JP5470714B2 - Lens barrel, optical equipment - Google Patents

Description

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

2. Description of the Related Art Conventionally, a lens barrel having a configuration in which a support member that supports a lens is linearly moved in the optical axis direction by a drive member that is rotated by a driving force of a motor (see, for example, Patent Document 1). .
JP-A-8-220411

In this type of lens barrel, if the dimensional accuracy and assembly accuracy of the lens driving member are lowered, the lens to be driven may be decentered and the optical performance may be lowered.
An object of the present invention is to provide a lens barrel and an optical apparatus with improved optical performance.

The present invention relates to a reference member integrally formed with a reference surface attached to the camera body, a lens movable with respect to the reference member, and parallel to the optical axis of the lens by a driving force from a driving source. An optical apparatus comprising a lens barrel having a lens driving member that rotates around a rotation axis and drives the lens in an optical axis direction of the lens, wherein the lens driving member receives a driving force from the driving source. The input unit that rotates around the rotation axis by being received and the input unit are separate members that are positioned on the inner peripheral side of the input unit and are integrally engaged with the input unit at the engagement unit. And a driving unit that drives the lens in the optical axis direction by rotating around the rotation axis, and the engagement unit includes a groove provided in one of the input unit and the driving unit. , To the other of the input unit and the drive unit A projection portion that is inserted into the groove portion and engages the input portion and the drive portion in a state in which relative movement of the input portion and the drive portion in the optical axis direction is allowed. The reference member is a first member located on the subject side in the optical axis direction with respect to the drive unit, and a second member located on the camera body side in the optical axis direction with respect to the drive unit. The input unit is supported by the reference member in a state in which the input unit is movable in the direction of the optical axis with respect to the reference member, and the drive unit is configured to move the optical axis with respect to the reference member. The input unit is supported by the reference member in a state in which movement in the direction is restricted, and a gear for receiving a driving force from the driving source is formed on the outer peripheral surface of the input unit, and the inner peripheral side Facing the first member of the reference member at a surface and rotating relative to the reference member It is rotatable about,
The driving unit is formed with a driving mechanism for driving the lens on an inner peripheral surface thereof, and is opposed to the first member of the reference member on the outer peripheral surface, and rotates with respect to the reference member. The main body is rotatable about an axis, the first member restricts movement of the drive unit toward the subject in the optical axis direction, and the second member restricts movement of the drive unit in the optical axis direction. The present invention relates to an optical apparatus characterized in that movement to the side is restricted .

In the present invention, the first member is a cylindrical body, a lens different from the lens driven by the lens driving member is held therein, and the second member is an annular member. The attachment member to the camera body is preferably connected.
Further, in the present invention, a lens holding frame that moves in the optical axis direction by rotation of the drive unit is provided, and the lens holding frame has a through portion through which a straight guide key fixed to the second member is inserted. It is preferable.

  According to the present invention, it is possible to provide a lens barrel and an optical apparatus with improved optical performance.

Hereinafter, an embodiment of a lens barrel to which the present invention is applied will be described with reference to the drawings.
FIG. 1 is a cross-sectional view including the optical axis of the lens barrel of the embodiment.
FIG. 2 is a view of the lens barrel shown in FIG. 1 as viewed from the camera body side in the optical axis direction.
In order to facilitate understanding, a three-dimensional coordinate system composed of an X axis, a Y axis, and a Z axis is set in each drawing.

  The lens barrel 1 is an interchangeable lens barrel that is detachably attached to the camera body 100, and includes a first lens group L1, a second lens group L2, an aperture unit 10, a fixed barrel 20, a reinforcing ring 30, and two groups. The frame 40, the drive unit 50 (refer FIG. 2), the drive ring 60, etc. are provided.

The first lens group L1 and the second lens group L2 form an imaging optical system that guides subject light to an imaging unit (not shown) provided in the camera body 100. The optical axis A of the photographing optical system and the Z axis shown in the figure are parallel to each other.
The first lens unit L1 is fixed to the end of the lens barrel 1 on the subject side in the optical axis direction. The second lens unit L2 is disposed closer to the camera body side in the optical axis direction than the first lens unit L1, and can advance and retract in the optical axis direction. The lens barrel 1 adjusts the in-focus state of the photographic optical system by moving the second lens unit L2 back and forth in the optical axis direction, thereby focusing, for example, on the main subject.

  The aperture unit 10 adjusts the amount of subject light passing through the photographing optical system formed by the first lens group L1 and the second lens group L2, and includes a first lens group L1 and a second lens group L2. Arranged between. The aperture unit 10 includes a known iris diaphragm device having a plurality of aperture blades.

The fixed cylinder 20 is a cylinder whose movement with respect to the camera body 100 is restricted in a state where the lens barrel 1 is mounted on the camera body 100.
The reinforcing ring 30 is an annular member connected to the end of the fixed cylinder 20 on the optical axis direction camera body side. A lens mount 31 for connecting the lens barrel 1 to the camera body 100 and a rectilinear guide key 32 for rectilinearly guiding a second group holding frame 40 described later are fixed to the reinforcing ring 30 with screws.

The second group holding frame 40 is a frame that holds the second lens group L2, and the overall shape is formed in an annular shape. The second group holding frame 40 includes a main body portion 41 that is a portion that holds the second lens group L2, and a protruding portion 42 that is formed to protrude from the outer peripheral surface of the main body portion 41 to the outer diameter side. As shown in FIG. 2, for example, three overhang portions 42 are formed at substantially equal intervals around the optical axis. The linear guide key 32 described above passes through the overhanging portion 42, and the moving direction of the second group holding frame 40 is limited to a direction parallel to the optical axis A.
Male helicoids 43 are formed at the distal ends of the overhang portions 42, and these male helicoids 43 are screwed into female helicoids 71 formed on a helicoid ring 70 described later.

As shown in FIG. 2, the drive unit 50 includes an actuator 51 and a reduction gear train 52.
The actuator 51 is a power source that drives the second lens unit L2 that is a focus lens in the optical axis direction. For example, the actuator 51 operates according to an autofocus instruction signal transmitted from the camera body 100, and this rotational force is a reduction gear. It is transmitted to the second group holding frame 40 via the row 52 and a driving ring 60 described later. As the actuator 51, a vibration actuator such as an ultrasonic motor, a DC motor, or the like can be used.
The lens barrel 1 can also be manually focused to move the second lens unit L2 back and forth in the optical axis direction according to the rotation operation of the focus operation ring 33. Description and illustration of the power transmission mechanism between the focus operation ring 33 and the drive ring 60 are omitted.

The drive ring 60 is a member that transmits the output of the actuator 51 and the rotational force of the focus operation ring 33 to the second group holding frame 40 described above.
The drive ring 60 includes a helicoid ring 70 that is mechanically engaged with the second group holding frame 40, and a gear ring 80 that includes a gear 81 that meshes with the final gear 52a included in the reduction gear train 52. It is formed by two members. Each of the helicoid ring 70 and the gear ring 80 is a resin molded product formed of a synthetic resin material.

FIG. 3 is a diagram showing a helicoid ring provided in the lens barrel shown in FIG.
FIG. 4 is a view showing a gear ring provided in the lens barrel shown in FIG.

The helicoid ring 70 is an annular member disposed on the inner diameter side of the fixed cylinder 20 and the reinforcing ring 30, and is provided on the inner peripheral surface of the above-described second group holding frame 40 as shown in FIG. 3. A female helicoid 71 that is screwed into the male helicoid 43 is formed.
On the outer peripheral surface of the helicoid ring 70, a protruding portion 72 is formed that protrudes in the shape of a collar on the outer diameter side. As shown in FIG. 3, for example, three protrusions 72 are provided at substantially equal intervals around the optical axis. As shown in FIG. 1, the protruding portions 72 are inserted into the gaps 21 formed between the fixed cylinder 20 and the reinforcing ring 30.

A first thrust receiving portion 34 is formed on the reinforcing ring 30 so as to protrude in the shape of a collar on the inner diameter side, and a surface portion of the protruding portion 72 facing the camera body side is formed by the first thrust receiving portion 34. It is in contact with the surface facing the subject side.
Furthermore, the end surface portion of the helicoid ring 70 on the subject side in the optical axis direction is in contact with a second thrust receiving portion 22 that is a plane perpendicular to the optical axis Z formed in the fixed cylinder 20. Accordingly, the movement of the helicoid ring 70 in the direction of the subject in the optical axis direction is restricted by the second thrust receiving portion 22 and the movement toward the camera body side in the optical axis direction is restricted by the first thrust receiving portion 34, respectively. Movement in the optical axis direction (hereinafter referred to as a thrust direction as appropriate) is substantially impossible.

Further, the outer peripheral surface of the helicoid ring 70 is opposed to the inner peripheral surface of the fixed cylinder 20. Further, only a minute gap that allows rotation around the optical axis of the helicoid ring 70 is formed between the outer peripheral surface of the helicoid ring 70 and the inner peripheral surface of the fixed cylinder 20. Movement of the lens barrel 1 in the radial direction (hereinafter referred to as a radial direction as appropriate) with respect to the fixed barrel 20 is substantially impossible.
As described above, the position of the helicoid ring 70 in the thrust direction and the radial direction with respect to the fixed cylinder 20 is constrained, and the helicoid ring 70 rotates around the optical axis in a state where the center of rotation substantially coincides with the optical axis A. . As a result, even when the helicoid ring 70 rotates when the second group holding frame 40 is driven, the rotation center thereof is suppressed from being inclined with respect to the optical axis A.

  On the outer peripheral surface of the end of the helicoid ring 70 on the subject side in the optical axis direction, a groove 73 into which an engagement protrusion 82 formed on a gear ring 80 described later is inserted is formed. For example, three groove portions 73 extend substantially parallel to the optical axis A and are provided at substantially equal intervals around the optical axis.

  The gear ring 80 is an annular member disposed on the outer diameter side of the helicoid ring 70, and a gear 81 that meshes with the final gear 52a of the reduction gear train 52 is formed on a part of the outer peripheral surface thereof ( (See FIG. 2).

  As shown in FIG. 1, the inner peripheral surface of the gear ring 80 faces the outer peripheral surface of the fixed cylinder 20. Only a minute gap that allows rotation around the optical axis of the gear ring 80 is formed between the inner peripheral surface of the gear ring 80 and the outer peripheral surface of the fixed cylinder 20. Movement in the radial direction with respect to the fixed cylinder 20 is substantially impossible. On the other hand, a gap is formed in the thrust direction between the gear ring 80 and the fixed cylinder 20, and the position of the gear ring 80 in the thrust direction with respect to the fixed cylinder 20 is not constrained.

  As shown in FIG. 4, an engagement protrusion 82 is formed on the inner peripheral surface of the gear ring 80 so as to protrude toward the inner diameter side. For example, three engagement protrusions 82 are provided at substantially equal intervals around the optical axis, and are inserted into grooves 73 formed on the outer peripheral surface of the helicoid ring 70 as shown in FIG. . As a result, the gear ring 80 and the helicoid ring 70 are integrally engaged, and rotate when the rotational force of the actuator 51 is transmitted to the gear ring 80. A gap (backlash) that allows the gear ring 80 to move in the optical axis direction with respect to the helicoid ring 70 is formed between the engagement protrusion 82 and the groove 73. Thus, unlike the helicoid ring 70, the position of the gear ring 80 in the thrust direction is not particularly restricted.

  In the lens barrel 1 of the first embodiment, for example, the actuator 51 is operated according to an autofocus instruction signal transmitted from the camera body 100, or the focus operation ring 33 is operated by a photographer or the like. As a result, the drive ring 60 (helicoid ring 70 and gear ring 80) rotates around the optical axis. Since the rotation of the second group holding frame 40 around the optical axis is restricted by the rectilinear guide key 32, when the helicoid ring 70 is rotated, the second group holding frame 40 is linearly moved in the optical axis direction by being guided by the helicoid.

The lens barrel 1 of the embodiment described above has a radial direction and a radial direction with respect to the fixed cylinder 20 of the helicoid ring 70 that is directly engaged with the second group holding frame 40 that holds the second lens group L2 that is the focus lens group. Since the movement in both directions is restricted, the rotation center of the helicoid ring 70 during rotation is suppressed from being inclined with respect to the optical axis Z. Therefore, the second lens group can be surely moved straight in the optical axis direction, and the optical performance of the photographing optical system is improved.
On the other hand, the gear ring 80 including the gear meshing with the final gear is not restrained in the position in the optical axis direction. However, if the output of the actuator can be transmitted to the helicoid ring, the gear ring 80 is highly assembled to the fixed cylinder 20. Precision is not required.

In addition, the drive ring 60 provided in the lens barrel 1 of the embodiment is a resin molded product formed of a synthetic resin material, but is constituted by two members, a helicoid ring 70 and a gear ring 80. The effect that molding is easy is obtained.
For example, a driving ring in which the helicoid ring 70 and the gear ring 80 are integrated is assumed (hereinafter referred to as a driving ring of a comparative form). The drive ring of this comparative form is an annular member in which a gear that meshes with the reduction gear train is formed on the outer peripheral surface, and a female helicoid that is screwed into the male helicoid 43 of the second group holding frame 40 is formed on the inner peripheral surface. is there.

Here, in general, in the molding of a resin molded product, a part requiring the most dimensional accuracy is specified, and the position of the gate and the injection pressure are determined in consideration of this part.
However, since the drive ring of the comparative form is formed on the inner peripheral surface of the female helicoid and the outer peripheral surface of the female helicoid, it is difficult to ensure the dimensional accuracy of both the gear and female helicoid. is there. In the driving ring of the comparative form, when the dimensional accuracy of one of the female helicoid and the gear is reduced, the influence of the reduction of the dimensional accuracy is exerted on the other. there is a possibility.

  On the other hand, in the drive ring 60 provided in the lens barrel 1 of the present embodiment, the helicoid ring 70 and the gear ring 80 are separate members, and can be formed separately. Both accuracy and dimensional accuracy of the gear 81 can be ensured. Therefore, it is possible to accurately advance the second lens unit L2 in the optical axis direction. Further, since the helicoid ring 70 and the gear ring 80 are simple in shape, they can be easily molded, and the dimensional accuracy can be easily increased.

[Deformation]
The present invention is not limited to the embodiment described above, and various modifications and changes as shown below are possible, and these are also included in the technical scope of the present invention.
(1) Although the lens barrel of the embodiment is configured to drive the second lens group in the optical axis direction with a helicoid, the present invention is not limited thereto, and the second lens group may be driven with a cam mechanism, for example. .
(2) In the drive ring of the embodiment, the gear ring and the helicoid ring are engaged at three positions. However, these engagement positions (the number of the straight advance grooves and the engagement protrusions) are the gear ring and the helicoid ring. Is not limited to this as long as it can rotate integrally. In the embodiment, the rectilinear groove is provided on the helicoid ring and the engaging protrusion is provided on the gear ring. However, the present invention is not limited thereto, and the rectilinear groove is provided on the drive ring side, and the engaging protrusion is provided on the helicoid ring side. May be.
(3) The lens barrel of the embodiment is an interchangeable lens barrel that is detachably attached to the camera body. However, the lens barrel of the present invention is not limited to this, and may be integrated with the camera body. .

It is sectional drawing containing the optical axis of the lens-barrel of embodiment. It is the figure which looked at the lens-barrel shown in FIG. 1 from the camera body side of the optical axis direction. It is a figure which shows the helicoid ring with which the lens barrel shown in FIG. 2 was equipped. It is a figure which shows the gear ring with which the lens barrel shown in FIG. 2 was equipped.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Lens barrel: 30 Reinforcement ring: 40 2nd group holding frame: 50 Drive unit: 60 Drive ring: 70 Helicoid ring: 73 Groove part: 80 Gear ring: 82 Engagement protrusion: L2 2nd lens group

Claims (3)

A reference member configured integrally with a reference surface to be attached to the camera body;
A lens movable with respect to the reference member;
An optical apparatus comprising a lens barrel having a lens driving member that rotates around a rotation axis parallel to the optical axis of the lens by a driving force from a driving source and drives the lens in the optical axis direction of the lens. ,
The lens driving member is
An input unit that rotates around the rotation axis by receiving a driving force from the driving source;
The lens is a member separate from the input unit, and is positioned on an inner peripheral side of the input unit, and is engaged with the input unit integrally by an engagement unit and rotates around the rotation axis. And a drive unit for driving in the optical axis direction,
The engaging portion includes a groove portion provided in one of the input portion and the driving portion, and a protrusion portion provided in the other of the input portion and the driving portion and inserted into the groove portion, and the input Engaging the input unit and the drive unit in a state in which relative movement between the unit and the drive unit in the optical axis direction is allowed,
The reference member includes a first member located on the subject side in the optical axis direction with respect to the drive unit, and a second member located on the camera body side in the optical axis direction with respect to the drive unit. Have
The input unit is supported by the reference member in a state that allows movement in the direction of the optical axis with respect to the reference member,
The drive unit is supported by the reference member in a state where movement in the direction of the optical axis is restricted with respect to the reference member,
The input portion is formed with a gear for receiving a driving force from the drive source on an outer peripheral surface thereof, and is opposed to the first member of the reference member on an inner peripheral surface thereof. rotatable der about said rotation axis with respect to is,
The driving unit is formed with a driving mechanism for driving the lens on an inner peripheral surface thereof, and is opposed to the first member of the reference member on the outer peripheral surface, and rotates with respect to the reference member. Can rotate around an axis,
The first member restricts movement of the drive unit toward the subject in the optical axis direction, and restricts movement of the drive unit toward the camera body in the optical axis direction by the second member. about,
Optical equipment characterized by. The optical instrument according to claim 1,
The first member is a cylindrical body, and a lens different from the lens driven by the lens driving member is held therein,
The second member is an annular member, and an attachment member to the camera body is connected;
Optical equipment characterized by. The optical apparatus according to claim 2,
A lens holding frame that moves in the optical axis direction by rotation of the drive unit;
The lens holding frame has a penetrating portion through which a straight guide key fixed to the second member is inserted;
Optical equipment characterized by.

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