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US 4,538,062 AGranted
Focusing detecting device with coaxial source and detector
AssigneeOlympus Optical Co., Ltd.
InventorYoshio Shishido
Life of this patent
Estimating the term…
Abstract
The focusing detecting device determines whether or not the optical image of an object to be photographed is in a focusing state in which the image is clearly formed on a predetermined image forming surface through a photographing or image forming optical system. The device can be used with a dark optical system.
Claims31
A focusing detecting device comprising
- an optical system defining an optical axis between an image forming surface and an object to be photographed;
- a light projecting means having a small aperture for projecting a light therethrough and along said optical axis onto the object to be photographed;
- and
- a light receiving means having a small aperture for receiving light reflected from the object along said axis and a photoelectric converting surface adjacent said aperture with at least one of said aperture and said surface being in a position optically conjugate with the image forming surface said surface being disposed to emit a signal in response to the reflected light being received thereon whereby a focused state is detected with the reflected light being received within said aperture of said light receiving means.
1 more element
A focusing detecting device for an image forming surface comprising
- an optical system defining an optical axis between the image forming surface and an object;
- a light source for projecting a light along said axis to the object;
- and
- a photoelectric element having at least one small aperture between said light source and said optical axis for projecting a spot of the light from said source onto the object and for receiving light reflected from the object along said axis and a photoelectric converting surface at a position optically conjugate with the image forming surface and about said aperture.
1 more element
In combination,
- a focusing detecting device for an image forming surface, said detecting device including an optical system having at least one movable lens in an optical axis between the image forming surface and an object, a light projecting means for projecting a light through a small aperture and along said axis to the object and a light receiving means having at least one small aperture for receiving light reflected from the object along said axis and a photoelectric converting surface near a position optically conjugate with the image forming surface for emitting an electric signal ouput in response to light thereon;
- and
- a focusing setting device including a driving means for moving said lens of said optical system in response to said electric signal output to focus an image of the object on the image forming surface.
A focusing detecting device comprising
- an optical system defining an optical axis between an image forming surface and an object to be photographed;
- a light projecting means having at least two small apertures for projecting light therethrough and along said optical axis onto the object to be photographed;
- and
- a light receiving means having at least a pair of small apertures for receiving light reflected from the object along said axis and a photoelectric converting surface adjacent said apertures, at least one of said surface and said pair of apertures being in a position optically conjugate with the image forming surface, said surface being disposed to emit a signal in response to the reflected light being received thereon whereby a focused state is detected with the reflected light being received within said aperture of said light receiving means.
1 more element
A focusing detecting device comprising
- an optical system defining an optical axis between an image forming surface and an object to be photographed;
- at least one pair of light projecting means, each means having a small aperture for projecting light therethrough and along said optical axis onto the object to be photographed;
- and
- at least one pair of light receiving means disposed on opposite sides of a plane optically conjugate with said image forming surface, each light receiving means having a small aperture for receiving light reflected from the object along the axis and a photoelectric converting surface adjacent said aperture for emitting a signal in response to the reflected light being received thereon whereby a focused state is detected by equal signals emitted from said surfaces.
1 more element
A focusing detecting device comprising
- an optical system defining an optical axis between the image forming surface and an object;
- a light source for projecting a light along said axis to the object;
- a first plate having an aperture between said light source and said axis for passing a spot of light from said source;
- a photoelectric element for receiving light reflected from the object along said axis for emitting a signal in response to the amount of light received thereon;
- and
- a second plate having an aperture between said axis and said element at a position optically conjugate with the image forming surface whereby a focused state is detected with said element emitting a signal of maximum output level.
3 more elements
Dependencies are inferred from the claim text.