JP2814245B2 - Variable focus lens driving device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a variable focus lens driving device, and
Specifically, at least the first lens group and the
A second lens group is provided for focusing the first lens group.
Variable focus lens consisting of variable focus optical system as lens
Set the focal length between the longest focal length and the shortest focal length.
The varifocal lens is used to change the magnification
The present invention relates to a variable-focus lens driving device that is driven.
You. (B) Conventional technology In recent years, computerization and electrification of cameras have progressed,
Move the focal length of the shooting optical system with one touch operation.
Iwayu can be set (changed) in stages or in multiples
Many variable focus cameras have been proposed.
The rotation of the cam ring provided with the cam groove causes the cam groove to rotate.
The lens frame on which the cam pins are slidably fitted
Driving (moving) in the optical axis direction to change the focal length
Is generally used. However, such a conventional device has a relatively simple configuration.
Although it has the advantage of having
Is difficult and requires high processing accuracy.
Costly and reduce the length of the cam ring in the optical axis direction.
And the lens barrel cannot be made compact.
won. Further, as disclosed in JP-A-60-79314.
In addition, instead of the above cam ring, a single drive screw
Some drive the lens frame in the optical axis direction.
Since the driving force is concentrated in a part, the movement of the lens frame
In addition to the problem that it is difficult to perform smoothly, the lens
The frame is tilted and the perpendicularity of the lens, which should be perpendicular to the optical axis, is maintained
The problem is that it is not possible to achieve the expected optical performance
was there. And to solve this problem, multiple drive screws
It is conceivable to use
The transmission mechanism for transmitting the driving force becomes complicated,
A new problem such as a remarkable increase in the diameter of the frame or the like occurs. One
In other words, reducing the diameter of the lens barrel without blocking the effective light flux
It is extremely difficult to incorporate the above transmission mechanism under the above restrictions.
It is difficult. (C) Objective The present invention has been made in view of the above-mentioned circumstances.
It is important to ensure that the optical properties are not adversely affected.
The diameter of the lens barrel frame etc. can be reduced, and it can be compared with high accuracy.
Despite being able to vary the focal length over a wide range,
The whole device can be made smaller than before, and it is inexpensive
To provide a variable-focus lens driving device that can be manufactured
It is in. (D) Configuration In order to achieve the above object, the present invention
At least a first lens group and a second lens group
And a variable focus lens, wherein the first lens group is a focusing lens.
Longest focal length of varifocal lens consisting of point optics
Variable magnification operation arbitrarily changes from the distance to the shortest focal length
Variable focus lens that drives the variable focus lens
Fixed parts of optical devices such as cameras
And a fixed frame fixed to the optical axis inside the fixed frame.
A lens barrel frame movably supported along the first lens;
With the lens group supported for focusing operation,
First group frame supported so as to be able to move parallel to the optical axis
And the first lens group fixedly supporting the second lens group.
The first frame is supported inside the group frame so as to be movable in parallel with the optical axis.
A second group frame linked in a predetermined relationship with the movement of the group frame;
A drive unit including a motor or the like serving as a drive source of the above-described zooming operation
To move the lens barrel along the optical axis,
At least one end is connected to the fixed frame and the other end is
At least three lens barrel drive screws engaged with the first group;
In order to move the frame along the optical axis, one end of the first group
The other end is connected to the frame and the other end is screwed to the first group drive gear.
And three first group drive screws and the lens barrel frame or the
The above-mentioned drive unit is disposed coaxially with the optical axis on one side of the group 1 frame.
The driving force from a moving part is transmitted to the lens barrel driving gear and the first group.
A circular hole is drilled and transmitted to the drive gear, and teeth are
A transmission mechanism comprising an annular gear formed with a wheel.
And the lens barrel drive gear and the first group drive gear
The lens barrel frame and the rotation mechanism are driven to rotate by the transmission mechanism.
The first lens frame to a position corresponding to the longest focal length
From the position corresponding to the shortest focal length
The effective light flux on the inner peripheral surface of the ring gear of the transmission mechanism.
It is characterized in that it is configured not to block. Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings.
explain. FIG. 1 is a view showing a variable focus lens driving device according to the present invention.
FIG. 2 is a partially cutaway perspective view showing the entire configuration of one embodiment.
You. In FIG. 1, 1 is fixed to a stationary part such as a camera.
The fixed frame 3 is an optical axis passing through the approximate center of the fixed frame 1, 1a and
And 1b are the object side of this fixed frame 1 and the film, respectively.
At a surface side (neither is shown) end, substantially perpendicular to the optical axis 3
Front and rear plates, 1c and 1d
The front plate 1a and the rear plate 1b are punched out in a rectangular shape.
The front window and the front window for inserting (advancing and retracting) the lens barrel described later
And a rear window through which the photographing optical axis passes. 2 is disposed at the position of the rear window 1d on the optical axis 3,
The upper, lower, left and right peripheral parts are planes parallel to the optical axis 3.
This is the third lens that has been scraped off. 4 is disposed inside the fixed frame 1 and extends along the optical axis 3.
The above-mentioned lens barrel frame, which is movably supported, 4a to 4c Yes
The displacement also constitutes the lens barrel 4, of which 4a is the center
Is a box-shaped lens barrel arranged with the optical axis aligned,
4b is a cross section orthogonal to the optical axis 3 of the lens barrel 4a (that is,
Surface), which is slightly larger than the surface of the lens barrel 4a.
A lens barrel first substrate provided at an end thereof substantially at right angles to the optical axis 3;
4c keeps a slight distance behind this lens barrel first substrate 4b.
And a second lens barrel formed substantially in the same manner as the first lens barrel substrate 4b.
In the following, these lens barrel first substrate 4b and lens barrel second substrate
4c may be collectively referred to as a lens barrel substrate 4d. 5 is closest to the subject (not shown) on the optical axis 3
A first lens group as a first lens group disposed on the side;
5a supports the first lens group 5 so that focusing operation can be performed.
1 is a cylindrical first lens frame. 6 is the above inside
With the first lens frame 5a supported, the upper
A first group frame supported so as to be able to move parallel to the optical axis 3;
6a, 6b and 6c form this first group frame 6, of which 6a
Is a rectangular cylindrical portion along the optical axis 3, and 6b is a rear end of the cylindrical portion 6a.
And is slightly larger than the cross section of the cylindrical portion 6a.
The first group substrate 6c made of a plate-like member having an area
Gear support connected perpendicularly from the edge of the plate 6b toward the rear
Department. The first lens group 5 (first lens frame 5a) is a first group frame.
6 moves integrally, while the first group frame 6 moves.
The focusing mechanism (not shown) disposed on the inner wall of the
It moves independently of the first group frame 6 to serve as a focusing lens.
It is configured as follows. 7 is disposed behind the first lens group 5 on the optical axis 3.
The second lens group 7a as the second lens group provided is
Cylindrical cylinder for fixing and supporting the second lens group 7 coaxially with the optical axis 3
The second group frame 7b is formed on the optical axis 3 on the outer periphery of the second group frame 7a.
A cam pin that is planted at a right angle and abuts a cam surface described below,
7c is similarly attached on the outer periphery of the second group frame 7a,
Fork that prevents the rotation of the shaft and guides the movement in the three directions of the optical axis
Slider 7d having the shape of a part is also provided on the outer circumference of the second group frame 7a.
The implanted spring hook 8 is connected to the first group frame 6 (specifically,
The fork-shaped part of the slider 7c fixed to the first group substrate 1b)
Rod-shaped second group frame guide that slidably fits with both ends 9
The second group frame 7a is fitted into the inner periphery of the cylindrical member having an opening.
In this state, the outer periphery is provided at the center of the first group substrate 6b.
Into the hollow bearing part, and moved in the optical axis 3 direction.
The second is rotatably supported around the optical axis 3 without moving.
The second group frame cam 9a is provided at the front edge of the second group frame cam 9.
The cam surface which slides on the cam pin 7b, 9b is the second group frame
9 is a crown gear fixed to the rear end. 10a and
10b and 10b are given a tensile force to
The second group spring hung between the hook 7d and the first group substrate 6b
is there. 11 is a motor as a drive unit, 12 is a driving gear of the motor 11
Deceleration consisting of reduction gears 12a, 12b, driven by 11a
The gear train 13 has an oval hole at the center, and
Drive gear 13a driven by motor 11 via 12
Are inserted through the bearing holes formed in the lens barrel substrate 4d.
The ends are the front plate 1a and the rear plate 1b of the fixed frame 1, respectively.
At the rear end of the rear plate 1b.
The oval section in which the oval hole of the dynamic gear 13 is fitted and fixed.
It is a drive shaft composed of a rod-shaped member parallel to the optical axis 3 having a shape.
13b is sandwiched between the lens barrel first substrate 4a and the lens barrel second substrate 4b.
And has an oval shaped insertion hole, into which the drive shaft
13a is inserted and the rotational force of the drive shaft 13a is transmitted.
In the direction of the optical axis 3 under the screw action of the drive screw
Movement adapted to move integrally with the lens barrel substrate 4d
Gear. 14a, 14b, 14c, 15, 16a, 16b, 16c, 17a, 17b, 17c
Also rotatable between the lens barrel first substrate 4b and the lens barrel second substrate 4c.
14a, 14b and 14c are both
A small-diameter gear is integrated with the front surface of both end surfaces.
16a, 16b, 16c, 17a, 17b, 17
c has a female screw threaded into a hole drilled in the center
You. 14a is a transmission gear meshing with the moving gear 13b, 15
Meshes with this transmission gear 14a, and the photographing light flux (effective
Light beam) so that it can pass without vignetting
Ring gear composed of gears having a circular through hole formed therein,
14b and 14c are transmission gears meshing with this ring gear 15, 16
a, 16b, and 16c are included in the transmission gears 14a, 14b, and 14c, respectively.
First group drive gears 17a, 17b, 17 meshing with small diameter gears
c is a lens barrel drive meshing with the transmission gears 14a, 14b, 14c, respectively.
It is a dynamic gear. Hereinafter, the transmission gears 14a, 14b, 14c
The transmission gear 14 and the first group drive gears 16a, 16b, 16c collectively
The first group drive gear 16 and the lens barrel drive gear 17
a, 17b, and 17c may be collectively referred to as the barrel drive gear 17.
You. The transmission gear 14, the ring gear 15, and the lens barrel drive gear
(A) The transmission mechanism is composed of 17 and the first group drive gear 16.
doing. 18 is such that ends 18a and 18b are non-rotating and slightly
The back plate 1b and the front plate 1a are supported by
For example, a right-hand screw is screwed over almost the entire length to
A lens barrel parallel to the optical axis 3 screwed with the female screw of the dynamic gear 17a
The drive screw 19 has the same end frame 19a, 19b
1 and is screwed into the female screw of the lens barrel drive gear 17b.
Similarly, the barrel drive screw 20 is the female of the barrel drive gear 17c.
Lens drive screws 21, 22 and 23 screwed into the screws
The front end is non-rotatable at the peripheral edge of the first group substrate 6b.
And has a slight play while moving away from the first group substrate 6b.
It is supported without falling off, for example, the left
Female thread of the first group drive gears 16a, 16b and 16c
The first group of drive screws that are approximately parallel to the optical axis
is there. The lens barrel drive screws 18 to 20 and the first group drive
Three driving screws are composed of screws 21 to 23 respectively.
I have. 24, 25 and 26 are drilled at the periphery of the lens barrel substrate 4d
In a state of being inserted through the guided hole, substantially parallel to the optical axis 3,
The front and rear ends are the front plate 1a and the rear plate 1b, respectively.
(Ie, a guide shaft fixed to the fixed frame 1). 27
And 28 are the lens barrel substrate 4d of these guide shafts 25 and 26 and
Coil coils inserted with compression force applied between
It is a lens barrel spring composed of a spring (guide shaft 24
Is similarly provided). 29 to 31 are pulled between the first group substrate 6b and the lens barrel first substrate 4b.
This is a first group spring that is applied and suspended. 32 is parallel to the optical axis 3 and less than the side wall (not shown) of the lens barrel 3a.
The mirror located inside and connected to the front side of the lens barrel first substrate 4b
It is a torso rack. 33 is a cam drive arranged on the gear support 6c
The gear train 33a forms the first stage of this cam drive gear train 33
The pinion 33b meshing with the lens barrel rack is the gear train 33.
A connecting gear that constitutes the final stage and meshes with the crown gear 9b.
is there. Although not shown, a plurality of fixed to the lens barrel 4
The guide axis parallel to the optical axis 3 is, for example, the first group substrate 6b.
The light of the first group frame 6 is inserted through a guide hole formed in the peripheral portion.
It is configured to guide axial movement (position regulation)
I have. The first lens group 5, the second lens group 7, and the third lens group
The variable focus optical system is constituted by the lens 2. In the state shown in FIG. 1, the focal length is near the longest focal length.
This shows the tele state set nearby. Also, once the lens barrel drive gear 17 and the first group drive gear 16
Rolling of the lens barrel drive screws 18-20 and the first group drive screws 21-23
It corresponds to one pitch. In addition, in the drawings following FIG.
The same reference numerals are given to the same members as the members,
Omitted. FIG. 2 shows the transmission path of the driving force (rotational force).
Schematic of the transmission mechanism viewed from the rear side of the optical axis 3 (the film surface side)
FIG. FIG. 3 is representative of, for example, the first group drive gear 16b of FIG.
FIG. 3 is a longitudinal sectional view showing a part of a transmission mechanism as an enlarged view.
You. In FIG. 3, reference numeral 34 denotes a male thread portion of the first group drive screw 22;
35 is a female thread portion of the first group drive gear 16b, and 36 is a first group drive gear.
A receiving from the lens barrel substrate 4d due to the thrust force generated in
Step portion for reducing the frictional force applied to the first group drive gear 16b
Of the first group drive gear 16b from the center of both end faces
It is a cylindrical shaft portion formed in a cylindrical shape. FIG. 4 shows, for example, the lens barrel drive screw 19 of FIG.
It is a perspective view which expands and shows the structure of the both ends. In FIG. 4, reference numeral 39 denotes a male screw of the lens barrel drive screw 19 which is screwed.
Threads 39a and 39b are rear and front respectively
The end faces, 40a and 40b, of the threaded portion 39 are the end faces, respectively.
39a and 39b are integrally connected to each other.
Oval and round axes made small, 41a and 41b
The shapes of the oval shaft 40a and the round shaft 40b are similar to each other, and
The rear plate 1b and front plate 1a are slightly larger than their outer diameter.
It is a support hole drilled. In order to make the configuration easy to understand, the above-mentioned oval shaft 40a and
And the length of the round shaft 40b is exaggerated. Also, actually
In the assembled state, the front plate 1a is in sliding contact with the end face 39b, and the rear plate 1b
Is disposed at a position where it comes into sliding contact with the end face 39a, and the barrel drive screw 19
Is precisely positioned at its ends 19a and 19b in the axial direction.
And has a small degree of freedom in the circumferential direction.
Have been. FIG. 5 shows, for example, the first group drive screw 22 of FIG.
To enlarge the configuration of the end supported on the first group substrate 6b.
FIG. In FIG. 5, reference numeral 42 denotes a thread portion of the first group drive screw 22;
Is an end face of the screw portion 42, and 44 is an axially continuous
A shaft part with a smaller outer diameter than the thread part
The support holes 46 formed in the first group substrate 6b through which the parts are inserted
The shaft portion 44 is formed at a portion protruding from the first group substrate 6b.
This is an E-ring fitted in the surrounding groove. E-ring 46
Is disposed in sliding contact with or very close to the first group substrate 6b.
The inner diameter of the support hole 45 is slightly larger than the outer diameter of the shaft 44.
It has a small degree of freedom in the diametric direction,
Therefore, the position is regulated, and
To prevent the shaft portion 44 from separating from the first group substrate 6b
Is configured. FIG. 6 to FIG. 8 show the variable power of the present embodiment shown in FIG.
A vertical diagram schematically showing the three states involved in operation and storage
Fig. 6 is a cutaway side view, and Fig. 6 shows the storage state when not in use.
FIG. 7 shows a case where the focal length is switched to the shortest focal length side.
FIG. 8 shows the telephoto state described above.
ing. 6 and 7, reference numeral 47 denotes the front of the first lens group 5.
, The object 48 is located behind the third lens 2
Film side. 5a is a first lens frame, which is shown in FIG.
As described in the description of the above, it is directly fixed to the first group frame 6
The focusing mechanism fixed to the first group frame 6
So that the relative position with respect to the first group frame 6 can be changed by the
Supported. Therefore, while the focusing mechanism is not operating,
It moves integrally with the first group frame 6 and the focusing mechanism operates.
Can move along the optical axis 3 independently of the first group frame 6
It is configured as follows. 9 to 11 show the structure of the first group frame 6 and the second group frame 7a.
FIG. 9 is a side view schematically showing a partly broken structure, and FIG.
State, Fig. 10 shows the wide state, and Fig. 11 shows the stored state.
Each is shown. In these figures, the correspondence between the cam surface 9a and the second group frame 7a is shown.
The second group frame cam 9 is used as a reference to make it easier to understand the relationship.
However, in practice, it was also described in the description of FIG.
As described above, it is the second group frame cam 9 that rotates.
It is the second group frame 7a that moves linearly with respect to the axis 3. 9 to 11, reference numeral 49 denotes the optical axis 3 from the second group frame 7a.
Is a protrusion that extends rearward along
Stopper part 1e which is a part of fixed frame 1 in wide state
Is configured to be in a position immediately before contact. 12 and 13 show the positions of the effective light flux and the ring gear.
Fig. 12 is a vertical side view schematically showing the relationship.
FIG. 13 corresponds to the telephoto state. 12 and 13, reference numeral 50 denotes an effective luminous flux, and 51 denotes a circle.
An inner peripheral surface 52 of the ring gear 15 is an entrance surface of the third lens 2.
That is, as shown in FIG. 12, the ring gear 15 has a wide shape.
In the state, the diameter of the inner peripheral surface 51 does not touch the effective light beam 50
It is set to the minimum value (not interrupted). Therefore, to explain the operation, the third lens in the wide state is described.
The effective light beam 50 incident on the lens 2 has the largest cross-sectional area of the light beam.
So that the inner peripheral surface of the ring gear 15
Since the diameter of 51 is set, the entrance surface 52 of the third lens 2
The direction in which the ring gear 15 moves away from the
The direction from the wide state to the telescopic state is
Thus, the annular light 15 does not block the effective light beam 50. That is,
A circle is attached to the fixed frame 1 (more specifically, the rear plate 1b) as an immovable member.
Compared to the case where the ring gear 15 is attached,
The advantage is that the diameter can be small, and finally the entire device
(The lens barrel frame 4 and the fixed frame 6) can be downsized.
You. The operation of the present embodiment configured as described above will be described. First, the transmission operation of the rotational force will be described with reference to FIGS.
Will be described. For example, the driving gear 11a of the motor 11 is clockwise.
And the drive gear
13 rotates counterclockwise, and this rotational force is transmitted via the drive shaft 13a.
To rotate the moving gear 13b counterclockwise. This move
The transmission gear 14a meshing with the gear 13b rotates clockwise,
The ring gear 15 meshing with this rotates counterclockwise,
The meshing transmission gears 14b and 14c rotate clockwise.
That is, all three transmission gears 14 rotate clockwise.
Because And mesh with these transmission gears 14, respectively.
Three barrel drive gears 17 and three first group drive gears
All 16 rotate counterclockwise. In other words, the source of motor 11
The moving gear 11a, the lens barrel driving gear 17, and the first group driving gear 16,
Rotates in the opposite direction. Now, the tele state shown in FIG. 1, FIG. 8 and FIG.
Short focal length to the wide state shown in Fig. 7 and Fig. 10
The replacement operation will be described. As described above, the lens barrel drive gear 17 and
When the first group drive gear 16 rotates counterclockwise, the mirror
Lens barrel drive screw screwed into each female thread of barrel drive gear 17
If 18-20 is a right-hand thread, the lens barrel drive screws 18-20 are in the axial direction.
The lens barrel drive gear 17 itself rotates because it cannot move or rotate.
It moves toward the rear of the optical axis 3 while rotating.
With this movement, the lens barrel substrate 4d, that is, the lens barrel frame 4 is moved
Guide shafts 24-26 against the urging force of springs 27 and 28
Begins to retreat while being guided by. On the other hand, the first group drive gear 16 is screwed into each female screw.
When the first group drive screws 21 to 23 are left-handed screws, the first group drive
The gear 16 itself tries to move forward, but the optical axis direction is
As a result, the first group drive is performed.
Are moved to the rear of the optical axis 3, that is, the first group frame 6
A guide (not shown) is generated by the urging force of the first group springs 29 to 31.
Begin retreating while being guided by the shaft. That is, the first group frame 6
Is located in the lens barrel frame 4 retreating with respect to the fixed frame 1,
Further, the relative movement of the lens barrel 4 with respect to the lens barrel frame 4 is performed.
You. By this relative movement, that is, the first group substrate 6b
By moving in the direction approaching the lens barrel substrate 4d, the lens barrel is moved.
The gear support 6c is retracted with respect to the rack 32, and the lens barrel rack
The pinion 33a meshing with 32 rotates counterclockwise. This
Is transmitted through the cam drive gear train 33 to connect the gear 33b.
Is rotated clockwise, and the
The gear 9b rotates counterclockwise to rotate the second group frame cam 9 counterclockwise.
Rotate in the measuring direction. This rotation makes sliding contact with the cam surface 9a
The cam pin 7b is pulled backward by the second group springs 10a and 10b.
Moves diagonally backward along the slope of the cam surface 9a
However, the second group frame 7a is moved between the slider 7c and the second group frame.
Only linear motion in three directions of the optical axis is allowed by the id 8
Therefore, as a result, it is necessary to move backward parallel to the optical axis 3.
Become. These operations are further advanced, and the cam
The pin 7b reaches the wide position (substantially V-shaped part) of the cam surface 9a
When the second group frame 7a projects rearward from the first group substrate 6b
The protrusion amount is the largest, and the protrusion 49
It reaches just before par 1e. That is, as shown in FIG.
4 (more specifically, the barrel 4a) is the front window of the fixed frame 1.
Pull out slightly from 1a, and the first group frame 6 (more specifically, the cylindrical portion 6a)
Is slightly extended from the front end of the lens barrel 4a, and the second group frame 7a is
A wide state is reached in which the rearward protrusion amount is applied. Next, from the wide state shown in FIGS. 7 and 10, FIG.
And the storage operation leading to the storage state shown in FIG. 11 will be described.
The lens barrel drive gear 17 and the first group drive gear 16 are the same as described above.
Rotates counterclockwise. Therefore, the lens barrel frame 4 and the first
The group frames 6 continue to retreat as described above. Place
However, as shown in FIG.
The second group frame 7a retreats further because it comes into contact with the par 1e
And the position is maintained, but the first group frame 6 (the
The first group substrate 6b) and the barrel frame 4 are further retracted, so that
The cam pin 7b resists the spring force of the second group springs 10a and 10b
It will separate from the cam surface 9a forward. And the sixth
As shown in the figure, each of the lens barrel frame 4 and the first group frame 6
The front end is substantially aligned with the front plate 1a, and is located on the second group frame 7a.
The rearward projection amount is minimum (substantially zero), that is, the second
Storage in which the rear end of the group frame 7a is substantially aligned with the first group substrate 6b
To the state. Next, FIG. 1, FIG. 8, and FIG.
Simplified long focus switching operation to the telephoto state shown in the figure
explain. Drive the motor 11
By rotating 11a counterclockwise, the lens barrel drive gear
All of 17 and the first group drive gear 16 rotate clockwise
I do. Therefore, the lens barrel frame 4 is extended forward, and the extended mirror
The first group frame 6 further extends forward with respect to the body frame 4. Ma
Focusing only on the first group frame 6 and the second group frame 7a,
As shown in FIGS. 11 and 10, the first group frame 6 (first group substrate
Even if 6b) is extended, the second group frame 7a remains in the first group by the second group spring 10a.
Since it is pulled toward the substrate 6b,
Only the group frame 6 moves forward and reaches the position shown in FIG.
Has been restricted for the first time since the
Will be That is, the second group frame 7a moves
The cam surface 9a is not restricted during the id state. Further, the lens barrel frame 4 and the first group frame 6 advance, and the
Gear 9b rotates clockwise, and this rotation causes the cam surface to rotate.
The cam pin 7b sliding on 9a is pressed diagonally forward,
7c and the second group frame guide 8 convert the
The second group 7a is extended forward. 8 and 1
As shown in the figure, the lens barrel frame 4 is fixed to the fixed frame 1 by the first group frame.
6 is extended to the lens barrel frame 4 by substantially the maximum amount, respectively.
The frame 7a is also lowered by approximately the maximum amount in front of the first group substrate 6b, and the second group frame 7a
To a telephoto state in which the rear end of the lens is substantially aligned with the first group frame 6b.
You. Thus, according to the present embodiment, the fixed frame 1
Slidable along three guide axes 24-26 substantially parallel to the optical axis 3
The first lens group 5 is supported in the lens barrel 4 that is supported
Lens barrel frame with the first group frame 6 in a state substantially parallel to the optical axis 3
Moveable with multiple guide shafts (not shown) fixed to
Supported in the second group frame cam 9 and the second lens group
The second group frame 7a in a state that supports 7 is supported so as to be able to advance and retreat,
Transmitter driven via drive shaft 13a and moving gear 13b
The lens barrel frame 4 is divided into three lens barrel drive screws 18 to 20 depending on the structure.
And the first group frame 6 is moved by three first group drive screws.
The first group frame 6 and the lens barrel frame 4 are moved forward and backward at 21 to 23.
The second group frame 7a is moved forward and backward using the movement amount as a drive source.
Since the lens barrel 4 and the first group frame 6 move,
The posture of the first lens group 5 and the second lens group 7 becomes unstable
The disadvantage of the conventional example that
You. Further, the lens barrel frame 4 and the first group frame 6 are
Variable focal length with a variable focal length range
Despite being a point optical system, in the stored state,
The length in the direction of the optical axis 3 is almost the same as the fixed frame 1 and is extremely small.
Has the advantage that it can be compact and compact.
You. Further, an annular gear 15 is provided on the lens barrel frame 4 side as a moving member.
As described above with reference to FIGS. 12 and 13,
It does not block the effective light beam 50 compared to the case where it is provided in the fixed frame 1.
The diameter of the inner peripheral surface 51 of the ring gear 15 can be reduced,
This has the advantage that the entire device can be miniaturized. Also, three transmission gears 14 are arranged on the outer circumference of the ring gear 15
(Meshing), three first groups with a simple configuration
When the drive gear 16 and the three barrel drive gears 17 can be driven
There are advantages. In addition, the conventional cam ring that requires a large production cost is used
Not so, the production cost can be greatly reduced
The advantage is that Also, the amount of movement of the first group frame 6 and the lens barrel frame 4 is the same as the two-stage gear.
Can be easily set by the gear ratio of the transmission gear 14
Therefore, there is an advantage that the degree of freedom in design is large. The lens barrel drive screws 18-20 and the first group drive screws 21-
23 can also be mirrored by changing
The amount of movement of the body frame 4 and the first group frame 6 is set relatively freely.
Can be The lens barrel drive screws 18 to 20 are respectively provided at both ends 18a,
Precise position regulation in the axial direction for 19a, 18b and 19b
But it is moderate in the diameter direction (margin)
Lens barrel drive screws 18-20, first group drive
Screws 21 to 23 and the barrel drive gear 17 and
And the first group drive gear 16 and the entire transmission mechanism
Even if there is an error, it can give unreasonable force to these
And smooth operation and overload of motor 11 etc.
There is an advantage that there is no need to worry. Also, once the lens barrel drive gear 17 and the first group drive gear 16
Rolling of the lens barrel drive screws 18-20 and the first group drive screws 21-23
Since the movement is one pitch, it is said that the feeding accuracy is high.
There are advantages. In addition, members requiring a large installation space such as the motor 11
Is fixed to the fixed frame 1 to be an immovable member.
There is an advantage that a large space is not required. Further, the lens barrel frame 4, the first group frame 6, and the second group frame 7a are arranged in time series.
(Sequential) instead of moving at the same time,
There is an advantage that the operation time can be reduced. Also, the second group springs 10a and 10b, the lens barrel springs 27 and 28, and
The lens barrel drive screws 18 to 20 and the first group springs 29 to 31
And bucklers related to the first group drive screws 21-23
Brushes and mechanical backlash etc.
Because it was made to hold, the shadow of the backlash etc.
It has the advantage of not being affected. Note that the present invention is not limited to the above-described embodiment.
Various modifications may be made without departing from the spirit of the invention.
It can be. For example, the lens barrel drive screws 18-20 must be right-handed,
The first group drive screws 21 to 23 are not limited to left-handed screws.
You may change it according to the specification of a structural part. Regarding the spring, in the above embodiment,
Are compression springs as barrel springs 27 and 28,
Tension as the second group springs 10a and 10b and the first group springs 29 to 31
Spring is used, but if you choose how to hang, the opposite bias
A spring with force may be used. The cross section of the drive shaft 13a is not limited to the oval shape.
And compatibility with the driving gear 13 and the moving gear 13b.
If desired, other shapes such as splines may be used. The crown gear 9b and the connecting gear 33b are
You may comprise by a gear. Further, the transmission mechanism is not limited to being provided on the lens barrel frame 4 side.
It may be provided on the first group frame 6 side. (E) Effect As described in detail above, according to the present invention, the following
Device for variable focus lens having various advantages such as
Can be provided. First, the lens barrel frame and the first group frame are each driven to zoom.
At least three lens barrel drive gears and a first group drive gear
To transmit the driving force from the drive unit
An annular gear is used as the mechanism, and the gear is the same as the optical axis.
As an axis, it is arranged on either the lens barrel frame or the first group frame.
Did you move along the optical axis in a double collapsible form?
Very variable focus range (zoom ratio)
Realizes the focusing optics while the entire device is in the stowed state
Extremely small because the length in the optical axis direction is almost the same as the fixed frame
And realize compactness at the same time,
For each of the three barrel drive screws and the first drive screw
The screwed lens barrel drive gear and the first group drive gear
The transmission drive mechanism can be greatly simplified.
You. Secondly, the annular gear is mounted on either the lens barrel frame or the first group frame.
It is arranged on one of the movable members and coaxially with the optical axis,
Position the body frame and the first group frame at the position corresponding to the longest focal length
To the position corresponding to the shortest focal length.
The effective light flux on the inner peripheral surface of the ring gear
So that the ring gear is fixed to the fixed frame.
In comparison with the case where the effective luminous flux is not
The diameter of the car can be made smaller and the overall device can be made smaller.
Can be manifested. Third, at least three lens barrel drives connected to the fixed frame
A lens barrel frame movably supported in the optical axis direction along a dynamic screw
Inside, the first group frame supporting the first lens group is light
Supported movably in a state substantially parallel to the axis, and
At least three first group drives connected with the group frame to the first group frame
It is supported movably along the optical axis by a dynamic screw, and the motor
Drive force from a drive unit such as
Each of the lens barrel drive gears and the plurality of first group drive gears.
Drive the lens barrel frame and the first group frame along the optical axis
And the relative movement amount between the first group frame and the lens barrel frame is determined by a driving source.
The lens barrel is configured to move the second group frame forward and backward.
The first lens group and the second lens are moved with the movement of the frame and the first group frame.
The conventional disadvantage that the posture of the lens group becomes unstable has been removed.
Therefore, the lens group does not collapse when the focal length changes.
Variable focal length lens that can extend the lens group with high accuracy
And a driving device of a group of components. Fourth, the movement amount of the first group frame and the lens barrel frame is
Easy setting by reduction ratio and lead of each drive screw
Therefore, the degree of freedom in design is large.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view, partially cut away, showing the entire configuration of an embodiment of a variable focus lens driving device according to the present invention, and FIG. 2 is a diagram shown in FIG. FIG. 4 is a schematic view of the transmission mechanism as viewed from the rear to show a transmission path of a driving force (rotational force) according to the embodiment;
FIG. 3 is an enlarged longitudinal side view showing a part of the transmission mechanism in the embodiment shown in FIG. 1, and FIG. 4 is an enlarged view of the configuration of both ends of the lens barrel drive screw shown in FIG. FIG. 5 is an enlarged longitudinal sectional view showing in detail the configuration of the end of the first group drive screw shown in FIG. 1 on the side supported by the first group substrate, and FIGS. FIG. 3 schematically shows three states involved in the operation of the embodiment shown in FIG. 1. FIG. 6 shows the stored state when not in use, and FIG. 7 and FIG. 9 to 11 respectively show a wide state and a telephoto state in which the focal length is switched to the short focal length side and the long focal length side, and FIGS. 9 to 11 schematically show the operation of the first group frame and the second group frame, respectively. The side view shown in FIG. 12, FIG. 13 and FIG.
FIG. 3 is a vertical sectional side view schematically showing a positional relationship between an effective light beam and a ring gear in each of a wide state and a tele state. 1 ... fixed frame, 1a ... front plate, 1b ... rear plate, 1c ... front window, 1d ... rear window, 2 ... third lens, 3 ... optical axis, 4 ... lens barrel frame, 4a lens barrel, 4d lens barrel substrate, 5 first lens group, 6 first group frame, 6b first group substrate, 7 second lens group, 7a second Group frame, 7b: cam pin, 8: Second group frame guide, 9: Second group frame cam, 9a: Cam surface, 9b: Crown gear, 10a, 10b: Second group spring, 11 ... ... Motor, 12 ... Reduction gear train, 13 ... Drive gear, 13a ... Drive shaft, 13b ... Movement gear, 14 (14a, 14b, 14c) ... Transmission gear, 15 ... Ring gear, 16 ( 16a, 16b, 16c) first group drive gear, 17 (17a, 17b, 17c) lens barrel drive gear, 18-20 lens barrel drive screw, 21-23 first group drive screw 24 to 26… Guide shaft, 27, 28… Barrel spring, 29 to 31… First group spring, 32… Barrel rack, 33… Cam driving gear train, 33a ...... pinion, 33b ...... connection gear, 50 ...... effective light beam, the inner peripheral surface of 51 ...... annular gear.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02B 7/04 G02B 7/08 G02B 7/10

Claims (1)

(57) [Claims] At least the first lens group and the second lens group on the same optical axis.
And a variable magnification lens for arbitrarily changing the focal length of a variable focal length lens composed of a variable focal length optical system using the first lens group as a focusing lens between a longest focal length and a shortest focal length. In the variable focus lens driving device for driving the variable focus lens to operate, a fixed frame fixed to an immovable portion of an optical device such as a camera, and movable along the optical axis inside the fixed frame. A lens barrel supported by the
A first group frame supported inside the lens barrel frame so as to be able to move in parallel with the optical axis while the first lens group is supported so as to be able to perform a focusing operation; and the second lens group. A second group frame which is supported inside the first group frame so as to be movable in parallel with the optical axis in a fixedly supported state and interlocks in a predetermined relationship with the movement of the first group frame; And a driving unit including a motor or the like serving as a driving source for moving the lens barrel along the optical axis, at least one end connected to a fixed frame and the other end screwed to a lens barrel driving gear. Lens barrel drive screw, and at least three third screws having one end connected to the first group frame and the other end screwed to the first group drive gear for moving the first group frame along the optical axis. A first group driving screw, and the driving section, which is disposed coaxially with the optical axis on one of the lens barrel frame and the first group frame. A transmission mechanism for transmitting the driving force to the lens barrel driving gear and the first group driving gear, the transmission mechanism comprising an annular gear having a circular hole formed therein and a gear formed on an outer peripheral portion; The lens barrel drive gear and the first
When the group drive gear and the transmission mechanism are rotated and driven to double-sink the lens barrel frame and the first lens frame from a position corresponding to the longest focal length to a position corresponding to the shortest focal length, A driving device for a varifocal lens, wherein an effective light flux is not blocked by an inner peripheral surface of an annular gear of the transmission mechanism.