Patents by Inventor Kohji Sakai

Kohji Sakai 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).

  • Patent number: 11740453
    Abstract: An apparatus configured to fly a light-absorbing material, includes a unit configured to irradiate a light-absorbing material absorbing light with a laser beam corresponding to a light absorption wavelength of the light-absorbing material to fly the light-absorbing material. When a preceding beam radiation region and a following beam radiation region overlap, the following beam radiation region is irradiated with the laser beam such that a beam centroid position is outside the preceding beam radiation region.
    Type: Grant
    Filed: May 29, 2020
    Date of Patent: August 29, 2023
    Assignee: RICOH COMPANY, LTD.
    Inventors: Hiroyuki Suhara, Takashi Fujita, Atsushi Takeuchi, Kohji Sakai, Asato Tamura, Shohta Kobashigawa
  • Publication number: 20210339469
    Abstract: An apparatus configured to model a three-dimensional modeled object, includes a carrier, an energy applying unit, and a flying unit. The carrier is configured to carry a modeling material. The energy applying unit is configured to apply energy to a surface of a modeled object. The flying unit is configured to fly the modeling material carried on the carrier toward the surface of the modeled object, the energy being applied to the surface.
    Type: Application
    Filed: July 16, 2021
    Publication date: November 4, 2021
    Applicant: Ricoh Company, Ltd.
    Inventors: Takashi FUJITA, Hiroyuki SUHARA, Kohji SAKAI, Shohta KOBASHIGAWA, Atsushi TAKEUCHI, Asato TAMURA, Ichiro MAEDA, Takuei NISHIO
  • Patent number: 11150345
    Abstract: First and second types of object detectors, a sensing device, and a mobile apparatus. The first and second types of object detectors include a light source configured to emit light, photoreceptor configured to receive the light reflected by an object, and a binarizing circuit configured to binarize a signal sent from the photoreceptor at a threshold Vth. In the first and second types of object detectors, object detection processes are performed in a same direction until a high-level signal is output M times from the signal binarized by the binarizing circuit. In the first type of object detector, a value of the M is determined based on an incidence of shot noise where peak intensity exceeds the threshold Vth in the photoreceptor. In the second type of object detector, a threshold Vth is set based on a value of the M.
    Type: Grant
    Filed: August 2, 2018
    Date of Patent: October 19, 2021
    Assignee: RICOH COMPANY, LTD.
    Inventors: Kohji Sakai, Toshishige Fujii, Tadashi Nakamura, Takeshi Ueda, Kohei Ushio, Yuuta Yoshino
  • Publication number: 20210041677
    Abstract: An irradiation optical system includes a light source unit and an irradiation unit. The irradiation unit is configured to condense light from the light source unit onto an irradiated surface to irradiate the irradiated surface with the light. In the irradiation unit, a direction of an optical axis is a Z direction, two directions orthogonal to the optical axis and orthogonal to each other are an X direction and a Y direction, and a positive power in the X direction is set to be smaller than a positive power in the Y direction such that a condensing spot on an X-Y plane at a position where the light from the light source unit is condensed has an elliptical shape having the X direction as a major axis.
    Type: Application
    Filed: July 28, 2020
    Publication date: February 11, 2021
    Inventors: Hirotoshi NAKAYAMA, Kohji SAKAI
  • Publication number: 20200379251
    Abstract: An apparatus configured to fly a light-absorbing material, includes a unit configured to irradiate a light-absorbing material absorbing light with a laser beam corresponding to a light absorption wavelength of the light-absorbing material to fly the light-absorbing material. When a preceding beam radiation region and a following beam radiation region overlap, the following beam radiation region is irradiated with the laser beam such that a beam centroid position is outside the preceding beam radiation region.
    Type: Application
    Filed: May 29, 2020
    Publication date: December 3, 2020
    Applicant: Ricoh Company, Ltd.
    Inventors: Hiroyuki SUHARA, Takashi FUJITA, Atsushi TAKEUCHI, Kohji SAKAI, Asato TAMURA, Shohta KOBASHIGAWA
  • Patent number: 10700491
    Abstract: A semiconductor laser is for generating colored light. The semiconductor laser oscillates in a longitudinal multimode. A width of a wavelength band with an intensity equal to or more than ?20 dB relative to a peak intensity in a spectrum distribution of output light is equal to or less than 15 nm. A light source device may include The semiconductor laser; a wavelength estimating device configured to estimate a wavelength ? of light from the semiconductor laser; and an emission-light intensity setting unit configured to set an emission light intensity of the semiconductor laser in accordance with an estimation result by the wavelength estimating device.
    Type: Grant
    Filed: April 19, 2017
    Date of Patent: June 30, 2020
    Assignee: RICOH COMPANY, LTD.
    Inventors: Kohji Sakai, Miho Higuchi
  • Patent number: 10591602
    Abstract: An object detector includes a projector including a light source having a two-dimensionally arranged plurality of light emitter groups, each of the light emitter groups having a plurality of light emitters, a light receiver which receives light emitted from the projector, and reflected by an object, and a light source driver which lights on and lights off each of the light emitter groups of the light source.
    Type: Grant
    Filed: April 15, 2019
    Date of Patent: March 17, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiro Akatsu, Tadashi Nakamura, Kohji Sakai
  • Patent number: 10534112
    Abstract: A microlens array includes N lenses ranging from a 1st lens to an Nth lens and a lens arrangement area. N is a positive integer. The lens arrangement area has the N lenses arranged in array. The lens arrangement area receives light emitted from a light source. An ith (i being 1st to Nth) lens satisfies a conditional expression below: ?20°???20° where ? denotes an angle formed by a main-axis orientation of double refraction and a reference orientation.
    Type: Grant
    Filed: December 21, 2018
    Date of Patent: January 14, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohji Sakai, Miho Higuchi, Jun Watanabe
  • Publication number: 20190242997
    Abstract: An object detector includes a projector including a light source having a two-dimensionally arranged plurality of light emitter groups, each of the light emitter groups having a plurality of light emitters, a light receiver which receives light emitted from the projector, and reflected by an object, and a light source driver which lights on and lights off each of the light emitter groups of the light source.
    Type: Application
    Filed: April 15, 2019
    Publication date: August 8, 2019
    Inventors: Kazuhiro AKATSU, Tadashi NAKAMURA, Kohji SAKAI
  • Patent number: 10371817
    Abstract: An object detecting apparatus includes: a light projection unit that is an array light source in which each of a plurality of light emission areas emits light, an optical scanning unit that performs scanning with the light, which is emitted from the light projection unit, in a first direction, and a light receiving unit that receives reflected light which is the light, with which the scanning is performed, being reflected by an object, and an object information acquiring unit that detects presence/absence of the object based on emission timing at which the light is emitted from the light projection unit and light receiving timing at which the light receiving unit receives the reflected light.
    Type: Grant
    Filed: June 6, 2018
    Date of Patent: August 6, 2019
    Assignee: RICOH COMPANY, LTD.
    Inventors: Kohji Sakai, Tadashi Nakamura
  • Patent number: 10302767
    Abstract: An object detector includes a projector including a light source having a two-dimensionally arranged plurality of light emitter groups, each of the light emitter groups having a plurality of light emitters, a light receiver which receives light emitted from the projector, and reflected by an object, and a light source driver which lights on and lights off each of the light emitter groups of the light source.
    Type: Grant
    Filed: October 10, 2017
    Date of Patent: May 28, 2019
    Assignee: RICOH COMPANY, LTD.
    Inventors: Kazuhiro Akatsu, Tadashi Nakamura, Kohji Sakai
  • Patent number: 10302942
    Abstract: A light-source device including a light-emitting element to emit light, a light-receiving system, an acquisition unit, a setting unit, and an adjuster. The light-receiving system receives the light emitted from the light emitting element. The acquisition unit acquires a wavelength of the light emitted from the light emitting element. The setting unit sets a target value of an amount of the light received by the light-receiving system based on the wavelength acquired by the acquisition unit. The adjuster adjusts an amount of the light emitted from the light emitting element such that the amount of the light reaches the target value of the light that is set with the setting unit.
    Type: Grant
    Filed: August 25, 2017
    Date of Patent: May 28, 2019
    Assignee: Ricoh Company, Ltd.
    Inventor: Kohji Sakai
  • Publication number: 20190121002
    Abstract: A microlens array includes N lenses ranging from a 1st lens to an Nth lens and a lens arrangement area. N is a positive integer. The lens arrangement area has the N lenses arranged in array. The lens arrangement area receives light emitted from a light source. An ith (i being 1st to Nth) lens satisfies a conditional expression below: ?20°???20° where ? denotes an angle formed by a main-axis orientation of double refraction and a reference orientation.
    Type: Application
    Filed: December 21, 2018
    Publication date: April 25, 2019
    Inventors: Kohji SAKAI, Miho HIGUCHI, Jun WATANABE
  • Publication number: 20190097396
    Abstract: A semiconductor laser is for generating colored light. The semiconductor laser oscillates in a longitudinal multimode. A width of a wavelength band with an intensity equal to or more than ?20 dB relative to a peak intensity in a spectrum distribution of output light is equal to or less than 15 nm. A light source device may include The semiconductor laser; a wavelength estimating device configured to estimate a wavelength ? of light from the semiconductor laser; and an emission-light intensity setting unit configured to set an emission light intensity of the semiconductor laser in accordance with an estimation result by the wavelength estimating device.
    Type: Application
    Filed: April 19, 2017
    Publication date: March 28, 2019
    Inventors: Kohji SAKAI, Miho HIGUCHI
  • Publication number: 20190056496
    Abstract: First and second types of object detectors, a sensing device, and a mobile apparatus. The first and second types of object detectors include a light source configured to emit light, photoreceptor configured to receive the light reflected by an object, and a binarizing circuit configured to binarize a signal sent from the photoreceptor at a threshold Vth. In the first and second types of object detectors, object detection processes are performed in a same direction until a high-level signal is output M times from the signal binarized by the binarizing circuit. In the first type of object detector, a value of the M is determined based on an incidence of shot noise where peak intensity exceeds the threshold Vth in the photoreceptor. In the second type of object detector, a threshold Vth is set based on a value of the M.
    Type: Application
    Filed: August 2, 2018
    Publication date: February 21, 2019
    Inventors: Kohji SAKAI, Toshishige FUJII, Tadashi NAKAMURA, Takeshi UEDA, Kohei USHIO, Yuuta YOSHINO
  • Patent number: 10209133
    Abstract: A wavelength estimation device including a light detector to receive light emitted from a light source and an estimation unit. The estimation unit estimates a wavelength of the light based on an amount of light received by the light detector.
    Type: Grant
    Filed: March 9, 2017
    Date of Patent: February 19, 2019
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohji Sakai, Kazuhiro Akatsu
  • Patent number: 10203431
    Abstract: A microlens array includes N lenses ranging from a 1st lens to an Nth lens and a lens arrangement area. N is a positive integer. The lens arrangement area has the N lenses arranged in array. The lens arrangement area receives light emitted from a light source. An ith (i being 1st to Nth) lens satisfies a conditional expression below: ?20°???20° where ? denotes an angle formed by a main-axis orientation of double refraction and a reference orientation.
    Type: Grant
    Filed: September 28, 2017
    Date of Patent: February 12, 2019
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohji Sakai, Miho Higuchi, Jun Watanabe
  • Patent number: 10148064
    Abstract: A semiconductor laser driving apparatus for driving a semiconductor laser serving as a light source for optical scanning, the semiconductor laser driving apparatus includes: first and second switching elements that are each capable of switching energization of the semiconductor laser ON/OFF; a first pulse generation unit that intermittently outputs first driving pulses to the first switching element in a first time slot; and a second pulse generation unit that outputs a second driving pulse to the second switching element in a second time slot different from the first time slot.
    Type: Grant
    Filed: March 2, 2016
    Date of Patent: December 4, 2018
    Assignee: RICOH COMPANY, LTD
    Inventors: Kohji Sakai, Masataka Uehira, Shigeaki Imai, Tadashi Nakamura
  • Patent number: 10132926
    Abstract: A range finder which irradiates a subject by emission of a light source, and receives reflected light from the subject so as to measure a distance to the subject, the range finder includes a plurality of light-source-driving circuits supplying a driving current to the light source when a light-emitting signal that controls the emission of the light source is input, wherein the light-emitting signal is output to one of the light-source-driving circuits, and each of the light-source-driving circuits has a different response speed to the light-emitting signal.
    Type: Grant
    Filed: March 16, 2015
    Date of Patent: November 20, 2018
    Assignee: RICOH COMPANY, LTD.
    Inventors: Masataka Uehira, Atsufumi Omori, Kohji Sakai
  • Publication number: 20180290476
    Abstract: A light irradiation apparatus includes an irradiation unit including a light source to emit light to a process-target object, a light source driving circuit to drive the light source, a light source controller to control the light source driving circuit to change a light output level of the light source, and a light spot controller to control energy or energy density of a beam spot of the light on the process-target object depending on an operation mode, and a transition mode that one operation mode is being changed to another mode. The light spot controller sets the energy or energy density during the transition mode lower compared to either of the energy or energy density during the one operation mode before the transition mode and the energy or energy density during the another mode after the transition mode.
    Type: Application
    Filed: June 15, 2018
    Publication date: October 11, 2018
    Inventors: Masataka UEHIRA, Kohji SAKAI, Tomoyasu HIRASAWA, Tomomi ISHIMI