JP2008015159A - Lens barrel and optical equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact lens barrel and optical equipment capable of correctly detecting a position. <P>SOLUTION: A light shield plate 20 is disposed between a shutter unit 10 having a shutter blade drive coil 11 and a diaphragm blade drive coil 12 and a position sensor substrate unit 30 having hole elements 31 and 32 mounted thereon. Accordingly, magnetic force generated by the shutter blade drive coil 11 and diaphragm blade drive coil 12 is prevented from reaching the hole elements 31 and 32, and therefore a position can be correctly detected. This makes it possible to dispose shutter blade drive coil 11 and diaphragm blade drive coil 12 and the hole elements 31 and 32 close to each other, thus making the lens barrel compact. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens barrel and an optical apparatus that use a magnetic sensor that performs magnetic detection to detect movement of a measurement object.

  As an apparatus of this type, the shift movement amount of the blur correction optical system is detected when the blur correction optical system, which is a movable lens, is shifted in a plane substantially orthogonal to the optical axis to correct the blur of the image. For this purpose, Patent Document 1 discloses an apparatus using a Hall element.

When such an apparatus is applied to a lens-integrated small camera, the blur correction optical system may be disposed in the vicinity of the shutter unit or the aperture unit.
In such a case, if magnetism generated by an actuator that drives a shutter, a diaphragm, or the like is detected by the Hall element, the position detection accuracy of the blur correction optical system by the Hall element is lowered, which hinders an accurate blur correction operation. There was a problem.
Further, if the actuators are arranged so that the magnetism generated by these actuators does not affect the Hall element, there is a problem that the apparatus cannot be reduced in size.
JP 2004-245765 A

  An object of the present invention is to provide a small lens barrel and an optical apparatus that can accurately detect a position.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention according to claim 1 is provided between the magnetic sensor (31, 32) for sensing magnetism, the actuator (11, 12) for generating a magnetic force at least during driving, and between the magnetic sensor and the actuator. And a magnetic shielding member (20) for reducing the intensity of magnetism reaching the magnetic sensor.
According to a second aspect of the present invention, in the lens barrel according to the first aspect, the magnetic shielding member (20) includes the magnetic sensor (31, 32) and the actuator (11, 12) in a direction along the optical axis. The lens barrel is arranged at a position sandwiched between the two.
According to a third aspect of the present invention, in the lens barrel according to the first or second aspect of the present invention, the lens barrel includes a blur correction optical system (L3) provided so as to be movable in a direction orthogonal to the optical axis, and the magnetic sensor (31). , 32) are used for position detectors (31, 32, 51, 52, 55, 56) that detect movement of the shake correction optical system, and the actuators (11, 12) use the shake correction optical system. It is at least one of a shutter actuator (11) that drives a shutter that blocks a light beam that passes through and a diaphragm actuator (12) that drives a diaphragm that restricts the light beam that passes through the blur correction optical system. It is a lens barrel.
According to a fourth aspect of the present invention, in the lens barrel according to any one of the first to third aspects, when viewed from the optical axis direction, the magnetic sensor (31, 32) and the actuator ( 11, 12) is a lens barrel characterized by being arranged in one of two regions divided by a straight line (A) passing through the optical axis.
According to a fifth aspect of the present invention, in the lens barrel according to any one of the first to fourth aspects, the magnetic shielding member (20) is made of a high permeability magnetic alloy. This is a featured lens barrel.
A sixth aspect of the present invention is an optical apparatus including the lens barrel according to any one of the first to fifth aspects.
In addition, you may improve suitably the structure which attached | subjected the code | symbol. In addition, at least a part may be replaced with another component, and the configuration requirements that are not particularly limited with respect to the configuration are not limited to the configurations disclosed in the embodiments.

  According to the present invention, since the magnetic shielding member is provided between the magnetic sensor and the actuator, position detection can be performed accurately, and a small lens barrel and optical device can be obtained.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

(Embodiment)
FIG. 1 is a cross-sectional view of a main part of a camera including a lens barrel of the present embodiment cut along an optical axis.
In addition, in FIG. 1 and the following figures that can indicate the coordinate axes, XYZ orthogonal provided with the upper side as the Y plus direction when the camera is in the normal position for easy understanding. Coordinates are also shown. The right side when viewed from the subject side in the optical axis direction is the X plus direction, and the subject side in the optical axis direction is the Z plus direction. Here, the positive position indicates the posture of the camera in which the optical axis O of the photographing optical system is horizontal and the longitudinal direction of the photographing screen is the horizontal direction.
The lens barrel of the present embodiment is fixed to an image sensor fixing unit 2 that fixes the image sensor 1 and the low-pass filter 1a, and forms the main part of the camera.
The lens barrel of this embodiment includes a fixed barrel 3, a cam barrel 4, a first group cylinder 5, a third group cylinder 6, an intermediate cylinder 7, a second group cylinder 8, a fourth group frame 9, a shutter VR unit 100, and the like. The photographic optical system has a four-group configuration of one lens unit L1, a second lens unit L2, a third lens unit L3, and a fourth lens unit L4.

The fixed cylinder 3 has a female helicoid formed on the inner periphery and is fixed to the image sensor fixing portion 2.
The cam cylinder 4 is disposed on the inner peripheral side of the fixed cylinder 3, and a male helicoid provided on the outer periphery is screwed into the female helicoid of the fixed cylinder 3. A cam groove is spirally provided on the inner periphery of the cam cylinder 4.
The first group cylinder 5 is disposed on the inner peripheral side of the cam cylinder 4 and has a cam follower (not shown) on the outer periphery. The cam follower is cam-engaged with the cam groove of the cam cylinder 4. The first group cylinder 5 holds the first lens group L1 via the first group frame 5a. In addition, a barrier mechanism 5b that covers and protects the first lens unit L1 when the camera is not used (a retracted state of the lens barrel) is provided at the subject-side tip of the first group tube 5.

  The third group cylinder 6 is disposed on the inner peripheral side of the first group cylinder 5, is rotatable relative to the image side end portion of the cam cylinder 4, and moves with the cam cylinder 4 in the optical axis direction. Is provided. A rectilinear guide 6a is fixed on the image side of the third group cylinder 6, and the rotation of the third group cylinder 6 is restricted. Therefore, the third group cylinder 6 moves in the optical axis direction according to the movement of the cam cylinder 4 without rotating. Further, the VR main unit 40 included in the shutter VR unit 100 is fixed to the third group cylinder 6.

The intermediate cylinder 7 is disposed on the inner peripheral side of the third group cylinder 6, and a follower pin (not shown) is fixed thereto. This follower pin is engaged with the cam groove of the cam cylinder 4 through a straight advance groove (not shown) provided in the third group cylinder 6 along the optical axis direction. Therefore, when the cam cylinder 4 rotates, the intermediate cylinder 7 moves in the optical axis direction.
The second group cylinder 8 holds the second lens unit L2 via the second group frame 8a, is disposed on the inner peripheral side of the intermediate cylinder 7, and is fitted to the intermediate cylinder 7 by a fitting portion (not shown). Thus, it can move in the optical axis direction with respect to the intermediate cylinder 7. The second group cylinder 8 changes its position in the optical axis direction with respect to the intermediate cylinder 7 from the retracted position to the wide-angle position to the telephoto position.
The fourth group frame 9 holds the fourth lens group L4, is supported by a guide shaft and a rotation stop shaft (not shown), and is movable along the optical axis direction. The fourth group frame 9 is driven in the optical axis direction by obtaining a driving force from a stepping motor (not shown).

FIG. 2 is a perspective view showing a state in which the shutter VR unit 100 of the present embodiment is assembled.
FIG. 3 is an exploded perspective view of the shutter VR unit 100 of the present embodiment as viewed from the subject side.
FIG. 4 is an exploded perspective view of the shutter VR unit 100 of the present embodiment as viewed from the image sensor side.
FIG. 5 is a cross-sectional view of the shutter VR unit 100 cut along the Y-axis.
FIG. 6 is a view of the shutter unit 10, the Hall elements 31, 32, and the VCM coils 53, 54 as viewed from the image side in the optical axis direction.
The VCM (Voice Coil Motor) indicates an actuator that generates a driving force for driving a movable VR unit 50 described later.
The shutter VR unit 100 includes a shutter unit 10, a shielding plate 20, a position sensor board unit 30, a VR main body unit 40, a movable VR unit 50, a lid unit 60 and the like in order from the subject side.

The shutter unit 10 includes a shutter blade (not shown) and its driving mechanism, a diaphragm blade (not shown) and its driving mechanism, and is fixed to the VR main unit 40. The shutter unit 10 includes a shutter blade driving coil 11 that is a part of an actuator that generates a driving force for driving a shutter driving mechanism and a part of an actuator that generates a driving force for driving a diaphragm blade driving mechanism. A certain diaphragm blade driving coil 12 is provided exposed to the image side. As shown in FIG. 6, the shutter blade driving coil 11 is arranged on the Y plus side with respect to the optical axis O, and the diaphragm blade driving coil 12 is on the X plus side and Y minus with respect to the optical axis O. It is arranged at the position that becomes the side.
The shielding plate 20 is a plate-like member formed of permalloy, which is a high magnetic permeability magnetic alloy. The shielding plate 20 is disposed at a position sandwiched between the shutter unit 10 and the position sensor substrate unit 30 and is fixed between the shutter unit 10 and the VR main unit 40. Details of the shielding plate 20 will be described later.

The position sensor board unit 30 is a flexible board on which Hall elements 31 and 32 for detecting the position in the XY plane of a movable VR unit 50 described later are mounted.
The hall element 31 is a sensor that detects a position of the movable VR unit 50 in the Y-axis direction by detecting a change in magnetism generated by a hall element magnet 51 described later. The hall element 31 is inserted and fixed in a hole 40 a provided in the VR main body unit 40.
The hall element 32 is a sensor that detects a change in magnetism generated by a hall element magnet 52 described later and detects the position of the movable VR unit 50 in the X-axis direction. The hall element 32 is inserted into and fixed to the hole 40 b provided in the VR main body unit 40, similarly to the hall element 31.
The position sensor board unit 30 is connected to a lens CPU (not shown) and transmits a signal corresponding to the magnetism detected by the Hall elements 31 and 32 to the lens CPU. The lens CPU calculates the position of the movable VR unit 50 based on the signal corresponding to the obtained magnetism.

The VR main body unit 40 has a substantially cylindrical shape, and is a part that holds a movable VR unit 50, which will be described later, so as to be movable and serves as a base of a shake correction mechanism. As described above, the VR main body unit 40 is fixed to the third group cylinder 6 and moves together with the third group cylinder 6 in the optical axis direction. In addition to the Hall elements 31 and 32 described above, VCM yokes 41 and 42 are fixed to the VR main body unit 40 on the image side surface.
The hall element 31 is disposed on the Y plus side with respect to the optical axis O, and the VCM yoke 41 is disposed on the Y minus side with respect to the optical axis O. The Hall element 32 is disposed on the X plus side with respect to the optical axis O, and the VCM yoke 42 is disposed on the X minus side with respect to the optical axis O.

  The movable VR unit 50 holds the third lens unit L3, is disposed in the VR main body unit 40, and is provided so as to be movable in an XY plane orthogonal to the optical axis O. The third lens unit L3 is a blur correction optical system that can move the position of an image formed on the image sensor 1 by moving in a direction orthogonal to the optical axis O. In the lens barrel of the present embodiment, the third lens group L3 held by the movable VR unit 50 is placed on the optical axis O in accordance with camera shake caused by camera shake detected by a shake detection unit having an angular velocity sensor (not shown). An image blur correction operation for reducing image blur is performed by moving in an orthogonal plane.

FIG. 7 is a cross-sectional view showing a portion where the VR main unit 40 supports the movable VR unit 50.
FIG. 8 is a cross-sectional view showing a portion that biases the movable VR unit 50 toward the VR main unit 40.
Three balls 43 are provided between the movable VR unit 50 and the VR main body unit 40. In addition, a tension coil spring 44 is stretched between the movable VR unit 50 and the VR main body unit 40 to urge the VR main body unit 40 toward the movable VR unit 50 side. Therefore, the movable VR unit 50 can move smoothly in the XY plane with respect to the VR main body unit 40.

3 to 6, in the movable VR unit 50, a hall element magnet 51 and a hall element yoke 55 are fixed at a position corresponding to the hall element 31, and a hole is located at a position corresponding to the hall element 32. The element magnet 52 and the hall element yoke 56 are fixed. The hall element magnets 51 and 52 are provided on the subject side of the movable VR unit 50, and the hall element yokes 55 and 56 are provided on the image side of the movable VR unit 50.
In the movable VR unit 50, a VCM coil 53 is fixed at a position corresponding to the VCM yoke 41, and a VCM coil 54 is fixed at a position corresponding to the VCM yoke 42.
Further, on the image side of the movable VR unit 50, VCM flexible boards 57 and 58 for energizing the VCM coils 53 and 54 are provided.

The lid unit 60 is formed by pressing a metal plate, and is a member that is disposed so as to cover the VR main body unit 40 including the movable VR unit 50 from the image side. The lid unit 60 has three engaging portions 60 a that are bent so as to protrude toward the subject, and the engaging portions 60 a engage with engaging protrusions 40 c provided on the outer peripheral side of the VR main body unit 40. It is fixed by.
In the lid unit 60, a VCM magnet 61 and a VCM yoke 63 are fixed at a position corresponding to the VCM coil 53, and a VCM magnet 62 and a VCM yoke 64 are fixed at a position corresponding to the VCM coil 54. Has been. The VCM magnets 61 and 62 are provided on the subject side of the lid unit 60, and the VCM yokes 63 and 64 are provided on the image side of the lid unit 60.

In summary, the VCM yoke 41, the VCM coil 53, the VCM magnet 61, and the VCM yoke 63 form a VCM that generates a driving force in the Y-axis direction, and the VCM yoke 42 and the VCM coil. 54, the VCM magnet 62 and the VCM yoke 64 form a VCM that generates a driving force in the X-axis direction. Further, a position detector for detecting the position of the movable VR unit 50 in the Y-axis direction is formed by the Hall element 31, the Hall element magnet 51, and the Hall element yoke 55, and the Hall element 32, the Hall element magnet 52, and the Hall element are detected. A position detector for detecting the position of the movable VR unit 50 in the X-axis direction is formed by the yoke 56.
Therefore, the movable VR unit 50 can be driven with respect to the VR main body unit 40 on the XY plane orthogonal to the optical axis O while being position-controlled, and can perform a blur correction operation.

  Here, since the Hall elements 31 and 32 detect the position of the movable VR unit 50 by detecting a change in magnetism, as described above, magnetism other than the magnetism generated by the Hall element magnets 51 and 52 is detected. If detected, the position detection accuracy may be affected. In the present embodiment, the shutter blade driving coil 11 and the diaphragm blade driving coil 12 can be considered to have the possibility of having a magnetic effect on the Hall elements 31 and 32 other than the Hall element magnets 51 and 52. And VCM coils 53 and 54 and VCM magnets 61 and 62.

  As can be seen from FIG. 6, the Hall elements 31 and 32 are sufficiently separated from the VCM coils 53 and 54 in the XY plane direction. Therefore, the Hall elements 31 and 32 are hardly affected by the magnetism of the VCM coils 53 and 54 and the VCM magnets 61 and 62.

  However, the shutter blade driving coil 11 and the diaphragm blade driving coil 12 are concentrated on the upper left side of the straight line A passing through the optical axis O shown in FIG. The coil 11 and the hall element 31 are arranged so as to overlap in FIG. Further, the shutter blade driving coil 11 and the diaphragm blade driving coil 12 and the Hall elements 31 and 32 are close to each other in the optical axis direction (see FIG. 5). Accordingly, the magnetic elements generated by the Hall elements 31 and 32 from the shutter blade driving coil 11 and the diaphragm blade driving coil 12 simply by arranging the Hall elements 31 and 32, the shutter blade driving coil 11 and the diaphragm blade driving coil 12 as they are. The position detection accuracy may be affected by the influence of the above.

Therefore, in this embodiment, the shielding plate 20 is provided between the shutter unit 10 having the shutter blade driving coil 11 and the diaphragm blade driving coil 12 and the position sensor substrate unit 30 on which the Hall elements 31 and 32 are mounted. Is provided.
As described above, the shielding plate 20 is made of permalloy, which is a high permeability magnetic alloy. This permalloy has a characteristic that magnetic permeability is very high and magnetism easily passes through the inside. Since the shielding plate 20 has this characteristic, the magnetism that has reached the shielding plate 20 is more likely to travel in the shielding plate 20 than to pass through as it is, so that the shielding is performed along the plate surface direction of the shielding plate 20. Proceed through the plate 20. Therefore, the magnetism that has reached the shielding plate 20 does not pass through as it is and reaches the Hall elements 31 and 32, and the shielding plate 20 functions as a magnetic shielding member.

FIG. 9 is a view of the shutter blade driving coil 11, the diaphragm blade driving coil 12, the shielding plate 20, the Hall elements 31 and 32, and the VCM coils 53 and 54 viewed from the image sensor side in the optical axis direction.
In the present embodiment, the shielding plate 20 is disposed on the XY plane orthogonal to the optical axis O so as to overlap all of the shutter blade driving coil 11, the diaphragm blade driving coil 12, and the Hall elements 31 and 32. Therefore, the shielding plate 20 can shield the magnetism generated by the shutter blade driving coil 11 and the diaphragm blade driving coil 12 from reaching the Hall elements 31 and 32.

According to the present embodiment, since the shielding plate 20 is provided between the shutter blade driving coil 11 and the diaphragm blade driving coil 12 which are actuators that generate magnetism and the Hall elements 31 and 32, the shutter blade driving coil. 11 and the Hall elements 31 and 32 can accurately detect the position without being affected by the magnetism generated by the diaphragm blade driving coil 12. Further, since the shutter blade driving coil 11 and the diaphragm blade driving coil 12 and the Hall elements 31 and 32 can be brought close to each other, the whole can be reduced in size.
The portion where the VCM is formed requires a large arrangement space in the optical axis direction, whereas the portion where the Hall elements 31 and 32 are formed has a small arrangement space in the optical axis direction. Therefore, it is convenient to reduce the overall size by arranging the Hall elements 31 and 32 so that the shutter blade driving coil 11 and the diaphragm blade driving coil 12 overlap in the XY plane.

(Deformation)
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
(1) In this embodiment, although the example which uses Hall elements 31 and 32 as a sensor which detects the position of movable VR unit 50 was shown, not only this but MI (Magneto Impedance) sensor, a magnetic resonance type, for example Other magnetic sensors that sense magnetism, such as a magnetic field detection element and an MR (Magneto-Resistance) element, may be used.

(2) In the present embodiment, the digital camera has been described as an example. However, the present invention is not limited to this, and other optical devices such as a video camera, a field scope, and binoculars may be used.

(3) In the present embodiment, the shielding plate 20 has shown an example of shielding the magnetism generated by the shutter blade driving coil 11 and the diaphragm blade driving coil 12. However, the present invention is not limited to this. The generated magnetism may be shielded. In addition to the magnetism generated by the actuator that drives the lens, for example, in a lens barrel that includes a shake correction mechanism that drives the image sensor and performs a shake correction operation, the magnetism generated by the actuator that drives the image sensor is shielded. You may shield with a board.

(4) In the present embodiment, the example of using the permalloy is shown as the material of the shielding plate 20, but is not limited thereto, and any material that can reduce the magnetism transmitted to the Hall elements 31 and 32 may be used.

It is sectional drawing which cut | disconnected the principal part of the camera containing the lens-barrel of this embodiment by the optical axis. It is a perspective view which shows the state which assembled the shutter VR unit 100 of this embodiment. It is the disassembled perspective view which looked at the shutter VR unit 100 of this embodiment from the to-be-photographed object side. It is the disassembled perspective view which looked at the shutter VR unit 100 of this embodiment from the image sensor side. It is sectional drawing which cut | disconnected the shutter VR unit 100 along the Y-axis. It is the figure which looked at the shutter unit 10, Hall elements 31, 32, and VCM coils 53, 54 from the image side in the optical axis direction. FIG. 5 is a cross-sectional view showing a portion where the VR main unit 40 supports the movable VR unit 50. It is sectional drawing which shows the part which urges the movable VR unit 50 to the VR main body unit 40 side. It is the figure which looked at the shutter blade drive coil 11, the aperture blade drive coil 12, the shielding plate 20, the Hall elements 31, 32, and the VCM coils 53, 54 from the image sensor side in the optical axis direction.

Explanation of symbols

11: Coil for driving shutter blade, 12: Coil for driving diaphragm blade, 31, 32: Hall element, 20: Shield plate, 53, 54: Coil for VCM

Claims (6)

A magnetic sensor for sensing magnetism;
An actuator that generates magnetic force at least during driving;
A magnetic shielding member which is provided between the magnetic sensor and the actuator and reduces the strength of magnetism reaching the magnetic sensor from the actuator;
A lens barrel comprising: The lens barrel according to claim 1,
The magnetic shielding member is disposed at a position sandwiched between the magnetic sensor and the actuator in a direction along the optical axis;
A lens barrel characterized by In the lens barrel according to claim 1 or 2,
Provided with a blur correction optical system that is movable in a direction perpendicular to the optical axis,
The magnetic sensor is used in a position detection unit that detects movement of the blur correction optical system,
The actuator is at least one of a shutter actuator that drives a shutter that blocks a light beam that passes through the blur correction optical system and a diaphragm actuator that drives a diaphragm that restricts the light beam that passes through the blur correction optical system;
A lens barrel characterized by The lens barrel according to any one of claims 1 to 3, wherein
When viewed from the optical axis direction, the magnetic sensor and the actuator are arranged in one of two regions divided by a straight line passing through the optical axis,
A lens barrel characterized by In the lens barrel according to any one of claims 1 to 4,
The magnetic shielding member is made of a high permeability magnetic alloy;
A lens barrel characterized by An optical apparatus comprising the lens barrel according to any one of claims 1 to 5.

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