JPH02183216A - Blurring correcting device - Google Patents

Abstract

PURPOSE:To use a lens with a large aperture ratio and to eliminate image blurring due to a blurring by correcting the attitude variation of a reflecting means due to the blurring and holding the reflecting means at the attitude before the blurring. CONSTITUTION:Light from an object passes through an afocal lens group 1 and is reflected by a reflecting mirror 4 and made incident on an image pickup element 3 through a zoom lens 2. A holding frame 6 which holds a reflecting mirror 4 is provided with an angular velocity detector 8 which detects a horizontal blurring rhoM and a control circuit 13 controls a motor 10 according to its detection output to rotate the holding frame 6 in a direction as shown by an arrow phiM so that the detection output of the angular velocity detector 8 becomes zero. Furthermore, the reflecting mirror 4 is provided with an angular velocity detector 7 which detects a vertical blurring rhoV and a control circuit 12 controls a motor 11 according to its detection output to rotate the reflecting mirror 4 as shown by an arrow phiV so that the detection output of the angular velocity detector 7 becomes zero. Consequently, even when the bright lens having the large aperture ratio is used, a blur-free sharp image is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a camera shake correction device for preventing image shake caused by camera shake in a video camera or the like.

[Conventional technology]

When using a video camera hand-held, if there is camera shake, this is transmitted to the camera body, causing the subject image to shake on the imaging surface of the image sensor, causing shake in the reproduced image and deteriorating the image quality. Modern video cameras are equipped with zoom lenses, and the influence of camera shake poses a major problem, especially when capturing images with the zoom lens set to the telephoto side.

Various devices have been proposed to prevent the effects of camera shake, but one example is the Japanese Patent Application Laid-Open No. 61-14
In Japanese Patent Publication No. 7226, a Humphrey prism as a reversing and displacing optical element and a light reversing and displacing optical element are arranged between an objective lens and a zoom lens, and when a lens case containing these is attached to a camera body. , a technique is disclosed in which a Humphrey prism is used to stabilize a subject image (image) against camera shake.

In this technique, the attitude of the Humphrey prism is controlled in response to camera shake, thereby making it possible to obtain a stabilized image at a fixed position within the lens case.

[Problem to be solved by the invention]

By the way, in the above-mentioned conventional technology, in order to obtain the above-mentioned stable image, the Humphrey prism must be installed at a position f/2 behind the objective lens with a focal length f that forms an image at an arbitrary position within the lens case. Must be. Here, if we look at an object at infinity perpendicular to the optical axis, the image of this object by the objective lens will be formed on a plane perpendicular to the optical axis, but there is a Humphrey prism at the position above behind this objective lens. When the position of the lens changes, at a position within the lens case where a stable object image can be obtained, this object image will be formed on a plane that is inclined with respect to the above-mentioned plane perpendicular to the optical axis. In other words, the subject image is tilted, and the subject image formed by the zoom lens is also tilted with respect to the image plane of the camera on which the subject is imaged. For this reason, on this image plane, even if the subject image is in focus at the center, other parts are out of focus, and the out-of-focus becomes larger toward the periphery.

In order to tolerate this defocus, it is necessary to use a lens with a large reciprocal of the aperture ratio (F number), and for this purpose, it is necessary to use a lens with a small F number, that is, a bright lens with a large aperture ratio. The problem was that it was difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a camera shake prevention device that solves these problems and can prevent image blur caused by camera shake by using a lens with a large aperture ratio.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an afocal lens group with a constant angular magnification that emits light rays from a subject as parallel rays, a reflecting means that reflects the emitted light rays of the afocal lens group, and a camera shaker. and a control means for correcting the change in the posture of the reflecting means caused by the camera shake and maintaining the reflecting means in the posture before camera shake.

The present invention also provides a zoom afocal lens for performing zooming by changing the angular magnification when a light beam from a subject is incident, a reflecting means for reflecting the emitted light beam of the zoom afocal lens, and a reflecting means for reflecting the emitted light beam from the zoom afocal lens. and control means for correcting posture fluctuations.

(Operation) The light rays from the subject pass through the afocal lens group or the zoom afocal lens, become parallel rays, are reflected by the reflecting means, pass through the desired lens system of the camera, and are irradiated onto the imaging plane to form the subject image. be done.

Here, when there is camera shake, the afocal lens group, the zoom afocal lens, the lens system, and the imaging plane are displaced with respect to the absolute spatial coordinate system. In addition, the reflection means also changes its attitude within this coordinate system, but the control means
The light rays along the optical axis of the afocal lens group or the zoom afocal lens before camera shake will be reflected along or almost along the optical axis of the lens system even if each member is displaced as described above due to camera shake. The attitude of the means is corrected. As a result, the subject does not move on the imaging plane, and image blur due to camera shake can be prevented.

On the other hand, displacement of the afocal lens group or the zoom afocal lens due to camera shake causes the subject to be equivalently tilted, and as a result, the subject image is also tilted with respect to the imaging plane. However, due to the afocal lens group or the zoom afocal lens, the subject seen from the camera lens system is at infinity or nearly infinity, and for this reason, the angle of inclination of the subject image with respect to the imaging plane is negligible. It becomes small enough.

Therefore, there is no out-of-focus of the subject image over the entire image plane, and it becomes possible to use a bright lens with a small F number.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of the camera shake prevention device according to the present invention, in which 1 is an afocal lens group with an angular magnification of 2, 2 is a zoom lens, 2a is a ring, 3 is an image sensor,
4 is a reflecting mirror, 5.6 is a holding frame, 6a is an engaging part, 7 and 8 are angular velocity detectors, 9 is a weight part, 10.11 is a motor, 12
．． 13 is a control circuit. FIG. 2 is a partial sectional view taken along the dividing lines A and -A' in FIG. It is marked with a sign.

In FIGS. 1 and 2, an afocal lens group 1 with zero refractive power and an infinite focal length, and a zoom lens 2 consisting of a variator lens group 14, a convencator lens 15, etc. that change the zoom magnification. The holding frame 5 is arranged so that the optical axes 03 and 0□ intersect at right angles, for example.
The positional relationship is maintained fixed. and,
This holding frame 5 has a 0! on the optical axis of the zoom lens 2! The holding frame 6 is attached in a gimbal configuration so as to be rotatable around the
Further, a reflecting mirror 4 is attached to the holding frame 6 so as to be rotatable about an axis perpendicular to the optical axis O4 of the afocal lens group 1 and the optical axis 0□ of the zoom lens 2. The holding frame 6 is provided with a holding part 6a, and the holding part 6 rotates while the holding part 6a contacts the inner surface of a ring 2a provided on the zoom lens 2. O in FIG. 2 is the central axis of rotation of the reflecting mirror 4. Note that the arrow φ□ represents the rotation direction of the holding frame 6 and the rotation direction of the φ9 reflecting mirror 4, and ρ□ and ρ9 represent camera shake in the horizontal and vertical directions, respectively.

The holding frame 5 is provided with a motor 10 that rotates the holding frame 6 in the direction of arrow φ8.
A motor 11 for rotating in the V direction is provided. In addition, the holding plate 6 has horizontal camera shake ρ.

An angular velocity detector 8 is provided to detect the camera shake ρ, and when this detects the camera shake ρ, a control circuit 13 controls the motor 10 according to the detection output so that the detection output of the angular velocity detector 8 becomes zero. Then, the holding frame 6 is rotated in the direction of arrow φ8. Further, the reflector 4 is provided with an angular velocity detector 7 that detects a vertical hand shake ρ, and when this detects a hand shake ρ9, a control circuit 1
2 controls the motor 11 and rotates the reflecting mirror 4 in the direction of arrow φ9 so that the detection output of the angular velocity detector 7 becomes zero.

The reflecting mirror 4 is also provided with a weight portion 9, whereby the reflecting mirror 4 is held in a stable rotating state at the center of inertia. In the initial state without camera shake (not driven by the motor 11), the posture of the reflecting mirror 4 is set so that the light rays along the optical axis 01 of the afocal lens group 1 are reflected along the optical axis 02 of the zoom lens 2. is held by the overlapping portion 9, and when there is a camera shake, the reflector 4 is rotated by the motor 11 while having the force to return to this initial state.

In this configuration, light from a subject (not shown) passes through the afocal lens group 1, is reflected by the reflecting mirror 4, passes through the zoom lens 2, and enters the image sensor 3. As a result, a subject image is formed on the imaging surface of the image sensor 3.

Next, the operation of this embodiment will be explained with reference to FIG. Note that although this operation is related to the vertical camera shake ρ9, the same applies to the horizontal camera shake ρ□.

In the figure, afocal lens group 1° zoom lens 2. Assuming that the image sensor 31 and the reflecting mirror 4 are in the state shown by the solid line, the optical axis of the afocal lens group 1 is 0. Above, a light ray 17 emitted from a distant object 16 passes through the afocal lens group 1 in parallel to the optical axis 01, is reflected by the reflecting mirror 4, and enters the zoom lens 2. Since the incident light of the zoom lens 2 is parallel to its optical axis at, the image of the subject 16 (not shown) formed by the afocal lens group 1 is formed sufficiently far away from the zoom lens 2. This zoom lens 2 allows the image of the subject 16 to be transferred to the image sensor 3.
The image is formed on the imaging plane.

While imaging this subject 16, due to vertical camera shake ρ9, the afocal lens group 1 moves around the rotation axis O of the reflector 4.
．． It is assumed that the zoom lens 2 and the image pickup device 3 are each rotated by an angle θ and are displaced to the positions indicated by broken lines labeled 1' and 2'3', respectively.

Afocal lens 1' and zoom lens 2' at this time
The optical axes o, ', o, ' are the optical axes of the afocal lens group 1 and the zoom lens 2 at their original positions, respectively, 01°0! deviates from the angle θ. For this purpose, the original optical axis 0. The light ray 17 from the subject 16 that is incident on the afocal lens group 1' along the angle θ is inclined from the optical axis O8.

By the way, when a light ray entering an afocal lens group with an angular magnification of γ is inclined at an angle θ with respect to the optical axis at -i, the exit angle ψ of this light ray is expressed by the following equation.

r-tanθ=tanψ-(11 usually,
Since the incident angle θ due to camera shake is sufficiently small at around 2″,
The above formula (1) can be expressed as follows.

T ・θ−ψ (2) Therefore, in FIG. 3, if the angular magnification T of the afocal lens group 1' is 2, the output angular velocity ψ of the output ray 18 is ψ=2θ (2) 3) It becomes. That is, afocal lens group 1. Zoom lens 2. While the image sensor 3 is deflected by an angle θ about the rotation axis 0 of the reflecting mirror 40, the light 118 emitted from the afocal lens group 1' is deflected by an angle 2θ. However, since the afocal lens group 1' has an infinite focal length, the emitted light 18 is parallel.

By the way, the vertical camera shake ρ, and the reflector 4,
As indicated by the broken line 4', the camera is rotated by an angle θ around the rotation axis 0, but this camera shake ρV is detected by the angular velocity detector 7 (Fig. 1), and the above-mentioned In this way, the reflecting mirror 4 is rotated by an angle θ in the direction of the arrow φ9, and returns to the original state shown by the solid line. In other words,
The posture is held fixed with respect to the absolute spatial coordinate system.

Therefore, the optical axis 0'l is set by the afocal lens group 1'.
When the light ray 18 emitted at an emission angle 2θ is reflected by the reflecting mirror 4, it becomes parallel to the optical axis 02' of the zoom lens 2'. At this time, by appropriately setting the distance between the afocal lens group 1 and the reflection jii4 according to the angular magnification γ (=2) of the afocal lens group 1, the original optical axis of the afocal lens group 1' can be adjusted. Incident light 17 along o1
The emitted light ray 18 can be reflected on the rotation axis 0 of the reflection w14. This allows the incident light &? along this original optical axis OI. The outgoing light beam 18 of 117 is transmitted through the zoom lens 2
Therefore, the same subject image is formed on the imaging surface of the imaging device 3' as the imaging surface of the imaging device 3 before the vertical camera shake ρ9 occurs. .

In this way, even if there is camera shake, the reflector 4
By rotating the camera in the direction in which there was no camera shake, the shake of the subject image on the imaging surface of the image sensor 3 is eliminated.

Here, in FIG. 3, when the optical axis OI of the afocal lens group l with an arbitrary angular magnification T is tilted by an angle θ due to camera shake, the original axis of the tilted afocal lens group 1' relative to the optical axis 0'l is The exit angle of the outgoing light ray 18 of the light ray 17 along the optical axis O9 is γθ, as explained above. Further, the optical axis O'2 of the afocal zoom lens 2' formed by the reflecting mirror 4 which is controlled so as to maintain its original state is inclined at an angle of 2θ with respect to the reference reflecting axis O#2.

Therefore, when the outgoing light ray 18 of the light ray 17 along the original optical axis O1 that enters the tilted afocal lens group 1' is reflected by the reflecting mirror 4, this reflected light ray moves from the reference reflection axis O#2 to the optical axis 0. If the reflected light beam is shifted by ±Δθ due to the optical axis O'2, then 2θ=γθ±80=Tθ×α...(4) Stabilize α Let's call it the rate. This stabilization rate α is calculated by the formula (
4), it can be expressed as follows.

α; 2/γ ... (5) When α=1 (therefore, T=2), the light 'a17 along the original optical axis 01 of the moved afocal lens group 1'
is reflected by the reflecting mirror 4 and moved along the optical axis 0'z of the zoom lens 2', and therefore, the subject image on the imaging surface of the image sensor 3' will not move due to camera shake.

When α≠1, the subject image on this imaging plane will be shaken due to camera shake, but when 3 is sufficiently close to 1, the image shake due to the shaking of the subject image on this imaging plane will not be noticeable.

For this reason, the stabilization rate α does not necessarily have to be 1, and there is an acceptable practical range, which varies depending on the size of the imaging surface of the image sensor 3, the focal length of the zoom lens, etc. In these commonly used ranges, 1
It can be set to ±0.25. Therefore, the above formula (
5), the angular magnification γ is 1.6 < r < 2.7 for practical use.

Further, in this embodiment, since the subject is reflected by the reflecting mirror 4 and imaged on the imaging surface of the image sensor 3, the subject image on this imaging surface is horizontally reversed. Now, in Figure 3,
Assuming that the subject 16 is a person with his right hand raised, in a normal video camera, the subject image 16' is correctly formed on the imaging surface of the image sensor 3, as shown by the arrow, as shown in FIG. A correct reproduced image can be obtained by horizontally sweeping from left to right.

In contrast, in this embodiment, a horizontally inverted subject image 16'' is formed on the imaging surface of the image sensor 3 by the reflecting mirror 4, as shown in FIG. 4(b). Figure 4 (a
) If a horizontal sweep is performed in the same way as in the case of ), the reproduced image will be left and right reversed. Therefore, in this embodiment', a horizontal sweep is performed from the right side to the left side, as shown by the arrow in FIG. As a result, a correct reproduced image can be obtained.

FIG. 5 is a partial cross-sectional view showing another embodiment of the image stabilization device according to the present invention, in which 19 is a zoom afocal lens with variable angular magnification, 20 and 21 are internal lenses, 22 is a zoom ring, and 23 is a zoom afocal lens with variable angular magnification; Potentiometer, 24, holding frame, 25
is a relay lens group, 26 is a Hall element, 27 is a magnet, 2
8 is a position control circuit, 29 is an angular velocity control circuit, and the first
Parts corresponding to the figures are given the same reference numerals.

In the figure, the zoom afocal lens 19, the relay lens group 25, and the image sensor 3 are held together by a holding frame 24, a part of which is shown.
The reflecting mirror 4 is held by a holding frame 6, and this holding frame 6 is held by a holding frame 24 in a gimbal configuration.

In the zoom afocal lens 19, the internal lens 20.21 moves by rotating the zoom ring 22,
The angular magnification T changes within the range of 2.4 to 0.3.

A potentiometer 23 is connected to the zoom ring 22, and outputs a signal corresponding to the rotation angle of the zoom ring 22, and hence the angular magnification γ.

A Hall element 26 is provided on one of the reflecting mirror 4 and the holding frame 6, and a magnet 27 is provided on the other so as to face each other, and the Hall element 26 outputs a signal corresponding to the position of the magnet 27.

The detection output signal of the angular velocity detector 7 attached to the reflector 4 is supplied to the angular velocity control circuit 29, which controls the potentiometer 23 according to the angular magnification T of the zoom afocal lens 19.
The output signal of is multiplied by a constant weighted signal.

The detection output signal of the Hall element 26 is also supplied to the position control circuit 28, and the output signal of the potentiometer 23 is multiplied by a predetermined weighted signal. The output signal of the angular velocity control circuit 29 and the output signal of the position control i11 circuit 28 are added, and this added signal is outputted from the control circuit 12 as a control signal for the motor 11. With this control signal, when the angular magnification γ of the zoom afocal lens 19 is between 2.4 and 1.6, even if there is camera shake, the reflector 4 will be the same as there is no camera shake, as explained in FIG. In addition, when the angular magnification T is 1.6 or less, the reflector 4 is maintained at the angular magnification T.
The motor 11 is controlled so that it rotates by an amount corresponding to the rotation of the holding frame 6.

The relay lens group 25 includes a zoom afocal lens 19
, and is reflected by a reflecting mirror 4 to form a subject image on the imaging surface of the image sensor 3.

Next, the operation of this embodiment will be explained.

First, the angular magnification γ of the zoom afocal lens 19 is 2.
If it is in the range of 4 to 1.6, potentiometer 2
The output signal of No. 3 is transmitted to the position control circuit 28 and the angular velocity control circuit 29.
By being supplied to and performing the above arithmetic processing,
The output signal of the position control circuit 28 becomes almost zero, and the control signal output from the control circuit 12 is only the output signal of the angular velocity control circuit 29. The motor 11 is controlled by this control signal, and the reflecting mirror 4 operates in the same manner as the embodiment described in FIGS. 1 to 3.

Next, the angular magnification γ of the zoom afocal lens 19 is 1.
6 or less, the subject image on the imaging surface of the image sensor 3 will be smaller than when the zoom afocal lens 19 is on the telephoto side with a large angular magnification γ of 1°6 or more, and for this reason, Compared to camera shake of the same magnitude, the amount of shake of the subject image is small and does not pose a problem.

When the angular magnification T is 2.4 to 1.6, as explained in FIG. 3, when the entire body is tilted by an angle θ due to camera shake, the reflector 4 is tilted by an angle θ in the opposite direction to this tilt direction. Rotated. Therefore, due to camera shake, the reflecting mirror 4 rotates by an angle θ with respect to the holding frame 6.

However, when the angular magnification γ is small (1.6 or less), if the reflector 4 is controlled in the same way as when it is large, the zoom afocal lens 19
Even though the exit angle ψ due to camera shake is small, the reflecting mirror 4 is rotated by a sufficiently larger angle than the angle required for correction, and the subject image on the imaging surface of the image sensor 3 is shaken considerably. That is, considering the practical range of the stabilization rate α in the above equation (5), the correction by the reflecting mirror 4 exceeds the limit.

Therefore, in this embodiment, when the angular magnification T is small (1.6 or less), the reflecting mirror 4 follows the rotation of the holding frame 6 so that the reflecting mirror 4 does not rotate with respect to the holding frame 6. Rotate. In other words, the reflecting mirror 4 is integrated with the holding frame 6. For this reason, the subject image on the imaging surface of the image sensor 3 is shaken due to camera shake, but as described above, this shake hardly causes a problem. In this way, the Hall element 26 and the magnet 2 are arranged so that the reflecting mirror 4 follows the holding frame 6 and rotates.
7 detects the angle between the reflecting mirror 4 and the holding frame 6, and the motor 11 is controlled by the output signal from the position control circuit 28 so that this angle becomes a predetermined constant value. .

Further, in this embodiment, the angular velocity detector 7 is connected to the holding frame 6.
When the angular velocity of camera shake detected by the angular velocity detector 7 is ω, the reflecting mirror 40 is adjusted by the detection output of the Hall element 26 so that the angle formed by the reflecting mirror 4 and the holding frame 6 is as follows.
By controlling the rotation, it is also possible to obtain stable images at all angular magnifications T.

In this embodiment, by storing everything other than the zoom afocal lens 19 in the case, operations similar to those of a conventional video camera, such as manual zooming, are possible.

FIG. 6 is a partial cross-sectional view showing still another embodiment of the image stabilization device according to the present invention, in which 30 and 31 are right angle prisms, 30a and 31a are reflective surfaces, and the parts corresponding to FIG. They are given the same code.

In the figure, light from a subject (not shown) passes through the afocal lens group 1 and reaches the reflecting surface 30 of the right-angle prism 30.
a, and is further reflected by the reflecting surface 31 of the three rectangular prisms.
The light is reflected by a, passes through the zoom lens 2, and is irradiated onto the imaging surface of the image sensor 3 to form a subject image.

Here, the right angle prism 30 is the reflecting mirror 4 in FIG.
The right-angle prism 31 rotates around the axis O in response to camera shake, and the right-angle prism 31 is held integrally with the zoom lens 2. As a result, even if there is a camera shake, the light rays on the original optical axis OI of the afocal lens group 1 when there is no camera shake are irradiated to the center of the imaging surface, and the shake of the subject image on the imaging surface is eliminated.

FIG. 7 is a partial cross-sectional view showing still another embodiment of the image stabilization device according to the present invention, in which 32.33 denotes triple reflection prisms +32a, 32b, 32c+33a,
33b and 33c are reflective surfaces, and parts corresponding to those in FIG. 6 are given the same reference numerals.

In this embodiment, a triple reflection prism is used in place of the right angle prism shown in FIG.

In FIG. 7, the triple reflection prism 32 has three reflection surfaces 32a, 32b, and 32c, into which the light beam that has passed through the afocal lens group 1 is incident.
The light is sequentially reflected by 32c and 32b and emitted. The triple reflective prism 33 also has three reflective surfaces 33a and 33b.
, 33c, and the light beam emitted from the triple reflection prism 32 is incident on the reflection surfaces 33a, 33c.
, 33b and are sequentially reflected and emitted.

The triple reflection prism 33 is held integrally with the zoom lens 2. The triple reflection prism 32 is stabilized so that the posture does not change even if the posture changes due to camera shake.

The triple reflecting prism is also equivalent to a single reflecting mirror, and stabilizing the triple reflecting prism 32 as described above is equivalent to the operation of the reflecting mirror 4 shown in FIG. Shaking of the subject image on the imaging surface can be prevented.

By the way, in the embodiments shown in FIGS. 6 and 7, there is an even number of light reflecting surfaces, and the subject image on the imaging surface of the image sensor 3 is not flipped horizontally or vertically, which is different from that of a conventional video camera. Since a subject image in the same orientation as that can be obtained, the sweeping of the image sensor 3 can be performed in the same manner as in a conventional video camera.

Note that any prism can be used as long as it is equivalent to a reflecting mirror, even if it has a shape other than these or has an odd number of reflecting surfaces. Furthermore, the sixth
In FIG. 7, a reflecting mirror may be used instead of each prism, or a reflecting mirror and a prism, or different prisms may be used.

FIG. 8 is a partial cross-sectional view showing still another embodiment of the image stabilization device according to the present invention, in which 2b is a filter mounting screw portion, 34 is a converter lens barrel, 35 is a joint portion, 36 is a protrusion, and 37 is a The through hole 138 is a disk portion, 39 is a bearing, and the parts corresponding to those in FIG. 2 are given the same reference numerals.

In the same figure, the converter barrel 34 is attached integrally with the afocal lens group 1, and the holding frame 6 holding the reflecting mirror 4 is attached therein in a gimbal configuration, as in FIG. . A hook-shaped protrusion 36 is provided,
A disc portion 38 that is integrated with the holding frame 6 is fitted into the protrusion 36 via a bearing 39 . Thereby, the holding frame 6 becomes rotatable around the central axis of the through hole 37.

Further, a through hole 37 is provided on the bottom outer surface of the converter barrel 34.
A ring-shaped joint 35 is provided around the periphery of the zoom lens 2, and this joint 35 can be fitted into the filter mounting thread 2b provided at the top of the zoom lens 2. As a result, the converter barrel 34 can be attached to and detached from the zoom lens 2, but when the converter barrel 34 is attached to the zoom lens 2, the subject image on the imaging surface of the image sensor 3 is always focused in the correct direction. A means (not shown) is provided for correctly regulating the orientation of the afocal lens group 1 with respect to the zoom lens 2 so that the image is imaged.

The zoom lens 2, the image sensor 3, etc. constitute a conventional video camera, etc., and by attaching the converter lens barrel 34 to the zoom lens 2, it can be used as a reflector as in the embodiment shown in FIG. By the posture control in step 4, camera shake can be corrected.

When the converter barrel 34 is attached to the zoom lens 2,
The afocal lens group 1 with an angular magnification of 2 serves as a teleconverter lens that apparently has the effect of doubling the focal length of the zoom lens 2. When the focal length of the zoom lens 2 doubles, the movement of the subject image due to camera shake also doubles.
Due to the action of the reflecting mirror 4 described above in FIG. 3, there is no movement of the subject image on the imaging surface of the image sensor 3.

In this way, this embodiment can be attached to and detached from the zoom lens of a conventional video camera, etc., and can prevent camera shake, which is a problem when taking images with a long focal length, and can also produce shake-free images when taking telephoto images. can be obtained easily.

In each of the embodiments described above, when the afocal lens group 1 and the zoom afocal lens 2 (hereinafter collectively referred to as afocal lenses) into which light rays from the subject are incident move due to camera shake, they become attached to the video camera body. (The zoom lens 2 in FIG. 1 and the relay lens group 25 in FIG. 5, etc.)
The object seen through the lens (generally referred to as a relay lens) is tilted, and as a result, the image of the object is tilted with respect to the imaging surface of the image sensor 3. This will be explained below with reference to FIG. 9, in which 40 is an afocal lens, 41 is a relay lens, and 42 is a reflecting means (the reflecting mirror 4, the right-angle prisms 30, 31, and the triple reflecting prism 32 in the above embodiment). .33), and parts corresponding to those in the previous drawings are given the same reference numerals.

In addition, Fig. 9 shows that the afocal lens 40 is
, the relay lens 41, etc. are shown moving, but for the sake of simplicity, the optical axis 01' of the afocal lens 40 and the optical axis Ot' of the relay lens 41 are shown on the same straight line. .

In FIG. 9, if we consider the subject 16 perpendicular to the optical axis of the afocal lens 40 before it moves due to camera shake,
Before the afocal lens 40, relay lens 41, etc. move due to camera shake, the subject image 16a of the subject 16
is the optical axis O of the relay lens 41! This occurs on the imaging surface of the image sensor 3 perpendicular to . That is, the subject image 16a is perpendicular to the optical axis Ot of the relay lens 41, and this subject image 16a
Each part will be imaged on the imaging plane.

On the other hand, due to camera shake, the afocal lens 40, for example, as shown in FIG. Relay lens 41.
When the imaging probe 3 moves, the light ray from the subject 16 along the optical axis of the afocal lens 40 before the camera shake exits from the afocal lens 40 that has moved due to the camera shake at an angle of γθ. This emitted light beam is reflected by the reflecting means 42 and forms an image on the imaging surface of the image sensor 3 along the optical axis O2 of the relay lens 41.

However, the optical axis O1 due to the movement of the afocal lens 40
Due to the inclination of the angle θ, the object 16 is equivalent to being on a straight line 01'' that is shifted by γθ from the optical axis O9.If this equivalent object is represented by 16', this equivalent object 16' is on the straight line 01''. 01''. This means that the equivalent subject 16# is at the optical axis of the afocal lens 40.
The angle γθ is about f with respect to the plane perpendicular to . As a result, a subject image 16 based on this equivalent subject 16' is obtained.
8' is inclined with respect to the imaging plane of the imaging rope 3.

By the way, if the inclination angle of this subject image 168' with respect to the imaging plane is β,
If we take the distance from the center of this lens to the imaging surface as 2, then ! β=tan-'C-tan rθ)...
・(7) becomes.

On the other hand, in each of the embodiments described above, the light rays emitted from the afocal lens 40 are parallel rays, and the subject 16' (therefore, the subject 16) seen from the relay lens 41 can be viewed as infinite or almost infinite; ,
It is possible to set L=oo. As a result, the above formula (7)
Therefore, β can be considered to be almost zero, and the subject image 1
68' will be imaged as a whole on the imaging plane without defocusing.

In this manner, in each of the above embodiments, even if there is camera shake, the subject image is formed on the imaging surface without defocusing as a whole, making it possible to use a bright lens with a small F number.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to prevent blurring of the subject image due to camera shake on the imaging plane, and
A subject image can be formed over the entire image plane without defocusing, and a bright lens with a large aperture ratio can be used to obtain a clear image without shake.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of an image stabilization device according to the present invention, FIG. 2 is a partial sectional view taken along the dividing line AA' in FIG. 1, and FIG. 3 is an explanatory diagram of the operation of this embodiment. , Figure 4 is the first
5 to 8 are partial cross-sectional views showing other embodiments of the image stabilization device according to the present invention, and FIG. FIG. 3 is a diagram showing the inclination of a subject image on an imaging plane. 1.1'...Afocal lens group, 2.2'...
Zoom lens, 3... Image sensor, 4... Reflector, 5
゜6... Holding frame, 7.8... Angular velocity detector, 10.
11...Motor, 12.13...Control circuit, 19.
...Zoom afocal lens, 23... Potentiometer, 25... Relay lens group, 26... Hall element, 27... Magnet, 28... Position control circuit, 29
...Angular velocity control circuit, 30.31...Right angle prism, 32.33...Triple reflection prism, 34...Converter lens barrel, 35...Joint portion, 36...Protrusion, 37
...Through hole, 3B...Disc part, 39...Bearing. j 1st Figure A'-1 3rd Figure 2 Figure 4 Figure 5 Figure 6 1B8 Figure 7a 9th Troop

Claims (1)

[Claims] 1. In a device that forms an image of a subject on an imaging plane through a desired lens system, an afocal lens group with a constant angular magnification that emits light rays from the subject as parallel rays. a reflecting means for reflecting the emitted light beam from the afocal lens group and making it enter the lens system; What is claimed is: 1. An image stabilization device, comprising: a control means for holding the image, and is configured to stabilize a subject image on the imaging plane against camera shake. 2. The camera shake correction device according to claim 1, wherein the angular magnification of the afocal lens group is 2. 3. The image stabilization device according to claim 1, wherein the angular magnification of the afocal lens group is 2.7 to 1.6. 4. The image stabilization device according to claim 1, 2 or 3, wherein the reflecting means is a single reflecting mirror. 5. In claim 1, 2 or 3, the reflecting means includes first and second reflecting members each having an odd number of reflecting surfaces, and the attitude of the first reflecting member is controlled by the control means. the second reflecting member is fixed with respect to the lens system and is configured to reflect the exiting light ray of the first reflecting member and make it incident on the lens system. An image stabilization device characterized by: 6. The image stabilization device according to claim 5, wherein each of the first and second reflecting members is a reflecting mirror, a right-angle prism, or a triple reflecting prism. 7. Claims 1, 2, 3, or 4 provide that the reflecting means is provided in a housing that is integrally attached to the afocal lens group, and that the housing is detachable from the lens system. Features an image stabilization device. 8. In an apparatus that forms an image of a subject on an imaging plane through a desired lens system, a zoom afocal lens and a zoom affocal lens are used to perform zooming by changing the angular magnification when light rays are incident from the subject. a reflecting means for reflecting the emitted light beam from the ocal lens and making it enter the lens system;
An image stabilization device comprising: a control means for correcting posture fluctuations of the reflecting means due to hand shake, and configured to stabilize a subject image on the imaging plane against hand shake. 9. In claim 8, the control means performs control to maintain the reflection means in a pre-shake posture within a predetermined large angular magnification range of the zoom afocal lens, and An image stabilization device characterized in that the reflecting means is held in a posture corresponding to camera shake within a range in which an angular magnification is smaller than the above range. 10. The image stabilization device according to claim 8, wherein the control means varies the amount of correction for the attitude change of the reflecting means due to camera shake depending on the angular magnification of the zoom afocal lens.