JPH09171204A - Optical axis changing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical axis changing device effectively performing the camera shake correction of an image pickup device. SOLUTION: In this device, a plane-concave lens 1 being a 1st optical element and a plane-convex lens 2 being a 2nd optical element are opposed in a state where their curved surfaces are somewhat separated, and at least either of the lenses 1 and 2 is turned. The device is provided with a turning mechanism constituted of a rotary actuator 11 having the same turning radius as the curvature of the curved surface of the lens and a shaft 12. Then, a transparent sealing member 3 whose refractive index is nearly equal to that of two lenses 1 and 2 is sealed by a seat 4 preventing leakage between the lenses 1 and 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical axis converter, and more particularly to an optical axis converter using a variable apex angle prism used for camera shake correction and the like.

[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. Particularly in an image pickup apparatus having an image pickup optical system having a zoom function, the influence of camera shake is great, and various means for correcting this have been proposed so far.

Among them, there is a method of displacing or deforming an optical element composed of an optical member to change incident light into a free angle on the emission side and emit the light. This is a method for obtaining the above effect by preventing the deterioration of the quality of incident light as much as possible, and there is a method using a variable apex angle prism. This variable apex angle prism is a prism formed by combining optical members, and the apex angle of the prism is changed by displacing one or a plurality of optical members used in the configuration.

Next, a method using a variable apex angle prism, which is a conventional camera shake correcting means, will be described.
This will be described with reference to FIGS. 7 to 11. FIG. 7 is a diagram for explaining optical axis conversion by the variable apex angle prism. FIG. 8 is a configuration example of a conventional variable apex angle prism, and FIG. 9 is a sectional view showing an operating state of the variable apex angle prism.
The same figure (a) shows the case where the light input / output surfaces of the variable apex angle prism are parallel, and the figure (b) shows the case where the light input / output surfaces have an apex angle. FIG. 10 shows a configuration example of a conventional variable apex angle prism composed of a plano-concave lens and a plano-convex lens. FIG. 10 (a) is a sectional side view thereof, and FIG. 10 (b) is a sectional side view showing an operating state. FIG. 11 is a perspective view of a mechanism for driving the variable apex angle prism.

First, the principle of optical axis conversion by the variable apex angle prism will be described with reference to FIG. Letting the apex angle of the prism 36 be α, the deflection angle of the exit be θ, and the refractive index of the prism 36 be n, with respect to the optical axis of the light L1 vertically incident on one plane sandwiching the apex angle of the prism 36, When the emission angle θ of the light L2 emitted from the plane is calculated, nsin α = sin (α + θ) (1) Since α + θ is small, nα = α + θ (2), and thus the emission angle θ is θ = (n-1) α ( 3) is represented.

Therefore, the light perpendicularly incident on one plane sandwiching the apex angle into the prism having the apex angle α and the refractive index n is angle θ = (n to the optical axis of the incident light from the other plane. -1) It will be emitted with α. For example, n = 1.5,
When α is displaced by ± 2 degrees, the deflection angle θ can be changed by ± 1 degree. By applying this principle, a variable apex angle prism has been conventionally proposed as described below.

The first structure of the conventional example is shown in FIG. This is an arbitrary distance on the optical axis L, and two plate glasses 3 facing each other are provided.
0a and 30b are arranged, and the outer peripheries of the two plate glasses 30a and 30b are connected by a bellows sealing member 32 having an expandable and contractible bellows shape to form a sealed space inside. The sealed space is filled with a transparent liquid to form an optical element, that is, a prism,
The apex angle of the prism is changed by rotating the plate glass about an axis 12 provided on at least one of the two plate glasses 30a and 30b. An optical element having this configuration is generally a VAP (Variable Angular).
r Prism) element. In addition, plate glass 30
The a and 30b and the bellows sealing member 32 are fixed by covers 31a and 31b to ensure the hermeticity.

The operation of the VAP element described above is shown in FIG. 9. In FIG. 9A, the incident light travels straight along the incident optical axis L and is emitted as it is when the plate glasses 30a and 30b are parallel to each other. 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. Light L1 incident vertically on the plate glass 30b
When the light is emitted from the plate glass 30a, the light L2 is inclined by θ = (n-1) α with respect to the incident optical axis, and the optical axis is converted.

However, in the above-mentioned VAP element, the bellows sealing member 32 is deformed by the mass of the liquid, it is difficult to keep the plate glass in the initial posture, and the liquid is moved in order to change it into a wedge shape. Therefore, there is a problem that a large driving force is required, the responsiveness is poor, and the volume changes with the temperature change of the environment, and the viscous resistance also changes, and thus the control characteristics change.

The second structure of the conventional example is shown in FIG. In this configuration, the plano-concave lens 1 and the plano-convex lens 2 are configured as optical members, and a slight gap 35 is provided between the concave surface of the plano-concave lens 1 and the convex surface of the plano-convex lens 2 which have substantially the same curvature, and they are arranged to face each other. The plano-convex lens 2 is held by an arm 10 which rotates about a shaft 12 in a direction indicated by an arrow R, and is rotated by a driving force of a rotary actuator 11.
The turning radius is made to coincide with the curvature of the convex surface of the plano-convex lens 2. The plano-concave lens 1 may be rotated, and the radius of rotation in this case is matched with the curvature of the concave surface of the plano-concave lens 1.

FIG. 10B shows the case where the plano-convex lens 2 is rotated in the clockwise direction of the arrow R about the axis 12 and an angle α is generated between the planes of the plano-concave lens 1 and the plano-convex lens 2. At this time, the light L1 incident perpendicularly to the plane of the plano-concave lens 1 is V
Similarly to the AP element, when the light is emitted from the plane of the plano-convex lens 2, the light L2 inclined by θ = (n−1) α degrees with respect to the incident optical axis.
And the optical axis will be changed.

FIG. 11 is a perspective view of the second conventional example, and the virtual center P is the rotation center of the plano-convex lens 2. Plano-convex lens 2 is 2
It is held from both sides by one arm 10 and rotates about a shaft 12.

In the variable apex angle prism using the above-mentioned lens, in order to avoid contact between the plano-concave lens 1 and the plano-convex lens 2 facing each other in consideration of manufacturing precision, mechanical construction precision, and the like. Since a gap has to be provided, this causes problems such as an increase in third-order aberrations and the occurrence of ghost due to reflection at the boundary surface.

[0014]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is that the bellows sealing member of the VAP element is deformed by the mass of the liquid, and it is difficult to keep the plate glass in the initial posture. Since the liquid must be moved in order to change it, a large driving force is required, the response is poor, and the volume changes with the temperature change of the environment, and its viscous resistance also changes, and the control characteristics change, etc. And the third-order aberration due to the gap between the surfaces of the plano-concave lens and plano-convex lens facing each other in order to avoid contact between the two lenses in consideration of manufacturing accuracy and mechanical configuration accuracy. It is an object of the present invention to provide a variable apex angle prism which solves the problems such as increase in the number of rays and generation of reflection ghost on the boundary surface, and to provide an optical axis conversion device using the prism.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, in which a plano-concave lens which is a first optical element and a plano-convex lens which is a second optical element are respectively provided with curved surfaces. A rotary mechanism having the same radius of curvature as the curvature of the curved surface of the lens for rotating at least one of the plano-concave lens and the plano-convex lens is provided, and the plano-concave lens and the plano-convex lens are separated. An encapsulating member, which is transparent and has a refractive index substantially equal to the refractive index of the two lenses,
The optical axis conversion device is configured by enclosing with an encapsulation means that prevents leakage.

The curvature of the concave surface of the plano-concave lens is not larger than the curvature of the convex surface of the plano-convex lens by 0.5 mm or more.

The rotating shaft of the rotating mechanism for rotating at least one of the plano-concave lens and the plano-convex lens has a spherical shaft structure or a cylindrical shaft structure.

The plano-concave cylindrical lens which is the first optical element and the plano-convex cylindrical lens which is the second optical element are made to face each other with their respective curved surfaces slightly separated, and the plano-concave cylindrical lens and the plano-convex cylindrical lens are opposed to each other. A rotation mechanism that rotates the lens and has the same rotation radius as the curvature of the curved surface of the lens is provided, and is transparent between the plano-concave cylindrical lens and the plano-convex cylindrical lens,
An optical axis conversion device is configured by enclosing an encapsulating member having a refractive index substantially equal to that of the two lenses by encapsulating means for preventing leakage.

The curvature of the concave surface of the plano-concave cylindrical lens is not larger than the curvature of the convex surface of the plano-convex cylindrical lens by 0.5 mm or more.

The rotating shaft of the rotating mechanism for rotating the plano-concave cylindrical lens and the plano-convex cylindrical lens is
It has a cylindrical shaft structure.

The plano-concave lens, which is the first optical element, and the plano-convex lens, which is the second optical element, have their respective curved surfaces opposed to each other, and a lubricating member is sandwiched between them so as to be slidable by an elastic member. Then, the optical axis conversion device is provided with a driving mechanism that presses the plano-convex lens and slides the plano-convex lens along the concave surface of the plano-concave lens.

A plano-concave cylindrical lens which is the first optical element and a plano-convex cylindrical lens which is the second optical element can be slid by an elastic member with their respective curved surfaces facing each other and a lubricating member interposed therebetween. The optical axis conversion device is provided with a driving mechanism that holds the flat state and presses the plano-convex cylindrical lens along the concave surface of the plano-concave cylindrical lens.

The above-mentioned problems are solved by constructing an optical axis conversion device characterized in that the lubricating member is colored and the lubricating member is sealed by a sealing means.

As described above, since the encapsulating member or the lubricating member having a refractive index close to that of the lens is inserted into the gap provided between the opposing surfaces of the plano-concave lens and the plano-convex lens, the third-order aberration is increased and the boundary surface is increased. It prevents the occurrence of reflection ghosts in the.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a sectional side view showing the configuration of an embodiment of a first optical axis converter according to the present invention, and FIG. 2 is a top view of the first optical axis converter.
FIG. 3 is a sectional side view showing an operating state of the first optical axis converter. 4 is a partially broken perspective view showing the structure of the first optical axis converter, and FIG. 5 is a sectional view showing the structure using the first optical axis converter as an imaging device. . FIG. 6 is a sectional side view showing a configuration and an operating state of an embodiment of a second optical axis converter according to the present invention.

The first embodiment of the optical axis converter is shown in FIG.
As shown in, the plano-concave lens 1 and the plano-convex lens 2 are arranged so that their curved surfaces are slightly separated and face each other. The plano-convex lens 2 is rotatably supported by a shaft 12 via an arm 10 so as to rotate with a radius of curvature substantially matching the curvature of the convex surface, and is rotated by a rotary actuator 11 in a direction indicated by an arrow R. Be moved. The shaft 12 may have a spherical support structure or a concentric support structure.

The curvature of the concave surface of the plano-concave lens 1 is the plano-convex lens 2.
The radius of curvature of the convex surface of is not more than 0.5 mm, and the concave surface of the plano-concave lens 1 and the convex surface of the plano-convex lens 2 are set to be concentric (or concentric spherical), and enclosed between both curved surfaces. The member 3 is sealed with a seal 4 for preventing leakage. The encapsulating member 3 preferably has the same refractive index as that of the lens. When the lens material is BK7, the refractive index n is 1.5163, and when the lens material is PMMA, the refractive index n is 1.490. Therefore, it is assumed that the seed oil has a refractive index close to these values (n = 1.
516), benzene (n = 1.5012), paraffin oil (n = 1.48) and rose oil (n = 1.4).
9) etc. can be used as the suitable sealing member 3.

It is necessary to control the rotation of the plano-convex lens 2 in a normal posture, that is, a state in which the planes of the plano-concave lens 1 and the plano-convex lens 2 are parallel to each other, and this posture is provided on the fixed side. The tilt of the plano-convex lens 2 is detected by the light-emitting element 5, the light-receiving element 6, and the mirror 7 fixed to one end of the plano-convex lens 2. That is, the light emitted from the light emitting element 5 is reflected by the mirror 7 and received by the light receiving element 6. On the light receiving element 6, the light reaches a position corresponding to the inclination of the mirror 7, so that by using the light receiving element 6 as a CCD linear sensor, for example, a signal corresponding to the reaching position can be obtained. This signal is compared with the correct position by the control circuit 40, and based on the result, the rotary actuator 11 is rotated via the drive circuit 41, and the plano-convex lens 2 is maintained in the normal posture.

FIG. 2 is a top view of the above-mentioned optical axis converter, in which the arm 10, the rotary actuator 11 and the shaft 12 are arranged so as not to interfere with the optical axis L.

The operation of this optical axis converter will be described with reference to FIG. 3. According to the shake signal from the X-axis shake sensor 23 or the Y-axis shake sensor 24 on the fixed side,
A control amount is calculated by the control circuit 40, and the rotary actuator 11 is rotated by the drive circuit 41 to generate an angle α between the planes of the plano-convex lens 2 and the plano-concave lens 1. As a result, the light L1 incident perpendicularly on the plane of the plano-concave lens 1
Means that the optical axis is displaced by the angle θ calculated by the equation (3) and the light L2 is emitted from the plane of the plano-convex lens 2.
At this time, the hand-shake preventing control of the plano-convex lens 2 is performed over the normal posture control.

Further, in the above-mentioned optical axis converting apparatus, the weight of the plano-convex lens 2 always causes a load of the rotational moment to be applied to the rotary actuator 11, and in order to remove this load, the plano-convex lens 2 is loaded via the shaft 12. It is effective to add a member for canceling this rotational moment to the opposite side.

A specific structure of the above-mentioned optical axis converter will be described with reference to FIG. The plano-concave lens 1 and the plano-convex lens 2 are held via a seal 4 so as to be movable relative to each other. Although not shown in FIG. 4, an encapsulating member is filled inside the seal 4. The plano-concave lens 1 is supported by a Y-axis arm 10y, is connected to a Y-axis motor 11y via a Y-axis 12y, and has an arrow R in the Y-axis direction.
It is rotated in the direction indicated by y. On the other hand, the plano-convex lens 2 is supported by the X-axis arm 10x, is connected to the X-axis motor 11x via the X-axis 12x, and is rotated in the direction indicated by the arrow Rx in the X-axis direction. Since the Y-axis motor 11y and the X-axis motor 11x are fixed to the housing 20, the plano-concave lens 1
The plano-convex lens 2 rotates with respect to the housing 20, that is, with respect to the image pickup element 22 fixed to the housing 20, about a virtual center P having a radius of gyration that matches the curvature of the lens. Reference numeral 21 denotes an image pickup optical system, which is a lens system for forming an image on the image pickup element 22.

FIG. 5 shows an example in which the optical axis converter of the present embodiment is used in the image pickup apparatus 100. The X-axis camera shake sensor 23 and the Y-axis camera shake sensor 24 fixed to the housing 20.
The camera shake detection signal is input to a signal processing circuit 42 including a CPU, a camera shake correction signal is generated, and is input to an X-axis motor drive circuit 43x and a Y-axis motor drive circuit 43y. Motor 11x and Y-axis motor 1
In addition to 1y, the plano-concave lens 1 and the plano-convex lens 2 are rotated to convert the incident optical axis to correct camera shake.

The rotating mechanism is not limited to the one described above, and for example, one of the plano-concave lens 1 and the plano-convex lens 2 is fixed and the other one is rotated about both the X axis and the Y axis. May be. At this time, the bearing may have a gimbal structure or a spherical bearing structure.

FIG. 6 is a diagram showing the configuration and operating state of the second embodiment of the optical axis converter according to the present invention, which differs from the first embodiment in the configuration of the lens holding and control mechanism. It is a thing.

In the second embodiment, the plano-concave lens 1 and the plano-convex lens 2 are opposed to each other, a lubricating member 25 is sandwiched therebetween, and the plano-convex lens 2 is slid along the concave surface of the plano-concave lens 1. It is configured to have a device. The plano-convex lens 2 is pressed against the plano-concave lens 1 by a spring 8, and a lubricating member 25 is sandwiched between them, and a seal 4 prevents the lubricating member 25 from leaking. In addition, the plano-convex lens 2
A linear actuator 9 composed of a cylinder 9a for driving the plano-convex lens 2 and a rod 9b is provided at one end of the cylinder 9a, and the cylinder 9a is extended from the rod 9b.
Alternatively, the plano-convex lens 2 is pulled in and slides along the concave surface of the plano-concave lens 1.

The normal attitude control of the plano-convex lens 2 and the camera shake correction control method are the same as those of the first embodiment of the optical axis converter, and the description thereof is omitted here.

The above variable apex angle prism may be constructed by using a plano-concave cylindrical lens and a plano-convex cylindrical lens instead of the plano-concave lens 1 and the plano-convex lens 2. According to this configuration, two sets of plano-concave cylindrical lens and plano-convex cylindrical lens corresponding to each axial direction are used to convert the optical axis into two axial directions orthogonal to each other in a plane perpendicular to the optical axis. Need to be configured. Other configurations and operations are the same as those described above.

[0039]

According to the variable apex prism of the present invention, the volume of the liquid enclosed between the lenses is made sufficiently small, so that the expansion of the lens and the liquid is less likely to be affected when the environmental temperature changes, and Since the lens can be rotated without changing the liquid shape, the optical axis conversion speed is increased. Furthermore, by using this variable apex angle prism, it is possible to realize a high-performance image stabilization apparatus that does not generate ghosts.

[Brief description of the drawings]

FIG. 1 is a sectional side view showing a configuration of an embodiment of a first optical axis converter according to the present invention.

FIG. 2 is a top view of the first embodiment example.

FIG. 3 is a sectional side view showing an operation state of the first embodiment example.

FIG. 4 is a partially cutaway perspective view of the first embodiment.

FIG. 5 is a cross-sectional view showing a configuration in which an image pickup apparatus according to the first embodiment is used.

FIG. 6 is a sectional side view showing a configuration and an operating state of an embodiment of a second optical axis converter according to the present invention.

FIG. 7 is a diagram for explaining optical axis conversion by a variable apex angle prism.

FIG. 8 is a configuration example of a conventional variable apex angle prism.

9A and 9B are cross-sectional views showing an operating state of the conventional variable apex angle prism shown in FIG. 8, in which FIG. This is the case where there is a vertical angle between the input and output surfaces.

FIG. 10 is a structural example of a conventional variable apex angle prism composed of a plano-concave lens and a plano-convex lens, in which (a) is a sectional side view and (b) is a sectional side view showing an operating state. .

11 is a perspective view showing a driving mechanism of the variable apex angle prism shown in FIG.

[Explanation of symbols]

 1 Plano-Concave Lens 2 Plano-Convex Lens 3 Encapsulation Member 4 Seal 5 Light-Emitting Element 6 Light-Receiving Element 7 Mirror 8 Spring 9 Linear Actuator 9a Cylinder 9b Rod 10 Arm 10x X-axis Arm 10y Y-axis Arm 11 Rotation Actuator 11x X-axis Motor 11y Y-axis Motor 12 Axis 12x X axis 12y Y axis 20 Housing 21 Imaging optical system 22 Imaging device 23 X axis camera shake sensor 24 Y axis camera shake sensor 25 Lubricating members 30a, 30b Plate glass 31a, 31b Cover 32 Bellows sealing member 33 Liquid 35 Gap 36 Prism 40 Control Circuit 41 Drive circuit 42 Signal processing circuit 43x X-axis motor drive circuit 43y Y-axis motor drive circuit

Claims (13)

[Claims] 1. A plano-concave lens, which is a first optical element, and a plano-convex lens, which is a second optical element, are opposed to each other with their respective curved surfaces slightly separated, and at least one of the plano-concave lens and the plano-convex lens is rotated. A rotating mechanism having a rotating radius that is the same as the curvature of the curved surface of the lens that moves is provided, and the encapsulation that is transparent between the plano-concave lens and the plano-convex lens and has a refractive index substantially equal to the refractive indexes of the two lenses. An optical axis converting device, characterized in that the member is sealed by a sealing means for preventing leakage. 2. The optical axis conversion device according to claim 1, wherein the concave surface curvature of the plano-concave lens is not larger than the convex surface curvature of the plano-convex lens by 0.5 mm or more. 3. The light according to claim 1, wherein a rotation shaft of a rotation mechanism that rotates at least one of the plano-concave lens and the plano-convex lens has a spherical shaft structure. Axis conversion device. 4. The optical axis conversion device according to claim 1, wherein the rotation shaft of the rotation mechanism that rotates the plano-concave lens and the plano-convex lens has a cylindrical shaft structure. . 5. A plano-concave cylindrical lens which is the first optical element and a plano-convex cylindrical lens which is the second optical element are opposed to each other with their respective curved surfaces slightly separated.
A rotation mechanism that rotates the plano-concave cylindrical lens and the plano-convex cylindrical lens and has the same radius of curvature as the curvature of the curved surface of the lens is provided, and the plano-concave cylindrical lens and the plano-convex cylindrical lens are transparent. The optical axis conversion device is characterized in that an encapsulating member having a refractive index substantially equal to that of the two lenses is encapsulated by encapsulating means for preventing leakage. 6. The optical axis conversion device according to claim 5, wherein the curvature of the concave surface of the plano-concave cylindrical lens is not larger than the curvature of the convex surface of the plano-convex cylindrical lens by 0.5 mm or more. 7. The rotating shaft of a rotating mechanism for rotating the plano-concave cylindrical lens and the plano-convex cylindrical lens has a cylindrical shaft structure. Optical axis converter. 8. A state in which a plano-concave lens, which is a first optical element, and a plano-convex lens, which is a second optical element, have curved surfaces opposed to each other, and a lubricating member is sandwiched therebetween, and can be slid by an elastic member. And an optical axis conversion device, further comprising: a drive mechanism that presses the plano-convex lens and slides the plano-convex lens along the concave surface of the plano-concave lens. 9. A plano-concave cylindrical lens, which is the first optical element, and a plano-convex cylindrical lens, which is the second optical element, are made to slide by an elastic member with their respective curved surfaces facing each other and a lubricating member interposed therebetween. The optical axis conversion device is provided with a drive mechanism for holding the state in which the plano-convex cylindrical lens can be pressed, and sliding the plano-convex cylindrical lens along the concave surface of the plano-concave cylindrical lens. 10. The optical axis conversion device according to claim 8, wherein the lubricating member is colored. 11. The optical axis conversion device according to claim 9, wherein the lubricating member is colored. 12. The optical axis conversion device according to claim 8, wherein the lubricating member is sealed by a sealing means. 13. The optical axis conversion device according to claim 9, wherein the lubricating member is sealed by a sealing means.