Patents by Inventor Akira Usui
Akira Usui 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: 20070019831Abstract: In an array speaker system that performs multi-channel reproduction using an array speaker constituted by arraying a plurality of speaker units in a matrix manner, a left channel signal, a right channel signal, and a center channel signal, all of which instruct reproduction of sound at a front side of a listener, are subjected to weighting using weight coefficients based on a Bessel function so as to drive the speaker units, thus realizing spherical sound emission characteristics. In addition, a surround left channel signal and a surround right channel signal, both of which instruct reproduction of sound at a rear side of the listener, are subjected to beam processing, whereby sound is reflected on a sound reflection position such as a wall surface or a ceiling and is then emitted in the form of a sound beam reaching the rear side of the listener.Type: ApplicationFiled: June 1, 2004Publication date: January 25, 2007Applicant: Yamaha CorporationInventor: Akira Usui
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Publication number: 20060256979Abstract: An array speaker system is constituted by a plurality of speaker units, which are equipped with weighting means respectively and to which weight coefficients based on a Bessel function are imparted. An input signal is transmitted through an all-pass filter whose phase rotates by 180° in high-frequency ranges and is then supplied to those of the speaker units whose weight coefficients have negative values. Thus, a signal of an inverse phase is output with respect to low-frequency ranges; hence, it is possible to avoid the deterioration of audio emission characteristics, and it is possible to avoid the occurrence of beams and comb shapes in audio emission characteristics with respect to signals of high-frequency ranges.Type: ApplicationFiled: May 6, 2004Publication date: November 16, 2006Applicant: Yamaha CorporationInventors: Akira Usui, Masao Noro
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Publication number: 20060191467Abstract: To provide a semiconductor substrate of a group III nitride with a little warp, this invention provides a process comprising such steps of: epitaxial-growing a GaN layer 33 with a GaN low temperature grown buffer layer 32 upon a sapphire substrate 31; removing the sapphire substrate 31, the GaN buffer layer 32 and a small portion of the GaN layer 33 from the substrate taken out of a growth reactor to obtain a self-supporting GaN substrate 35; and after that, heat-treating the GaN substrate 35 by putting it into an electric furnace under the NH3 atmosphere at: 1200° C. for 24 hours; which leads to a marked reduction of the warp of the self-supporting GaN substrate 35 such that dislocation densities of its obverse and reverse surface are 4×107 cm?2 and 8×105 cm?2, and thereby such a low ratio of dislocation densities of 50 is well-controlled.Type: ApplicationFiled: May 8, 2006Publication date: August 31, 2006Inventors: Akira Usui, Masatomo Shibata, Yuichi Oshima
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Publication number: 20060193237Abstract: A system and method of drawing a visible image on an optical disk are provided. The optical disk is rotated while a optical pickup irradiates a laser beam onto the optical disk to draw the visible image on the optical disk. The rotating state of the optical disk is detected. The optical pickup is fed in a radial direction of the optical disk. An irradiating position of the laser beam is controlled relative to the optical disk by fixing the laser beam in the radial direction of the optical disk during one rotation of the optical disk, and shifting the irradiating position of the laser beam by a first distance in the radial direction each time one rotation of the optical disk is detected. The optical pickup is fed in the radial direction by a second distance the optical disk has rotated a predetermined number of rotations.Type: ApplicationFiled: April 14, 2006Publication date: August 31, 2006Applicant: Yamaha CorporationInventors: Morito Morishima, Akira Usui, Yoshihiko Shiozaki
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Patent number: 7097920Abstract: To provide a semiconductor substrate of a group III nitride with a little warp, this invention provides a process comprising such steps of: epitaxial-growing a GaN layer 33 with a GaN low temperature grown buffer layer 32 upon a sapphire substrate 31; removing the sapphire substrate 31, the GaN buffer layer 32 and a small portion of the GaN layer 33 from the substrate taken out of a growth reactor to obtain a self-supporting GaN substrate 35; and after that, heat-treating the GaN substrate 35 by putting it into an electric furnace under the NH3 atmosphere at 1200° C. for 24 hours; which leads to a marked reduction of the warp of the self-supporting GaN substrate 35 such that dislocation densities of its obverse and reverse surface are 4×107 cm?2 and 8×105 cm?2, and thereby such a low ratio of dislocation densities of 50 is well-controlled.Type: GrantFiled: March 24, 2003Date of Patent: August 29, 2006Assignees: NEC Corporation, Hitachi Cable, Ltd.Inventors: Akira Usui, Masatomo Shibata, Yuichi Oshima
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Patent number: 7082094Abstract: An optical disk apparatus records information by irradiating a laser beam from a pickup onto an optical disk. A scanning section scans the laser beam relative to the optical disk. A recording control section controls the scanning section to effect recording of information. A drawing control section is provided for controlling the pickup and the scanning section to effect drawing of a visible image on the optical disk according to image information, such that the laser beam is changed between a first intensity incapable of acting on the optical disk and a second intensity capable of acting on the optical disk. A servo section periodically detects the laser beam reflected back from the optical disk when the laser beam has the first intensity, and servo-controls the irradiating of the laser beam during the drawing of the visible image based on the detection of the laser beam.Type: GrantFiled: October 29, 2002Date of Patent: July 25, 2006Assignee: Yamaha CorporationInventors: Morito Morishima, Akira Usui, Yoshihiko Shiozaki
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Publication number: 20060126878Abstract: A multi-channel audio system is constituted using at least one line array speaker unit, in which plural speakers are arrayed in line, wherein the same audio signal is supplied with a prescribed delay time to each of the speakers, thus forming plural sound beams. The plural sound beams are reflected on a wall surface and a ceiling of a room so as to form plural virtual sound sources surrounding a listening position, and emission directions and intensities of the sound beams are controlled so as to localize a phantom at a prescribed position based on the plural virtual sound sources. By appropriately arranging plural line array speaker units horizontally, vertically, and slantingly in such a way that each line array speaker unit forms sound beams distributed and spread in a sectorial form, it is possible to realize a surround audio system having a high degree of freedom with regard to setup positions for forming virtual sound sources.Type: ApplicationFiled: February 6, 2006Publication date: June 15, 2006Applicant: Yamaha CorporationInventors: Susumu Takumai, Akira Usui
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Patent number: 7046597Abstract: A method is designed for recording contents information along a track of an optical disk of a writeable type. A volume detection step is carried out for detecting an actual volume of the contents information to be recorded into the optical disk. A capacity detection step is carried out for detecting a nominal capacity of the optical disk, which indicates a rated volume of information to be recorded at maximum. A density determination step is carried out for determining a recording density of the contents information based on the detected actual volume and the detected nominal capacity. A record step is carried out for recording the contents information into the optical disk at the determined recording density such that the actual volume of the contents information can fit into the nominal capacity of the optical disk.Type: GrantFiled: July 29, 2002Date of Patent: May 16, 2006Assignee: Yamaha CorporationInventors: Akira Usui, Yukihisa Nakajo
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Publication number: 20060077821Abstract: A method is designed for recording contents information along a track of an optical disk of a writeable type. A volume detection step is carried out for detecting an actual volume of the contents information to be recorded into the optical disk. A capacity detection step is carried out for detecting a nominal capacity of the optical disk, which indicates a rated volume of information to be recorded at maximum. A density determination step is carried out for determining a recording density of the contents information based on the detected actual volume and the detected nominal capacity. A recording step is carried out for recording the contents information into the optical disk at the determined recording density such that the actual volume of the contents information can fit into the nominal capacity of the optical disk.Type: ApplicationFiled: November 14, 2005Publication date: April 13, 2006Applicant: YAMAHA CORPORATIONInventors: Akira Usui, Yukihisa Nakajo
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Patent number: 7012864Abstract: An optical disk recording apparatus operates on an optical disk having circular tracks which are provisionally written with an index signal used for securing a constant linear velocity of the optical disk from an innermost circular track to an outermost circular track, and records data along the circular tracks at different linear densities on different annular zones of the optical disk. In the apparatus, a disk drive section rotates the optical disk while synchronizing the index signal successively read from the rotated optical disk with a predetermined reference clock signal to thereby maintain the constant linear velocity of the circular tracks. A clock generating section multiples or divides the reference clock signal by different rates to generate different writing clock signals in correspondence to the different annular zones of the optical disk.Type: GrantFiled: June 16, 2004Date of Patent: March 14, 2006Assignee: Yamaha CorporationInventors: Takuya Tamaru, Tatsuo Fushiki, Katsuichi Osakabe, Yusuke Konagai, Akira Usui, Kentaro Nomoto, Masaki Dojun, Kazuhiko Honda
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Publication number: 20060046325Abstract: The present invention provides a group III nitride semiconductor substrate with low defect density as well as small warp and a process for producing the same; for instance, the process according to the present invention comprises the following series of steps of: forming a metallic Ti film 63 on a sapphire substrate 61, followed by treatment of nitration to convert it into a TiN film 64 having fine pores; thereafter growing a HVPE-GaN layer 66 thereon; forming voids 65 in the HVPE-GaN layer 66 by means of effects of the metallic Ti film 63 and the TiN film 64; and peeling the sapphire substrate 61 from the region of the voids 65 to remove it therefrom.Type: ApplicationFiled: July 1, 2003Publication date: March 2, 2006Applicants: NEC Corporation, Hitachi Cable, Ltd.Inventors: Akira Usui, Masatomo Shibata, Yuichi Oshima
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Publication number: 20060046511Abstract: A structure of a substrate used for growing a crystal layer of a semiconductor, particularly a group-III nitride semiconductor and its manufacturing method. The substrate comprises two porous layers on a base. The mean opening diameter of the pores of the first porous laser, the outermost layer, is smaller than the means diameter of the pores in the second porous layer nearer to the base than the first porous layer. The first and second porous layers have volume porosities of 10 to 90%. More then 50% of the pores of the first porous layer extend from the surface of the first porous layer and reach the interface between the first and second porous layers. Even by a conventional crystal growing method, an epitaxial crystal of low defect density can be easily grown on the porous substrate.Type: ApplicationFiled: June 26, 2003Publication date: March 2, 2006Inventors: Masatomo Shibata, Yuichi Oshima, Takeshi Eri, Akira Usui, Haruo Sunagawa
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Patent number: 6980495Abstract: In an optical recording apparatus having an optical pickup, a rotating section is provided for rotating an optical disk which is formed thereon with a guide groove to define a spiral track having a plurality of rounds. The optical pickup has a light source for generating an optical beam and a diffractive grating for diffracting the optical beam to form a main beam and a pair of sub beams opposite with each other relative to the main beam. The optical pickup is operable for irradiating the main beam to the spiral track with accompanying the pair of the sub beams along apposite sides of the spiral track. A servo section operates the optical pickup to enable the main beam to trace the spiral track based on a tracking error signal derived from return lights of the sub beams reflected back from the optical disk. A recording section modulates the main beam for recording of information onto the spiral track while the optical dick is rotated.Type: GrantFiled: June 20, 2003Date of Patent: December 27, 2005Assignee: Yamaha CorporationInventors: Katsuichi Osakabe, Akira Usui, Shinji Aoshima, Hiromitsu Shibata, Masaki Dojun
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Publication number: 20050232105Abstract: An optical disk recording apparatus operates on an optical disk having circular tracks which are provisionally written with an index signal used for securing a constant linear velocity of the optical disk from an innermost circular track to an outermost circular track, and records data along the circular tracks at different linear densities on different annular zones of the optical disk. In the apparatus, a disk drive section rotates the optical disk while synchronizing the index signal successively read from the rotated optical disk with a predetermined reference clock signal to thereby maintain the constant linear velocity of the circular tracks. A clock generating section multiples or divides the reference clock signal by different rates to generate different writing clock signals in correspondence to the different annular zones of the optical disk.Type: ApplicationFiled: June 16, 2004Publication date: October 20, 2005Inventors: Yusuke Konagai, Akira Usui, Kentaro Nomoto
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Patent number: 6924159Abstract: To provide a semiconductor substrate of a group III nitride with low defect density and little warp, this invention provides a process comprising such steps of: forming a GaN layer 2 on a sapphire substrate 1 of the C face ((0001) face); forming a titanium film 3 thereon; heat-treating the substrate in an atmosphere containing hydrogen gas or a gas of a compound containing hydrogen to form voids in the GaN layer 2; and thereafter forming a GaN layer 4 on the GaN layer 2?.Type: GrantFiled: March 26, 2002Date of Patent: August 2, 2005Assignees: NEC Corporation, Hitachi Cable, Ltd.Inventors: Akira Usui, Masatomo Shibata, Yuichi Oshima
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Publication number: 20050121416Abstract: A visible image is formed on an optical disk by using an optical disk recording apparatus that forms a pit with a length defined by recording data (EFM-modulated data) by applying a laser beam onto the optical disk. At least a part of the recording data are replaced with the visible image forming data to generate the recording data containing visible image forming data. When the recording data containing the visible image forming data are recorded on the optical disk, the visible image forming data are extracted from the recording data to act as a gate signal. The visible image is formed by forming a pit defined by the recording data in an area of the gate signal.Type: ApplicationFiled: September 30, 2004Publication date: June 9, 2005Applicant: YAMAHA CORPORATIONInventors: Morito Morishima, Akira Usui, Yusuke Konagai
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Publication number: 20050104987Abstract: The present invention includes a film or video image pickup signal recording/reproduction system having an image pickup apparatus outputting an image pickup signal, a recording apparatus recording the image pickup signal, a reproduction apparatus reproducing the recorded signal, a characteristic conversion apparatus switching the characteristic of the reproduced signal, and a display apparatus displaying the signal output from the characteristic conversion apparatus. The image pickup apparatus has two kinds of gamma curve characteristics. The gamma curve characteristic data is recorded by the recording apparatus and extracted by the reproduction apparatus. The gamma curve characteristic of a reproduction image is switched by the characteristic conversion apparatus depending on the data. The image is output on a display apparatus.Type: ApplicationFiled: June 24, 2003Publication date: May 19, 2005Inventors: Ryoji Asada, Akihiro Takeuchi, Akira Usui, Yoshitaka Sakamoto, Takayuki Kimoto, Tamotsu Akeyama
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Publication number: 20050029507Abstract: A metal layer is formed directly on a nitride-based compound semiconductor base layer over a substrate body. The metal layer includes at least one metal exhibiting an atomic interaction, with assistance of a heat treatment, to atoms constituting the base layer to promote removal of constitutional atoms from the base layer, whereby pores penetrating the metal layer are formed, while many voids are formed in the nitride-based compound semiconductor base layer. An epitaxial growth of a nitride-based compound semiconductor crystal is made with an initial transient epitaxial growth, which fills the voids, and a subsequent main epitaxial growth over the porous metal layer.Type: ApplicationFiled: September 14, 2004Publication date: February 10, 2005Applicants: NEC CORPORATION, HITACHI CABLE, LTD.Inventors: Akira Usui, Masatomo Shibata, Yuichi Oshima
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Publication number: 20040228242Abstract: An optical disk recording apparatus operates on an optical disk having circular tracks which are provisionally written with an index signal used for securing a constant linear velocity of the optical disk from an innermost circular track to an outermost circular track, and records data along the circular tracks at different linear densities on different annular zones of the optical disk. In the apparatus, a disk drive section rotates the optical disk while synchronizing the index signal successively read from the rotated optical disk with a predetermined reference clock signal to thereby maintain the constant linear velocity of the circular tracks. A clock generating section multiples or divides the reference clock signal by different rates to generate different writing clock signals in correspondence to the different annular zones of the optical disk.Type: ApplicationFiled: June 16, 2004Publication date: November 18, 2004Applicant: Yamaha CorporationInventors: Takuya Tamaru, Tatsuo Fushiki, Katsuichi Osakabe, Yusuke Konagai, Akira Usui, Kentaro Nomoto, Masaki Dojun, Kazuhiko Honda
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Patent number: 6812051Abstract: A metal layer is formed directly on a nitride-based compound semiconductor base layer over a substrate body. The metal layer includes at least one metal exhibiting an atomic interaction, with assistance of a heat treatment, to atoms constituting the base layer to promote removal of constitutional atoms from the base layer, whereby pores penetrating the metal layer are formed, while many voids are formed in the nitride-based compound semiconductor base layer. An epitaxial growth of a nitride-based compound semiconductor crystal is made with an initial transient epitaxial growth, which fills the voids, and a subsequent main epitaxial growth over the porous metal layer.Type: GrantFiled: May 21, 2002Date of Patent: November 2, 2004Assignees: NEC Corporation, Hitachi Cable, Ltd.Inventors: Akira Usui, Masatomo Shibata, Yuichi Oshima