Abstract: Provided is a lens apparatus having a first holding member that holds a first lens unit and a second holding member that holds the first holding member, in which the first and second holding members are engaged with each other so as to be capable of relative movement by means of a plurality of engagement portions provided circumferentially at unequal intervals including a first interval and a second interval larger than the first interval, and in which there is provided, in a portion between the engagement portions arranged at the second interval in at least one of the first and second holding members, an abutment portion radially abutting the other holding member.

Abstract: A zoom lens barrel comprises an exterior unit, which mainly forms an exterior portion, an optical unit having an image pickup optical system built therein, and a control unit and can be detachably mounted on a single-lens reflex camera. The optical unit includes first and second group lenses as the image pickup optical system, which can move forward and rearward in zooming and focusing, and a third group lens which can move forward and rearward in zooming. Particularly, in focusing, a first group lens holding frame for holding the first group lens and a second group lens holding frame for holding the second group lens are driven forward and rearward in a different amount in an optical axis direction through a cam follower and two cam grooves by driving a focus ring in rotation, thereby focusing is executed. The lens barrel can cope with a forward/rearward movement required in zooming and focusing and can be reduced in size.

Abstract: A cam mechanism includes a cam ring, and a linearly movable frame movable supporting an optical element. The cam grooves are located at different positions in the optical axis direction and which trace a same reference cam diagram. All cam grooves are partial cam grooves each having at least one end opening at at least one of opposite ends of the cam ring, so as not to include an entire portion of the reference cam diagram. Cam followers are located at different positions at least in the optical axis direction and are respectively engageable in the cam grooves. At least one of the cam followers remains engaged in a corresponding cam groove while at least one of the other of the cam followers comes out of the end opening and is disengaged therefrom when the linearly movable frame moves to movement limit in the optical-axis direction.

Abstract: A lens barrel extending and retracting mechanism. A photographic optical axis and a central axis of a lens barrel are eccentric such that a first lens group and a second lens group are housed in a side of a CCD separated from the optical axis. The lens barrel is rotatably extended around the central axis thereof, and a picture is taken when lens optical axes of the first lens group and the second lens group coincide with the optical axis. The lens barrel extending and retracting mechanism prevents displacement and tilt of the lens optical axes of the first lens group and the second lens group, maintaining optical performance and reducing the size of the lens barrel in the housed position.

Abstract: A selection device which permits or prohibits serial communication is provided in a lens apparatus capable of performing serial communication to suppress the serial communication although a camera body can perform the serial communication. Thus, a safe operation of the system can be guaranteed. At the same time, the processing speed of the processing circuit in the lens apparatus can be reduced, thereby successfully reducing the power consumption.

Abstract: A lens barrel includes a rotatable ring, a non-rotatable outer annular member having a circumferential groove located on the inner peripheral surface thereof, an advancing/retracting mechanism configured to move the rotatable ring along the optical axis between movement limits of the rotatable ring, a rotational projection located on the outer peripheral surface of the rotatable ring such that the projection is engaged in the circumferential groove when the rotatable ring is moved to one of the movement limits, and a stopper which is insertable into and removable from the circumferential groove at an intermediate point between opposite ends of the groove.

Abstract: A lens barrel is retractable in electronic equipment having an image-generating device, such as a CCD. During photographing, the lens barrel relocates a first lens group and a second lens group to a predetermined position in an optical axis to zoom the image of an object. During collapsing, the first lens group and the second lens group adjacent to the object side are transferred to a side of a CCD which is away from the optical axis and a focus driving mechanism drives the third lens group along the optical axis. The focus driving mechanism is disposed inside the lens barrel.

Abstract: A lens barrel has its length which is reduced by dispensing with guide rods or a travel mechanism long extending from a base which fixes an image pickup device. The optical axes of multiple lens groups can be easily aligned. An image taking apparatus has its body which has the lens barrel incorporated into it. A second lens group, third lens group and, via the travel mechanism, a fourth lens group are supported by a straight-ahead key ring, and the straight-ahead key ring also supports a front tube holding the first lens group. A zoom motor and a focus motor are also supported by the straight-ahead key ring.

Abstract: To the female helicoidal screw of the lens barrel (outer barrel body), there is always imparted a biasing force from a plurality of looseness eliminating springs formed on the outside peripheral portion of the lens barrel (inner barrel body) which are integrally supported on the lens barrel (inner barrel body), by means of the male helicoidal screw, and the male helicoidal screw is slid while being thrusted against the female helicoidal screw.

Abstract: A rotation transfer mechanism of a lens barrel includes a pair of rotatable rings, adjacent ends of which are opposed to each other; an axial-direction projection extending in the rotational axis direction; an axial-direction recess in which the axial-direction projection is positioned; a rotation transfer groove located on an inner peripheral surface of the one of the rotatable rings that has the axial-direction projection, wherein a circumferential position of the rotation transfer groove corresponds to a circumferential position of the axial-direction projection; a driven rotational member having a rotation transfer protrusion engaged in the rotation transfer groove, the rotation transfer protrusion slidably movable in the rotation transfer groove in the rotational axis direction and configured to transmit rotation of the rotatable ring to the driven rotational member; and at least one optical element configured to be driven by the driven rotational member.

Abstract: In manufacturing an optical device having a plurality of optical modulators and a color combining optical system, optical properties of a projection optical system are acquired, reference positions of the optical modulators are acquired, deviations of the optical modulators are calculated based on previously acquired optical properties, and the positions of the optical modulators are adjusted based on the deviations while detecting a combined light from the color combining optical system.

Abstract: An adjustment mechanism for adjusting an axial position of one lens component relative to other lens components of an optical lens system comprises a lens holding frame mounting the lens component that has a peripheral locating seat and a cylinder holding and allowing the lens holding frame to rotate about and move along the optical axis that has an axial position selective collar with a flight of stairs. The lens holding frame is rotated to bring the locating seat into abutment selectively against the stairs, so as thereby to position the lens component mounted in the lens holding frame at a desired axial n with respect to the remaining lens components.

Abstract: A lens barrel includes a lens-holding cylinder which supports a lens and is provided with a cam-follower and a rectilinear key; a cam-cylinder having a cam-groove which engages with the cam-follower so as to apply a driving force to the lens-holding cylinder in the optical-axis direction; and a guide cylinder which is enclosed by the cam-cylinder and has a rectilinear guide opening that engages with the rectilinear key so as to guide the lens-holding cylinder in the optical-axis direction. A segment of the cam-cylinder adjacent to an object to be photographed has a greater wall thickness such that the cam-cylinder has a level difference. A portion of the guide cylinder adjacent to an object to be photographed, which corresponds to the level difference of the cam-cylinder, is made thinner by the amount of the level difference.

Abstract: A guide mechanism for a lens barrel includes a support frame supporting an imaging component, and a linear guide configured to guide the support frame along an axis. The linear guide can include a ring portion defining an opening through which the support frame can pass, and further includes at least one linear guide key extending along the axis from the ring portion and positioned substantially radially inwardly of the opening. The support frame has at least one linear guide groove located at the outer peripheral surface thereof and configured to slidably engage with a respective the at least one linear guide key, and each of the opposite ends of the at least one linear guide groove are open such that the support frame is movable to extend from either of the sides of the ring portion.

Abstract: Even if a stop position during focus adjustment becomes irregular, it is made possible to focus on an object, and also a circuit construction for the focus adjustment can be simplified to thereby make the cost low. For this purpose, the lens device has a zoom lens comprising a plurality of lens units, and a lens driving member for operating the plurality of lens units for the adjustment of zoom and focus, and the lens driving member has at least first areas 20a, 20c continuing to focus on a first object distance and second areas 20b, 20d continuing to focus on a second object distance on a shorter distance side than the first object distance, within a predetermined range in the operating process of the plurality of lens units for the zoom adjustment.

Abstract: A lens barrel includes a holder holding an image pick-up device; a stationary barrel having a female helicoid; a gear/helicoid ring including an annular rib, a male helicoid formed on the annular rib and engaged with the female helicoid, and a spur gear formed on the male helicoid; a pinion engaged with the spur gear; a linear guide ring provided around the gear/helicoid ring; a outer circumferential groove formed on the gear/helicoid ring; and bayonet lugs projecting rearwards from the linear guide ring and engaging in the circumferential groove. Rotation of the gear/helicoid ring causes a lens group to move along the optical axis. At least a portion of a rear end of the male helicoid extends rearwards. At least a portion of the rear extension portion overlaps the holder in the optical axis direction when the gear/helicoid ring stops retracting at a predetermined position.

Abstract: Sliders of a movable lens holder are provided with cam followers respectively. Each of the sliders engages with a guide opening formed in a lens frame so that the movable lens holder is allowed to move in an optical-axis direction. The movable lens holder is retained in a cam barrel provided with cam grooves, which are formed so as to shift their positions in the optical-axis direction and in a rotational direction of the cam barrel. The cam followers engage with the cam grooves respectively.

Abstract: A zoom lens barrel structure includes a first lens frame including an outer ring portion, an inner ring portion, a flange wall, and a first cam follower; a cam ring positioned between the outer and inner ring portions; a second lens frame having a second cam follower, positioned inside the inner ring portion; a first cam groove formed on an outer peripheral surface of the cam ring, the first cam follower being engaged in the first cam groove; a second cam groove formed on an inner peripheral surface of the cam ring so that the second cam follower engages in the second cam groove; a linear guide ring, positioned around the first lens frame; and a linear guide mechanism, provided between the inner ring portion of the first lens frame and the second lens frame, for guiding the second lens frame linearly along the optical axis.

Abstract: A zoom lens barrel includes a linear guide ring; a moving frame having a male helicoid; a rotatable ring coupled to the linear guide ring; a female helicoid formed on the rotatable ring, and engaged with the male helicoid; a switching ring coupled to the rotatable ring; a switching member; and a switching-member moving groove including a first inclined section, a switching section, a second inclined section and an assembling section. The lead angle of the first inclined section is the same but has an opposite inclination to that of the female helicoid. The follower projection is inserted in the first inclined section. The switching section extends parallel to the optical axis. The second inclined section extends parallel to the first inclined section. The assembling section extends rearwards from a front end of the second inclined section to be parallel to the optical axis.

Abstract: A cam mechanism of a lens barrel includes first and second ring members; cam grooves having similar cam diagrams formed on one of the first and second ring members, and cam followers formed on the other thereof. Two groove/follower groups positioned at different positions in a circumferential direction. The cam grooves of one of the two groove/follower groups intersect cam grooves of another of the two groove/follower groups, respectively. One of the following is satisfied: (a) a distance in the optical-axis direction between front and rear groove/follower sets of one of the two groove/follower groups is different from that between the front and rear groove/follower sets of another of the two groove/follower groups, and (b) a distance in the circumferential direction between two front groove/follower sets of the two groove/follower groups is different from that between two the rear groove/follower sets of the two groove/follower groups.

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 cam mechanism for a lens barrel includes an annular member which is linearly guided along an optical axis, and having a cam follower on an outer peripheral surface; a cam ring having a cam groove on an inner peripheral surface including a photographing section and an accommodation section, the cam follower being engaged in the cam groove; and a biasing device for biasing the annular member forward to normally press the cam follower against a front cam surface in the cam groove. A rear end portion of the cam groove is open at a rear end surface of the cam ring to serve as the accommodation section, and the cam follower is disengageable from the front cam surface in the cam groove against a biasing force of the biasing device when the cam follower is engaged in the accommodation section.

Abstract: The invention provides a zoom lens device that can include lens groups. A third lens group (compensator lens group) can be disposed between two lens groups (a second and a fourth lens groups) forming a variator lens group. The two lens groups (the second and fourth lens groups) forming the variator lens group can be retained by a common variator-lens frame and moved together. Accordingly, a zoom lens device, an optical apparatus, and a projector can be provided in which, even when a plurality of lens groups are assembled, degradation of optical characteristics due to decentering between the lens groups can be prevented.

Abstract: A retracting mechanism of a zoom lens barrel includes first, second and third lens groups, wherein the first and third lens groups are integrally moved along an optical axis during variation of a focal length, and wherein at least one of the first and third lens groups is moved relative to the other to reduce a distance therebetween when the zoom lens barrel is fully retracted. The retracting mechanism includes first, second and third lens group moving rings; a cam mechanism for independently moving the first and second lens group moving rings; a second lens group support frame; an intermediate member fixed to the second lens group support frame; and a biasing device for biasing the third lens group moving ring away from the first lens group moving ring. The biasing device functions between the intermediate member and the third lens group moving ring.

Abstract: Projector has projection optical system for projecting an image onto a projection surface and optical zoom mechanism for actuating projection optical system to enlarge and reduce the image projected onto the projection surface. Projector also has distortion correcting circuit for correcting distorted quadrilateral projected images, which are projected onto the projection surface along an optical axis that is oblique vertically and horizontally to the projection surface, into respective square corrected images, zoom setting detector for detecting a zoom setting of optical zoom mechanism, and CPU for generating corrective data to be set in distortion correcting circuit based on the zoom setting detected by zoom setting detector.

Abstract: A zoom lens barrel includes a linear guide ring which is positioned about an optical axis and includes a linear guide slot; a cam ring which is coaxially positioned around the linear guide ring and includes a cam groove; and a movable lens frame which supports a lens group and includes a cam follower which passes through the linear guide slot and engages in the cam groove. The cam ring is provided with a large ring portion, a small ring portion having a smaller diameter than the large ring portion, and a radial flange portion positioned therebetween. The cam groove is formed on both the small ring portion and the radial flange portion so that one end of the cam groove constitutes an open end at the radial flange potion, whereby the cam follower can be inserted into the cam groove through the open end.

Abstract: A cam mechanism includes a cam ring including a cam rib which is formed on a peripheral surface of the cam ring; and a follower ring which is concentric with the cam ring, the follower ring including a pair of cam followers which hold the cam rib between the pair of cam followers. Upon the cam ring and the follower ring being engaged with each other in an assembly process thereof, an inner cam follower of the pair of cam followers first approaches an end of the cam rib in a lengthwise direction thereof, and an outer cam follower of the pair of cam followers subsequently approaches the same end of the cam rib. A portion of the outer cam follower is extended outwards from a position of a peripheral surface of the inner cam follower in a circumferential direction of the follower ring.

Abstract: A retracting mechanism of a zoom lens barrel includes a first through third lens group moving rings; a first linear guide projection formed on the first lens group moving ring to be engaged in a linear guide slot from outside the second lens group moving ring, the first linear guide projection including a hanging groove formed therealong, a rear end of the hanging groove being closed; a second linear guide projection formed on the third lens group moving ring to be engaged in the linear guide slot from inside the second lens group moving ring; and a linear moving key projecting from a front end of the second linear guide projection to be engaged in the hanging groove. A rear moving limit of the third lens group moving ring is determined by contact of the linear moving key with the closed end of the hanging groove.

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 a lens-holding cylinder which supports a lens and is provided with a cam-follower and a rectilinear key; a cam-cylinder having a cam-groove which engages with the cam-follower so as to apply a driving force to the lens-holding cylinder in the optical-axis direction; and a guide cylinder which is enclosed by the cam-cylinder and has a rectilinear guide opening that engages with the rectilinear key so as to guide the lens-holding cylinder in the optical-axis direction. A segment of the cam-cylinder adjacent to an object to be photographed has a greater wall thickness such that the cam-cylinder has a level difference. A portion of the guide cylinder adjacent to an object to be photographed, which corresponds to the level difference of the cam-cylinder, is made thinner by the amount of the level difference.

Abstract: A lens apparatus which is easy to assemble, provides high strength at the flange portion, and achieves high degree of design freedom, too, is disclosed. On the circumferential wall of a second barrel member, a first groove portion is disposed to guide a guide portion provided in the first barrel member and at the end of optical axis direction of the circumferential wall, a flange portion is formed. On a third barrel member, a cam portion which engages with a cam follower portion provided on the guide portion is formed.

Abstract: A rotational state detecting device including operation rings provided so as to be rotatable about a first axis, the operation rings each being rotated by external operation; support shafts each provided so as to be rotatable about a second axis different from the first axis; disk-shaped scales each supported by a respective one of the support shafts; sensors each detecting the rotation of a respective one of the scales; and rotation transmitting mechanisms for respectively transmitting the rotation of each of the operation rings to a respective one of the support shafts.

Abstract: A zoom lens barrel includes a cam ring which is driven to rotate; a first lens frame which is positioned around the cam ring, supports a frontmost lens group of a zoom lens system, and includes a first cam follower; a light-shield exterior ring positioned around the first lens frame, and includes a second cam follower; and first and second outer cam grooves formed on an outer peripheral surface of the cam ring so that the first and second cam followers are engaged in the first and second outer cam grooves, respectively. The second cam follower is engaged in the second outer cam groove through a linear guide slot formed on the first lens frame. Zooming ranges of the first and second outer cam grooves are shaped so as to move the first lens frame and the light-shield exterior ring in the same moving path.

Abstract: A zoom lens barrel assembly includes a first lens group including first and second sub-lens groups; a second lens group; a sub-lens group switching mechanism for moving the first or second sub-lens group away from the other in a short focal length photographing range, and toward the other in a long focal length photographing range; and a zoom cam mechanism having front and rear lens group cam grooves. The rear lens group cam groove includes first and second portions corresponding to the short and long focal length photographing ranges, respectively, the first and the second portions connected to each other via a discontinuous portion. The front lens group cam groove includes a non-linear portion which corresponds to the short focal length photographing range and provides a non-linear path, and a linear portion which corresponds to the long focal length photographing range and provides a linear path.

Abstract: A lens barrel includes front and rear sub-lens groups; front and rear sub-lens group frames for supporting the front and rear sub-lens groups, respectively; a lens frame shift mechanism for causing the front sub-lens group frame and the rear sub-lens group frame to move relative to each other to obtain the mutually close position and the mutually distant position; a first lens group positioning surface provided on the front sub-lens group frame for positioning the front sub-lens group by contacting with a portion of a rear surface of the front sub-lens group; and a second lens group positioning surface provided on the rear sub-lens group frame for positioning the front sub-lens group by contacting with a portion of a front surface of the rear sub-lens group.

Abstract: A lens barrel includes a guide barrel, an outer ring, an inner ring, a cam ring and a movable lens frame, arranged in that order from outermost side, wherein the axes thereof coincide with a common optical axis, the outer ring being guided linearly in the optical axis direction by the stationary barrel, the inner ring being linearly guided in the optical axis direction by the outer ring, and the cam ring being rotatable to move the movable lens frame in the optical axis direction; and a lens barrier mechanism having an aperture positioned in front of the movable lens frame, the lens barrier mechanism being provided on a front opening of the inner ring, for opening and closing the aperture.

Abstract: For a camera lens barrel with helicoid threads, at the portion where the helicoid female thread of a fixed frame is threaded with the helicoid male thread of a rotary frame, six separation preventing pins are implanted in the portion of the helicoid male thread around the same circumference at the equal intervals. These separation presenting pins are implanted between convex thread portions of the helicoid male thread, respectively. Protruding portions of the separation preventing pins fit in and slidingly contact concave thread portions of the helicoid female thread that is threaded with the helicoid male thread in which the separation preventing pins are disposed. A contacting edge fits in and comes into sliding contact with the concave thread portion of the helicoid female thread by narrowing the circumferential surface thereof.

Abstract: A lens barrel includes a stationary barrel, an outer ring, an inner ring, a cam ring and a movable lens frame, arranged in that order from outermost side, wherein the axes thereof coincide with a common optical axis, the outer ring being guided linearly in the optical axis direction by the stationary barrel, the inner ring being linearly guided in the optical axis direction by the outer ring, and the cam ring being rotatable to move the movable lens frame in the optical axis direction; and a lens barrier mechanism having an aperture positioned in front of the movable lens frame, the lens barrier mechanism being provided on a front opening of the inner ring, for opening and closing the aperture.

Abstract: An arrangement for rotatable adjustment of a cap on an eyepiece housing with a stationary pin pointing radially outward from the eyepiece housing and a groove which is assigned to the pin, arranged on the inner side of the cap and rises in the axial direction, is characterized in that, in a plane at right angles to the longitudinal axis of the eyepiece housing, three pins are arranged on the latter, the heads of which pins have at least approximately the same spacing from the longitudinal axis, and in that the sliding bottom of the groove assigned to each pin has a smaller spacing in relation thereto, so that the cap bears against the pins under prestress.

Abstract: A retracting mechanism of a zoom lens barrel includes first, second and third lens groups, wherein the first and third lens groups are integrally moved along an optical axis during variation of a focal length, and wherein at least one of the first and third lens groups is moved relative to the other to reduce a distance therebetween when the zoom lens barrel is fully retracted. The retracting mechanism includes first, second and third lens group moving rings; a cam mechanism for independently moving the first and second lens group moving rings; a second lens group support frame; an intermediate member fixed to the second lens group support frame; and a biasing device for biasing the third lens group moving ring away from the first lens group moving ring. The biasing device functions between the intermediate member and the third lens group moving ring.

Abstract: A retracting mechanism of a zoom lens barrel includes a first through third lens group moving rings; a first linear guide projection formed on the first lens group moving ring to be engaged in a linear guide slot from outside the second lens group moving ring, the first linear guide projection including a hanging groove formed therealong, a rear end of the hanging groove being closed; a second linear guide projection formed on the third lens group moving ring to be engaged in the linear guide slot from inside the second lens group moving ring; and a linear moving key projecting from a front end of the second linear guide projection to be engaged in the hanging groove. A rear moving limit of the third lens group moving ring is determined by contact of the linear moving key with the closed end of the hanging groove.

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 zoom lens control mechanism includes a lens barrel with a lens group arranged in advance therein, a lens barrel support portion for the lens barrel seated on, a guiding device and a driving device. The lens barrel has three cylinders with the same center, and each of the cylinders has a post disposed at the bottom edge thereof and arranged with the imaginary center of the cylinders on the same line. Each of the cylinders except the innermost cylinder further has an elongated slot extended along the outer surface thereof. The guiding device is received in the two elongated slots and fixed on the innermost cylinder for leading the cylinders of the lens barrel moving relatively along the optical axis in the range of the allowable deviation. The lens barrel support portion includes three protruding cylinders which have the same center thereof for mating with the corresponding cylinders of the lens barrel.

Abstract: A lens apparatus includes four lens groups and a plurality of barrels with grooves that guide and drive the lens frames of the four lens groups in order to achieve a high zoom ratio and retraction of the lens apparatus into a camera body when the lens apparatus is not in use. Two sets of three guide grooves in a fixed barrel and three cam grooves in a cam barrel are unequally spaced around the circumference of the barrels so as to provide more room for an additional groove in the cam barrel. Some of the lens frames are fully supported by pins in the grooves and some of the lens frames are partially supported by guide rods in the lens apparatus. A single guide rod helps support two lens frames in order to save space in the lens apparatus.

Abstract: A high zoom ratio lens with a reduced number of barrel components or elements of a telescopic barrel having a light-weight outermost diameter. The zoom lens comprises first to fourth groups of lenses, a fixed barrel, a first cam barrel inside the fixed barrel, a linear barrel inside the first cam barrel, a focusing cam inside the linear barrel, and a second cam barrel outside the fixed barrel and rotatably connected to the first cam barrel. The first group of lenses move for zooming by a second—A cam in the linear barrel, and either third or fourth group of lenses move for zooming by a cam in the first cam barrel. The second group lenses move for focusing by a second—B cam in the focusing cam.

Abstract: A camera having a zooming function, including plural lens groups, a fixed frame fixed to a main body of the camera, a cam member engaging with the fixed frame so that the cam member is movable in the optical axis direction of the lens groups, and plural lens group supporting frames each engaging with the cam member and supporting each of the plural lens groups so that the lens group supporting frames may move in the optical axis direction to move the lens groups in the optical axis direction.

Abstract: A lens barrel includes a stationary barrel, first through third lens support rings, and a lens drive ring including a first guide engaged with a guide formed on the stationary barrel; an engaging portion engaged with a guide formed on the first lens support ring, the lens drive ring and the first lens support ring being relatively rotatable and integrally movable in the optical axis direction; a second guide, engaged with a guide formed on the second lens support ring, to move the second lens support ring in the optical axis direction relative to the lens drive ring via rotation of the lens drive ring; and a third guide engaged with a guide formed on the third lens support ring to move the third lens support ring in the optical axis direction relative to the lens drive ring via rotation of the lens drive ring.

Abstract: A lens barrel is provided which includes a first frame member having on an inner surface thereof a female helicoid, and a cam groove which has substantially a same lead angle as a lead angle of the female helicoid and which is deeper than the female helicoid. A second frame member is placed inside the first frame member. The second frame member includes a male helicoid engaged with the female helicoid, and a cam follower engaged with the cam groove. The first frame member is rotatable relative to the second frame member, so as to cause forward or backward movement of the second frame member.

Abstract: A cam mechanism includes a cam ring including a cam rib which is formed on a peripheral surface of the cam ring; and a follower ring which is concentric with the cam ring, the follower ring including a pair of cam followers which hold the cam rib between the pair of cam followers. Upon the cam ring and the follower ring being engaged with each other in an assembly process thereof, an inner cam follower of the pair of cam followers first approaches an end of the cam rib in a lengthwise direction thereof, and an outer cam follower of the pair of cam followers subsequently approaches the same end of the cam rib. A portion of the outer cam follower is extended outwards from a position of a peripheral surface of the inner cam follower in a circumferential direction of the follower ring.

Abstract: A cam mechanism includes a cam ring including at least one cam rib which is formed on a peripheral surface of the cam ring to extend non-linearly; and a follower ring which is concentric with the cam ring, and includes at least one pair of cam followers which are formed on a peripheral surface of the follower ring to be positioned apart from each other in an axial direction of the follower ring to hold the cam rib between the pair of cam followers. Central positions of the pair of cam followers are offset from each other in a circumferential direction of the follower ring.