JP2003195144A - Lens drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens drive unit which has a small hysteresis and hardly gives rise to an image fluctuation. <P>SOLUTION: The lens drive unit, in which guide pins 1 and 2 which guide a lens holding frame 3 holding a lens glass 4 to the optical axis direction, a lead screw 15 which is rotated by a driving source 13 for moving the lens holding frame to an optical axis direction, a sleeve 5 which is formed integrally in the optical axis direction of the lens holding frame, a clamper 6 which is housed in the sleeve, and a rack gear 25 intermeshed with the screw are integrally formed has a contact portion 12 for transmitting the driving force in the optical axis direction with respect to the lens holding frame when the lead screw rotates and a spring 16 which energizes the rack gear of the clamper in a direction intermeshed with the lead screw. The clamper is guided movably in the optical axis direction and freely rotatably around the axes of the guide pins by means of the guide pins. The sleeve formed integrally with the lens holding frame is brought into proximity to the rotating axis direction of the lead screw by means of the clamper. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens driving device for moving a lens ball in a lens barrel for changing a magnification and focusing in a photographing lens such as a video camera or a digital still camera. .

[0002]

2. Description of the Related Art Video cameras and the like have become remarkably widespread due to miniaturization and weight reduction, high magnification, and multi-functionality. The autofocus mechanism in the shooting lens for the video camera uses the contrast of the light passing through the shooting optical system as C
There is an autofocus mechanism that measures the light by a CD (solid-state image pickup device) and determines the focus when the contrast value reaches a peak. This is a method in which a focus lens is driven by an actuator according to an instruction from a distance measuring device to perform a focusing operation.

In particular, in the contrast detection type autofocus mechanism, the combination with the inner focus optical system in pursuit of downsizing the optical system has been increasing. For example, as one method,
No. 27099 can be mentioned.

Here, the technique disclosed in Japanese Patent Publication No. 7-27099 is introduced as FIG. Although not shown here, the lens barrel body is a rear-focus zoom lens having an optical system built therein.

In FIG. 9, reference numeral 30 denotes a focus lens holding frame (hereinafter referred to as a lens holding frame) which is a lens holding member, and a lower side one side portion (sleeve portion) 30a is provided with a through hole (not shown). And is fitted with a guide shaft 31 which is parallel to the optical axis. 32 is the guide shaft 3 described above.
As in the case of 1, the lens holding frame 30 has a guide shaft parallel to the optical axis and the U-shaped groove 30b provided on the other side.
The movement in the rotation direction of is regulated.

Reference numeral 45 is a clamper which meshes with a lead screw 35 which is a screw shaft for outputting the rotation of the motor 36. G is held by the lens holding frame 30 described above by a focusing lens.

The clamper 45 is made of, for example, a material having excellent slidability such as polyacetal resin, and first and second holes 46 and 47 are formed on the upper side thereof. The guide shaft 31 described above is fitted to 46 and 47. Further, a concave portion 48 is provided on the upper side of the clamper 45, and the concave portion 48 is formed in a size and shape that fits in the thickness direction of the lower side one side portion 30 a of the lens holding frame 30. There is.

The clamper 45 is provided with first and second extension portions 49 and 51 and a third extension portion 53 having a spring property, and the above-mentioned first and second extension portions 49 and 51. 51
Rack gears 50 and 52 are provided on the front end side of the lead screw 3 and the rack gears 50 and 52, respectively.
It meshes with the 5 screws.

The rack gears 50, 52 provided at the tips of the first and second extension parts described above have a third extension having a spring characteristic so that the lead gears 35 and the rack gears 50 are surely engaged with each other. The size and shape of the part 53 are determined.

In the configuration of FIG. 9, the lead screw 35 and the rack gears 50 and 52 meshing with the lead screw 35 are in the same plane, but the sleeve 30a (lens frame 30) that moves due to the degree of blurring is It is not in the same plane but is formed at a position separated from it.

The lens driving device constructed as described above operates as follows. That is, CC not shown
The so-called autofocus device (not shown) and the motor 36, which detect the degree of blurring of the image formed on D and instruct rotation of the focus lens drive motor according to the degree of blurring,
It is connected by the connector 40 and the harness 39.

Here, when the degree of blurring is detected by the autofocus distance measuring device, the lead screw 35 of the motor 36 is rotated by the instructed rotation amount. When the rack gear parts 50 and 52 engaged with the lead screw 35 move in the axial direction, the clamper 45, which is sleeve-fitted to the guide shaft 31 arranged in parallel with the lead screw 35, moves in parallel with the optical axis. To do. Further, since the lens holding frame 30 is fitted by the guide shaft 31 and the sleeve 30a formed integrally with the lens holding frame 30, and is sandwiched by the concave portion 48 of the clamper 45, it is parallel to the optical axis. Can move in any direction without play.

On the other hand, the lens holding frame 30 has a U
Since the movement in the rotational direction is restricted by the character-shaped groove portion 30b and the guide shaft 32, the focus adjustment lens G attached to the lens holding frame 30 moves in the optical axis direction when the clamper 45 moves in the optical axis direction. It will move.
At this time, the rack gear parts 50 and 52 and the lead screw 35
Since they are pressed against each other by the third extension portion 53, they can engage with each other without backlash.

Further, since the clamper 45 is movably engaged with the guide shaft 31 in the optical axis direction, even if the parallelism between the guide shaft 31 and the lead screw 35 is slightly deviated, the clamper 45 moves the guide shaft 31. By rotating to the center,
It is possible to prevent the occurrence of troubles during movement such as catching.

Another example is Japanese Patent No. 28906.
No. 89 can be mentioned. Here, this patent 28th
The technology described in 90689 is introduced as FIG.

In FIG. 10, the master lens 64 is
The lens frame 60 is held by a resin lens frame 60 by means of heat caulking or the like. The lens frame 60 is provided with a first and a second guide poles 6 disposed inside a fixed lens barrel (not shown).
It is held by 1, 62 so as to be slidable in the optical axis direction.
In addition, on the upper portion of the lens frame 60, a drive shaft 66 having a feed screw 66a formed on the shaft of the motor 65,
An extending portion 71, which is formed with a notched nut 70a that is screwed with a circumference of 120 ° and extends below a drive piece 70 described later.
A groove (not shown) into which the front end portion 71a of the above is inserted is provided. This groove is formed so that when the driving piece 70 is inserted into a groove (not shown) of the lens frame 60, there is no gap in the optical axis direction and a slight gap in the direction perpendicular to the optical axis. In addition, 63 is a lens holding frame.

Further, the drive piece 70 having the notch nut 70a slides on one end of the drive piece 70 in parallel with the drive shaft 66 and to the third guide pole 68 provided on the motor mounting body 69, and
A guide groove 70d is formed so as to be rotatably held, and an arm 70c for sandwiching the drive shaft 66 is formed on the upper side of the drive piece 70, so that the third guide pole 68 is fixed. As a fulcrum, the drive shaft 66
Notched nut 70a
And the feed screw 66a are screwed together without a gap. As a matter of course, a clearance for sliding is provided between the feed screw 66a and the notch nut 70a, and the arm 70c has a shape such that this clearance does not become larger than necessary. It is formed in.

Further, the drive piece 70 has an extending portion 71 extending downward (to the lens frame 60) formed integrally with the drive piece 70, and the tip of the extending portion 71 has the above-mentioned shape. A front end portion 71a for engaging with a groove (not shown) provided on the upper portion of the lens frame 60 is formed.

In the structure of FIG. 10, a notched nut 70a that meshes with the feed screw 66a of the drive shaft 66.
Is in the same plane, but the distal end portion 71a of the drive piece 70 that moves depending on the degree of blurring is not in the same plane and is formed at a position separated from it.

The lens moving device constructed as described above operates as follows. That is, when the degree of blurring is detected by an autofocus distance measuring device (not shown) and the motor 65 rotates by the instructed rotation amount, the drive shaft 66 having the feed screw 66a is pressed and urged to be screwed with a small clearance. The drive piece 70 having the notch nut 70a slides on the third guide pole 68 and moves in the optical axis direction. Then, the lens frame 60 engaged with the driving piece 70 correctly obtains a predetermined moving distance with respect to the rotation angle of the motor 65, and performs the focusing operation of the master lens 64. At this time, the notch nut 70a screwed onto the feed screw 66a is formed so that the contact portion with the feed screw 66a is only 120 ° with respect to the circumferential direction, and the resistance loss due to the contact is small, so that it can be smoothly performed. Moving.

[0021]

By the way, in a video camera or the like generally used outdoors, there is a clearance for sliding as described above between the guide member for regulating the posture of the clamper 45 and the clamper 45. The problem is that the attitude of the clamper 45 changes depending on the feed direction of the motor, and this attitude change causes hysteresis in the moving distance of the master lens group with respect to the rotation of the shaft of the motor, making the focusing operation unstable. was there.

That is, this point will be described with reference to FIG. 9 as a conventional example and also with reference to FIG.
In FIG. 11A, the clearance for sliding is provided between the guide pin 31 and the clamper 45, which is a connecting component integrally formed with the rack gear 52 screwed with the lead screw 35, as described above. It is provided.

Here, when the degree of blurring is detected by the autofocus distance measuring device, an instruction to rotate the lead screw 35 of the motor 36 by a predetermined rotation amount, that is, a positioning instruction to the lens frame 30 is issued. The lead screw 35 rotates in the counterclockwise direction, which is a predetermined direction, according to the instruction. However, FIG. 11 different from FIG. 11A described above depending on the degree of blurring or the like.
When the driving directions are different as in (B) and the rotation amounts are the same, the lens positions are different between the lead screw 35 and the rack gear 52 even if the rotation amount of the motor is the same.
A so-called hysteresis m will occur.

That is, in the conventional structure as described above, the driving piece or the like that moves depending on the degree of blur is not in the same plane as the lead screw and the rack gear or the like that meshes with the lead screw, and is located at a position separated from it. However, since these are assembled with a clearance, hysteresis m is generated.

Therefore, the hysteresis m is suppressed,
That is, in order to eliminate the above-mentioned change in posture of the connecting part, it is possible to reduce the play required for assembling the connecting part, or to apply a pressure in the axial direction with the pivot bearing. When the play required for assembling is reduced, the rotational shake of the lead screw 35 and the like is easily transmitted to the lens frame 30, and the imaging position fluctuates.
A new problem occurs that so-called image shake occurs.

[0026]

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and the invention according to claim 1 provides a lens holding frame 3 holding a lens ball 4, Two guide pins 1 and 2 for guiding the lens holding frame 3 in the optical axis direction, a lead screw 15 rotated by a drive source 13 for moving the lens holding frame 3 in the optical axis direction, and the lens. A sleeve 5 integrally formed in the optical axis direction of the holding frame 3 and a rack gear 25 that is housed in the sleeve 5 and meshes with the lead screw 15 are integrally formed, and the lead screw 15 is rotated. In this case, a clamper 6 having a contact portion 12 for transmitting the driving force in the optical axis direction to the lens holding frame 3,
And a spring 16 for urging the rack gear 25 of the clamper 6 in a direction to engage with the lead screw 15. The clamper 6 is moved by the one guide pin 2 in the optical axis direction and is rotated around the guide pin axis. In the lens driving device which is freely guided, the sleeve 5 integrally formed with the lens holding frame 3 is brought close to the rotation axis direction of the lead screw 15 via the clamper 6. Lens drive device.

According to a second aspect of the present invention, in the lens driving device according to the first aspect, a spring 16 for urging the rack gear 25 of the clamper 6 in a direction to engage the lead screw 15 is attached to the sleeve 5. It is characterized in that the spring 16 and the clamper 6 are brought into contact with each other within a plane including a meshing point between the lead screw 15 and the rack gear 25.

According to a third aspect of the present invention, in the lens driving device according to the first and second aspects, the contact point T between the spring 16 and the clamper 6 is a meshing point between the lead screw 15 and the rack gear 25, and It is characterized in that it is substantially perpendicular to a plane including the rotation axis of the lead screw 15 and the direction in which the rack gear 25 is pressed against the lead screw 15 is generally in the antigravity direction.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a lens driving device according to the present invention will be described below with reference to the accompanying drawings. In addition, the embodiment described below is a preferred specific example of the present invention, and thus various technically preferable limitations are given, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, the present invention is not limited to these modes.

FIG. 1 is a partially exploded perspective view showing an embodiment of the lens driving device according to the present invention, FIG. 2 is an exploded perspective view of the lens driving device according to the present invention, and FIG. 3 is a lens according to the present invention. FIG. 4 is a cross-sectional view showing the configuration of the main part of the drive device, FIG. 4 is an enlarged cross-sectional view of the main part of the drive part of the lens drive device according to the present invention, and FIG.
Is the positioning state (1) of the lens driving device according to the present invention.
6 is an explanatory view showing a positioning state (2) of the lens driving device according to the present invention, and FIG. 7 is an exploded perspective view showing another embodiment of the lens driving device according to the present invention. 8
[FIG. 8] is a cross-sectional view showing the main configuration of FIG. 7.

In FIGS. 1 and 2, reference numerals 1 and 2 denote guide pins 3 which are arranged parallel to the optical axis of a lens ball 4 which will be described later.
Is a lens holding frame held by the guide pins 1 and 2 and movable in the optical axis direction, and 4 is a lens ball held by the lens holding frame 3.

The lens holding frame 3 to which the above-mentioned lens balls 4 are attached has a support arm 3 extending to one side (guide pin 1 side).
a, a support arm 3b formed integrally with the support arm 3a and extending to the other side (the guide pin 2 side), and in the axial direction of the guide pin 2 and on the mounting side of the lens ball 4 described above. And a sleeve 5 extending in the opposite direction and integrally formed with the support arm 3b. A U-shaped groove 20 into which the guide pin 1 is inserted is formed at one end of the support arm 3a.

A substantially U-shaped bottomed storage portion 5a is formed in the sleeve 5, and through holes 21 and 22 for inserting the guide pin 2 are formed therein. Also,
On the outer side of the sleeve 5, a groove 1 for locking a spring 16 described later is provided.
7 is formed, and on the other hand, a protruding portion 18 is formed so as to protrude upward on the outer side opposite to the groove 17 for locking the spring 16. Reference numeral 19 is a U-shaped groove formed above the protruding portion 18 and into which the boss 12 of the clamper 6 described later is inserted, and 26 is an upper portion provided above the protruding portion 18.

Reference numeral 6 denotes a clamper having an outer shape which can be accommodated in the bottomed accommodating portion 5a with a clearance. The clamper 6 has a cylindrical portion 10 on the lower side and the cylindrical portion 10 It is generally formed from an upper portion 9 protruding upward on one side, and protruding portions 7 and 8 protruding upward from the cylindrical portion 10 described above. The interval between the upper portion 9 and the protrusions 7 and 8 is set to be slightly wider than the diameter of the lead screw 15 of the motor 13, which will be described later.

Further, the clamper 6 has through holes 23, 2 for the guide pin 2 which will be described later in the bottomed storage portion 5a.
When the guide pin 2 penetrates through the guide pin 4, the guide pin 2 is rotatably held by the guide pin 2 while moving in the optical axis direction.

A rack 25 having rack gears 25a and 25b on the side of the upper portion 9 facing the protruding portions 7 and 8.
And a boss 12 is formed on the upper portion 9 of the upper portion 9 opposite to the rack 25. The boss 12 has a bent portion 16b of a spring 16 described later.
A locking hole 12a is formed. In addition, the cylindrical portion 10
Through holes 23, 24 through which the above-mentioned guide pin 2 is inserted are formed in the longitudinal direction.

The spring 16 is formed in a substantially J-shape, and one end of the spring 16 is bent inward toward the inside 16a.
However, the other end is also formed with a bent portion 16b which is also slightly bent inward.

Reference numeral 13 denotes a motor which is a power source for rotationally driving a lead screw 15 which will be described later. Reference numeral 14 denotes a motor mount for mounting the above-mentioned motor 13.
Is a lead screw that is connected to the rotating shaft of the motor 13, and is installed substantially parallel to the guide pins 1 and 2.

Next, a method of assembling the lens driving device having the above-described structure will be described mainly with reference to FIG. First, the clamper 6 is stored in the storage portion 5a of the sleeve 5 from above. Accordingly, the through holes 21 and 22 provided in the sleeve 5 and the through holes 23 and 24 provided in the clamper 6 are substantially aligned with each other. Also, at this time,
Above the protrusion 18 provided on the sleeve 5, the U-shaped groove 1
Since the boss 12 formed on the upper portion 9 of the clamper 6 is easily accommodated in the U-shaped groove 19, the boss 12 is formed. The clearance between the boss 12 housed in the U-shaped groove 19 and the U-shaped groove 19 is 3 to 15 μm, which is suitable for smooth focusing adjustment described later.
It is set to a degree.

After that, the U-shaped groove 20 of the support arm 3a extending to one side of the lens holding frame 3 is inserted into the guide pin 1 arranged on a fixed lens barrel (not shown). Next, the sleeve 5 accommodating the clamper 6 is inserted into the guide pin 2 arranged on the fixed lens barrel (not shown) with the through hole 21 provided in the sleeve 5 on the front side.

At the time of this insertion, the through holes 21 and 22 provided in the sleeve 5 and the through holes 23 and 24 provided in the clamper 6 are arranged so that their hole positions substantially coincide with each other, as described above. The operation is relatively easy. In addition, the alignment of the guide pin 2 and the through hole 21
Since the guide pin 1 is inserted into the U-shaped groove 20 of the support arm 3a extending to one side of the lens holding frame 3, the guide pin 2 can be easily performed and the guide pin 2 can be formed through the through holes 21, 22 and the through hole 23. , 24 is smoothly inserted. FIG. 1 shows this state.

As described above, the clamper 6 is provided in the sleeve 5.
Then, the motor mounting body 14 to which the motor 13 is mounted is pushed down in the arrow direction so that the lead screw 15 is inserted between the upper portion 9 and the projecting portions 7 and 8 described above.

Thereafter, the bent portion 16a on one end side of the spring 16 is locked in the groove 17 for locking the spring 16 provided on the outer side of the sleeve 5, and then the bent portion 16b on the other end side of the spring 16 is locked. By attaching the spring 16 to the hole 12a of the boss 12, the attachment of the spring 16 to the sleeve 5 is completed. FIG. 3 shows this state, and FIG. 4 shows the driving portion of FIG.

By mounting the spring 16 in this way, a pressing force in the direction of the arrow is applied to the clamper 6 in FIGS. 3 and 4. As a result, the lead screw 15 mounted between the rack 25 formed on the clamper 6 and the projecting portions 7 and 8 is coupled to the rack 25 with an appropriate pressing force applied. That is, the rack 25
The rack gears 25a and 25b and the lead screw 15 are engaged with each other without any play.

Further, the lead screw 15, a clamper 6 having a rack 25 that meshes with the lead screw 15, and a sleeve 5 having a protrusion 18 provided with a U-shaped groove 19 for engaging with the boss 12 of the clamper 6 (lens holding frame 3 ) And the like are assembled so that they are positioned so as to be in the same plane with each other.

Further, since the contact points of the spring 16 for pressing the rack 25 against the lead screw 15 are assembled in a substantially straight line in FIG. 4, a frictional force is generated with respect to the guide shaft. Therefore, the driving load is reduced.

By completing the assembling in this way, the lens holding frame 3 is supported movably in the optical axis direction by using the guide pins 1 and 2 as guides.

The focusing operation according to this embodiment will be described with reference to FIG. When the degree of blurring is detected by the autofocus distance measuring device and an instruction to rotate the lead screw 15 of the motor 13 by a predetermined rotation amount, that is, a positioning instruction to the lens holding frame 3, is issued, the lead screw 15 gives an instruction. Therefore, it rotates in a predetermined direction, for example, counterclockwise as shown in FIG.

In the case of FIG. 6 in which the amount of rotation is the same as in FIG. 5 but the driving direction is different depending on the degree of blurring and the like, the clamper 6 and the sleeve 5 are assembled with a clearance. However, since the lead screw 15, the clamper 6, and the sleeve 5 are assembled so that their respective members are in the same plane as described above, no hysteresis occurs and they are formed integrally with the rotary shaft of the motor 13. The lead screw 15 rotates,
A driving force in the biaxial directions of the guide pins is generated in the clamper 6 through the rack 25 that meshes with the lead screw 15. The driving force is transmitted to the lens holding frame 3 by the contact between the boss 12 of the clamper 6 and the groove 19 of the protruding portion 18 of the sleeve 5, and the lens holding frame 3 can be driven.

The clamper 6 together with the holding frame 3 guide pin 2
In order to smoothly move upward, the diameter of the guide pin through holes 23, 24 of the clamper 6 is 10 times larger than the diameter of the guide pin 2.
It is necessary to make it large by about μm. Therefore, the clamper 6
Although the attitude slightly changes with respect to the guide pin 2, in the present embodiment, the contact between the clamper 6 and the lens holding frame 3 is within a plane including the rotation axis of the lead screw 15.
Also, the lead screw 15 and the rack gears 25a and 25b
Since it occurs near the meshing point with the lead screw 15
The positional relationship between the engagement points of the rack gears 25a and 25b and the lens holding frame 3 in the optical axis direction is not affected by the fluctuation of the posture of the clamper 6, and the forward and backward movement of the teeth of the lead screw 15 is faithfully transmitted to the lens holding frame 3. Can be done.

FIG. 4 shows this state. If the width of the U-shaped groove 19 is too large with respect to the width of the boss 12, it causes hysteresis, but it is possible to set the gap to 3 μm or more and 15 μm or less with almost no influence on the cost, and 3 μm or more and 15 μm or less. Since the play of is small compared with the stepping amount of the step motor, it does not cause harmful hysteresis. In addition, 3 μm or more and 15 μm or less is within the range of the depth of focus and does not pose any problem in practical use.

Further, the rack gears 25a, 2 of the clamper 6
A spring 16 for urging 5b in a direction in which it engages with the lead screw 15 is attached to the sleeve 5 (lens holding frame 3), and the contact point between the spring 16 and the clamper 6 is the engagement point between the lead screw 15 and the rack gears 25a and 25b. Since it is in a plane including the rotation axis of the lead screw 15, the biasing force of the spring 16 is accurately transmitted to the rack gears 25a and 25b and the lead screw 15, so that the guide pin through holes 23 and 24 of the clamper 6 and the guide pin 2 are formed. There is no reaction force or surplus force between them and friction. Therefore, no load is applied to the driving of the lens holding frame 3 (sleeve 5).

Further, as shown in FIG. 4, two convex curved surfaces 26a, 2 having cross sections in the width direction of the groove of the lens holding frame 3 face each other.
With 6b, the contact area between the boss 12 of the clamper 6 and the groove 19 of the lens holding frame 3 becomes small, and it is difficult to transmit the shake of the clamper 6 to the lens holding frame 3 (sleeve 5). Further, even if an impact is applied to the lens holding frame 3, the extra force of the impact force in the guide pin axial direction is transmitted from the boss 12 of the clamper 6 to the groove 19 of the sleeve 5 (lens holding frame 3). Since the contact surfaces of both the boss 12 and the U-shaped groove 19 are substantially cylindrical, it is difficult to be crushed and the initial performance can be maintained.

FIG. 7 and FIG. 8 are a perspective view of a lens driving device according to another embodiment and a cross-sectional view showing the main structure of FIG.
This is the lens drive device of FIGS. 1 and 2 assembled by changing the mounting position of the sleeve 5 by 90 °.

Due to a manufacturing error, the lead screw 15 is shaken at the time of rotation, and the clamper 6 meshing with the lead screw 15 is shaken. On the other hand, in order for the lens holding frame 3 to move smoothly on the guide pins 1 and 2, a gap of several μm must be provided between the guide pin through holes 23 and 24 of the lens holding frame 3 and the guide pin 2. There is. Therefore, if the fluctuation of the clamper 6 is transmitted to the lens holding frame 3 holding the lens, the light rays passing through the lens ball 4 fluctuate, which is a main cause of so-called image shake.

However, in the present embodiment, the direction in which the rack gears 25a and 25b of the clamper 6 are in pressure contact with the lead screw 15 is approximately the antigravity direction, so that the reaction force in which the rack gears 25a and 25b of the clamper 6 are in pressure contact with the lead screw 15 is used. A force in the direction of gravity is constantly generated in the lens holding frame 3, particularly in the sleeve portion 5. Since the change in the posture of the clamper 6 is transmitted to the lens holding frame 3 as a variation of the reaction force in the direction of gravity, the posture of the lens holding frame 3 which is originally stable due to its own weight does not change, and image shake occurs. It becomes difficult.

[0057]

According to the first aspect of the invention, the lens holding frame holding the lens balls, the two guide pins for guiding the lens holding frame in the optical axis direction, and the lens holding frame moved in the optical axis direction. A lead screw rotated by a drive source to achieve the above, a sleeve integrally formed in the optical axis direction of the lens holding frame, and a rack gear that is housed in the sleeve and meshes with the lead screw. When the lead screw is rotated, a clamper having a contact portion for transmitting a driving force in the optical axis direction to the lens holding frame and a rack gear of the clamper are urged in a direction to mesh with the lead screw. And a spring for rotating the lens, wherein the clamper is guided by the guide pin so as to be movable in the optical axis direction and rotatable about the guide pin axis. And a sleeve formed integrally with the lens holding frame is brought close to the lead screw rotation axis direction via the clamper, so that the hysteresis is small and the amount of the lens driving device is stable. Can be provided.

According to a second aspect of the present invention, in the lens driving device according to the first aspect, the spring for urging the rack gear of the clamper in the direction of meshing with the lead screw is:
Since the spring is attached to the lens holding frame and the contact between the spring and the clamper is performed within a plane including the meshing point of the lead screw and the rack gear, the hysteresis is small and the amount is stable, and It is possible to provide a lens driving device with a reduced driving load.

According to a third aspect of the present invention, in the lens driving device according to the first and second aspects, the contact point between the spring and the clamper is the meshing point between the lead screw and the rack gear and the rotation of the lead screw. A lens drive that is substantially perpendicular to the plane including the axis and that the direction in which the rack gear is in pressure contact with the lead screw is approximately in the antigravity direction so that the hysteresis is small, the amount is stable, and the image shake is small. A device can be provided.

[Brief description of drawings]

FIG. 1 is a partially exploded perspective view showing an embodiment of a lens driving device according to the present invention.

FIG. 2 is an exploded perspective view of a lens driving device according to the present invention.

FIG. 3 is a cross-sectional view showing a main configuration of a lens driving device according to the present invention.

FIG. 4 is an enlarged cross-sectional view of a main part of a driving portion of the lens driving device according to the present invention.

FIG. 5 is an explanatory diagram showing a positioning state (1) of the lens driving device according to the present invention.

FIG. 6 is an explanatory diagram showing a positioning state (2) of the lens driving device according to the present invention.

FIG. 7 is a perspective view showing another embodiment of the lens driving device according to the present invention.

8 is a cross-sectional view showing the configuration of the main part of FIG.

FIG. 9 is a perspective view showing a main configuration of a conventional lens driving device.

FIG. 10 is a perspective view showing a main part configuration of another conventional lens driving device.

FIG. 11 is an explanatory diagram schematically showing a state of occurrence of hysteresis in FIG.

[Explanation of symbols]

1, 2 guide pin 3 lens holding frame 3a Support arm 3b support arm 4 lens balls 5 sleeve 5a storage 6 clamper 7 rigid body 8 rigid body 9 Upper part 10 Cylindrical part 11 12 Boss 12a Locking hole 13 motor 14 Motor mount 15 lead screw 16 spring 16a Bent part 16b tip 17 Locking groove 18 Projection 19 U-shaped groove 20 U-shaped groove 21 through hole 22 through hole 23 Through hole 24 through holes 25 racks 25a rack gear 25b rack gear 26 Upper part 26a curved surface 26b curved surface T contact point

Claims (3)

[Claims] 1. A lens holding frame that holds lens balls, two guide pins that guide the lens holding frame in the optical axis direction, and a drive source that rotates the lens holding frame in the optical axis direction. Lead screw, a sleeve integrally formed in the optical axis direction of the lens holding frame, and a rack gear that is housed in the sleeve and meshes with the lead screw are integrally formed, and the lead screw rotates. And a spring for urging the rack gear of the clamper in a direction in which the rack gear of the clamper meshes with the lead screw. Is a lens driving device which is guided by the guide pin so as to be movable in the optical axis direction and rotatable about the guide pin axis. A lens driving device characterized in that the sleeve integrally formed with a holding frame is brought close to the lead screw in the rotation axis direction via the clamper. 2. A spring for urging the rack gear of the clamper in a direction in which it engages with the lead screw is attached to the lens holding frame, and the spring and the clamper are brought into contact with each other at a meshing point between the lead screw and the rack gear. The lens driving device according to claim 1, wherein the lens driving device is configured to be performed in a plane including the lens. 3. A contact point between the spring and the clamper is substantially perpendicular to a plane including a meshing point between the lead screw and the rack gear and a rotation axis of the lead screw, and a direction in which the rack gear is pressed against the lead screw. 3. The lens drive device according to claim 1, wherein the lens drive device is configured so as to have a substantially anti-gravity direction.