JPH086088A - Anti-shake device - Google Patents

Abstract

PURPOSE:To reduce current consumption at the time of driving a shake preventing optical system by shortening time required for the centering processing of the shake preventing optical system. CONSTITUTION:This shake preventing device is provided with a main optical system, the shake preventing optical system 10 for preventing shake caused by vibration and supporting members 11 elastically supporting the shake preventing optical system 10 so as to move it in a direction nearly perpendicular to the optical axis of the main optical system and the optical system 10 is attached in a position where the optical center is deviated from the optical axis of the main optical system, when the deflections of the supporting members 11 are about zero based on the settlement by the dead weight of a part including the optical system 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shake prevention device for preventing image shake due to camera shake in a camera, for example.

[0002]

2. Description of the Related Art As a conventional anti-shake device of this type, a part of the taking lens (hereinafter referred to as "anti-vibration lens") is provided in order to prevent the shake caused by the vibration of the camera during photographing. It is known to move in a direction substantially perpendicular to the optical axis. For example, Japanese Patent Laid-Open No. 2-66536
In the one disclosed in the publication, the vibration-proof lens is supported by a flexible support rod. And the anti-vibration lens
It is moved by an electromagnetic actuator. With such an anti-vibration lens supporting method, a complicated and expensive slide structure and a driving mechanism for moving the anti-vibration lens in a direction substantially perpendicular to the optical axis are not required, and the anti-vibration device is lightweight, The size can be reduced.

[0003]

However, the above-described conventional shake prevention device has the following problems. The most shooting posture is when the camera lens is oriented horizontally with respect to the ground, that is, when the shake prevention device is arranged so that the optical axis of the main optical system is substantially perpendicular to the vertical direction. . At this time, the support rod is bent by the weight of the portion including the anti-vibration lens, and the optical center of the anti-vibration lens is displaced from the optical axis of the main optical system. On the other hand, when performing the exposure process, the anti-vibration lens is moved after performing the centering process of the anti-vibration lens. However, when the optical center of the anti-vibration lens and the optical axis of the main optical system are largely deviated, this centering is performed. There is a problem in that the time required for processing becomes long and the current consumption increases.

The present invention has been made to solve the above problems, and shortens the time required for the centering process of the shake preventing optical system and reduces the current consumption during driving of the shake preventing optical system. The purpose is to do.

[0005]

In order to achieve the above object, the first solution means of the shake prevention apparatus according to the present invention is
Main optical system, shake prevention optical system for preventing shake generated by vibration, and support for elastically supporting the shake preventing optical system so as to be movable in a direction substantially perpendicular to the optical axis of the main optical system. A shake prevention device comprising a member, wherein the shake prevention optical system has an optical center when a deflection amount of the support member is substantially 0 based on a subsidence amount of a portion including the shake prevention optical system due to its own weight. Is attached at a position deviated from the optical axis of the main optical system.

A second solving means is the same as the first solving means, when the shake preventing optical system is arranged so that the optical axis of the main optical system is oriented in a direction substantially perpendicular to the vertical direction. The optical axis is set so that its optical center substantially coincides with the optical axis of the main optical system by sinking due to its own weight of the portion including the shake preventing optical system.

A third solving means is that the main optical system, a shake preventing optical system for preventing shake generated by vibration, and the shake preventing optical system are substantially perpendicular to the optical axis of the main optical system. In a shake prevention device comprising a support member elastically supported so as to be movable in various directions, the shake prevention optical system is based on a subsidence amount due to its own weight of a portion including the shake prevention optical system,
When the deflection amount of the support member is substantially zero, the optical center is attached at a position displaced from the center of the movable range.

A fourth solving means is the third solving means, wherein the shake prevention optical system is arranged so that the optical axis of the main optical system is oriented in a direction substantially perpendicular to the vertical direction. The optical axis is set so that its optical center substantially coincides with the center of its movable range by sinking due to its own weight of the portion including the shake prevention optical system.

[0009]

In the first solving means, the shake preventing optical system is previously attached at a position displaced from the optical axis of the main optical system. During normal shooting, the shake-preventing optical system sinks due to its own weight, so that the optical center of the shake-preventing optical system comes close to the optical axis of the main optical system. In the second solution, when the optical axis of the main optical system, which is the most shooting posture, is arranged substantially parallel to the ground, the optical center of the shake prevention optical system and the optical axis of the main optical system are Will almost match.

In the third solving means, the shake preventing optical system is attached in advance at a position deviated from the center of its driving range. During normal shooting, the shake-preventing optical system sinks due to its own weight, and the optical center of the shake-preventing optical system comes closer to the center of its drive range.
In the fourth solution, when the optical axis of the main optical system is arranged substantially parallel to the ground, the optical center of the shake prevention optical system and the center of its driving range substantially coincide with each other to prevent shake. The movable range of the optical system becomes the widest.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of an embodiment of the shake prevention apparatus according to the present invention. In FIG.
(A) shows a front view, (b) shows a side view. Also,
FIG. 2 is a diagram showing an electromagnetic actuator that drives the image stabilizing lens 10 of FIG.

In FIG. 2, the magnet 12 is magnetized to have two poles. The coil 14 is wound around a direction parallel to the optical axis and is arranged near the magnet 12. The yokes 13 and 15 are made of a material such as iron. The yoke 13 is provided so as to face the magnet 12 via the coil 14, and the yoke 15 is attached to the magnet 12. In this electromagnetic actuator, the magnet 12, the coil 14, and the yokes 13 and 15 form a magnetic circuit having magnetic lines of force in the direction of the arrow in the figure. Here, when an electric current is applied to the coil 14, an electromagnetic force is generated according to Fleming's left-hand rule in a direction perpendicular to the direction of current flow and the direction of magnetic force lines. Therefore,
In FIG. 1, when the coil 14a is energized, a force in the X-axis direction is generated. Similarly, when the coil 14b is energized, Y
Axial force is generated.

A lens barrel 21 for holding the anti-vibration lens 10
Is cantilevered at the tips of four support rods 11 made of an elastic body having the same length. Therefore, as shown in FIG. 3, the lens barrel 21 changes from the state (a) to the state (b).
Can move in a direction substantially perpendicular to the optical axis. At this time, the support rod 11 is elastically deformed.

In FIG. 1, LEDs 17a and 17b (which may be infrared emitting LEDs) which are light emitting elements (in FIG. 1,
(Only the LED 17a can be seen) is attached to the top plate 19, and the PSDs 18a, 1
8b is attached to the bottom plate 20. The slit portions 16a and 16b for detecting the X-axis and Y-axis directions are the lens barrel 2
Mounted on the LED 1 and arranged between the LEDs 17a and 17b and the PSDs 18a and 18b, respectively.
Slits 16a-1 and 16b extending in the axial and X-axis directions
-1. The light emitted from the LED 17 passes through the slit 16-1 and enters the PSD 18. That is, the operation of the slit 16-1 (operation of the image stabilizing lens 10)
Becomes the movement of the light incident on the PSD 18, and PSD1
It is output as a current from 8.

FIG. 4 is a block diagram showing an embodiment of the shake prevention processing. When the camera causes a pitching motion or a yawing motion, the optical axis is relatively moved, and the image on the film surface moves. Therefore, in order to relatively cancel the movement of the optical axis, the vibration proof lens 10 is moved so as to stop the movement of the image on the film surface. Here, the movable range of the anti-vibration lens 10 is determined by the movable limiter 20 a (FIG. 1) raised from the bottom plate 20.

First, the angular velocity sensor detects a pitching motion and a yawing motion of the camera. Here, as the angular velocity sensor, a piezoelectric vibration type sensor that detects the Coriolis force is usually used. Next, the output of the angular velocity sensor is integrated over time to be converted into a shake angle of the camera and converted into target position information of the image stabilizing lens 10. In order to move the antivibration lens 10 according to the target position information of the antivibration lens 10, the current driver is input through the servo circuit so as to compensate for the difference between the target position information of the antivibration lens 10 and the position information. The current driver sends a current according to the input voltage to the coil 14 of the actuator. The actuator moves the anti-vibration lens 10 in a direction substantially perpendicular to the optical axis according to the current flowing through the coil 14. The movement of the image stabilizing lens 10 is detected by the PSD 18 and fed back to the servo circuit. Therefore, the anti-vibration lens 10 is moved so as to stop the movement of the image according to the shake of the camera.

FIG. 5 is a flow chart showing an embodiment of the shake prevention processing sequence from the half-depression of the release button to the exposure. First, when the release button is pressed halfway in step 101, the angular velocity sensor operates in the next step 102 to start detection of shake. Then, in step 103, when the release button is fully pressed,
In the next step 104, centering processing of the image stabilizing lens 10 is performed. The center of the anti-vibration lens 10 is usually performed by aligning the center of the slit 16-1 with the light receiving center of the PSD 18. When the centering of the anti-vibration lens 10 is completed, in step 105, the anti-shake process is started as shown in the block diagram of FIG. Exposure is started after a predetermined time from this start (step 106), and the image is taken.

The reason why centering is performed here is as follows. First, the anti-vibration lens 10 must be able to move uniformly in any direction in response to camera shake in any direction. Therefore, the anti-vibration lens 10 is arranged in the center of the moving range before the anti-vibration lens 10 is moved. Secondly, the closer the optical center of the anti-vibration lens 10 is to the optical axis of the main optical system, the better the resolving power of the optical system. Therefore, centering makes the optical center of the anti-vibration lens 10 coincide with the optical axis of the main optical system. This is because.

FIG. 6 shows a state in which the optical axis of the main optical system faces the vertical direction. At this time, the optical center of the anti-vibration lens 10 does not coincide with the center of the movable range of the anti-vibration lens 10 and the optical axis of the main optical system, and is located slightly to the right in the figure. That is, the anti-vibration lens 10 is attached in advance at a position displaced from the main optical system. Moreover, the support rod 11 is not elastically deformed. In actual shooting, as shown in FIG. 6, it is rare that the optical axis of the main optical system is in the vertical direction, that is, the camera lens is directed upward. Normal shooting is performed with the optical axis of the main optical system oriented in a direction perpendicular to the vertical direction (the lens of the camera is oriented horizontally with respect to the ground).

On the other hand, FIG. 7 shows a state in which the optical axis of the main optical system is oriented in a direction perpendicular to the vertical direction. In this state, the support rod 11 is elastically deformed by the self-weight of the anti-vibration lens 10 and the lens barrel 21 and the like, and the anti-vibration lens 10 is lowered in the direction of gravity, whereby the center of the movable range of the anti-vibration lens 10 and The optical center of the image stabilizing lens 10 substantially coincides with the optical center. Further, the optical axis of the main optical system and the optical center of the image stabilizing lens 10 substantially coincide with each other. In such a state, the centering process of the anti-vibration lens 10 can be performed in the shortest time, and the power consumption during the centering can be minimized.

In the embodiment of the present invention, when the optical axis of the main optical system is arranged in a direction substantially perpendicular to the vertical direction, the optical center of the anti-vibration lens 10 becomes the center of its movable range and the center of its movable range. Although it coincides with both the optical axes of the main optical system, one of them, for example, the optical center of the image stabilizing lens 10 coincides only with the center of its movable range, and does not coincide with the optical axis of the main optical system. Even in this case, a sufficient effect can be obtained. The same applies to the reverse.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the present embodiment, as an example of a method of supporting the vibration proof lens 10, an example in which the four support rods 11 support the lens in a cantilever manner is shown. Any method may be used as long as it can be moved to the above.

[0023]

According to the shake prevention device of the first or third aspect of the invention, in a normal photographing state, the optical center of the shake prevention optical system and the optical axis of the main optical system or the movable range of the shake prevention optical system are set. Since the center is brought closer to each other, it is possible to shorten the time required for the centering process of the shake prevention optical system and further reduce the current consumption. Further, according to the shake preventing apparatus according to claim 2 or 4, when the optical axis of the main optical system, which is the most shooting posture, is arranged in a direction substantially perpendicular to the vertical direction, centering processing is performed. The time required can be shortened and the current consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a shake prevention device of the present invention.

FIG. 2 is a diagram showing an electromagnetic actuator that drives the image stabilizing lens 10 of FIG.

FIG. 3 is a diagram showing a state when a lens barrel 21 (antivibration lens 10) is moved.

FIG. 4 is a block diagram showing an example of shake prevention processing.

FIG. 5 is a flowchart showing an example of a shake prevention processing sequence from half-pressing of the release button to exposure.

FIG. 6 is a diagram showing a state in which the optical axis of the main optical system faces the vertical direction.

FIG. 7 is a diagram showing a state in which the optical axis of the main optical system faces a direction perpendicular to the vertical direction.

[Explanation of symbols]

 10 Anti-Vibration Lens 11 Support Rod 12 Magnet 13 Yoke 14 Coil 15 Yoke 16 Slit Part 16-1 Slit 17 LED 18 PSD 19 Top Plate 20 Bottom Plate 20a Movable Limiting Part

Claims (4)

[Claims] 1. A main optical system, a shake preventing optical system for preventing shake generated by vibration, and the shake preventing optical system is movable in a direction substantially perpendicular to an optical axis of the main optical system. A shake prevention device comprising: a support member elastically supporting the shake prevention optical system, wherein the shake prevention optical system has a deflection amount of substantially zero based on a subsidence amount of a portion including the shake prevention optical system due to its own weight. The shake prevention device is characterized in that its optical center is sometimes attached at a position deviated from the optical axis of the main optical system. 2. The shake preventive apparatus according to claim 1, wherein the shake preventive optical system is arranged such that an optical axis of the main optical system faces a direction substantially perpendicular to a vertical direction. A shake prevention device, characterized in that it is attached so that its optical center substantially coincides with the optical axis of the main optical system when the part including the shake prevention optical system sinks due to its own weight. 3. A main optical system, a shake preventing optical system for preventing shake generated by vibration, and the shake preventing optical system can be moved in a direction substantially perpendicular to an optical axis of the main optical system. A shake prevention device comprising: a support member elastically supporting the shake prevention optical system, wherein the shake prevention optical system has a deflection amount of substantially zero based on a subsidence amount of a portion including the shake prevention optical system due to its own weight. The shake prevention device is characterized in that the optical center is sometimes attached at a position deviated from the center of the movable range. 4. The shake preventive apparatus according to claim 3, wherein the shake preventive optical system is arranged such that an optical axis of the main optical system faces a direction substantially perpendicular to a vertical direction. A shake prevention device, characterized in that it is attached such that its optical center substantially coincides with the center of its movable range by sinking due to the weight of the portion including the shake prevention optical system.