Post on 07-Aug-2015
VISVESVARAYA TECHNOLOGICAL UNIVERSITY BELGAUM
Seminar Report on
OLED FLEXIBLE ELECTRONIC PAPER DISPLAY
Submitted by
PRAVEEN KUMAR SHERI 4JE10EC424
In partial fulfillment of the requirement for the award of the
Bachelor Degree
in
Electronics and Communication Engineering
Under the Guidance of
Prof. A Thyagaraja Murthy
Associate Professor
Department of Electronics & Communication
DEPARTMENT OF ELECTRONICS& COMMUNICATION ENGINEERING SRI JAYACHAMARAJENDRA COLLEGE OF ENGINEERING
Mysore-57001
2014-15
CERTIFICATE
_________________________________________________________________
CERTIFICATE
This is to certify that the Seminar entitled “OLED Flexible Electronic Paper
Display” is bonafied work carried out by PRAVEEN SHERI (4JE10EC424) in partial
fulfillment of VIII Semester to award the Bachelor Degree in Electronics and
Communication Engineering of the Visvesvaraya Technological University,
Belgaum during the year 2014-15. It is certified that all corrections/suggestions
indicated for Internal Assessment have been incorporated in the Report and
deposited in the department library. The Seminar Report has been approved as it
satisfies all the academic requirements in respect of Seminar prescribed for the
Bachelor of Engineering Degree.
Prof. A Thyagaraja Murthy
Guide &Co-Ordinator
Associate Professor
Department of Electronics & Communication
SRI JAYACHAMARAJENDRA COLLEGE OF ENGINEERING
MYSORE-57001
DEPARTMENT OF ELECTRONICS & COMMUNICATION
ENGINEERING
CONTENTS
Certificate ii
Acknowledgement iii
1. INTRODUCTION
1.1 History Of Flexible Display
1
1.2 Flexible Display
1
1.3 Features 3
2. WORKING PRINCIPLE OF E-PAPER 5
3. KEY SUCCESS FACTORS
7
4. APPLICATIONS AND FUTUREOF E-PAPER 10
4.1 Applications 10
4.2 Future Of E-Paper
11
5. BEND GESTURES 11
5.1 Recognizing Bend Gestures 12
5.2 Defining Bend Gestures
13
5.3 Applications And Action Pair Design
14
5.4 Procedure 14
5.4.1 Defining Bend Gestures 15
5.4.2 Assigning Bend Gestures to Actions
16
5.4.3 Using Bend Gestures Across Applications
17
6. FLEXIBLE OLEDS
19
6.1 Different Kinds Of Flexibility
20
6.2 Flexible Oled Products
20
6.3 Curved Oled Tvs
21
7. LIMITATIONS
23
8. CONCLUSION 24
References 25
ACKNOWLEDGEMENT
Inspiration and guidance are valuable in all aspects of life, especially what is academic.
“Experience is the best teacher”, is an old age. The satisfaction and pleasure that accompany the
gain of experience would be incomplete without mentioning the people who made it possible.
I am extremely thankful and grateful to our guide Prof. A Thyagaraja Murthy Associate
Professor, Dept. of Electronics and Communication Engineering, SJCE. He is being our
guide has taken keen interest in the progress of the seminar work by providing facilities and
guidance. I am indebted to my guide and co-ordinator for his inspiration, support and kindness
showered on us throughout the course.
I express my profound sense of gratitude to Dr. N. R. Shanmukha Swamy, HOD, Dept.
of Electronics and Communication Engineering, SJCE for giving me the opportunity to
pursue my interest in this Seminar.
I express my heartfelt gratitude to Dr. Shakigur. Rehman Principal for providing me
the resources and support for making this seminar possible.
Lastly, heartfelt thanks to my parents, friends and teaching and non-teaching staff of my
college for their encouragement and support.
PRAVEEN SHERI
OLED FLEXIBLE ELECTRONIC PAPER DISPLAY
CHAPTER 1
INTRODUCTION
1.1 Histroy Of Flexible Display
The era of mobile devices began in the second half of the 1990s. As cell phones became
widely used, the market for mobile equipment grew at a rapid rate. The main area of
competition was in making devices smaller and improving call quality. Once the ideal size
and call quality was achieved it became harder to differentiate the products in the early
2000s.As a result, companies started competing to develop simple wireless telecom devices
and added value for customers by offering colour display, MP3 and camera functions. The
landscape of the market changed quickly as GSM and CDMA combined to form WCDMA or
3G.The market became more operator-driven as telecom companies used a variety of
marketing methods, including providing customers with subsidies and two-year contracts. By
the second half of 2005, most phones had similar design and functions (camera, colour
display, 3G) and with differentiation becoming more difficult, commoditisation started and
competitors focused on lowering production costs.
Table1.1 The History Of Handset Industry After 2005, competitors turned their attention to making cell phones essential in everyday life.
As a result, products with differentiated form factors, such as casing, keypad and slim form DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING, SJCE,MYSORE Page 1
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factor, were designed. The market for high-end phones started to take off. Consumer interest in
design was an opportunity for Samsung and LG to strengthen their positions in a market
dominated by cost efficient companies, such as Nokia.Then Apple’s iPhone arrived, providing
completely new experiences, such as entertainment features and a highly distinctive design and
customization options. The handset market went through rapid change as Wi-Fi internet
revolutionised the data side of the business. Apple was the dominant force until the advent of
Android-based phones. Differentiation has become even harder with most companies using full
HD panels, a standardized quad-core application process, touch screen and the Android operating
system. In a commoditised market, design is the high-end market’s main differentiating point.
They believe flexible display will take this to a new level as the new technology will see hand-
held digital devices become lighter ,thinner and more convenient for users. Display technology is
advancing in four directions: 1) improving the sense of reality through 3D TV, 2) adopting
additional functions, such as touch and internet connectivity, 3) enabling greater mobility via
lighter and thinner products, such as in smartphones and tablet PCs, and 4) expanding
adaptability for displays in homes and industries via thinner, larger products, such as UHD TV.
Until recently, progress on flexible display technology has been slow. The main reason is that
companies have already made heavy investments in LCD, the technology used in flat display
panels.
Fig1.1 Display Development DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING, SJCE,MYSORE Page 2
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1.2 Flexible Display Flexible display requires a completely different set of technologies, the first of which is OLED
display, which has a faster response time and outstanding colour definition .OLED is the base
technology for flexible display because of its self-illuminating properties that allows greater
design flexibility. Samsung Display has made rapid progress in OLED technology and is already
using it its smartphones. LG Display recently commercialized large TV displays using this
technology. Flexible display uses plates that are pliable and as thin as paper. They can be bent
without being damaged, making it possible to create products that are thin, durable and flexible.
The potential of this technology is substantial as the ultimate goal will be cheap digital devices
that can be rolled up like paper. While research in the domain of flexible display interfaces has
been ongoing for the better part a decade, there is, to our knowledge, little to no user interface
research where actual flexible displays were deployed. Most of the display technologies used in
prior studies were either based on simulations using projection on paper ,rigid LCD displays on a
flexible substrate or paper mockups .These methods of simulating real flexible displays
potentially introduce biases for the evaluation of interactions. By using real flexible displays and
integrated bend sensing they achieve interactions that align with the performance characteristics
of devices that could be commercially available in the immediate future. While there may be
suggestions that bending of a flexible display can be as effective and efficient an input technique
as button controls in rigid displays for tasks like paging, the case for the use of flexible over rigid
screens is not necessarily based on the superior efficiency of interactions. Indeed, much work is
required for flexible touch screens to become as effective as rigid ones. However, while rigid
screens may continue to have the edge in terms of interaction efficiency for some time, they
believe there are sufficient practical and interactional reasons for flexible displays to achieve
mass adoption. The likely reason for adoption of flexible displays is that they may closely
approximate the look and feel of paper document . 1.3 Features Rigid Graphical User Interfaces (GUIs) often feature input that is indirect, one-handed, and
dependent on visual cues. By contrast, paper documents, and presumably flexible displays, may:
1. Be very thin, low-weight, yet rugged, allowing superior portability over any current mobile
computing form factor. 2. Have many form factors. This allows for distinct physical affordances
that relate to specific functionalities: reading a newspaper serves a different purpose than reading
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a product label, and implies a different form factor. 3. Provide variable screen real estate that fits
the current context of use. 4. Have many physical pages, each page pertaining only to a specific
and physically delineated task context. 5. Use physical bend gestures with strong tactile and
kinesthetic feedback for efficient navigation. Prior simulations of flexible displays have already produced a library of paper-like interaction
styles, most of which focus on the use of bend gestures. A bend gesture is the physical, manual
deformation of a display to form a curvature for the purpose of triggering a software action. In
this paper, we present an evaluation of user preferences for bend gestures in executing a real set
of tasks, using an actual flexible display. We designed a study in which users were asked to
design their own bend gesture using a thin film E Ink display with integrated bend sensors. This
approach has two distinct advantages over prior work:(1) visual feedback is provided directly on
the display itself, and (2) dynamic material characteristics of bending layers of sandwiched
flexible electronics were included. In the first part of our study, we asked participants to define8
bend gesture pairs. In the second part, we asked them to evaluate the appropriateness of their
bend gestures for us with multiple actions. Finally, users were asked to use and evaluate bend
gestures in the context of complete tasks(e.g., operating a music player). Results showed that
users selected individual bend gestures and bend gesture pairs that were conceptually simpler
and less physically demanding. There was a strong agreement among participants touse 3 bend
gesture pairs in applications: (1) side of display,up/down (2) top corner, up/down (3) bottom
corner, up/down. There was also strong consensus on the polarity(physical bend direction: up or
down) of bend gesture pairs for actions with clear directionality (e.g., navigating left and right to
select an icon). In the early stages, flexible display will be used in small displays, such as
watches, which can be mass produced. Then, depending on how the technology matures, it will
be applied in smartphones and tablets.
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CHAPTER 2
WORKING PRINCIPLE OF E-PAPER
E-paper comprises two different parts: the first is electronic ink, sometimes referred to as the ―frontplane‖; and the second is the electronics required to generate the pattern of text and
images on the e-ink page, called the ―backplane‖.
Over the years, a number of methods for creating e-ink have been developed. The Gyricon e-ink
developed in the 70s by Nick Sheridon at Xerox is based on a thin sheet of flexible plastic
containing a layer of tiny plastic beads, each encapsulated in a little pocket of oil and thus able to
freely rotate within the plastic sheet. Each hemisphere of a bead has a different color and a
different electrical charge. When an electric field is applied by the backplane, the beads rotate,
creating a two-colored pattern. This method of creating e-ink was dubbed bichromal frontplane.
Originally, bichromal frontplane had a number of limitations, including relatively low brightness
and resolution and a lack of color. Although these issues are still being tackled, other forms of e-
ink, with improved properties compared to the original Gyricon, have been developed over the
years.
One such technology is electrophoretic frontplane, developed by the E Ink Corporation.
Electrophoretic frontplane consists of millions of tiny microcapsules, each approximately 100
microns in diameter—about as wide as a human hair. Each microcapsule is filled with a clear
fluid containing positively charged white particles and negatively charged black particles. When
a negative electric field is applied, the white particles move to the top of the microcapsule,
causing the area to appear to the viewer as a white dot, while the black particles move to the
bottom of the capsule and are thus hidden from view. When a positive electric field is applied,
the black particles migrate to the top and the white particles move to the bottom, generating
black text or a picture.
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The brightness and resolution of electrophoretic-based e-ink is better than that of bichromal-
based e-ink, but both are monochromatic in nature. To create color, E Ink joined hands with the
Japanese company Toppan Printing, which produces color filters.
Another drawback of electrophoretic e-ink is its low refresh rate, making electrophoretic e-ink
unsuitable for displaying animation or video. Since it takes time for the particles to move from
one side of the microcapsule to the other, drawing a new text or image is too slow and creates a
flicker effect.
A completely different solution for creating e-paper, known as cholesteric liquid crystal
(ChLCD), is being developed by such companies as IBM and Philips, as well as HP and Fujitsu,
which have demonstrated actual devices. ChLCD technology is based on the well-known and
widespread technology of liquid crystal displays (LCDs), which work by applying a current to
spiral-shaped liquid-crystal molecules that can change from a vertical to a horizontal position.
Although other potential technologies for developing advanced color electronic paper exist such
as photonic crystals (P-ink) recently covered by TFOT, many analysts believe that ChLCD
technology could become the dominant e-paper technology of the next decade. This assessment
relates to the high level of maturity exemplified by the current LCD industry, as well as to the
fact that ChLCD technology currently offers what many analysts see as the ideal list of features
for e-paper: flexibility and even bend ability; 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; as well as vivid color and a decent refresh
rate capable of displaying animation and possibly even video.
Fig2.1 A Colour Illustration Of The Way Chlcd Technology Works
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CHAPTER 3
KEY SUCCESS FACTORS
The commercialisation of flexible display will depend on technology, mass production and cost.
We identify four key challenges.
1: Re-Using LCD Fabs. LCD panel businesses already make a wide range IT products and TVs. Making sizeable new
investments could be a burden as profitability has been declining due to oversupply. It will make
more sense for these companies to convert existing LCD business lines to OLED to produce
flexible display. Samsung Display and LG Display have already made substantial investments in
OLED, giving them a head start on their Japanese and Taiwanese competitors in the flexible
display market. We expect the LTPS-based RGB OLED technology – already being used by
Samsung Display in its high definition OLED small-size panel production – to become the
industry standard for flexible display.
2: A Substitute For Glass. Glass is currently used in the upper and lower layers of LCD and OLED panels. The reason is
simple – it is flat, transparent and resistant to heat and moisture. However, glass has low levels of
elasticity, making is unsuitable for flexible display.Next-generation plastic looks like the best
substitute. Currently, it can be used in high performance thin transistors as its thermal expansion
coefficient is low. However, this is expensive and not efficient due to its opaqueness. However,
on the plus side a wide range of materials can be applied in plastic. Research is being done on
materials with high thermal resistance, such as PET (Polyethylene Terephthalate), PC
(Polycarbonate), PES (Polyether Sulfone), PI (Polyimide) and how plastic boards can withstand
the process of thinning (see table on the next page). We believe polyimide plastic film is most
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compatible with flexible display since polyimide provides the highest thermal resistance.
Polyimide is a transparent polymer material that has a relatively low degree of crystallisation and
an amorphous structure. Moreover, it is an excellent mechanical material and provides
outstanding heat and chemical resistance, electric characteristics and stable size based on a rigid
chain structure. It is widely used in auto, aviation, aerospace and flexible circuit boards. Despite its advantages in being applicable in insulating material, flexible film, and aerospace
aviation, polyimide is partially used in FPCB (flexible printed circuit board) and costly displays
within aeroplanes due to its unique yellow colour; efforts are being made to lower this yellow
colour and raise transparency. The result of this work,polymer, is likely to be in use in 2014.
3: Plastic To Replace Frontal Glass
Table3.1 Condition of plastic substrate vs. physical character of glass
Frontal glass needs to be more scratch proof than the lower glass panel. A plastic substitute
would need to have the same hardness as glass, but this technology is still at an early stage. Some
Japanese companies are making progress in this area, but the cost is much higher than tempered
glass, making commercialisation difficult.
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4: Vertical Integration Some Japanese companies have already developed technologies for the commercialization of
flexible display and have even introduced some prototypes. However, they are being produced
by a single company, so there is a lack ofcompetition in cost and mass productivity.While a
number of technological issues still need to be resolved by individual material and panel
companies, we believe that vertical integration among material developers, components and
panel producers, and handset makers is essential for the commercial success of flexible display. Given the newness and complexity of the technology, co-operation among the companies
in the supply chain, especially in the early stages of mass production, will be important. We think flexibility on pricing is also essential.
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CHAPTER 4
APPLICATIONS AND FUTUREOF E-PAPER
4.1 Applications
1.Clearly, great progress has been made in the field of e-paper since the invention of Gyricon.
Companies such as E Ink, SiPix, and Polymervision, as well as such giants as Sony, IBM,
Hewlett-Packard, Philips, Fujitsu, Hitachi, Siemens, Epson, and many others, are continuing to
develop e-paper technology. Founded in 1997 and based on research begun at the Massachusetts Institute of Technology’s Media Lab, E Ink developed proprietary e-paper technology that
already has been commercialized by a number of companies, including iRex Technologies and
Sony, both of which already have commercial e-paper readers on the market.
At this stage, some of the products based on E Ink’s technology are little more than
expensive gimmicks, such as Seiko’s limited-edition e-paper watch (priced at over $2,000).Other
products to be marketed have more substantial applications. E-paper thin color displays for
packaging, currently under advanced development at Siemens, could display prices on products
dynamically, instantly altering a product’s price when necessary (using such low-power wireless
technology as radio-frequency identification, or RFID, for example). A dynamic expiration date,
which would graphically display the amount of time remaining for food and drug consumption,
is another potential application.
Fig.4.1 Colour Ebook-Reader (Left) And Irex Iliad (Right)
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2.Potential applications of e-paper technology is staggering. In addition to a new method for
labeling foods and drugs, it could be used to label anything from shelves to office binders. One
of the original uses of the Gyricon e-ink was in advertising and billboards; the bi-stable nature of
the technology made the Gyricon a useful and cost-effective billboard technology. E-paper
displays can also be used as low-power digital screens for a variety of electronic appliances,
from microwaves to MP3 players.
Fig4.2 Citizen E-Ink Clock
3.Although many potential applications for e-paper technology exist, one of the more exciting
products is the e-paper reader, which may soon replace the age-old newspaper and possibly even
certain types of books; some technical literature may be perfectly suited for e-paper. The next
generation of e-paper readers will add color, include improved hardware that can refresh pages more
quickly, and have more advanced wireless capabilities.Existing readers from Sony, iRex, and a
number of other companies are still quite expensive and suffer from some of the problems that plague
early technology models. The next generation of readers will also be flexible, making such
applications as digital maps an attractive option, especially when connected to GPS hardware and
software. Although e-paper readers like iRex’s iLiad, are already equipped with wireless Internet
communication, they are not well suited as general-purpose Web-surfing devices. Electronic readers
of the future will one day become the ultimate handheld devices.Having mentioned in this article a
number of potential applications for e-paper, it is possible that the most important applications of this
technology have not yet been invented.
4.2 Future Of E-Paper
The initial Gyricon technology proved expensive and had poor resolution; it was really only
usable in the sort of message-board-display systems that were produced by Gyricon Media. The
development of true e-paper really only dates from about 1998, when E Ink first demonstrated
their electrophoretic frontplane display technology; this gave a higher resolution and was
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OLED FLEXIBLE ELECTRONIC PAPER DISPLAY potentially much cheaper. Since then, other companies, such as SiPix, have come out with electrophoretic display
technologies. In the last four years, we have also seen companies like HP and Fujitsu bring out
flexible displays that use cholesteric LCD technology. (Cholesteric refers to the phase of a liquid
crystal in which the molecules are aligned in a specific manner. In Fujitsu’s case, for example, up
to 50 percent of incident light in specific wavelengths and colors is reflected). E-paper has to be a
cheap, reflective, low power, and preferably bendable, or have rollable display technology, and
we are only just seeing the development of the technologies that can deliver this, namely an
electrophoretic frontplane bonded to a flexible organic electronic backplane. These are the
displays currently on the verge of being launched by Plastic Logic and Polymer Vision.
Fig4.3 Plastic Logic E-Paper
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CHAPTER 5
BEND GESTURES
5.1 Recognizing Bend Gestures
PaperPhone has a training mode during which the user designs and records bend gestures, and an
operating mode in which the system uses currently defined bend gestures to trigger software actions.
In the training mode the bend sensor data is recorded and used to train a k-Nearest-Neighbor(kNN)
algorithm with k=1. kNN assigns the label of the most similar examples (the closest neighbor) to the
example to classify. In our case, the examples are vectors from the live values of the 5 bend sensors.
We trained the system to recognize the flat shape as the baseline, or a neutral state. In the operating
mode, in which trained bend gestures trigger software actions, a bend gesture is recognized when the
display is bent to a curvature that is closer to a recorded shape than a flat shape. This recognition
algorithm requires only a single training input for each gesture, making it ideal for rapid
programming of user defined bend gestures.To minimize the unintended triggering of actions by false
positives, an additional stage of filtering was implemented immediately after the raw kNN
classification output. The software takes a sample of the recognized bend gesture alternatives,
reporting the mode value from this set as the recognized bend gesture. The window size of the
sample ranged from 5 to 40 samples depending on the number of candidate bend gestures and on the
similarity of these bend gestures to one another. This window size was manually defined based on
observations of system performance. The final stage of the Max program maps the recognized bend
gestures to a set of actions on the flexible display. For this purpose, we designed a state machine in
Max that takes recognized bend gestures as inputs and produces states as output. The state data
includes the specific action to be executed (such as placing a phone call), and the next state the state
machine should be in on the next cycle (such as a menu for icon navigation). This information is
transmitted to the Gumstix computer, which renders the appropriate images on the flexible display of
PaperPhone. The state machine allows bend gesture pairs to be used in isolation and applied to all the
individual actions, or used in concert to perform compound tasks. Although PaperPhone is fully
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flexible, the current design contains a number of fragile connectors on the left side of the display that
may be damaged while bending. We protected these connectors by affixing a less pliable plastic
board to this side. The right side of the PaperPhone display allows bends up to 45 degrees.Our bend
gesture recognition system requires a minimum bend of 10 degrees for proper detection of bend
gestures. 5.2 Defining Bend Gestures We defined a bend gesture as the physical, manual deformation of a display surface to form a
curvature for the purpose of triggering an action on a computer display. To aid in the design of our
study, we developed a simple classification scheme for bend gestures based on the physical
affordances of the display, the sensing data available from the bend sensor array, and the PaperPhone
bend gesture recognition engine. We classify the bend gestures our users could perform according to
two main characteristics: the location of the force exerted on the display, and the polarity of that
force. The rigid bezel allowed three fundamental locations of the force that can be exerted on the
display: Bend gestures could be located on either right corners, or along the side of the display.
Individual bend gestures could be of two sorts: a single bend or a compound bend. A single bend
gesture contains only one fold, and is generated by applying a force to a single location. A compound
bend consists of more than one fold, and is generated by applying forces to multiple location
simultaneously, e.g., bending both corners of the display. For each bend location, the polarity of a
bend gesture could be either up (towards the user) or down (away from the user). Note that we
recognize alternative criteria, such as the amount of force exerted on the display,the number of
repetitions of bends, the velocity of movements,continuous vs. discrete use of bends and the
orientation of the screen (portrait or landscape). However, given the constraints of our hardware, and
in order to limit the overall time spent by participants designing bend gestures,we decided against
investigating these in the present study.
5.3 Applications And Action Pair Design They selected five typical applications that are commonly performed on a mobile phone: navigating
through icons, selecting contacts and making phone calls, playing music, reading a book, and
navigating a map (see Table 5.1). Figure5.1 shows four of the screen layouts on our PaperPhone
prototype. Many user actions have a symmetrical correlate.They call such symmetrical actions action
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pairs.
Table5.1 Mobile Applications And Associated 10 Action Pairs, To Which Bend Gesture Pairs
Were Mapped By Participants.
We identified 20 actions (10 action pairs) for the five applications.
Figure 5.1 Screenshots Of 4 Of The Applications: Icon Navigation,Contacts, Music Player And
Bookreader.
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OLED FLEXIBLE ELECTRONIC PAPER DISPLAY (a) Icon Navigation The user was required to navigate a series of twelve application icons distributed in a 3x4 grid pattern
(see Figure6.1a). They were asked to perform these actions by going left, right, up and down.
Opening an application led to a splash screen. The user could close the application which returned the
interface to the set of application icons. (b) Contacts The user was asked to navigate up and down a list of contacts (see Figure 6.1b). Once the user had
chosen a contact, she could select it to view the contact details. The user could close the contact
details and return to the main list, or call the contact. When calling, the user could drop the call. (c) Music Player The user was asked to play and pause a song, and select the previous or next song (see Figure 6.1c).
To minimize bias, we provided no visual or verbal cues of the directionality of these actions. When
the play or pause action was performed, the state of the action was displayed on the screen. (d) Book Reader The user was asked to navigate to the previous or next page (see Figure 6.1d). We again avoided
introducing directional bias by not asking users to page up, down, left or right. We limited actions for
this application to a single action pair to allow us to observe the user’s orthogonality considerations
in applying this mapping. (e) Map Navigation The user was asked to zoom in or zoom out . Because of the limited refresh rate of the display,
zooming was implemented as a discrete action. We again limited this application to a single action
pair.
5.4 Procedure Before starting the experiment, users were provided with minimal instructions to prevent damage to
PaperPhone. We physically demonstrated a single bend gesture (Figure 6.2), emphasizing the degree
to which the display could be bent without damaging the device. We instructed the users to avoid
bending directly on the left edge of the device, where the electrical contacts were located. We guided
the participants to hold the display as if it were wireless, and to ignore and not hold the connecting
ribbon cables. Participants were informed that the system would only recognize discrete bend
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Figure 5.2 The Eight Participant Defined Individual Bend Gestures Used In Bend Gesture Pairs.
gestures. Aside from this, we did not instruct participants on bend gestures. Throughout the
experiment, participants were encouraged to think aloud, so as to verbalize their thought processes.
5.4.1 Defining Bend Gestures To encourage users to consider a wide variety of bend gestures, their first assignment was to design 8
unique pairs of bend gestures. We derived 8 as the number of bend gesture pairs empirically from a
pilot study: a high enough number to challenge beyond obvious choices, while allowing completion
within 2 hours. Participants were allowed to reuse individual bend gestures in different pairs, as long
as the resulting pairs were not identical. First, the user executed each bend pair once to train PaperPhone’s bend recognition system. After the system was trained, it executed an action whenever
the bend gesture was performed. To emphasize that each bend gesture was going to be associated
with an individual action, and to encourage participants to create comfortable bend gestures, we gave
the users the opportunity to try out their bend gesture with an abstract action. Here, the display turned
either to black or white when the user performed a bend gesture pair successfully. This continued
until they had defined all 8 pairs.
5.4.2 Assigning Bend Gestures to Actions The second part of the experiment let users test out each bend gesture pair with each individual action
pair. We selected 7 unique action pairs from the list of 10 (Table 6.3.1). The up/down action pair
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from the Contacts application was not repeated, as it is a duplicate of the up/down action pair in the
Icon Navigation application. To examine orthogonality, we reserved the Book Reader and Map
Navigation applications for evaluation . In the Icon Navigation application, users moved left, right,
up, down through icons, opened and closed the application. In the Contacts application, users opened
and closed a contact, called the contact and dropped the call. In the Music Player, users played or
paused, and selected the next or previous song.Users first assigned the mapping of each bend gesture
to an action, meaning that they selected which bend gesture components of the previously designed
bend gesture pair would trigger the individual actions in the action pair. The user was then able to try
out each bend gesture pair/action pair mapping, after which they rated the appropriateness of the
bend gesture pair for this action pair using a 5-point Likert scale of agreement (1 Strongly Disagree-5
Strongly Agree).This was repeated for all 8 bend gesture pairs. The participants were then asked to
determine their favorite bend gesture pair for the action pair. When a user suggested an alternative
bend gesture pair, we would record this pair andadd it to our total count of bend gesture pairs. Users
each tested 56 mappings of bend gesture pair to action pairs (8bend gesture pairs x 7 actions pairs).
The presentation of bend gesture pairs for each action pair, as well as of action pairs, was
counterbalanced using a Latin-square design.
5.4.3 Using Bend Gestures Across Applications For the final part of the study, the users were instructed to try out the full suite of top ranked bend
gesture pair/action pair mappings, in each of the five applications. In the previous part, each action
pair was performed individually. In this session all of the action pairs for the active app were
available at once, allowing users to perform them in any order, independently of the pairs. Users were
free to assign any bend gesture pair to any action pair, with any polarity, whether previously used or
not. Users were reminded of their favorite bend gesture/action mappings for each application and
were instructed to determine whether there were any conflicts between these bend gestures. In the
case of orthogonality conflicts, the user was invited to revise their choice of bend gestures to
eliminate any conflicts. For each app, the system was trained with the selected bend gestures and the
user was allowed to freely test and evaluate the interaction experience. Before ending the experiment,
users were asked to identify situations where they would prefer to use bend gestures over other input
techniques.
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CHAPTER 6
FLEXIBLE OLEDS
OLED is an emerging display technology that enables beautiful and efficient displays and lighting
panels. Thin OLEDs are already being used in many mobile devices and TVs, and the next
generation of these panels will be flexible and bendable.
Fig6.1 OLED Flexible Display
6.1 Different Kinds Of Flexibility
When we talk about flexible OLEDs, it's important to understand what that means exactly. A flexible
OLED is based on a flexible substrate which can be either plastic, metal or flexible glass. The plastic
and metal panels will be light, thin and very durable - in fact they will be virtually shatter-proof.
Fig6.2 Flexible Display
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It is estimated that the first range of devices to use a flexible display won't be flexible at all. While
the manufacturer may bend the display or curve it around a non-flat surface, the final user will not be
able to actually bend the device. Still it will have several advantages: these displays will be lighter,
thinner and much more durable compared to glass based displays.
Second generation flexible OLED devices may indeed be flexible to the final user. Finally, when the
technology is ready, we may see OLED panels that you can fold, bend or stretch. This may create all
sorts of exciting designs that will enable large displays to be placed in a mobile device and only be
opened when required.
6.2 Flexible Oled Products
After years of research, in October 2013, Samsung announced the world's first product to use a
flexible OLED display - the Galaxy Round curved smartphone. This is an Android 4.3 smartphone
similar to the Galaxy Note 3, with the major feature being the 5.7" Full-HD curved (400 mm
curvature radius) flexible display (samsung simply refers to it as a flexible Super AMOLED,
strangely they are not using the YOUM brand).
Fig6.3 Different Products Of Flexible Display
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Initial capacity in both companies is low (a few hundreds of thousands of panels per month).
Samsung's capacity is higher (they are using a Gen-5.5 line and LG is using a Gen-4.5 line) but this
too will not be enough even for a single mass market phone. The company are probably waiting to
see how consumers react to those new panels before they commit to increase capacity.
Fig.6.4 Flexible Display Product
Samsung launched their YOUM flexible OLED panels in January 2013, showing some cool
prototypes of curved and flexible OLED displays.Some reports suggest that Apple is planning to use
a small (about 1.5" in size) flexible OLED panel in their upcoming smartwatch device.
Fig.6.5 YOUM Flexible Display
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6.3 Curved Oled Tvs
Both Samsung and LG are now offering curved OLED TVs. These 55" panels are slightly curved
and this offers a better viewing experience for someone who sits right in front of the TV as all the
pixels are at the same distance from his eyes. Most people however, actually prefer a flat panel. In
any case, as far as the OLED panel is concerned this isn't really a flexible OLED, it is a curved glass-
based OLED panel.
Fig.6.6 Curved OLED Tv
OLED TV production capacity is extremely low and prices are very high.
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CHAPTER 7
LIMITATIONS
The main limitation of this work resides in the physical engineering of the prototype display, which
restricted bending to one side of the display. This reduced the number of bend gestures available for
consideration. We believe this limitation did not outweigh benefits of being able to evaluate a
functional flexible display, with results representing a significant subset of findings for a full flex
display. While it was possible for us to detect continuous (analog) bend gestures, the slow refresh
rate of flexible E Ink delayed visual feedback, making real-time animation impossible. Effects of
display size on the use of bend gestures may be answered through future studies: They believe that
with appropriate material qualities, bends could apply from small to large form factors. They are
expecting touch input to complement bends and recognize the challenges this presents: current flex
touch input options are limited. In addition, there study proposed a maximum of six actions per
application, which was the max number of single bend gestures available given our constraints. An
important step to validate there bend gesture set would be to test compound applications with four
action pairs or more. Finally, it would be interesting to perform a follow-up study that compares user
generated bend gestures mappings with those produced by designers.
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CHAPTER 8
CONCLUSION
This paper propsed that, they presented PaperPhone, a smartphone with a functional flexible
electrophoretic display and 5 integrated bend sensors. We studied the use of user-defined bend
gestures for triggering actions with this flexible smartphone. Results suggest a strong preference for 6
out of 24 bend gesture pairs. In general, users selected individual bend gestures and bend gesture
pairs that were conceptually simple and less physically demanding. There was a strong agreement
among participants to use 3 particular bend gesture pairs in applications, bending the: (1) side of
display, up/down (2) top corner, up/down (3) bottom corner, up/down. For actions with a strong
directional cue, there was strong consensus on the polarity of the bend gestures. Results imply that
gestures with directional cues are preferred. Results suggest bend gestures form a useful addition to
interaction modalities of future flexible computers.
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REFERENCES
[1] Lahey, Byron, et al. "PaperPhone: understanding the use of bend gestures in mobile devices
with flexible electronic paper displays", Proceedings of the SIGCHI Conference on Human
Factors in Computing Systems. ACM, pp 1303-1312, 2011
[2] Warren, Kristen, et al. "Bending the rules: bend gesture classification for flexible displays." Proceedings of the SIGCHI Conference on Human Factors in Computing Systems. ACM, PP (607-610), 2013
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