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About this Article
Written by: Richie Aquino
Written on: April 26th, 2005
Tags: electrical engineering, entertainment, material science
Thumbnail by: Adpowers/Wikimedia Commons
About the Author
Richie Aquino was an Aerospace Engineering student at USC in the class of 2007. He obtained a double major in Physics from the University of San Francisco, from which he transferred in 2005.
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Volume IX Issue III > Reflecting on the Mirrors
Advertisements for some new types of televisions claim that their superb picture quality is due to “the mirrors.” These mirrors are on the order of microns wide, and millions of them reside in the back of DLP televisions. This way of projecting the light source is a cutting-edge method (over LCD and Plasma) that allows for the brightest picture and most highly powered light sources, resulting in an even larger screen. Texas Instruments is the only present force in televisions powered by this technology, but a new concept from Daewoo Electronics has emerged and may take the product even further.

Introduction

Like an inexplicably mixed-up dream, after hours of inundation from today‘s media-enriched environment, a girl has a conversation with an elephant in a field full of daisies. She opens a box from which a brilliant beam of light shoots towards the sky, and she whispers, “It‘s amazing. It‘s the mirrors” [1]. In this advertisement, the little girl lets the viewer in on the secret of Digital Light Processing (DLP) television, which uses millions of microscopic mirrors to project images onto the screen. Millions of mirrors work in harmony to create vivid pictures, yet the entire array can fit within a box only centimeters wide. To a person unfamiliar with how this might work, the DLP television does seem like a cryptic black box of magic. Actually, the principles behind how these televisions work are rather straightforward. And now, there may even be a better and simpler way to achieve similar results.
The most complicated aspect of these televisions is the manufacturing and integration of the systems due to the emerging field of microelectromechanic​al systems (MEMS). These tiny devices are unconventionally fabricated, etched with light and chemicals rather than tools. Still, the Digital Micromirror Device (DMD) may become one of the more easily understood applications of MEMS in daily life due to its simpler mechanical principles. Small-scale devices have become much more prevalent in recent years due to wireless technology, increased memory capacity, and shrinking volume.

History

DMD technology was originally developed by Texas Instruments in 1987, and it has recently become a major player in the high-definition television (HDTV) market with the incorporation of color and an aggressive advertising campaign. Conceptually, the micromirror has the most potential for larger, brighter displays, surpassing the more standard liquid crystal and plasma reflecting systems. These other types of systems are limited against high-powered light sources because absorption of light in these materials generates a lot of heat within the display [2]. Micromirrors have the added benefit of higher optical efficiency, meaning almost all the light is reflected and not absorbed. The result is a brighter picture for a given light source compared to liquid crystal or plasma displays. If the picture is brighter, there is more headroom to make the display larger, since the projection can expand farther before becoming dark.