Abstract: A zoom optical system comprises, in order from an object: a front lens group (GFS) having a positive refractive power; an M1 lens group (GM1) having a negative refractive power; an M2 lens group (GM2) having a positive refractive power; and an RN lens group (GRN) having a negative refractive power, wherein upon zooming, distances between the front lens group and the M1 lens group, between the M1 lens group and the M2 lens group, and between the M2 lens group and the RN lens group change, upon focusing from an infinite distant object to a short distant object, the RN lens group moves, and the M2 lens group comprises an A lens group that satisfies a following conditional expression, 1.10<fvr/fTM2<2.00, where, fvr: a focal length of the A lens group, and fTM2: a focal length of the M2 lens group in a telephoto end state.

Abstract: A zoom lens system includes: a first lens group having positive power; a second lens group having negative power; and following lens groups. The following lens groups include: a first focus lens group having negative power; and a second focus lens group having positive power, arranged adjacent to, and closer to the image than, the first focus lens group. The first and second focus lens groups move along an optical axis during focusing from an infinity focus point on a close focus point. During zooming from a wide-angle end toward a telephoto end, intervals between lens groups change with the first lens group fixed with respect to an image plane. The zoom lens system satisfies the Inequality ?0.23<f2/TTL<?0.15, where TTL is an optical total length at the telephoto end and f2 is a focal length of the second lens group.

Abstract: The lens apparatus includes an optical system, a voltage transformation unit, and an actuator. A first lens unit of the optical system is moved toward the object side during zooming from a wide-angle end to a telephoto end. The voltage transformation unit includes coils. The actuator is configured to be driven by a voltage output from the voltage transformation unit and to move a part of the lens units in the optical system during focusing. The coil is disposed at a position that is separated from a position of a most object-side surface of the optical system at the wide-angle end, toward the image side by a maximum or more moving amount of the first lens unit, and is closer to the object side than a most image-side surface of the optical system at the wide-angle end.

Abstract: A zoom optical system comprises, in order from an object: a front lens group (GFS) having a positive refractive power; an M1 lens group (GM1) having a negative refractive power; an M2 lens group (GM2) having a positive refractive power; and an RN lens group (GRN) having a negative refractive power, wherein upon zooming, distances between the front lens group and the M1 lens group, between the M1 lens group and the M2 lens group, and between the M2 lens group and the RN lens group change, upon focusing from an infinite distant object to a short distant object, the RN lens group moves, and the M2 lens group comprises an A lens group that satisfies a following conditional expression, 1.10<fvr/fTM2<2.00, where, fvr: a focal length of the A lens group, and fTM2: a focal length of the M2 lens group in a telephoto end state.

Abstract: Provided is a zoom lens including, in order from an object side to an image side: a front lens unit having a positive refractive power and configured not to move for zooming; one or two intermediate lens units having a negative refractive power as a whole and configured to move for zooming; a first rear lens unit having a negative refractive power and configured to move for zooming; a second rear lens unit having a positive refractive power and configured to move for zooming; and a third rear lens unit having a positive refractive power and configured not to move for zooming. In the zoom lens, all intervals between adjacent lens units are changed for zooming, and focal lengths of the front lens unit, the one or two intermediate lens units, the first rear lens unit, and the zoom lens at a telephoto end are appropriately set.

Abstract: A variable magnification optical system comprises, in order from an object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power and a fourth lens group G4 having negative refractive power; upon varying a magnification, a distance between the first lens group G1 and the second lens group G2 being varied, a distance between the second lens group G2 and the third lens group G3 being varied, and a distance between the third lens group G3 and the fourth lens group G4 being varied; upon focusing, the fourth lens group being moved; and a predetermined conditional expression being satisfied.

Abstract: The lens holding frame is accommodated in the outer tube and is movable with respect to the outer tube in an optical axis direction (OAD) parallel to an optical axis of a lens optical system. The intermediate holding frame is a flexible frame body that constitutes the lens holding frame, is formed of a flexible material, and has a tubular shape. The intermediate holding frame is integrally provided with beam structures as abutments. The beam structures abut onto an inner circumferential surface of the outer tube in a state of being elastically deformed such that a restoring force is generated and prevent vibration caused by a gap between an outer circumferential surface of the lens holding frame and an inner circumferential surface of the outer tube.

Abstract: Provided is a zoom lens including, in order from an object side to an image side: a positive first lens unit; a negative second lens unit; a positive third lens unit; a positive fourth lens unit; and a rear unit including at least one lens unit. An interval between each pair of adjacent lens units is changed during zooming. The first lens unit includes, in order from the object side to the image side, a negative lens and a positive lens. A focal length f1 of the first lens unit, a focal length f2 of the second lens unit, a focal length f3 of the third lens unit, and an average value Nd1ave of refractive indices at a d-line of respective materials of the negative lens and the positive lens of the first lens unit are each appropriately set.

Abstract: A zoom lens comprises four lens unit, and at the time of zooming, each of a distance between a first positive lens unit and a first negative lens unit and a distance between a second negative lens unit and a second positive lens unit changes, and a distance between the first positive lens unit and the second negative lens unit widens more at the telephoto end than at the wide angle end, and the first positive lens unit includes an object-side sub-lens unit and an image-side sub-lens unit, and an aperture stop is disposed between the object-side sub-lens unit and the image-side sub-lens unit, and the first negative lens unit includes a negative lens and a positive lens, and a refracting surface nearest to an image in the first negative lens unit is concave toward the image side, and a refracting surface nearest to an object in the second positive lens unit is concave toward the object side, and a refracting surface nearest to the image in the second positive lens unit is convex toward the image side, and the z

Abstract: A lens barrel includes a first lens frame that holds a first lens; a second lens frame that holds a second lens, and holds the first lens frame movably along an optical axis; and a pair of linear units that drive the movement of the first lens frame along the optical axis. When seen in an optical axis direction, the pair of linear units are disposed along the outer circumference of the first lens frame, at mutually non-opposing positions across the optical axis.

Abstract: The present embodiment relates to a camera module comprising: a bobbin, which has a through-hole formed therein; a lens module, which is accommodated in the through-hole and is coupled to the bobbin; a protrusion formed to protrude from the outer peripheral surface of the lens module; and a recess formed to be recessed from the inner peripheral surface of the bobbin so as to accommodate at least a part of the protrusion, wherein the recess comprises a first guide portion, which extends downwards from the upper end of the bobbin, and a second guide portion, which extends so as to slope from the first guide portion.

Abstract: A zoom optical system includes a plurality of lens units, the plurality of lens units consist of lens units having a positive refractive power and lens units having a negative refractive power, and the lens units having a positive refractive power include a positive lens unit and an image-side positive lens unit, the image-side positive lens unit is not moved, in the lens plurality of units, a space between the lens units disposed adjacently is changed at a time of zooming, at a time of focusing, or at a time of zooming and at a time of focusing, the positive lens unit includes a predetermined positive lens satisfying the following Conditional Expression (2), and the following Conditional Expression (1) is satisfied: 0.1?fGBUN1/fGPM?2.1??(1), and 60.8??dGPMP1?100.0??(2).

Abstract: A lens barrel includes at least one lens, the optical axis of the lens; the first frame (the fixed frame 900) having the first restricting portion (901, 902) and having an approximately cylindrical shape about the optical axis; the second frame (1000) having the cam groove (1036) and having an approximately cylindrical shape about the optical axis; the third frame (510) having the guide portion (511) which restricts inclination thereof with respect to the first contact portion (514) and the optical axis and having an approximately cylindrical shape about the optical axis; the drive arm (520) having a cam follower (523), the second restricting portion (524, 525) and the second contact portion (526), and having an approximately arcuate shape constituted of a portion of a circular cylinder about the optical axis or an approximately plate shape; the guide shaft (601) for guiding the guide in a movable manner in the optical axis direction; and the spring (603).

Abstract: A lens barrel includes at least one lens, the optical axis of the lens; the first frame (the fixed frame 900) having the first restricting portion (901, 902) and having an approximately cylindrical shape about the optical axis; the second frame (1000) having the cam groove (1036) and having an approximately cylindrical shape about the optical axis; the third frame (510) having the guide portion (511) which restricts inclination thereof with respect to the first contact portion (514) and the optical axis and having an approximately cylindrical shape about the optical axis; the drive arm (520) having a cam follower (523), the second restricting portion (524, 525) and the second contact portion (526), and having an approximately arcuate shape constituted of a portion of a circular cylinder about the optical axis or an approximately plate shape; the guide shaft (601) for guiding the guide in a movable manner in the optical axis direction; and the spring (603).

Abstract: A zoom lens system, in order from an object side to an image side, includes: a first lens group having positive optical power; a second lens group having negative optical power; a third lens group having positive optical power; a fourth lens group having negative optical power; and a fifth lens group having positive optical power, wherein focusing is performed by moving the fourth lens group, and conditions (1) through (3) are satisfied: ?d/(fT×tan ?T)<3.5??(1) LT/fT<1.1??(2) 9.1<fT/fW??(3) where ?d is a total thickness of each of the lens groups, ?T is a half angle of view at the telephoto end, fW is a focal length at the wide angle end, fT is a focal length at the telephoto end, and LT is an optical total length at the telephoto end.

Abstract: An imaging lens assembly is provided in the present disclosure. The imaging lens assembly includes a front fixing unit with a first lens, a triangular prism, a magnification unit with a second lens, an aperture stop, a compensation unit with a third lens and a fourth lens, and an object lens unit with a fifth lens, which are arranged in that order along an light incident direction. The triangular prism is configured for changing a light transmitting direction, the magnification unit and the compensation unit are configured for performing continuous focal length switching, and the object lens unit is configured for performing focusing in different distance conditions. The first lens is a meniscus convex lens, the second lens is a biconvex positive lens, the third lens is a biconcave lens, the fourth lens is a meniscus convex lens, and the fifth lens is a biconvex lens.

Abstract: An optical instrument comprises a control section for driving a lens group in an optical axis direction, a first position detection section for detecting an absolute position of the lens group, a second position detection section for detecting a relative position of the lens group, and a storage section for storing first data corresponding to output of the second position detection section corresponding to a specified position, and second data corresponding to a target position, wherein, the control section acquires output of the second position detection section, at a point when a specified variation has occurred, as third data, calculates a stop target position based on the first data and the third data and executes a stop operation for the lens group to stop the lens group, and corrects output of the second position detection section in a state, based on the second data, and the stop target position.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, and a rear lens group including one or more lens units. The distance between adjacent lens units changes during zooming. The first lens unit is closer to the object side at a telephoto end than at the wide-angle end. The second lens unit includes a first negative lens, a second negative lens, and a third negative lens in this order from the object side. The focal lengths of the zoom lens at the wide-angle end and at the telephoto end, the focal length of the first lens unit, and the focal length of the second lens unit are appropriately set based on predetermined mathematical conditions.

Abstract: A zoom lens optical system includes, in order from an object side along an optical axis: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having negative refractive power; and a fifth lens group having positive refractive power, wherein upon zooming from a wide-angle end state to a telephoto end state, the first lens group being moved with respect to an image plane, a distance between the first lens group and the second lens group increasing, a distance between the second lens group and the third lens group decreasing, a distance between the third lens group and the fourth lens group varying, and a distance between the fourth lens group and the fifth lens group varying.

Abstract: A zoom lens includes, in order from an object side to an image surface side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power, the second lens group and the third lens group are moved such that the second lens group is located on a most object side at a wide-angle end and the third lens group is located on a most image surface side at a telephoto end during zooming.

Abstract: A zoom lens system, in order from an object side to an image side, comprising: a first lens unit having positive optical power; a second lens unit having negative optical power; a third lens unit having positive optical power; a fourth lens unit having negative optical power; a fifth lens unit; and a sixth lens unit, wherein in zooming from a wide-angle limit to a telephoto limit at a time of image taking, the first lens unit, the second lens unit, the third lens unit, and the fourth lens unit move along an optical axis so that an interval between the third lens unit and the fourth lens unit at the telephoto limit is larger than that at the wide-angle limit, and wherein focusing from an infinity in-focus condition to a close-object in-focus condition is performed by moving the fourth lens unit along the optical axis.

Abstract: A varifocal lens barrel includes a plurality of lens groups, each of which are linearly movable in the optical axis direction thereof without rotating about the optical axis during a zooming operation and during a focusing operation, including a base barrel which is linearly movable in the optical axis direction by rotation of a zoom operational ring, wherein lens frames of the respective lens groups are each supported by the base barrel.

Abstract: A zoom lens assembly includes a focus lens group; a focus motor moving the focus lens group in a zooming operation; a plurality of zoom lens groups; a zoom motor moving the zoom lens groups in a focusing operation; a zoom gear train; a first transmission gear; a second transmission gear; and a transmission element, wherein when a withdrawing operation is performed, the focus lens group is rotated by the zoom motor through the zoom gear train, the first transmission gear, the second transmission gear, and the transmission element so as to avoid the zoom lens group.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit of a positive refractive power, a second lens unit of a negative refractive power, a reflective unit configured to bend an optical axis, and a rear lens group including two or more lens units, the reflective unit being stationary during zooming, the first and second lens units and two or more lens units of the rear lens group being moved during zooming, wherein the following conditions are satisfied: 4.3<?2t/?2w<12.0, and 2.1<?Rt/?Rw<3.0, where ?2w and ?2t denote lateral magnifications of the second lens unit at a wide-angle end and a telephoto end, respectively, and ?Rw and ?Rt denote lateral magnifications at the wide-angle end and the telephoto end, respectively, of a lens unit having a greatest variable power contribution out of the rear lens group.

Abstract: A zoom lens includes, a first lens unit of a positive refractive power, a second lens unit of a negative refractive power, a reflective element, and a rear lens group including two or more lens units and an aperture stop, in which the first lens unit, the second lens unit, and two or more lens units of the rear lens group are moved while the reflective element is stationary during zooming, wherein movement amounts M1 and M2 of the first and second lens units during zooming, a movement amount Ms of the aperture stop, and focal lengths fw and ft of the entire zoom lens at the wide-angle end and the telephoto end, respectively, lateral magnifications ?2w and ?2t of the second lens unit, a distance LSw from the first lens surface to the aperture stop at the wide-angle end are appropriately set.

Abstract: A zoom lens includes a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group which has negative refractive power and is configured with only a single lens, and a fifth lens group having positive refractive power, which are arranged in order from an object side to an image side. During zooming, at least the first lens group, the second lens group, the third lens group, and the fourth lens group are movable in an optical axis direction. Focusing from infinity to a close range is performed by the fourth lens group being moved in the optical axis direction. At least one of following conditional expressions (1) and (2) is satisfied. ?11.0<Fno—w×Y/{(1??4—w2)×?5—w2}<?7.0 and??(1) ?11.0<Fno—t×Y/{(1??4—t2)×?5—t2}<?7.

Abstract: A zoom lens adjustment structure includes a substrate, a focus device and a driving device. The focus device is mounted on the substrate, and includes a stationary lens barrel, a outside guide lens barrel, and a cam lens barrel. The outside guide lens barrel is received in the stationary lens barrel, the cam lens barrel is set at the inner side of the outside guide lens barrel, and plurality of active lens barrels are sandwiched between the outside guide lens barrel and the cam lens barrel. The active lens barrel includes a lens set. The driving device includes a motor and a gear group, which is positioned laterally to the stationary lens barrel, to drive the focus device adjusting the position of the active lens.

Abstract: A zoom lens includes a fixing barrel, a cam barrel, a guide barrel, a first lens group, a second lens group, and a third lens group. The cam barrel is rotatably received in the fixing barrel. The guiding barrel is movably received in the fixing barrel and partially receives the cam barrel. The guiding barrel is moveable along an optical axis of the zoom lens following the motion of the cam barrel. The first lens group is rotatably received in the guiding barrel. The second lens group is rotatably received in the cam barrel. The first and second lens groups move along the optical axis following the rotation of the cam barrel. The third lens group is aligned with the first and second lens groups, and driven by a driver to be movably received in the fixing barrel and moveable along the optical axis of the zoom lens.

Abstract: A zoom lens comprises a first lens unit G1 having a positive refractive power, a second lens unit G2 having a negative refractive power, a third lens unit G3 having a positive refractive power, a fourth lens unit G4 having a negative refractive power, a fifth lens unit G5, and a sixth lens unit G6 having a positive refractive power. Zooming from a wide angle end to a telephoto end is carried out by changing a distance between the lens units, and a distance between the first lens unit G1 and the third lens unit G3 narrows at the telephoto end than at the wide angle end, and the first lens unit G1 is stationary at the time of zooming from the wide angle end to the telephoto end, and lens units from the second lens unit G2 to the fifth lens unit G5 move.

Abstract: Zoom lens assembly formed of a number of lens groups on a track. The lens groups can be moved on the track to form different lens effects such as zoom. The devices sense an end of travel in one direction using a hardware device. All the positions are relative to that end of travel, based on values stored in a memory, and by using the memory to drive the lens groups on the track.

Abstract: A zoom lens includes a first lens unit, a second lens unit, a third lens unit, a fourth lens unit and a fifth lens unit. In the zoom lens, air intervals L2w, L3w between the second lens unit and the third lens unit and between the third lens unit and the fourth lens unit at a wide-angle end, a focal length f1 of the first lens unit, a combined focal length f23w of the second lens unit and the third lens unit at the wide-angle end, a focal length fw of the whole system at the wide-angle end, a zoom ratio Z, and a smallest value L2z1a of the air interval between the second lens unit and the third lens unit in a wide angle zoom range in which a magnification-varying ratio relative to that at the wide-angle end ranges from Z0.02 to Z0.35 are appropriately set.

Abstract: A zoom lens adjustment structure includes a substrate, a focus device and a driving device. The focus device is mounted on the substrate, and includes a stationary lens barrel, a outside guide lens barrel, and a cam lens barrel. The outside guide lens barrel is received in the stationary lens barrel, the cam lens barrel is set at the inner side of the outside guide lens barrel, and plurality of active lens barrels are sandwiched between the outside guide lens barrel and the cam lens barrel. The active lens barrel includes a lens set. The driving device includes a motor and a gear group, which is positioned laterally to the stationary lens barrel, to drive the focus device adjusting the position of the active lens.

Abstract: A zoom lens barrel assembly includes: a first zoom ring comprising a first protrusion; a guide ring disposed around the first zoom ring comprising a first guide slot through which the first protrusion passes, and a second guide slot; a second zoom ring comprising a second protrusion, and movable in an axial direction; a first cylinder comprising a guide groove into which the second protrusion inserts, and a third protrusion passing through the second guide slot, and disposed between the first and second zoom rings; a second cylinder disposed around the guide ring comprising a fourth protrusion, a first groove portion into which the first protrusion inserts, and a second groove portion into which the third protrusion inserts, and supporting the first zoom ring and the first cylinder; and an external cylinder disposed around the second cylinder and comprising a third groove portion into which the fourth protrusion inserts.

Abstract: A zoom lens includes a first lens unit, a second lens unit, a third lens unit and a fourth lens unit. The third lens unit includes a movable barrel, a first slidable member able to move in a first direction perpendicular to the optical axis, and a second slidable member able to move along a second direction perpendicular to the optical axis and also perpendicular to the first direction. The movable barrel includes a first Hall member and a first coil, the first slidable member comprises a second Hall member and a second coil. A first magnet is aligned with the first coil, and a second magnet is aligned with the second coil, both coils can be independently energized to compensate any shaking movements experienced by the Hall members.

Abstract: A lens barrel includes a zoom optical system in which a focal distance is changeable; a first group frame moving together with the first lens group; and first and second cam mechanisms transmitting drive force to the first group frame. In a zoom region, each of a first group cam groove and a cam slot includes a first section, a second section which adjoins the first section and has an absolute value of a gradient smaller than that of the first section, and the third section which adjoins the second section and has the absolute value of the gradient larger than that of the second section, and in which a sign of the gradient is the same as that of the first section. A distance from an imaging surface to the first group frame in the optical axis direction has a local minimum in the second section.

Abstract: A lens barrel is provided that includes a zoom optical system, a zooming unit, and a light adjusting mechanism. The zoom optical system is configured to form an optical image of a subject and includes a first, a second, and a third lens group. The third lens group is movable and configured to move the optical image. The zooming unit causes the zoom optical system to perform a zooming operation. The light adjusting mechanism is configured to adjust the light passing through the zoom optical system. The lens barrel is configured to change between an imaging state and a retracted state. In the imaging state, the zooming operation is performed, and the first, the second, and the third lens groups are in alignment. During the zooming operation, the second lens group moves integrally with the third lens group along the optical axis, and the light adjusting mechanism and the second lens group move independently of one another along the same axial direction.

Abstract: Providing a zoom lens system having a high zoom ratio being compact with high optical performance. The system includes, in order from an object along an optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, at least one lens group having positive refractive power, and an n-th lens group GN being disposed to the most image side. The n-th lens group GN with positive refractive power includes, in order from the object, a front group GNa and a rear group GNb having positive refractive power. Focusing on an object is carried out by moving the rear group GNb along the optical axis, and a given conditional expression is satisfied.

Abstract: A lens apparatus includes a first lens unit and a second lens unit each of which is configured to move in an optical axis direction, a first cam tube that includes a first cam part and a second cam part respectively on an outer circumferential surface and an inner circumferential surface and moves the first and second lens units respectively in the optical axis direction using the first and second cam parts as the first cam tube rotates around an optical axis, and a linearly moving guide tube that is arranged on an inner circumferential side of the first cam tube and configured to guide the first and second lens units in the optical axis direction.

Abstract: A zoom lens includes a first lens unit, a second lens unit, a third lens unit and a fourth lens unit. The third lens unit includes a movable barrel, a first slidable member able to move in a first direction perpendicular to the optical axis, and a second slidable member able to move along a second direction perpendicular to the optical axis and also perpendicular to the first direction. The movable barrel includes a first Hall member and a first coil, the first slidable member comprises a second Hall member and a second coil. A first magnet is aligned with the first coil, and a second magnet is aligned with the second coil, both coils can be independently energized to compensate any shaking movements experienced by the Hall members.

Abstract: A zoom lens includes, from an object side to an image side, first to fifth lens units having positive, negative, positive, negative, and positive refractive powers. A distance between the first and second lens units is longer, a distance between the second and third lens units is shorter, and a distance between the fourth and fifth lens units is longer at a telephoto end than at a wide angle end, and a distance between the third and fourth lens units differs between the telephoto end and the wide angle end. Focal lengths of the first and fourth lens units and the entire zoom lens at the wide angle end, a moving amount of the first lens unit during zooming, and a distance from a lens surface closest to the object side in the first lens unit to an image plane at the wide angle end are set properly.

Abstract: A vibration actuator having excellent driving performance, a method for manufacturing the vibration actuator, a lens barrel and a camera. The vibration actuator is provided with: an electromechanical conversion element which converts an electric energy into a mechanical energy; an elastic body which generates vibration waves by oscillation of the electromechanical conversion element; a resin layer, which is formed of a conductive thermoplastic resin and bonds the electromechanical conversion element and the elastic body with each other; and a relatively moving member which is brought into contact with the elastic body with a pressure and is relatively moved to the elastic body by vibration waves.

Abstract: Providing a zoom lens system having a vibration reduction function capable of performing quick focusing with excellent optical performance even upon vibration reduction. The system including, in order from an object, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, and a fourth lens group G4 having positive refractive power. Upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group G1 and the second lens group G2 varies, and a distance between the second lens group G2 and the third lens group G3 varies. The third lens group G3 carries out focusing from an infinity object to a close object. At least a portion of the fourth lens group G4 moves in a direction perpendicular to the optical axis.

Abstract: A lens barrel includes a first zoom/focus lens group and a second zoom/focus lens group configured to respectively vary a focal distance and imaging distance by moving in an optical axis, a first actuator configured to drive the first zoom/focus lens group, and a second actuator configured to drive the second zoom/focus lens group.

Abstract: A zoom lens system comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, a fourth lens unit having negative optical power, and a fifth lens unit having positive optical power, wherein the third lens unit includes at least one lens element having positive optical power and at least one lens element having negative optical power, at least the first to third lens units are moved along an optical axis in zooming so that air spaces between the respective lens units vary, thereby performing magnification change, a lens unit positioned on the image side relative to an aperture diaphragm is moved along the optical axis in focusing, and the conditions: 4.0<D/Ir<5.3 and Z=fT/fW?9.

Abstract: Systems and methods to position most precisely a lens system of an optical device are disclosed. Embodiments of these electrical sensors comprise capacitive sensors, inductive sensors and resistive sensors to measure the actual position of a lens system with a precision of at least 1 ?m. Read-out circuits using double-correlated sampling structures are providing the position signals from the electrical sensors to a controller. The controller compares the actual position signals with a set-signal representing a target position of the lens signal and issues a signal to a motor to get the lens system moved to the target position. A variety of motors/actuators can be used to move a slider carrying the lens system to the position desired.

Abstract: A zoom lens includes a fixing barrel, a cam barrel, a guide barrel, a first lens group, a second lens group, and a third lens group. The cam barrel is rotatably received in the fixing barrel. The guiding barrel is movably received in the fixing barrel and partially receives the cam barrel. The guiding barrel is moveable along an optical axis of the zoom lens following the motion of the cam barrel. The first lens group is rotatably received in the guiding barrel. The second lens group is rotatably received in the cam barrel. The first and second lens groups move along the optical axis following the rotation of the cam barrel. The third lens group is aligned with the first and second lens groups, and driven by a driver to be movably received in the fixing barrel and moveable along the optical axis of the zoom lens.

Abstract: A zoom lens device includes a focusing lens group arranged on an object side, and a variator lens group next thereto, and a temperature sensor. The focusing lens group includes a focusing lens, and a temperature-based correction lens for correcting changes in focal point caused by temperature changes around the focusing lens group. The temperature-based correction lens is moved by a temperature-based correction lens driving mechanism along an optical axis to a position determined by a temperature detected by the temperature sensor, independently of the positions of the focusing lens or variator lens group. Thereby, the zoom lens device is capable of favorably correcting defocus of the lens group caused by an ambient temperature change with a simple correcting mechanism.

Abstract: The projecting zoom lens includes, sequentially from its magnification side, a negative first lens group, a positive second lens group, a negative third lens group, a positive fourth lens group, a positive or negative fifth lens group, and a positive six lens group, while the reduction side of the projecting zoom lens is formed as a telecentric system. When the power of the zoom lens is varied, the first lens group and sixth lens group are fixed, while the second to fifth lens groups move. In such power varying operation, the movement of the third lens group advances from the magnification side to the reduction side as the zoom lens goes from the wide angle end toward the tele end.

Abstract: A lens barrel includes: a variable focal length lens system including at least three movable lens groups; and guiding means for moving the variable focal length lens system forward and backward in an optical axis direction. The variable focal length lens system includes at least first, second and third lens groups having positive, negative and positive refracting power, respectively, arranged in this order from an object side. When a lens position setting is changed from a wide angle end state to a telescopic end state, at least the first and third lens groups are moved toward the object side such that air separation between the first and second lens groups monotonically increases and air separation between the second and third lens groups monotonically decreases. The guiding means includes a fixed frame, a rotating frame, a rectilinear guiding frame, a first guide frame, and a second guide frame.

Abstract: A prism type of lens includes a first reflection lens, at least a first lens group, a second reflection prism, at least a second lens group, a third reflection prism, and at least a third lens group sequentially arranged from an object side to an image side. Light is reflected by the reflection prisms to form a bent light axis. Therefore, the optical axis has three sections for the lens groups to move respectively. The bent light axis has a longer distance that the lens of the present invention may have a great zoom range.