JP2741239B2 - Zoom lens barrel - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in copper zoom lens mirrors, in particular, zoom lens copper mirrors suitable for use in compact cameras.

[Conventional technology]

Conventionally, mechanically compensated zoom lens mirror copper, which mechanically changes the position of each lens group constituting a zoom lens system to adjust the magnification and focal position, has a rotating cam with cam grooves having different moving characteristics. In many cases, each lens group is moved using a cylinder (hereinafter referred to as a cam cylinder method). This is because the cam cylinder method has the advantage that the movement characteristics of the lens group can be freely given to the cam groove and nonlinear movement can be realized.

[Problems to be solved by the invention]

However, when the lens group is driven by the above-described conventional cam cylinder method, there are various problems as described below.

Cam grooves originally require high precision machining,
A cam groove for a lens group that moves nonlinearly requires more precise processing than a beam. Therefore, when the cam cylinder is manufactured by machining such as cutting, it is inevitable that the machining time is prolonged and the cost is increased.

The wall surface (working surface) of the cam groove which is in sliding contact with the cam pin is configured to include a normal line to the photographing optical axis. When a cylinder is manufactured, the wall surface becomes an undercut portion for the core, and the mold configuration becomes complicated.

Since the cam barrel is arranged outside the lens frame, the outer diameter of the mirror copper becomes large, which may cause the camera body to become large.

In addition to the difficulties in the design and manufacturing techniques, the conventional zoom lens mirror copper of the cam cylinder type is disadvantageous in terms of functions such as collapsing and macro photography.

That is, with respect to the retracting function, in the case of a two-unit type zoom lens, zooming is realized by relative movement of the two lens units on the optical axis. Because the lens group that moves the most in the lens system is restricted, the cam groove that engages with the front lens group is extended toward the camera body, and the cam groove that engages with the rear lens group is also the front lens. They had to be extended to avoid interference with groups and surrounding members. Longer cam grooves not only increase processing complexity and cost, but also reduce the strength of the cam cylinder and the resulting accuracy, and increase the thickness of the cam cylinder to improve strength. Doing so will lead to larger copper mirrors.

There is a problem that.

On the other hand, regarding the macro shooting function, a cam groove for macro shooting is formed following the cam groove for zooming formed on the cam cylinder (Japanese Patent Publication No. 51-17045).
No.), the overall length of the cam groove becomes too long, and the accuracy may be reduced.

The one in which a plurality of lens groups are moved by separate cam cylinders (Japanese Patent Publication No. 55-10885) has a certain margin for fitting between the cam cylinders in order to make the operation of each cam cylinder smooth. Must be performed, the operation is unstable, and blurring tends to occur.

There was such a problem.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a zoom lens mirror copper capable of achieving high-precision linear and non-linear movement of each lens group by a moving mechanism having high strength and easy plastic molding.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a zoom lens copper having a zoom lens system having a linear lens group linearly moving on a photographing optical axis and a non-linear lens group moving nonlinearly, which can be driven from the camera body side. A pin that accommodates the linear lens group in a first lens frame in a zooming cylinder that engages with one helicoid cylinder and that fits into a correction cam groove inside the first helicoid cylinder through an arc hole of the zooming cylinder. The non-linear lens group is housed in a second lens frame which is engaged with a second helicoid cylinder rotatable in a zooming cylinder via a lens, and a linear component of the moving characteristic of each lens group is nonlinearly adjusted by a helicoid screw. The components are configured to be carried by the correction cam grooves, respectively.

〔Example〕

Hereinafter, the present invention will be described with reference to the accompanying drawings, taking a zoom lens mirror copper composed of a two-unit type zoom optical system as an embodiment.

FIG. 1 is a cross-sectional view showing an example of the zoom lens mirror copper of the present application, in which the upper half shows a 1/4 cross section when set to the short focus position, and the lower half shows 1 / cross section when set to the long focus position. 4 sections are shown. FIG. 2 is a schematic plan view of a correction cam groove formed on the inner periphery of the first helicoid cylinder, FIG.
(B) is a partial cross-sectional view of the zooming cylinder in FIG. 1, FIG. 4 is an explanatory view showing the relative arrangement change of the correction cam groove, the arc hole, and the pin accompanying the zooming, and FIG. 5 is an extension groove for collapsing. FIG. 6 is a schematic plan view of the corrected cam groove and the arc hole, FIG. 6 is an explanatory view showing the relationship between the corrected cam groove and the arc hole at the time of collapsing, and FIG. 7 is a schematic of the correction cam groove formed with an extended groove for macro photography. Plan view,
FIG. 8 is an explanatory view showing the relationship between the correction cam groove and the arc hole at the time of collapsing.

In the drawing, reference numeral 1 denotes a zoom lens mirror copper according to the present invention. The zoom lens mirror copper 1 moves on the optical axis O, and changes the relative position of each other to adjust the magnification and focus before and after the front lens group G ₁ and the rear lens group G _1. and a zoom optical system Z 2 groups form a lens group G ₂ Prefecture. The right end of the fixed body 2 of the zoom lens mirror copper 1 is fixed to the body B of the camera body. During front lens group G ₁ of the zoom optical system Z is during zooming, as a linear lens unit which moves based on the unique linear characteristic diagram, the rear lens group G ₂ is that the movement of the front lens group G _1, unique as a nonlinear lens unit which moves a predetermined range while changing the relative distance to the previous lens group G ₁ in accordance with a nonlinear characteristic diagram are configured respectively.

Reference numeral 3 denotes a first helicoid cylinder. The helicoid cylinder 3 is rotatably fitted to the inside of the fixed barrel 2, and has a straight movement preventing ring 4 fixed to the fixed barrel 2 on a part of its outer peripheral surface. Is formed so that it cannot move in the optical axis O direction. In the vicinity of the rear end of the outer peripheral surface of the first helicoid cylinder 3, there is provided a tooth portion 3b that meshes with a gear 5 of a driving means (for example, a motor, not shown) on the camera body side. It is configured to be rotated by the gear 5. Although the formation area of the tooth portion 3b is appropriate, in the illustrated embodiment,
It is formed over a range of 0 degrees.

Reference numeral 6 denotes a correction cam groove. The correction cam groove 6 is formed on the inner peripheral surface of the first helicoid cylinder 3 together with a female screw 3c. Here, the lead of the female screw 3c is determined according to the linear transfer characteristics of the front lens group G _1.

The correction cam groove 6 is for accelerating and decelerating the linear movement of the rear lens group G position ₂ as described later, and has a shape extending in the optical axis direction while slightly meandering in a direction orthogonal to the optical axis O. It consists of a long groove (Fig. 2). Therefore, when the first helicoid cylinder 3 is injection-molded integrally with the correction cam groove 6 using a light-shielding hard synthetic resin material, the correction cam groove 6 has a small amount of displacement from the optical axis O direction. The core forming the groove 6 has a relatively simple shape and can be extracted in a direction substantially orthogonal to the optical axis O. Here, the meandering amount of the correction cam groove 6 (the amount of displacement in the direction orthogonal to the optical axis O) is
Decreasing the second helicoid cylinder 16 to be described later via Hayashi, corresponds to the ray-shaped moving amount of the rear lens group G ₂ (shift amount excluding linear component in the movement characteristics).

7 is a zooming tube, the zooming tube 7, the first lens frame 9 which holds the front lens group G ₁ in the front is fixedly provided. A male screw 7a which engages with the female screw 3c of the first helicoid is provided on the outer periphery of the rear portion of the zooming cylinder 7, and the guide rod 8 of the first linear guide member 8 is slidably mounted in the side wall. Since the key groove 7c to be fitted is formed, when the first helicoid cylinder 3 rotates, the zooming cylinder 7 moves forward and backward in the direction of the optical axis O by the engagement action of the two screws.
In the area where the male screw 7a of the zooming cylinder 7 is formed, the radiation opening angle θ is set in a direction (circumferential direction) perpendicular to the optical axis O.
Arc holes 7b are formed (FIG. 3 (a),
(B)). The arc-shaped hole 7b is for allowing the pin 17 that penetrates the zooming cylinder 7 and fits into the correction cam groove 6 to be rotated in a direction orthogonal to the optical axis O.

The first rectilinear guide member 8 is formed of an L-shaped rod-shaped member, the bent end of which is fixed to the fixed barrel 2 in a cantilever manner by a screw N, and the guide rod 8a as a free end is parallel to the optical axis O. The zooming cylinder 7 is set so as to pass through the keyway 7c.

The first lens frame 9 is made of, for example, a light-shielding synthetic resin material, and is connected to the inside of the distal end portion of the zooming cylinder 7 by appropriate means. Then, the interval setting members 10 and 11
It holds the lenses of the front lens group G ₁ on the optical axis O through the lens suppressed rear flange portion 9a of the lenses in ring 12
It is configured so as to be pressed and fixed. Reference numeral 9b denotes a locking projection for locking the lens holding ring 12. Lens holder ring 12
Is made of a light-shielding synthetic resin material, and an engagement hole 12a formed in a peripheral wall of the lock protrusion 9b is formed by the elasticity of the synthetic resin material.
The locked, has a front lens group G ₁ to hold while pressing.

Or primarily a part related to the movement of the front lens group G _1. Hereinafter, describing the part related to the movement of the rear lens group G _2.

A second helicoid cylinder 16 is rotatably fitted to the inner peripheral surface at the rear end of the zooming cylinder 7.

The second helicoid cylinder 16 has a female screw 16a having a required lead on the inner peripheral surface thereof, and the pin 17
Has been planted. The engagement pin 17 is for transmitting a rotational force for moving the second lens frame 18 along the optical axis O, and penetrates through the arc-shaped hole 7b of the zooming cylinder 7 as described above. The first helicoid cylinder 3 is configured to engage with the correction cam groove 6. For this reason, the second helicoid cylinder 16 is connected to the optical axis O via the pin 17 engaging with the correction cam groove 6.
Can be rotated within the range of the radiation opening angle θ of the arc hole 7b in the rotation direction around the center, but cannot move in the direction of the optical axis O (FIG. 3).

The second lens frame 18, the lens that is screwed into the female thread 16a of the second helicoid cylinder 16 on the outer peripheral surface with an external thread 18a, constituting the rear lens group G ₂ via the space setting members 19, 20 Holding. The second lens frame 18, pressing each lens in the front end flange 18b by the lens suppressing ring 21 is screwed into the open end of the other hand, securing each lens in the rear lens group G _2.

In the large-diameter portion of the second lens frame 18 on which the male screw 18a is formed, a key groove 18c through which the guide rod 22a of the second rectilinear guide member 22 is inserted is formed similarly to the above-described zooming cylinder 7. .

The second straight guide member 22 is, like the first straight guide member 8, one end of the zooming cylinder 7 cantilevered by appropriate means.
And a guide portion 22a, which is a free end, is provided in the key groove 18c so as to be parallel to the optical axis O.

Hereinafter, the zooming operation of the zoom lens mirror copper 1 will be described.

First, the gear 5 of the driving means on the camera body side is rotated,
The first helicoid cylinder 3 is rotated. In this case, if the zoom lens Kyodo 1 that are configured as a short focal length, as indicated by the 1/4 cross section of the upper half of FIG. 1, the relative distance between the front lens group G ₁ and the rear lens group G ₂ Is greatly open. Here, the correction cam groove 6 of the first helicoid cylinder 3 and the arc hole of the zooming cylinder 7
The relative positional relationship between 7b and the engaging pin 17 is as shown in FIG. 4 (a).

In this state, when the gear 5 is rotationally driven in a direction for realizing a long focal length of the zoom lens system, the rotational driving force is transmitted to the first helicoid cylinder 3 via the tooth portion 3b, and the first helicoid cylinder 3 is driven. Rotate in a predetermined direction.

The rotation movement of the first helicoid cylinder 3 is transmitted to the male screw 7a on the zooming cylinder 7 side via the female screw 3c, but the zoom rod 7 is inserted into the keyway 7c by the guide rod 8a of the first rectilinear guide member 8. As a result, the zooming cylinder 7 is driven straight forward along the optical axis O.

As a result, the zooming cylinder 7 moves forward on the optical axis in accordance with the lead of the female screw 3c determined according to the unique linear movement characteristic, so that the first lens frame integrally connected to the zooming cylinder 7 is formed. front lens group G ₁ in 9 simultaneously, it is possible to realize a unique linear movement.

On the other hand, since the second helicoid cylinder 16 is linked via the pin 17 penetrating through the arc hole 7b of the zoom cylinder 7, it moves linearly in the direction of the optical axis O integrally with the zoom cylinder 7.

However, at this time, the head of the pin 17 is fitted in the correction cam groove 6 of the first helicoid cylinder 3, and the second helicoid cylinder 16
As the zooming cylinder 7 moves, it rotates with the first helicoid cylinder 3 while linearly moving on the optical axis together with the zooming cylinder 7, and is further rotated in the direction perpendicular to the optical axis O in accordance with the meandering amount of the correction cam groove 6.

That is, when the second helicoid cylinder 16 rotates, a linear movement corresponding to the lead of the female screw 16a of the second helicoid cylinder 16 is performed in the zooming cylinder 7, and the linear movement is further increased / decreased by the correction cam groove 6. Minutes are added. As a result,
Lens group G ₂ rear and the second lens frame 18 which is prevented from rotating by the second linear guide member 22 along the optical axis O, relative to the camera body side, (a first helicoid cylinder) + (second helicoid The inherent non-linear movement consisting of the sum of the drive mechanisms of (cylinder) + (correction cam groove) is realized.

Here, if the rotation of the first helicoid cylinder 3 is stopped at an intermediate photographing magnification, the three members of the correction cam groove 6, the arc hole 7b, and the engagement pin 17 become as shown in FIG. It will stop due to the relative positional relationship.

Similarly, when the rotation of the first helicoid cylinder 3 is stopped while the maximum photographing magnification is obtained, the correction cam groove 6 and the arc hole
7b and three parties of the engaging pin 17 is set by the arrangement of these three such stop a relative positional relationship, the relative relationship of the rear lens G ₂ and the front lens group G ₁ as of FIG. 4 (c) .

The combination of the two helicoid means and the correction cam groove as described above, the linear movement and the rear lens group of the front lens group G ₁
To achieve non-linear movement of the G _2, but the following description will discuss Examples that impart collapsed function or macro photography function by appropriately changing the configuration of the correction cam groove.

First, the zoom lens mirror copper 1 is configured so that the mirror copper length becomes shortest when set to the short focal length state. As described above, the front lens group G ₁ and the rear lens group G ₂ has a slightly larger spacing. Therefore, if the distance between the two can be reduced in the short focal length state, the mirror copper 1 can be shortened accordingly.

However, in the configuration as shown in FIG. 1, if the front lens group holding frame 9 is to be moved further rightward from its shortest focal length, the rear lens group holding frame 18 is also moved rightward together with the camera body. A collision may occur with a member on the side (particularly not shown).

Therefore, the second embodiment of the invention, as shown in FIG. 5 (a), to extend the collapsing cam groove to the end of the correction cam grooves 6, the lens group G ₁ before the camera body it is moved, the rear lens group G ₂ is obtained by configured to be relatively stopped.

That is, an axial play groove 31 having the same direction and the same inclination angle with respect to the lead angle of the male screw 7a of the first helicoid is formed as an extension at one end of the arc hole 7b of the zooming cylinder 7 on the short focal length side, A circumferential play groove 32 extending in a direction perpendicular to the optical axis O is formed at one end on the short focal length side of the correction cam groove 6 (FIG. (B)). In this configuration, even when the first helicoid cylinder 3 is rotated during the collapse, the head of the engaging pin 17 is moved from the area of the arc hole 7b to the circumferential play groove 32 of the correction cam groove 6 in the initial stage. Therefore, the movement of the engagement pin 17 in the optical axis direction is absorbed by the circumferential play groove 32 even in the subsequent rotation operation.

That is, when the first helicoid cylinder 3 is rotated to cause the zooming cylinder 7 to move rightward from the short focal length normal position to the right, the engagement pin 17 restricted from moving in the optical axis direction.
Is an axial play groove from one end of the arc hole 7b of the zooming cylinder 7.
Guided into 31. Then, the engaging pin 17 is
In response to the rotation operation of the helicoid cylinder 3, the helicoid cylinder 3 apparently moves toward the subject along the inclination angle of the axial play groove 31. Therefore, as shown in FIG. 6, the engaging pin 17 moves in the opposite direction (subject side) at the same speed with respect to the rightward movement of the zooming cylinder 7, and relatively stops.

Note that the engagement pin 17 inserted into the circumferential play groove 32 is
Does not receive the rotation transmitting force from the correction cam groove 6 even if the first helicoid cylinder 3 rotates, and the second helicoid cylinder 16 is also kept stationary.

Next, the seventh embodiment in which the macro shooting function is provided
And FIG.

To achieve macro photographing zoom lens Kyodo 1 as first shown, the entire zoom lens optical system in a state of being set to a long focal length, on the axis of the front lens group G ₁ and the rear lens group G ₂ What is necessary is just to move the whole to the subject side while keeping the interval constant.

In this case, in order to move the entire optical system forward beyond the normal position with the longest focal length, the first helicoid cylinder 3 must be rotated to move the zooming cylinder 7 further forward.

However, when the first helicoid cylinder 3 is rotated, the rotational force is transmitted to the second helicoid cylinder 16 connected to the correction cam groove 6 via the engagement pin 17, and the front lens group of the first lens frame 9 is rotated. G ₁ and the relative distance between the lens group G ₂ after the second lens frame 18 is changed.

Therefore, in this embodiment, in order to prevent such a change in the relative spacing, an axial extension groove 33 that is inclined at the front end (end on the long focal length side) of the correction cam groove 6 is formed. The axial extension groove 33 is formed so as to extend in the same direction and the same inclination angle as the thread of the female screw 3c of the first helicoid, and engages as the zooming cylinder 7 moves even if the first helicoid cylinder 3 rotates. The configuration is such that the pin 17 enters the axially extending groove 33 and the rotational transmission force from the correction cam groove 6 is not transmitted to the engagement pin 17 (that is, the second lens frame 18).

Therefore, when the zooming cylinder 7 is at the normal position of the long focal length, as shown in FIG. 8A, the engagement pin 17 engaged with the correction cam groove 6 is moved to the first helicoid during macro photography. When the cylinder 3 is rotated, the circular arc hole 7b is pushed forward by the end on the long focal length side and is moved forward together with the zooming cylinder 7, so that the rotation amount of the first helicoid cylinder 3 increases and As shown in FIG. B), the rod enters the on-axis extension groove 33 to maintain a regular position on the optical axis. As a result, the first lens group 9 and the second lens frame 18 of the zooming cylinder 7 move on the axis without causing a response movement, thereby enabling macro photography.

Reference numeral 13 denotes a protection filter frame provided at the forefront of the zooming cylinder 7. The protection filter frame 13 holds, for example, an ultraviolet cut filter F. Further, 14 is a diaphragm and shutter device, as the aperture and shutter blade in the apparatus 14 is located behind a predetermined position of the front lens group G _1, is attached. The drive mechanism of the aperture / shutter device 14 is omitted, but is constituted by an appropriate combination of known techniques, including those in which the aperture device and the shutter device are mechanically separated.

As described above, the present invention has been described based on a plurality of embodiments.
The present invention is not limited to these, and various modifications can be made without departing from the scope of the invention. For example, in the illustrated embodiment, a so-called two-group zoom mirror copper has been described. The present invention can also be applied to a type of mirror copper for a zoom lens.

〔The invention's effect〕

As described above, the present invention provides a first helicoid cylinder that can be driven from the camera body side in a zoom lens mirror copper provided with a zoom lens system having a linear lens group that linearly moves on the photographing optical axis and a nonlinear lens group that moves nonlinearly. The linear lens group is housed in a first lens frame in a zooming cylinder that engages with the first lens frame, and the first lens frame is inserted through an arc hole of the zooming cylinder.
The non-linear lens group is housed in a second lens frame which engages with a second helicoid cylinder rotatable in the zooming cylinder via a pin fitted into a correction cam groove inside the helicoid cylinder. In addition, linear and non-linear lens movement can be realized with high accuracy by means of lens movement means that is easy to mold plastic.

In addition, the first helicoid cylinder, which is a main part of these lens moving members, and the correction cam groove can be integrally formed.
For this reason, an excellent effect of providing a lightweight, inexpensive and highly accurate zoom lens mirror copper, which is ideal for a compact camera, is provided.

Further, by extending the retractable cam groove at the short focal length side end of the correction cam groove, the retractable function can be provided without inducing the strength of the lens moving means and increasing the diameter thereof. Make a great contribution to

Furthermore, by extending the macro photographing cam groove at the long focal point end of the correction cam groove, a macro photographing function can be provided in addition to the zooming function. is there.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of the zoom lens mirror copper of the present application, in which the upper half shows a 1/4 cross section when set to the short focus position, and the lower half shows 1 / cross section when set to the long focus position. 4 sections are shown. FIG. 2 is a schematic plan view of a correction cam groove formed on the inner periphery of the first helicoid cylinder, FIG.
(B) is a partial cross-sectional view of the zooming cylinder in FIG. 1, FIG. 4 is an explanatory view showing the relative arrangement change of the correction cam groove, the arc hole, and the pin accompanying the zooming, and FIG. 5 is an extension groove for collapsing. FIG. 6 is a schematic plan view of the corrected cam groove and the arc hole, FIG. 6 is an explanatory view showing the relationship between the corrected cam groove and the arc hole at the time of collapsing, and FIG. 7 is a schematic of the correction cam groove formed with an extended groove for macro photography. Plan view,
FIG. 8 is an explanatory view showing the relationship between the correction cam groove and the arc hole at the time of collapsing. B: camera body O: photographing optical axis G _1: front lens group G _2: rear lens group F: ultraviolet cut filter Z: zoom optical system 1: zoom lens mirror copper 2: fixed barrel 3 ... First helicoid cylinder 3a... Flange groove 3b... Teeth 3c... First helicoid female screw 4. ...... Male screw of first helicoid 7b ... Arc hole 7c ... Keyway 8 ... First linear guide member 8a ... Guide rod 9 ... First lens frame 9a ... Rear end flange 9b ... Locking projection 10, 11, 19 Interval setting member 12 Lens holding ring 12a Engagement hole 13 Protective filter frame 14 Aperture and shutter device 16 Second helicoid cylinder 16a Female second helicoid Screw 17 Pin 18 Second lens frame 18a Male screw of second helicoid 20 Interval setting member 21 Lens holding part Material 22: second linear guide member 22a: guide rod 31: axial play groove 32: circumferential play groove 33: axial extension groove

Claims (4)

(57) [Claims] 1. A zoom lens copper having a zoom lens system having a linear lens group that linearly moves on a photographing optical axis and a nonlinear lens group that moves nonlinearly, engages with a first helicoid cylinder that can be driven from the camera body side. The linear lens group is housed in the first lens frame in the zooming cylinder, and the pin is inserted into the correction cam groove inside the first helicoid cylinder through the arc hole of the zooming cylinder. A zoom lens mirror copper, wherein the non-linear lens group is housed in a second lens frame that engages with a second helicoid cylinder that is rotatable. 2. The zoom lens mirror copper according to claim 1, wherein said first helicoid cylinder and said correction cam groove are integrally formed. 3. The zoom lens mirror copper according to claim 1, wherein a retractable cam groove extends from a short focal length side end of said correction cam groove. 4. The zoom lens according to claim 1, wherein a macro imaging cam groove is extended at a long focal length end of said correction cam groove. Mirror copper.