Spatial light modulators

A digital spatial light modulator produced by Texas Instruments (TI; Dallas, TX), previously distributed only to a limited number of OEM display manufacturers is now available to researchers in the form of an evaluation kit. Digital micromirror devices (DMDs) are lithographically produced modulators consisting of two-dimensional arrays of independently addressable 16 ¥ 16-µm mirrors that reflect incident light (see Laser Focus World, Aug. 1994, p. 20). Each mirror is mounted on a support

Spatial light modulators

Kits bring digital micromirrors to new applications

A digital spatial light modulator produced by Texas Instruments (TI; Dallas, TX), previously distributed only to a limited number of OEM display manufacturers is now available to researchers in the form of an evaluation kit. Digital micromirror devices (DMDs) are lithographically produced modulators consisting of two-dimensional arrays of independently addressable 16 ¥ 16-µm mirrors that reflect incident light (see Laser Focus World, Aug. 1994, p. 20). Each mirror is mounted on a support post that is in turn mounted on a yoke attached to a pair of torsion hinges that permit the mirror to tilt from 0° to 10° (see Fig. 1). Mirror position is electrostatically controlled--in the "on" position (0° of tilt), the mirror reflects the beam along the optical axis of the system; in the "off" position (10° of tilt), the mirror deflects the beam.

These devices have previously been unavailable to the general researcher because TI has been targeting the display market. Now, two different digital light processing (DLP) kits allow researchers to evaluate the technology for other applications. The basic DL¥Digital Video Subsystem includes a DMD image processing board with a 640 ¥ 480 array, a light source, a color filter system, drive electronics, power supply, digital interface card, control software, and full documentation. The subsystem includes all components necessary to interface with a PC.

The second kit includes an optical assembly to focus light onto the DMD chip. When combined with a video graphics source, the system can simulate the operation of a front or rear projection DL¥VGA subsystem (see Fig. 2 on p. 50).

Current areas for investigation with the evaluation kits include confocal microscopy, holographic memory systems, optical computing, optical switching, optical pattern recognition, and three-dimensional displays. The design allows the DMD board to be operated as far as 6 ft away from the computer, making it suitable for laboratory applications.

The company emphasizes that the kits are for research and evaluation purposes only. Digital micromirror devices are still not available for commercial purchase outside of the projection-system OEM agreements currently underway. Kits are available to selected applicants, and prices begin at $5200; for more information, see the TI website at http://www.ti.com/dlp.

Kristin Lewotsky

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