Electronic paper
Encyclopedia
Electronic paper, e-paper and electronic ink are a range of display technology which are designed to mimic the appearance of ordinary ink
on paper
. Unlike conventional backlit
flat panel display
s, electronic paper displays reflect light like ordinary paper. Many of the technologies can hold static text and images indefinitely without using electricity, while allowing images to be changed later. Flexible electronic paper uses plastic substrates and plastic electronics for the display backplane.
Electronic paper is often considered to be more comfortable to read than conventional displays. This is due to the stable image, which has no need to be refreshed constantly, a wider viewing angle, and that it reflects ambient light rather than emitting its own light. An ideal e-paper display can be read in direct sunlight without the image appearing to fade. The contrast ratio
in available displays as of 2008 might be described as similar to that of newspaper, though newly-developed displays are slightly better. There is ongoing competition among manufacturers to provide full-color ability.
Applications of electronic visual display
s include electronic pricing labels in retail shops, and digital signage
, time tables at bus stations, electronic billboards, mobile phone displays, and e-readers
able to display digital versions of books and e-paper magazines. Electronic paper should not be confused with digital paper
, which is a pad to create handwritten digital documents with a digital pen.
's Palo Alto Research Center
. The first electronic paper, called Gyricon
, consisted of polyethylene spheres between 75 and 106 micrometres across. Each sphere is a janus particle
composed of negatively charged black plastic on one side and positively charged white plastic on the other (each bead is thus a dipole
). The spheres are embedded in a transparent silicone sheet, with each sphere suspended in a bubble of oil so that they can rotate freely. The polarity of the voltage applied to each pair of electrodes then determines whether the white or black side is face-up, thus giving the pixel a white or black appearance.
At the FPD 2008 exhibition, Japanese company Soken has demonstrated a wall with electronic wall-paper using this technology.
In the simplest implementation of an electrophoretic display, titanium dioxide
(titania) particles approximately one micrometer in diameter are dispersed in a hydrocarbon oil. A dark-colored dye is also added to the oil, along with surfactant
s and charging agents that cause the particles to take on an electric charge. This mixture is placed between two parallel, conductive plates separated by a gap of 10 to 100 micrometre
s. When a voltage is applied across the two plates, the particles will migrate electrophoretically
to the plate bearing the opposite charge from that on the particles. When the particles are located at the front (viewing) side of the display, it appears white, because light is scattered back to the viewer by the high-index titania particles. When the particles are located at the rear side of the display, it appears dark, because the incident light is absorbed by the colored dye. If the rear electrode is divided into a number of small picture elements (pixel
s), then an image can be formed by applying the appropriate voltage to each region of the display to create a pattern of reflecting and absorbing regions.
Electrophoretic displays are considered prime examples of the electronic paper category, because of their paper-like appearance and low power consumption.
Examples of commercial electrophoretic displays include the high-resolution active matrix
displays used in the Amazon Kindle
, Barnes & Noble Nook
, Sony Librie, Sony Reader
, and iRex iLiad e-readers. These displays are constructed from an electrophoretic imaging film manufactured by E Ink Corporation
.
The EPD technology has been developed also by Sipix and Bridgestone
/Delta.
SiPix Imaging Inc. is now part of AU Optronics Corp, one of the three largest LCD-panel manufacturers in the world. Other than E-Ink's 0.04mm-diameter micro-capsule structure, Sipix's is 0.15mm-diameter microcup.
On the other side, Bridgestone
Corp.'s Advanced Materials Division has been cooperating with Delta Optoelectronics Inc. in developing the Quick Response Liquid Powder Display (QR-LPD) technology. The Motorola MOTOFONE F3 was the first mobile phone to use the technology, in an effort to help eliminate glare from direct sunlight during outdoor use.
Electrophoretic displays can be manufactured using the Electronics on Plastic by Laser Release (EPLaR)
process developed by Philips Research
to enable existing AM-LCD manufacturing plants to create flexible plastic displays.
An electrophoretic display forms visible images by rearranging charged pigment particles using an applied electric field
In the 1990s another type of electronic paper was invented by Joseph Jacobson
, who later co-founded the E Ink Corporation
which formed a partnership with Philips Components
two years later to develop and market the technology. In 2005, Philips sold the electronic paper business as well as its related patents to Prime View International. This used tiny microcapsules filled with electrically charged white particles suspended in a colored oil
. In early versions, the underlying circuitry controlled whether the white particles were at the top of the capsule (so it looked white to the viewer) or at the bottom of the capsule (so the viewer saw the color of the oil). This was essentially a reintroduction of the well-known electrophoretic
display technology, but the use of microcapsules allowed the display to be used on flexible plastic sheets instead of glass.
One early version of electronic paper consists of a sheet of very small transparent capsules, each about 40 micrometre
s across. Each capsule contains an oily solution containing black dye (the electronic ink), with numerous white titanium dioxide
particles suspended within. The particles are slightly negatively charged
, and each one is naturally white.
The microcapsules are held in a layer of liquid
polymer
, sandwiched between two arrays of electrodes, the upper of which is made transparent. The two arrays are aligned so that the sheet is divided into pixels, which each pixel corresponding to a pair of electrodes situated either side of the sheet. The sheet is laminated with transparent plastic for protection, resulting in an overall thickness of 80 micrometres, or twice that of ordinary paper.
The network of electrodes is connected to display circuitry, which turns the electronic ink 'on' and 'off' at specific pixels by applying a voltage to specific pairs of electrodes. Applying a negative charge to the surface electrode repels the particles to the bottom of local capsules, forcing the black dye to the surface and giving the pixel a black appearance. Reversing the voltage has the opposite effect - the particles are forced from the surface, giving the pixel a white appearance. A more recent incarnation of this concept requires only one layer of electrodes beneath the microcapsules.
When a voltage is applied between the electrode and the water, the interfacial tension between the water and the coating changes. As a result the stacked state is no longer stable, causing the water to move the oil aside.
This results in a partly transparent pixel, or, if a reflective white surface is used under the switchable element, a white pixel. Because of the small size of the pixel, the user only experiences the average reflection, which means that a high-brightness, high-contrast switchable element is obtained, which forms the basis of the reflective display.
Displays based on electro-wetting
have several attractive features. The switching between white and coloured reflection is fast enough to display video content.
It is a low-power and low-voltage technology, and displays based on the effect can be made flat and thin. The reflectivity and contrast are better than or equal to those of other reflective display types and are approaching those of paper.
In addition, the technology offers a unique path toward high-brightness full-colour displays, leading to displays that are four times brighter than reflective LCDs and twice as bright as other emerging technologies.
Instead of using red, green and blue (RGB) filters or alternating segments of the three primary colours, which effectively result in only one third of the display reflecting light in the desired colour, electro-wetting allows for a system in which one sub-pixel is able to switch two different colours independently.
This results in the availability of two thirds of the display area to reflect light in any desired colour. This is achieved by building up a pixel with a stack of two independently controllable coloured oil films plus a colour filter.
The colours used are cyan, magenta and yellow, which is a so-called subtractive system, comparable to the principle used in inkjet printing for example. Compared to LCD another factor two in brightness is gained because no polarisers are required.
Examples of commercial electrowetting displays include Liquavista
, ITRI
, PVI and ADT
.
The core technology was invented at the Novel Devices Laboratory at the University of Cincinnati
. The technology is currently being commercialized by Gamma Dynamics.
embedded into flexible substrates, including attempts to build them into conventional paper.
Simple color e-paper consists of a thin colored optical filter added to the monochrome technology described above. The array of pixels is divided into triad
s, typically consisting of the standard cyan, magenta and yellow, in the same way as CRT
monitors (although using subtractive primary colors as opposed to additive primary colors). The display is then controlled like any other electronic color display.
Examples of electrochromic displays include Acreo, Ajjer, Aveso and Ntera.
Another limit is that a shadow of an image may be visible after refreshing parts of the screen. Such shadows are termed "ghost images", and the effect is termed "ghosting". This effect is reminiscent of screen burn-in but, unlike it, is solved after the screen is refreshed several times. Turning every pixel white, then black, then white, helps normalize the contrast of the pixels. This is why several devices with this technology "flash" the entire screen white and black when loading a new image.
Electronic paper is still a topic in the R&D community and remains under development for manufacturability, marketability, and reliability considerations.
Electronic ink can be applied to flexible or rigid materials. For flexible displays, the base requires a thin, flexible material tough enough to withstand considerable wear, such as extremely thin plastic. The method of how the inks are encapsulated and then applied to the substrate is what distinguishes each company from others. These processes are complex and are carefully guarded industry secrets. Nevertheless, making electronic paper promises to be less complex and costly than making traditional LCDs.
There are many approaches to electronic paper, with many companies developing technology in this area. Other technologies being applied to electronic paper include modifications of liquid crystal display
s, electrochromic displays, and the electronic equivalent of an Etch A Sketch
at Kyushu University. Advantages of electronic paper includes low power usage (power is only drawn when the display is updated), flexibility and better readability than most displays. Electronic ink can be printed on any surface, including walls, billboards, product labels and T-shirts. The ink's flexibility would also make it possible to develop rollable display
s for electronic devices.
Ink
Ink is a liquid or paste that contains pigments and/or dyes and is used to color a surface to produce an image, text, or design. Ink is used for drawing and/or writing with a pen, brush, or quill...
on paper
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
. Unlike conventional backlit
Backlight
A backlight is a form of illumination used in liquid crystal displays . As LCDs do not produce light themselves , they need illumination to produce a visible image...
flat panel display
Flat panel display
Flat panel displays encompass a growing number of electronic visual display technologies. They are far lighter and thinner than traditional television sets and video displays that use cathode ray tubes , and are usually less than thick...
s, electronic paper displays reflect light like ordinary paper. Many of the technologies can hold static text and images indefinitely without using electricity, while allowing images to be changed later. Flexible electronic paper uses plastic substrates and plastic electronics for the display backplane.
Electronic paper is often considered to be more comfortable to read than conventional displays. This is due to the stable image, which has no need to be refreshed constantly, a wider viewing angle, and that it reflects ambient light rather than emitting its own light. An ideal e-paper display can be read in direct sunlight without the image appearing to fade. The contrast ratio
Contrast ratio
The contrast ratio is a property of a display system, defined as the ratio of the luminance of the brightest color to that of the darkest color that the system is capable of producing...
in available displays as of 2008 might be described as similar to that of newspaper, though newly-developed displays are slightly better. There is ongoing competition among manufacturers to provide full-color ability.
Applications of electronic visual display
Electronic visual display
An electronic visual display is display technology which incorporates flat panel displays, performs as a video display, output device for presentation of images transmitted electronically, for visual reception, without producing a permanent record....
s include electronic pricing labels in retail shops, and digital signage
Digital signage
Digital signage is a form of electronic display that shows television programming, menus, information, advertising and other messages. Digital signs can be found in public and private environments, such as retail stores, hotels, restaurants and corporate buildings.Digital signage Displays are most...
, time tables at bus stations, electronic billboards, mobile phone displays, and e-readers
E-book
An electronic book is a book-length publication in digital form, consisting of text, images, or both, and produced on, published through, and readable on computers or other electronic devices. Sometimes the equivalent of a conventional printed book, e-books can also be born digital...
able to display digital versions of books and e-paper magazines. Electronic paper should not be confused with digital paper
Digital paper
Digital paper, also known as interactive paper, is patterned paper used in conjunction with a digital pen to create handwritten digital documents. The printed dot pattern uniquely identifies the position coordinates on the paper...
, which is a pad to create handwritten digital documents with a digital pen.
Gyricon
Electronic paper was first developed in the 1970s by Nick Sheridon at XeroxXerox
Xerox Corporation is an American multinational document management corporation that produced and sells a range of color and black-and-white printers, multifunction systems, photo copiers, digital production printing presses, and related consulting services and supplies...
's Palo Alto Research Center
Xerox PARC
PARC , formerly Xerox PARC, is a research and co-development company in Palo Alto, California, with a distinguished reputation for its contributions to information technology and hardware systems....
. The first electronic paper, called Gyricon
Gyricon
Gyricon is a type of electronic paper developed at the Xerox PARC . It has many of the same properties as paper: It's flexible, contains an image, and is viewable from a wide angle, but it can be erased and written thousands of times....
, consisted of polyethylene spheres between 75 and 106 micrometres across. Each sphere is a janus particle
Janus particle
Originally the term Janus particle was coined by C. Casagrande et al. in 1988 to describe spherical glass particles with one of the hemispheres hydrophilic and the other hydrophobic. In that work the amphiphilic beads were synthesized by protecting one hemisphere with varnish and chemically...
composed of negatively charged black plastic on one side and positively charged white plastic on the other (each bead is thus a dipole
Dipole
In physics, there are several kinds of dipoles:*An electric dipole is a separation of positive and negative charges. The simplest example of this is a pair of electric charges of equal magnitude but opposite sign, separated by some distance. A permanent electric dipole is called an electret.*A...
). The spheres are embedded in a transparent silicone sheet, with each sphere suspended in a bubble of oil so that they can rotate freely. The polarity of the voltage applied to each pair of electrodes then determines whether the white or black side is face-up, thus giving the pixel a white or black appearance.
At the FPD 2008 exhibition, Japanese company Soken has demonstrated a wall with electronic wall-paper using this technology.
Electrophoretic
Titanium dioxide
Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of...
(titania) particles approximately one micrometer in diameter are dispersed in a hydrocarbon oil. A dark-colored dye is also added to the oil, along with surfactant
Surfactant
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...
s and charging agents that cause the particles to take on an electric charge. This mixture is placed between two parallel, conductive plates separated by a gap of 10 to 100 micrometre
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
s. When a voltage is applied across the two plates, the particles will migrate electrophoretically
Electrophoresis
Electrophoresis, also called cataphoresis, is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. This electrokinetic phenomenon was observed for the first time in 1807 by Reuss , who noticed that the application of a constant electric...
to the plate bearing the opposite charge from that on the particles. When the particles are located at the front (viewing) side of the display, it appears white, because light is scattered back to the viewer by the high-index titania particles. When the particles are located at the rear side of the display, it appears dark, because the incident light is absorbed by the colored dye. If the rear electrode is divided into a number of small picture elements (pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
s), then an image can be formed by applying the appropriate voltage to each region of the display to create a pattern of reflecting and absorbing regions.
Electrophoretic displays are considered prime examples of the electronic paper category, because of their paper-like appearance and low power consumption.
Examples of commercial electrophoretic displays include the high-resolution active matrix
Active matrix
Active matrix is a type of addressing scheme used in flat panel displays. The term describes a method of switching individual elements of a flat panel display, using a CdSe or Silicon-based thin-film transistor for each pixel...
displays used in the Amazon Kindle
Amazon Kindle
The Amazon Kindle is an e-book reader developed by Amazon.com subsidiary Lab126 which uses wireless connectivity to enable users to shop for, download, browse, and read e-books, newspapers, magazines, blogs, and other digital media...
, Barnes & Noble Nook
Barnes & Noble Nook
The Barnes & Noble Nook is a brand of electronic-book reader developed by American book retailer Barnes & Noble, based on the Android platform. The original device was announced in the United States in October 2009, and was released the next month...
, Sony Librie, Sony Reader
Sony Reader
The Sony Reader is a line of e-book readers manufactured by Sony. It uses an electronic paper display developed by E Ink Corporation, is viewable in direct sunlight, requires no power to maintain a static image, and is usable in portrait or landscape orientation.Sony sells e-books for the Reader...
, and iRex iLiad e-readers. These displays are constructed from an electrophoretic imaging film manufactured by E Ink Corporation
E Ink Corporation
E Ink Corporation is a privately held manufacturer of electrophoretic displays , a kind of electronic paper. E Ink is located in Cambridge, Massachusetts, and was co-founded in 1997 by Joseph Jacobson, a professor in the MIT Media Lab. Two years later, E Ink partnered with Philips to develop and...
.
The EPD technology has been developed also by Sipix and Bridgestone
Bridgestone
The is a multinational rubber conglomerate founded in 1931 by in the city of Kurume, Fukuoka, Japan. The name Bridgestone comes from a calque translation and transposition of ishibashi, meaning "stone bridge" in Japanese....
/Delta.
SiPix Imaging Inc. is now part of AU Optronics Corp, one of the three largest LCD-panel manufacturers in the world. Other than E-Ink's 0.04mm-diameter micro-capsule structure, Sipix's is 0.15mm-diameter microcup.
On the other side, Bridgestone
Bridgestone
The is a multinational rubber conglomerate founded in 1931 by in the city of Kurume, Fukuoka, Japan. The name Bridgestone comes from a calque translation and transposition of ishibashi, meaning "stone bridge" in Japanese....
Corp.'s Advanced Materials Division has been cooperating with Delta Optoelectronics Inc. in developing the Quick Response Liquid Powder Display (QR-LPD) technology. The Motorola MOTOFONE F3 was the first mobile phone to use the technology, in an effort to help eliminate glare from direct sunlight during outdoor use.
Electrophoretic displays can be manufactured using the Electronics on Plastic by Laser Release (EPLaR)
EPLaR
Electronics on Plastic by Laser Release is a method for manufacturing flexible electrophoretic displays using conventional AM-LCD manufacturing equipment avoiding the need to build new factories...
process developed by Philips Research
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....
to enable existing AM-LCD manufacturing plants to create flexible plastic displays.
Electrophoretic display
Electric field
In physics, an electric field surrounds electrically charged particles and time-varying magnetic fields. The electric field depicts the force exerted on other electrically charged objects by the electrically charged particle the field is surrounding...
In the 1990s another type of electronic paper was invented by Joseph Jacobson
Joseph Jacobson
Joseph Jacobson, a native and resident of Newton, Massachusetts, is a tenured professor and head of the Molecular Machines group at the Center for Bits and Atoms at the MIT Media Lab...
, who later co-founded the E Ink Corporation
E Ink Corporation
E Ink Corporation is a privately held manufacturer of electrophoretic displays , a kind of electronic paper. E Ink is located in Cambridge, Massachusetts, and was co-founded in 1997 by Joseph Jacobson, a professor in the MIT Media Lab. Two years later, E Ink partnered with Philips to develop and...
which formed a partnership with Philips Components
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....
two years later to develop and market the technology. In 2005, Philips sold the electronic paper business as well as its related patents to Prime View International. This used tiny microcapsules filled with electrically charged white particles suspended in a colored oil
Mineral oil
A mineral oil is any of various colorless, odorless, light mixtures of alkanes in the C15 to C40 range from a non-vegetable source, particularly a distillate of petroleum....
. In early versions, the underlying circuitry controlled whether the white particles were at the top of the capsule (so it looked white to the viewer) or at the bottom of the capsule (so the viewer saw the color of the oil). This was essentially a reintroduction of the well-known electrophoretic
Electrophoresis
Electrophoresis, also called cataphoresis, is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. This electrokinetic phenomenon was observed for the first time in 1807 by Reuss , who noticed that the application of a constant electric...
display technology, but the use of microcapsules allowed the display to be used on flexible plastic sheets instead of glass.
One early version of electronic paper consists of a sheet of very small transparent capsules, each about 40 micrometre
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
s across. Each capsule contains an oily solution containing black dye (the electronic ink), with numerous white titanium dioxide
Titanium dioxide
Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of...
particles suspended within. The particles are slightly negatively charged
Electric charge
Electric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
, and each one is naturally white.
The microcapsules are held in a layer of liquid
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...
polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
, sandwiched between two arrays of electrodes, the upper of which is made transparent. The two arrays are aligned so that the sheet is divided into pixels, which each pixel corresponding to a pair of electrodes situated either side of the sheet. The sheet is laminated with transparent plastic for protection, resulting in an overall thickness of 80 micrometres, or twice that of ordinary paper.
The network of electrodes is connected to display circuitry, which turns the electronic ink 'on' and 'off' at specific pixels by applying a voltage to specific pairs of electrodes. Applying a negative charge to the surface electrode repels the particles to the bottom of local capsules, forcing the black dye to the surface and giving the pixel a black appearance. Reversing the voltage has the opposite effect - the particles are forced from the surface, giving the pixel a white appearance. A more recent incarnation of this concept requires only one layer of electrodes beneath the microcapsules.
Electrowetting
Electro-wetting display (EWD) is based on controlling the shape of a confined water/oil interface by an applied voltage. With no voltage applied, the (coloured) oil forms a flat film between the water and a hydrophobic (water-repellent) insulating coating of an electrode, resulting in a coloured pixel.When a voltage is applied between the electrode and the water, the interfacial tension between the water and the coating changes. As a result the stacked state is no longer stable, causing the water to move the oil aside.
This results in a partly transparent pixel, or, if a reflective white surface is used under the switchable element, a white pixel. Because of the small size of the pixel, the user only experiences the average reflection, which means that a high-brightness, high-contrast switchable element is obtained, which forms the basis of the reflective display.
Displays based on electro-wetting
Electrowetting
Electrowetting is the modification of the wetting properties of a surface with an applied electric field.-History:...
have several attractive features. The switching between white and coloured reflection is fast enough to display video content.
It is a low-power and low-voltage technology, and displays based on the effect can be made flat and thin. The reflectivity and contrast are better than or equal to those of other reflective display types and are approaching those of paper.
In addition, the technology offers a unique path toward high-brightness full-colour displays, leading to displays that are four times brighter than reflective LCDs and twice as bright as other emerging technologies.
Instead of using red, green and blue (RGB) filters or alternating segments of the three primary colours, which effectively result in only one third of the display reflecting light in the desired colour, electro-wetting allows for a system in which one sub-pixel is able to switch two different colours independently.
This results in the availability of two thirds of the display area to reflect light in any desired colour. This is achieved by building up a pixel with a stack of two independently controllable coloured oil films plus a colour filter.
The colours used are cyan, magenta and yellow, which is a so-called subtractive system, comparable to the principle used in inkjet printing for example. Compared to LCD another factor two in brightness is gained because no polarisers are required.
Examples of commercial electrowetting displays include Liquavista
Liquavista
Liquavista is a Dutch company founded in 2006 as a spin-out from Philips. It develops colour e-paper video screens that can work with or without a backlight using electrowetting technology...
, ITRI
Itri
Itri is a small city and comune in the central Italian region of Latium and the Province of Latina.Itri is an agricultural centre divided in two parts by a small river, the Pontone. It lies in a valley between the Monti Aurunci and the sea, not far from the Gulf of Gaeta...
, PVI and ADT
ADT
ADT, as an acronym, may refer to:*Abstract data type, a computer programming term*Alternating decision tree, another term in computer programming*Algebraic data type, a term from functional programming...
.
Electrofluidic
Electrofluidic displays are a variation of an electrowetting display. Electrofluidic displays place an aqueous pigment dispersion inside a tiny reservoir. The reservoir comprises <5-10% of the viewable pixel area and therefore the pigment is substantially hidden from view. Voltage is used to electromechanically pull the pigment out of the reservoir and spread it as a film directly behind the viewing substrate. As a result, the display takes on color and brightness similar to that of conventional pigments printed on paper. When voltage is removed liquid surface tension causes the pigment dispersion to rapidly recoil into the reservoir. As reported in the May 2009 Issue of Nature Photonics, the technology can potentially provide >85% white state reflectance for electronic paper.The core technology was invented at the Novel Devices Laboratory at the University of Cincinnati
University of Cincinnati
The University of Cincinnati is a comprehensive public research university in Cincinnati, Ohio, and a part of the University System of Ohio....
. The technology is currently being commercialized by Gamma Dynamics.
Other bistable displays
- QualcommQualcommQualcomm is an American global telecommunication corporation that designs, manufactures and markets digital wireless telecommunications products and services based on its code division multiple access technology and other technologies. Headquartered in San Diego, CA, USA...
, manufacturer of "Mirasol" interferometric modulator displayInterferometric modulator displayInterferometric modulator display is a technology used in electronic visual displays that can create various colors via interference of reflected light... - Kent Displays, manufacturer of cholesteric liquid crystal display (ChLCD)
- Nemoptic, nematic materials
- TRED
Other technologies
Other research efforts into e-paper have involved using organic transistorsOFET
An organic field-effect transistor is a field effect transistor using an organic semiconductor in its channel. OFETs can be prepared either by vacuum evaporation of small molecules, by solution-casting of polymers or small molecules, or by mechanical transfer of a peeled single-crystalline organic...
embedded into flexible substrates, including attempts to build them into conventional paper.
Simple color e-paper consists of a thin colored optical filter added to the monochrome technology described above. The array of pixels is divided into triad
Triad (computers)
In CRT or computer terminology, a triad is a group of three phosphor dots coloured red, green, and blue on the inside of the CRT display of a computer monitor or television set. By directing differing intensities of electron beams onto the three phosphor dots, the triad will display a colour by...
s, typically consisting of the standard cyan, magenta and yellow, in the same way as CRT
CRT
-Medicine:* Capillary refill time, the rate at with blood refills empty capillaries* Cognitive Retention Therapy, a dementia treatment* Cardiac resynchronization therapy, a treatment for heart failure** CRT-D, an implanted cardiac resynchronization device...
monitors (although using subtractive primary colors as opposed to additive primary colors). The display is then controlled like any other electronic color display.
Examples of electrochromic displays include Acreo, Ajjer, Aveso and Ntera.
Disadvantages
Electronic paper technologies have a very low refresh rate compared to other low-power display technologies, such as LCD. This prevents producers from implementing sophisticated interactive applications (using fast moving menus, mouse pointers or scrolling) like those which are possible on mobile devices. An example of this limit is that a document cannot be smoothly zoomed without either extreme blurring during the transition or a very slow zoom.Another limit is that a shadow of an image may be visible after refreshing parts of the screen. Such shadows are termed "ghost images", and the effect is termed "ghosting". This effect is reminiscent of screen burn-in but, unlike it, is solved after the screen is refreshed several times. Turning every pixel white, then black, then white, helps normalize the contrast of the pixels. This is why several devices with this technology "flash" the entire screen white and black when loading a new image.
Electronic paper is still a topic in the R&D community and remains under development for manufacturability, marketability, and reliability considerations.
Applications
Several companies are simultaneously developing electronic paper and ink. While the technologies used by each company provide many of the same features, each has its own distinct technological advantages. All electronic paper technologies face the following general challenges:- A method for encapsulation
- An ink or active material to fill the encapsulation
- Electronics to activate the ink
Electronic ink can be applied to flexible or rigid materials. For flexible displays, the base requires a thin, flexible material tough enough to withstand considerable wear, such as extremely thin plastic. The method of how the inks are encapsulated and then applied to the substrate is what distinguishes each company from others. These processes are complex and are carefully guarded industry secrets. Nevertheless, making electronic paper promises to be less complex and costly than making traditional LCDs.
There are many approaches to electronic paper, with many companies developing technology in this area. Other technologies being applied to electronic paper include modifications of liquid crystal display
Liquid crystal display
A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....
s, electrochromic displays, and the electronic equivalent of an Etch A Sketch
Etch A Sketch
Etch A Sketch is a registered trademark for a mechanical drawing toy manufactured by the Ohio Art Company.An Etch A Sketch is a thick, flat gray screen in a plastic frame. There are two knobs on the front of the frame in the lower corners. Twisting the knobs moves a stylus that displaces aluminium...
at Kyushu University. Advantages of electronic paper includes low power usage (power is only drawn when the display is updated), flexibility and better readability than most displays. Electronic ink can be printed on any surface, including walls, billboards, product labels and T-shirts. The ink's flexibility would also make it possible to develop rollable display
Rollable display
A rollable display is a flexible display device which can be rolled up into a scroll.Technologies involved in building a rollable display include electronic ink, Gyricon, and OLED.Electronic paper displays which can be rolled up have been developed by E Ink...
s for electronic devices.
Wristwatches
- In December 2005 SeikoSeiko, more commonly known simply as Seiko , is a Japanese watch company.-History and ongoing developments:The company was founded in 1881, when Kintarō Hattori opened a watch and jewelry shop called in the Ginza area of Tokyo, Japan. Eleven years later, in 1892, he began to produce clocks under the...
released the first electronic ink based watch called the Spectrum SVRD001 wristwatch, which has a flexibleRollable displayA rollable display is a flexible display device which can be rolled up into a scroll.Technologies involved in building a rollable display include electronic ink, Gyricon, and OLED.Electronic paper displays which can be rolled up have been developed by E Ink...
electrophoretic display and in March 2010 Seiko released a second generation of this famous e-ink watch with an active matrix display.
e-Books
- In 2004 SonySony, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
released Librié EBR-1000EPSony Librie EBR-1000EP- Overview :The Sony LIBRIé EBR-1000EP is a Japan only e-book display device in April 2004, two years prior its world successor Sony Reader.- Features :The 1000EP possesses the following specifications....
in Japan, the first e-book reader with an electronic paper display. In September 2006 SonySony, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
released the PRS-500 Sony ReaderSony ReaderThe Sony Reader is a line of e-book readers manufactured by Sony. It uses an electronic paper display developed by E Ink Corporation, is viewable in direct sunlight, requires no power to maintain a static image, and is usable in portrait or landscape orientation.Sony sells e-books for the Reader...
e-book reader in the USA. On October 2, 2007, Sony announced the PRS-505, an updated version of the Reader. In November 2008, Sony released the PRS-700BC which incorporated a backlight and a touchscreen.
- In late 2007, Amazon began producing and marketing the Amazon KindleAmazon KindleThe Amazon Kindle is an e-book reader developed by Amazon.com subsidiary Lab126 which uses wireless connectivity to enable users to shop for, download, browse, and read e-books, newspapers, magazines, blogs, and other digital media...
, an e-book reader with an e-paper display. In February 2009, Amazon released the Kindle 2 and in May 2009 the larger Kindle DX was announced. In July 2010 the third generation Kindle was announced.
- In November 2009 Barnes and Noble launched the Barnes & Noble NookBarnes & Noble NookThe Barnes & Noble Nook is a brand of electronic-book reader developed by American book retailer Barnes & Noble, based on the Android platform. The original device was announced in the United States in October 2009, and was released the next month...
, running an Android operating system. It differs from other big name readers in having a replaceable battery, and a separate touch-screen color LCD below the main electronic paper reading screen.
Newspapers
- In February 2006, the FlemishFlandersFlanders is the community of the Flemings but also one of the institutions in Belgium, and a geographical region located in parts of present-day Belgium, France and the Netherlands. "Flanders" can also refer to the northern part of Belgium that contains Brussels, Bruges, Ghent and Antwerp...
daily De TijdDe TijdDe Tijd , formerly De Financieel-Economische Tijd , is a Belgian broadsheet newspaper that mainly focuses on business and economics...
distributed an electronic version of the paper to select subscribers in a limited marketing study, using a pre-release version of the iRex iLiad. This was the first recorded application of electronic ink to newspaper publishing.
- In September 2007, the FrenchFrench languageFrench is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
daily Les Échos announced the official launch of an electronic version of the paper on a subscription basis. Two offers are available, combining a one year subscription and a reading device. One interesting point of the offer is the choice of a light (176g) reading device (adapted for Les Echos by Ganaxa) or the iRex iLiad. Two different processing platforms are used to deliver readable information of the daily, one based on the newly developed GPP electronic ink platform from Ganaxa, and the other one developed internally by Les Echos.
Displays embedded in smart cards
- Flexible display cards enable financial payment cardholders to generate a one-time passwordOne-time passwordA one-time password is a password that is valid for only one login session or transaction. OTPs avoid a number of shortcomings that are associated with traditional passwords. The most important shortcoming that is addressed by OTPs is that, in contrast to static passwords, they are not vulnerable...
to reduce online bankingOnline bankingOnline banking allows customers to conduct financial transactions on a secure website operated by their retail or virtual bank, credit union or building society.-Features:...
and transaction fraud. Electronic paper could offer a flat and thin alternative to existing key fob tokens for data security. The world’s first ISO compliant smart cardSmart cardA smart card, chip card, or integrated circuit card , is any pocket-sized card with embedded integrated circuits. A smart card or microprocessor cards contain volatile memory and microprocessor components. The card is made of plastic, generally polyvinyl chloride, but sometimes acrylonitrile...
with an embedded display was developed by Innovative Card Technologies and nCryptone in 2005. The cards were manufactured by Nagra ID.
Status displays
- Some devices, like USB flash driveUSB flash driveA flash drive is a data storage device that consists of flash memory with an integrated Universal Serial Bus interface. flash drives are typically removable and rewritable, and physically much smaller than a floppy disk. Most weigh less than 30 g...
s, have used electronic paper to display status information, such as available storage space.
Mobile phones
- Motorola's low-cost mobile phone, the Motorola F3, also uses an alphanumeric black/white electrophoretic display.
- The Samsung Alias 2 mobile phone incorporates electronic ink from E Ink into the keypad, which allows the keypad to change character sets and orientation while in different display modes.
Electronic shelf labels
- E-Paper based electronic shelf labels (ESL) are used to digitally show the prices at retail stores. Electronic paper based labels are updated via two-way radio. Labels from MariSense use E-Ink display technology.
Other
Other proposed applications include cloths, digital photo frames, information boards and simply keyboards (useful for less represented languages or special non alphabetical applications like video editing or games).Display manufacturers
- Delta ElectronicsDelta ElectronicsDelta Electronics, Inc., founded in 1971, is the world's largest provider of switching power supplies and DC brushless fans, as well as a major source for power management solutions, components, visual displays, industrial automation, networking products, and renewable energy solutions...
- LGLGLG may refer to:*LG Corp., a South Korean electronics and petrochemicals conglomerate*LG Electronics, an affiliate of the South Korean LG Group which produces electronic products* Lawrence Graham, a London headquartered firm of business lawyers...
- NECNEC, a Japanese multinational IT company, has its headquarters in Minato, Tokyo, Japan. NEC, part of the Sumitomo Group, provides information technology and network solutions to business enterprises, communications services providers and government....
- Plastic LogicPlastic LogicPlastic Logic is a spin-off company from Cambridge University's Cavendish Laboratory and specializes in polymer transistors and electronics.The firm was founded in 2000....
- E Ink HoldingsE Ink CorporationE Ink Corporation is a privately held manufacturer of electrophoretic displays , a kind of electronic paper. E Ink is located in Cambridge, Massachusetts, and was co-founded in 1997 by Joseph Jacobson, a professor in the MIT Media Lab. Two years later, E Ink partnered with Philips to develop and...
, flexible EPLaREPLaRElectronics on Plastic by Laser Release is a method for manufacturing flexible electrophoretic displays using conventional AM-LCD manufacturing equipment avoiding the need to build new factories... - SamsungSamsungThe Samsung Group is a South Korean multinational conglomerate corporation headquartered in Samsung Town, Seoul, South Korea...
- Seiko EpsonSeiko Epson, commonly known as Epson, is a Japanese technology company and one of the world's largest manufacturers of computer printers, information and imaging related equipment...
See also
- E-bookE-bookAn electronic book is a book-length publication in digital form, consisting of text, images, or both, and produced on, published through, and readable on computers or other electronic devices. Sometimes the equivalent of a conventional printed book, e-books can also be born digital...
- E InkE InkE Ink is a specific proprietary type of electronic paper manufactured by E Ink Corporation, founded in 1997 based on research started at the MIT Media Lab...
- Electrofluidic
- Flexible electronicsFlexible electronicsFlexible electronics, also known as flex circuits, is a technology for assembling electronic circuits by mounting electronic devices on flexible plastic substrates, such as polyimide, PEEK or transparent conductive polyester film. Additionally, flex circuits can be screen printed silver circuits on...
- List of e-book readers
- Display examplesDisplay examplesOver the years, a variety of display devices and technologies have been used in order to display electronic data in a way that's legible to humans.-Early history:...
Further reading
- Electric paper, New Scientist, 2003
- E-paper may offer video images, New Scientist, 2003
- Paper comes alive New Scientist, 2003
- Most flexible electronic paper yet revealed, New Scientist, 2004
- Roll-up digital displays move closer to market New Scientist, 2005
- Seiko Epson develops ultra-dense e-paper display Electronista, 11-2007
- Unidym and Samsung Electronics demonstrate the world's first colour carbon-nanotube-based electrophoretic display Unidym Press Room, 10-2008
External links
- Epaper Central, electronic paper news, information, analysis
- E-paper display market reaches $1.17 billion in 2014
- Electronic Paper: Merging between Traditional Publishing and E-Publishing
- Wired article on E Ink-Philips partnership, and background, retrieved 2007-08-26
- MIT ePaper Project
- Xerox PARC epaper project
- Gamma Dynamics: Commercializing a New Pigment-Based Electrowetting Display
- Office of Tomorrow
- The Future of Electronic Paper, Past, present and future of e-paper, includes interview with Nick Sheridon, father of e-paper at Xerox
- Fujitsu Develops World's First Film Substrate-based Bendable Color Electronic Paper featuring Image Memory Function