E-paper technology was born in the 1970s, but the real boom is now 35 years later.

Electronic paper was originally invented to replace the massive consumption of traditional paper. Today, the impact of the emergence of electronic paper on the traditional paper publishing industry is gradually reflected. At present, there are more than 20 kinds of electronic paper carriers in the world, 8 kinds of new electronic paper carriers were born in 2007 alone, and the number will be nearly 40 in 2008. Table 1 shows the statistics of the development of e-paper market in recent years. The essence of electronic paper is a kind of flexible display first. Behind its thin and soft characteristics, the emergence of the traditional flat panel displayShow the industry more thorough impact

Market size of e-paper, 2004-2010 (Source: Fujifilm chimera)

Introduction to Electronic Paper

The carrier of electronic paper is a special thin film, through the film "coated" on a layer of charged material (electronic ink), according to the different contents of the background control, through the corresponding display combination to achieve the purpose of content display, the core of the electronic paper is a generalized IC, the whole reader can be regarded as a thin embedded remote control display board. In e-ink, many black and white particles with positive and negative charges are sealed in microcapsules. Depending on the electric field applied, different concentrations are generated on the surface of the monitor, presenting a black or white effect. The most commercially available non-liquid crystal e-paper technology is E-Ink (electrophoretic e-paper). It has many advantages, the most important is that the content can be rewritten, you can arbitrarily update the text or image, so as to achieve a large number of content unified platform browsing. At the same time, it is very suitable for naked eye reading, because the contrast is high, so the text and image are clear, and no matter from which direction there is no change, reading comfortable and easy. Power saving is also a major feature of e-paper. After text is refreshed, it will stay on the screen for a long time, and the battery can be removed while reading. In other words, you don't use power when you're reading, you only use power when you're turning pages and refreshing, so you get a long battery life. Because of the light weight of the film, the electronic paper can also be moderately folded and curled, light weight, easy to carry.

Another form of e-paper is a portable thin film display board, that is, "paper" flexible liquid crystal display. This way is to use the properties of the liquid crystal whose molecular arrangement is changed after voltage is applied, and express the contrast by adjusting the transmittance and changing the direction of light. The idea of making e-paper liquid crystal display is as follows: The liquid crystal plate can be separated from the device that writes the image to make it thin and lightweight, and it can be curled into a paper-like object. Writing can be achieved by applying light, heat, surface charge and other methods. Relative to other non-liquid crystal technology to achieve such products as electronic paper on the cost of a slight disadvantage. Its main feature is that the visual reading condition is relatively good, even if the gaze for a long time will not make the eyes feel tired, can be adjusted on the surface of the light sense, processing. Equipped with CPU and semiconductor memory, the device is easy to carry, simple to use, just the button can read electronic documents or electronic books. And expect to hook up with the network, do random access. Electronic notebook made of electronic paper cluster can be used for digital data access, and can be used to store information with the help of records, because electronic paper has such functions and utilization value as above, so it is easy to be accepted by users.

Characteristics of electronic paper

Energy saving: Electronic paper is bistable, only when driving (writing) has a minimal power consumption, display static images do not consume power, do not need backlight

Paper-like optical properties: reflective, wide viewing Angle, paper-like reading experience, no flicker, eyes are not easy to fatigue, can be read outdoors or in the sun

Ultra-thin, flexible (mechanical paper-like) : electrophoresis shows that the thickness of the e-paper film is close to that of paper. The backboard of flexible substrate can be selected to make ultra-thin or flexible display screen, which has good portability and anti-impact ability

How electronic paper works

At present, the most representative electronic paper display technology mainly includes: electrophoresis display technology (EPD); Cholesterol liquid Crystal Display technology (Ch-LCD);

Bistable directional column liquid crystal technology (Bi-TN LCD); Electrowetting display technology (EWD); Electric fluid display technology (EFD); Interference Modulation Technology (iMoD) (Qualcomm mirasol®). Electrophoretic display technology (EPD) is the most representative, with mature technology, high performance, mature mass production, low cost, and a market share of more than 90%.

E-paper consists of e-ink and two substrates: the first part is e-ink, sometimes called the "front plane"; The other is to make electronic ink to generate text and image required by the combination of electronic equipment, including the control part and the display part, known as the "backplane". The back plate is coated with e-ink made up of countless tiny transparent particles half the diameter of a human hair. Electronic ink is a special material processed into a thin film. It is used in combination with electronic display equipment. It is a comprehensive application of chemistry, physics and electronic technology. E Ink is made up of millions of tiny microcapsules, the diameter of a human hair. Each microcapsule contains positively charged white particles and negatively charged black particles suspended in a clean liquid. As shown in Figure 1, the top of the e-ink film is a transparent material, which is used as an electrical extreme; The microcapsule is sandwiched between the other e-ink electrode at the bottom. Microcapsules are subjected to a negative electric field

When, the white particle is positively charged and moves to the top of the microcapsule, and the corresponding position is shown as white. The black particles are negatively charged and reach the bottom of the microcapsule under the action of electric field force, and the user cannot see the black. If the electric field is acting in the opposite direction, the display effect is also reversed, that is, black is displayed and white is hidden. It can be seen that simply changing the direction of the electric field can switch between the black display and the white display. The white part corresponds to the uninked part of the paper, while the black part corresponds to the printed text on the paper.。 

When applied to paper, cloth or other flat objects, a properly applied electric shock can cause hundreds of millions of particles to change color, constantly changing the patterns and words that appear, depending on what you want them to do. By adjusting the color of the dye and the tiny particles inside the particles, E ink can display colors and patterns. The method uses microcapsules that can change the state of black and white under voltage to achieve image display. Charged white titanium oxide particles and black toner particles in the microcapsule move up and down under a voltage to create a black and white image. Its characteristics are ideal in contrast, brightness vision, low power consumption, light weight and easy to make it thin, free shape, etc. In addition, some products are the use of charged electrophoresis phenomenon, by increasing the density of the body to improve the contrast between black and white.

In fact, the company is actively developing the integration of e-paper and computer, and has successfully produced a PDA with e-paper embedded in the display, and e-paper that can be connected to mobile phones. Future e-paper will further enrich the above mentioned display functions, at the same time, will also expand the scope of application, improve the ease of use, such as the realization of multiple data display at the same time or handwritten input like paper. The future development of this field will arouse people's wide concern.

In addition, creative products such as a large outdoor screen advertising billboard, a thermostat equipped with an e-paper display, mobile phones, and watches were also displayed on the site, heralding the future development of e-ink technology. .