Asahi Kogaku Kogyo Kabushiki Kaisha

Pentax Corporation

Asahi Kogaku Kabushiki Kaisha

Tomoaki Kobayashi

Shinsuke Kohmoto

Hiroshi Nomura

Makoto Iikawa

Takayuki Ito

Osamu Sato

Keisuke Haraguchi

Takuji Hamasaki

Hisashi Tatamiya

Yukio Takaoka

Satoru Horita

Takeo Kobayashi

Takahiro Kobayashi

Masashi Takahashi

Hiroaki Suzuki

Thogi Kondo

A lens body tube includes a main tube, at least one lens configured movable along the optical axis direction of the lens body tube in the main tube, a first ring configured to be rotated for a zooming operation, the first ring being disposed around the outer circumference of the main tube, a second ring configured to be rotated for a focusing operation, the second ring being disposed around the outer circumference of the main tube, a third ring configured to be rotated by the first ring, the third ring being disposed inside the main tube, a fourth ring configured to be translated along the optical axis direction by rotation of the third ring, the fourth ring being disposed inside the main tube, a fifth ring configured to be rotated by the second ring, and at least one lens frame, of the at least one lens, supported by the fifth ring. The fifth ring is screwed together with the fourth ring.

Lens body tube

A lens body tube configured to support at least one lens inside an inner tube such that the at least one lens can be translated along the optical axis direction of the lens body tube includes a cam ring configured to be rotatably supported around the outer circumferential surface of the inner tube, the at least one lens being configured to be translated along the optical axis direction accompanied by the rotation of the cam ring, a plurality of cams provided on the inner circumferential surface of the cam ring, and a plurality of cam followers provided on a lens frame supporting each of the at least one lens. Each of the plurality of cam followers is engaged with a corresponding one of the plurality of cams. The plurality of cams includes at least two protruded cams. The at least two protruded cams are connected with a part of each other.

A lens body tube configured to support at least one lens inside an inner tube such that the at least one lens can be translated along the optical axis direction of the lens body tube includes a cam ring configured to be rotatably supported around the outer circumferential surface of the inner tube, the at least one lens being configured to be translated along the optical axis direction accompanied by the rotation of the cam ring, a plurality of cams provided on the inner circumferential surface of the cam ring, a plurality of cam followers provided on a lens frame supporting each of the at least one lens, each of the plurality of cam followers being engaged with a corresponding one of the plurality of cams through an opening provided on the inner tube, and a plurality of first protrusions, each of which is formed integrally with a corresponding one of the plurality of cams, and has contact with the outer circumferential surface of the inner tube.

A lens barrel includes a linear guide ring; a linearly movable ring which is provided inside the linear guide ring and has a cam on an outer circumferential surface; and a hand-operated rotating ring, provided outside the linear guide ring, which is capable of rotating in a circumferential direction and is incapable of rotating in an optical axis direction, with respect to the linear guide ring and which has a first penetrate groove. The linear guide ring, the linearly movable ring and the hand-operated rotating ring are provided concentrically to each other. A rotation motion of the hand-operated rotating ring with respect to the linear guide ring causes the linearly movable ring to move linearly along the optical axis direction, via the linear guide ring. The linear guide ring has a second penetrate groove penetrated in a radial direction. A projection member, which is to be engaged with the cam provided on the linear movable ring, via the second penetrate groove of the linear guide ring, is inserted from an outside of the hand-operated rotating ring.

Lens barrel

A lens barrel includes a cam ring which is rotatable about an optical axis, and at least two linearly movable members provided inside or outside the cam ring, the linearly movable members being linearly guided in an optical axis direction. A plurality of cams are formed on an inner peripheral surface or an outer peripheral surface of the cam ring. Furthermore, at least two adjacent cams overlap at least partly as viewed in the optical axis direction, one of the two adjacent cams being a cam projection and the other of the two adjacent cams being a cam groove, and a follower recess portion and a follower projection portion, which are relatively movably fitted into the cam projection and the cam groove, respectively, are respectively formed on the linearly movable members.

Lens barrel and cam ring

A bearing structure comprises a rotational shaft and a bearing member. The rotational shaft has a pair of flanges, and a small diameter portion provided between the flanges. The flanges have first tapered surfaces. The first tapered surfaces taper down to the diameter of the small diameter portion as the first tapered surfaces approach the small diameter portion. The bearing member has a support groove to support the small diameter portion, and second tapered surfaces formed between the support groove and restraining surfaces connected by the support groove. The small diameter portion is fit in the support groove while the first tapered surfaces are engaged with the second tapered surfaces. A flank is formed on at least one part of the flanges that face each other and at substantially the same circumferential position on the flanges, to form a gap with one of the second tapered surfaces.

Bearing structure

A camera body includes a plurality of body contact members which can contact and electrically connect to a plurality of lens contact members of a photographic lens when the photographic lens is attached to the camera body. The camera body also includes a communication device which can receive fixed information via a first predetermined body contact member group if a photographic lens that allows the reception of fixed information is attached to the camera body, and which can transmit arbitrary information via a second predetermined body contact member group if a photographic lens that allows the transmission of arbitrary information is attached to the camera body. The camera body further includes an identifying device that determines whether or not an attached photographic lens allows the transmission of arbitrary information via first and second body contact members not belonging to the first predetermined body contact member group.

Photographic lens recognition system for a camera body

A camera body in which, when a photographic lens is attached to the camera body, data exchange is carried out by communicating with the photographic lens via a plurality of contact pins electrically connected to each other. The camera body includes: a reset pin as one of the contact pins which outputs a reset signal and a reset release signal; an identifying pin as another of the contact pins for identifying an attached photographic lens; and an identifying device which identifies an attached photographic lens according to the change of electric potential of the identifying pin upon the output of the reset release signal to the reset pin.

Setting communication system in accordance with type of lens attached to body

A lens barrel has an immovable cylindrical member adapted to be detachably attached to a camera body, and a lens holder for holding a group of focusing lenses. The holder is disposed in the member so as to be movable along an optical axis of the focusing lenses for a focusing adjustment. A manual-focusing ring, rotatably mounted on the member, is manually movable along the optical axis between an auto-focusing (AF) position and a manual-focusing (MF) position, and has a plurality of recesses circumferentially arranged and formed on an inner wall surface thereof. A drive mechanism, provided between the member and the holder to convert a rotation into a translation of the holder along the optical axis, has at least a pin which is subjected to the rotation. The pin is engaged in one of the recesses of the ring when the ring is at the MF position, such that a rotation of the ring is transmitted to the drive mechanism. The pin is disengaged from the one of the recesses of the ring when the ring is at the AF position.

A zoom lens assembly includes a stationary lens barrel and a rotatable cam ring which is supported on the stationary lens barrel for movement in the direction of the optical axis while being rotated, and which includes at least two cam grooves. The zoom lens include first and third lens groups which are both moveable by one of the two cam grooves in the direction of the optical axis. A second lens group movable, by a second of the two cam grooves in the direction of the optical axis is also provided, as well as a focusing mechanism, for moving the second lens group to a position which is determined by focal length data derived from actual positions of the first, second, and third lens groups and object distance data detected by an object distance measuring device. A method of controlling focusing of the zoom lens includes correcting an amount of deviation from focus caused by a zooming operation, by moving the focusing lens group. The method includes setting a reference object distance, at which no deviation from focus occurs during zooming of the zoom lens, at a finite object distance, such that the amount of movement of the focusing lens group necessary to effect focusing is determined based upon a reference position corresponding to a position of the focusing lens group at the reference object distance, in accordance with focal length data and object distance data.

Zoom lens barrel

A zoom lens assembly includes a stationary lens barrel and a rotatable cam ring which is supported on the stationary lens barrel for movement in the direction of the optical axis while being rotated, and which includes at least two cam grooves. The zoom lens include first and third lens groups which are both movable by one of the two cam grooves in the direction of the optical axis. A second lens group movable, by a second of the two cam grooves in the direction of the optical axis is also provided, as well as a focusing mechanism, for moving the second lens group to a position which is determined by focal length data derived from actual positions of the first, second, and third lens groups and object distance data detected by an object distance measuring device. A method of controlling focusing of the zoom lens includes correcting an amount of deviation from focus caused by a zooming operation, by moving the focusing lens group. The method includes setting a reference object distance, at which no deviation from focus occurs during zooming of the zoom lens, at a finite object distance, such that the amount of movement of the focusing lens group necessary to effect focusing is determined based upon a reference position corresponding to a position of the focusing lens group at the reference object distance, in accordance with focal length data and object distance data.

A barrier mechanism for a zoom lens assembly which includes a stationary lens barrel and a rotatable cam ring which is supported on the stationary lens barrel for movement in the direction of the optical axis while being rotated, and which includes at least two cam grooves. The barrier mechanism of the lens barrel includes a pair of barrier plate assemblies which are adapted to open and close an opening of the lens barrel, wherein each of the pair of barrier plate assemblies includes a pair of plate elements which are symmetrically arranged with respect to a center of the opening. In the closed position, the barrier plates are arranged side by side.

A diaphragm mechanism in a zoom lens barrel includes a front movable lens group which is moved together with the diaphragm mechanism, a rear movable lens group located behind the front movable lens group, a diaphragm driving member which can engage with a diaphragm driving member provided on an associated camera body, and an intermediate drive transmitting member which transmits movement of the diaphragm driving member of the lens barrel to the diaphragm mechanism which is provided with a rear lens frame holding the rear movable lens group. The intermediate drive transmitting member is supported on the rear lens frame.

Diaphragm mechanism of zoom lens barrel

A cover unit for lens unit having a lens barrel, which has a cylindrical support member to be coupled to an end of the lens barrel, at least one engaging pin member is provided at a predetermined position on the outer circumferential surface thereof. Further, the cover unit has a cylindrical hood member capable of being superposed on the lens barrel, at least one cam groove to slidably receive the at-least-one engaging pin member therein being formed on the inner circumferential surface of the hood member, wherein by means of the engagement of the at-least-one engaging pin member with the at-least-one cam groove, the hood member moves in its axial direction relative to the support member upon rotation of the hood member relative to the support member. Lens barriers are supported by the support member for covering the end of the lens barrel, the lens barrier means being openable. The lens barriers are driven in accordance with the movement of the hood member.

Growing community of inventors

Saitama, Japan

Tomoaki Kobayashi