JP2001042195A - Lens driving device and optical equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive plural movable lenses by utilizing the driving force of one driving source and to make a device compact by making entire length and projection area in an optical axis direction small. SOLUTION: This lens driving device for driving plural movable lenses 1 and 2 constituting an optical system in the optical axis direction is provided with a main driving screw shaft 11 rotationally driven by the driving source 10 and driving either lens 1 of the plural lenses 1 and 2 in the optical axis direction, and a driven screw shaft 14 rotationally driven by receiving the driving force from the shaft 11 and driving the other lens of the plural lenses 1 and 2 in the optical axis direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for driving a movable lens such as a lens in an image pickup apparatus such as a video camera and other optical apparatuses.

[0002]

2. Description of the Related Art As a zoom lens barrel for a video camera, for example, there is a zoom lens barrel composed of four lens groups of a fixed convex, a movable concave, a fixed convex, and a movable convex in order from the subject side.

FIGS. 5A and 5B show a lens barrel structure of a general zoom lens having a four-group lens structure. (B) shows a cross section taken along line AA in (A).

[0004] The four lens groups 201a to 201d forming the zoom lens barrel include a fixed front lens 201.
a, a variator lens group 201b that performs a zooming operation by moving along the optical axis, a fixed afocal lens 201c, and a focal plane maintenance and focusing during zooming by moving along the optical axis. And a forcing lens group 201d.

The guide bars 203, 204a, and 204b are arranged in parallel with the optical axis 205, and guide and stop the moving lens group. The DC motor 206 is a driving source for moving the variator lens group 201b.

The front lens 201a is held by the front lens barrel 202, and the variator lens group 201b is
It is held at 1. Also, the afocal lens 201
c denotes an intermediate frame 215 and a focusing lens group 201d.
Are held by the RR moving ring 214.

The front lens barrel 202 is positioned and fixed to a rear lens barrel 216. A guide bar 203 is positioned and supported by the two lens barrels 202 and 216, and a guide screw shaft 208 is rotatably supported. I have.
The guide screw shaft 208 is driven to rotate by the rotation of the output shaft 206 a of the DC motor 206 being transmitted through a gear train 207.

A V-moving ring 211 for holding the variator lens group 201b includes a pressing spring 209 and the pressing spring 20.
And a ball 210 which engages with a screw groove 208a formed in the guide screw shaft 208 by a force of 9 by the DC motor 206.
By being driven to rotate, 8 moves forward and backward in the optical axis direction while being guided and regulated by the guide bar 203.

Guide bars 204a, 204 are provided on the rear barrel 216 and the intermediate frame 215 positioned in the rear barrel 216.
04b is fitted and supported. The RR moving ring 214 can advance and retreat in the optical axis direction while being guided and rotated by the guide bars 204a and 204b.

Guide bars 204a and 204 are provided on an RR moving ring 214 for holding the focusing lens group 201d.
b is formed with a sleeve portion that is slidably fitted to the RR moving ring 2 in the optical axis direction.
14 and are integrated with each other.

The stepping motor 212 rotationally drives a lead screw 212a formed integrally with its output shaft. The RR moving ring 21 is attached to the lead screw 212a.
The RR moving ring 214 moves in the optical axis direction while being guided by the guide bars 204a and 204b by the rotation of the lead screw 212a with the engagement of the rack 213 assembled to the rack 4.

As a drive source for the variator lens group, a stepping motor may be used in the same manner as the drive source for the focusing lens group.

The front lens barrel 202, the intermediate frame 215, and the rear lens barrel 216 form a lens barrel body that substantially accommodates a lens or the like.

When the lens group holding frame is moved by using such a stepping motor, after detecting that the holding frame is located at one reference position in the optical axis direction using a photo interrupter or the like, The absolute position of the holding frame is detected by continuously counting the number of drive pulses applied to the stepping motor.

FIG. 6 shows an electrical configuration of a camera body in a conventional imaging apparatus. In this figure, FIG.
The components of the lens barrel described in (1) are given the same reference numerals as in FIG.

Reference numeral 221 denotes a solid-state imaging device such as a CCD;
Denotes a drive mechanism of the variator lens group 201b, and includes a motor 206 (or a stepping motor), a gear train 207.
And a guide screw shaft 208 and the like.

Reference numeral 223 denotes a focusing lens group 201d.
And includes a stepping motor 212, a lead screw shaft 212a, a rack 213, and the like.

Reference numeral 224 denotes a drive mechanism of the diaphragm device 235 disposed between the variator lens group 201b and the afocal lens 201c.

Reference numeral 225 denotes a zoom encoder, and 227 denotes a focus encoder. Each of these encoders detects the absolute position of the variator lens group 201b and the focusing lens group 201d in the optical axis direction. When a DC motor is used as the variator drive source, an absolute position encoder such as a volume or a magnetic type is used.

When a stepping motor is used as a drive source, a method of continuously counting the number of operation pulses input to the stepping motor after arranging the holding frame at the reference position as described above is used. General.

Reference numeral 226 denotes a diaphragm encoder, which employs a method in which a Hall element is disposed inside a motor serving as a diaphragm driving source and which detects the rotational positional relationship between a rotor and a stator.

A CPU 232 controls the camera. A camera signal processing circuit 228 performs predetermined amplification, gamma correction, and the like on the output of the solid-state imaging device 221. The contrast signal of the video signal that has undergone these predetermined processes passes through the AE gate 229 and the AF gate 230. That is, the optimum signal extraction range for exposure determination and focusing is set by this gate in the entire screen. The size of this gate is variable,
There may be a case where a plurality is provided.

Reference numeral 231 denotes an AF signal processing circuit which processes an AF signal for AF (auto focus), and generates one or a plurality of outputs related to a high frequency component of a video signal. 233 is a zoom switch, and 234 is a zoom tracking memory. Zoom tracking memory 234
Stores information on the focusing lens position to be set in accordance with the subject distance and the variator lens position during zooming. Note that C is used as the zoom tracking memory.
The memory in the PU 232 may be used.

For example, the photographer sets the zoom switch 23
3 is operated, the CPU 232 determines the current variator as a detection result of the zoom encoder 225 so that the predetermined positional relationship between the variator lens and the focusing lens calculated based on the information of the zoom tracking memory 234 is maintained. The absolute position in the optical axis direction of the lens and the calculated position of the variator lens to be set, and the current absolute position of the focus lens in the optical axis direction as a detection result of the focus encoder 227 and the calculated focus lens should be set. The drive of the zoom drive mechanism 222 and the focussing drive mechanism 223 is controlled so that the positions match each other.

In the auto focus operation, the CPU 2 sets the output of the AF signal processing circuit 231 to a peak so that
Reference numeral 32 controls the driving of the focusing drive mechanism 223.

Further, in order to obtain an appropriate exposure, the CPU 2
Reference numeral 32 designates the average value of the output of the Y signal passing through the AE gate 229 as a predetermined value, and controls the drive of the aperture driving mechanism 224 so that the output of the aperture encoder 226 becomes the predetermined value, thereby controlling the aperture diameter.

[0027]

In recent years, there has been a demand for smaller and smaller photographic lenses. However, conventionally, the optical type most frequently used as a zoom lens for a video camera includes four lens groups of a fixed convex, a movable concave, a fixed convex, and a movable convex in order from the subject side. However, this optical type has a problem that the total length of the lens barrel holding the optical system becomes long because the front lens is fixed. Therefore, a collapsible lens barrel structure in which the position of the front lens is collapsed when stored, and a front lens position variable lens barrel structure in which the overall optical length is shortened at the Wide end have been proposed.

However, since the retractable lens barrel structure and the front lens position variable lens barrel structure use a helicoid or the like,
There is a problem that the lens barrel structure tends to be complicated and large, and the number of parts increases, which leads to an increase in cost.

Further, a configuration having a drive source for each of the movable lens groups is also conceivable. However, for example, when there are a total of three movable lens groups, a driving source such as three motors is required. For this reason, even if the overall length can be shortened, there is a disadvantage that the projection area of the lens barrel viewed from the optical axis direction becomes large, and the layout of the camera is disadvantageous in many cases.

Also, a structure not using three motors, for example, a structure in which a cam surface is formed on the end surface of the above-mentioned helicoid cylinder and two movable lens groups are driven by this cam surface, or a cam ring is used. In this case, it is possible to drive a plurality of lens groups by using two motors to drive three movable lens groups. However, in addition to the above-described problems such as a complicated structure, a problem also arises that the projection area of the lens barrel in the optical axis direction increases.

In view of the above, the present invention provides a compact lens driving device and an optical apparatus which can drive a plurality of movable lenses by using the driving force of one driving source, and have a small overall length and a small projected area in the optical axis direction. It is intended to be.

[0032]

In order to achieve the above object, according to the present invention, a lens driving device for driving a plurality of movable lenses constituting an optical system in a direction of an optical axis is rotationally driven by a driving source. A main drive screw shaft for driving any one of the plurality of movable lenses in the optical axis direction, and a driving force received from the main drive screw shaft for rotationally driving the other movable lens among the plurality of movable lenses; A driven screw shaft for driving the lens in the optical axis direction is provided.

More specifically, for example, the optical system has a front lens having a convex power and is movably disposed closest to the subject side, and an optical system has a concave power and is movably disposed behind the front lens. Having at least a variator lens, an afocal lens fixedly disposed behind the variator lens having a convex power, and a focusing lens movably disposed behind the afocal lens having a convex power. When configured, the front lens is driven by the main drive screw, and the variator lens is driven in the opposite direction to the variator lens by a driven screw shaft to which a driving force is transmitted from the main drive screw via a gear. To be configured.

This eliminates the need for a complicated mechanism such as using a cylindrical cam ring or a helicoid cylinder having a cam surface formed on the end surface of a helicoid, as in the conventional collapsible lens barrel structure or the variable front lens barrel structure. It is possible to drive a plurality of movable lenses in the optical axis direction by one drive source. In particular,
The driving force is transmitted from the main driving screw shaft to the driven screw shaft via a gear, and both screw shafts are rotated in opposite directions to each other. A mechanism for driving the lens in the other direction along the optical axis can be realized with a very simple structure.

Therefore, it is possible to realize a compact lens driving device and optical apparatus having a small overall length and a small projected area in the optical axis direction.

Further, in such a lens driving device, an adjusting means for adjusting the position of the driven screw shaft in the optical axis direction with respect to the main driving screw shaft may be provided.

Specifically, for example, the adjusting means is constituted by a holding member for rotatably holding the driven screw shaft and a feed screw for moving the holding member in the optical axis direction by rotation.

Thus, the position adjustment (for example, tracking adjustment for zooming) of the movable lens driven by the main drive screw shaft and the movable lens driven by the driven screw shaft can be easily performed.

In this case, it is necessary to make it possible to transmit the driving force from the main driving screw shaft to the driven screw shaft within the range of adjusting the position of the driven screw shaft in the optical axis direction by the adjusting means.

Specifically, driven by a main driving screw shaft, the driving gear (for example, a spur gear) whose axial position with respect to the main driving screw shaft is fixed, and movable in the optical axis direction together with the driven screw shaft. The driving force is transmitted between the two screw shafts by a driven gear (for example, a spur gear) that transmits the driving force received from the driving gear to the driven screw shaft, and the driven gear is positioned by the adjusting means. A configuration in which the meshing state with the drive gear is maintained within the adjustment range.

Thus, the movable function driven by the main drive screw shaft is performed only by adjusting the feed screw or the like without impairing the original function of transmitting the driving force from the main drive screw shaft to the driven screw shaft. The position of the movable lens driven by the lens and the driven screw shaft can be adjusted.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1A and 1B show the configuration of a zoom lens system suitable for implementing the present invention and used for a photographing apparatus such as a video camera or a still picture camera and other optical apparatuses. Is shown. In these figures, 1 is a front lens group having a convex power, 2 is a variator lens group having a concave power, 3 is an afocal lens group having a convex power, and 4 is a focusing lens group having a convex power. Reference numeral 5 denotes a fixed lens group, and reference numeral 6 denotes a CCD. FIG. 1A shows a wide state, and FIG. 1B shows a telephoto state.

As apparent from these figures, in this zoom lens system, not only the variator lens group 2 and the focusing lens group 4 but also the
The front lens group 1 also moves in the optical axis direction.

Reference numerals 7, 8, and 9 denote the movement trajectories of the front lens group 1, the variator lens group 2, and the focusing lens group 4 during zooming, respectively. The front lens group 1 and the variator lens group 2 are zoomed. (Moving trajectories 7, 8), and the moving trajectory 9 of the focusing lens group 4 changes its curve according to the subject distance.

The present invention can be applied to a zoom lens system having no fixed lens group 5.

As described above, by moving the front lens group 1 in accordance with zooming, it is possible to shorten the entire length of the lens particularly obtained at the wide end as compared with the front lens fixed type.

FIGS. 2 and 3 show a lens driving apparatus according to an embodiment of the present invention having the above-mentioned lens system.

In these figures, reference numeral 10 denotes a stepping motor, and 11 denotes a main drive screw shaft which serves as an output shaft of the stepping motor 10 and extends in the optical axis direction of the lens driving device. As shown in FIG. 3, a front lens holding frame 2 for holding the front lens group 2 is provided on the main drive screw shaft 11.
The female screw 16a of the rack 16, which is integrally attached to the optical axis 0 in the optical axis direction, is meshed. Reference numeral 12 denotes a drive gear provided near the end of the main drive screw shaft 12 so as to be integrally rotatable.

The front lens holding frame 20 is guided to move in the optical axis direction by fitting a sleeve (not shown) into a guide bar 22 extending in the optical axis direction.
Are engaged with the guide bar 23, whereby the guide bar 2
Two rotations are restricted.

The front lens holding frame 20 is provided with a light-shielding wall 20c for setting a reference position by a photo interrupter or the like.

Reference numeral 14 denotes a driven screw shaft extending in the optical axis direction, and both ends 14a and 14b are rotatably held by bearings 15a and 15b of a holding member 15, respectively. As shown in FIG. 3, the driven screw shaft 14 is engaged with a female screw portion 17a of a rack 17 that is integrally attached to a variator holding frame 21 that holds the variator lens group 2 in the optical axis direction.

The variator holding frame 21 is guided to move in the optical axis direction by fitting the sleeve portion 21a into a guide bar 24 extending in the optical axis direction.
Is engaged with the guide bar 25, whereby the guide bar 2
Four rotations are restricted.

The holding member 15 has a fixing member 18 such as a front lens barrel of a lens barrel on which the lens driving device is mounted.
A guide groove 15c is provided to be fitted with a guide rail (not shown) formed on the main shaft. The holding member 15 is movable with respect to the main drive screw shaft 11 together with the driven screw shaft 14 without play in the optical axis direction. It has become. Reference numeral 13 denotes a driven gear provided to be rotatable integrally with the driven screw shaft 14, and meshes with the drive gear 12.

For this reason, the stepping motor body 10
Is operated to rotate the main drive screw shaft 11, the rotation driving force of which is transmitted to the drive gear 12 and the driven gear 13
, And is driven to rotate in the opposite direction to the main drive screw shaft 11. When the main drive screw shaft 11 rotates, the rack 16 and the front lens holding frame 20 (that is, the front lens group 1) are driven in one direction in the optical axis direction, and the driven screw shaft 14 The rack 17 and the variator holding frame 21 (that is, the variator lens group 2) are driven in a direction opposite to the optical axis direction. Thus, the front lens group 1 and the variator lens group 2 can be driven on the movement trajectories 7 and 8 as shown in FIGS. 1 (a) and 1 (b).

Regarding the difference in the amount of movement between the front lens group 1 and the variator lens group 2, the pitches of the screw shafts 11 and 14 can be set differently, and the ratio of the number of teeth of the driving gear 12 and the driven gear 13 This can be handled by setting (reduction ratio).

As described above, according to the lens driving device of the present embodiment, a structure in which the cam surface is formed on the end surface of the helicoid cylinder and the two movable lens groups are driven by the cam surface,
Compared to a structure in which a plurality of lens groups are driven using a cam ring, the projected area in the optical axis direction is simpler and smaller, and the driving of the front lens group 1 and the variator lens group 2 by one stepping motor 10 in the optical axis direction. Can be performed.

Further, a female thread 15 d is formed in the bearing 15 b of the holding member 15.
5d is screwed with a feed screw 31 which is rotatably held on the fixed member 18 and held so as to be restricted in axial movement. Further, a coil spring 19 is disposed between the fixing member 18 and the bearing 15b on the feed screw 31 to prevent looseness between the female screw 15d and the feed screw 31.

When the feed screw 31 is rotated, the holding member 15 can be moved together with the driven screw shaft 14 in the optical axis direction with respect to the main drive screw shaft 11.
Thus, the positional relationship between the front lens group 1 and the variator lens group 2 in the optical axis direction can be adjusted, and tracking adjustment for zooming can be performed.

The width of the driving gear 12 and the driven gear 13 in the optical axis direction is determined by the length of the driven screw 1
In a range in which the position of the fourth gear 4 with respect to the main drive screw shaft 11 can be adjusted, the meshing state of the two gears 12 and 13 is set to be maintained. For this reason, the front lens group 1 and the variator lens group 2 can be connected only by adjusting the feed screw 31 without impairing the original function of transmitting the driving force from the main drive screw shaft 11 to the driven screw shaft 14. The positional relationship in the optical axis direction can be adjusted.

The lens driving device configured as described above is used for the lens barrel shown in FIG. In this figure, reference numeral 26 denotes an aperture unit disposed behind the variator holding frame 21, and reference numeral 27 denotes a fixed afocal holding frame which is disposed behind the aperture unit 26 and holds the afocal lens 3. 28 is disposed behind the afocal holding frame 27, and
Is a focus holding frame for holding.

The focus holding frame 28 is
When a is fitted to the guide bar 25, it is guided to move in the optical axis direction, and when the U groove 28b engages with the guide bar 24, rotation around the guide bar 25 is restricted.

A rack 34 is attached to the focus holding frame 28 integrally in the optical axis direction. The female screw portion 34 a of the rack 34 meshes with a screw shaft 33 as an output shaft of the stepping motor 32. For this reason, when the stepping motor 32 operates and the screw shaft 33 rotates, the focus holding frame 28 moves in the optical axis direction. The drive control of the stepping motor 32 is performed together with the drive control of the stepping motor 10, and the driving of the front lens group 1 and the variator lens group 2 shown in FIG.
The focus lens group 4 moves along a locus 9 with the movement along the locus 7 and 8 shown in FIG.

Reference numeral 29 denotes a rear fixed lens barrel that holds the guide bar, the infrared cut and low-pass filter 30, and the CCD 6 that is an image sensor.

In the lens barrel having such a configuration, two of the three movable lens groups (the front lens group 1 and the variator lens group 2) are driven to rotate by one stepping motor 10. Screw shaft 11,
14 drives the movable lens group (focus lens group 4) with the stepping motor 32.
Since the lens barrel is driven in the optical axis direction by the screw shaft 33 that is rotationally driven, the lens barrel structure can be simplified, and the projected area of the lens barrel in the optical axis direction can be reduced.

In this embodiment, the case where the stepping motor is used as the driving source has been described. However, a DC motor may be used as the driving source.

In the present embodiment, the case where the main drive screw shaft and the driven screw shaft are rotationally driven in directions opposite to each other to drive the movable lens group in the direction opposite to the optical axis direction has been described. The present invention can also be applied to a case where the main drive screw shaft and the driven screw shaft are rotationally driven in the same direction, and the case where the movable lens group is driven in the same direction.

Further, in the present embodiment, a case has been described in which the number of driven screw shafts driven and rotated by the driving force from the main driving screw shaft is one. The lens group may be driven.

[0068]

As described above, according to the present invention,
A main drive screw shaft that is rotationally driven by a drive source,
Each movable lens is driven in the optical axis direction by a driven screw shaft which is rotationally driven by receiving a driving force from the main driving screw shaft, so that the conventional collapsible lens barrel structure and the front lens position variable lens barrel are used. It is possible to drive multiple movable lenses in the optical axis direction with a single drive source without using a complicated mechanism, such as using a cylindrical cam ring or a helicoid cylinder with a cam surface formed on the end face of a helicoid like a structure. it can.

In particular, if a driving force is transmitted from the main driving screw shaft to the driven screw shaft via a gear and the two screw shafts are rotated in opposite directions to each other, one movable lens moves in one direction in the optical axis direction. A mechanism for driving the other movable lens in the other direction along the optical axis in accordance with the driving can be realized with a very simple structure.

Therefore, it is possible to realize a compact lens driving device and an optical apparatus having a small overall length and a small projected area in the optical axis direction.

Further, in such a lens driving device, if an adjusting means for adjusting the position of the driven screw shaft in the optical axis direction with respect to the main driving screw shaft is provided, the movable lens driven by the main driving screw shaft and the driven The position of the movable lens driven by the screw shaft can be easily adjusted.

In this case, if the driving force can be transmitted from the main driving screw shaft to the driven screw shaft within the range of adjusting the position of the driven screw shaft in the optical axis direction by the adjusting means, the main driving screw shaft can be transmitted. The drive lens is driven by the movable lens driven by the main drive screw shaft and the driven screw shaft only by adjusting the adjusting means such as the feed screw without impairing the original function of the device that transmits the driving force from the shaft to the driven screw shaft. The position of the movable lens can be adjusted.

The invention described above provides a lens barrel or the like having a movable lens which is provided separately from the main drive and driven screw shafts and is driven by a screw shaft which is rotationally driven by a drive source different from the drive source. This is effective for downsizing of the optical device. In other words, it is sufficient to use only two driving sources for the three movable lenses, and the projection area in the optical axis direction of the lens barrel or the like is smaller than when the cam barrel or the helicoid barrel is rotated to drive the lens. Can be reduced.

In particular, the optical system includes, in order from the object side, a front lens unit having a convex power, a variator lens unit having a concave power, a fixed afocal lens unit having a convex power, and a focusing unit having a convex power. When at least one of the lens groups is configured, one of the front lens and the variator lens is driven by the main drive screw, and the other is driven by the driven screw shaft, and the focusing lens group is driven by the other drive. If driven by a screw shaft that is rotated and driven by a source, it is possible to achieve overall compactness by shortening the overall length of a lens barrel and the like capable of zooming and focusing and reducing the projected area in the optical axis direction. Can be.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a zoom lens optical system suitable for implementing the present invention.

FIG. 2 is a configuration diagram of a driving portion of a lens driving device according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of the lens driving device.

FIG. 4 is a configuration diagram of a lens barrel including the lens driving device.

FIG. 5 is a cross-sectional view of a conventional lens barrel.

FIG. 6 is an electric circuit block diagram of a conventional lens barrel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front lens group 2 Variator lens group 3 Afocal lens group 4 Focusing lens group 5 Fixed lens group 6 CCD 7, 8, 9 Movement locus of lens 10, 32 Stepping motor 11 Main drive screw shaft 12 Drive gear 13 Follower gear 14 Driven screw shaft 15 holding member 16, 17, 34 rack 18 fixing member 19 coil spring 20 front lens holding frame 21 variator holding frame 22 to 25 guide bar 26 aperture unit 27 afocal holding frame 28 focus holding frame 29 rear fixed lens barrel 30 Filter 31 Feed screw 33 Screw shaft

Claims (15)

[Claims] 1. A lens driving device for driving a plurality of movable lenses constituting an optical system in an optical axis direction, wherein the lens driving device is rotationally driven by a driving source, and moves any one of the plurality of movable lenses in the optical axis direction. A main drive screw shaft to be driven, and a driven screw shaft driven to rotate by receiving a driving force from the main drive screw shaft and driving another movable lens of the plurality of movable lenses in the optical axis direction. A lens driving device. 2. The lens driving device according to claim 1, wherein the main driving screw shaft transmits driving force to the driven screw shaft via a gear. 3. The lens driving device according to claim 1, wherein the driven screw shaft is driven to rotate in a direction opposite to the main driving screw shaft. 4. The movable lens driven by the main drive screw shaft and the movable lens driven by the driven screw shaft are driven in directions opposite to each other. The lens driving device as described in the above. 5. The lens driving device according to claim 1, further comprising an adjusting unit configured to adjust a position of the driven screw shaft in the optical axis direction with respect to the main driving screw shaft. 6. The apparatus according to claim 1, wherein the adjusting means includes a holding member for rotatably holding the driven screw shaft, and a feed screw for moving the holding member in the optical axis direction by rotation. The lens driving device according to claim 5. 7. A driving force transmission from said main driving screw shaft to said driven screw shaft within a range of position adjustment of said driven screw shaft in the optical axis direction by said adjusting means. Or the lens driving device according to 6. 8. A drive gear driven by the main drive screw shaft and fixed in the optical axis direction with respect to the main drive screw shaft, and movable in the optical axis direction together with the driven screw shaft and received from the drive gear. And a driven gear for transmitting the driving force to the driven screw shaft.The driven gear maintains the meshing state with the drive gear within a position adjustment range of the driven screw shaft by the adjusting unit. The lens driving device according to claim 7, wherein: 9. The lens driving device according to claim 8, wherein the driving gear and the driven gear are spur gears. 10. The lens driving device according to claim 1, wherein the driving source is a stepping motor. 11. A motor, a main driving screw shaft as an output shaft of the motor, a driven screw shaft that is driven to rotate by a driving force from the main driving screw shaft,
A first rack holding a first movable lens that constitutes an optical system is mounted with a rack that meshes with the main drive screw shaft.
A holding member and a rack that meshes with the driven screw shaft are attached, and a second holding member that holds a second movable lens that constitutes an optical system is configured. By the rotation of the main drive screw shaft, A lens driving device, wherein the first holding member is driven in the optical axis direction, and the rotation of the driven screw shaft drives the second holding member in the optical axis direction. 12. A front lens having a convex power and movably disposed closest to the subject side, and a variator lens having a concave power and movably disposed behind the front lens. And an afocal lens having a convex power and fixedly arranged behind the variator lens,
It is configured to have at least a focusing lens movably disposed behind the afocal lens with a convex power, and one of the front lens and the variator lens is driven by the main drive screw, The lens driving device according to claim 1, wherein the other is driven by the driven screw shaft. 13. A movable lens which is provided separately from the main driving and driven screw shafts and is driven by a screw shaft which is rotationally driven by a driving source different from the driving source. 13. The lens barrel according to any one of to 12 above. 14. The optical system includes, in order from the object side, a front lens group having a convex power, a variator lens group having a concave power, a fixed afocal lens group having a convex power, and a convex power. A focusing lens group, and one of the front lens and the variator lens is driven by the main drive screw, and the other is driven by the driven screw shaft, and the focusing lens group is 2. The driving device according to claim 1, wherein the driving device is driven by a screw shaft that is rotated by another driving source.
4. The lens driving device according to 3. 15. An optical apparatus comprising the lens driving device according to claim 1. Description: