JP3194113B2 - Lens moving device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera for photographing,
The present invention relates to a lens moving device used for an optical device such as a miniature photographing machine, a video camera, a copying machine, and a enlarger.

[0002]

2. Description of the Related Art Optical devices such as cameras have been miniaturized.
Recently, in addition to a single focus lens having about three to four lenses, an optical apparatus equipped with a zoom lens has been increasing.

[0003] For example, a zoom lens having a plurality of lens groups has a cam frame having an elongated cam hole extending along the periphery thereof and a cam follower protruding into the cam hole. In many cases, a plurality of moving frames supporting the lens group are provided. During zooming, the cam frame is rotated to move each moving frame, and the lens group is displaced in the optical axis direction to change the magnification.

[0004]

The conventional zoom lens as described above has a large lens barrel diameter because the lens barrel has a superimposed structure of a cam frame and each moving frame, thereby reducing the size of a camera or the like. Was an important issue in doing so.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to develop a lens moving device capable of miniaturizing an optical device such as a camera when moving a zoom lens or a single focus lens.

[0006]

In order to achieve the above-mentioned object, according to the present invention, a cylindrical fixed frame having an inner peripheral surface formed by screwing is provided, and a moving frame for holding a lens is moved in a cylindrical axial direction of the fixed frame. The fixed frame is mounted inside the fixed frame so that it can move forward and backward without rotating, and is formed to have the same diameter as the moving frame.
Screw the interlocking machine the outer periphery is screwed into the screw of the fixed frame
A gear that is rotationally driven by a frame, and a drive ring that is rotationally driven to move and move in the cylindrical axis direction of the fixed frame ,
On the other hand, the one side engaged with the drive ring, given the other side in the moving frame of the moving force of the drive ring by fastened to the movable frame
And obtain coupling member, giving a spring force to the connecting member, the connecting
Connect the drive ring through the connecting member in the cylindrical axis direction of the fixed frame.
Press and mechanically loosen the screw engagement between the drive ring and the fixed frame.
And a spring member that absorbs the movement of the lens and a moving frame that holds the lens by rotating and driving the drive ring.

[0007]

In this lens moving device, the driving frame is rotatably driven by the interlocking mechanism, and is driven to move in the cylindrical axis direction of the fixed frame. The displaced lens is displaced in the optical axis direction.

The drive ring is screwed into a screw formed on the inner peripheral surface of the fixed frame, and is connected to the movable frame by a connecting member receiving the ring moving force, so that the drive ring moves in the optical axis direction. At this time, the moving frame moves forward and backward by being pulled or pushed by the drive ring. The drive ring is connected
Since it is pressed by the spring member through the member,
There is no mechanical play in screwing with the fixed frame, so the moving frame moves forward and backward
The movement is performed with high accuracy.

[0009]

Next, an example in which the present invention is applied to a zoom lens of a camera will be described with reference to the drawings. 1 is a front view of a lens barrel of a zoom lens, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a sectional view taken along line BB in FIG.

In these figures, reference numeral 50 denotes a cylindrical fixing frame, to which a flange 50a provided at the rear end is attached and fixed to a camera body. As shown in FIGS. 1 and 2, a helicoid screw (female) 50 b is provided on the inner surface of the fixed frame 50, and a drive ring 5 provided inside the rear of the fixed frame 50 is provided.
1 is screwed into the helicoid screw 50b.

That is, the drive ring 51 is provided with a helicoid screw (male) 51a around its outer periphery, and this helicoid screw 51a is screwed to the helicoid screw 50b of the fixed frame 50. A gear 51b is engraved on the outer periphery of the front side of the drive ring 51 (the outer periphery on the right end side in FIG. 2), and the gear 51b is driven by an interlocking mechanism described later to rotate.

Reference numeral 52 denotes a first moving frame.
Is a circular frame formed with a slightly smaller diameter than the fixed frame 50, and is movably mounted on the fixed frame 50. The first moving frame 52 has a locking projection 52a as shown in FIG. The locking projections 52a are provided at four positions on the inner surface of the rear end of the first moving frame 52 at equal intervals.

The above-described drive ring 51 and first moving frame 52
Are connected by a friction spring 53 as an interlocking member. As shown in detail in FIG. 4, the friction spring 53 has a shape in which four rising portions 53b are raised at equal intervals from the inner peripheral edge of a ring-shaped flange plate 53a, and each of the rising portions 53b has an engagement hole. 53c is provided. Further, a convex portion 53 as shown in FIG.
d is formed in four places.

The friction spring 53 brings the flange plate 53a into contact with the rear surface of the drive ring 51, and
3b, each locking projection 52 of the first moving frame 52 is inserted into the engagement hole 53c.
The drive ring 51 and the first moving frame 52 are connected by engaging the control ring a. By this connection, the drive ring 51, which rotates and moves in accordance with the helicoid screw, moves the first moving frame 52, which moves without rotation, in the optical axis direction.

At this time, the drive ring 51 rotates while slipping with respect to the flange plate 53a of the friction spring 53 and the first moving frame 52.
The frictional resistance is reduced by the protruding portion 53d formed as shown in FIG.

On the other hand, on the inner surface of the fixed frame 50, key grooves 50c provided linearly in the front-rear direction are respectively provided at equal positions, and each key provided around the rear end of the first movable frame 52. -5
2b is projected into these key grooves 50c. The first moving frame 52 is moved in the optical axis direction (left and right directions in FIG. 2) while the key 52b is guided by the key groove 50c without rotating.
In other words, it is configured to be pushed by the drive ring 51 that rotates in accordance with the helicoid screws 50b and 51a, and to be pulled and moved in the optical axis direction without rotating.

The drive ring 51 is, as described in detail in FIG.
The first motor 54 is driven to rotate by an interlocking mechanism including an output gear 55, a reduction gear 56, a long gear 57, and a moving gear 58. The first motor 54 is a DC motor, which is mounted on a fixed plate 59 provided on the fixed frame 50, and performs pulse control using a photo interrupter 60. Note that 60
a indicates an encoder.

A reduction gear 56 linked to the output gear 55 and a long gear 57 linked to the reduction gear 56 are supported by a fixed frame 50. Further, a moving gear 58 linked to the long gear 57 is supported by a bearing upright portion 52c provided on the first moving frame 52 so that the gear 58 meshes with the gear 51b of the drive ring 51. .

By this interlocking mechanism, the rotational driving force of the first motor 54 is transmitted to the moving gear 58, and the moving gear 58
As a result, the drive ring 51 rotates. Therefore, the drive ring 51 rotates and moves according to the helicoid screws 50b and 51a, and moves the first moving frame 52 in the optical axis direction.
At this time, the moving gear 58 moves along the long gear 57.

The first moving frame 52 has a shutter frame 6
The front group lens 62 is supported by a cylindrical portion 61a of the shutter frame 61, and a shutter blade 63 is provided near the rear surface of the shutter frame 61 together with a shutter blade holder. . Note that this shutter blade 6
Reference numeral 3 denotes a motor driving source 78 disposed around the outer periphery of the cylindrical portion 61a.
Opening / closing operation linked with.

On the other hand, the lens barrel has a cylindrical second moving frame 64 movable within the first moving frame 52 described above.
And a second motor 65 for moving and driving the second moving frame 64 and an interlocking mechanism thereof. The second moving frame 64 supports the rear lens group 66.

As shown in FIGS. 1 and 5, the interlocking mechanism includes an output gear 67 of a second motor 65, reduction gears 68 to 71, an interlocking gear 73 fixed to a lead screw 72, and a second moving frame 64. And a cylindrical screw (female) 74 fixed to the upright portion 64a. Although a pulse motor is used as the second motor 65, it can be replaced with a DC motor using a photointerrupter as in the first motor 54.

The interlocking gear 73 rotates in conjunction with the terminal reduction gear 71. The interlocking gear 73 is fixed to one end of a lead screw 72 which extends through the upright portion 64a of the shutter frame 61 and the second moving frame 64 and is drawn rearward (to the left in FIG. 5).

As shown in FIG. 5, the lead screw 72 is urged by a pressing plate 72a so as to press the interlocking gear 73 against the shutter frame 61, thereby preventing the lead screw 72 from rattling in the horizontal direction.

The lead screw 72 has a cylindrical screw 7
The cylindrical screw 74 is screwed by the rotation of the lead screw 72 to move the second moving frame 64 in the optical axis direction (left and right direction in FIG. 5). That is, the second moving frame 64 is, as shown in FIG.
It is configured to be guided by a guide shaft 75 provided on the first moving frame 52 and move in the optical axis direction without rotating.

The second moving frame 64 is provided with a protruding arm 64b protruding forward (to the right in FIG. 6 ) through the notch 61b of the shutter frame 61. The protruding arms 64b and 64d The guide shaft 75 is slidably passed through the formed shaft hole. Note that the guide shaft 75 is provided with a shaft stopper 52 protruding from the front and rear ends of the first moving frame 52 into the frame.
It is supported by d and 52e.

The above-described zoom lens operates as follows. First, when the main switch is OFF, FIG.
As shown in (1), the first moving frame 52 and the second moving frame 64 are both in the retracted position. In other words, the operation state is such that the rear group lens 66 is moved backward most and the front group lens 62 is moved closest to the rear group lens 66.

When taking a picture, first, when the main switch is turned on, the first motor 54 is driven to rotate, and the first moving frame 52 is extended to a predetermined position (WIDE position), as shown in FIG. The state shown in FIG. That is, the rotation of the first motor 54 causes the moving gear 58 to rotate the drive ring 51, and the drive ring 51 moves forward in accordance with the helicoid screw. Therefore, the first moving frame 52 is pushed by the drive ring 51 and is extended to a predetermined position.

The movement of the first moving frame 52 is divided and controlled by a gray code provided between the fixed frame 50 and the first moving frame 52, and the first motor 54 stops. Also, the first moving frame 52
Is moved out in this manner, the second motor 65 is stopped, so the second moving frame 64 moves in the same direction together with the first moving frame 52, and moves forward as shown in FIG. 7B. .

When the first moving frame 52 is extended to a predetermined position, the second motor 65 is driven to rotate. As a result, the cylindrical screw 74 is screwed by the lead screw 72 to rotate the lead screw 72 by the interlocking gear 73 receiving the rotational force, and the second moving frame 64 is moved backward.
The state shown in FIG.

Since the operation of FIG. 7C is at the WIDE photographing position, when photographing is performed in this state, focusing is performed by driving and rotating the first motor 54 by a release operation. That is, the distance measurement signal is pulse-converted by the control circuit, and the first motor 54
Is driven to rotate. At this time, the front lens group 62 and the rear lens group 66 are both moved forward to perform focusing.

When performing zooming, FIG.
In the operation state of the WIDE position shown in FIG.
4 is driven to rotate, and as shown in FIG. 8B, the first moving frame 52 is extended toward the TELE position.

When the extension position of the first moving frame 52 is determined, the first motor 54 stops, the stop position is detected in gray code, and based on this detection, the first moving frame 52 and the first moving frame 52 are stopped. A position code (branch point detection) signal of the two moving frame 64 is output, and the control circuit determines the rotation direction and the pulse control time of the second motor 65 based on the position code signal, and the second mode. And the motor 65 is driven to rotate. As a result, the second moving frame 64 moves to perform zooming, and at the TELE position, the operation state is as shown in FIG. 8C.

Focusing is performed at a zoomed position by rotating the first motor 54 in accordance with the release operation. At this time, the front group lens 62 and the rear group lens 66 are both moved forward to perform zooming.

If the distance measurement is performed at a position closer to the telephoto position than the closest position, the second motor 65 is driven to rotate in response to the release operation, and the rear lens group 66 is operated. Is displaced to a predetermined position to perform tele-macro focusing.

When the main switch is turned off, the second motor 65 is driven to rotate, and the rear group lens 66 is moved to the front group lens 6.
2 and this condition is detected in gray code. Then, in response to the detection signal, the first motor 54 is driven to rotate, and the front lens group 62 and the rear lens group 66 are retracted integrally.

That is, when the main switch is turned off, the first motor 54 rotates in the reverse direction, and the rotation of the first motor 54 causes the moving gear 58 to rotate the drive ring 51.
, And the drive ring 51 moves backward according to the helicoid screw. Therefore, the first moving frame 52 is pulled by the drive ring 51 and returns to the retracted position. When the first moving frame 52 returns to the most retracted position, it is detected by gray code, and the motor 54 is stopped by this detection.

In the above-described embodiment, the upright portions 53b and the protruding portions 53d of the friction spring 53 are formed at four places. However, the numbers of the upstanding portions 53b and the protruding portions 53d can be arbitrarily changed. . When the number of the standing portions 53b is changed, the locking projections 5 of the first moving frame 52 are correspondingly changed.
2a is provided.

The connection structure between the friction spring 53 and the first moving frame 52 is not limited to the above-described one. For example, a hole is provided in this portion instead of the locking projection 52a of the first moving frame 52. The tip of the upright portion 53b of the friction spring 53 may be bent, and the bent portion may be hooked and connected to the above-described hole.

This connecting structure may be configured as shown in FIG. That is, the first moving frame 52 is provided with a screw hole at this portion instead of the locking projection 52a, and a cylindrical stopper ring 76 having a flange 76a is provided instead of the friction spring 53. Then, the retaining ring 76 is screwed into a screw hole of the first moving frame 52 through a screw hole provided at a distal end portion of the retaining ring 76, and the retaining ring 76 and the first moving frame 52 are fastened. With such a connection, the drive ring 5 can be compared with the friction spring 53 shown in the above embodiment.
1 can be reduced.

In the above-described embodiment, the fixed frame 50
The helicoid screw 50a formed on the inner peripheral surface is provided over substantially the entire area of the fixed frame 50 in the axial direction. You can also. The helicoid screw 50a and the helicoid screw 51a of the drive ring 51
May be formed as a precision screw if the moving amount of the drive ring 51 is small.

The fitting of the fixed frame 50 and the first moving frame 52
The present invention is not limited to the configuration in which the outer periphery of the first moving frame 52 is fitted around the inner periphery of the fixed frame 50. A number of keys 52b of the first moving frame 52 and a number of key grooves 50c of the fixed frame 50 are provided. 52b
And the key groove 50c may be fitted.

The key 52 of the first moving frame 52 described above
b is formed integrally with the first moving frame 52, but a key 52b may be formed by fixing a protruding member.
The zero key groove 50c may be formed as a long hole.

When the gear 51b formed on the drive ring 51 is an internal tooth and a pinion is meshed with the internal tooth, the drive ring 51 is rotationally moved by a AF single-lens reflex camera via a coupler provided on a flange surface of a mount. It is also possible.

Further, if an intervening spring between the flange plate 53a or the flange 76 a and the fixing frame 50 of the retaining ring 76 of the friction spring 53, to the fixed frame 50 of the drive ring 51 can be attached without causing backlash As a result, rotation unevenness of the drive ring 51 does not occur.

For example, as shown in FIG.
The spring receiving portion 50d and the flange plate 53 of the friction spring 53 are formed integrally with the rear end side of the spring receiving portion 50d.
A coil spring 79 for pressure expansion is provided between the coil spring 79 and the coil spring 79. Also, as shown in FIG. 11, the end of the rising portion of the friction spring 53 is bent to form a spring receiving portion 53e, and a space between the spring receiving portion 53e and the spring receiving portion 50d of the fixed frame 50 is provided around the optical axis. A ring-shaped pressure expanding spring 80 wound in the direction is provided.

Further, in the above embodiment, the drive ring 51 is provided inside the fixed frame 50 at the rear, but the drive ring 51 may be provided inside the fixed frame 50 at the front. That is, the driving ring 51 pushes the first moving frame 52 by the backward movement of the driving ring 51, and pulls the first moving frame 52 by the forward movement of the driving ring 51 to move the first moving frame 52.

[0048]

As described above, in the lens moving device according to the present invention, the moving frame and the drive ring for moving the moving frame can be formed with substantially the same diameter, so that the lens barrel diameter is reduced. As a result, optical devices such as cameras can be downsized. And, in particular,
In the present invention, the drive ring and the moving frame are connected by the connecting member.
The drive ring is connected to the drive ring via a connecting member.
Mechanical force of screwing with fixed frame by applying pressing force by member
Mechanical play and rotation
A drive ring with no unevenness, and the moving frame can be moved with high accuracy
Done.

Further, as compared with a lens barrel using a cam frame, the lens barrel structure is simplified and the production cost can be reduced, so that the apparatus is suitable for reducing the cost. Furthermore, this apparatus is an apparatus having an extremely wide range of use, for example, it can be used not only for a zoom lens but also for a single focus lens.

[Brief description of the drawings]

FIG. 1 is a front view showing a lens barrel of a zoom lens provided with a lens moving device according to the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 1;

FIG. 4 is an enlarged perspective view of a friction spring provided in the moving device.

FIG. 5 is a sectional view taken along line CC in FIG. 1;

FIG. 6 is an end view cut along the line DD in FIG. 1;

FIG. 7 is an explanatory diagram showing an operation process of extending a zoom lens provided with the moving device to a photographing position.

FIG. 8 is an explanatory diagram showing a zooming operation process of the zoom lens.

FIG. 9 is a partially enlarged cross-sectional view showing an embodiment in which the drive ring and the first moving frame are connected using a cylindrical retaining ring.

FIG. 10 is a partially enlarged cross-sectional view showing an embodiment in which mechanical play of a drive ring is absorbed by a pressure expanding action of a coil spring.

FIG. 11 is an enlarged sectional view similar to FIG. 10, showing an embodiment in which the mechanical play of the drive ring is absorbed by the spring expanding action of the ring embodiment.

[Explanation of symbols]

 Reference Signs List 50 Fixed frame 50b Helicoid screw 51 Drive ring 51a Helicoid screw 51b Gear 52 First moving frame 53 Friction spring 53a Flange plate 53b Upright portion 54 First motor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-7919 (JP, A) JP-A-64-11212 (JP, A) JP-A-63-304216 (JP, A) JP-A-5-112 127064 (JP, A) JP-A-6-34865 (JP, A) Japanese Utility Model Application Sho 60-13511 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 7/04-7 /Ten

Claims (1)

(57) [Claims] 1. A fixed frame having a cylindrical shape with an inner peripheral surface formed by screwing, and a movable frame for holding a lens is mounted inside the fixed frame so as to be able to advance and retreat without rotating around the cylindrical axis of the fixed frame. And at the same time, have the same frame diameter as the moving frame.
The screw and the interlocking mechanism for screwing the screws of the fixed frame around
Thus it provided a gear for rotating includes a drive ring which moves driven rotary drive to the cylindrical axis direction of the fixed frame, whereas, the one side engaged with the drive ring, the other side in the above moving frame Stop and give the moving force of the drive ring to the moving frame
A connecting member that provides a spring force to the coupling member, the coupling
Push the drive ring through the member in the cylinder axis direction of the fixed frame.
Pressing, mechanical play of screwing of drive ring and fixed frame
A moving member for holding the lens by moving a driving ring by rotating the driving ring.