JPH0476525A - Image stabilization device and camera - 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 (Industrial Application Field) The present invention is an anti-vibration means for correcting image blur of an object image on an imaging surface (photosensitive surface) when a camera vibrates due to camera shake or the like. In particular, for cameras equipped with a strobe device or in which a strobe device is attached each time a photograph is taken, the relationship between the flash operation of the strobe device and the anti-vibration operation of the anti-vibration means must be appropriately set. The present invention relates to a camera having an anti-vibration means that effectively prevents deterioration in imaging performance due to anti-vibration.

(Prior art) Image stabilization means (image stabilization device) conventionally optically corrects image blur of an object image on an imaging plane that occurs when a camera (photographing system) vibrates due to camera shake, etc. Various cameras have been proposed.

A camera equipped with this anti-shake means has an anti-shake optical system that corrects image shake by moving the imaging point (object image) on the image plane as the anti-vibration means, and a camera that adjusts the magnitude of camera shake. A shake detection means for detecting the direction, a calculation means for calculating the drive amount of the image stabilization optical system for image shake correction based on the output signal from the shake detection means, and a calculation means for calculating the drive amount of the image stabilization optical system for image shake correction based on the output signal from the calculation means. It consists of driving means etc. for driving the vibration optical system.

Among these, one type of anti-vibration optical system is, for example, a variable apex angle prism whose prism apex angle is variable. For example, in JP-A-61 This is proposed in the publication No.-223819. In addition, for example, Japanese Patent Application Laid-Open No. 2-81020 proposes that part or all of the photographic lens is made into an anti-vibration optical system, and the anti-vibration optical system is decentered parallel to the optical axis in a direction perpendicular to the optical axis. ing.

FIG. 5 is an explanatory diagram of the operation when performing image blur correction using a variable apex angle prism as an anti-vibration optical system.

In the same figure, the variable apex angle prism 50 has two disc-shaped glass plates 51 and 52 arranged at a predetermined interval at the front and back, and the outer periphery of the prism 50 is sealed by a flexible tubular body 53 in the form of a hollow. It is constructed by sealing a transparent liquid 54 inside. In the same figure, the navigation side glass plate 51 is rotatably supported around a rotating shaft 51a, and is configured to be rotated arbitrarily by an actuator (not shown), and the rotation angle at that time is a rotation angle (not shown). Detected by a position detection device. The rear glass plate 52 is rotatably supported in a direction perpendicular to the rotating shaft 51a, and similarly to the front glass plate 51, it is driven and rotated by an actuator and a position detection device (not shown). Corners are detected.

FIG. 5(A) shows a case where the variable apex angle prism 50 does not exhibit a vibration damping function and is a mere parallel plane plate, that is, in a neutral position.

In the same figure, the front and rear glass plates 51 and 52 are located at right angles to the optical axis 55a, and therefore the two glass plates are in a parallel state, so that no prismatic action occurs. In this state, parallel light beams a and b enter the variable apex angle prism 50.
, c pass through the variable apex angle prism as they are, enter the photographing lens 55, and form an image at a point P on the imaging plane 56.

If this camera (photographing device) is shaken (rotated) by an angle θ from the state shown in FIG. 5(A), it will become the state shown in FIG. 5(B). In this state, the variable apex angle prism 50, the photographing lens 55. Since the image plane is tilted by θ, the parallel light beams a, b, and c focus on the point Q, resulting in so-called image blur. The shake detection means provided in a part of the camera detects the shake, and the prism apex angle of the variable apex angle prism 50 is changed by the driving means (actuator) based on the value calculated from the detected value by the calculation means. This corrects image shake. FIG. 5(C) shows a state in which the image blur at this time has been corrected.

In general, the front crow 51 is moved to the rotation axis 51 by an actuator (not shown) based on a value calculated by a calculation means.
When rotated about a, the variable apex angle prism 50 becomes a prism with a finite prism apex angle. Due to the prism action at this time, the parallel light beams a, b, and c are bent at an angle of 0, enter the photographic lens 55, and form an image at a point P on the image plane.

Such image blur correction operation is performed in real time, and control is performed so that the image is always focused on point P no matter how the camera shakes. Further, such control is similarly performed by the rear glass 52 in the direction perpendicular to the paper plane of FIG.

FIG. 6 is an explanatory diagram of the operation in which a photographing lens is used as the image stabilizing optical system, and the photographing lens is eccentrically parallel to the optical axis in a direction perpendicular to the optical axis to correct image blur.

In the figure, 60 is a photographing lens, 60a is an optical axis, and 61 is an imaging plane. The photographic lens 60 is held by a mechanism (not shown) so as to be parallel and eccentric in the up-down direction and the front-back direction (vertical direction) of the plane of FIG. 6, and is driven and controlled by an actuator (not shown). Further, the drive stroke is detected by a position detection device (not shown).

FIG. 6(A) shows a state in which the photographing lens 60 is in a neutral position in which the image stabilization function is not exhibited;
Parallel light beams a, b, and c incident on 0 are at a point P on the imaging plane 61
Attach a statue to.

Figure 6 (B) shows the angle θ of the camera from the state of Figure 6 (A).
It shows a swinging (rotated) state, and in this state, the parallel light beams a, b, and c are directed to point Q by the photographing lens 60.
The image will be focused on the object, and so-called image shake will occur. Therefore, in order to correct this image blur, an actuator (not shown) is used based on the value calculated by the calculation means from the detection value of the shake detection means, in the same way as explained with the variable apex angle prism in FIG. 5 above. The photographing lens 60 is parallel and decentered in the direction of arrow X from the position shown in FIG. 6(B).

FIG. 6(C) shows the parallel and decentered state at this time, which corrects image blur. That is, the above-mentioned parallel light beams a, b, and c are focused on an image from the position of point Q to point P by the photographing lens 60.

Such an image blur correction operation is performed in real time as in the case of using a variable apex angle prism. Also, the 6th
The same process is performed in the direction perpendicular to the plane of the drawing.

(Problems to be Solved by the Invention) When image shake is corrected using an anti-vibration optical system, the light beam is passed through a variable apex angle prism or through a parallel decentered photographic lens.

For this reason, when image stabilization is performed, the optical performance of the object image decreases, although it is very small compared to the decrease in optical performance due to image shake when image stabilization is not performed, but the optical performance of the object image decreases, albeit slightly, in proportion to the amount of image shake correction. come. For example, when a variable apex angle prism is used, the greater the prism apex angle, the more -1 chromatic aberration occurs due to astigmatism and the influence of dispersion of liquid, gas, etc. sealed inside.

Furthermore, when image stabilization is carried out by making the photographic lens parallel and eccentric, for example, when the entire photographic lens is parallel and decentered as described above, the peripheral light amount of the image on the imaging plane becomes somewhat unbalanced. In addition, when image blur correction is performed by making some lens groups of the photographic lens parallel and decentered, the optical performance deteriorates asymmetrically with respect to the center of the screen, albeit slightly.

In order to exert the anti-vibration function and minimize the deterioration of optical performance when performing anti-vibration, the present invention provides the anti-vibration function of the anti-vibration optical system and the strobe light emission of the anti-vibration optical system when photographing using a strobe device. The purpose of the present invention is to provide a camera having an anti-vibration means which can appropriately set the relationship with motion, extremely reduce deterioration of optical performance due to anti-vibration, and obtain good images.

(Means for Solving the Problems) A camera having an anti-vibration means of the present invention includes an anti-vibration means for correcting image blur of an object image on an imaging plane when the camera vibrates, and a strobe device. In the existing camera having an anti-vibration means, the strobe device is characterized in that during strobe photography, the strobe device emits strobe light based on the anti-vibration operation of the anti-vibration means.

Particularly, in the present invention, the strobe device is characterized in that the strobe light is emitted in the vicinity of a neutral position where the vibration isolating means does not exhibit its vibration damping function.

Further, if the strobe device does not return to the vicinity of the neutral position where the vibration isolating function is not exerted during the exposure operation of the camera, the strobe device forcibly returns the vibration isolator to the neutral position before the end of exposure. It is characterized by a strobe light.

(Embodiment) FIG. 1 is a schematic diagram of a main part showing a part of the configuration and circuit of a first embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of the present invention.

In FIG. 1, 1 is a camera body, and 2 is an anti-vibration optical system constituting an element of an anti-vibration means, which in this embodiment is comprised of a variable apex angle prism. The variable apex angle prism 2 has a front glass plate 3, a rear glass plate 4, a flexible cylindrical body 5, and a liquid 6 sealed inside. Variable vertex angle prism 2
The optical action of is essentially the same as that shown in FIGS. 5(A)-(C). A front holding ring 7 holds the front glass plate 3. A rear holding ring 8 holds the rear glass plate 4. A coil 9 (10) made of copper wire wound in a flat shape is fixed to an arm portion 7a (8a) provided on one side of the front (rear) retaining ring 7 (8), and an arm portion 7b (8a) provided on the other side. A slit is formed at the tip of 8b). The front (rear) holding ring 7 (8) is rotatably held around an axis 7C (8C) perpendicular to the optical axis.

A yoke 11 and a permanent magnet 12 are arranged between the yokes 11, and these elements constitute a closed magnetic circuit. Further, the yoke 11 is arranged to sandwich the coil 9 (10), and is set so that the magnetic field passes through the coil 9 (10) in a perpendicular direction. Therefore, when a current is applied to the coil 9 (10), a driving force is generated in the coil according to Fleming's law, and the front holding ring 7 and the rear holding ring 8 rotate freely around the shafts 7a and 8a, respectively. At this time, the front (backward)
Since the glass plate 3 (4) moves integrally with the front (rear) holding ring 7 (8), the movement of the coil 9 (10) becomes a rotational movement of the front (rear) glass plate 3 (4).

As a result, the prism apex angle is changed in the same manner as the operation shown in FIG. Reference numeral 13 is a light emitting element such as a light emitting diode. Reference numeral 14 denotes a light receiving element, which has a characteristic that its output signal changes depending on the incident position of the light beam, and is arranged opposite to the slit provided in the arm part 7b (8b) of the front (backward) retaining ring 7 (8). has been done.

The variable apex angle prism 2 is formed by the light emitting element 13 and the light receiving element 14.
The drive angle (prism apex angle) of the prism is detected. That is, the light beam emitted from the light emitting element 13 is incident on the slit surface,
Of these, only the light beam that has passed through the slit is made to enter a predetermined position on the surface of the light receiving element 14. At this time, the position of the slit moves in accordance with the rotation of the front (rear) holding ring 7 (8), and accordingly, the light receiving position (incidence position) of the light beam received by the light receiving element 14 also changes. In this embodiment, the driving angle of the front (rear) glass plate 3 (4) is detected from the output signal from the light receiving element chip 4 at this time.

15 is a lens barrel, inside which is a photographic lens 16.
is retained. 17 is an image forming surface (photosensitive surface). 1
Reference numeral 8 denotes a P shake detection means which detects the amount of shake in the pitching direction (vertical direction) of the camera. Reference numeral 19 denotes Y shake detection means for detecting the amount of shake in the yawing direction (horizontal direction) of the camera. These P (Y) shake detection means 18 (19)
For example, the structure of JP-A-1-296106 by the present applicant is
It is disclosed in the publication No.

20 is a xenon tube that emits strobe light. 2
1 is a reflective shade that efficiently irradiates the strobe light from the xenon tube 20 toward the subject.

22 is a release switch of the camera, and 23 is a distance measuring device, which measures the distance to the subject. As the distance measuring device 23, for example, one using a known active type triangulation method using a light projecting element and a light receiving element is used. Reference numeral 24 denotes a P drive circuit, which drives the coil 9 that controls pitching direction correction. 25 is a Y position detection circuit, which detects the correction angle of the variable apex angle prism 2 in the yawing direction. Reference numeral 26 denotes a P-shake detection circuit which drives the P-shake detection means 18 to detect the amount of vibration in the pitching direction. 27 is a Y deflection detection circuit;
The shake detection means 19 is driven to detect the shake amount in the yawing direction. A release circuit 28 detects the state of the release switch 22. A distance measuring device 29 drives the distance measuring device 23 to measure the distance to the subject. 30 is a light emitting circuit, which is a xenon tube 20
controls the light emission. A Y drive circuit 31 drives the coil 10 that controls correction in the yawing direction.

32 is a P position detection circuit which detects the correction angle in the throat direction of the variable apex angle prism 2. 33 is a microcomputer (hereinafter referred to as rCPUJ), which drives and controls the various circuits mentioned above.

Next, the operation of this embodiment will be explained with reference to the flowchart shown in FIG.

When a main switch (not shown) is turned on, the camera starts operating, and the CPU 33 is activated to operate the release circuit 28 and detect the photographer's intention to take a picture. When the photographer presses the release switch 22 for the first stroke, SWI is turned on, the release circuit 28 detects this state, and the CP
[J33 is p (y) shake detection circuit 26 (27), P
(Y) position detection circuit 32 (25), P (Y) drive circuit 24 (31), distance measurement circuit 29, and photometry circuit (not shown) are activated. The CPU 33 calculates the drive angle of the variable apex angle prism 2 based on the detected value of the P (Y) shake detection circuit 26 (27), and
The drive angle of the variable apex angle prism 2 detected in step 5) becomes the calculated value <P(Y) The drive circuit 24 (31) is used to move the variable apex angle prism 2 in real time in the ink direction and the yaw direction, respectively. to correct image shake. The CPO 33 also calculates the distance to the subject using the distance measurement circuit 29, measures the subject brightness using a photometry circuit (not shown), determines the exposure time and the aperture diameter of the photographic lens 16, and at the same time enters the strobe operating state. Determine.

Next, the CPU 33 checks the SWI status again and
If it is OFF, it is determined that the photographer's intention to shoot has been interrupted, and the operation goes to the stopped state, which will be described later. If it remains ON, it remains inactive until the photographer presses the release switch 22 for the second stroke and SW2 is turned ON. Maintain state, SW2 or O
If it is N, it is determined whether or not it is flash photography.The judgment result from the subject brightness mentioned above and the forced flash S of manual operation are used.
When operating the strobe device (judging from the state of W, etc.), the appropriate amount of light emitted by the strobe is determined from the above-mentioned subject distance information, and the light emitting circuit 30 is activated. Thereafter, the focus lens of the photographic lens 16 is driven to adjust the focal length based on the above-mentioned subject distance information.

Next, the variable apex angle prism 2 is reset to zero in the following manner. As for operation, p (y) shake detection circuit 26 (2
The variable apex angle prism 2 is forcibly positioned at the neutral position regardless of the output value in step 7), and the above-described shake correction operation is started again from this neutral position.

Note that the neutral position here refers to a position where the prism apex angle of the variable apex angle prism is 0, the whole becomes a parallel plane plate, and the anti-vibration function is not exhibited. At this neutral position, the passing light flux is hardly affected by optical performance. In this embodiment, during exposure, the anti-vibration optical system (variable apex prism) is used as close to the neutral position as possible to avoid deterioration in optical performance as much as possible.

After that, the shutter is opened to start exposure. At this time, if flash photography is not being performed, exposure is completed after proper exposure is performed using an exposure time and aperture diameter corresponding to the brightness of the subject measured by the photometry circuit described above. then p (y)
Shake detection circuit 26 (27), P (Y) position detection circuit 3
2 (25).

p (y) The drive circuit 24 (31), the distance measurement circuit 29 and the photometry circuit are stopped, the operation is completed, and the SWI returns to the standby state. In the case of flash photography, exposure is started after the variable apex prism 2 is reset to zero in the same manner as described above. At this time, during exposure, the correction angles in the trundle direction and the yaw direction are detected by the position detection circuit 32 (25), and the strobe light is emitted when the variable apex prism 2 is located near a position that can be considered as the neutral position. After that, the exposure is continued until the exposure corresponding to the brightness of the subject measured by the photometry circuit is completed.After the exposure is completed, the operation is stopped in the same manner as described above and the SWI standby state is resumed. Furthermore, if the variable apex angle prism 2 is not positioned at a position that can be considered as a neutral position during exposure, the exposure is terminated after forced light emission immediately before the end of exposure, and the above-mentioned stopping operation is performed.

As described above, in this embodiment, strobe photography is performed in a state where the deterioration in optical performance when using the image stabilization means is extremely minimized.

Generally, it is possible to correct image blur and obtain a good image by using a vibration reduction means, but it is very difficult to completely eliminate image blur. For example, the amount of image blur on the image plane generally increases as the exposure time increases, and therefore, even if image blur is corrected, the remaining amount of correction also increases. For this reason, if the exposure time exceeds a certain limit, image blur exceeding the allowable value will occur as a result.

If the exposure time limit is exceeded in this way, usually
Strobe photography is used, but if the strobe light reaches the subject, it is better to use strobe photography to obtain a better image with less image blur as far as the main subject is concerned. In other words, the exposure of the main subject is dominated by strobe light, and since the exposure time of the strobe light is instantaneous, image blur on the image plane can be almost ignored. Therefore, the only cause of the deterioration of the optical performance is the deterioration of the optical performance due to the deviation of the anti-vibration optical system from the neutral position, as explained in the above-mentioned conventional example.

As a result, a better image can be obtained if the strobe light is emitted when the anti-vibration optical system is located near the neutral position.

Therefore, when performing strobe photography, it is conceivable to perform the exposure operation with the image stabilization optical system held at a neutral position without performing image shake correction from the beginning. In this case, for the main subject that the strobe light reaches, an image without image blur can be obtained with proper exposure. However, sufficient exposure cannot be obtained for a background that is farther away than the main subject.

In order to obtain proper exposure for such a background, long exposure using natural light is required.

However, if image blur correction is not performed, image blur will increase. A good example is daytime sync when backlit, where the main subject is determined by the strobe light exposure and the background is determined by natural light.

Therefore, in such a case, the present invention allows the main subject to be exposed using strobe light without image blur, and the background to be imaged using natural light with an anti-shake effect. It is possible to obtain an image without deterioration in optical performance that occurs when the vibratory optical system is corrected.

FIG. 3 is a schematic diagram of main parts showing the configuration and circuit parts of a second embodiment of the present invention. In this figure, the same elements as those shown in FIG. 1 are given the same reference numerals.

In FIG. 3, numerals 35 and 36 are lenses constituting a photographing lens. In this embodiment, the lens 35
is used as an anti-vibration optical system.

The lens 35 is held by a front lens frame 37, and the lens 36 is held by a rear lens frame 38.

Reference numeral 39 is a front lens base plate which holds the front lens frame 37 and is attached to the main body 1 via four wooden wires 40 forming a parallel link, and can freely move in parallel within a plane perpendicular to the optical axis. It is composed of Reference numerals 41 and 42 each indicate a winding coil, which is fixed to the front ball base plate 39, and generates a driving force for driving the front ball base plate 39 in the vertical direction, the left-right direction, and the left-right direction, respectively. 43 and 44 each form a U-shaped magnetic path with a yoke, and in combination with a permanent magnet 45 constitute a closed magnetic circuit, and the coils 41 and 42 constitute a moving coil type actuator. are doing. Reference numeral 46 indicates a light emitting element, and reference numeral 47 indicates a light receiving element, whose output signal changes depending on the incident position, and which are disposed opposite to the slit 39a provided in the front ball base plate 39. The front ball base plate 3 is
9 (that is, the lens 35) is detected in the vertical and horizontal directions.

The main difference in the image stabilization operation in this embodiment compared to the first embodiment is that instead of using a variable apex angle prism as an anti-vibration optical system, a part of the lens 35 of the photographing lens is made parallel and decentered. The other structure is similar to that shown in FIG. 1 in terms of wood structure.

That is, the control method is the same as the flowchart of FIG. 2 shown in the first embodiment, except that the lens 35 is parallel and decentered when the image stabilization function is exerted.

In the second embodiment, as in the first embodiment, the main subject is exposed to strobe light without image blur, the background is exposed to natural light with an image stabilization effect, and the main subject is With this method, it is possible to obtain an image without deterioration in optical performance that occurs when performing a correction operation of the anti-vibration optical system.

FIG. 4 is a flowchart showing the operation of the third embodiment of the present invention.

The operating principle in this embodiment is the above-mentioned 1. Second, it is applicable to both embodiments. In this embodiment, the first
What differs from the second embodiment is that the operation is specified in the case where the anti-vibration optical system does not reach a position that can be considered as a so-called neutral position during the anti-vibration operation from the start of exposure to the end of exposure. . Specifically, if the anti-vibration optical system does not reach a position that can be considered as a neutral position until the end of exposure, the anti-vibration optical system is forced to the neutral position just before the end of exposure and the flash is emitted. This means that the exposure is completed.

According to the above configuration, even if the anti-vibration optical system does not come to the neutral position during exposure, it is possible to obtain an image of the main subject using strobe light without image blur and without deterioration in optical performance due to correction operations.
Moreover, since the background is exposed to dominant natural light, the influence of strobe light is small and it is possible to obtain a good image with an anti-vibration effect.

In addition to the above-mentioned anti-vibration optical system in the present invention, for example, Japanese Patent Publication No. 57-7415 No. 5, Japanese Patent Publication No. 57-741
Publication No. 6, Special Publication No. 56-34847, Special Publication No. 1983
Optical elements proposed in Publication No.-40804 etc. can be applied.

(Effects of the Invention) According to the present invention, in strobe photography, by configuring the strobe device to emit strobe light in the vicinity of a position that can be considered as the anti-shake optical system or the neutral position, optical performance due to image shake and correction operation can be improved. To achieve a camera having an anti-vibration means capable of obtaining a good image of a main subject with extremely little deterioration in image quality, and also being able to obtain a good image with an anti-vibration effect as a background image. I can do it.

[Brief explanation of the drawing]

1st. FIG. 3 shows the first embodiment of the present invention. FIG. 2 is a flow chart showing the operation of the first embodiment of the present invention, and FIG. 4 is a schematic diagram showing the operation of the third embodiment of the present invention. Flow chart diagrams shown in Figures 5 and 6
The figure is a schematic diagram of a main part of an optical system showing an image blur correction operation using a conventional anti-vibration optical system. In the figure, 1 is the camera body, 2 is the anti-vibration optical system, 9° 10 is the coil, 11 is the yoke, and 12 is the permanent if! 13 is a light emitting element, 4 is a light receiving element, 16 is a photographing lens, 17 is an imaging plane, 18. 19 is a shake detection means, 20 is a xenon tube, 22
23 is a release switch, 23 is a distance measuring device, 24.3 is a drive circuit, 25.32 is a position detection circuit, and 26.27 is a shake detection circuit. (B) Figure (C) Figure 1

Claims (3)

[Claims] (1) In a camera equipped with an anti-vibration means that has a strobe device and an anti-shake means for correcting image blur of an object image on the imaging plane when the camera vibrates, the strobe device is A camera having an anti-vibration means, characterized in that a strobe light is emitted based on the anti-vibration operation of the anti-vibration means. (2) A camera having a vibration isolating means according to claim 1, wherein the strobe device emits a strobe light in the vicinity of a neutral position where the vibration isolating means does not exhibit a vibration damping function. (3) If the strobe device does not return to the vicinity of the neutral position where the anti-vibration function does not function during the exposure operation of the camera, the strobe device forcibly returns the anti-vibration means to the neutral position before the end of exposure. 2. A camera having an anti-vibration means according to claim 1, characterized in that a strobe light is emitted from the camera.