JP6056534B2 - Lens barrel and imaging device - Google Patents

Description

  The present invention relates to a lens barrel and an imaging apparatus.

A lens barrel (so-called zoom lens) capable of adjusting the focal length changes (zooms) the focal length by relatively moving a plurality of lens groups in the optical axis direction. Further, focus adjustment (focusing) is performed by moving a focusing lens group among a plurality of lens groups, for example.
A cam mechanism is used to guide the movement of the variable power lens group and the focusing lens group (hereinafter referred to as the movable lens group). The cam mechanism includes a cam groove provided at a desired angle with respect to the optical axis in a cam cylinder rotatable around the optical axis, and a cam follower provided so as to project from a holding member of the movable lens. Then, the cam follower is fitted into the cam groove so as to be slidable, and the movable lens group is moved by rotation of the cam cylinder (see Patent Document 1).

JP 08-334670 A

  Incidentally, the imaging optical system in the lens barrel may include a fixed lens group that does not move even during zooming. For this reason, the mechanism for guiding the movement of the movable lens group may be complicated depending on the arrangement of the lens group. For example, when the fixed lens group is positioned between two movable lens groups, it is difficult to guide the movement of the movable lens groups on both sides by one cam cylinder. As a result, there is a problem that the guide mechanism is complicated, and accuracy is lowered due to cost increase and error accumulation.

  An object of the present invention is to provide a lens barrel and an imaging apparatus that can suppress an increase in cost and a decrease in accuracy.

The lens barrel of the present invention includes a first barrel, a cam barrel positioned inside the first barrel, rotating with respect to the first barrel and moving in the optical axis direction, and the cam barrel A plurality of lens groups that are located on the inner side and are arranged in order of the front lens group, the intermediate lens group, and the rear lens group from the subject side, and the cam cylinder rotates with respect to the first cylinder and When moving in the optical axis direction, the front lens group and the rear lens group are guided by a cam mechanism formed in the cam cylinder and moved in the optical axis direction with respect to the first cylinder, when the cam barrel is moved in the optical axis direction while rotating relative to the first cylinder, said intermediate lens group, the configuration and wherein the optical axis direction position with respect to the first cylinder does not change did.
Moreover, the imaging device of the present invention is configured to include the lens barrel.

  According to the present invention, it is possible to provide a lens barrel and an imaging apparatus that can suppress an increase in cost and a decrease in accuracy.

1 is a conceptual diagram of a camera configured by mounting a lens barrel that is an embodiment of the present invention on a camera body. FIG. It is sectional drawing of a lens-barrel. FIG. 3 is an enlarged view of a main part of FIG. 2. It is a disassembled perspective view of a cam cylinder, a fixed cylinder, and a zoom interlocking ring. It is a figure which shows the comparative example corresponding to FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram of a camera 1 configured by mounting a lens barrel 100 according to an embodiment of the present invention on a camera body 10.
In the following drawings, an XYZ orthogonal coordinate system is provided for ease of explanation and understanding. In this coordinate system, when the photographer shoots a horizontally long image with the optical axis OA being horizontal, the direction toward the left side when viewed from the photographer at the position of the camera (hereinafter referred to as a positive position) is the X plus direction. A direction toward the upper side in FIG. Also, the direction toward the subject at the normal position is the Z plus direction. This Z plus direction is also called the front side, and the Z minus direction is also called the back side. Further, movement in a direction parallel to the optical axis OA (that is, the Z axis) is referred to as “straight forward”, and rotation about the optical axis OA is referred to as “rotation”.

The camera 1 includes a camera body 10 and a lens barrel 100. The lens barrel 100 is detachably attached to the camera body 10 by a lens mount LM provided at a base end thereof engaging with a body mount BM of the camera body 10.
The camera body 10 is a so-called digital single-lens reflex camera that includes an image sensor 11 that converts an optical image into an electrical signal, performs image processing on image data obtained by the image sensor 11 and records the image data in a recording unit (not shown). The present invention is not limited to a digital single lens reflex camera.

Next, the lens barrel 100 will be described in detail with reference to FIGS. 2 to 4 in addition to FIG. 1 described above.
FIG. 2 is a cross-sectional view of the lens barrel 100, with the wide-angle end on the upper side and the telephoto end on the lower side across the optical axis OA. FIG. 3 is an enlarged view of a main part in FIG. FIG. 4 is an exploded perspective view of the cam cylinder, the fixed cylinder, and the zoom interlocking ring. FIG. 5 is a diagram showing a comparative example corresponding to FIG. 2 and 4 show the components arranged in the circumferential direction in an overlapping manner.

The lens barrel 100 includes five lens groups (first lens group L1, second lens group L2, third lens group L3, fourth lens group L4, and fifth lens group L5), and the focal length can be changed. This is a so-called zoom lens.
The first lens group L1, the third lens group L3, and the fifth lens group L5 are variable power lens groups that change the focal length, and are rotated in the optical axis OA direction (Z direction) by rotation of a zoom operation ring 111 described later. Each moves straight by a predetermined amount.

The third lens unit L3 is a focusing lens unit that changes the focusing distance (focus position), and moves straight in the direction of the optical axis OA by the rotation of a focus ring 112 described later.
The second lens group L2 and the fourth lens group L4 are fixed lens groups that do not move both at the time of zooming and at the time of focusing.

In the lens barrel 100, an inner fixed cylinder 120 and an outer fixed cylinder 130 are fixed in order from the base end side inside the outer appearance cylinder 110.
A zoom operation ring 111 and a focus ring 112 are rotatably provided on the outer periphery of the appearance cylinder 110.

  The zoom operation ring 111 is connected to an outer cam cylinder 190 to be described later via an interlocking pin 113, and is connected to an inner cam cylinder 150 to be described later via an interlocking pin 113 and a zoom interlocking ring 140. The cam cylinder 190 and the inner cam cylinder 150 are rotatable. As will be described in detail later, the outer cam cylinder 190 guides the movement of the first lens group L1, and the inner cam cylinder 150 guides the movement of the third lens group L3 and the fifth lens group L5.

The focus ring 112 is connected to the focus interlocking ring 115 via the focusing drive motor 114, and the focus interlocking ring 115 can be rotated by the rotation.
An interlocking key 116 is fixed to the focus interlocking ring 115 at the end on the back side.

The interlocking key 116 has a predetermined width and extends to the front side along the inner periphery of the inner cam cylinder 150 described later. The interlocking key 116 has a guide slit parallel to the optical axis OA, and a cam pin 161 of a third lens frame 160 (third lens group L3), which will be described later, is fitted in the guide slit so as to be slidable. Yes.
As a result, when the focus ring 112 is rotated, the interlock key 116 rotates around the optical axis OA via the focus interlock ring 115 and the cam pin 161 of the third lens frame 160 is rotated.

As shown in FIG. 4, the inner fixed barrel 120 guides the movement of the cam barrel cam groove 121 that drives the inner cam barrel 150, the fixed hole 122 that defines the position of the fourth lens group, and the fifth lens group. A fifth rectilinear groove 123 parallel to the optical axis OA.
A zoom interlocking ring 140 is fitted and disposed on the outer periphery of the inner fixed cylinder 120 so as to be rotatable and immovable in the direction of the optical axis OA.

The zoom interlocking ring 140 is connected to the zoom operation ring 111 via the interlocking pin 113, and is rotated by the rotation of the zoom operation ring 111.
As shown in FIG. 4, the zoom interlocking ring 140 includes a cam tube guide groove 141 at a protruding portion toward the back side. The cam cylinder guide groove 141 is formed substantially parallel to the optical axis OA, and as shown in FIG. 3, a cam follower pin 154 of the inner cam cylinder 150 described later is fitted so as to be slidable.
Thereby, the zoom interlocking ring 140 rotates the cam cylinder 150 via the cam follower pin 154 and guides its movement by the rotation of the zoom operation ring 111.

On the inner peripheral side of the inner fixed cylinder 120, an inner cam cylinder 150 is provided so as to be slidable and rotatable and movable in the direction of the optical axis OA.
As shown in FIG. 4, the inner cam cylinder 150 includes a third cam groove 151 that guides the movement of the third lens group L3, a fourth cam groove 152 that guides the movement of the fourth lens group L4, and a fifth lens. And a fifth cam groove 153 for guiding the movement of the group L5.
The inner cam cylinder 150 has a cam follower pin 154 (shown in FIG. 3, not shown in FIG. 4) protruding from the outer periphery. The cam follower pin 154 is slidably fitted into the cam cylinder cam groove 121 of the inner fixed cylinder 120 and penetrates to the outer peripheral side, and a projecting portion toward the outer peripheral side is formed in the cam cylinder guide groove 141 of the zoom interlocking ring 140. It is slidably fitted.

The cam follower pin 154 is rotated along with the rotation of the zoom interlocking ring 140 accompanying the rotation of the zoom operation ring 111, and is moved along the cam tube guide groove 141 according to the displacement of the cam tube cam groove 121 in the inner fixed tube 120. The
As a result, the inner cam barrel 150 moves by a predetermined distance (straight forward movement) in the direction of the optical axis OA while rotating by the rotation of the zoom operation ring 111. As shown in FIG. 2, the inner cam cylinder 150 is located at the rear side end at the wide-angle end, moves to the front side as the focal length increases from here, and is located at the front side end at the telephoto end. Is set to

As shown in FIG. 3, a third lens group L3, a fourth lens group L4, and a fifth lens group L5 are accommodated in the inner cam cylinder 150.
The third lens group L3 is held by the third lens frame 160. The third lens frame 160 is slidably fitted to the inner periphery of the inner cam cylinder 150, and a third cam pin 161 projects from the outer periphery. The third cam pin 161 is slidably fitted to the guide slit of the interlocking key 116 and protrudes to the outer peripheral side, and the tip thereof is fitted to the third cam groove 151 of the inner cam cylinder 150 to be slidable. Yes.

  As a result, when the inner cam cylinder 150 rotates linearly by the rotation of the zoom operation ring 111, the third lens group L3 moves straight and the third cam groove 151 due to the amount of linear movement of the inner cam cylinder 150 and the rotation of the inner cam cylinder 150. It moves along the guide slit of the interlocking key 116 (in the direction of the optical axis OA) by an amount obtained by adding up the displacement amount.

Further, in the third lens unit L3, the third cam pin 161 is rotated by the rotation of the interlocking key 116 by the rotation of the focus ring 112, and the guide slit of the interlocking key 116 according to the displacement of the third cam groove 151 in the inner cam cylinder 150. Along (in the direction of the optical axis OA).
That is, the third lens unit L3 is moved by zooming with the rotation of the zoom operation ring 111 and moved in focus by the rotation of the focus ring 112.

  Here, as described above, the inner cam cylinder 150 moves straight while rotating by the rotation (magnification operation) of the zoom operation ring 111. For this reason, the region of the third cam groove 151 in the inner cam cylinder 150 corresponding to the guide angle range of the third cam pin 161 by the interlocking key 116 varies depending on the focal length.

  This is because the amount of movement of the third lens unit L3 necessary for focusing from the infinite distance to the closest distance varies depending on the focal length, so the region in the third cam groove 151 corresponding to the third cam pin 161 is changed. This is because it is possible to focus from the infinity distance to the closest distance by rotating the focus ring 112 within a certain angle range regardless of the focal length.

  That is, the third cam groove 151 causes the third lens unit L3 to move from the infinite distance to the closest distance by rotating the focus ring 112 within a certain angle range according to the position of the third cam pin 161 (ie, focal length). It is formed in a shape that can move to a range that allows focusing.

  The fourth lens unit L4 is held by the fourth lens frame 170. The fourth lens frame 170 is slidably fitted to the inner circumference of the inner cam cylinder 150, and a fourth cam pin 171 is provided on the outer circumference. The fourth cam pin 171 is slidably fitted in the fourth cam groove 152 of the inner cam cylinder 150 and protrudes to the outer peripheral side, and the tip is fitted in the fixing hole 122 of the inner fixing cylinder 120.

  Here, the fourth cam groove 152 of the inner cam cylinder 150 and the cam cylinder cam groove 122 of the inner fixed cylinder 120 have regions having the same inclination with respect to the optical axis OA direction. The location where the inner cam follower pin 154 is located and the location where the fourth cam pin 171 is located within the fourth cam groove 152 are configured to have the same inclination with respect to the optical axis OA direction. That is, the fourth cam groove 152 in the inner cam cylinder 150 is formed in a shape for moving and operating the fourth cam pin 171 so as to cancel the straight movement due to the rotation of the inner cam cylinder 150 accompanying the operation of the zoom operation ring 111. .

  That is, the fourth cam groove 152 is configured such that the inner cam cylinder 150 rotates and moves straight through the fourth cam pin 171 (the tip is fitted in the fixing hole 122 of the inner fixed cylinder 120) in the fourth lens frame 170. Also, it is shaped to move relatively so as not to move with respect to the inner fixed cylinder 120.

Thus, when the inner cam cylinder 150 is rotated by the guidance of the zoom operation ring 111, the inner cam cylinder 150 moves straight according to the displacement of the cam cylinder cam groove 121 in the inner fixed cylinder 120. The cam groove 152 moves relative to the inner cam cylinder 150 so that the position of the fourth cam pin 171 relative to the inner fixed cylinder 120 does not change.
As a result, the position of the fourth lens frame 170 (fourth lens unit L4) is maintained (that is, fixed) with respect to the inner fixed cylinder 120 regardless of the guidance of the zoom operation ring 111.

The fixing hole 122 in the inner fixed cylinder 120 into which the tip of the fourth cam pin 171 is fitted may be a round hole that does not allow movement in the optical axis OA direction at all.
In this case, the position of the fourth lens frame 170 (fourth lens unit L4) is absolutely fixed with respect to the inner fixed cylinder 120, and takes precedence over the movement by the fourth cam groove 152.
In addition, the fixing hole 122 is formed in a long hole shape in the optical axis OA direction so that the fourth cam pin 171 is slightly allowed to move in the optical axis OA direction, and the fourth cam groove 151 is formed in the fourth lens frame 170. The positioning of the (fourth lens unit L4) may be performed with priority over the fixing hole 122.
When the fixing hole 22 is a round hole, the fourth lens unit L4 that moves together with the fourth cam pin 171 is completely fixed to the inner fixed cylinder 120.
When the fixing hole 22 is a long hole, the fourth lens group L4 that moves together with the fourth cam pin 171 remains fixed to the inner fixing cylinder 120, but is stronger by the fourth cam groove 152 of the inner cam cylinder 150. Be bound.
Whether the fixing hole 22 is a round hole or a long hole is whether the fourth lens group L4 is fixed to the inner fixed cylinder 120, or the positional relationship between the fourth lens group L4, the third lens group L3, and the fifth lens group L5. It is selected according to which is given priority.
When priority is given to fixing the fourth lens group L4 to the inner fixed cylinder 120, the fixing hole 22 is a round hole, and when the positional relationship between the fourth lens group L4, the third lens group L3, and the fifth lens group L5 is given priority, A long hole is selected as the fixing hole 22.

The fifth lens unit L5 is held by the fifth lens frame 180. The fifth lens frame 180 is slidably fitted to the inner circumference of the inner cam cylinder 150, and a fifth cam pin 181 is projected from the outer circumference.
The fifth cam pin 181 is slidably fitted in the fifth cam groove 153 of the inner cam cylinder 150 and protrudes to the outer peripheral side, and the tip thereof slides into the fifth rectilinear groove 123 formed in the inner fixed cylinder 120. It is movably fitted.

  As a result, when the inner cam cylinder 150 rotates and rotates straight by the rotation of the zoom operation ring 111, the fifth lens group L5 moves straight and the fifth cam groove 153 generated by the rotation of the inner cam cylinder 150 and the inner cam cylinder 150 rotates. It moves along the fifth rectilinear groove 123 of the inner fixed cylinder 120 (in the direction of the optical axis OA) by an amount obtained by adding up the displacement amount.

The outer fixed cylinder 130 includes a first rectilinear groove that guides the movement of the first lens unit L1 on the outer peripheral surface, and supports the lens unit L2 on the inner peripheral side.
An outer cam cylinder 190 having a first cam groove 191 is provided on the outer peripheral side of the outer fixed cylinder 130 so as to be relatively rotatable and not relatively movable in the optical axis OA direction.
A moving frame 200 that holds the lens unit L1 is provided on the outer peripheral side of the outer cam cylinder 190 so as to be movable in the direction of the optical axis OA.

  The moving frame 200 is positioned between the outer periphery of the outer cam cylinder 190 and the inner periphery of the external appearance cylinder 110, and holds the lens group L1 at the tip. A cam follower pin 201 projects from the inner periphery of the base end side (back side) of the moving frame 200. The cam follower pin 201 passes through the first cam groove 191 of the outer cam cylinder 190 so as to be slidable, and the tip is fitted in the first rectilinear groove of the outer fixed cylinder 130 so as to be slidable.

  As a result, when the outer cam cylinder 190 is rotated by the guidance of the zoom operation ring 111, the first cam groove 191 guides the cam follower pin 201 of the moving frame 200, and the moving frame 200 responds to the displacement of the first cam groove 191. It moves in the direction of the optical axis OA along the first rectilinear groove of the outer fixed cylinder 130.

In the lens barrel 100 configured as described above, the outer cam barrel 190 is rotated by the rotation of the zoom operation ring 111 by the user and the first lens unit L1 is moved by a predetermined amount in the direction of the optical axis OA. As the cam barrel 150 rotates, the third lens unit L3 and the fifth lens unit L5 move by a predetermined amount in the direction of the optical axis OA.
The focal length continuously changes between the wide-angle end shown on the upper side of FIG. 2 and the telephoto end shown on the lower side. Further, as the focus ring 112 rotates, the interlocking key 116 rotates and the lens unit L3 moves by a predetermined amount in the direction of the optical axis OA, and the focusing distance (focus position) changes.

  Here, as described above, the fourth lens unit L4, which is a fixed lens unit, is provided inside the inner cam cylinder 150 that moves linearly while rotating at the time of zooming. The cam groove 152 is relatively moved so that the position with respect to the inner fixed cylinder 120 does not change. For this reason, the fourth lens unit L4 does not move in the direction of the optical axis OA even by a zooming operation, and is fixed at a predetermined position.

  With the above-described configuration, the fourth lens group L4 that is a fixed lens group, and the third lens group L3 and the fifth lens group L5 that are moved forward and backward with the lens group therebetween are arranged in one inner cam cylinder 150. It can be accommodated inside. As a result, the cost can be reduced by simplifying the configuration, and the amount of movement of the third lens unit L3 and the fifth lens unit L5 can be increased.

  That is, FIG. 5 shows a comparative example corresponding to FIG. 3 when the configuration of the present application is not applied. The comparative example shown in FIG. 5 includes a third cam cylinder 53 that drives the third lens group L3 and a fifth cam cylinder 55 that drives the fifth lens group L5, and the zoom interlocking ring 51 includes both. It is formed long on the back side so as to cover.

  In the third cam cylinder 53 and the fifth cam cylinder 55, the cam pins (the third cam cylinder pin 531 and the fifth cam cylinder pin 551) respectively implanted are fitted in the cam grooves of the zoom interlocking ring 51, and this zoom interlocking. The ring 52 is rotationally driven. In FIG. 5, the other components common to FIG. 3 are denoted by the same reference numerals as those in FIG.

  As in the comparative example shown in FIG. 5, the third lens unit L3 and the fifth lens unit L5 are configured to be driven independently by the third cam cylinder 53 and the fifth cam cylinder 55, respectively. However, the amount of movement of the third lens unit L3 and the fifth lens unit L5 is limited because it is difficult to increase the longitudinal length of the third cam barrel 53 and the fifth cam barrel 55. The

  Further, in order to drive the fifth cam cylinder 55, the zoom interlocking ring 51 extends to the back side, thereby limiting the arrangement space for electric parts and the like. In the configuration of the present application shown in FIG. 3, a space is formed between the zoom interlocking ring 140 and the focus interlocking ring 115 located on the back side thereof, and the electrical component 210 and the like can be disposed here.

  Furthermore, in the comparative example configuration of FIG. 5, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 are held by different members, so it is difficult to combine the mutual positions with high accuracy. . On the other hand, in the configuration of the present application, since the third lens group L3, the fourth lens group L4, and the fifth lens group L5 are held by one inner fixed cylinder 120, the mutual positions can be set with high accuracy. it can.

As described above, this embodiment has the following effects.
(1) According to the present embodiment, the fourth lens group L4, which is a fixed lens group disposed inside the inner cam cylinder 150 that rotates and moves straight during zooming, is the fourth cam group in the inner cam cylinder 150. The groove 152 is relatively moved so that the position with respect to the inner cam cylinder 150 does not change.
As a result, the fourth lens group L4, which is a fixed lens group, and the third lens group L3 and the fifth lens group L5, which are moved forward and backward with the lens group therebetween, are accommodated in one inner cam cylinder 150. This makes it possible to reduce the cost by simplifying the configuration and to increase the amount of movement of the third lens unit L3 and the fifth lens unit L5, thereby increasing the degree of freedom in optical design.

(2) The fourth lens group L4, which is a fixed lens group, and the third lens group L3 and the fifth lens group L5, which are moved forward and backward with the lens group therebetween, are accommodated in one inner cam cylinder 150. By simplifying the configuration, the space efficiency is improved, the size and weight can be reduced, and the arrangement space for the electrical components and the like can be easily secured.

(3) The third lens group L3, the fourth lens group L4, and the fifth lens group L5 can be held in one inner fixed cylinder 120, and the mutual positions can be set with high accuracy.

(Deformation)
The present invention is not limited to the above-described embodiment, and various modifications and changes as described below are possible, and these are also within the scope of the present invention.
In this embodiment, the fourth lens unit L4, which is a fixed lens unit, and the third lens unit L3 and the fifth lens unit L5 that are moved forward and backward with the lens unit interposed therebetween are used as one inner cam cylinder. This is an example applied to a configuration housed in 150. However, the arrangement and number of the fixed lens group and the movable lens group are not limited to this configuration, and can be changed as appropriate.

  In addition, although embodiment and a deformation | transformation form can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited to the embodiment described above.

  1: camera, 10: camera body, 100: lens barrel, 120: inner fixed barrel, 150: inner cam barrel, 151: third cam groove, 152: fourth cam groove, 153: fifth cam groove, L1: 1st lens group, L2: 2nd lens group, L3: 3rd lens group, L4: 4th lens group, L5: 5th lens group

Claims (7)

A first tube;
A cam cylinder positioned inside the first cylinder, rotating with respect to the first cylinder and moving in the optical axis direction;
A plurality of lens groups located inside the cam cylinder and arranged in order of the front lens group, the intermediate lens group, and the rear lens group from the subject side;
When the cam cylinder rotates relative to the first cylinder and moves in the optical axis direction, the front lens group and the rear lens group are guided by a cam mechanism formed on the cam cylinder. Moving in the optical axis direction with respect to the first tube,
When the cam barrel is moved in the optical axis direction while rotating relative to the first cylinder, said intermediate lens group, the lens position of the optical axis direction does not change with respect to the first cylinder Tube. The lens barrel according to claim 1,
The intermediate lens group is arranged in the optical axis direction with respect to the first cylinder by an intermediate lens group cam mechanism formed in the cam cylinder so as to cancel the rotation with respect to the first cylinder and the movement in the optical axis direction. A lens barrel whose position does not change . The lens barrel according to claim 1 or 2,
Said intermediate lens group, a lens barrel that is fixed to the first cylinder. The lens barrel according to claim 1 or 2,
Said intermediate lens group, the formed in the first cylinder, is supported against the first cylinder by a long hole extending long in the optical axis direction,
Lens barrel. The lens barrel according to any one of claims 1 to 4,
It said front lens group, a lens barrel is the focusing lens group which performs focus adjustment by moving the optical axis direction. The lens barrel according to any one of claims 1 to 5,
A fixed lens group disposed closer to the subject than the plurality of lens groups;
A movable lens group disposed closer to the subject than the fixed lens group ;
Further comprising a lens barrel to.   An imaging device comprising the lens barrel according to any one of claims 1 to 6.

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