JPH09171205A - Camera shake correction optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device effectively performing the camera shake correction of a television camera. SOLUTION: In this device, a 1st lens group 1a constituted of a concave lens G1 and a convex lens G2 and having positive composite focal length and a 2nd lens group 1b constituted of a concave lens G3 and a plate glass or a concave lens G4 and having negative composite focal length are disposed to constitute an afocal system. Furthermore, the device is provided with a means for driving the concave lens G3 of the 2nd lens group 1b in two orthogonally crossed axial directions on a plane perpendicular to an optical axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to camera shake correction of an image pickup apparatus, and more particularly to a camera shake correction optical apparatus for optically performing camera shake correction.

[0002]

2. Description of the Related Art Conventionally, in an image pickup apparatus such as a television camera, image shake due to camera shake has been a problem. In particular, in an image pickup apparatus having an image pickup optical system having a zoom function, the effect of camera shake on a captured image is large on the tele side.

Now, a conventional camera shake correction mechanism will be described with reference to FIGS. 13 to 17.
13A and 13B are views for explaining a conventional electronic image stabilization mechanism, in which FIG. 13A shows an image cutting frame on a CCD, and FIG. 13B shows correction of an optical axis corresponding to the image cutting frame. The calculation of the angle is shown. FIG. 14 is a diagram for explaining a conventional optical image stabilization mechanism. FIG. 15 shows VAP (V
It is a figure which shows the structure of an ary angular prism) element, and FIG. 16 is a figure which shows this operation | movement. Further, FIG. 17 shows a conventional image stabilizing mechanism using plano-concave lens and plano-convex lens, (a) shows the configuration of the optical system, and (b) shows the operating state thereof.

As a camera shake correction mechanism, a CC shown in FIG. 13 is used.
A method of cutting out the image frame of the imaging region in D14 (hereinafter, referred to as D14
Simply described as "electronic type"), and the prism 35 shown in FIG.
There is a method of adjusting the optical axis angle of the incident light (hereinafter, simply referred to as “optical type”), and both of them detect shake by a shake sensor and make a correction according to the value.

First, the electronic type will be described with reference to FIG.
As shown in (a), the CCD 14 used electronically has a large area A0 whose image pickup area has more horizontal scanning lines than the video standard of the television. In an actual image, an area A1 having a horizontal scanning line conforming to the standard is cut out from the area A0 and used as an image signal. At this time, the area A1 is divided into, for example, the area A2 or the area A3 in accordance with the camera shake detection signal. As shown in the figure, the image is cut out by moving within the area A0 so as not to cause the shake on the CCD 14, and the shake of the image due to the hand shake is corrected.

FIG. 1 shows the electronic image stabilization function.
This will be described with reference to 3 (b). Here, considering the vertical direction, the focal length of the imaging lens 15 is f, the area A
The side 1 is 2h0 and the side of the area A0 is 2 (h + h0), and the correctable angle θ at this time is: tan (θ ₀ + θ) = (h + h0) / f (1) tan θ ₀ = h0 / F (2) θ ₀ + θ is small, so that θ ₀ + θ = (h + h ₀ ) / f (3) θ ₀ = h ₀ / f (4), so that θ = h / f (5) The angle can be determined.

If the CCD 14 is 2/3 inch, for example, the area A0 is 8.8 mm × 6.6 mm, and if the margin area for correction is approximately 30% in terms of the side ratio, it is 2.64 mm × 1. .98 mm. Therefore, the correction area on one side from the center is half of each, 1.32 mm
× 0.99 mm. At this time, when the focal length of the imaging lens 15 is f = 8 mm on the short focal length side, when focusing on the vertical direction, the correction angle θ is 0.99０．９8 ÷ 0.124 ra.
d ≒ 7 degrees and a large correctable angle can be obtained, but 0.99 ° when f = 200 mm on the long focal length side.
When it was 200 と 0.005 rad ≒ 0.28 degrees, there was a disadvantage that the correctable angle was extremely small. Of course, the same can be said for the horizontal direction.

Further, the CCD 14 must secure a large imaging area for correction, and the chip size becomes large and the CCD 14 becomes expensive. On the other hand, if a CCD conforming to the image standard is used, all pixels cannot be used, so that deterioration in image quality is inevitable.

Next, the optical system will be described. The principle of operation is as shown in FIG.
Is provided in the front part of the imaging lens 15 to change the apex angle of the prism 35 in accordance with a detection signal of camera shake and adjust the optical axis of incident light on the exit side.

That is, when the light L1 is perpendicularly incident on one surface of the prism 35 having the apex angle α, the emission angle of the light L2 emitted from the other surface is displaced by an angle θ with respect to the incident optical axis. That is, assuming that the refractive index of the prism 35 is n, nsinα = sin (α + θ) (6) Since α + θ is small, nα = α + θ (7), and therefore θ = (n−1) α (8). Here, for example, when n = 1.5 and α is displaced by ± 2 degrees, the deflection angle δ can be changed by ± 1 degrees.

Next, a conventional VAP element having a variable apex angle will be described with reference to FIG. 15. Two plate glasses 30a and 30 are opposed to each other with an arbitrary distance on the optical axis L.
b is arranged, and the outer peripheries of the two glass sheets 30a and 30b are connected by a bellows sealing member 32 having a bellows shape which can be extended and contracted to form a sealed space inside. An optical element, that is, a prism is formed by filling the sealed space with a transparent liquid, and the apex angle of the prism is turned around a shaft 34 provided on at least one of the two glass sheets 30a and 30b. It changes by moving. In addition, the sheet glass 30a, 30b and the bellows sealing member 32 are covered with a cover 3 to secure the sealing property.
1a and 31b.

The operation of the above-mentioned VAP element is shown in FIG. 16, in which the plate glass 30a and 30b are parallel to each other, and the incident light goes straight along the incident optical axis L and remains as it is. Emit. FIG. 2B shows a case where one plate glass, for example, the plate glass 30a is rotated and tilted about the shaft 12 and has an angle α between the plate glass 30a and the plate glass 30b (that is, the apex angle α). At this time, as described above, when the light L1 vertically incident on the plate glass 30b is emitted from the plate glass 30a, the light L2 is inclined by θ = (n-1) α degrees with respect to the incident optical axis, and the optical axis is changed. Will be done.

However, in the above-described VAP element, the bellows sealing member 32 is deformed by the mass of the liquid 33, making it difficult to keep the sheet glass in the initial position, and moving the liquid to change it into a wedge shape. Therefore, a large driving force is required, the response is inferior, and the volume changes due to the temperature change of the environment, the viscous resistance changes,
Therefore, there has been a problem that the control characteristics change.

FIG. 17 shows another example in which the apex angle is variable, and FIG. 17A shows this structure. Plano-concave lens 40
And the plano-convex lens 41, and the plano-concave lens 40 and the plano-convex lens 41 having substantially the same curvature are opposed to each other with a slight gap 35 provided between the concave surface and the convex surface of the plano-convex lens 41. The plano-convex lens 41 is held by an arm 42 that rotates about a shaft 44 in a direction indicated by an arrow R, and a rotary actuator 43.
It is rotated by the driving force of. Its turning radius is plano-convex lens 4
It is matched with the curvature of the convex surface of 1.

In FIG. 17B, the plano-convex lens 41 is rotated in the clockwise direction of the arrow R about the shaft 44, and the plano-concave lens 40 is rotated.
When the angle α occurs between the plane of the plano-convex lens 41 and the plane of the plano-convex lens 41, the light L1 which is perpendicularly incident on the plane of the plano-concave lens 40 at this time is emitted from the plane of the plano-convex lens 41 as in the VAP element. The light L2 is inclined by θ = (n-1) α degrees with respect to the incident optical axis, and the optical axis is converted.

In the variable apex angle prism of the type using the lens described above, in order to avoid contact between the plano-concave lens 40 and the plano-convex lens 41, which are opposed to each other, in consideration of manufacturing precision, mechanical configuration precision, and the like. You have to make a gap,
Therefore, there are problems that the third-order aberration is increased and that ghost is generated due to reflection on the boundary surface.

[0017]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image stabilizing optical device having high image quality, high-speed response and high stability, which eliminates the above-mentioned drawbacks of the image stabilizing element and mechanism. It is what

[0018]

Therefore, the present invention has been made in view of the above problems, and includes a concave lens and a convex lens, a first lens group having a positive combined focal length, a concave lens and a plate glass. Alternatively, a concave lens and a second lens group having a negative combined focal length are arranged in an ahocal system, and the concave lens of the second lens group is arranged perpendicular to the optical axis. A camera shake correction optical device is configured by providing a means for driving in two axial directions orthogonal to each other in a plane.

The absolute value of the product of the conversion magnification determined by the ratio of the combined focal length of the first lens group and the combined focal length of the second lens group, and the focal length of the concave lens of the second lens group. In order to solve the above problems, the optical image stabilization optical device is configured so that the ratio is 300 or more and 450 or less.

A camera-shake correction optical device that also serves as a teleside converter is provided. By mounting this optical-camera device on an image pickup device, an image shake caused by camera shake, particularly an image shake on the telephoto side, which is greatly affected by camera shake, is provided. Effectively correct.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a configuration of an image stabilizing optical device according to the present invention, and FIG. 2 is a diagram showing an entire image pickup optical system when the optical device is attached to an image pickup apparatus. FIG. 3 is a schematic perspective view showing the structure of a camera shake correction apparatus using the camera shake correction optical apparatus according to the present invention, and FIG. 4 is a block diagram of a control circuit of the camera shake correction apparatus using the camera shake correction optical apparatus according to the present invention. . 5 to 12 are aberration diagrams of the image stabilizing optical device.

In the correction of camera shake according to the present invention, an optical system for correcting a fluctuation of an incident optical axis by moving a lens is provided inside a teleside converter (telephoto optical system) for increasing an image pickup magnification, and a camera shake detection signal is received. The position of the lever is controlled so that the image is not shaken on the image pickup element, and the camera shake is effectively corrected.

First, the structure of the image stabilizing optical device will be described with reference to FIG. The lens system of this apparatus is composed of a first lens group 1a arranged on the object side and a second lens group 1b arranged immediately before the imaging lens. The first lens group 1a is composed of a convex lens G1 and a concave lens G2, which are attached to each other or slightly separated from each other.
The composite focal length has a positive value. The second lens group 1b is composed of a concave lens G3 and a concave lens G4, and the combined focal length has a negative value. The concave lens G4 may have a flat plate shape in view of the overall optical design.

Further, the image stabilizing optical device also constitutes a teleside converter, the lens systems of both groups are arranged so as to be ahocal, and the conversion magnification thereof is the ratio of the focal lengths of both groups. is there.

Although the camera shake correction will be described in detail later, it is performed by independently moving the concave lens G3 of the second lens group 1b in two orthogonal axial directions in a plane perpendicular to the optical axis L. .

FIG. 2 shows the entire optical system when the above-mentioned image stabilizing optical device 1 is mounted immediately in front of the main image pickup lens 2 of the conventional image pickup device. An image with no image is formed and converted into a video signal.

Next, preferable conditions of the optical system of the image stabilizing optical device 1 will be described. Condition 1 With the focal length of the main image pickup lens 2 being 100 mm, the amount of movement of the concave lens G3 of the second lens group 1b with respect to the first lens group 1a is set to obtain an image movement of 1.5 mm on the image pickup device 3. Must be within 5 mm.

Condition 2 When the product of the conversion magnification and the focal length of the concave lens G3 is X, the absolute value | X | is 450> | X |> 300 (9).

If the condition 1 is not satisfied, the amount of movement of the concave lens G3 increases, a large driving force is required for the movement, and high-speed response becomes difficult. In addition, the condition 2 is not satisfied,
If the inequality in equation (9) shifts to the larger side, the concave lens G3 must be made larger, while if it shifts to the smaller side, coma, astigmatism, chromatic aberration, etc. increase.

FIG. 3 is a perspective view of an entire image pickup optical system using the above-described image stabilization optical device. An image stabilizing optical device composed of a first lens group 1a composed of a convex lens G1 and a concave lens G2 and a second lens group 1b composed of a concave lens G3 and a lens G4 is provided at the front of the main imaging lens 2 of the imaging device. The lens group 1b is mounted with the main imaging lens 2 side. The object to be photographed is imaged on the image sensor 3 and converted into a video signal. The concave lens G3 has an X-axis actuator 10
And a Y-axis actuator 11 is attached,
Based on the detection results of the X-axis camera shake sensor 4 and the Y-axis camera shake sensor 5, the X-axis actuator 10 and the Y-axis actuator 11 are driven to make the position of the concave lens G3 orthogonal to the plane perpendicular to the optical axis L. By controlling in two axial directions, the object to be imaged is imaged without shaking.

FIG. 4 is a block diagram showing an example of the driving mode of the concave lens G3. The concave lens G3 is driven by a driving device 9 so as to be movable in the X-axis direction and the Y-axis direction in a plane perpendicular to the optical axis.
Is held in. The detection outputs of the X-axis camera shake sensor 4 and the Y-axis camera shake sensor 5 which are provided in the body of the image capturing apparatus for detecting the camera shake are input to a control circuit 6 which is composed of a CPU and the like. The movement control amount of the concave lens G2 is calculated, and the result is input to the X-axis and Y-axis drive mechanism portions of the drive device 9 via the X-axis drive circuit 7 and the Y-axis drive circuit 8. This allows the concave lens G
The XY position of 3 is controlled to adjust the optical axis of the incident light to the image pickup optical system, and as a result, the shake of the image on the image pickup element 3 does not occur.

Although the X-axis and Y-axis drive mechanisms are schematically shown as voice coil types, it goes without saying that other drive configurations that perform similar operations may be adopted. Further, the camera shake detection is not limited to the angular velocity sensor and the acceleration sensor, and a method obtained by image comparison with the immediately preceding frame image may be used.

Next, four embodiments of the optical system of the present invention will be described with reference to Tables 1 to 5 and FIGS. 5 to 12. Here, r represents the radius of curvature, and d represents the thickness of the lenses on the optical axis or the distance between the lenses. Further, nd is a refractive index in the spectrum d line, and Abbe number Vd is a number represented by Vd = (nd-1) / (nF-nC) (11), where nF and nC are spectrum F, respectively. Line and C line.

Embodiment 1 Table 1 shows an optical configuration of Embodiment 1.

[Table 1] From the data in Table 5, the amount of movement of the concave lens G3 for obtaining an image movement of 1.5 mm on the image sensor 3 is 4.78 mm, which satisfies the condition 1, and | X | is 399.1, which is the condition 2. Are satisfied.

Further, FIG. 5 is a diagram showing aberrations when the concave lens G3 is in the correct optical axis position in the lens structure of the first embodiment. In the figure, (a) is the diagonal position, (b) is the position 70% from the diagonal position, and (c) is the Y at the center position.
The lateral aberration DY in the direction is shown in FIG. 6D as a diagonal position, in FIG. 7E as a position 70% from the diagonal position, and as in FIG. Yes, in addition, (g)
Is the astigmatism AS in the sagittal direction S and the tangential direction T. In the figure, numbers 1, 2 and 3 are wavelengths 587, 56 nm, 435, 84 nm, 656 and 27 n, respectively.
It is a value in m, and is the same in the following. FIG.
FIG. 6A is an aberration diagram when the concave lens G3 is moved under the same conditions as in FIG. 5 to cause a shift of 1.5 mm in the imaging plane. (A) to (g) in FIG. 6 are (a) to (g) in FIG.
It relates to the same aberration as (g).

From FIGS. 5 and 6, when the concave lens G3 is moved, a slight increase in aberration is recognized, but it is sufficient for practical use, and since Condition 1 and Condition 2 are satisfied, this example is as follows. It can be seen that it is suitable for use in an image stabilizing optical device.

Embodiment 2 Table 2 shows the optical configuration of Embodiment 2.

[Table 2] From the data in Table 5, the amount of movement of the concave lens G3 for obtaining an image movement of 1.5 mm on the image pickup element 3 is 4.08 mm, which satisfies the condition 1, and | X | is 381.3 and the condition 2 is satisfied. Are satisfied.

Further, FIG. 7 is a diagram showing aberrations when the concave lens G3 is in the correct optical axis position in the lens structure of the second embodiment. In the figure, (a) is the diagonal position, (b) is the position 70% from the diagonal position, and (c) is the Y at the center position.
The lateral aberration DY in the direction is shown in FIG. 6D as a diagonal position, in FIG. 7E as a position 70% from the diagonal position, and as in FIG. Yes, in addition, (g)
Is the astigmatism AS in the sagittal direction S and the tangential direction T. Further, FIG. 8 is an aberration diagram when the concave lens G3 is moved under the same conditions as in FIG. 7 to cause a shift of 1.5 mm in the image forming surface. (A) in FIG.
(G) relates to the same aberrations as (a) to (g) of FIG. 7.

From FIGS. 7 and 8, when the concave lens G3 is moved, a slight increase in aberration is recognized, but it is sufficient for practical use, and since Condition 1 and Condition 2 are satisfied, this example is as follows. It can be seen that it is suitable for use in an image stabilizing optical device.

Embodiment 3 Table 3 shows the optical configuration of Embodiment 3.

[Table 3] From the data in Table 5, the amount of movement of the concave lens G3 for obtaining an image movement of 1.5 mm on the image pickup element 3 is 4.90 mm, which satisfies the condition 1, and | X | is 408.5 and the condition 2 is satisfied. Are satisfied.

Further, FIG. 9 is a diagram showing aberrations when the concave lens G3 is at the correct optical axis position in the lens structure of the second embodiment. In the figure, (a) is the diagonal position, (b) is the position 70% from the diagonal position, and (c) is the Y at the center position.
The lateral aberration DY in the direction is shown in FIG. 6D as a diagonal position, in FIG. 7E as a position 70% from the diagonal position, and as in FIG. Yes, in addition, (g)
Is the astigmatism AS in the sagittal direction S and the tangential direction T. Further, FIG. 10 is an aberration diagram when the concave lens G3 is moved under the same conditions as in FIG. 9 to cause a shift of 1.5 mm in the image plane. (A) in FIG.
(G) relates to the same aberrations as (a) to (g) of FIG. 9.

From FIGS. 9 and 10, when the concave lens G3 is moved, a slight increase in aberration is recognized, but it is sufficient for practical use, and since Condition 1 and Condition 2 are satisfied, this example is as follows. It can be seen that it is suitable for use in an image stabilizing optical device.

Embodiment 4 Table 4 shows an optical configuration of Embodiment 4.

[Table 4] From the data in Table 5, the amount of movement of the concave lens G3 for obtaining an image movement of 1.5 mm on the image sensor 3 is 3.83 mm, which satisfies the condition 1, and | X | is 325.2 and the condition 2 is satisfied. Are satisfied.

Further, FIG. 11 is a diagram showing aberrations when the concave lens G3 is at the correct optical axis position in the lens structure of the second embodiment. In the figure, (a) is the diagonal position, (b) is the position 70% from the diagonal position, and (c) is the Y at the center position.
The lateral aberration DY in the direction is shown in FIG. 6D as a diagonal position, in FIG. 7E as a position 70% from the diagonal position, and as in FIG. Yes, in addition, (g)
Is the astigmatism AS in the sagittal direction S and the tangential direction T. Further, FIG. 12 is under the same condition as FIG.
FIG. 9 is an aberration diagram when the concave lens G3 is moved so as to cause a shift of 1.5 mm on the imaging plane. (A) in FIG.
11A to 11G relate to the same aberrations as FIGS.

From FIGS. 11 and 12, when the concave lens G3 is moved, a slight increase in aberration is recognized, but this is sufficient for practical use, and since Condition 1 and Condition 2 are satisfied, this example is as follows. It can be seen that it is suitable for use in an image stabilizing optical device.

Table 5 shows the focal length of the concave lens G3 of each embodiment and the calculated values for the conditions 1 and 2.

[Table 5]

[0047]

As described above, by attaching the image stabilizing optical device which also functions as the teleside converter of the present invention to the image pickup device,
It is possible to effectively correct image blurring due to camera shake, particularly where the focal length is long where the effect of camera shake is large, that is, on the telephoto side, and it is possible to obtain a high quality image.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an image stabilization optical device according to the present invention.

FIG. 2 is a diagram showing the entire image pickup optical system when the image stabilizing optical device according to the present invention is attached to the image pickup apparatus.

FIG. 3 is a schematic perspective view showing the configuration of a camera shake correction device using the camera shake correction optical device according to the present invention.

FIG. 4 is a block diagram of a control circuit of a camera shake correction apparatus using the camera shake correction optical apparatus according to the present invention.

FIG. 5 is a concave lens G3 having the lens configuration according to the first embodiment.
FIG. 7 is a diagram showing aberrations when is at the correct optical axis position.
(A) is the diagonal position, (b) is the position 70% from the diagonal position, (c) is the lateral aberration DY in the Y direction at the center position,
(D) is the diagonal position, (e) is the 70% position from the diagonal position, (f) is the lateral aberration DX in the X direction at the center position,
Further, (g) is the astigmatism AS in the sagittal direction S and the tangential direction T. In the figure, numbers 1, 2 and 3 are wavelengths 587, 56 nm, 435, 84 nm and 6 respectively.
The values at 56 and 27 nm.

FIG. 6 is an aberration diagram when the concave lens G3 is moved under the same conditions as in FIG. 5 to cause a shift of 1.5 mm on the image forming surface.

FIG. 7 is a concave lens G3 having the lens configuration according to the second embodiment.
FIG. 7 is a diagram showing aberrations when is at the correct optical axis position. Other conditions are the same as those in FIG.

FIG. 8 is an aberration diagram when the concave lens G3 is moved under the same conditions as in FIG. 7 to cause a shift of 1.5 mm in the image plane.

FIG. 9 is a concave lens G3 having the lens configuration according to the third embodiment.
FIG. 7 is a diagram showing aberrations when is at the correct optical axis position. Other conditions are the same as those in FIG.

FIG. 10 is an aberration diagram when the concave lens G3 is moved under the same conditions as in FIG. 9 to cause a shift of 1.5 mm in the imaging plane.

FIG. 11 is a concave lens G having the lens configuration according to the fourth embodiment.
It is a figure which shows the aberration when 3 is in a correct optical axis position.
Other conditions are the same as those in FIG.

FIG. 12 is an aberration diagram when the concave lens G3 is moved under the same conditions as in FIG. 11 to cause a shift of 1.5 mm in the image forming surface.

13A and 13B are views for explaining a conventional electronic image stabilization mechanism, wherein FIG. 13A shows a frame for cutting out an image on a CCD, and FIG. 13B shows an optical axis corresponding to the frame for cutting out an image. The calculation of a correction angle is shown.

FIG. 14 is a diagram for explaining a conventional optical image stabilization mechanism.

FIG. 15 is a diagram showing a configuration of a VAP element.

FIG. 16 is a diagram showing an operation of the VAP element.

FIG. 17 shows a conventional image stabilization mechanism using a plano-concave lens and a plano-convex lens, wherein (a) is a configuration of an optical system,
(B) shows the operating state.

[Explanation of symbols]

 1 Shake Correction Optical Device 1a 1st Lens Group 1b 2nd Lens Group 2 Main Imaging Lens 3 Imaging Device 4 X-axis Shake Sensor 5 Y-axis Shake Sensor 6 Control Circuit 7 X-axis Drive Circuit 8 Y-axis Drive Circuit 9 Drive Device 10 X Axis actuator 11 Y-axis actuator 14 CCD 15 Imaging lens 30a, 30b Plate glass 31a, 31b Cover 32 Bellows sealing member 33 Liquid 34 Axis 35 Prism 40 Plano-concave lens 41 Plano-convex lens 42 Arm 43 Rotation actuator 44 Axis 45 Gap

Claims (2)

[Claims] 1. A first lens group composed of a concave lens and a convex lens and having a positive composite focal length, and a second lens group composed of a concave lens and plate glass or a concave lens and having a negative composite focal length. Is arranged to form an ahocal system, and means for driving the concave lens of the second lens group in two axial directions orthogonal to each other in a plane perpendicular to the optical axis is provided. Optical image stabilization device. 2. The product of the conversion magnification determined by the ratio of the combined focal length of the first lens group and the combined focal length of the second lens group, and the focal length of the concave lens of the second lens group. The optical image stabilizer according to claim 1, wherein an absolute value is 300 or more and 450 or less.