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: 9435938
    Abstract: LED light source substrates (140) in an edge-light type surface light source device are disposed with a light guide plate interposed therebetween. A length of each of the LED light source substrates is shorter than a length of a plane of incidence of the light guide plate. The chromaticity of light from a central part (141) is uniform, and the chromaticity of light from ends (142) is more shifted toward blue than the chromaticity of light from the central part (141).
    Type: Grant
    Filed: September 18, 2013
    Date of Patent: September 6, 2016
    Assignee: SHARP KABUSHIKI KAISHA
    Inventors: Atsushi Yamashita, Kohji Sakai
  • Publication number: 20160096474
    Abstract: An object detector is provided including a light emitter including at least a light source having a plurality of light emitting areas disposed along a first direction to emit light, an optical scanner configured to scan the light emitted from the light emitter along a second direction that is different from the first direction, a light receiver configured to receive the light that is scanned by the optical scanner and then is reflected at an object, and a controller configured to divide a detection field into a plurality of subareas in a third direction that is orthogonal to the second direction, where a number of partitions of the detection field is variable.
    Type: Application
    Filed: August 27, 2015
    Publication date: April 7, 2016
    Inventor: Kohji SAKAI
  • Publication number: 20160061955
    Abstract: An optical scanner is provided including a light source configured to emit light, a light source driving device configured to drive the light source, a light deflector having at least one rotating reflection plane and configured to deflect the light emitted from the light source to a scanning area, and a light detector configured to output a signal to control a timing at which scanning of the scanning area by the light deflected by the light deflector starts, where the light detector and the scanning area are sequentially scanned in a single scanning by one reflection plane of the light deflector, and the light source driving device drives the light source using a first driving method when the light scans the light detector, and drives the light source using a second driving method that is different from the first driving method when the light scans the scanning area.
    Type: Application
    Filed: July 30, 2015
    Publication date: March 3, 2016
    Inventors: Shigeaki Imai, Masataka Uehira, Kohji Sakai, Tadashi Nakamura, Yukio Itami
  • Patent number: 9235154
    Abstract: An image forming method includes: exposing a surface of an image carrier with a light based on an image pattern including an image portion and a non-image portion to form an electrostatic latent image corresponding to the image pattern. The image portion is made up of a plurality of pixels. Some of the pixels that make up the image portion are exposed with light of a first output value that is higher than a prescribed optical output value when the entire pixels corresponding to the image portion are exposed over a prescribed time period.
    Type: Grant
    Filed: August 5, 2014
    Date of Patent: January 12, 2016
    Assignee: RICOH COMPANY, LIMITED
    Inventors: Hiroyuki Suhara, Hiroaki Tanaka, Kohji Sakai
  • Publication number: 20150346484
    Abstract: An optical scanning device includes: a light source that emits a laser beam modulated and driven according to an image forming signal; a scanning optical system that includes a polygon mirror to scan a surface of a photoconductor with the laser beam from the light source; a surface identifying unit that associates a sub-scanning position by the polygon mirror with each surface of the polygon mirror; and a light-amount adjusting unit that adjusts a light amount of the light source according to the sub-scanning position, for each surface of the polygon mirror.
    Type: Application
    Filed: May 27, 2015
    Publication date: December 3, 2015
    Inventors: Mitsuo SUZUKI, Kohji SAKAI
  • Publication number: 20150268343
    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: Application
    Filed: March 16, 2015
    Publication date: September 24, 2015
    Inventors: Masataka UEHIRA, Atsufumi Omori, Kohji Sakai
  • Publication number: 20150226911
    Abstract: LED light source substrates (140) in an edge-light type surface light source device are disposed with a light guide plate interposed therebetween. A length of each of the LED light source substrates is shorter than a length of a plane of incidence of the light guide plate. The chromaticity of light from a central part (141) is uniform, and the chromaticity of light from ends (142) is more shifted toward blue than the chromaticity of light from the central part (141).
    Type: Application
    Filed: September 18, 2013
    Publication date: August 13, 2015
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Atsushi Yamashita, Kohji Sakai
  • Publication number: 20150204977
    Abstract: An object detection device includes: a light projection unit that includes a light source having a plurality of light emitting units that are arranged along at least one direction; a light scanning unit that scans light emitted from the light projection unit along the one direction; a light receiving unit that receives light emitted from the light scanning unit and reflected on an object; and a control unit that determines a light emitting unit to be turned on among the light emitting units, according to a direction of travel of light scanned by the light scanning unit.
    Type: Application
    Filed: January 20, 2015
    Publication date: July 23, 2015
    Inventor: Kohji SAKAI
  • Publication number: 20150160341
    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: November 26, 2014
    Publication date: June 11, 2015
    Inventors: Kazuhiro AKATSU, Tadashi Nakamura, Kohji Sakai
  • Publication number: 20150124238
    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: Application
    Filed: October 24, 2014
    Publication date: May 7, 2015
    Inventors: Kohji Sakai, Tadashi Nakamura
  • Publication number: 20150042740
    Abstract: An image forming method includes: exposing a surface of an image carrier with a light based on an image pattern including an image portion and a non-image portion to form an electrostatic latent image corresponding to the image pattern. The image portion is made up of a plurality of pixels. Some of the pixels that make up the image portion are exposed with light of a first output value that is higher than a prescribed optical output value when the entire pixels corresponding to the image portion are exposed over a prescribed time period.
    Type: Application
    Filed: August 5, 2014
    Publication date: February 12, 2015
    Inventors: Hiroyuki SUHARA, Hiroaki TANAKA, Kohji Sakai
  • Patent number: 8922863
    Abstract: An optical scanning device separately scanning plural scan target surfaces in a first direction with light includes: a light source unit configured to emit first and second light beams mutually different in polarization state; an optical deflector configured to rotate around an axis parallel to a second direction perpendicular to the first direction, and deflect the emitted light beams; an imaging optical element provided on respective optical paths of the deflected light beams; a polarization adjustment element provided on the optical paths of the light beams transmitted through the imaging optical element, and configured to correct respective changes in polarization state of the light beams occurring during the transmission of the light beams through the imaging optical element; and a polarization separation element provided on the optical paths of the light beams emitted from the polarization adjustment element, and configured to separate the light beams from each other.
    Type: Grant
    Filed: September 10, 2012
    Date of Patent: December 30, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Toshiaki Tokita, Nobuaki Kubo, Naoto Watanabe, Kohji Sakai
  • Publication number: 20140368768
    Abstract: In the present invention, a backlight (3) serving as a planar light source unit is equipped with: multiple LEDs (12); and a bottom plate (11a) having a mounting surface (11a1). The multiple LEDs (12) are two-dimensionally arranged on the mounting surface (11a1) within a rectangular area (RA) that is smaller than the bottom plate (11a). In addition, the arrangement density of the LEDs in the rectangular area (RA) is lower at the center part (Rc) than at the peripheral part (Rp). The rectangular area (RA) has a corner area, where at least one LED (12) is provided, at each of the four corners thereof. The LEDs (12) positioned in the respective corner areas are installed such that the central axes of the LEDs lean toward the periphery side of the rectangular area (RA) with respect to the direction perpendicular to the mounting surface (11a1).
    Type: Application
    Filed: December 20, 2012
    Publication date: December 18, 2014
    Inventor: Kohji Sakai
  • Patent number: 8913096
    Abstract: An optical scanning device that scans a scanning surface in a main scanning direction. The device includes a surface emitting laser as a light source, an optical deflector that deflects a light flux from the light source while rotating around a rotation axis, a monitor light receiving element, a synchronization detection light receiving element, a monitor optical system that directs the monitor light flux to the monitor light receiving element, a synchronization detection optical system that directs the synchronization detection light flux to the synchronization detection light receiving element, and a scanning optical system that directs a scanning light flux to the scanning surface. A combined focal length of the monitor optical system in the main scanning direction is smaller than a combined focal length of the synchronization detection optical system in the main scanning direction.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: December 16, 2014
    Assignee: Ricoh Company, Limited
    Inventor: Kohji Sakai
  • Patent number: 8848009
    Abstract: An optical scanning device scanning scan target surfaces in a first direction with light includes: a light source emitting first and second light beams corresponding to two of the scan target surfaces; an optical deflector including a reflection surface on which the emitted first and second light beams are obliquely incident while being separated from each other in a second direction perpendicular to the first direction, and deflecting the first and second light beams; a scanning lens disposed on respective optical paths of the deflected first and second light beams; and a branching optical element transmitting therethrough most of the first light beam transmitted through the scanning lens, and reflecting most of the second light beam transmitted through the scanning lens. The deflected first and second light beams intersect between the optical deflector and the branching optical element, when projected on a plane perpendicular to the first direction.
    Type: Grant
    Filed: September 21, 2012
    Date of Patent: September 30, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Naoto Watanabe, Toshiaki Tokita, Kohji Sakai, Nobuaki Kubo
  • Patent number: 8786658
    Abstract: An exposure device to expose an exposure element includes a light source; an optical system to guide light emitted from the light source to the exposure element; and an optical housing, configured with a plurality of plates, to support the light source and the optical system. At least one of the plurality of plates configuring the optical housing is formed with a plurality of grooves on each of a first face and a second face with a given pitch on the one of the plurality of plates, the first face and the second face being opposite faces with each other. The plurality of grooves are arranged by shifting the center of each of grooves formed on the first face and the center of each of grooves formed on the second face.
    Type: Grant
    Filed: March 4, 2013
    Date of Patent: July 22, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Nobuaki Kubo, Toshiaki Tokita, Kohji Sakai, Naoto Watanabe, Tomohiro Nakajima, Yorichika Ishiyama
  • Publication number: 20130250029
    Abstract: An exposure device to expose an exposure element includes a light source; an optical system to guide light emitted from the light source to the exposure element; and an optical housing, configured with a plurality of plates, to support the light source and the optical system. At least one of the plurality of plates configuring the optical housing is formed with a plurality of grooves on each of a first face and a second face with a given pitch on the one of the plurality of plates, the first face and the second face being opposite faces with each other. The plurality of grooves are arranged by shifting the center of each of grooves formed on the first face and the center of each of grooves formed on the second face.
    Type: Application
    Filed: March 4, 2013
    Publication date: September 26, 2013
    Inventors: Nobuaki KUBO, Toshiaki Tokita, Kohji Sakai, Naoto Watanabe, Tomohiro Nakajima, Yorichika Ishiyama
  • Publication number: 20130155166
    Abstract: An optical scanning apparatus includes a light source, an optical deflector having a rotary polygon mirror to deflect a light beam from the light source, a scanning optical system configured to focus the light beam deflected by the optical deflector on a target surface, a sync detecting sensor configured to determine a write start timing on the target surface, and a processing unit configured to correct detection data of the sync detecting sensor based on a measured value of a time needed for one revolution of the rotary polygon mirror.
    Type: Application
    Filed: December 18, 2012
    Publication date: June 20, 2013
    Inventors: Naoto WATANABE, Toshiaki TOKITA, Kohji SAKAI, Nobuaki KUBO, Masayuki MURANAKA
  • Patent number: 8441513
    Abstract: A light source device includes a surface emitting laser, a surface emitting laser holding unit on which the surface emitting laser is mounted, a parallel plate that is arranged on a light path of a light flux from the surface emitting laser so that the light flux enters into one surface thereof, and that is made of a transparent material, and a holder having a through hole that functions as a light path of the light flux from the surface emitting laser, wherein the surface emitting laser holding unit is brought into contact with the holder, the parallel plate is fixedly bonded to the holder, and a part of the through hole of the holder is sealed with the surface emitting laser holding unit and the parallel plate.
    Type: Grant
    Filed: September 14, 2010
    Date of Patent: May 14, 2013
    Assignee: Ricoh Company, Ltd.
    Inventor: Kohji Sakai
  • Patent number: RE45918
    Abstract: F-theta lenses, included in scanning lens systems, are arranged on a main scanning plane facing an optical deflector and substantially linearly symmetrically on the main scanning plane with reference to a rotational center of the optical deflector. Each f-theta lens has a no-power portion in the main scanning direction. Synchronization-detecting light passes through the no-power portion of the f-theta lens, thus enabling reduction in color shift due to temperature variation in an image forming apparatus without increasing the cost and complexity in controlling color shift.
    Type: Grant
    Filed: December 20, 2012
    Date of Patent: March 8, 2016
    Assignee: RICOH COMPANY, LIMITED
    Inventors: Kenichiroh Saisho, Kohji Sakai