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US 5,689,738 AGranted
Camera having back focus adjusting apparatus
AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha
InventorsSeiji Uziie, Kazuyoshi Azegami, Hiroshi Nomura
Life of this patent
Estimating the term…
Abstract
A camera having an apparatus for adjusting a back focus by varying a distance between a rearmost point of lens groups of a photographing optical system and focal plane. The apparatus includes a stationary barrel that supports the lens groups and is fixed to the camera body, and a restricting mechanism that is provided between the camera body and the stationary barrel. The restricting mechanism restricts rotational movement of the stationary barrel with respect to the camera body, while allowing movement of the stationary barrel in an optical axis direction with respect to the camera body.
Claims32
A camera having an apparatus for adjusting a back focus, comprising:
- a rotationally stationary barrel that is fixed to an associated camera body;
- a cam ring that is threadedly engaged with said rotationally stationary barrel on an inner peripheral surface of said rotationally stationary barrel;
- a gear train for rotating said cam ring by transmitting a driving force through a circumferential gear that is provided on an outer peripheral surface of said cam ring, wherein a back focus adjustment is effected by moving said rotationally stationary barrel in an optical axial direction;
- a final gear;
- and
- a transmitting gear;
- wherein,
- said final gear and said transmitting gear are components of said gear train, said final gear being engaged with said circumferential gear, and said transmitting gear engaging said final gear, and wherein said final gear and said transmitting gear are supported on said rotationally stationary barrel so that said final gear and said transmitting gear move together with said rotationally stationary barrel in the optical axial direction upon back focus adjustment, the back focus adjustment being effected in accordance with movement of said rotationally stationary barrel in the optical axial direction.
5 more elements
A camera having an apparatus for adjusting a back focus, comprising:
- a rotationally stationary barrel to be secured to a camera body, said rotationally stationary barrel including movable lens groups comprising a photographing lens and including a threaded portion;
- restricting means for preventing rotational movement of said rotationally stationary barrel and for permitting axial movement of said rotationally stationary barrel;
- and
- an adjusting ring provided in said camera body and including a threaded portion directly threadedly engaging with said threaded portion of said rotationally stationary barrel,
- direct engagement of said threaded portion of said rotationally stationary barrel and said threaded portion of said adjusting ring comprising means for adjusting a position of said rotationally stationary barrel in an optical axial direction in accordance with rotation of said adjusting ring.
2 more elements
A camera having an apparatus for adjusting a back focus, comprising:
- a rotationally stationary barrel to be secured to a camera body, said rotationally stationary barrel including movable lens groups comprising a photographing lens;
- means for preventing rotational movement of said rotationally stationary barrel with respect to the camera body;
- adjusting means, engaged with said rotationally stationary barrel, for transmitting movement to said rotationally stationary barrel;
- means mounting said adjusting means to prevent axial movement of said adjusting means and to permit rotational movement of said adjusting means;
- means for selectively preventing and permitting rotational motion of said adjusting means;
- and
- means for coupling said adjusting means and said rotationally stationary barrel to move said rotationally stationary barrel along an optical axial direction in association with rotational movement of said adjusting means to thereby adjust a back focus of the photographing lens.
4 more elements
A camera having a back focus adjusting apparatus, comprising:
- a rotationally stationary barrel to be secured to a camera body;
- a cam ring threadedly engaged with said rotationally stationary barrel on an inner peripheral surface of said rotationally stationary barrel and;
- a gear train for rotating said cam ring by transmitting a driving force to a circumferential gear positioned on an outer peripheral surface of said cam ring, said gear train including a final gear engaged with said circumferential gear of said cam ring, said final gear being supported on said rotationally stationary barrel so as to move together with said rotationally stationary barrel in an optical axial direction during a back focus adjustment operation, said back focus adjustment operation defined by movement of said rotationally stationary barrel in the optical axial direction.
A camera having an apparatus for adjusting a back focus, comprising:
- a rotationally stationary barrel to be secured to a camera body, said rotationally stationary barrel including moveable lens groups comprising a photographing lens;
- guide means for guiding said rotationally stationary barrel for movement in an optical axial direction while restricting rotational movement of said rotationally stationary barrel with respect to said camera body;
- an adjusting ring provided in said camera body and being threadedly engaged with an outer periphery of said rotationally stationary barrel, said adjusting ring being rotatable with respect to the optical axial direction but being restricted from movement in the optical axial direction;
- and
- adjusting means for adjusting a position of said rotationally stationary barrel in the optical axial direction in association with rotation of said adjusting ring with respect to said camera body.
2 more elements
A camera having an apparatus for adjusting a back focus, comprising:
- a rotationally stationary barrel to be secured to a camera body, said rotationally stationary barrel including movable lens groups comprising a photographing lens and including a threaded portion;
- a restricting mechanism that prevents rotational movement of said rotationally stationary barrel and permits axial movement of said rotationally stationary barrel;
- and
- an adjusting ring provided in said camera body and including a threaded portion directly threadedly engaging with said threaded portion of said rotationally stationary barrel,
- direct engagement of said threaded portion of said rotationally stationary barrel and said threaded portion of said adjusting ring comprising a mechanism that adjusts a back focus by adjusting a position of said rotationally stationary barrel in an optical axial direction in accordance with rotation of said adjusting ring.
2 more elements
A camera having an apparatus for adjusting a back focus, comprising:
- a rotationally stationary barrel to be secured to a camera body, said rotationally stationary barrel including movable lens groups comprising a photographing lens;
- a mechanism that prevents rotational movement of said rotationally stationary barrel with respect to the camera body;
- an adjuster that is engaged with said rotationally stationary barrel and that transmits movement to said rotationally stationary barrel;
- a structure mounting said adjuster to prevent axial movement of said adjuster and to permit rotational movement of said adjuster;
- a mechanism that selectively prevents and permits rotational motion of said adjuster;
- and
- a coupler that couples said adjuster and said rotationally stationary barrel to move said rotationally stationary barrel along an optical axial direction in association with rotational movement of said adjuster to thereby adjust a back focus of the photographing lens.
4 more elements
A camera having an apparatus for adjusting a back focus, comprising:
- a rotationally stationary barrel to be secured to a camera body, said rotationally stationary barrel including moveable lens groups comprising a photographing lens;
- a guide structure that guides said rotationally stationary barrel for movement in an optical axial direction while restricting rotational movement of said rotationally stationary barrel with respect to said camera body;
- an adjusting ring provided in said camera body and being threadedly engaged with an outer periphery of said rotationally stationary barrel, said adjusting ring being rotatable with respect to the optical axial direction but being restricted from movement in the optical axial direction;
- and
- an adjuster that adjusts a position of said rotationally stationary barrel in the optical axial direction in association with rotation of said adjusting ring with respect to said camera body.
2 more elements
Dependencies are inferred from the claim text.