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A flexible display or rollable display is an electronic visual display which is flexible in nature, as opposed to the traditional flat screen displays used in most electronic devices. [1] In recent years there has been a growing interest from numerous consumer electronics manufacturers to apply this display technology in e-readers, mobile phones and other consumer electronics. Such screens can be rolled up like a scroll without the image or text being distorted. [2] Technologies involved in building a rollable display include electronic ink, Gyricon, Organic LCD, and OLED.
Electronic paper displays which can be rolled up have been developed by E Ink. At CES 2006, Philips showed a rollable display prototype, with a screen capable of retaining an image for several months without electricity. In 2007, Philips launched a 5-inch, 320 x 240-pixel rollable display based on E Ink’s electrophoretic technology.[ citation needed ] Some flexible organic light-emitting diode displays have been demonstrated. The first commercially sold flexible display was an electronic paper wristwatch. A rollable display is an important part of the development of the roll-away computer.
With the flat panel display having already been widely used more than 40 years, there have been many desired changes in the display technology, focusing on developing a lighter, thinner product that was easier to carry and store. Through the development of rollable displays in recent years, scientists and engineers agree that flexible flat panel display technology has huge market potential in the future. [3]
Rollable displays can be used in many places:
Flexible electronic paper (e-paper) based displays were the first flexible displays conceptualized and prototyped. While the idea for this type of display is not recent and had been attempted by several companies in the past, only recently has mass production of this technology begun for implementation in consumer electronic devices.
The concept of developing a flexible display was first put forth by Xerox PARC (Palo Alto Research Company). In 1974, Nicholas K. Sheridon, a PARC employee, made a major breakthrough in flexible display technology and produced the first flexible e-paper display. Dubbed Gyricon, this new display technology was designed to mimic the properties of paper, but married with the capacity to display dynamic digital images. Sheridon envisioned the advent of paperless offices and sought commercial applications for Gyricon. [4] In 2003 Gyricon LLC was formed as a direct subsidiary of Xerox to commercialize the electronic paper technology developed at Xerox PARC. [5] Gyricon LLC's operations were short lived and in December 2005 Xerox closed the subsidiary company in a move to focus on licensing the technology instead. [6]
In 2005, Arizona State University (ASU) opened a 250,000 square foot facility dedicated to flexible display research named the ASU Flexible Display Center (FDC). ASU received $43.7 million from the U.S. Army Research Laboratory (ARL) towards the development of this research facility in February 2004. [7] A planned prototype device was slated for public demonstration later that year. [8] However, the project met a series of delays. In December 2008, ASU in partnership with Hewlett Packard demonstrated a prototype flexible e-paper from the Flexible Display Center at the university. [9] HP continued on with the research, and in 2010, showcased another demonstration. [10] However, due to limitations in technology, HP stated "[our company] doesn't actually see these panels being used in truly flexible or rollable displays, but instead sees them being used to simply make displays thinner and lighter." [10]
Between 2004–2008, ASU developed its first small-scale flexible displays. [11] Between 2008–2012, ARL committed to further sponsorship of ASU’s Flexible Display Center, which included an additional $50 million in research funding. [11] Although the U.S. Army funds ASU’s development of the flexible display, the center’s focus is on commercial applications. [12]
Plastic Logic is a company that develops and manufactures monochrome plastic flexible displays in various sizes based on its proprietary organic thin film transistor (OTFT) technology. They have also demonstrated their ability to produce colour displays with this technology, however they are currently not capable of manufacturing them on a large scale. [13] [14] [15] The displays are manufactured in the company's purpose-built factory in Dresden, Germany, which was the first factory of its kind to be built – dedicated to the high volume manufacture of organic electronics. [16] These flexible displays are cited as being "unbreakable", because they are made completely of plastic and do not contain glass. They are also lighter and thinner than glass-based displays and low-power. Applications of this flexible display technology include signage, [17] [18] wristwatches and wearable devices [19] as well as automotive and mobile devices. [20]
In 2004, a team led by Prof. Roel Vertegaal at Queen's University's Human Media Lab in Canada developed PaperWindows, [21] the first prototype bendable paper computer and first Organic User Interface. Since full-colour, US Letter-sized displays were not available at the time, PaperWindows deployed a form of active projection mapping of computer windows on real paper documents that worked together as one computer through 3D tracking. At a lecture to the Gyricon and Human-Computer Interaction teams at Xerox PARC on 4 May 2007, Prof. Vertegaal publicly introduced the term Organic User Interface (OUI) as a means of describing the implications of non-flat display technologies on user interfaces of the future: paper computers, flexible form factors for computing devices, but also encompassing rigid display objects of any shape, with wrap-around, skin-like displays. The lecture was published a year later as part of a special issue on Organic User Interfaces [22] in the Communications of the ACM. In May 2010, the Human Media Lab partnered with ASU's Flexible Display Center to produce PaperPhone, [23] the first flexible smartphone with a flexible electrophoretic display. PaperPhone used bend gestures for navigating contents. Since then, the Human Media Lab has partnered with Plastic Logic and Intel to introduce the first flexible tablet PC and multi-display e-paper computer, PaperTab, [24] at CES 2013, debuting the world's first actuated flexible smartphone prototype, MorePhone [25] in April 2013.
Since 2010, Sony Electronics, AU Optronics and LG Electronics have all expressed interest in developing flexible e-paper displays. [26] [27] However, only LG have formally announced plans for mass production of flexible e-paper displays. [28]
Research and development into flexible OLED displays largely began in the late 2000s with the main intentions of implementing this technology in mobile devices. However, this technology has recently made an appearance, to a moderate extent, in consumer television displays as well.
Nokia first conceptualized the application of flexible OLED displays in mobile phone with the Nokia Morph concept mobile phone. Released to the press in February 2008, the Morph concept was project Nokia had co-developed with the University of Cambridge. [29] With the Morph, Nokia intended to demonstrate their vision of future mobile devices to incorporate flexible and polymorphic designs; allowing the device to seamlessly change and match a variety of needs by the user within various environments. [30] Though the focus of the Morph was to demonstrate the potential of nanotechnology, it pioneered the concept of utilizing a flexible video display in a consumer electronics device. [30] Nokia renewed their interest in flexible mobile devices again in 2011 with the Nokia Kinetic concept. [31] Nokia unveiled the Kinetic flexible phone prototype at Nokia World 2011 in London, alongside Nokia’s new range of Windows Phone 7 devices. [32] The Kinetic proved to be a large departure from the Morph physically, but it still incorporated Nokia's vision of polymorphism in mobile devices. [31]
Sony Electronics has expressed interest for research and development towards a flexible display video display since 2005. [33] In partnership with RIKEN (the Institute of Physical and Chemical Research), Sony promised to commercialize this technology in TVs and cellphones sometime around 2010. [33] In May 2010 Sony showcased a rollable TFT-driven OLED display. [34]
In late 2010, Samsung Electronics announced the development of a prototype 4.5 inch flexible AMOLED display. [35] The prototype device was then showcased at Consumer Electronics Show 2011. [36] During the 2011 Q3 quarterly earnings call, Samsung’s vice president of investor relations, Robert Yi, confirmed the company’s intentions of applying the technology and releasing products utilizing it by early 2012. [37] In January 2012 Samsung acquired Liquavista, a company with expertise in manufacturing flexible displays, and announced plans to begin mass production by Q2 2012. [38] [39]
In January 2013, Samsung exposed its brand new, unnamed product during the company's keynote address at CES in Las Vegas. Brian Berkeley, the senior vice president of Samsung's display lab in San Jose, California had announced the development of flexible displays. He said "the technology will let the company's partners make bendable, rollable, and foldable displays," and he demonstrated how the new phone can be rollable and flexible during his speech. [40]
During Samsung's CES 2013 keynote presentation, two prototype mobile devices codenamed "Youm" that incorporated the flexible AMOLED display technology were shown to the public. [41] "Youm" has curved display screen, the use of OLED screen giving this phone deeper blacks and a higher overall contrast ratio with better power efficiency than traditional LCD displays. [42] Also this phone has the advantages of a rollable display; it is lighter, thinner, and more durable than LCD displays. Samsung stated that "Youm" panels will be seen in the market in a short time and production will commence in 2013. [43]
Samsung subsequently released the Galaxy Round, a smartphone with an inward curving screen and body, in October 2013. [44] One of the Youm concepts, which featured a curved screen edge used as a secondary area for notifications and shortcuts, was developed into the Galaxy Note Edge released in 2014. [45] In 2015, Samsung applied the technology to its flagship Galaxy S series with the release of the Galaxy S6 Edge, a variant of the S6 model with a screen sloped over both sides of the device. [46] During a developer conference in 2018, Samsung showed a foldable smartphone prototype, which was subsequently revealed in February 2019 as the Galaxy Fold. [47] [48]
The Flexible Display Center (FDC) at Arizona State University announced a continued effort in forwarding flexible displays in 2012. [49] On 30 May, in partnership with Army Research Lab scientists, ASU announced that it has successfully manufactured the world's largest flexible OLED display using thin-film transistor (TFTs) technology. [50] ASU intends the display to be used in "thin, lightweight, bendable and highly rugged devices." [50]
In January 2019, Chinese manufacturer Xiaomi showed a foldable smartphone prototype. [51] CEO Lin Bin of Xiaomi demoed the device in a video on the Weibo social network. The device features a large foldable display that curves 180 degrees inwards on two sides. The tablet turns into a smartphone, with a screen diagonal of 4,5 inch, adjusting the user interface on the fly.
Flexible displays have many advantages over glass: better durability, lighter weight, thinner as plastic, and can be perfectly curved and used in many devices. [52] Moreover, the major difference between glass and rollable display is that the display area of a rollable display can be bigger than the device itself; If a flexible device measuring, for example, 5 inches in diagonal and a roll of 7.5mm, it can be stored in a device smaller than the screen itself and close to 15mm in thickness. [53]
Flexible screens can open the doors to novel and alternative authentication schemes by emphasizing the interaction between the user and the touch screen. In “Bend Passwords: Using Gestures to Authenticate on Flexible Devices,” the authors introduce a new method called Bend Passwords where users perform bending gestures and deform the touch screen to unlock the phone. Their work and research points to Bend Passwords possibly becoming a new way to keep smartphones secure alongside the popularization of flexible displays. [54]
Flexible displays that use electronic paper technology commonly use Electrophoretic or Electrowetting technologies. However, each type of flexible electronic paper varies in specification due to different implementation techniques by different companies.
The flexible electronic paper display technology co-developed by Arizona State University and HP employs a manufacturing process developed by HP Labs called Self-Aligned Imprint Lithography (SAIL). [55] The screens are made by layering stacks of semi-conductor materials and metals between pliable plastic sheets. The stacks need to be perfectly aligned and stay that way. Alignment proves difficult during manufacturing when heat during manufacturing can deform the materials and when the resulting screen also needs to remain flexible. The SAIL process gets around this by ‘printing’ the semiconductor pattern on a fully composed substrate, so that the layers always remain in perfect alignment. The limitation of the material the screen is based on allows only a finite amount of full rolls, hence limiting its commercial application as a flexible display. [10] Specifications provided regarding the prototype display are as follows:
The flexible electronic paper display announced by AUO is unique as it is the only solar powered variant. A separate rechargeable battery is also attached when solar charging is unavailable. [56] Specifications [26]
Specifications: [57]
Model | Diagonal (in) | Radius of curvature* | Curved along its wider / shorter side? |
---|---|---|---|
Samsung Round | 5.7 | 400 millimetres (16 in) | shorter |
LG G Flex | 6 | 700 millimetres (28 in) | wider |
Samsung KN55S9C | 54.6 | 4,500 millimetres (180 in) | wider |
LG 55EA9800 | 54.6 | 5,000 millimetres (200 in) | wider |
*Lower is more sharply curved
Many of the e-paper based flexible displays are based on OLED technology and its variants. Though this technology is relatively new in comparison with e-paper based flexible displays, implementation of OLED flexible displays saw considerable growth in the last few years.
Specifications: [58]
In May 2011, Human Media Lab at Queen's University in Canada introduced PaperPhone, the first flexible smartphone, in partnership with the Arizona State University Flexible Display Center. [23] PaperPhone used 5 bend sensors to implement navigation of the user interface through bend gestures of corners and sides of the display. In January 2013, the Human Media Lab introduced the first flexible tablet PC, PaperTab, [24] in collaboration with Plastic Logic and Intel Labs, at CES. PaperTab is a multi-display environment in which each display represents a window, app or computer document. Displays are tracked in 3D to allow multidisplay operations, such as collate to enlarge the display space, or pointing with one display onto another to pull open a document file. In April 2013 in Paris, the Human Media Lab, in collaboration with Plastic Logic, unveiled the world's first actuated flexible smartphone prototype, MorePhone. [25] MorePhone actuates its body to notify users upon receiving a phone call or message.
Nokia introduced the Kinetic concept phone at Nokia World 2011 in London. [31] The flexible OLED display allows users to interact with the phone by twisting, bending, squeezing and folding in different manners across both the vertical and horizontal planes. [61] The technology journalist website Engadget described interactions such as "[when] bend the screen towards yourself, [the device] acts as a selection function, or zooms in on any pictures you're viewing." [62] Nokia envisioned this type of device to be available to consumers in "as little as three years", and claimed to already possess "the technology to produce it." [31]
At CES 2013, Samsung showcased the two handsets which incorporates AMOLED flexible display technology during its keynote presentation, the Youm and an unnamed Windows Phone 8 prototype device. [63] [64] The Youm possessed a static implementation of flexible AMOLED display technology, as its screen has a set curvature along one of its edges. [60] The benefit of the curvature allows users "to read text messages, stock tickers, and other notifications from the side of the device even if [the user] have a case covering the screen." [60] The unnamed Windows Phone 8 prototype device was composed of a solid base from that extends a flexible AMOLED display. [64] The AMOLED display itself bends and was described as "virtually unbreakable even when dropped" according to Samsung representatives. [41] Brian Berkeley, the senior vice president of Samsung Display, believes that this flexible form factor "will really begin to change how people interact with their devices, opening up new lifestyle possibilities ... [and] allow our partners to create a whole new ecosystem of devices." [41] The Youm's form factor was ultimately utilized on the Galaxy Note Edge, [45] and future Samsung Galaxy S series devices. [65]
ReFlex is a flexible smartphone created by Queen's University’s Human Media Lab. [66]
LG Electronics and Samsung Electronics both introduced curved OLED televisions with a curved display at CES 2013 hours apart from each other. [67] [68] Both companies recognized their respective curved OLED prototype television as a first-of-its-kind due to its flexed OLED display. [69] [70] The technology journalist website The Verge noted the subtle curve on 55" Samsung OLED TV allowed it to have a "more panoramic, more immersive viewing experience, and actually improves viewing angles from the side." [67] The experience was also shared viewing the curved 55" LG OLED TV. The LG set is also 3D capable, in addition to the curvature. [68]
Model | Diagonal (in) | Radius of curvature (mm)* |
---|---|---|
Samsung KN55S9C | 54.6 | 4,500 [71] |
LG 55EA9800 | 54.6 | 5,000 [71] |
*Lower is more sharply curved
Electronic paper or intelligent paper, is a display device that mimics the appearance of ordinary ink on paper. Unlike conventional flat panel displays that emit light, an electronic paper display reflects ambient light, like paper. This may make them more comfortable to read, and provide a wider viewing angle than most light-emitting displays. The contrast ratio in electronic displays available as of 2008 approaches newspaper, and newly developed displays are slightly better. An ideal e-paper display can be read in direct sunlight without the image appearing to fade.
A smartphone, often simply called a phone, is a mobile device that combines the functionality of a traditional mobile phone with advanced computing capabilities. It typically has a touchscreen interface, allowing users to access a wide range of applications and services, such as web browsing, email, and social media, as well as multimedia playback and streaming. Smartphones have built-in cameras, GPS navigation, and support for various communication methods, including voice calls, text messaging, and internet-based messaging apps.
An organic light-emitting diode (OLED), also known as organic electroluminescentdiode, is a type of light-emitting diode (LED) in which the emissive electroluminescent layer is an organic compound film that emits light in response to an electric current. This organic layer is situated between two electrodes; typically, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television screens, computer monitors, and portable systems such as smartphones and handheld game consoles. A major area of research is the development of white OLED devices for use in solid-state lighting applications.
A flat-panel display (FPD) is an electronic display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment.
A flexible organic light-emitting diode (FOLED) is a type of organic light-emitting diode (OLED) incorporating a flexible plastic substrate on which the electroluminescent organic semiconductor is deposited. This enables the device to be bent or rolled while still operating. Currently the focus of research in industrial and academic groups, flexible OLEDs form one method of fabricating a rollable display.
Plastic Logic Germany develops and manufactures electrophoretic displays (EPD), based on organic thin-film transistor (OTFT) technology, in Dresden, Germany.
In human–computer interaction, an organic user interface (OUI) is defined as a user interface with a non-flat display. After Engelbart and Sutherland's graphical user interface (GUI), which was based on the cathode ray tube (CRT), and Kay and Weiser's ubiquitous computing, which is based on the flat panel liquid-crystal display (LCD), OUI represents one possible third wave of display interaction paradigms, pertaining to multi-shaped and flexible displays. In an OUI, the display surface is always the focus of interaction, and may actively or passively change shape upon analog inputs. These inputs are provided through direct physical gestures, rather than through indirect point-and-click control. Note that the term "Organic" in OUI was derived from organic architecture, referring to the adoption of natural form to design a better fit with human ecology. The term also alludes to the use of organic electronics for this purpose.
AMOLED is a type of OLED display device technology. OLED describes a specific type of thin-film-display technology in which organic compounds form the electroluminescent material, and active matrix refers to the technology behind the addressing of pixels.
The form factor of a mobile phone is its size, shape, and style, as well as the layout and position of its major components.
Samsung GT-i8910 Omnia HD is a smartphone manufactured by Samsung Electronics, first announced at MWC 2009 on February 18, 2009. The device was the first phone capable of playing and recording 720p HD video. It runs on the S60 5th Edition (Symbian^1) platform, the only Samsung device to do so.
The Omnia series is a line of smartphones produced by Samsung Electronics. Omnia devices run either Microsoft's Windows Mobile 6.5, or Windows Phone 7 operating systems, and one Symbian device under the brand was also released.
PenTile matrix is a family of patented subpixel matrix schemes used in electronic device displays. PenTile is a trademark of Samsung. PenTile matrices are used in AMOLED and LCD displays.
Universal Display Corporation is a developer and manufacturer of organic light emitting diodes (OLED) technologies and materials as well as provider of services to the display and lighting industries. It is also an OLED research company. Founded in 1994, the company currently owns or has exclusive, co-exclusive or sole license rights with respect to more than 3,000 issued and pending patents worldwide for the commercialization of phosphorescent based OLEDs and also flexible, transparent and stacked OLEDs - for both display and lighting applications. Its phosphorescent OLED technologies and materials are licensed and supplied to companies such as Samsung, LG, AU Optronics CMEL, Pioneer, Panasonic Idemitsu OLED lighting and Konica Minolta.
MirrorLink is a device interoperability standard that offers integration between a smartphone and a car's infotainment system.
A phablet is a mobile device combining or straddling the size formats of smartphones and tablets. The word is a blend word of phone and tablet. The term is largely unused by the late 2010s, since average PDA sizes eventually morphed into small tablet sizes, up to 6.9 inches (180 mm), with wider aspect ratios.
Samsung Galaxy Round is an Android phablet smartphone produced by Samsung Electronics. Unveiled in October 2013, it is a curved variation of the Galaxy Note 3 that was distinguished by being the first commercially produced smartphone to feature a curved display. It launched exclusively on SK Telecom in South Korea on 10 October 2013.
The LG G Flex is an Android phablet developed and manufactured by LG. First unveiled by the company on October 27, 2013 for a release in South Korea, and carrying similarities to its G2 model, the smartphone is the company's first to incorporate a flexible display, along with a "self-healing" rear cover which can repair minor abrasions on its own.
The Samsung Galaxy Note Edge is an Android phablet produced by Samsung Electronics. Unveiled during a Samsung press conference at IFA Berlin on September 3, 2014, alongside its sister, the Galaxy Note 4, it is distinguished by a display that curves across the right side of the device, which can be used as a sidebar to display application shortcuts, a virtual camera shutter button, notifications, and other information.
A foldable smartphone is a smartphone with a folding form factor. It is reminiscent of the clamshell design of many earlier feature phones. Some variants of the concept use multiple touchscreen panels on a hinge, while other designs utilise a flexible display. Concepts of such devices date back as early as Nokia's "Morph" concept in 2008, and a concept presented by Samsung Electronics in 2013, while the first commercially available folding smartphones with OLED displays began to emerge in November 2018.
BOE Technology Group Co., Ltd., or Jingdongfang, is a Chinese electronic components producer founded in April 1993. Its core businesses are interface devices, smart IoT systems and smart medicine and engineering integration. BOE is one of the world's largest manufacturers of LCD, OLEDs and flexible displays.
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