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US 6,603,609 B2Granted
Zoom lens barrel having variable fully-open aperture value function
AssigneeCanon Kabushiki Kaisha
InventorRyuichi Nagae
Life of this patent
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AssigneeCanon Kabushiki Kaisha
InventorRyuichi Nagae
Estimating the term…
A lens barrel includes a variable power lens unit, an aperture-variable light-amount adjusting unit having an adjusting member that adjusts the fully open state of the aperture, and a variable power lens control mechanism that shifts the variable power lens unit from a first variable power position to a second variable power position. The variable power lens control mechanism moves the variable power lens unit beyond the second variable power position, then returns it toward the second variable power position, and stops it at the second variable power position. The lens barrel further comprises a cam member having a cam portion with which the adjusting member is engaged, and moves relative to the light-amount adjusting unit in operative association with the control action of the variable power lens control mechanism.
A lens barrel, comprising:
A camera comprising:
Dependencies are inferred from the claim text.
From the US filing history. Foreign family members aren’t listed.
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By relative axial movement of several lenses, e.g. of varifocal objective lens: controlled by a microcomputer
Optical elements, systems or apparatus
Term ended 7 Mar 2022 (estimated)
1. Field of the Invention
The present invention relates to a lens barrel or a camera having a shutter which is used for the exposure control of the camera, and which particularly constitutes a mechanism for changing the fully-open aperture value according to a change in the focal length.
2. Description of the Related Art
FIG. 1 is an operational diagram of a lens barrel and cam in a camera according to an embodiment of the present invention;
FIGS. 2A and 2B are views showing the lens barrel provided in the camera according to the embodiment of the present invention, wherein FIG. 2A is a perspective view thereof and FIG. 2B is a sectional view thereof;
FIG. 3 is a partial sectional view showing the shutter mechanism 13 of the camera according to the embodiment of the present invention;
FIGS. 2A and 2B are views showing a lens barrel provided in a camera according to an embodiment of the present invention, wherein FIG. 2A is a perspective view thereof and FIG. 2B is a sectional view thereof.
Referring to FIGS. 2A and 2B, reference numeral 1 denotes a fixed tube fixed to the camera body (not shown). This fixed tube 1 has a helicoid screw formed on the inner peripheral surface thereof. Reference numeral 2 denotes a lightproof rubber seal affixed at the front end of the fixed tube 1 for preventing external light from entering the lens barrel.
Reference numeral 3 denotes a first differential tube, which is rotated about the optical axis by the driving force of a motor (not shown). A helicoid screw is formed on the outer peripheral surface at the rear end portion of the first differential tube 3, and this helicoid screw is engaged with the helicoid screw formed on the fixed tube 1. Thereby, when the first differential tube 3 undergoes the driving force of the motor, the first differential tube 3 moves back and forth in the optical axis direction while rotating about the optical axis in helicoidal engagement with the fixed tube 1. Reference numeral denotes a lightproof rubber seal affixed at the front end of the first differential tube 3.