Electrophoretic
An electrophoretic display forms visible images by rearranging charged pigment particles using an applied electric field.
In the simplest implementation of an electrophoretic display, titanium dioxide particles approximately one micrometer in diameter are dispersed in a hydrocarbon oil. A dark-colored dye is also added to the oil, along with surfactants and charging agents that cause the particles to take on an electric charge. This mixture is placed between two parallel, conductive plates separated by a gap of 10 to 100 micrometres. When a voltage is applied across the two plates, the particles will migrate electrophoretically to the plate bearing the opposite charge from that on the particles. When the particles are located at the front (viewing) side of the display, it appears white, because light is scattered back to the viewer by the high-index titania particles. When the particles are located at the rear side of the display, it appears dark, because the incident light is absorbed by the colored dye. If the rear electrode is divided into a number of small picture elements (pixels), then an image can be formed by applying the appropriate voltage to each region of the display to create a pattern of reflecting and absorbing regions.
Examples of commercial electrophoretic displays include the high-resolution active matrix displays used in the Amazon Kindle, Barnes & Noble Nook, Sony Librie, Sony Reader, and iRex iLiad e-readers. These displays are constructed from an electrophoretic imaging film manufactured by E Ink Corporation.
The EPD technology has been developed also by Sipix and Bridgestone/Delta. SiPix Imaging Inc. (達意科技) is now part of AU Optronics Corp. (友達光電), 1 of the 3 largest LCD-panel manufaturers in the world. Other than E-Ink's 0.04mm-diameter micro-capsule structure, Sipix's is 0.15mm-diameter microcup. On the other side, Bridgestone Corp.'s (ブリヂストン) Advanced Materials Division has been cooperating with Delta Electronics Inc.'s (台達電子工業) Delta Optoelectronics Inc. (翰立光電) in developing the Quick Response Liquid Powder Display (QR-LPD) technology.The Motorola MOTOFONE F3 was the first mobile phone to use the technology, in an effort to help eliminate glare from direct sunlight during outdoor use.
Electrophoretic displays can be manufactured using the Electronics on Plastic by Laser Release (EPLaR) process developed by Philips Research to enable existing AM-LCD manufacturing plants to create flexible plastic displays.
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