JP2008164870A - Drive mechanism using piezoelectric element, camera module using the drive mechanism, and portable terminal equipped with the camera module - Google Patents

Abstract

A piezoelectric element is used to prevent the camera module from being reduced in size even if it is incorporated in a camera module, and the frictional force that hinders the operation of a moving body can be minimized to effectively use the driving force of the piezoelectric element. It is an object to provide a small driving mechanism, a camera module and a portable terminal using the driving mechanism.
Piezoelectric elements extending in a plate shape are stacked in the thickness direction, and driving heads 310 and 320 are provided at substantially the center in the longitudinal direction. A movable body pressing spring 34 is provided which sandwiches the movable body 33 extending in the longitudinal direction of the element and urges the movable body in a point-contact manner from a direction perpendicular to the moving direction of the movable body. A compact driving mechanism that can effectively use the driving force by the piezoelectric element, a camera module and a mobile terminal using the driving mechanism, and a frictional force that is reduced without a holding mechanism.
[Selection] Figure 2

Description

The present invention relates to a drive mechanism using a piezoelectric element, a camera module used in a mobile terminal such as a mobile phone using the drive mechanism, and a mobile terminal equipped with the camera module.
A drive mechanism configured in a small size using a piezoelectric element such as a piezo element (PZT), a camera module configured to be moved in the optical axis direction using the drive mechanism, and a camera module configured in a small size, and the camera module It relates to mobile terminals.

  The camera modules used in portable terminals such as mobile phones are the same as those of ordinary electronic cameras (digital cameras) as the number of pixels of image sensors such as CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) increases. In addition, high-speed, high-precision autofocus (AF) function and focal length change (zoom) function are required, and the miniaturization and weight reduction of the mobile terminal itself inevitably leads to miniaturization and weight reduction of the camera module. It is desired.

  In a camera module equipped with an autofocus and focal length change (zoom) mechanism, it is necessary to move the lens group in the optical axis direction. For this reason, conventionally, a cylindrical cam or lead screw is driven by a motor, Autofocus and zooming have been realized by moving the focusing lens group and the zoom lens group. However, when a motor is used, an electromagnet or permanent magnet is required around the rotor, and even if the axial length is shortened, the cylindrical part is indispensable. In addition, noise is also generated.

  Therefore, various camera modules that realize such autofocus and zooming using a piezoelectric element such as a piezo element (PZT) as a drive source have been proposed, and the applicant of the present application is also disclosed in Patent Document 1, Patent Document 2, etc. A camera module using a friction drive type drive source using a piezoelectric ceramic (piezo element) has been proposed.

  A friction drive type drive source using a piezoelectric ceramic (piezo element) used in Patent Document 1, Patent Document 2, etc. is, for example, as shown in Patent Document 3, a substantially rectangular plate-shaped piezoelectric ceramic. In the (piezo element), the opposite sides of the first surface formed in the longitudinal direction and the transverse direction are connected to each other and divided into 4 blocks. An electrode is provided for each block and the electrodes arranged in the diagonal direction are wires. In addition, one electrode is provided on the entire second surface opposite to the first surface.

  On the third surface in the short direction, a spacer, which is a relatively hard ceramic operating portion, is attached, for example, in the vicinity of the approximate center of the side by a bonding agent, and engages with a relatively moving object. ing. Further, the piezoelectric ceramic (piezo element) is supported by a pair of support bodies fixed around and a support body with a spring so as to be deformable, and applies a positive voltage to the pair of electrodes arranged in the longitudinal direction on the first surface. When applying a negative voltage to a pair of adjacent electrodes, the side on which the positive voltage is applied is longer than the side on which the negative voltage is applied, and it can be deformed by being supported by a support with a spring. It moves to the side where the negative voltage of the object with which the spacer is engaged is applied.

  When the voltage is no longer applied, the piezoelectric ceramic (piezo element) returns to its original state. At this time, for example, when an asymmetric voltage pulse whose fall time is at least four times longer than the rise time is applied to the electrode, the piezoelectric ceramic. Due to the friction between the spacer and the object in the (piezo element), the spacer returns to the initial position while the spacer and the object are engaged at the fall of the pulse. By repeating this and repeating this, the spacer and the object move in the opposite directions.

  The camera module shown in Patent Document 1 and Patent Document 2 proposed by the applicant of the present application uses a piezoelectric element such as a piezo element (PZT) configured in this way as a drive source. For example, the camera shown in Patent Document 1 In the module, the rotor is attached to a lead screw that is engaged with the lens holder and is provided parallel to the optical axis, and the side surface of the rotor is driven by a piezo element spacer that is also provided parallel to the optical axis. The lens holder can be driven in the optical axis direction.

  Further, in the camera module disclosed in Patent Document 2, the lens holding portion is held so as to be movable in the optical axis direction by a plurality of guide shafts arranged substantially symmetrically and in parallel with respect to the optical axis. The longitudinal direction of the piezo element is attached to the lens holding part at a right angle to the optical axis direction so that the operating part comes into contact with the optical element, and the lens holding part is moved relative to the shaft member by driving the piezo element, so that the optical axis It can be driven in the direction.

  In addition, the friction drive type drive source using the piezoelectric ceramic (piezo element) is not limited to the one shown in Patent Document 3 described above. For example, Patent Document 4 includes two piezoelectric elements. Piezoelectric elements that are arranged so as to be orthogonal to each other and that drive the tip member that contacts the cylindrical surface of the rotatable rotor provided at the intersection of the piezoelectric elements to draw an elliptical locus, thereby rotating the rotor An actuator is shown.

  Further, in Patent Documents 5 and 6, a plate-shaped member such as a piezoelectric material, an electrostrictive material, an antiferroelectric material, or the like that changes its shape when applied with current or voltage is used. The drive member is composed of a connected bent portion and a drive pad provided at the central portion, and a rail that extends parallel to the longitudinal direction of the drive member body and is pressed against the drive pad. A near-resonant electromechanical motor is shown in which the applied traveling wave energy causes the drive pad to move relative to the rail as the drive pad moves in an elliptical shape.

JP 2006-98575 A JP 2006-98600 A Japanese Patent No. 2980541 JP 2000-139086 A JP 2005-530475 A Pub, no. ; US 2005/0134146

  However, the camera module disclosed in Patent Document 1 includes a lead screw provided parallel to the optical axis and a rotor attached to the lead screw and driven by a spacer of a piezo element. The width or depth of the camera module increases. Further, the camera module disclosed in Patent Document 2 also includes a shaft member that is substantially symmetrical and arranged in parallel with the lens holding portion around the optical axis, and a piezoelectric element in which the operating portion abuts on the shaft member. Existence increases the width or depth of the camera module and prevents further miniaturization. Further, Patent Document 3, Patent Document 4, Patent Document 5, and Patent Document 6 each show only a driving member using a piezoelectric element, and the driving member holds the moving body in some form. A mechanism is required, and the frictional force is so large that if the driving force by the piezo element is not increased, the force to move the driven body is weak and efficient driving cannot be performed. In addition, these documents do not show the configuration used for the camera module.

  Therefore, in the present invention, a piezoelectric element such as a piezo element (PZT) is used so as not to prevent downsizing of the camera module even if it is incorporated in the camera module, and the frictional force that hinders the operation of the moving body is reduced as much as possible. A small drive mechanism that can effectively use the driving force of the element, a camera module that is configured to be small and light by moving the lens in the optical axis direction using the drive mechanism, and the camera module It is a problem to provide a portable terminal.

In order to solve the above problems, the drive mechanism using the piezoelectric element according to the present invention is:
A driving member formed by laminating piezoelectric elements extending in a plate shape in the thickness direction;
A drive head provided at the approximate center in the longitudinal direction of the surface layer of the drive member;
A moving body that contacts the driving head and moves by receiving a driving force;
A moving body pressing spring that urges the moving body in a point-contact manner from a direction perpendicular to the moving direction of the moving body,
The movable body is sandwiched between the drive heads of the pair of drive members and extends in the longitudinal direction of the drive members,
The moving body pressing spring urges the moving body in a direction of pressing either of the pair of drive heads,
The moving member is moved in the longitudinal direction by the driving head that performs a pseudo circular motion with the longitudinal direction of the moving member as a tangent by the driving member.

In addition, the camera module incorporating this drive mechanism
At least one or more optical lenses;
An image sensor on which an optical image is formed by the optical lens;
A lens holder that holds the optical lens movably in the optical axis direction;
A driving member formed by laminating piezoelectric elements extending in a plate shape in the thickness direction;
A drive head provided at the approximate center in the longitudinal direction of the surface layer of the drive member;
A moving body that contacts the driving head and receives the driving force to move the lens holding body in the optical axis direction;
A moving body pressing spring that urges the moving body in a point-contact manner from a direction perpendicular to the moving direction of the moving body,
The movable body is sandwiched between the drive heads of the pair of drive members and extends in the longitudinal direction of the drive members,
The moving body pressing spring urges the moving body in a direction of pressing either of the pair of drive heads,
The moving member is moved in the longitudinal direction by the driving head that performs pseudo-circular movement with the longitudinal direction of the moving body as a tangent by the driving member, and the lens holding body is moved in the optical axis direction.

In addition, mobile terminals incorporating this camera module
An image sensor on which an optical image is formed by the optical lens;
A lens holder that holds the optical lens movably in the optical axis direction;
A driving member formed by laminating piezoelectric elements extending in a plate shape in the thickness direction;
A drive head provided at the approximate center in the longitudinal direction of the surface layer of the drive member;
A moving body that contacts the driving head and receives the driving force to move the lens holding body in the optical axis direction;
A moving body pressing spring that urges the moving body in a point-contact manner from a direction perpendicular to the moving direction of the moving body,
The movable body is sandwiched between the drive heads of the pair of drive members and extends in the longitudinal direction of the drive members,
The moving body pressing spring urges the moving body in a direction of pressing either of the pair of drive heads,
A camera module that moves the moving body in the longitudinal direction by the drive head that performs pseudo-circular movement with the longitudinal direction of the moving body as a tangent by the driving member, and moves the lens holding body in the optical axis direction;
A case body to which the camera module is mounted;
It is provided in this case body and has an operation part which operates the camera module.

  In this way, the movable body is moved between the pair of drive heads that sandwich the movable body by sandwiching the movable body between the drive heads and making point contact with the movable body pressing spring from a direction perpendicular to the moving direction of the movable body. It can be configured to be held by a body pressing spring, and no other holding mechanism is required, so that the frictional force is reduced accordingly, and a small driving mechanism that can effectively use the driving force by the piezoelectric element can be configured.

  Further, as shown in Patent Documents 5 and 6, when the moving body is sandwiched by the drive head, the force for moving the moving body becomes stable and strong, and the moving body can be moved as much. Therefore, by moving the moving body in the optical axis direction by moving the moving body with the drive mechanism configured as described above, the rotor and the lens holding section can be moved like the camera module shown in Patent Documents 1 and 2. On the other hand, since a shaft member or the like that is substantially symmetrical and arranged in parallel is unnecessary, the camera module and the portable terminal including the camera module can be configured to be small and lightweight.

  The pair of drive heads are disposed at positions that are substantially parallel to the surface of the movable body with which each of the drive heads abuts and are substantially symmetric with respect to a plane that passes through the center of the movable body. The pressing spring is in point contact on both sides of the moving body extending direction at the contact portion between the driving head and the moving body, so that the moving body includes a pair of driving heads sandwiching the moving body, and one driving head. It is held by a moving body pressing spring that is in point contact on both sides of the moving body extending direction at the abutting portion with the moving body, and can be stably driven by the driving head of the piezoelectric element without any other holding mechanism. it can. Accordingly, since there are few portions that come into contact with the moving body, a small driving mechanism that can effectively use the driving force by the piezoelectric element by reducing the frictional force can be configured, and the camera module and the portable terminal equipped with the camera module can be reduced in size. It can be made lightweight.

  The pair of drive heads are arranged at positions that are substantially parallel to the surface of the moving body with which each of the drive heads abuts and are not symmetrical with respect to a plane passing through the center of the moving body, Is a point contact portion on one side of the moving body extending direction on the same plane as the contact portion of the one driving head with the moving body, and the other driving head is a point contact portion with the moving body of the moving body pressing spring. Are arranged at positions corresponding to the contact portions of the one drive head with the moving body, so that the moving body includes a pair of driving heads sandwiching the moving body and a moving body pressing spring 3. Even if there is no other holding mechanism, it can be stably driven by the driving head of the piezoelectric element, and the frictional force can be reduced to effectively use the driving force by the piezoelectric element. A small drive mechanism can be configured. Accordingly, since there are few portions that come into contact with the moving body, a small driving mechanism that can effectively use the driving force by the piezoelectric element by reducing the frictional force can be configured, and the camera module and the portable terminal equipped with the camera module can be reduced in size. It can be made lightweight.

  Furthermore, since the drive head is configured to be in line contact with the moving body, the friction area between the drive head and the moving body increases, the sliding torque increases, and the loss of driving force decreases. The holding force at the time of stop can also be strengthened.

  The moving body is disposed in a direction in which the longitudinal direction is substantially perpendicular to the optical axis direction, is fixed to the lens holding body, and has a cam slope having an inclination with respect to a plane orthogonal to the optical axis direction. The movable body further comprises a contact portion for the cam slope provided in the movable body, and a biasing means for biasing the lens holding body in a direction in which the cam slope and the movable body abut. Since the lens holding body moves in the optical axis direction when the abutting portion comes into contact with the cam slope, the lens holding body can be moved in the optical axis direction with a simple configuration.

  In the camera module, a guide shaft parallel to the optical axis is installed at one of the four corners of the camera module housing, and the lens holder has a guide hole through which the guide shaft is inserted. It is a preferred embodiment of the present invention to enable movement in the optical axis direction.

  As described above, the driving mechanism using the piezoelectric element according to the present invention sandwiches the moving body between the driving heads, and makes the moving body pressing spring point contact from a direction perpendicular to the moving direction of the moving body. The moving body can be configured to be held by a pair of drive heads sandwiching the moving body and a moving body pressing spring, and the other holding mechanism becomes unnecessary, and the frictional force is reduced accordingly, and the driving force by the piezoelectric element is reduced. It is possible to configure a small drive mechanism that can effectively utilize.

  Further, when the moving body is sandwiched by the drive head, the force for moving the moving body becomes stable and strong, and the moving body can be moved more strongly. Therefore, by moving the moving body in the optical axis direction by moving the moving body with the driving mechanism configured as described above, the optical axis direction is substantially symmetric with respect to the rotor and the lens holding portion as in the prior art, and parallel to the optical axis. Since a plurality of guide shafts and the like arranged in the above are unnecessary, the camera module and the mobile terminal including the camera module can be configured to be small and light.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples.

  1A is a top view, FIG. 1B is a right side view, FIG. 1C is a front view, and FIG. 1D is an external perspective view of a camera module 1 according to an embodiment of Example 1. FIG. 3 is an exploded perspective view of the camera module 1. Hereinafter, the description of the camera module 1 according to the embodiment will be described by taking an autofocus mechanism of the camera module 1 having a single-focus optical lens system as an example. However, the present invention is not limited thereto, and can be applied to a zoom lens or the like. it is obvious.

  In FIG. 1, the camera module 1 is formed in a substantially rectangular shape, and has a cover 5 having an opening for exposing the lens 20 of the lens unit 2 on the upper surface thereof, and a driving mechanism for moving the lens unit 2 in the optical axis direction. 3 and a drive mechanism frame 4 in which a sensor unit 6 having an image sensor such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) is disposed at the bottom.

  FIG. 2 is an exploded perspective view of the camera module 1. Each component will be described in order from the top. 5 is a cover that covers the upper surface of the camera module 1, 2 is a lens unit, and a guide shaft hole through which the guide shaft 41 is inserted. Is provided so as to project in the direction of the guide shaft 41, and in order to move the lens unit 2 in the optical axis direction, it extends in the installation direction of the piezoelectric elements (drive members) 31, 32 and extends in the optical axis direction. An inclined cam slope 22 and the like are integrated with a surface orthogonal to the angle.

  A drive mechanism 3 includes a pair of piezoelectric elements (drive members) 31 and 32, an interlocking lever (moving body) 33, a lever pressing spring 34 that presses the contact portion 330 of the interlocking lever 33 in the cam slope 22 direction, and a piezoelectric element. It comprises a piezoelectric element biasing spring 35 or the like that presses 32 toward the interlocking lever 33 side. Among these, the piezoelectric elements 31 and 32 and the interlocking lever (moving body) 33 are extended in a direction orthogonal to the optical axis of the lens 20, and the drive heads 310 and 320 are located at approximately the center in the longitudinal direction of each of the piezoelectric elements 31 and 32. Is provided so as to sandwich the interlocking lever 33. Then, when the interlocking lever 33 moves in the extending direction, the contact portion 330 provided so as to project in the cam slope 22 direction pushes the cam slope 22 and moves the lens unit 2 in the optical axis direction. It is.

  In addition, the drive mechanism frame 4 guides the movement of the lens unit 2 in the optical axis direction of the piezoelectric element accommodating portion 43 accommodating the piezoelectric element biasing spring 35 and the piezoelectric element 32, and the lens unit 2 is brought into contact with the interlocking lever 33. A sensor having a guide shaft 41 through which a spring 42 that presses in the direction of the contact portion 330 is inserted, and an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) at the bottom of the figure. The unit 6 is fitted.

  As shown in Patent Documents 5 and 6, the piezoelectric elements 31 and 32 constituting the drive mechanism 3 are formed in a plate shape and stacked in the thickness direction, and are driven approximately in the center in the longitudinal direction on the surface layer. The head provided with the heads 310 and 320 is used, and FIG. 8 is used to explain the structure of the piezoelectric element and how the piezoelectric element behaves when a voltage is applied.

  In FIG. 8A, reference numeral 120 denotes a piezoelectric element (driving member) in which plate-like piezoelectric elements 121 and 122 are laminated, and a driving head 123 formed, for example, in a semi-elliptical column shape at the approximate center in the longitudinal direction of one surface layer. Is provided. Reference numerals 124 and 125 denote support portions made of an elastic body for pressing the semi-elliptical prism-shaped drive head 123 against a driven body (not shown).

  Then, Vcc is applied to the entire surface of the piezoelectric element 121 on the side of the piezoelectric element 120 on which the semi-elliptical column-shaped drive head 123 is provided, and the entire surface of the surface of the piezoelectric element 122 on the opposite side is set to Gnd (ground). When a traveling wave having a phase shifted by π / 2 as shown in (F) is applied to A and B at both ends in the longitudinal direction, the voltage applied to the both ends A and B by the piezoelectric element 120 (B ), When A = Vcc and B = Vcc, the semi-elliptical prism-shaped drive head 123 side is convex, and when A = Vcc and B = Gnd as shown in FIG. The left side of the head 123 is convex and the right side is concave. When A = Gnd and B = Gnd as shown in (D), the semi-elliptical prism-shaped drive head 123 side is concave, and as shown in FIG. = Gnd, B = Vcc, semi-elliptical column Left concave than Jo driver head 123 and the right side is a convex vertex of the semi-elliptic cylinder shape drive head 123 performs pseudo circular motion. Note that the pseudo circular motion referred to here refers to a motion that draws a similar locus such as an ellipse or a polygon, although it is not a complete circle.

  For this reason, a driven body (not shown) to which the semi-elliptical cylinder-shaped driving head 123 is pressed is sent to either the left or right side of the drawing. In this case, if the direction of the traveling wave shown in FIG. 8F is reversed, the direction of the pseudo circular motion is reversed and the driven body is sent in reverse. If the semi-elliptical prism-shaped drive head 123 has a shape and structure that makes line contact with the driven body, the friction area increases, the sliding torque is large, the loss of driving force is small, and the holding force at the time of stopping is also high. It can be set as the drive mechanism which can be strengthened. In addition, a larger effect can be expected by increasing the surface roughness of the portion of the driven body that is in contact with the semi-elliptical column-shaped driving head 123 and increasing the friction coefficient. Further, the traveling wave to be applied is not limited to a sine wave, but a rectangular wave. A wave, a triangular wave, etc. may be sufficient.

In FIG. 9, two drive members composed of the plate-like piezoelectric elements 121 and 122 having the drive head 123 provided at the center in the longitudinal direction are prepared, and the drive heads 123 ₁ and 123 _{2 of the} respective drive members are prepared. FIG. 5 is a conceptual diagram when the moving body 126 is disposed so as to be symmetrical with respect to a central plane parallel to the contact surface of the driving heads 123 ₁ and 123 _{2 in} the moving body 126. FIG. By applying a traveling wave whose phase is shifted by π / 2 as described in FIG. 8, a force for moving the moving body 126 in the direction of the arrow 127 or the arrow 128 is applied synchronously from both sides of the moving body 126. Therefore, the driving member can be stable and strong.

  The above is the operation principle of the piezoelectric element used in the drive mechanism 3 of the camera module 1 of the embodiment. Next, the configuration of the camera module 1 will be described in more detail with reference to FIG. 3A is a cross-sectional view as viewed from the direction indicated by the arrow AA ′ in FIG. 1, FIG. 3B is a cross-sectional view as viewed from the direction indicated by the arrow BB ′, and FIG. Is a cross-sectional view seen from the arrow direction at the CC ′ position, and (D) is a cross-sectional view seen from the arrow direction at the DD ′ position.

  First, FIGS. 3A and 3C are cross-sectional views as viewed from the direction indicated by arrows AA ′ and CC ′ in FIG. 1, and these two cross-sectional views show the same cross-section from both sides. There is a relationship that I saw. First, FIG. 3A shows a state in which the interlocking lever 33 is pressed by the lever pressing spring 34 and a contact state of the contact portion 330 with the cam slope 22 as viewed from the lens unit 2. FIG. These show the state seen from the piezoelectric elements 31 and 32 side. That is, the interlocking lever 33 extends in the longitudinal direction of the piezoelectric elements 31 and 32 extending in a direction orthogonal to the optical axis, and as described with reference to FIG. 9, the driving head 310 disposed on the piezoelectric elements 31 and 32. , 320 is sandwiched at a position that is symmetric with respect to the center plane parallel to the contact surface of the drive head 310, 320 in the interlocking lever 33. Further, the lever pressing protrusion 341 of the lever pressing spring 34 makes point contact at two locations on both sides in the extending direction of the interlocking lever 33 at the contact portion between the driving head 310 and the interlocking lever 33 to press the interlocking lever 33, and the cam A contact portion 330 protruding in the direction of the slope 22 is urged in the direction of the cam slope 22.

  The cam slope 22 is formed integrally with the lens unit 2 and has an inclination with respect to a plane perpendicular to the optical axis direction. In this case, as an example, the cam slope 22 extends from the driving heads 310 and 320. The slope is a direction closer to the sensor unit 6 as the distance increases. Therefore, when the contact portion 330 of the interlocking lever 33 moves in the direction approaching the drive heads 310 and 320, the slope 22 is pushed down to move the lens unit 2 toward the sensor unit 6. Conversely, when the lens unit 2 is moved away from the drive heads 310 and 320, the lens unit 2 is moved away from the sensor unit 6 by the pressing force of the spring 42. Of course, the inclination of the cam slope 22 may be reversed.

  FIG. 3B is a cross-sectional view seen from the direction of the arrow at the position BB ′ in FIG. 1, and the pressing state of the interlocking lever 33 by the lever pressing spring 34 and the contact portion, as in FIG. 330 shows the state of contact of the cam slope 22 with the cam slope 22, the accommodation state of the piezoelectric element 32 in the piezoelectric element accommodation portion 43 provided in the drive mechanism frame 4, and the piezoelectric element accommodation portion 52 provided in the cover 5. The housing state of the piezoelectric element 31 and the fitting state with the guide shaft 41 that is provided on the drive mechanism frame 4 and presses the lens unit 2 toward the subject by the spring 42 and is fitted to the bearing portion 21 are shown. ing.

  The lever pressing spring 34 is accommodated on the optical axis side of the piezoelectric element 31 with the extending direction of the piezoelectric element 31 as the longitudinal direction, and a lever pressing projection 341 is provided on a piece protruding toward the interlocking lever 33 side. The interlocking lever 33 is pressed toward the sensor unit 6 by the protrusion 341. The contact portion 330 of the interlocking lever 33 protrudes from the interlocking lever 33 toward the cam slope 22 and moves while contacting the cam slope 22. The piezoelectric element biasing spring 35 is accommodated in the piezoelectric element accommodating portion 43 and presses the piezoelectric element 32 toward the interlocking lever 33 side.

  FIG. 3D shows a pressing state of the interlocking lever 33 by the lever pressing spring 34 toward the sensor unit 6 and a pressing state of the piezoelectric element 32 toward the interlocking lever 33 by the piezoelectric element biasing spring 35. It is sectional drawing. 3D is a cross-sectional view as viewed from the direction indicated by the arrow DD ′ in FIG. 1. The piezoelectric element 31 is regulated in the longitudinal direction by the piezoelectric element housing portion 52 in the cover 5. However, the piezoelectric element supporting projection 51 provided in the piezoelectric element accommodating portion 52 is supported and accommodated at two points. The piezoelectric element 32 is regulated in the longitudinal direction by a piezoelectric element housing portion 43 provided in the drive mechanism frame 4 and is supported at two points by a piezoelectric element pressing projection 351 provided in the piezoelectric element biasing spring 35 while being interlocked. It is pressed to the 33 side.

  The interlocking lever 33 is symmetric with respect to the center plane parallel to the contact surface of the driving heads 310 and 320 in the interlocking lever 33 by the driving heads 310 and 320 disposed on the piezoelectric elements 31 and 32 as described above. It is sandwiched at various positions.

  Therefore, as is apparent from the cross-sectional views of FIGS. 3A to 3D, the interlocking lever 33 is sandwiched between the drive heads 310 and 320 and the contact portion 330 is in contact with the slope 22; Since two points are pressed by the lever pressing protrusions 341 of the lever pressing spring 34 and supported at a total of five points, a structure similar to a bearing for holding the interlocking lever 33 is not particularly required. Further, the interlocking lever 33 is in contact with the drive heads 310 and 320 in which the rubbing portions are in line contact with each other when moved in the longitudinal direction, and the two lever pressing protrusions 341 and the slope 22 in the lever pressing spring 34. 330, and the contact area of each is very small, so that it can move with a small force.

  FIG. 4 shows only the driving mechanism 3 and the lens unit 2 taken out and shown in an easy-to-understand manner. FIG. 4 is a diagram showing only the lens unit 2 and its optical axis direction moving mechanism 3 in the camera module 1 according to the embodiment of Example 1 shown in FIG. 1, and (A) is provided in the lens unit 2. The top view which showed the relationship of the cam slope 22 and the interlocking lever 33 which were done, (B) is the top view which added the lever pressing spring 34 and the piezoelectric element 31 which presses the interlocking lever 33 in the state of (A), (C) is It is a front view of the state shown to (B).

  As shown in FIG. 4A, the lens unit 2 includes a bearing portion 21 in a part thereof, and the extending direction of the interlocking lever 33 inclined with respect to the plane orthogonal to the optical axis direction as described above. That is, the cam slope 22 in a direction approaching the sensor unit 6 as the distance from the drive heads 310 and 320 is integrally formed. In the interlocking lever 33, the drive head 310 of the piezoelectric element 31 is in contact with the position 310 indicated by the oblique lines, and the lever pressing protrusion 341 of the lever pressing spring 34 is in contact with the position 341.

  4B is a top view in which a lever pressing spring 34 for pressing the interlocking lever 33 and the piezoelectric element 31 are added to the state of FIG. 4A, and the lever pressing spring 34 is provided on the lens unit 2 side of the piezoelectric element 31. FIG. Then, the lever pressing projection 341 contacts and presses the interlocking lever 33 toward the driving head 320. 4C is a front view of the state shown in FIG. 4B. In addition to the configuration described above, the piezoelectric element 32 is moved toward the interlocking lever 33 by the piezoelectric element pressing protrusion 351 of the piezoelectric element biasing spring 35. FIG. A pressed state is shown.

  FIGS. 5A and 5B show how the lens unit 2 moves in the optical axis direction by the drive mechanism 3 using a piezoelectric element in the camera module 1 of the embodiment configured as described above. . First, FIG. 5 (A) shows a state in which the contact portion 330 of the interlocking lever 33 is closest to the drive head 310, 320 side, as is apparent from FIGS. 3 (A), (B), (C). The abutment portion 330 of the interlocking lever 33 is located closest to the drive heads 310 and 320 in the cam slope 22 against the elastic force of the spring 42 provided on the guide shaft 41, and the lens unit integrated with the cam slope 22. 2 is the state most pushed to the sensor unit 6 side.

  Then, the piezoelectric elements 31 and 32 are driven from this state, and the interlocking lever 33 moves in the extending direction by causing the drive heads 310 and 320 to perform a pseudo circular motion as described in FIGS. FIG. 5B shows that the contact portion 330 of 33 is most distant from the drive heads 310 and 320. In this state, as is apparent from FIGS. 3A and 3C, the contact portion 330 of the interlocking lever 33 is located farthest from the drive heads 310 and 320 on the cam slope 22 and is provided on the guide shaft 41. The lens unit 2 integrated with the cam slope 22 by the elastic force of the spring 42 is positioned farthest from the sensor unit 6.

  In this way, by driving the piezoelectric elements 31 and 32, the lens unit 2 moves in the optical axis direction, and the lens unit 2 can be moved in accordance with, for example, autofocus or zooming with a small and simple configuration. Become.

  The above is the first example of the camera module 1 according to the embodiment. In the camera module 1 of the first example, as is clear from the cross-sectional views of FIGS. A total of five points 33 are sandwiched between the drive heads 310 and 320 and the contact portion 330 is in contact with the slope 22 and the lever pressing protrusion 341 of the lever pressing spring 34 is pressed at two locations. It is supported by. Therefore, a structure similar to a bearing for holding the interlocking lever 33 is not particularly required, and the portions that rub when the interlocking lever 33 moves in the longitudinal direction are in the drive heads 310 and 320 that are in line contact and the lever pressing spring 34. Only the lever pressing projections 341 and the contact portions 330 that are in contact with the slope 22 are provided, and each contact area is very small and can be moved with a small force.

  However, when the interlocking lever 33 is moved in the extending direction by the pseudo circular motion of the driving heads 310 and 320 of the piezoelectric elements 31 and 32, the driving force by the driving heads 310 and 320 is smaller when the frictional parts are reduced as much as possible. I'll do it. The camera module of Example 2 shown in FIGS. 6 and 7 is configured in consideration of this point.

  6 is a perspective view of the lens unit 2 and its optical axis direction moving mechanism in the camera module according to the embodiment of Example 2. FIG. 7 is a perspective view of the lens unit 2 and its optical axis direction moving mechanism. It is a top view, (B) is a front view, (C) is a cross-sectional view as viewed from the direction indicated by the arrow EE ′ in (A). As described above, in the following description, the camera module according to the embodiment will be described by taking the autofocus mechanism of the camera module 2 having a single-focus optical lens system as an example. However, the present invention is not limited thereto, and the zoom lens It is clear that it can be applied to the above.

  In the figure, reference numerals 71 and 72 denote the same piezoelectric elements as in the first embodiment, and the extending directions thereof are the same as those in the first embodiment, and drive heads 710 and 720 are provided substantially at the center in the extending direction. Reference numeral 74 denotes a lever pressing spring for pressing the interlocking lever 33, which is provided on the lens unit 2 side of the piezoelectric elements 71 and 72 as in the first embodiment. Unlike the first embodiment, the protrusion 741 is provided on a piece protruding only on the contact portion 330 side of the interlocking lever 33. Other components are the same as those of the camera module 1 of the first embodiment.

  In the camera module according to the second embodiment, as described above, the portion that rubs when moving the interlocking lever 33 in the extending direction by the pseudo circular motion of the drive heads 310 and 320 of the piezoelectric elements 31 and 32 is compared with the first embodiment. As is apparent from FIG. 6, the contact position of the drive heads 710 and 720 with the interlock lever 33 in the piezoelectric elements 71 and 72 is different from the case described with reference to FIG. 33 is not symmetrical with respect to the center plane parallel to the contact surface of the drive heads 710 and 720, but is shifted in the extending direction of the interlocking lever 33, and is driven to a position corresponding to the position between the lever pressing protrusion 741 and the drive head 710. The head 720 is provided.

  That is, the interlocking lever 33 is sandwiched between the drive heads 310 and 320 as described in FIG. 3 in the first embodiment, the abutting portion 330 abuts against the slope 22, and the lever pressing projection 341 of the lever pressing spring 34. Two places are pressed and supported. This is because the driving heads 310 and 320 in the interlocking lever 33 are in contact with each other at a symmetrical position with respect to the center plane parallel to the contact surface to the interlocking lever 33. The abutment portion 330 does not have a pressing force toward the cam slope 22, and the slope 22 pushes up the abutment portion 330 by the spring 42 to prevent the interlocking lever 33 from tilting and generating a load. The pressure is obtained by lever pressing protrusions 341 provided at two positions of the lever pressing spring 34.

  In contrast to this, in the second embodiment shown in FIGS. 6 and 7, the contact position of the drive heads 710 and 720 on the piezoelectric elements 71 and 72 with respect to the interlocking lever 33 is different from the case described with reference to FIG. The drive heads 710, 720 are not symmetrical with respect to the center plane parallel to the contact surface of the drive heads 710, 720, and are shifted in the extending direction of the interlocking lever 33. be able to. Therefore, in the second embodiment, the lever pressing protrusion 741 provided on the lever pressing spring 74 presses the interlocking lever 33 only at one point only for the contact portion 330 to always contact the cam slope 22. It has become.

  Accordingly, the interlocking lever 33 is supported by four points of the driving heads 710 and 720, the lever pressing protrusion 741, and the contact portion 330 that is in contact with the slope 22, and holds the interlocking lever 33 as in the first embodiment. Since a structure similar to a bearing is not required and is supported at four points, which is smaller than that of the first embodiment, the contact area is reduced accordingly, and the apparatus can be moved with a smaller force.

  More specifically, as shown in FIGS. 6 and 7, the piezoelectric element 71 has a driving head 710 in a direction opposite to the contact portion 330 with respect to the position of the driving head 720 of the piezoelectric element 72. The lever pressing spring 74 is disposed on the lens unit 2 side of the piezoelectric element 71 and is disposed only in the direction of the abutting portion 330 of the interlocking lever 33 with the lever pressing projection 741 (see FIGS. 6 and 7B). Is pressed. However, the piezoelectric element biasing spring 35 presses the piezoelectric element 72 in the direction of the interlocking lever 33 with the piezoelectric element pressing protrusions 351 provided at two places as in the first embodiment.

  FIG. 7A is a top view showing the arrangement of these drive mechanisms. As in the case of the first embodiment, the lens unit 2 projects in the direction of the guide shaft 41 and the cam slope 22 Is provided. The lever pressing spring 74 is provided between the piezoelectric element 71 and the lens unit 2.

  FIG. 7B is a front view of FIG. 7A, showing the arrangement of the piezoelectric elements 71 and 72 having the drive heads 710 and 720, the lever pressing spring 74, the lever pressing protrusion 741, the piezoelectric element biasing spring 35, The state of the piezoelectric element pressing protrusion 351 and the like is shown. 7C is a cross-sectional view of FIG. 7A viewed from the direction indicated by the arrow EE ′, and further shows a state in which the interlock lever 33 is pressed by the lever pressing protrusion 741 of the lever pressing spring 74. ing.

  FIG. 10 is a diagram showing a mobile phone 100 as an example of a mobile terminal incorporating the camera module described above. 10A shows a state in which the display unit 101 is closed and the lens unit 103 of the camera module 1 or 6 can be seen, and FIG. 10B shows an operation button 111 provided on the operation unit 110 by opening the display unit 101. It shows the state that can be operated.

  In the figure, reference numeral 102 denotes a first display device that displays various types of information when the operation button 111 provided on the operation unit 110 is in the state (B), and 104 is an operation button as shown in FIG. Reference numeral 112 denotes a second display device that notifies an incoming mail or the like when 111 is in an inoperable state, and 112 is a hinge mechanism for opening and closing the display unit 101 and the operation unit 110. Among these, the display part 101 and the operation part 110 each comprise a case body.

  The display unit 101 is provided with a hole for exposing the lens unit 2 of the camera module described above at the position indicated by 103, and the main body of the camera module is accommodated therein. Then, when a predetermined operation button 111 of the operation unit 110 is operated, an image is taken by the camera module, and the taken image is displayed on the first display device 102, for example. Although not shown, the operation unit 110 houses a battery, a communication unit, and the like, and the thickness of the display unit 101 is substantially regulated to the height of the camera module 1.

  As described above, according to the present embodiment, the driving mechanism that drives in the lens optical axis direction can be configured to be small and inexpensive, and the camera module that can be configured to be small and lightweight, and the portable terminal including the camera module are provided. Can be provided.

(A) of the camera module which becomes embodiment of Example 1 is a top view, (B) is a right view, (C) is a front view, (D) is an external perspective view. 1 is an exploded perspective view of a camera module according to an embodiment of Example 1. FIG. 1A is a cross-sectional view of a camera module according to an embodiment of Example 1, where FIG. 1A is a cross-sectional view as viewed from the direction indicated by arrows AA ′ in FIG. 1 and FIG. (C) is sectional drawing seen from the arrow direction of CC 'position, (D) is sectional drawing seen from the arrow direction of DD' position. FIG. 2 is a diagram showing only the lens unit and its optical axis direction moving mechanism in the camera module according to the embodiment of the first embodiment shown in FIG. 1, and (A) shows the cam slope 22 and the interlocking lever 33 provided in the lens unit. Top view showing the relationship, (B) is a top view in which the lever pressing spring 34 and the piezoelectric element 31 are added to the state of (A), and (C) is a front view of the state shown in (B). It is. 2A and 2B are perspective views of a lens unit of a camera module and an optical axis direction moving mechanism thereof according to an embodiment of Example 1, and FIGS. It shows how it moves. It is a perspective view of the lens unit of the camera module which becomes embodiment of Example 2, and its optical axis direction moving mechanism. (A) is a top view, (B) is a front view, and (C) is a EE ′ position in (A) of the lens unit of the camera module and its optical axis direction moving mechanism according to the embodiment of Example 2. It is sectional drawing seen from the arrow direction. , It is a figure for demonstrating the structure outline of the piezoelectric element (driving member) which comprises the drive mechanism using the piezoelectric element which becomes embodiment, and how a piezoelectric element behaves by voltage application. It is a conceptual diagram when two drive members composed of a plate-like piezoelectric element provided with a drive head at the approximate center in the longitudinal direction are prepared, and the drive head of each drive member is sandwiched between moving bodies. It is a figure which shows schematically the form telephone as an example of the portable terminal with which the camera module of embodiment was incorporated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera module 2 Lens unit 20 Lens 21 Bearing part 22 Cam slope 3 Drive mechanism 31, 32 Piezoelectric element 310, 320 Drive head 33 Interlocking lever 330 Contact part 34 Lever pressing spring 341 Lever pressing protrusion 35 Piezo element biasing spring 351 Piezoelectric Element pressing protrusion 4 Driving mechanism frame 41 Guide shaft 42 Spring 43 Piezoelectric element housing part 5 Cover 51 Piezoelectric element supporting protrusion 52 Piezoelectric element housing part 6 Sensor units 71 and 72 Piezoelectric elements 710 and 720 Driving head 74 Lever pressing spring 741 Lever pressing protrusion

Claims (11)

A driving member formed by laminating piezoelectric elements extending in a plate shape in the thickness direction;
A drive head provided at the approximate center in the longitudinal direction of the surface layer of the drive member;
A moving body that contacts the driving head and moves by receiving a driving force;
A moving body pressing spring that urges the moving body in a point-contact manner from a direction perpendicular to the moving direction of the moving body,
The movable body is sandwiched between the drive heads of the pair of drive members and extends in the longitudinal direction of the drive members,
The moving body pressing spring urges the moving body in a direction of pressing either of the pair of drive heads,
A driving mechanism using a piezoelectric element, characterized in that the driving member moves the moving body in the longitudinal direction by the driving head that performs pseudo-circular movement with the longitudinal direction of the moving body as a tangent by the driving member. The pair of drive heads is disposed at a position that is substantially parallel to a surface of the moving body with which each of the drive heads abuts and is substantially symmetric with respect to a surface passing through the center of the moving body,
2. The drive mechanism using a piezoelectric element according to claim 1, wherein the moving body pressing spring is in point contact on both sides of the moving body extending direction at a contact portion between the driving head and the moving body. The pair of driving heads are arranged at positions that are substantially parallel to the surface of the moving body with which each of the driving heads abuts and are not symmetrical with respect to a surface passing through the center of the moving body,
The movable body pressing spring is in point contact with one side of the moving body extending direction on the same plane as the contact portion of the one driving head with the moving body, and the other driving head is a moving body of the movable body pressing spring. The drive mechanism using the piezoelectric element according to claim 1, wherein the drive mechanism is disposed at a position corresponding to a point contact portion between the first drive head and the moving portion of the one drive head. .   The drive mechanism using a piezoelectric element according to any one of claims 1 to 3, wherein the drive head is configured to be in line contact with the moving body. At least one or more optical lenses;
An image sensor on which an optical image is formed by the optical lens;
A lens holder that holds the optical lens movably in the optical axis direction;
A driving member formed by laminating piezoelectric elements extending in a plate shape in the thickness direction;
A drive head provided at the approximate center in the longitudinal direction of the surface layer of the drive member;
A moving body that contacts the driving head and receives the driving force to move the lens holding body in the optical axis direction;
A moving body pressing spring that urges the moving body in a point-contact manner from a direction perpendicular to the moving direction of the moving body,
The movable body is sandwiched between the drive heads of the pair of drive members and extends in the longitudinal direction of the drive members,
The moving body pressing spring urges the moving body in a direction of pressing either of the pair of drive heads,
A camera module, wherein the moving member is moved in the longitudinal direction by the driving head that performs a pseudo circular motion with the longitudinal direction of the moving body as a tangent by the driving member, and the lens holder is moved in the optical axis direction. . The moving body is arranged in a direction in which the longitudinal direction is substantially perpendicular to the optical axis direction,
A cam slope fixed to the lens holder and having an inclination with respect to a plane perpendicular to the optical axis direction;
An abutting portion to the cam slope provided on the movable body;
Biasing means for biasing the lens holding body in a direction in which the cam slope and the moving body abut;
The camera module according to claim 5, further comprising:   The camera module according to claim 5, wherein the driving head is configured to be in line contact with the moving body.   In the camera module, a guide shaft parallel to the optical axis is installed at any one of the four corners of the camera module housing, and the lens holder has a guide hole through which the guide shaft is inserted. 8. The camera module according to claim 5, wherein the camera module can be moved in an axial direction. The pair of drive heads is disposed at a position that is substantially parallel to a surface of the moving body with which each of the drive heads abuts and is substantially symmetric with respect to a surface passing through the center of the moving body,
9. The camera module according to claim 5, wherein the moving body pressing spring is in point contact at both sides of the moving body extending direction at a contact portion between the driving head and the moving body. The pair of driving heads are arranged at positions that are substantially parallel to the surface of the moving body with which each of the driving heads abuts and are not symmetrical with respect to a surface passing through the center of the moving body,
The movable body pressing spring is in point contact with one side of the moving body extending direction on the same plane as the contact portion of the one driving head with the moving body, and the other driving head is a moving body of the movable body pressing spring. 9. The camera module according to claim 5, wherein the camera module is disposed at a position corresponding to a point contact portion between the first drive head and the moving portion of the one drive head. . At least one or more optical lenses;
An image sensor on which an optical image is formed by the optical lens;
A lens holder that holds the optical lens movably in the optical axis direction;
A driving member formed by laminating piezoelectric elements extending in a plate shape in the thickness direction;
A drive head provided at the approximate center in the longitudinal direction of the surface layer of the drive member;
A moving body that contacts the driving head and receives the driving force to move the lens holding body in the optical axis direction;
A moving body pressing spring that urges the moving body in a point-contact manner from a direction perpendicular to the moving direction of the moving body,
The movable body is sandwiched between the drive heads of the pair of drive members and extends in the longitudinal direction of the drive members,
The moving body pressing spring urges the moving body in a direction of pressing either of the pair of drive heads,
A camera module that moves the moving body in the longitudinal direction by the drive head that performs pseudo-circular movement with the longitudinal direction of the moving body as a tangent by the driving member, and moves the lens holding body in the optical axis direction;
A case body to which the camera module is mounted;
A portable terminal comprising an operation unit provided on the case body and operating the camera module.

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