SLI eliminates the need for touch in MEMS applications

R Colin Johnson, EE Times -- EDN, January 19, 2012

The next promising frontier in emerging ubiquitous MEMS applications, SLI (structured-light illumination), may revolutionize metrology applications by removing the need for touch with MEMS. The technology is both smaller and more precise than conventional approaches. Texas Instruments, with its million-mirror DLPs (digital-light processors), is a pioneer in this segment.


TI previously has supplied OEM development kits that bundled its DLPs with algorithm libraries that can recognize 3-D shapes, surfaces, contours, roughness, and discontinuities, enabling fast, accurate, noncontact 3-D scanning and recognition systems that operate with light sources ranging from ultraviolet to nearly infrared. At this year’s CES (Consumer Electronics Show) in Las Vegas this month, TI planned to show its new DLP LightCrafter development platform, which uses almost 500,000 micromirrors to simultaneously illuminate almost anything with structured light, allowing almost-instant characterization and recognition of 3-D objects without touching them.

According to TI customer Mike Troy, chief executive officer of FlashScan3D, DLP technology allows FlashScan3D to capture greater detail in fingerprints with higher accuracy than with other SLI approaches, thus reducing the possibilities of technician error and fraud. “The new DLP LightCrafter development module can scan faster; store data internally versus on a laptop or a separate storage device; and, because of its size, enable even smaller, more portable SLI applications,” says Troy.

YoungOptics, which manufactures TI’s DLP optical engine for OEMs building projection TVs, also manufactures the LightCrafter plug-and-play module. Using TI’s DLP 0.3 WVGA chip set, OEMs can use the LightCrafter for R&D, but it can also serve as the main subsystem in finished enduser products. The LightCrafter includes a 415,872-micromirror DLP chip as a second custom controller ASIC; a DaVinci digital video processor with its own 128 Mbytes of NAND-flash memory for pattern storage; and a configurable I/O trigger for integrating cameras, sensors, and the other peripherals for SLI.

Developers can also add an optional FPGA to accelerate displayed SLI patterns to as fast as 4000/sec. An integrated LED array for red, green, and blue completes the LightCrafter by enabling it to output as much as 20 lumens of light. OEMs use embedded Linux to develop their software for the DaVinci processor in the LightCrafter, which will cost $600 when it becomes available after this month’s SPIE (International Society for Optics and Photonics Engineering) West, in San Francisco.

Texas Instruments