Abstract: The present invention provides a lens barrel in which all lens groups are attached to a leading cylindrical body. A movable lens group of the lens groups is moved by a driving source incorporated in the leading cylindrical body. The lens barrel is less likely to be influenced by external forces and can be made smaller. The lens barrel includes first, second, and third cylinders, and first, second, and third lens groups attached to the third cylinder, which is extended first among the first, second, and third cylinders. The first and third lens groups are fixed to the third cylinder, and the second lens group is disposed between the first and third lens groups and movable along the optical axis.

Abstract: A zoom lens device includes a zoom optical system, in which front, middle and rear lens groups are set at one focal length between a wide-angle end where a focal length is short and a telephoto end where the focal length is long. Lens barrels move in first and second regions to move the front, middle and rear lens groups along an optical axis. The lens barrels, when in the first region, focus the zoom optical system with a predetermined focal length kept by maintaining an interval between the front and middle lens groups, and when in the second region, change the focal length of the zoom optical system. A combination of a cam follower pin and a cam groove effects focusing by moving the middle lens group relative to the front lens group along the optical axis when the lens barrels are in the second region.

Abstract: The present invention provides a lens driving apparatus which can prevent a lens barrel from increasing its size and cost while making it possible to detect the position of a movable lens group. A first lens group, a second lens group, and a third lens group are disposed along an optical axis, among which the second lens group is a movable lens group movable along the optical axis. A second lens frame holding the second lens group is formed with a detection plate having a predetermined width in the direction of optical axis. A detector detects passages of both end portions of the detection plate, whereby the position of the second lens group can be detected.

Abstract: The present invention provides a lens barrel which can carry out barrier opening/closing operations and lens moving operations of an optical lens system by use of a single driving source, and can adjust the focus without any obstruction even in a state allowing the baffler to open/close. A state capable of transmitting a driving force to a barrier opening/closing mechanism is attained when collapsing a lens barrel to a predetermined extent or more, and a state incapable of transmitting the driving force to the barrier opening/closing mechanism is attained when the lens barrel is extended to a predetermined extent or more, whereby a single motor can carry out baffler opening/closing operations and lens moving operations of a lens is optical system.

Abstract: A zoom lens device includes a zoom optical system, in which front, middle and rear lens groups are set at one focal length between a wide-angle end where a focal length is short and a telephoto end where the focal length is long. Lens barrels move in first and second regions to move the front, middle and rear lens groups along an optical axis. The lens barrels, when in the first region, focus the zoom optical system with a predetermined focal length kept by maintaining an interval between the front and middle lens groups, and when in the second region, change the focal length of the zoom optical system. A combination of a cam follower pin and a cam groove effects focusing by moving the middle lens group relative to the front lens group along the optical axis when the lens barrels are in the second region.

Abstract: A moving mechanism for a cylinder is provided, in which a projection and groove are engaged by relative movement different from that of a helicoid mechanism and movement of inner and outer cylinders relative to each other can be freely set. In the moving mechanism, a first helicoid thread is helically formed on the inner surface of an intermediate cylinder, a second helicoid thread that threadably engages with the first helicoid thread is helically formed on the outer surface of a movable cylinder, and the intermediate cylinder is rotated so the movable cylinder is moved relative to the intermediate cylinder. A projection is formed on the outer surface of the movable cylinder and a groove engageable with the projection is formed in the inner surface of the intermediate cylinder. In a range where the first and second helicoid threads threadably engage with each other upon relative movement of the movable cylinder, the groove is formed parallel to the first helicoid thread.

Abstract: A lens driving apparatus includes an intermediate barrel expandable and collapsible in an optical axis direction, for moving a rear lens group in the optical axis direction along with expanding and collapsing; a movable barrel, concentric with the intermediate barrel, expandable and collapsible with respect to the intermediate barrel along with the expanding and collapsing of the intermediate barrel, for moving a front lens group in the optical axis direction when expanding from the intermediate barrel; and a click ball for holding the front lens group when the movable barrel collapses, so as to move the front lens group together with the intermediate barrel. As a consequence, when the movable barrel collapses, the front lens group can be held and moved together with the intermediate barrel so the focus can be adjusted appropriately, and the apparatus can be made smaller at a lower cost.

Abstract: A barrier opening and closing apparatus for opening and closing a barrier according to a rotation of a lens barrel containing an optical lens system includes a ring member rotatable about an optical axis of the optical lens system and opening and closing the barrier according to rotation of the ring member. The ring member has rotational force transmitting parts extending rearward, parallel to the optical axis and engaging the lens barrel. The ring member is directly rotated by the rotational force transmitting parts engaged with the lens barrel, to open and close the barrier so the cost of the apparatus can be reduced.

Abstract: A moving mechanism for a cylinder is provided, in which a projection and groove are engaged by relative movement different from that of a helicoid mechanism and movement of inner and outer cylinders relative to each other can be freely set. In the moving mechanism, a first helicoid thread is helically formed on the inner surface of an intermediate cylinder, a second helicoid thread that threadably engages with the first helicoid thread is helically formed on the outer surface of a movable cylinder, and the intermediate cylinder is rotated so the movable cylinder is moved relative to the intermediate cylinder. A projection is formed on the outer surface of the movable cylinder and a groove engageable with the projection is formed in the inner surface of the intermediate cylinder. In a range where the first and second helicoid threads threadably engage with each other upon relative movement of the movable cylinder, the groove is formed parallel to the first helicoid thread.

Abstract: The present invention provides a lens barrel which can carry out barrier opening/closing operations and lens moving operations of a lens optical system by use of a single driving source, and can adjust the focus without any obstruction even in a state allowing the barrier to open/close. A state capable of transmitting a driving force to a barrier opening/closing mechanism is attained when collapsing a lens barrel 1 to a predetermined extent or more, and a state incapable of transmitting the driving force to the barrier opening/closing mechanism is attained when the lens barrel 1 is expanded to a predetermined extent or more, whereby a single motor can carry out barrier opening/closing operations and lens moving operations of a lens optical system.

Abstract: The present invention provides a lens barrel in which all of a plurality of lens groups are attached to a leading cylindrical body, whereas a movable lens group in the plurality of lens groups is moved by a driving source incorporated in the leading cylindrical body, whereby the lens barrel is less likely to be influenced by external forces and can be made smaller. The lens barrel comprises first, second, and third cylinders, and first, second, and third lens groups attached to the third cylinder, which is expanded earliest among the first second, and third cylinders. The first and third lens groups are fixed to the third cylinder, whereas the second lens group is disposed between the first and third lens groups so as to be movable along the optical axis.

Abstract: The present invention provides a lens driving apparatus which can prevent a lens barrel from increasing its size and cost while making it possible to detect the position of a movable lens group. A first lens group, a second lens group, and a third lens group are disposed along an optical axis, among which the second lens group is a movable lens group movable along the optical axis. A second lens frame holding the second lens group is formed with a detection plate having a predetermined width in the direction of optical axis. A detector detects passages of both end portions of the detection plate, whereby the position of the second lens group can be detected.

Abstract: A barrier opening and closing apparatus for opening and closing a barrier according to a rotation of a lens barrel containing an optical lens system comprises a ring member disposed rotatable about an optical axis of the optical lens system and adapted to open and close the barrier according to a rotation thereof, whereas the ring member forms a plurality of rotational force transmitting parts extending rearward therefrom in parallel to the optical axis so as to be engaged with the lens barrel. The ring member is directly rotated by way of the plurality of rotational force transmitting parts engaged with the lens barrel, so as to open and close the barrier, whereby the cost of apparatus can be cut down.

Abstract: A variable focal length camera has a lens barrel movable parallel to the optical axis of its taking lens system so as to change over the focal length of the taking lens system at least between a standard photography position and a telephoto position. When the subject distance is nearer than the nearest focusable distance for standard photography or for telephotography, the lens barrel is automatically moved into a first close-up position if the lens barrel has been in the standard photography position, whereas the lens barrel is moved into a second close-up position if the lens barrel has been in the telephoto position.

Abstract: A variable focal length camera having at least one auxiliary lens system which is inserted into or withdrawn from the optical axis of a main lens system. A lens holder holding the auxiliary lens system is swingably mounted on a shaft extending in the direction of the optical axis, and moves forward and rearward along the shaft for focus adjustment. In order to cancel the component of a force in the direction of the optical axis exerted by a tool by which a focus adjusting device is operated, the shaft is arranged to be motionless in the direction of the optical axis. According to a preferred embodiment, on the intermediate portion of the shaft, there is formed a thread meshing with a base portion of the lens holder so that the position of the lens holder is adjusted through rotation of the shaft, and after this lens position adjustment the base portion is fixed to the shaft.

Abstract: A zoom lens system shifts the position of front and rear lens groups relative to each other in the direction of the optical axis to change its focal length, by moving a lens barrel back and forth in the axial direction. The lens barrel is formed with cutouts in its rear portion for receiving therein parts and elements projecting forwardly from the plane in which an exposure aperture is located when the lens barrel is retracted, so as to reduce the thickness of the camera with the retracted zoom lens. A focal length changing mechanism comprises a fixed cam and a lever attached to the lens barrel which is turned by the cam when the lens barrel moves back and forth to shift one lens group, thereby changing the focal length of the zoom lens to desired focal lengths. To correct the changes in focus of the zoom lens caused by the change of focal length, an adjusting member is provided in the focal length changing mechanism.