 - Works for specific product dimensions
• Equipment
–
–
–
–
–
Antistatic spray
Laminating roller
Antistatic gun
Sharp knife
Millimetric paper
110
Simple Wet Etch or Lift-Off
•
Conveyor drive designs to accommodate a wide range of flexible and rigid printed circuit
boards up to 30 inches wide. The Belt Drive design utilizes a single piece fluoropolymer
belt for driving the conveyor surface which can accommodate most flexible substrates
without the use of support frames. The Serpentine Drive design utilizes a fluoropolymer
belt for driving the conveyor wheels which are fabricated of corrosion resistant material.
The Serpentine Drive is most suitable for rigid products and provides complete exposure
of product surface during spray processes for increased uniformity.
•
Input variables
–
–
–
–
–
•
Chemistry
Temperature
Agitation
Spray
Speed
Output variables
–
–
–
–
Etch rate
Line width control
Defect density
Selectivity
111
Example of Touch Screen Process Detail
Wet Etch
• Etch Process C
– Immersion in an etch solution
– Immersion in DI water baths
– Rinsing with DI water
– Drying in the oven
– Etch process details
• Etchant: Hypochlorite solution 2. Temp = 25C3. Time= 45 sec
– We do this in our lab in a plastic bath
– 3 baths one after the other
– first bath – 20 sec, second bath 20 sec, third bath 1 min
(Do you know why?)
– Requires Shaking the film/bath in each stage (video the motions)
• Observations
– The material swells in water and becomes sensitive to mechanical
stress
– QC – Test etched lines
• Resistance x : 300 K-ohm ± 30 K-ohm
• Resistance between lines: greater than 5 M-ohm
112
Ask the People Who Inspect the Product
Inspectors see more than they record
Automated inspection for
transparent conductors
and film defects.
113
Embedded
(In-Cell
& On-Cell)
Source: TMD
114
Three Different Physical Integration
Methods Used In Embedded Touch
Term
Integration Method
Fab Method
In-Cell
Touch sensor is physically inside the LCD cell
Touch sensor can be:
 Light-sensing elements (light-sensing)
 Micro-switches (voltage-sensing)
 Capacitive electrodes (charge-sensing)
Addition
to TFT
process
On-Cell
Touch sensor is an array of ITO conductors
on the top surface of the color filter substrate
 Capacitive (charge-sensing)
 Analog resistive (voltage-sensing)
Addition to
color filter
process
Out-Cell
Standard touchscreen laminated directly on top of
the LCD during manufacture
 Key difference: An additional piece of glass
 Typically only pro-cap or analog resistive
 New term coined by AUO – Some LCD
manufacturers still refer to this configuration
as “on-cell”
Addition to
cell
assembly
process
115
Four Different Technologies
Used In Embedded Touch
 Light-sensing or “optical”
 Addition of a photo-sensing element into some or all pixels
 Voltage-sensing or “switch-sensing”
 Addition of micro-switches for X & Y into some or all pixels
 Charge-sensing or “capacitive-sensing”
 Addition of electrodes in-cell or on-cell for capacitive sensing
 Analog resistive
 Uses color filter glass as substrate for standard touch-screen
116
In-Cell Light-Sensing
Source: DisplaySearch
 Principle
 Photo-sensor in each pixel or group of pixels sees shadow of
finger in bright light or reflection of backlight on finger in dim light
 Works with finger or light-pen; can work as a scanner
 Adding a cover-glass to protect the surface of the LCD reduces
touch sensitivity due to the spacing between the finger and the
photo-sensing element
117
In-Cell Voltage-Sensing
Source: Samsung
 Principle
 Pressing LCD surface closes micro-switches in each pixel

Similar principle as emerging analog multi-touch resistive
 Requires touching the LCD surface (cannot add a cover glass)
 Works with any touch object within damage limits of polarizer
118
In-Cell Charge-Sensing
 Principle
Source: LG Display
 Pressing the LCD changes the dielectric constant of the liquid
crystal, which changes the capacitance between the electrodes
 Works with finger or stylus; human body capacitance isn’t a factor
 Requires touching the LCD surface (cannot add a cover glass)
119
Hybrid In-Cell Voltage & ChargeSensing (Samsung hTSP)
VRef
2 sets
(X&Y)
per pixel
or group
of pixels
CRef
 Principle
Columnspacer
switch
X-Y
Bias
CLC
Amplifier
VCom
Blue pixel
Source: Author
VOut
 Pressing the LCD…
(1) Changes the
dielectric constant of
the liquid crystal,
which changes the
capacitance between
the pixel electrodes
(2) Closes the columnspacer contacts, which
activates the circuit
that measures the
change in capacitance
Sensor signal line switch (X,Y)
Source: Samsung
120
On-Cell Charge-Sensing
 Principle
Source: Author
 Projected-capacitive X-Y electrode array added
on top of the color filter glass, under the top polarizer

Same function as standard projected-capacitive
 Works only with finger; human body capacitance changes
mutual capacitance between electrodes
 Cover-glass (0.5 mm) can be added on top of polarizer
to protect LCD surface
121
On-Cell Analog Resistive
 Principle
Source: Author
 Analog resistive touch-screen added on top of the color filter
glass, under the top polarizer

Same function as standard analog resistive
 Works with any touch object within damage limits of polarizer
 Adding cover-glass (0.5 mm) on top of polarizer to protect
LCD surface works but reduces touch-screen performance
122
Products with
Embedded Touch…1
 Samsung ST10 camera with 3-inch 480x320 (192 ppi)
transflective TFT with hybrid in-cell touch (4/09)
 First use of any in-cell touch
in a commercial product
 Works with finger or stylus,
but with visible pooling
 Surface hardness = low
 Touch-screen includes
electrostatic haptic feedback
 Camera includes MP3,
PMP & text-viewer functions
 One sensor per 8 pixels
(60x40 sensing matrix)
Source: Samsung
123
Products with
Embedded Touch…2
 Sharp’s PC-NJ70A netbook (5/09)
 First use of light-sensing in-cell
touch in a commercial product
 Optical in-cell touch in 4” CG-silicon
854x480 touchpad LCD (245 dpi)






1 sensor per 9 pixels
LED backlight
Stylus & 2-finger multi-touch
Scanning (shape recognition)
Touch surface = ??
Japan-only; $815
 Problems



Need IR from backlight
S L O W (25% of typical touchpad speed)
Short battery life
Source: Sharp
124
Products with
Embedded Touch…3
 Samsung ST550 camera with 3.5-inch 800x480
(267 ppi) transflective TFT with hybrid in-cell (8/09)
“Do not use other
sharp objects, such
as pens or pencils,
to touch the
screen. Doing so
may damage
the screen.”
“The touch screen
may not recognize
your touches
correctly when:
● You touch multiple
items at the same time
● You use the camera
in high-humidity
environments
● You use the camera
with an LCD protection
film or another LCD
accessory”
“When you touch or drag on the
screen, discolorations will occur. It is
not a malfunction but a characteristic
of the touch screen. Touch or drag lightly
to reduce these annoying effects.”
Source: Samsung
(from the User’s Guide)
125
Products with
Embedded Touch…4
 LGD’s 13.3” 1280x800 in-cell charge-sensing LCD (10/09)
 Largest in-cell LCD so far


1 sensor per 4x4 pixels
10 gf activation force
 Win-7 Touch Logo 2/10
 Positioning




High optical quality
Sunlight readability (AR?)
Preserving thinness
Two-touch multi-touch
 Targeted at notebooks
 Production in 2H-2010
 Added price for touch function = ??
Source: LG Displays
126
Products with
Embedded Touch…5
 Samsung S8500 Wave mobile
phone with Super OLED on-cell
charge-sensing touch (2/10)
 3.3-inch 800x480 (283 ppi) AMOLED
 “Super OLED” is Samsung’s
(poor) branding for on-cell touch
 Sunlight readable

AR coating & no touchscreen overlay
“Window” here refers
refers to the “cover
lens” that’s laminated
on top of the display
Source: Samsung booth graphic at
Mobile World Congress 2010
Source: Samsung
127
Embedded Characteristics…1
 Advantages (summary)
 Integration, size, thickness, weight, ID (touch is “invisible”)
 Unlimited multi-touch (controller-dependent)
 Conceptually high performance

Low parallax error (assuming no cover glass)

Very accurate & linear touch-point data

Potentially higher resolution than LCD
 Lower manufacturing cost
Source: AUO
128
 Disadvantages (summary)
 Touching a black image doesn’t work in low ambient light
 Can’t reliably detect touch over the full range of ambient
 The sensor consumes too much of the pixel aperture
 Unstable microswitch contact at the edge of the screen
 The amount of processing power required by the touch
function results in high power consumption in a mobile device
 Liquid-crystal pooling can be visually distracting
 Standard LCD polarizer is too soft for normal touch usage
 Successful integration can be very difficult due to LCD noise
 Lack of stylus support with on-cell limits some applications
129
 Size range
 3” to 13.3” (current); potentially to mid-20”
 Variations
 Number of pixels per sensing element
 Controller
 Proprietary/TBD (potential problem)
 Applications
Source: Sharp
 Mobile (cellphones, cameras, netbooks, notebooks)
 Market share
 Just starting
 Suppliers
 AUO, CMI, CPT, LGD, NEC, Samsung, Sharp, Sony, TMD…
130
 Trends
 Light-sensing has the most unresolved problems

No successful end-user products yet
 Voltage-sensing isn’t getting any traction

No successful products of any kind yet (IP restriction?)
 Charge-sensing is where all the action is, mostly on-cell



LGD’s 13.3” notebook LCD (in-cell)
Samsung’s OLED cellphone (on-cell)
Samsung’s in-cell hybrid in-cell voltage & charge-sensing cameras
 Analog resistive has been shown in demos only so far
 It is unlikely that LCD manufacturers will add embedded touch
to an entire LCD product line; it will just be in high-volume
products with a high demand for touch
 Conclusion
 It’s still early days – embedded touch has some distance to go
131
Photolithography
132
Fine Line Patterning Using Photolithography
Steps Used Together
(Cross Section)
Thin Film Dep
Pattern
Etch/Clean
Cross Section
Top View
133
How Many Times Do We Pattern?
• As many layers of conductors, insulators, and
different materials as we have
• Each (with exception) requires a separate pattern or “mask”
• Re-entrant flows
• One tool is used for several steps on the same product
• 20 – 65 pattern layers in ICs
• 4 – 8 pattern layers in FPDs
• 1 – 4 pattern layers in Touch
134
Basic Steps Used for Patterning
Fine Lines Less than 25 Microns
• Photolithography
(using light to make lines)
• Coat with photosensitive film
• Align
• Develop
• Inspect
• Etch or deposit desired material
FPD Stepper
• Strip photosensitive film
• Inspect/measure
135
Uses of Photoresist
Photoresist is used as a mask, and then removed from the substrate
Barrier to Etches
Resist
Nitride & Partial Oxide Etched Away
Nitride
Oxide
Barrier to Metal Etches
Metal Etched Away
Resist protects metal
Metal 1
136
Photoresist Coating Process
• Equipment Used: Spin Coater (most common)
• Task: Apply a thin film of photoresist onto substrate
• The photoresist film must be:
1. Clean and free of particles or pinholes
2. Applied to dry substrates (may need surface modifier chemicals)
3. Correct in thickness and uniformity
4. Dried with solvents removed
5. Baked and ready for exposure
6. Photoresists are organic polymer resins (C, O, H, N) mixed with
solvents
137
Resist Coat Bake System - FPD
138
Printers
•
EQUIPMENT USED:
Scanners
Aligners (Contact, Proximity)
Steppers
Step and Scan
•
PROJECTION PRINTER (SCANNING) (8 to 75 microns):
• Uses highly reflective mirrors to project a pattern from a
photomask to the substrate
• No reduction in image size
• Prints with one continual scan across each substrate

STEP-AND-REPEAT PRINTER (STEPPER) (5 microns and below):
• Uses reflective optics (condenser & reduction lenses) to project a
pattern from a reticle to the wafer
• Optically reduces reticle image size by 5X (or 10x, 2x, or 1x)
• Prints “fields” which are stepped over each substrate
140
Flex Handling and Mid-Process Coat, Align /
Expose and Develop (Resist and Optical Materials)
Coat / Develop
Scanner
Images courtesy of SSEC and RPO Pty Ltd
141
Spray Developer – FPD
142
Positive Resist
After Exposure to Light
• De-polymerized resist is washed away during the develop
process; a spin/ spray tool is often used with base (OH)
chemicals and water or solvents
Mercury Lamp
Mask or Reticle
De-polymerized
resist after
exposure
Before
exposure
Positive Resist
Substrate
143
Tool Selection – Photo Patterning on Flex
• Azores installed at FDC (plate format).
They are working on roll-to-roll. For the
2006 model we used the Azores tool at
2.5 ft/ min, resolution down to 1.5
microns, and a cost of $9M.
• ORC Proximity Large Area Exposure at
4.5 ft/min, resolution to 12 microns, and
a cost of $422K.
• Still to be resolved
• Cost of Azores in volume
• Is there something in between?
Resolution? Cost? Mix and match?
• How to match coat, align, develop capacity
FPD Stepper / Stitcher
(Azores)
144
How Can Defects Happen
In Photolithography?
SCRATCH
PARTICLE
MASK OR RETICLE
CHROME
GLASS
LIGHT
Substrate
PHOTORESIST
DEFECTS IN PHOTO PATTERN
1 Defect
Projection
MASK
Prints the same defect on
many substrates
etc...
145
What Size Defect Is a Killer?
~ 50 nm
Amines
0.2 - 0.4 µ ?
200 – 400nm
Cigarette Smoke
2µ?
2000nm
Bacteria
8µ?
8000nm
Skin Flake
IT DEPENDS ON FEATURE SIZE:
4000nm
NMOS
4 µ CD 2500nm
1980
FPD / CF
Adv. Touch
2.5 µ CD 1500nm
HMOS
TFT
1985
1.5 µ CD 350nm
0.35 µ CD
CMOS DLM 2 µ 1989 CMOS QLM 0.35µ 1995
90nm
0.09 µ CD
Nanotechnology 2003
nm = Nanometers
146
More Process Steps Means…
More CHANCES for a defect to occur!
NMOS / TFT
HMOS
BiPolar
8
Photo
11
Diff / CVD
PVD
12
Photo
15
Diff / CVD
PVD
DLM CMOS, BiCMOS GATE ARRAYS
17
Photo
21
Diff / CVD
PVD
40
Total Steps
50
Total Steps
65
Total Steps
c 1980
c 1988
c 1993
147
What Is a Defect?

Anything that does not belong on the device

Anything that KILLS a device
DEFECT
DEFECT
OPEN
GOOD
DEVICE
SHORT
DEAD DEVICES
148
DEFECTS
YIELD
LOW Defect Density
=
HIGH Yield / Low Costs
HIGH Defect Density
=
LOW Yield / High Costs
149
Touch Screens
Risks in Fine Line Patterning – Defect Density
- Killer defect
Laptop
X
1/6 = 16.7% bad
Medium Television
X
1/4 = 25% bad
Large Television
X
1/1 = 100% bad
150
Flat Panel Displays
EACH pixel must be clean or we will see a
dark spot, bright spot, bright line, or dark line.
Each display ~ 1280 x 1068 pixels
~ 1.4 million pixels/display
Each pixel contains several transistors
For each subpixel:
R
R
G
B
R
G
G
B
151
Touch Technologies
without ITO
 Acoustic Pulse Recognition (APR by Elo)
 Dispersive Signal Technology (DST by 3M)
 (Materials & Process 5: Etch)
 Surface Acoustic Wave (SAW)
 Traditional Infrared (IR)
 Waveguide Infrared (by RPO)
 (Materials & Process 6: In-Cell / FPD)
 Optical
 Force Sensing
 Vision-Based
152
Acoustic
Pulse
Recognition
(APR)
“Zero-Bezel”
Single piece of
glass (no bezel);
black margin is
fired-on glass frit
on underside
153
Acoustic Pulse Recognition (APR)…1
 Plain glass sensor with
4 piezos on the edges
 Table look-up of bending
wave samples (“acoustic
touch signatures”)
154
 Variations
 “Stationary APR” from 10” to 52” with controller board
 “Mobile APR” from 2.8” to 10” with controller ASIC
 Size range
2.8” to 52”
 Controllers
 Proprietary
 Advantages





Works with finger, stylus or any other touch object
Very durable & transparent touch sensor
Resistant to surface contamination; works with scratches
Totally flush top surface (“Zero-Bezel”)
Very simple sensor (plain glass + 4 piezoelectric transducers)
155
 Disadvantages
 No “touch & hold”; no multi-touch
(both are under development & should appear in 2010)
 Requires enough touch-force (tap) to generate sound
 Control of mounting method in bezel is critical
 Applications
 POS, kiosks, gaming, mobile devices
 Market share
 <1% (first production in Elo monitors was at the end of 2006)
 Supplier
 Elo TouchSystems (sole source)
 Market trends
 Elo has begun shipping APR to mobile device OEMs
156
Elo’s
“Zero-Bezel”
APR with
capacitive
buttons &
scroll-wheel
in lower-right
corner
(SID 2009)
157
Dispersive
Signal
Technology
(DST)
Source: 3M
158
Dispersive Signal Technology…1
 Plain glass sensor
with 4 piezos in
the corners
 Real-time analysis
of bending waves
in the glass (“time
of flight” calculation)
Source: 3M
159
 Variations
 None
 Size range
32” to 46” (3M is likely to expand into larger sizes)
 Controller
 Proprietary
 Advantages
 Very simple sensor (plain glass + 4 piezoelectric transducers)
 Works with finger, stylus or any other touch object
 Very durable & transparent touch sensor
 Operates with static objects or scratches on the touch surface
 Fast response; highly repeatable touch accuracy; light touch
160
 Disadvantages
 No “touch & hold”; no multi-touch
 Control of mounting method in bezel is critical
 Applications
 Interactive digital signage; point-of-information (POI)
 Market share
 < 1%
 Supplier
 3M (sole source)
 Market trends
 DST still has a relatively low market profile due to 3M’s
very conservative rollout
 3M avoids cannibalizing their surface-capacitive sales (<32”)
161
APR vs. DST
Technology Comparison
Characteristic
Size range
Methodology
Measurement
Multi-touch
Touch & hold
Activation force
Controller
Mounting
Availability
Others
APR
DST
2.8”-52”
32”-46”
Table lookup
Real-time
Bending waves Bending waves
Under
Gestures
development
announced
Under
No
development
Moderate
Light
Chip (mobile)
Board (fixed)
Board (fixed)
Critical
Critical
In monitors;
In monitors
components for
mobile devices
Similar
Similar
Notes
3M surface capacitive is 5.7”-32”
3M’s “multi-touch gestures” only
work with two moving points
Neither technology has reached
the “drop-in touch-screen”
component state yet
Performance, materials, surface
treatment, interface, etc.
162
Etch
163
Processing – Etching
What Steps Are Used in Etch?
• Wet Etch
• Wet resist strip
“Lift-Off” is an etch / strip
combination process
• Inspect for defects / registration
• Measure critical dimensions
Dry or Plasma Etch
• FPD or semiconductor process
• Anisotropic etch
• Fine-line geometries
• Materials with no wet etchant
164
Etch
Must be highly “selective”
• Etches desired material much faster than
• Protective mask (usually photoresist)
• Underlying materials
• Chemistry mix is critical
• Can be enhanced by
• Heat/energy
• Plasma (RF)
• Criteria for selecting Dry or Wet Etch
• Cost (equipment depreciation, chemicals, maintenance, yield)
• Etch profile
165
Etch
• Isotropic: Etches all directions equally, chemical - Wet Etch
• Anisotropic: Etches different directions at different rates to
create shapes, “trenches”. More likely to achieve and control
etch profile with Dry Etch
Isotropic Etch
Mask
Anisotropic Etch
Mask
Mask
Mask
Material to be etched
166
Etch Chemistry
Wet Etch – Acids
ITO Thickness = 0.5 to 1.5 microns
•
ITO Etchant 1: 17% HCl, 25 C, 30-60 Angstroms/min
•
•
ITO Etchant 2: 1:0.1:1, HCl:Nitric:DI H2O @ 40 C
ITO Etchant 3: Etches Fast (125 Angstroms/sec) in 10:1 DI H2O: HF
Other common etchants:
•
Phosphoric/Hydrochloric/Acetic/Nitric: Metals
•
Hydrogen Fluoride: SiO2
•
Phosphoric: Silicon Nitride Si3N4
167
How Can Defects Happen
In Etch Process?
ETCHERS
defect
• WET ETCH:
• HOOD/ BENCH
• ACID PROCESSOR –
single substrate OR batch
Substrate
• DRY ETCH
• PLASMA
• REACTIVE ION ETCH
168
Wet Etch Equipment
Rigid and Flex Panel Processors
In-line systems for wet processing.
• Wet processes from rinsing through to developing, etching, stripping and drying performed
totally in line.
• Large glass substrates are processed by substrate oscillation, chemical spraying, speedy
upflow, etc. matched to process requirements.
• The etching module contains end point sensors for ensuring excellent processing
repeatability.
Source: Dalux
169
Resist Strip and Clean
• Strip must be highly selective to remove all
unwanted materials and leave all critical films!
Wet
Metal Layers
Solvents
- Acetone
- NMP
- PRS 3000
Solvent or water rinse
- IPA
• Options: Heating, spray patterns, rinse to resistivity, spray, recirculating tanks
• Drying is critical
• N2
• Air curtain / knife
• Iso dryer / displacement dry
Dry
• Plasma
• UV Ozone
170
Front of Gen II Wet Hood – Etch / Strip
Inside View
171
Chemical Recirculating Systems
172
Stainless Steel Wet Strip Systems
• High-temperature stainless stripping system with
integrated resist separator
• Conveyor systems available for rigid and flexible sheets
(.001” core)
Source: Dalux
173
Alternate Fine Line Processing –
Pattern and Etch in One Step
• Laser ablation system
• Single layer patterning
• High resolution
• Ease of varying pattern
• Critical input parameters
•
•
•
•
•
Laser energy
Speed
Film quality
Alignment
Pattern algorithm (software program)
• Critical output parameters
•
•
•
•
•
Ablation pattern
Registration
Resolution
Defect density
Heating / damage
174
Inspect / Metrology
• How is success measured /
evaluated?
• Probe, final test
• Until probe: Indirect
measurements
• Single parameters
• They infer probable
functionality
• Examples:
•
•
•
Critical dimensions
Particle counts
Automatic optical inspections
• Interactions of individual
parameters abound!
Key parameters:
• Film thickness
• FTIR
• Profilometer
• Resistivity / conductivity
• Inductance
• Critical dimensions
• Widths / lengths
• Light reflection
• Physical structure /
Morphology / step coverage
• Profilometer
• SEM
175
Inspection Tool
FPD, PC Board, Touch Screen
Orbotech SuperVision-650™
High-sensitivity AOI for the 6th
generation
SuperVision-650™, the world's very
first AOI system for 6th generation
panels, provides high sensitivity
detection and better throughput.
176
Surface
Acoustic
Wave
Source: Kodak
177
Surface Acoustic Wave…1
Glass substrate
Source: A-Touch
(45°)
Rayleigh wave
Source: Onetouch
178
179
 Variations
 Ruggedization, dust-proofing, surface treatments, etc.
 Size range
 6” to 52” (but some integrators won’t use it above 32”)
 Controllers
 Mostly proprietary
 Advantages




Clear substrate (high optical performance)
Very durable
Can be vandal-proofed with tempered or CS glass
Finger, gloved hand & soft stylus activation
180
 Disadvantages





Very sensitive to any surface contamination, including water
Requires “soft” (sound-absorbing) touch object
Can be challenging to seal
Relatively high activation force
Projects slightly above touch surface (1 mm) so can’t be flush
 Applications
 Kiosks
 Gaming
 Market share
2009
Revenue
3%
Units
<1%
Source: Euro Kiosks Network
181
 Suppliers
 Elo TouchSystems, General Touch, Shenzhen Top-Touch,
Leading Touch, Shenzhen KeeTouch…
 10+ suppliers
 Market trends
 Price is dropping as Taiwanese and Chinese vendors
enter the market now that Elo TouchSystems’ key patent
has expired

Elo still has >50% of this market
 SAW’s growth is matching the market
182
Elo’s “XYU”
multi-touch
SAW
(demoed at
SID 2009;
launched
12/09)
Photo by Geoff Walker
183
Traditional
Infrared
184
Traditional Infrared…1
185
 Variations
 Bare PCA vs. enclosed frame; frame width & profile height;
enhanced sunlight immunity; force-sensing
 Size range
 8” to 150”
 Controllers
 Mostly proprietary, except IRTouch
 Advantages





Scaleable to very large sizes
Multi-touch capable (2-4 touches)
Can be activated with any IR-opaque object
High durability, optical performance and sealability
Doesn’t require a substrate
186
 Disadvantages
 Profile height (IR transceivers project above touch surface)
 Bezel must be designed to include IR-transparent window
 Sunlight immunity can be a problem in extreme environments
 Surface obstruction or hover can cause a false touch
 Low resolution
 High cost
 Applications
 POS
 Kiosks
 Large displays (digital signage)
 Market share
2009
Revenue
1.5%
Units
<1%
187
 Selected suppliers
 Elo TouchSystems, IRTouch, Minato, Nexio…
 10+ suppliers
 Market trends
 Interest in IR is re-awakening
as Asian vendors bring down
prices, large displays
become more common, and
digital signage becomes
more affordable
 IR is growing, but isn’t keeping
up with the market
50” plasma display with infrared touch-screen from Netrax
188
Optical
Waveguide
Infrared
Source: RPO
189
Waveguide Infrared…1
Principle
Traditional
Infrared
Source: RPO
190
RPO’s actual
construction
(3.5” screen)
Substrate
Parabolic
reflector
IR LED
Light path
(white)
Waveguides
Line-scan
optical sensor
Photo source: RPO;
Annotation by author
Light path
(uses TIR
in substrate)
191
 Variations
 None yet
 Size range
 3” to 14”
 Controller
 Proprietary
 Advantages
 Much lower cost than traditional IR
Source: RPO
 Very low profile height (0.5 mm)
 Higher resolution (depending on waveguide channel width)
 Much less pre-touch (IR is only 200µ above substrate)
 Works with a finger, stylus or any other touch object
 Object size recognition
 Limited multi-touch
192
 Disadvantages
 Can’t be scaled easily to large sizes (border width)
 Power consumption (positioned as = to light loss of resistive)
 The “fly on the screen” problem (IR is only 200µ above substrate)
 Applications
 Mobile devices & automotive (maybe)
 Market share
 Not in a shipping device yet as of 01/10, although
RPO says they now have a committed OEM
 Suppliers
 RPO (Australian startup; sole source)
193
 Market events
 RPO…




Announced IR optical-waveguide touch at SID 2007
Showed improved performance at SID 2008
Showed larger sizes at SID 2009
Appeared in a 13.3” LD Display notebook at SID 2010
 Market trends
 RPO may benefit from the general increase in interest in
infrared, as well as from the growing interest in alternative
touch technologies for mobile
194
In-Cell & FPD
195
Three Different Physical Integration
Methods Used In Embedded Touch
Term
Integration Method
Fab Method
In-Cell
Touch sensor is physically inside the LCD cell
Touch sensor can be:
 Light-sensing elements (light-sensing)
 Micro-switches (voltage-sensing)
 Capacitive electrodes (charge-sensing)
Addition
to TFT
process
On-Cell
Touch sensor is an array of ITO conductors
on the top surface of the color filter substrate
 Capacitive (charge-sensing)
 Analog resistive (voltage-sensing)
Addition to
color filter
process
Out-Cell
Standard touchscreen laminated directly on top of
the LCD during manufacture
 Key difference: An additional piece of glass
 Typically only pro-cap or analog resistive
 New term coined by AUO – Some LCD
manufacturers still refer to this configuration
as “on-cell”
Addition to
cell
assembly
process
196
Four Different Technologies
Used In Embedded Touch
 Light-sensing or “optical”
 Addition of a photo-sensing element into some or all pixels
 Voltage-sensing or “switch-sensing”
 Addition of micro-switches for X & Y into some or all pixels
 Charge-sensing or “capacitive-sensing”
 Addition of electrodes in-cell or on-cell for capacitive sensing
 Analog resistive
 Uses color filter glass as substrate for standard touch-screen
197
Simplified Structure of an LCD Cell
Touch Screen
FRONT POLARIZER
FRONT GLASS
Light
LIQUID CRYSTAL MATERIAL
REAR GLASS
REAR POLARIZER
ITO ELECTRODES
Backlight
198
Liquid Crystal Displays
TWISTED NEMATIC
twist angle 90deg.
Upper Polarizer
SUPERTWISTED NEMATIC
twist angle 180deg. - 270deg
Glass
ITO Electrode
No field applied
Light/off
Liquid Crystal
ITO Electrode
Glass
Lower Polarizer
Upper Polarizer
Field applied
Dark/on
Glass
ITO Electrode
Liquid Crystal
ITO Electrode
Glass
Lower Polarizer
199
Active Matrix Liquid Crystal Display = AMLCD
UPPER COLUMN DRIVER
TFT AMLCD
Resistor
Photo-sensor in each pixel or
group of pixels sees shadow of
finger in bright light or reflection of
backlight on finger in dim light.
DISPLAY CELL
R
O
W
D
R
I
V
E
R
Thin Film
Transistor (TFT)
Capacitor
Same TFT
Process
LOWER COLUMN DRIVER
• Putting a light-sensor in every pixel consumes too
much of the aperture (reducing efficiency) and
requires too much processing power
• But using one light-sensing element for each X pixels
(e.g., 9) reduces scanning resolution and reduces
quality of digital ink
200
AMLCD TFT Pixel Structure - Typical
TOP View TFT
Top View – Voltage-Sensing 1
GATE
LINE
METAL
DATA
LINE
i-Si
PIXEL ITO
CAPACITOR
LINE
201
In-Cell Touch
Amorphous Silicon TFT
COMPONENT
Polarizer
Glass: Color Substrate
B
G
R
R
G
B
Color filter
ITO
Alignment Layer
Sealing Adhesive
Liquid Crystal
Drain Bus
Gate Bus
a-Si TFT
Backlight
Pixel Electrode
Spacer
Alignment Layer
Glass: TFT Substrate
Polarizer
202
Voltage and Charge Sensing
Side View – Voltage Sensing 2
Column spacer
with ITO coating.
Side View – Charge Sensing
(“Pressed Capacitive”)
Consistency of capacitance
value of LC material is critical
May require
additional steps.
203
Cross Section of TFT LCD
We are looking at this side.
TOP GLASS SUBSTRATE (COLOR FILTER)
BLACK STRIPE
ITO
COLOR FILTER
PASSIVATION
SPACER
LIQUID CRYSTAL LAYER
Sealing Material
(Adhesive)
POLYIMIDE (ALIGNMENT)
PIXEL ELECTRODE ITO
PASSIVATION
DATA LINE
BOTTOM GLASS SUBSTRATE (TFT ARRAY)
Light
204
Charge-Sensing…2
 On-cell
• Projected-capacitive X-Y electrode array added on top of the
color filter glass, under the top polarizer
Source: Author
Needs touchfriendly polarizer,
6H to 9H
hardness.
205
AMLCD Production Process
Lighting
TFT Fab
Plate/Cell
Assembly
Materials
Final
Assembly
Testing
Color
Filter Fab
Electronics
Addition of “ONCELL” Touch Array
206
Cell Assembly Process
COLOR FILTER SUBSTRATE
TFT SUBSTRATE
Cleaning
Cleaning
Polyimide Coating
Polyimide Coating
Baking
Baking
Rubbing
Rubbing
Cleaning
Cleaning
Seal Printing
Spacer Spraying
Conductive x-over dots
Align / Assemble / Cell Space Adjusting
Scribe
Scribe/ /Cell
/Break
Break
Align / Assemble
Space Adjusting
Liquid Crystal Filling / Annealing
Inspection
Cleaning / Polarizer Lamination
207
a-Si TFT Process
GATE METAL
DEPOSITION
PHOTOLITH
/ETCH
TO DEFINE GATE
DEPOSIT
GATE INSULATOR
i A-SILICON &
n+ A-SILICON
PHOTOLITH / ETCH
TO DEFINE CHANNEL
DEPOSIT
SOURCE / DRAIN
METAL
PHOTOLITH / ETCH
TO DEFINE
SOURCE / DRAIN AND
ETCH BACK CHANNEL
For In-Cell, Add
Sensor Design to
this Flow
DEPOSIT ITO
PIXEL PAD
PHOTOLITH / ETCH
TO DEFINE ITO
208
Active Device Formation
Process
First Wash/Clean
Type
Thin Film Deposition
Equipment
Single Substrate Processor
Type
Sputter
Plasma CVD
Clean
Batch or Single Substrate Processor
Apply Resist
Extrusion orSpin Coater
Prebake
Conveyor Oven or Hot Plate
Exposure
Stiches Stepper or Full Wafer
Projection Expose
Develop
Single Substrate Processor or Batch
Postbake
Conveyor Oven or Hot Plate
Etching
or Batch Dip/Spray/Dry Plasma or RIE
Stripping
or Batch Plasma or RIE
Drying
Inspection/Repair
R
e
p
e
a
t
Conveyor Oven, Hot Plate
Optical/Electrical Test
Laser Repair
209
Flow Chart – TFT Bottom Plate, TFT and Pixel Fabrication
Clean
Borosilicate
Glass
Sputter Deposit
Gate Metal 1
eg: Al or Cr
Photolith Pattern
Gate and Wet Etch
Gate Metal 1
PECVD Deposit,
Nitride, Amorphous
Silicon, Silicon
Films
Photolith Pattern
silicon
RIE silicon
Sputter Deposit
Gate Metal 2
eg: Al or Ta
Photo Pattern
and Etch
Gate Metal 2
Eg: Ta
Anodize
Gate Metal
Photo Pattern &
Dry Etch
SixNx Silicon
Nitride
Sputter Deposit
ITO
Photo Pattern
Pixels
and Wet Etch ITO
Sputter Dep
Gate Metal 3
eg: MoTa, Al or Cr
S/D Metal 3
Photo Pattern
Source/Drain
and Wet Etch
S/D Metal 3
RIE N+
Amorphous
Silicon
Substrate Clean
Deposit
Passivation
SixNx Nitride
Photo Pattern &
Dry Etch (RIE)
SixNx Nitride
Final Test/
Inspect Pattern
Laser
Repair
Shorts
Final QC
Send to Liquid
Crystal
Details would change for
In-Cell Sensor
210
Top Plate Flow Chart, Black Matrix and Color Filters
Clean
Borosilicate
Glass
Ash
Plasma Clean
PECVD Deposit
SixNx Silicon
Nitride
and Silicon
Substrate Clean
Sputter Deposit
Chrome
Photo Pattern
Black Matrix
and Wet Etch
Chrome
RIE
SixNx Nitride
and Silicon
Resist Coat,
Align, Develop,
Strip resist, Hard
Bake Polyimide
Blue Filter
Apply and Bake
Green Filter
Polyimide
Apply and Bake
Resist Coat, Align,
Develop, Strip
resist, Hard Bake
Polyimide
Red Filter
Apply and Bake
CAP Layer
Deposit
(polyimide or
Nitride)
Sputter Deposit
ITO
Final Q.C.
Resist Coat, Align,
Develop, Strip
resist, Hard Bake
Polyimide
Send to
Liquid Crystal
Details would change for
Voltage and Charge
Sensing In-Cell Touch
211
a-Si TFT Process Architecture – Bottom Gate
6
3
2
SiN
Metal
5
4
ITO
1
Insulator
1
Gate
n+
Si
i
3
6
2
4
Si
5
Si
1
Glass Substrate
i
Insulator
1
n+
Si
Gate
Glass Substrate
a.) Self-aligned
b.) Non-self-aligned
LEGEND
3.)Moly Tantalum
Masking Steps
Process Steps
Materials
1. Gate Pattern
1. Metal Dep
1. Aluminum Tantalum (AlTa)
2. Etch Stop Pattern
2. PECVE Dep
2. a‐Si Amorphous Silicon
n+ amorphous Silicon
Si3N4 Silicon Nitride
3. Channel Pattern
3. Metal Dep
3. MoTa (Moly Tantalum)
5. ITO Pattern
5. ITO Dep
5. ITO (Indium Tin Oxide)
6. Metal Pattern
6. Metal Dep
6. MoTa (Moly Tantalum)
7. Passivation Pattern
7. Passivation
7. Polymide or Si3N4 Silicon Nitride
4. Gate Cut Pattern (non‐self aligned only)
212
Cross Section: High Temperature poly-Si TFT – Top Gate
n-poly-Si - Gate Electrode
A1 - Signal Line
ITO - Picture Element
Electrode (PIXEL)
APCVD SiO2 - Layer Insulation
Film
Glass Substrate
Thermal Oxide SiO2 - Gate Insulation
Film
i-poly-Si
n-poly-Si
213
Plan View of
TFT Device with Added Sensors
Example of additional sensors in a TFT cell
• Gate is Red
• Signal lines are Blue
• Contacts are green
Easy to see how aperture can be smaller as sensors are added.
214
Mechanical Effects – Cover Glass
vs. Touch Requirements
•
Voltage-sensing won’t work with a cover glass,
so the LCD can easily be damaged
• AUO’s 2008 spec is only 100K touches at <40 grams! – although
it’s unclear if it’s limited by LCD surface damage or ITO cracking
•
Typical resistive touchscreen spec is 1M touches (4-wire)
or 30M touches (5-wire) at ~80 grams
• Harder LCD top-polarizer is the best solution to this problem,
but until there’s more demand for touch, it’s chicken-and-egg
• Adding a cover-glass to protect the LCD reduces touch sensitivity
due to the spacing between the finger and the photo-sensing element
• Will the repeated flexing of the glass cause eventual fatigue and
failure?
•
•
Glass is amorphous
Tests show varying toughness, hardness, and crack failure by glass
vendor and thickness. (Reference previous AGI project with USDC)
215
Sample of Previous AGI
Mechanical Study of Glass
7.0 Conclusions
The conclusions from this experimentation are as follows:
1.
AGI has established a robust method, apparatus and visual inspection for repeatable
edge chipping analyses on glass.
2.
At the 99% confidence level, glass thickness, glass type and impactor material are
statistically significant. At a confidence level of less than or equal to 98.1% all factors
including edge type are significant.
3.
There appears to be an order of significance. This is, from higher to lower, glass
thickness, impactor material, glass type and edge type.
4.
Thinner glasses (0.4 mm) are much more likely to sustain edge fracture from impact
than 0.7 or 1.1 mm glass. Generally, there was an order of magnitude difference
between 0.4 and 0.7 mm glass for the impact energy to fracture.
5.
All metal/ glass contact should be carefully scrutinized, avoided or eliminated.
6. Through repeated impact testing, a factor of safety has been established to protect glass
from repeated impacts and other variations.
216
Optical
This picture was drawn on a 46" LCD equipped with a NextWindow optical
touch-screen by a visitor to the AETI Exhibition in London on January 24, 2006.
Source: NextWindow
217
Optical…1
218
Optical…2
 Variations
 OEM
 Bezel-integrateable
 Strap-on (aftermarket)
 Size range
 15” to 120”
 Controllers
 Proprietary
Source: NextWindow
219
Optical…3
 Advantages





Stylus independence (ADA-compliant)
Superior drag performance
Scalability to large sizes
Multi-touch (dependent on # of sensors)
Object size recognition
HP TouchSmart all-in-one computer
Source: HP
 Disadvantages
 Profile height (~3 mm on a 19” screen)
 The “fly on the screen” problem
(susceptibility to contaminants)
 Applications
 Consumer touch monitors & AiOs (market leader)
 Interactive digital signage; education
220
Optical…4
 Market share
2009
Revenue
3%
Units
<1%
Dell
Studio
One
Source: Dell
 Suppliers
 NextWindow, Quanta,
Lumio, Xiroku, eIT (XYFer)
 Market event
 NextWindow shipped more than 0.75 million touchscreens in
2009 to Asus, Dell, HP, Lenovo, Medion, NEC, Samsung & Sony
 Market trends
 Touch on the consumer desktop is just starting
 The market is just becoming aware of optical touch
221
Force
Sensing
222
Force Sensing…1
 Principle
 Suspend the touch-screen from forcesensors (strain gauges or piezos)
such that movement is constrained
to only the z-axis
Force sensor (4)
Slot (4)
Frame
 Variations
 IBM “TouchSelect”: Strain gauges
(early 1990s, unsuccessful)
 Vissumo: “Beam-mounted” sensors
(ran out of money in 2009)
 F-Origin: “Monofilament-mounted”
sensors (nothing left except IP)
 Size range
Touch area
(Vissumo’s design)
 5”-48”
223
Force Sensing…2
 Advantages
 Complete substrate design freedom – no other touch
technology can handle three-dimensional substrates
with embedded moving objects
 Disadvantages
 No vibration under 10 Hz; no rapid-fire touches
(>200 ms required between touches); no multi-touch
 Applications
 3D architectural applications
 Market share
 Zero
(F-Origin’s
undisclosed
design)
Source: Vissumo
224
Force Sensing…3
 Market trends
 Vissumo’s “architectural” focus (e.g., a 3D elevator control
panel made of steel, glass & stone containing an embedded
LCD with “soft keys” and a speaker) was strongly differentiated
with some unique capabilities
225
Force Sensing…4
4 strain gauges
supporting one
touch panel
Vissumo’s Amazing Demo Box
Irregularly shaped,
raised, textured,
wooden touch
surface
Motor attached to
and penetrating
touch panel with
printed speed
control keys and
push-pull control
lever
Glass-covered LCD integrated into touch panel
with “soft keys” printed on back of glass
Raised, marble
touch surface
with toggle
switches
penetrating
touch panel
Multi-page
“book” with
touchable &
movable
metal pages
“Snap-dome” keys attached to touch panel; removable padded and
textured keys; speaker attached with holes through the touch panel.
226
VisionBased
Source: Perceptive Pixel
227
Vision-Based…1
Principle (simplest version)
Multiple touch points;
Image taken without a diffuser
(Source: Perceptive Pixel)
Source: Perceptive Pixel
Frustrated Total
Internal Reflection
(FTIR)
228
Vision-Based…2
Microsoft
Surface
“Surface computing is about integrating the physical and
virtual worlds through the use of vision-based touch”
Source: Information Display
Projector
resolution
1024x768
------------Touch
resolution
1280x960

Source: Popular Mechanics
1 – Screen with diffuser
2 – IR LED light source
3 – Four IR cameras
4 – DLP projector
5 – Vista desktop
229
Vision-Based…3
 Variations
 IR injected into the cover glass; touch points seen via FTIR
 IR illuminates underside of cover glass; touch points reflect IR
 Size range
 As described, 30” and up
 Substrates
 Glass or acrylic
 Advantages
 Combination touch-screen and rear-projection screen
 Alternative to IR and projected-capacitive for rear projection
 Unlimited multi-touch (MS Surface spec is 52 touches max)
230
Vision-Based…4
 Disadvantages
 As described, for use with rear-projection only
 Finger-only (FTIR) or IR-reflecting object (Surface)
 Applications
 Interactive “video walls”; digital signage; high-end retail
 Market share
 << 1%
 Suppliers




Microsoft (Surface)
Perceptive Pixel (Jeff Han’s famous videos)
GestureTek & others
“”Build Your Own Multi-Touch Surface
Computer” – Maximum PC magazine (4/09)
www.maximumpc.com/print/5878
Source: NORTD
231
Vision-Based…5
 Market event
 The emergence of Microsoft’s Surface product as an actual,
for-sale, shipping product rather than just a research platform
 Market trends
 Because a vision-based touch system can be assembled very
easily, it’s the most common platform used for research
 Interest in vision-based touch is rapidly increasing

Google “touch table” for one view of related activity
232
Comparing
Touch
Technologies
233
Touch Technology vs. Screen Size
Small
Medium
Large
Touch Technology
2" – 10" 10" – 30" 30" – 150"
Analog Resistive
High
Medium
X
Multi-Touch Resistive
High
Low
X
Surface Capacitive
Low
High
X
X
High
Medium
Low
High
High
High
Medium
Medium
Optical
X
High
High
APR
Medium
High
Low
DST
X
X
High
Force Sensing
Low
Medium
Low
Waveguide Infrared
High
Low
X
Vision-Based
X
X
High
LCD In-Cell (Light)
Medium
Low
X
LCD In-Cell (Voltage)
Medium
Low
X
LCD In-Cell (Charge)
Medium
Low
X
LCD On-Cell (Charge)
High
Medium
X
Market
penetration
and/or
applicability
High
Medium
Low
X (None)
234
Touch Technology vs. Application
Application
Example
Analog Resistive
Surface Capacitive
SAW
Traditional IR
Waveguide IR
Optical
APR
DST
Force Sensing
LCD In-Cell (Light)
Touch Technologies
Kiosk Point of Info (POI)
Kiosk Commerce
Kiosk Ruggedized
Point of Sale (POS)
Office Automation
Industrial Control
Medical Equipment
Healthcare
Military Fixed & Mobile
Training & Conference
Legal Gaming
Amusement Gaming
In-Vehicle
ATM Machine
Mobile Device
Appliance
Architectural
Consumer AiO & Monitor
Music Controller
Digital Signage
Museum information
Digital photo printing
Gas pump
Restaurant; lottery
Office monitor
Machine control
Medical devices
Patient info monitor
Submarine console
Boardroom display
Casino machine
Bar-top game
GPS navigation
ATM machine
Smartphone
Refrigerator door
Elevator control
HP TouchSmart
Jazz Mutant
Thru-window store
O
O
X
O
O
O
O
O
O
O
X
X
O
X
O
O
X
O
O
X
X
X
X
X
X
O
X
X
X
X
X
X
X
X
O
X
O
X
O
X
O
O
O
O
O
O
X
X
O
X
O
O
X
O
X
X
X
X
X
X
X
O
O
O
X
X
O
X
X
X
X
X
O
O
O
O
X
X
O
O
O
O
O
O
O
O
O
O
X
O
X
O
X
O
X
X
X
O
X
O
O
X
O
O
X
O
X
X
O
O
X
X
X
O
X
X
X
X
X
O
X
X
X
X
X
X
X
X
X
X
X
X
O
X
O
X
X
X
X
X
O
X
X
X
X
X
X
X
X
O
X
X
X
X
X
X
X
O
X
O
O
O
X
O
X
X
O
O
X
X
X
O
X
X
O
O
X
X
X
O
O
O
X
X
X
X
X
X
X
O
X
X
X
X
X
X
X
X
X
O
X
X
O
O
X
O
X
X
X
X
X
X
X
X
O
X
O
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
O
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
O
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
O
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
O
X
X
X
X
X
235
13 Usability Characteristics
Surface Capacitive
SAW
Traditional IR
Waveguide IR
Optical
APR
DST
Force Sensing
LCD In-Cell (Light)
Desirable Characteristic
There is
Analog Resistive
Touch Technologies
H
H
L
H
L
M
M
M
L
H
H
H
L
H
H
H
H
L
M
M
H
L
H
H
H
L
L
H
L
H
M
H
H
L
H
H
M
L
M
L
H
H
H
H
H
H
H
M
H
H
H
H
M
H
M
H
H
M
M
H
M
H
L
L
H
H
L
M
H
H
H
M
H
M
H
M
L
H
H
L
M
H
H
H
H
H
M
H
L
L
H
H
L
M
H
H
H
H
H
M
H
M
L
H
H
H
L
L
H
M
M
H
M
H
H
L
M
H
H
L
L
H
H
H
H
M
H
H
L
H
H
H
L
H
H
L
L
H
M
H
H
H
H
M
H
H
H
M
H
L
H
M
H
L
L
L
M
H
H
H
L
H
H
H
L
L
L
L
L
M
H
H
H
L
H
M
H
L
L
L
L
L
L
H
H
H
H
H
M
H
M
H
H
H
H
Usability
Touch with any object
No unintended touch
Multi-touch
Touch & hold
High durability
High sensitivity (light touch)
Fast response & drag
Stable calibration
Very smooth surface
No liquid crystal pooling
Resistant to contaminants
Works in rain, snow & ice
Works with scratches
236
13 Performance Characteristics
Analog Resistive
Surface Capacitive
SAW
Traditional IR
Waveguide IR
Optical
APR
DST
Force Sensing
LCD In-Cell (Light)
Touch Technologies
L
H
H
H
H
H
H
H
L
L
L
H
H
L
M
H
M
H
H
H
H
L
M
L
M
H
M
H
M
M
L
H
L
H
H
L
L
L
L
M
H
M
H
M
H
L
H
H
H
M
M
H
H
M
M
H
L
H
H
H
H
L
M
L
L
H
L
M
M
L
H
H
M
H
L
L
L
L
H
H
H
H
M
H
H
H
H
H
L
M
M
H
H
M
M
M
H
H
M
H
H
L
H
L
H
M
M
M
H
H
H
H
H
L
L
L
H
H
M
M
M
L
M
H
H
H
L
L
L
L
H
L
H
H
H
L
H
H
H
L
H
L
L
H
M
H
H
H
H
L
L
H
M
L
M
M
H
H
H
H
L
H
L
H
M
H
L
H
L
H
L
H
H
M
H
L
H
M
M
L
L
L
M
H
M
H
M
H
M
H
H
H
M
M
H
no perfect
Performance
High optical performance
High resolution
High linearity
High accuracy & repeatability
Insensitive to vibration
Insensitive to EMI & RFI
Insensitive to ambient light
Insensitive to UV light
Touch-object size recognition
Measures Z-axis
Handwriting recognition
Works with bi-stable reflective
237
13 Integration Characteristics
SAW
Traditional IR
Waveguide IR
Optical
APR
DST
Force Sensing
LCD In-Cell (Light)
Surface Capacitive
(Burma Shave)
touch
technology!
Analog Resistive
Touch Technologies
M
M
H
M
H
H
H
L
M
H
L
H
H
M
L
M
M
M
H
H
L
M
H
L
M
H
L
M
L
M
M
L
H
M
L
H
L
L
L
H
H
L
H
H
H
H
H
H
H
L
L
H
L
M
M
M
L
L
L
H
L
M
L
L
H
H
M
M
L
L
L
M
M
L
M
L
L
L
H
L
M
M
M
M
M
M
L
H
L
M
H
H
H
H
L
L
L
L
L
L
H
H
M
L
L
H
L
H
H
L
H
H
L
L
L
M
H
L
H
L
H
H
L
H
H
L
L
H
L
L
H
H
M
M
M
L
M
H
H
L
L
H
H
L
L
H
H
H
H
M
L
H
H
L
L
L
L
L
H
M
H
H
L
L
L
H
L
H
L
L
L
H
M
H
H
L
L
L
H
L
M
L
L
L
H
H
H
H
M
L
H
H
L
M
L
Integration
Substrate independence
Scalable
Easy integration
Flush surface (low profile)
Narrow border width
Thin and light
Easy to seal
Can be vandal-proofed
Works on curved surface
Can be laminated to LCD
HID (Plug & Play) interface
Simple controller
Controller chip available
238
Conclusions
Source: CG4TV
239
There Is No Perfect
Touch Technology!
Technology
Analog Resistive
Analog Multi-Touch Resistive
Surface Capacitive
Waveguide Infrared
Optical
Acoustic Pulse Recognition
Dispersive Signal Technology
Force Sensing
Vision-Based
LCD In-Cell (Light-Sensing)
LCD In-Cell (Voltage-Sensing)
LCD In-Cell (Charge-Sensing)
LCD On-Cell (Charge-Sensing)
Major
Advantage
Low cost
Multi-touch
Touch sensitivity
Multi-touch
Durability
Reliability
Low cost
Scalability
Any touch-object
Any touch-object
3D substrate
Multi-touch
Integration
Integration
Integration
Integration
Major Flaw
Low durability
Connections
High drift
Finger-only
Soft touch object
High cost
Contamination
Profile height
No touch & hold
No touch & hold
Vibration
Rear projection
Sensitivity
Durability
Durability
Finger-only
240
A Prediction of Which Technologies
Will Win in the Next Five Years
Application
Automotive
Casino Gaming
Consumer AiOs
and Monitors
Consumer Notebooks
Interactive
Digital Signage
Kiosks
Mobile Devices
POS Terminals
Winning
Technology
Analog Resistive
Optical
Runner-Up
Technology
Surface Capacitive
Optical
Analog Multi-Touch
Resistive
Analog Resistive
Surface Capacitive
Analog Resistive
241
Thank You!
Geoff Walker
Marketing Evangelist & Industry Guru
NextWindow
7020 Koll Center Parkway, Suite 138
Pleasanton, CA 94566
1-408-506-7556 (mobile)
[email protected]
Abbie Gregg
President
Abbie Gregg, Inc.
1130 East University Drive, Suite 105
Tempe, Arizona 85281 USA
480-446-8000 x107
[email protected]
242
Appendix-1
Why There Are
So Many Touch
Technologies
243
Why Are There So Many
Touch Technologies?
 Proliferation of touch
 Touch is an indirect measurement
 There is no perfect touch technology
 The drive for fundamental intellectual property
 Vertical integration
Source: Gizmodo
244
 Proliferation of Touch
 Self-service reduces cost
 Displays everywhere at low cost
 Touch user interfaces are simpler
 Direct manipulation is easier
 Everything is shrinking
 Touch makes globalization easier
 Expectation of touch everywhere

245
 Touch Is An Indirect Measurement
Touch Technology
Resistive (all forms) &
Embedded (voltage)
Surface capacitive
Surface acoustic wave
Projected capacitive,
Embedded (charge)
Optical & Infrared (all forms),
Embedded (light) in high ambient
Embedded (light) in low ambient
Vision-based
Acoustic Pulse Recognition (APR) &
Dispersive Signal Technology (DST)
Force sensing
What’s Being Measured
Voltage
Current
Time delay
Change in capacitance
Absence of light
Presence of light
Image
Bending waves
Force


246
 There Is No Perfect
Touch Technology

Characteristic
Resist. P-Cap
Stylus independence
Multi-touch
High durability
High optical performance
Flush surface
Stable calibration
Narrow borders
Substrate independence
Low cost
Multiple suppliers
H = High (Best)
M
L
L
L
M
H
L
M
M
H
H
L
H
H
M
H
M
H
M
H
L
H
APR
AMR
W-IR
Embed.
H
L
H
H
H
H
H
H
M
M
L
M
H
L
L
M
H
L
M
M
M
M
M
M
H
H
M
M
H
M
H
M
L
L
H
M
H
H
L
H
H
H
L
M
M = Medium (OK)
L = Low (Worst)
247
 The Drive For Fundamental
Intellectual Property
 The fundamental intellectual property (IP) on all four*
of the traditional touch technologies has expired
 New patents tend to be on enhancements
 



 Companies trying to establish a
sustainable competitive advantage
create new touch technologies
* Analog resistive, surface capacitive, SAW & IR
e.g., Touchco,
SiMa Systems,
FlatFrog
& others…
248
 Vertical Integration
 LCD embedded (in-cell) touch
 When touch was insignificant, LCD manufacturers ignored it
 Now that it has become more significant, LCD manufacturers
want to embed it into their products (in-cell touch)

249
Appendix-2
Electromagnetic
Resonance
(EMR)
Pen Digitizer
Source: Wacom
250
EMR Pen Digitizer…1
Pressure-sensitive
capacitor (CTip)
Source: Wacom
Cordless pen
without battery
L
CMai
CTi
n
p
CSid
e
Pen equivalent circuit
Transmitted RF
Coil (L)
Side
switc
h
Sensor grid schematic
Received RF
LCD
Sensor grid
(10µ copper)
many wires
Controller
chipset
5-8 wires
Serial/USB
interface
to host
Source: Wacom
251
 Variations
 Sensor substrate (rigid FR4 vs. flexible 0.3 - 0.6 mm PET)
 Pen diameter (3.5 mm “PDA pen” to 14 mm “executive” pen)
 Size range
14”
 2” to 14”
 Controllers
2”
 Proprietary
 Advantages
Controller for 10.4”
Source: Wacom
 Very high resolution (1,000 dpi)
 Pen “hover” (mouseover = move cursor without clicking)
 Sensor is behind LCD = high durability & no optical degradation
 Batteryless, pressure-sensitive pen
Single controller can
run both pen digitizer &
pro-cap finger touch
252
 Disadvantages
 Electronic pen = disables product if lost; relatively expensive
 Difficult integration requires lots of shielding in mobile computer
 Sensor can’t be integrated with some LCDs
 Single-source = relatively high cost
 Applications





Tablet PCs
Opaque desktop graphics tablets
Integrated tablet (pen) monitors
E-book readers
Smartphones… but zero traction
 Market share
Wacom “Bamboo” Tablet
 100% share in Tablet PCs

Failed challengers: FinePoint/InPlay, Aiptek, Acecad,
KYE, Synaptics, UC-Logic, Wintime
 Majority share in graphics tablets & tablet monitors
253
 Suppliers
 Wacom, Hanvon, Waltop, UC-Logic/Sunrex
 Market trends
 Microsoft significantly de-emphasized the pen in Windows 7,
so Wacom is selling into Tablet PCs against a headwind
 Pen in general is undergoing a lessening of importance



iPhone and many imitators
Tablet PCs still a niche
iPad… doesn’t have a pen!
 E-book readers are a natural
fit IF annotation is important…
E-Ink 9.7”
Prototype
EMR Kit
254
Appendix-3
Touch
& Flexible
Displays
Source: Cambrios
255
Touch Technologies &
Flexible Displays
Touch Technology Applicability Reason
Pro-Cap &
On-Cell (Charge)
Pen Digitizer
In-Cell (Light)
Analog & Digital
Resistive
High
High
High
Medium
Surface Capacitive
Low
Surface Acoustic
Wave (SAW)
In-Cell
(Charge & Voltage)
Bending Wave
(APR & DST)
Force Sensing
Optical
Infrared (All types)
Vision-Based Optical
Low
None
Single flexible substrate;
may need ITO replacement
Flexible sensor behind display
Involves only LCD backplane
Film-film construction;
Might be possible;
Unlikely due to need for
flexible reflectors
Depends on frontplane-tobackplane spacing
None
Requires rigid substrate
None
None
None
None
Requires rigid substrate
Light travels in a straight line
Light travels in a straight line
Rear-projection only
256
Examples of Flexible Touch…1
ASU-FDC: Pen substrate, Wacom
pen digitizer; Epson display
controller also supports resistive
touch, but it’s not implemented
in this particular prototype
QUE/PlasticLogic: Flexible screen in a
rigid device; flexible projected capacitive
257
Bridgestone:
Flexible resistive?
(10.7”, 5.8 mm thick)
AUO & SiPix: Potentially flexible
pro-cap touchscreen on a
glass-substrate e-book reader
(reflectivity 33%  27%)
(Same screen
in Jinke A6
& A9 readers)
258
Concept shown by LG Display at SID 2009
 2 sensors per 10x12 pixels (dpi = 174)
 What about touching a black object?
259
Appendix-4
ITO
Replacement
Materials
Source: Asylum Research (800 nm scan of ITO)
260
ITO Replacements…1
 Why replace ITO?




Brittle & inflexible
Highly reflective (IR = 2.6) & tinted yellow
Costly to pattern & needs high temperature processing
Relies on “environmentally questionable” Chinese zinc mines*
 Replacement material objectives




Better in all of the above characteristics
Higher transmissivity & same resistivity
Solution processing (no vacuum sputtering)
Same or lower cost than ITO
 Three main replacement candidates
 Metal nano-wires
 Carbon nanotubes
 Conductive polymers
* 63% of estimated 2007
production of indium
261
 Metal nano-wires
 Cambrios



Synthesis of inorganic material (e.g., silver) from soluble
precursors, followed by assembly of the resulting materials
into nanostructures
Cambrios has been coating
rolls of PET with their
material (“ClearOhm”) in a
roll-to-roll production facility
since early 2007
Cambrios is working with
all the Japanese resistive
Source: Nikkei Business Publications
suppliers, but has signed
an exclusive agreement for pro-cap with Nissha
 Others

Sigma Technologies, Nanoco, university research
262
C a m b r io s S a m p le T C F ilm
A G / P E T / C lr H C / T C
95
90
85
Transmission, %
PET Substrate
80
Cambrios Film
75
ITO Film
70
65
60
55
50
380
430
480
530
580
630
680
730
780
W a v e le n g th , n m
B a re F ilm u s e d fo r T C
T C 2 5 0 o h m /s q
IT O 2 8 0 o h m /s q
Source: Cambrios
263
 Carbon nanotubes
 Unidym



Merged with Carbon Nanotubes Inc. (CDI) in 2007; IP leader
Targeting touch-screens first, then displays and photovoltaics
Not yet meeting transmissivity & resistivity targets
 Eikos


Mostly funded through government contracts on conductive
polymeric coatings and films (e.g., ESD film, EMI shield, etc.)
Good progress on transmissivity & resistivity but… no momentum
 Others

Canatu, RQMP, DuPont
264
 Conductive polymers (PEDOT/PSS)*
 Fujitsu





* poly(ethylene dioxythiophene) / poly(styrene sulfonate)
The only commercialized replacement so far
First announced in 2003; first production in 2008
5X – 10X touch-screen lifetime
Roll-to-roll film manufacturing
BUT, conventional wisdom is that PEDOT has inferior
transparency and degrades under UV…
 Others

Agfa, Kent Displays, National Starch, university research
265
 Realities




The indium supply is not really an issue
ITO used in LCDs is < 1% of cost (~$4 for a 40” display)
LCD makers are very reluctant to make changes in fabs
Touch-screens provide several good reasons to switch
from ITO to an alternative, but the market is relatively small

500M cellphone touch-screens only need about $5M of ITO
 Flexible displays are probably the biggest opportunity
for ITO replacements, but there’s still no killer app
 Conclusion
 Replacing ITO is unlikely to be a quick activity
266
Appendix-5
Sunlight
Readability
of Resistive
Touchscreens
267
Common Solutions
For Sunlight Readability
 Active enhancement
 Boost the LCD backlight intensity to 1000+ nits


High power consumption
Thick, hot & heavy
 Passive enhancement
 Add brightness enhancement films


Limited to 2X increase in brightness (not enough)
Reduces the LCD’s viewing angle
 Controlling reflections
 Reflected light reduces contrast (that’s the real problem)
 Controlling reflected light is the most effective solution
268
Touch-Screen Surface Reflections
Note: Drawing is not to scale!
S1
Touch Screen
1 - Hardcoat
2 - PET Film
S2
3 - ITO Coatings
S3
4 - Air Gap
S4
5 - Spacer Dots
S5
6 - Glass
7 - LCD Top Polarizer
8 - LCD Cell
9 - LCD Bottom Polarizer
10 - Backlight
LCD
S1
4%
S2
5%
S3
5%
S4
4%
S5
2%
No enhancement
5 AR coatings
0.5% 2.5% 1% 0.5% 0.5%
Total Reflectivity
20%
5%
269
Circular Polarizer Principal
Combination
is Equivalent
to a Circular
Polarizer
Reflection
Right-Circular
Polarized Light
Quarter-Wave
Retardation Film
Linear-Polarized
Light (Horizontal)
Linear Polarizer
Unpolarized Light
Reflecting
Surface
Left-Circular
Polarized Light
Linear-Polarized
Light (Vertical)
Reflection is blocked
Principle: Modify the polarization
of reflected light so it can’t escape
back through the polarizer
270
Touch-Screen Surface Reflections
with Circular Polarizer
S1
1 - Hardcoat
Touch Screen
2 - PET Film
3 - Linear Polarizer
Equivalent
to a Circular
Polarizer
S2
4 - Retardation Film
5 - COP Film or Glass
6 - ITO Coatings
S3
7 - Air Gap
S4
8 - Spacer Dots
S5
9 - Glass
12 - LCD Cell
LCD
S1
4%
0.5%
S2
5%
2.5%
14 - Backlight
S3
5%
1%
S4
4%
0.5%
S5
2%
0.5%
No enhancement
5 AR coatings
Circular polarizer 0.5% 0.1% 0.1% 0.5% 0.5%
+ 3 AR coatings
Total Reflectivity
20%
5%
1.7%
271
Touch-Screen Surface Reflections:
The Ultimate Solution
S1
1 - Hardcoat &
AR Coating
2 - PET Film
Touch Screen
Equivalent
to a Circular
Polarizer
S2
5 - COP Film or Glass
S3
6 - ITO Coatings
S4
7 - Air Gap
S5
8 - Spacer Dots
9 - Glass
Reference:
General Dynamics
Itronix DynaVue
http://www.ruggedpcreview.com/
3_technology_itronix_dynavue.html
11 - LCD Cell
LCD
No enhancement
5 AR coatings
Circular polarizer + relocated
retardation film + 1 AR coating
S1
4%
0.5%
13 - Backlight
S2
5%
2.5%
S3
5%
1%
S4
4%
0.5%
S5
2%
0.5%
0.5% 0.1% 0.1% 0.1% 0.1%
Total Reflectivity
20%
5%
0.9%
272
1% Is Good Enough
 Rule-of-thumb for approximating extrinsic contrast
Contrast Ratio (CR) = 1 + (Display Brightness / Reflected Light)
 In 10,000 nits ambient light, 1% reflected light = 100 nits
 With a 500-nit automotive display, CR = 6, which is good enough
for acceptable sunlight readability
Contrast
Ratio
1-2
3-4
5.5-6
10
15
20
LCD Outdoor Readability
Totally unreadable in sunlight
Adequately readable in shade; barely readable in sunlight
Military spec for minimum acceptable readability in sunlight
Definitely readable in sunlight; looks good
Outstanding readability; looks great
Totally awesome; excellent readability; can’t improve
273
Surface Treatments
 Anti-Glare (AG)
 Changes specular reflections into diffuse reflections
 Changes the form of reflected light but doesn’t reduce the amount
 Formed by etching, abrasion or deposition
Light source
Reflected
light
Anti-glare hardcoat
Without AG
(clear reflection)
With AG
(blurry reflection)
 Anti-Smudge (AS)
 Minimizes the effect of skin oils on the touch panel’s top surface
 Hydrophobic coating; can be combined with AG
274
Surface Treatments…2
 Anti-Newton’s Ring (ANR)
 Prevents Newton’s rings from being formed by contact
between the PET film and the glass substrate
 Texture added underneath ITO coating on bottom of PET
 Adds ~1/3 of the haze value of AG
Without ANR
With ANR
275
What About Projected Capacitive?
Touch Screen
S1
1 - Protective Film
2 - Glass
3 - ITO Coatings
S2
4 - Dielectric (Insulator)
S3
6 - LCD Cell
8 - Backlight
LCD
S1
S2
S3
Total Reflectivity (Resistive)
No enhancement
4% 5% 2%
11%
20%
3 AR coatings
0.5% 1% 0.5%
2%
5%
Circular polarizer
---(N/A)
0.9%
0.5%
Optical bonding + 0.5% 0% 0%
(N/A)
one AR coating
276
Appendix-6
Automotive
Touch
277
Automotive Applications
Can Be Difficult!
Note: Focus here is the center-stack (CSE) “navi-radio” application
 Temperature
 -30°C to +85°C operating
 -40°C to +95°C storage
 Light management
 Sunlight readability

Relaxed requirement for rear-seat entertainment (RSE)
 Crashworthiness
 Top surface can’t be glass (DOT)
 Cost
 Especially important for dealer-installed vs. OEM-installed
 Vibration
 Cables & connectors
278
Automotive Applications
Can Be Difficult…2
 Industrial design
 Narrow frame borders & flush surface
 Usability
 Use with gloves
 Off-angle viewing
 Polarizer used for sunlight viewability can be a problem
 Optical bonding is still too expensive
 Flammability
 Gaskets
 Humidity
 Condensation freezing into ice crystals
 ISO quality requirements
 Difficult for a small or inexperienced company to meet
279
2008 Automotive & Portable Navigation
Device Touch-Screen Market Size
 2008 automotive touch-screen sales (100% resistive)
 Units = 15M (22% glass-glass, 78% film-glass)

4.6% of total resistive; 3.7% of total touch-screen market
 Revenue = $110M

 ASP = $7.37
This average selling price (ASP) should be about 2X-3X
higher; DisplaySearch’s revenue estimate is probably incorrect.
 2008 portable navigation device sales (100% resistive)
 Units = 43M (99.7% film-glass)

12% of total resistive; 11% of total touch-screen market
 Revenue = $155M

 ASP = $3.62
This ASP is about right for a 3” to 4” touch
screen on an aftermarket device ($1/inch).
Data from DisplaySearch
2009 “Touch-Panel
Market Analysis”
280
Automotive & Portable Navigation
Device Touch-Screen Forecast
Unit Forecast 2009-2015
70
Units (Million)
60
50
40
55%
Portable
Automotive
74%
30
20
45%
10
26%
0
2008
2009
2010
2011
2012
2013
2014
2015
 DisplaySearch forecasts that Automotive remains 100% resistive
through 2015, and Portable is only 1% projected capacitive in 2015
Data from DisplaySearch 2009 “Touch-Panel Market Analysis”
281
Appendix-7
Touch Screen
Manufacturing
282
Touch Screen Manufacturing
How Factory and Cost Modeling Can Help
•
Keep track of tools and equipment, and associated parameters
including throughput, depreciation and maintenance costs, and
required personnel
• Separate material handling from process costs, space & throughput
• Keep track of recipes separately from tools to allow mix and match
scenarios and change in process flows
• Keep track of material usage and cost- optimize device size and
configuration to eliminate costly raw material waste
• Be able to vary minor elements and see throughput, cycle time and
yield responses
• Obtain costs per square foot or cost per device
• Compare roll to roll and sheet based costs, space, headcount, tool
sets
• Determine where wind/unwind stations should be located, based on
throughput matching
• Determine impact of design rules and additional devices or layers –
e.g., for in-cell touch
283
Flex Electronics Models
Printed Ink Process
284
Flex Electronics Models
Sputter Laser Process
285
Flex Electronics Models (Typical)
286
Cost Drivers In Flex Displays
and Electronics
1. Two areas emerged as key cost drivers:
1. Materials
2. Product packing density
2. Automation and substrate processing speed has
improved.
3. Devices are being scaled up to narrow webs and larger
flex sheets to conform with the value proposition for the
particular device.
1. Less than 2 foot webs, narrow webs
2. Web on web or Flex piece on web
3. Flex on glass
287
Cost Drivers In Flex Displays
and Electronics
Product packing density
1- High device packing density is needed to achieve low
cost
2- Product engineering must account for
A- Alignment tolerances of multilayer devices
B- Processing tolerances of line-width
3- Design rules for new flex devices in all applications are
still evolving
4- Mechanical and process engineers must work together
and create test patterns and metrics for new device
types
288
Cost Reduction
•
•
•
•
Traditional printers are seeking new markets and have valuable
equipment and process skills
Seek capital equipment and materials suppliers from “least cost
industry”
Impact of ubiquitous RFID will be that roll-to-roll electronic products
will develop low cost techniques - reducing 10x in next 5 years
Convergence with consumer applications and pricing such as
clothing, skin patches, blankets, cell phones, books/ebooks
289
Manufacturing Scale-Up Planning
• Sheet to roll transition – THE BIG STEP
•
Don’t change too many things at once
–
–
–
–
–
–
Product size
Product complexity (minimum geometry, registration, number of layers)
Sheet size to roll size
Tool/equipment type
Process method
Facility conditions: temperature, relative humidity
•
Be sure your material handling and tool suppliers understand the
product geometry and cleanliness required
•
Do a rigorous layout to be sure equipment and support equipment
will fit and be accessible for maintenance
•
Match rates throughout the system based on number of passes use a mathematical model
290
Baseline Existing Processing
• Process parameter optimization and control
• List each process
– Don’t skip even the most “trivial” step
– List off-line support steps (premixing of inks, pre cut of laminated
materials, etc.)
• List associated tools and equipment
• List critical parameters
– Pareto the most critical parameters for each step - work on top 3
– Include
• Observations of products - metrology tools and criteria
• Environmental conditions
• Settings on equipment
• Expected defects and faults
• Know statistical validity of settings and metrics
– How many have actually been produced with a given recipe?
5, 50, 500, 5000
– How consistent were results? Yield (good product)?
291
Touch Screen Manufacturing
Uses PC Board Handling
• 18” x 24” is standard flexible circuit board size, lots of
equipment is available in this format.
292
Vision of the Roll-to-Roll Line
• Clean
• Automated
• High yield
Facility
Materials
Tools
293
Baseline Existing Materials
• Materials Control
• The product will never be better than the materials you start with
• Know your vendors
–
–
–
–
Who supplies them?
What percentage of their volume does your product represent? Now? In a year?
Can they ramp fast?
Does your product push the statistical control of their product specification? Do the
distribution of requirements overlap? Is there a guard band?
– Have a relationship with at least 2 suppliers for each critical material
• Keep looking, don’t give up
• What new features in the materials would make your next steps easier?
How can you evaluate these NOW?
• Can you and are you identifying lots, batches of material?
• Do you understand how your suppliers manufacture and qualify their lots?
• How do you plan to qualify /trace materials in your line?
Risks of multiple simultaneous qualifications are
multiplicative if not exponential!
Mass markets tolerate few glitches in supply!
294
Baseline Existing Processing
• Device tolerances
• Define critical parameters
– Establish a realistic tolerance for each
– Add up cumulative tolerances - draw out and review any
cumulative mechanical tolerances
– Plan for iterative product design
– Create guard bands for all critical tolerances and most
secondary tolerances
• Define tolerances for each tool/equipment
• Verify that cumulative tolerances match: Device to
equipment
• Registration Registration Registration
295
Make Alignment Keys with Metrology
1st Layer:
Initial Pattern
2nd Layer:
Perfect!
3rd Layer:
Misaligned
Image enhanced to show misalignment.
296
Importance of Design Rules in
Creating Manufacturable Products
297
Importance of Design Rules in
Creating Manufacturable Products
• For cost reduction, reexamine design rules to see where
more efficient use of substrate gives more product per
substrate
• Caveat: Experiment to understand tolerances FIRST! For
flexible substrates, registration tolerance is key. Highdensity product layout beyond registration tolerances will
be very low to 0 yield.
• Iterative Process: Each version of tooling should have
test patterns to help determine future improvements in
registration and packing density
298
What is Critical in Device Design Rules?
Optical Waveguide Touch Example
Are any of these
critical?
Distance from1 to 2
Location 1
Location 2
Distance from 2 to 3
Distance from 1 to 3
Location 3
Area A
Gap B
Area C
Are any of these critical?
Width of Area A or Area C?
Width of Gap B?
What do you call?
Area A or C?
Gap B?
299
Process and Tool Evaluation: What Defect
Density Is Tolerable? What Is a Defect?
• Measure defects on good
and bad product
• Keep inspection data
• Try out different types of
inspection equipment
Vendor 1
Vendor 2
Vendor 3
300
Testing Equipment – Often Overlooked
Is This Test Setup Ready for Scale Up?
• Common problems
– No fixed test-beds
– No “golden unit”
– Lack of data storage
– Lack of trend analysis
301
What Kind of Facility Space is Needed?
•
Clean Class
– Class 10; 100; 1,000; 10,000; 100,000
– Most Costly Decision
• Impacts
–
–
–
–
–
Air Changes and Treatment
Quantity Filters
Quality of Filters (ULPA vs. HEPA)
Types of Construction Materials
Cost of Ownership
– Understanding the Process and Geometries
will help in selecting the appropriate clean
class
– Providing the right combination of clean class
by area can satisfy user needs and reduce
costs.
Photo Bay
Class 100
Thin Films
Class 1,000
302
Cost Drivers
• Height
– Height affects volume of clean space
• Volume impacts how much air has to be treated and recirculated
– Keeping ceiling heights to a minimum can be a cost savings
– Requirement for air handling space above ceiling must be
considered
– Process tools get taller with larger substrates
303
Cost Drivers
• Single Pass Air
–
–
–
–
Very Costly
Conditions air once and sends to exhaust
Does not take advantage of recirculation of conditioned air
Some spaces may require single pass air by code
• Humidity Control
– Humidity affects process and equipment
• Understand what levels are damaging to the process
• Understand what tools are sensitive to humidity
– Local climate may drive the need to add or remove humidity
– Some climates may not require any humidity control
304
Cost Drivers
• Use of Hazardous Productions Materials (HPM)
– Quantities directly affect hazardous occupancy rating
• “H” Occupancy vs “B” Occupancy
• Exceeding maximum allowable quantities can force the space to
become an “H” Occupancy
• Drives Construction Materials Cost
• Use of flammables such as Acetone (Class 1B) can drive higher
Hazard Occupancy
305
How Clean Does My Cleanroom Need
To Be? Know the Expensive Answers
Clean Room Cost Assumptions
$/Sq Ft
Class
Add for
Raised Floor
Add for
Subfab
$2,100
1
Required
Required
$1,425
10
Required
$600
$1,205
100
~$160
$600
$900
1,000
~$100
$400
$700
10,000
Not Needed
Not Needed
$75
Support
(Facilities)
N/A
N/A
Cost does not include specialty piping or tool hookup
306
Low Sidewall Return
• Least expensive
option because it
doesn’t require a
raised floor
• Least flexible
because space
must be left in the
wall for air flow
• Higher pressure
drop across
smaller wall
openings requires
more fan energy
• Limits width of bay
to 12’ – 14’ for
good laminarity of
air flow
307
Lay Out Space for Maintainability
• Think about
maintainability
when linking
several
processes in a
roll to roll line
Lamination Process Station
308
Use Vertical Space Wisely
• Multilevel roll-to-roll lines are
common
• Cleanliness and maintenance
need to be planned
309
Touch-Screen Line Costs
• Line price and product
price expectations similar
to printing industry
• Key process steps differ
• Collaboration is productive
310
Technology Improvement
Recent Accomplishments
• Web handling control and
alignment of patterns and layers
• Improved cameras and optics for in-line
data collection and immediate response
alignment of web
• Improved web handling mechanisms
• Temperature and RH controlled
environments
311
Technology Improvement
Recent Accomplishments that Benefit New Applications
• Sophisticated inks, fluids and gels with both electronic
and physical properties
– Inks with electronic properties
– Gels with various methods of cure to seal temporarily,
permanently
– Viscosity control of inks and gels by temperature and
RH control
– Transparent organic conductors and semiconductors
• Substrates and surfaces with engineered properties to
facilitate product design or process.
– Temperature “hardened” to minimize shrinkage
– Impregnated with Aluminum Oxides for
translucency/opacity
– Polished surfaces to reduce defects
– Moisture barrier coatings
– Punched, laser drilled and formed surface cavities
• Inlays for small “semi flexible” applications
– Credit cards with chip/display/battery/interconnect
312
AGI Modeling Suite and Services
Visit www.abbiegregg.com for software demos.
And visit AGI at Booth 2406 in the South Hall to
learn more about our services and expertise.
313

Fundamentals of Touch Technologies and Applications

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