JP2006242994A - Lens driving unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving unit for limiting the size in an optical axis direction to the necessary minimum even when adding an accessory unit. <P>SOLUTION: The accessory unit 8 uses a rectangular frame-like laminated core body in order to compose stators 61 and 71 of a shutter plate drive mechanism 60 and a filter plate drive mechanism 70. Since a shutter plate 81 and a dimmer filter 86 are arranged to an object side from the laminated core body, a space 80 is formed in the center in the side of the imaging element 30 of the accessory unit 8. Thus, when a moving lens body 10 is moved to a point blank range position, an edge 15 of a small diameter enters the inside of the space 80 of the accessory unit 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens driving device used for a digital camera or the like.

  An imaging apparatus mounted on a portable device such as a digital camera includes a moving lens body including a lens and a lens driving mechanism for linearly magnetically driving the moving lens body along the optical axis of the lens. A lens driving device is used (see, for example, Patent Document 1).

Further, a lens driving device has been devised in which the rotor is rotationally driven by a stator, the rotational operation is converted into a linear motion, and the moving lens body is linearly magnetically driven along the optical axis of the lens.
JP-A-10-150759

  In such a lens driving device, for example, if an accessory unit such as a shutter mechanism is mounted, camera shake when attempting to capture an image with a digital camera can be prevented. In addition, if an accessory unit such as an aperture mechanism is mounted, the function can be enhanced such that a high-quality image can be taken even when sunlight is strong.

  However, when such an accessory unit is added to the subject side, it is necessary to avoid interference between the movable lens body and the accessory unit when the movable lens body is driven to a close distance position on the subject side. If the accessory unit is disposed on the side opposite to the subject side (image sensor side), it is necessary to avoid interference between the lens unit and the accessory unit when the movable lens body is driven to an infinite position on the image sensor side. . Therefore, when an accessory unit is added, the dimension of the lens drive device in the optical axis direction is only the dimension corresponding to the sum of the thickness dimension of the accessory unit and the dimension to avoid interference between the accessory unit and the moving lens body. There is a problem that the size is increased.

  In view of the above problems, an object of the present invention is to provide a lens driving device that can keep the dimension in the optical axis direction to the minimum necessary dimension even when an accessory unit is added.

  In order to solve the above problems, in the present invention, in a lens driving device including a moving lens body having a lens and a lens driving mechanism for reciprocating the moving lens body along the optical axis of the lens. The object side with respect to the moving lens body includes a plate-like optical member and an optical member driving mechanism for driving the optical member between a position where the optical member appears on the optical path and a position where the optical member is retracted from the optical path. An accessory unit is arranged, and the accessory unit has a space in which the subject side end portion of the movable lens body enters when the movable lens body moves to the closest distance side on the subject side. .

  In the present invention, when the moving lens body is moved to the closest distance position, the distal end portion of the moving lens body enters the space of the attached unit. Therefore, even when the attached unit is arranged on the subject side with respect to the moving lens body, the lens The dimension of the driving device in the optical axis direction can be short. In addition, since the accessory unit is arranged on the subject side having a narrow optical path with respect to the moving lens body, a small optical member can be used as compared with the case where the accessory unit is arranged on the imaging element side having a wide optical path. Suitable for miniaturization of lens driving devices.

  In the present invention, the optical member driving mechanism includes a laminated core, a coil wound around the laminated core, and a rotor magnet rotated by the coil, and the optical member is driven by the rotation of the rotor magnet. Preferably, the optical member is disposed closer to the subject side than the laminated core. If comprised in this way, since the thickness of a lamination | stacking core can be utilized effectively as a space in which a moving lens body enters, the dimension in the optical axis direction of a lens drive device can be shortened.

  In the present invention, the accessory unit includes, for example, at least a shutter plate, a diaphragm plate, a color conversion plate, a neutral density filter plate, an infrared filter plate (infrared cut filter plate or infrared transmission filter), and an ultraviolet filter plate as the optical member. One optical member selected from (ultraviolet cut filter plate or ultraviolet transmission filter) is provided.

  In the present invention, the accessory unit includes at least a shutter plate, a diaphragm plate, a color conversion plate, a neutral density filter plate, an infrared filter plate (infrared cut filter plate or infrared transmission filter), and an ultraviolet filter plate (ultraviolet light) as the optical member. There are cases where two optical members selected from a cut filter plate or an ultraviolet transmission filter) are provided, and in this case, as the optical member driving mechanism, a first optical member that drives one of the two optical members is used. One optical member driving mechanism and a second optical component driving mechanism for driving the other optical member are provided.

  Also in this case, the first optical component driving mechanism includes a first stator including a first laminated core, a first coil wound around a part of the first laminated core, and the first stator. A first rotor magnet that is rotationally driven by the stator of the first rotor, and is configured to drive the one optical component by the rotation of the first rotor magnet. The second optical component drive mechanism includes: And a second stator having a second coil wound around a part of the second laminated core, and a second rotor magnet driven to rotate by the second stator. The other optical component is driven by the rotation of the second rotor magnet, and the first laminated core and the second core are constituted as an integral laminated core body, Any of the optical components and the other optical components are preferably arranged on the object side of the laminated core member. If comprised in this way, since the thickness of a lamination | stacking core can be utilized effectively as a space in which a moving lens body enters, the dimension in the optical axis direction of a lens drive device can be shortened.

  In the present invention, when the moving lens body is moved to the closest distance position, the distal end portion of the moving lens body enters the space of the attached unit. Therefore, even when the attached unit is arranged on the subject side with respect to the moving lens body, the lens The dimension of the driving device in the optical axis direction can be short. In addition, since the accessory unit is arranged on the subject side where the optical path is narrow with respect to the moving lens body, a smaller optical member can be used compared to the case where the accessory unit is arranged on the imaging element side where the optical path is wide. Suitable for downsizing of lens driving device.

  A lens driving device to which the present invention is applied will be described below with reference to the drawings.

(overall structure)
FIG. 1 is a cross-sectional view of a main part of a lens driving device to which the present invention is applied. In FIG. 1, the lens driving device 1 of the present embodiment is such that a thin camera such as a digital camera or a camera-equipped mobile phone moves three lenses 16, 17, 18 along the optical axis L toward the subject (object side). The lens driving device main body 2 is generally composed of three lenses 16, 17, 18 and a fixed stop, and is moved in both directions in the B direction approaching the direction opposite to the subject (image side). The moving lens body 10 that integrally holds 19 on the cylindrical lens holder 11, the lens driving mechanism 5 that moves the moving lens body 10 along the optical axis L, the lens driving mechanism 5, and the moving lens body 10 include And a fixed member 20 mounted thereon. In the present embodiment, the fixing member 20 includes a base 21 that holds the image sensor 30 on the image side, and a case 22 that is positioned on the subject side. The base 21 and the case 22 include screws (not shown) or an adhesive. Etc.

(Configuration of the lens driving mechanism 5)
The lens driving mechanism 5 has a stepping motor structure including a stator 50 and a rotating body 40. The stator 50 includes two annular drive coils 55, and each of the two drive coils 55 is sandwiched between two annular yokes 51. In this state, the pole teeth of the two yokes 51 are alternately arranged in the circumferential direction on both the lower stage side and the upper stage side of the stator 50. Note that a total of four coil terminal wires are drawn from the two drive coils 55, and each of these coil terminal wires is connected to a terminal 81.

  In the lens driving mechanism 5 of the present embodiment, a cylindrical rotating body 40 is coaxially disposed between the moving lens body 10 and the inner side of the cylindrical stator 50. The rotating body 40 has two cylindrical shapes. Drive magnet 41 and cylindrical resin sleeve 42. On the outer peripheral surface of the drive magnet 41, S poles and N poles are alternately arranged in the circumferential direction, and a sleeve 42 is bonded and fixed inside thereof.

  The sleeve 42 is rotatable between the cover 22 and the base 21 around the optical axis L in a state where movement in the optical axis direction is prevented by the thrust bearing 23 or the like. Accordingly, when power is supplied to the two drive coils 55, the rotating body 40 including the drive magnet 41 and the sleeve 42 rotates around the optical axis L.

  Here, on the inner peripheral surface of the sleeve 42, there is a female screw 43 as a driving force transmitting portion that transmits the rotational force of the driving magnet 41 to the moving lens body 10 and moves the moving lens body 10 along the optical axis L. Is formed.

  In the lens driving device 1 of the present embodiment, the moving lens body 10 is coaxially disposed inside the sleeve 42. In the moving lens body 10, a male screw 14 is formed on the outer peripheral surface of the lens holder 11. The moving lens body 10 engages the female screw 43 with the male screw 14, so that the optical axis is It is supported so as to be rotatable around L and movable along the optical axis L. The female screw 43 of the sleeve 42 and the male screw 72 of the moving lens body 10 constitute a transmission mechanism for moving the moving lens body 10 along the optical axis L by the rotation of the drive magnet 41. In the present embodiment, although not shown, one of the case 22 and the rotating body 40 has a plurality of protrusions protruding in the direction of the optical axis L, while the other side has protrusions. A recessed portion to be fitted is formed, and these projections and the recessed portion prevent the moving lens body 10 from rotating when the rotational force of the sleeve 42 is transmitted to the moving lens body 10 via the male screw 14 and the female screw 43. A rotation prevention mechanism is configured. A spring 59 for preventing backlash between the male screw 14 and the female screw 43 is disposed between the movable lens body 10 and the case 22.

  In the lens driving device 1 configured as described above, when the driving coil 55 is supplied with power, the rotating body 40 rotates around the optical axis L, and the rotation is a linear motion that moves along the optical axis by the male screw 14 and the female screw 43. The moving lens body 10 is moved along the optical axis L, and an autofocus operation is performed. FIG. 1 shows a state in which the moving lens body 10 has moved to the closest distance position on the subject side by the one-dot chain line L1, and the moving lens body 10 has the closest position at infinity on the image sensor 30 side by the two-dot chain line L2. It shows how it moved. As can be seen from FIG. 1, the small-diameter end 15 on the subject side of the moving lens body 10 protrudes from the upper surface of the case 22 in a state where the moving lens body 10 has moved to the closest distance position.

(Composition of attached unit)
2, 3, and 4 are a plan view when the accessory unit used in the lens driving device of the present embodiment is viewed from the subject side, a perspective view when the accessory unit is viewed from the subject side, and the accessory unit as an image sensor. It is a perspective view when seen from the side.

  As shown in FIGS. 1 to 4, in the lens driving device 1 of the present embodiment, a shutter plate 81 (on the subject side with respect to the lens driving device main body 2 and the case 22) with respect to the lens moving body 10. Attached unit 8 having a plate-like optical member) and a neutral density filter plate 86 (plate-like optical member) is laminated. In this attached unit 8, an opening 260 for securing an optical path is provided on the subject side. A formed cover 26 is arranged. Here, the shutter plate 81 is composed of one flat plate, and the neutral density filter plate 86 has a structure in which one flat plate is bent at 90 ° at two locations.

  In the attached unit 8, the shutter plate 81 is rotated with respect to the shutter plate 81 about the axis L6 parallel to the optical axis L, and the position where the shutter plate 81 appears in the optical path and the optical path. A shutter plate drive mechanism 60 (first optical member drive mechanism) that drives to the retracted position is configured. The shutter plate driving mechanism 60 includes a stator 61 having a core plate 91 and a coil 82 wound around the core plate 91, and a rotor magnet 84 that is rotationally driven by the stator 61. The rotor magnet 84 rotates. It is fixed to the shaft 83. Here, the shutter plate 81 is disposed closer to the subject side than the shutter plate driving mechanism 60. The rotor magnet 84 has an N pole and an S pole formed in the circumferential direction.

  Further, in the accessory unit 8, with respect to the neutral density filter plate 86, the rotational axis 88 to which the neutral density filter plate 86 is connected is rotated around an axis L 7 parallel to the optical axis L, thereby reducing the neutral density filter plate 86. A filter plate driving mechanism 70 (second optical member driving mechanism) is configured to drive to a position that appears in the optical path and a position that retreats from the optical path. The filter plate drive mechanism 70 includes a stator 71 having a core plate 92 and a coil 87 wound around the core plate 92, and a rotor magnet 89 that is rotationally driven by the stator 71. The rotor magnet 89 rotates. It is fixed to the shaft 88. Here, the neutral density filter plate 86 is disposed closer to the subject than the filter plate driving mechanism 70. The rotor magnet 89 has an N pole and an S pole formed in the circumferential direction.

  In the shutter plate driving mechanism 60 and the filter plate driving mechanism 70 as described above, in this embodiment, five core plates 95, 96, 97, 99 are disposed on the upper layer side of the ground plate 90 disposed in a flat state on the upper surface of the case 22. , 99 are used. In this laminated core body 94, the core plates 95, 96, 97, 99, 99 are each divided in a predetermined pattern. Further, the base plate 90 and the five core plates 95, 96, 97, 99, 99 are connected by four bolts 71, 72, 73, 74 made of a magnetic material as shown in FIGS. Yes.

  Further, in this embodiment, in the shutter plate driving mechanism 60, a part of the third core plate 97 from the top of the laminated core body 94 is used as the core plate 91 around which the coil 82 is wound, and the magnetic path indicated by the arrow L60 is provided. It is configured. Also in the filter plate driving mechanism 70, a part of the third core plate 97 from the top of the laminated core body 94 is used as the core plate 92 around which the coil 87 is wound, and the magnetic path indicated by the arrow 70 is configured. .

(Main effects of this form)
5A, 5B, and 5C are explanatory diagrams for explaining the effect of the present embodiment.

  As described above, in the accessory unit 8 of this embodiment, the stator 61 and 71 of the shutter plate driving mechanism 60 and the filter plate driving mechanism 70 are arranged in a posture lying flat on the subject side surface of the case 22. A rectangular frame-shaped laminated core body 94 is used. Further, the shutter plate 81 and the neutral density filter 86 are disposed on the subject side from the laminated core body 94. For this reason, a space 80 is formed in the central portion of the attached unit 8 on the image sensor 30 side.

  For this reason, in the lens driving device 1 of the present embodiment, as shown in FIGS. 1 and 5A, when the movable lens body 10 is moved to the closest distance position, the small-diameter end 15 on the subject side is attached to the accessory unit. 8 space 80 is entered. For this reason, in the lens driving device 1 of this embodiment, even when the accessory unit 8 is overlapped on the subject side of the lens driving device main body 2 to enhance the function, the size of the lens driving device 1 in the optical axis direction can be short.

  Further, in this embodiment, since the accessory unit 8 is disposed on the subject side with respect to the lens driving device main body 2, it is possible to use a small size as the shutter plate 81 and the neutral density filter 86. That is, in the present embodiment, as shown in FIG. 5B, the accessory unit 8 (the shutter plate 81 and the neutral density filter 86) is disposed on the subject side having a narrow optical path when viewed from the fixed diaphragm 19, and therefore FIG. As shown in FIG. 4B, the shutter plate 81 and the light reducing filter 86 having a small outer diameter are used as compared with the case where the accessory unit 8 (shutter plate and light reducing filter) is disposed on the imaging element 30 side having a wide optical path. Therefore, the lens driving device 1 is suitable for downsizing.

(Other embodiments)
In the above embodiment, the shutter plate 81 and the neutral density filter plate 86 are arranged in the accessory unit 8. However, as such a plate-like optical member, the shutter plate 81 and the neutral density filter plate 86 are used instead. The present invention is applied to a lens driving device in which an aperture plate, a color conversion plate, an infrared filter plate (infrared cut filter plate or infrared transmission filter), and an ultraviolet filter plate (ultraviolet cut filter plate or ultraviolet transmission filter) are mounted in an accessory unit. May be. The core may be a monolithic core that does not have a laminated structure.

  In the above embodiment, two optical members (the shutter plate 81 and the neutral density filter plate 86) are arranged in the accessory unit 8. However, the present invention is applied when any one optical member is arranged. You may apply.

  Further, in the above embodiment, an example of a lens driving device that rotationally drives the rotor by the stator, converts the rotational operation into a linear motion, and linearly magnetically drives the moving lens body along the optical axis of the lens. However, the present invention may be applied to a lens driving device that linearly magnetically drives the moving lens body along the optical axis of the lens.

  Furthermore, in the above embodiment, an example in which the present invention is applied to a lens driving device having an autofocus function has been described. However, a lens driving device having a zoom function instead of the autofocus function or both the autofocus function and the zoom function are described. The present invention may be applied to a lens driving device having

It is sectional drawing of the principal part of the lens drive device to which this invention is applied. FIG. 2 is a plan view of the attached unit shown in FIG. 1 when viewed from the subject side. FIG. 2 is a perspective view of the attached unit shown in FIG. 1 when viewed from the subject side. FIG. 2 is a perspective view when the accessory unit shown in FIG. 1 is viewed from the image sensor side. It is explanatory drawing for demonstrating the effect of the lens drive device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 5 Lens drive mechanism 8 Accessory unit 10 Moving lens bodies 16, 17, 18 Lens 19 Fixed aperture 20 Fixed member 60 Shutter plate drive mechanism (first optical member drive mechanism)
70 Filter plate drive mechanism (second optical member drive mechanism)
81 Shutter plate (plate-like optical member)
86 Attenuating filter plate (plate-like optical member)
90 Base plate 94 Laminated core body 95, 96, 97, 99, 99 Core plate L Optical axis

Claims (5)

In a lens driving device comprising a moving lens body provided with a lens, and a lens driving mechanism for reciprocating the moving lens body along the optical axis of the lens,
Provided on the subject side with respect to the moving lens body is an optical member driving mechanism that drives a plate-like optical member between a position where the optical member appears on the optical path and a position where the optical member is retracted from the optical path The unit is placed,
The lens driving device according to claim 1, wherein the accessory unit includes a space into which an object side end of the moving lens body enters when the moving lens body moves to a close distance position side on the object side. 2. The optical member driving mechanism according to claim 1, comprising a laminated core, a coil wound around the laminated core, and a rotor magnet that is rotationally driven by the coil, and the optical member is rotated by the rotation of the rotor magnet. Configured to drive,
The lens driving device according to claim 1, wherein the optical member is disposed closer to the subject side than the laminated core.   3. The accessory unit according to claim 1, wherein the accessory unit includes at least one optical member selected from a shutter plate, a diaphragm plate, a color conversion plate, a neutral density filter plate, an infrared filter plate, and an ultraviolet filter plate as the optical member. A lens driving device comprising: 2. The accessory unit according to claim 1, wherein at least two optical members selected from a shutter plate, a diaphragm plate, a color conversion plate, a neutral density filter plate, an infrared filter plate, and an ultraviolet filter plate are provided as the optical member. And
The optical member drive mechanism includes a first optical member drive mechanism that drives one of the two optical members, and a second optical component drive mechanism that drives the other optical member. A lens driving device. 5. The first optical component driving mechanism according to claim 4, wherein the first optical component driving mechanism includes a first laminated core, a first stator including a first coil wound around a part of the first laminated core, and the first stator. A first rotor magnet that is rotationally driven by one stator, and is configured to drive the one optical component by the rotation of the first rotor magnet,
The second optical component driving mechanism includes a second stator having a second laminated core and a second coil wound around a part of the second laminated core, and is rotated by the second stator. A second rotor magnet to be driven, and configured to drive the other optical component by rotation of the second rotor magnet,
The first laminated core and the second core are configured as an integral laminated core body,
The one optical component and the other optical component are both disposed closer to the subject side than the laminated core body.

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