Lens barrel

A lens barrel is provided and includes: a lens barrel main body; and a connecting member attached to the barrel main body and connected to a camera. The connecting member includes an optical filter unit, divided at a position of the optical filter unit and is constituted by a barrel side member and a camera side member.

FIELD OF THE INVENTION

The present invention relates to a lens barrel, particularly relates to a lens barrel mounted to a monitoring camera.

BACKGROUND OF THE INVENTION

A lens apparatus of a monitoring camera is attached to the monitoring camera by fastening a mount ring provided at a rear end portion in an optical axis direction of a lens barrel main body to a main body of the monitoring camera (refer to JP-A-2003-255210). Various shapes of the mount rings of the lens apparatus need to be prepared in accordance with a shape, a position of CCD on a side of the camera, a heat radiating characteristic of CCD and the like. Therefore, in a background art, a number of the mount rings having different shapes are prepared, selected in accordance with a specification of a camera and mounted thereto.

Meanwhile, a mount ring of a lens apparatus needs high working accuracy at a portion thereof connected to a lens barrel main body and therefore, there poses a problem that a die in molding the mount ring by a resin is expensive, and fabrication cost is high. Therefore, there poses a problem that cost of a lens barrel is significantly increased by preparing a number of kinds of the mount rings.

A monitoring camera for taking an image day and night provides a picture image by utilizing an infrared ray in taking an image at night, and an infrared ray needs to be cut in taking an image in daytime. Therefore, a lens apparatus of the monitoring camera for taking an image day and night is provided with a filter switching apparatus for arranging an IR cut filter on an optical path, or escaping the IR cut filter from the optical path. Further, the monitoring camera can take an image day and night by arranging the IR cut filter on the optical path in taking an image in daytime and escaping the IR cut filter from the optical path at night by using the filter switching apparatus.

The IR cut filter and the filter switching apparatus are normally attached to a frame or a base seat to be unitized, which is integrated to a lens barrel. For example, according to a lens barrel described in JP-A-2004-347624, an optical filter is slidably supported by a guide frame, a unit of a filter switching apparatus is attached to a base seat, and these units are integrated to between a mount and a fixed cylinder.

However, the lens barrel of JP-A-2004-347624 needs a guide frame or a base seat and therefore, a problem that the apparatus is large-sized is posed. Further, the lens barrel of JP-A-2004-347624 poses a problem that a back focus (a distance from an apex of a final refracting face of a lens to a focusing face) is prolonged by an amount of a thickness of the guide frame or the base seat to deteriorate optical properties.

JP-A-2002-189238 and JP-A-2003-348398 describe a lens barrel in which an optical filter and a filter switching apparatus are integrated to a diaphragm apparatus. According to the lens barrel, the lens barrel can be downsized in an optical axis direction by attaching the optical filter and the filter switching apparatus to a board of the diaphragm apparatus.

However, since the lens barrel of JP-A-2002-189238 and JP-A-2003-348398 is provided with the optical filter and the filter switching apparatus at the diaphragm apparatus, there poses a problem that a thickness of a total of the diaphragm apparatus is increased, movable ranges of optical lenses on front and rear sides of the diaphragm apparatus are restricted, and optical properties are deteriorated.

Further, the lens barrel of JP-A-2002-189238 and JP-A-2003-348398 also poses a problem that when the optical filter is not needed, the total of the diaphragm apparatus needs to be interchanged, and cost is increased.

A lens barrel is connected to a camera by way of a connecting member referred to as lens mount. Normally, the lens barrel and the connecting member are fixed by a screw or the like. The connecting member needs a sufficient mechanical strength for preventing the connecting member from being destructed by unpreparedly strong force or impact in mounting to the camera. Therefore, with regard to the connecting member of the lens barrel, in a background art, there have been proposed various connecting members for increasing the mechanical strength.

For example, JP-A-2000-29116 describes a connecting member in which a portion thereof screwed to be fixed to a lens barrel and a bayonet claw engaged with a camera are reinforced by metal members. According to the connecting member, strengths of a portion screwed to be fixed thereto and the bayonet claw are increased and therefore, the connecting member can be fixed to the lens barrel by a solid fastening force, further, a force of engaging the connecting member of the camera can be increased. Thereby, the connecting member can be prevented from being destructed by an unpreparedly strong force or impact in mounting to the camera.

However, JP-A-2000-29116 poses a problem that warp is brought about at a barrel main body of the lens barrel by fixing the connecting member to the lens barrel by a strong fastening force. Further, by bringing about warp at the barrel main body, there is brought about a drawback that a resistance of sliding an operating ring of a focus ring, a zoom ring or the like and the barrel main body is increased and operability is deteriorated.

Further, JP-A-2000-29116 poses a problem that when the connecting member is screwed to be fixed to the lens barrel by the strong fastening force, a thread ridge of a female screw on a side of the barrel main body is destructed, and the barrel main body per se needs to be interchanged.

SUMMARY OF THE INVENTION

An object of an illustrative, non-limiting embodiment of the invention is to provide a lens barrel capable of being mounted to a number of kinds of cameras having different specifications and capable of reducing fabrication cost.

Another object of an illustrative, non-limiting embodiment of the invention is to provide a lens barrel capable for promoting optical properties and capable of being downsized.

Still another object of an illustrative, non-limiting embodiment of the invention is to provide a lens barrel capable of firmly fixing a connecting member to a barrel main body of a lens barrel and capable of preventing the barrel main body from being warped or damaged.

The following means can achieve the above-described objects.(1) A lens barrel is characterized in including: a barrel main body; and a connecting member attached to the barrel main body and connected to a camera, wherein the connecting member is constituted by being divided into a portion on a side of the barrel main body (a first portion) and a portion on a side of the camera (a second portion).

According to an embodiment described in (1), the connecting member is divided into the side of the barrel main body which needs high working accuracy and the side of the camera which does not need high working accuracy but needs a number of kinds of shapes and therefore, cost of a total of the connecting member can be reduced. That is, according to an embodiment of (1), cost of the total of the connecting member can be reduced by commonly using the portion on the side of the barrel main body which needs high working accuracy for a plurality of cameras and preparing a number of kinds of only the portion on the side of the camera which does not need high working accuracy in accordance with a specification of the camera.(2) The lens barrel according to (1) is characterized in that an optical filter is arranged between the portion on the side of the barrel main body and the portion on the side of the camera.

According to an embodiment of (2), the optical filter is arranged between the portion on the side of the barrel main body and the portion on the side of the camera and therefore, the optical filter can easily be integrated to inside of the connecting member.(3) The lens barrel according to (2) is characterized in that the connecting member is formed with a recess portion for containing (housing) the optical filter at least one dividing face of the portion on the side of the barrel main body and the portion on the side of the lens. (That is, at least one portion of the portion on the side of the barrel main body and the portion on the side of the camera has a recess portion on a face opposite to the other portion.)

According to an embodiment of (3), the recess portion for containing the optical filter is formed at the dividing face and therefore, when the portion on the side of the barrel main body and the portion on the side of the lens are integrated, inside of the connecting member is formed with a hollow portion constituting a space of containing the optical filter.(4) The lens barrel according to any one of (1) to (3) is characterized in that the portion on the side of the barrel main body and the portion on the side of the camera are fixed by screwing or a snap in mechanism.(5) A lens barrel is characterized in including: an optical filter; and filter inserting and drawing means capable of inserting or drawing the optical filter on an optical path, wherein the optical filter and the filter inserting and drawing means are integrated to a connecting member attached to a barrel main body and connected to a camera.

According to an embodiment of (5), the optical filter and the filter inserting and drawing means are integrated to the connecting member and therefore, a frame for holding the optical filter and a base seat of the filter inserting and drawing means are dispensed with. Therefore, the lens barrel can be downsized.

Further, according to an embodiment of (5), by integrating the optical filter and the filter inserting and drawing means to the connecting member, a movable range of a lens is not restricted by the optical filter and the like. Therefore, optical properties can be promoted.(6) The lens barrel according to (5) is characterized in that the connecting member is divided at a position of the optical filter and is constituted by a member on a side of the barrel main body and a member on a side of the camera.

According to an embodiment of (6), the optical filter can easily be included in the connecting member.(7) A lens barrel is characterized in including: a barrel main body and; a connecting member fixed to the barrel main body and connected to a camera, wherein one of the barrel main body and the connecting member is provided with an elastically deformable arm having a claw at a front end portion thereof, and the other of the barrel main body and the connecting member is provided with an engaging portion engaged with the claw of the arm. That is, an embodiment of (7) is characterized in connecting the barrel main body and the connecting member by using a snap in mechanism. Thereby, according to an embodiment of (7), the barrel main body and the connecting member are connected always by a pertinent force by an elastic force of the arm and therefore, the barrel main body can be prevented from being warped in connecting the barrel main body and the connecting member. Thereby, a feeling of operating an operating ring can be promoted.

Further, according to an embodiment of (7), the barrel main body and the connecting member are connected by using the snap in mechanism therefor, a fixing member of a screw or the like is dispensed with, and a tool of a screwdriver or the like is dispensed with. Therefore, according to an embodiment of (7), the barrel main body and the connecting member can be connected easily and at low cost.(8) The lens barrel according to (7) is characterized in that the arm is formed in a peripheral direction centering on an optical axis. According to an embodiment of (8), by rotating the connecting member in the peripheral direction relative to the barrel main body, a claw of the arm is engaged with the engaging portion, and the connecting member and the barrel main body are connected. In this way, when the connecting member is rotated in the peripheral direction and connected to the barrel main body, the connecting member and the barrel main body can be connected in a state of being positioned in a direction of an optical axis. Therefore, optical properties of the lens barrel can be promoted.

According to an exemplary embodiment of the invention, the connecting member is constructed by a constitution of being divided into the side of the barrel main body which needs high working accuracy and the side of the camera which does not need high working accuracy but needs a number of kinds of shapes and therefore, the portion on the side of the barrel main body having high cost can commonly be used for a plurality of cameras. Thereby, cost of a total of the lens barrel can be reduced even when used in a plurality of cameras having different specifications.

Since the optical filter and the filter inserting and drawing means are integrated to the connecting member, the lens barrel can be downsized, and optical properties can be promoted by widening a movable range of a lens.

According to another embodiment of the invention, the barrel main body of the lens barrel and the connecting member are connected by using the snap in mechanism and therefore, the barrel main body and the connecting member can be connected always by a pertinent force and the barrel main body can be prevented from being warped in connecting the barrel main body and the connecting member. Further, the barrel main body and the connecting member are connected by using the snap in mechanism and therefore, a fixing member of a screw or the like or a tool for fixing is dispensed with, and the barrel main body and the connecting member can be connected easily and at low cost.

DETAILED DESCRIPTION OF THE INVENTION

An explanation will be given of exemplary embodiments of a lens barrel according to the invention in reference to the attaching drawings as follows.

FIRST EMBODIMENT

FIG. 1is a side sectional view showing a constitution of a lens barrel10mainly mounted to a monitoring camera. The lens barrel10shown in the drawing is mainly constituted by a barrel main body12(also referred to as fixed cylinder) substantially in a cylindrical shape, a connecting member14(also referred to as mount) attached to a base end portion of the barrel main body12and connected to a camera18, and a diaphragm apparatus16inserted into the barrel main body12from a side of a peripheral face thereof to be mounted thereto.

The barrel main body12comprises a large diameter portion12A on a front end side and a small diameter portion12B on a base end side, and the large diameter portion12A and the small diameter portion12B are integrally molded by a resin. A focus ring20is pivotably supported by an outer peripheral face of the large diameter portion12A, and a zoom ring30is pivotably supported by an outer peripheral face of the small diameter portion12B.

Inside of the large diameter portion12A of the barrel main body12is arranged with a focus lens (group)22held by a lens frame24on an optical axis P. An outer peripheral face of the lens frame24is projected with an engaging portion24C, and the engaging portion24C is engaged with a straight advancing groove12C formed in a direction of the optical axis P. Thereby, the lens frame24and the focus lens (group)22are movably supported in a direction of the optical axis P.

The engaging portion24C of the lens frame24is projected with a cam pin26and the cam pin26is engaged with a cam groove20C formed on an inner peripheral face of the focus ring20. Therefore, when the focus ring20is operated to pivot, a position of intersecting the cam groove20C and the straight advancing groove12C is displaced in the direction of the optical axis P, and the lens frame24and the focus lens (group)22are moved in the direction of the optical axis P in accordance with displacement of the intersecting position. Thereby, the focus lens (group)22is moved in the direction of the optical axis P to adjust to focus. Further, it is preferable to provide a plurality of engaging portions each comprising the engaging portion24C of the lens frame24, the cam pin26, the cam groove20C of the focus ring20, and the straight advancing groove12C of the barrel main body12in order to stably move the lens frame24, normally, the engaging portions are provided at three locations constituted by equally dividing a circumference by three.

Further, the focus ring20is formed with a screw hole20A penetrated from the outer peripheral face to the inner peripheral face, and a knob28is screwed to be attached to the screw hole20A. An operator can also operate to pivot the focus ring20by using the knob28. Further, the focus ring20can be fixed at a desired focus adjusting position by screwing the knob28to press a front end thereof to the outer peripheral face of the large diameter portion12A of the barrel main body12.

Inside of the small diameter portion12B of the barrel main body12is arranged with a zoom lens (group)32held by a lens frame34on the optical axis P. An outer peripheral face of the lens frame34is projected with an engaging portion34D, and the engaging portion34D is engaged with a straight advancing groove12D formed in the direction of the optical axis P. Thereby, the lens frame34and the zoom lens (group)32are movably supported in the direction of the optical axis P.

The engaging portion34D of the lens frame34is projected with a cam pin36, and the cam pin36is engaged with a cam groove30D formed at an inner peripheral face of the zoom ring30. Therefore, when the zoom ring30is operated to pivot, a position of intersecting the cam groove30D and the straight advancing groove12D is displaced in the direction of the optical axis P, and the lens frame34is moved in the direction of the optical axis P in accordance with displacement of the intersecting position. Thereby, the zoom lens32is moved in the direction of the optical axis P and a focal length (zoom picture angle) is adjusted. Further, it is preferable to provide a plurality of engaging portions each comprising the engaging portion34D of the lens frame34, the cam pin36, the cam groove30D of the zoom lens30, and the straight advancing groove12D of the barrel main body12in order to stably move the lens frame34, normally, the engaging portions are provided at three locations constituted by equally dividing a circumference by three.

Further, the zoom ring30is formed with a screw hole30A penetrated from the outer peripheral face to the inner peripheral face, and a knob38is screwed to be attached to the screw hole30A. The operator can also operate to pivot the focus ring30by using the knob38. Further, the zoom ring30can be fixed at a desired focal length adjusting position by screwing the knob38to press a front end thereof to an outer peripheral face of the small diameter portion12B of the barrel main body12.

As shown byFIG. 2, the diaphragm apparatus16includes a casing60in a plate-like shape, and the casing60is inserted to be mounted to the barrel main body12. Specifically, a boundary portion of the large diameter portion12A and the small diameter portion12B of the barrel main body12is formed with an opening portion12E in a slit-like shape in a circumferential direction, and the plate-like casing60is inserted to be mounted to the opening portion12E in the slit-like shape in a direction orthogonal to the optical axis P. The casing60and the barrel main body12are connected by a snap in structure, not illustrated. That is, the casing60is provided with an elastically deformable arm, and a front end of the arm is formed with a claw for engaging. Further, by fitting the claw for engaging to a groove of the barrel main body12, the casing60of the diaphragm apparatus16is mounted to the barrel main body12. Further, a method of connecting the diaphragm apparatus16and the barrel main body12is not limited to the snap in structure but other connecting method of screwing by screw or the like can also be selected.

The casing60is formed with an opening60A in a circular shape, and the opening60A is arranged on the optical axis P when the casing60is mounted to the barrel main body12. Further, inside of the casing60is provided with two sheets of diaphragm blades (not illustrated), one of the diaphragm blades is arranged on an upper side of the opening60A, and the other of the diaphragm blades is arranged on a lower side of the opening60B. The respective diaphragm blades are supported slidably in an up and down direction, and the respective diaphragm blades are moved in the up and down direction by driving a drive portion (iris meter or the like)62attached to a lower end of the casing60. Further, the opening60A is closed by two sheets of the diaphragm blades by moving the diaphragm blade arranged on the upper side of the opening60A to the lower side and moving the diaphragm blade arranged on the lower side of the opening60A to the upper side to bring about a state in which object light does not pass therethrough. Further, two sheets of the diaphragm blades are escaped from the opening60A by moving the diaphragm blade on the upper side to the upper side and moving the diaphragm blade on the lower side to the lower side by driving the drive portion62to bring about the state in which the object light can pass through a total of the opening60A. Further, a constitution of the diaphragm apparatus16is not limited to the above-described but an iris diaphragm mechanism or the like may be used.

As shown byFIG. 2, the diaphragm apparatus16is provided with pivoting restricting portions64,64, and an operating ring of the focus ring20, the zoom ring30or the like is restricted from being pivoted by the pivoting restricting portions64,64. The pivoting restricting portions64,64are formed to be projected at a portion of connecting the casing60and the drive portion62of the diaphragm apparatus16and to both outer sides thereof. Further, each pivoting restricting portion64is constituted by a restricting portion64B for focusing at a front end side and a restricting portion64A for zooming on a base end side.

The diaphragm apparatus16constituted as described above is inserted to be mounted to the opening portion14E of the barrel main body12after attaching the focus ring20and the zoom ring30to the barrel main body12. Thereby, the pivoting restricting portion64of the diaphragm apparatus16is arranged at a predetermined position and restriction of pivoting the focus ring20and restriction of pivoting the zoom ring30are carried out by the pivoting restricting portion64. That is, the focus ring20is restricted from being pivoted by the restricting portion64B for focusing and the zoom ring30for zooming is restricted from being pivoted by the restricting portion64A. Further, the pivoting restricting portions64,64serve also as means for positioning the diaphragm apparatus16relative to the barrel main body12when the diaphragm apparatus16is inserted to be mounted to the barrel main body12.

An explanation will be given of restriction of pivoting the focus ring20in reference toFIG. 2andFIGS. 3A through 3Cas follows.FIGS. 3A through 3Cshow a section taken along a line3-3ofFIG. 1,FIG. 3Ashows a state in which there is not pivoting operation, andFIG. 3B,FIG. 3Cshow states of carrying out pivoting operation in directions respectively inverse to each other and pivoting operation is restricted.

As shown byFIG. 2, a portion of an end face on a base end side of the focus ring20(specifically, substantially ⅔ on an upper side) is projected, and the projected portion is formed with stepped difference portions20D,20D at both end portions of the projected portion. The stepped difference portions20D,20D are projected from a base end of the large diameter portion12A of the barrel main body12to be arranged on the small diameter portion12B when the focus ring20is mounted to the barrel main body12. Further, as shown byFIG. 3A, the stepped difference portions20D,20D include inclined faces20E,20E cut skewedly and the inclined faces20E are constituted to be brought into face contact with the restricting portions64B for focus when the focus ring20is pivoted as shown byFIG. 3BorFIG. 3C.

When the focus ring20constituted as described above is operated to pivot from the state shown inFIG. 3Ain the counterclockwise direction, as shown byFIG. 3B, the inclined face24E of the stepped difference portion20D is brought into contact with the restricting portion64B for focusing to restrict pivoting operation of the focus ring20. Further, when the focus ring20is operated to pivot in the clockwise direction from the state shown inFIG. 3A, as shown byFIG. 3C, the inclined face20E of the stepped difference portion20D on an opposed side is brought into contact with the restricting portion64B for focusing to restrict pivoting operation of the focus ring20. Thereby, the focus ring20can be set to an accurate operation range and focusing operation can accurately be carried out.

Next, pivoting restriction of the zoom ring30will be explained in reference toFIG. 2andFIGS. 4A through 4C.FIGS. 4A through 4Cshow a section taken along a line4-4ofFIG. 1,FIG. 4Ashows a state in which there is not pivoting operation, andFIG. 4B,FIG. 4Cshow states in which pivoting operation is carried out in directions respectively inverse to each other and pivoting operation is restricted.

As shown byFIG. 4A, the zoom ring30is provided with a projected portion26projected from an outer peripheral face. The projected portion66comprises, for example, a resin and is integrally formed with the zoom ring30. Further, as shown byFIG. 4A, it is preferable to form the projected portion66by a range smaller than that in the focus ring20. Further, the projected portions66are formed with contact faces66A,66A brought into face contact with the restricting portions64A,64A for zooming when the zoom ring30is operated to pivot as shown byFIG. 4BorFIG. 4C.

When the zoom ring30constituted as described above is operated to pivot in the counterclockwise direction from the state shown inFIG. 4A, as shown byFIG. 4B, the projected portion66is brought into contact with the restricting portion64A for zooming to restrict pivoting operation of the zoom ring30. Further, when the zoom ring30is operated to pivot in the clockwise direction from the state shown inFIG. 4A, as shown byFIG. 4C, the projected portion66is brought into contact with the restricting portion64A for zooming to restrict pivoting operation of the zoom ring30. Thereby, the zoom ring30can be set to an accurate operation range, and zoom operation can accurately be carried out.

On the other hand, the connecting member14shown inFIG. 1is a member for connecting the barrel main body12and the camera18and is attached to a base end of the small diameter portion12B of the barrel main body12. An optical filter unit40, mentioned later, is included at inside of the connecting member14, and the connecting member14is constructed by a constitution of being divided in two at a position of an IR cut filter46(in correspondence with an optical filter) of the optical filter unit40. That is, as shown byFIG. 5, the connecting member14is constituted by a barrel side member14A on a side of the barrel main body12of a filter attaching plate42of the IR cut filter46(left depth side ofFIG. 5), and a camera side member14B on a side of the camera18of the filter attaching plate42(right front side ofFIG. 5), and the connecting member14is constituted by connecting the barrel side member14A and the camera side member14B. Further, although a method of connecting the barrel side member14A and the camera side member14B is not particularly limited, for example, a connecting method utilizing a screw, or a fixing method using a snap in structure is adopted.

The optical filter unit40mainly comprises the filter attaching plate42and an actuator44for inserting and drawing the filter attaching plate42relative to the optical axis P, and the filter attaching plate42is arranged with the IR (infrared ray) cut filter46and a dummy filter48aligned in an up and down direction. Further, an ND filter or a visible light cut filter may be arranged in place of the IR cut filter46and the dummy filter48.

The filter attaching plate42is formed with a plurality of guide holes42A prolonged in the up and down direction, the respective guide holes42A are inserted with a plurality of guide pins56projected from the barrel side member14A of the connecting member14to be guided thereby. Thereby, the filter attaching plate42is supported by the barrel side member14A slidably in the up and down direction.

Further, an upper portion of the filter attaching plate42is formed with a long hole42B in a lateral direction, and the long hole42B is inserted with an arm44C of the actuator44to be guided thereby.

A main body of the actuator44is mounted to an attaching portion58at an upper portion of the barrel side member14A to be held thereby. Although a method of mounting the actuator44to the barrel side member14A is not particularly limited, fixing by a screw, or a snap in structure is used therefor.

Further, the actuator44includes a rotating shaft44A, the rotating shaft44A is attached with a circular disk44B, and the arm44C is erected from an outer peripheral portion of the circular disk44B. Further, the arm44C is inserted into the long hole48B of the filter attaching plate42to be engaged therewith.

According to the optical filter unit40constituted as described above, when the rotating shaft44A is rotated by driving the actuator44, the circular disk44B is rotated and the arm44C is moved around the rotating shaft44A, and the filter attaching plate42is moved in the up and down direction in accordance with movement of the arm44C. Thereby, the optical filter arranged on the optical axis P can be switched to the IR cut filter46and the dummy filter48. Therefore, by arranging the IR cut filter46on the optical axis P when an image is taken in daytime and arranging the dummy filter48on the optical axis P when an image is taken at night, the image can be taken both in daytime and at night.

As shown byFIG. 1, the barrel side member14A of the connecting member14is fixed to the base end portion of the small diameter portion12B of the barrel main body12. Although a method of fixing the barrel side member14A and the small diameter portion12B is not particularly limited, for example, the barrel side member14A and the small diameter portion12B are connected by a snap in structure. Further, the barrel side member14A needs to be positioned relative to focus lens22and the zoom lens32and therefore, high working accuracy is needed therefor.

Further, as shown byFIG. 5, the barrel side member14A is formed with a recess portion54for containing the filter attaching plate42at a face thereof connected to the camera side member14B (dividing face). The recess portion54is provided with a space for sliding the filter attaching plate42in the up and down direction, and a side face of the recess portion54is projected to be formed with a plurality of projected portions56in a circular arc shape for guiding the filter attaching plate42at constant intervals. Therefore, the filter attaching plate42can be slid in the up and down direction in a state of being contained in the recess portion54.

On the other hand, the camera side member14B includes a stepped difference14D for holding LPF (low path filter)50(refer toFIG. 1) on the optical axis P, in a state of arranging LPF50to the stepped difference14D and arranging a rubber member52in a plate-like shape, a front end portion of the camera18is inserted to be mounted thereby. The camera18mounted in the embodiment is the camera18referred to as a built-in type in which CCD18A and an attaching board thereof are exposed.

Whereas the camera side member14B mounted with the camera18does not need working accuracy as high as that of the barrel side member14A, various shapes need to be prepared for the camera side member14B in accordance with a specification (shape, position, heat radiating property and the like) of the camera18.

The connecting member14constituted as described above is assembled as follows. First, the connecting member14is divided into the barrel side member14A and the camera side member14B, and the barrel side member14A is attached to the small diameter portion12B of the barrel main body12. Next, the actuator44of the optical filter unit40is mounted to the mounting portion58at the upper portion of the barrel side member14A. Further, the filter attaching plate42is attached thereto by inserting the guide pins56of the barrel side member14A into the plularity guide holes42A of the filter attaching plate42and inserting the arm44C of the actuator44to the long hole42B of the filter attaching plate42. Successively, the camera side member14B is connected to the barrel side member14A. Thereby, the connecting member14is mounted to the base end portion of the barrel main body12and the optical filter unit40is included at inside thereof. Further, the connecting member14may be attached to the barrel main body12after integrating the optical filter unit40to inside of the connecting member14.

Operation of the lens barrel10according to the embodiment will be explained as follows.

The connecting member14according to the embodiment is divided into the barrel side member14A and the camera side member14B, and the connecting member14is formed by connecting the barrel side member14A and the camera side member14B. The barrel side member14A needs very high working accuracy for being connected to the barrel main body12, and when the barrel side member14A is molded by a resin, a very expensive die is needed. On the other hand, although the camera side member14B does not need working accuracy as high as that of the barrel side member14A, various shapes are needed in accordance with the specification of the camera18and a number of kinds of dies are needed in molding the camera side member14B by a resin.

When the connecting member14is fabricated without being divided, a number of the connecting members14need to be fabricated by preparing dies with very high accuracy by a number of pieces thereof in accordance with the specification of the camera18. Therefore, there poses a problem that by increasing the specifications of the cameras18, a number of pieces of the connecting members14having high fabrication cost is increased and cost of a total of the lens barrel10is significantly increased.

In contrast thereto, according to the embodiment, the connecting member14is divided into the barrel side member14A and the camera side member14B and therefore, the barrel side member14A having high fabrication cost can be used as a part common to a number of kinds of the cameras18. Therefore, when the cameras18having different specifications are increased, the camera side member14B having fabrication cost lower than that of the barrel side member14A may be prepared in accordance with the kinds of the cameras18and therefore, the cost of the total of the lens barrel10can be reduced.

Further, according to the embodiment, the optical filter unit40is included in the connecting member14, the connecting member14is divided at the position of the optical filter unit40and therefore, a space of containing the optical filter unit40can easily be formed at inside of the connecting member14. That is, by forming the recess portion54at the barrel side member14A of the connecting member14to connect, the space of containing the optical filter unit40can easily be formed at inside of the connecting member14. Further, the recess portion54of the barrel side member14A can easily be formed by only constituting a die for resin molding by a projected shape. Therefore, according to the embodiment, the connecting member14including the optical filter unit40can be fabricated at low cost.

Meanwhile, when the optical filter unit40is integrated to the barrel main body12separately from the connecting member14, holding means (guide frame, base seat or the like) for holding the optical filter unit40is needed and therefore, a problem that the lens barrel10is large-sized by an amount of the holding means is posed. Further, when the optical filter unit40is integrated to the barrel main body12separately from the connecting member14, there poses a problem that a range of moving an optical lens (focus lens22, zoom lens32or the like) is restricted and therefore, an adverse influence is effected on optical properties.

In contrast thereto, according to the embodiment, the optical filter unit40is integrated to the connecting member14, and the connecting member14serves also as holding means of the optical filter unit40. Particularly, according to the embodiment, the barrel side member14A of the connecting member14achieves a role of a guide and achieves a role as a base seat of the actuator44. Therefore, it is not necessary to separately provide holding means of a guide frame, a base seat or the like for holding the optical filter unit40, and the lens barrel10can be downsized.

Further, according to the embodiment, the optical filter unit40is integrated to the connecting member14and therefore, there is not a concern of restricting a range of moving the focus lens22or the zoom lens32by the optical filter unit40, and optical properties can be promoted.

Further, according to the embodiment, the connecting member14is divided at a position of the filter attaching plate42of the optical filter unit40and therefore, the optical filter unit40can easily be integrated to the connecting member14. That is, the optical filter unit40can easily be integrated to inside of the connecting member14by integrating the optical filter unit40and connecting the barrel side member14A and the lens side member14B in a state of dividing the connecting member14into the barrel side member14A and the lens side member14B.

Further, according to the embodiment, the connecting member14is divided at the position of the filter attaching plate42of the optical filter unit40and therefore, by forming the recess portion54at a connecting face of the barrel side member14A, a space for containing the optical filter unit40can easily be formed at inside of the connecting member14.

Further, according to the embodiment, when the optical filter unit40is not used, only the connecting member14may be interchanged, and cost can be reduced.

Further, according to the embodiment, the connecting member14is divided into the barrel side member14A and the camera side member14B and therefore, the barrel side member14A having a high fabrication cost can be used as a common part in a number of kinds of the cameras18. Therefore, when the kinds of the cameras18are increased, the camera side member14B having fabrication cost lower than that of the barrel side member14A may be prepared in accordance with the kinds of the cameras18and therefore, cost of a total of the lens barrel10can be reduced.

Further, although according to the above-described embodiment, the barrel side member14A is formed with the recess portion54for containing the plate attaching plate42, the recess portion may be formed at the camera side member14B, or the recess portion may be formed at both of the barrel side member14A and the camera side member.

Further, although according to the embodiment, the connecting member14is divided at the position of the optical filter unit40, the dividing position is not limited thereto but the connecting member14may divide the side of the barrel main body12and the side of the camera18.

Further, although according to the embodiment, the optical filter unit40is directly integrated to the connecting member14, the optical filter unit40may be contained in a case or the like and the case may be mounted to the connecting member14. That is, the side face of the connecting member14may be formed with an opening in a slit-like shape and the case containing the optical filter unit40may be inserted into the opening to be mounted thereby.

SECOND EMBODIMENT

FIG. 6is a side sectional view showing a constitution of a lens barrel10according to a second exemplary embodiment of the invention. (The same members as those of the first embodiment have the same numerals and symbols as those of the first embodiment.)

Meanwhile, the connecting member14shown inFIG. 6is a member for connecting the barrel main body12and the camera18and is formed substantially in a cylindrical shape. An outer peripheral face of the connecting member14is formed with a groove70in a recess shape over a periphery thereof, a bayonet claw of the camera18is engaged with the groove70to be connected. Further, a method of connecting the camera18and the connecting member14is not particularly limited but the camera18may be screwed to the connecting member14. Further, a built-in type of the camera18in which CCD and a board are exposed may be used, and in this case, a recess portion is formed at the connecting member14and the camera18is screwed thereto in a state of fitting CCD of the camera18.

The connecting member14according to the embodiment is connected to a base end of the small diameter portion12B of the barrel main body12by using a snap in mechanism. A connecting structure thereof will be explained in reference toFIGS. 7A through 7C,FIG. 8, andFIGS. 9A through 9Das follows.

FIG. 7Ais a sectional view taken along a line5-5ofFIG. 6,FIG. 7Bshows only the barrel main body12ofFIG. 7A, andFIG. 7Cshows only the connecting member14. Further,FIG. 8is a perspective view showing a mechanism of connecting the connecting member14and the lens barrel12.FIGS. 9A through 9Dare explanatory views showing a connecting method, showing schematic views viewed from side of the optical axis P.

As shown byFIG. 8, an end face78on a base end side of the barrel main body12is formed with a support portion72to project in a direction of the optical axis P, and a front end of the support portion72is provided with an arm74. The arm74and the support portion72are integrally formed with the barrel main body12by a resin, the arm74is extended in a peripheral direction from the front end of the support portion72. The arm74is formed by a strength to a degree of capable of being sufficiently deformed elastically, and, for example, the front end can elastically be deformed in a direction of being remote from the end face78of the barrel main body12.

The arm74is projected to be formed with a projected portion (claw)76at a face thereof on a side of the barrel main body12. The projected portion76is constituted by a size of being engaged with a through hole86, mentioned later. Further, as shown byFIG. 9A, the projected portion76is formed with an inclined face76A by facing a front end side thereof, and is prevented from being caught by an engaging portion84when the projected portion76is moved in a circumferential direction.

Further, the arm74is arranged at a position at a distance D1from the end face78of the barrel main body12. Further, as shown byFIG. 7B, the arms74are arranged at positions in the peripheral direction equally divided by three.

Meanwhile, as shown byFIG. 8, the connecting member14is projected to be formed with a projected portion82over a periphery thereof at a base end of an inner peripheral face thereof. Further, an inner peripheral face of the connecting member14is projected to be formed with the engaging portion84. The engaging portion84is formed contiguously from the projected portion82and is provided with a sufficient strength to a degree of not being deformed. Further, the engaging portion84is formed in a circumferential direction, and a thickness T1(refer toFIG. 9A) thereof is formed by a dimension the same as the distance D1between the arm74and the end face78. Further, the interval D2between the engaging portion74and the projected portion82is formed to be larger than a thickness T2of the arm74to be able to insert the arm74between the engaging portion84and the projected portion82. Further, an opening portion88penetrating an inner peripheral face and an outer peripheral face is formed between the engaging portion84and the projected portion82. Therefore, it can be optically recognized from outside that the projected portion76of the arm74is engaged with the through hole86, mentioned later.

As shown byFIG. 7C, the engaging portions84are provided at three locations and arranged at positions in a circumferential direction equally divided by three. Further, the respective engaging portions84are formed with the through holes86in the direction of the optical axis P to be engaged with the projected portions76of the arms74.

Next, operation of the lens barrel10constituted as described above will be explained in reference toFIG. 9AthroughFIG. 9D.

When the connecting member14is fixed to the barrel main body12, first, the connecting member14shown inFIG. 9Ais made to cover the small diameter portion12B of the barrel main body12. Further, as shown byFIG. 9B, the end face78of the barrel main body12is pressed to the engaging portion84of the connecting member14.

Next, under the state, the connecting member14is rotated relative to the barrel main body12. Thereby, as shown byFIG. 9C, the front end of the arm74of the barrel main body12is inserted to between the engaging portion84and the projected portion82. At this occasion, the arm74is inserted thereto while being elastically deformed on an outer side by an amount of the projected portion76of the front end.

When pivoting movement of the connecting member14is further progressed, as shown byFIG. 9D, the projected portion76of the arm74is dropped into the through hole86of the engaging portion84by emitting sound. Further, the projected portion76of the arm74is engaged with the through hole86of the engaging portion84by an elastic force of the arm74per se, and the connecting member14is fixed to the barrel main body12.

In this way, according to the lens barrel10of the embodiment, the barrel main body12and the connecting member14are connected by a snap in mechanism. That is, the projected portion76is engaged with the through hole86by the elastic force of the arm74, and the barrel main body12and the connecting member14are connected. When connection has been carried out in this way, the connection is carried out always by a constant force by the elastic force of the arm74and therefore, the connected barrel main body12can be prevented from being warped.

Further, according to the embodiment, the arm74of the snap in mechanism is integrally molded with the barrel main body12, the engaging portion84is integrally molded with the connecting member14and therefore, it is not necessary to separately use a fixing piece of a screw or the like. Further, according to the embodiment, the connecting member14can be connected to the barrel main body12by only rotating the connecting member relative to the barrel main body12and therefore, a tool of a screwdriver or the like is not needed. Therefore, according to the embodiment, the barrel main body12and the connecting member14can be connected easily and at low cost.

Further, according to the embodiment, the connecting member14is engaged with the barrel main body12by rotating the connecting member and therefore, the connecting member14and the barrel main body12can be connected in a state of being positioned in the direction of the optical axis P. That is, the projected portion76of the arm74can be engaged to be connected with the through hole86of the engaging portion84while maintaining a state of bringing the end face78of the barrel main body12into contact with the engaging portion84of the connecting member14to be positioned in the direction of the optical axis P. Particularly, according to the embodiment, by forming the projected portion76of the arm74on a side of the end face78of the barrel main body12, the engaging portion84is pinched by the arm74and the end face78and therefore, a state of bringing the end face88and the engaging portion84into contact with each other can always be ensured. Therefore, according to the embodiment, the connecting member14and the barrel main body12can be connected to be positioned in the direction of the optical axis P and therefore, an optical function can be promoted.

Further, in the above-described embodiment, shapes and numbers of pieces of the projected portions76of the arms74and the through holes86of the engaging portion84are not particularly limited but the projected portions76and the through holes86may be constituted to be engaged with each other thereby. For example, a groove may be formed in place of the through hole86to be engaged with the projected portion76.

Further, in the above-described embodiment, while the projected portion76is formed at the front end of the arm74and the through hole86is formed at the engaging portion84of the connecting member14, these may be reversed. That is, a through hole may be formed at the front end of the arm74and an engaging portion engaging with the through hole may be formed at the engaging portion84. Further, an arm may be formed at the connecting member14and an engaging portion may be formed at the barrel main body12.

It will be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments of the invention without departing from the spirit or scope of the invention. Thus, it is intended that the invention cover all modifications and variations of this invention consistent with the scope of the appended claims and their equivalents.

The present application claims foreign priority based on Japanese Patent Application Nos. JP2005-122751, JP2005-122752 and JP2005-122753, all filed Apr. 20, 2005, the contents of which is incorporated herein by reference.