KR101051074B1 - Compact camera driving device using piezoelectric element - Google Patents

Abstract

The present invention relates to a small camera driving apparatus using a piezoelectric element, and more particularly, to a small camera driving apparatus using a piezoelectric element to transfer the lens by driving the lens holder in the vertical direction using the piezoelectric element.

A compact camera driving apparatus using the piezoelectric element of the present invention, the base member; A lens holder disposed inside the base member and mounted with a lens and driven in an optical axis direction; A drive body for driving the lens holder in the optical axis direction; And a control unit for controlling the driving body, wherein the driving body comprises: a resonator part having one end slidably contacted with the base member and the other end contacting an outer circumferential surface of the lens holder; A first piezoelectric element and a second piezoelectric element coupled to the resonator to move the resonator; One is coupled to one surface of the first piezoelectric element between the first piezoelectric element and the resonator, and the other is coupled to the first (+) electrode and the first (GND) electrode coupled to the other surface of the first piezoelectric element. ; One is coupled to one surface of the second piezoelectric element between the second piezoelectric element and the resonator, and the other is coupled to the other surface of the second piezoelectric element and the second (GND) electrode. The controller is configured to apply an alternating voltage having a phase difference between the first (+) electrode and the second (+) electrode and having a frequency corresponding to the resonance frequency of the driving body. And reciprocating longitudinally by alternating voltages of the first resonant frequency applied to the first piezoelectric element and the second piezoelectric element, and alternating voltages of the second resonant frequency applied to the first piezoelectric element and the second piezoelectric element. Reciprocally bent in a vertical direction in the longitudinal direction by the control unit, the control unit applies an alternating voltage having an appropriate frequency between the first resonant frequency and the second resonant frequency to the first piezoelectric element and the second piezoelectric element. Thus, the other end of the resonator It is characterized in that to drive the lens holder in the optical axis direction while performing an elliptical trajectory motion.

Piezoelectric element, camera, lens holder, resonator, frequency, elliptic motion

Description

Camera Actuator using the piezoelectric element}

The present invention relates to a small camera driving apparatus using a piezoelectric element, and more particularly, to a small camera driving apparatus using a piezoelectric element to transfer the lens by driving the lens holder in the vertical direction using the piezoelectric element.

A small communication device such as a mobile phone is equipped with a small camera device.

1 is a cross-sectional structural view of a conventional small camera device of the VCM method, Figure 2 is a cross-sectional structural view of the use state of the small camera device shown in FIG.

1 and 2, the small camera apparatus shown in FIGS. 1 and 2 includes a lens group 500 including a plurality of lenses for changing the magnification of a subject or adjusting a focus of a subject, and driving the lens group 500 in an optical axis direction. Supported by the lens holder 550, the fixing part 600, and the fixing part 600 to raise the lens holder 550 to be movable in the optical axis direction, and the lens holder 550 is driven exactly in the optical axis direction. A leaf spring 650 for guiding the guide, an actuator supported by the lens holder 550 to drive the fixing unit 600 in the optical axis direction, and an image for capturing an image of a subject passing through the lens group 500. The sensor 800 and the control unit for controlling the actuator and the image sensor 800.

The leaf spring 650 has a shape in which the width of the leaf spring 650 is narrowed between the portion fixed to the fixing part 600 and the portion fixed to the lens holder 550 to facilitate deformation in the optical axis direction.

Therefore, the leaf spring 650 elastically supports the lens holder 550 to flow in the optical axis direction.

In addition, the leaf spring 650 is fixed to at least four locations of the lens holder 550, and serves as a guide for preventing the lens holder 560 from flowing in a direction orthogonal to the optical axis direction.

On the other hand, the actuator, the magnet 710 is fixed to the fixing part 600, and the lens holder 550 is fixed to the lens holder 550 receives the magnetic flux from the magnet 710 when the power is supplied from the control unit in the optical axis direction It consists of a coil 720 for generating a driving force.

The structure of such an actuator is called a VCM method.

One pair of magnets 710 and one coil 720 are provided at symmetrical portions.

The actuator also has a yoke 730 for circulating the magnetic flux of the magnet 710 efficiently.

In the small camera device having such a configuration, as shown in FIG. 2, when electricity is applied to the coil 720 of the actuator from the controller, the coil 720 moves in the optical axis direction under the influence of the magnetic flux from the magnet 710. To generate an electromagnetic force.

Therefore, the fixing part 600 to which the coil 720 is fixed moves in the optical axis direction.

In this way, the controller raises or lowers the lens group 500 in the optical axis direction so that the image captured by the image sensor 800 becomes clear.

The above-mentioned VCM method works well when the size of the lens holder is small or light in weight, but when the size of the lens holder is large or heavy, there is a problem in that the operation force is not good due to weak moving force.

In addition, the VCM method is not robust, so when a drop test is performed a lot of defective products, the moving distance of the lens holder is short, there is a problem that is difficult to use in the case of a camera using a high pixel sensor.

The present invention provides a compact camera driving apparatus using a piezoelectric element that can be used for a camera equipped with a high pixel sensor because the lens holder works well, is more robust than the VCM method, and has a longer moving distance of the lens holder. There is this.

Small camera driving apparatus using the piezoelectric element of the present invention to achieve the above object, the base member; A lens holder disposed inside the base member and mounted with a lens and driven in an optical axis direction; A drive body for driving the lens holder in the optical axis direction; And a control unit for controlling the driving body, wherein the driving body comprises: a resonator part having one end slidably contacted with the base member and the other end contacting an outer circumferential surface of the lens holder; A first piezoelectric element and a second piezoelectric element coupled to the resonator to move the resonator; One is coupled to one surface of the first piezoelectric element between the first piezoelectric element and the resonator, and the other is coupled to the first (+) electrode and the first (GND) electrode coupled to the other surface of the first piezoelectric element. ; One is coupled to one surface of the second piezoelectric element between the second piezoelectric element and the resonator, and the other is coupled to the other surface of the second piezoelectric element and the second (GND) electrode. The controller is configured to apply an alternating voltage having a phase difference between the first (+) electrode and the second (+) electrode and having a frequency corresponding to the resonance frequency of the driving body. And reciprocating in the longitudinal direction by the alternating voltage of the first resonant frequency applied to the first piezoelectric element and the second piezoelectric element, and the alternating voltage of the second resonant frequency applied to the first piezoelectric element and the second piezoelectric element. Reciprocally bent in a vertical direction in the longitudinal direction by the control unit, by applying an alternating voltage having an appropriate frequency between the first resonant frequency and the second resonant frequency to the first piezoelectric element and the second piezoelectric element , The other end of the resonator unit It is characterized in that to drive the lens holder in the optical axis direction while performing an elliptical trajectory motion.

The resonator unit includes: a first piezoelectric element coupling unit on which the first piezoelectric element is mounted; A second piezoelectric element coupling part on which the second piezoelectric element is mounted; One end is connected to the first piezoelectric element coupling portion, the other end is connected to the second piezoelectric element coupling portion, and a central portion is formed of a movable part that performs an elliptical displacement movement by the first piezoelectric element and the second piezoelectric element. The central portion of the movable part protrudes in a direction opposite to the first piezoelectric element and the second piezoelectric element, and is provided with a friction member, and the lens holder is equipped with a friction part in contact with the friction member.

When the alternating voltage is applied, the first piezoelectric element coupling part and the second piezoelectric element coupling part are stretched by the first piezoelectric element and the second piezoelectric element with a phase difference in the longitudinal direction of the resonator part, and the movable part of the resonator part is elliptical displacement. Try to exercise.

It further comprises an elastic means for adding an elastic force so that the friction member moves in the direction in contact with the frictional portion during expansion and contraction of the resonator.

The base member is formed with a side portion parallel to the moving direction of the lens holder, and the cover member is mounted on the side portion of the base member is covered, the sliding portion is formed in the side portion of the base member is the driving body is seated The actuator is disposed in the sliding groove, and the other end of the resonator is extended in the longitudinal direction, and the driver is disposed between the side portion of the base member and the cover member.

And a pressing member which contacts the one end of the resonator and pushes the resonator in the direction of the frictional part. The friction member mounted on the other end of the resonator unit is in close contact with the frictional part.

And a circuit board for supplying power to the first piezoelectric element and the second piezoelectric element, wherein the first (GND) electrode is coupled to one surface of the first piezoelectric element between the first piezoelectric element and the resonance part. The first (+) electrode is coupled to the other surface of the first piezoelectric element, and the second (GND) electrode is coupled to one surface of the second piezoelectric element between the second piezoelectric element and the resonator. A 2 (+) electrode is coupled to the other surface of the second piezoelectric element, and the circuit board includes: both terminal portions connected to the first (+) electrode and the second (+) electrode; And a negative terminal portion connected to the first (GND) electrode and the second (GND) electrode, wherein the negative terminal portion is disposed between one end of the resonator and the pressing member to be connected to the first (GND) electrode. It is connected to the electrode and the second (GND) electrode.

The first piezoelectric element coupling portion and the second piezoelectric element coupling portion are disposed in parallel to each other.

The first resonant frequency is a frequency such that the stretching motion of the first piezoelectric element coupling part and the second piezoelectric element coupling part is the same, and the second resonant frequency is the first piezoelectric element coupling part and the second piezoelectric element coupling. This is the frequency that the negative stretching movements take place alternately.

The base member has a side portion parallel to the moving direction of the lens holder, and a movement guide member for smoothly moving the lens holder is disposed between the side portion of the base member and the lens holder, the movement The guide member includes a retainer disposed between the side portion and the lens holder; The ball member is rotatably inserted into the retainer and is in contact with the side portion and the lens holder.

One of the inner circumferential surface of the base member or the outer circumferential surface of the lens holder is formed with a guide protrusion in the moving direction of the lens holder, the other is formed with a guide groove into which the guide protrusion is inserted, the left and right flow of the lens holder To prevent.

According to the small camera driving apparatus using the piezoelectric element of the present invention as described above, even if the weight of the lens holder is heavy, it works well, is more robust than the VCM method, and the moving distance of the lens holder is long in the camera equipped with a high pixel sensor Can be used.

In addition, since the present invention uses two piezoelectric elements, a stronger elliptic motion may be generated in the movable part, so that the movement of the lens holder can be made more quickly.

Figure 3 is a perspective view of a small camera driving apparatus according to an embodiment of the present invention, Figure 4 is an exploded perspective view of the cover member is separated in the compact camera driving apparatus according to an embodiment of the present invention, Figure 5 is 6 is a plan view in a state of FIG. 4, FIG. 7 is an exploded perspective view of a cover member and a lens holder separated in the compact camera driving apparatus according to the embodiment of the present invention, and FIG. Figure 7 is a perspective view of the base member and the driving body, Figure 9 is an exploded perspective view exploded in part of the configuration in Figure 8, Figure 10 is an exploded perspective view exploded in the entire configuration in Figure 8, Figure 11 is an embodiment of the present invention FIG. 12 is a state diagram showing a state of motion according to the first resonant frequency of the drive body according to the present invention, FIG. 12 is a state diagram showing a state of motion according to the second resonant frequency of the drive body according to the embodiment of the present invention, and FIG. According to an embodiment of the invention It is a state diagram which shows the elliptic motion state of a movable part according to the appropriate frequency of a drive body.

As shown in FIGS. 3 to 10, the compact camera driving apparatus using the piezoelectric element of the present invention includes a base member 10, a lens holder 20, a cover member 30, and a driving body 40. , The elastic means 60, the pressing member 65, the circuit board 70, the control unit and the like.

The lens holder 20 is disposed inside the base member 10, and an image sensor (not shown) is disposed below.

The base member 10 is formed with a side portion 11 parallel to the moving direction of the lens holder 20.

The lens holder 20 includes a lens (not shown) therein and is driven by moving in the optical axis direction, that is, the vertical direction.

On the outer circumferential surface of the lens holder 20, a friction part 21 for contacting the drive body 40 is formed long in the vertical direction.

In addition, the movement guide member 15 is disposed between the side portion 11 of the base member 10 and the lens holder 20 so as to smoothly move the lens holder 20 up and down. .

The movement guide member 15 includes a retainer 16 disposed between the side portion 11 and the lens holder 20 and a ball member 17 rotatably inserted into the retainer 16.

The retainer 16 is not in contact with the side portion 11 and the lens holder 20, and the ball member 17 is in contact with the side portion 11 and the lens holder 20.

To this end, the diameter of the ball member 17 is larger than the thickness of the retainer 16.

In addition, the side grooves 11 and the lens holder 20 are formed with rail grooves 13 and 23 extending in the vertical direction to allow the ball member 17 to move.

When the lens holder 20 moves, the retainer 16 moves only about half of the moving distance of the lens holder 20.

And, either one of the base member 10 or the lens holder 20 is formed with a guide protrusion 24 in the moving direction of the lens holder 20, the other is the guide protrusion 24 is inserted A guide groove 14 is formed to prevent the lens holder 20 from flowing by rotating in the left and right directions.

In the present embodiment, the guide protrusions 24 are formed on the outer circumferential surface of the lens holder 20 in the vertical direction, and the guide grooves 14 are formed in the base member 10 in the vertical direction.

The cover member 30 is mounted to the base member 10 to cover the side portion 11 and the upper portion of the base member 10.

The driving body 40 drives the lens holder 20 by pushing or pulling in the optical axis direction, that is, the vertical direction.

The driving body 40 includes a resonator 41, a first piezoelectric element 46, and a second piezoelectric element 47.

The resonator 41 is formed of phosphor bronze, one end of which is slidably disposed in contact with the base member 10, and the other end of the resonator 41 contacts the to-be-triggered part 21 in detail. have.

The resonator 41 includes a first piezoelectric element coupling part 42, a second piezoelectric element coupling part 43, a movable part 44, and a friction member 45.

The first piezoelectric element coupling portion 42 and the second piezoelectric element coupling portion 43 each have a flat plate shape, one surface of which is in contact with the base member 10, and the other of the first piezoelectric element 46 is formed on the other surface thereof. And a second piezoelectric element 47 is mounted.

The first piezoelectric element coupling portion 42 and the second piezoelectric element coupling portion 43 are disposed in parallel to each other.

One end of the movable portion 44 is connected to the first piezoelectric element coupling portion 42, and the other end thereof is connected to the second piezoelectric element coupling portion 43. It protrudes in the opposite direction of the second piezoelectric element 47.

In addition, the friction member 45 in contact with the frictional portion 21 is mounted on the protruding central portion of the movable portion 44.

The friction member 45 mounted on the central portion of the movable part 44 performs an elliptical displacement movement by the first piezoelectric element 46 and the second piezoelectric element 47.

The friction member 45 is coupled to a protruding center portion of the movable part 44, and contacts the to-be-friction part 21 mounted to the lens holder 20 during the movement of the movable part 44. 20) to transmit the force to move up and down.

The first piezoelectric element 46 and the second piezoelectric element 47 are mounted on the resonator 41 in detail, the first piezoelectric element coupling part 42 and the second piezoelectric element coupling part 43, respectively. The current is supplied from the circuit board 70 to be deformed to serve to operate the resonator 41.

A first (+) electrode is coupled to one surface of the first piezoelectric element 46 between the first piezoelectric element 46 and the resonator unit 41, and a first surface of the first piezoelectric element 46 is coupled to the first surface. (GND) electrodes are coupled.

In addition, a second (+) electrode is coupled to one surface of the second piezoelectric element 47 between the second piezoelectric element 47 and the resonator 41, and the other surface of the second piezoelectric element 47. It is coupled to the second (GND) electrode.

The first (+) electrode, the first (GND) electrode, the second (+) electrode, and the second (GND) electrode are formed on one surface and the other surface of the first piezoelectric element 46 and the second piezoelectric element 47. Since they are thinly attached, they are not separately shown in the drawings.

Unlike the present embodiment, the first (GND) electrode and the second (GND) electrode are coupled to one surface of the first piezoelectric element 46 and one surface of the second piezoelectric element 47, respectively, and the first piezoelectric element The first (+) electrode and the second (+) electrode may be coupled to the other surface of the 46 and the other surface of the second piezoelectric element 47, respectively.

The first (+) electrode, the first (GND) electrode, the second (+) electrode, and the second (GND) electrode are mounted in parallel with each other along the longitudinal direction of the resonator 41.

The first piezoelectric element 46 and the second piezoelectric element 47 are applied with an alternating voltage (AC) having an appropriate frequency having a phase difference between the first (+) electrode and the second (+) electrode. The first piezoelectric element 46 and the second piezoelectric element 47 are stretched in the longitudinal direction of the resonator 41 to drive the resonator 41.

When the first piezoelectric element 46 and the second piezoelectric element 47 expand and contract, the first piezoelectric element coupling portion 42 and the second piezoelectric element coupling portion 43 together of the resonator 41 Stretched in the longitudinal direction, the movable portion 44 of the resonator portion 41 to the elliptical displacement movement.

The alternating voltages applied to the first (+) electrode and the second (+) electrode may preferably have a phase difference of 90 degrees.

The elastic means 60 and / or the pressing member 65 is one end of the resonator 41, one end of the first piezoelectric element coupling part 42 and one end of the second piezoelectric element coupling part 43. Is pushed toward the frictional portion 21 so that the friction member 45 mounted at the other end of the resonator portion 41 is in contact with the frictional portion 21.

To this end, the pressing member 65 is composed of a '66' shaped support portion 66, and the pressing portion 67 formed on both sides of the support portion 66.

The pressing part 67 is connected to one end of the resonator part 41, that is, one end of the first piezoelectric element coupling part 42 and one end of the second piezoelectric element coupling part 43, respectively. Push in the other end.

In order for the pressing part 67 to push the one end of the resonator part better in the other end direction, the lengths of the first piezoelectric element coupling part 42 and the second piezoelectric element coupling part 43 are measured. It is formed longer than the length of the first piezoelectric element 46 and the second piezoelectric element 47, one end of the first piezoelectric element coupling portion 42 and one end of the second piezoelectric element coupling portion 43, respectively In this case, one end of the first piezoelectric element coupling part 42 and one end of the second piezoelectric element coupling part 43 which are bent by the pressing part 67 may be pushed in the other end direction.

Thus, the friction member 45 mounted on the movable part 44 formed at the other end of the resonance part 41 may be in strong contact with the frictional part 21 at all times.

The support part 66 is slidably mounted to the base member 10 in the direction of the frictional part 21.

The elastic means 60 is made of a coil spring, to add an elastic force so that the pressing member 65 moves in the direction of the frictional portion (21).

In the present embodiment, the support member 18 is formed on the base member 10, and the elastic member 60 is disposed between the support protrusion 18 and the support portion 66, thereby supporting the support portion 66. An elastic force to move in the direction of the friction portion 21 was added.

When the force to move in the direction of the friction portion 21 is applied to the support portion 66 as described above, the force to move in the direction of the friction portion 21 is also applied to the pressing portion 67, naturally The pressing part 67 pushes one end of the resonator part 41 toward the frictional part 21, and thus, the movable part 44 formed at the other end of the resonance part 42 has the frictional part ( 21) The force to move in the direction becomes strong.

Therefore, when the resonator 41 expands and contracts, the resonator 41 moves in and out in a state in which the resonator 41 is slidably disposed without being separated from the base member 10. The friction member 45 coupled to the other end is driven.

An elastic force is always applied to the friction member 45 coupled to the other end of the resonator 41 by the elastic means 60 to move in the direction of the frictional part 21, and thus the friction member 45. And the frictional part 21 can be kept in contact at all times.

Unlike the present embodiment, one end of the elastic means 60 is coupled to the base member 10 and the other end is coupled to the resonator 41, the resonator by the elastic force of the elastic means 60 ( The force to move in the direction of the friction part 21 may be applied to 41.

The circuit board 70 supplies power to the first piezoelectric element 46 and the second piezoelectric element 47.

The circuit board 70 includes a positive electrode portion 71 and a negative electrode portion 72.

The positive electrode portion 71 is coupled to the other surface of the first piezoelectric element 46 and the other surface of the second piezoelectric element 47 to expose the first (+) electrode and the second (+) to the outside. Connected to the electrode.

The negative electrode portion 72 is disposed between one end of the resonator portion 41 and the pressing portion 67 of the pressing member 65 so that the first (GND) electrode is formed by the resonator portion 41. And a second (GND) electrode.

That is, the pressing unit 67 pushes one ends of the negative electrode unit 72 and the resonator unit 41 toward the frictional unit 10, respectively, so that the negative electrode unit 72 moves to the resonator unit 41. Make sure you are in close contact with

Two positive electrode portions 71 and two negative electrode portions 72 are formed.

On the other hand, the side surface 11 of the base member 10 is formed with a sliding groove 12 on which the drive body 40 is seated, and the drive body 40 is disposed in the sliding groove 12. .

As described above, by forming the sliding groove 12 in the side portion 11 of the base member 10 and by placing the drive body 40 therein, the overall size can be reduced.

The driving body 40 inserted into the sliding groove 12 is disposed between the side portion 11 of the base member 10 and the cover member 30 so as not to be separated to the outside.

Of course, the pressing member 65, the elastic means 60 and the circuit board 70 is also disposed between the side portion 11 and the cover member 30 of the base member 10.

The controller controls the driving body 40, and in detail, the driving body 40 is driven by controlling an alternating voltage applied to the first piezoelectric element 46 and the second piezoelectric element 47. It serves to move the lens holder 20 in the vertical direction.

The control unit may apply an alternating voltage having a phase difference of 90 degrees to each of the first (+) electrode and the second (+) electrode and having a frequency corresponding to an appropriate frequency of the driver 40, thereby providing the resonance unit. The movable part 44 located at the other end of the head 41 drives the lens holder 20 in the optical axis direction while performing an elliptical displacement motion.

11 to 13 illustrate the motion of the movable part 44 by the drive body 40, and show the motion state of the resonator part 41.

The other end of the resonator 41, that is, the movable part 44, is connected to the alternating voltage of the first resonant frequency applied to the first piezoelectric element 46 and the second piezoelectric element 47 as shown in FIG. 11. To reciprocate in the longitudinal direction.

12, the movable part 44 is bent in the vertical direction in the longitudinal direction by the alternating voltage of the second resonant frequency applied to the first piezoelectric element 46 and the second piezoelectric element 47, as shown in FIG. Do a vertical reciprocating movement.

At this time, the first piezoelectric element coupling part 42 and the second piezoelectric element coupling part 43 have the same stretching motion by the first resonant frequency.

That is, the first piezoelectric element coupling portion 42 and the second piezoelectric element coupling portion 43 have the same phase difference and expand and contract in the same manner.

In addition, the first piezoelectric element coupling portion 42 and the second piezoelectric element coupling portion 43 are stretched and contracted alternately by the second resonant frequency.

That is, when the first piezoelectric element coupling portion 42 is extended, while the first piezoelectric element coupling portion 42 and the second piezoelectric element coupling portion 43 have substantially opposite phase differences, Coupling portion 43 is to be contracted movement.

The controller applies an alternating voltage having an appropriate frequency between the first resonance frequency and the second resonance frequency to the first piezoelectric element 46 and the second piezoelectric element 47, as shown in FIG. 13. The movable part 44 located at the other end of the resonator 41 drives the lens holder 20 in the optical axis direction while performing an elliptical trajectory movement.

The appropriate frequency is a frequency having a value of 1/2 of the sum of the first resonant frequency and the second resonant frequency, and the range of the second resonant frequency is a first resonance frequency and a first antiresonance. It is preferable that the value is between the antiresonance frequency.

As described above, by applying an alternating voltage having a phase difference of 90 degrees and having the appropriate frequency to the first piezoelectric element 46 and the second piezoelectric element 47, the length of the movable part 44 by the first resonance frequency is applied. The directional motion (Fig. 11) and the vertical motion (Fig. 12) by the second resonant frequency are combined to make an elliptic motion (Fig. 13).

Hereinafter, an operation process of the present invention having the above-described configuration will be described.

The controller applies an alternating voltage having a phase difference of 90 degrees to the first (+) electrode and the second (+) electrode respectively connected to the first piezoelectric element 46 and the second piezoelectric element 47.

That is, the phase of the alternating voltage applied to the first (+) electrode and the second (+) electrode has a difference of 90 degrees.

At this time, the frequency of the alternating voltage applied is an appropriate frequency corresponding to the middle of the first resonant frequency and the second resonant frequency of the drive body 40.

When an alternating voltage having an appropriate frequency having a phase difference of 90 degrees is applied to the first (+) electrode and the second (+) electrode, the first piezoelectric element 46 and the second piezoelectric element 47 extend and contract, respectively. As a result, the first piezoelectric element coupling part 42 and the second piezoelectric element coupling part 43, to which the first piezoelectric element 46 and the second piezoelectric element 47 are coupled, may flow, thereby causing the resonance unit ( 41) flows.

At this time, since the frequency of the alternating voltage applied is an appropriate frequency positioned between the first resonant frequency and the second resonant frequency of the drive body 40, the resonator unit 41 in detail with little force. ) Can be greatly flown.

On the other hand, since the other end of the resonator portion 41 is pressed by the pressing member 65 and the elastic means 60 to the friction target portion 21, the other end direction of the resonator portion 41 The flow is transferred to the friction part 21.

More specifically, as shown in FIG. 11, the movable part 44 formed at the other end of the resonator 41 by the first resonant frequency is reciprocated in the longitudinal direction.

As shown in FIG. 12, the movable unit 44 reciprocates in the vertical direction by the second resonance frequency.

When the first resonant frequency for causing the movable part 44 to reciprocate in the longitudinal direction is 364 kHz, and the second resonant frequency for causing the movable part 44 to reciprocate in the up and down direction is 366 kHz, the controller controls the first resonant frequency to be 366 kHz. A proper frequency of 365 kHz, which is an average value of the sum of the first resonance frequency and the second resonance frequency, is applied to the first piezoelectric element 46 and the second piezoelectric element 47.

Then, as shown in FIG. 13, the movable part 44 is combined with the vibration mode in the longitudinal direction and the vibration mode in the vertical direction to perform an elliptic motion.

When the alternating voltage as described above is applied, as shown in FIG. 13, the friction member 45 coupled to the other end of the movable part 44 performs an elliptic motion.

On the other hand, when the difference between the first resonant frequency and the second resonant frequency is large, the difference between the proper frequency and the first resonant frequency and the second resonant frequency is turned on to apply an alternating voltage having an appropriate frequency to the movable unit 44 Even if the movable portion 44 may not be an elliptic movement.

As the movable part 44 performs an elliptical displacement movement, the friction member 45 coupled to the movable part 44 comes into contact with the frictional part 21 mounted to the lens holder 20 and the lens. The holder 20 is pushed up or pushed down to allow the lens holder 20 to move in the optical axis direction.

And, since the elastic means 60 adds an elastic force to the other end of the resonator portion 41 in the direction of the friction portion 21, the friction member 45 mounted on the movable portion 44 is It may be in close contact with the friction portion 21 mounted on the lens holder 20.

As a result, the movable part 44 is always in contact with the outer circumferential surface of the lens holder 20 to thereby strongly move the lens holder 20 in the vertical direction.

The compact camera driving apparatus using the piezoelectric element of the present invention is not limited to the above-described embodiment, and may be variously modified and implemented within the range in which the technical idea of the present invention is permitted.

1 is a cross-sectional structure diagram of a conventional small camera device of the VCM method,

2 is a cross-sectional structural view of the state of use of the small camera device shown in FIG.

3 is a perspective view of a compact camera driving apparatus according to an embodiment of the present invention;

Figure 4 is an exploded perspective view of the cover member is separated in the compact camera driving apparatus according to an embodiment of the present invention,

5 is a front view in the state of FIG. 4;

6 is a plan view in the state of FIG. 4;

7 is an exploded perspective view of a cover member and a lens holder separated from the compact camera driving apparatus according to the embodiment of the present invention;

8 is a perspective view of the base member and the driving body in FIG. 7,

9 is an exploded perspective view showing a part of the configuration shown in FIG. 8;

11 is a state diagram showing a state of motion according to the first resonant frequency of the drive body according to an embodiment of the present invention,

12 is a state diagram showing a state of motion according to the second resonant frequency of the drive body according to an embodiment of the present invention,

13 is a state diagram showing an elliptic motion state of the movable part according to the appropriate frequency of the drive body according to an embodiment of the present invention,

<Description of the symbols for the main parts of the drawings>

10: base member, 11: side part, 12: sliding groove, 13: rail groove, 14: guide groove, 15: moving guide member, 16: retainer, 17: ball member, 18: support protrusion, 20: lens holder, 21 : Friction part, 23: rail groove, 24: guide protrusion, 30: cover member, 40: driving body, 41: resonator, 42: first piezoelectric element coupling part, 43: second piezoelectric element coupling part, 44: Movable part, 45: friction member, 46: first piezoelectric element, 47: second piezoelectric element, 60: elastic means, 65: pressing member, 66: supporting portion, 67: pressing portion, 70: circuit board, 71: positive electrode portion, 72: negative electrode portion,

Claims (11)

A base member; A lens holder disposed inside the base member and mounted with a lens and driven in an optical axis direction; A drive body for driving the lens holder in the optical axis direction; It consists of a control unit for controlling the drive body, The drive body, A resonator part of which one end is slidably disposed in contact with the base member and the other end of which is in contact with an outer circumferential surface of the lens holder; A first piezoelectric element and a second piezoelectric element coupled to the resonator to move the resonator; One is coupled to one surface of the first piezoelectric element between the first piezoelectric element and the resonator, and the other is coupled to the first (+) electrode and the first (GND) electrode coupled to the other surface of the first piezoelectric element. ; One is coupled to one surface of the second piezoelectric element between the second piezoelectric element and the resonator, and the other is coupled to the other surface of the second piezoelectric element and the second (GND) electrode. It consists of The control unit, An alternating voltage having a phase difference between the first (+) electrode and the second (+) electrode and having a frequency corresponding to the resonance frequency of the driving body is applied, The other end of the resonator unit, Reciprocating in the longitudinal direction by the alternating voltage of the first resonant frequency applied to the first piezoelectric element and the second piezoelectric element, and to the alternating voltage of the second resonant frequency applied to the first piezoelectric element and the second piezoelectric element By reciprocating bent in the vertical direction in the longitudinal direction, The control unit applies an alternating voltage having an appropriate frequency between the first resonance frequency and the second resonance frequency to the first piezoelectric element and the second piezoelectric element, so that the other end of the resonator has an elliptic locus motion. A small camera driving apparatus using a piezoelectric element, characterized in that for driving the lens holder in the optical axis direction. The method of claim 1, The resonator unit, A first piezoelectric element coupling part on which the first piezoelectric element is mounted; A second piezoelectric element coupling part on which the second piezoelectric element is mounted; One end is connected to the first piezoelectric element coupling portion, the other end is connected to the second piezoelectric element coupling portion, and a central portion is formed of a movable part that performs an elliptical displacement movement by the first piezoelectric element and the second piezoelectric element. Lose, On the center of the movable portion is formed protruding in the opposite direction of the first piezoelectric element and the second piezoelectric element and is equipped with a friction member, The lens holder is a compact camera driving device using a piezoelectric element, characterized in that the friction portion in contact with the friction member is mounted. 3. The method of claim 2, When the alternating voltage is applied, the first piezoelectric element coupling portion and the second piezoelectric element coupling portion are stretched by the first piezoelectric element and the second piezoelectric element with a phase difference in the longitudinal direction of the resonance portion, and the movable portion of the resonance portion is elliptical. Small camera driving apparatus using a piezoelectric element, characterized in that for displacement movement. The method of claim 3, And a resilient means for adding an elastic force so that the friction member moves in a direction in contact with the frictional part when the resonator is expanded and contracted. The method of claim 1, The base member has a side portion parallel to the moving direction of the lens holder, The side of the base member is covered with a cover member is mounted, The side surface of the base member is formed with a sliding groove on which the drive body is seated, The driving body is disposed in the sliding groove, the other end of the resonator is stretched in the longitudinal direction, The driving device is a compact camera driving device using a piezoelectric element, characterized in that disposed between the side of the base member and the cover member. The method of claim 4, wherein Further comprising a pressing member in contact with one end of the resonator unit to push the resonator unit toward the frictional unit, The elastic means applies an elastic force to the pressing member so that the pressing member pushes one end of the resonator in the other end, so that the friction member mounted on the other end of the resonator is in close contact with the frictional part. Compact camera driving device using the device. The method of claim 6, It further comprises a circuit board for supplying power to the first piezoelectric element and the second piezoelectric element, The first (GND) electrode is coupled to one surface of the first piezoelectric element between the first piezoelectric element and the resonator, the first (+) electrode is coupled to the other surface of the first piezoelectric element, and the second ( GND) electrode is coupled to one surface of the second piezoelectric element between the second piezoelectric element and the resonator, the second (+) electrode is coupled to the other surface of the second piezoelectric element, The circuit board, Both terminal portions connected to the first (+) electrode and the second (+) electrode; It comprises a negative terminal connected to the first (GND) electrode and the second (GND) electrode, The negative terminal unit is disposed between one end of the resonator and the pressing member is connected to the first (GND) electrode and the second (GND) electrode by the resonator unit, characterized in that the compact camera drive device using a piezoelectric element. The method according to any one of claims 2 to 4, 6 and 7, And the first piezoelectric element coupling portion and the second piezoelectric element coupling portion are arranged in parallel with each other. The method according to any one of claims 2 to 4, 6 and 7, The first resonant frequency is a frequency such that the expansion and contraction movement of the first piezoelectric element coupling portion and the second piezoelectric element coupling portion are equal. The second resonant frequency is a small camera driving device using a piezoelectric element, characterized in that the frequency to perform the stretching movement of the first piezoelectric element coupling portion and the second piezoelectric element coupling portion alternately. The method according to any one of claims 1 to 7, The base member has a side portion parallel to the moving direction of the lens holder, Between the side of the base member and the lens holder, the movement guide member for smoothly moving the lens holder is disposed, The movement guide member, A retainer disposed between the side portion and the lens holder; And a ball member rotatably inserted into the retainer, the ball member being in contact with the side portion and the lens holder. The method according to any one of claims 1 to 7, One of the inner circumferential surface of the base member or the outer circumferential surface of the lens holder is formed with a guide protrusion in the moving direction of the lens holder, the other is formed with a guide groove into which the guide protrusion is inserted, the left and right flow of the lens holder Small camera driving apparatus using a piezoelectric element, characterized in that for preventing.

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