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

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

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

3. 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.

4. 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

5. 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

6. 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

7. Flexible displays roadmap Source: Displaybank, 'Flexible Display Technology and Market (2007~2017)' report

8. 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

9. Flexible displays market - demand forecasts Source: Displaybank, 'Flexible Display Technology and Market (2007~2017)' report

10. 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

12. Main flexible display technologies Flexible LCDs FOLED, Flexible AMOLED E-paper: Electrophoretic, CholestericLCDs, Electrowetting Displays (EWD), ElectrochromicDisplays InterferometricModulatorTechnology

13. 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

14. Flexible LCDs

16. 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

17. FOLED Source: Universal Display Corporation

18. 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.

19. 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

20. t Vaio with flexible OLED screen (Credit: Scott Ard/CNET)

21. The Sony Reader and Walkman redone with flexible OLED technology. (Credit: Scott Ard/CNET)

22. 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 rollabledisplays • Samsung is the leading developer of AMOLED displays • 2009 world’s first flexible AMOLED display with a 6.5” screen announced

23. LCD vs Flexible AMOLED Winner!

24. 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

25. 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

26. 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 world’s first color e-paper mobile terminal FLEPia

27. Electronic paper • Comprisestwodifferentparts: • electronicink, "frontplane” • electronicsrequired to generate the pattern of text and images on the e-inkpage, the "backplane".

28. 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 firms—consumer product firms—who 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.

29. 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

30. E-paper: backplanes • HP • NEC • Plastic Logic • Polymer Vision • Prime View International • Ricoh • Samsung • Seiko Epson

31. 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

34. 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

36. E Ink Microcapsules, ~ 100 microns in diameter

37. E Ink with color filters

38. Cons slow response time, not suitable for motion picture not possible to implement sophisticated interactive applications due to response time ghosting costly E Ink Pros • paper-like high contrast appearance • twice the contrast of a LCD panel • ultra-low power consumption • thin, light form • unrestricted size

41. iLiad e-reader in sunlight

43. Citizen's flexible digital wall clock • 21-inches x by 52-inches • battery lasts 20 h more than traditional digital clock • costs $4000+

44. 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.

45. 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.

47. 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

48. Electrowetting display (EWD)

49. EWD

50. Source: www.displaysearchblog.com