Electronic Paper : How real are they?
Recently a lot of attention has been paid to a type of electronic display called electronic paper. This differs from the usual electronic displays and in that there is no backlight - the information displayed is viewed by reflection of light from an external source. The advantage of this technology over conventional displays such as LED or LCD displays is that they do not appear dim in bright light, and offers a better angle for viewing. Current electronic paper displays offer contrast ratios similar to printed paper, making them easier to read even in very bright light. Another advantage is that they can hold an image for a long time without any power consumption. These advantages have been showcased in ebook readers that carry hundreds of books and offer easy reading. Several publishing companies like Amazon and Barnes and Noble have invested heavily in this technology making them very popular.
E Ink Holdings, a major company that is involved in developing electronic paper has announced a new technology that makes large (13.3 inch) flexible displays. These plastic displays were developed by Sony and weighs less than half of similar LCD displays. Other companies like Plastic Logic, Samsung and LG are also actively involved in the developing such technologies. Flexible electronic displays are advantageous over current laptop and tablet displays since they offer both portability and energy efficiency.
The basic technology that is used in electronic paper involves a dipole bead that is black on one side and white on the other, and floats in an emulsion between two thin sheets. The black side can be displayed by applying appropriate charges in the desired pattern on this sheet. Color displays are often created using color filters. Although electronic papers that reproduce color images have been developed, they are not perfect yet and are costlier.
Several companies have developed different variations of electronic papers and are in the process of perfecting them for efficient commercial use. Commercial applications that use electronic paper displays include ebook readers, watches, electronic shelf displays, status displays technology etc. It has even been tried by one newspaper in Europe for publishing a limited edition electronic copy.
Although it has several advantages, electronic paper has many disadvantages that have kept it away from mainstream electronics. A major drawback is the low refresh rate of the display that makes it unsuitable to show fast changing images such as a videos or cursor movements on a user interface while using a mouse. Another problem is retention of ghost images from previous displays that require flashing between images. Electronic papers are still being developed and refined by several companies for better usability.
An important progress in the field of electronic paper is recent development of flexible displays using plastic components. This allows displays that can be bent. However this doesn't mean we will be handling these displays like a newspaper - folding and rolling and squatting flies. They will still be delicate displays that need to be handled with care. Moreover a battery will need to be incorporated into this system as power source. Although flexible battery technology is being developed by companies they are far from perfect and will not be available in products in any recent future.
In addition to the electronic paper technology, Samsung has recently developed flexible TFT LCD screen that uses backlighting. They will offer better images than electronic paper and can be used for displaying videos and user interfaces. However they will still lack the energy efficiency that electronic paper offers.
Written By: Sujatha S., Canada (PHD Life Sciences)
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Edited by: Rajesh Bihani ( Find me on Google+ )