Desired future improvements for this technology include bistability, cheaper materials and implementation with TFT arrays. Other technologies[ edit ] Other research efforts into e-paper have involved using organic transistors embedded into flexible substrates ,   including attempts to build them into conventional paper.
The array of pixels is divided into triads , 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. Disadvantages[ edit ] Electronic paper technologies have a very low refresh rate compared to other low-power display technologies, such as LCDs. This prevents producers from implementing sophisticated interactive applications using fast-moving menus, mouse pointers or scrolling like those common on standard 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.
An e-ink screen showing the "ghost" of a prior image 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 screen burn-in, 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. The Ectaco Jetbook Color was released in as the first colored e-ink e-reader, which used E Ink's Triton display technology.
The JetBook Color costs roughly nine times more than other popular e-readers such as the Amazon Kindle. Please update this article to reflect recent events or newly available information. October An e-paper display on a watch refreshes to remove ghosts. 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.
The resulting backplanes certainly live up to the definition of e-paper, and although commercially they are in the more distant future the technology needs to be considered within the scope of this report. Electrochromic frontplane Electrochromic materials are materials that change colour upon application of an electrical potential.
Electrochromic systems have been used successfully in the past in mirrors and windows for anti-glare and anti-reflective applications. However, other potential applications have yet to reach the market, largely due to the limitations of existing electrochromic materials. To date, most commercial electrochromic technologies have used solution based systems, which rely on organic electrochromic species dissolved in the electrolyte compartment of an electrochemical cell which has at least one transparent electrode.
The most commonly used electrochromophores, salts of 4,4'-bipyridines, also called viologens, are synthetically tunable which allows for different colours, and have intrinsically high extinction coefficients, yielding excellent colouration intensities. The switching speed depends on the diffusion of these and other redox active species in the electrolyte to the electrodes and is typically in the order of seconds.
Because the redox active species are dissolved in an electrolyte these mobile molecules will diffuse to both electrodes once an appropriate electrical potential has been applied to the circuit. Once the potential has been removed, the charged species mix, transfer their charges, and the colour dissipates from the system.
Therefore there is no open circuit memory in these devices and power must be applied continuously to maintain colouration. OLED frontplane The term OLED stands for Organic Light Emitting Diode and as this implies the technology is based upon the use of special organic compounds, light emitting polymers, that emit light when electricity is passed through them.
The technology was developed back in the s at the Cavendish laboratory at the University of Cambridge. The technology of Light Emitting Polymers or LEPs allows the construction of full colour displays that are much cheaper to make and run than CRTs because the active material is plastic.
An LEP display consists solely of the polymer material manufactured on a substrate of glass or plastic and does not require additional elements such as the backlights, filters and polarizers typical of LCDs. LEP is a platform technology that will scale from tiny devices literally millimeters in dimension to large high-definition devices that could be up to a couple of metres.
The only real drawback to OLED technology for use in portable battery powered devices is that because it is an emissive technology it uses a lot more power than most reflective technology displays, neither does it have the power saving feature of bistability shown by many other technologies covered in this report.
It is also limited in its appeal to devices designed for use in dim ambient light; since it is almost impossible to see what is displayed on an OLED display when viewed in bright sunlight. Whilst in theory OLED displays can be constructed on thin flexible plastic substrates, all of today's commercial OLED displays use rigid glass substrates. This is partly because it has been easier to construct TFT active matrix backplanes on glass substrates using standard LCD manufacturing equipment, but it is also because of the fact that the polymers used in OLEDS are quickly destroyed by exposure to air and moisture.
This means that means that they need to be very well encapsulated to protect them, and to date a reliable encapsulation technique for flexible substrate OLED displays has not been developed to a commercial stage.
However, research into ways of solving this problem is ongoing and researchers have expressed the belief that it will probably be solved within the next year. In the meantime the only reliable way of encapsulating OLED displays is with a rigid substrate like glass.
Electrowetting frontplane The phenomenon of electrowetting offers the possibility of creating flexible displays with a far faster refresh rate than is possible with electrophoretic displays, making such displays suitable for displaying video content.
The colour displays will also be much brighter than conventional LCD displays since they will not rely upon filters. This technology could be regarded as very similar in principle to electrophoretic display technology, but without several of its drawbacks.
It is still in the development stage, but should be in commercial production by Each pixel of the display consists of a micro cell that contains a drop of coloured, oily ink suspended in an aqueous medium. At the bottom of the cell is a reflective white background that has been coated first with a transparent material that conducts electricity - permitting electrical control of the pixel colour - and then with a transparent film of a water-repellent plastic.
Normally the ink droplet will spread across the entire pixel thus obliterating the white background. However, if a voltage is applied, the oil droplet retracts, much like a bead of water in a Teflon pan, thereby exposing the white area below.
If the microcell is small enough, these white and ink covered regions are not individually visible. Instead, the effect is that the pixel acquires just an average brightness level, so that when the droplet is fully spread, the pixel looks dark, and when it retracts, the pixel looks much lighter. A very significant feature of this technology is the fact that the larger the applied voltage, the more the ink droplet retracts.
This means that the ink capable of a continuous grey scale, not just of the bichromal contrast found in most electrophoretic technologies. This feature will remove much of the "jaggies" or roughness due to digitisation, and will produce images that look very smooth. The key to the system's success is its switching voltage. It is low enough that controlling the electronic ink requires only a small power source.
Hopefully this can be improved through software updates, or a faster processor on future versions of the tablet, so that I can keep on printing like a grade schooler. Advertisement That 1GHz processor which is slower than the one the Kindle Oasis uses and just Mb of RAM also results in boot-up times of about 15 seconds, the occasional sluggishness when loading larger files, and some unfortunately long waits when zooming in and out of a page full of notes and illustrations. There are frustrating gaps in usability.
Advertisement As wonderful as the tablet is to write on, it lacks handwriting recognition. These might seem like small problems, but they add up over time. Advertisement Other software issues are harder to see.
The palm-rejection functionality is rock solid, ensuring you never make accidental screen presses while holding the tablet and writing, but it comes at the cost of not being able to flip through documents using finger swipes or taps. A: No technology is sufficiently paper-like, yet. By this, I mean a display medium that is thin, flexible, capable of storing readable images without power consumption, highly readable in ambient light, and has good resolution, high whiteness, and good contrast — and is pretty cheap.
A big part of this equation is the addressing electronics. Organic thin film transistors, or TFTs, will provide flexible addressing at a low cost, and other technologies show promise, but none of these are quite ready. Q: Are these problems currently being addressed by the industry? A: More than a dozen companies have announced work on active e-paper programs, and there are a number of start-ups.
As I mentioned, the low cost and flexible electronic-addressing capability of organic TFT technology is important and is being intensively developed by a number of organizations. Still, I have not yet seen the ideal e-paper media solution.
Q: Are you still working on the development of e-paper? A: Xerox closed its Gyricon operation in December for financial reasons. I was director of research. I am now working independently and doing some consulting. And, yes, I am working to invent the perfect e-paper medium. Q: When do you think we will see widespread use of e-paper? A: I think the revolution will evolve, first as handheld displays of high contrast that are readable in direct sunlight —probably in the next year or two—followed by low power-consuming book readers available in Japan, and more widely as intellectual-property rights issues are sorted out ; and over the next five years, electronic signs and billboards.
The pocket document reader will take a little longer. Q: How do you see the future of e-paper? Credit: Xerox. A: I like to tell people that the holy grail of e-paper will be embodied as a cylindrical tube, about 1 centimeter in diameter and 15 to 20 centimeters long, that a person can comfortably carry in his or her pocket.
The tube will contain a tightly rolled sheet of e-paper that can be spooled out of a slit in the tube as a flat sheet, for reading, and stored again at the touch of a button. Information will be downloaded—there will be simple user interface—from an overhead satellite, a cell phone network, or an internal memory chip.
This document reader will be used for e-mail, the Internet, books downloaded from a global digital library that is currently under construction, technical manuals, newspapers perhaps in larger format , magazines, and so forth, anywhere on the planet.
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. Like other forms of e-paper, it requires very little power.
There's no mention of customers who are already lined up, so it may take a while before there are shipping devices using JustWrite displays.
A: There was a eureka moment when the need for e-paper crystallized in my mind and I realized—or thought I did—the magnitude of the challenge. From the second generation onwards all e-paper displays will at least be bendable, these displays are entering the manufacturing phase now.
Reversing the voltage has the opposite effect. Two companies, HP and Fujitsu, have demonstrated actual devices. So how can a tablet with limited applications and a grayscale display be worth that price? Both problems are the subject of considerable research effort and look set to be overcome in the not too distant future.
Electrophoretic frontplane consists of millions of tiny microcapsules, each approximately microns in diameter—about as wide as a human hair.
Other products to be marketed have more substantial applications. Citizen E-ink clock Credit: Citizen Potential applications of e-paper technology is staggering. Do I wish it had a backlight of some sort so it was usable in a darkened theater during a press conference? Its initial product, introduced in May , was an in-store display sign for J.
He thought it would be ready for the market around , if he could just lick a few practical problems.
The colour displays will also be much brighter than conventional LCD displays since they will not rely upon filters. It's easy to see a wide range of uses, though.
The JetBook Color costs roughly nine times more than other popular e-readers such as the Amazon Kindle. Another area where highly flexible displays will find an application is in wearable data display systems for military and other use. In the more distant future we may see a number of highly flexible e-paper displays bound together to form the electronic equivalent of a book, with display control and data storage electronics in the spine. Although some people, especially younger computer users, are happy to read from screen for long periods, most users find that the above reasons limit the time that they can comfortably spend reading off screen. The key cause of this demise, attendees were told, will be the newly developed e-book. Both problems are the subject of considerable research effort and look set to be overcome in the not too distant future.
With cholesteric LCDs the liquid crystal molecules form spirals, which means that incoming light is reflected or transmitted depending on the spiral's axial direction, which changes in line with the height and length of voltage pulses. And, yes, I am working to invent the perfect e-paper medium. Introduction It is a term that has been used rather loosely for a long time, but broadly speaking it is a display technology that has all the attributes of paper but can be written to and erased electronically.
By IBM was also in the fray, and Philips was rumored to be sniffing around the e-paper market. Most e-paper technologies are well able to deliver resolutions up to ppi and many have already been demonstrated at ppi. In some sense, Sheridon was too early. If an electric field comes near the spheres, it attracts or repels their black halves, causing the spheres to rotate. After the reader selects the Origin with the stylus, the text swims noiselessly onto the empty pages of the volume. The technology is also bendable, works with virtually any size and shape, and needs just a basic stylus as well as some basic electronics -- it shouldn't carry a significant premium.
Yet another development, nearly lost among those important breakthroughs, was invented in by PARC employee Nicholas K. Plasmonic electronic display[ edit ] Plasmonic nanostructures with conductive polymers have also been suggested as one kind of electronic paper. Electrofluidic displays place an aqueous pigment dispersion inside a tiny reservoir.