SID Display Week 2012 presentation given by Paul Cain, Senior Manager, Technology, at Plastic Logic.

1. Flexible Colour Active Matrix EP
Display Using Low Distortion
oTFT Backplanes
Paul Cain
7th June 2012

2. Speaker Introduction
Flexible Colour Active Matrix EP Display Using Low
Distortion oTFT Backplanes
Paul Cain, PhD CEng
Senior Manager, Technology
Plastic Logic, Cambridge UK.
• Over 10 years at Plastic Logic
• Focus on novel processes, device architectures, new technology integration
• Technology Transfer to Dresden Production Facility
• Over 20 patents / applications
• PhD Physics (Cavendish Laboratory, Cambridge University)
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3. Plastic Electronics Technology
Uses plastic instead of traditional silicon semiconductors
and glass
Enables a revolutionary design and form-factor
Shatterproof, Thin, Large and Light Display

4. Company History
Display Development
10+ transistors 100+ transistors 1.2 M transistors Colour EPD 2.8 M transistors
Research, Process Development & Manufacturing
2000: Cambridge Technology 2008: Dresden Display Factory
Cambridge University Center translating research First plastic electronics factory in
Research in organic electronics into products the world
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5. The Manufacturing Challenge
It is one thing to show a single display at a tradeshow…
...quite another to develop a high yield manufacturing process
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6. R&D and Production Set-Up
Technology
Transfer
Cambridge R&D
Prototype Line (14”)
Cambridge R&D Prototype Line
 Proof of concepts
 Highly configurable process
 New designs in < 1 month
 1” Chips to A4 displays
 R&D Engineers
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7. R&D and Production Set-Up
Technology
Transfer
Dresden Factory (Gen 3.5)
Dresden Gen. 3.5 Factory
 Backplane Manufacturing
 Qualified volume process
 Production equipment
 Fully Automated Handling
 Process, Equipment, Integration
Engineers
 Thousands of displays/week
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8. Electrophoretic Plastic Display
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9. Electrophoretic Display Media
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10. Distortion
Flexible substrate
GLASS RIGID CARRIER
 FPD industry processes designed assuming glass substrates
 Processing on flexible plastic:
 Dimensions affected by temperature, humidity
 Irreversible and reversible components.
 Multiple methods used to reduce distortion
 Low temperature processing
 Reduced thickness flexible substrate
 High Tg substrate material (eg PI)
 Trade-offs with each approach
 Plastic Logic approach re-sets distortion by design, without losing pixel
performance:
 Common substrates to be used (eg PET)
 Mounted or un-mounted plastic substrates (eg Roll to roll)
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11. Low Distortion Backplane - Design
Pixel
 Conventional glass Electrode
backplanes require regular
grid for all layers
Interlayer
(source, drain, gate, via, etc Via Dielectric
)
 This allows overlay of pre-
patterned layers (eg Colour
Filter)
 Distortion in flexible
substrates makes this
difficult
 Plastic Logic Process resets
distortion at the pixel
electrode layer, with no loss Plastic Backplane: Top Pixels
Glass Backplane: All stack
in pixel performance. layers on a regular grid maintained on a regular grid
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12. Low Distortion Backplane - Measured
 Backplane distortion measured
 OGP Vantage coordinate  Measurement Area 217.6mm x
measurement system used 163.2mm
 Distortion controllable to < 5um in  150 PPI Backplane
production.  100 point sample
 Maximum measured deviation
 ∆X [-2.3, 1.8] µm
 ∆Y [-3.1, 4.1] µm
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13. Colour EP Display Architecture
Encapsulation sheet Colour Filter Array
Plastic Substrate
E Ink Frontplane
Plastic Logic Backplane Technology
Low Distortion Plastic
Plastic Substrate Logic Backplane
 Colour Filter patterned by multiple approaches (wet printing, sheet-to-sheet
alignment).
 During CFA pattern formation, the backplane pixel electrodes are not
visible (obscured by E Ink layer).
 Backplane:
 1280 x 960 pixels (monochrome) = 640 x 480 Colour
 150PPI (monochrome) = 75PPI Colour
 Active Area: 217.6mm x 163.2mm
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14. Colour Filter Overlay
 RGBW colour filter patterned onto E Ink surface
 Overlay accuracy of 10µm achieved across the active area
 Four variants of different colour density investigated
RGBW CFA pattern over E Ink R pixels driven “white” to show alignment
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15. Colour Display Performance - Gamut
 4 colour densities tested
(A,B,C,D)
 Gamut (∆E3):
 Type A: 5000
 Type B: 4000
 Type C: 3400
 Type D: 3000
 Excellent colour
uniformity, viewing angle
Acknowledgement: A. Bouchard, E Ink
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16. Colour Display Performance - White
Acknowledgement: A. Bouchard, E Ink
D
C
B
Type A
 25% white state reflectivity achieved
 No compromise in optical performance over glass colour filters / backplanes.
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17. Colour Display Performance
Display size 10.7”
Backplane subpixel resolution 1280 x 960
Subpixel pitch 170um (150subPPI)
Backplane Grey Levels 16
NTSC 2-5%
Contrast Ratio 12:1
Reflectance 50-57 L*
 Good white state maintained whilst achieving useful colour gamut
 Excellent contrast maintained due to excellent black state.
 Colour uniformity good across 10.7” display area.
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18. Colour Display Performance
Display size 10.7”
Backplane subpixel 1280 x 960
resolution
Subpixel pitch 170um
(150subPPI)
Backplane Grey Levels 16
NTSC 2-5%
Contrast Ratio 12:1
Reflectance 50-57 L*
 Excellent readability maintained
 (High contrast)
 Colour gamut high enough to
enable distinguishability
 Paper-like finish for the colour
display (no glass layer above the
display)
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19. Process enables higher resolutions….
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20. Summary
 We have developed a new approach to manufacture low distortion
flexible plastic displays:
 Compatible with lower cost substrate materials,
 Process qualified for production,
 Allows integration with a wider range pre-pixelated materials
 We have shown 75 PPI 10.7” colour displays using this qualified
process
 Measured performance equivalent to glass EPD colour
 Visual performance enhanced due to absence of glass colour
filter.
 For demonstrations of our technology, including colour please visit
the Plastic Logic YouTube Channel:
http://www.youtube.com/user/PlasticLogic
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21. http://www.plasticlogic.com
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