Flexible Displays and E-paper

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Flexible Displays and E-paper Maxim
Dolgobrod Advanced Display and Image Technologies
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Contents

• What are flexible displays
• Current status
• Development roadmap
• Challenges
• Market
• Main technologies
• Application
• Future
• Conclusion

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What is a flexible display?
Flexible displays are essentially very thin
display screens that can be printed onto flexible
or stretchable material and then attached to
other surfaces or produced in a variety of shapes.
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Flexible display

• Ultimate flexible display is a combination of
  TFT-LCD and OLED techniques with advances
  developed in various fields such as processing,
  component, and materials.
• Display might not be flexible in its application
• Core materials
• semiconductor material
• insulation material
• electrode material
• substrate

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Substrate

• substrate is critical to flexible displays
  development
• different types of materials are under
  investigation, including glass, plastic, polymer
  films, and metallic foils
• must be readily bendable and rollable
• must accommodate different types of display
  technologies at high levels of brightness,
  contrast ratios, and resolution
• must offer low power dissipation
• should be able to provide full-color capability
  to enhance their market acceptability

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Current status

• There is a considerable research
• Most of technologies are still in development and
  available in form of prototypes
• The display panel itself is only a small part of
  the battle. All the ancillary electronics, the
  power, transistors and circuitry are all things
  today that are not yet fully flexible at large
  scales.
• Industry interest and competition is fierce
• The Flexible Display Center, at Arizona State
  University flexible displays ready for test
  trials in approximately 3 years.
• Currently E Ink one of most popular technologies
  available for commercial use

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Flexible displays roadmap
Source Displaybank, 'Flexible Display Technology
and Market (20072017)' report
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Challenges

• From traditional rigid substrates to flexible
  substrate
• Satisfy the requirements of both substrate and
  deposited electronics
• Handle the high processing temperatures
  encountered when making rigid displays
• Laminate adhesives that can perform reliably at
  high temperatures without being affected by
  stresses
• Achieving large quantity supply with comparative
  low cost

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Flexible displays market - demand forecasts
Source Displaybank, 'Flexible Display Technology
and Market (20072017)' report
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History

• 1970 Electronic paper first developed at Xerox's
  Palo Alto Research Center
• 1990 Printing of OLED on flexible substrate
  discovered
• 2000 World's first flexible display using
  electronic ink from E Ink Corporation
• 2002 Philips finds way to 'paint' LCD screens
• 2007 First production-ready flexible display
  manufacturing method developed by FlexiDis, a
  European-Commission funded technology project
• 2008 Hewlett-Packard and Arizona State
  University introduce a prototype of a
  paper-like, flexible computer display made almost
  entirely of plastic

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Main flexible display technologies

• Flexible LCDs
• FOLED, Flexible AMOLED
• E-paper Electrophoretic, Cholesteric LCDs,
• Electrowetting Displays (EWD), Electrochromic
  Displays
• Interferometric Modulator Technology

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Flexible LCDs

• Many display experts believe LCDs are most likely
  to succeed in large-scale, cost-effective
  flexible displays
• Samsung prototyped 5-in. diagonal LCD panel that
  uses amorphous silicon TFTs.
• Fujitsu has shown monochrome and color
  cholesteric LCD, flexible, 3.8-in. diagonal
  panel.
• Pixel-isolated LCDs for enhancing a flexible
  LCD's mechanical stability

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Flexible LCDs
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FOLED

• Organic light emitting device (OLED) built on a
  flexible base material, such as clear plastic
  film or reflective metal foil, instead of the
  usual glass base.
• Developed by Universal Display Coporation
• Started in 1990s after discovery by research
  partner at Princeton University that
  small-molecule OLEDs could be built on flexible
  substrates

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FOLED
Source Universal Display Corporation
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FOLED developed by Universal Display Corporation.
Passive matrix display 0.175 mm thick sheet of
plastic, resolution of 80 dpi 64 levels of grey
scale can show full motion video. Credit
Image courtesy of Universal Display Corporation.
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FOLED

• Pros
• Brighter than LCDs
• Wider viewing angles and faster response times
• Don't need a backlighting source
• Thinner and lighter weight
• More durable, safer and impact resistant
• Flexible
• Cost-effective

• Cons
• Require a strong barrier against moisture
• Limited lifetime particularly for the blue color

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t
Vaio with flexible OLED screen (Credit Scott
Ard/CNET)
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The Sony Reader and Walkman redone with flexible
OLED technology. (Credit Scott Ard/CNET)
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Flexible AMOLED

• enables a lighter and thinner display
• high refresh rate
• rugged and not prone to breakage
• consume significantly less power
• large area displays can be made cheaply because
  of the low temperature process used and their
  possible roll-to-roll manufacturing.
• at the proof-of-concept stage for conformable and
  rollable displays
• Samsung is the leading developer of AMOLED
  displays
• 2009 worlds first flexible AMOLED display with a
  6.5 screen announced

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LCD vs Flexible AMOLED
Winner!
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Electronic paper, e-paper

• A display technology designed to mimic the
  appearance of ordinary ink on paper
• Also known as Electrophoretic Paper Display or
  EPD
• Capable of holding text and images indefinitely
  without drawing electricity, while allowing the
  image to be changed later
• More comfortable to read than conventional
  displays due to stable image
• Considered an eco-friendly technology due to low
  power consumption
• More than a dozen companies have announced work
  on active e-paper programs 
• Colour prototypes exist, but their
  commercialistaion has yet to be started
• EPD only recently took off as "the" modern
  textual and still image display technology

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E-paper key features

• Flexible and durable
• Impact resistant
• Long lifetime It can be updated up to 1 million
  times
• Image retain without power
• Reflects light like ordinary paper
• Extremely thin
• High contrast
• Wide view angle almost 180 degree

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E-paper

• First developed in 1970s by Xerox inspired by the
  idea of a paperless office
• Fujitsu, E Ink and others introduced the EPD in
  film (active matrix display), flexible form,
  Seiko launched the first e-paper wristwatch in
  2005
• In November 2007 the EPD finally hits the market
  with Amazon launching Kindle, Sony its e-reader,
  Bookeen launched the Cybook and iRex its iLiad.
• In March 2009 Fujitsu begins consumer sales of
  worlds first color e-paper mobile terminal
  FLEPia

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Electronic paper

• Comprises two different parts
• electronic ink, "frontplane
• electronics required to generate the pattern of
  text and images on the e-ink page, the
  "backplane".

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E-paper production aspects

• The production structure of electronic paper is
  fairly complex.
• In many cases this manufacturing is contracted
  out.
• Backplane is manufactured by another group of
  firms.
• Additional group of firmsconsumer product
  firmswho design and market the product into
  which the e-paper display fits
• For example, the e-readers marketed under the
  Sony brand have incorporated e-paper
  technology from E Ink and backplane technology
  from Polymer Vision.

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E-paper frontplanes

• Electrophoretic Technology
• E Ink
• SiPix
• Bridgestone
• Cholesteric LCD Technology
• Fujitsu
• Hitachi
• Kent Display
• Kodak
• Nemoptic
• ZBD Display
• Electrowetting Technology
• Liquivista
• Electrofluidic Technology
• Gamma Dynamics

• Electrochromic Technology
• Acreo
• Aveso
• Ntera
• Siemens
• Interferometric Modulator Technology
• Qualcomm
• Photonic Crystal Technology
• Opalux
• REED Technology
• Zikon
• Bistable LCDs

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E-paper backplanes

• HP
• NEC
• Plastic Logic
• Polymer Vision
• Prime View International
• Ricoh
• Samsung
• Seiko Epson

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Gyricon

• first electronic paper
• greek for rotating image
• based on electrocapillarity movement of
  coloured liquids against a white background 
• consists of polyethylene spheres between 75 and
  106 micrometres across embedded in a transparent
  silicone sheet, with each sphere suspended in a
  bubble of oil so that they can rotate freely.
  Each coloured sphere is white on one side and
  black on the other.
• Xerox closed its Gyricon operation in December
  2005 for financial reasons, but is still
  licensing technology to other companies
• Further developed by other companies
• at the FPD 2008 exhibition, Japanese company
  Soken has demonstrated a wall with electronic
  wall-paper using this technology

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E Ink

• E Ink is a specific proprietary type of
  electronic paper
• Also know as electrophoretic frontplane
  technology
• Manufactured by E Ink Corporation, founded in
  1997 based on research started at the MIT Media
  Lab
• Currently mostly available commercially in
  grayscale
• Commonly used in mobile devices such as e-Readers
  and to a lesser extent mobile phones and watches
• Material is processed into a film for integration
  into electronic displays
• Main use for an text-based rendering

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E Ink
Microcapsules, 100 microns in diameter
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E Ink with color filters
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E Ink

• Pros
• paper-like high contrast appearance
• twice the contrast of a LCD panel
• ultra-low power consumption
• thin, light form
• unrestricted size

• Cons
• slow response time, not suitable for motion
  picture
• not possible to implement sophisticated
  interactive applications due to response time
• ghosting
• costly

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iLiad e-reader in sunlight
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• Citizen's flexible digital wall clock
• 21-inches x by 52-inches
• battery lasts 20 h more than
• traditional digital clock
• costs 4000

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Cholesteric liquid crystal displays (ChLCD)

• Developed by companies IBM, Philips, HP and
  Fujitsu, which have demonstrated actual devices
• Cholesteric liquid crystal
• same crystals as in LCDs
• a type of liquid crystal with a helical structure
• by applying a current crystals change from a
  vertical to a horizontal position.
• ChLCD technology could become the dominant
  e-paper technology of the next decade.

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Cholesteric liquid crystal displays (ChLCD)

• Pros
• flexibility and even bendability
• thinness, at approximately 0.8 millimeters
• Lightness
• a bi-stable nature, requiring no power to
  maintain an image and very little power to change
  it
• good brightness, contrast, and resolution
• vivid color and a decent refresh rate capable of
  displaying animation and possibly even video.

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Electrowetting display (EWD)

• Developed and patented by Dutch company called
  Liquavista
• Merges the advantages of LCDs and e-ink displays
• Uses a process called electrowetting, which uses
  small electrical charges to move colored oil
  within each pixel
• Electrowetting is a proven process, used for
  focus mechanisms in cameras and cellphones
• All the assets of LCD, but with 2x, 3x, 4x the
  performance
• Fundamentally brighter, more colourful displays
• Simplified LCD-like manufacturing process
• Initially targeted at e-reader markets followed
  by mobile phones

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Electrowetting display (EWD)
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EWD
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Source www.displaysearchblog.com
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EWD

• Cons
• oil response speed
• getting enough light to reflect back off the
  screen in sunshine
• mass-productions aspects

• Pros
• uses natural forces and simple materials
• frame rate 60 times per second, enough to run
  videos
• work well in sunlight and viewed picture gets
  even crisper
• 3 to 4 more efficient than LCD screens because of
  the higher level of backlight passing through
  each pixel.
• large number of grey scales

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Electrochromic Displays

• Display consists of a layer of electrochromic
  material sandwiched between two electrode layers.
  
• Material changes from one colour to another when
  stimulated by an electric current. The top
  electrode layer is made from transparent plastic
• The electrochromic mixture used by Siemens, which
  enables the screen to work so rapidly, include
  conductive polymers such as polyaniline.
• The display is controlled by a printed circuit
  and can be powered by a very thin printable
  battery or a photovoltaic cell.
• The goal is to be able to create the entire
  device the display and its power source using
  the same printing method, so that manufacturing
  costs would be as low as possible.

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mirasol displays - fullcolor e-paper

• Developed by Qualcomm MEMS Technologies, Inc.
• Uses a reflective technology, called
  interferometric modulation (IMOD). The technology
  uses microelectromechanical systems (MEMS)
  technology to imitate the way butterfly wings
  shimmer - a process called biomimetics, or
  imitating things found in nature.
• In December of 2008 the Institute of Industrial
  Science (IIS) of the University of Tokyo
  developed a MEMS display by using roll-to-roll
  printing technology
• Expected to be seen on cell phones, e-book
  readers and tablets by the end of 2010

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Mirasol low-power MEMS display for e-readers, in
a proof-of-concept built by Qualcomm. Image
Qualcomm MEMS Technologies, Inc.
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mirasol displays
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mirasol displays

• Pros
• color
• very low power consumption, no backlight
• easy to view in the sunlight
• no delay in screen refreshing due to faster
  refresh rate

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Amazon Kindle

• 6" E Ink electronic paper display
• 600 x 800 pixel resolution at 167 ppi
• 16-level gray scale
• Price 259

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Fujitsu Flepia

• 8 Color e-paper
• 768 dots x 1,014 dots (XGA)
• Color
• 260,000 colors (3 Scans)
• 4,096 (2 Scans)
• 64 colors (1 Scan)
• Redraw speed
• 1.8 seconds (1 Scan)
• 5 seconds (2 Scans)
• 8 seconds (3 Scans)
• Price 849

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Application areas

• Newspapers
• E-books
• Digital signage
• Medical
• Toys and games
• Clothing
• TVs

• Interior design
• Smart cards
• Automotive consoles
• Mobile
• Military equipment

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Future
The Morph concept from Nokia Image Nokia
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• Holy grail of e-paper
• Will be embodied as a cylindrical tube, about 1
  centimeter in diameter and 15 to 20 centimeters
  long, that a person can comfortably carry in his
  or her pocket. It will cost less than 100.

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Conclusion

• E-paper display technology has now become an
  integral part of ebook reading devices.
• 2010 year of e-paper based devices. CES 2010 had
  a lot of new e-paper devices being announced.
• Color e-paper to come in few years, first
  products possibly in 2011 -2012
• The technology of printed electronics will
  deliver low-cost production
• Give away e-paper display products by 2015.
• Content availability

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Questions?
Questions?
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Thank you!