Flexible OLED Displays

Chua Pei Pei Pauline - A0098566J

Sneha Shashi Kumar - A0102912W

Chan Yue Ming - A0098453U

Edwin Gerard Lam - A0098404B

Nivali Chenreddy - A0102885A

Introduction to Flexible OLED

Challenges of Flexible OLED

Materials & Process - Improvisation

Opportunities for Flexible OLEDs

Conclusion

Evolution of Display Technologies

Lumpish CRT to Flexible Display – Source - http://jilinudt.com/english/Solutions.html


Introduction to OLED

Substrate

Anode layer

Organic layers

Cathode layer

Encapsulation layer

An OLED (organic light-emitting diode) is a light-emitting diode (LED) in which

the emissive electroluminescent layer is a film of organic compound which emits

light in response to an electric current.

Layers of OLED


Basic Principle of OLED

1) Cathode (-)

2) Emissive Layer

3) Emission of Radiation

4) Conductive Layer

5) Anode (+)

The flow of light emission can be illustrated by the concept of a person

going down the big slide.



Parameters OLED LCD

Color Brightness & Contrast

Comparison with OLED and LCD

Black Point/ Turning Pixels Off

Incredible Contrast

Introduction to Flexible OLED Source: http://www.smallhd.com/products/ac7/oled-vs-lcd-on-camera-field-monitors.html


Parameters OLED LCD


Power Consumption

Viewing Angle

No constant burning backlight in OLED technology

Viewing Angle of 165°

Lower Power Consumption

Better View Angle


Introduction to Flexible OLED Source: http://archive.siliconchip.com.au/cms/A_30650/article.htm


Parameters OLED LCD


Power Consumption

Viewing Angle

Cost

Source: OLED-Info, Aug 9,2012

Relative Cost difference between LCD, White OLED and Red-Green-Blue OLED

Producing large OLED panels is still very expensive - low yields and high material costs.

OLED Lighting

LCD

OLED Displays




Parameters OLED LCD


Power Consumption

Viewing Angle

Cost

Lifespan

Lifespan

LCD OLED

60,000hrs Red – 46,000hrs, Green – 2,30,000hrs, Blue – 14,000hrs

Source: http://www.differencebetween.info/difference-between-lcd-and-oled




Flexible OLED is a type of organic light-emitting diode (OLED) incorporating a flexible plastic /glass substrate on which the electroluminescent organic semiconductor is deposited.

How is flexible OLED different from OLED?? Flexible substrate Electrode material Encapsulation process



Concept Video- 3M Flexible Display


Roadmap for Flexible Display

Source: http://www.3neo.org/rs/297/d112d6ad-54ec-438b-9358-4483f9e98868/e70/filename/workshopmadrid-cros.pdf

Resolution Lifespan Area







Conclusion

Challenges of OLED

Challenges of Flexible OLEDs

Efficiency

Lifespan/ Reliability

Large Area Devices

Cost

Challenges of OLED





Conclusion


Material & Process - Improvisation

Substrate

Lifespan

Electrode

Cost of Manufacturing

Bigger/More Fabrication

Plants

Improving Materials

Improving Process

Materials & Process


OLED Material Cost Targets

Source: http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/maikowski_enablers_longbeach2013.pdf

Integrated Substrate < $52/sq.m Organics < $10/sq.m Encapsulation < $20/sq.m

Target by 2015

Integrated Substrate

Materials Improvisation


Flexible Substrate

Properties of Flexible Substrates:

Flexibility – Stiffness vs. Thickness

Mechanical, Thermal, and Dimensional Stability

Surface Roughness & Optical Transparency

Moisture Absorption

Properties Polymide PEN Flexible Glass

Max Process Temp (0C) 350 180 600

Transparency Low Good Excellent

Surface Roughness Medium Medium Excellent

CTE (ppm/0C) 16 40 5

Moisture Absorption Low Medium None

Cost Medium Medium High

CTE – Coefficient of Thermal Expansion

Depends on various applications



Flexible Substrate - Thickness

Source: Corning_AIMCAL_2011.pdf

As the thickness of the glass decreases it becomes more flexible. Polymer has less stiffness even though if the thickness of it is high comparatively.



Varied Thickness allows different type of applications.

Schott – 25 & 50 µm thick Flexible glass Nippon Electric Glass – 100 µm thick Flexible glass Corning – 50 -200 µm thick Flexible glass

Flexible Substrate - Mechanical Reliability

When a glass of thickness 50µm is bent at some radius the Stress on the glass is lower than 500µm or 100µm. The failure probability is low when the glass is thinner and can be made more flexible. Need of Ultra thin glass for the substrate.



Source : Corning_AIMCAL_2011.pdf - www.corning.com/WorkArea/downloadasset.aspx?id=48957

Flexible Substrate - Thermal & Dimensional Stability

Flexible Substrate benefits

Device Fabrication

Thermal Stability

Dimensional Stability

Source : Corning_AIMCAL_2011.pdf - www.corning.com/WorkArea/downloadasset.aspx?id=48957

Thermal & Dimensional Stability

Glass exhibits same Stress & Strain at 250C and 1500C when compared with PEN & Polymide. At higher temperatures Glass does not change it shape or size but Plastic has distortions.



Glass is more thermally & dimensionally stable compared to plastic substrates

Flexible Substrate - Device Performance Optimization

Source: Corning_AIMCAL_2011.pdf - www.corning.com/WorkArea/downloadasset.aspx?id=48957

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Glass exhibits less surface roughness compared to others

Glass - Transmission of light is more



Flexible Substrate Benefits Device Performance Surface Roughness Optical Transmission

Ultra Slim Glass, Plastic & Rigid Glass Substrates

Source: 2012 SID Exhibitor Forum (Dipak).pdf

Advantages

Over Thicker Glass: Over Plastic:


More Flexible 7 x reduction in weight 7 x reduction in thickness ~50% process cost reduction by R2R

Perfect Barrier Superior Surface Quality ~7% Better transparency High Temperature processing >500 oC


Cost of Glass & PEN Substrates

Source: http://fennagain.wordpress.com/2013/03/29/ito-and-flexible-glass-substrates-3/

Target Price for Flexible Glass - $20 per sq.m PEN Substrate : $ 8 – 10 per sq.m

Popular Glass Substrates Manufacturers for Displays



OLED Lifespan challenge

OLED degrades overtime due to: Intrinsic degradation of organic polymer - More stable and efficient molecules needed - Requires a barrier to prevent the flow of water or gas entering. Electrode oxidation - Requires a barrier to prevent the flow of water or gas entering Black spots caused by permeation

Black spots grow in time Source : HolstCenter – Future of Flexible OLEDs



Ultra-good barrier needed

Very low permeation rate in flexible OLED:

- 10-6 g/m2/day of WVTR

- 10-6 to 10-3 cm3/m2/day of OTR

Increase Lifespan by 10,000 hours

Barriers in production: glass or metal flip

Source : HolstCenter – Future of Flexible OLEDs



Barriers in OLED is 1 million times stronger than typical package of a potato chips!

Permeation rate of different Substrates

Source: IDTechEx

WVTR – Water Vapour Transmission Rate, OTR – Oxygen Transmission Rate Water Vapor and Oxygen Transmission Rates of various materials

used as Substrates

Material WVTR g/m2/day OTR g/m2/day

PET 3.9 – 17 1.7 - 7.7

PEN 7.3 3.0

15 nm Al/PET 0.18 0.2 - 2.9

SiOx/PET 0.007 – 0.03

ORMOCER/PET 0.07

OLED Requirement 10-6 10-6 to 10-3



Comparison of Different Barrier Type

Barrier Type WVTR g/m2/day

OTR Cm3/m2/day

Strengths Weaknesses

Polymer (no barrier)

10-1 to 102 10-1 -10 Excellent clarity Flexible and tough

Expensive Low performance WVTR can change abruptly

Ceramic Coated Polymer

10o – 10-2 3x10-1 Good Clarity Somewhat flexible

Brittle in tension Cannot creased

Multilayer Ceramic coated polymer

10-3 – 10-6 10-1 – 10-4 Good Clarity Somewhat flexible

Brittle in tension Cannot creased High cost for > 2 layers

Glass zero zero Transparent Scratch resistant

Not used in Roll- to- roll

Source: http://www.flexcon.com/Resource-Center/~/media/Files/PDFs/Website/Resource%20Center/White%20Papers/Combining%20Barrier%20Technology%20with%20Other%20Important%20Properties%20in%20Flexible%20Electronics.ashx



Lifespan using Multilayer Ceramic Film

Multilayer Film – Single Material Up to 3 dyads of SiOx/Parylene

Multilayer Flim – Different Materials SiOx/Al2O3/Parylene SiNx/Al2O3/Parylene

Source: http://www1.eere.energy.gov/solar/pdfs/pvrw2010_graham.pdf > 7500 Hours > 7500 Hours



Flexible Electrode Material

Indium Tin Oxide (ITO) - Current

Graphene Electrodes (G) –

Future

Brittle & inferior flexibility

Resistance increases at low temperature

Expensive to integrate into displays

More flexible and higher efficiencies

Fabrication & processing cost is high and complicated


Improvement for Electrode (Anode and Cathode layer) Transmittance Luminance Efficiency


Electrode Transmittance

Source: http://ec.europa.eu/research/industrial_technologies/pdf/graphene-presentations/0-3-ferrari-21032011_en.pdf

Graphene films have higher Transmittance over a wider wavelength range with respect to SWNT films, metallic films and ITO



Electrode - Luminous Efficiency

Electrode Luminance Efficiency (lm/W)

Graphene (4L – G-HNO3)

102.7

ITO 85.6

Source: http://home.skku.edu/~femlab/publications/2012/nphoton.2011.318.pdf

Luminance Efficiency of Phosphorescent OLED

Graphene Electrode has higher luminous efficiency than the ITO electrode and hence the better.



Price of ITO (Electrode material)

Source: http://www.bishop-hill.net/blog/2012/3/9/running-out-of-natural-resources.html

~$600 /Kg



Price of Graphene (Electrode material)

Graphene meets electrical and optical requirements The fracture strain of graphene is ten times higher than that of ITO. Advantages over ITO – Mechanical flexibility, chemical durability, good barrier

Chemical Vapour Disposition Process


$ 1K – 99K per Kg ( quality vs. price)

Roll to Roll – mass production has potential to reduce operational costs by 70-80% at scale

Source: A roadmap for graphene - http://lib.semi.ac.cn:8080/download/2012/11/15/110603.pdf http://www.ornl.gov/adm/partnerships/events/Dec_Spark/Speight_Graphene%20v5.pdf http://www.alibaba.com/product-gs/825094072/Graphene_chemical_.html http://arxiv.org/ftp/arxiv/papers/0912/0912.5485.pdf

Active Matrix OLED

Passive Matrix OLED

Roll to Roll Process Cost

Lower the cost of manufacturing of display Cost per square foot of OLED are expected to decline with increase in volume

Minimum Efficient Scale – 20,000 square feet Achieve a cost of $74 per square feet at a capacity of 100,000 square feet

per week Source: http://people.ccmr.cornell.edu/~cober/mse542/page2/files/Flex%20Manufacturing%20Concepts.pdf

Projected Cost AMOLED - $74 per sqft

Process Improvisation


Future Fabs for Flexible OLED Displays

8-Gen (2200x2500mm) fab & 6.5 Gen fab – AMOLED displays

3.5-Gen (730 × 460 mm) flexible OLED production line.


Pilot/Mass Production Plants in next 2yrs:






Conclusion


Flexible OLED Ecosystem

OLED Display Makers

Opportunities for producing AMOLED and PMOLED displays

Opportunities for Flexible OLED


Chemical Companies Produce materials used in OLED production-emissive layers, transport layers, conductive inks, doping materials etc.

Manufacturing Equipment Develop research and production of OLED equipment

Flexible OLED Ecosystem

Research/ IP Companies

OLED Research and Technology services



OLED Retailors Sales of display, modules and other services

OLED Lighting OLED is set to revolutionize the lighting industry with all small and big players

Complementary Opportunities to Flexible OLED

Stretchable Batteries Flexible Electronics



From flexible to conformable

For 3-D surfaces

Platform for large area conformable electronics

Could this be the future??



Applications: Prototypes and Products Opportunities for Flexible OLED

Samsung, Microsoft

• Hype on new ‘Youm’ Flexible OLED display

Sharp

• Flexible OLED prototypes

Sony

• "Rollable" OTFT - driven OLED Display that can wrap around a Pencil


Applications - Navigation or Military

Navigation

Maps (or even photo albums) could be made from bendable media cards

Military

Researchers at HP are expected to deliver a Dick Tracey wrist watch to the US army



Applications: Ultra Thin Rollable OLED

Flexible OLEDs can be manufactured akin to newspapers on a printing press

Creating innovative pens with displays



Other Applications

Manufacturing car roofs, car tails and car windows

Designing OLED costumes

Headsets with OLEDs







Conclusion

Conclusion

Entrepreneurial Opportunities

Conclusion

Substrate

Electrode

Lifespan

Cost of Manufacturing

Bigger/More Fabrication Plants

Conclusion

Flexible OLED Challenges of Flexible OLED

Materials & Process Improvisation

Opportunities for Guys…

Flexible OLED Displays

Business

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