JP2010152220A - Optical vibration isolation apparatus and optical equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve smooth moving of a holding member that holds an optical element relative to a base member, while applying proper moving resistance to the holding member so as to make controllability of a position of the holding member excellent. <P>SOLUTION: The optical vibration isolation apparatus 3 includes the base member 301, the holding member 313 that holds the optical element L3, and actuators 401 to 403 that move the holding member in a direction different from an optical axis direction relative to the base member. A first member that is one of the base member and the holding member has a projection 313c projecting toward a second member that is the other member. Grease 801 having viscosity is arranged between the projection and the second member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical image stabilizer that is mounted on an optical apparatus such as a digital video camera, a digital still camera, and an interchangeable lens to reduce image blur.

  The above-mentioned optical image stabilization apparatus moves an optical element such as a correction lens in a direction different from the optical axis direction (for example, a direction orthogonal to the optical axis direction) in accordance with the shake of the optical apparatus. Reduce.

Patent Document 1 discloses an example of an optical image stabilizer. In this apparatus, the base of the holding member is disposed between a holding member (holding barrel) that holds the correction lens and a base member (supporting barrel) that supports the holding member so as to be movable in a direction orthogonal to the optical axis direction. A plurality of balls that roll as the member moves are arranged. The ball reduces movement resistance (friction resistance) of the holding member relative to the base member to enable smooth movement of the holding member, and keeps the distance between the holding member and the base member in the optical axis direction constant. Therefore, it has a role to prevent deterioration of the optical performance of the apparatus. The holding member is driven with respect to the base member by a thrust generated by an electromagnetic actuator including a coil and a magnet.
JP 2001-290184 A

  However, in the optical image stabilizer disclosed in Patent Document 1, the friction (movement resistance) acting between the holding member and the base member is basically only a small rolling friction caused by a plurality of balls. For this reason, even if the thrust of the electromagnetic actuator or the change thereof is small, the holding member moves greatly, and the controllability of the position of the holding member may be lowered.

  Further, even in an optical anti-vibration device other than the type in which the holding member is guided by the ball (for example, a type in which the holding member is guided in the direction orthogonal to the optical axis direction by the guide bar), the frictional resistance (movement resistance) acting on the holding member. If it is too small, similar problems arise.

  The present invention enables smooth movement of the holding member (optical element) with respect to the base member while imparting an appropriate movement resistance to the holding member so that the controllability of the position of the holding member can be improved. An optical vibration isolator and an optical apparatus are provided.

  An optical image stabilizer as one aspect of the present invention includes a base member, a holding member that holds an optical element, and an actuator that moves the holding member in a direction different from the optical axis direction with respect to the base member. The first member, which is one of the base member and the holding member or a member fixed to the one member, is the second member, which is a member fixed to the other member or the other member. Protrusions projecting toward the member. And the grease which has viscosity is arrange | positioned between the projection part and the 2nd member, It is characterized by the above-mentioned.

  Note that the optical apparatus having the optical image stabilizer also constitutes another aspect of the present invention.

  According to the present invention, it is possible to improve the controllability of the position of the holding member by applying an appropriate movement resistance due to the viscosity of the grease to the holding member via the protrusion.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 shows a configuration of an optical apparatus (hereinafter referred to as a camera) such as a video camera or a digital still camera that is Embodiment 1 of the present invention.

  In FIG. 2, L is a lens barrel containing a zooming photographic optical system, and B is a camera body. In the camera body B, an image pickup device (to be described later) for recording a subject image formed by the photographing optical system is housed.

  3 and 4 show the lens barrel L in an exploded manner. The photographing optical system is a variable magnification optical system (zoom lens system) configured by four lens units of convex, concave, convex, and convex in order from the object side (left side of each figure) to the image plane side. AXL in FIG. 4 indicates the optical axis of the photographing optical system. In the following description, the direction in which the optical axis AXL extends is referred to as the optical axis direction. The subject side in the optical axis direction is referred to as the front side, and the image plane side is referred to as the rear side. Further, a rotation direction around the optical axis AXL is referred to as a circumferential direction or a direction around the optical axis.

  L1 is a first lens unit. L2 is a second lens unit that moves in the optical axis direction and performs zooming. L3 is a third lens unit (optical element) that moves in a direction orthogonal to the optical axis as a direction different from the optical axis direction (hereinafter referred to as the optical axis orthogonal direction) to perform optical image stabilization (image blur correction). . L4 is a fourth lens unit that moves in the optical axis direction to adjust the focus. Reference numeral 601 denotes an imaging element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor.

  Reference numeral 5 denotes a front lens barrel, and reference numeral 6 denotes a rear lens barrel that holds the image sensor 601. 312 is the 1st ground plane which comprises a part of shift unit 3 mentioned later. The front lens barrel 5 and the rear lens barrel 6 sandwich the first base plate 312 in the optical axis direction and are coupled by screws to constitute a fixed lens barrel of the lens barrel L.

  Reference numeral 1 denotes a front lens holding frame that holds the first lens unit L <b> 1, and is coupled to the front end portion of the front barrel 5.

  Reference numeral 2 denotes a variator moving frame that holds the second lens unit L2, and is guided by the guide bars 8 and 9 in the optical axis direction. 201 is a stepping motor that drives the variator moving frame 2 in the optical axis direction. A lead screw 202 is formed on the output shaft of the stepping motor 201. The stepping motor 201 is fixed to the fixed barrel 5 with a screw via a support plate 210.

  A rack 203 attached to the variator moving frame 2 is engaged with the lead screw 202. For this reason, when the lead screw 202 is rotated by energizing the stepping motor 201, the variator moving frame 2 is driven in the optical axis direction together with the second lens unit L2.

  Reference numeral 205 denotes a zoom reset switch, which includes a photo interrupter. The zoom reset switch 205 detects that the variator moving frame 2 is located at a predetermined reference position by switching from the light receiving state to the light blocking state due to the movement of the light blocking portion 206 formed on the variator moving frame 2 in the optical axis direction. To do.

  Reference numeral 7 denotes a light amount adjustment unit for adjusting the amount of light incident on the image sensor 601 through the photographing optical system, and moves the two diaphragm blades 701 in the direction orthogonal to the optical axis to change the aperture diameter. The light quantity adjustment unit 7 is provided with an ND filter (not shown) so as to advance and retreat with respect to the optical path independently of the diaphragm blades.

  Reference numeral 3 denotes a shift unit as an optical image stabilizer. The detailed configuration of the shift unit 3 will be described later.

  Reference numeral 4 denotes a focus movement frame that holds the fourth lens unit L4, and is guided in the optical axis direction by the guide bars 10 and 11. 401 is a coil, and 402 is a drive magnet. Reference numerals 403 a and 403 b denote yokes for closing a magnetic flux generated between the coil 401 and the drive magnet 402. The coil 401, the drive magnet 402, and the yokes 403a and 403b constitute a focus motor (voice coil motor) that drives the focus moving frame 4 in the optical axis direction.

  When a current is passed through the coil 401, a Lorentz force is generated due to repulsion between the lines of magnetic force generated between the coil 401 and the magnet 402, and the fourth lens unit L4 is driven in the optical axis direction together with the focus moving frame 4. .

  Further, the focus moving frame 4 holds a sensor magnet (not shown) magnetized in a multipolar manner in the optical axis direction, and a magnetic field line accompanying the movement of the sensor magnet is located at a position facing the sensor magnet in the rear barrel 6. An MR sensor 404 for reading the change is fixed by screws. By using a signal from the MR sensor 404, it is possible to detect the amount of movement of the focus moving frame 4, that is, the fourth lens unit L4 from a predetermined reference position.

  Hereinafter, the configuration of the shift unit 3 will be described with reference to FIGS. 3, 4 and 1. Reference numeral 301 denotes a second ground plate fixed to the rear end of the first ground plate 312 with screws. The second ground plane 301 holds pitch driving and yaw driving magnets 303 and two yokes 302 arranged on the rear side of these magnets 303. Each magnet 303 is magnetized so that an N pole and an S pole are formed in the direction perpendicular to the optical axis. The first base plate 312 and the second base plate 301 constitute a base member of the shift unit 3. Moreover, in the following description, the 1st ground plane 312 and the 2nd ground plane 301 are collectively called ground plane 301,312.

  Reference numeral 313 denotes a shift barrel (holding member) that holds the third lens unit L3 and can move (shift) in the pitch direction and the yaw direction that are orthogonal to the optical axis with respect to the base plates 301 and 312. The shift barrel 313 is disposed between the first ground plane 312 and the second ground plane 301.

  The shift barrel 313 holds the pitch driving and yaw driving coils 308 at positions facing the pitch driving and yaw driving magnets 303 in the optical axis direction. Further, the shift barrel 313 holds two yokes 311 disposed on the rear side of these two coils 308. In FIG. 1, the yoke 311 is not shown.

  When each coil 308 is energized, Lorentz force is generated by the repulsion between the magnetic field generated in the coil 308 and the magnetic field generated by the magnet 303. The shift barrel 313 is driven to shift in the pitch direction and the yaw direction by the Lorentz force generated by energizing the coil 308 for pitch driving and yaw driving.

  The coil 308, the magnet 303, and the yokes 302 and 311 constitute an anti-vibration actuator (electromagnetic actuator) that drives the shift barrel 313 in the direction orthogonal to the optical axis.

  Energization of the coil 308 includes a camera shake detected by a shake sensor (not shown) (an angular velocity sensor or the like) and a shift position of the shift barrel 313 detected by a position sensor (not shown) provided in the shift unit 3. Is controlled by a controller (not shown).

  One ball 320 is arranged between the shift barrel 313 and the second ground plane 301. In addition, the shift barrel 313 as the first member, which is one of the shift barrel 313 and the second ground plate 301, has two cylindrical projections projecting to the rear side (second ground plate 301 side). 313c is formed. One ball 320, two protrusions 313c, and three positions at substantially equal angle (120 degrees) intervals in the circumferential direction (around the optical axis) of the shift unit 3 are provided.

  On the other hand, on the front surface of the second base plate 301 as the second member which is the other member of the shift barrel 313 and the second base plate 301, as shown in FIG. Is formed. The ball 320 abuts on a surface corresponding to the bottom surface of the ball receiving recess 301b (hereinafter referred to as a ball receiving surface). Although not shown, a similar ball receiving recess is formed on the rear surface of the shift barrel 313, and the ball 320 abuts on a ball receiving surface corresponding to the bottom surface of the ball receiving recess.

  In addition, a projection receiving recess 301a into which the protruding portion 313c is inserted is formed on the front surface of the second ground plate 301, and the front end surface (rear end surface) of the protruding portion 313c corresponds to the bottom surface of the protruding receiving recess 301a. Abutting on a surface (hereinafter referred to as a projection receiving surface).

  A biasing force to the rear side (second ground plane 301 side) by a biasing member such as a spring (not shown) or a magnetic biasing mechanism acts on the shift barrel 313. For this reason, the ball 320 is pressed against the ball receiving surfaces of the second base plate 301 and the shift barrel 313. The ball 320 rolls in the ball receiving recess as the shift barrel 313 is shifted with respect to the base plates 301 and 312. When the ball 320 rolls, the frictional resistance generated between the ball 320 and each ball receiving surface when the shift barrel 313 shifts with respect to the second ground plate 301 (that is, the movement resistance of the shift barrel 313). ) Can be reduced.

  As described above, in this embodiment, the ball 320 is brought into contact with the shift barrel 313 and the second base plate 301 at one of the three circumferential directions, and the protrusion 313c provided on the shift barrel 313 at two locations. Is brought into contact with the second base plate 301. Thereby, the shift barrel 313 is positioned with respect to the base plates 301 and 312 in the optical axis direction, and the tilt with respect to the optical axis is prevented.

  Further, as shown in FIG. 5, viscous grease 801 is disposed inside the two protrusion receiving recesses 301 a of the second ground plate 301. A thin film is formed by grease 801 between the tip surface of the protrusion 313c (hereinafter referred to as the protrusion end surface) and the protrusion receiving surface of the protrusion receiving recess 301a, so that when the shift barrel 313 is shifted, The frictional resistance generated between the projection receiving surface and the projection receiving surface can be reduced. Even if a thin film of grease 801 is interposed between the projection end surface and the projection receiving surface, the projection end surface and the projection receiving surface are considered to be in contact with each other. In other words, the protrusion end surface and the protrusion receiving surface are in contact with each other through the thin film of the grease 801.

  In addition, due to the viscosity of the grease 801, an appropriate movement resistance can be imparted to the shift barrel 313 via each protrusion 313c. Thereby, by arranging the balls at all three positions in the circumferential direction, the movement resistance of the shift barrel 313 becomes too small, and the controllability of the position of the shift barrel 313 through the vibration-proof actuator is avoided. be able to.

  In order to appropriately set the movement resistance of the shift barrel 313, the viscosity (viscosity) of the grease 801 may be adjusted, or the contact area between the protrusion end surface and the protrusion receiving surface may be increased or decreased.

  Further, the depth of the protrusion receiving recess 301a is set so that the grease 801 does not scatter and adhere to the periphery, particularly the third lens unit L3.

  As described above, in this embodiment, the ball is not disposed at all three positions in the circumferential direction between the main plates 301 and 312 and the shift barrel 313, but the shift mirror is disposed at a part of the three positions. A protrusion 313c formed on the cylinder 313 is disposed. A viscous grease 801 is disposed inside the protrusion receiving recess 301a having a protrusion receiving surface with which the protrusion 313c abuts. As a result, as in the case where balls are arranged at three locations in the circumferential direction, the shift barrel 313 is prevented from falling over the optical axis while ensuring smooth movement, while an appropriate movement resistance is applied to the shift barrel 313. Controllability of the position of the shift barrel 313 can be improved.

  FIG. 6 shows the configuration of a shift unit mounted on a camera that is Embodiment 2 of the present invention. The configuration of the camera according to the present embodiment is basically the same as the configuration described in the first embodiment, and thus the description thereof is omitted. Further, in the present embodiment, the same reference numerals as those in the first embodiment are given to components common to the first embodiment, and the same names are given to the components having the same functions as those in the first embodiment.

  Also in the present embodiment, cylindrical protrusions 313c are formed at two locations in the circumferential direction of the shift barrel 313.

  Reference numeral 321 denotes a movement restricting member, which is disposed between the shift barrel 313 and the second main plate 301 '. The protrusions 313c provided at two locations in the circumferential direction of the shift barrel 313 are inserted into two protrusion receiving grooves (recesses) 321b formed in the movement restricting member 321, and the front end surface of the protrusion 313c It abuts on the projection receiving surface corresponding to the bottom surface of the groove 321b.

  The protrusion receiving groove 321b is formed as a long groove extending in the yaw direction, and allows the protrusion 313c to move in the yaw direction, while engaging with the protrusion 313c in the pitch direction. For this reason, the movement limiting member 321 moves together with the shift barrel 313 only in the pitch direction.

  In addition, cylindrical protrusions 321a are formed on the back surfaces (surfaces on the second ground plane 301 ′ side) of the two protrusion receiving groove portions 321b in the movement limiting member 321, respectively. The protrusions 321a are inserted into protrusion receiving grooves (recesses) 301a ′ formed at two locations in the circumferential direction of the second ground plane 301 ′, and the tip surface of the protrusion 321a corresponds to the bottom surface of the protrusion receiving groove 301a ′. Abuts against the protrusion receiving surface.

  The protrusion receiving groove 301a ′ is formed as a long groove extending in the pitch direction, allows the protrusion 321a to move in the pitch direction, and engages with the protrusion 321a in the yaw direction. For this reason, the movement limiting member 321 is fixed to the second ground plane 301 ′ only in the yaw direction.

  In this embodiment, when the shift barrel (one member) 313 is the first member, the movement limiting member 321 is fixed to the second ground plane (the other member) 301 ′ in the yaw direction. It corresponds to the member. Further, when the second ground plate (the other member) 301 ′ is the second member, the movement limiting member 321 is a first member fixed to the shift barrel (one member) 313 in the pitch direction. Equivalent to.

  Further, a ball 320 is disposed between a ball receiving recess (not shown) formed in the shift barrel 313 and a ball holding groove 321 c formed as a long groove extending in the yaw direction on the movement restriction member 321. The ball 320 contacts the ball receiving surface corresponding to the bottom surface of the ball receiving recess and the long side portion of the ball holding groove 321c on the shift lens barrel 313 side.

  Further, another ball 320 is disposed between the ball holding groove portion 321c and the ball receiving groove portion 301b ′ formed as a long groove portion extending in the pitch direction at one place in the circumferential direction of the second base plate 301 ′. The ball 320 abuts on a long side portion of the ball holding groove portion 321c on the second ground plane 301 side and a ball receiving surface corresponding to the bottom surface of the ball receiving groove portion 301b ′.

  In this embodiment, in the optical axis direction, the tip surface of the projection 313c of the shift barrel 313 abuts on the projection receiving surface of the projection receiving groove 321b of the movement limiting member 321 and further the tip of the projection 321a of the movement limiting member 321. The surface comes into contact with the projection receiving surface of the second ground plane 301 '. One ball 320 abuts on the ball receiving surface of the shift barrel 313 and the ball holding groove 321c of the movement restricting member 321, and another ball 320 further receives the ball holding groove 321c and the ball receiving of the second ground plate 301 ′. Contact the surface.

  With such a configuration, the third lens unit L3 is positioned in the optical axis direction with respect to the ground planes 301 ′ and 312 while dividing the guide mechanism of the shift barrel 313 in the yaw direction and the pitch direction.

  In this embodiment, as shown in FIG. 7, viscous grease 801 is disposed inside the protrusion receiving groove 321 b of the movement limiting member 321 and inside the protrusion receiving groove 301 a ′ of the second ground plane 301 ′. Has been. A thin film is formed by the grease 801 between the tip end surface (projection end surface) of the projection 313 c of the shift barrel 313 and the projection receiving surface of the projection receiving groove 321 b of the movement limiting member 321. Similarly, a thin film is formed by the grease 801 between the tip end surface (projection end surface) of the protrusion 321a of the movement restricting member 321 and the protrusion receiving surface of the protrusion receiving groove 301a ′ of the second ground plate 301 ′.

  Thereby, when the shift barrel 313 is shifted, the frictional resistance generated between each projection end surface and the projection receiving surface in contact with the projection end surface can be reduced. Note that even if a thin film of grease 801 is interposed between the projection end surface and the projection receiving surface, it is considered that the projection end surface and the projection receiving surface are in contact with each other as in the first embodiment.

  In addition, due to the viscosity of the grease 801, an appropriate movement resistance can be applied to the shift barrel 313 via the protrusions 313c and 321a. As a result, similarly to the first embodiment, it is possible to avoid a decrease in the controllability of the position of the shift barrel 313 through the vibration-proof actuator.

  In each of the embodiments described above, the case where the protrusions are provided at two places in the circumferential direction has been described. However, the place in the circumferential direction where the protrusions are provided is not limited thereto. For example, it may be one place or three or more places. However, when the shift barrel 313 moves relative to the main plates 301 (301 ′) and 312, the protrusions are arranged so that the shift barrel 313 does not rotate due to the viscosity of the grease 801, that is, to suppress the rotation. It is preferable to provide in multiple places.

  In each of the above embodiments, the case where the ball is provided at one place in the circumferential direction has been described. However, the ball may be provided at two or more places.

  In the first embodiment, the case where the projection 313 c is provided on the shift barrel 313 and the projection receiving recess 301 a is provided on the second base plate 301 has been described.

  However, as shown in FIG. 8, a cylindrical projection 301d may be provided on the second ground plane (first member) 301, and a projection receiving recess 313d may be provided on the shift barrel (second member) 313 ′. . Then, the grease 801 may be disposed inside the protrusion receiving recess 313d.

  Even in such a configuration, the same effect as in the first embodiment can be obtained.

  In the second embodiment, the case where the projections 313c and 321a are provided on the shift barrel 313 and the movement restricting member 321 and the protrusion receiving groove portions 321b and 301a 'are provided on the movement restricting member 321 and the second ground plate 301' has been described.

  However, as shown in FIG. 9, cylindrical protrusions 321d and 321a are provided on the surface of the movement limiting member 321 ′ on the side of the shift barrel 313 ″ and the surface of the second base plate 301 ′, respectively, so that the shift barrel 313 ″ is provided. In addition, the protrusion receiving groove portions 313d and 301a may be provided on the second ground plane 301 ′. The grease 801 may be disposed inside the protrusion receiving groove portions 313d and 301a.

  In this embodiment, when the shift barrel (the other member) 313 ″ is the second member, the movement limiting member 321 ′ is fixed to the second ground plane (one member) 301 ′ in the yaw direction. Further, when the second base plate (the other member) 301 ′ is the second member, the movement limiting member 321 ′ is connected to the shift barrel (one member) 313 ″ in the pitch direction. This corresponds to the first member fixed to the surface.

  Even in such a configuration, the same effect as in the second embodiment can be obtained.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment when the present invention is implemented.

  For example, in each of the above-described embodiments, the optical vibration isolator of the type in which the holding member is guided by the ball has been described. However, the present invention can also be applied to other types of optical vibration isolator. For example, the present invention can be applied to an optical image stabilizer that guides a holding member in a direction orthogonal to the optical axis direction by a guide bar.

  In each of the above embodiments, the optical image stabilization device mounted on the lens-integrated camera has been described. However, the optical image stabilization device of the present invention can also be mounted on an interchangeable lens as an optical device.

1 is an exploded perspective view of a shift unit mounted on a camera according to Embodiment 1 of the present invention. 1 is an external view of a camera according to Embodiment 1. FIG. 2 is an exploded perspective view of a lens barrel in the camera of Embodiment 1. FIG. Sectional drawing of the said lens-barrel. FIG. 3 is a partially enlarged view of the shift unit in the first embodiment. The disassembled perspective view of the shift unit mounted in the camera of Example 2 of this invention. FIG. 6 is a partially enlarged view of a shift unit in Embodiment 2. The elements on larger scale of the shift unit in Example 3 of this invention. The elements on larger scale of the shift unit in Example 4 of this invention.

Explanation of symbols

301 Second ground plate 301a Projection receiving recess 303 Magnet 308 Coil 313 Shift barrel 313c Projection 320 Ball 321 Movement limiting member 321b Projection reception recess 321a Projection 801 Grease

Claims (5)

A base member;
A holding member for holding the optical element;
An actuator for moving the holding member in a direction different from the optical axis direction with respect to the base member;
The first member, which is one of the base member and the holding member or a member fixed to the one member, is a member fixed to the other member or the other member. Having a protrusion protruding toward the member of 2,
An optical vibration isolator, wherein a viscous grease is disposed between the protrusion and the second member. The second member has a recess into which the protrusion is inserted,
The optical image stabilizer according to claim 1, wherein the grease is disposed inside the recess.   The protrusions are provided at a plurality of positions in the direction around the optical axis so as to suppress rotation of the holding member in the direction around the optical axis due to the viscosity when the holding member moves relative to the base member. The optical vibration isolator according to claim 1 or 2.   4. The optical image stabilizer according to claim 1, further comprising a ball that is disposed between the base member and the holding member and rolls with the movement of the holding member. 5. . An optical image stabilizer according to any one of claims 1 to 3,
And an optical system including the optical element.