Tdk Corporation

Tetsuya Nishiyama

Noritaka Chiyo

Mitsunari Suzuki

Yasuhiro Terasaki

Takashi Kikukawa

Koji Mishima

Tsunehiro Saen

Hiroyasu Inoue

Yoshinori Sato

Hajime Utsunomiya

Narutoshi Fukuzawa

Noriyuki Kawano

Toshinori Matsuura

Yoshihiro Saitoh

Takeshi Kamono

A coil unit includes a non-magnetic conductive plate which is disposed along an axis of a coil, and a magnetic body. The magnetic body includes a first portion which is positioned in an outer side than an outline of one side of the conductive plate in the axis direction of the coil, and a second portion which is positioned in an outer side than an outline of the other side of the conductive plate in the axis direction of the coil. When viewing from the axis direction of the coil, the first and second portions are positioned on a side of the conductive plate where is opposite to a side which faces the coil.

Coil unit and wireless power transmission device

A coil unit includes a non-magnetic conductive plate which is disposed in an arrangement direction of first and second coils have reverse winding direction to each other, and a magnetic body. The magnetic body includes a first portion which is positioned in an outer side than an outline of one side of the conductive plate in the arrangement direction of the first and second coils, and a second portion which is positioned in an outer side than an outline of the other side of the conductive plate in the arrangement direction of the first and second coils. When viewing from the arrangement direction of the first and second coils, the first and second portions are positioned on a side of the conductive plate where is opposite to a side which faces the first and second coils.

A coil unit, a wireless power feeding device, a wireless power receiving device, and a wireless power transmission device are provided that are capable of reducing high voltage induced on the metal part. A coil unit Luincludes a power transmission coil L, a first reactance circuit Xthat is connected to one end portion of the winding of the power transmission coil Land forms a resonant circuit together with the power transmission coil L, a metal part SD disposed on the same side as the back side of the power transmission coil L, and a first adjustment capacitor Cconnected between the other end portion of the winding of the power transmission coil Land the metal part SD.

Coil unit, wireless power feeding device, wireless power receiving device, and wireless power transmission device

A coil unit, a wireless power feeding device, a wireless power receiving device, and a wireless power transmission device are provided that can reduce high induced voltage on the metal part. A coil unit includes a power transmission coil, reactance circuits and that each form a resonant circuit together with the power transmission coil, and a metal part disposed on the same side as the back side of the power transmission coil. A ratio between a first reactance value of the first reactance circuit and a second reactance value of the second reactance circuit is set based on the ratio of the mean distance between the winding and the metal part in a part of the winding from the other end to the central portion to the mean distance between the winding and the metal part in a part of the winding from one end to the central portion.

A power feeding coil unit includes a power feeding coil, and first and second auxiliary coils located outside of the region defined by a wire of the power feeding coil. The axis of the first auxiliary coil and the axis of the second auxiliary coil are substantially perpendicular to the axis of the power feeding coil. The power feeding coil and the first and second auxiliary coils simultaneously generate respective magnetic fluxes, each of which interlinks the corresponding one of the power feeding coil and the first and second auxiliary coils in a direction from the center to the outside of the power feeding coil unit.

Power feeding coil unit and wireless power transmission device

A power feeding coil unit includes a power feeding coil, and first and second auxiliary coils arranged so that a wire of the first auxiliary coil and a wire of the second auxiliary coil do not overlap a wire of the a power feeding coil when viewed from a direction perpendicular to an axial direction of the power feeding coil. A direction of circulation of a magnetic flux generated by the first auxiliary coil and a magnetic flux generated by the second auxiliary coil are opposite to a direction of circulation of a magnetic flux generated by the power feeding coil. An axes of the first and second auxiliary coils are substantially perpendicular to a power feeding direction of the power feeding coil, and are not aligned with the axis of the power feeding coil.

A power feeding coil unit includes a power feeding coil, and an auxiliary coil. The auxiliary coil is arranged not to interlink with a magnetic flux that interlinks with a power receiving coil that is arranged to face the power feeding coil during power feeding. An axial direction of the auxiliary coil is nonparallel to an opposing direction of the power feeding coil and the power receiving coil. A direction of circulation of a magnetic flux generated by the auxiliary coil is opposite to a direction of circulation of a magnetic flux generated by the power feeding coil.

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.

Wireless power receiver, wireless power transmission system, and power controller

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.

Optical drive device

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.

Optical drive apparatus

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.

Optical drive device and amplification rate determining method

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.

Optical head device and optical recording and reading system

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.

Growing community of inventors

Tokyo, Japan

Tetsuya Nishiyama