University of California

Leland Stanford Junior University

Echelon Corporation

International Business Machines Corporation

Benjamin W Chui

Shuvo Roy

Thomas W Kenny

Rishi Kant

Kenneth G Goldman

Philip H Sutterlin

Walter J Downey

Amy O Hurlbut

J Marcus Stewart

Aaron Partridge

Daniel Rugar

Robert A Dolin

Harry Jonathon Mamin

Alissa M Fitzgerald

Thomas William Kenny, Jr

Nathan Wright

Jospeh Kurth Reynolds

Filtration membrane with improved mechanical stability and increased resistance to pressure is provided. The filtration membrane is useful for in vivo implantable filtration devices, such as, an artificial kidney. In vivo implantable filtration devices are also provided.

In vivo blood filtration membranes and devices

The present technology provides micro fabricated filtration devices, methods of making such devices, and uses for microfabricated filtration devices. The devices may allow diffusion to occur between two fluids with improved transport resistance characteristics as compared to conventional filtration devices. The devices may include a compound structure that includes a porous membrane overlying a support structure. The support structure may define a cavity and a plurality of recesses formed in a way that can allow modified convective flow of a first fluid to provide improved diffusive transport between the first fluid and a second fluid through the membrane.

Low resistance microfabricated filter

The present technology provides microfabricated filtration devices, methods of making such devices, and uses for microfabricated filtration devices. The devices may allow diffusion to occur between two fluids with improved transport resistance characteristics as compared to conventional filtration devices. The devices may include a compound structure that includes a porous membrane overlying a support structure. The support structure may define a cavity and a plurality of recesses formed in a way that can allow modified convective flow of a first fluid to provide improved diffusive transport between the first fluid and a second fluid through the membrane.

A micromachined accelerometer for measuring acceleration in a direction parallel with the plane of the accelerometer substrate. The accelerometer has a strain-isolation pedestal, a flexure attached to the pedestal, and a proof mass attached to the flexure. The pedestal is wider than the flexure and does not bend when the device is under acceleration. The pedestal serves to isolate the flexure from substrate strain which may be caused by device packaging or temperature variations. Preferably, the joint between the pedestal and flexure, and the joint between the flexure and proof mass are smoothed to prevent stress concentration. The joints have a radius of curvature of at least 1 micron. A piezoresistor is located in one sidewall of the flexure. Alternatively, two piezoresistors are located on the flexure, with one on each sidewall. In this embodiment, a center-tap connection is provided to the point where the two piezoresistors are connected. The present invention includes devices having two accelerometers with Large proof masses and two reference accelerometers having very small proof masses. The four accelerometers are electrically connected in a wheatstone bridge circuit. Also, in the embodiment having two piezoresistors on one flexure, two accelerometers (with a total of four piezoresistors) are electrically connected in a Wheatstone bridge circuit to provide accurate acceleration sensing.

In-plane micromachined accelerometer and bridge circuit having same

A method of forming electrical elements on the sidewalls of deformable micromechanical structures such as flexible, high aspect ratio beams. The micromechanical structure is made of a semiconductor material such as silicon. The method includes angled ion implantation at an angle nonnormal to the substrate surface. The angle ensures that ions are implanted into appropriately oriented sidewalls. Multiple ion implantations can be performed to form electrical elements into different sidewalls. Masking techniques can be used to restrict the locations where ions are implanted. Alternatively, several different types of ion diffusion can be used to expose the sidewall in selected regions. The present invention can form conductive pathways which are continuous between perpendicular surfaces. This enables electrical elements on vertical surfaces to communicate with electronics on horizontal surfaces, for example. The dopant ion concentration and ion species can be controlled to form many different electrical elements. Resist masking techniques can be used to mask sidewall areas not desired to have electrical elements. The present invention can form piezoresistors, conductive paths, resistors, diodes, and capacitor electrodes, for example, on desired areas of a micromechanical structure sidewall.

Method of making electrical elements on the sidewalls of micromechanical

A micromachined structure providing for independent vertical and lateral deflection sensing. The structure uses high aspect ratio ribs which bend much more easily in one direction than in other directions (i.e., have a predominant direction of compliance). One or more ribs are combined to form beams which also have one predominant direction of compliance. Two such beams are bonded end to end, and one end of the beam pair is bonded to a base. The beams are oriented orthogonally to one another such that they independently bend to vertical and lateral external forces. Further, three dimensional force sensing can be accomplished by adding a third beam. Sensors can independently sense the bending in each beam and thereby independently measure the dimensional components of bending forces applied to the free end of the structure. In the preferred embodiment, piezoresistive sensors are formed on the ribs comprising the beams. The piezoresistors can be made by ion-implantation, for example. Measurement of the change in resistance of the sensors is then a measure of the beam deflection and the external force. The resistances of the sensors can be measured independently. Other sensing means include voltage measurement of piezoelectric effects, optical deflection and interference sensing techniques, and capacitive deflection sensors.

Micromachined cantilever structure providing for independent

An atomic force microscope (AFM) based data storage disk drive uses a cantilever structure that provides independent detection of vertical and lateral motion of the AFM tip as a track with data marks moves past the tip. The vertical detection of the tip deflection toward and away from the disk surface is used for data detection of the data marks that form the tracks. The lateral detection of the tip deflection in a direction generally parallel to the plane of the disk surface is used as the input signal to a tracking servo control system to maintain the tip on a data track. The cantilever structure includes a base connected to the disk drive actuator, a beam made up of a plurality of ribs that have their fixed ends connected to the base, and a probe connected to the free ends of the ribs. The beam ribs have piezoresistors connected to electrical circuitry that detects a resistance change as the ribs are bent laterally. The probe includes the AFM tip located at its free end and piezoresistors connected to electrical circuitry that detects a resistance change as the probe is bent vertically. The data tracks are a series of data marks in the form of pits or bumps separated by portions of the disk surface that serve as lands. Alternatively, the data tracks are formed as continuous grooves in the disk surface with the data pits or bumps located at the bottoms of the grooves.

Atomic force microscopy data storage system with tracking servo from

In a communications system, an apparatus and method for detecting a valid signal from noise. An adaptive threshold is used to qualify a received signal. The adaptive threshold is set according to the number of false detects occurring within a given time interval. The number of false detects is initially determined by a quick qualification process. This initial number is subsequently adjusted by a more accurate qualification process. The transmitted signal is modulated with a particular pattern. Upon receiving the signal, it is demodulated to retrieve that pattern. The demodulated pattern is correlated against multiple reference patterns and combined to provide a measure of peak correlation that is independent of pattern phase. Furthermore, a tone detector is used to distinguish valid signals from interfering tones. Two different types of detection methods are performed in parallel. One is based on the energy of the received signal, whereas the other is based on the correlation of the received signal.

Apparatus and method for detecting a signal in a communications system

An apparatus for snubbing or blanking digital signals representing a band of signals that includes an encoded carrier signal transmitted over a power line. An average signal level is compared with the instantaneous signal level to develop a blanking circuit control signal. Additionally, snubbing occurs in the circuit which determines the average signal level to prevent noise from building-up the average signal level. A hold-off signal is used in this circuit to prevent the average signal level from being latched permanently low. A unique infinite impulse filter subtracts out the D.C. offset thereby improving the dynamic range of the blanking. Additionally, the average signal level is used by AGC logic to control the gain at the front end of the apparatus. The state and switching of the AGC is controlled to minimize errors.

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Sunnyvale, CA, United States of America

Benjamin W Chui