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).

  • Publication number: 20230337449
    Abstract: 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: Application
    Filed: September 28, 2020
    Publication date: October 19, 2023
    Inventors: HIROFUMI YOSHIKAWA, TAKAHIRO DOE, Masaki YAMAMOTO
  • Publication number: 20230276649
    Abstract: 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: Application
    Filed: July 22, 2020
    Publication date: August 31, 2023
    Inventors: HIROFUMI YOSHIKAWA, YOSHIHIRO UETA, TAKAHIRO DOE, Masaki YAMAMOTO, DAISUKE TOYOSHIMA
  • Publication number: 20230136993
    Abstract: 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: Application
    Filed: February 4, 2020
    Publication date: May 4, 2023
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: HIROFUMI YOSHIKAWA, TATSUYA RYOHWA, Masaki YAMAMOTO, TAKAHIRO DOE
  • Publication number: 20220344606
    Abstract: 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: Application
    Filed: October 2, 2019
    Publication date: October 27, 2022
    Inventors: HIROFUMI YOSHIKAWA, TATSUYA RYOHWA, Masumi KUBO, TAKAHIRO DOE, Masaki YAMAMOTO
  • Publication number: 20220320191
    Abstract: 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: Application
    Filed: October 2, 2019
    Publication date: October 6, 2022
    Inventors: HIROFUMI YOSHIKAWA, TATSUYA RYOHWA, Masumi KUBO, TAKAHIRO DOE, Masaki YAMAMOTO
  • Publication number: 20220165973
    Abstract: 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: Application
    Filed: March 11, 2019
    Publication date: May 26, 2022
    Inventors: HIROFUMI YOSHIKAWA, TATSUYA RYOHWA, Masaki YAMAMOTO, TAKAHIRO DOE
  • Publication number: 20220158108
    Abstract: 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: Application
    Filed: February 27, 2019
    Publication date: May 19, 2022
    Inventors: HIROFUMI YOSHIKAWA, TATSUYA RYOHWA, Masaki YAMAMOTO, TAKAHIRO DOE
  • Publication number: 20210296517
    Abstract: 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: Application
    Filed: March 11, 2021
    Publication date: September 23, 2021
    Inventors: HIROFUMI YOSHIKAWA, YASUHIKO ARAKAWA
  • Patent number: 10866143
    Abstract: 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: Grant
    Filed: March 28, 2019
    Date of Patent: December 15, 2020
    Assignees: SHARP KABUSHIKI KAISHA, THE UNIVERSITY OF TOKYO
    Inventors: Takahiro Doe, Hirofumi Yoshikawa, Tazuko Kitazawa, Yasuhiko Arakawa
  • Publication number: 20200378833
    Abstract: 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: Application
    Filed: June 1, 2020
    Publication date: December 3, 2020
    Inventors: HIROFUMI YOSHIKAWA, TAKAHIRO DOE, YASUHIKO ARAKAWA
  • Patent number: 10811554
    Abstract: 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: Grant
    Filed: June 14, 2019
    Date of Patent: October 20, 2020
    Assignees: SHARP KABUSHIKI KAISHA, THE UNIVERSITY OF TOKYO
    Inventors: Hirofumi Yoshikawa, Takahiro Doe, Yasuhiko Arakawa
  • Publication number: 20200173848
    Abstract: 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: Application
    Filed: February 10, 2020
    Publication date: June 4, 2020
    Inventors: Teruhisa KOTANI, Hirofumi YOSHIKAWA, Tazuko KITAZAWA, Yasuhiko ARAKAWA, Jinkwan KWOEN
  • Patent number: 10636833
    Abstract: 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: Grant
    Filed: September 4, 2018
    Date of Patent: April 28, 2020
    Assignees: SHARP KABUSHIKI KAISHA, The University of Tokyo
    Inventors: Hirofumi Yoshikawa, Yasuhiko Arakawa
  • Publication number: 20190393373
    Abstract: 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: Application
    Filed: June 14, 2019
    Publication date: December 26, 2019
    Inventors: Hirofumi YOSHIKAWA, Takahiro DOE, Yasuhiko ARAKAWA
  • Publication number: 20190301944
    Abstract: 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: Application
    Filed: March 28, 2019
    Publication date: October 3, 2019
    Inventors: Takahiro DOE, Hirofumi YOSHIKAWA, Tazuko KITAZAWA, Yasuhiko ARAKAWA
  • Publication number: 20190074320
    Abstract: 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: Application
    Filed: September 4, 2018
    Publication date: March 7, 2019
    Inventors: HIROFUMI YOSHIKAWA, YASUHIKO ARAKAWA
  • Patent number: 10181539
    Abstract: 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: Grant
    Filed: June 26, 2017
    Date of Patent: January 15, 2019
    Assignees: SHARP KABUSHIKI KAISHA, THE UNIVERSITY OF TOKYO
    Inventors: Hirofumi Yoshikawa, Makoto Izumi, Yasuhiko Arakawa, Takeo Kageyama
  • Publication number: 20180331240
    Abstract: 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: Application
    Filed: May 10, 2018
    Publication date: November 15, 2018
    Inventors: HIROFUMI YOSHIKAWA, Makoto Izumi, TAZUKO KITAZAWA, TERUHISA KOTANI, YASUHIKO ARAKAWA
  • Publication number: 20180172508
    Abstract: 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: Application
    Filed: December 15, 2017
    Publication date: June 21, 2018
    Inventors: Teruhisa KOTANI, Hirofumi YOSHIKAWA, Tazuko KITAZAWA, Yasuhiko ARAKAWA, Jinkwan KWOEN
  • Publication number: 20180006174
    Abstract: 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: Application
    Filed: June 26, 2017
    Publication date: January 4, 2018
    Inventors: Hirofumi YOSHIKAWA, Makoto IZUMI, Yasuhiko ARAKAWA, Takeo KAGEYAMA