Wednesday, January 27, 2010

MEMS Devices for Slow Movers, Anti-Fouling Detection, Imaging and More Make for Robust Market

The global market for MEMS devices and nanotechnology is well established and currently is over ten billion dollars per year. Currently most microeletromechanical systems (MEMS) are constructed using modified versions of VLSI technology wherein layers of silicon nitride, silicon dioxide, and polysilicon are successively grown and patterned using photolithography. This process is inherently costly and time consuming, as there are typically as many as seven growth and lithography steps. The process is also limited by the resolution of the lithography and wet or dry etch processes to the extent that nanoscale devices are not easily achievable.

The development of Micro-Electro-Mechanical Systems (MEMS) technology has enabled manufacturers to produce inertial sensors (e.g., accelerometers) of sufficient size, cost, and power consumption to fit into portable electronic devices. Such inertial sensors can be found in a limited number of commercial electronic devices such as cellular phones, portable music players, pedometers, game controllers, and portable computers.  More than 16,770 U.S. Patents reference MEMS devices in their descriptions and specifications. 

Some of those granted on January 26th are noted below.

DP Technologies, Inc. (Scotts Valley, CA) earned U.S. Patent 7,653,508 for a MEMS based step counter that operates at a slow pace and also at a very fast pace when tracking a person’s motions who is rollerblading. Step counting devices are often confused by motion noise experienced by the device throughout a user's daily routine. This noise causes false steps to be measured and actual steps to be missed in conventional step counting devices. Conventional step counting devices also fail to accurately measure steps for individuals who walk with a slow gait. Such step counting devices can fail to operate for seniors and others walking at a slow pace.

Inventors Philippe Kahn, Arthur Kinsolving, Mark Andrew Christensen, Brian Y. Lee and David Vogel developed DP Technologies MEMs method for monitoring human activity.  The device uses an inertial sensor includes continuously determining an orientation of the inertial sensor, assigning a dominant axis, updating the dominant axis as the orientation of the inertial sensor changes, and counting periodic human motions by monitoring accelerations relative to the dominant axis. It is not easily confused.

Avago Technologies ECBU IP (Singapore) Pte. Ltd. (Singapore, SG) garnered U.S. Patent 7,653,214 for a MEMS based accelerometer that captures multiple frames of image information and uses the image information to generate acceleration data related to an object. In particular, multiple image frames are used to determine relative movement between a target and an image collection system. The relative movement between the target and the image collection system is tracked over time to generate acceleration data related to the object, says inventors Dale Schroeder  and George M Clifford, Jr.

Qualcomm MEMS Technologies, Inc. (San Diego, CA) added U.S. Patent 7,652,814 to its portfolio for a MEMS device with integrated optical element.  MEMS devices are fabricated by a method that involves forming an optical element (e.g., etalon) over a substrate and then forming a light modulating element (e.g., interferometric modulator) over the optical element, say inventors Fan Zhong,  Chun-Ming Wang and Stephen Zee.  The MEMS optical element may be implemented in any device that is configured to display an image, whether in motion (e.g., video) or stationary (e.g., still image), and whether textual or pictorial. It can also be used in non-display applications such as in electronic switching devices.

Sandia Corporation (Albuquerque, NM) was awarded U.S. Patent 7,652,547 for a microelectromechanical resonator and its fabrication method.  Inventors Jonathan W. Wittwer and Roy H. Olsson disclose a techniques for robust fabrication of a microelectromechanical (MEM) resonator. In this method, a pattern of holes is formed in the resonator mass with the position, size and number of holes in the pattern being optimized to minimize an uncertainty .DELTA.f in the resonant frequency f.sub.0 of the MEM resonator due to manufacturing process variations (e.g. edge bias). A number of different types of MEM resonators are disclosed which can be formed using this method, including capacitively transduced Lame, wineglass and extensional resonators, and piezoelectric length-extensional resonators.

Fujifilm Corporation (Tokyo, JP) details a piezoelectric actuator for inkjet print heads in U.S. Patent 7,652,412. According to inventor Yasukazu Nihei, the MEMS devices is comprised of: a supporting substrate; a thermal stress controlling layer which is formed on the supporting substrate; and a piezoelectric body which is formed as a film onto the thermal stress controlling layer on the supporting substrate at a higher temperature than room temperature, wherein the thermal stress controlling layer reduces a film stress induced by formation of the piezoelectric body.

Broadcom Corporation (Irvine, CA) received U.S. Patent 7,653,358 for an integrated circuit (IC) comprising: a on-chip pressure sensing circuit that generates a pressure signal based on an atmospheric pressure; and an RF transceiver coupled to generate an outbound RF signal from outbound data and to generate inbound data from an inbound RF signal, wherein at least one of the generating the outbound RF signal and generating the inbound data is in accordance with the pressure signal. According to inventor Ahmadreza Reza Rofougaran , the on-chip pressure sensing circuit is implemented with microelectromechanical systems (MEMS) technology.

IMEC (Leuven, BE) inventor Wolfgang Eberle details a wireless communication device in U.S. Patent 7,653,412.  The device comprises a digital circuit, an analog circuit, and a control circuit. The digital circuit is arranged to perform digital processing in a signal path. The analog circuit is arranged to perform analog processing in the signal path. The control circuit is arranged to receive control signals as input and arranged to provide output control signals for the analog circuit. The analog circuit includes a RF Micro Electro-Mechanical System (MEMS) device.

Texas Instruments Incorporated (Dallas, TX) reveals a method for micromechanical device fabrication in U.S. Patent 7,651,734.  According to inventor Simon Joshua Jacobs, several of the micromechanical devices, which typically are microelectromechanical systems or MEMS, are fabricated  on a common wafer. Typical micromechanical devices are fabricated on one or more sacrificial layers. The sacrificial layers typically are photoresist. The sacrificial layers provide support for the various components of the micromechanical device during the fabrication process.  

General Electric Company (Niskayuna, NY)  inventors Marko Baller,  Marcin Alexy, Glenn S. Claydon,  Peter Joseph Codella, Stacey Kennerly, Kuna Kishore, Anis Zribi, Guiju Song, Shivappa Goravar and Ajit Achuthan developed a MEMS device to detect formation of a fouling layer of filtration layers in heat exchange devices. According to another embodiment in U.S. Patent 7,652,586, a thermal device is provided proximate to a surface where a fouling layer is to be detected. A detector (e.g., a thermometer or vibration detector) may detect a condition associated with the surface, and formation of the fouling layer may be determined based at least in part on the condition.

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