Transcript Cleartek II Capacitive Touch Screens

3M Touch Systems
ClearTek II Touch Screen
© 3M 2007. All Rights Reserved
3M CONFIDENTIAL
3M Touch Systems
ClearTek II Touch Screens - Construction
Proprietary ScratchResistant Top Coat
ClearTek Hard Coat with Anti-Glare
Electrode Pattern
Conductive Coating
Glass
• All glass touch screen with transparent,
thin-film conductive coating applied to surface
• A narrow electrode pattern is printed along the
edge of the conductive layer
• Transparent glass hard coat with anti-glare
properties is fused over the conductive coating
• Proprietary scratch-resistant top coat added
• Tail design with solder-less connection and
taped strain relief
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© 3M 2007. All Rights Reserved
3M CONFIDENTIAL
3M Touch Systems
ClearTek II - Tail Design
•Tail has 4 corner wires in a copper layer
• It also has a conductive shield – top & bottom
• This is connected to pin 3 of the controller
• This shield protects the 4 corners from EMI interference
• Insulation layer protecting the shield layers
• The insulating layers protect the shield from shorting out
• During integration, ensure no sharp metal edges can do not
contact or rub against the outside insulating layers of the tail.
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© 3M 2007. All Rights Reserved
3M CONFIDENTIAL
3M Touch Systems
Standard Touch Screen Configurations
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3M CONFIDENTIAL
3M Touch Systems
Serial Number Label Information
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3M CONFIDENTIAL
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Example of a Serial Number Label
 Example of 14 digit serial number – NA170611300126
 AAAA – NA17 – Machine ID #
 YY – 06 – Year Manufactured 2006
 MM – 11 – Month Manufacture 11 or November
 DD – 30 – Day Manufactured 30
 SSSS – 0126 – Sequence # for the day
 Manufacturing date – Nov 30, 2006; 126 touch screen of the day
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© 3M 2007. All Rights Reserved
3M CONFIDENTIAL
3M Touch Systems
Scratch Resistance – Mohs Scale
The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals
through the ability of a harder material to scratch a softer material. It was created in 1812 by the
German mineralogist Friedrich Mohs and is one of several definitions of hardness in materials
science.
Hardness
7
Mineral
Absolute Hardness
10
Diamond
1500
9
Corundum
400
8
Topaz, Hardened Steel
200
7
Quartz, Garnet
100
6
Orthoclase Feldspar, Glass, Iron Pyrite
72
5
Apatite, Knife Blade
48
4
Fluorite, Platinum, Iron
21
3
Calcite, Copper
9
2
Gypsum, Finger Nail, Gold, Silver
2
1
Talc
1
© 3M 2007. All Rights Reserved
3M CONFIDENTIAL
3M Touch Systems
How Does Capacitive Work
 Voltage source (V) applied to surface
 Amplifiers (A1 – A4) measure current &
gain from the corners.
 When a touch occurs a new circuit is
introduced.
 Current is drawn from the touch screen,
through the person, to ground.
 The Ratios of the current in each
corner is used to calculate the position
of the touch.
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© 3M 2007. All Rights Reserved
3M CONFIDENTIAL
3M Touch Systems
Linearization
 Non-linear areas of the touch screen

Raw glass

Conductive coating

Resistance of the border pattern
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3M Touch Systems
Linearization Process
 Linearization corrects non-linearity of the
glass, conductive coating process,
electrode pattern process
Measured Data X&Y
 Linearization compares measured data
points to ideal data points.
Ideal Data X&Y
Before linearization
 Comparison generates correction
coefficients for X & Y position.
 Correction coefficients are stored either in
the controller or with the touch screen.
 Each touch screen has unique correction
coefficients, Novram or mated controllers
should not be separated from the touch
screen it was paired with.
After linearization
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© 3M 2007. All Rights Reserved
3M CONFIDENTIAL