Abstract: A step-zoom lens includes two movable lens groups; a lens group support unit; and a cam ring having a cam groove. The cam groove includes a finite number of focal-length steps, so as to perform a focusing operation between infinite and closest photographing positions at each focal-length step. The cam groove includes a wide-angle mode section, a telephoto mode section, and a mode switching section. The closest photographing positions in two adjacent focal-length steps and the infinite photographing positions in two adjacent focal-length steps are adjacent to each other, respectively. One focal-length step of the infinite photographing position at a longest focal length in the wide-angle mode section is provided at one end of the mode switching section, and another focal-length step of the infinite photographing position at a shortest focal length in the telephoto mode section is provided at the other end.

Abstract: A lens distance-varying mechanism for varying a distance between first and second lens groups includes a first lens frame; a second lens frame rotatable relative to the first lens frame; a relative-moving mechanism for moving the first and second lens frames to change a relative position therebetween on an optical axis when the second lens frame is positioned at each of forward and reverse rotation extremities thereof relative to the first lens frame; a differential linking ring which rotates together with the second lens frame; a differential ring which is rotated relative to the differential linking ring by a first angle of rotation greater than a second angle of rotation of the second lens frame relative to the first lens frame; and a biasing member, positioned between the differential ring and the differential linking ring, for absorbing a difference between the first and second angles of rotation.

Abstract: A lens barrel includes cam ring which is rotated about an optical axis to move a lens group in the optical axis direction, and a rotational ring which transfers a rotational motion to the cam ring. The rotational ring includes a rotation-transmission arm extending in the optical axis direction. The cam ring includes a bottomed engaging recess which is formed on an outer peripheral surface of the cam ring. The rotation-transmission arm is slidably inserted to be movable in the optical axis direction. The rotation-transmission arm and the engaging recess include a guide groove which extends parallel to the optical axis and a guide projection which is engaged in the guide groove, respectively or vice versa, the rotational ring transferring rotational motion thereof to the cam ring via engagement of the guide groove with the guide projection.

Abstract: A lens assembly includes an exposure control unit having an exposure control member; a lens drive unit including a lens drive mechanism which moves a photographing lens group in an optical axis direction; center apertures which are formed in the exposure control unit and the lens drive unit, respectively, at the center portions thereof, which define a lens movement opening when the exposure control unit and the lens drive unit are connected to each other; and a lens support frame which supports the photographing lens group, the lens support frame being provided in the lens movement openings so as to move in the optical axis direction and driven via the lens drive mechanism.

Abstract: A lens barrel includes a ring member having a cam groove formed on an inner peripheral surface thereof; a lens support ring positioned in the ring member and supported thereby to be rotatable with respect to the ring member, the lens support ring having a first cam follower which is engaged in the cam groove of the ring member; a biasing ring coupled to the lens support ring to be movable in an optical axis direction and to be non-rotatable with respect to the lens support ring, the biasing ring having a second cam follower which is engaged in the cam groove of the ring member; and a biasing device for biasing the lens support ring and the biasing ring in opposite directions to press the first and second cam followers against opposite guide surfaces of the cam groove.

Abstract: A stopper structure for use in a lens barrel assembly, the lens barrel assembly having a helicoid ring which includes a male helicoid, on the outer periphery of the helicoid ring, for engaging with a female helicoid on an inner periphery of a fixed barrel secured to a camera body; and gear teeth formed along the male helicoids to extend between the male helicoids and arranged in a circumferential direction about an optical axis, the helicoid ring moving along the optical axis while been driven by a pinion which is engaged with the gear teeth; wherein the stopper structure includes a stopper member which engages with at least one tooth of the gear teeth in order to prevent rotation of the helicoid ring.

Abstract: A lens barrel having a zoom lens system including a plurality of variable power lens groups which includes a switching lens group having two sub-lens groups which are optically operable in mutually close and distant positions, the lens barrel includes a first sub-lens group frame for supporting one sub-lens group; a second sub-lens group frame for supporting the other sub-lens group; a switching lens group frame for supporting the first and second sub-lens group frames; a shift mechanism for selectively moving the first and second sub-lens group frames in the switching lens group frame to the mutually close and distant positions; and a switching lens group frame moving mechanism for moving the switching lens group frame with the other variable power lens group(s) along a predetermined path to vary the focal length; wherein combined movement of the shift mechanism and the switching lens group frame moving mechanism provides a zoom path for the sub-lens groups.

Abstract: A lens guide mechanism includes a lens frame which supports a photographing lens group, the lens frame including a plurality of guide holes extending in a direction parallel with an optical axis; a support barrel in which the lens frame is provided; a gear holding member which is provided at a front end of the support barrel; a gear train which is held between the support barrel and the gear holding member, the gear train constituting a drive mechanism for the lens frame; and a plurality of linear movement guide rods provided in the gear holding member, which extend through the guide holes of the lens frame and support the lens frame to move linearly in the optical axis direction relative to the support barrel.

Abstract: A lens barrel includes front and rear lens group frames, and a cam ring having a cam groove including a front-lens-group accommodation portion, a rear-lens-group-accommodation portion having a straight connecting portion connected to the front-lens-group accommodation portion, and an end portion. The front lens group frame is linearly guided and the rear lens group frame is relatively rotatably supportable and linearly guidably supportable. Rotation of the rear lens group frame is allowed when first and second followers are positioned in the front and rear-lens-group accommodation portions. When the cam ring is rotated from the accommodation portions, upon the rear lens group frame being switched from the relatively rotatable state to the linearly guidable state, the second follower rotates together with the cam ring while the second follower is positioned in the rear-lens-group accommodation portion or in the vicinity of the straight connecting portion.

Abstract: A lens shutter mechanism includes, between front and rear support frames having photographing apertures, shutter sectors which open and close the photographing apertures; a shutter drive ring which is rotatable about the optical axis to drive the shutter sectors; diaphragm sectors which change an aperture diameter of the photographing apertures independently of the shutter sectors; and a diaphragm drive ring which is rotatable about the optical axis to drive the diaphragm sectors. The shutter drive ring and the diaphragm drive ring are located at different radial positions and at the same optical axis position. One and the other of the shutter drive ring and the diaphragm drive ring is provided with an inner flange and an outer flange respectively, which radically project toward each other so as to overlap in the axial direction, and engage so as to be relatively slidable in the circumferential direction.

Abstract: A zoom lens mechanism includes a switching lens group frame which supports a first sub-lens group frame and a second sub-lens group frame; a shift cam mechanism provided on opposed surfaces of the first and second sub-lens group frames, respectively, the shift cam mechanism causing the first and second sub-lens group frames to move to a mutually close position or mutually distant position; an actuator ring for providing relative rotation between the first and second sub-lens group frames; a receiving surface provided on the switching lens group frame wherein a rear end surface of the actuator ring abuts against the receiving surface; and a biasing device for biasing the first sub-lens group frame toward the actuator ring to force the first and second sub-lens group frames, and the actuator ring against the receiving surface, so that the shift cam mechanism come into contact with each other.

Abstract: An FPC mounting structure for a lens shutter having a lens-shutter unit having therein a photographing lens and a shutter, and an FPC which is adapted to connect the lens-shutter unit to a control circuit, includes a circumferentially extending FPC which is supported along an outer surface of the lens-shutter unit, and an axially extending FPC which extends in the optical axis direction and which is connected to the control circuit. The circumferentially extending FPC and the axially extending FPC are constructed separately and are connected to each other in a press-contact state.

Abstract: A zoom lens mechanism includes a switching lens group frame supporting a first sub-lens group frame and a second sub-lens group frame which support first and second sub-sub-lens groups, respectively; a lens group shift mechanism for causing the first and second sub-lens group frames to linearly move to a mutually close position or a mutually distant position, with respect to the optical axis direction, in accordance with relative rotation between the first sub-lens group frame and the second sub-lens group frame; and a focusing mechanism which integrally moves the first sub-lens group frame and the second sub-lens group frame in the optical axis direction while maintaining a distance therebetween after the first and the second sub-lens group frames are moved to one of the mutually close position and the mutually distant position by the lens group shift mechanism.

Abstract: A shift mechanism includes first and second ring bodies which are relatively rotatable; a shift cam surface formed on the first ring body on an end surface thereof which faces the second ring body, the shift cam surface being inclined with respect to a circumferential direction of the first ring body; a follower projection formed on the second ring body for engaging with the shift cam surface; and a rotating mechanism for relatively rotating the first and second ring bodies. The shift cam surface and the follower projection are arranged to move the first and second ring bodies toward and away from each other in the axial direction as the first and second ring bodies are relatively rotated. An annular rib is formed along the circumference of the first ring body outside the shift cam surface over the follower projection of the second ring body.

Abstract: A lens barrel includes an optical system having front and rear lens groups; a front lens frame which supports the front lens group; a rear lens frame which supports the rear lens group; a lens frame drive mechanism for driving the front and rear lens frames, and allows the rear lens frame to rotate relative to the front lens frame or move together in the optical axis direction while preventing relative rotation therebetween; a shutter unit having a shutter and a flexible printed wiring board, the shutter unit being relatively rotatable to, and movable together with, the rear lens frame in the optical axis direction; and a shutter unit guide mechanism for linearly guiding the shutter unit in the optical axis direction without rotating the shutter unit regardless of whether the rear lens frame rotates relative to the front lens frame.

Abstract: A lens barrel having a zoom lens system including variable power lens groups, at least one of which includes a switching lens group having two sub-lens groups, the lens barrel includes a first sub-lens group frame for supporting one of the sub-lens groups; a second sub-lens group frame for supporting the other sub-lens group; a switching lens group frame for supporting the first and second sub-lens group frames; a lens shutter mechanism secured to the switching lens group frame on the image side of the second sub-lens group frame; and a focusing mechanism for making the second sub-lens group frame advance or retreat, with respect to a reference position provided by the lens shutter mechanism secured to the switching lens group frame. The first and second sub-lens group frames are integrally moved along in the optical axis direction via the focusing mechanism.

Abstract: An engagement structure for cylindrical members includes a first cylindrical member including a plurality of engagement projection portions of different shapes having the same projecting length in the radial direction, and a second cylindrical member including a plurality of groove portions corresponding to the engagement projection portions, each the groove portions having at least one groove, wherein one of the first and second cylindrical members is accommodated inside the other of the first and second cylindrical members. The engagement projection portions and the corresponding groove portions can be engaged and disengaged only at one relative circumferential position of the first and second cylindrical members, and at a relative circumferential position other than the one relative circumferential position, the engagement projection portions of the first cylindrical member are always engaged with at least a portion of the groove portions other than the grooves thereof.

Abstract: A retractable lens system includes a plurality of optical elements. All of the plurality of optical elements are positioned on a common optical axis when the retractable lens is in use. A removable element of the plurality of optical elements is moved to a removed position outside of the common optical axis, and the removable element and at least one element of the remaining elements of the plurality of optical elements are moved rearward, respectively, when the retractable lens system is in a retracted position.

Abstract: A lens barrel includes a cam ring which is rotated about an optical axis to move a lens group in the optical axis direction via a cam groove formed on the cam ring, and a rotational ring which transfers a rotational motion to the cam ring. The rotational ring includes a rotation-transmission arm extending in the optical axis direction. The cam ring includes an engaging recess formed on an outer peripheral surface of the cam ring, and in which the rotation-transmission arm is slidably inserted to be movable in the optical axis direction, and an outer flange formed on an outer peripheral surface of the cam ring to form a slot penetrating therethrough in the optical axis direction between the outer flange and a bottom radial surface of the engaging recess so that the rotation-transmission arm is slidably fitted in the engaging recess through the slot.

Abstract: A lens barrel includes front and rear lens group frames, and a cam ring having a cam groove including a front-lens-group accommodation portion, a rear-lens-group-accommodation portion having a straight connecting portion connected to the front-lens-group accommodation portion, and an end portion. The front lens group frame is linearly guided and the rear lens group frame is relatively rotatably supportable and linearly guidably supportable. Rotation of the rear lens group frame is allowed when first and second followers are positioned in the front and rear-lens-group accommodation portions. When the cam ring is rotated from the accommodation portions, upon the rear lens group frame being switched from the relatively rotatable state to the linearly guidable state, the second follower rotates together with the cam ring while the second follower is positioned in the rear-lens-group accommodation portion or in the vicinity of the straight connecting portion.