Patents by Inventor Tihiro Ohkawa
Tihiro Ohkawa 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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Patent number: 6139681Abstract: A system and method for removing plasma contaminants from a vacuum vessel requires circulating a fluid through the vacuum vessel and thereby exposing the fluid to the contaminants. When the contaminants contact the fluid, they are trapped and become suspended in the fluid. The contaminants are then removed from the vacuum vessel along with the fluid. Subsequently, the contaminants can be removed from the fluid, and the fluid reintroduced into the vessel for the subsequent removal of additional contaminants. For one embodiment, a cleaning plasma is generated in the vacuum chamber which interacts with the contaminants to create neutrals. The fluid is then circulated through channels that are formed into a tray which is inserted into the bottom of the chamber. The neutrals then fall into the fluid on the tray, while magnetic shields prevent the cleaning plasma itself from doing so. In another embodiment, the vacuum vessel is an open-ended, hollow, cylindrical centrifuge which is tilted from the vertical.Type: GrantFiled: March 9, 1999Date of Patent: October 31, 2000Assignee: Archimedes Technology Group, Inc.Inventor: Tihiro Ohkawa
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Patent number: 6106683Abstract: A device and method for polishing the surface of a substrate uses a vessel for holding a plasma in a magnetic field. Further, the magnetic field is selectively oriented in the vessel relative to the substrate surface. An ion accelerator is then activated to accelerate ions from the plasma on a curved path toward the substrate. By controlling the strength of the magnetic field, and the r-f power and frequency needed to accelerate the ions, the accelerated ions are sent on the curved path for collision with the substrate surface. These collisions, which occur at grazing angles in the range of 0.degree.-20.degree., remove atoms from the substrate surface and thereby polish the surface.Type: GrantFiled: June 23, 1997Date of Patent: August 22, 2000Assignee: Toyo Technologies Inc.Inventor: Tihiro Ohkawa
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Patent number: 6096220Abstract: A plasma mass filter for separating low-mass particles from high-mass particles in a multi-species plasma includes a cylindrical shaped wall which surrounds a hollow chamber. A magnet is mounted on the wall to generate a magnetic field that is aligned substantially parallel to the longitudinal axis of the chamber. Also, an electric field is generated which is substantially perpendicular to the magnetic field and which, together with the magnetic field, creates crossed magnetic and electric fields in the chamber. Importantly, the electric field has a positive potential on the axis relative to the wall which is usually zero potential. When a multi-species plasma is injected into the chamber, the plasma interacts with the crossed magnetic and electric fields to eject high-mass particles into the wall surrounding the chamber. On the other hand, low-mass particles are confined in the chamber during their transit therethrough to separate the low-mass particles from the high-mass particles.Type: GrantFiled: November 16, 1998Date of Patent: August 1, 2000Assignee: Archimedes Technology Group, Inc.Inventor: Tihiro Ohkawa
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Patent number: 6027623Abstract: A device for fractionating macromolecules in a fluid medium includes a plurality of individual obstacles which are arranged on a substrate in rows and columns. An electric field is provided and oriented to move the macromolecules in migration through fluid channels that are established between the columns of obstacles. Each obstacle has mutually symmetrical right and left front walls which are inclined to a respective fluid channel. Consequently, as macromolecules diffuse through the fluid medium from a fluid channel during their migration through the device, the front walls of the obstacles redirect them back into the same fluid channel from which they diffused. As a result, the faster diffusing, smaller macromolecules take longer to migrate through the fluid channels of the device. Eventually, because the diffusion rate of the macromolecules depends on their size, the positions of the macromolecules in the device reflect their respective diffusion rates, and therefore their size.Type: GrantFiled: April 22, 1998Date of Patent: February 22, 2000Assignee: Toyo Technologies, Inc.Inventor: Tihiro Ohkawa
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Patent number: 6014203Abstract: A digital electron lithography system includes a plurality of cathodes oriented in a plane and positioned substantially parallel to a substrate surface in a vacuum chamber. The substrate surface is coated with a layer of an electron resist material and, in operation, individual cathodes in the array are selectively activated to emit electrons which alter the resist material. In order to create a predetermined pattern on the substrate, a focusing magnet is provided to direct the electrons from the respective cathodes to be focused on the substrate surface along substantially parallel electron paths. Additionally, a steering magnet is provided to change electron path directions so that electrons are steered to sequentially affect a plurality of pixels in a pixel matrix on the substrate surface. To minimize ion damage to the cathodes the electron paths are oriented at an angle to the perpendicular direction between the plane of the array and the substrate surface.Type: GrantFiled: January 27, 1998Date of Patent: January 11, 2000Assignee: Toyo Technologies, Inc.Inventor: Tihiro Ohkawa
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Patent number: 5993678Abstract: A device, and a method for using the device, for altering the surface of a substrate with a plasma includes a vessel having a chamber, a magnet and a plasma generator. Both the generator and the magnet are positioned outside the vessel while the substrate to be altered is placed in the chamber. The magnetic field is established substantially parallel to the substrate surface that is to be altered to insulate the plasma from the substrate surface. Also, a radio frequency wave is propagated from the generator into the chamber to generate the plasma in chamber which alters the surface. Specifically, the plasma is generated in ionization zones located between the substrate surface and the vessel walls. A region in the chamber is thus defined between the ionization zones where the plasma is established with substantially uniform density. Additionally, electrodes can be placed to voltage bias directly or capacitively the plasma for ion etching or deposition on the substrate surface.Type: GrantFiled: July 31, 1996Date of Patent: November 30, 1999Assignee: Toyo Technologies Inc.Inventor: Tihiro Ohkawa
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Patent number: 5939029Abstract: A method and system for separating radioactive waste containing volatiles, into light ions and heavy ions, includes a loader/transporter for transferring the waste into a high vacuum environment in the chamber of a plasma processor. During this transfer, gases of the volatiles are released from the waste, collected in a holding tank, and subsequently ionized in the chamber. As the volatiles are ionized, the ions are directed by a magnetic field into contact with the waste to vaporize the waste. The waste vapors are then ionized in the plasma processor chamber to create a multi-species plasma which includes electrons, light ions and heavy ions. Within the chamber, the density of the multi-species plasma is established to be above its collision density in order to establish a substantially uniform velocity for all ions in the plasma. A nozzle accelerates the multi-species plasma to generate a fluid stream which is directed from the chamber toward an inertial separator.Type: GrantFiled: November 14, 1997Date of Patent: August 17, 1999Assignee: Archimedes Technology Group, Inc.Inventor: Tihiro Ohkawa
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Patent number: 5868897Abstract: A device, and a method for using the device, for altering the surface of a substrate with a plasma includes a vessel having a chamber, a magnet and a plasma generator. Both the generator and the magnet are positioned outside the vessel while the substrate to be altered is placed in the chamber. The magnetic field is established substantially parallel to the substrate surface that is to be altered to insulate the plasma from the substrate surface. Also, a radio frequency wave is propagated from the generator into the chamber to generate the plasma in chamber which alters the surface. Specifically, the plasma is generated in ionization zones located between the substrate surface and the vessel walls. A region in the chamber is thus defined between the ionization zones where the plasma is established with substantially uniform density. Additionally, electrodes can be placed to voltage bias directly or capacitively the plasma for ion etching or deposition on the substrate surface.Type: GrantFiled: September 18, 1996Date of Patent: February 9, 1999Assignee: Toyo Technologies, Inc.Inventor: Tihiro Ohkawa
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Patent number: 5763017Abstract: A method for manufacturing a micro-bubble textured material includes performing simultaneous implantation of inert gas atoms and plasma assisted chemical vapor deposition. Plasma that contains ions of an inert gas and neutrals necessary for PCVD is produced over a substrate. The substrate being deposited with the material to be textured is then biased with a negative voltage to accelerate the ions from the plasma. Control over the bias voltage determines the penetration depth into the materials and control over the ion current to the substrate determines the fractional atomic density of the implanted gas atoms and the penetration depth. Simultaneous deposition causes the location of the layer of the implanted atoms to move at the deposition rate, resulting in a uniform implantation of the atoms.Type: GrantFiled: October 28, 1996Date of Patent: June 9, 1998Assignee: Toyo Technologies Inc.Inventor: Tihiro Ohkawa
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Patent number: 5486337Abstract: A method and apparatus are disclosed for manipulation of very small droplets of liquid, by placing the droplets on wettable positioning electrodes on a non-wettable substrate, applying voltages to the positioning electrodes to electrostatically charge the droplets, and applying voltages of opposite polarity to target electrodes, thereby attracting the droplets from the positioning electrodes toward the target electrodes. The electrodes can be on a manipulation surface or on a separate portable dispensing tool or pickup tool.Type: GrantFiled: February 18, 1994Date of Patent: January 23, 1996Assignee: General AtomicsInventor: Tihiro Ohkawa
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Patent number: 5468358Abstract: Methods for making fiber-reinforced carbon, ceramic or metal matrix composites using electrophoretic infiltration of an array or preform of electrically insulating fibers positioned adjacent a target electrode in an appropriate liquid slurry. The slurry contains a dispersion of micron- or submicron-sized particles, usually of elemental or ceramic materials, which are suitably electrically charged in the slurry, employing a surfactant if necessary. Application of an appropriate voltage causes charged particles to migrate toward the target electrode following a path that causes them to infiltrate the interstices of the fiber array which is usually formed of woven or aligned tows of minute fibers about 5 to 15 microns in diameter. The particles initially deposit on the electrode with subsequent particles aggregating on top of those particles, the process continuing to form a growth front of deposited material growing away from the electrode surface.Type: GrantFiled: July 6, 1993Date of Patent: November 21, 1995Assignee: General AtomicsInventors: Tihiro Ohkawa, Frederick H. Elsner
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Patent number: 5419877Abstract: High temperature gas emissions from industrial power plant or environmental clean-up processes are subjected to an acoustic waveform having second harmonic content and appropriate second harmonic phase shift to impart a net acoustic Oseen force on particulate matter contained in the gas for removal of said matter. Particulate matter of 1 micron radius is positively excluded, while smaller particles are agglomerated by the sound wave. The acoustic waveform further enhances both sorption of injected sorbent particles for removal of sulfur oxides, and the efficiency of an in-line catalytic converter for removal of nitrogen oxides. The invention improves overall removal efficiency, can operate at very high temperatures, and does not produce any secondary waste, such as filters.Type: GrantFiled: September 17, 1993Date of Patent: May 30, 1995Assignee: General AtomicsInventors: Robert R. Goforth, Tihiro Ohkawa
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Patent number: 5405533Abstract: A system and method for inducing flow of a dense gas through a fluid circuit without the use of a compressor or other pumping means. A heat absorption chamber has an outlet in fluid communication with the inlet of a heat rejection chamber and has an inlet in fluid communication with an outlet from the heat rejection chamber. Thermal energy absorbed by the dense gas in the heat absorption chamber causes the density of the dense gas to decrease sufficiently to cause the dense gas to flow to the heat rejection chamber. After heat energy is subsequently rejected from the heated dense gas, its density increases, and gravitational or radial acceleration forces acting thereupon induce the cooled, dense gas to flow to the heat absorption chamber displacing the dense gas therewithin. The fluid flow system of the present invention may be used for heat transfer or may be applied to processes such as solvent extraction, reduction of particle size, and oxidation of organic materials employing supercritical water.Type: GrantFiled: April 7, 1993Date of Patent: April 11, 1995Assignee: General AtomicsInventors: David A. Hazlebeck, Tihiro Ohkawa
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Patent number: 5361016Abstract: A long plasma formation tube is imbedded in a high magnetic field, with magnetic field lines passing axially through the tube, and with the tube being placed proximate or inside of a resonant cavity. Electromagnetic energy resonates in the resonant cavity representing stored microwave energy. The power density of the stored microwave energy is a function of the cross-sectional area of the resonant cavity. A portion of the stored microwave energy is concentrated to increase its power density, and coupled into the plasma formation tube, which tube has a smaller cross-sectional area than the resonant cavity. The coupled energy excites a whistler wave in the plasma formation tube that forms the plasma within the tube. In one embodiment, the stored microwave power is concentrated by funneling it through a metallic iris that forms one end of the resonant cavity, with a tip of the plasma formation tube being positioned near the metallic iris.Type: GrantFiled: January 28, 1993Date of Patent: November 1, 1994Assignee: General AtomicsInventors: Tihiro Ohkawa, Stanley I. Tsunoda, Robert L. Miller
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Plasma processing apparatus for controlling plasma constituents using neutral and plasma sound waves
Patent number: 5350454Abstract: A neutral or plasma sound wave is launched into a plasma used within a plasma processing chamber in order to selectively control the location and concentration of plasma constituents, including (1) contaminants; (2) reactants, including ions or molecules; and/or (3) reaction products. The plasma sound wave comprises a periodic waveform controlled to include at least a second harmonic component. Oseen or Oseen-like forces associated with a neutral or plasma sound wave impart a drift velocity to contaminant particles, e.g., micron-sized dust particles, that moves such particles in a desired direction, e.g., away from a wafer or other work surface being processed by the plasma. An analogous Oseen or Oseen-like force associated with a plasma sound wave imparts a drift velocity to the reactants or reaction products in the plasma so as to move such atomic-sized reactants or products in a desired direction, e.g.Type: GrantFiled: February 26, 1993Date of Patent: September 27, 1994Assignee: General AtomicsInventor: Tihiro Ohkawa -
Patent number: 5308751Abstract: A method for simultaneously sequencing both strands of a target DNA is provided. The method involves "shifting" one or both strands of the target DNA by addition or deletion of one or more nucleotides to one or both strands of the duplex to produce shifted DNA. Both strands of the shifted DNA duplex and the target DNA are sequenced and the sequences of the shifted and unshifted target DNA are compared. Since portions of the sequenced strands of the target and shifted DNA are identical, all or a portion of sequence of the target DNA can be determined.Type: GrantFiled: March 23, 1992Date of Patent: May 3, 1994Assignee: General AtomicsInventors: Tihiro Ohkawa, Robert L. Miller
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Patent number: 5301362Abstract: Generation of a high power rf pulse is achieved in a simple transmitting device that uses permanent magnet material(s) to store energy. Such energy is released through the thermal quenching of the magnetic material(s). Thermal quenching is accomplished, e.g., through an explosion. Such thermal quenching is facilitated in one embodiment by using a magnetic composite material comprising both magnetic particles and explosive particles. The rf pulse thus generated may be used for any desired purpose, e.g., tracking or research. The transmitting device includes a permanent magnet for establishing a constant magnetic flux for so long as the magnet retains its normal magnetic properties. The magnetic flux passes through a coil. Upon the thermal quenching of the magnetic material(s), the magnetic properties rapidly change, causing the magnetic flux to also rapidly change, thus inducing a high power electrical pulse in the coil.Type: GrantFiled: May 6, 1991Date of Patent: April 5, 1994Assignee: General AtomicsInventor: Tihiro Ohkawa
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Patent number: 5225740Abstract: High density plasma is produced in a long cylindrical cavity by the excitation of a high frequency whistler wave within the cavity. The cylindrical cavity, and hence the plasma, is imbedded in a high magnetic field, with magnetic lines of force passing axially (longitudinally) through the cavity. The magnetic field has an electron cyclotron frequency associated therewith that is much greater than the wave frequency associated with the whistler wave. In one embodiment, electromagnetic energy is coupled axially into the cylindrical cavity using a resonant cavity, which coupled energy excites the whistler wave. In another embodiment, electromagnetic energy is coupled radially into the cylindrical cavity using a slow wave structure. The plasma is created without using electrodes; and the excitation of the whistler wave is achieved at a high Q value.Type: GrantFiled: March 26, 1992Date of Patent: July 6, 1993Assignee: General AtomicsInventor: Tihiro Ohkawa
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Patent number: 5194291Abstract: Corona discharge treatment apparatus for treating or coating a surface of a conductive substrate includes a high voltage radio frequency power supply and a cable having a number of flexible conductors and other components. The cable has a first end connected to the power supply and a second end wherein the other cable components have been removed and the conductors extend from the remainder of the cable. The free ends of the conductors at the second end are disposed in a general non-parallel arrangement and the free end of each conductor is held in a separate insulator which extends beyond the free end it holds. Each free end is movable independently of the other free ends. The conductive substrate is held beneath the cable second end so that the upper surface is engaged by the insulators.Type: GrantFiled: April 22, 1991Date of Patent: March 16, 1993Assignee: General AtomicsInventors: James R. D'Aoust, Tihiro Ohkawa
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Patent number: 5149681Abstract: A pre-existing superconductor ceramic which is bonded to a substrate is passed through a relatively short heating zone to melt the ceramic superconductor. As the superconductor is subsequently cooled after it has passed through the heating zone, a temperature gradient is established along the superconductor which causes the melted crystals to renucleate and grow along and parallel to the temperature gradient. The resulting crystalline structure exhibits improved superconducting properties when the superconductor is placed in the presence of a magnetic field. For appropriate applications, the substrate can be formed as a wire.Type: GrantFiled: May 14, 1990Date of Patent: September 22, 1992Assignee: General AtomicsInventors: Tihiro Ohkawa, Richard B. Stephens, Albert J. Lieber