JP4623713B2 - Camera module and portable terminal using the camera module - Google Patents

Description

  The present invention relates to a camera module, and more particularly, to a small and lightweight camera module and a portable terminal equipped with the camera module.

  In general, a camera module has an autofocus (AF) function and a zoom function. For example, a cylindrical cam is disposed on the side surface of an optical lens, and the zoom lens frame and the AF lens frame are arranged by the cylindrical cam. In this example, a cylindrical cam bearing and a lens frame bearing are arranged on the front cover (fixed frame). A solid-state imaging device (CCD) is directly arranged on the housing (case), a cam for detecting the rotation angle is arranged on the side surface of the cylindrical cam, and the rotation angle of the cylindrical cam is detected by a mechanical switch. (See Patent Document 1).

  In addition, there is an AF lead screw and a zoom lead screw arranged at the corner on one side of the case so that the movable lens group of the zoom lens system can be moved along the lead screw. When the photographic optical system is moved along the optical axis by driving the cam, a normal zooming cam area and a macro shooting cam area are continuously formed on the cam, and the cam is driven by a step motor. Here, a so-called tele-macro two-point switching is used to place a cylindrical cam adjacent to the lens frame, and the AF lens frame and zoom lens frame are driven by this cylindrical cam. The motor is disposed on the side surface of the cylindrical cam.

  In addition, a lead screw is integrally provided in the stepping motor, the lead screw is held by the holding member independently together with the stepping motors 22a and 22b, and an attachment member for attaching these holding members to the box 11 which is the lens barrel base body, There is one that is arranged only on one side with respect to the lead screw. Here, the zoom and AF lens frame is driven by two lead screws, and the guide support portion of the lens frame is provided in the housing, and the housing A CCD is arranged at the bottom.

  In addition, it has a focus motor and zoom motor for driving the photographic lens, and a shutter motor and aperture motor for driving the internal mechanism, and a plane perpendicular to the optical axis of the photographic lens is orthogonal to the optical axis and orthogonal to each other. These motors are arranged in the first to fourth quadrants divided by the first axis and the second axis, respectively, so that the center of rotation of the focus motor and the zoom motor passes through the base of the shutter unit. Some have a notch.

  In addition, a movable lens is driven along the optical axis by a screw shaft, and a bearing portion that rotatably holds the screw shaft on the apparatus main body is integrally formed by molding, and the bearing portion has a plurality of slides having different sliding directions. In some cases, the lens frame for zooming and AF is driven by two lead screws, and the bearings of the two lead screws and the two lens frame guide shafts are supported by the upper housing. The CCD is held in the lower housing.

  By the way, in recent camera modules used for mobile terminals such as mobile phones, high-speed, high-precision autofocus (with a high-resolution solid-state image pickup device (CCD)) as with a normal electronic camera (digital camera) ( AF) function and focal length change (zoom) function are required, and further, the miniaturization and weight reduction of the mobile terminal itself inevitably requires a reduction in the size and weight of the camera module.

  In order to change the autofocus and focal length in such a camera module, it is necessary to move the lens group along the optical axis. Therefore, conventionally, an electromagnetic motor or a pulse motor having a rotor is used. The helicoid mechanism, cam ring, lead screw or the like is driven to move the lens group along the optical axis.

  However, the electromagnetic motor using the above rotor requires an electromagnet and a permanent magnet around the rotor, and a cylindrical portion is indispensable even if the axial length is shortened. It becomes a bottleneck in making it.

For this reason, it has been proposed to use a piezo element as a drive source. For example, a piezoelectric element is disposed close to a rotary feed member for feeding a lens holding frame, and the piezoelectric element is used to step into the rotary feed member. Here, the piezoelectric element is arranged close to the circumference of the end of the feed screw for driving the lens frame (see Patent Document 2).

  In addition, two types of piezoelectric elements are integrally attached to a guide member that guides the lens holding frame, and these piezoelectric elements are alternately expanded and contracted to cause an intermittent feed operation to the guide member. Here, the piezoelectric element is arranged at the end of the feed screw for driving the lens holding frame (see Patent Document 3).

  In addition, an electromechanical energy conversion element (piezoelectric element) that vibrates when an electric signal is applied is brought into contact with an output member having a screw portion, and the output member is rotated by vibration of the conversion element. There is one that moves the moving member in the axial direction of the output member along with the rotation of the screw part by bringing the moving member into contact with the screw part, and here, around the cylindrical part at the end of the feed screw A piezoelectric element is disposed (see Patent Document 4).

  In addition, a sleeve portion integral with the lens barrel is slidably fitted to the guide bar, and a vibrator of a linear drive type vibration wave actuator is pressed against the outer peripheral surface of the sleeve portion with a leaf spring, so that the piezoelectric element is predetermined. There is one in which two alternating voltages having a phase difference of 2 are applied, axial thrust is applied to the sleeve portion, and the lens barrel is moved along the optical axis (see Patent Document 5).

  For each moving lens frame, one ceramic vibrator is arranged in either the moving lens frame or the fixed portion (lens barrel) of the lens device, and the ceramic vibrator is not arranged. There is a type in which a ceramic vibrator is pressed against a part of either the moving lens frame or the fixed portion, and the lens is driven by an elliptical motion of the ceramic.

  Further, a lens holding frame is screwed into a threaded portion of a drive shaft provided so as to be rotatable around the shaft, a vibrating body provided with a piezoelectric element is brought into contact with a peripheral surface of the driving shaft, and the drive shaft is vibrated by the vibrating body. In some cases, the lens holding frame is driven to move forward and backward along the axial direction of the drive shaft.

  The drive source using a piezo element (piezoelectric element) is low speed, but has high torque, excellent response and controllability, can be positioned very finely, and has a holding torque (or holding force) when not energized, quietness And has advantages such as being small and light. And as a drive source using a piezo element, for example, it is provided with at least one rectangular piezoelectric plate 10 having a long edge part and a short edge part and first and second faces, Attach the electrode and attach a ceramic spacer to the center of the first edge of the edge, and apply elastic force to the center of the second edge opposite to the first edge to attach the ceramic spacer to the object There is one in which either an alternating current or an asymmetric single-pole pulse voltage is applied to the electrode (see Patent Document 6).

  Further, as a driving source using a piezoelectric element, first and second long sides, first and second short sides, front and back surfaces surrounded by long and short sides, a plurality of electrodes connected to the front surface, and A first piezoelectric plate having a counter electrode connected to the back surface is provided, and is connected to the front and back surfaces surrounded by the first and second long sides, the first and second short sides, the long side and the short side, and the front surface. A second piezoelectric plate having a plurality of electrodes and a counter electrode connected to the back surface, the first spacer being attached to the first long side at one end near the first short side of the first piezoelectric plate, The second spacer is attached to the first long side at one end near the first short side of the second piezoelectric plate and engaged with the surface of the object, and each spacer is pressed against the surface of the object, An excitation voltage is applied to the plurality of electrodes, and the first short side of the first piezoelectric plate is moved to the second pressure. The first short side of the plate is that so as to substantially parallel to and close (see Patent Document 7).

  In addition, it has a piezoelectric plate with a spacer attached to one of the two long edge portions, two short edge portions, and the long edge portion as a driving source using a piezo element, and can rotate around the axis. At least one arm, and the arm is provided with first and second ends provided at both ends thereof spaced apart from the axis, a read / write head attached to the first end of the arm, and a second There is a structure in which a rigid member is provided on the end portion, and a spacer of the piezoelectric plate is elastically biased by the rigid member so that the piezoelectric plate is movable with respect to the axis (see Patent Document 8). .

  Similarly, as a drive source using a piezo element, a plurality of electrodes are provided on one surface of the piezoelectric plate, a counter electrode is provided on the other surface, a head is provided at one end of an arm that can be swung around an axis, There is one in which a rigid body is provided at the other end so that the piezoelectric plate is elastically biased toward the rigid body (see Patent Document 9).

  Further, as a driving source using a piezo element, the piezo element moves in the first direction when a voltage is applied between the first electrode group and the common electrode, and between the second electrode group and the common electrode. When a voltage is applied to the first and second electrode groups, the first electrode group and the second electrode group are connected to a low voltage by a switch so as to selectively move in the first or second direction. (See Patent Document 10).

  In addition, as a driving source using a piezo element, the vibrator has a rectangular parallelepiped shape formed of a plurality of thin layers made of piezoelectric material, and this layer has the same first and second relatively large square mains. The main surface is defined from a long end surface and a short end surface, the layers are stacked and the main surfaces are bonded together, the electrode is on the surface of the layer, and the contact region is one or more of the layers There is one which is arranged on an end face and applies a voltage to an electrode in order to excite vibration in a contact region (see Patent Document 11).

JP 7-63970 A Japanese Patent Laid-Open No. 4-291213 JP-A-4-221910 JP-A-8-47273 JP-A-7-104166 JP-A-7-184382 Japanese Patent No. 2980541 JP 9-37575 A JP 2000-40313 A Special table 2002-529037 gazette Special table 2003-501988 gazette

  By the way, in a camera module used for a portable terminal such as a mobile phone, downsizing is always required. To apply to such a portable terminal, the driving mechanism must be downsized. In a conventional camera module, Even if a piezo element is used, since the lens holding member is moved by the slider, there is a problem that it is difficult to make the lens compact and the configuration becomes complicated.

  In view of the above circumstances, an object of the present invention is to provide a camera module that can be configured to be small and light even if an autofocus (AF) function and a zoom function are incorporated using a piezoelectric element.

In order to solve the above problems, a camera module according to the present invention includes a first lens holding unit that holds at least one optical lens, a second lens holding unit that holds at least one optical lens, A first lead screw that engages with the first lens holding portion to move the first lens holding portion along the optical axis, and is disposed substantially parallel to the optical axis, and the second A second lead screw that engages with the lens holding portion to move the second lens holding portion along the optical axis, and is arranged substantially parallel to the optical axis; and the first lead screw; A first rotor configured to be concentric and substantially cylindrical and having an outer diameter larger than that of the first lead screw and rotating integrally with the first lead screw; and the second lead screw. And concentric It consists of a substantially cylindrical shape, and, the second having a larger outer diameter than the lead screw, the second rotor of the second lead screw and integrally rotated, the first operating portion on the end portion And the first actuating portion abuts the first rotor from the subject side , thereby applying a rotational driving force to the first lead screw when energized and the first lead screw when not energized. wherein a first piezoelectric element for imparting holding torque, provided with a second actuating portion at the end portion, by the actuating portion of said second contact from the imaging side to the second rotor, when energized to And a second piezo element that applies a rotational driving force to the second lead screw and applies a holding torque to the second lead screw when no current is applied .

In the present invention, the first piezo element and the second piezo element each have a substantially longitudinal shape, and the first piezo element and the second piezo element are arranged in the longitudinal direction of the longitudinal shape. It arrange | positions so that it may become substantially parallel to an optical axis. In the present invention, the first rotor is disposed substantially end on the object side of the front Symbol first lead screw, substantially end imaging side of the second rotor before Symbol second lead screws It is arranged in the part.

  In the present invention, the first piezo element applies a rotational driving force to the first lead screw by bringing the first operating portion into contact with a subject side surface of the first rotor, and The second piezo element applies a rotational driving force to the second lead screw by bringing the second operating portion into contact with the imaging-side surface of the second rotor.

  Further, in the present invention, the first lead screw rotates integrally with the first lead screw, and is disposed near the subject side of the first lead screw or near the subject side of the first rotor. The first shaft member having a smaller diameter than the one lead screw and the second lead screw rotate integrally, and in the vicinity of the substantially end portion on the imaging side of the second lead screw or the second rotor. And a second shaft member having a smaller diameter than that of the second lead screw.

  In the present invention, a guide shaft member disposed substantially parallel to the optical axis, a first guide member guided by the guide shaft member disposed in the first lens holding portion, and the second lens holding And a second guide member guided by the guide shaft member disposed in the section.

  In the present invention, at least one optical lens is held, a third lens holding portion that rotatably holds the second lead screw, and the first lead screw is rotatably held. A base portion, the third lens holding portion further holds the first piezo element, and the base portion further holds the second piezo element.

  In the present invention, the third lens holding portion further holds the guide shaft member and rotatably holds the first shaft member, and the base portion further holds the guide shaft member. In addition, the second shaft member is rotatably held, and further includes a substantially cubic case portion including the third lens holding portion and the base portion. The image sensor and a substrate that holds the image sensor provided on the lower surface of the base portion are further included, and the third lens holding portion is disposed on the upper surface of the case portion.

According to the present invention, a first lens holding unit that holds at least one or more optical lenses, a second lens holding unit that holds at least one or more optical lenses, and the first lens holding unit, Engage with the first lens holding portion to be movable along the optical axis, and engage with the first lead screw disposed substantially parallel to the optical axis and the second lens holding portion. The second lens holding portion is configured to be movable along the optical axis, and is configured by a second lead screw disposed substantially parallel to the optical axis, and a substantially cylindrical shape concentric with the first lead screw. And a first rotor having an outer diameter larger than that of the first lead screw and rotating integrally with the first lead screw, and a substantially cylindrical shape concentric with the second lead screw. And the second re- Has a larger outer diameter than the de screw, a second rotor which said second lead screw and integrally rotated, provided with a first operating portion at the end portion, the actuating portion of the first is the first A first piezo element that applies a rotational driving force to the first lead screw when energized and a holding torque to the first lead screw when de-energized by abutting on the rotor of 1 from the subject side; provided with a second actuating portion at the end portion, by the actuating portion of said second contact from the imaging side to the second rotor, as well as imparting a rotational driving force to said second lead screw when energized a camera module and a second piezoelectric element for imparting holding torque to said second lead screw when not energized, and the operation member, a display member, a battery, a communication unit, the camera Joule, wherein the display member, the portable terminal is obtained which; and a housing which is limited to the height of substantially the camera module thickness while accommodating the battery and the communication unit.

  As described above, in the present invention, the first and second piezo elements are provided, and the operating portion of the first piezo element is pressed against one surface of the first rotor so that the first piezo element is along the optical axis. The second piezo element is pressed against one surface of the second rotor so that the second piezo element extends to the opposite side of the first piezo element along the optical axis. The driving mechanism for driving the first and second lens holders can be simplified, and the camera module when the autofocus (AF) function and the zoom function are incorporated can be configured to be small and lightweight.

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

  FIG. 1 is a perspective view showing an example of a camera module according to Embodiment 1 of the present invention with a camera frame (camera housing) omitted, and the illustrated camera module 10 includes a CCD 11, which is a wiring board 11a. Mounted on top. Then, the light received by the light receiving surface of the CCD 11 through the optical lens system 12 is converted into an electric signal by the CCD 11. As shown in the drawing, the camera module 10 has a pair of guide shafts 13 and 14, and the first and second lens holders 15 and 16 are slidably supported on the guide shafts 13 and 14, respectively. The first and second lens holders 15 and 16 are guided by guide shafts 13 and 14 and are movable along the optical axis.

  The first and second lens holders 15 and 16 hold at least one optical lens. Further, a third lens holder 17 having at least one optical lens is disposed on the upper side of the second lens holder 16 (that is, the subject side) (FIG. 1 shows only the optical lens). However, reference numeral 17 denotes a third lens holder for holding the optical lens).

  As shown in the figure, a first lead screw 18 is disposed substantially parallel to the optical axis, and the first lead screw 18 is engaged with the first lens holder 15. When the lead screw 18 is driven to rotate, the first lens holder 15 moves along the optical axis. Similarly, the second lead screw 19 is disposed substantially parallel to the optical axis, and the second lead screw 19 is engaged with the second lens holder 16. When the lead screw 19 is driven to rotate, the second lens holder 16 moves along the optical axis.

  A cylindrical (disc-shaped) first rotor 20 is attached to the upper end (subject side end) of the first lead screw 18 (the first rotor 20 is concentric with the first lead screw 18). The operating portion 21a of the first piezo element 21 is in contact with the upper surface (subject side surface) of the first rotor 20, and the first piezo element 21 operates to The first rotor 20 rotates, whereby the first lead screw 18 rotates, and the first lens holder 15 moves along the optical axis.

  A cylindrical (disc-shaped) second rotor 22 is attached to the lower end (end opposite to the subject side end) of the second lead screw 19 (the second rotor 22 is the second rotor 22). The actuating portion 23a of the second piezo element 23 is in contact with the lower surface of the second rotor 22 (the surface opposite to the object side surface), and is concentric with the lead screw 19. The second rotor 22 is rotated by the operation of the second piezo element 23, whereby the second lead screw 19 is rotated, and the second lens holder 16 is moved along the optical axis.

  As shown in FIG. 1, the total length of the first lead screw 18 and the first piezo element 21 is the total length of the second lead screw 19 and the second piezo element 23. (Ie, the length of the first lead screw 18 + the length of the first piezo element 21 = the length of the second lead screw 19 + the length of the second piezo element 23).

  2 to 4, FIG. 2 is a view of the camera module 10 as viewed from above with the upper body excluding the camera frame, and FIG. 3 is a view of the camera module 10 as viewed from the side. FIG. 4 is a view of FIG. 3 viewed from the side at another angle. Although not shown, the substantially cubic camera frame is formed of, for example, fluorine-containing polycarbonate. The camera frame has a bearing portion (see FIG. 1) for supporting the first lead screw 18 and the second lead screw 19. (Not shown) is formed, and the first lead screw 18 is supported by a bearing portion (not shown) so as to be rotatable between the upper surface and the lower surface of the camera frame. An optical sensor (light emitting element and light receiving element) is attached to the side surface of the camera frame, and the optical sensor detects the reference position of the optical lens system 12 and the amount of movement from the reference position. A third lens holder 17 is attached to the upper surface of the camera frame.

  Although not shown, the first piezo element 21 is urged downward by a coil spring, and the second piezo element 23 is urged upward by a coil spring. As a result, when the first piezo element 21 is excited, high-order bending vibration is generated in the operating portion 21a and a traveling wave is generated. Then, a frictional force is generated between the first rotor 20 and the operating portion 21a to which the operating portion 21a is pressed, and the first rotor 20 is rotationally driven by this frictional force (this principle is explained as an ultrasonic motor). For details, see, for example, the piezoelectric micromotor described in Japanese Patent Laid-Open No. 8-237971).

  A cam body (not shown) is formed on the outer peripheral surface of the first lead screw 18, and similarly, a cam body (not shown) is also formed on the second lead screw 19. As described above, when the first piezo element 21 and the second piezo element 23 are excited, the first rotor 20 and the second rotor 22 are rotationally driven. The rotation directions of the first rotor 20 and the second rotor 22 are changed by changing the direction of the voltage applied to the first piezo element 21 and the second piezo element 23.

  The first and second lead screws 18 and 19 are rotated by the rotation of the first rotor 20 and the second rotor 22, respectively, whereby the first and second lens holders are respectively rotated according to the rotation of each cam body. 15 and 16 move along the optical axis. For example, detection lines 20a extending in the axial direction are formed at predetermined intervals on the outer peripheral surface of the first rotor 20, and the optical sensor irradiates light from the light emitting element to the outer peripheral surface of the first rotor 20. Reflected light from the outer peripheral surface of the first rotor 20 is received by the light receiving element. Since the rotation angle can be detected based on the number of repetitions detected by the detection line 20a, the control unit (not shown) can rotate the first rotor 20 according to the number of repetitions of the received detection line 20a, that is, the first number. The amount of movement of the lens holder 15 is grasped.

  Similarly, the amount of rotation of the second rotor 22 is detected by an optical sensor (not shown) provided corresponding to the second rotor, and the first and second lens holders are detected as described above. Focusing and zooming are performed by relatively driving 15 and 16 along the optical axis to change the relative positions of the first and second lens holders 15 and 16.

  In the camera module 10 shown in the first embodiment, when the first lens holder 15 and the second lens holder 16 are on the wide-angle side, as shown in FIG. When the telephoto (tele) side is separated from the holder 17, the third lens holder 17 is approached as shown in FIG. Then, in correspondence with the lens holder positions shown in FIGS. 5A and 5B, the position of each lens group and the moving range for focusing are shown in FIG. 5C. For focusing, for example, in the case of the wide-angle side in FIG. 5A, the lens holder 15 in FIG. 5C has a range indicated by reference numeral A in FIG. In the case of the (tele) side, the range indicated by symbol B in FIG.

  That is, as shown in FIGS. 6A and 6B, the third lens holder 17 is fixedly arranged, and the first and second lens holders 15 and 16 move to the guide shafts 13 and 14. Supported as possible. When the second lens holder 16 moves to the third lens holder 17 side, a telephoto state is established. Following the movement of the second lens holder 16, the first lens holder 15 also moves to the third lens holder 17 side. Move (refer to FIG. 6A: At this time, during AF, it moves within the scanning range defined by the telephoto). On the other hand, when the second lens holder 16 is returned to the first lens holder 15 side, a wide-angle state is established, and the first lens holder 16 also moves following the movement of the second lens holder 16 (FIG. 6 (b): At this time, during AF, the lens moves within a scan range defined by a wide angle).

  For example, as shown in FIG. 7, the first piezo element 21 described above is formed in a substantially rectangular shape, and a first surface 211 formed in the longitudinal direction and the short direction, and a second side opposite thereto. An electrode (not shown) is provided on the surface 212, and a spacer (actuating portion) 21a that is engaged with an object that is moved relative to the third surface 213 in the lateral direction is provided, and the first surface 211 and the second surface A reciprocating motion is generated in the operating portion 26a by applying a sinusoidal voltage to the electrode provided at 212, thereby realizing a relative movement with respect to the object with which the operating portion 21a is engaged. Thus, since the first piezo element 21 is a friction drive type, the torque is low, but the torque is excellent and the response and controllability are excellent, the positioning is possible, and the holding torque (or holding force) when no current is applied. The second piezo element 23 has the same advantages as the first piezo element 21. In addition, the second piezo element 23 has the same structure as the first piezo element 21.

  With reference to FIGS. 8 and 9, here, a holding member for holding the first and second piezo elements 21 and 23, a mechanism for rotatably supporting the guide shafts 13 and 14 and the lead screws 18 and 19 will be described. To do. Although not shown in FIGS. 1 and 2, the base member 40 is disposed on the substrate 11a, and the third lens holder 17 has a frame body 17b for holding the lens 17a. A first piezo element holding member 41 is held on the frame body 17b, and a second piezo element holding member 42 is held on the base member 40. As shown in FIG. 8, one end (lower end) of the second piezoelectric element holding member 42 is supported by the base member 40 and extends upward in the optical axis direction to the second piezoelectric element holding member 42. The second piezo element holding member 42 has a hollow rectangular parallelepiped shape, and a support protrusion 42a is formed on the inner wall of the second piezo element holding member 42. By this support protrusion 42a, the second piezo element 23 becomes a second piezo element holding member. 42 is supported. The surface of the second piezo element holding member 42 facing the first rotor 22 is opened, and the operating portion 23 a protrudes from the opening surface and is in pressure contact with the lower surface of the first rotor 20.

  The first piezo element holding member 41 is also configured in the same manner as the second piezo element holding member 42, and one end (upper end) of the first piezo element holding member 41 is supported by the frame body 17b. The holding member 41 extends downward in the optical axis direction. The first piezo element 21 is held in the first piezo element holding member 41 (the support protrusion 41a of the first piezo element holding member 41 is shown in FIG. 13), and the operating portion 21a is The upper surface of the first rotor 20 is in pressure contact.

  As shown in FIG. 8, a bearing portion 43 protruding downward is formed on the lower surface of the frame body 17 b, and the upper end of the first lead screw 18 is rotatably supported by the bearing portion 43. On the other hand, at a position facing the bearing portion 43, a bearing portion 44 is defined on the upper surface of the base member 40, and the lower end of the first lead screw 18 is rotatably supported by the bearing portion 44. Similarly, as shown in FIG. 9, a bearing portion 45 protruding upward is formed on the upper surface of the base member 40, and the lower end of the second lead screw 19 is rotatably supported by the bearing portion 45. ing. On the other hand, at a position facing the bearing portion 45, a bearing portion (not shown) is defined on the lower surface of the frame body 17b, and the upper end of the second lead screw 19 is rotatably supported by the bearing portion.

  Furthermore, the upper ends of the guide shafts 13 and 14 are supported by the frame body 17b, and the lower ends of the guide shafts 13 and 14 are supported by the base member 40. Then, the assembled body assembled as described above is housed in the case 46 as shown in FIG.

  Referring to FIG. 11, FIG. 12 is a diagram for explaining the principle of operation of the first piezo element 21. As described above, the first piezo element 21 is formed by the first piezo element support portion 41. The first piezo element 21 is urged toward the first rotor 20 by the first piezo element support portion 41, and the operating portion 21 a of the first piezo element 21 is moved to the first rotor 20. It is pressed against the outer peripheral surface (see FIGS. 11A and 11B). As a result, when the first piezo element 21 is excited, as shown in FIGS. 11C and 11D, the first piezo element 21 performs a bending motion and operates with the first rotor 20 by this bending motion. The first rotor 20 is rotated by the frictional force generated between the portion 21a. Since the first piezo element 21 is bent in a direction intersecting the optical axis, it is desirable to hold the first piezo element 21 at two positions on the side surface.

  As is clear from the above description, the first and second piezo elements 21 and 23 are arranged such that their longitudinal directions are parallel to the optical axis, and the first rotor 20 is formed by the first lead screw 18. The second piezo element 23 is disposed at the object-side end, and the second piezo element 23 is disposed at the image-side end of the second lead screw 29. The first piezo element 21 abuts the operating portion 21 a on the subject-side surface of the first rotor 20 to apply a rotational driving force to the first lead screw 18, and the second piezo element 23. The abutting portion 23 a is brought into contact with the image-forming surface of the second rotor 22 to apply a rotational driving force to the second lead screw 19.

  With reference to FIGS. 12-14, the other example of the camera module 10 by this invention is demonstrated. 12 to 14, the same components as those in FIGS. 8 and 9 are denoted by the same reference numerals, and description thereof is omitted. In the illustrated example, one end (upper end) of a first shaft member 47 having a smaller diameter than that of the first lead screw 18 is rotatably attached to the lower surface of the frame body 17b. The first lead screw 18 is connected to the first rotor 20 disposed at the upper end.

  Similarly, as shown in FIG. 14, one end (lower end) of a second shaft member 48 having a smaller diameter than the second lead screw 19 is rotatably attached to the upper surface of the base member 40. The shaft member 48 is connected to the second rotor 22 disposed at the lower end of the second lead screw 18. That is, in this example, the first lead screw 18 rotates integrally with the first lead screw 18, and is near the subject side end of the first lead screw 18 or the subject side of the first rotor 20. The first shaft member 47 having a smaller diameter is disposed, and is rotated integrally with the second lead screw 19, so that the second lead screw 19 is near the end of the imaging side or the second rotor 22. A second shaft member 48 having a smaller diameter than the second lead screw 19 is disposed on the image forming side. The first and second shaft members 47 and 48 may have the same diameter as the first and second lead screws 18 and 19, but the first and second lead screws 18 and 19 have a smaller diameter than the first and second lead screws 18 and 19. If the second shaft members 47 and 48 are arranged, a space for arranging the first and second piezoelectric elements can be secured, and as a result, the camera module itself can be formed in a small size.

  The above-described camera module is incorporated into a mobile terminal, for example. FIG. 15 is a plan view showing a mobile phone 50 as an example of a mobile terminal in a state (open state) in which an operation unit (operation member) 51 and a display (display member) 52 can be seen. The first case portion 53 on which 51 is mounted and the second case portion 54 on which the display 52 is mounted are connected by a hinge mechanism 55, and the first and second case portions 53 and 54 are arranged around the hinge mechanism 55. Can be rotated. In addition, the 1st and 2nd case parts 53 and 54 comprise a case body.

  The second case 54 incorporates the above-described camera module 56 as indicated by a broken double circle in the figure. When a predetermined button of the operation unit 51 is operated, the camera module 56 takes an image, An image captured by the camera module 56 is displayed on the display 52, for example. Note that the upper side of the camera module 56 shown in FIG. 1 is directed to the outside of the second case portion 54.

  That is, the second case portion 54 has an opening for exposing the optical lens held by the third lens holder 17 of the camera module 56. Although not shown, the first case portion 53 accommodates a battery, a communication portion, and the like. Further, the thickness dimension of the second case portion 54 is substantially regulated by the height of the camera module 56. Yes.

  In this way, the first and second lens holders 15 and 16 are driven along the optical axis using the first and second piezo elements, respectively. Therefore, the first and second lens holders 15 are driven. And 16, that is, the structure of the lens moving mechanism when driving the optical lens system becomes extremely simple, and even if an autofocus (AF) function and a zoom function are incorporated, the camera module can be reduced in size and weight.

  First and second piezoelectric elements are provided, the operating portion of the first piezoelectric element is pressed against one surface of the first rotor, the first piezoelectric element extends along the optical axis, and the second piezoelectric element Since the operating portion of the element is pressed against one surface of the second rotor so that the second piezo element extends along the optical axis to the opposite side of the first piezo element, the first and second lens holders are Even if the drive mechanism to drive can be simplified and the auto focus (AF) function and zoom function are incorporated, the number of parts is reduced and the camera module can be reduced in size and weight, so that it can be applied to a camera module mounted on a portable terminal or the like. .

1 is a perspective view schematically showing an example of a camera module according to Embodiment 1 of the present invention with a camera frame (camera housing) omitted. It is the figure which looked at the camera module by Example 1 of this invention from upper direction. It is the figure which looked at the camera module by Example 1 of this invention from the side. It is a side view which shows the camera module shown in FIG. 3 from another angle. It is a figure for demonstrating the movement of the lens group which comprises the optical system in the camera module by Example 1 of this invention, (a) is a figure which shows the state which has a lens group in the wide angle (wide) side, (b). FIG. 6 is a diagram illustrating a state in which the lens group is on the telephoto (tele) side, and FIG. 5C is a diagram for explaining a moving range of the focusing lens on the telephoto side and the wide angle side. 4A and 4B are diagrams for explaining movement of a lens group constituting an optical system in the camera module according to Embodiment 1 of the present invention, where FIG. 5A is a diagram illustrating a telephoto state, and FIG. It is a perspective view which shows the shape of the piezoelectric element used in Example 1 of this invention. It is a perspective view which shows holding | maintenance of a piezoelectric element, and support of a lead screw and a guide shaft from diagonally upward. It is a side view which shows holding | maintenance of a piezoelectric element, and support of a lead screw and a guide shaft. It is a perspective view which shows a camera module in the state accommodated in the case. It is a figure for demonstrating operation | movement of the piezo element used in Example 1 of this invention, (a) and (b) are figures which show the support of a piezo element, (c) and (d) are the bending | flexion of a piezo element. It is a figure which shows exercise | movement. It is a perspective view which shows the other example of the camera module by this invention from the side. It is a perspective view which shows the camera module shown in FIG. 12 from diagonally downward. It is a side view of the camera module shown in FIG. It is a figure which shows roughly an example of the mobile telephone incorporating the camera module by this invention.

Explanation of symbols

10 Camera module 11 CCD
13, 14 Guide shafts 15, 16, 17 Lens holders 18, 19 Lead screws 20, 22 Rotors 21, 23 Piezo elements

Claims (12)

A first lens holding unit for holding at least one optical lens;
A second lens holding unit for holding at least one optical lens;
A first lead screw that engages with the first lens holding portion to allow the first lens holding portion to move along the optical axis, and is disposed substantially parallel to the optical axis;
A second lead screw that engages with the second lens holding portion to move the second lens holding portion along the optical axis, and is arranged substantially parallel to the optical axis;
A first rotor configured in a substantially cylindrical shape concentric with the first lead screw, having a larger outer diameter than the first lead screw, and rotating integrally with the first lead screw; ,
A second rotor configured in a substantially cylindrical shape concentric with the second lead screw, having a larger outer diameter than the second lead screw, and rotating integrally with the second lead screw; ,
A first actuating part is provided at the end, and the first actuating part comes into contact with the first rotor from the subject side, so that a rotational driving force is applied to the first lead screw during energization and there is nothing. A first piezoelectric element that applies a holding torque to the first lead screw when energized ;
Provided with a second actuating portion at the end portion, by the actuating portion of said second contact from the imaging side to the second rotor, as well as imparting a rotational driving force to said second lead screw when energized And a second piezo element that applies a holding torque to the second lead screw when no power is supplied . Each of the first piezo element and the second piezo element has a substantially longitudinal shape,
2. The camera module according to claim 1, wherein the first piezo element and the second piezo element are arranged so that a length direction of each of the longitudinal shapes is substantially parallel to an optical axis. It said first rotor is disposed substantially end on the object side of the front Symbol first lead screw,
It said second rotor camera module according to claim 1 or 2, wherein arranged in substantially end portion of the imaging side of the front Stories second lead screw. The first piezo element applies a rotational driving force to the first lead screw by bringing the first operating portion into contact with a subject side surface of the first rotor,
The second piezo element applies a rotational driving force to the second lead screw by bringing the second operating portion into contact with the image-side surface of the second rotor. The camera module according to Crab. The first lead screw rotates integrally with the first lead screw, and has a smaller diameter than the first lead screw disposed near the subject end of the first lead screw or on the subject side of the first rotor. A first shaft member of
The second lead screw that rotates integrally with the second lead screw and is arranged in the vicinity of the image forming side of the second lead screw or in the image forming side of the second rotor. The camera module according to claim 1, further comprising a second shaft member having a smaller diameter. A guide shaft member disposed substantially parallel to the optical axis;
A first guide member guided by the guide shaft member disposed in the first lens holding portion;
The camera module according to claim 1, further comprising: a second guide member guided by the guide shaft member disposed in the second lens holding portion. A third lens holding unit for holding at least one optical lens and holding the second lead screw rotatably;
The camera module according to claim 1, further comprising a base portion that rotatably holds the first lead screw. The third lens holding unit further holds the first piezo element,
The camera module according to claim 7, wherein the base portion further holds the second piezo element. The third lens holding unit further holds the guide shaft member and rotatably holds the first shaft member,
The camera module according to claim 8, wherein the base portion further holds the guide shaft member and rotatably holds the second shaft member.   The camera module according to claim 9, further comprising a substantially cubic case portion including the third lens holding portion and the base portion. An image pickup device, and a substrate that holds the image pickup device provided on the lower surface of the base portion,
The camera module according to claim 10, wherein the third lens holding portion is disposed on an upper surface of the case portion. A first lens holding part that holds at least one optical lens, a second lens holding part that holds at least one optical lens, and the first lens holding part engaged with the first lens holding part. The first lens holding portion can be moved along the optical axis, and the first lead screw disposed substantially parallel to the optical axis and the second lens holding portion are engaged with the second lens holding portion. The first lead screw and a second lead screw arranged substantially parallel to the optical axis, and a substantially cylindrical shape concentric with the first lead screw, and the first lead screw A first rotor having an outer diameter larger than that of the first lead screw, the first rotor rotating integrally with the first lead screw, a substantially cylindrical shape concentric with the second lead screw, and the first 2 lead screw Large has an outer diameter, wherein the second rotor to the second lead screw and integrally rotated, provided with a first operating portion at the end portion, the actuating portion of the first said first rotor the by contact from the object side, a first piezoelectric element for imparting holding torque to said first lead screw when not energized with imparting rotational driving force to said first lead screw when energized, the end portion A second actuating part is provided, and the second actuating part comes into contact with the second rotor from the image forming side , thereby applying a rotational driving force to the second lead screw during energization and during no energization. A camera module including a second piezo element for applying a holding torque to the second lead screw ;
An operation member, a display member, a battery, a communication unit,
A portable terminal comprising: a housing that houses the camera module, the display member, the battery, and the communication unit, and that has a thickness dimension substantially limited to a height of the camera module.

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