Siargo Ltd.

Intpax, Inc.

Other

Gaofeng Wang

Liji Huang

Yahong Yao

Chih-Chang Chen

Naiqian Han

Xiaoping Zhang

Jidong Hou

A micromachined thermal mass flow sensor comprises a high mechanical strength polyimide film as a supporting layer of suspending membrane. The polyimide film provides superior thermal insulating properties to reduce the power consumption of device. Due to the tendency of humidity absorption, the polyimide suspending membrane is double side passivated on both top and bottom surfaces to sustain its long term stability from rush and humid working environment. A thin layer of silicon dioxide deposited by plasma enhanced chemical vapor deposition is overlaid between the silicon nitride and polyimide film to enhance the adhesion property of passivation layers to polyimide surface. With such embodiments, a sturdy and robust micromachined thermal mass flow sensor with high measurement accuracy could be formed.

Robust micromachined thermal mass flow sensor with double side passivated polyimide membrane

An integrated mass flow sensor is manufactured by a process of carrying out a micro-machining process on an N or P-type silicon substrate with orientation &#x3c;100&#x3e;. This mass flow sensor comprises an upstream thin-film heater, an downstream thin-film heater, and a pair of thin-film heat sensing elements, and a thermally isolated membrane for supporting the heaters and the sensors out of contact with the substrate base. This mass flow sensor is operated with three sets of circuits, a first circuit for measuring a flow rate in a first range of flow rates, a second circuit for measuring a flow rate in a second range of flow rates, and a third circuit in a differential configuration for measuring a flow rate in said first range of flow rates or said second range of flow rates, to significantly increase range of flow rate measurements and provide an optional for concentration measurement, while maintains a high degree of measurement accuracy.

Integrated micromachined thermal mass flow sensor and methods of making the same

The current invention generally relates to Micro Electro Mechanical Systems (MEMS) thermal mass flow sensors for measuring the flow rate of a flowing fluid (gas/liquid) and the methods of manufacturing on single crystal silicon wafers. The said mass flow sensors have self-cleaning capability that is achieved via the modulation of the cavity of which the sensing elements locate on the top of the cavity that is made of a silicon nitride film; alternatively the sensing elements are fabricated on top of a binary silicon nitride/conductive polycrystalline silicon film under which is a porous silicon layer selective formed in a silicon substrate. Using polycrystalline silicon or the sensing elements as electrodes, an acoustic wave can be generated across the porous silicon layer which is also used for the thermal isolation of the sensing elements. The vibration or acoustic energy is effective to remove foreign materials deposited on top surface of the sensing elements that ensure the accuracy and enhance repeatability of the thermal mass flow sensing.

Micromachined thermal mass flow sensor with self-cleaning capability and methods of making the same

A device with micromachined (a.k.a. MEMS, Micro Electro Mechanical Systems) silicon sensor to measure gas or liquid concentration in a binary mixture formality is disclosed in the present invention. A process for fabricating the said MEMS silicon concentration sensor, which thereby can greatly reduce the sensor fabrication cost by a batch production, is revealed as well. This MEMS process can mass-produce the sensors on silicon substrate in the ways of small size, low power, and high reliability. In addition to the gas or liquid concentration measurement, the present invention further discloses that the said sensor can also readily measure gas or liquid mass flow rate while record the concentration data, which is not viable by other related working principle.

Micromachined gas and liquid concentration sensor and method of making the same

A mass flow sensor is supported on an N or P-type silicon substrate with orientation &#x3c;100&#x3e;. This mass flow sensor comprises a central thin-film heater and a pair of thin-film heat sensing elements, and a thermally isolated membrane for supporting the heater and the sensors out of contact with the substrate base. The mass flow sensor is arranged for integration on a same silicon substrate to form a one-dimensional or two-dimensional array in order to expand the dynamic measurement range.

Micromachined mass flow sensor and methods of making the same

An integrated mass flow sensor is manufactured by a process of carrying out a micro-machining process on an N or P-type silicon substrate with orientation &#x3c;100&#x3e;. This mass flow sensor comprises a central thin-film heater and a pair of thin-film heat sensing elements, and a thermally isolated membrane for supporting the heater and the sensors out of contact with the substrate base. The mass flow sensor is arranged for integration on a same silicon substrate to form a one-dimensional or two-dimensional array in order to expand the dynamic measurement range. For each sensor, the thermally isolated membrane is formed by a process that includes a step of first depositing dielectric thin-film layers over the substrate and then performing a backside etching process on a bulk silicon with TMAH or KOH or carrying out a dry plasma etch until the bottom dielectric thin-film layer is exposed. Before backside etching the bulk silicon, rectangular openings are formed on the dielectric thin-film layers by applying a plasma etching to separate the area of heater and sensing elements from the rest of the membrane. This mass flow sensor is operated with two sets of circuits, a first circuit for measuring a flow rate in a first range of flow rates and a second circuit for measuring a flow rate in a second range of flow rates, to significantly increase range of flow rate measurements, while maintains a high degree of measurement accuracy.

Micromachined thermal mass flow sensors and insertion type flow meters and manufacture methods

The present invention discloses an electro-optical device support on a substrate. The electro-optical device includes two face-to-face freestanding membranes each supported near a top surface on one of two bonded substrates for defining a resonant cavity between the two membranes. Each of the substrates having an entire bulk-portion opposite the cavity etched off as a bulk micro-machining opening extended from each of the membranes through a bottom surface of the substrates.

Fabry-Perot cavity manufactured with bulk micro-machining process applied on supporting substrate

The present invention discloses an optical gain equalization system for receiving and equalizing a multiple-channel input optical signal. The optical gain equalization system includes a cascaded array of tunable optical filters filtering the multiple-channel input optical signal and generating a plurality of sub-signals and a residual signal and each of the sub-signals transmitted over a mutually exclusive filter-specific spectrum-range while a combination of all the filter-specific spectrums dynamically covering the spectral portions of said multi-channel input optical signal where power equalizations are required, and all said filter-specific spectrums together with the residual signal spectrum substantially covering an entire spectral range of the multi-channel input optical signal. The gain equalization system further includes a corresponding array of variable optical attenuators (VOAs) each connected to one of a corresponding tunable optical filter for attenuating the sub-signal transmitted over the filter-specific spectrum range for generating an equalized sub-signal. And, the gain equalization system further includes a multiplexing means for receiving and multiplexing the equalized sub-signals generated by the array of variable optical attenuators (VOAs) and the residual signal for generating an equalized output optical signal.

Dynamic gain equalization system design with adaptive spectrum decomposition methodology

The present invention discloses a tunable optical device. The tunable optical device includes a tuning cavity having a tuning means provided for alternately bonding to at least two different tunable optical cells each comprising a tuning membrane wherein the tuning cavity disposed near the tuning membrane for moving the tuning membrane for tuning one of the at least two tunable optical cells bonded thereon. In a preferred embodiment, the tuning cavity further includes a first electrode disposed on the tuning membrane and a second electrode disposed on a substrate supporting the tuning cavity for applying a voltage to move the tuning membrane. In a preferred embodiment, the optical device further includes an optical device control circuit connected to the tuning means for controlling and moving the tuning membrane. In a preferred embodiment, the tuning cavity further includes through hole along an optical path for an optical transmission passing through the tunable membrane for providing an interface-free and ripple-free optical path for the optical transmission. In a preferred embodiment, the tunable optical cells constitute an optical filter for bonding to the tuning cavity and tunable by moving the tunable membrane. In a preferred embodiment, the tunable optical cells constitute an optical attenuator for bonding to the tuning cavity and tunable by moving the tunable membrane. In a preferred embodiment, the tunable optical cells constitute an optical switch for bonding to the tuning cavity and tunable by moving the tunable membrane. In a preferred embodiment, the tunable optical cells constitute an optical dispersion compensator for bonding to the tuning cavity and tunable by moving the tunable membrane. In a preferred embodiment, the optical device constitutes a micro-electro-mechanical system (MEMS) optical device manufactured by applying a micro-electro-mechanical system (MEMS) technology.

Basic common optical cell configuration of dual cavities for optical tunable devices

This invention discloses a configuration of thin-film membrane. This thin-film membrane is freestanding, movable, and made of multiple layers of different materials such as silicon nitride, polycrystalline silicon or the combination of these two. This thin-film membrane can be actuated by external controlling forces such as electrostatic force. This thin-film membrane consists of odd number of layers, e.g., 1 layer, 3 layers, 5 layers, . . . , etc. Moreover, the layer profile of this membrane is symmetric, e.g., the bottommost layer is made to be identical to the topmost layer, the next bottommost layer is made to be identical to the next topmost layer, so on and so forth.

Robust multi-layered thin-film membrane for micro-electromechanical systems (MEMS) photonic devices

The present invention discloses an electro-optical device support on a substrate. The electro-optical device includes a sacrificial layer disposed on the substrate having a chamber-wall region surrounding and defining an optical chamber. The electro-optical device further includes a membrane layer disposed on top of the sacrificial layer having a chamber-removal opening surrounding and defining an electric tunable membrane for transmitting an optical signal therethrough. The electrically tunable membrane disposed on top of the optical chamber surrounded by the chamber wall regions. The chamber-wall region is doped with ion-dopants for maintaining the chamber-wall region for removal-resistance under a chamber-forming process performed through the chamber-removal opening. In a preferred embodiment, the chamber-wall region is a doped silicon dioxide region with carbon or nitrogen. In another preferred embodiment, the chamber-wall region is a nitrogen ion-doped SiNxOy region. In another preferred embodiment, the optical chamber is an etched chamber formed by etching through the chamber removal opening for etching off an etch-enhanced region surrounded by an etch-resistant region constituting the chamber wall.

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San Jose, CA, United States of America

Gaofeng Wang