JPH10104678A - Apex angle variable prism and shake correction device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the correction of camera shake by simple structure and to constitute a device to be an adapter type. SOLUTION: An apex angle variable prism 22Y is constituted of a piano-concave lens 36 and a convexo-plane lens 35 and an apex angle variable prism 22X is constituted of a piano-concave lens 37 and a convexo-plane lens 38. The lens 36 is turned in a vertical direction and the lens 37 is turned in a horizontal direction. When the turning angles thereof are synthesized, the movement of an optical axis becomes two-dimensional. When the lens is turned, the apex angle of the prism is changed and the transmitted optical axis thereof is varied. Since a guide means for turning the optical lenses in the direction of a curvature surface is arranged between the optical lenses by the curvature of an identical curvature center, the first and the second lenses are extremely smoothly turned with respect to the second and the fourth lenses. When the optical axis of the specified lens is varied based on an sensor output obtained at the detecting time of the shake of a video camera, the camera shake can be corrected. Since the optical lens is cylindrical, control accuracy is high because the optical axis is not changed in the turning axis direction of the lens even when the lens is deviated in the turning axis direction thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertex angle variable prism suitable for application to a camera shake correction in which the optical axis angle can be varied, and a shake correction apparatus using the same. Specifically, a pair of variable apex angle prisms, which form an afocal optical system by combining two optical lenses that are close to and opposed to each other with an uneven surface having almost the same radius of curvature with a certain gap, are arranged on the optical axis. The transmitted optical axis can be changed with a simple configuration by changing the optical axis (horizontal axis and vertical axis) of one of the optical lenses provided and changing the apex angle of the prism. is there. The shake correcting apparatus uses the variable apex angle prism to easily correct angular shake such as camera shake.

[0002]

2. Description of the Related Art In recent years, in order to control that a photographed image fluctuates due to vibration transmitted to a camera when photographing a television camera,
A camera that detects the camera's angular attitude is mounted inside the camera, and the vertex angle of the camera shake correction prism placed on the optical path of the camera shooting lens is changed according to the output, thereby tilting the transmitted optical axis and tilting the camera. 2. Description of the Related Art There is known a camera shake correction device that cancels image shake caused by an image.

[0003] For example, in Japanese Patent Application Laid-Open No. 61-269572, a special liquid is sandwiched between plate glasses in a lens optical axis, and the apex angle of a prism is changed by changing the angular orientation of one of the plate glasses. Thereby, the transmitted light axis is corrected by the angle of the camera shake.

On the other hand, a plano-convex lens and a plano-concave lens having the same refractive index and curvature are used so that their spherical surfaces keep a slight gap,
By rotating one lens along the spherical surface,
An apex angle variable prism using a concavo-convex lens that changes the angle formed by two planes facing each other across a spherical surface has also been devised as a camera shake correction device. "JP-A-6-070220
Japanese Patent Application Laid-Open Publication No. Hei 6-2 discloses a vertex angle variable prism using a concave-convex lens as a camera shake correction device.
No. 81889 discloses a vertex angle variable prism using a concave-convex lens as a camera shake correction device.

[0005]

In the above-described liquid-encapsulated apex angle variable prism, since the liquid is sealed between the two sheets of glass and the bellows connecting them, when the angle of the sheet glass is changed. However, there is a drawback that this liquid acts as a viscous resistance and it is difficult to follow high-speed vibration.

On the other hand, an apex angle variable prism using a concavo-convex lens combination method is described as a known technique in Japanese Patent Publication No. 57-25803, but has not been widely used to date. The reason is that
As described in Japanese Patent Application Laid-Open No. 7-25803, the curvature of the concave / convex lens cannot be reduced so much that it cannot be held rotatably around the center of curvature in a narrow space. This is because, when sliding and moving on a spherical surface having the same center, it is expected that the sliding will deteriorate the responsiveness of the swing and the sliding portion will be damaged.

[0007] In fact, as described in Japanese Patent Laid-Open No. 6-281889,
The method of supporting the rotation of the convex lens invented in
An axis parallel to the imaging surface and passing through the center of curvature of the convex lens is formed outside the lens, and the arm formed rotatably on this axis holds the convex lens to support the rotation of the convex lens.

[0008] For this reason, similar to the method of swinging the entire image pickup system, there is a disadvantage that the rotating part becomes large and the whole apparatus becomes large. In addition, since the moving part is heavy, the inertia becomes large and the speed becomes high. Has poor drawbacks with respect to vibrations and requires a large amount of energy.

The present invention solves such a conventional problem, and employs a pair of afocal variable apex angle prisms configured by combining two optical lenses.
In addition to forming a three-dimensional apex angle variable prism, a rotating means for the optical lens is realized with a simple structure. In addition, a shake correction device using such a variable apex angle prism can accurately perform two-dimensional correction such as camera shake correction.

[0010]

According to the first aspect of the present invention, there is provided a variable apex angle prism according to the present invention, comprising: a first optical lens having a first surface and a second surface;
An apex angle variable prism configured by a second optical lens including a third surface and a fourth surface and arranged close to each other;
The second surface is a cylindrical surface having a predetermined curvature, and the third surface is
The surface is a cylindrical surface having the same sign as the second surface and having a curvature approximately similar to the second surface, and the center axes of curvature of the second surface and the third surface are the same as those of the first or second optical lens. The variable focal length prism is characterized in that the overall focal length is afocal.

In the shake correcting apparatus according to the present invention, the first optical lens having the first surface and the second surface and the second optical lens having the third surface and the fourth surface are arranged close to each other. A prism having a variable apex angle, wherein the second surface is a cylindrical surface having a predetermined curvature, and the third surface is a cylindrical surface having the same sign as the second surface and having a curvature approximately similar to the second surface. ,
The center axis of curvature of the second surface is the rotation center axis of the first optical lens, the center axis of curvature of the third surface is the rotation center axis of the second optical lens, and the angle An apex angle variable prism designed so that the combined focal length of the entire variable prism is an afocal system.The apex angle variable prism is attached to an optical system of a video camera as a shake correction mechanism, and is attached to a lens barrel thereof. Is provided with an angular velocity sensor to detect the shake of the video camera, and based on the detected shake component, the first optical lens with respect to the second optical lens.
The rotation angle of the second optical lens relative to the first optical lens or the first optical lens is changed, so that the apex angle of the apex angle variable prism is varied and the transmission optical axis thereof is changed. And

According to a tenth aspect of the present invention, a vertex angle variable prism includes a first optical lens having a first surface and a second surface, and a second optical lens having a third surface and a fourth surface. A first apex angle variable prism arranged in close proximity to each other, a third optical lens comprising a fifth surface and a sixth surface,
A second apex angle variable prism is composed of a fourth optical lens composed of a seventh surface and an eighth surface, and a second apex angle variable prism is disposed in proximity to each other, and the second apex angle variable prism is formed. The third surface is a cylindrical surface having the same sign as that of the second surface and has a curvature approximately similar to the second surface, and the sixth surface is a cylindrical surface having a predetermined curvature. Made
The seventh surface has the same sign as that of the sixth surface and has a substantially cylindrical surface of curvature similar to that of the sixth surface, and the center axes of curvature of the second and third surfaces are the same as those of the first or second surface. The rotation center axis of one of the optical lenses is defined as the rotation center axis of the sixth and seventh surfaces, and the rotation center axis of one of the third and fourth optical lenses is defined as the rotation center axis of the third or fourth optical lens. And the respective rotation directions are selected so that the respective rotation surfaces are orthogonal to each other, and the combined focal length of the entire first and second apex angle variable prisms is an afocal system. And

In the image stabilizing apparatus according to the nineteenth aspect of the present invention, the first optical lens including the first surface and the second surface and the second optical lens including the third and fourth surfaces are used. A first apex angle variable prism that is configured and arranged close to each other, a third optical lens including a fifth surface and a sixth surface,
A second apex angle variable prism is constituted by a second apex angle variable prism composed of a fourth surface and a fourth optical lens composed of an eighth surface, and a second apex angle variable prism arranged close to each other, and the second surface has a predetermined curvature. The third surface is a cylindrical surface having the same sign as the second surface, with the same sign as the second surface, and is approximately the same as the second surface. The sixth surface is a cylindrical surface having a predetermined curvature, and the seventh surface is the sixth surface. The surface has the same sign as that of the surface, and has a curvature cylindrical surface approximately similar to the sixth surface, and the center of curvature of the second surface and the third surface is the rotation center of one of the first and second optical lenses. And the sixth
The center axes of curvature of the surface and the seventh surface are defined as the rotation center axis of one of the third and fourth optical lenses, and the respective rotation directions are set so that the respective rotation surfaces are orthogonal to each other. A variable apex angle prism selected and designed such that the combined focal length of the first and second apex angle variable prisms as a whole is an afocal system, and the apex angle variable prism is a video camera as a shake correction mechanism. The lens barrel is provided with an angular velocity sensor, and the shake of the video camera is detected. Based on the detected shake component, the first and second optical lenses with respect to the second and fourth optical lenses are detected. The apex angle of the apex angle variable prism is changed by controlling the rotation of one or both of the second optical lens and the second and fourth optical lenses with respect to the first and third optical lenses. Wherein the transmission optical axis is made to be changed.

According to the present invention, when the apex angle variable prism is constituted by a pair of optical lenses, the optical axis in one of the horizontal and vertical directions can be changed. On the other hand, by using a pair of apex angle variable prisms constituted by a pair of optical lenses, two orthogonal optical axes can be independently changed. A cylindrical lens is used as the apex angle variable prism.

For example, when using a pair of variable apex angle prisms disposed close to each other on the same optical path, each prism is composed of two optical lenses, and the surfaces of the two optical lenses which oppose each other are predetermined. It is a cylindrical surface having a radius of curvature. In one apex angle variable prism, one optical lens is made rotatable, for example, in the vertical direction (Y-Y axis) to change the angle of the transmitted light axis in the vertical direction. On the other hand, the other apex angle variable prism is also 1
The optical lenses are rotatable in the horizontal direction (the X-X 'axis), so that the angle of the transmitted light axis in the horizontal direction can be changed. Therefore, by combining these, the angle of the entire transmission optical axis can be changed in an arbitrary direction (on polar coordinates).

Since guide means for rotating in the direction of the curvature surface are arranged between the first and second optical lenses and between the third and fourth optical lenses, for example, the second The rotation of the first optical lens with respect to the optical lens and the rotation of the fourth optical lens with respect to the third optical lens become extremely smooth. Further, since the configurations of the guide means and the lens driving means are very simple, the rotation angle control becomes accurate and the driving power can be reduced.

If a sensor output due to camera shake of a video camera is divided into horizontal and vertical components, and a correction signal generated based on this is given as, for example, a rotation control signal for the first and third optical lenses, a camera shake due to camera shake is provided. Screen shake can be easily corrected.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a video camera equipped with a variable apex angle prism and a shake correcting device having the variable apex angle prism according to the present invention.

FIG. 1 shows an embodiment of a video camera 10 for news gathering provided with a shake correction device having a variable apex angle prism. In this example, a subject 11 is an image pickup device via an optical system 12. The two-dimensional CCD 13 converts the light image of the subject into an electric signal (imaging signal). The imaging signal is converted into a composite or component color video signal in a signal processing unit 14 at the subsequent stage, and is derived to a terminal 15.

In front of the optical system 12, a shake correcting mechanism 20 is mounted. The shake correction mechanism unit 20 is configured in an adapter type, and is configured to be detachable from the video camera 10. Therefore, it is connected to the optical system 12 only when necessary.

The shake correcting mechanism section 20 is composed of a variable apex angle prism. The shake correction mechanism unit 20 can also be configured using one variable apex angle prism configured with a pair of optical lenses (cylindrical lenses). In this case, it is used to correct only the shake in one direction (for example, the vertical axis direction).

As an example of such use, for example, a video camera installed outdoors can be cited. The camcorder is mounted on a solid platform that does not shake. Therefore, the countermeasures against the horizontal (horizontal) vibration are complete, but the countermeasures against the vibration in the vertical direction (vertical direction) are inadequate because a person rides on the table. Therefore, in a video camera used in such a place, only the vertical shake needs to be considered.

On the other hand, the shake correcting mechanism section 20 can be constituted by using two apex angle variable prisms constituted by a pair of optical lenses. In this case, for example, the shake in any direction can be corrected by correcting the optical axis with respect to the two axes of the vertical axis direction and the horizontal axis direction. FIG. 1 illustrates an example in which the shake correction mechanism unit 20 is configured using a pair of apex angle variable prisms.

As shown in FIG. 1, the shake correction mechanism section 20 has first and second apex angle variable prisms 22X and 22Y arranged in front and behind on an optical path. These are orthogonal two-axis configurations, and the first apex angle variable prism 22Y is for changing the optical axis in, for example, the vertical direction (Y-Y 'axis), and therefore, the second apex angle variable prism 22X Is for changing the optical axis in the horizontal direction (XX 'axis). Further, in this example, an angular velocity detector (sensor) 23 is attached to the lens barrel 21X of the second apex angle variable prism 22X, and the shake (such as camera shake) of the video camera 10 is detected.

As shown in FIG. 2, the angular velocity detector 23 detects an angular velocity sensor 31 for detecting a vibration component in the horizontal direction (yaw direction, pan direction) x and a vibration component in the vertical direction (pitching direction, tilt direction) y. The one configured with the angular velocity sensor 32 can be used,
An angular velocity sensor 31 is attached to the lens barrel 21X so as to be parallel to the horizontal direction of the video camera 10.

The sensor 31 detects a vibration component △ x in the horizontal direction, and the other sensor 32 detects a vibration component △ y in the vertical direction. These are provided to a control unit 24 having a built-in CPU.

In the control unit 24, these vibration components {x, △
From y, the shake angle of the video camera 10 is calculated, and the swing angle control signals △ x ′ and △ y ′ are generated so that the swing angle can be corrected. These rotation angle control signals △ x 'and △ y' are supplied to corresponding control circuits 25 and 2 respectively.
8 and are supplied to the motor drivers 26 and 29 and applied to the corresponding drive motors 27 and 30.

Here, the drive motor 27 is a drive motor for rotating the fourth optical lens 38 provided on the second apex angle variable prism 22X, and the other drive motor 3
Reference numeral 0 denotes a drive motor for rotating the first optical lens 36 provided on the first apex angle variable prism 22Y, and a rotation angle θx corresponding to the values of the control signals △ x ′ and △ y ′. ,
Each of the optical lenses 36 and 38 is varied by θy.

Now, the apex angle variable prism 22 described above has two optical lenses (35, 36) and (37, 38).
And second vertex angle variable prisms 22Y, 22X having
It consists of. FIG. 3 shows an example of the first apex angle variable prism 22Y satisfying such a relationship. For example, when a plano-concave lens is used as the first optical lens 36, a convex-planar lens is used as the second optical lens 35.

The second surface G2 is a cylindrical surface having a predetermined curvature, and the third surface G3 is a cylindrical surface having substantially the same sign as that of the second surface G2. The central axes of curvature of the second surface G2 and the third surface G3 are parallel to each other. In close proximity. And it is designed so that the overall combined focal length becomes an afocal system. Details of the afocal system will be described later.

One of the first and second optical lenses 35 and 36, in this example, the first optical lens 36 is rotatable in the vertical direction (Y-Y 'axis) with its center axis of curvature being the center axis of rotation. The direction of the second surface G2 and the third surface G3 (the direction of the cylindrical surface) is determined so as to be as follows.

The second variable apex angle prism 22X has exactly the same configuration as the first variable apex angle prism 22Y, and includes a third optical lens 37 having a plano-concave lens configuration and a third optical lens 37 having a convex and flat lens configuration as shown in FIG. In this example, the third optical lens 37 is arranged such that the third optical lens 37 is in the horizontal direction with the center axis of curvature of the sixth surface as the center axis of rotation. The directions of the sixth surface G6 and the seventh surface G7 are determined so as to be rotatable around (XX 'axis). That is, the first
The second apex angle variable prism 22X is arranged on the optical path so as to be orthogonal to the apex angle variable prism 22Y. By using an afocal system, there is no effect on the optical image of the subject 11 entering the optical system 12.

The first apex angle variable prism 22Y shown in FIG.
Is mounted in a lens barrel 21Y as shown in FIG. FIG. 5 is a cross-sectional view parallel to the vertical axis (YY ') with respect to the optical axis, and the third surface G3 is located at the front of the rectangular tube 21Y having a predetermined length at substantially the center. So that the second optical lens 3
5 is attached and fixed.

A third surface G is provided on the front surface of the second optical lens 35.
The first optical lens 36 is attached so as to be rotatable in the vertical direction while maintaining a small gap between the first optical lens 36 and the third optical lens 36. Actually, the guide means 39 and the drive means 44 as shown in FIG. 6 are provided so that the second surface G2 can rotate in the YY 'direction in parallel with the third surface G3.

FIG. 6 is an exploded view as viewed from the upper side of FIG. 5, and a pair of guide grooves 40 and 41 are arranged in parallel near the left and right ends of the third surface G3 constituting the second optical lens 35. Arc guides 58 and 59 having sliding concave portions having a T-shaped cross section are fixed thereto. Guide 58,
59 protrudes from the third surface G3 by a predetermined length, whereby the distance between the first surface 59 and the second surface G2 can be determined.

On the other hand, on the second surface G2 side of the first optical lens 36, guide strips 42 and 43 having a T-shaped cross section are attached in a bow shape at positions facing the guides 58 and 59. (See FIG. 7), and the
The first optical lens 36 is rotated in the YY 'direction while maintaining a predetermined gap with respect to the second optical lens 35 by mounting the first optical lens 36a and the second 43a in the sliding concave portions of the guides 58, 59. be able to.

As described above, since the guide means 39 for rotating in the direction of the curvature surface is disposed between the first and second optical lenses 36 and 35 with the same curvature at the center of curvature, the second means is provided. First optical lens 3 with respect to optical lens 35
The rotation of 6 becomes very smooth. As a result, the rotation angle can be adjusted accurately. The configuration is also very simple. In most cases, the loads on the guide means 39 and 49 are the first and third optical lenses 36 and 38, so that the load is reduced, the rotation becomes smoother, and the rotation power is reduced.

An example of the driving means 44 for rotating the first optical lens 36 will be described with reference to FIGS. A pinion 45 is attached to the drive motor 46,
The pinion 45 meshes with the rack 47, and the power is transmitted to the first optical lens 36.

The meshing surface of the rack 47 is as shown in FIG.
The rack has substantially the same center of curvature as the second surface G2, and the rack body is attached to the side wall of the first optical lens. As a result, when the pinion 45 is rotated as shown in FIGS. 7 and 8, the first optical lens 36 can be rotated in the rotation direction. FIG. 8 is a diagram when the first optical lens 36 is viewed from the subject side,
As is clear from this figure, the first optical lens 36 is set to Y
It can be rotated by a predetermined angle in the -Y 'direction (vertical direction).

Since the second apex angle variable prism 22X has the same configuration, the corresponding portions are denoted by the corresponding reference numerals. As shown in FIG. 5, the third optical lens 37 is
Since the configuration and operation are exactly the same except that the optical lens 38 needs to be rotated in the horizontal direction (X-X 'direction) with respect to the optical lens 38, the configuration and operation are omitted. Grooves 50 and 51 and arc guide 5
2 and 53. The driving means 54 is also a driving motor 5
6, a pinion 55 and a rack 57.

FIG. 9 shows the mounting state of the first and second optical lenses 36 and 35 constituting the first apex angle variable prism 22Y when viewed from the upper side, and FIG. 9 when viewed from the side. B. FIG. 10 shows a second apex angle variable prism 2.
This is a 2X relationship, and is shown in FIG. A when viewed from the top side, and is shown in FIG. B when viewed from the side.

With respect to the shake correcting mechanism 20 constructed as described above, the apex angle variable prism 22 included therein
The combined focal length of X and 22Y is designed to be afocal. The conditions for that are as follows. The description will be made using the first and second optical lenses 36 and 35.

BK7 was used as the material of the optical lens.
The respective radii of curvature are all equal to R100 mm, and a gap of 1 mm is provided as the opposing gap △.
Then, as shown in FIG. 11, the concave and convex cylindrical surface having substantially the same radius is formed with a slight gap (refractive index n2: 1.516, for example).
33) In the variable apex angle prism (tablet lens) opposed by △, the radius of curvature of the second surface G2 is r1, the radius of curvature of the third surface G3 is r2, and the common refractive index of the two lenses 35 and 36 is n1. In this case, the design is made so as to satisfy (Equation 1).

[0044]

(Equation 1)

The radius of curvature r2 is given by r2 = (100 + 1) * (1.51633-1) = 100.51633. Now, a ray parallel to the optical axis enters the first surface G1 of the first optical lens (plano-concave lens) at a height y1, and enters the second surface G2 having a radius r1 at the same height at a point P1. If the angle between the ray and the normal on the cylindrical surface forms the optical axis, i1
Is the angle of incidence of this ray on the second surface G2. If the refraction angle of this ray is i2

[0046]

(Equation 2)

Using the paraxial ray approximation,

[0048]

(Equation 3)

Can be expressed as

Next, assuming that the angle between the refracted ray and the incident optical axis is i2,

[0051]

(Equation 4)

Is as follows. Further, the point at which this light ray enters the third surface (convex cylindrical surface) G3 of the second optical lens 35 is defined as P
2, if its height is y2,

[0053]

(Equation 5)

Assuming that the angle between the normal line of the third surface G3 and the optical axis at P2 is i4 and the radius of curvature is r2.

[0055]

(Equation 6)

Therefore,

[0057]

(Equation 7)

Here, i4 = i1, that is, the inclination of the normal to the first incidence surface and the inclination of the second incidence surface are equal, and both lenses 3
When the indices of refraction of 5 and 36 are equal, the ray has entered the two parallel interfaces from the medium with the index of refraction n1 to the medium of n2, and has returned to the medium of n1 again, and the ray keeps the original angle. Will be. Therefore, if (Equation 1) is satisfied, the coefficient of i1 in the above equation becomes 1, and the light beam enters the plane G4 of the second optical lens 35 perpendicularly while being parallel to the same optical axis as the incident light,
The light is emitted with the incident angle kept as it is. Therefore, the vertical shake correction mechanism 22Y is an optical system that satisfies the afocal system.

Next, the refractive index of the second optical lens 35
A case different from the optical lens 36 of FIG.

As shown in FIG. 12, the refractive index of the concave lens 36 is n1, the refractive index of air is n2, the radius of curvature of the third surface G3 is r2, and the refractive index of the convex lens 35 is n2.
Then, design is made so as to satisfy the following relationship between these numbers.

[0061]

(Equation 8)

In this case as well, the above holds up to (Equation 7). However, since the refractive indices of the two lenses 35 and 36 are different, even if the inclinations of the normal lines of the surfaces at the points P1 and P2 match. The outgoing ray is not parallel to the incident ray and the refraction at P2 must be examined. First, the incident angle at P2 is i5, and the refraction angle is i
Assuming 6,

[0063]

(Equation 9)

Accordingly, the angle i7 formed by the light beam refracting P2 and the optical axis can be expressed as follows.

[0065]

(Equation 10)

Here, if the value in [] of the above equation becomes 0, i7
= 0, the refracted light beam becomes parallel to the optical axis, and becomes parallel to the optical axis even after passing through the plane of the plano-convex lens. Since this parallel condition is satisfied if the condition of (Equation 8) is satisfied,
(Equation 8) is an afocal condition in the apex angle variable prism 22 in which a plano-convex lens and a plano-concave lens are combined.

When only the first optical lens 36 is changed in the vertical direction by θ as shown in FIGS. 13A to 13B, a prism having an apex angle of θ is formed, and the light beam on the first optical lens 36 side is only α. Bend. Therefore, according to Snell's law, when (n1 / n2) sin θ = sin (θ + α) θ is infinitely close to zero, (n1 / n2) θ = (θ + α) ∴α = ｛(n1 / n2) −1) θ Becomes Here, the refractive index n1 of the first optical lens 36
If n1 = 1.5, since the refractive index of air n2 = 1, α = 0.5θ. Therefore, when the first optical lens 36 is rotated and inclined by the angle θ, the output optical axis can be displaced by θ / 2. That is, when the optical axis is tilted by α in the vertical direction, the optical axis after camera shake can be corrected by tilting the first optical lens 36 by 2α in the direction opposite to the direction of the tilt.

The relationship between the third optical lens 37 and the fourth optical lens 38 is the same as described above, and when the optical axis is inclined by α in the horizontal direction, the direction is opposite to the direction of the inclination by 2 °.
By tilting the third optical lens 37 by α, the optical axis can be corrected. As a result, when the optical axis is two-dimensionally inclined, if the first and third optical lenses 36 and 37 are simultaneously rotated by a predetermined angle and inclined, two-dimensional optical axis correction can be realized.

Therefore, when the camera shake correction device is attached to the video camera 10 for camera shake correction as shown in FIG. 1, the control unit 24 executes the correction processing as shown in FIG.

As shown in the figure, the vibration components △ x 'and △ y' from the angular velocity sensor 23 are fetched (step 6).
1, 62), and then appropriate correction values △ x and △ y are calculated (steps 63, 64). The appropriate correction value is a control signal for obtaining a rotation angle sufficient to correct camera shake. The rotation angle control signals having the calculated appropriate correction values are supplied to the drive motors 27 and 30, respectively, to rotate the first optical lens 36 by an amount corresponding to Δy, and
Is rotated by an amount corresponding to Δx, and the optical axis is corrected by camera shake.

The cylindrical surfaces of the first to fourth optical lenses 35 to 38 may be completely opposite to those described above.
The concave / convex relationship of the second apex angle variable prism with respect to the apex angle variable prism may be selected to be the opposite relationship to the embodiment. That is, while the first variable apex angle prism 22Y remains the same as in FIG. 3, the configuration of the cylindrical lens forming the second variable apex angle prism 22X is reversed from that of FIG. The cylindrical lens may be used, and the fourth optical lens 38 may be a concave flat cylindrical lens.

On the contrary, instead of leaving the second variable apex angle prism 2X in the configuration shown in FIG. 4, the first optical lens 36 constituting the first variable apex angle prism 22Y is replaced by a plano-convex cylinder. As a lens, the second optical lens 35 can be configured as a concave flat cylindrical lens.

In the above description, a case has been described in which two axes orthogonal to each other of the optical lens are selected as the horizontal axis and the vertical axis. However, it is not necessary to use the two orthogonal axes coincident with these axes. Therefore, an axis inclined by an arbitrary angle from the horizontal axis and the vertical axis can be used as two orthogonal axes.

Each of the above-described variable apex angle prisms uses a cylindrical lens, and thus has the following features. (1) Even if the cylindrical lenses are displaced from each other in the direction of the lens rotation axis, their transmission optical axes do not change, so that the optical characteristics do not change. (2) Since the first and second apex angle variable prisms are independent of each other, the optical axis can be changed only in the Y-axis direction, for example, and no extra change occurs in the X-axis direction.
Therefore, the control accuracy of the two-dimensional angle is high, and no extra compensation processing is required. (3) Since the precision of the angle control with respect to the optical axis is high, the variable apex angle prism according to the present invention can be used not only for shake correction but also for a beam scanning system of a beam scanner, for example. In that case, a precise beam scanning system can be constructed. (4) When applied to a beam scanning system, even if there is play in the lens rotation axis direction, the optical axis does not change in the lens rotation axis direction. Is not required much. Therefore, the cost of the mechanism can be reduced. (5) Since a sufficient mechanical clearance can be provided in the lens rotation axis direction, the guide means in the lens rotation axis direction can have a very rough configuration. This simplifies the configuration of the guide system,
Load seen from drive motor (guide means and optical lens system)
Becomes lighter. If the load is light, high-speed driving can be performed, so that high-speed response is possible. Not only light load but also a power saving effect is produced, so that power saving can be achieved at the same time.

In the above-described example, the variable apex angle prism according to the present invention is applied to a camera shake correction system of a video camera. However, it is apparent that the present invention is not limited to this and can be applied to an optical axis correction system of a movie camera or a still camera. It is.

[0076]

As described above, according to the present invention, one apex angle variable prism combining two optical lenses having a cylindrical surface having a predetermined radius of curvature is used, or one pair is used, and a combination thereof is used. The focal lengths are arranged close to each other so as to form an afocal system, and the optical axis of a specific optical lens can be changed.

By using such a shake correcting device using the apex angle variable prism, the optical axis in the specific axis direction can be changed by using a single apex angle variable prism, and the specific axis direction can be changed. Can be easily corrected.

By using a pair of apex angle variable prisms, it is possible to change the optical axis only in the vertical axis direction or the optical axis only in the horizontal axis direction. Its optical axis can be changed in any direction. As a result, in the case of using a shake correction device using such a vertex angle variable prism, a two-dimensional (polar coordinate) shake can be easily corrected.

The plurality of optical lenses are provided with guide means, respectively. Since a cylindrical lens is used as the optical lens, the displacement of the cylindrical lens in the direction of the rotation axis does not affect its optical characteristics. . Therefore, a sufficient mechanical clearance can be provided in the lens rotation axis direction, and the guide means in the lens rotation axis direction can have a very rough configuration. As a result, the configuration of the guide system can be simplified, so that the load (guide means and optical lens system) viewed from the drive motor is reduced. If the load is light, high-speed driving can be performed, so that high-speed response is possible. Since light load produces a power saving effect, of course,
It has the feature that power saving can be achieved at the same time.

When the shake correction device is used in a video camera, the camera shake can be completely corrected. In addition, since the shake correction device can be used in an adapter type, it is not necessary to mount the shake correction device when it is not necessary. It has features such as being improved.

Accordingly, the present invention is extremely suitable for application to video cameras used for business use and news gathering, as well as video cameras and scanners for outdoor use of special purposes.

[Brief description of the drawings]

FIG. 1 is a system diagram of a main part showing an embodiment of a video camera provided with a shake correction mechanism using a variable apex angle prism according to the present invention.

FIG. 2 is a configuration diagram illustrating an example of an angular velocity sensor for shake detection.

FIG. 3 is a perspective view showing an example of a first apex angle variable prism among the apex angle variable prisms according to the present invention.

FIG. 4 is a perspective view showing an example of a second apex angle variable prism among the apex angle variable prisms according to the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of a main part of a shake correction apparatus according to the present invention.

FIG. 6 is a configuration diagram when an example of a pitching correction mechanism is viewed from above.

FIG. 7 is a diagram illustrating a driving unit of the first optical lens.

FIG. 8 is a front view of the first optical lens.

FIG. 9 is a diagram illustrating a lens relationship of a first apex angle variable prism.

FIG. 10 is a diagram showing a lens relationship of a second apex angle variable prism.

FIG. 11 is a view showing that the apex angle variable prism is an afocal system.

FIG. 12 is a diagram showing that the apex angle variable prism is an afocal system.

FIG. 13 is an explanatory diagram of an apex angle variable prism at the time of camera shake correction.

FIG. 14 is a flowchart illustrating an example for camera shake correction.

[Explanation of symbols]

10 video camera, 12 optical system, 13 ...
・ CCD, 20: shake correction mechanism, 22X, 22Y
... Variable angle prism, 22 ... Optical lens correction system, 35 ... Second optical lens, 36 ... First optical lens, 37 ... Third optical lens, 38 ... · Fourth optical lens, G1 to G8 ... first to eighth cylindrical surfaces

Claims (22)

[Claims] 1. A prism having a variable apex angle, which includes a first optical lens having a first surface and a second surface and a second optical lens having a third surface and a fourth surface, and is disposed close to each other. The second surface is a cylindrical surface having a predetermined curvature, and the third surface is
The surface is a cylindrical surface having the same sign as the second surface and having a curvature approximately similar to the second surface, and the central axis of curvature of the second surface and the third surface is the same as that of the first or second optical lens. A variable apex angle prism, wherein the variable focal length prism is an afocal system. 2. The variable apex angle prism according to claim 1, wherein the first optical lens or the second optical lens is relatively rotatable. 3. When the rotation axis of the first or second optical lens is set to a horizontal axis or a vertical axis, the first or second optical lens is prevented from moving in the vertical or horizontal axis direction. 2. The transmission optical axis of the variable apex angle prism is varied by rotating the vertical axis or the horizontal axis direction to vary the apex angle of the apex angle variable prism. Vertical angle variable prism. 4. When the first optical lens is a plano-concave cylindrical lens or a plano-convex cylindrical lens, the second optical lens is a convex plano-cylindrical lens or a concave plano-cylindrical lens. The variable apex angle prism according to 1. 5. A lens rotation guide means is provided between the second surface and the third surface, wherein the first optical lens is provided for the second optical lens or the first optical lens is provided for the first optical lens. 2. The apparatus according to claim 1, wherein the second optical lens is independently rotatable.
The apex angle variable prism described. 6. The optical system according to claim 5, wherein the first or second optical lens is provided with a drive unit connected to the guide unit, and the driving unit applies a rotating power to the corresponding optical lens. Apex angle variable prism. 7. The drive means comprises a pinion connected to a drive motor, and a rack meshing with the pinion and having a curvature at the center of curvature, wherein the rack is provided with the first optical lens or the first optical lens. 7. The variable apex angle prism according to claim 6, wherein the prism is attached to the second optical lens. 8. A variable apex angle prism in which a first optical lens having a first surface and a second surface and a second optical lens having a third surface and a fourth surface are arranged close to each other, and The second surface is a cylindrical surface having a predetermined curvature, the third surface is a cylindrical surface having the same sign as that of the second surface, and is substantially similar to the second surface, and a central axis of curvature of the second surface. Is the rotation center axis of the first optical lens, the curvature center axis of the third surface is the rotation center axis of the second optical lens, and the combined focal length of the entire angle variable prism is An apex angle variable prism designed to be an afocal system. The apex angle variable prism is attached to an optical system of a video camera as a shake correction mechanism, and an angular velocity sensor is disposed in a lens barrel of the video camera. Camera shake detected, detected Re based on the component, by controlling rotation of the second optical lens for the first optical lens or the first optical lens to said second optical lens,
A shake correcting apparatus, wherein the apex angle of the apex angle variable prism is varied to change the transmitted optical axis. 9. The shake correction apparatus according to claim 8, wherein the shake correction mechanism is configured to be detachable from the optical system. 10. A first apex angle, comprising a first optical lens having a first surface and a second surface and a second optical lens having a third surface and a fourth surface, which are arranged close to each other. A variable apex, a third optical lens including a fifth surface and a sixth surface, and a fourth optical lens including a seventh surface and an eighth surface; A second apex angle variable prism is formed by the prism; the second surface is a cylindrical surface having a predetermined curvature; the third surface has the same sign as the second surface; The sixth surface is a cylindrical surface having a predetermined curvature, and the seventh surface is a curvature cylindrical surface having the same sign as that of the sixth surface and approximately similar to the sixth surface. And the center axis of curvature of the second surface and the third surface is one of the first and second optical lenses. A center axis of curvature of the sixth surface and the seventh surface is a center axis of one of the third and fourth optical lenses; , Wherein the respective rotation directions are selected so as to be orthogonal to each other, and the combined focal length of the first and second apex angle variable prisms as a whole is an afocal system. 11. The first optical lens is a plano-concave cylindrical lens, the second optical lens is a convex plano-cylindrical lens, the third optical lens is a plano-concave cylindrical lens, and the fourth optical lens is a convex plano-cylindrical lens. The variable apex angle prism according to claim 10, wherein the prism is configured as a lens. 12. The variable apex angle prism according to claim 10, wherein a cylindrical lens in which a combination of concave and convex surfaces of the first to fourth cylindrical lenses is reversed. 13. The first optical lens is a plano-concave cylindrical lens, the second optical lens is a convex plano-cylindrical lens, the third optical lens is a plano-convex cylindrical lens, and the fourth optical lens is a concave plano-cylindrical lens. The variable apex angle prism according to claim 10, wherein the prism is configured as a lens. 14. The first optical lens is a plano-convex cylindrical lens, the second optical lens is a concave plano-cylindrical lens, the third optical lens is a plano-concave cylindrical lens, and the fourth optical lens is a convex plano-cylindrical lens. The variable apex angle prism according to claim 10, wherein the prism is configured as a lens. 15. The first and second apex angle variable prisms are mounted in independent lens barrels, and the second and fourth optical lenses or the first and third optical lenses are provided in respective lens barrels. 11. The top according to claim 10, wherein the center axes of curvature of the first and third optical lenses or the second and fourth optical lenses are fixed and can be independently rotated as their rotation center axes. Variable angle prism. 16. A lens rotation guide means is provided between the second surface and the third surface and between the sixth surface and the seventh surface, and the first and second optical lenses are provided with a first guide means. Or the third optical lens can be independently rotated, or the second and third optical lenses can be independently rotated with respect to the first and third optical lenses. 11. The variable apex angle prism according to claim 10, wherein: 17. The first and third optical lenses or the second optical lens.
11. The variable apex angle prism according to claim 10, wherein a driving means is provided for each of the first and fourth optical lenses, and a rotating power is applied to the corresponding optical lens by the driving means. 18. The drive means comprises a pinion connected to a drive motor and a rack meshing with the pinion and having a radius of curvature, wherein the rack is the first and third optical lenses or the first or third optical lens. 2
The variable apex angle prism according to claim 10, wherein the prism is attached to a fourth optical lens. 19. A first apex angle, comprising a first optical lens having a first surface and a second surface and a second optical lens having a third surface and a fourth surface, which are arranged close to each other. A variable apex, a third optical lens including a fifth surface and a sixth surface, and a fourth optical lens including a seventh surface and an eighth surface; A second apex angle variable prism is configured by the prism, the second surface is a cylindrical surface having a predetermined curvature, and the third surface is a second surface.
The surface has the same sign as that of the surface, and has a cylindrical surface having a curvature approximately similar to the second surface, the sixth surface has a cylindrical surface having a predetermined curvature, and the seventh surface has a sixth surface.
The surface has the same sign as that of the surface, and has a cylindrical surface of curvature approximately similar to the sixth surface, and the center axis of curvature of the second surface and the third surface is the rotation center of one of the first and second optical lenses. And the center axes of curvature of the sixth surface and the seventh surface are the third or fourth axes.
And the respective rotation directions are selected so that the respective rotation surfaces are orthogonal to each other, and the first and second apex angle variable prisms as a whole are An apex angle variable prism designed so that the combined focal length becomes an afocal system. The apex angle variable prism is attached to an optical system of a video camera as a shake correction mechanism, and an angular velocity sensor is provided in the lens barrel. And the shake of the video camera is detected, and based on the detected shake component, the first and second optical lenses for the second and fourth optical lenses or the first or second optical lens.
By controlling the rotation of one or both of the second and fourth optical lenses with respect to the third and third optical lenses, the apex angle of the apex angle variable prism is varied and the transmission optical axis thereof is changed. A shake correction device, characterized in that: 20. The apparatus according to claim 19, wherein the shake correcting mechanism is detachably attached to the optical system.
The shake correction device as described. 21. The optical system according to claim 21, wherein the first and third optical lenses are rotatable in directions orthogonal to each other.
When the and the fourth optical lens are configured to be rotatable in a direction orthogonal to each other, the first and / or the third optical lens or the second and / or the fourth based on the shake component detected by the angular velocity sensor That the optical axis of the first and / or third optical lens or the second and / or fourth optical lens is adjusted to perform shake correction. 20. The shake correction apparatus according to claim 19, wherein: 22. The camera shake correction apparatus according to claim 19, wherein a camera shake component is detected by the angular velocity sensor, and the camera shake of the video camera is corrected by the camera shake component.