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Electronic paper display (EPD) is a technology that uses an electrically-charged surface replicating the look and feel of ink on paper. EPDs are very thin and need power only if a new image is requested. Unlike conventional displays that make use of backlighting technology for illuminating pixels, an EPD uses a scientific phenomenon called electrophoresis, which refers to the motion of electrically-charged molecules within an electrical field.
EPD makes use of microcapsules containing granules of white pigment having a positive charge and black pigment having a negative charge. These microcapsules are suspended in a clear fluid placed in between a thin layer of plastic materials that are laminated on the micro-circuitry and electrode layers.
To form a display, the electrodes are charged positive or negative, per the image requirement. When positively charged, the white pigment granules move to the capsule’s top, making the surface appear white. Reversing the process makes the surface appear black. All these circuits form a screen having a calculable resolution. This can be managed by a graphics chip or display driver.
EPD is used in e-books, smart card displays, status displays, mobile phones, electronic shelf labels, e-newspapers, wrist watches, etc.