Patents by Inventor Xiang Zheng Tu
Xiang Zheng Tu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20150097260Abstract: A single silicon wafer micromachined thermal conduction sensor is described. The sensor consists of a heat transfer cavity with a flat bottom and an arbitrary plane shape, which is created in a silicon substrate. A heated resistor with a temperature dependence resistance is deposed on a thin film bridge, which is the top of the cavity. A heat sink is the flat bottom of the cavity and parallel to the bridge completely. The heat transfer from the heated resistor to the heat sink is modulated by the change of the thermal conductivity of the gas or gas mixture filled in the cavity. This change can be measured to determine the composition concentration of the gas mixture or the pressure of the air in a vacuum system.Type: ApplicationFiled: October 3, 2013Publication date: April 9, 2015Inventor: Xiang Zheng Tu
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Publication number: 20140069185Abstract: A vacuum-cavity-insulated flow sensor and related fabrication method are described. The sensor comprises a porous silicon wall with numerous vacuum-pores which is created in a silicon substrate, a porous silicon membrane with numerous vacuum-pores which is surrounded and supported by the porous silicon wall, and a cavity with a vacuum-space which is disposed beneath the porous silicon membrane and surrounded by the porous silicon wall. The fabrication method includes porous silicon formation and silicon polishing in HF solution.Type: ApplicationFiled: September 7, 2012Publication date: March 13, 2014Inventor: Xiang Zheng Tu
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Publication number: 20090152663Abstract: A perforated monocrystalline silicon plate assembly is provided for forming and transferring of monocrystalline silicon thin film solar cells. The assembly comprises a perforated monocrystalline silicon plate with a plurality of through holes and obstructive holes. The assembly is allowed to grow a first p-type epitaxial layer with an inverted pyramid surface on the surface of the silicon plate, which is then selectively converted into a porous silicon layer with an inverted pyramid surface. The assembly is further allowed to grow a second p-type epitaxial layer with an inverted pyramid surface on the surface of the porous silicon layer, which is then used to fabricate a monocrystalline silicon thin film solar cell with an inverted pyramid surface.Type: ApplicationFiled: December 18, 2007Publication date: June 18, 2009Inventor: Xiang Zheng Tu
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Patent number: 6836678Abstract: A micro-optical-mechanical-electro-system (MOMES)-based non-invasive blood glucose monitor comprises a micromachined infrared optical filter array, a micromachined infrared mechanical modulator array, at least one micromachined infrared tunable filter, and at least one infrared detector. Each optical filter is aligned with a mechanical modulator along its optical axis direction. The optical filter continuously divides a monochromatic infrared light in a wavelength range within 0.8 to 25 micron from an infrared light. The aligned mechanical modulator turns the monochromatic infrared light into an alternating monochromatic infrared light. The tunable filter is aligned with the infrared detector along its optical axis direction. The tunable filter selects the back-diffused alternating monochromatic infrared light emitted from a measured blood subject that is illuminated by the alternating monochromatic infrared light.Type: GrantFiled: February 13, 2003Date of Patent: December 28, 2004Inventor: Xiang Zheng Tu
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Patent number: 6809753Abstract: An optical microswitch printer head comprising a micromachined optical microswitch array with optical microswitches extending in a main scanning direction. The optical microswitch is based on a variable air gap Fabry-Perot cavity that is defined by two non-absorbing distributed Bragg reflectors. One of the distributed Bragg reflectors is supported by flexible beams so that the length of the Fabry-Perot cavities can be set to be equal to an odd or even multiple of a quarter wavelength of a working optical wave by applying a voltage. As a result, the optical microswitches can be pushed into a transmission state or “on” state for letting a light pass through or a reflection state or “off” state for blocking the light. The optical microswitch printer head can utilize a gas discharge lamp such as a cold cathode fluorescent lamp as a light source.Type: GrantFiled: October 25, 2002Date of Patent: October 26, 2004Inventor: Xiang Zheng Tu
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Publication number: 20040162470Abstract: A micro-optical-mechanical-electro-system (MOMES)-based non-invasive blood glucose monitor comprises a micromachined infrared spectrometer array, a micromachined infrared mechanical modulator array, at least one micromachined infrared tunable filter, and at least one infrared detector. Each spectrometer is aligned with a mechanical modulator along its optical axis direction. The spectrometer continuously divides a monochromatic infrared light in a wavelength range within 0.8 to 25 micron from an infrared light. The aligned mechanical modulator turns the monochromatic infrared light into an alternating monochromatic infrared light. The tunable filter is aligned with the infrared detector along its optical axis direction. The tunable filter selects the back-diffused alternating monochromatic infrared light emitted from a measured blood subject that is illuminated by the alternating monochromatic infrared light.Type: ApplicationFiled: February 13, 2003Publication date: August 19, 2004Inventor: Xiang Zheng Tu
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Patent number: 6773942Abstract: A method for fabricating an optical switch array comprising the steps: providing a two side polished lightly dope (110) silicon substrate; forming a heavily doped layer with a same type impurity as the (110) silicon substrate on the back side of the (110) silicon substrate; growing a lightly doped epitaxial layer on the back side of the (110) silicon substrate; converting the heavily dope layer into a porous silicon layer by anodization in HF solution; forming a plurality of microchannels on the front side of the (110) silicon substrate so that each makes a 135 or 45 degree angle to a (111) crystal plane vertical to the surface of the (110) silicon substrate; converting the porous silicon layer into an oxidized porous silicon layer by thermal oxidization; forming electrical interconnections on the front side of the (110) silicon substrate; forming a plurality of (111) silicon planar plates each having two opposite sides made of (111) silicon crystal planes on the front side of the (110) silicon substrate by aType: GrantFiled: June 19, 2003Date of Patent: August 10, 2004Inventor: Xiang Zheng Tu
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Patent number: 6736982Abstract: A micromachined vertical vibrating gyroscope consists of three single crystal silicon assemblies: an outer single crystal silicon assembly, an intermediate single crystal silicon assembly, and an inner single crystal silicon assembly. The outer assembly includes a plurality of arc-shaped anchors arranged in a circle and extending from a single crystal silicon substrate coated with an insulating annulus thereon. The intermediate assembly is a suspended wheel concentric with the arc-shaped anchors. The inner assembly is a suspended hub concentric with the circle formed by the anchors and having no axle at its center. The three assemblies are connected to each other through several flexures. The intermediate suspended wheel is driven into rotational vibration by lateral comb capacitors. Input angular rates are measured by two vertical capacitors.Type: GrantFiled: June 15, 2001Date of Patent: May 18, 2004Inventor: Xiang Zheng Tu
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Patent number: 6731831Abstract: An optical switch array assembly for DNA probe light synthesis and hybridized DNA probe light detection is composed of a silicon substrate, an optical switch array disposed in the substrate, a glass plate mounted on the top of the substrate, and a DNA probe array disposed on the surface of the glass plate. The substrate also contains a driving circuit for forcing each optical switch on and off and an addressing circuit for locating each optical switch. A plurality of holes is disposed in the substrate so that each hole is aligned with an optical switch and guides a light beam to a corresponding optical switch.Type: GrantFiled: February 27, 2002Date of Patent: May 4, 2004Inventor: Xiang Zheng Tu
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Publication number: 20040081498Abstract: An optical microswitch printer head comprising a micromachined optical microswitch array with optical microswitches extending in a main scanning direction. The optical microswitch is based on a variable air gap Fabry-Perot cavity that is defined by two non-absorbing distributed Bragg reflectors. One of the distributed Bragg reflectors is supported by flexible beams so that the length of the Fabry-Perot cavities can be set to be equal to an odd or even multiple of a quarter wavelength of a working optical wave by applying a voltage. As a result, the optical microswitches can be pushed into a transmission state or “on” state for letting a light pass through or a reflection state or “off” state for blocking the light. The optical microswitch printer head can utilize a gas discharge lamp such as a cold cathode fluorescent lamp as a light source.Type: ApplicationFiled: October 25, 2002Publication date: April 29, 2004Inventor: Xiang Zheng Tu
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Publication number: 20030210854Abstract: An optical switch array comprises a (110) silicon substrate integrating a plurality of (111) silicon planar plates, a plurality of flexural silicon strips and a plurality of microchannels therein. The (111) silicon planar plates are coated with a reflective layer on both opposite surfaces and are used as double-sided mirrors. Each silicon strip vertically supports a (111) silicon planar plate and can be electrically bent up to lift the (111) silicon planar plates out of the (110) silicon substrate. The microchannels are oriented to a (111) silicon planar plate at a 135 or 45 degree angle. Each microchannel holds an optical fiber or a cylindrical lens therein. A passive alignment can be realized between the optical fibers, the cylindrical lenses and the (110) silicon planar plates.Type: ApplicationFiled: June 19, 2003Publication date: November 13, 2003Inventor: Xiang Zheng Tu
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Patent number: 6622373Abstract: A method for manufacturing a thermal ink jet print head with high efficiency of heat transfer is disclosed. The heating resistors of the head are made of doped single crystalline silicon. Each resistor is disposed in a silicon stripe that is surrounded by a thermal insulating material filled trench and forms a top cover of a corresponding microchannel. The head generated by the resistor can only flow into the ink disposed in the microchannel. The microchannels and nozzles of the head are constructed in a single crystalline silicon substrate. The head is fabricated based on a porous silicon process including: (1) converting heavily doped single crystal silicon into porous silicon; (2) turning porous silicon into oxidized porous silicon; (3) using oxidized porous silicon as a stop barrier for anisotropic etching of single crystal silicon; and (4) selective etching of oxidized porous silicon.Type: GrantFiled: August 28, 2000Date of Patent: September 23, 2003Inventor: Xiang Zheng Tu
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Publication number: 20030161575Abstract: An optical switch array assembly for DNA probe light synthesis and hybridized DNA probe light detection is composed of a silicon substrate, an optical switch array disposed in the substrate, a glass plate mounted on the top of the substrate, and a DNA probe array disposed on the surface of the glass plate. The substrate also contains a driving circuit for forcing each optical switch on and off and an addressing circuit for locating each optical switch. A plurality of holes is disposed in the substrate so that each hole is aligned with an optical switch and guides a light beam to a corresponding optical switch.Type: ApplicationFiled: February 27, 2002Publication date: August 28, 2003Inventor: Xiang Zheng Tu
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Patent number: 6602427Abstract: A method for fabricating a micromachined optical mechanical modulator based WDM transmitter/receiver module is described. The Fabry-Perot cavity of the mechanical modulator is structured from a three-polysilicon-layer stack formed on the surface of a single crystalline silicon substrate. The polysilicon membrane and its supporting polysilicon beams of the cavity are cut from the top polysilicon layer of the stack and are released by selective etching of their underlying polysilicon. The etched underlying polysilicon layer is heavily doped and then converted into porous polysilicon by anodization in HF solution. The polysilicon membrane and its supporting polysilicon are finally released using a reactive ion etch process to avoid stiction often generated in a wet etch process. A conic hole is formed on the backside of the single crystalline silicon substrate for receiving an optical fiber that can be passively aligned with the Fabry-Perot cavity.Type: GrantFiled: August 28, 2000Date of Patent: August 5, 2003Inventor: Xiang Zheng Tu
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Publication number: 20020189350Abstract: A micromachined vertical vibrating gyroscope consists of three single crystal silicon assemblies: an outer single crystal silicon assembly, an intermediate single crystal silicon assembly, and an inner single crystal silicon assembly. The outer assembly includes a plurality of arc-shaped anchors arranged in a circle and extending from a single crystal silicon substrate coated with an insulating annulus thereon. The intermediate assembly is a suspended wheel concentric with the arc-shaped anchors. The inner assembly is a suspended hub concentric with the circle formed by the anchors and having no axle at its center. The three assemblies are connected to each other through several flexures. The intermediate suspended wheel is driven into rotational vibration by lateral comb capacitors. Input angular rates are measured by two vertical capacitors.Type: ApplicationFiled: June 15, 2001Publication date: December 19, 2002Inventor: Xiang Zheng Tu
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Patent number: 6359276Abstract: A microbolometer infrared sensor utilizes a porous silicon bridge as its thermal isolating and mechanical supporting structure. Porous silicon formed from single crystal silicon on lightly doped p-type silicon has a thermal conductivity lower than silicon dioxide and silicon nitride, and, therefore, when used as a mechanical supporting structure, can offer better thermal isolation performance. The porous silicon layer can be fabricated much thicker than silicon dioxide and silicon nitride membranes since there is almost no residual stress therein. A thicker porous silicon bridge has higher mechanical support strength. The porous silicon process is a low temperature process. It facilitates a fabrication strategy of microelectronics first and micromechanics last.Type: GrantFiled: July 6, 1999Date of Patent: March 19, 2002Inventor: Xiang Zheng Tu
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Patent number: 6219470Abstract: A wavelength division multiplexing transmitter and receiver module utilizes a micromachined silicon substrate as the mounting platform for its optical components and optoelectronic devices including an optical fiber, a transmitter, two receivers, and three microlenses. The micromachined silicon substrate has a V-groove for placing an optical fiber so that it is aligned with the mounted transmitter and the mounted receivers passively and has more V-grooves with slanted end side walls and opposite vertical end side walls used to form a dielectric multilayered filter, a half-mirror, and two anti-reflectors thereon which are eventually incorporated to be a multiplexer and/or a demultiplexer. The microlenses are disposed on V-supports. The transmitter is pre-mounted mounted on a V-submount. The microlens and the transmitter are then mounted into the V-grooves of the micromachined silicon substrate and aligned with the mounted optical fiber passively.Type: GrantFiled: September 23, 1999Date of Patent: April 17, 2001Inventor: Xiang Zheng Tu
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Patent number: 5381231Abstract: Fiber optic interferometric sensors and methods of manufacturing same are disclosed. These sensors comprise a unitary substrate having a channel therein and an axis extending through the channel. The unitary substrate also comprises a reflective surface extending in a plane perpendicular to the axis. An optical fiber having a terminated surface thereon is also provided. The optical fiber extends axially within the channel and is arranged so that the terminated surface and the reflective surface are movable relative to one another in response to a phenomenon to be sensed. The unitary substrate also comprises positioning means integral therewith for positioning the optical fiber within the channel. The method of manufacturing the fiber optic interferometric sensors comprise the steps of providing a unitary substrate and forming a channel therein so that an axis extends therethrough.Type: GrantFiled: January 7, 1993Date of Patent: January 10, 1995Assignee: Ameron Technologies, Inc.Inventor: Xiang-Zheng Tu
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Patent number: 5352635Abstract: A silicon accelerometer comprising a substrate, one or more pairs of beams, a pedestal, a mass on top of the pedestal and a cavity beneath the pedestal all of which is formed by a single-sided processing method. The pedestal is suspended over the cavity by the beams which provides the only support for the pedestal. The beams are supported by the substrate. The main steps of fabricating this structure comprise diffusion or ion implantation and epitaxial growth to form a buried high donor concentration layer on the surface of the substrate, chemical vapor deposition and photoetching to expose a portion of the edge of the buried layer to the ambiente, anodization to convert the high donor concentration layer into porous silicon and selectively etching to remove the porous silicon.Type: GrantFiled: January 28, 1993Date of Patent: October 4, 1994Inventors: Xiang-Zheng Tu, Yun-Yan Li