Patents by Inventor Takakazu Imai
Takakazu Imai 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: 10627261Abstract: A movement detection unit includes a movable body, a first sensor, a second sensor, and a signal processor. The movable body performs a movement in a first direction. The first sensor detects a first magnetic field change which is caused by the movement of the movable body and outputs a first signal. The second sensor is provided in the first direction at a location different from a location of the first sensor. The second sensor detects a second magnetic field change which is caused by the movement of the movable body and outputting a second signal. The signal processor includes a signal generating circuit that generates a third signal and a fourth signal on a basis of the first signal. The third signal and the fourth signal have waveforms different from each other.Type: GrantFiled: July 12, 2019Date of Patent: April 21, 2020Assignee: TDK CORPORATIONInventor: Takakazu Imai
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Patent number: 10498198Abstract: A magnetic sensor includes a magnetic detection element circuit that includes first and second magnetic detection elements, which are connected in series, and an output terminal, which is positioned between the first and second magnetic detection elements; an impedance matching device, which has a prescribed input voltage range and is connected to an output terminal of the magnetic detection element circuit; a first current supply source, which supplies an electric current to the magnetic detection element circuit; and a second current supply source, which supplies an electric current to the impedance matching device. A resistor is provided between the output terminal of the magnetic detection element circuit and the first current supply source and/or a reference electric potential point.Type: GrantFiled: December 5, 2017Date of Patent: December 3, 2019Assignee: TDK CorporationInventors: Yosuke Komasaki, Naoki Ohta, Hayato Miyashita, Takakazu Imai, Hiraku Hirabayashi, Masanori Sakai, Satoshi Abe, Tsuyoshi Umehara
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Publication number: 20190360842Abstract: A movement detection unit includes a movable body, a first sensor, a second sensor, and a signal processor. The movable body performs a movement in a first direction. The first sensor detects a first magnetic field change which is caused by the movement of the movable body and outputs a first signal. The second sensor is provided in the first direction at a location different from a location of the first sensor. The second sensor detects a second magnetic field change which is caused by the movement of the movable body and outputting a second signal. The signal processor includes a signal generating circuit that generates a third signal and a fourth signal on a basis of the first signal. The third signal and the fourth signal have waveforms different from each other.Type: ApplicationFiled: July 12, 2019Publication date: November 28, 2019Applicant: TDK CORPORATIONInventor: Takakazu IMAI
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Patent number: 10378929Abstract: A movement detection unit includes a movable body, a first sensor, a second sensor, and a signal processor. The movable body performs a movement in a first direction. The first sensor detects a first magnetic field change which is caused by the movement of the movable body and outputs a first signal. The second sensor is provided in the first direction at a location different from a location of the first sensor. The second sensor detects a second magnetic fled change which is caused by the movement of the movable body and outputting a second signal. The signal processor includes a signal generating circuit that generates a third signal and a fourth signal on a basis of the first signal. The third signal and the fourth signal have waveforms different from each other.Type: GrantFiled: December 21, 2016Date of Patent: August 13, 2019Assignee: TDK CORPORATIONInventor: Takakazu Imai
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Publication number: 20180254686Abstract: A magnetic sensor includes a magnetic detection element circuit that includes first and second magnetic detection elements, which are connected in series, and an output terminal, which is positioned between the first and second magnetic detection elements; an impedance matching device, which has a prescribed input voltage range and is connected to an output terminal of the magnetic detection element circuit; a first current supply source, which supplies an electric current to the magnetic detection element circuit; and a second current supply source, which supplies an electric current to the impedance matching device. A resistor is provided between the output terminal of the magnetic detection element circuit and the first current supply source and/or a reference electric potential point.Type: ApplicationFiled: December 5, 2017Publication date: September 6, 2018Inventors: Yosuke Komasaki, Naoki Ohta, Hayato Miyashita, Takakazu Imai, Hiraku Hirabayashi, Masanori Sakai, Satoshi Abe, Tsuyoshi Umehara
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Publication number: 20170184422Abstract: A movement detection unit includes a movable body, a first sensor, a second sensor, and a signal processor. The movable body performs a movement in a first direction. The first sensor detects a first magnetic field change which is caused by the movement of the movable body and outputs a first signal. The second sensor is provided in the first direction at a location different from a location of the first sensor. The second sensor detects a second magnetic fled change which is caused by the movement of the movable body and outputting a second signal. The signal processor includes a signal generating circuit that generates a third signal and a fourth signal on a basis of the first signal. The third signal and the fourth signal have waveforms different from each other.Type: ApplicationFiled: December 21, 2016Publication date: June 29, 2017Applicant: TDK CORPORATIONInventor: Takakazu IMAI
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Patent number: 9086444Abstract: Provided is a magnetic field detection device and a current sensor capable of increasing the degree of freedom in selecting the type of the magnetic field detection element. A magnetic field detection device 1 includes a conductor 3 that generates a magnetic field; a C core 2 provided so as to surround the conductor 3; and a magnetic field detection element 4 that detects a magnetic field. The C core 2 has a gap G1, and the magnetic field detection element 4 is disposed at a position where the magnetic field generated from the conductor 3 can be detected, the position being outside the gap G1. Since the direction of the magnetic flux varies outside of the gap G1 from place to place, the direction of the magnetic flux that passes through the magnetic field detection element 4 can be arbitrarily selected by arbitrarily selecting the installation location of the magnetic field detection element 4. Therefore, the degree of freedom in selecting the type of the magnetic field detection element 4 is increased.Type: GrantFiled: December 28, 2010Date of Patent: July 21, 2015Assignee: TDK CORPORATIONInventors: Hiroyoshi Nakajima, Takakazu Imai, Takuya Daigo, Reiji Okuno, Junya Fukuda
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Patent number: 8358129Abstract: A magnetic coupling-type isolator includes a primary coil configured to generate a first magnetic field in accordance with an input signal, a bias coil configured to generate a second magnetic field in accordance with a bias signal, a first magneto-resistive element having a magnetic resistance increased by the first magnetic field and decreased by the second magnetic field, a second magneto-resistive element having a magnetic resistance decreased by the first magnetic field and increased by the second magnetic field, and a comparator configured to output an output signal in accordance with a difference between the magnetic resistance of the first magneto-resistive element and the magnetic resistance of the second magneto-resistive element.Type: GrantFiled: November 25, 2009Date of Patent: January 22, 2013Assignee: TDK CorporationInventors: Takakazu Imai, Reiji Okuno
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Publication number: 20120293170Abstract: Provided is a magnetic field detection device and a current sensor capable of increasing the degree of freedom in selecting the type of the magnetic field detection element. A magnetic field detection device 1 includes a conductor 3 that generates a magnetic field; a C core 2 provided so as to surround the conductor 3; and a magnetic field detection element 4 that detects a magnetic field. The C core 2 has a gap G1, and the magnetic field detection element 4 is disposed at a position where the magnetic field generated from the conductor 3 can be detected, the position being outside the gap G1. Since the direction of the magnetic flux varies outside of the gap G1 from place to place, the direction of the magnetic flux that passes through the magnetic field detection element 4 can be arbitrarily selected by arbitrarily selecting the installation location of the magnetic field detection element 4. Therefore, the degree of freedom in selecting the type of the magnetic field detection element 4 is increased.Type: ApplicationFiled: December 28, 2010Publication date: November 22, 2012Inventors: Hiroyoshi Nakajima, Takakazu Imai, Takuya Daigo, Reiji Okuno, Junya Fukuda
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Patent number: 8164331Abstract: The magnetic field measurement method has: a step of preparing a magnetic sensor which includes: a magneto-resistive effect element having a magnetization-free layer and a magnetization fixed layer, and having a longitudinal direction; and magnetic field application means, wherein the magnetization direction of the magnetization fixed layer is fixed in a direction which forms an angle equal to or less than 45 degrees to the longitudinal direction, and a magnetic field generated by the magnetic field application means forms an angle equal to or less than 45 degrees to the longitudinal direction; a step of saturating the magnetization of the magnetization-free layer by the magnetic field application means and magnetizing the magnetization-free layer in one direction in the longitudinal direction; and a step of measuring the strength of an external magnetic field by applying the external magnetic field to the magnetization-free layer in the other direction in the longitudinal direction.Type: GrantFiled: March 26, 2009Date of Patent: April 24, 2012Assignee: TDK CorporationInventors: Takakazu Imai, Junya Fukuda, Kei Tanabe
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Patent number: 8164330Abstract: The magnetic sensor according to the present invention includes: a magneto-resistive effect element which has a stacked body in which a magnetization-free layer, a nonmagnetic layer, and a magnetization fixed layer are stacked in this order, and the longitudinal direction of which is a direction perpendicular to the stacking direction; and a current path layer which is provided on the magneto-resistive effect element via an insulation layer so as to be spaced apart from the magneto-resistive effect element in the stacking direction, and which generates a magnetic field by being supplied with a current. The current path layer extends in a direction which forms an angle between 0 and 45 degrees to the longitudinal direction of the magneto-resistive effect element when viewed from the stacking direction.Type: GrantFiled: February 12, 2009Date of Patent: April 24, 2012Assignee: TDK CorporationInventors: Takakazu Imai, Kei Tanabe
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Patent number: 7982640Abstract: A digital signal transmitting apparatus includes an encoder which converts parallel input signals of multiple channels into serial data in a manner synchronized with a first clock signal, and a decoder which converts the serial data into parallel output signals of the multiple channels in a manner synchronized with a second clock signal operating in a manner asynchronous with the first clock signal. The serial data has a different period and a different duty factor corresponding to each combination of the logical values of the parallel input signals of the multiple channels.Type: GrantFiled: September 30, 2009Date of Patent: July 19, 2011Assignee: TDK CorporationInventors: Reiji Okuno, Takakazu Imai, Takeo Gokita
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Publication number: 20100127803Abstract: A magnetic coupling-type isolator includes a primary coil configured to generate a first magnetic field in accordance with an input signal, a bias coil configured to generate a second magnetic field in accordance with a bias signal, a first magneto-resistive element having a magnetic resistance increased by the first magnetic field and decreased by the second magnetic field, a second magneto-resistive element having a magnetic resistance decreased by the first magnetic field and increased by the second magnetic field, and a comparator configured to output an output signal in accordance with a difference between the magnetic resistance of the first magneto-resistive element and the magnetic resistance of the second magneto-resistive element.Type: ApplicationFiled: November 25, 2009Publication date: May 27, 2010Applicant: TDK CORPORATIONInventors: Takakazu Imai, Reiji Okuno
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Publication number: 20100079316Abstract: A digital signal transmitting apparatus includes an encoder which converts parallel input signals of multiple channels into serial data in a manner synchronized with a first clock signal, and a decoder which converts the serial data into parallel output signals of the multiple channels in a manner synchronized with a second clock signal operating in a manner asynchronous with the first clock signal. The serial data has a different period and a different duty factor corresponding to each combination of the logical values of the parallel input signals of the multiple channels.Type: ApplicationFiled: September 30, 2009Publication date: April 1, 2010Applicant: TDK CORPORATIONInventors: Reiji Okuno, Takakazu Imai, Takeo Gokita
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Patent number: 7660134Abstract: A DC-DC converter has a switching circuit including switching elements at the high-side and at the low-side, an inductor connected to the output end of the switching circuit, a smoothing capacitor connected to the inductor, a switching control circuit for supplying a switching pulse to the switching elements, and a circuit. The circuit detects that a state that the switching element at the high side is switched off and the switching element at the low side is switched on is maintained for a predetermined period or longer. In this case, the circuit forcibly switches off the switching element at the low side.Type: GrantFiled: October 26, 2006Date of Patent: February 9, 2010Assignee: TDK CorporationInventors: Takakazu Imai, Takeo Gokita
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Publication number: 20090243608Abstract: The magnetic field measurement method has: a step of preparing a magnetic sensor which includes: a magneto-resistive effect element having a magnetization-free layer and a magnetization fixed layer, and having a longitudinal direction; and magnetic field application means, wherein the magnetization direction of the magnetization fixed layer is fixed in a direction which forms an angle equal to or less than 45 degrees to the longitudinal direction, and a magnetic field generated by the magnetic field application means forms an angle equal to or less than 45 degrees to the longitudinal direction; a step of saturating the magnetization of the magnetization-free layer by the magnetic field application means and magnetizing the magnetization-free layer in one direction in the longitudinal direction; and a step of measuring the strength of an external magnetic field by applying the external magnetic field to the magnetization-free layer in the other direction in the longitudinal direction.Type: ApplicationFiled: March 26, 2009Publication date: October 1, 2009Applicant: TDK CORPORATIONInventors: Takakazu IMAI, Junya FUKUDA, Kei TANABE
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Publication number: 20090206833Abstract: The magnetic sensor according to the present invention includes: a magneto-resistive effect element which has a stacked body in which a magnetization-free layer, a nonmagnetic layer, and a magnetization fixed layer are stacked in this order, and the longitudinal direction of which is a direction perpendicular to the stacking direction; and a current path layer which is provided on the magneto-resistive effect element via an insulation layer so as to be spaced apart from the magneto-resistive effect element in the stacking direction, and which generates a magnetic field by being supplied with a current. The current path layer extends in a direction which forms an angle between 0 and 45 degrees to the longitudinal direction of the magneto-resistive effect element when viewed from the stacking direction.Type: ApplicationFiled: February 12, 2009Publication date: August 20, 2009Applicant: TDK CORPORATIONInventors: Takakazu IMAI, Kei TANABE
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Patent number: 7498784Abstract: A current flowing through a measuring target coil increases when a pulse signal is high. A voltage corresponding to instantaneous value of the current through the coil is input to input terminal. A blanking signal generator circuit generates signal which has predetermined pulse width and rises in synchronization with rise of the pulse signal. During period in which this signal is high, first switch becomes ON and first capacitor holds the voltage at the input terminal. A second switch becomes ON when first switch becomes OFF to connect second capacitor to connection node between resistors, and disconnects second capacitor from connection node when the pulse signal becomes low. Second capacitor is charged with voltage corresponding to average value of an amount of increase in the current through the coil. A voltage obtained by adding the voltage charged in first capacitor to this charged voltage is supplied to third capacitor.Type: GrantFiled: July 26, 2006Date of Patent: March 3, 2009Assignee: TDK CorporationInventors: Takeo Gokita, Takakazu Imai
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Publication number: 20070090821Abstract: A DC-DC converter has a switching circuit including switching elements at the high-side and at the low-side, an inductor connected to the output end of the switching circuit, a smoothing capacitor connected to the inductor, a switching control circuit for supplying a switching pulse to the switching elements, and a circuit. The circuit detects that a state that the switching element at the high side is switched off and the switching element at the low side is switched on is maintained for a predetermined period or longer. In this case, the circuit forcibly switches off the switching element at the low side.Type: ApplicationFiled: October 26, 2006Publication date: April 26, 2007Inventors: Takakazu Imai, Takeo Gokita
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Publication number: 20070025048Abstract: A current flowing through a measuring target coil increases when a pulse signal is high. A voltage corresponding to instantaneous value of the current through the coil is input to input terminal. A blanking signal generator circuit generates signal which has predetermined pulse width and rises in synchronization with rise of the pulse signal. During period in which this signal is high, first switch becomes ON and first capacitor holds the voltage at the input terminal. A second switch becomes ON when first switch becomes OFF to connect second capacitor to connection node between resistors, and disconnects second capacitor from connection node when the pulse signal becomes low. Second capacitor is charged with voltage corresponding to average value of an amount of increase in the current through the coil. A voltage obtained by adding the voltage charged in first capacitor to this charged voltage is supplied to third capacitor.Type: ApplicationFiled: July 26, 2006Publication date: February 1, 2007Applicant: TDK CORPORATIONInventors: Takeo Gokita, Takakazu Imai