Photonics West Plenary: Building a better MEMS/MOEMS
January 22, 2008, San Jose, CA--Reliability testing throughout the entire product-development cycle is key to building a better MEMS/MOEMS, according to Michael Douglass of Texas Instruments (TI; Dallas, TX).
January 22, 2008, San Jose, CA--Reliability testing throughout the entire product-development cycle is key to building a better MEMS/MOEMS, according to Michael Douglass of Texas Instruments (TI; Dallas, TX). In his plenary session presentation on Monday at Photonics West, Douglass outlined the failure-analysis processes that TI has implemented for years to ensure the reliability lifetimes of its Digital Light Processing (DLP) and Digital Micromirror Device (DMD) technologies, citing some pretty impressive statistics resulting from these testing procedures. Such procedures are particularly important, he noted, as MEMS/MOEMS technologies move increasingly into the consumer electronics market via such devices as the Wii and the iPhone, both of which utilize acclerometers.
As the MOEMS/MEMS industry continues to establish itself as a viable alternative to the macro world, reliability is always a concern, Douglass noted. There are several emerging market opportunities right now for MOEMS/MEMS to gain a foothold; applications such as mobile media, consumer electronics, biomedical, and homeland security are all showing great interest. However, these applications are also some of the most demanding when it comes to reliability assurance, he added.
Douglass outlined the Failure Modes & Effects Analysis (FMEA) process utilized at TI to create a new approach to reliability analysis that he contends yields much better results. The idea, he says, is to think negatively to force a positive outcome.
"FMEA requires a different mindset than the typical design approach," he said. "With FMEA, you want to find failures. Making something fail on purpose can help guarantee success. If all you do is run a test to try to get (a feature) to pass, you have no idea how close you are to failure."
For example, TI has been running accelerated reliability testing for years on the MEMS components utilized in its DLP and DMD devices, such as the hinges that help control the mirrors that are at the heart of these devices. Consistent long-term performance of these hinges is critical, Douglass noted, given that a typical DLP TV utilizes 1 million mirrors, while a digital cinema system utilizes 6 million mirrors. Douglass was proud to announce that in each case, TI's mirrors have consistently shown 99.9999% reliability.
"It is very rare to find even one defective pixel," he said. "That is a reliable product."
As MEMS/MOEMS technologies become increasingly ubiquitous--Douglass pointed out that both the Wii and the iPhone utilize MEMS-based accelerometers, for example--reliability becomes that much more important. Consumers don't buy technology, he said--they buy products. This means that even at the components level, product developers need to focus on the end-user experience.
"In MEMS/MOEMS, the technology is ripe for exploration (in terms of reliability testing)," he said. "Temperature, voltage, vibration, shock--you can look at all of these just to see what the weaknesses are. And studying failure helps you succeed."
--Kathy Kincade, Sr. Editor, Laser Focus World, and Editor in Chief, BioOptics World