JPH03186823A - Image stabilization device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention is directed to an anti-vibration device disposed in a camera, etc., which detects relatively low-frequency vibrations and uses this information as information for preventing image blur. In particular, the present invention relates to improvements in the correction optical mechanism thereof.

(Background of the Invention) The conventional technology to which the present invention is applied will be explained below using a camera as an example.

In modern cameras, all important tasks for photography, such as exposure determination and focus adjustment, are automated, so even those who are inexperienced in operating the camera are less likely to make a mistake in taking a picture. Shooting failures cannot be automatically prevented. Therefore, in recent years, research has been carried out on cameras that can prevent photographing failures caused by camera shake, and in particular, research and development are progressing on cameras that can prevent photographing failures due to camera shake.

The above-mentioned camera shake usually has a vibration frequency of IHz to 12Hz, but in order to be able to take a picture without image blur even if such camera shake occurs at the time of shutter release, it is necessary to reduce the above-mentioned camera shake. It is necessary to detect the vibration of the camera due to the vibration of the camera, and to displace the correction lens according to the detected value.

Therefore, in order to achieve the above purpose (i.e., to be able to take photographs that do not cause image blur even when camera shake occurs), it is necessary to accurately detect camera vibration and compensate for changes in the optical axis due to camera shake. Is required.

In principle, the prevention of camera shake mentioned above is based on angular acceleration,
This is done by equipping the camera with a vibration sensor that detects angular velocity, etc., a camera shake detection system that electrically or mechanically integrates the signal from the sensor and outputs angular displacement, and a correction optical mechanism that decenters the optical axis. be able to.

Here, an outline of the image pre-suppression system using an angular velocity meter will be explained using FIG. 3.

FIG. 3 shows an example of a system for suppressing vertical camera shake 31p and horizontal camera shake 31y in the direction of arrow 31, and in the figure, 32 denotes a lens barrel, 33p, 33. y
are angular velocity meters that detect the camera vertical angular velocity and camera horizontal angular velocity, and the angular velocity detection directions are 34p and 3, respectively.
It is shown as 4y. 35p and 3sy are known analog integration circuits which integrate the signals from the angular velocity meters 33p and 33y and convert them into a hand movement angular displacement. 36 is a correction optical system that is driven based on the signal and ensures stability on the image plane 39 (37p, 373/ are the driving parts, 3sp, 38y, respectively)
is a corrected optical position detection sensor). Incidentally, it is also possible to provide the correction optical mechanism itself with a mechanical integration function and omit the above-mentioned analog integration circuit.

FIGS. 4(a) and 4(b) are structural diagrams of a correction optical mechanism suitably used in an anti-shake camera, and the configuration thereof is shown below.

In addition, FIG. 4(b) is represented by the AA cross section of FIG. 4(a), and FIG. 4(a) shows the stator 220 on the left side of the figure shown in FIG. 4(b), and The projector 213 and pitch magnet 29 are omitted to avoid complicating the drawing.

Note that the correction optical mechanism operates in two mutually orthogonal directions (pitch and yaw: arrows 21p and 21y in Fig. 4(a)).
direction), but the configuration is similar in both directions,
First, only the pitch direction (2ip) will be explained.

In FIG. 4, a fixed frame 23 holding the correction lens 22
can slide on a pitch shaft 25 via an oilless metal 24 (partially shown in cross section) which is a sliding bearing. Further, the pitch shaft 25 is connected to the first holding frame 2
It is attached to 6. The fixed frame 23 is the pitch shaft 2
It is held between pitch coil springs 27 coaxial with 5 and held at a neutral position. The fixed frame 23 has a pitch coil 28 (
(partially shown in cross section) is the installation. Pitch coil 28
is placed in a magnetic circuit configured as shown by a dotted line 211 with a pitch magnet 29 attached to the first holding frame 26 and a pitch yoke 210, and by passing current through this, the fixed frame 23 Pitch direction 2 with respect to the holding frame 26 of
Driven to 1p.

The pitch coil 28 is provided with a slit 212p, and a floodlight 213 (infrared light emitting diode IRED)
The position of the fixed frame 23 relative to the first holding frame 26 in the pitch direction 21p is detected by the relationship between the fixed frame 23 and the light receiver 214 (semiconductor device detection element PSD).

The first holding frame 26 includes a yaw shaft 215 extending in one direction 21y and a housing 217 containing an oil-less metal (sliding bearing) that slides on the yaw shaft 215.
The housing 217 has a yaw shaft 215
It is held in a neutral state by being sandwiched between a yaw coil spring 218 coaxial with the yaw coil spring 218. Since the housing 217 is attached to the second holding frame 219, the first holding frame 26 is attached to the second holding frame 219.
It is freely movable in one direction 21y with respect to the holding frame 219. The first holding frame 26 is provided with a yaw coil 221 in the same way as the fixed frame 23, and the yaw coil 221 is connected to a yaw yoke 222 attached to the second holding frame 219 and a yoke 223 between the yaw yoke 222 and the collar 223. Yaw magnet 2 attached to stem 220 fixed apart from each other
24 (not shown), and by passing a current through this, the first holding frame 26 becomes the second holding frame 2.
19, it is driven in one direction 21y. The yaw coil 22] is provided with a slit 225, which allows the projector (not shown) attached to the second holding frame 219 and the stator 2
The position of the first holding frame 26 relative to the second holding frame 2] and 9 in one direction 21 and y is detected by a light receiver (not shown) attached to the holding frame 20.

It is necessary for the correction optical mechanism configured as described above to operate faithfully to the signal from the integrating circuit within the camera shake band of 1 to 12) 1z, but it must operate faithfully within the band required for Mt. In order to achieve this, it is necessary to follow the band one order of magnitude higher than that, and therefore, in this case, a correction optical mechanism that also responds to signals with a frequency of 120 Hz or higher is required.

To achieve this, the parts that are driven must be made as light as possible.

However, the fixed frame 2 is not attached to the correction lens 22 which is the driven part.
3. Although only the pitch coil 28 is attached, the first holding frame 26, which is also a driven part, is attached to the correction lens 22.
, the fixed frame 23, the pitch coil 28, and its own weight (the first holding frame 26, the yaw coil 22]), as well as the pitch magnet 29, the pitch yoke 210, the emitter 2]3, and the receiver 214 are attached. Since the magnet 29 and the pitch yoke 210 have large masses, the driven part becomes quite heavy, and it is extremely difficult to make it respond to high frequency signals.

Therefore, in order to reduce the weight of the driven part, some ideas have been made to make the drive source completely independent of the correction optical system.

FIG. 5 is a diagram explaining this, in which the fixed frame 23 holding the correction lens 22 is connected to the pitch parallel link 2.
The first holding frame 26 is accessed through 3 bp. Therefore, the fixed frame 23 is movable relative to the first holding frame 26 in the pitch direction 2 ], p.叉、first
The holding frame 26 is attached to the second holding frame 219 via a parallel link 235y, and can be moved 1 J relative to the second holding frame 219 in one direction 21y. Since the second holding frame 2]9 is fixed to a lens barrel (not shown), the correction lens 22 is 2]p, 2 with respect to the lens barrel.
It is movable in the 1y direction. In addition, there is a base 2 on the lens barrel.
30p, 230y and coreless motor 231p,
23], y is attached. The core 1 smoke 23] p, 231y has cams 232p, 232y (2
32y (not shown) are attached, and the fixed frame 23 and the first
(The intermediate plate 233 and the ball bearing 234 have the role of eliminating friction between the cam 232p and the fixed frame 23).

Then, the coreless motors 23]p and 231y rotate,
When the cams 232p and 232y lift, each of the four fixed frames 23
, to push the second holding frame 26, the correction lens 22 is driven in the pitch direction 21p and the B direction 21y.

Also, cams 232p, 232. Spring 2 is attached to the part where Y is engraved.
36p and 236y are attached, and since these always push the cams 231p and 231y, the coreless motor 23]
, p, 23 +, y rotate in the opposite direction, and the cams 232p, 2
As the height of the peak 32y decreases, the correction lens 22 is driven in the opposite direction.

With this structure, the coreless motors 231p and 231y, which are drive sources, are attached to the lens barrel, so the weight of the driven part can be reduced. However, cam 2
32p, 232y and the fixed frame 23 and the second holding frame 26 require means for eliminating friction, that is, an intermediate plate 233 and a ball bearing 234. In particular, the ball bearing 234 is expensive and requires space for personnel. 1, and
Especially in the case of such a configuration, a spring 236Pp is connected between the cams 232p, 232y0, the fixed frame 23, and the first holding frame 26.
, 236y are used to eliminate backlash, and therefore movements exceeding the resonance frequency of these springs cannot be followed. Therefore, it is possible to increase the force of these springs, but there is a limit to the power of the coreless motors 231p and 231y, and from the viewpoint of power consumption, it is not possible to increase the spring force, so the structure shown in FIG. Although the weight of the driven part could be reduced, there was a limit to high-speed tracking ability.

(Objective of the Invention) The object of the present invention is to solve the above-mentioned problems and provide a vibration isolating device that can respond to high frequency vibrations without increasing costs or requiring a large space. be.

(Characteristics of the Invention) In order to achieve the above object, the present invention provides first and second magnetic field generating members and first and second magnetic field generating members. At least one of the second position detection means is provided on a fixing member that is fixed to the lens barrel and includes a second holding frame, so that at least one of the second position detection means is provided on a fixing member that is fixed to the lens barrel and includes a second holding frame. The second magnetic field generating member and the first magnetic field generating member. Both or one of the second position inspection means is not arranged on the first holding frame which is the driven part, thereby reducing the weight of the driven part. shall be.

(Embodiments of the Invention) Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIGS. 1(a) and 1(b) are diagrams showing the structure of a correction optical mechanism that is an embodiment of the present invention. Note that FIG. 1(b) shows a cross section taken along the line B-B, which is above the optical axis in FIG. 1(a), and shows a side view below the optical axis from the direction C. Also, in FIG. 1(a), the stator 220, the projector 213, and the pitch magnet 29 on the left side of the figure shown in FIG. 1(b) are shown in FIG.
is omitted to avoid complicating the drawing.

This embodiment differs from the conventional example shown in FIGS. 4(a) and 4(b) described above in that the pitch magnet 29 and pitch yoke 210 that sandwich the pitch coil 28 are removed from the first holding frame 26, and the pitch magnet 29 is removed from the first holding frame 26. The stator 220 and the pitch yoke 210 are attached to the second holding frame 219, respectively. The emitter 213, stator 220, and light receiver 214 attached thereto are also attached to the second holding frame 219.
Each is installed. Other parts are shown in Figure 4(a)
Since this is the same as (b), the explanation will be omitted.

Here, the fixed frame 23 has a first holding frame 26 in the yaw direction 21.
As it moves in the y direction, it also moves in the y direction 21y, so the positions between the pitch coil 28, the pitch yoke 210, and the pitch magnet 29 shift. However, the direction 21 of the pitch magnet 210 and the pitch yoke 210 is
Since the length I2y of y satisfies the following formula, even if the first holding frame 26 is moved to the farthest direction 21y, the length of the thrust generating portion in the magnetic circuit does not change, and the pitch of the fixed frame 23 is direction 2
No fluctuation occurs in the thrust of the coil 28 that is driven to 1p. In the formula below, 4c is the pitch direction 2 of the pitch coil 28.
The thrust generating part that drives toward 1p, sy, is the first holding frame 26
is the maximum stroke of

1; lc +Sy<βy Similarly, the slit 212 provided in the fixed frame 23 extends long in the y direction 21y, and when the first holding frame 26 is neutral in the y direction 21y, as shown in FIG. With the relationship between the slit 212, the emitter 213, and the receiver 214 as shown in (a), the movement of the slit 212 in the pitch direction 21p (movement of the fixed frame 23 in the pitch direction 21p) is detected,
When the first holding frame 26 is at the extreme end in one direction 213/, the second holding frame 26
The relationship is as shown in Figure (b), and even in this case, the fixed frame 2
3 in the pitch direction 21p can be detected well.

According to this embodiment, the magnets 29, 224 and the yoke 210, which were conventionally attached to the first holding frame 26,
, 222 and position detection means, etc., are fixed to the fixed parts (in the embodiment, the stator 220 and the second holding frame 219).
Since it is attached to the
The weight of the holding frame 26 is reduced, making it possible to provide a vibration isolating device that can accurately track up to high frequencies.

(Correspondence between the invention and the embodiment) 4 In this embodiment, the magnets 29, 224, the yoke 2
10.222 is the first example of the present invention. In the second magnetic field generating member,
The light projector 213 and the light receiver 214 are connected to the first position detection means (the second position detection means is not shown), the second holding frame 219,
The stator 220 corresponds to a fixed member.

(Effects of the Invention) As explained above, according to the present invention, the first and second magnetic field generating members, the first and second magnetic field generating members, and the first and second magnetic field generating members. At least one of the second position detection means is provided on a fixing member that is fixed to the lens barrel and includes a second holding frame, so that at least one of the second position detection means is provided on a fixing member that is fixed to the lens barrel and includes a second holding frame. The second magnetic field generating member and the first magnetic field generating member. Both or one of the second position detection means is not arranged on the fixed frame and the first holding frame, which are the driven parts, to reduce the weight of the driven parts. , it becomes possible to respond to high-frequency vibrations without increasing costs or requiring a large space.

[Brief explanation of drawings]

5. FIG. 1(a) is a plan view showing one embodiment of the present invention, 5. FIG. 1(b) is a BB cross section and a side view in the C direction, and
The figures are a diagram showing the relationship between the slit shown in Figure 1 and the position detection means, Figure 3 is a perspective view showing a state in which a conventional example mechanism is incorporated into a camera, and Figure 4 (a) is another example of the conventional mechanism. 4(b) is a plan view showing details of the correction optical mechanism of
The sectional view and FIG. 5 are perspective views showing yet another conventional correction optical mechanism. 22... Correction lens, 23... Fixed frame, 26... First holding frame, 28, 221...
... Coil, 210.222 ... Yoke, 2
9,224...Magnet, 220...
・Stator, 213... Floodlight, 214...
... Light receiver, 219 ... Second holding frame.

Claims (1)

[Claims] (1) A correction optical mechanism disposed within a lens barrel holding a lens group and decentering the optical axis of the lens group; a vibration detection means for detecting vibrations applied to the lens barrel; In the camera image stabilization device, the camera image stabilization device includes an image stabilization control means that drives the correction optical mechanism based on a signal from the camera and performs image stabilization. a first holding frame that holds the fixed frame movably in a first direction different from the optical axis direction of the lens group; and a first holding frame that holds the fixed frame movably in a first direction different from the optical axis direction of the lens group; a second holding frame fixed to the lens barrel, which is held movably in second directions different from the second holding frame; and moving the first and second holding frames in the first and second directions, respectively. first and second driving means comprising first and second coils and first and second magnetic field generating members facing the first and second coils; the fixed frame; 1st holding frame
, comprising first and second position detecting means for detecting the amount of movement in the second direction, wherein the first and second magnetic field generating members and the first and second position detecting means are connected to each other. A vibration isolating device characterized in that at least one of them is provided on a fixing member that is fixed to the lens barrel and includes the second holding frame.