Zoom lens barrel and camera incorporating such barrel
First Claim
1. A zoom lens barrel adapted to be attached to a camera having an optical axis, said zoom lens barrel comprising a stationary barrel and a rotatable cam ring which is adapted to be driven by means for driving said cam ring, said driving means being stationary along the optical axis of said camera, said cam ring being movably supported by said stationary barrel for movement along said optical axis, during zooming operation of front and rear movable lens groups, in association with rotation of said cam ring, said cam ring including at least two cam grooves which are adapted to receive said front and rear movable lens groups, wherein the axial positions of said movable lens groups, wherein the axial positions of said movable lens groups are at least partially determined by said cam grooves, said zoom lens barrel further comprising helicoidal connecting means for connecting said cam ring and said stationary barrel.
3 Assignments
0 Petitions
Reexamination
Accused Products
Abstract
A zoom lens barrel is disclosed with includes a stationary barrel. A rotatable cam ring is supported by the stationary barrel and is adapted to move along an optical axis direction in association with rotation of the rotatable cam ring. A lens guide ring is adapted to move together with the cam ring along the optical axis direction, and the cam ring is adapted to rotate relative to the lens guide ring, in association with axial movement of the cam ring. Cam grooves are provided for guiding the movement of at least two movable front and rear lens groups, with at least one groove being formed on the cam ring. Lens guide grooves are formed on the lens guide ring and are adapted to correspond to the cam grooves of the cam ring. At least one guide pin is provided which is adapted to extend through an associated cam groove and an associated lens guide groove. The cam grooves and lens guide grooves are shaped such that the movable lens groups can be moved along a predetermined track by the movement which results from axial movement and relative rotation of the cam ring and the lens guide ring.
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Citations
155 Claims
- 1. A zoom lens barrel adapted to be attached to a camera having an optical axis, said zoom lens barrel comprising a stationary barrel and a rotatable cam ring which is adapted to be driven by means for driving said cam ring, said driving means being stationary along the optical axis of said camera, said cam ring being movably supported by said stationary barrel for movement along said optical axis, during zooming operation of front and rear movable lens groups, in association with rotation of said cam ring, said cam ring including at least two cam grooves which are adapted to receive said front and rear movable lens groups, wherein the axial positions of said movable lens groups, wherein the axial positions of said movable lens groups are at least partially determined by said cam grooves, said zoom lens barrel further comprising helicoidal connecting means for connecting said cam ring and said stationary barrel.
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3. A zoom lens barrel adapted to be attached to a camera having an optical axis, said zoom lens barrel comprising a stationary barrel and a rotatable cam ring which is adapted to be driven by means for driving said cam ring, said driving means being stationary along the optical axis of said camera, said cam ring being movably supported by said stationary barrel for movement along said optical axis, during zooming operation of front and rear movable lens groups, in association with rotation of said cam ring, said cam ring including at least two cam grooves which are adapted to receive said front and rear moveable lens groups, wherein the axial positions of said moveable lens groups are at least partially determined by said cam grooves, and further wherein each of said cam grooves includes a zooming section within which said movable lens groups are adapted to be moved along a predetermined track, and a macro-transferring section in which said movable lens groups are adapted to be moved from one extreme zooming position to a macro-photographing range, wherein said zooming section and said macro-transferring section have lead angles which are oppositely disposed to each other with respect to said optical axis.
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4. A zoom lens barrel assembly adapted to be attached to a camera having an optical axis, said barrel assembly comprising:
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(a) a stationary barrel; (b) a rotatable cam ring adapted to be supported by said stationary barrel so as to be movable along the direction of said optical axis during zooming operation of front and rear movable lens groups, in association with rotation of said cam ring, and means for driving said cam ring, said driving means being stationary along the optical axis; (c) a lens guide ring which is movable along said optical axis direction, said lens guide ring and said cam ring being adapted to rotate relative to each other in association with axial movement of said cam ring; (d) at least two cam grooves adapted to receive said front and rear movable lens groups, at least one of said cam grooves being located on said cam ring; (e) at least one lens guide groove on said lens guide ring; and (f) at least one guide pin which is adapted to extend through one cam groove and an associated lens guide groove, wherein said cam grooves and said lens guide groove comprise means for guiding movement of said movable lens groups along a predetermined path in association with axial movement and relative rotation of said cam ring and said lens guide ring. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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- 18. A zoom lens barrel adapted to be used in a camera having an optical axis, said zoom lens barrel having a stationary barrel, said barrel having an inner surface with a plurality of guide grooves for receiving a lens guide ring, said lens guide ring including a guide plate attached to said lens guide ring having guide projections which are adapted to be fitted into said guide grooves, wherein at least one of said guide projections is elastically deformable in the direction of the width of said barrel guide grooves, a rotatable cam ring which is adapted to be supported by said stationary barrel so as to move along said optical axis in association with rotation of said cam ring, said lens guide ring being adapted to be moved together with said cam ring along said optical axis, said lens guide ring and said cam ring being provided with grooves for receiving at least front and rear movable lens groups, said movable lens groups each having guide pins which extend through said cam ring grooves and said lens guide ring grooves, wherein said grooves are shaped so as to comprise means for moving said lens groups along a predetermined track in association with axial movement and relative rotation of said cam ring and said lens guide ring.
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20. A drive mechanism for a zoom lens comprising
(a) a stationary barrel which is adapted to be secured to a camera body having an optical axis, said barrel including a female helicoid; -
(b) a cam ring having a male helicoid which is adapted to be engaged by said female helicoid; (c) a cam ring gear which extends along teeth of said cam ring male helicoid; (d) a cam ring driving mechanism having a driving gear which is adapted to be engaged by said cam ring gear; (e) a lens guide ring which is adapted to move, together with said cam ring, along said optical axis, wherein said lens guide ring and said cam ring are adapted to rotate, relative to each other, in association with axial movement of said cam ring; and (f) at least two movable lens groups which are adapted to be supported by said cam ring and said lens guide ring to move with respect to each other along said optical axis, in association with axial movement and relative rotation of said cam ring and said lens guide ring along a predetermined track, to thereby comprise means for changing a focal length of said zoom lens. - View Dependent Claims (21, 22, 23, 24)
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- 25. A zoom lens barrel comprising a stationary barrel having a female helicoid and a rotatable barrel having a male helicoid which is adapted to be engaged by said female helicoid, said female helicoid having a cutaway portion for separating engagement of said male and female helicoids at a predetermined angular position of said rotatable barrel, wherein at least one of said female and male helicoids has teeth which are adjacent to said cutaway portion, said adjacent teeth having end faces with tapered surfaces which gradually increase the width of at least one helicoid groove defined by said adjacent teeth.
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28. A zoom lens comprising:
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(a) a stationary barrel which is adapted to be secured to a camera body having an optical axis; (b) a cam ring supported by said stationary barrel for movement along the optical axis of a camera in association with rotation of said cam ring; (c) a lens guide ring adapted to move together with said cam ring along said optical axis, said cam ring and said lens guide ring being adapted to rotate relative to each other in association with axial movement of said cam ring; (d) at least two movable lens groups which are adapted to be supported by said cam ring and said lens guide ring to move, with respect to each other, along said optical axis in association with axial movement and relative rotation of said cam ring and said lens guide ring along a predetermined track, so as to comprise means for changing a focal length of said zoom lens; and (e) a flange back adjusting mechanism comprising an outer ring adapted to be attached to said stationary barrel, between said barrel and said cam ring, said outer ring being rotatably adjustable, said mechanism further comprising means for threadably engaging said outer ring with said cam ring. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A zoom lens adapted for use with a camera having an optical axis, said zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, said cam ring having an outer periphery, and a cam ring gear being positioned about said outer periphery, wherein said cam ring outer periphery is generally cylindrical, and wherein said gear is positioned at a predetermined angle of inclination about said cam ring outer periphery.
- 39. A zoom lens adapted for use with a camera having an optical axis, said zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, said cam ring having an outer periphery, and a cam ring gear being positioned about said outer periphery, wherein said cam ring gear is spirally positioned about said cam ring outer periphery.
- 41. A zoom lens adapted for use with a camera having an optical axis, said zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, said cam ring having an outer periphery, and a cam ring gear being positioned about said outer periphery, said cam ring being generally cylindrical, with a substantially circular cross-section, said cam ring gear being inclined with respect to said cross-section.
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42. A zoom lens adapted for use with a camera having an optical axis, said zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with resect to said optical axis, said cam ring having an outer periphery, and a cam ring gear being positioned about said outer periphery, said zoom lens being usable in combination with said driving means, said driving means comprising a motor, wherein said cam ring gear is rotatably driven by a gear train, said gear train being driven by said motor.
- 52. A zoom lens adapted for use with a camera having an optical axis, a zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, said zoom lens further comprising a stationary barrel, said cam ring being rotatably positioned within said stationary barrel, said cam ring having at least one cam ring groove which has at least one groove section which is inclined with respect to said optical axis, said at least one cam ring groove comprising at least part of said means for moving said at least one lens along said optical axis, such that when said cam ring is rotated, said cam ring moves said at least one lens along said optical axis, and when said cam ring is moved linearly, said cam ring also moves said at least one lens along said optical axis, wherein said at least one lens is positioned within a shutter block, with a cam ring groove-engaging pin being connected to said shutter block.
- 54. A zoom lens adapted for use with a camera having an optical axis, a zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, said zoom lens further comprising a stationary barrel, said cam ring being rotatably positioned within said stationary barrel, said cam ring having at least one cam ring groove which has at least one groove section which is inclined with respect to said optical axis, said at least one cam ring groove comprising at least part of said means for moving said at least one lens along said optical axis, such that when said cam ring is rotated, said cam ring moves said at least one lens along said optical axis, and when said cam ring is moved linearly, said cam ring also moves said at least one lens along said optical axis, wherein said at least one lens comprises first and second lens groups, each of said lens groups being positioned within a frame having at least one pin connected to said frame, each of said lens groups thereby being guided by at least one pin along a respective cam ring groove.
- 58. A zoom lens adapted for use with a camera having an optical axis, a zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, said zoom lens further comprising a stationary barrel, said cam ring being rotatably positioned within said stationary barrel, said cam ring having at least one cam ring groove which has at least one groove section which is inclined with respect to said optical axis, said at least one cam ring groove comprising at least part of said means for moving said at least one lens along said optical axis, such that when said cam ring is rotated, said cam ring moves said at least one lens along said optical axis, and when said cam ring is moved linearly, said cam ring also moves said at least one lens along said optical axis, wherein said cam ring groove has at least three sections for guiding movement of said at least one lens, said three sections comprising a zooming section for moving said at least one lens along a predetermined track, a macro transfer section for moving said at least one lens from an extreme zooming position into a macro-photographing position, and a lens accommodation section in which said at least one lens is moved into an inoperative, retracted position.
- 62. A zoom lens adapted for use with a camera having an optical axis, a zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, and zoom lens further comprising a stationary barrel, said cam ring being rotatably positioned within said stationary barrel, said cam ring having at least one cam ring groove which has at least one groove section which is inclined with respect to said optical axis, said at least one cam ring groove comprising at least part of said means for moving said at least one lens along said optical axis, such that when said cam ring is rotated, said cam ring moves said at least one lens along said optical axis, and when said cam ring is moved linearly, said cam ring also moves said at least one lens along said optical axis, said cam ring further comprising a lens guide ring positioned concentrically within said cam ring, said lens guide ring including at least one lens guide ring groove for guiding movement of at least one lens.
- 70. A zoom lens adapted for use with a camera having an optical axis, a zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, and driving means being stationary with respect to said optical axis, said zoom lens further comprising a stationary barrel, said cam ring being rotatably positioned within said stationary barrel, said cam ring having at least one cam ring groove which has at least one groove section which is inclined with respect to said optical axis, said at least one cam ring groove comprising at least part of said means for moving said at least one lens along said optical axis, such that when said cam ring is rotated, said cam ring moves said at least one lens along said optical axis, and when said cam ring is moved linearly, said cam ring also moves said at least one lens along said optical axis, wherein said cam ring includes a plurality of grooves, said at least one lens comprises first and second lens groups, and a linearly movable lens guide ring is positioned within said cam ring, said lens guide ring including a plurality of lens guide ring grooves.
- 73. A zoom lens adapted for use with a camera having an optical axis, said zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, wherein said rotatable cam ring engages an adjacent concentric ring which is rotatable with said cam ring.
- 75. A zoom lens adapted for use with a camera having an optical axis, said zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, wherein said rotatable cam ring is positioned concentrically about a linearly movable ring having at least one groove.
- 83. A zoom lens adapted for use with a camera having an optical axis, said zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and movable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, said at least one lens comprising front and rear lens groups, wherein said rear lens group is movably guided by at least one groove in at least one substantially linearly movable member.
- 90. A zoom lens adapted for use with a camera having an optical axis, said zoom lens comprising a cam ring, at least one lens, and means for holding said lens, said cam ring being rotatable and moveable linearly along the direction of said optical axis, wherein said cam ring comprises means for moving said at least one lens and said means for holding said lens along said optical axis, in response to operation of means for driving said cam ring, said driving means being stationary with respect to said optical axis, wherein said at least one lens comprises front and rear lens groups, said cam ring being concentrically positioned about a linearly movable and non-rotatable ring which is adapted to guide at least said rear lens group.
- 101. A zoom lens adapted for use with a camera having an optical axis, said zoom lens comprising a cam ring, at least one lens, and means for connecting said at least one lens to said cam ring in order to axially move said zoom lens, said cam ring having a peripheral surface, at least one cam groove, and a cam ring gear positioned about said peripheral surface, said cam ring being generally cylindrical, with a generally circular cross-section, said gear being inclined with respect to said cross-section.
- 112. A zoom lens apparatus adapted for use with a camera having an optical axis, said zoom lens apparatus including a movable front lens group and a movable rear lens group, said lens groups being housed within a stationary barrel, said lens groups being moved along said optical axis, during zooming movement of said movable lens groups, in response to linear and rotational movement of a ring assembly along said optical axis, said linear movement of said ring assembly being effected by rotational movement of said ring assembly, said ring assembly being driven by driving means which is stationary along said optical axis, wherein said ring assembly comprises at least one rotatable ring having at least one groove, at least one of said lens groups having a pin attached to said lens group, said pin being engageable by said at least one groove, wherein said ring assembly further comprises at least one linearly movable ring which is movable only along said optical axis, said linearly movable ring having at least one groove which also engages said pin, said ring grooves together defining a path of movement of said at least one lens group.
- 116. A zoom lens apparatus adapted for use with a camera having an optical axis, said zoom lens apparatus including a movable front lens group and a movable rear lens group, said lens groups being housed within a stationary barrel, said lens groups being moved along said optical axis, during zooming movement of said movable lens groups, in response to linear and rotational movement of a ring assembly along said optical axis, said linear movement of said ring assembly being effected by rotational movement of said ring assembly, said ring assembly being driven by a driving means which is stationary along said optical axis, said ring assembly including at least one rotatable ring which comprises a generally cylindrical cam ring having at least one groove, said at least one groove being inclined with respect to said optical axis and the periphery of said cam ring, wherein both said front and rear lens groups have pins attached to said lens groups, said pins being engaged by respective cam ring grooves.
- 118. A zoom lens apparatus adapted for use with a camera having an optical axis, said zoom lens apparatus including a movable front lens group and a movable rear lens group, said lens groups being housed within a stationary barrel, said lens groups being moved along said optical axis, during zooming movement of said movable lens groups, in response to linear and rotational movement of a ring assembly along said optical axis, said linear movement of said ring assembly being effected by rotational movement of said ring assembly, said ring assembly being driven by a driving means which is stationary along said optical axis, said ring assembly including at least one rotatable ring which comprises a generally cylindrical cam ring having at least one groove, said at least one groove being inclined with respect to said optical axis and the periphery of said cam ring, wherein said cam ring has an exterior surface with a cam ring gear attached thereto, said cam ring gear being inclined with respect to said cam ring periphery.
- 120. A zoom lens apparatus adapted for use with a camera having an optical axis, said zoom lens apparatus including a movable front lens group and a movable rear lens group, said lens groups being housed within a stationary barrel, said lens groups being moved along said optical axis, during zooming movement of said movable lens groups, in response to linear and rotational movement of a ring assembly along said optical axis, said linear movement of said ring assembly being affected by rotational movement of said ring assembly, said ring assembly being driven by a driving means which is stationary along said optical axis, said ring assembly including at least one rotatable ring which comprises a generally cylindrical cam ring having at least one groove, said at least one groove being inclined with respect to said optical axis and the periphery of said cam ring, said inclined groove including a first section inclined in one direction with respect to said optical axis and a second section inclined in a second, generally opposite direction with respect to said optical axis.
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122. A female helicoid ring adapted for use in a zoom lens camera, said ring comprising:
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(a) a generally cylindrical body; (b) a plurality of generally helical, parallel threads on an internal peripheral surface of said body; (c) a recess of said interior surface; and (d) an electrically conductive brush having a base and a plurality of flexible bristles, said base being attached to said recess. - View Dependent Claims (123, 124, 125)
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- 126. A lens barrel adapted to be used in a camera having an optical axis and a zoom lens, said lens barrel comprising a stationary barrel having an inner surface with a plurality of guide grooves which are adapted to receive a member for guiding lens movement, said member including a guide plate having a plurality of guide projections which are adapted to be fitted into said guide grooves, wherein at least one of said guide projections is elastically deformable to facilitate positioning of said projections within said guide grooves.
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132. A drive mechanism for a zoom lens which is adapted to be used in a camera having an optical axis, said drive mechanism comprising:
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(a) a stationary barrel having a plurality of helicoidal threads attached to an internal surface of said barrel; (b) a cam ring having an outer surface with a plurality of helicoidal threads adapted to be engaged by said stationary barrel helicoidal threads; (c) a cam ring gear which extends in the direction of said cam ring threads; and (d) a cam ring driving mechanism having a driving gear which is adapted to engage said cam ring gear - View Dependent Claims (133, 134, 135, 136, 137)
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- 138. A zoom lens barrel comprising two rotatable cylindrical members having respective male and female helicoidal threads which are adapted to engage each other upon rotation of one of said cylindrical members, wherein one of said members has a cutaway portion for separating engagement of said male and female threads at a predetermined angular position of said members, wherein said one member has threads which are adjacent to said cutaway portion, said adjacent threads having end faces with tapered surfaces which gradually decrease the width of the adjacent threads and increase the width of a groove defined between said adjacent threads, in a direction towards said cutaway portion.
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142. A zoom lens comprising:
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(a) a stationary barrel which is adapted to be used with a camera having an optical axis; (b) a cam ring supported by said stationary barrel for movement along said optical axis; (c) a lens guide ring adapted to move along said optical axis; (d) at least two movable lens groups which are adapted to be movably supported by said cam ring and said lens guide ring so as to move, along said optical axis, to thereby comprise means for changing a focal length of said zoom lens; and (e) a flange back adjusting mechanism comprising an outer ring adapted to be attached to said stationary barrel, between said barrel and said cam ring, said outer ring being rotatably adjustable, said mechanism further comprising flange back adjusting means for threadably engaging said outer ring to adjustably rotate said outer ring. - View Dependent Claims (143, 144, 145, 146, 147, 148, 149, 150)
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- 151. A method for adjusting the position of a group of lenses with respect to a film plane in a camera having an optical axis and a zoom lens with a stationary barrel, movable lens groups which are movably positioned along said optical axis by a rotatable cam ring and a non-rotatable lens guide ring, both of said rings being movable along said optical axis, and male and female helicoidal rings positioned concentrically between said stationary barrel, and said cam ring, said cam ring including a ring flange on the outside of said cam ring, said method comprising rotating an adjusting gear which is engaged with a gear sector on said ring flange by rotating a tool which engages at least a portion of said adjusting gear, so as to rotate said cam ring.
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153. A zoom lens barrel adapted to be attached to a camera having an optical axis, said zoom lens barrel comprising a stationary barrel and a rotatable cam ring which is adapted to be driven by means for driving said cam ring, said driving means being stationary along the optical axis of said camera, said cam ring being movably supported by said stationary barrel for movement along said optical axis, during zooming operation of front and rear movable lens groups, in association with rotation of said cam ring, said cam ring including at least two cam grooves which are adapted to receive said front and said rear movable lens groups, wherein the axial positions of said movable lens groups are at least partially determined by said cam grooves, said driving means comprising a motor for driving said cam ring, said motor driving a gear which is adapted to engage an outer peripheral surface of said cam ring.
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154. A zoom lens apparatus adapted for use with a camera having an optical axis, said zoom lens apparatus including a movable front lens group and a movable rear lens group, said lens groups being housed within a stationary barrel, said lens groups being moved along said optical axis, during zooming movement of said movable lens groups, in response to linear and rotational movement of a ring assembly along said optical axis, said linear movement of said ring assembly being effected by rotational movement of said ring assembly, said ring assembly being driven by driving means which is stationary along said optical axis, said driving means comprising a motor for driving said ring assembly, said zoom lens apparatus being used in combination with said motor, said motor driving a gear which is adapted to engage an outer peripheral surface of a ring in said ring assembly.
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155. A zoom lens adapted for use with a camera having an optical axis, said zoom lens comprising a cam ring movable along said optical axis, at least one lens movable along said optical axis in association with movement of said cam ring along the optical axis so as to vary a focal length of said zoom lens during zooming operation of said zoom lens, means for driving said cam ring, said driving means being stationary along said optical axis, and means for movably holding said at least one lens, wherein said cam ring comprises means for moving said at least one lens along said optical axis over a distance greater than the distance over which said cam ring moves along the optical axis, wherein said driving means comprises a motor for driving said cam ring, said zoom lens being used in combination with said motor, said motor driving a gear which is adapted to engage an outer peripheral surface of said cam ring.
Specification