JP2000267149A - Image blur correcting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image blur correcting device mounted on optical equipment such as a camera, capable of facilitating focusing or the decision of composition in the case of observing an object image through a finder and restraining wasteful power consumption. SOLUTION: In the case of confirming that a signal is generated from a photointerruptor when a photographer executes focusing by manual operation (S200), the defocusing amount D of a focusing lens is calculated based on voltage output from the AF sensor (S202). Whether or not the absolute value of the defocusing amount D exceeds a threshold (m) is judged (S204). When the defocusing amount D is equal to or under the threshold (m), blur amount is detected from output from an angular sensor and driving amount is calculated (S206) and a correction lens is driven (S208). When the defocusing amount D is larger than the threshold (m), the driving of the correction lens is stopped (S210), and image blur correction is not executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for deflecting an optical axis of a finder optical system when an optical device vibrates with respect to an object to be observed due to a camera shake or the like, and an image of the object to be observed due to vibration of the optical device. The present invention relates to an image blur correction device for canceling the movement of a finder on a finder.

[0002]

2. Description of the Related Art A conventional image blur correction device is mounted on, for example, a camera, calculates an amount of blur by integrating an output signal from an angular velocity sensor provided as a blur detecting means, and based on the calculation result. By driving the correction optical system provided in the optical path of the photographing optical system, the movement of the object image, that is, the movement of the object image on the image receiving surface of the camera, for example, the film surface or the light receiving surface of the photoelectric conversion element is corrected. I do.

In general, a camera having a conventional image blur correction function continuously performs processing such as detection of blur for correction and calculation of a drive amount of a correction optical system for blur correction from the time when the power is turned on. However, the correction optical system is actually driven to correct the image blur on the image receiving surface only during the period when the shutter is released and the exposure and photographing are performed.

[0004]

However, in the above-described camera having the conventional image blur correction function, the image blur correction function is not activated when the photographer observes the subject image through the viewfinder. When the camera shakes due to camera shake or the like, the subject image vibrates and hinders focus adjustment and composition determination.

[0005] On the other hand, if the image blur correction function is always activated after the power is turned on, even when the photographer is not actually observing the subject image through the viewfinder, that is, even when correction is not required, the image blur correction function is performed. The shake compensation function will be activated,
There is a problem that power consumption increases and the battery is wasted.

The present invention solves the above-mentioned problems, and is mounted on an optical device such as a camera to facilitate focus adjustment and composition determination when observing an object image through a finder, and to reduce power consumption. It is an object of the present invention to provide an image blur correction apparatus capable of suppressing unnecessary consumption of the image.

[0007]

SUMMARY OF THE INVENTION An image blur correction apparatus according to the present invention detects a finder optical system for guiding at least a part of a light beam from an object to be observed for observation by a user and a shake of an optical device. A blur detection unit, a correction optical system that deflects the optical axis of the finder optical system, and a drive that drives the correction optical system based on a signal from the shake detection unit so as to cancel the movement of the image of the observation object due to the shake of the optical device. Means, a defocus amount detecting means for detecting a defocus amount of a lens constituting the finder optical system, a defocus amount determining means for comparing the defocus amount with a threshold value, and a defocus amount determining means for setting the defocus amount to a threshold value. And a drive control means for activating the drive means when it is determined that the following.

Preferably, the finder optical system is provided in the camera, and part of the finder optical system includes a photographing optical system of the camera for forming an image of the object to be observed on the imaging surface as a subject image.
The correction optical system is provided in the photographing optical system.

The defocus amount detecting means detects, for example, a defocus state of the focusing lens group in the photographing optical system.

The defocus amount detecting means detects, for example, a defocus state of the focusing lens group in the finder optical system.

Preferably, the defocus amount detecting means includes:
A lens moving state detecting means for detecting a moving state of the focusing lens group is provided, and while the movement of the focusing lens group is detected by the lens moving state detecting means, the defocus amount is continuously detected.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a camera 1 having an image blur correction function according to the present embodiment.

The camera 1 is provided with a photographic optical system 2 for forming a subject image on a film F, which is an image receiving surface, and a subject light which enters through a part of the photographic optical system 2 and is reflected by a quick return mirror 3. A finder optical system 4 for guiding the photographer's eyes, a sub-mirror 8 for reflecting the subject light transmitted through the quick return mirror 3 and guiding to the AF sensor 7, a shutter button 20, a control unit 30 for controlling the entire camera, and an image blur correction unit 40 Is provided.

The camera 1 includes angular velocity sensors 51 and 52 functioning as shake detecting means for detecting shake of the photographing optical system 2 with respect to a subject, and a lens for detecting movement of a lens in the photographing optical system 2 in the optical axis direction. A movement detecting means 60 is provided.

The shutter button 20 is a two-stage switch, and the photometric switch is turned on when the shutter button 20 is depressed one stage.
Then, when it is pushed in two steps, the release switch is turned on.
The ON / OFF information of these switches is transmitted to the control unit 30.
Is input to

The angular velocity sensor 51 detects the angular velocity of the rotational movement of the camera in the vertical direction (vertical direction) in FIG. 1, and outputs a voltage to the control means 30 according to the angular velocity in the direction due to camera shake or the like. The angular velocity sensor 52 is a sensor that detects the angular velocity of the rotational movement of the camera in a direction (horizontal direction) perpendicular to the paper surface of FIG. 1, and outputs a voltage corresponding to the detected angular velocity to the control unit 30.

The image blur correcting means 40 comprises a correcting optical system for deflecting the optical axis of the photographing optical system 2 and a driving means for driving the correcting optical system. The driving means includes the control means 30
The correction optical system is driven so as to cancel the movement of the object image formed by the photographing optical system 2 on the film surface based on the command of the photographing optical system 2, and the optical axis of the photographing optical system 2 is set in the direction perpendicular to the paper surface and in the paper surface. Deflected independently of each other in parallel directions.

The control means 30 includes a lens movement detecting means 60
When the movement of the lens is detected, and during photographing, the image blur correction means 40 is driven based on the input signals from the angular velocity sensors 51 and 52, thereby driving the image blur correction means 40 on the film surface F and in the viewfinder visual field. Is corrected.

Although the photographing optical system 2 is shown as a single lens in FIG. 1, it is actually composed of a plurality of lenses or lens groups, and a part thereof for focusing or zooming, or All can move in the optical axis direction. In the present embodiment, the lens movement detecting means 60
Detects movement of a lens group involved in focusing (hereinafter, referred to as a “focusing lens”) among the lenses constituting the imaging optical system 2. Further, the correction optical system of the image blur correction means 40 may constitute one of a plurality of optical systems constituting the photographing optical system 2.

At the time of observation, the quick return mirror 3 is shown in FIG.
Is positioned at the position shown in FIG. Therefore, the photographing optical system 2 including the focusing lens and the image blur correcting unit 40
The light flux of the subject incident through the correction optical system is reflected by the quick return mirror 3 and guided to the focusing screen B. The image of the subject on the reticle B is inverted by the pentaprism 4, and the observer passes the reticle B through the eyepiece lens 9.
The upper image can be observed as an erect image. That is, in the present embodiment, the finder optical system includes the photographing optical system 2 including the focusing lens, the correction optical system of the image blur correction unit 40, the quick return mirror 3, the focusing screen B, the pentaprism 4, and the eyepiece lens 9. ing.

The quick return mirror 3 and the sub-mirror 8 are retracted to a position facing the reticle B by a mirror driving mechanism (not shown) during photographing. As a result, at the time of photographing, the luminous flux of the subject is guided to the film surface F via the photographing optical system 2 including the focusing lens and the correction optical system of the image blur correction means 40, and a subject image is formed on the film surface F. . In this manner, the subject image is exposed on the film surface F, and the recording of the subject image is performed.

The focusing lens is configured to move in the optical axis direction by a known cam mechanism (not shown) by rotating the lens barrel 5. The lens barrel 5 is rotated by a motor provided on the body or the lens unit of the camera 1 or by a manual operation of the focusing operation ring 55 of the photographer himself.

The AF sensor 7 is a conventionally known sensor that detects a defocus amount of the photographing optical system 2 by a phase detection method. An image sensor (not shown) in the AF sensor 7 is disposed at a position optically equivalent to the reticle B and the film surface F. Therefore, the focus state on the reticle B is equivalent to the focus state on the film surface F. When the image on the reticle B formed by the photographic optical system 2 is formed, in other words, the photographic optical system When the focus position by 2 coincides with the reticle B, the camera is in focus.

The AF sensor 7 detects the focus state of an image on the film surface F (planned focal plane) formed by the photographing optical system 2 as a defocus amount. That is, the AF sensor 7 is a defocusing device that indicates how much the current focal position of the image formed by the imaging optical system 2 including the focusing lens is shifted from the reticle B or the film surface F in the optical axis direction and how much. Detect the amount. Control means 3
In the case of 0, the driving direction and the driving amount of the focusing lens are calculated based on the defocus amount detected by the AF sensor 7, and the focusing lens is driven based on the calculation result of the control unit 30 to perform automatic focus adjustment. .

The lens movement detecting means 60 includes a pinion gear 61 which meshes with a rack 5a provided on the outer periphery of the lens barrel 5.
And a slit plate 6 provided coaxially with the pinion gear.
2 and a photo interrupter 63 provided with the slit plate 62 interposed therebetween. The slit plate 62 is provided with a number of slits radially about the rotation axis. The photo interrupter 63 includes a light emitting unit 63a and a light receiving unit 63b opposed to each other with a slit plate interposed therebetween. A periodic signal corresponding to the brightness of light is output from the light receiving unit 63b as the slit plate 62 rotates. Is done. As described above, the lens barrel 5 is rotated by the motor provided on the body or the lens unit of the camera 1 in the case of auto focus, and is manually rotated by the photographer in the case of manual focus. Accordingly, a pulse signal is output from the light receiving section 63b in accordance with the rotation of the slit plate 62 interlocked with the rotation of the lens barrel 5 due to focusing.

Note that a single-lens reflex camera having an autofocus function is provided with a detecting means comprising a slit plate and a photo interrupter as described above in order to monitor the driving amount of a lens driving motor. In the present embodiment, this detection means is also used as a lens movement detection means, thereby suppressing an increase in parts, and
The lens movement can be detected in both cases of auto focus and manual focus. However, in order to realize the invention, it is sufficient to be able to determine that the lens is moving. For example, the driving current of the motor for autofocus may be detected and used as a signal, or a part that moves by focusing may be used. And a magnet that does not move and a magnetic register (MR)
nce) A sensor or a Hall sensor may be provided so as to be opposed, and output signals of these sensors may be used.

FIG. 2 shows the structure of the image blur correcting means 40. The correction lens 401 constituting the correction optical system is fixed to the first rotation plate 420 while being fitted in the lens frame 410, and the first rotation plate 420 is connected to the second rotation plate 430 via the rotation shaft 421. To be rotatable. Further, the second rotation plate 430 is rotatably attached to the substrate 440 via a rotation shaft 431 projecting 90 degrees away from the rotation shaft 421 about the optical axis O of the photographing optical system. Substrate 440
Is fixed to the camera 1.

With the above configuration, the correction lens 401
The rotation of the first and second rotation plates 420 and 430 causes the optical axis O
Are held so as to be displaceable in the directions indicated by arrows H and V in the figure in a plane perpendicular to the direction.

The lens frame 410 has a large diameter part 411 and a small diameter part 412, and the small diameter part 412 is fitted into the opening 422 of the first rotating plate 420. Rotation axis 4 of first rotation plate 420
21 is inserted into a shaft hole 439 formed in the second rotation plate 430. An arm 424 having a screw hole 423 is provided on the opposite side of the rotation shaft 421 across the opening 422.

A screw member 426 connected to the rotating shaft of the motor 425 via a flexible joint is screwed into the screw hole 423. The motor 425 is connected to the second rotating plate 4
It is fixed on 30. When the motor 425 is driven, the first rotation plate 420 is driven to rotate about the rotation shaft 421 in the direction indicated by the arrow V in accordance with the rotation direction of the screw member 426.

At the tip of the drive arm 424, a permanent magnet 4
The MR sensor 428 for detecting the position of the permanent magnet 427 is provided on the second rotating plate 430 so as to face the permanent magnet 427. Control means 30
Detects the displacement of the lens 401 in the direction of the arrow V based on the output signal of the MR sensor 428.

The rotation shaft 431 of the second rotation plate is connected to the substrate 440.
Is inserted into the shaft hole 449 formed in the hole. Second rotating plate 43
0 has an opening 432 through which the small diameter portion 412 is inserted. The opening 432 has a size that does not hinder the movement of the small diameter portion 412 due to the rotation of the first rotation plate 420 when the first rotation plate 420 is assembled to the second rotation plate 430.

A drive arm 434 having a screw hole 433 is provided on the opposite side of the rotation shaft 431 with the opening 432 interposed therebetween. A screw member 436 connected to the rotation shaft of the motor 435 via a flexible joint is screwed into the screw hole 433. When the motor 435 is driven, the second rotation plate 430 is driven to rotate about the rotation shaft 431 in the direction indicated by the arrow H in accordance with the rotation direction of the screw member 436.

At the tip of the drive arm 434, a permanent magnet 4
An MR sensor 438 is provided on the substrate 440. The control means 30 includes the MR sensor 4
The displacement of the lens 401 in the direction of the arrow H is detected based on the output signal of 38.

The substrate 440 is provided with an opening 442 through which the small diameter portion 412 is inserted. The opening 442 has a size that does not hinder the movement of the small diameter portion 412 due to the rotation of the first and second rotation plates.

FIG. 3 shows the image blur correcting means 40 viewed from the photographing optical system 2 in a state where the above-described lens frame 410, the first rotating plate 420, the second rotating plate 430, and the substrate 440 are combined. FIG. FIG. 3 shows a reference state in which the optical axis of the correction lens 401 matches the optical axis O of the photographing optical system. In the reference state, the center of the rotation shaft 421 of the first rotation plate 420, the optical axis O, the permanent magnet 427, and the MR sensor 428 are aligned on a straight line a. Similarly, the center of the rotation shaft 431 of the second rotation plate 430,
The optical axis O, the permanent magnet 437, and the MR sensor 438 are arranged on the straight line b.

FIG. 4 is a block diagram for explaining input / output signals of the CPU 31 constituting the control means 30 described above.
The ON / OFF information of the photometry switch 21 and the release switch 22 linked to the shutter button 20 is stored in a port PI of the CPU 31 as a 1-bit digital path.
1, input to PI2. The voltage outputs of the angular velocity sensors 51 and 52 are output from the A / D conversion ports AD1 and AD
2, the voltage output from the MR sensors 428 and 438 is A
The output signal of the photointerrupter 63 is supplied to the / D conversion ports AD3 and AD4 via the port PI3 for detecting the pulse input.
And the voltage output from the AF sensor 7 is the port PI
4 respectively.

D / A output ports DA1, D of CPU 31
A2 is connected to a motor 425 for driving the first rotating plate 420 and a motor 435 for driving the second rotating plate 430 via motor driving circuits 461 and 462, respectively. The CPU 31 determines the amount of movement of the correction lens required to correct image blur based on the above-described input signal.
25, calculates the amount of driving of the motor 435, and outputs a voltage corresponding to the amount of driving from the ports DA1 and DA2.

FIG. 5 is a flowchart showing only the parts necessary for explaining the control of image blur correction from the camera control sequence of this embodiment.

Although two angular velocity sensors are actually used, their output values are processed independently of each other and are used to drive motors corresponding to the respective sensors.

When the power of the camera 1 is turned on and the control is started, the first drive control subroutine of the correction lens is executed (S102) after waiting for the 1 ms timer to expire (S100), and the photometric switch is operated. 21 ON / O
FF is determined (S104). Light metering switch 21 is O
If it is determined to be FF, the process returns to S100. Therefore, while the photometry switch 21 is OFF, the drive control of the correction lens is executed at intervals of 1 ms.

In the first drive control subroutine of the correction lens in step S102, as shown in FIG. 6, it is determined whether or not a signal from the photo interrupter 63 is generated (S200). As described above, the first subroutine is executed from when the power of the camera 1 is turned on until the photometry switch 21 is turned on. S200
In the case where the signal from the photo interrupter 63 is generated, the case where the lens barrel is driven in a state where the photometric switch 21 is OFF, that is, the photographer drives the lens barrel 5 by manual operation to perform focusing. This is the case. Therefore, if the generation of a signal from the photo interrupter 63 is confirmed in S200, S2
In step 02, the defocus amount D of the focusing lens is calculated based on the voltage output of the AF sensor 7.

Next, it is determined whether or not the absolute value of the defocus amount D exceeds the threshold value m (S204). When the defocus amount D is equal to or less than the threshold value m and relatively small, the image blur of the subject image observed by the photographer through the viewfinder is remarkably recognized. Therefore, while detecting the amount of shake from the output from the angular velocity sensor 51, the driving amount is calculated and S
206), the correction lens is driven (S208).

On the other hand, when the defocus amount D is larger than the threshold value m, the influence on the visibility of the subject image in the finder visual field is extremely small even if image shake occurs due to camera shake or the like. Therefore, the driving of the correction lens is stopped (S2
10), no image blur correction is performed.

In a camera having an autofocus function, focus detection is generally performed by turning on a photometric switch, and the focus lens is driven by a motor based on the result. Therefore, when the autofocus function is used, the movement of the lens is not detected in S102, and the correction lens is not driven. However, when the user adjusts the focus by manually operating the focusing operation ring 55 (hereinafter, manual focus), the user does not always perform the focusing after putting his / her hand on the shutter button.
There is a demand that the blur correction function even before the photometry switch is turned on. In the process of S102, it is assumed that manual focusing is performed, and even when focusing is performed by manual operation of the focusing operation ring 55, the image blur correction function is operated to facilitate focusing and composition determination. It is an object.

When the photometric switch 21 is turned on, 1 ms
Wait for the timer to count up (S106),
Photometry is performed, and an aperture value, an exposure time, and the like are obtained by calculation (S108). Here, the second drive control subroutine of the correction lens is executed (S110).

The second drive control subroutine for the correction lens is executed after the photometry switch is turned on, the focus detection is executed as described above, and the drive of the focus lens is started based on the result. I have. Therefore,
In the second drive control subroutine, as shown in FIG. 7, the calculation of the defocus amount D of the focusing lens based on the voltage output of the AF sensor 7 is performed without determining whether or not a signal is generated from the photo interrupter 63. Is performed (S300). The following steps S302, S304,
The processes of S306 and S308 are performed in steps S204 and S2 of the first drive control subroutine of the correction lens shown in FIG.
06, S208 and S210.

When the photometry switch 21 is turned on,
S108, S1 until the release switch 22 is turned on
Step 10 is repeatedly executed every 1 ms. When the photometric switch 21 is turned off, the process returns to S100 and the process is repeated.

If it is determined that the release switch 22 has been turned on (S112), the blur correction is stopped so that the correction lens is not driven unnecessarily in response to vibration before exposure such as mirror driving (S114), and the aperture is set to a predetermined value. , The quick return mirror moves up, the shutter travels, and exposure is started (S116).

During exposure, the amount of blur is detected and calculated (S12).
0), the driving of the correction lens (S122) is performed every 1 ms (S122).
118), repeated until the exposure time ends. If it is determined that the exposure time has elapsed (S124),
The shutter is closed, exposure completion processing such as mirror down and aperture opening is performed (S126), and the correction lens is returned to the neutral position (a position where the optical axis of the photographing optical system and the optical axis of the correction lens match) ( (S128), the sequence ends. When the power of the camera 1 is ON, the process returns to the beginning of the sequence (S100).

The camera 1 of this embodiment is a single-lens reflex camera for guiding a light beam from a subject to a film surface F and a photographer's eye through a partially common optical path. In this case, the viewfinder optical system 4 is defined as a system including the photographing optical system 2 as a part thereof. Therefore, detecting the movement of the focusing lens of the photographing optical system is included in the concept of detecting the movement of a part of the lens of the finder optical system.

The camera according to the present invention is characterized in that at least the image blur of the finder optical system is corrected when the movement of the lens constituting a part of the finder optical system in the optical axis direction is detected. It is not necessary to correct the image blur of the photographing optical system as in the embodiment. That is, in a camera in which the finder optical system and the photographing optical system are independently provided, a configuration in which only the image blur of the finder optical system is corrected may be adopted.

However, in the case of a single-lens reflex camera, if the correction optical system is provided in the photographing optical system, the blur between the finder image and the image on the film surface can be simultaneously corrected as described above, and the auto-focus function is provided. In the case of a camera provided with a camera, there is an advantage that it is also possible to correct the image blur on the autofocus sensor and to perform accurate focus detection. In the above-described embodiment, the photometric switch 2
Before 1 is turned on, the defocus amount is calculated after detecting the movement of the photographing optical system for focusing. Similarly, the movement for zooming is detected and the defocus amount is calculated. You may.

Further, according to the present embodiment, when adjusting the focus through the viewfinder, the blur can be corrected to improve the visibility of the subject image, and the focus and the composition can be easily determined. In addition, by making the image blur correction function only when the defocus amount is equal to or less than the threshold value, it is possible to compare the image blur correction immediately when the power switch is turned on, or the image blur correction when the focusing operation is started. Then, unnecessary power consumption can be suppressed.

As described above, according to the present invention, focus adjustment and composition determination when observing an object through a viewfinder are facilitated while being mounted on an optical device, and wasteful power consumption is achieved. An image blur correction device that can be suppressed can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of a camera having an image blur correction function according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a correction lens driving function of the camera according to the embodiment.

FIG. 3 is a front view of the drive mechanism of FIG. 2 as viewed from a photographing lens.

FIG. 4 is a block diagram illustrating a configuration of a control system of the camera according to the embodiment.

FIG. 5 is a flowchart illustrating a control sequence of the camera according to the embodiment.

6 is a flowchart showing a processing procedure of a first subroutine of correction lens drive control of FIG.

7 is a flowchart showing a processing procedure of a second subroutine of the correction lens drive control of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 camera 2 shooting optical system 4 finder optical system 7 AF sensor 20 shutter button 21 photometric switch 22 release switch 30 control means 31 CPU 40 image blur correction means 51, 52 angular velocity sensor 55 focusing operation ring 60 lens movement detection means 401 correction lens 420 First rotating plate 430 Second rotating plate 440 Substrate

Claims (6)

[Claims] 1. A finder optical system for guiding at least a part of a light beam from an object to be observed for observation by a user, a shake detecting means for detecting a shake of an optical device, and deflecting an optical axis of the finder optical system. A correction optical system, a driving unit that drives the correction optical system based on a signal from the shake detection unit so as to cancel the movement of the observation target image due to a shake of the optical device, and the viewfinder optical system. A defocus amount detection unit that detects a defocus amount of the lens; a defocus amount determination unit that compares the defocus amount with a threshold value; and when the defocus amount determination unit determines that the defocus amount is equal to or less than the threshold value. And a drive control means for operating the drive means. 2. The camera according to claim 1, wherein the finder optical system is provided in a camera, and includes, as a part thereof, a photographing optical system of the camera for forming the observed object image as a subject image on an imaging surface. The image blur correction device according to claim 1. 3. The apparatus according to claim 2, wherein the correction optical system is provided in the photographing optical system. 4. The apparatus according to claim 3, wherein the defocus amount detecting unit detects a defocus state of a focusing lens group in the photographing optical system. 5. The image blur correction apparatus according to claim 1, wherein the defocus amount detection unit detects a defocus state of a focusing lens group in the finder optical system. 6. The defocus amount detecting means includes a lens moving state detecting means for detecting a moving state of the focusing lens group, and while the movement of the focusing lens group is detected by the lens moving state detecting means. 4. The image blur correction device according to claim 3, wherein the detection of the defocus amount is continuously performed.