JP2003098420A - Optical element driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device having high detection precision of the forward/ backward movement position of an optical element of an optical element driving device which is driven by an electromagnetic actuator to move forward and backward. SOLUTION: The device is equipped with a CCD holder 14, a guide shaft 8 which supports the CCD holder 14 slidably along an optical axis O, and a VCM (voice coil motor) for driving a CCD which is so constituted that the center of a generated driving force shifts from the optical axis O toward the guide shaft 8 according to the arrangement position of a magnet 16 fixed to the CCD holder 14 across a yoke.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element driving device, and more particularly to an optical element driving device for driving an optical element holding member forward and backward by an electromagnetic actuator.

[0002]

2. Description of the Related Art Conventionally, various lens barrels having a built-in optical element driving device for driving a lens, which is an optical element, or an image pickup element back and forth, using an electromagnetic actuator such as a VCM (voice coil motor) as a drive source, have been proposed. Has been done. For example, the lens barrel disclosed in Japanese Patent Laid-Open No. 4-86714 has a fixed portion for driving the lens inside the barrel and a movable portion that is a part of the lens holding frame, and is made of a magnetic material. The drive source is a VCM that is composed of a curved yoke portion and a coil portion. It also has a built-in position detection sensor for detecting the lens position.

As another conventional example, a lens barrel for focusing by advancing and retracting the image pickup element in the optical axis direction has already been proposed. In this lens barrel, the sleeve portion of the image pickup element holding frame is fitted on the shaft to slidably hold the holding frame. A flexible circuit board (hereinafter, referred to as FPC) is applied as an electrical connection to the movable side of the lens barrel for driving the image pickup device.

[0004]

In the above-mentioned conventional optical element driving device and the like, since the magnets serving as thrust generating sources are arranged substantially symmetrically in the vertical and horizontal directions about the optical axis, The center of the driving thrust is at the center of the optical axis of the lens. However, the lens holding member is driven with the sleeve fitted in the guide shaft as a fulcrum, so that the distance between the action point and the fulcrum is large, and the twisting phenomenon occurs at the fulcrum portion.

If there is looseness in the shaft and the sleeve, V
The thrust of the CM causes the movable frame of the holding member to tilt about the axis. The amount of deviation in the fc (focus adjustment) direction due to this inclination differs between the center of the optical axis and the position detection sensor unit, which causes the hysteresis of the drive characteristics.

Further, in a conventional lens barrel for focusing by advancing / retreating an image pickup device in the optical axis direction, when an inclination of the image pickup device holding frame occurs due to backlash between the shaft and the sleeve, an image pickup caused by this tilt is taken. The eccentricity of the image plane of the element directly appears as a shake of the image.

Further, in the above-mentioned conventional example, when the FPC is electrically connected to the image pickup device, the force generated by the bending of the FPC hinders smooth driving of the image pickup device. However, the accuracy of the advance / retreat position was reduced.

The present invention has been made in order to solve the above-mentioned problems, and one of the objects thereof is to improve the detection accuracy of the advance / retreat position of the optical element of an optical element driving apparatus which is driven forward / backward by an electromagnetic actuator. It is to provide an expensive device.

Another object of the present invention is to provide an apparatus capable of reducing the fluctuation of the image forming plane of the image pickup element of the optical element driving apparatus as much as possible.

Still another object of the present invention is to provide an apparatus having a structure in which fluctuations in load due to bending of an FPC acting when an image pickup element of an optical element driving device moves back and forth are small.

[0011]

A first optical element driving device of the present invention comprises an optical element holding member, a guide member for slidably supporting the optical element holding member in the optical axis direction, and an optical element holding member. An electromagnetic actuator for sliding the lens by electromagnetic drive and a position along the guide member of the optical element. The light emitting element and the light receiving element are When the position is displaced in the direction along the guide member, the position detecting means is arranged at a position that causes a displacement in the direction along the guide member that is substantially the same as the amount of displacement.

The second optical element driving device of the present invention includes an optical element holding member, a guide member for slidably supporting the optical element holding member in the optical axis direction, and a guide member for the optical element holding member. And an image pickup element held by the optical element holding member so that the image pickup surface is located at a position that bisects the sliding contact portion in the optical axis direction.

Further, according to the third optical element driving device of the present invention, the image pickup element holding member, the guide member for slidably supporting the image pickup element holding member, and the one end portion of the image pickup element holding member. It is supported and pulled out in a direction substantially orthogonal to the optical axis so that the load applied to the image sensor holding member does not change depending on the sliding direction of the image sensor holding member, and then bent so as to generate a biasing force toward the optical axis. A flexible circuit board for transmitting and receiving signals between the image pickup device and a predetermined electric circuit, the predetermined portion being supported by the fixed lens frame, is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 are exploded perspective views of a lens barrel applied to the image pickup apparatus according to the first embodiment of the present invention. FIG. 5 is a vertical sectional view of the lens barrel.

The lens barrel of the image pickup apparatus of this embodiment has four lens barrels.
A zoom lens barrel having a group configuration, in which zooming is performed by using a stepper (stepping motor) as a drive source and a cam ring 3
The lens group holding frame is moved back and forth by rotating. Focusing is performed by a CCD, which is an image sensor.
Is carried out by moving the CCD holder 14 itself, which holds C, to move back and forth by a VCM (voice coil motor) which is an electromagnetic actuator.

The present lens barrel has the above-mentioned perspective view,
As shown in the cross-sectional view and the like, the outer fixed frame 1 fixed to the camera body mainly via each fixed frame described later, and the first group lens 41.
And holds the cam ring 3 through the three cam followers 22a.
The first group frame 2 which is one of the lens holding frames having a so-called three-piece suspension structure, which can be freely moved back and forth by the cam grooves 3a, and the cam grooves 3a, 3b, 3c, 3d for driving the respective holding frames are arranged. A rotatable cam ring 3, a corrugated washer 4 for urging the cam ring, and an inner fixed frame 5 fixed to the outer fixed frame 1 are provided.
And have.

Further, the lens barrel holds guide shafts 7 and 8 for movably advancing and retracting each lens frame other than the first group frame 2 and the CCD holder 14, and the second group lens 42, and the guide shafts 7 and 8. 2 is a lens holding frame that is supported by 8 and can move back and forth.
Holding the group frame 9 and the third group lens 43, the guide shaft 7,
A third group frame 1 which is a lens holding frame which is supported by 8 and can freely move back and forth.
A fourth group frame 11 which is a lens holding frame which holds 0 and a fourth group lens 44 and is supported by the guide shafts 7 and 8
A yoke 12 which constitutes a VCM which is an electromagnetic actuator for driving a CCD, the guide shafts 7 and 8, a rear fixed frame 13 which supports the yoke 12, and the guide shafts 7 and 8.
CCD which is slidably supported by, is mounted with an LED 61 which is a light emitting element for detecting the advancing / retreating position, holds the CCD 55 and the LPF 54, and is wound with a drive coil 14b constituting a VCM for advancing / retreating itself. Holder 14,
A cam ring drive unit for driving the cam ring and the rear cover 15 for restricting the LPF 54, the CCD 55, the guide shafts 7 and 8 in the axial direction, and using the stepper 51 as a drive source. And a PSD 62 which is a position detecting means for detecting the advancing / retreating position of the CCD holder 14 and which is supported on the rear fixed frame 13 side, receives the light from the LED 61, and detects the position.

The outer fixed frame 1, the inner fixed frame 5, and the rear fixed frame 1
3 is integrally fixed with screws through the respective mounting holes 1a and 5a ', 5a and 13a in a state where the respective constituent members described below are incorporated. The relative positioning of the frames 1 and 13 in the rotational direction at the time of fixing is performed by fitting the positioning pins 1b and 13b into the positioning holes 5b of the inner fixed frame 5.

The first group frame 2 is inserted into the outer fixed frame 1 in such a manner that the first group frame 2 is restricted from rotating,
The rotation is restricted by inserting a boss 23 coaxially provided with the pin 22 of the first group frame 2 into the straight guide groove 1j arranged on the inner peripheral portion of the outer fixed frame 1 to restrict the rotation. To be done. Here, instead of the boss 23, a roller may be supported by the pin 22 and fitted into the straight guide groove 1j. The forward / backward drive of the first group frame 2 during zooming is performed by the rotation of a cam ring 3 described later.

Further, on the inner peripheral portion of the outer fixed frame 1, convex portions 1d and 1e which are linear reference guide portions are formed downward along the advancing / retreating direction.
However, linear projections 1f and 1g are provided on the upper side. Further, a leaf spring 21, which is a biasing member, is screwed to the mounting portion 1h in the opening 1i at the upper center. Even if the above-mentioned first group frame 2 is fitted in the convex portions 1d, 1e, 1f, 1g in a state where there is a fitting backlash required for mechanical or component precision, the first group frame 2 is downward. And the outer periphery thereof is in contact with the convex portions 1d and 1e. During the zooming operation, the first group frame 2 moves forward and backward in this state, and in the normal photographing state, this contact state is always maintained, and the first group lens 41 does not tilt with respect to the lens barrel optical axis O. become.

When an upward external force is applied to the first group frame 2, the outer periphery of the first group frame 2 only slightly moves until it comes into contact with the convex portions 1f and 1g.

The cam ring 3 is rotatably fitted in the inner peripheral portion of the first group frame 2, and further, the inner fixed frame 5 is fitted in the inner peripheral portion of the cam ring 3. However, a corrugated washer 4 is inserted on the outer periphery of the inner fixed frame 5, and the corrugated washer 4 has a flange portion 3h of the cam ring 3 and a flange portion 1c of the outer fixed frame 1.
Press so as to abut. Due to this pressing force, the above 1
The group frame 2 is positioned with respect to the inner and outer fixed frames 5 and 1 in the optical axis direction. Further, since the corrugated washer 4 is inserted with the groove 4a provided on the inner periphery thereof fitted in the convex portion 5e of the inner fixed frame 5, its rotation is restricted.

A gear portion 3i is provided along the outer periphery of the flange portion of the cam ring 3, and a drive gear 34a of a cam ring drive portion, which will be described later, meshes with the gear portion 3i through a groove 1m of the fixed frame 1. And the cam ring 3 is driven by the drive unit.
Is rotated from the wide position to the tele position.

The wide position is detected by a PI (photo interrupter) 53 in which the shielding leaf portion 3j provided on the flange portion is arranged at a rotation position corresponding to the wide position on the rotation locus. It Positioning of each zooming position is performed on the basis of the wide position.

The protruding stopper 3k provided on the flange portion of the cam ring 3 is inserted into the groove portion 1k provided on the flange portion 1c of the outer fixed frame 1, and the wide end of the cam ring 3 is Alternatively, it acts as a rotation stopper at the tele end.

There are three first-group-frame cam grooves 3a provided on the outer periphery of the cam ring 3, and the cam followers 22a of the first-group frame 2 are slidably fitted therein. The first group frame 2
Is restricted in its rotation, and when the cam ring 3 rotates, it moves back and forth in the optical axis O direction.

Further, cam grooves 3b, 3c and 3d for the second, third and fourth group frames are provided on the inner peripheral portion of the cam ring 3, and the second, third and fourth group frames 9, 10, 11 are respectively provided. The cam followers 9c, 10c, 11c fixed to the above are slidably fitted. When the cam ring 3 rotates, the holding frames move to the optical axis O.
It will move back and forth in the direction.

The cam ring drive section uses the stepper 51 as a drive source, and the rotation of the output gear thereof is transmitted to the drive gear 34a via the gear train and further transmitted to the gear section 3i of the cam ring 3. To be done.

The support structure for the guide shafts 7 and 8 is as follows.
In front of the guide shafts 7 and 8 on the inner fixed frame 5 (subject side)
Support holes 5f and 5g for supporting the end of the
The ends of the guide shafts 7 and 8 are inserted therein, the radial direction is positioned, and further, the subject side direction is restricted in the optical axis direction.

The approximately middle portion of the guide shafts 7 and 8 is supported by the axial holes 13f and 13g of the rear fixing frame 13 in a state of being positioned in the radial direction. The positions of the shaft hole 13f and the shaft hole 13g in the optical axis direction are shifted so as to be convenient because of the support structure of the lens holding frame and the CCD holder, as will be described later. Forward,
That is, it is located on the subject side. After the CCD holder 14 is inserted, the rear (CCD side) end portions of the guide shafts 7 and 8 are attached to the rear fixing frame 13 by the bottomed holes 15f and 15g of the rear cover 15 and the optical axes. The direction is regulated and held down.

The guide shafts 7 and 8 slidably support the second group frame 9, the third group frame 10 and the fourth group frame 11 between the inner fixed frame 5 and the rear fixed frame 13. That is, the guide shaft 7 has a forked portion 9f of the second group frame 9, a third group frame 10, and a shaft hole portion 10 of the fourth group frame 11.
f and 11f are fitted. The guide shaft 8 has a shaft hole portion 9g of the second group frame 9, a third group frame 10, and a forked portion 10g, 11 of the fourth group frame 11.
g is fitted, and the frames 9, 10 and 11 are slidably supported in a state of being housed inside the inner fixed frame 5.

Then, as described above, the cam followers 9c, 1 fixed to the second, third, fourth group frames 9, 10, 11 are attached.
0c and 11c are openings 5c and 5d, which will be described later, of the inner fixed frame 5.
To be slidably fitted into the cam grooves 3b, 3c, 3d of the cam ring 3. The escape of the followers 9c, 10c, 11c, and the guide shafts 7, 8 and the frames 2, 3, 4 group 9,
The inner fixing frame 5 is provided with the openings 5c and 5d along the optical axis O in order to allow the shaft holes 10 and 11 to escape, and the CCD holder 14 is rear-fixed. The guide shafts 7 and 8 supported by the shaft holes 13f and 13g of the frame 13 are slidably inserted by being inserted from the non-subject side, that is, the CCD side. In the fitted state, the drive coil 14b is
Is inserted forward through the opening 13h, and the yoke 12
It is located in a portion surrounded by the inner peripheral portion 12b and the magnet 16. After that, the rear cover 15 is attached to the rear of the rear fixed frame 13, and the guide shafts 7 and 8 are fixed by the rear cover 15.
The position is regulated in the optical axis direction.

On the other hand, as described above, the above-mentioned fourth group frame 11 is mounted on the subject side of the rear fixed frame 13, that is, on the front side, and the length of the fourth group frame 11 in the optical axis direction is on the guide shaft 7 side. Has a relatively long shaft hole 11f, and a bifurcated portion 11g having a relatively short length in the optical axis direction of the fourth group frame 11 is fitted on the guide shaft 8 side. In addition, the shaft hole 13f of the rear fixing frame 13,
As for the disposition position of 13g, as described above, the shaft hole 1f into which the guide shaft 7 is inserted is closer to the shaft hole 13f into which the guide shaft 8 is inserted.
It is located rearward of 3 g along the optical axis direction.

When the CCD holder 14 is attached to the guide shafts 7 and 8, the length of the holder 14 in the optical axis direction may be relatively short in terms of holding accuracy.
On the side of the guide shaft 7 supported by f, a shaft hole 14g that needs to have a relatively long length in the optical axis direction in terms of holding accuracy is formed in the shaft hole 1
They are inserted through the guide shaft 8 side supported by 3 g.

The yoke 12 constituting the VCM is made of a magnetic material and is fixed to the subject side of the rear fixing frame 13 through the mounting holes 12a by mounting holes 13c and 13d.

FIG. 7 is a sectional view around the yoke portion of FIG.
(A) is a sectional view orthogonal to the optical axis, and (B) is its C-C.
FIG. As shown in the figure, the yoke 12 has a yoke inner peripheral portion 12b, and four magnets 16 are mounted on the top, bottom, left and right so as to face the inner peripheral portion 12b. Those magnets 1
The width of 6 is set to about 3/5 of one side of the yoke inner peripheral portion 12b, but not limited to this size, an appropriate size may be adopted so as to satisfy various conditions.

The magnets 16 disposed above and below the magnet 16 are attached along the horizontal scanning direction of the CCD 55,
Further, the magnets 16 disposed on the left and right are CCDs.
It is attached along the vertical scanning direction 55. Further, the magnet 16 arranged in the horizontal direction is attached to the right side of the optical axis O, and the magnet 16 arranged in the vertical direction is attached to the lower side of the optical axis O. Further, in the present embodiment, the four magnets 16 are arranged symmetrically with respect to the substantially diagonal line Lc passing through the optical axis O of the inner peripheral portion 12b of the yoke 12. The arrangement state of the magnet 16 is determined in relation to the positions of the shaft hole 14g portion and the bifurcated portion 14f portion of the holder 14 as described later. Therefore, the above four magnets 1
The arrangement of 6 is not necessarily limited to the above arrangement.

As shown in FIG. 5 and the like, an LPF (low pass filter) 54 and a CCD 55 are mounted on the CCD holder 14 from the rear side, that is, from the CCD side. Furthermore, the C
The drive coil 14b is provided on the outer periphery of the cylindrical portion outside the LPF54 mounting portion of the CD holder 14 so as to surround the LPF54.
It is wound around the bobbin of the CD holder 14.

In the sectional view around the yoke portion shown in FIG. 6A, the relative arrangement positional relationship between the yoke 12 and the guide shafts 8 and 7 as seen from the CCD side is shown. As shown in this figure, the guide shaft 8 insertion shaft hole 14g portion of the holder 14 and the guide shaft 7 supporting bifurcated portion 14f portion are located in the gap between the positions where the magnets 16 are arranged, and the light of the yoke 12 portion is There are a lower right position and an upper left position on a substantially diagonal line Lc passing through the axis O. Therefore, the center line connecting the guide shafts 8 and 7 and the diagonal line Lc on the inner circumference of the yoke substantially coincide with each other.

The LED 61 of the light emitting element and the PS of the light receiving element which constitute the advancing / retreating position detecting portion (position detecting means) of the CCD 55.
As shown in FIGS. 7 and 8, the arrangement state of the D (light position detecting element) 62 is arranged on the side of the center line Lc connecting the guide shafts 7 and 8, which will be described later in detail.

The CCD holder 14 and the CCD 55 are also provided.
As for the relative position of the CCD holder 14 in the optical axis direction, as shown in the operation diagram of the CCD holder in the tilted state of FIG. 10 and the optical axis direction sectional view around the CCD holder of FIG. On the vertical line passing through the center point 14i of the sleeve 14h length of the 14g portion, the image plane 55 of the CCD 55
It is arranged so that a is located.

Further, as shown in the sectional view of FIG. 11, the FPC 56 for electrical signal connection, one end of which is fixed to the CCD 55, is attached so as to extend in a direction substantially orthogonal to the optical axis O and to be attached to the rear fixing frame. It is led out from the opening 13i of 13 and fixed near the opening 13i. then,
With the FPC 56 bent, the CCD holder 14 is
A pressing force FF for pressing in the optical axis direction is always applied.

Among the lens barrel of the present embodiment having the above-mentioned configuration, the optical element driving device section, in particular, the configuration and operation thereof will be described in detail.

First, the state in which the thrust acts on the CCD holder 14 will be described. Since the CCD holder 14 is supported by the guide shafts 7 and 8 so as to be able to move forward and backward as described above, the drive constituting the VCM is driven. The thrust F (FIG. 6) is applied to the CCD holder 14 in the optical axis direction by the current flowing through the coil 14b.
(See (B)) occurs. By its thrust F, CCD
The holder 14 and hence the CCD 55 can be driven back and forth.

The point P1 at which the thrust F, which is the resultant force of the driving force acting on the CCD holder 14, acts on the magnet 16 as shown in FIG.
As described in (A) above, the optical axis is offset toward the lower right direction with respect to the optical axis O. In addition, since they are arranged symmetrically with respect to the diagonal line Lc, the point of action P1 is located on the substantially diagonal line Lc and closer to the guide shaft 8 insertion shaft hole 14g from the optical axis O. Become.

Here, the point of action P1 of the driving thrust F of the VCM will be specifically determined. As a conventional general example, FIG.
As shown in FIG. 3, considering a case where magnets 16A having a side length a are symmetrically arranged around the optical axis O around the inner circumference 12a of the yoke, thrusts in four directions are indicated by operating points in the figure. Work on Q0 (distance b). The resultant force of the four thrusts coincides with the optical axis O. Let the coordinates be (0, 0). If the thrust acting on each point b at that time is f / 4, the resultant thrust is f.

On the other hand, the CDD holder 14 of the present embodiment described above.
Considering the point of action P1 of the resultant force F of the thrust acting on the VCM, the width of each magnet 16 is a × 3, where the width of the yoke inner circumference 12a is a, as shown in the magnet arrangement diagram of FIG. Assuming / 5, thrust in four directions acts on the action point Q1 in the figure, and the distance is given by b or a / 5.

The coordinates of the optical axis O are (0, 0), and the center position P1 of the resultant force of each thrust is the coordinates (x, y). Considering the balance of moments, the following equation holds. That is, x
Regarding the direction, (f / 4) × (3/5) × ((a / 3) −x) + (f /
4) × (3/5) × (b−x) + (f / 4) × (3 /
5) × ((a / 5) −x) = (f / 4) × (3/5) ×
(B + x) holds. Therefore, the value of x is x = a / 10.

In the y direction, (f / 4) × (3/5) × (y + b) = (f / 4) ×
(3/5) x ((a / 5) -y) + (f / 4) x (3 /
5) × (by) + (f / 4) × (3/5) × (a / 5
-Y) is established. Therefore, the value of y is also y = a / 1.
It becomes 0.

Therefore, the shift amount OP1 of the point of application of the thrust F from the optical axis O in the direction of the guide axis 8 is determined by the dimension a = 10 mm, b.
= 6.8 mm, the deviation amount OP1 is 1.6 mm.

Since the thrust force F is located closer to the fitting shaft hole 14g portion in this way, compared to the arrangement structure of the magnet 16A which is not offset with respect to the optical axis O as shown in FIG.
The rotation moment acting on the shaft hole 14g portion that serves as the fulcrum of the holder 13 becomes smaller. In this way the CCD holder 1
If the rotational moment acting on 4 is small, the "twisting" phenomenon that occurs in the guide shaft 8 and the shaft hole 14g of the holder 14 is unlikely to occur, and a small thrust force enables smooth forward / backward drive.

Next, the light emitting element 61 and the PS constituting the advancing / retreating position detecting section (position detecting means) of the CCD 55 of the present embodiment.
The arrangement state and function of D62 will be described in detail.

FIG. 7 is a perspective view showing the arrangement of the CCD holder 14 and the advance / retreat position detecting portion, and FIG. 8 is the above-mentioned CCD.
It is the figure which looked at holder 14 and the circumference of an advance / retreat position detection part from the CCD side. As shown in the figure, the PSD 62 has its light-receiving surface 62a supported by the rear fixed frame 13 in a state of being positioned on a line that passes through the optical axis 0 and is orthogonal to the line Lc connecting the centers of the guide shafts 7 and 8. ing. The CCD holder 14 does not necessarily need to be integrally formed, but in the present embodiment, an integrally formed slit 14i is provided at a position facing the PSD 62.
At the end of i, an LED 61 is disposed so as to be supported by the CCD holder 14.

By arranging the position detecting portion as in the above-described embodiment, when the CCD holder 14 moves back and forth along the optical axis O by the thrust F, the CCD holder 14 is moved.
As shown in FIG. 9, even if the optical axis is tilted in the optical axis direction along the center line Lc by the gap of the guide shaft hole 14g, the movement amount D0 of the CCD 55 in the optical axis direction due to the tilt is
The PSD 62 detects the same movement amount. Therefore, the PSD 62 can accurately detect the forward / backward movement amount of the optical axis center including the movement amount due to the tilt of the CCD holder 14.

If, as shown in FIG. 18, the PSD 62A and the LED 61A of the position detecting portion are arranged above the CCD holder 14, CC as shown in the sectional view of FIG.
D holder 14 is driven by the above-mentioned thrust F and has a shaft hole for guide shaft 14g
If it falls by a certain amount of backlash, the CCD image plane plane optical axis center 5
5a fluctuates by the movement amount D0, but the PSD of the position detection unit
At the position of 62A, it is detected that the amplified amount D1 has changed, and the position detection accuracy is lowered.

In the structure of this embodiment, as described above, the magnet 16 is disposed substantially symmetrically with respect to the center line Lc connecting the guide shafts, and the driving thrust F acts on the center line Lc. It is considered that the CCD holder 14 rarely tilts in the direction around the line Lc. Therefore, the tilt direction of the CCD holder 14 is likely to fall in the optical axis direction along the center line Lc, and by arranging the position detecting unit as described above, highly accurate detection is performed. In addition, CCD
The proper arrangement position of the position detection unit considering that a force other than the driving thrust F acts on the holder 14 will be described later as a modified example.

Further, in the CCD holder 14 of this embodiment, as shown in FIGS. 10 and 11, it passes through the longitudinal center 14i of the sleeve portion 14h of the shaft hole 14g of the guide shaft 8 and is orthogonal to the shaft center. The image plane center 55a of the CCD 55 is located on the extension line. When the clearance between the sleeve portion 14h and the shaft of the shaft hole 14g is d and the clearance of the sleeve portion 14h is rattled by the driving thrust F, the center 5 of the image plane of the CCD 55
The amount of deviation δ0 between 5a and the optical axis O of the photographic lens system has a maximum value of d / 2, which is the minimum in principle. This deviation amount δ0 from the optical axis O has a great influence on the shake of the image pickup screen, and in the present embodiment, the shake of the image pickup screen is suppressed.

If the CCD shown in the state diagram of FIG.
The center 55a of the image plane of 55 is the center 14 of the sleeve portion 14h.
When it is arranged at a position deviated from i, the deviation amount δ between the image plane center 55a and the optical axis O of the taking lens system becomes the deviation amount δ2 in FIG. 20C when tilted in one direction. Although it becomes smaller as shown, when tilted in the other direction, a considerably large amount δ1 is given and the image shake becomes large as shown in FIG. Further, as shown in FIG. 20D, the center 55a of the image plane of the CCD 55 is placed on the sleeve portion 14h.
When it is largely displaced from the center 14i of the
Will become even larger.

The above-described support structure for the optical element holding member is particularly effective for the photographing element holding member. This is because in the case of holding the lens, the coma aberration is adversely affected by the amount of inclination with the optical axis itself, so there is a circumstance where it is desirable to make the length of the sleeve part as long as possible. This is because such an aberration does not occur, and the screen shake countermeasure can be considered as the highest priority.

Further, it is more effective when the holding member easily tilts with respect to the optical axis at the time of driving as in the present embodiment.

Further, in this embodiment, the CCD 55
As shown in FIG. 11, an electric signal connecting FPC 56 fixedly attached to the FPC 56 is arranged so as to extend in an upward direction orthogonal to the optical axis, and further, a pressing force F is applied along the extending direction via the FPC 56.
Since F is given to the CCD holder 14, the axial hole 14g of the CCD holder 14 keeps its upper surface unidirectionally in contact with the guide shaft 8 as shown in FIG. Therefore,
It is possible to reduce the hysteresis of the force applied to the holder 14 as the CCD 55 moves back and forth in the optical axis direction. In addition, as shown in FIG. 12, since the shaft hole 14g is in contact with the CCD 5,
The inclination of the image plane of No. 5 with respect to the optical axis O direction is unlikely to occur.

If the FPC for electrical signal connection fixed to the CCD 55 is used as in the conventional connection structure shown in FIG.
56A is folded back into a U shape and mounted, and the rear cover-1
If a mounting structure that is fixed to 5 is taken, CC
A pressing force in the forward direction always acts on the D holder 14 via the FPC 56A. Then, the shaft hole 1 of the CCD holder 14
4g is held tilted as shown in FIG.
The inclination accuracy of the image plane of No. 5 with respect to the optical axis O will be deteriorated.

A driving operation of the present lens barrel incorporating the above-described optical element driving device will be described.

First, when the power switch (not shown) is turned on, the stepper 51 is driven and the cam ring 3 is rotated to the wide end position which is the reset position, and 1, 2, 3, 4
The group frames 2, 9, 10, and 11 are moved to the wide end positions, respectively. When performing zooming, the stepper 51 is driven from the above state, the cam ring 3 is rotated, and 1, 2, 3, 4
The group frames 2, 9, 10, and 11 are moved in accordance with zooming. And VCM which is an electromagnetic actuator
C by controlling the current of the drive coil 14b of
The CCD 55 supported by the CD holder 14 is moved to follow the zoom tracking position which is the focus position corresponding to the zooming position. That is, the CCD 55 moves hourly according to the zooming operation in order to maintain the in-focus state.

When focusing is performed, the VCM
Thus, the CCD holder 14 is driven forward and backward, and the CCD 55 is moved to the in-focus position.

In the lens barrel of the present embodiment, the action point of the drive thrust F of the VCM is moved closer to the guide shaft 8 to cause the CCD holder 14 to be generated in the shaft 8 and the shaft hole 14g of the holder 14. The resistance force due to twisting can be reduced, and the drive thrust F can be effectively applied.

Further, even if the CCD holder 14 is slightly tilted when it is moved back and forth, the position detector can detect the forward / backward position including the tilted state, so that a highly accurate CC can be obtained.
Enables D drive.

Further, the fluctuation of the image plane of the CCD 55 due to the rattling of the shaft hole 14g for the guide shaft of the CCD holder 14 can be reduced as much as possible.

The FP acting when the CCD 55 moves forward and backward
Stable CC with little change in load due to bending of C56
The D holder 14 is configured to be supported by the guide shaft 8.

Next, the driving thrust F in the VCM of the optical element driving device incorporated in the lens barrel of this embodiment.
A first modified example in which the point of action of is closer to the guide shaft 8 than that of the above-described embodiment will be described.

FIG. 15 is a cross-sectional view of a cross section of the VCM of the first modified example, which is orthogonal to the optical axis around the yoke portion. As shown in this figure, two magnets 16B are mounted on the lower side and the right side so as to face the yoke inner peripheral portion 12b. The width of the magnets 16 is equal to the width of the yoke inner peripheral portion 12b. The two magnets 16B do not necessarily have to be symmetrically arranged with respect to the substantially diagonal line Lc passing through the optical axis O of the inner peripheral portion 12b of the yoke 12, but they are symmetrically arranged in this embodiment. The other structures are similar to those of the above embodiment.

In the VCM constructed as described above, the point of action P2 of the driving thrust is located closer to the guide shaft 8 than in the case of the above-described embodiment, and therefore the CCD holder 14 is slid by the prying when driving back and forth. There is little increase in dynamic resistance, and smooth forward / backward drive is performed.

A second modification of another VCM to be described next is that two magnets 16C and a direction opposite to those of the magnets 16C are set so that the action point P3 of the driving thrust is located at the center of the guide shaft 8. The two magnets 16D magnetized in the above are arranged in the yoke 12.

FIG. 16 is a cross-sectional view of a cross section of the VCM of the above modification, which is orthogonal to the optical axis around the yoke. Further, FIG. 17 is an action diagram of thrust seen from the surface along the diagonal line Lc in FIG. The two magnets 16C have the same size, magnetizing direction, and attachment position as the magnet 16B applied in the first modification, but the other two magnets 16D have narrow width dimensions and thus have the above-mentioned structure. As described above, the magnetizing direction is opposite to that of the magnet 16C. Also, one of the mounting positions is mounted from the upper left side in FIG. 16, and the other one is mounted on the upper left side.

Therefore, the thrusts F1 and F2 generated by the magnets 16C and 16D, respectively, are as shown in FIG.
A distance L1 from the guide shaft 8 and a distance L longer than the distance L1.
The two points are applied in alternate directions. Then, the moment generated by the thrust F1 and the thrust F2 is the guide shaft 8
The above distances L1 and L2 and the thrust forces F1 and F2 are set so as to balance with each other. That is, the distance and the thrust are set so that F1 * L1 = F2 * L2 holds. In this case, the thrust F acting on the CCD 14 is represented by F = F1 -F2.

According to this modification, since the moment that the CCD holder 14 is tilted around the guide shaft 8 due to the thrusts F1 and F2 generated in the VCM is 0,
The sleeve 14h, which is the shaft supporting portion of the CCD holder 14, does not cause "twisting", and smooth forward / backward drive is possible in a state where sliding resistance is low.

Next, a modified example of the CCD advancing / retreating position detecting section (position detecting means) of the optical system element driving device of this embodiment will be described.

In the above embodiment, only the driving thrust F of the VCM acts on the guide axis center line Lc, and the CCD holder 14 is tilted in the optical axis direction along the center line Lc. However, the bending force of the FPC 56, the frictional force of the shaft sleeve portion 14h of the CCD holder 14, the fitting backlash, and the like do not necessarily limit the tilting along the center line Lc.

Therefore, the advancing / retreating position detecting portion of the present modified example considers how the CCD holder 14 falls as described above, and
When the position of 55 in the direction of the optical axis is displaced in the direction along the guide axis, a PSD, which is an optical position detection element, is provided at a portion facing the position on the CCD holder 14 that gives a displacement amount substantially the same as the displacement amount. It is provided. In this case, the disposition position of the PSD passes through the optical axis O as in the above embodiment, but is not necessarily located on the extension line orthogonal to the center line Lc.

According to this modified example, the amount of movement of the CCD 55 in the optical axis direction in the optical axis direction is more accurately detected by the PSD while the influence of the tilt of the holder 14 is small.

[0082]

As described above, the optical element driving device of the present invention is a device for driving the optical element forward and backward by the electromagnetic actuator, and the optical element holding member slidably supported by the guide member has a sliding resistance. It is possible to smoothly move forward and backward with a small amount of force, and it is possible to suppress the required thrust of the electromagnetic actuator to a small extent. It is possible to detect the forward / backward position and perform the forward / backward drive with high accuracy.

[Brief description of drawings]

FIG. 1 is a part of an exploded perspective view of a lens barrel including an optical element driving device according to an embodiment of the present invention.

2 is a part of an exploded perspective view of the lens barrel of FIG.

FIG. 3 is a part of an exploded perspective view of the lens barrel of FIG.

4 is a part of an exploded perspective view of the lens barrel of FIG.

5 is a vertical cross-sectional view taken along the optical axis of the lens barrel of FIG.

FIG. 6 is a view showing V of the optical element driving device for the lens barrel of FIG.
FIG. 4A is a cross-sectional view of a CM around a yoke, where FIG. 7A is a cross-sectional view of a plane orthogonal to the optical axis, and FIG.

7 is a perspective view of a position detector of the optical element driving device for the lens barrel of FIG.

8 is a view of the position detecting portion of the optical element driving device of the lens barrel of FIG. 1 as viewed from the CCD side.

9 is a view of C of the optical element driving device for the lens barrel of FIG.
The figure which shows CCD displacement and the position detection state of the position detection part PSD when a CD holder is tilted only by backlash.

10 is a diagram showing the displacement of the image plane of the CCD when the CCD holder of the optical element driving device for the lens barrel of FIG. 1 is tilted.

11 is a sectional view around the CCD holder of the optical element driving device for the lens barrel of FIG.

12 is a cross-sectional view showing an operating state of a guide shaft support portion of a CCD holder of the optical element driving device for the lens barrel of FIG.

FIG. 13 is a diagram showing a state in which a magnet is attached to a yoke in a VCM of a general optical element driving device.

FIG. 14 is a view showing a mounting state of the VCM magnet on the yoke of the optical element driving device of the lens barrel of FIG. 1;

15 is a diagram showing a relative positional relationship between a magnet and a guide shaft, which is a modification of the VCM of the optical element driving device for the lens barrel of FIG. 1;

16 is a diagram showing a relative positional relationship between a magnet and a guide shaft, which shows another modification of the VCM of the optical element driving device for the lens barrel of FIG.

FIG. 17 is a diagram showing a state in which the thrust force of the VCM of the modified example of FIG. 16 is applied.

FIG. 18 is a view of the position detection unit in the conventional optical element driving device as viewed from the direction of the optical axis.

FIG. 19 is a diagram showing a difference between the displacement amount of the CCD and the detection amount of the position detection unit when the CCD holder in the optical element driving device of FIG.

FIG. 20 shows (A), (B), (C), and (D) the states of shaking of the CCD image pickup surface when the CCD holder in the conventional optical element driving device is tilted by a certain amount.

FIG. 21 is a vertical sectional view of a CCD holder in a conventional optical element driving device.

FIG. 22 is a view showing a state of the guide shaft support portion in a state in which the CCD holder of the optical element driving device is tilted by an amount corresponding to the play.

[Explanation of symbols]

8 …………………… Guide shaft (guide member) 12 …………………… Yoke (electromagnetic actuator) 13 …………………… Rear fixed frame (fixed mirror frame) 14 …………………… CCD holder (Optical element holding member) 16 ………………………… Magnet (electromagnetic actuator) 16B ……………… Magnet (electromagnetic actuator) 16C ……………… Magnet (electromagnetic actuator) 55 …………………… CCD (optical element) 56 …………………… FPC (flexible circuit board) 61 …………………… LED (light emitting element, position detection means) 62 …………………… PSD (light receiving element, position detecting means)

Claims (3)

[Claims] 1. An optical element holding member, a guide member for slidably supporting the optical element holding member in the optical axis direction, an electromagnetic actuator for sliding the optical element holding member by electromagnetic driving, and an optical element Detects the position along the guide member, and when the light-emitting element and the light-receiving element are deviated in the optical axis center position due to the tilt of the optical axis of the optical element, the deviation amount An optical element driving device comprising: a position detecting unit disposed at a position that causes a deviation in a direction substantially the same as the guide member. 2. An optical element holding member, a guide member that slidably supports the optical element holding member in the optical axis direction, and a sliding contact portion between the optical element holding member and the guide member is substantially equal to the optical axis direction. An optical element driving device comprising: an image pickup element held by an optical element holding member so that an image pickup surface is located at a dividing position. 3. An image pickup device holding member, a guide member for slidably supporting the image pickup device holding member in an optical axis direction, one end of which is supported by the image pickup device holding member, and a sliding direction of the image pickup device holding member. The image pickup element holding member is pulled out in a direction substantially orthogonal to the optical axis so that the load applied to the image pickup element holding member does not fluctuate, and then is bent to generate a biasing force toward the optical axis and a predetermined portion is supported by a fixed lens frame. An optical element driving device comprising: a flexible circuit board for transmitting and receiving a signal between the element and a predetermined electric circuit.