Patents by Inventor Hirofumi Yoshikawa
Hirofumi Yoshikawa 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: 20230337449Abstract: A light-emitting element includes the following: a first electrode and a second electrode; and a light-emitting layer disposed between the first electrode and the second electrode. The light-emitting layer includes a plurality of quantum dots, and a mixed crystalline body-containing at least one of ZnS or ZnSe and containing Zn(OH)2.Type: ApplicationFiled: September 28, 2020Publication date: October 19, 2023Inventors: HIROFUMI YOSHIKAWA, TAKAHIRO DOE, Masaki YAMAMOTO
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Publication number: 20230276649Abstract: A light-emitting element includes: a first electrode; a second electrode disposed opposite the first electrode; a light-emitting layer disposed between the first electrode and the second electrode and containing quantum dots; and a carrier transport layer disposed between the first electrode and a surface of the light-emitting layer on a second electrode side, including a plurality of protrusions extending toward the second electrode side, and containing a carrier transport material, wherein at least parts of the plurality of protrusions of the carrier transport layer and at least parts of a plurality of gaps between the plurality of protrusions are covered by the quantum dots.Type: ApplicationFiled: July 22, 2020Publication date: August 31, 2023Inventors: HIROFUMI YOSHIKAWA, YOSHIHIRO UETA, TAKAHIRO DOE, Masaki YAMAMOTO, DAISUKE TOYOSHIMA
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Publication number: 20230136993Abstract: A light-emitting element includes a light-emitting layer, and the light-emitting layer includes a plurality of quantum dots covered by shells containing a ferritin protein.Type: ApplicationFiled: February 4, 2020Publication date: May 4, 2023Applicant: SHARP KABUSHIKI KAISHAInventors: HIROFUMI YOSHIKAWA, TATSUYA RYOHWA, Masaki YAMAMOTO, TAKAHIRO DOE
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Publication number: 20220344606Abstract: A display device includes: ferritin encaging a first quantum dot and modified with a first peptide bound to a first pixel electrode; and ferritin encaging a second quantum dot and modified with a second peptide bound to a second pixel electrode. A first metal material and a second metal material are of different types.Type: ApplicationFiled: October 2, 2019Publication date: October 27, 2022Inventors: HIROFUMI YOSHIKAWA, TATSUYA RYOHWA, Masumi KUBO, TAKAHIRO DOE, Masaki YAMAMOTO
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Publication number: 20220320191Abstract: A display device includes a plurality of pixel electrodes, a common electrode common to the plurality of pixel electrodes, and a light-emitting layer sandwiched between the plurality of pixel electrodes and the common electrode. The light-emitting layer includes quantum dots covered by ferritin. Each of the plurality of pixel electrodes and the quantum dots are bonded via a peptide modifying the ferritin.Type: ApplicationFiled: October 2, 2019Publication date: October 6, 2022Inventors: HIROFUMI YOSHIKAWA, TATSUYA RYOHWA, Masumi KUBO, TAKAHIRO DOE, Masaki YAMAMOTO
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Publication number: 20220165973Abstract: A light-emitting element includes: an anode electrode configured to supply holes; a cathode electrode configured to supply electrons; and a light-emitting layer disposed between the anode electrode and the cathode electrode. The light-emitting layer includes a plurality of quantum dot phosphors configured to emit light in conjunction with combining of holes supplied from the anode electrode and electrons supplied from the cathode electrode and a p-type dopant.Type: ApplicationFiled: March 11, 2019Publication date: May 26, 2022Inventors: HIROFUMI YOSHIKAWA, TATSUYA RYOHWA, Masaki YAMAMOTO, TAKAHIRO DOE
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Publication number: 20220158108Abstract: A light-emitting element includes: an anode; a cathode; and a light-emitting layer between the anode and the cathode, wherein the light-emitting layer contains quantum dots, and the quantum dots have a number average particle diameter greater than or equal to DLO2 and less than or equal to 100 nm, where DLO2 is a particle diameter of the quantum dots when the quantum dots exhibit an energy gap, between a ground state and a first excited state of a conduction band thereof, that is equivalent to twice an LO phonon energy of a material for the quantum dots.Type: ApplicationFiled: February 27, 2019Publication date: May 19, 2022Inventors: HIROFUMI YOSHIKAWA, TATSUYA RYOHWA, Masaki YAMAMOTO, TAKAHIRO DOE
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Publication number: 20210296517Abstract: Provided is an infrared detector capable of achieving high sensitivity with little noise. An infrared detector includes: contact layers; a photoelectric conversion layer; a barrier layer; and an insertion layer. Each of the contact layers is doped with a dopant. The photoelectric conversion layer is placed between the contact layers, and includes a quantum layer (quantum dots) and an intermediate layer. The barrier layer is placed between the photoelectric conversion layer and one of the contact layers. The insertion layer is placed between, and in contact with, the photoelectric conversion layer and the one contact layer.Type: ApplicationFiled: March 11, 2021Publication date: September 23, 2021Inventors: HIROFUMI YOSHIKAWA, YASUHIKO ARAKAWA
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Patent number: 10866143Abstract: An infrared photodetection system is provided that is capable of measuring infrared light up to high-temperature regions while improving a temperature resolution for low-temperature regions without increasing image-acquisition time even if the measuring temperature range varies. The infrared photodetection system is set up to exhibit sensitivity spectrum SSP1 for high sensitivity (for low temperature use) and sensitivity spectrum SSP2 for low sensitivity (for high temperature use) in the transmission band of the bandpass filter when different voltages are applied to a quantum-dot infrared photodetector. The infrared photodetection system then integrates temperature data for the infrared light detected using sensitivity spectrum SSP1 and temperature data for the infrared light detected using sensitivity spectrum SSP2, in order to output a temperature distribution in a measurement region.Type: GrantFiled: March 28, 2019Date of Patent: December 15, 2020Assignees: SHARP KABUSHIKI KAISHA, THE UNIVERSITY OF TOKYOInventors: Takahiro Doe, Hirofumi Yoshikawa, Tazuko Kitazawa, Yasuhiko Arakawa
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Publication number: 20200378833Abstract: Provided is an infrared detection apparatus without a bandpass filter and capable of reducing an error produced when a temperature of an object is calculated. A detection unit has a quantum-dot stacked structure. A first voltage and a second voltage are respectively provided for setting a first responsivity peak wavelength and a second responsivity peak wavelength to be used for detecting an infrared ray in the detection unit. The second responsivity peak wavelength is different from the first responsivity peak wavelength. A detector detects (i) a first photocurrent to be output from the detection unit when the first voltage is applied to the photoelectric conversion layer, and (ii) a second photocurrent to be output from the detection unit when the second voltage is applied to the photoelectric conversion layer. A calculator calculates a temperature of an object based on the first photocurrent and the second photocurrent detected by the detector.Type: ApplicationFiled: June 1, 2020Publication date: December 3, 2020Inventors: HIROFUMI YOSHIKAWA, TAKAHIRO DOE, YASUHIKO ARAKAWA
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Patent number: 10811554Abstract: A high detectivity infrared photodetector is provided. An infrared photodetector 10 includes n-type semiconductor layers 3 and 5 and a photoelectric conversion layer 4. The photoelectric conversion layer 4 includes quantum dots 411, a barrier layer 42, and a single-sided barrier layer 43. The single-sided barrier layer 43 is inserted between the barrier layer 42 and the n-type semiconductor layer 5 and has a wider band gap than does the barrier layer 42. Letting y be an energy level difference between the bottom of the conduction band of the single-sided barrier layer 43 and the bottom of the conduction band of the n-type semiconductor layer 5, z be a voltage in volts applied to the photoelectric conversion layer 4, and d be a thickness in nanometers of the photoelectric conversion layer 4, the infrared photodetector 10 satisfies y?27×exp(0.64×z/(d×10000)).Type: GrantFiled: June 14, 2019Date of Patent: October 20, 2020Assignees: SHARP KABUSHIKI KAISHA, THE UNIVERSITY OF TOKYOInventors: Hirofumi Yoshikawa, Takahiro Doe, Yasuhiko Arakawa
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Publication number: 20200173848Abstract: A detector includes an active layer containing a quantum well or quantum dots and the detector can shift a detection wavelength by applying a voltage to the active layer. The detector has a reference wavelength to be referred to as a criterion for calibration or correction of the detection wavelength within a range in which the detection wavelength is shifted. A method of calibrating or correcting with the detector, a detection wavelength with the reference wavelength being defined as the criterion is provided.Type: ApplicationFiled: February 10, 2020Publication date: June 4, 2020Inventors: Teruhisa KOTANI, Hirofumi YOSHIKAWA, Tazuko KITAZAWA, Yasuhiko ARAKAWA, Jinkwan KWOEN
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Patent number: 10636833Abstract: A quantum dot infrared detector includes a quantum dot-stacked structure in which quantum dot layers each containing quantum dots stacked on top of one another and intermediate layers. The quantum dots are sandwiched between the intermediate layers in the height direction of the quantum dots. The quantum dots have conduction band quantum confinement levels that include a conduction band ground level, a conduction band first excitation level at a higher energy position than the conduction band ground level, and a conduction band second excitation level at a higher energy position than the conduction band ground level. An energy gap between the conduction band first excitation level and the conduction band bottom of the intermediate layer and an energy gap between the conduction band second excitation level and the conduction band bottom of the intermediate layer are each smaller than twice thermal energy.Type: GrantFiled: September 4, 2018Date of Patent: April 28, 2020Assignees: SHARP KABUSHIKI KAISHA, The University of TokyoInventors: Hirofumi Yoshikawa, Yasuhiko Arakawa
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Publication number: 20190393373Abstract: A high detectivity infrared photodetector is provided. An infrared photodetector 10 includes n-type semiconductor layers 3 and 5 and a photoelectric conversion layer 4. The photoelectric conversion layer 4 includes quantum dots 411, a barrier layer 42, and a single-sided barrier layer 43. The single-sided barrier layer 43 is inserted between the barrier layer 42 and the n-type semiconductor layer 5 and has a wider band gap than does the barrier layer 42. Letting y be an energy level difference between the bottom of the conduction band of the single-sided barrier layer 43 and the bottom of the conduction band of the n-type semiconductor layer 5, z be a voltage in volts applied to the photoelectric conversion layer 4, and d be a thickness in nanometers of the photoelectric conversion layer 4, the infrared photodetector 10 satisfies y?27×exp(0.64×z/(d×10000)).Type: ApplicationFiled: June 14, 2019Publication date: December 26, 2019Inventors: Hirofumi YOSHIKAWA, Takahiro DOE, Yasuhiko ARAKAWA
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Publication number: 20190301944Abstract: An infrared photodetection system is provided that is capable of measuring infrared light up to high-temperature regions while improving a temperature resolution for low-temperature regions without increasing image-acquisition time even if the measuring temperature range varies. The infrared photodetection system is set up to exhibit sensitivity spectrum SSP1 for high sensitivity (for low temperature use) and sensitivity spectrum SSP2 for low sensitivity (for high temperature use) in the transmission band of the bandpass filter when different voltages are applied to a quantum-dot infrared photodetector. The infrared photodetection system then integrates temperature data for the infrared light detected using sensitivity spectrum SSP1 and temperature data for the infrared light detected using sensitivity spectrum SSP2, in order to output a temperature distribution in a measurement region.Type: ApplicationFiled: March 28, 2019Publication date: October 3, 2019Inventors: Takahiro DOE, Hirofumi YOSHIKAWA, Tazuko KITAZAWA, Yasuhiko ARAKAWA
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Publication number: 20190074320Abstract: A quantum dot infrared detector includes a quantum dot-stacked structure in which quantum dot layers each containing quantum dots stacked on top of one another and intermediate layers. The quantum dots are sandwiched between the intermediate layers in the height direction of the quantum dots. The quantum dots have conduction band quantum confinement levels that include a conduction band ground level, a conduction band first excitation level at a higher energy position than the conduction band ground level, and a conduction band second excitation level at a higher energy position than the conduction band ground level. An energy gap between the conduction band first excitation level and the conduction band bottom of the intermediate layer and an energy gap between the conduction band second excitation level and the conduction band bottom of the intermediate layer are each smaller than twice thermal energy.Type: ApplicationFiled: September 4, 2018Publication date: March 7, 2019Inventors: HIROFUMI YOSHIKAWA, YASUHIKO ARAKAWA
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Patent number: 10181539Abstract: A photoelectric conversion element includes a buffer layer, a BSF layer, a base layer, a photoelectric conversion layer, an emitter layer, a window layer, a contact layer, and a p-type electrode sequentially on one surface of a substrate, and includes an n-type electrode on the other surface of the substrate. The photoelectric conversion layer has at least one quantum dot layer. The at least one quantum dot layer includes a quantum dot and a barrier layer. A photoelectric conversion member including the buffer layer, the BSF layer, the base layer, the photoelectric conversion layer, the emitter layer, the window layer, and the contact layer has an edge of incidence that receives light in an oblique direction relative to the growth direction of the quantum dot. A concentrator concentrates sunlight and causes the concentrated sunlight to enter the photoelectric conversion member from the edge of incidence.Type: GrantFiled: June 26, 2017Date of Patent: January 15, 2019Assignees: SHARP KABUSHIKI KAISHA, THE UNIVERSITY OF TOKYOInventors: Hirofumi Yoshikawa, Makoto Izumi, Yasuhiko Arakawa, Takeo Kageyama
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Publication number: 20180331240Abstract: A quantum dot infrared detector includes a photoelectric conversion layer. The photoelectric conversion layer includes a quantum dot stacked structure in which quantum dot layers are stacked, each quantum dot layer including at least quantum dots, a underlayer for the quantum dots, and a partial cap layer at least partially covering the quantum dots. The underlayer is AlxGa1-xAs (0?x<1), and the partial cap layer is AlyGa1-yAs (0?y<1). When the lower of x and y is represented by z and a size of the quantum dots in a direction perpendicular to a stacking direction of the quantum dot stacked structure is represented by R (nm), z satisfies z?0.14×R?1.6, and the size of the quantum dots in the stacking direction is less than or equal to 0.5R.Type: ApplicationFiled: May 10, 2018Publication date: November 15, 2018Inventors: HIROFUMI YOSHIKAWA, Makoto Izumi, TAZUKO KITAZAWA, TERUHISA KOTANI, YASUHIKO ARAKAWA
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Publication number: 20180172508Abstract: A detector includes an active layer containing a quantum well or quantum dots and the detector can shift a detection wavelength by applying a voltage to the active layer. The detector has a reference wavelength to be referred to as a criterion for calibration or correction of the detection wavelength within a range in which the detection wavelength is shifted. A method of calibrating or correcting with the detector, a detection wavelength with the reference wavelength being defined as the criterion is provided.Type: ApplicationFiled: December 15, 2017Publication date: June 21, 2018Inventors: Teruhisa KOTANI, Hirofumi YOSHIKAWA, Tazuko KITAZAWA, Yasuhiko ARAKAWA, Jinkwan KWOEN
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Publication number: 20180006174Abstract: A photoelectric conversion element includes a buffer layer, a BSF layer, a base layer, a photoelectric conversion layer, an emitter layer, a window layer, a contact layer, and a p-type electrode sequentially on one surface of a substrate, and includes an n-type electrode on the other surface of the substrate. The photoelectric conversion layer has at least one quantum dot layer. The at least one quantum dot layer includes a quantum dot and a barrier layer. A photoelectric conversion member including the buffer layer, the BSF layer, the base layer, the photoelectric conversion layer, the emitter layer, the window layer, and the contact layer has an edge of incidence that receives light in an oblique direction relative to the growth direction of the quantum dot. A concentrator concentrates sunlight and causes the concentrated sunlight to enter the photoelectric conversion member from the edge of incidence.Type: ApplicationFiled: June 26, 2017Publication date: January 4, 2018Inventors: Hirofumi YOSHIKAWA, Makoto IZUMI, Yasuhiko ARAKAWA, Takeo KAGEYAMA