The Future of Electronic Paper: Fast-switching, Full-Color E-Readers
Qualcomm-Mirasol
The Interferometric Modulator (IMOD) element is a simple MEMS (micro-electro-mechanical system) device that is composed of two conductive plates. One is a thin film stack on a glass substrate, the other is a reflective membrane suspended over the substrate. There is a gap between the two that is filled with air. The IMOD element has two stable states. When no voltage is applied, the plates are separated, and light hitting the substrate is reflected as shown above. When a small voltage is applied, the plates are pulled together by electrostatic attraction and the light is absorbed, turning the element black. This is the fundamental building block from which Qualcomm's mirasol displays are made. The color of each element is determined by the size of the gap between the two plates, which leads to the creation of RGB pixels (the blue element has the smallest gap).
IMOD pixels are characterized by bistability (due to electromechanical memory also known as hysteresis), allowing for low power consumption. Finally, switching speeds in the order of microseconds allows for excellent video playback capabilities.
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