Patents by Inventor Tetsuya Nishiyama
Tetsuya Nishiyama 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: 8830803Abstract: An optical drive apparatus that reproduces an optical disk having a land and a groove, the optical drive apparatus including a first tracking-error-signal generating unit that generates a first tracking error signal by using a DPD method, a second tracking-error-signal generating unit that generates a second tracking error signal by using a DPP method, a tracking servo unit that controls the optical system, and a determining unit that determines that an irradiation point of an optical beam is in a non-recorded area. The tracking servo unit switches over to a control based on the second tracking error signal in response to a result of determination by the determining unit during performing a control based on the first tracking error signal.Type: GrantFiled: August 10, 2010Date of Patent: September 9, 2014Assignee: TDK CorporationInventors: Tetsuya Nishiyama, Takashi Kikukawa
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Patent number: 8542565Abstract: An optical drive apparatus includes: a phase-difference detection-signal generating unit that generates PEDr based on PEROd and PEFOd obtained by delaying a phase-lead output signal indicating a phase lead amount of DA with respect to DB and X that is changed to high at a timing at which NAND of the DA and the DB is changed from high to low and changed to low at a timing at which OR of the DA and the DB is changed from high to low, and generates PADr based on PAROd and PAFOd obtained by delaying a phase-lag output signal indicating a phase lag amount of the DA with respect to the DB by a predetermined time and the X; and a DPD signal generating unit that generates a phase difference signal indicating a phase difference between the DA and the DB based on the PEDr and the PADr, and generates a DPD signal based on the phase difference signal.Type: GrantFiled: October 13, 2010Date of Patent: September 24, 2013Assignee: TDK CorporationInventor: Tetsuya Nishiyama
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Publication number: 20120223587Abstract: A wireless power receiver receives, at a receiving coil, AC power fed from a feeding coil by wireless using a magnetic field resonance phenomenon between the feeding coil and receiving coil. The wireless power receiver includes a loading circuit and a power controller. The loading circuit includes a loading coil that is magnetically coupled to the receiving coil to receive the AC power from the receiving coil and a load that receives the AC power supplied from the loading coil. The power controller includes a measurement unit and an adjustment unit. The measurement unit measures the receiving power of the load. The adjustment unit brings the receiving power close to its maximum value by changing the impedance of the loading circuit.Type: ApplicationFiled: October 10, 2011Publication date: September 6, 2012Inventors: Tetsuya NISHIYAMA, Yoshihiro Saitoh
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Patent number: 8193958Abstract: Pulses that are generated from multiple analog input signals are sampled, and signal elements contained in the analog signals are extracted accurately using the said sampling pulses. Binarization circuits where analog input signals A, B, C, and D are converted into pulse signals; a logic operation circuit that generates a sampling pulse upon receiving the input of the 4 pulse signals; and a sample-and-hold circuit samples and holds an input RF signal based on the sampling pulse in order to extract accurately signal elements contained in said RF signal by means of sampling of the RF signal.Type: GrantFiled: May 8, 2008Date of Patent: June 5, 2012Assignee: Texas Instruments IncorporatedInventors: Masayuki Tahara, Kenji Namba, Tetsuya Nishiyama
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Patent number: 8189436Abstract: An optical drive device generates a first push-pull signal and a first sum signal based on a light receiving amount in two light receiving areas of which each width in a signal light tangent direction is smaller than a diameter of a spot of signal light, generates a first normalized push-pull signal by normalizing the first push-pull signal by using the first sum signal, and generates a tracking error signal based on the first normalized push-pull signal.Type: GrantFiled: August 24, 2009Date of Patent: May 29, 2012Assignee: TDKInventor: Tetsuya Nishiyama
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Patent number: 8107349Abstract: An optical head device (optical head) for a multi-layered optical recording medium has a focus control mechanism that makes use of astigmatism. The focus control mechanism has a sensor lens that includes a cylindrical lens. The focus control mechanism causes a light beam having passed through the sensor lens to have astigmatism, thereby being focused linearly in the Y direction on a front focal line located closer to the sensor lens and focused linearly in the X direction at a rear focal line located farther therefrom. The optical head also includes a photodetector which is disposed between the front focal line and the rear focal line to detect a focal position from the shape of a light beam. At the position of the front focal line, a shield plate with a window portion is disposed. The window portion has a size so as to allow the focal line to pass therethrough and shield stray light reflected from an unfocused recording layer.Type: GrantFiled: September 14, 2009Date of Patent: January 31, 2012Assignee: TDK CorporationInventors: Noriyuki Kawano, Tetsuya Nishiyama, Yoshinori Sato, Koji Mishima, Hajime Utsunomiya
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Patent number: 8081548Abstract: A multilayer optical recording medium having three or more information recording layers is irradiated with a laser beam, and a first signal obtained from the reflected laser beam is subjected to a frequency filter. A second signal obtained by filtration through a high-pass filter is used to evaluate the characteristics of the multilayer optical recording medium. In this manner, even in a multilayer optical recording medium having three or more information recording layers, the influence of the variation of the thickness and material of the information recording layers and the influence of the variation of the thickness of a spacer layer can be clearly determined and evaluated.Type: GrantFiled: January 27, 2009Date of Patent: December 20, 2011Assignee: TDK CorporationInventors: Koji Mishima, Hiroyasu Inoue, Takashi Kikukawa, Tetsuya Nishiyama
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Publication number: 20110128833Abstract: An optical drive apparatus that reproduces an optical disk having a land and a groove, the optical drive apparatus including a first tracking-error-signal generating unit that generates a first tracking error signal by using a DPD method, a second tracking-error-signal generating unit that generates a second tracking error signal by using a DPP method, a tracking servo unit that controls the optical system, and a determining unit that determines that an irradiation point of an optical beam is in a non-recorded area. The tracking servo unit switches over to a control based on the second tracking error signal in response to a result of determination by the determining unit during performing a control based on the first tracking error signal.Type: ApplicationFiled: August 10, 2010Publication date: June 2, 2011Inventors: Tetsuya NISHIYAMA, Takashi KIKUKAWA
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Publication number: 20110085431Abstract: An optical drive apparatus includes: a phase-difference detection-signal generating unit that generates PEDr based on PEROd and PEFOd obtained by delaying a phase-lead output signal indicating a phase lead amount of DA with respect to DB and X that is changed to high at a timing at which NAND of the DA and the DB is changed from high to low and changed to low at a timing at which OR of the DA and the DB is changed from high to low, and generates PADr based on PAROd and PAFOd obtained by delaying a phase-lag output signal indicating a phase lag amount of the DA with respect to the DB by a predetermined time and the X; and a DPD signal generating unit that generates a phase difference signal indicating a phase difference between the DA and the DB based on the PEDr and the PADr, and generates a DPD signal based on the phase difference signal.Type: ApplicationFiled: October 13, 2010Publication date: April 14, 2011Inventor: Tetsuya NISHIYAMA
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Publication number: 20100296377Abstract: A multilayer optical recording medium having three or more information recording layers is irradiated with a laser beam, and a first signal obtained from the reflected laser beam is subjected to a frequency filter. A second signal obtained by filtration through a high-pass filter is used to evaluate the characteristics of the multilayer optical recording medium. In this manner, even in a multilayer optical recording medium having three or more information recording layers, the influence of the variation of the thickness and material of the information recording layers and the influence of the variation of the thickness of a spacer layer can be clearly determined and evaluated.Type: ApplicationFiled: January 27, 2009Publication date: November 25, 2010Inventors: Koji Mishima, Hiroyasu Inoue, Takashi Kikukawa, Tetsuya Nishiyama
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Publication number: 20100224767Abstract: A photodetector used in, for example, an optical pickup device includes: a photodetection unit including a plurality of photodetection elements and provided on a semiconductor chip; a light transmitting unit formed on the upper surface of the photodetection unit; and a light shielding layer having an optical aperture and disposed on the upper surface of the light transmitting unit, with these components being formed integrally. The light transmitting unit is configured such that the distance between the optical aperture and the photodetection unit is maintained constant, and the optical aperture is formed such that the inner portion of an incident light beam passes therethrough. The positioning of the photodetector and the positioning of the optical aperture such as a pinhole or a slit for adjusting the light beam entering the photodetection elements of the photodetector can be made at the same time.Type: ApplicationFiled: March 1, 2010Publication date: September 9, 2010Applicant: TDK CORPORATIONInventors: Noriyuki KAWANO, Tetsuya NISHIYAMA, Hironobu NISHIMURA, Tomohiko ISHIDA
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Publication number: 20100103799Abstract: An optical head device (optical head) for a multi-layered optical recording medium has a focus control mechanism that makes use of astigmatism. The focus control mechanism has a sensor lens that includes a cylindrical lens. The focus control mechanism causes a light beam having passed through the sensor lens to have astigmatism, thereby being focused linearly in the Y direction on a front focal line located closer to the sensor lens and focused linearly in the X direction at a rear focal line located farther therefrom. The optical head also includes a photodetector which is disposed between the front focal line and the rear focal line to detect a focal position from the shape of a light beam. At the position of the front focal line, a shield plate with a window portion is disposed. The window portion has a size so as to allow the focal line to pass therethrough and shield stray light reflected from an unfocused recording layer.Type: ApplicationFiled: September 14, 2009Publication date: April 29, 2010Applicant: TDK CORPORATIONInventors: Noriyuki Kawano, Tetsuya Nishiyama, Yoshinori Sato, Koji Mishima, Hajime Utsunomiya
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Publication number: 20100046340Abstract: An optical drive device generates a fist push-pull signal and a first sum signal based on a light receiving amount in two light receiving areas of which each width in a signal light tangent direction is smaller than a diameter of a spot of signal light, generates a first normalized push-pull signal by normalizing the first push-pull signal by using the first suits signal, and generates a tracking error signal based on the first normalized push-pull signal.Type: ApplicationFiled: August 24, 2009Publication date: February 25, 2010Applicant: TDK CorporationInventor: Tetsuya NISHIYAMA
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Publication number: 20090219797Abstract: Pulses that are generated from multiple analog input signals are sampled, and signal elements contained in the analog signals are extracted accurately using the said sampling pulses. Binarization circuits where analog input signals A, B, C, and D are converted into pulse signals; a logic operation circuit that generates a sampling pulse upon receiving the input of the 4 pulse signals; and a sample-and-hold circuit samples and holds an input RF signal based on the sampling pulse in order to extract accurately signal elements contained in said RF signal by means of sampling of the RF signal.Type: ApplicationFiled: May 8, 2008Publication date: September 3, 2009Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Masayuki Tahara, Kenji Nanba, Tetsuya Nishiyama
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Publication number: 20020093385Abstract: An oscillation circuit including first and second voltage-controlled oscillator each having a resonance circuit including a pair of varactor diodes, and first and second buffer amplifier for feeding-back high frequency signals generated from the first and second voltage-controlled oscillator to the second and first voltage-controlled oscillators, respectively. A control voltage is applied to the varactor diodes to generate output high frequency signals having a second frequency and a mutual phase difference of 90 degrees from the first and second voltage-controlled oscillators generate. By adjusting an amplitude of the control voltage, resonant points of the resonance circuits of the first and second voltage-controlled oscillators are changed and the frequency of the output high frequency signals is changed, while phase noise can be sufficiently suppressed over a wide frequency range and a power consumption can be lowered.Type: ApplicationFiled: December 27, 2001Publication date: July 18, 2002Applicant: TDK CORPORATIONInventors: Tetsuya Nishiyama, Hiroshi Kobayashi