Innovative electronic paper

Since the 20th century, the demand for paper has continued to grow. People have become accustomed to reading traditional papers, and even if they have computers, they prefer to print. The New York Times once published an article titled "The Paperless Office Wants to Print Documents to Be Insured," which points out the fact that after the automation of the office, the use of paper by the world has gone up. Canada, the world’s largest exporter of office paper, has doubled its paper exports in the past 15 years. According to Emerson, president of Tembec Inc., an important paper exporter in Canada, office consumption will increase by at least 50% over the next 10-15 years.

Why not "paper" is not available? In fact, computers and other devices are only suitable for complex operations and word processing, but they are inconvenient to read. In addition to the consideration of reading comfort, according to research, in fact, the memory effect of paper reading is 30% higher than that of screen reading, and paper can always be annotated, and the stability of computer equipment still needs to be strengthened, in order to prevent crashes. Data is destroyed due to power failure or human negligence. Many people are accustomed to printing. Therefore, even in today's ever-changing digital technology, the use of paper has not only declined, but has increased year by year.

In order to solve the problem of e-reader development stagnation, electronic ink is considered as the best solution. E-book reader is a kind of portable electronic display. Although it has many advantages that paper books don't have, the books in user concept should have soft paper. Otherwise, they think e-book reader is just a steel monster. . Therefore, manufacturers have to look at the development of electronic ink, electronic paper.

In addition to e-books, electronic monitors are also commonly used in displays. Existing displays, such as LCDs, LEDs, CRTs, etc., are inaccessible because of insufficient brightness, or they cannot be seen when the angle is changed, and they are cumbersome and unreliable, and they also consume electricity. Looking at the PDA's small-screen display for a long time, the eyes get tired and the burden on longer documents is greater. Electronic inks improve the lack of general displays and have advantages in terms of legibility, portability, and ergonomics.

The manufacture of traditional paper requires the consumption of large amounts of natural resources, the long printing cycle, the slow delivery speed, and the irreplaceability of the loaded information. This is obviously lagging behind the rapid development of science; however, traditional paper has no viewing angle restriction when reading, and reading and saving information is not Need to consume other energy, light, soft, easy to carry. E-paper absorbs these advantages, plus the reusability of electronic displays, so that the graphics printed on paper can also be changed at any time, which is the direction of development of electronic paper.

After more than 20 years of research, the electronic paper technology has made breakthrough progress. In 2000, the American electronic ink company and Lucent Technologies Inc. officially announced electronic ink technology that allowed paper and ink to enter a revolutionary era.

Electronic paper, also known as digital paper, combines the length of paper and electronic display boards. Today, electronic paper has been defined as thermal rewrite media. The main features of this e-paper are:

(1) Content rewritable: Any text or image can be overwritten.

(2) Reading with the naked eye: Scarcely stimulates the naked eye from the display plane.

(3) Portability: Since the film is light, it can be carried around.

(4) Hold the image: The display can be held for a long time when there is no power.

At present, electronic paper generally has two forms: The first form is just like the paper that is used today. As long as the paper is supplied to the printer, it erases the entire contents first, and then writes new information. The user does not feel it at all. The image has been erased; the second form is a portable thin-film display board with a built-in CPU and a semiconductor memory. Several electronic files and books can be read by pressing a button. access.

Technology and Products

At present, there are a number of companies that research and develop electronic paper. Although their actual technologies are different, the principle is basically the same. Among them is the American electronic ink company. The following describes the company's technology as an example.

Microcapsule electrophoresis

The American electronic ink company uses the "microcapsule electrophoresis" technology - charged particles suspended in a liquid move under the electric field. This technology was developed by the Massachusetts Institute of Technology and Electronic Ink Corporation. The basic principle is to put blue and other dark dye liquids and light-colored charged microparticles in cell-sized transparent microcapsules, and attach the microcapsules to a film with a transparent electrode with an adhesive. The electric field was adjusted to electrophorese the light-colored particles to display the images formed by white and cyan. Titanium oxide particles are used in the white particles, and they are stably dispersed in the blue insulating liquid. This microcapsule is coated with silicone resin as a binder on a film with an ITO electrode, and then a negative charge pattern is applied to the surface by ion flow, and the white particles are moved to the lower part of the microcapsules, so that the surface is drawn Blue image. If the positive charge is fully applied, the white particles move to the upper part of the microcapsules, and the surface becomes white, and the image is erased. If a transparent microcapsule containing color particles is used, the microcapsule floats in the liquid medium to achieve the effect of color change. The manufacturing process uses a standard technique of commercial microencapsulation, and the entire thickness can reach 0.2 mm.

In theory, as long as the method of screen printing is used, electronic ink can be printed on the surface of any substrate, such as glass, plastic, fiber, or even paper, that is, any material can be used as electronic paper. The e-papers that are currently seen are all made of plastic. The plates are thin and can be curled. Since the electronic paper forms an image through the electronic ink with its own color, the graphic can be manifested using the principle of reflected light, and consumes very little power. If the paper does not change the picture, you can use electricity completely.

2. Technical advantages

Electronic paper must be the major trend in the future development of paper or display. Understanding its technical advantages, it can find more application value.

As electronic papers are now seen, they are all coated with pigments that can be affected by the influence of charge on the two layers of ultra-thin plastic sheets. The offset film is very light and thin, and can be curled, folded, soft and flexible. The electronic paper is more suitable for reading than any display device because it is illuminated with reflected light and the displayed color is the same as the real ink written on the paper, so the brightness can reach 3 to 6 times that of the reflective color LCD, which is the same as the paper. . The black and white particles in the ball are also bright and dark, and when reading small texts, you can reduce eye fatigue. At the same time, the characteristics of the electronic ink make the text displayed thereon smoother, and can be read from any angle, and it is not necessary to adjust the angle like the LCD to find the best reading state.

Power saving is another major advantage of electronic paper. Electronic paper only needs to be energized when inputting data. After completion, it will be in a fixed state, consumes little power, and does not need to turn on the backlight when it is normally used. Therefore, the standard power consumption of electronic paper is less than one thousandth of that of LCD displays. Electronic paper can be recycled and used up to 100 times. It can also be painted on a large surface or even a wall, which is beyond other display technologies. This technology will soon be used to improve the screen display quality of mobile phones, PDAs, E-mails or e-reading devices.

3. The development of electronic paper

The development of electronic paper has been intermittent for the past 20 years and has only recently been rapid. At present, the main producer is American Electronic Ink Company.

In 1995, when Jacobson, a director of American Electronic Ink Corporation, was a postdoctoral researcher in the Department of Physics at Stanford University in the US, he proposed a conception of the book—each page of the book could be reprinted using electronic technology and stored on the back of the book. Silicon memory. The invention of electronic ink came from this. In 1997, Jacobson and three students joined forces to open an electronic ink company in Cambridge, Massachusetts. The company immediately attracted venture capital companies, corporate investors and other funds, including research and development grants from Motorola, Hearst Co., and the U.S. Department of Defense’s Higher Research Projects Agency. In 1999, electronic ink technology had its first products. It was a hard billboard with an immediacy size of 1.2 to 1.8 meters.

So far, electronic ink technology has gradually matured, and now there are many products that use electronic ink technology. Most notable is the Sony e-book reader LIBRI'e, which was launched in March 2004. This first-generation Philips monitor uses innovative electronic ink technology from American Electronic Ink. Philips integrated the films on an active backplane and added electronic drive components to develop and develop display solutions with Sony.

LIBRI'e has the same volume and design as a paperback book. Its monitor has no background light, the font color is grayish, the text does not darken with the swing of the hand, can also be used normally in the insufficient light place. Although the resolution of the LIBRI'e reader is only 800 dpi x 600 dpi, the clarity of its black and white fonts is sufficient to outperform any LCD screens, making them look like newspapers. Power consumption is required only when the graphics change, so four AAA alkaline batteries can read more than 10,000 pages. At present, it is only sold in the Japanese market, priced at 380 US dollars.

The LIBRI'e reader is connected to the computer through a USB interface. Some media publishers have jointly launched an appropriate book download service. The LIBRI'e reader is currently equipped with 10MB of memory and can hold approximately 20 pages of e-books. However, LIBRI'e readers do not support copying books to other electronic devices, and the downloaded books will expire in 2 months. Currently, LIBRI'e series e-books sell for only US$3 each.

The LIBRI'e Reader is a major milestone for electronic ink displays. In fact, since 2000, various electronic ink technology products have appeared one after another. In November 2000, Lucent Technologies cooperated with Electronic Ink Corporation to display the first soft electronic ink display with the same hardness and thickness as the mouse pad. It alternately displays the names of the two companies and the electronic ink company's trademark in a checkerboard style. This demonstration shows an active drive circuit that can be made of plastic and printed on a flexible sheet.

In April 2001, American Electronic Ink Corporation and IBM R&D Department jointly released its first high-resolution active-driven electronic ink display; researchers at Electronic Ink Corporation changed the speed of microcapsule color change faster than the original design. 10 times.

In May 2001, U.S. electronic ink company and Japan Toppan Printing Co., Ltd. introduced a color electronic ink prototype display. Japan's Toppan Printing Co., Ltd.'s color filter array technology has been widely used in the standard LCD, using this technology, the electronic ink display can show eight colors.

In 2004, the latest achievement of electronic ink company is an electronic device applied to electronic newspapers, wearable computer screens, portable information terminal screens, electronic dictionaries, e-books and smart ID cards. A company spokesperson stated that this is as far