Fuji Photo Optical Co., Ltd.

Masaya Nozawa

Yukio Noguchi

Syunji Nishimura

Haruo Onozuka

Fumio Iwai

Noboru Shimada

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.

Zoom lens device

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.

Lens driving apparatus

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.

Lens barrel

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. In a range where the first and second helicoid threads do not threadably engage with each other, the groove has a nonparallel region not parallel to at least the first helicoid thread.

Moving mechanism

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.

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.

Growing community of inventors

Saitama, Japan

Masaya Nozawa