Patents by Inventor Kouji Oizumi

Kouji Oizumi 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: 5305148
    Abstract: A varifocal lens is disclosed, comprising, from front to rear, a first lens unit of negative power, a second lens unit of positive power, and a third lens unit of negative power, all these lenses being moved along a common optical axis when the focal length of the entire lens system varies, wherein all the lens units each are constructed with either one lens, or two lenses, the total number of lenses being limited to 3 or 4, while still maintaining good optical performance.
    Type: Grant
    Filed: January 12, 1993
    Date of Patent: April 19, 1994
    Assignee: Canon Kabushiki Kaisha
    Inventors: Keiji Ikemori, Kouji Oizumi, Yoshinori Itoh
  • Patent number: 5270866
    Abstract: A zoom lens comprising, from front to rear, a first lens unit of negative power, a second lens unit of positive power and a third lens unit of negative power, the second and third lens units being moved to effect zooming, and the third lens unit having its focal length f.sub.3 laid in the following range:0.5 f.sub.W <.vertline.f.sub.3 .vertline.<4 f.sub.Twhere f.sub.W and f.sub.T are the shortest and longest focal lengths of the entire system.
    Type: Grant
    Filed: November 26, 1991
    Date of Patent: December 14, 1993
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kouji Oizumi, Keiji Ikemori, Yasuhisa Sato, Yasuyuki Yamada, Hiroki Nakayama, Takashi Matsushita
  • Patent number: 5270857
    Abstract: An image stabilizing system includes a photographic lens device having a plurality of lens units, wherein for zooming at least one lens unit separation varies, a detecting circuit for detecting the jiggle of the system, and a drive device for driving at least one lens unit in a direction perpendicular to a photographic optical axis of the photographic lens device on the basis of an output of the detecting circuit to stabilize an image.
    Type: Grant
    Filed: October 24, 1988
    Date of Patent: December 14, 1993
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kouji Oizumi, Nozomu Kitagishi, Shoichi Yamzaki
  • Patent number: 5253005
    Abstract: A small-sized camera in which while the light emerging from a photographic lens having an optical axis parallel with a photosensitive plane is conducted by first and second mirrors to the photosensitive plane to form a photographic system, the first or second mirror is turned around a predetermined axis to conduct the light to an eyepiece lens to form a finder system. And, a structure of construction for efficiently removing the stray light of this camera is disclosed.
    Type: Grant
    Filed: December 12, 1991
    Date of Patent: October 12, 1993
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takeshi Koyama, Sadatoshi Takahashi, Nozomu Kitagishi, Kouji Oizumi
  • Patent number: 5125735
    Abstract: A distance measuring device has a light source for emitting a plurality of light beams in a plurality of directions, and a light receiving lens having a plurality of optical axes for receiving the plurality of light beams reflected from objects in said plurality of directions. Light receiving apparatus is provided for receiving the reflected light beams passing through said light receiving lens and providing an output corresponding to distances to the object. The light receiving lens has (1) a central portion with a thickness (D), a focal length f.sub.a, and a refractive index .phi..sub.A, and (2) a second portion adjacent said central portion. Surfaces of said central and second portions closest to said light receiving apparatus comprising one spherical surface having a refractive power .phi..sub.R. the central and second portions being disposed to satisfy the following conditions:0.4<D/f.sub.A <1.5,and-0.05<.phi..sub.R /.phi..sub.A <0.15, .phi..sub.A >0.
    Type: Grant
    Filed: July 27, 1990
    Date of Patent: June 30, 1992
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kouji Oizumi, Takashi Matsushita
  • Patent number: 5055868
    Abstract: A finder device is disclosed comprising a first lens group having a positive refractive power to form a first image, a second lens group having a positive refractive power to re-form the first image, and an eyepiece lens group having a positive refractive power to observe the image the second lens group forms, wherein zooming is performed by moving the first and second lens groups along respective different loci of motion from each other.
    Type: Grant
    Filed: August 8, 1989
    Date of Patent: October 8, 1991
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshinori Itoh, Kouji Oizumi
  • Patent number: 4957356
    Abstract: A finder device capable of forming an erecting non-reverse image to be observed at either of the waist level and the eye level, wherein when used as the waist-level finder, the photographer, while taking his eye at a good distance from the finder, can observe the image of an object to be photographed.
    Type: Grant
    Filed: April 12, 1988
    Date of Patent: September 18, 1990
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kouji Oizumi, Takashi Matsushita
  • Patent number: 4949107
    Abstract: A camera having a photographic lens and an eyepiece lens for observing an image formed by the photographic lens, wherein when this camera is used as a telescope, the interval between the image and the eyepiece lens is shortened, while simultaneously changing the focal length of the eyepiece lens, so that the magnification of the finder is increased.
    Type: Grant
    Filed: August 15, 1989
    Date of Patent: August 14, 1990
    Assignee: Canon Kabushiki Kaisha
    Inventors: Nozomu Kitagishi, Takeshi Koyama, Sadatoshi Takahashi, Kouji Oizumi
  • Patent number: 4871238
    Abstract: A photographic optical device of this invention comprises: a master lens unit having a positive refractive power, determining a photographic optical path and moving along the optical axis to change magnification; a first auxiliary lens unit having a positive refractive power and being capable of being placed on and off the optical path; and a second auxiliary lens unit having a negative refractive power and being capable of being placed on and off the optical path. The first auxiliary lens unit is attached to an image-plane side of the master lens unit to form a photographic unit giving a low ratio of magnification. The second auxiliary lens unit is attached to an image-plane side of the master lens unit to form another photographic unit giving a high ratio of magnification. The first and second auxiliary lens units are placed outside of the optical path to form another photographic unit giving a middle ratio of magnification.
    Type: Grant
    Filed: February 27, 1987
    Date of Patent: October 3, 1989
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuhisa Sato, Yasuyuki Yamada, Hiroki Nakayama, Kouji Oizumi
  • Patent number: 4842395
    Abstract: The disclosed variable magnification finder includes, from front to rear, a first lens unit of negative power, a second lens unit of positive power, a third lens unit of positive power, the first, second and third lens units constituting an objective lens of positive power, and an eyepiece of positive power. The first and second lens units form a finder image on a plane just in front of the third lens unit. The second lens unit is moved axially forward to increase the image magnification, while the shift of diopter of the finder is simultaneously compensated for by moving the first lens unit.
    Type: Grant
    Filed: February 19, 1988
    Date of Patent: June 27, 1989
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuhisa Sato, Nozomu Kitagishi, Yasuyuki Yamada, Hiroki Nakayama, Kouji Oizumi
  • Patent number: 4830474
    Abstract: A changeover type variable magnification optical system whose focal length is changed by locating an auxiliary lens on the image side of a master lens assembly. The system satisfies following inequalities of:0.2<f.sub.2 /f.sub.1 <0.71where f.sub.1 and f.sub.2 are the effective focal lengths of the master lens assembly and the auxiliary lens, respectively. The auxiliary lens is constructed include of at least one aspherical lens surface.
    Type: Grant
    Filed: November 25, 1986
    Date of Patent: May 16, 1989
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hiroki Nakayama, Yasuhisa Sato, Kouji Oizumi, Yasuyuki Yamada
  • Patent number: 4770508
    Abstract: A conversion lens for attachment to the rear of a master lens to increase the focal length of the entire system, includes a positive lens, and a negative lens positioned on the image side of the positive lens, wherein at least one of the lens surfaces of the positive lens and the negative lens is an aspherical surface.
    Type: Grant
    Filed: August 20, 1986
    Date of Patent: September 13, 1988
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuyuki Yamada, Yasuhisa Sato, Hiroki Nakayama, Kouji Oizumi
  • Patent number: 4757336
    Abstract: A view finder having, from front to rear, a first lens unit of negative power, a second lens unit of positive power and a third lens unit of negative power, the second lens unit being moved axially forward as the magnification varies from the smallest to the largest value, while the first lens unit is moved to compensate for the diopter shift resulting from the variation of the magnification.
    Type: Grant
    Filed: January 21, 1986
    Date of Patent: July 12, 1988
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hiroki Nakayama, Yasuhisa Sato, Kouji Oizumi, Yasuyuki Yamada
  • Patent number: 4751539
    Abstract: A variable power finder having an objective lens of positive refracting power comprising a first lens unit of positive refracting power movable along an optical axis and a second lens unit releasably attached to the first lens unit in axial alignment, wherein a real image to be observed is formed by the objective lens.
    Type: Grant
    Filed: July 31, 1987
    Date of Patent: June 14, 1988
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuyuki Yamada, Yasuhisa Sato, Hiroki Nakayama, Kouji Oizumi
  • Patent number: 4726668
    Abstract: In the disclosed zoom lens, a positive front lens unit and a negative rear lens unit are moved forwardly axially in differential relation to vary the overall focal length from a minimum to a maximum value, while a positive middle lens unit is kept stationary during the variation of the focal length. A diaphragm determining the F-number is positioned at a fixed point between the front and rear lens units.
    Type: Grant
    Filed: June 5, 1985
    Date of Patent: February 23, 1988
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hiroki Nakayama, Yasuhisa Sato, Kouji Oizumi, Yasuyuki Yamada
  • Patent number: 4702581
    Abstract: A flash device for a camera having a light emitting window of rectangular shape oriented so that the long side of the window is nearly perpendicular to a long side of the film format in the camera. An optical panel in the light emitting window is constructed in such a way as to satisfy the following conditions:0.5<f1/f<1.5f2/f<0.5,where f1 is the focal length of an end portion of the longitudinal length of the optical panel, f2 is the focal length of a central portion of the optical panel, and f is the focal length of a photographic lens of the camera.
    Type: Grant
    Filed: December 30, 1985
    Date of Patent: October 27, 1987
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuyuki Yamada, Yasuhisa Sato, Hiroki Nakayama, Kouji Oizumi
  • Patent number: 4697882
    Abstract: In the disclosed beam splitter, a first prism has an entrance face, an inclined face, and a mirrored face for totally reflecting a beam reflected from the inclined face back to the inclined face. A second prism has an entrance face in parallel with the inclined face of the first prism, and two exit faces. One of the exit faces of the second prism cooperates with the mirrored face of the first prism. When the first and second prisms are turned as a unit, the inclined face of the first prism either passes a light beam arriving from the entrance face through to the second prism and out one of the exit faces or totally reflects the arriving light beam to the mirrored face. The light beam reflected back from the mirrored face now passes through the inclined face to the second prism and out the cooperating exit face of the second prism.
    Type: Grant
    Filed: September 5, 1985
    Date of Patent: October 6, 1987
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuhisa Sato, Yasuyuki Yamada, Hiroki Nakayama, Kouji Oizumi
  • Patent number: 4652091
    Abstract: A compact zoom lens is constructed with, from front to rear, first, second and third lens units of positive, negative and positive refractive powers, respectively. A diaphragm is positioned in or adjacent the second lens unit. The second lens unit and the diaphragm are stationary. When zooming from the wide angle end to the telephoto end, the first and third lens units are axially moved in such a manner that each of the separations between the first and second lens units and between the second and third lens units is increased monotonically.
    Type: Grant
    Filed: July 3, 1985
    Date of Patent: March 24, 1987
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kouji Oizumi, Yasuhisa Sato, Yasuyuki Yamada, Hiroki Nakayama
  • Patent number: 4643536
    Abstract: A conversion lens upon attachment on the image side of a master lens increases the focal length of the entire system. The conversion lens comprises three components of negative, positive and negative powers in this order from the front, has a negative power as a whole, and satisfies the following conditions:2.0<f1/f3<4.00.8<.vertline.f2/f3.vertline.<1.2n1-n2>0.15where fi and ni are the focal length and the refractive index of the glass of the i-th component counting from the front respectively.
    Type: Grant
    Filed: June 28, 1985
    Date of Patent: February 17, 1987
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuyuki Yamada, Yasuhisa Sato, Hiroki Nakayama, Kouji Oizumi