JP2008187839A - Drive mechanism using piezoelectric element, camera module using the drive mechanism, and portable terminal equipped with the camera module - Google Patents

Abstract

A compact driving mechanism using a piezoelectric element, a camera module and a portable terminal using the driving mechanism are provided.
A drive head (310, 320) is provided at substantially the center in the longitudinal direction of drive members (31, 32) in which piezoelectric elements extending in a plate shape are stacked in the thickness direction, and an interlock lever (33) is sandwiched between them. The cam slope 22 is brought into contact with the head. Among these, the drive head 320 is provided on the contact side of the interlocking lever 33 with the cam slope 22, and the drive head 310 is provided at a position corresponding to between the drive head 320 and the cam slope 22 with the interlocking lever 33 interposed therebetween. Accordingly, the driving heads 310 and 320 and the cam slope 22 support the interlocking lever 33 at three points, and the driving levers 31 and 32 drive the cam slope 22 and the interlocking lever 33 extends. It was made to move in the direction orthogonal to the current direction.
[Selection] Figure 2

Description

  The present invention relates to a driving mechanism using a piezoelectric element, a camera module used in a portable terminal such as a mobile phone using the driving mechanism, and a portable terminal including the camera module, and more particularly, a piezo element (PZT) or the like. The present invention relates to a small-sized drive mechanism using the piezoelectric element, a small-sized camera module that moves the lens in the optical axis direction using the drive mechanism, and a portable terminal equipped with the camera module. is there.

  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 shaft members 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 member, and the lens holding part is moved relative to the shaft member by driving the piezo element to It can be driven in the axial 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 movable body that is sandwiched between the drive heads of the pair of drive members, extends in the longitudinal direction of the drive member, and moves by receiving a drive force from the drive head;
A cam slope in contact with one end of the moving body;
An elastic member for pressing one drive head of the pair of drive heads toward the moving body;
An elastic member that presses the cam slope toward the moving body,
The one drive head is provided on a side of the movable body in contact with the cam slope, and the other drive head is located on the opposite side of the one drive head across the movable body and the one drive head and the cam slope. Is located at the corresponding position between
The movable body is supported at three points by the pair of drive heads and the cam slope, and the movable body is moved in the longitudinal direction by driving the pair of drive members, so that the cam slope is extended by the movable body. It moves to the direction orthogonal to a direction, It is characterized by the above-mentioned.

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 cam slope fixed to the lens holder and having an inclination with respect to a surface perpendicular to the optical axis direction;
A driving member formed by laminating piezoelectric elements extending in a plate shape in the thickness direction, and forming the extending direction as a direction substantially orthogonal to the optical axis direction;
A drive head provided at the approximate center in the longitudinal direction of the surface layer of the drive member;
A movable body sandwiched between the drive heads of the pair of drive members and extending in the longitudinal direction of the drive member, one end of which is in contact with the cam slope;
An elastic member for pressing one drive head of the pair of drive heads toward the moving body;
An elastic member that presses the cam slope toward the moving body;
Consists of
The one drive head is provided on a side of the movable body in contact with the cam slope, and the other drive head is located on the opposite side of the one drive head across the movable body and the one drive head and the cam slope. Is located at the corresponding position between
The lens holding body in which the moving body is supported at three points by the pair of driving heads and the cam slope, the moving body is moved in the longitudinal direction by driving the pair of driving members, and the cam slope is fixedly provided. It is characterized by moving in the optical axis direction.

In addition, mobile terminals incorporating this camera module
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 cam slope fixed to the lens holder and having an inclination with respect to a surface perpendicular to the optical axis direction;
A drive member formed by laminating piezoelectric elements extending in a plate shape in the thickness direction, and forming the extending direction as a direction substantially orthogonal to the optical axis direction;
A drive head provided at the approximate center in the longitudinal direction of the surface layer of the drive member;
A movable body sandwiched between the drive heads of the pair of drive members and extending in the longitudinal direction of the drive member, one end of which is in contact with the cam slope;
An elastic member for pressing one drive head of the pair of drive heads toward the moving body;
An elastic member that presses the cam slope toward the moving body,
The one drive head is provided on a side of the movable body in contact with the cam slope, and the other drive head is located on the opposite side of the one drive head across the movable body and the one drive head and the cam slope. Is located at the corresponding position between
The lens holding body in which the moving body is supported at three points by the pair of driving heads and the cam slope, the moving body is moved in the longitudinal direction by driving the pair of driving members, and the cam slope is fixedly provided. A camera module that moves in the direction of the optical axis;
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, one end of the moving body is brought into contact with the cam slope, and further sandwiched between the pair of driving heads, one driving head is provided on the moving body in contact with the cam slope, and the other driving head holds the moving body. It is positioned at a corresponding position between the one drive head and the cam slope on the opposite side of the one drive head, and is supported by the pair of drive heads and the cam slope at three points. A mechanism for holding the movable body in any form is no longer necessary, 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.

  And 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 is increased, the sliding torque is increased, and the loss of driving force is reduced. The holding force at the time of stop can also be strengthened.

  The pair of driving members are supported at two points in the vicinity of both ends in the longitudinal direction of the surface opposite to the surface on which the driving head is provided, and the elastic member that presses the one driving head toward the moving body is By serving also as a member that supports the two driving members, a pair of driving members can be supported without providing a special supporting member.

  Further, the camera module has guide shafts parallel to the optical axis installed at any 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 that the optical axis direction movement can be performed.

  As described above, in the driving mechanism using the piezoelectric element according to the present invention, the moving body is supported at three points by the driving head and the cam slope, and the other moving body holding mechanism is unnecessary, so the frictional force is reduced accordingly. Thus, it is possible to configure a small driving mechanism that can effectively use the driving force by the piezoelectric element.

  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 shaft members and the like arranged in the above are unnecessary, the camera module and the portable terminal including the camera module can be configured to be small and lightweight.

  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. 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 (not shown in FIG. 1), a sensor unit 6 (not shown in FIG. 1) in which an image pickup device such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) is arranged is accommodated in the lower part. And the drive mechanism frame 4.

  2 is an exploded perspective view of the camera module 1, FIG. 3 is a cross-sectional view of the camera module 1 as viewed from the direction of the arrow AA ′ in FIG. 1A, and FIG. 4 is a lens of the camera module according to the embodiment. (A) is a top view of a unit and its optical axis direction moving mechanism, and (B) is a cross-sectional view as seen from the direction of the arrow at the position BB ′ in (A). 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 the figure, the same components are assigned the same numbers. First, regarding the exploded perspective view of FIG. 2, each of the components will be described in order from the top. 5 is a cover that covers the upper surface of the camera module 1 as described above, 2 is a lens unit, and the lens 20 is accommodated in the center. A bearing portion 21 having a guide shaft hole inserted through the guide shaft 41 is provided on the side portion so as to protrude in the direction of the guide shaft 41, and the lens unit 2 is moved to the bearing portion 21 in the optical axis direction. Therefore, the cam slope 22 and the like extending in the same direction as the extending direction of the piezoelectric elements (drive members) 31 and 32 and having an inclination with respect to the plane orthogonal to the optical axis direction are integrated.

  Reference numeral 3 denotes a drive mechanism. The drive mechanism 3 includes a pair of piezoelectric elements (drive members) 31 and 32, an interlocking lever (moving body) 33, a piezoelectric element biasing spring 35 that presses the piezoelectric element 32 toward the interlocking lever 33, and the like. It consists of Among these elements, the piezoelectric elements 31 and 32 are provided with drive heads 310 and 320 at substantially the center in the longitudinal direction, and the interlocking lever 33 extends in a direction orthogonal to the optical axis of the lens 20. As will be described later, the drive heads 310 and 320 of the piezoelectric elements 31 and 32 are provided such that the drive head 320 is provided on the contact side of the interlocking lever 33 with the cam slope 22, and the drive head 310 sandwiches the interlocking lever 33. Thus, the piezoelectric elements 31 and 32 are arranged so as to be displaced from each other so as to be positioned at corresponding positions between the drive head 320 and the cam slope 22, and the interlocking lever 33 is sandwiched therebetween.

  Further, the cam slope 22 is pressed toward the interlocking lever 33 because the lens unit 2 is pressed in a direction away from the sensor unit 6 by the spring 42 while the interlocking lever 33 and the one end are in contact with each other. 33 is supported at three points by the drive heads 310 and 320 and the cam slope 22 and is kept parallel to the piezoelectric elements 31 and 32. Then, when the interlocking lever 33 moves in the extending direction, the cam slope 22 is pushed and the lens unit 2 is moved in the optical axis direction.

  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 moves the lens unit 2 away from the sensor unit 6. A sensor shaft 6 is provided with a guide shaft 41 through which a spring 42 that presses in the direction is inserted, and an image sensor such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) at the bottom of the figure. It is designed to be 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. A head provided with the heads 310 and 320 is used. The schematic structure of the piezoelectric element and how the piezoelectric element behaves when a voltage is applied will be described with reference to FIG.

  In FIG. 5A, 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 in, for example, a semi-elliptical column shape at the 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 (earth). 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 both ends A and B by the piezoelectric element 120 (B) As shown in FIG. 5, 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 Left concave from elliptical cylindrical shape drive head 123 and the right side becomes convex, the apex of the semi-elliptic cylinder shape drive head 123 performs pseudo circular motion. The pseudo-circular motion referred to here is not a complete circular motion, but refers to a motion that draws a similar locus such as an elliptical motion or a polygonal motion.

  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, when the direction of the traveling wave shown in FIG. 5F is reversed, the direction of the pseudo circular motion is reversed and the driven body is sent in the opposite direction. 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.

FIG. 6 is a conceptual diagram of the drive mechanism of the present invention using two drive members composed of the plate-like piezoelectric elements 121 and 122 having the drive head 123 provided at the approximate center in the longitudinal direction. In the drive mechanism shown in FIG. 6, the movable body 126 is sandwiched between the drive heads 123 ₁ and 123 ₂ provided substantially at the centers of the plate-like piezoelectric elements 121 and 122, respectively, and one end of the movable body 126 has an arrow 129 _1. A slope indicated by 127 having an angle with respect to the extending direction of the moving body 126 by applying a pressing force in the direction is provided. Although not shown in the drawings, each of the plate-like piezoelectric elements 121 and 122 is provided with at least one of the support portions indicated by 124 and 125 in FIG. 5A as an elastic body.

The drive head ₁₂₃ 1, 123 _2, this from 6 As is apparent, the driving head 123 ₁ is provided on the slope 127 side of the drive head 123 _2. For this reason, as described above, the pressing force in the direction of the arrow 129 ₁ is applied to the slope 127, so that the pressing force in the direction of the arrow 129 ₁ and the above-described FIG. The movable body 126 is supported at three points by the drive heads 123 ₁ , 123 ₂ and the slope 127 and is kept parallel to the plate-like piezoelectric elements 121, 122. I'm leaning.

In this state, when a traveling wave having a phase shifted by π / 2 as described with reference to FIG. 5 is applied to each of the driving members 121 and 122, the moving body 126 is synchronized with both sides of the moving body 126 by the arrows 128 ₁ , or force to move is added to 128 ₂ directions. Therefore, for example, the movement of the moving body 126 in the extending direction (the direction of the arrow 128 ₁ or 128 ₂ ) is performed by moving the slope 127 in the direction of the arrow 129 ₂ against the force of pressing the slope 127 in the direction of the arrow 129 _1. The moving force can be a direction perpendicular to the extending direction.

  In the above-mentioned Patent Document 5, two driving members composed of the plate-like piezoelectric elements 121 and 122 are used, and the driving heads of the respective driving members are arranged on a central plane parallel to the contact surface of the driving head in the moving body 126. On the other hand, a configuration in which the moving body 126 is sandwiched by being disposed at a target position is shown. However, in such a configuration, if at least one end of the moving body 126 is not held in a structure like a bearing, Cannot move in parallel.

However, if a structure such as a bearing is provided, the frictional force increases as a matter of course. On the other hand, in the configuration shown in FIG. 6, the moving body 126 is supported at three points by the drive heads 123 ₁ , 123 ₂ , and the slope 127, and it is not necessary to bring other members into contact with the moving body 126. The force is reduced, and the moving body 126 can be moved with a small force.

  The camera module 1 of the embodiment moves the lens unit 2 in the optical axis direction by the drive mechanism 3 configured according to such a concept. That is, as shown in FIGS. 3, 4A, and 4B, the drive head 310 of the piezoelectric element 31 constituting the drive mechanism 3 of the camera module 1 according to the embodiment is the drive head 320 of the piezoelectric element 32. It is further provided on the slope 22 side. The slope 22 is provided integrally with a bearing portion 21 provided in the lens unit 2, and the bearing portion 21 is further connected to the sensor unit 6 by a spring 42 (see FIGS. 2, 3, and 4B). A pressing force is applied in the direction of leaving.

  On the other hand, the piezoelectric element 32 is a piezoelectric element biasing spring 35 having an elastic force corresponding to the pressing force of the spring 42 and is pressed between the driving heads 310 and 320 because the pressing force in the direction of the interlocking lever 33 is applied. The interlocking lever 33 is supported at three points by the drive heads 310 and 320 and the cam slope 22 and is kept parallel to the piezoelectric elements 31 and 32. Therefore, since the members other than the drive heads 310 and 320 and the cam slope 22 do not contact the interlocking lever 33 as described above, the frictional force is reduced correspondingly, and the interlocking lever 33 can be moved with a small force.

  The piezoelectric element 32 and the piezoelectric element biasing spring 35 are accommodated in the piezoelectric element accommodating portion 43 in FIGS. 2 and 3 while being restricted on both sides in the extending direction. As is apparent from FIG. The element 32 is supported at two points by the piezoelectric element pressing protrusion 351 of the piezoelectric element biasing spring 35 and is pressed toward the interlocking lever 33. One piezoelectric element 31 is accommodated in a piezoelectric element accommodating portion 52 provided inside the cover 5 while being supported at two points by the piezoelectric element supporting protrusions 51 while being restricted on both sides in the extending direction. The spring 42 is held by receiving a pressing force.

  FIG. 7 is a diagram showing a mobile phone 100 as an example of a mobile terminal incorporating the camera module described above. 7A shows a state in which the display unit 101 is closed and the lens unit 2 of the camera module 1 can be seen, and FIG. 7B shows that the display unit 101 can be opened and the operation button 111 provided on the operation unit 110 can be operated. Indicates the state.

  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 is a top view, (B) is a right view, (C) is a front view, (D) is an external perspective view. It is a disassembled perspective view of the camera module which becomes embodiment. It is sectional drawing seen from the arrow direction of the position shown by A-A 'in Drawing 1 (A). 5A is a top view of the lens unit of the camera module and the optical axis direction moving mechanism according to the embodiment, and FIG. 5B is a cross-sectional view of the lens unit viewed from the direction indicated by the arrow BB ′ in FIG. . 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 35 Piezoelectric element pushing spring 351 Piezoelectric element pressing protrusion 4 Drive mechanism frame 41 Guide shaft 42 Spring 43 Piezoelectric element accommodating part 5 Cover 51 Piezoelectric element supporting protrusion 52 Piezoelectric element accommodating part 6 Sensor unit

Claims (8)

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 movable body that is sandwiched between the drive heads of the pair of drive members, extends in the longitudinal direction of the drive member, and moves by receiving a drive force from the drive head;
A cam slope in contact with one end of the moving body;
An elastic member for pressing one drive head of the pair of drive heads toward the moving body;
An elastic member that presses the cam slope toward the moving body,
The one drive head is provided on a side of the movable body in contact with the cam slope, and the other drive head is located on the opposite side of the one drive head across the movable body and the one drive head and the cam slope. Is located at the corresponding position between
The movable body is supported at three points by the pair of drive heads and the cam slope, and the movable body is moved in the longitudinal direction by driving the pair of drive members, so that the cam slope is extended by the movable body. A drive mechanism characterized by moving in a direction perpendicular to the direction.   The drive mechanism according to claim 1, wherein the drive head is configured to be in line contact with the moving body.   The pair of driving members are supported at two points in the vicinity of both ends in the longitudinal direction of the surface opposite to the surface on which the driving head is provided, and the elastic member that presses the one driving head toward the moving body is the one driving member. The drive mechanism according to claim 1, wherein the drive mechanism also serves as a member that supports the member at two points. 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 cam slope fixed to the lens holder and inclined with respect to a surface perpendicular to the optical axis direction;
A drive member formed by laminating piezoelectric elements extending in a plate shape in the thickness direction, and forming the extending direction as a direction substantially orthogonal to the optical axis direction;
A drive head provided at the approximate center in the longitudinal direction of the surface layer of the drive member;
A movable body sandwiched between the drive heads of the pair of drive members and extending in the longitudinal direction of the drive member, one end of which is in contact with the cam slope;
An elastic member for pressing one drive head of the pair of drive heads toward the moving body;
An elastic member that presses the cam slope toward the moving body;
Consists of
The one drive head is provided on a side of the movable body in contact with the cam slope, and the other drive head is located on the opposite side of the one drive head across the movable body and the one drive head and the cam slope. Is located at the corresponding position between
The lens holding body in which the moving body is supported at three points by the pair of driving heads and the cam slope, the moving body is moved in the longitudinal direction by driving the pair of driving members, and the cam slope is fixedly provided. A camera module that is moved in an optical axis direction.   The camera module according to claim 4, wherein the driving head is configured to be in line contact with the moving body.   The pair of driving members are supported at two points in the vicinity of both ends in the longitudinal direction of the surface opposite to the surface on which the driving head is provided, and the elastic member that presses the one driving head toward the moving body is the one driving member. 6. The camera module according to claim 4, wherein the camera module also serves as a member for supporting two members.   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. The camera module according to claim 4, wherein the camera module can be moved in an axial direction. 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 cam slope fixed to the lens holder and having an inclination with respect to a surface perpendicular to the optical axis direction;
A drive member formed by laminating piezoelectric elements extending in a plate shape in the thickness direction, and forming the extending direction as a direction substantially orthogonal to the optical axis direction;
A drive head provided at the approximate center in the longitudinal direction of the surface layer of the drive member;
A movable body sandwiched between the drive heads of the pair of drive members and extending in the longitudinal direction of the drive member, one end of which is in contact with the cam slope;
An elastic member for pressing one drive head of the pair of drive heads toward the moving body;
An elastic member that presses the cam slope toward the moving body,
The one drive head is provided on a side of the movable body in contact with the cam slope, and the other drive head is located on the opposite side of the one drive head across the movable body and the one drive head and the cam slope. Is located at the corresponding position between
The lens holding body in which the moving body is supported at three points by the pair of driving heads and the cam slope, the moving body is moved in the longitudinal direction by driving the pair of driving members, and the cam slope is fixedly provided. A camera module that moves in the direction of the optical axis;
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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