Interferometric modulator display

Working principle

The basic elements of an IMOD-based display are microscopic devices that act essentially as mirrors that can be switched on or off individually. Each of these elements reflects only one exact wavelength of light, such as a specific hue of red, green or blue, when turned on, and absorbs light (appears black) when off. Elements are organised into a rectangular array in order to produce a display screen.

An array of elements that all reflect the same color when turned on produces a monochromatic display, for example black and red (in this example using IMOD elements that reflect red light when "on"). As each element reflects only a certain amount of light, grouping several elements of the same color together as subpixels allows different brightness levels for a pixel based on how many elements are reflective at a particular time.

Multiple color displays are created by using subpixels, each designed to reflect a specific different color. Multiple elements of each color are generally used to both give more combinations of displayable color (by mixing the reflected colors) and to balance the overall brightness of the pixel.

Because elements only use power in order to switch between on and off states (no power is needed to reflect or absorb light hitting the display once the element is either reflecting or absorbing), IMOD-based displays potentially use much less power than displays that generate light and/or need constant power to keep pixels in a particular state. Being a reflective display, they require an external light source (such as daylight or a lamp) to be readable, just like paper or other electronic paper technologies.

Details

A pixel in an IMOD-based display consists of one or more subpixels that are individual microscopic interferometric cavities similar in operation to Fabry–Pérot interferometers (etalons). While a simple etalon consists of two half-silvered mirrors, an IMOD comprises a reflective membrane which can move in relation to a semi-transparent thin film stack.{{citation

For a practical RGB color model (RGB) display, a single RGB pixel is built from several subpixels, because the brightness of a monochromatic pixel is not adjusted. A monochromatic array of subpixels represents different brightness levels for each color, and for each pixel, there are three such arrays: red, green and blue.

Development

The IMOD technology was invented by Mark W. Miles, |access-date=5 May 2011|publisher=EE Times|date=26 July 2009

Future IMOD panels manufacturers include Qualcomm in conjunction with Foxlink, having established a joint-venture with Sollink (高強光電) in 2009 with a future facility dedicated to manufacturing IMOD panels. Production for this began in Jan 2011, with the fabricated panels intended for devices such as e-readers.

As of 2015, the IMOD Mirasol display laboratory in Longtan, Taiwan, formerly run by Qualcomm, is now apparently run by Apple. Daniel Eran Dilger. "Apple has taken over Qualcomm's IMOD Mirasol display lab in Taiwan". 2015.

Uses

IMOD displays are now available in the commercial marketplace. QMT's displays, using IMOD technology, are found in the Acoustic Research ARWH1 Stereo Bluetooth headset device, the Showcare Monitoring system (Korea), the Hisense C108, and MP3 applications from Freestyle Audio and Skullcandy. In the mobile phone marketplace, Taiwanese manufacturers Inventec and Cal-Comp have announced phones with mirasol displays, and LG claims to be developing "one or more" handsets using mirasol technology. These products all have only two-color (black plus one other) "bi-chromic" displays. A multi-color IMOD display is used in the Qualcomm Toq smartwatch.

References

Bibliography

References

1. Gabryel. (July 7, 2010). "Qualcomm mirasol launch its color e-Reader". GeeksHive blog.
2. Simonite, Tom. (November 15, 2011). "E-Reader Display Shows Vibrant Color Video". Massachusetts Institute of Technology.
3. Waldrop 2007
4. Watters, Ethan. (June 12, 2007). "Product design, nature's way". Cable News Network.
5. (September 10, 2004). "Technology Briefing: Deals: Qualcomm To Acquire Iridigm". The New York Times.
6. [http://www.scientificblogging.com/newswire/hisense_reveals_design_of_first_mobile_phone_to_incorporate_mirasol_displays Ultra Low-power Handset to Begin Shipping in China in 2008] {{webarchive. link. (2016-05-15 PRNewswire, Barcelona, Spain, February 11)