JP2005070609A - Method for driving lens driving device and lens driving device and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make reduction of electric power consumption possible, to permit the extension of a photographing function and to facilitate movement control of a lens. <P>SOLUTION: The method for driving the lens driving device relates to a lens driving device having a moving object 10 equipped with a lens 14 and a stationary object 24 for holding the moving object 10 movably in the direction of an optical axis 11. The stationary object 24 is equipped with a pair of driving coils 28 and 30 spaced in the optical axis 11 direction. The moving object 10 is equipped with a first magnetic means 16 disposed in a position where its magnetism can act on the pair of driving coils 28 and 30. Further, the stationary object 24 has a second magnetic means 35 disposed in a position where its magnetism can act on the first magnetic means 16. The stationary object moves the first magnetic means 16 while receiving the force opposed in directions from both of the pair of driving coils 28 and 30 and stops the first magnetic means 16 in an intermediate position of the entire moving range by the magnetism effect of the second magnetic means 35. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lens driving device driving method, a lens driving device, and a camera.

  A thin camera mounted on a camera-equipped mobile phone or the like has a shorter lens movement distance for performing focus adjustment and zoom adjustment in shooting than a normal camera. For this reason, as a lens driving device applied to these cameras, a lens driving device that directly magnetically drives the lens is suitable.

  As such a magnetic drive type lens driving device, for example, the following is known. That is, it has a cylindrical lens holder that holds the lens, a ring-shaped rotor magnet attached to the outer periphery of the lens holder, and a drive coil that faces the rotor magnet, and by controlling energization to the drive coil, A configuration has been devised in which a lens holder for holding a lens is directly moved in the optical axis direction without using a conversion mechanism, and the lens holder is magnetically held therein (see Patent Document 1).

  On the other hand, what employs a guide shaft that guides a lens holder holding a lens along the optical axis is known as an example of using a conversion mechanism that converts the rotational force of the motor into a straight motion. (For example, refer to Patent Documents 2 and 3).

  In many cases, a mobile phone equipped with a camera is used to take a picture of a subject that is in the vicinity of the user's face or other hand with the mobile phone in one hand. For this reason, many photographic lens systems used in this type of camera have a close-up photographing function. In the case of a photographing lens system having such a close-up photographing function, the lens position when performing normal photographing differs from the lens position when performing close-up photographing, that is, macro photographing. That is, the lens position during close-up photography is a position that is closer to the subject side by a slightly fixed distance than the lens position during normal photography.

  For this reason, this type of photographic lens system includes a drive source for moving the lens position between the normal photographic position and the macro photographic position, and the drive source is driven by switching the switch. The lens moves between shooting positions. However, in portable devices such as mobile phones, it is difficult to employ a motor as a drive source because of the reduction in size and weight of the device. In addition, a lens driving device of a type in which electromagnetic force is directly used for lens driving and the lens is moved for photographing at only two positions, that is, a magnetic lens driving device as described in Patent Document 1 is advantageous. Become.

JP-A-10-150759 (page 3-5, FIG. 1-3) JP-A-9-106314 (FIG. 1) JP-A-10-142472 (abstract)

  Among conventional lens driving devices described in Patent Document 1, that is, a case in which a case for holding a lens is magnetically driven in the optical axis direction and magnetically held there, the lens is held at a predetermined position for a long time. When trying to hold, it is necessary to energize the drive coil while holding. Therefore, there is a problem that power consumption increases and it is not suitable for mounting on a mobile phone or the like that originally has a limited power battery capacity.

  On the other hand, what is described in Patent Documents 2 and 3 has a complicated mechanism for converting rotational force into linear movement, increases the number of parts, and is mounted on a portable device such as a cellular phone. There is a problem that it is not suitable for. In addition, since the conversion mechanism is arranged on the side of the lens in the radial direction, the length in the radial direction becomes large, which tends to be a problem in terms of miniaturization.

  In addition, when the conventional lens driving device that executes only two-position imaging is incorporated in a camera, the functions are narrowed down and the flexibility is lacking. Also, the obtained image tends to be an image with a low level.

  The present invention has been made to solve the above-described problems, and provides a driving method of a lens driving device that enables low power consumption, expands an imaging function, and facilitates lens movement control. The purpose is to propose. Another object of the present invention is to propose a lens driving device and a camera that are suitable for downsizing and capable of extending the photographing function.

  In order to achieve the above-described object, a driving method for a lens driving device according to the present invention is a driving method for a lens driving device including a moving body including a lens and a fixed body that holds the moving body so as to be movable in the optical axis direction. In the method, the fixed body includes a pair of drive coils spaced apart in the optical axis direction, the moving body includes a first magnetic means disposed at a position capable of magnetically acting with the pair of drive coils, and The fixed body has the first magnetic means and the second magnetic means arranged at a position where the magnetic action can be performed, and receives the force whose directions are opposite from both of the pair of drive coils. One magnetic means is moved and the first magnetic means is stopped at an intermediate position of the entire moving range by the magnetic action of the second magnetic means.

  In the present invention, the first magnetic means disposed at a position capable of magnetic action with the pair of drive coils is provided, so that the structure for stopping is not complicated and the power consumption can be reduced and the size can be reduced. It will be suitable for conversion. In addition, the moving body receives and moves the reciprocal forces from both of the pair of drive coils, for example, repulsive forces, so that the moving body naturally moves to an intermediate position where the received forces are balanced, Movement control is easy. Further, since the stop position can be an intermediate position in the entire movement range, the photographing function can be expanded.

  In addition to the above-described invention, the driving method of the lens driving device according to another invention can appropriately adjust the strength of the force generated from the pair of driving coils, and the first magnetic means can be adjusted to a plurality of intermediate positions in the entire movement range. Stopped in position. When this configuration is adopted, the stop position becomes four or more positions, so that it is possible to further expand the photographing function.

  According to another aspect of the invention, in addition to the driving method of the lens driving device according to the above-described invention, the first magnetic means is disposed so as to overlap the opposing surfaces of the pair of driving coils in the optical axis direction. The magnet is NS magnetized in the direction intersecting the axis. When this mechanism is adopted, the magnets are superposed in the optical axis direction, so that the radial direction can be shortened and the magnetic efficiency is high.

  The lens driving device of the present invention is a lens driving device including a moving body including a lens and a fixed body that is movably held in the optical axis direction. The fixed body is separated in the optical axis direction. A pair of drive coils, and a second magnetic means disposed between the pair of drive coils and arranged to be capable of magnetic action on a first magnetic means provided on the moving body. The first magnetic means is disposed between the pair of drive coils and is arranged so as to be able to act magnetically with the pair of drive coils, and the first magnetic means approaches the first side of the pair of drive coils. It is configured to be able to stop at one position, a second position approaching the other side of the pair of drive coils, and a third position between both positions and approaching the second magnetic means, and from the first position or the second position. The force moved away from each of the pair of drive coils to the third position The force to be close enough large force there is moving by the first magnetic means receives.

  In the present invention, since the lens cannot be stopped continuously but is stopped intermittently, the structure for stopping does not become complicated and is suitable for miniaturization. Further, since the stop position is a position obtained by adding an intermediate position to the two positions, the photographing function can be expanded. In addition, since the moving body is moved by a force that is moved away and becomes larger as it is closer, it becomes easier to obtain a stable balanced position, and guidance control to the intermediate position is facilitated.

  According to a fourth aspect of the present invention, there is provided a camera having the lens driving device according to claim 4 and display means for displaying an image obtained by the lens driving device.

  According to the present invention, the camera can be reduced in size and the camera can have an extended photographing function.

  The driving method of the lens driving device of the present invention can reduce the power consumption, expand the photographing function, and facilitate the lens movement control. In addition, the lens driving device and the camera according to the present invention are suitable for downsizing and have an extended photographing function.

  Embodiments of a lens driving device driving method, a lens driving device, and a camera according to the present invention will be described below with reference to the drawings. In the following, description will be made with a focus on a lens driving device as a main part of the camera. The lens driving device shown in each embodiment has a configuration suitable for mounting as a camera portion of a mobile device such as a mobile phone, but is mounted on another mobile device such as a PDA (Personal Digital Assistance). Anyway.

  The lens driving device according to the first embodiment shown in FIGS. 1 to 4 mainly includes a moving body 10 and a fixed body 24. The moving body 10 has a substantially cylindrical lens barrel 12 in which the optical axis 11 is positioned at the center, and a lens 14 is provided inside the lens barrel 12. The lens 14 is a photographic lens of a camera and is configured by combining a plurality of lenses.

  The upper side of FIG. 1 is a subject side lens 14a, and the lower side is a camera body side lens 14b. An interval holding member 14c is disposed between the lenses 14a and 14b, and a position fixing member 14d is fixed to the lens barrel 12 to position the lenses 14a and 14b further on the back side of the camera body side lens 14b. Yes.

  The outer periphery of the lens barrel 12 is formed with a large diameter on the front side and a small diameter on the rear side, and a step is formed at the boundary. A driving magnet 16 serving as a first magnetic means formed in a ring shape is fitted in the small-diameter portion on the rear side. The drive magnet 16 is integrally fixed to the lens barrel 12 while being in contact with the stepped portion described above. The drive magnet 16 protrudes outward from the outer peripheral surface of the lens barrel 12 as if it is a collar portion of the lens barrel 12.

  At the front end of the lens barrel 12, that is, the end on the subject side, a circular incident window 18 for taking the reflected light from the subject into the lens 14 is formed at the center of the front end surface 20. Although an openable / closable barrier for holding the lens is provided in front of the entrance window 18, the illustration is omitted.

  The lens barrel 12 is inserted into the fixed body 24. The fixed body 24 is also formed in a substantially cylindrical shape. The outer periphery of the rear end portion 22 of the lens barrel 12 is formed on the rear end inner periphery 25, and the optical axis 11 of the lens 14 is guided by the rear end inner periphery 25 of the fixed body 24. It is movably fitted in the direction. The movement limit of the lens barrel 12 toward the heel side, that is, the camera body side, is that the rear end portion of the lens barrel 12 is formed on the protruding edge 27 formed inward at the rear end of the cylindrical portion 26 forming the fixed body 24. The position can be determined by contact. FIG. 1 shows a state in which the lens barrel 12 has moved to the farthest side.

  As shown in FIGS. 2 and 3, the drive magnet 16 that operates integrally with the lens barrel 12 has a ring shape, the portion surrounding the central hole 16a is magnetized to the N pole, and the entire outer peripheral portion is Each of the S poles is single-pole magnetized. This magnetization relationship may be such that NS is reversed. The drive magnet 16 has a slight gap in the inner periphery of the cylindrical portion 26 that is formed on the front side of the inner periphery 25 of the rear end portion of the cylindrical portion 26 and has an inner diameter larger than that of the inner periphery 25 of the rear end portion. It is installed to face each other. The drive magnet 16 is housed so as to be movable relative to the cylindrical portion 26 in the direction of the optical axis 11.

  Further, on the inner periphery of the fixed body 24, a first drive coil 28 wound in a ring shape so as to face the drive magnet 16 is disposed on the heel side of the drive magnet 16. A second drive coil 30 is arranged so as to sandwich the drive magnet 16 with respect to the first drive coil 28.

  A ring-shaped first magnetic piece 32 is fitted on the heel side of the first drive coil 28, and both the first magnetic piece 32 and the first drive coil 28 are fixed to the cylindrical portion 26 of the fixed body 24 by bonding or the like. Yes. As described above, the front end face of the first drive coil 28 and the rear end face of the drive magnet 16 face each other.

  As described above, the second drive coil 30 wound in a ring shape is fitted on the inner periphery of the front end portion of the fixed body 24 at a position in front of the drive magnet 16. Further, a ring-shaped second magnetic piece 34 is fitted on the drive coil 30 and fixed to the cylindrical portion 26 of the fixed body 24 by adhesion or the like. The front end surface of the drive magnet 16 and the rear end surface of the second drive coil 30 face each other. Therefore, the first magnetic piece 32 and the second magnetic piece 34 are arranged on the outer end surfaces of the first drive coil 28 and the second drive coil 30 arranged in the direction of the optical axis 11 with the drive magnet 16 in between, respectively. Will be. The drive magnet 16 is sandwiched between the first and second drive coils 28 and 30 in the direction of the optical axis 11.

The first and second magnetic pieces 32 and 34 are made of a washer-like ferromagnetic material, for example, a steel plate.
The magnetic flux generated from the drive magnet 16 passes through the first drive coil 28 and the first magnetic piece 32 from the center side to the outer peripheral side and returns to the drive magnet 16. Further, the magnetic flux from the drive magnet 16 reaches the drive magnet 16 through the second magnetic piece 34 and the second drive coil 30 from the center side to the outer periphery side, and these members constitute a magnetic circuit. Has been. Therefore, the first and second drive coils 28 and 30 are located in the magnetic field formed by the drive magnet 16.

  The distance between the opposing surfaces of the first and second drive coils 28 and 30 is greater than the thickness of the drive magnet 16 in the direction of the optical axis 11, and is between the drive magnet 16 and the first drive coil 28 or the second drive coil 30. There is a gap in the direction of the optical axis 11, and the drive magnet 16, and thus the barrel 12 integral with the drive magnet 16, can move in the direction of the optical axis 11 within the gap.

  In the lens driving device 1 according to the first embodiment, a ring-shaped third magnetic piece 35 serving as second magnetic means is disposed between the first driving coil 28 and the second driving coil 30. . The third magnetic piece 35 is made of a ferromagnetic material, for example, a steel plate. Due to the presence of the third magnetic piece 35, the drive magnet 16 can be stopped and held during operation. That is, step driving at three positions is possible. As a specific example, in addition to both the normal shooting position and the macro shooting position, a position where the shooting at about 3 m in the middle can be made clean is provided. By using a plurality of third magnetic pieces 35 arranged in the middle instead of one, it is possible to drive four or more steps.

  When the lens barrel 12 advances forward by electromagnetic force, which will be described later, in order to ensure the positioning accuracy of the lens barrel 12, a positioning projection is formed on the surface of the fixed body 24 facing the front end surface 20 of the lens barrel 12. 36 is formed. The positioning protrusions 36 are formed as a plurality of protrusions on the surface of the circular dish-shaped cover 37 constituting the fixed body 24 facing the moving body 10. The cover 37 allows light from the subject to pass to the lens 14 side and prevents external dust and dust from entering the lens 14 side. The cover 37 is fitted to the cylindrical portion 26 of the fixed body 24 and is adhesive. It is fixed to the cylindrical portion 26 by 38 or the like.

  On the heel side along the optical axis 11 of the lens driving device 1, a filter 43 is disposed on the rear end member 42 fixed to the pedestal portion 41, and an image sensor 44 is fixedly disposed on the ridge. The filter 43 is for cutting light of a predetermined wavelength corresponding to the detection wavelength of the image sensor 44. The image sensor 44 is configured by a CMOS (Complementary Metal Oxide Semiconductor) and sends a detection signal to the circuit board 45. An image signal serving as a detection signal is sent to a control unit (configured by a microcomputer or the like) (not shown) via the circuit board 45.

  The outer diameter of the circuit board 45 is made smaller than the diameter of the cylindrical portion 26 that constitutes the fixed body 24, so that it does not protrude outside the cylindrical portion 26. In addition to the CMOS, a CCD, a VMIS, or the like can be used as the image sensor 44.

  In the lens driving device 1, the subject side lens 14 a is an aspherical lens that is integrally molded with the frame portion 46. The camera body side lens 14b is also an aspherical lens molded integrally with the frame 47 by resin. Further, the cover 37 and the cylindrical portion 26 are fixed by an adhesive material 38, and the cylindrical portion 26 and the pedestal portion 41 are fixed by an adhesive material 48.

  Further, there is a gap g1 between the outer periphery of the lens barrel 12 and each inner periphery of the second drive coil 30 and the second magnetic piece 34, and between the outer periphery of the drive magnet 16 and the inner periphery of the tube portion 26. A gap g3 is formed between the outer circumference of the lens barrel 12 and the inner circumferences of the first drive coil 28 and the first magnetic piece 28, respectively. In the lens driving device 1, a relationship of g3> g2 or g3> g1 exists between the gaps g1, g2, and g3. In addition, it is preferable to provide a relationship of g2> g1 between the gaps g1 and g2.

  In addition, the lens driving device 1 is arranged such that the case surface 49a of the mobile phone serving as a portable device and the surface of the cover 37 are on the same plane or substantially the same plane. Further, the image pickup device 44 and the circuit board 45 are arranged between the case back surface 49 b of the mobile phone and the lens 14. For this reason, sufficient space can be taken in the outer peripheral part of the lens drive device 1, and it becomes easy to incorporate this lens drive device 1 in a portable apparatus. Although the case front surface 49a and the case back surface 49b are omitted in other drawings, they are all in the same positional relationship as in FIG.

  Next, a method for assembling the lens driving device 1 according to the first embodiment will be described with reference to FIGS. 1 and 2.

  First, the rear end member 42 having the imaging element 44, the circuit board 45, the filter 43, and the like is fitted and fixed to the pedestal 41. On the other hand, the third magnetic piece 35 is fitted and fixed to the cylindrical portion 26 of the fixed body 24. In this fixing, the rod-shaped third magnetic piece 35 is fitted into the groove portion for the third magnetic piece 35 of the fixed body 24 (the adhesive portion is contained in the groove portion), and the other end after one turn is inserted into the first end. It is performed by making it ring-shaped to contact or be close to. Thereafter, the first magnetic piece 32 is inserted into the cylindrical portion 26 and fixed. Next, the first drive coil 28 is placed and fixed on the first magnetic piece 32. Thereafter, the driving magnet 16 is fixed, and the moving body 10 having the lens 14 therein is incorporated in the cylindrical portion 26.

  Thereafter, the second drive coil 30 is placed and fixed in the cylindrical portion 26, and the second magnetic piece 34 is stacked and fixed on the second drive coil 30. Next, the cover 37 is fitted into the cylindrical portion 26 and temporarily fixed. In this state, the cylindrical portion 26 is inserted into the pedestal portion 41, and the distance between the imaging element 44 and the lens 14 is adjusted so that an appropriate image can be obtained at the normal shooting position. In such a position, the adhesive 48 is inserted between the pedestal portion 41 and the cylindrical portion 26 and both are fixed.

  Next, the cover 37 is moved back and forth in the direction of the optical axis 11, and the cover 37 is fixed at a position where appropriate shooting is possible when the lens 14 is at the macro imaging position. That is, the cover 37 is moved back and forth in the direction of the optical axis 11 with respect to the cylindrical portion 26 so that an appropriate macro image can be obtained at a macro position where the front end surface 20 of the lens barrel 12 is in contact with the positioning protrusion 36. Both are fixed using an adhesive 38 or the like at an appropriate position. As shown in FIG. 2, the positioning protrusions 36 are preferably provided at three positions at intervals of 120 degrees.

  Next, the operation of the lens driving device 1 configured as described above will be described.

  First, as shown in FIG. 1, the drive magnet 16 moves to the side with the lens barrel 12 and is generated between the drive magnet 16 and the first magnetic body 32 even when the drive coils 28 and 30 are not energized. Suppose that it is the state hold | maintained at the position moved by the magnetic attraction force. The position of the lens 14 at this time is a normal shooting position (hereinafter referred to as a normal shooting position). At this time, as shown in FIG. 1, when the first drive coil 28 and the drive magnet 16 collide, either one or both are damaged, and the collision is prevented.

  In the state shown in FIG. 1, when a predetermined macro changeover switch (not shown) is operated, current is supplied in at least one direction of the first and second drive coils 28, 30. Depending on the direction of the magnetic field, the electromagnetic force in the direction of pushing the drive magnet 16 forward by the Fleming's left-hand rule works, and the lens barrel 12 advances forward together with the drive magnet 16. This advance amount is within the above-described gap generated between the drive magnet 16 and the first and second drive coils 28 and 30. The lens 14 moves forward together with the lens barrel 12 to enable a close-up shooting position (hereinafter referred to as a macro shooting position).

  Note that Fleming's left-hand rule shows the relationship of forces acting on an object that is carrying a line current when a line current flows in the magnetic field. In this embodiment, the driving coil 28 , 30 are fixed together, a force acts on the drive magnet 16 as a reaction.

  When the lens barrel 12 advances forward, the front end face 20 collides with the positioning projection 36, thereby preventing the forward advancement. The position of the lens 14 that has advanced to the front is maintained by the magnetic attractive force generated between the drive magnet 16 and the second magnetic body 34 even if the drive coils 28 and 30 are not energized. Also at this time, a slight gap is generated between the second drive coil 30 and the drive magnet 16. This is also for preventing the second drive coil 30 and the drive magnet 16 from colliding and damaging them.

  The electromagnetic force generated during the forward movement is generated in the direction in which the drive magnet 16 is moved forward when the first drive coil 28 is energized, and the drive magnet 16 is activated even when the second drive coil 30 is energized. A direction to move forward is generated. Both the first and second drive coils 28 and 30 may be energized simultaneously, or one of them may be energized.

  To switch from the macro shooting position to the normal shooting position, the changeover switch is switched to the normal shooting position. By this switching, at least one of the first and second drive coils 28 and 30 is energized in the opposite direction. Depending on the direction of the current and the direction of the magnetic field generated by the drive magnet 16, an electromagnetic force acts to pull the drive magnet 16 backward according to Fleming's left-hand rule, and the lens barrel 12 moves backward together with the drive magnet 16 as shown in FIG. The normal shooting position shown in FIG.

  To switch from the normal shooting position to the intermediate shooting position, which is the intermediate position, the changeover switch is switched to the intermediate shooting position. By this switching, a current is passed through the first drive coil 28 so that a force for driving the drive magnet 16 forward is generated by the first drive coil 28. At the same time, a current is passed through the second drive coil 30 so that a force for driving the drive magnet 16 backward (backward side) is generated in the second drive coil 30.

  The drive magnet 16 receives a force that is moved away from both the drive coils 28 and 30. The force in which the directions are opposite is the same as the force itself, and the driving magnet 16 receives the force and moves to a position facing the third magnetic piece 35, where the received force is balanced. Stop at. The force received by the drive magnet 16 is a force that is inversely proportional to the square of the distance. By adjusting the force acting on the drive magnet 16 by providing a difference between the two, it is possible to adjust where the drive magnet 16 is stopped at an intermediate position between the drive coils 28 and 30.

  The drive magnet 16 driven to a position facing the third magnetic piece 35 is held in position by a magnetic action acting between the third magnetic piece 35. That is, after the moving body 10 moves to the intermediate position, no current flows through the first and second drive coils 28 and 30. Even after the intermediate position has been reached, a current during movement may be passed through the first and second drive coils 28, 30 or a current that is a fraction of that after the movement may be passed.

  To switch from the intermediate shooting position to the macro shooting position, the changeover switch is switched from the intermediate shooting position to the macro shooting position. By this switching, an electric current is applied to at least one of the first and second drive coils 28 and 30 so that a force for moving the drive magnet 16 forward acts. As a result, the lens barrel 12 moves forward together with the drive magnet 16 to the macro shooting position.

  Switching from the macro shooting position to the intermediate shooting position is performed by simultaneously supplying current to the first and second drive coils 28 and 30 by switching the changeover switch. This current is applied so that a force that moves the drive magnet 16 away from the drive coils 28 and 30 acts on the drive magnet 16. This state and the subsequent operation are the same as when switching from the normal shooting position to the intermediate shooting position.

  To switch from the intermediate shooting position to the normal shooting position, the changeover switch is switched from the intermediate shooting position to the normal shooting position. As a result of this switching, an electric current is applied to at least one of the first and second drive coils 28 and 30 so that a force for moving the drive magnet 16 backward acts. As a result, the lens barrel 12 moves backward together with the drive magnet 16 to the normal photographing position.

  As described above, the lens driving device 1 can perform photographing at three positions, the normal photographing position, the intermediate photographing position, and the macro photographing position. Moreover, at the three positions, it is not necessary to pass a current through the drive coils 28 and 30, so that low power consumption is achieved.

  In the example of the dimension data of the first embodiment shown in FIG. 1, the outer diameter of the cylindrical portion 26 of the fixed body 24 is 10.5 mm, the height of the cylindrical portion 26 is 5.5 mm, and the lens barrel 12. The moving stroke can be about 0.5 to 1.5 mm. Further, the drive time for supplying current to the first drive coil 28 and the second drive coil 30 for switching between macro photography and normal photography or between both photography and intermediate photography is a minimum of 5 msec.

  In the lens driving device 1 of the first embodiment, it has been described that the cylindrical portion 26 and the cover 37 exist as members constituting the frame of the fixed body 24. The rear end member 42 that holds the image sensor 44 is fixed to the pedestal portion 41 that holds the image pickup element 44 by an adhesive 48 or the like. For this reason, in this embodiment, the rear end member 42 and the base portion 41 also form a part of the fixed body 24.

  In the first embodiment shown in FIG. 1 and the like, the flow of magnetic flux from the drive magnet 16 to the first drive coil 28 and the second drive coil 30 is driven by the first drive coil 28 and the second drive coil 30. What is necessary is just to become a direction component required for the drive of the magnet 16. FIG. Accordingly, the drive magnet 16 may be disposed inside the inner diameter of the drive coil, or may be disposed outside the outer diameter of the drive coil. In order to shorten the radial direction, the drive magnet 16 and the two drive coils 28 and 30 are superposed in the direction of the optical axis 11, that is, a configuration in which at least a part thereof is overlapped in the direction of the optical axis 11. It is preferable to do this.

  Next, the system configuration of the camera 50 including the lens driving device 1 will be described with reference to FIG.

  The camera 50 stores a driver 51 that drives a moving body 10 having a lens 14 to realize a switching operation, an ISP (Image Signal Processor) 52 that processes an image signal obtained from the image sensor 44, and image data. Storage device 53, control logic unit 54, one or more memories 55 for temporarily storing images for electronic processing, display means 56 for displaying optical images and electronic processed electronic images, and each of these members MPU (Micro Processing Unit) 57 as a system controller for controlling the system.

  Here, the camera module corresponding to the lens driving device 1 includes a mechanical part of the lens driving device 1 including the moving body 10 including the lens 14, an imaging element 44, a driver 51, and an ISP 52. The control logic unit 54 and the MPU 57 constitute a control unit. The image sensor 44, the ISP 52, and the control unit constitute an image acquisition unit. The MPU 57 serves as a switching command reading unit that reads a switching command, serves as an operation position confirmation unit that confirms the operation position of the lens 14, and also serves as a current position detection unit that detects the position of the lens 14.

  It should be noted that by providing a sensor for detecting the position of the lens 14, that is, the position of the moving body 10, the sensor may constitute a part of the current position detecting means. The first drive coil 28 or the second drive coil 30 may be used as a sensor. In that case, the first and second drive coils 28 and 30 constitute a part of the current position detecting means.

  Further, the control logic unit 54 may be incorporated in the MPU 57. The display means 56 includes a display element made of liquid crystal and a display driver that drives the display element. The display driver may be arranged in the circuit board 45. The display element may be an LED (Light Emitting Diode), an EL (Electro Luminescent), or other display element. Further, when a plurality of memories 55 are provided as shown in FIG. 4, digital zoom can be performed by using a temporarily stored image to perform smoother electronic processing (digital processing), or images with different resolutions. Can be synthesized.

  Next, a lens driving device 1A according to the second embodiment will be described. In addition, the same code | symbol is attached | subjected to the member same as the member in 1st Embodiment, and the description is abbreviate | omitted or simplified.

  The lens driving device 1A according to the second embodiment shown in FIGS. 5 and 6 mainly includes a moving body 10 and a fixed body 24. The moving body 10 has a lens barrel 12 serving as a substantially cylindrical lens holder in which the optical axis 11 is positioned at the center, and a lens 13 serving as a second group is provided inside the lens barrel 12. Is provided. The lens 13 may be configured by combining a plurality of lenses, or may be configured by a single lens. A lens 15a as the first group is disposed on the upper side (subject side) in FIG. 5, and a lens 15b as the third group is disposed on the lower side (camera body side).

  Here, the first group of lenses 15 a is fixed to the cover 37, and the third group of lenses 15 b is fixed to the fixed body 24. Only the second group of lenses 13 can be moved back and forth in the optical axis direction (see FIG. 6). An openable / closable barrier for protecting the lens is provided in front of the first group of lenses 15a, but the illustration is omitted.

  The lens barrel 12 is inserted into the fixed body 24. The fixed body 24 is also formed in a substantially cylindrical shape. The outer periphery of the rear end portion 22 of the lens barrel 12 is formed on the rear end inner periphery 25, and the optical axis of the lens 13 with the rear end inner periphery 25 of the fixed body 24 as a guide. It is movably fitted in 11 directions. The movement limit of the lens barrel 12 toward the heel side, that is, the camera body side is that the rear end surface of the lens barrel 12 is a concave bottom surface 27 </ b> A formed inward of the rear end of the cylindrical portion 26 that forms the fixed body 24. The position can be determined by abutting on. FIG. 5 shows a state in which the lens barrel 12 has moved to the farthest side.

  The lens 15b of the third group is fixed by an adhesive on the heel side of the fixed body 24 and on the center side of the concave portion surrounding the bottom surface 27A. Further, on the inner periphery of the fixed body 24, a first drive coil 28 wound in a ring shape so as to face the drive magnet 16 is disposed on the heel side of the drive magnet 16, and the first drive coil 28. On the other hand, the second drive coil 30 is arranged so as to sandwich the drive magnet 16.

  The distance between the opposing surfaces of the first and second drive coils 28 and 30 is greater than the thickness of the drive magnet 16 in the direction of the optical axis 11, and is between the drive magnet 16 and the first drive coil 28 or the second drive coil 30. There is a gap in the direction of the optical axis 11, and the drive magnet 16, and thus the barrel 12 integrated with the drive magnet 16, can move in the direction of the optical axis 11 within this gap.

  In the second embodiment, as shown in FIG. 5, the drive magnet 16 and the first magnetic body are moved even if the drive magnet 16 moves to the heel side together with the lens barrel 12 and the drive coils 28 and 30 are not energized. 32 is held at the position moved by the magnetic attraction force generated between the two. The position of the lens 13 at this time is a wide-angle shooting position (hereinafter referred to as a wide-angle position). At this time, as shown in FIG. 5, a slight gap is generated between the first drive coil 28 and the drive magnet 16. This is because when one of the first drive coil 28 and the drive magnet 16 collides, either one or both are damaged, and the collision is prevented.

  In the state shown in FIG. 5, when a predetermined zoom switch (not shown) is operated to the enlargement side, at least one of the first and second drive coils 28 and 30 is energized in a predetermined direction. Depending on the direction and the direction of the magnetic field generated by the drive magnet 16, an electromagnetic force acts to push the drive magnet 16 forward by Fleming's left-hand rule, and the lens barrel 12 advances forward together with the drive magnet 16. This advance amount is within the above-described gap generated between the drive magnet 16 and the first and second drive coils 28 and 30. The lens 13 moves forward together with the lens barrel 12 to become a telephoto shooting position (hereinafter referred to as a telephoto position).

  An enlarged zoomed image may be formed by electronic processing between the wide-angle position and the telephoto position. This enlarged zoomed image has been electronically processed using an optical image taken at a wide-angle position.

  When the lens barrel 12 advances forward, the front end face 20 collides with the positioning projection 36, thereby preventing the forward advancement. The position of the lens 13 that has advanced forward is held by the magnetic attractive force generated between the drive magnet 16 and the second magnetic body 34 even when the drive coils 28 and 30 are not energized. Also at this time, a slight gap is generated between the second drive coil 30 and the drive magnet 16. This is also for preventing the second drive coil 30 and the drive magnet 16 from colliding and damaging them.

  The electromagnetic force generated when moving forward is generated in a direction to move the drive magnet 16 forward when the first drive coil 28 is energized, and the drive magnet 16 is moved forward even when the second drive coil 30 is energized. Generate in the direction to move to the side. Both the first and second drive coils 28 and 30 may be energized simultaneously, or one of them may be energized.

  To switch from the telephoto position to the wide angle position, the zoom switch is switched to the reduction side (wide angle side). By this switching, at least one of the first and second drive coils 28 and 30 is energized in the opposite direction, and the drive magnet 16 is pulled back by Fleming's left-hand rule according to the direction of this current and the direction of the magnetic field generated by the drive magnet 16. The electromagnetic force in the direction works, and the lens barrel 12 moves backward together with the drive magnet 16 to reach the wide angle position shown in FIG. A reduced zoomed image may be formed by electronic processing from the telephoto position to the wide-angle position. The reduced zooming image at this time also uses an optical image at a wide-angle position.

  In the example of the dimension data of the second embodiment shown in FIG. 5, the outer diameter of the cylindrical portion 26 of the fixed body 24 is 9.5 mm, the height of the cylindrical portion 26 is 5.0 mm, and the lens barrel 12. The moving stroke can be about 0.2 to 1.5 mm. The three lenses 13, 15a and 15b are preferably aspherical lenses and resin lenses as shown in FIG. Furthermore, the drive time for supplying current to the first drive coil 28 and the second drive coil 30 for switching between the wide-angle position and the telephoto position is 5 msec at the minimum.

  In this lens driving device 1 </ b> A, the ring-shaped third magnetic piece 35 is disposed between the first driving coil 28 and the second driving coil 30, so that the driving magnet 16 can be stopped and held in the middle of movement. In other words, step driving at three positions is possible, and in addition to both the wide-angle position and the telephoto position, an intermediate position at which macro shooting can be performed is provided. By using a plurality of third magnetic pieces 35 arranged in the middle instead of one, it is possible to drive four or more steps. 5 shows that the third group lens 15b is fixed and cannot move in the direction of the optical axis 11, the lens 15b may be slightly movable in the direction of the optical axis 11.

  Next, how to flow current to the first and second drive coils 28 and 30 of the lens drive devices 1 and 1A according to the first and second embodiments will be described with reference to FIG.

  The arrow shown in FIG. 7 represents the force applied to the drive magnet 16, the up arrow indicates that an electric current is applied so that a force pushing forward is applied, and the down arrow indicates a force pushed back backward. It shows that current is passed as it is applied. In FIG. 7, four types of flowing methods (A), (B), (C), and (D) are shown. Note that the force acting here is inversely proportional to the square of the distance.

  FIG. 7A shows a current of the same capacity to the first and second drive coils 28 and 30 when the moving body 10 is moved to the heel side (first position), that is, the first drive coil 28 side. And a force to move the drive magnet 16 to the heel side is generated. In other words, a current is supplied to the first drive coil 28 so as to generate a force for attracting the drive magnet 16 and to the second drive coil 30 so as to generate a force for moving the drive magnet 16 away. . As a result, the moving body 10 is located at the first position on the heel side from the second position or the intermediate position (the normal photographing position in FIG. 1 and the wide-angle position in FIG. 5).

  When moving the moving body 10 to the front side (second position), that is, to the second drive coil 30 side, the current is applied in the direction opposite to that when the first and second drive coils 28 and 30 are moved to the heel side. Shed. The magnitude of the current is the same as when moving to the heel side. Accordingly, the moving body 10 is positioned at the macro shooting position in the first embodiment and at the telephoto position in the second embodiment. That is, the moving body 10 moves from the first position or the intermediate position to the second position.

When the moving body 10 is moved from the first position or the second position to the intermediate position, a current is applied to the first drive coil 28 so that a force for moving the drive magnet 16 away from the first drive coil 28, and the drive magnet 16 is also supplied to the second drive coil 30. An electric current is passed so that a force to keep the The intermediate position is at a position that is substantially in the middle of the entire movement range of the drive magnet 16, and corresponds to a position at which the force to be moved away is substantially balanced. If the moving body 10 approaches the one drive coil side with momentum, it receives a large repulsive force and is pushed back. For this reason, it becomes easy to stop at an equilibrium point.

  FIG. 7B shows that the current flows only to the second drive coil 30 when moving to the first position, and the current flows only to the first drive coil 28 when moving to the second position. is there. Driving to the intermediate position is the same as in FIG. In FIG. 7C, a current is supplied only to the first drive coil 28 when moving to the first position, and a current is supplied only to the second drive coil 30 when moving to the second position. The movement to the intermediate position is the same as in FIGS. 7 (D) changes the magnitude of the current to be passed. When moving to the first position, the current passed through the second drive coil 30 is double the current to the first drive coil 28. At the time of movement to the second position, the current flowing through the first drive coil 28 is set to be twice the current supplied to the second drive coil 30. When moving to the intermediate position, a double current is supplied to both the first and second drive coils 28 and 30.

  The manner of current flow to the drive coils 28 and 30 is not limited to the four types shown in FIGS. 7 (A), (B), (C), and (D). For example, in FIG. 7, when driving to the intermediate position, a force that moves away from the drive magnet 16 is applied, but an attractive force may be applied. Further, any of the above-described four types of methods may be mixed.

  Further, in the above-described embodiment, a current is supplied at the time of movement and no current is supplied at the stop position. However, a current that is a fraction of that at the stop position is supplied to hold the position. good. In particular, since it is difficult to increase the position holding force at the intermediate position, the current may be kept flowing slightly at the intermediate position. Further, in order to suppress the play due to the vibration at the moment when the shutter is pressed at the time of shooting at the intermediate position, only when the shutter is pressed, a current is passed through each of the drive coils 28 and 30 so that the force to move the drive magnet 16 works. Anyway. That is, a current similar to the current that flows when moving to the intermediate position in FIG. Further, when photographing at the first position or the second position, for the same purpose, a current is applied to one or both of the drive coils 28 and 30, and the moving body 10 is pressed against the first position or the second position. It is also good.

  Each embodiment of the present invention described above is a preferred example of the present invention, but various modifications can be made without departing from the gist of the present invention. For example, although the cylindrical lens barrel 12 is shown as the lens holder, the lens holder may not be separated from the lens, and the lens holder may be provided integrally with the lens using a resin material that is the same material as the lens. .

  In addition, the first and second drive coils 28 and 30 serving as driving means are provided so as to surround the lens barrel 12, but conversely, a lens holder may be arranged so as to surround the driving means. good. Further, although the drive magnet 16 is NS magnetized in the radial direction, it may be NS magnetized in the direction of the optical axis 11.

  Further, as in the first modification shown in FIG. 8, a plurality of ring-shaped midway stopping magnetic bodies 61 (corresponding to the third magnetic pieces 35) serving as the second magnetic means may be provided. . A steel plate or a magnet can be used as the midway stopping magnetic body 61. In FIGS. 8 to 16, only the right half of the optical axis 11 of the main component is shown for easy understanding.

  Further, as in the second modified example shown in FIG. 9, the midway stopping magnetic body 62 that stops at the intermediate position may be configured by adding a coil 64 to the magnetic body 63. If it carries out like this, the attraction | suction force can be strengthened with the coil 64, and the play in the stop position on the way can be suppressed. In this case, the combined configuration of the coil 64 and the magnetic body 63 may be a ring type or a plunger type. In the case of a ring type, each member has a donut shape surrounding the optical axis 11 and is laminated. In the case of the plunger type, the coil 64 is wound around each of the rod-like magnetic bodies 63, and at least two or more, preferably four or more, are installed around the optical axis 11 at equal intervals. As the magnetic body 63 of the midway stop magnetic body 62, a ferromagnetic material such as a steel plate or a magnet is adopted. Further, a plurality of midway stop magnetic bodies 62 in FIG. 9 may be provided as in the third modification shown in FIG.

  Furthermore, as in the fourth modified example shown in FIG. 11, a coil 65 may be provided instead of the magnetic piece as the second magnetic means for stopping halfway. In the case of the coil 65, the drive magnet 16 is stopped at an intermediate position between the drive coil 28 and the coil 65 by the repulsive magnetic field of the coil 65 and the repulsive magnetic field of the drive coil 28, or by the repulsive magnetic field of the coil 65 and the repulsive magnetic field of the drive coil 30. The drive magnet 16 can be stopped at an intermediate position between the drive coil 30 and the coil 65. Furthermore, a plurality of coils 65 may be provided as in the fifth modification shown in FIG. If it does in this way, it can stop also in the middle position of each coil 65. In the case of the coil 65, in order to continue the stop at the stop position, it is necessary to keep the current flowing through the coil 65.

  In addition, as in the sixth modification shown in FIG. 13, the stop position of the drive magnet 16 can be set in multiple stages by supplying a microstep current to the drive coils 28 and 30. In the example shown in FIG. 13, in addition to the two positions of the first position and the second position, it is possible to stop at a total of five positions of three intermediate positions. If the current step is made finer, it is possible to stop at 6 positions or more. Stop position detection in this example is performed by sending small high-frequency signals to the drive coils 28 and 30, exciting them, and detecting changes in inductance when the drive magnet 16 moves. Microstep current control can also be applied to the examples shown in FIGS.

  The drive magnet 16 described above is NS magnetized in the radial direction, but NS magnetized in the direction of the optical axis 11 (axial direction) is also applicable to the first and second embodiments and FIGS. 8 to 13. It can be applied to the modified example. When NS is magnetized in the direction of the optical axis 11, it is preferable in terms of magnetic efficiency that the drive magnet 16 is slightly shifted from the position where the drive magnets 28 and 30 overlap in the direction of the optical axis 11. good.

  Further, a coil 71 with a magnetic material may be used instead of the drive magnet 16 as in the seventh modification shown in FIG. The coil 71 with a magnetic body is composed of a magnetic body 72 and a coil 73. As shown in FIG. 9, this configuration can be a ring type or a plunger type. The configuration employing the magnetic body-equipped coil 71 can be applied (applied) to the modified examples shown in FIGS. Further, a coil 75 may be used instead of the drive magnet 16 as in the eighth modification shown in FIG. This case can also be applied to the changes shown in FIGS. In the example shown in FIGS. 14 and 15, a current is passed through the coil 73 and the coil 75 in order to maintain all positions. However, it is possible to prevent the current from flowing in the position holding at the first position and the second position, and in order to do so, the first and second magnetic pieces 32 and 34 can be handled as magnets.

  Further, a magnetic piece 81 may be used instead of the drive magnet 16 as in the ninth modification shown in FIG. In this case, the second magnetic means may be a magnet 82, a magnetic body 62 for stopping halfway in which a coil 64 is added to a magnetic body 63 as shown in FIG. 9, or a coil 65 as shown in FIG. . Thus, the case of the magnetic piece 81 can also be applied to the modified examples of FIGS. 8 to 13. In the example shown in FIG. 16, in order to hold the position of the magnetic piece 81, it is not the first magnetic piece 32 but the first magnet 83 that makes contact with the drive coil 28, and makes contact with the drive coil 30. Is not the second magnetic piece 34 but the second magnet 84. Both the magnets 83 and 84 function as position holding of the magnetic piece 81.

  The configuration of the camera 50 may be a camera 50A as shown in FIG. In the camera 50A, the memory 55 is arranged on the camera module side, thereby speeding up image processing by the ISP 52 and avoiding interference with system control by the MPU 57.

  Further, the present invention is applicable to all the lenses that need to switch the positions of the lens 14 and the lens 13 to three or more positions. Specifically, in addition to the case of the above-described two embodiments, as a collapsible mechanism of a collapsible camera that houses a lens barrel in a main body of a camera or a portable device when not in use, or a plurality of focal lengths. The present invention can also be applied to a focal length switching mechanism of a camera that can be switched to a position.

  The lens 14 has two lenses 14a and 14b. However, the lens 14 may be a single lens or a combination of three or more lenses. In addition, although the lenses 14a and 14b and the lens 13 are aspherical lenses, they may be spherical glass lenses or aspherical glass lenses.

  In addition, although an example in which each of the moving body 10 and the fixed body 24 is one is shown, the moving body 10 and the fixed body 24 may be arranged so as to overlap two or three or more in the direction of the optical axis 11. Further, the number of the fixed body 24 may be one, and a plurality of sets of the moving body 10, the fixed body side drive coil, and the like may be provided.

  Further, in each of the above-described embodiments and modifications, the example in which the lens driving device 1 or 1A is incorporated as the mechanism of the camera portion of the camera-equipped mobile phone is shown. However, these lens driving device and thin camera are mobile computers. It can be used for other portable devices such as PDAs, or can be incorporated into other camera devices such as surveillance cameras and medical cameras, and electronic devices such as automobiles and televisions.

  The present invention can be applied to a camera device. Further, the present invention can be applied to a mobile device such as a mobile phone having a camera function. Furthermore, any electronic device having a lens position switching mechanism can be incorporated into all electronic devices.

It is sectional drawing which shows the lens drive device which concerns on the 1st Embodiment of this invention. It is a disassembled perspective view of the lens drive device of FIG. It is a top view of the drive magnet used with the lens drive device of FIG. It is a block diagram which shows the system configuration | structure of the camera containing the lens drive device of FIG. It is sectional drawing which shows the lens drive device which concerns on the 2nd Embodiment of this invention. It is a figure explaining the movement of the 2nd group lens in the lens drive device of FIG. It is a figure for demonstrating the flow method of the electric current sent through the 1st, 2nd drive coil of the lens drive device of this invention, (A) (B) (C) (D) is a figure explaining a different flow method. is there. It is a figure which shows the 1st modification of the lens drive device of this invention. It is a figure which shows the 2nd modification of the lens drive device of this invention. It is a figure which shows the 3rd modification of the lens drive device of this invention. It is a figure which shows the 4th modification of the lens drive device of this invention. It is a figure which shows the 5th modification of the lens drive device of this invention. It is a figure which shows the 6th modification of the lens drive device of this invention. It is a figure which shows the 7th modification of the lens drive device of this invention. It is a figure which shows the 8th modification of the lens drive device of this invention. It is a figure which shows the 9th modification of the lens drive device of this invention. It is a figure which shows the other example of the camera of this invention, and is a block diagram which shows the system configuration | structure of the camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A Lens drive device 10 Moving body 11 Optical axis 12 Lens barrel (lens holder)
13 Lens (second lens group)
14 lens 14a subject side lens 14b camera body side lens 15a first lens group 15b third lens group 16 driving magnet (first magnetic means)
18 entrance window 20 front end face 24 fixed body 26 cylindrical portion 28 first drive coil 30 second drive coil 32 first magnetic piece 34 second magnetic piece 35 third magnetic piece (second magnetic means)
36 Positioning projection 37 Cover 41 Base part 42 Rear end member 43 Filter 44 Imaging element 45 Circuit board 50, 50A Camera 51 Driver 52 ISP
53 Storage Device 54 Control Logic 55 Memory 56 Display Unit 57 MPU

Claims (5)

In a driving method of a lens driving device having a moving body including a lens and a fixed body that holds the moving body in an optical axis direction,
The fixed body includes a pair of drive coils spaced apart in the optical axis direction, the moving body includes a first magnetic means disposed at a position capable of magnetically acting with the pair of drive coils, and The fixed body has second magnetic means disposed at a position capable of magnetically acting with the first magnetic means,
The first magnetic means is moved while receiving a force in opposite directions from both of the pair of drive coils, and the first magnetic means is moved entirely by the magnetic action of the second magnetic means. A driving method of a lens driving device, wherein the driving method is stopped at an intermediate position of the range.   2. The lens driving device according to claim 1, wherein intensity of force generated from the pair of driving coils can be adjusted as appropriate, and the first magnetic means is stopped at a plurality of intermediate positions in the entire movement range. Driving method.   The first magnetic means is a magnet which is arranged so as to overlap the opposing surfaces of the pair of drive coils in the optical axis direction and is NS magnetized in a direction crossing the optical axis. The driving method of the lens driving device according to claim 1, wherein: In a lens driving device having a moving body provided with a lens, and a fixed body that is movably held in the optical axis direction.
The fixed body is disposed between a pair of drive coils spaced apart in the optical axis direction and a first magnetic means provided on the movable body so as to be magnetically operable, and disposed between the pair of drive coils. A second magnetic means arranged,
The first magnetic means is disposed between the pair of drive coils and is disposed so as to be magnetically operable with the pair of drive coils.
The first magnetic means is located between a first position approaching one side of the pair of drive coils, a second position approaching the other side of the pair of drive coils, and the second position. Configured to be able to stop at a third position approaching the magnetic means,
From the first position or the second position to the third position, the first magnetic means applies a force that is both a force away from each of the pair of drive coils, and becomes a larger force as it is closer. A lens driving device characterized by moving by receiving. A lens driving device according to claim 4;
Display means for displaying an image obtained by the lens driving device;
A camera characterized by comprising:

Images