High-Resolution Technology Opens the Door to New Displays

Elizabeth M. Lockyer

SUNNYVALE, Calif. -- A fundamentally new approach to display technology may revolutionize those alphanumeric readouts on phones, microwaves, pagers and dashboards. In response to increasing demands for higher information content and higher resolution in ever-smaller spaces, Silicon Light Machines, formerly Echelle Inc., has developed a low-cost, reflective display based on Grating Light Valve technology.
In contrast to display technology that uses cathode ray tubes, which are big, heavy and analog, and liquid crystal displays, which are also analog, Grating Light Valve technology is entirely digital. And like Texas Instruments Inc.'s digital micromirror display technology, the new technology uses a silicon-based, light- modulating device that relies on micro-electromechanical systems techniques.
Robert W. Corrigan, vice president of marketing at Silicon Light Machines, said, "The main differences between TI's technology and ours is that the grating light technology moves a very small mass over a very small distance." Texas Instruments' tilting mirrors require a large flap of metal to move through an angle of about 20°, reflecting light either away from or into the receiving optics.
Grating light technology creates an image by reflecting a standard light source off tiny (Corrigan did not want to be any more precise than "tens of microns") aluminum-coated silicon-nitride ribbons onto a screen. The ribbon structures are formed on the surface of a silicon wafer using standard, very large scale integration production equipment. In response to electrical signals, these structures can be snapped between "on" and "off" states. When all the ribbons are up, the pixel is on; an alternating up/down mode turns the pixels off.
Corrigan said, "This motion is what precisely controls the reflective properties of the chip's surface and produces the high contrast and resolution."
Silicon Light Machines is also looking beyond the home and office application of its new display technology to the obvious commercial applications in convention hall and sports projection systems.