The Evolving MOEMS IP Landscape

Considered a futuristic vision for decades, micro-electro-mechanical systems (MEMS) emerged from the shadow of microelectronics in the late 1980s and eventually gave rise to a new field in its own right, optical MEMS, also known as MOEMS, which combines micro-optical elements with silicon-based microelectronics and micromachining technology. Leveraging the benefits of the semiconductor infrastructure in terms of manufacturing and cost structure, MOEMS devices are becoming increasingly attractive to a wide variety of applications, enabling more compact systems, and increased levels of integration, functionality, and performance.

Investigating MOEMS intellectual property (IP) reveals significant changes and trends in the patent landscape, as well as key players in the projection display and television, optical data storage, microscopy, microspectrometry, and photolithography application sectors.

U.S. and European IP issuance in the MOEMS field has increased exponentially since the 2000 telecom downturn, with the vast majority of patents (90%) being granted by the United States Patent and Trademark Office (USPTO) to commercial organizations. In general, the growth of MOEMS IP has tracked with the overall growth of MEMS IP, as the MOEMS year-to-year level of patent activity over the past five years has been roughly a quarter that of MEMS (see figure) with a 40% compounded annual growth rate from 1990 through 2006.

To date, the MOEMS portfolio has grown to include 2500 patents, accounting for more than 25% of all issued MEMS patents, with more than 500 independent corporate, academic, or government patent assignees. MOEMS patents held by the top 10 corporate patent assignees account for nearly 30% of all U.S. and European MOEMS patents issued to date. As the undisputed leader in digital micro-mirror device (DMD) technology, and with R&D efforts in spatial light modulators (SLMs) commencing in 1977, Texas Instruments (TI; Dallas, TX) holds the most significant MOEMS patent estate with greater than 10% IP share.

Since the telecom downturn, MOEMS IP associated with optical components for all-optical telecommunications systems continues to be developed (Lucent Technologies, Agere Systems, JDS Uniphase, Nortel Networks). Today a large portion of MOEMS IP development focuses on projection display and TV applications. With the initial IP granted in 1986 (Larry J. Hornbeck; U.S.#4,566,935) and profitable production based on this IP occurring a decade later, TI's DMD is at the core of the company's Digital Light Processing™ technology, an all-digital display technology used in projectors and TVs alike.

Other competing IP for display applications includes Silicon Light Machines (San Jose, CA) grating light valve (GLV™) technology, which is based on switchable diffraction gratings (David M. Bloom; U.S.#5,841,579; 1998), Reflectivity's (Sunnyvale, CA) proprietary core micro-mirror array and micro-assembly technologies, Miradia's (Sunnyvale, CA) all-silicon micro-mirror array, which drives large displays for front projectors and rear projection TVs, and Qualcomm's (San Diego, CA) proprietary interferometric modulator display technology (Mark W. Miles; U.S.#6,040,937; 2000), which is similar to GLV™.

Seagate Technology (Scotts Valley, CA) and TI are major MOEMS IP holders in optical data storage. While TI's IP focuses on integrating DMDs into holographic storage systems to act as SLMs allowing high input data rates, Seagate's IP relates to the integration of MOEMS-based tracking actuators in magneto-optical storage systems to improve drive reliability and increase the data density that can be written, thus avoiding the super-paramagnetic limit of magnetic technology.

Other IP developments include MOEMS-based optical pickup head devices (Samsung, General Electric) for recording/reading information in CD/DVD optical storage systems, which integrate micro-mirror devices (LG Electronics) or diffraction grating MEMS technology (InterScience) for realizing lighter, more compact, and more cost-effective systems.

Micro-mirrors are finding their way into microscopy systems, allowing for miniaturization, higher efficiency/resolution, and increased speed, especially in user-defined confocal applications. Leica Microsystems (Wetzlar, Germany), Olympus (Tokyo, Japan), and Carl Zeiss Jena (Jena, Germany) are developing IP associated with confocal laser scanning microscopes with DMD technology at their core.

The recent spike in IP activity in microspectrometry is worthy of mention. Using moving micro-mirrors or gratings, which are capable of using single detectors in the near-infrared spectrum, MOEMS-based spectrometers offer added value in terms of reduced size, robustness and lower cost, making them quite attractive as an alternative to traditional systems. Among the top IP holders, ChemImage (Pittsburgh, PA) is generating IP associated with compact MOEMS-based imaging spectrometers (multi-wavelength, dispersive, birefringent interference, and Fabry-Perot imaging) for chemical and biological applications. Concurrently, Axsun Technologies (Billerica, MA) has secured IP for spectroscopy systems integrating Fabry-Perot tunable filters or other mirror-based resonant tunable filters for compactness and lower power consumption.

New lithography systems geared toward the production of large-area displays are now integrating MOEMS devices to eliminate the trade-off between high-resolution projection imaging and panel size. ASML (Veldhoven, the Netherlands) is currently the IP leader in MOEMS-based lithography and driving the charge in maskless lithography, an emerging submarket benefiting from MOEMS technology. Combining an illumination system, SLMs, and a controller, maskless lithography systems rely on the SLMs to pattern the light before it impinges on an object. In addition to ASML, Anvik (Hawthorne, NY) and Ball Semiconductor (Allen, TX) are generating IP in this area, with some emanating from academia, notably the University of South Florida (Tampa, FL).

The noticeable changes in the MOEMS IP landscape since 2000 reflect an overwhelming shift in focus from developing IP for telecommunications applications to projection display and TV applications. As evidenced by the growing trend in IP issuance and new applications, MOEMS technology promises to revolutionize a myriad of product categories with the integration of such devices adding functionality and enabling lighter, more compact and durable, lower power consumption, and lower cost solutions.

As MOEMS technology matures, we are likely to see additional MOEMS IP granted in diffractive/adaptive optics, photonic crystals, and sub-wavelength structures.