E Ink (electronic ink) is a popular type of electronic paper (e-paper) display technology, characterized by high visibility and contrast, a wide viewing angle and low power requirements. The technology has been commercialized by the E Ink Corporation, which was co-founded in 1997 by MIT undergraduates J.D. Albert & Barrett Comiskey, MIT Media Lab professor Joseph Jacobson, Jerome Rubin and Russ Wilcox.
It is currently available commercially in grayscale and color and is commonly used in mobile devices such as e-readers, and, to a lesser extent, digital signage, smartwatches, mobile phones, electronic shelf labels and architecture panels.
The notion of a low-power paper-like display had existed since the 1970s, originally conceived by researchers at Xerox PARC, but had never been realized. While a post-doctoral student at Stanford University, physicist Joseph Jacobson envisioned a multi-page book with content that could be changed at the push of a button and required little power to use.
Neil Gershenfeld brought in Jacobson to the MIT Media Lab in 1995 after hearing his ideas for an electronic book. Jacobson, in turn, recruited MIT undergrads Barrett Comiskey, a math major, and J.D. Albert, a mechanical engineering major, to create the display technology required to realize his vision.
The initial approach was to create tiny spheres which were half white and half black, and which, depending on the electric charge, would rotate such that the white side or the black side would be visible on the display. Albert and Comiskey were told this approach was impossible by most experienced chemists and materials scientists and they had trouble creating these perfectly half-white, half-black spheres, and during his experiments, Albert accidentally created some all-white spheres.
Comiskey experimented with charging and encapsulating those all-white particles in microcapsules mixed in with a dark dye. The result was a system of microcapsules which could be applied to a surface and then could be charged independently to create black and white images. A first patent was filed for this microencapsulated electrophoretic display by MIT in October 1996.
The scientific paper was featured on the cover of peer-reviewed journal Nature, unusual for work done by undergraduate students. The advantage of the microencapsulated electrophoretic display, and its potential for satisfying the practical requirements of electronic paper are summarized in the abstract of the Nature paper:
It has for many years been an ambition of researchers in display media to create a flexible low-cost system that is the electronic analogue of paper. In this context, microparticle-based displays have long intrigued researchers. Switchable contrast in such displays is achieved by the electromigration of highly scattering or absorbing microparticles (in the size range 0.1–5 μm), quite distinct from the molecular-scale properties that govern the behaviour of the more familiar liquid-crystal displays. Micro-particle-based displays possess intrinsic bistability, exhibit extremely low power d.c. field addressing and have demonstrated high contrast and reflectivity. These features, combined with a near-lambertian viewing characteristic, result in an "ink on paper" look. But such displays have to date suffered from short lifetimes and difficulty in manufacture. Here we report the synthesis of an electrophoretic ink based on the microencapsulation of an electrophoretic dispersion. The use of a microencapsulated electrophoretic medium solves the lifetime issues and permits the fabrication of a bistable electronic display solely by means of printing. This system may satisfy the practical requirements of electronic paper.
A second patent was filed on the microencapsulated electrophoretic display by MIT in March 1997.
Subsequently, Albert, Comiskey and Jacobson along with Russ Wilcox and Jerome Rubin founded E Ink Corporation in 1997, two months prior to Albert and Comiskey's graduation from MIT.
At the E Ink Corporation, Comiskey led the development effort of E Ink's first generation of electronic ink, while Albert developed the manufacturing methods used to make electronic ink displays in high volumes. Wilcox played a variety of business roles and served as CEO from 2004-2009.
On June 1, 2009, E Ink Corp. announced an agreement to be purchased by one of its primary business partners, Prime View Int'l Co. Ltd (元太科技工業), for US$215 million. However, from June to December 2009, the purchase price was re-negotiated and E Ink was finally officially acquired on Dec. 24, 2009 for $450 million. The purchase by this Taiwanese company has put the production of the E Ink e-paper display on a larger scale than before, as Prime View also owns BOE Hydis Technology Co. Ltd (京东方海帝士科技) and maintains a strategic partner relationship with Chi Mei Optoelectronics Corp., which is now Chimei InnoLux Corporation (奇美電子), part of the Hon Hai-Foxconn Group (鴻海富士康集團). Foxconn is the sole ODM partner for Prime View's Netronix Inc. (振曜科技), the supplier of E Ink panel e-readers for rebranding - the end-user products may appear with any of several brands, e.g., Bookeen, COOL-ER, PocketBook, etc.
E Ink's transformative impact on the publishing and reading industry has been recognized by several awards, including:
The Motorola F3 was the first mobile phone to employ E Ink technology into its display, taking advantage of the material's ultra-low power consumption. In addition, the Samsung Alias 2 uses this technology on the keypad, to allow orientation to change. The October 2008 limited edition North American issue of Esquire was the first magazine cover to integrate E Ink and featured flashing text. The cover was manufactured in Shanghai, China, was shipped refrigerated to the United States for binding and was powered by a nominal 90-day integrated battery supply.
Applications using E Ink have since expanded, enabling smart designs for digital signage, electronic shelf labels, wearables and architecture. Advantages of E Ink include low power usage, flexibility, durability and ruggedness and better readability under direct sunlight. Given these properties, E Ink displays can be used for a broad range of surfaces and solutions.
In July 2015, the Australian Road and Maritime Services installed road traffic signs using E Ink in Sydney, Australia. The installed e-paper traffic signs represent the first use of E Ink in traffic signage. Transport for London trialed E Ink displays at bus stops which offered timetables, route maps and real-time travel information to better update travel information. Select Whole Foods 365 stores have employed E Ink-powered electronic shelf labels, which can be adjusted and updated remotely and can include additional information such as whether a product is gluten-free. E Ink Prism was announced in January 2015 at International CES and is the internal name for E Ink’s bistable ink technology in a film that can dynamically change colors, patterns and designs with architectural products.
Each version/model of E Ink is marketed under different brand names, as detailed below.
E Ink Vizplex is the retroactive name used to refer to the first generation of the E Ink displays. Vizplex was the internal name of E Ink's display technologies, which was announced in May 2007. E Ink originally used the term "Vizplex" as an umbrella term that included multiple generations of E Ink display technologies. For example, E Ink Pearl and E Ink Triton used the text "E Ink Vizplex" at the bottom of startup screens for those displays. However, as more generations were released, "Vizplex" became more often used to refer to specifically the first generation of the E Ink product line, in order to have a designation for the first generation to distinguish it from future generations.
E Ink Pearl, announced in July 2010, is the second generation of E Ink Vizplex displays, a higher-contrast screen built with E Ink Pearl imaging film. The updated Amazon Kindle DX was the first device announced to use the screen, and the Kindle Keyboard, Kindle 4, and Kindle Touch also incorporate the Pearl display. Amazon still uses this display technology in the Kindle (all generations, minus the Paperwhite, Voyage, and Oasis series). Sony has also included this technology into its latest release of the Sony Reader Touch edition. This display is also used in the Nook Simple Touch, Kobo eReader Touch, Kobo Glo, Onyx Boox M90, X61S and Pocketbook Touch.
E Ink Mobius (also known as E Ink Flex) is a modification of E Ink Pearl. It does not have one of the main disadvantages of the first two models of E Ink displays: a substrate made of very thin glass. E Ink Vizplex and E Ink Pearl have fragile screens which can be broken easily. The substrate of E Ink Mobius is made of flexible plastic, so it can resist small impacts and some flexing. Nearly A4-sized E ink Mobius devices make up the most expensive e-readers. These include Sony Digital Paper DPT-S1, Pocketbook CAD Reader Flex and Onyx Boox MAX.
E Ink Triton, announced in November 2010, is the third generation of E Ink Vizplex displays: a color display that is easy to read in high light. The Triton is able to display 16 shades of gray, and 4,096 colors. E Ink Triton is used in commercially available products such as the Hanvon color e-reader, JetBook Color made by ectaco and PocketBook Color Lux made by PocketBook.
E Ink Carta, announced in January 2013 at International CES, is the fourth generation of E Ink displays and features 768 by 1024 resolution on 6-inch displays, with 212 ppi pixel density. Named Carta, it is used in the Kindle Paperwhite 1st (2012) and 2nd (2013) generations and the Pocketbook Touch Lux 3 (2015).
E Ink Carta HD features a 1080 by 1440 resolution on a 6" screen with 300 ppi. It is used in many eReaders including the Kindle Voyage (2014), Tolino Vision (2014), Kobo Aura H2O (2014), Kindle Paperwhite 3rd and 4th generation (2015 and 2018), Kobo Glo HD (2015), Nook Glowlight Plus (2015), Cybook Muse Frontlight, Kindle Oasis (2016), PocketBook Touch HD(2016), PocketBook Touch HD 2 (2017), and the Kobo Clara HD (2018).
E Ink Carta and Carta HD displays support Regal waveform technology, which reduces the need for page refreshes.
E ink Spectra is a three pigment display. The display uses microcups, each of which contains three pigments. It is available for retail and electronic shelf tag labels. It is currently produced with black, white and red or black, white and yellow pigments.
Advanced Color ePaper (ACeP) was announced at SID Display Week in May 2016. The display contains four pigments in each microcapsule or microcup thereby eliminating the need for a color filter overlay. The pigments used are cyan, magenta, yellow and white, enabling display of a full color gamut and up to 32,000 colors. It will be initially targeted at the in-store signage market, with 20-inch displays with a resolution of 1600 by 2500 pixels at 150 ppi. An ACeP display will have a 2-second refresh rate. E Ink expects commercial production within two years of 2016.
A comparison of a selection of E Ink displays as of June 2017.
|Resolution(HxV)||240 x 240||256 x 256||296 x 128||600 x 360||800 x 480||960 x 540||960 x 540||1448 x 1072||1440 x 1080||1872 x 1404||1872 x 1404||2200 x 1650||2560 x 1440||2880 × 2160|
|Active Area(mm)||27.96 x 27.96||23.30 x 23.30||14.46 x 33.45||45.54 x 75.90||56.16 x 93.60||58.32 x 103.68||64.53 x 114.24||90.60 x 122.40||103.68 x 138.24||118.64 x 158.18||157.25 x 209.66||270.60 x 202.95||691.20 x 388.80||642.6 x 856.8|
|Outline Dimensions(mm)||34.60 x 31.80||27.10 x 28.40||18.30 x 42.70||51.54 x 86.50||62.40 x 106.40||62.1 x 115.2||69.23 x 124.59||101.80 x 138.40||119.70 x 158.50||127.60 x 173.80||165.80 x 227.70||287.00 x 215.50||697.20 x 402.80||650.0 × 872.5|
|E Ink Film||Carta 1.2||Thin Pearl||Pearl||Pearl||Pearl||Carta 1.2||Carta 1.2||Carta 1.2||Carta 1.2||Carta 1.2||Carta 1.2||Carta 1.2||Pearl||Pearl|
|Refresh Time||800ms||3.2 sec||800ms||450ms||450ms||480ms||480ms||450ms||450ms||450ms||450ms||450ms||980ms||-|
|Surface Treatment||Hard Coat||Hard Coat||Hard Coat||Hard Coat||Hard Coat||Hard Coat||Hard Coat||Anti-glare Treatment||Anti-glare Treatment||Hard Coat||Anti-glare Treatment||Anti-glare Treatment||Hard Coat||Hard Coat|
Electronic paper and e-paper, also sometimes electronic ink or e-ink, are display devices that mimic the appearance of ordinary ink on paper. Unlike conventional backlit flat panel displays that emit light, electronic paper displays reflect 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 (2008) developed displays are slightly better. An ideal e-paper display can be read in direct sunlight without the image appearing to fade.
Many electronic paper technologies hold static text and images indefinitely without electricity. Flexible electronic paper uses plastic substrates and plastic electronics for the display backplane. There is ongoing competition among manufacturers to provide full-color ability.
Applications of electronic visual displays include electronic pricing labels in retail shops and digital signage, time tables at bus stations, electronic billboards, smartphone displays, and e-readers able to display digital versions of books and magazines.