JP7046597B2 - Lens barrel and optical equipment - Google Patents

Description

The present invention relates to a lens barrel mounted on an optical device such as a camera and an optical device including the lens barrel.

Lens barrels used in optical devices such as digital cameras and video cameras may be equipped with an adjustment mechanism that shifts the position of the constituent lenses and adjusts tilt and eccentricity in order to improve the optical performance of the lens. .. The adjustment mechanism is generally configured to be adjustable after assembling the lens barrel to cancel the cumulative tolerance of each component.

The technique disclosed in Patent Document 1 discloses a technique in which a lens holding frame is supported by a cam follower and an eccentric portion is provided on the cam follower to adjust the tilt and eccentricity of the lens. On the other hand, as the cam member with which the cam follower is engaged, a cam groove in which the tilt angle (advance angle) changes according to the operating region is generally used for zooming and focusing drive.

Japanese Unexamined Patent Publication No. 2013-238792

However, when the position of the lens is adjusted as in Patent Document 1, the cam follower tilts the cam groove by performing zoom and focus operations at the contact position with the cam groove in the cam groove where the lens is adjusted. Move to the contact position with the cam groove with a different angle. As a result, there is a problem that the amount of tilting and the amount of eccentricity of the lens at the position where the position is adjusted changes due to the change in the tilt angle of the cam groove after the zoom or focus operation.

Therefore, an object of the present invention is to provide a lens barrel and an optical device provided with a lens barrel in which the position of the lens group to be adjusted does not change in the entire operating range of the cam groove of the cam member.

In order to achieve the above object, in the lens barrel of the present invention, the lens holding member that holds the lens, the cam follower that supports the lens holding member, and the first groove in which the cam follower engages are the light of the lens. A cam groove is provided in which the cam follower engages with the guide member that is extended in the direction of the axis and guides the lens holding member in the direction of the optical axis, and the advancing angle changes according to the rotation angle. The cam follower includes a cam member that moves the lens holding member in the direction of the optical axis by rotating, and the cam follower has a first cylindrical portion, a second cylindrical portion, and a fourth cylindrical portion that are arranged coaxially with each other. It has a portion and a third cylindrical portion eccentrically arranged with respect to the second cylindrical portion, and the first cylindrical portion engages with the first groove portion of the guide member to obtain the said portion. The second cylindrical portion engages with the second groove portion provided on the lens holding member, and the third cylindrical portion is provided on the lens holding member and intersects the second groove portion. It is characterized in that it engages with a third groove portion extended in a direction, and the fourth cylindrical portion engages with the cam groove of the cam member.

According to the present invention, the lens group can be held with high accuracy in the entire operating range of the cam groove of the cam member without changing the amount of tilting of the lens group by a simple configuration.

It is an exploded perspective view of the lens barrel which is an example of embodiment of this invention. It is sectional drawing which follows the optical axis direction of a lens barrel. It is a perspective view of a lens barrel. It is a perspective view of the lens group holding member. It is an enlarged view of the 2nd groove part and the 3rd groove part. It is a perspective view of a cam follower. It is sectional drawing which shows the state which the cam follower engaged with each member, and was fixed to the lens group holding member. It is sectional drawing at the position where the cam follower is rotated and the third cylindrical portion is most displaced in the optical axis direction. It is sectional drawing at the position where the cam follower is rotated and the third cylindrical portion is most displaced in the optical axis direction. It is a figure which shows typically the positional relationship between the rotation amount of a cam follower when the cam follower is rotated, and the 2nd cylindrical part, the 3rd cylindrical part, the 2nd groove part, and the 3rd groove part.

Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view of a lens barrel, which is an example of an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the optical axis direction of the lens barrel. As shown in FIGS. 1 and 2, the lens barrel of the present embodiment is mounted on an optical device such as a camera, and holds a lens group 101 and a lens group 101 that form a part of a photographing optical system. A holding member (lens holding member) 102, a cam member 105, and a guide member 104 are provided. A cam follower 103 is attached to the lens group holding member 102, and the lens group holding member 102 is held by the cam member 105 and the guide member 104 together with the cam follower 103.

The cam follower 103 is attached to the lens group holding member 102 by the fastening member 106 and the nut member 107, and this point will be described later. The cam member 105 is provided with a plurality of cam grooves 105a in the circumferential direction, and the cam grooves 105a engage with a fourth cylindrical portion 103d (see FIG. 6) provided in the cam follower 103.

The guide member 104 is provided with a plurality of first groove portions 104a extending in the optical axis A direction with a constant width in the circumferential direction, and the first groove portions 104a are provided with the first cylindrical portion 103a (1) provided in the cam follower 103. (See FIG. 6).

The cam member 105 and the guide member 104 are relative to each other around the optical axis A of the lens group 101 by fitting the diameter fitting portion 104b provided on the guide member 104 and the diameter fitting portion 105b provided on the cam member 105. It is rotatably supported. A bayonet portion 104c for movably supporting the cam member 105 in the optical axis A direction of the lens group 101 is provided on the outer peripheral surface of the right end portion of FIG. 2 of the guide member 104.

The bayonet portion 104c provided on the guide member 104 engages with the groove 105c formed on the circumference of the diameter fitting portion 105b of the cam member 105, so that the cam member 105 has an optical axis A with respect to the guide member 104. It is supported at a fixed position in the direction. By fixing, for example, an image pickup element (not shown) to the right end portion 104d of FIG. 2 of the guide member 104, it functions as a lens barrel.

FIG. 3 is a perspective view of the lens barrel. As shown in FIG. 3, the cam follower 103 engages with the cam groove 105a of the cam member 105 and also engages with the first groove portion 104a of the guide member 104. The cam groove 105a and the first groove portion 104a each have a minute backlash having substantially the same dimensions as the cam follower 103 in the groove width direction, or the cam follower 103 is press-fitted through a minute gap to hold the cam follower 103 slidably. ..

As a result, the cam follower 103 can move forward and backward in the optical axis A direction by rotating the cam member 105 around the optical axis A of the lens group 101. Further, as will be described in detail later, as shown in FIG. 2, the cam follower 103 is held integrally with the lens group holding member 102, so that the lens group 101 can move forward and backward in the optical axis A direction.

FIG. 4 is a perspective view of the lens group holding member 102. As shown in FIG. 4, the lens group holding member 102 has a second groove portion 102a and a third groove portion 102b that engage with the cam follower 103. The second groove portion 102a and the third groove portion 102b are arranged at a plurality of locations in the circumferential direction.

FIG. 5 is an enlarged view of the second groove portion 102a and the third groove portion 102b. As shown in FIG. 5, the second groove portion 102a and the third groove portion 102b are grooves formed in a rectangular shape and extending with a constant width to engage with the cam follower 103, respectively. The third groove 102b is formed at the bottom of the second groove 102a, and an insertion hole 102c into which the nut member 107 is inserted is formed at the bottom of the third groove 102a. The second groove 102a and the third groove 102b are extended in a direction intersecting each other in FIG. 5, and in the present embodiment, the second groove 102a is extended long in the optical axis direction, and the third groove 102b is extended. Is elongated in the circumferential direction and intersects in a direction substantially orthogonal to each other.

FIG. 6 is a perspective view of the cam follower 103. As shown in FIG. 6, the cam follower 103 has a substantially cylindrical shape in which a through hole 103e is formed in a central portion, and the first cylindrical portion 103a, the second cylindrical portion 103b, and the third cylindrical portion 103c. And has a fourth cylindrical portion 103d. In the present embodiment, the fourth cylindrical portion 103d, the first cylindrical portion 103a, and the second cylindrical portion 103b are coaxially arranged in this order, and the third cylindrical portion 103c is relative to the central axis of the second cylindrical portion 103b. It is eccentrically arranged and arranged in the region of the end face of the second cylindrical portion 103b. The fourth cylindrical portion 103d, the first cylindrical portion 103a, and the second cylindrical portion 103b all have the same diameter in the present embodiment, but may have different diameters.

FIG. 7 is a cross-sectional view showing a state in which the cam follower 103 is engaged with each member and fixed to the lens group holding member 102. As shown in FIG. 7, the first cylindrical portion 103a of the cam follower 103 engages with the first groove portion 104a of the guide member 104, and the second cylindrical portion 103b with the second groove portion 102a of the lens group holding member 102. Engage. Further, the third cylindrical portion 103c engages with the third groove portion 102b of the lens group holding member 102, and the fourth cylindrical portion 103d engages with the cam groove 105a of the cam member 105.

Further, the through hole 103e of the cam follower 103 penetrates in the direction of the axis B orthogonal to the optical axis A, and a stepped surface with which the head of the fastening member 106 abuts is formed in the third cylindrical portion 103c. The fastening member 106 is inserted into the through hole 103e from the outside, the head abuts on the stepped surface in the third cylindrical portion 103c, the threaded portion protrudes from the through hole 103e, and this protruding portion is inserted into the insertion hole 102c. It is screwed and fastened to the nut member 107.

As a result, the end surface 103f of the third cylindrical portion 103c of the cam follower 103 comes into contact with the stepped surface between the third groove portion 102b and the insertion hole 102c, and the cam follower 103 is the lens group holding member 102 by the fastening member 106 and the nut member 107. It is narrowed and held against. In the present embodiment, the cam follower 103 is inserted through the cam groove 105a from the outside, and the cam follower 103 is inserted by arranging the third cylindrical portion 103c close to the optical axis A on the inner diameter side of the second cylindrical portion 103b. It is possible to insert without resistance when doing.

As described above, the fourth cylindrical portion 103d of the cam follower 103 is slidably held with respect to the cam groove 105a, and the first cylindrical portion 103a is slidably held with respect to the first groove portion 104a. .. The first groove portion 104a is configured as a groove having a constant width extending in parallel with the optical axis A, whereby the cam follower 103 moves in the optical axis A direction when the cam member 105 is rotated around the optical axis A. It becomes possible to do. Further, since the cam follower 103 is narrowly held and held with respect to the lens group holding member 102, when the cam member 105 rotates, it is integrally driven with the lens group holding member 102 in the optical axis A direction.

Further, the second groove portion 102a with which the second cylindrical portion 103b of the cam follower 103 engages is a groove having a constant width extending in the optical axis A direction. In the present embodiment, the cam follower 103 and the groove portions 102a and 102b are arranged at three locations at substantially equal intervals in the circumferential direction. The second groove portion 102a and the second cylindrical portion 103b are engaged with each other, and the cam follower 103 is narrowly held by the lens group holding member 102, so that the integrated cam follower 103 and the lens group holding member 102 are in the axis B direction. It is constrained with a degree of freedom only in the rotation direction around the axis B. Further, by arranging the cam follower 103 and the groove portions 102a and 102b at a plurality of locations in a circumferential shape around the optical axis A, the lens group holding member 102 rotates in a plane orthogonal to the optical axis A and around the axis B. Is also restrained.

At the outer end of the cam follower 103, a slit portion (engagement portion) 103 g formed radially with respect to the shaft B is formed. The cam follower 103 can be rotated around the shaft B by engaging a tool such as a screwdriver with the slit portion 103g. The cam follower 103 can reduce the frictional force on the contact surface 103f and the contact surface with the fastening member 106 by using a material having excellent slidability such as polyacetal resin. This makes it possible to easily rotate the cam follower 103 around the axis B with a tool such as a screwdriver.

As described above, since the first cylindrical portion 103a, the second cylindrical portion 103b, and the fourth cylindrical portion 103d of the cam follower 103 are arranged coaxially with each other, the cam follower 103 is rotated around the axis B. However, the position with the cam member 105 and the guide member 104 does not change. However, since the third cylindrical portion 103c rotates about the axis C eccentric with respect to the second cylindrical portion 103b, by rotating the cam follower 103, the third cylindrical portion 103c rotates eccentrically by the distance between the shaft C and the shaft B.

The third cylindrical portion 103c and the third groove portion 102b are engaged with each other, and the third groove portion 102b has a certain width in a direction intersecting with the second groove portion 102a and extends. The third groove portion 102b and the third cylindrical portion 103c engage with each other with a minute backlash or a press-fitting amount through a minute gap. As described above, when the cam follower 103 rotates around the axis B, the third cylindrical portion 103c rotates eccentrically with respect to the axis B, and the lens group holding member 102 engaged with the third cylindrical portion 103c is the cam follower 103. It moves in the optical axis direction at the position where it comes into contact with.

8 and 9 are cross-sectional views at a position where the cam follower 103 rotates around the axis B and the third cylindrical portion 103c is most displaced in the optical axis A direction, respectively. As shown in FIGS. 8 and 9, the lens group holding member 102 is freely displaced in the optical axis A direction (arrow direction in the figure) in the phase of the third cylindrical portion of the cam follower 103. It is possible to change the inclination of. Similarly, by arranging a plurality of cam followers 103 in the circumferential direction of the lens group holding member 102, the lens group 101 can be freely tilted.

FIG. 10 schematically shows the positional relationship between the rotation amount of the cam follower 103 when the cam follower 103 is rotated and the second cylindrical portion 103b, the third cylindrical portion 103c, the second groove portion 102a, and the third groove portion 102b. It is a figure which shows. In FIG. 10, the rotation amount of the cam follower 103 is such that the position of FIG. 7 is the rotation amount of 0 degrees. As shown in FIG. 10, it can be seen that by rotating the cam follower 103, the lens group holding member 102 held by the cam follower 103 can be freely tilted.

By the way, the lens group 101 constitutes a photographing optical system together with other lens groups (not shown). In general, it is impossible to hold each lens group of an optical system in a geometrically ideal position because of the accuracy tolerance of the member that holds the lens group. Therefore, in order to improve the performance of the optical system, the alignment of the lens group is adjusted with the lens group and the member for holding the lens group incorporated.

As in Patent Document 1, it is also possible to tilt the lens group holding member by engaging a cam follower having a cylindrical portion eccentric with the cam groove and rotating the cam follower. However, the cam groove is generally a groove having an inclination with a different lead angle depending on the region. For example, as the regions 105d and 105e in the cam groove 105a in FIG. 3, regions having different inclination angles are generally mixed.

Here, it is assumed that the lens group is adjusted by rotating a cam follower having a cylindrical portion eccentric to the region 105d in FIG. 3, for example. Even if the amount of tilt of the lens group is appropriately adjusted so that the optical performance is good in this region 105d, the contact point of the cylindrical portion of the cam follower that engages with the cam groove due to the movement of the cam follower to the region 105e is a region. It is different from the contact point of the cylindrical portion in 105d.

As a result, even if the cam follower is rotated to adjust the lens group to tilt at the position of the region 105d and the lens group holding member is displaced to a certain displacement amount, the region changes and the advance angle of the cam groove changes, so that the lens group changes. The amount of displacement of the holding member will be different. The amount of tilting of the lens group changes due to the change in the amount of displacement of the lens group holding member, which causes deterioration of optical performance.

On the other hand, in the present embodiment, the first cylindrical portion 103a and the fourth cylindrical portion 103d are coaxially arranged even in the cam groove 105a whose inclination angle differs depending on the region of the rotation angle of the cam member 105. Therefore, even if the cam follower 103 is rotated to displace the lens group holding member 102 to a certain displacement amount and the cam follower 103 is tilted and adjusted so that the optical performance is good, the lens group is formed by the region in the cam groove 105a where the cam follower 103 stops. The displacement amount of the holding member 102 does not differ. That is, it is possible to keep the amount of tilt of the lens group 101 constant regardless of the regions of the cam grooves 105a having different inclination angles (advance angles).

As described above, in the present embodiment, in the entire operating range of the cam groove (cam portion) 105a of the cam member 105, the lens group 101 is highly accurate without changing the tilt amount of the lens group 101 by a simple configuration. Can be retained.

The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, etc. can be appropriately changed as long as the gist of the present invention is not deviated. Is.

101 Lens group 102 Lens group holding member 102a Second groove 102b Third groove 103 Cam follower 103a First cylinder 103b Second cylinder 103c Third cylinder 103d Fourth cylinder 104 Guide member 104a First Groove 105 Cam member 105a Cam groove

Claims (11)

A lens holding member that holds the lens and
A cam follower that supports the lens holding member and
A guide member in which a first groove with which the cam follower engages is provided so as to extend in the direction of the optical axis of the lens and guides the lens holding member in the direction of the optical axis.
A cam member with which the cam follower is engaged and a cam groove whose advance angle changes according to a rotation angle is provided and rotates to move the lens holding member in the direction of the optical axis is provided.
The cam follower has a first cylindrical portion, a second cylindrical portion and a fourth cylindrical portion arranged coaxially with each other, and a third cylindrical portion eccentrically arranged with respect to the second cylindrical portion. Have and
The first cylindrical portion engages with the first groove portion of the guide member, the second cylindrical portion engages with the second groove portion provided on the lens holding member, and the third cylindrical portion engages with the third groove portion. The cylindrical portion of the lens is engaged with a third groove portion provided in the lens holding member and extended in a direction intersecting the second groove portion, and the fourth cylindrical portion is the cam member. A lens barrel characterized by engaging with a cam groove. The third cylindrical portion is arranged closer to the optical axis than the second cylindrical portion, and is located on the second cylindrical portion within the region of the end surface of the second cylindrical portion parallel to the optical axis. The lens barrel according to claim 1, wherein the lens barrel is eccentrically arranged. The cam follower has a hole penetrating in a direction orthogonal to the optical axis, and by screwing the screw portion of the fastening member inserted into the hole into the nut member, the cam follower is narrowed by the fastening member and the nut member. The lens barrel according to claim 1 or 2 , wherein the lens holding member is supported in a closed state. The lens barrel according to any one of claims 1 to 3 , wherein the cam follower is provided with an engaging portion with which a tool for rotating the cam follower is engaged. The lens barrel according to claim 4 , wherein the engaging portion is a slit portion radially provided at a plurality of locations on the outer end surface of the cam follower in the axial direction. The lens barrel according to any one of claims 1 to 5 , wherein the cam follower is made of a polyacetal resin. The lens barrel according to any one of claims 1 to 6 , wherein the cam followers are arranged at a plurality of locations in the circumferential direction of the lens holding member. One of claims 1 to 7 , wherein the second groove portion is extended in the direction of the optical axis, and the third groove portion is extended in the circumferential direction of the lens holding member. The lens barrel described in. The lens barrel according to claim 8 , wherein the second groove portion and the third groove portion intersect each other in a direction orthogonal to the optical axis. The lens barrel according to any one of claims 1 to 9 , wherein the guide member is arranged on the outside of the lens holding member, and the cam member is arranged on the outside of the guide member. An optical device comprising the lens barrel according to any one of claims 1 to 10 .

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