JPH10319465A - Lens shifting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce driving resistance with a simple constitution and to shift a lens while keeping perpendicularity to an optical axis without backlash by supporting a movable member for holding the lens through a ball rotatable with respect to a reference plane surface perpendicular to the optical axis thereby preventing the turning around the optical axis of the movable member with an elastic member and pressing the movable member in an optical axial direction. SOLUTION: A movable frame 4 is supported in parallel with the reference plane surface 1b provided in a supporting frame 1 and being perpendicular to the optical axis, with three balls (steel balls) 2, without backlash in the optical axial direction, to attain shifting in a plane perpendicular to the optical axis 13. Therefore, optical performance is never degraded because of falling, the backlash, etc. The rolling friction of the balls 2 whose resistance is low is used to reduce shift driving force by electromagnetic drive. Further, the turning around the optical axis of the movable frame 4 is prevented by a pair of tension springs 6 facing each other and the pressing force of the movable frame 4 on the balls 2 is generated to prevent the backlash in the optical axial direction at the shifting time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a lens shift device for shifting a lens, such as a lens group held in a lens barrel, for decentering an optical axis in a plane perpendicular to the optical axis. is there.

[0002]

2. Description of the Related Art A mechanism for shifting a part of lenses of a lens group constituting a photographing lens in a direction perpendicular to an optical axis is used, for example, in a camera by detecting acceleration of camera shake which is a cause of image shake. The present invention can be applied to a vibration proof optical system that suppresses image blur by predicting blur and shifting the lens in a direction perpendicular to the optical axis based on the predicted signal.

[0003] As such a lens shift mechanism,
As disclosed in Japanese Patent Application Laid-Open No. 3-188430, camera shake is decomposed into a shake in a horizontal direction (hereinafter referred to as a yaw direction) and a shake in a vertical direction (hereinafter referred to as a pitch direction). Slide the shift lens for shake correction independently in the yaw and pitch directions, and without moving in the optical axis direction, by sliding with the guide bar and bearing in both the yaw and pitch directions, or by sliding. The surfaces of the plates and the like are configured to slide.

In Japanese Patent Application Laid-Open No. 63-155038,
The shift lens is held while restricting the rotation around the optical axis by the parallel four-bar link, and the movement in the optical axis direction by the parallel four-bar link is absorbed by the guide and the urging spring so as not to reach the shift lens. The spring is pressed against a reference plane with a ball interposed therebetween.

Further, in Japanese Patent Laid-Open No. Hei 5-297443, in addition to a member for restricting rotation of the shift lens around the optical axis,
At least three supporting points for balls and the like are provided between the support frame and the fixed frame of the shift lens, and are pressed by the pressurizing means so that the shift lens is shifted to be surely kept perpendicular to the optical axis. I have.

In Japanese Patent Application Laid-Open No. 7-294975, X
The shift lens is independently advanced and retracted by the feed screw in the axis (yaw) direction and the Y axis (pitch) direction, and a roller is interposed between the shift lens frame and the movable member so that the driving directions do not interfere with each other. It is possible to shift. Further, a ball is interposed between the shift lens frame and the base so as to prevent the shift lens from falling down at the time of shifting, and is configured to be urged by a spring.

[0007]

However, in Japanese Patent Application Laid-Open No. Hei 3-188430, the sliding resistance due to friction is large, and the energy required to drive the shift lens by electromagnetic force is large. In addition, there is an inconvenience that movement in the optical axis direction is strictly caused by minute play caused by fitting between the guide bar and the bearing.

In Japanese Patent Application Laid-Open No. 63-155038,
Since the lens barrel and the annular member are loosely fitted, rattling occurs in the direction perpendicular to the optical axis, albeit little. Further, when driving, sliding resistance occurs due to friction at the loose fitting portion, and the merit of a ball having low driving resistance as in a hinge portion of a link having low driving resistance is impaired. Further, the mechanism is complicated by the parallel four-bar links and the support provided by the balls, so that the number of parts is increased and the cost is increased. In addition, although only a one-way shift mechanism is disclosed, even if the mechanism is provided in a direction perpendicular to the above-described direction, the shift in an oblique direction can be simply performed due to the structure of the parallel four-bar link. There was an inconvenience that you couldn't.

In Japanese Patent Application Laid-Open No. 5-297443, the means for restricting the rotation of the shift lens around the optical axis is sliding by a fitting between a guide bar and a bearing or sliding by a slot and a pin. It cannot be said that the sliding resistance due to friction is sufficiently small, and in addition to the means for restricting the rotation of the shift lens around the optical axis, it has at least three balls and pressurizing means, which complicates the mechanism. However, there is a disadvantage that the number of parts is large and the cost is increased.

In Japanese Patent Application Laid-Open No. 7-294975, a sliding friction resistance generating portion is provided between a guide member of a movable member and a guide shaft, and a rolling friction resistance by a roller between the shift lens frame and the movable member is added. High resistance when driving the lens. In addition, a support mechanism using a ball is added to them, so that the mechanism is complicated, the number of parts is large, and the cost is increased.

(Aim of the Invention) A first object of the present invention is to provide a lens having a simple structure and having as little drive resistance as possible and capable of shifting the lens so as to be surely kept perpendicular to the optical axis without play. It is intended to provide a shift device.

A second object of the present invention is to provide a lens shift device which achieves the first object and can have a simpler structure.

A third object of the present invention is to provide a lens shift device which achieves the second object and can more reliably hold a ball.

[0014]

According to a first aspect of the present invention, a lens for decentering an optical axis and a fixing member having a reference plane perpendicular to the optical axis are provided. A movable member having a plane parallel to and opposed to the reference plane for holding the lens and shifting the lens in a plane perpendicular to the optical axis; and at least three movable members sandwiched between the two planes. Two rotatable balls, a holding member for holding the balls, and an elasticity for generating a pressing force for holding the balls between the two planes and for preventing the movable members from rotating around the optical axis. And a lens shift device having a member.

In the above construction, the movable member holding the lens is supported via a ball rotatable with respect to a reference plane perpendicular to the optical axis, and the elastic member prevents the movable member from rotating around the optical axis. In addition, the elastic member presses the movable member against the ball in the optical axis direction.

According to a second aspect of the present invention, there is provided a lens for decentering an optical axis, a fixing member having a reference plane perpendicular to the optical axis, and a lens parallel to the reference plane. And a movable member that holds the lens and shifts the lens in a plane perpendicular to the optical axis, and at least three rotatable balls sandwiched between the two planes. A ball holding portion for holding the ball, and a pressing force for holding the ball between the two planes, the movable member being provided integrally with the fixed member or the movable member; And a resilient member for preventing rotation about the optical axis.

In the above configuration, the ball holding portion is provided integrally with either the fixed member or the movable member.

According to a third aspect of the present invention, there is provided a lens for decentering an optical axis, a fixing member having a reference plane perpendicular to the optical axis, and a lens parallel to the reference plane. A movable member that holds the lens and shifts the correction lens in a plane perpendicular to the optical axis, and at least three rotatable balls sandwiched between the two planes. And a ball holding portion provided integrally with the fixed member or the movable member, having a concave portion having a depth greater than a radius of the ball, and holding the ball; and An elastic member that generates a pressing force sandwiched between flat surfaces and that prevents rotation of the movable member around the optical axis is provided.

In the above configuration, the depth of the simplified ball holding portion is made larger than the radius of the ball so that the ball can be held securely.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is an exploded perspective view showing the structure of a lens shift device according to a first embodiment of the present invention, and FIG. 2 is a sectional view of the lens shift device of FIG. 1 (corresponding to the AA section in FIG. 1). FIG. 3 is a perspective view showing a schematic configuration of a general anti-vibration system.

First, an image blur control system (anti-vibration system) using an angular displacement detecting device as a vibration sensor will be described.
This will be briefly described with reference to FIG.

FIG. 3 assumes an image stabilizing system that controls image shake caused by camera vertical shake 61p and camera horizontal shake 61y in the direction of the arrow 61 in the figure.

In the figure, reference numeral 62 denotes a lens barrel having a photographing optical system, 63p and 63y denote angular displacement detectors for detecting camera vertical shake angular displacement and camera lateral shake angular displacement, respectively. 64p, 64y. 65
p and 65y are operation circuits, and the angular displacement detection devices 63p and 65y
The signal from 63y is calculated and converted into a drive target signal for the correction lens shift mechanism. Then, the correction lens shift device 66 (67p, 67y is a drive unit thereof, and 68p, 68y is a shift position detection sensor of the correction lens) is driven by this signal to secure stability on the image plane 69.

The shift mechanism of the correction lens in FIGS. 1 and 2 will be described.

Reference numeral 1 denotes a support frame, which has a cylindrical outer peripheral surface 1a fitted to a lens barrel (not shown) and is supported so as to be movable only in the optical axis direction. Reference numeral 1b denotes a front end surface of the support frame 1, and an opening 1c through which a photographing light beam passes is provided at the center thereof.

Reference numeral 3 denotes a plate-shaped ball holding portion (a so-called retainer).
In the center, there is an opening 3b through which a photographing light beam passes, and three supporting balls (steel balls) 2 can be rotated around the opening 3b at substantially equal angular intervals of about 120 degrees. A hole 3a is provided for holding at a position including a center perpendicular to the optical axis and including a center of the two balls 2, and furthermore, a front vertex (most protruding portion) and a rear vertex (most protruding portion) of the three balls 2 in the optical axis direction. The projections form a plane perpendicular to the optical axis, and project from the front and rear surfaces of the ball holding unit 3 (see FIG. 2).
1 b is also a reference plane perpendicular to the optical axis, and is in contact with the ball 2.

In this embodiment, since the three balls have the same diameter, the reference plane 1b (see FIG. 2) is located in the same plane. If the balls have different diameters, the reference plane 1b forms a plurality of different planes.

Reference numeral 4 denotes a movable frame having a central opening 4a for holding the correction lens 5, and a rear surface having a plane 4b which is in contact with the ball 2 and is parallel to the reference plane 1b and opposed to the reference plane 1b. The plane 4b has a margin of contact with the ball 2 within the shift range of the lens.

In this embodiment, since the apexes (most protruding portions) on the front side in the optical axis direction of the three balls form a plane perpendicular to the optical axis, the plane 4b is the same plane. If the vertices on the front side in the optical axis direction of the three balls do not form a plane perpendicular to the optical axis, and the vertices on the front side in the optical axis direction are different, the plane 4b is located on the front side in the optical axis direction of each ball. There are a plurality of different planes perpendicular to the optical axis according to the vertex positions. Also in this case, naturally, each plane 4b is formed with a margin in the contact range with the ball 2 within the shift range of the lens.

Reference numeral 6 denotes an elastic member which is a tension coil spring. A spring hook hole having one end on the rear side provided on a spring hook projection 1e of the support frame 1 and one end on the front side provided on an end of the movable frame 4 in a stretched state. 4c, the movable frame 4 is pulled obliquely backward to the outside with respect to the optical axis.

A pair of such elastic members 6 as tension coil springs are provided so as to face each other by 180 degrees. The movable frame 4 has the optical axis of the correction lens 5 coincident with the optical axis of the lens barrel. It is urged with almost the minimum necessary force to return the surrounding rotation to the original position. Further, a minimum necessary pressing force for holding the ball between the back surface 4b of the movable frame 4 and the reference surface 1b of the support frame 1 is generated.

7p is a pitch magnet, 8p is a pitch yoke, and both 7p and 8p are upper central concave portions 1 of the support frame 1.
fixed to p. 9p is a pitch coil, movable frame 4
Is fixed to the center of the upper end. 7y is a yaw magnet, 8y is a yaw yoke, and both 7y and 8y are support frames 1.
Is fixed to the lateral central recess 1y.

Reference numeral 9y denotes a yaw coil, which is fixed to the center of the lateral end of the movable frame 4. 10 is a front yoke for pitch,
It is formed of one part in common for yaw, and is inserted through three holes 10 a by screws 11, and is provided with three mounting arms 3 of the ball holding part 3 on three female screw protrusions 1 f of the support frame 1.
Fixed with c.

The coils 9p and 9y are provided with a magnet 7
It has a slight air gap between p, 7y and yoke 10, is placed in a magnetic circuit formed by a magnet and a yoke, and moves movable frame 4 in the pitch direction by flowing a current through coil 9p. The movable frame 4 is driven in the yaw direction by passing a current through the coil 9y.

The movable frame 4 has a pitch slit 12p.
And a yaw slit 12y, and a pitch slit 12
The pitch direction of the movable frame 4 and the yaw of the yaw slit 12y correspond to the light emitting element (infrared light emitting diode (IRED)) and the light receiving element (semiconductor position detecting element (PSD)) (not shown) corresponding to the p and the yaw slit 12y, respectively. Direction position detection is performed. 13 is an optical axis.

In the above configuration, the movable frame 4 is supported in parallel with the reference plane 1b provided on the support frame 1 perpendicular to the optical axis via the ball (steel ball) 2 without play in the optical axis direction. , Also on a plane perpendicular to the optical axis 13.

Accordingly, the optical performance does not deteriorate due to falling or backlash. In addition, since the rolling friction of the ball (steel ball) 2 having extremely low resistance to the frictional resistance due to the sliding of the shaft and the bearing is used, the shift driving force by the electromagnetic drive can be reduced. Further, only the elastic member 6, which is a pair of opposed tension coil springs, prevents the movable frame 4 from rotating around the optical axis, generates a pressing force of the movable frame 4 against the ball, and generates the pressing force of the optical axis during shifting. The play in the direction can be prevented.

That is, with the simple configuration as described above, the shift driving force of the correction lens supported by the movable frame can be reduced, and the optical performance is not degraded due to the tilting of the optical axis and the play due to the shift. High precision shift lens position control that can be driven finely is also supported. In addition, if the shift lens control with extremely high precision is not pursued, the drive unit due to the electromagnetic force or the like can be reduced, and the shift mechanism can be downsized and energy can be saved. Further, there is an effect of cost reduction by reducing the number of parts by a simple configuration and the number of assembling steps.

(Second Embodiment) FIG. 4 is an exploded perspective view showing a structure of a lens shift device according to a second embodiment of the present invention, and FIG. 5 is a sectional view (FIG. 5) of the lens shift device of FIG. 4
BB), and the schematic configuration of the anti-vibration system is the same as that in FIG.

The same parts as those in the first embodiment are denoted by reference numerals obtained by adding 100 to the reference numerals in the first embodiment.

The shift mechanism of the correction lens in FIGS. 4 and 5 will be described.

A support frame 101 has a cylindrical outer peripheral surface 101a fitted to a lens barrel (not shown) and is supported so as to be movable only in the optical axis direction. Reference numeral 101b denotes a front end surface of the support frame 101, and an opening 101 through which a photographing light beam passes is provided at the center thereof.
c are provided, and three supporting balls (steel balls) 102 are rotatable substantially evenly around the opening 101c at an angular interval of about 120 degrees, and the apexes of the three balls on the optical axis front side ( The ball holding portion 1 which forms a plane perpendicular to the optical axis so as to protrude from the front end face 101b.
03 is provided integrally with the support frame 101 (see FIG. 5).

Reference numeral 101d denotes a reference plane perpendicular to the optical axis (see FIG. 5).
It is formed in the back of. In this embodiment, since three balls have the same diameter, three reference planes 101d
Are located in the same plane. If the ball diameters are different, each reference plane 101d forms a different plane. The depth of the ball holding portion 103 is larger than the radius of the ball 102, and the ball 102 is
It is held so that it can rotate reliably without jumping over 03a.

Reference numeral 104 denotes a movable frame.
5 has an opening 104a for holding the ball 1
02 and a plane 104b that is in parallel with and opposed to the reference plane 101d. The plane 104b has a contact area with the ball 102 within the shift range of the lens with a margin.

In this embodiment, the front vertices (most protruding portions) of the three balls in the optical axis direction form a plane perpendicular to the optical axis, so that the plane 104b is the same plane. If the vertices on the front side in the optical axis direction of the three balls do not form a plane perpendicular to the optical axis, and the vertices on the front side in the optical axis direction are different, the plane 104b is the front side on the optical axis direction of each ball. There are a plurality of different planes perpendicular to the optical axis according to the vertex positions. In this case as well, each plane 104b is formed with a margin in the contact range with the ball 102 within the shift range of the lens.

Reference numeral 106 denotes an elastic member which is a tension coil spring. A spring hook hole provided with a rear end on a spring hook projection 101e of the support frame 101 and a front end on an end of the movable frame 104 in a stretched state. The movable frame 104 is hung on each of the movable frames 104c, and is pulled obliquely backward to the outside with respect to the optical axis. A pair of such elastic members 106, which are tension coil springs, are provided so as to face each other by 180 degrees, and the movable frame 104 has the optical axis of the correction lens 105 coincident with the optical axis of the lens barrel. Is pressed with almost the minimum necessary force to return to the original position. Further, the back surface 104b of the movable frame 104 and the support frame 101
A substantially necessary minimum pressing force for holding the ball between the reference surface 101d and the reference surface 101d is generated.

Reference numeral 107p denotes a pitch magnet, 108p denotes a pitch yoke, and both 107p and 108p support frame 1
01 is fixed to the upper central concave portion 101p. 109
p is a pitch coil, which is fixed to the center of the upper end of the movable frame 104. 107y is a yaw magnet, 108y is a yaw yoke, and both 107y and 108y support frame 101.
Is fixed to the lateral center concave portion 101y.

A yaw coil 109y is fixed to the center of the lateral end of the movable frame 104. 110 is a front yoke,
It is composed of one component for pitch and yaw, and is penetrated through three holes 110a by the pis 111, and the support frame 1
01 are fixed to three internal thread bosses 101f.

The coils 109p and 109y have a slight air gap between the magnets 107p and 107y and the yoke 110, are placed in a magnetic circuit formed by the magnet and the yoke, and apply a current to the coil 109p. By flowing, the movable frame 104 is driven in the pitch direction,
The movable frame 104 is driven in the yaw direction by passing a current through the coil 109y. The movable frame 104 is provided with a pitch slit 112p and a yaw slit 112y, and a light emitting element (not shown) (infrared light emitting diode (IRE)) corresponding to the pitch slit 112p and the yaw slit 112y.
D)) and a light receiving element (semiconductor position detecting element (PS
In relation to D)), the positions of the movable frame 104 in the pitch direction and the yaw direction are detected. 113 is an optical axis.

In the above configuration, the movable frame 104 is supported in parallel with the reference plane 101d provided on the support frame 101 and perpendicular to the optical axis via the ball (steel ball) 102 without play in the optical axis direction. , Also on a plane perpendicular to the optical axis. Therefore, the optical performance is not degraded due to the fall or the backlash. Moreover, since the rolling friction of the ball (steel ball) 102 having extremely low resistance to the frictional resistance due to the sliding of the shaft and the bearing is used, the shift driving force by the electromagnetic drive can be reduced.

Further, the rotation of the movable frame 104 around the optical axis is prevented by only the elastic member 106, which is a pair of opposed tension coil springs. The play in the optical axis direction can be prevented.

In the second embodiment, since the ball holding portion 103 is provided integrally with the support frame 101, in addition to the effects of the first embodiment, the ball holding portion is not required as a separate component. The configuration is simpler, and the cost reduction effect is great.

Since the depth of the ball holding portion 103 is larger than the radius of the ball 102, the ball 102 does not jump over the side wall 103a of the ball holding portion.
The ball 102 can be surely rotated.

(Correspondence between the Invention and the Embodiment) In each of the above embodiments, the correction lenses 5 and 105 are used for the shifting lens of the present invention, the support frames 1 and 101 are used for the fixed member of the present invention, Reference numeral 104 corresponds to the movable member of the present invention, and the elastic members 6 and 106 formed of tension coil springs correspond to the elastic members of the present invention.

The correspondence between the components of the embodiment and the components of the present invention has been described above. However, the present invention is not limited to the configuration of the embodiment, and the functions and features described in the claims can be obtained.
Needless to say, any configuration may be used as long as the functions of the embodiment can be achieved.

(Modification) In the first and second embodiments, three balls 2 (102) are provided.
The present invention is not limited to this, and three or more pieces may be used.

In the second embodiment, the ball holding section 103 is provided integrally with the support frame 101, but may be provided on the movable frame 104.

In the first and second embodiments, the elastic member is a pair of opposed tension coil springs, but three or more tension coil springs may have the same function. The elastic member is not limited to the tension coil spring, but may be configured to obtain the same effect by using an urging spring.

[0060]

As described above, according to the present invention,
A movable member for holding the lens is supported via a ball rotatable with respect to a reference plane perpendicular to the optical axis, and rotation of the movable member around the optical axis is prevented by the elastic member. Since the ball is pressed in the optical axis direction, the driving resistance can be reduced as much as possible with a simple configuration, and the lens can be shifted so as to be surely kept perpendicular to the optical axis without play.

According to the present invention, the ball holding portion is
Since it is provided integrally with either the fixed member or the movable member, a lens shift device having a simpler configuration can be provided.

Further, according to the present invention, the depth of the ball holding portion is set to be larger than the radius of the ball, so that the ball can be held more reliably.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a structure of a lens shift device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a perspective view showing a schematic configuration of a general anti-vibration system.

FIG. 4 is an exploded perspective view showing a structure of a lens shift device according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 101 Support frame 1b, 101d Reference plane 2, 102 Ball (steel ball) 3, 103 Ball holder 4, 104 Movable frame 4b, 104b Opposing plane of movable frame 5, 105 Correction lens 6, 106 Elastic member

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[Procedure amendment]

[Submission date] June 27, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a structure of a lens shift device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a perspective view showing a schematic configuration of a general anti-vibration system.

FIG. 4 is an exploded perspective view showing a structure of a lens shift device according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

[Description of Signs] 1,101 Support frame 1b, 101d Reference plane 2,102 Ball (steel ball) 3,103 Ball holding part 4,104 Movable frame 4b, 104b Opposing plane of movable frame 5,105 Correction lens 6, 106 elastic member

Claims (3)

[Claims] 1. A lens for decentering an optical axis, a fixing member having a reference plane perpendicular to the optical axis, and a plane parallel to and opposed to the reference plane for holding the lens and mounting the lens. A movable member that shifts in a plane perpendicular to the optical axis, at least three rotatable balls sandwiched between the two planes, a holding member for holding the ball, and the two balls An elastic member for generating a pressing force to be sandwiched between the planes and for preventing the movable member from rotating around the optical axis. 2. A lens for decentering an optical axis, a fixing member having a reference plane perpendicular to the optical axis, and a plane parallel to and opposed to the reference plane for holding the lens and mounting the lens. A movable member for shifting in a plane perpendicular to the optical axis, at least three rotatable balls sandwiched between the two planes, and provided integrally with either the fixed member or the movable member, A ball holding portion for holding the ball; and an elastic member that generates a pressing force for holding the ball between the two planes and that prevents rotation of the movable member around the optical axis. Lens shift device. 3. A lens for decentering an optical axis, a fixing member having a reference plane perpendicular to the optical axis, and a plane parallel to and opposed to the reference plane for holding the lens and correcting the lens. A movable member for shifting in a plane perpendicular to the optical axis, at least three rotatable balls sandwiched between the two planes, and provided integrally with either the fixed member or the movable member, A concave portion having a depth greater than a radius of the ball, a ball holding portion for holding the ball, and a pressing force for clamping the ball between the two planes; A lens shift device comprising: an elastic member that prevents rotation around an axis.