Plastic Logic Flexible Colour Display


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Emerging Display Technologies Conference 2012 presentation given by MIke Banach PhD, Senior Research Manager at Plastic Logic.

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Plastic Logic Flexible Colour Display

  1. 1. Flexible Colour Active Matrix EP Display Using Low Distortion oTFT Backplanes
  2. 2. 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
  3. 3. Company History Display Development10+ 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 3
  4. 4. 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 4
  5. 5. 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 5
  6. 6. The Manufacturing ChallengeIt is one thing to show a single display at a tradeshow…...quite another to develop a high yield manufacturing process 6
  7. 7. Plastic Logic’s Manufacturing Process• Key differences in manufacturing organic and flexible electronics: Solution processing Direct-write fabrication techniques to avoid mask-alignment Low process temperatures to permit use of cheap flexible substrates• Developed unique process know how and IP: Handling plastic sheets throughout the process line Large area deposition technologies of organic and inorganic materials Cleaning and conditioning of the layers to improve device performance• Industrialisation means: Reproducibility Homogeneity 327.0-328.0 326.0-327.0 328.0 325.0-326.0 327.0 324.0-325.0 326.0 590 323.0-324.0 325.0 585 322.0-323.0 324.0 580 321.0-322.0 323.0 322.0 320.0-321.0 575 321.0 319.0-320.0 570 320.0 319.0 565 60 62.5 65 560 67.5 70 72.5 75 77.5 555 80 82.5 85 87.5 90 92.5 550 95 97.5 100 7
  8. 8. Processing challenges in development phase Optimising process conditions is critical part of industrialisation processMonitoring data from coating process in the first year (2009) Thickness mean Monitoring data from same process one year later Thickness mean 8
  9. 9. Display Testing and Reliability Testing requires precise handling and alignment of flexible displays Test development for transistor and display parameters − Definition of test specifications − Electrical and Optical tests for production − Test methods for OTFT and other characterisation structures Reliability optimization for quality and lifetime behavior − Accelerated test under different environmental conditions for lifetime projections − Based on existing models for Si-based integrated circuits − Parameters adapted to organic materials in terms of temperature sensitivities and reaction to cycling 9
  10. 10. Reliability challenges in development phase Reliability problem solving was critical part of industrialisation processTypical problem in early development (2009) Problem solved Delamination during climatic tests Today, Plastic Logic displays have been stressed beyond 10M updates 10
  11. 11. Technology Position Today  Developed the lightest, most durable display technology available today  Demonstrated scalability in the first and largest production facility  Developed the first flexible colour display  Protected with a strong IP position – 101 patents and applications – 36 granted to date  1-2 year lead over the competition for flexible backplane technology  A single display has 1.2M uniform and reliable plastic transistors 11
  12. 12. Thin, Light, and Robust 12
  13. 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 13
  14. 14. Low Distortion Backplane Pixel Conventional glass Electrode backplanes require regular grid for all layers (source, Interlayer 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 in pixel performance. Plastic Backplane: Top Pixels Glass Backplane: All stack layers on a regular grid maintained on a regular grid 14
  15. 15. 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 15
  16. 16. 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 16
  17. 17. Flexible Displays: Now Available Display size 1” - 10.7” Backplane Grey Levels 4 – 16 Pixel pitch up to 225ppi Contrast Ratio 12:1 Thickness thin as 130 µm Weight down to 11g Colour Available NTSC 2-5% Paper-like finish Excellent readability Colour gamut high enough to enable distinguishability Bistable enables long battery life 1280 x 960 Colour Display 17
  18. 18. Plastic Logic Technology in Action • 10 to 12.5 frames per second video on e-ink with colour filters • Driven with 20 sub-frames to maintain voltage across e-ink. • Backplane driving at 200 to 225fps 18
  19. 19. Plastic Logic’s Displays• Plastic Logic is a flexible display OEM and technology provider. We can supply displays in variety of sizes and resolutions and enable others to do so through licensing arrangements.• Plastic Logic is a global leader in OTFT devices and the challenges of manufacturing on plastic.• Plastic Logic is actively looking to partner with companies who can open up new markets for our display technology. 19
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