Inventors list

Assignees list

Classification tree browser

Top 100 Inventors

Top 100 Assignees


Hisashi Yamada

Hisashi Yamada, Ibaraki JP

Patent application numberDescriptionPublished
20110057166NONPOLAR III-NITRIDE LIGHT EMITTING DIODES WITH LONG WAVELENGTH EMISSION - A III-nitride film, grown on an m-plane substrate, includes multiple quantum wells (MQWs) with a barrier thickness of 27.5 nm or greater and a well thickness of 8 nm or greater. An emission wavelength can be controlled by selecting the barrier thickness of the MQWs. Device fabricated using the III-nitride film include nonpolar III-nitride light emitting diodes (LEDs) with a long wavelength emission.03-10-2011

Hisashi Yamada, Chiyoda-Ku JP

Patent application numberDescriptionPublished
20100012626WIRE ELECTRICAL DISCHARGE MACHINING APPARATUS - A wire electrical discharge machining apparatus includes a unit capable of separately opening and closing each of a high impedance path and a low impedance path, a unit that sets an open/close pattern in which a combination of closing one of the feeding paths and opening another one of the feeding paths is designated for switching power feeding between the high impedance path and the low impedance path, a unit that changes pulse energy per feeding pulse in a present feeding path to reduce a difference in discharge pulse energy applied to an inter-electrode gap from a machining power supply between at a time of high-impedance-path feeding and at a time of low-impedance-path feeding, and a unit that controls opening and closing of the path open/close unit in accordance with the changed open/close pattern.01-21-2010
20100084378WIRE ELECTRICAL DISCHARGE MACHINING APPARATUS - A machining-energy calculating unit accumulates a discharge current value for each discharge position to calculate a machining energy in a certain time period from the present time to the past time. An energy-distribution changing unit determines the presence or absence of imbalance in the energy by obtaining a machining energy distribution in an up-down direction of the machining gap based on the machining energy, and when there is imbalance, the energy-distribution changing unit produces a new open/close pattern in which a machining energy distribution that eliminates the imbalance. Power feeding is then performed based on the new open/close pattern.04-08-2010
20100219164FLUID-QUALITY CONTROL METHOD, FLUID-QUALITY CONTROL APPARATUS, AND ELECTRIC-DISCHARGE MACHINING APPARATUS EMPLOYING THE SAME - Target fluid is made into electrolyte solution when measured fluid-quality value is lower than a first condition value, by substituting an impurity anion contained in the target fluid with a predetermined anion and substituting an impurity cation contained in the target fluid with a predetermined cation, and purified when the fluid-quality value is higher than a second condition value. The above procedures are repeated, so that the fluid-quality value of the target fluid falls within a predetermined range, to make the target fluid into electrolyte solution with a correlation between pH and conductivity.09-02-2010
20100224596WIRE ELECTRICAL DISCHARGE MACHINING APPARATUS - In a wire electrical discharge machining apparatus, an upper main-discharge power supply is connected between an upper conducting terminal and a workpiece using an upper main-feeder line capable of configuring outward and homeward paths, and a lower main-discharge power supply is connected between a lower conducting terminal and the workpiece using a lower main-feeder line capable of configuring outward and homeward paths. Moreover, a sub-discharge power supply is connected between the upper conducting terminal and the workpiece and between the lower conducting terminal and the workpiece using an upper and a lower sub-feeder lines that have higher impedances than the impedances of the upper and the lower main-feeder lines and can configure outward and homeward paths.09-09-2010

Hisashi Yamada, Tokyo JP

Patent application numberDescriptionPublished
20090057274ELECTRIC DISCHARGE MACHINE AND ELECTRIC DISCHARGE MACHINING METHOD - In an electric discharge machining apparatus that machines a workpiece (03-05-2009
20090116893Printing Device and Printing Method - A first cutter 05-07-2009
20090277876ELECTRICAL DISCHARGE MACHINING APPARATUS AND ELECTRICAL DISCHARGE MACHINING METHOD - An electrical-discharge machining apparatus for machining a workpiece (11-12-2009
20090314747WIRE ELECTRIC DISCHARGE MACHINE - A wire electric discharge machine includes a wire electrode; a machining power supply that supplies a machining current to between the wire electrode and a workpiece; a first power feed contact and a second power feed contact that respectively feed power to the wire electrode; a first machining-current loop that lets a first machining current to flow from the first power feed contact toward the workpiece; a second machining-current loop that lets a second machining current to flow from the second power feed contact toward the workpiece; an impedance switching circuit that is provided in at least any one of the first machining-current loop and the second machining-current loop; and a control unit that controls a flow ratio of the first machining current and the second machining current by changing an impedance of the impedance switching circuit.12-24-2009
20100133237Wire-Discharge Machining Apparatus - A wire-discharge machining apparatus controls a short circuit between a wire electrode and a workpiece and wire-breakage, and makes it easy to improve productivity, by performing power supply control to mix an upper-side power supply state in which a high-frequency pulse voltage is applied from an upper-side power supplying unit, a lower-side power supply state in which the high-frequency pulse voltage is applied from a lower-side power supplying unit, and a both-sides power supply state in which the high-frequency pulse voltage is applied to the wire electrode from both power supplying units in synchronization with each other during a period of electric discharge machining.06-03-2010

Patent applications by Hisashi Yamada, Tokyo JP

Hisashi Yamada, Yokohama-Shi JP

Patent application numberDescriptionPublished
20080304401INFORMATION RECORDING MEDIUM, INFORMATION RECORDING METHOD, AND INFORMATION REPRODUCING METHOD - According to one embodiment, an optical information recording medium includes pre-grooves with an irregular shape and lands each of which is sandwiched between the pre-grooves adjacent to each other, where the pre-grooves and lands are defined on an interface between a recording layer and a light reflection layer in a recording film, where the recording film includes a light reflectivity that enables reproduction with light of 650±5 nm, the recording layer includes a recording sensitivity with respect to light by a wavelength shorter than 650±5 nm, and a recording mark can be formed on the pre-groove by using light with a wavelength shorter than 650±5 nm.12-11-2008
20090003159OPTICAL DISK APPARATUS AND OPTICAL DISK RECORDING METHOD - According to one embodiment, there is provided an optical disk apparatus including a recording unit which irradiates an optical disk with a laser beam to record information in a first format and a second format, a generation unit which generates warning information to an optical disk apparatus capable of performing a read process in the second format while being not capable of performing the read process in the first format, the warning information warning that information is recorded in the first format in the optical disk, and a control unit which controls the recording unit to record the warning information in the second format in the optical disk apparatus when the information is recorded in the first format in the optical disk.01-01-2009
20090292896INFORMATION MANAGEMENT METHOD, RECORDING/PLAYBACK APPARATUS, AND INFORMATION STORAGE MEDIUM - In an information management method according to an embodiment of the invention, one or more freely installable memory cards are used. A suitable information management can be made even if a part or all of the memory cards is/are optionally attached or detached. Digital AV information of which recording may be distributed over the one or more memory cards is managed according to a prescribed format (which is common to all of the memory cards). Identification information for identifying the card is recorded on each of the memory cards. Allocation information (FAT) indicating where is allocated a portion of the digital AV information is also recorded on each of the memory cards. The allocation information of each of the memory cards identified by the identification information is acquired, and the acquired allocation information is integrated. The acquisition and integration are performed each time the memory card is attached or detached.11-26-2009
20100135436SIGNAL PROCESSING SYSTEM AND INFORMATION STORAGE MEDIUM - According to one embodiment, a first encoder encodes main information, a second encoder encodes sub-information, a first modulator modulates a carrier based on an output of the first encoder, a duplicating module duplicates an output of the second encoder to generate encoded sub-information units, and a second modulator amplitude-modulates an output of the first modulator based on the encoded sub-information units. The second modulator amplitude-modulates with σ/(μ×(206-03-2010

Patent applications by Hisashi Yamada, Yokohama-Shi JP

Hisashi Yamada, Tsukuba JP

Patent application numberDescriptionPublished
20080308907PLANAR NONPOLAR m-PLANE GROUP III NITRIDE FILMS GROWN ON MISCUT SUBSTRATES - A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.12-18-2008
20090039339NONPOLAR III-NITRIDE LIGHT EMITTING DIODES WITH LONG WAVELENGTH EMISSION - A III-nitride film, grown on an m-plane substrate, includes multiple quantum wells (MQWs) with a barrier thickness of 27.5 nm or greater and a well thickness of 8 nm or greater. An emission wavelength can be controlled by selecting the barrier thickness of the MQWs. Device fabricated using the III-nitride film include nonpolar III-nitride light emitting diodes (LEDs) with a long wavelength emission.02-12-2009
20090039356PLANAR NONPOLAR M-PLANE GROUP III-NITRIDE FILMS GROWN ON MISCUT SUBSTRATES - A nonpolar III-nitride film grown on a miscut angle of a substrate. The miscut angle towards the <000-1> direction is 0.75° or greater miscut and less than 27° miscut towards the <000-1> direction. Surface undulations are suppressed and may comprise faceted pyramids. A device fabricated using the film is also disclosed. A nonpolar III-nitride film having a smooth surface morphology fabricated using a method comprising selecting a miscut angle of a substrate upon which the nonpolar III-nitride films are grown in order to suppress surface undulations of the nonpolar III-nitride films. A nonpolar III-nitride-based device grown on a film having a smooth surface morphology grown on a miscut angle of a substrate which the nonpolar III-nitride films are grown. The miscut angle may also be selected to achieve long wavelength light emission from the nonpolar film.02-12-2009
20090194761ENHANCEMENT OF OPTICAL POLARIZATION OF NITRIDE LIGHT-EMITTING DIODES BY INCREASED INDIUM INCORPORATION - An increase in the Indium (In) content in light-emitting layers of light-emitting diode (LED) structures prepared on nonpolar III-nitride substrates result in higher polarization ratios for light emission than LED structures containing lesser In content. Polarization ratios should be higher than 0.7 at wavelengths longer than 470 nm.08-06-2009
20100052008ENHANCEMENT OF OPTICAL POLARIZATION OF NITRIDE LIGHT-EMITTING DIODES BY WAFER OFF-AXIS CUT - An off-axis cut of a nonpolar III-nitride wafer towards a polar (−c) orientation results in higher polarization ratios for light emission than wafers without such off-axis cuts. A 5° angle for an off-axis cut has been confirmed to provide the highest polarization ratio (0.9) than any other examined angles for off-axis cuts between 0 and 27°.03-04-2010

Patent applications by Hisashi Yamada, Tsukuba JP

Hisashi Yamada, Tsukuba-Shi JP

Patent application numberDescriptionPublished
20110227042METHOD FOR PRODUCING SEMICONDUCTOR SUBSTRATE, SEMICONDUCTOR SUBSTRATE, METHOD FOR MANUFACTURING ELECTRONIC DEVICE, AND REACTION APPARATUS - There is provided a method of producing a semiconductor wafer by thermally processing a base water having a portion to be thermally processed that is to be thermally processed. The method comprises a step of providing, on the base wafer, a portion to be heated that generates heat through absorption of an electromagnetic wave and selectively heats the portion to be thermally processed, a step of applying an electromagnetic wave to the base wafer, and a step of lowering the lattice defect density of the portion to he thermally processed, by means of the heat generated by the portion to be heated through the absorption of the electromagnetic wave.09-22-2011
20110227199METHOD FOR PRODUCING SEMICONDUCTOR SUBSTRATE, SEMICONDUCTOR SUBSTRATE, METHOD FOR MANUFACTURING ELECTRONIC DEVICE, AND REACTION APPARATUS - There is provided a method of producing a semiconductor wafer by thermally processing a base wafer having a portion to be thermally processed that has a single-crystal layer and is to be subjected to thermal processing and a portion to be protected that is to be protected from heal, to be added during the thermal processing. The method comprises a step of forming, above the portion to be protected, a protective layer for protecting the portion to be protected from an electromagnetic wave to be applied to the base wafer, and a step of annealing the portion to be thermally processed, by applying the electromagnetic wave to the entire base wafer.09-22-2011