CN218917760U

CN218917760U - Lens driving device

Info

Publication number: CN218917760U
Application number: CN202220587101.3U
Authority: CN
Inventors: 陆圣
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-03-19
Filing date: 2022-03-17
Publication date: 2023-04-25
Anticipated expiration: 2032-03-17
Also published as: CN115113359A; CN112987223A; CN115016092A

Abstract

The utility model provides a lens driving device, which can include a lens driving device capable of adjusting focus by stretching and retracting a lens through an electromechanical conversion element, and is characterized by comprising a friction part for transmitting the movement of the electromechanical conversion element, wherein the friction part comprises a friction spring, a moving body and a friction driving shaft; the friction spring is fixed with the moving body integrally or directly used as the moving body, and the friction spring is combined with the friction driving shaft through friction; the electromechanical transducer driver is arranged such that the direction of expansion and contraction thereof is parallel or non-parallel to the optical axis of the lens.

Description

Lens driving device

Technical Field

The present utility model relates to a lens driving device, and more particularly to a lens driving device using an actuator using an electromechanical conversion element such as a piezoelectric element or a friction spring.

Background

Currently, cameras mounted on portable smart devices such as smart phones and smart watches are becoming more and more functional and higher in performance. And is particularly characterized in that the high pixel of the photosensitive chip and the corresponding lens have high performance. Although the pixel size of the photosensitive chip can be reduced to some extent by the manufacturing process to reduce the camera size, the reduction of the camera size has come close to the limit due to the limitation of the manufacturing process of the photosensitive chip and the lens. As a lens driver or motor for driving a lens, which occupies a certain volume of a camera, there are currently mainly a voice coil motor VCM and a piezoelectric ceramic driver motor. Voice Coil Motors (VCMs) are widely used because of their low cost and mature mass production. However, with the high pixelation of the mobile phone lens, the number of lenses of the optical lens matched with the mobile phone lens is developed to 6 to 9 or more, and the quality of the lens is heavier and heavier; and the travel requirements for the drive are also increasing due to the need for closer photography. Due to structural limitations, VCM has increasingly inadequate market development needs in terms of driving force and travel. The piezoelectric ceramic driver has the characteristics of large thrust, large stroke, small volume and the like. Therefore, it is a trend to adopt piezoelectric ceramic drivers for portable smart devices such as smart phones and smart watches in the future. The driving principle of the piezoelectric ceramic actuator and the conventional product structure technique are specifically described below.

The piezoelectric driving device is composed of a piezoelectric element, a counterweight (also called a weight) adhered and fixed at one end of the piezoelectric element, and a friction rod (friction driving shaft) adhered at the other end of the piezoelectric element. The driving principle is illustrated in fig. 1 as follows:

when a voltage having a saw-tooth waveform such as those shown in fig. 1, for example, between a-B and a B-C, is applied to a piezoelectric element of a piezoelectric driving apparatus, the piezoelectric element is extended in an axial direction against a slow rise portion (between a-B) and a drive shaft fixed to the piezoelectric element is moved together in a forward direction thereof. The moving body coupled to the driving shaft by friction moves together with the driving shaft.

When the voltage is in a steep drop (between B and C), the piezoelectric element is contracted by rapidly retracting along the axis, and the friction axis is displaced rapidly and backwardly together. At this time, as shown in fig. 1 (a 3), since the inertial force of the movable body is greater than the friction force generated with the drive shaft to generate sliding, the movable body is kept substantially at this position without moving. As a result, the amount of movement of the moving body in the forward direction is the difference between the amounts of movement at the time of forward and backward, compared with the initial state shown in fig. 1 (a 1). By repeating such application of a sawtooth voltage to the piezoelectric element to expand and contract, the movable body can be driven in the forward direction. If a reverse sawtooth voltage is applied, the back drive can be realized.

The following publications exist for the structural technical scheme of piezoelectric lens drivers for intelligent devices such as mobile phones:

reference 1: japanese patent (patent No. 5252260);

reference 2: japanese patent (patent No. 6024798).

Such an actuator drives a moving body using a laminated piezoelectric ceramic element as an electromechanical transducer element. For example, in an imaging device built in a mobile device such as a mobile phone, an electromechanical conversion driver of this type is used as a driving device for moving an optical lens in an optical axis direction to achieve miniaturization. A fixed body is bonded to one end of the piezoelectric ceramic element, a friction driving shaft body is fixed to the other end of the piezoelectric ceramic element, and the movable body and the friction driving shaft body are bonded to each other by friction.

In the driving device described in the above publication, the actuator is arranged in parallel with the optical axis of the optical lens, and the frame body supporting the optical lens is frictionally coupled to the friction driving shaft as a moving body, thereby moving the optical lens. In addition, in order to ensure frictional engagement with the friction rod, the movable body is pressed against the friction rod by the elastic force of the elastic body.

For example, as described in references 1 to 2, there is proposed a lens driving device in which a piezoelectric actuator is disposed in a corner (a) of a lens frame (or holder) in parallel with an optical axis of a lens, and a driving shaft (or rod) of the piezoelectric actuator is held between a V-shaped groove formed in the lens frame and a pressing rod supported by the lens frame and pressed by a cylindrical helical compression spring, thereby forming a friction joint. Fig. 2 to 4 are illustrations shown in reference 1. As shown in fig. 2-4, the piezoelectric drivers are disposed in parallel at a corner a in the same direction as the optical axis of the lens. Further, as shown in the bottom side views of fig. 2 to 4, the thickness of the piezoelectric lens actuator in the optical axis direction corresponds to the piezoelectric actuator length.

Further, reference 2 proposes a lens driving device in which a piezoelectric actuator is disposed at one corner of a lens frame in parallel with an optical axis, and friction coupling is formed by sandwiching a V-shaped planar groove formed in a lens frame and a driving shaft body of the piezoelectric actuator by a leaf spring supported by the lens frame and disposed along an outer periphery of the lens frame, as shown in fig. 5 to 6. The length of the piezoelectric actuator corresponds to the thickness of the lens driving device in the optical axis direction.

Since the drive shaft of the piezoelectric actuator, the piezoelectric element, and the weight are fixed in series, in the case of arranging the piezoelectric actuator parallel to the optical axis as described in

references

1 and 2, the series length of the piezoelectric actuator is limited, and the actuator thickness is not smaller than the series length. This is disadvantageous in the development of camera modules such as smartphones and smartwatches, which require further miniaturization and thinness.

Disclosure of Invention

In order to solve the above-described problems, the present utility model is a lens driving device for adjusting a focus by driving a lens with expansion and contraction of an electromechanical conversion element, wherein a friction spring is integrally fixed to a moving body or directly used as the moving body, and the friction spring and a friction driving shaft are frictionally coupled to each other, thereby realizing further miniaturization of the lens driving device using the electromechanical conversion element such as a piezoelectric element.

The purpose of the present utility model is to achieve further miniaturization of a lens driving device using an electromechanical conversion element such as a piezoelectric element with a simple structure.

The purpose of the present utility model is to achieve further miniaturization of a lens driving device driven by a piezoelectric element having a drive shaft-piezoelectric element-weight series-fixed structure with a low cost and a simple structure.

In order to achieve the above object, an embodiment of the present utility model provides a lens driving device, in which a lens is driven by expansion and contraction of an electromechanical conversion element to perform focus adjustment, and a friction spring is fixed to a moving body integrally or directly as a moving body, and the friction spring is coupled to a friction driving shaft by friction. In the lens driving device, a friction driving shaft body is fixed at one end of the electromechanical conversion element, and a fixed object is fixed at the other end.

Another embodiment of the present utility model provides a lens driving device that performs focus adjustment by driving a lens by stretching and retracting of an electromechanical conversion element, so that the stretching and retracting direction of the electromechanical conversion element is disposed to intersect with the optical axis of the lens, and further miniaturization can be achieved based on a friction spring scheme.

The electromechanical conversion element is arranged in such a manner that the expansion and contraction direction thereof is non-parallel to the optical axis of the lens, preferably in such a manner that the expansion and contraction direction thereof is orthogonal to the optical axis of the lens; the thickness direction reduction is most advantageous when the arrangement is in an orthogonal mode, and the effect is slightly worse when the non-parallel non-orthogonal mode is adopted than when the arrangement is in an orthogonal mode. Compared with the prior art, when the electromechanical conversion element is configured in a mode that the telescopic direction of the electromechanical conversion element is not parallel to the optical axis of the lens, the influence of the length dimension of the electromechanical conversion element on the thickness of the lens in the optical axis direction can be completely avoided or reduced, and the thickness of the lens module is further reduced.

The friction driving shaft body is combined with one end of the electromechanical conversion element, and the heavy hammer is combined with the other end of the electromechanical conversion element;

the lens driving device converts the movement of the electromechanical conversion element in the expansion and contraction direction into the movement of the lens in the optical axis direction by a conversion structure. The transformation structure includes:

a friction part formed by a spiral torsion friction spring in friction combination with the friction driving shaft and a moving body which covers the spiral torsion friction spring and moves together with the spiral torsion friction spring; the spiral torsion friction spring is fixed with the moving body covered on the spiral torsion friction spring into a whole, and the spiral torsion friction spring is combined with the friction driving shaft through friction; compared with the prior art, the arrangement scheme of the helical torsion friction spring can reduce the circumferential dimension of the lens module;

a conversion section that converts the movement of the electromechanical conversion element in the expansion and contraction direction into the movement of the lens optical axis direction, as a cam driving section or a cam driven section (as a cam driving section when the inclined surface moves in synchronization with the moving body and as a cam driven section when the inclined surface moves in synchronization with the lens frame) in synchronization with the moving body or with the lens frame (preferably integrally formed;

and an energizing spring part for energizing and pressing the driven part and the driving part all the time by the spring force of the spiral torsion energizing spring.

When the inclined surface moves synchronously with the moving body as the cam driving part, the inclined surface forms a certain angle relative to the extending and contracting direction of the electromechanical conversion element or the optical axis direction of the lens, and the inclined surface acts on the driven part which moves synchronously (preferably integrally) with the lens or the frame body thereof to drive the lens or the lens frame;

wherein when the inclined surface and the lens frame synchronously move to serve as a cam follower, a driving part on the moving body and the cam follower are contacted with each other, and the driving part presses the cam follower to drive the lens or the lens frame;

wherein the cam follower and the driving part are mutually pushed by the accumulated force of the energizing spring or the follower and the cam driving part are mutually pushed by the accumulated force of the energizing spring; preferably, the energizing portion of the energizing spring is substantially parallel to the inclined surface portion of the driven portion of the conversion structure.

Preferably, the electromechanical transducer element is a laminated piezoelectric element.

Another embodiment of the present utility model provides a lens driving device in which a moving body having a cam portion is frictionally coupled to the friction drive shaft, and movement of the moving body having the cam portion in a telescoping direction is converted into movement in an optical axis direction of a lens by movement of the moving body having the cam portion. In particular, the cam portion is a slope forming a predetermined angle with respect to the expansion and contraction direction of the electromechanical conversion element and the optical axis direction of the lens, and the cam slope as the driving portion acts on a pushing force of a driven portion integrally formed with a lens frame accommodating the lens, thereby driving the lens in the optical axis direction. In particular, the follower portion is configured to interact with the cam portion as the driving portion by the force of the energizing spring of the wound coil spring, and the straight arm of the energizing spring is substantially parallel to the cam slope.

Another embodiment of the present utility model provides a lens driving device in which a moving body having an active portion that converts movement in a telescopic direction of an electromechanical conversion element into movement in an optical axis direction of a lens is coupled to the friction driving shaft body by friction. In particular, the conversion structure includes a slope portion integrally formed with the lens frame and forming a predetermined angle with respect to the expansion and contraction direction of the electromechanical conversion element or the lens optical axis direction, and the driving portion and the driven portion of the movable body are in contact with each other. The lens is driven by the driving part pushing the passive body. In particular, the driven portion and the driving portion are energized and pressed against each other by an energizing spring, and the energizing portion of the energizing spring is substantially parallel to the inclined surface portion of the driven portion of the conversion structure.

Another embodiment of the present utility model provides a lens driving apparatus, wherein a friction driving rod is adhesively fixed at one end of the electromechanical conversion element, and a fixing body is fixed at the other end. The other feature is that a moving body having a cam is frictionally coupled to the friction drive rod to convert the movement of the electromechanical conversion element in the expansion and contraction direction into the movement of the lens in the optical axis direction. The cam is a slope forming a certain angle with respect to the expansion and contraction direction of the electromechanical conversion element and the optical axis direction of the lens, and is characterized in that the driven part integrally formed with the lens frame housing the lens is pressed to drive the lens. In the lens driving device, the follower portion is pressed against the cam surface by the spring member, and the pressing portion of the spring is substantially parallel to the cam surface.

The electromechanical transducer of the present utility model may be a piezoelectric element, preferably a laminated piezoelectric element, for example, a multilayer piezoelectric ceramic as a piezoelectric element.

It should be noted that the friction spring (wire spring/friction torsion spring/helical torsion friction spring) driving method of the present utility model can obviously reduce the circumferential or axial dimension of the lens module even if applied to a driving structure in which the extension and contraction direction of the electromechanical conversion element is parallel to the optical axis of the lens, as compared with the prior art (the driving connection method of the compression lever compression spring or the leaf spring of reference 1, reference 2. The crimping mechanism requires an additional width in the driving shaft direction, and the arrangement of the compression spring or the leaf spring in the circumferential direction also requires an additional space); in particular, in this configuration, a moving body fixedly connected with a friction spring can be omitted, so as to directly push a driven member such as a lens frame, and further compress the size.

The embodiment of the utility model has the following beneficial effects:

1. the friction fit of the wire spring (friction torsion spring/spiral torsion friction spring) and the contact area of the driving shaft are larger than that of the flat spring used in the prior art, so that the flat spring can be directly driven, and the sizes of the driving structure in the circumferential direction and the optical axis direction can be compressed.

2. The arrangement mode of the electromechanical conversion element is a mode that the extending and contracting direction of the electromechanical conversion element is non-parallel to the optical axis of the lens, preferably an orthogonal mode, and meanwhile, the cam mechanism is utilized to realize the power conversion of the direction, compared with the prior art, when the electromechanical conversion element is arranged in a mode that the extending and contracting direction of the electromechanical conversion element is non-parallel to the optical axis of the lens, the influence of the length dimension of the electromechanical conversion element on the thickness of the optical axis direction of the lens can be completely avoided or lightened, the thickness of the lens module is further reduced, and the miniaturized and thinned camera module is realized;

3. the contact area between the friction fit of the wire spring (friction torsion spring/spiral torsion friction spring) and the driving shaft is larger than that of the flat spring used in the prior art, so that abrasion caused by sliding friction is reduced, and the durability is improved;

4. the laminated piezoelectric element is used for driving, and meanwhile, the linear spring (friction torsion spring/helical torsion friction spring) is used for driving the moving body under the condition that the driving direction is not parallel to the optical axis direction, particularly orthogonal, so that compared with the prior art, the circumferential size of the lens module can be further reduced;

5. the pressing portion of the spring is substantially parallel to the cam surface, and the accuracy of lens drive control can be improved.

The advantages and spirit of the present utility model will be further understood from the following detailed description of the utility model and the accompanying drawings.

Drawings

FIG. 1 is a schematic diagram of a piezoelectric ceramic actuator in the prior art;

FIG. 2 is a front view of a piezoelectric actuator according to the prior art;

FIG. 3 is a perspective view of a piezoelectric actuator according to the prior art;

FIG. 4 is a bottom/side view of a piezoelectric actuator of the prior art;

FIG. 5 is an exploded view of a piezoelectric actuator of the prior art;

FIG. 6 is a two-dimensional view of a piezoelectric actuator according to the prior art;

fig. 7 is a perspective view showing the configuration of a lens driving apparatus according to an embodiment of the present utility model;

fig. 8 is an exploded view (exploded view of fig. 7) of the constitution of a lens driving apparatus according to an embodiment of the present utility model;

fig. 9 is a side view (left side view of fig. 11) of a configuration of a lens driving apparatus pertaining to an embodiment of the present utility model;

fig. 10 is a cross-sectional view of a piezoelectric driver section (D-D cross-sectional view of fig. 11) of a configuration of a lens driving device according to an embodiment of the present utility model;

fig. 11 is a front view of a configuration of a lens driving apparatus pertaining to an embodiment of the present utility model;

FIG. 12 is a cam portion operation view (C-C sectional view of FIG. 11) of a configuration of a lens driving device according to an embodiment of the present utility model; wherein, the liquid crystal display device comprises a liquid crystal display device,

(A) Indicating a starting position that has not been driven (long shot),

(B) A driving position indicating that the driving (close-up imaging) has been performed;

fig. 13 is a perspective view of a mobile body 501 having a cam driving portion 55 according to an embodiment of the present utility model;

fig. 14 is a driving voltage waveform of a lens driving apparatus according to an embodiment of the present utility model;

fig. 15 is a perspective view showing a configuration of a lens driving apparatus according to another embodiment of the present utility model;

fig. 16 is an exploded view (exploded view of fig. 15) showing the configuration of a lens driving device according to another embodiment of the present utility model;

fig. 17 is a side view (left side view in fig. 19) showing the configuration of a lens driving apparatus according to another embodiment of the present utility model;

fig. 18 is a cross-sectional view of a piezoelectric actuator section (D-D cross-sectional view in fig. 19) showing the configuration of a lens driving device according to another embodiment of the present utility model;

fig. 19 is a front view showing a configuration of a lens driving apparatus according to another embodiment of the present utility model;

fig. 20 is a cam portion operation diagram (C-C sectional view of fig. 19) showing the configuration of a lens driving device according to another embodiment of the present utility model; wherein, the liquid crystal display device comprises a liquid crystal display device,

(A) Indicating a starting position that has not been driven (long shot),

fig. 21 is a perspective view showing a mobile body 502 having an active portion 155 according to another embodiment of the present utility model;

fig. 22 is a perspective enlarged view of the cam follower portion 134 (cam slope) of embodiment 2;

fig. 23 is a diagram showing driving voltage waveforms of a lens driving device according to another embodiment of the present utility model.

FIG. 24 is a schematic view of a focusing anti-shake driving device (in the front and rear directions of the optical axis) according to another embodiment of the utility model

Description of symbols

A 10 lens holder, 11 image pickup element substrate joining section, 12 guide shaft holding section, 13 lens rotation restricting section, 14a, 14b drive shaft holding section, 15 moving body rotation restricting section, 16a, 16b piezoelectric actuator holding plate mounting section, 20 guide shaft, 30 lens frame, 31 lens housing section, 32 guide section, 33 rotation restricting section, 34 driven section, 134 cam driven section (cam slope), 40 piezoelectric actuator holding plate, 41a,41b mounting section, 42 piezoelectric actuator bonding section, 501 moving body (with cam), 502 moving body (with active piece, no cam) 51 fitting section, 52 friction spring housing section, 53 rotation restricting section, 54a, 54b friction spring contact section, 155 active section, 55 cam active section, 56 energized spring mounting section, 60 friction spring, 61, 62 arm section, 70 energized spring, 71, 72 energized spring arm, 135 energized torsion spring mounting section, 136 energized torsion spring contact section, a lens optical axis, L lens group, piezoelectric image sensor, CB element, PA actuator, P1S 2, S2 driving shaft W2, W2 driving shaft bonding section, W2 driving force bonding section, and W2 driving force bonding section,

2. The lens is used for the optical lens,

3Z shaft moving assembly

30. A lens carrier (Z-axis moved body), 31a Z axis through-holes a,

32 Z-axis coil spring (moving member) 32a Z-axis coil spring arm a,32b Z-axis coil spring arm b

331. Fitting part a

302. Axial fitting surfaces a,303 axial fitting surfaces b,

304. circumferential fitting surfaces a,305 circumferential fitting surfaces b,

4 XYZ axle drive assembly

431 The Z-axis SIDM is used to determine,

Detailed Description

Specific embodiments of the present utility model are described in detail below with reference to the accompanying drawings. However, the present utility model should be understood not to be limited to such an embodiment described below, and the technical idea of the present utility model may be implemented in combination with other known technologies or other technologies having the same functions as those of the known technologies.

In the following description of the specific embodiments, for the sake of clarity in explaining the structure and operation of the present utility model, description will be given by way of directional terms, but words of front, rear, left, right, outer, inner, outer, inner, axial, radial, etc. are words of convenience and are not to be construed as limiting terms.

Specific embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

An embodiment of the lens driving apparatus is described below with reference to fig. 7 to 14.

The lens holder 10 includes an image pickup element substrate joint portion 11 joined to the image sensor substrate CB to which the image sensor IS attached, a support portion 12 of a guide post 20 fixed and held in parallel with the optical axis (a), and a lens stopper portion 13 for preventing the lens frame 30 from rotating along the optical axis.

The lens frame 30 includes a lens barrel 31 for accommodating the lens group L, a guide portion 32 movably fitted to the guide post 20 in the optical axis direction, and a rotation restricting portion 33 movable in the optical axis direction and engaged with the lens restricting portion 13 for restricting rotation around the guide post 20 of the lens frame 30 and positioning the center of the image sensor IS in agreement with the optical axis of the lens group L.

In this way, the lens group L moves along the optical axis while keeping the center of the photosensitive chip IS aligned with the optical axis, and the distance from the photosensitive chip IS can be changed, so that even if the photographing distance IS changed, the focal position of the lens group L can be aligned with the image plane of the photosensitive chip IS.

The piezoelectric actuator PA is composed of a piezoelectric element, a drive shaft S adhesively fixed to the front end surface P1, a weight adhesively fixed to the rear end surface, and the like.

The rear end face W2 of the weight W of the piezoelectric actuator PA has a piezoelectric actuator holding plate 40 coupled and fixed thereto, and holding portions 41a,41b of the piezoelectric actuator holding plate 40 are fixed to the lens holder 10.

The piezoelectric element P expands and contracts in the front-rear direction (P1-P2) by an amount corresponding to the applied voltage, and the drive shaft S moves axially in response to the expansion and contraction of the piezoelectric element S.

The driving shaft S is made of a material having a small specific gravity (for example, carbon fiber resin), and the weight W is made of a material having a large specific gravity (for example, tungsten). Since the expansion and contraction of the piezoelectric element P is performed in a short time of several microseconds, the front end surface P1 side of the drive shaft S having a small binding weight and a small inertial mass is displaced, and the displacement of the rear end surface P2 side of the weight W having a large binding weight and a large inertial mass is suppressed.

Since both ends of the drive shaft S are held on the drive

shaft mounting portions

14a, 14b of the lens holder 10 so as to be movable in the axial direction, the piezoelectric actuator PA is mounted so as to be positioned such that the axis of the drive shaft is orthogonal to the optical axis.

The inner diameter is smaller than the outer diameter of the drive shaft S, a friction torsion spring 60 which is a wire spring is pressed into the drive shaft S and is friction fitted with each other, and a fitting portion 51 of a moving body 501 having a cam portion is fitted on the drive shaft S so as to be movable in the axial direction.

The movable body 501 has a friction torsion spring housing portion 52 covering the friction torsion spring 60 and friction torsion

spring arm portions

61, 62 of the friction torsion spring 60 respectively pressed against friction torsion

spring contact portions

54a, 54b. The friction

spring contact portions

54a and 54b are inclined surfaces having a certain angle with respect to the axial direction, and are biased by the friction torsion

spring arm portions

61 and 62 by the elastic force of the friction torsion spring 60, so that the movable body 501 and the friction torsion spring 60 can integrally move by receiving a certain friction force on the drive shaft S.

Further, since the contact area between the friction engagement of the wire spring (friction torsion spring) and the drive shaft is larger than that of the flat spring used in the conventional art, abrasion due to sliding friction is reduced, and durability is improved.

The movable body 501 has a rotation restricting portion 53, and by fitting with the cam member rotation restricting portion 15 of the lens holder 10, the movable body 501 can be moved in the axial direction of the drive shaft s while preventing rotation.

The movable body 501 includes a cam driving portion 55, and the driven portion 34 is biased by an energizing spring arm portion 72 of an energizing spring 70 attached to the energizing spring attachment portion 56, so that the driven portion 34 is always in force contact with the cam driving portion 55, and the lens frame 30 is movable in the optical axis direction (Z direction) in conjunction with the movement of the movable body 501 in the driving shaft S direction (Y direction).

When the voltage shown in fig. 14 is applied to the piezoelectric driver PA, the driving shaft S is displaced with a large acceleration due to the rapid extension (contraction) of the piezoelectric element P when the applied voltage is rapidly changed, so that the friction torsion spring 60 is easily slid, and the driving shaft S is less displaced with a high acceleration due to the slow extension (contraction) of the piezoelectric element P when the applied voltage is slowly changed, so that the friction torsion spring 60 becomes less easily slid.

As shown in fig. 12 (a) and (B), the cam driving portion 55 (inclined surface) is substantially parallel to the energizing spring arm portion 72, that is, the operating angle of the energizing spring 70 is hardly changed in the actuator driving operation, and therefore, the difference in driving force (the round trip difference) in the driving direction of the lens frame 30 can be reduced.

The voltage shown in fig. 14 is applied to the piezoelectric driver PA. When the applied voltage is changed sharply, the driving shaft S is displaced with a large acceleration, so that the friction torsion spring 60 is easily slid, and when the applied voltage is changed slowly, the driving shaft S is displaced with a small acceleration, so that the friction torsion spring 60 is not easily slid due to the slow extension (contraction) of the piezoelectric element P.

By using a round trip difference in displacement acceleration of the drive shaft S due to the applied voltage waveform, the movable body 501 movable integrally with the friction torsion spring 60 IS moved in a predetermined direction, and the lens frame 30 linked with the movable body 501 IS moved so that the distance of the lens group L with respect to the photosensitive chip IS can be changed.

For example, the lens group L is driven forward by repeatedly and rapidly raising and lowering the applied voltage as shown in the drawing (a), and the lens group L is driven backward by repeatedly and rapidly raising and lowering the applied voltage as shown in the drawing (b).

Hereinafter, another embodiment of the lens driving apparatus will be described with reference to fig. 15 to 23.

As shown in fig. 15, 16, and 20, the lens holder 10 includes an image pickup element substrate joint portion 11 joined to the image sensor substrate CB to which the image sensor IS attached, a support portion 12 of a guide post 20 fixed and held parallel to the optical axis (a), and a lens stopper portion 13 for preventing the lens frame 30 from rotating along the optical axis.

Since both ends of the drive shaft S are held on the drive

shaft mounting portions

The inner diameter is smaller than the outer diameter of the drive shaft S, a coil spring type friction torsion spring 60 which is a coil spring is pressed into the drive shaft S and is friction fitted with each other, and the fitting portion 51 of the moving body 502 is fitted on the drive shaft S so as to be movable in the axial direction.

As shown in fig. 17, 18, 19, 20, 21, the movable body 502 having the driving portion 155 has a friction torsion spring housing portion 52 covering the friction torsion spring 60 and friction torsion

spring arm portions

61, 62 of the friction torsion spring 60 respectively pressed against the friction torsion

spring contact portions

54a, 54b. The friction

spring contact portions

spring arm portions

61 and 62 by the elastic force of the friction torsion spring 60, so that the movable body 502 and the friction torsion spring 60 can be integrally moved by receiving a certain friction force on the drive shaft S.

The movable body 502 has a rotation restricting portion 53, and by fitting with the movable body rotation restricting portion 15 of the lens holder 10, the movable body 502 can be moved in the axial direction of the drive shaft s while preventing rotation.

The movable body 502 includes a driving portion 155, and contacts with a cam follower portion (inclined surface) 134 integrally formed with the lens frame. The energizing spring 70 is mounted to the energizing torsion spring mounting portion 135, and the

arms

72 and 71 of the energizing spring are mounted to and press-contacted with the driving portion 155 and the energizing torsion spring contact portion 136 integrally formed with the lens frame 30, respectively. The urging spring 70 urges the driving portion 155 and the cam follower portion (inclined surface) 134 to force the cam follower portion (134) against the driving portion 155 on the movable body 502, so that the lens frame 30 can move in the optical axis direction (Z direction) in conjunction with the movement of the movable body 502 in the driving axis S direction (Y direction).

When the voltage shown in fig. 22 is applied to the piezoelectric driver PA, the driving shaft S is displaced with a large acceleration due to the rapid extension (contraction) of the piezoelectric element P when the applied voltage is rapidly changed, so that the friction torsion spring 60 is easily slid, and the driving shaft S is less displaced with a high acceleration due to the slow extension (contraction) of the piezoelectric element P when the applied voltage is slowly changed, so that the friction torsion spring 60 becomes less easily slid.

As shown in fig. 20 (a) and (B), the cam follower (inclined surface) 134 is substantially parallel to the arm 72 of the energizing torsion spring, that is, the operation angle of the energizing spring 70 is hardly changed in the drive operation of the driver, and therefore, the difference in the drive force in the drive direction of the lens frame 30 (the round trip difference) can be reduced.

The voltage shown in fig. 22 is applied to the piezoelectric driver PA. When the applied voltage is changed sharply, the driving shaft S is displaced with a large acceleration, so that the friction torsion spring 60 is easily slid, and when the applied voltage is changed slowly, the driving shaft S is displaced with a small acceleration, so that the friction torsion spring 60 is not easily slid due to the slow extension (contraction) of the piezoelectric element P.

By using a round trip difference in displacement acceleration of the drive shaft S due to the applied voltage waveform, the movable body 502 movable integrally with the friction torsion spring 60 IS moved in a predetermined direction, and the lens frame 30 linked with the movable body 502 IS moved so that the distance of the lens group L with respect to the photosensitive chip IS can be changed.

An embodiment of a lens driving device in which the electromechanical transducer is arranged such that the expansion and contraction direction thereof is parallel to the optical axis of the lens will be described below with reference to fig. 24.

As shown in fig. 24, the inner diameter of the Z-axis coil spring 32 and the outer diameter of the drive shaft of the Z-axis SIDM 431 are engaged with each other to generate friction force therebetween and are fixed by friction. The Z-axis coil spring 32 is fixed in the axial direction and the circumferential direction by the Z-axis coil spring arm a 32a being restricted by the circumferential fitting surface a 304 and the axial fitting surface a 302 of the fitting portion 33, and the Z-axis coil spring arm b 32b being restricted by the circumferential fitting surface b 305 and the axial fitting surface b 303 of the fitting portion 33. When a pulse voltage of an appropriate frequency is applied to the Z-axis SIDM 431, the Z-axis coil spring 32 moves in a predetermined direction by friction with the drive shaft of the Z-axis SIDM 431. And the Z-axis coil spring 32 is limited by the axial and circumferential directions of the drive shaft of the fitting portion 33, so that the arm portion in the advancing direction of the Z-axis coil spring 32 drives the fitting portion 33, that is, drives the lens carrier 3 of the driven body to move together in the Z-axis (i.e., optical axis direction), that is, AF focus drive.

Compared with the friction structure used in the background technology and generating friction force, the scheme adopts the spiral spring inner diameter and the jogging of the spiral spring inner diameter as the moving parts on the outer diameter of the piezoelectric driving shaft, thereby reducing the size of the friction structure. Even if the drive shaft arrangement parallel to the optical axis is adopted as in the background art, there is a technical advantage of space miniaturization in the drive shaft direction as compared with the background art. Compared with the prior art, the friction contact of the coil spring in the circumference of the driving shaft is only realized by a few points, so that the friction force is more stable, the loss of the positions of the few points due to the concentration of the friction force is reduced, and the reliability is improved.

The advantages are summarized as follows:

1. by forming the moving member with a coil spring, the space of the friction structure portion can be reduced.

2. Since the contact with the periphery of the drive shaft body of the moving member is spiral, the pressure is relatively dispersed, and the contact portion is less likely to wear.

Unless specifically stated otherwise, the appearances of the phrase "first," "second," or the like herein are not meant to be limiting as to time sequence, number, or importance, but are merely for distinguishing one technical feature from another in the present specification. Likewise, the appearances of the phrase "a" or "an" in this document are not meant to be limiting, but rather describing features that have not been apparent from the foregoing. Likewise, modifiers similar to "about" and "approximately" appearing before a number in this document generally include the number, and their specific meaning should be understood in conjunction with the context. Likewise, unless a particular quantity of a noun is to be construed as encompassing both the singular and the plural, both the singular and the plural may be included in this disclosure.

The preferred embodiments of the present utility model have been described in the specification, and the above embodiments are merely for illustrating the technical solution of the present utility model and not for limiting the present utility model. All technical solutions that can be obtained by logic analysis, reasoning or limited experiments according to the inventive concept by those skilled in the art shall be within the scope of the present utility model.

Claims

1. A lens driving device comprising an electromechanical conversion element, characterized by comprising a friction portion for transmitting movement of the electromechanical conversion element, the friction portion comprising a friction spring, a moving body, a friction drive shaft; the friction spring is fixed with the moving body integrally or is used as the moving body, and the friction spring is combined with the friction driving shaft through friction.

2. The lens driving apparatus according to claim 1, wherein a friction driving shaft is coupled to one end of the electromechanical transducer element, and a weight is coupled to the other end of the electromechanical transducer element.

3. The lens driving apparatus according to claim 1, wherein the friction spring is a helical torsion friction spring; the spiral torsion friction spring is covered by a moving body which is embedded in the friction driving shaft, and arm parts at two ends of the spiral torsion friction spring are elastically contacted with inclined surfaces of the moving body.

4. The lens driving apparatus according to claim 1, comprising a conversion structure that converts a movement in a telescopic direction of the electromechanical conversion element into a movement in an optical axis direction of the lens: comprises a friction part for transmitting the movement of the electromechanical conversion element, and a cam part for converting the movement direction of the friction part into the movement of the lens in the optical axis direction.

5. The lens driving apparatus according to claim 4, wherein the cam portion includes: cam follower and corresponding driving portion, or cam driving portion and corresponding follower; wherein a slope moving in synchronization with a moving body or with a lens frame is used as the cam driving portion or the cam driven portion.

6. The lens driving apparatus according to claim 5, wherein the cam follower portion and the driving portion are pressed against each other by a power storage of an energizing spring.

7. The lens driving apparatus according to claim 5, wherein the follower portion and the cam driving portion are urged against each other by a power storage of an energizing spring.

8. A lens driving apparatus according to claim 3, wherein the friction spring is a helical torsion friction spring; the spiral torsion friction spring is covered by a moving body which is embedded in the friction driving shaft, and arm parts at two ends of the spiral torsion friction spring are elastically contacted with inclined surfaces of the moving body.

9. The lens driving device according to claim 5, wherein the cam driving portion has a slope forming an angle with respect to a direction in which the electromechanical conversion element expands and contracts or a direction in which the lens optical axis is formed, and the lens or the lens frame is driven by the cam slope acting on the driven portion integrally formed with the lens or the frame body thereof.

10. The lens driving apparatus according to claim 9, wherein the driven portion and the cam driving portion form an interaction force by an urging force of an urging spring, a straight arm of the urging spring being substantially parallel to the inclined surface.

11. The lens driving apparatus according to claim 10, wherein the energizing spring is a torsion spring of a wound coil spring type.

12. The lens driving apparatus according to claim 5, wherein the movement in the expansion and contraction direction of the electromechanical conversion element is converted into the movement in the optical axis direction of the lens, and the movable body having the driving portion is coupled to the friction driving shaft by friction.

13. The lens driving device according to claim 12, wherein the conversion structure has a cam follower portion which is a cam-acting inclined surface portion integrally formed with a lens frame and forming an angle with respect to a direction of expansion and contraction of the electric conversion element or a direction of an optical axis of the lens, and the driving portion and the cam follower portion on the movable body are brought into contact with each other, and the cam follower portion is pressed by the driving portion to drive the lens.

14. The lens driving apparatus according to claim 13, wherein the cam follower portion and the driving portion are urged by energizing with each other by an energizing spring, and an energizing portion of the energizing spring is substantially parallel to an inclined surface of the cam follower portion.

15. The lens driving apparatus according to claim 1, wherein the electromechanical conversion element is a laminated piezoelectric element.