JPH0670219A - Optical axis variable device - Google Patents

Abstract

PURPOSE:To provide an optical axis variable device which needs no liquid to track a subject in a simplified structure and with the improved frequency characteristic. CONSTITUTION:This device is provided with a 1st lens 3 having a plane and a concave surface, and a 2nd lens 2 having a plane and a convex surface respectively. Then a substantially equal curvature is set between the concave and convex surfaces and these two surfaces are combined together. Then both lenses 3 and 2 are shifted relatively to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical axis variable device suitable for application to, for example, a video camera, and used for correcting image blur caused by camera shake.

[0002]

2. Description of the Related Art Various techniques have been conventionally known as a technique for correcting camera shake. Generally, camera shake is detected by a gyro sensor attached to a camera or a camera mount, and an image is corrected based on a shake signal output from this sensor.

As a method of correcting an image, a method of electrically processing an output signal from an image sensor, a method of moving the entire camera to track an object, and an optical axis variable element incorporated in an optical system of the camera are used. The method used is known.

In the conventional method using the variable optical axis element, an optical prism variable element is used in which a liquid is sealed between two glass plates to form an integral prism, and the apex angle is changed. It bends the optical axis to correct camera shake.

[0005]

The various image correction methods in the conventional camera shake correction device have their respective problems.

The method of electrically processing the output signal from the image pickup device has an advantage that there is no moving part and is excellent in reliability, but on the other hand, the entire surface of the image pickup device cannot be effectively used as video information. There is a problem that the image quality deteriorates.

The method of moving the entire camera to track an object has a drawback that the apparatus becomes large in size because the camera platform on which the camera is mounted is driven by an electric motor.

The method using the optical axis variable element incorporated in the optical system of the camera is an excellent method in which the image quality is not deteriorated and the apparatus is small. However, the optical axis variable element uses a liquid between two glasses. Since the structure is enclosed, there is a drawback that it is necessary to take measures against liquid leakage, the structure becomes complicated, and further, the frequency characteristic for changing the optical axis cannot be improved due to the damping action by the liquid.

In view of the above problems, the present invention realizes an optical axis changing device which does not require a liquid when an object is tracked by using the optical axis changing device, which is excellent in image quality and downsizing, and simplifies the structure and frequency. It aims to improve the characteristics.

[0010]

The optical axis changing device of the present invention includes, for example, a first lens 3 having a flat surface and a concave curved surface, and a second lens having a flat surface and a convex curved surface, as shown in FIG. 2 is provided, the curvatures of the concave curved surface and the convex curved surface are substantially equalized, and the concave curved surface and the convex curved surface are arranged so as to be combined, and the first lens 3 and the second lens 3 are arranged. The lens 2 and the lens 2 are moved relative to each other.

As shown in FIG. 9, for example, the optical axis changing device of the present invention has the above-mentioned blur detecting means 504 and 505 for detecting the blur of the camera and the blur detecting means 504 and 505.
The driving means 508 and 509 for driving the first lens 3 and the second lens 2 based on the detection result of 1) are provided.

[0012]

The optical axis changing device is composed of two lenses, one of which is composed of a flat surface and a concave surface, and the other of which is a lens composed of a flat surface and a convex surface.

If the concave surface and the convex surface have the same or very similar curvatures and the two are combined and the relative positions of the two are changed along the curved surface, the angle between the planes of both lenses changes, and the wedge can be changed. It acts as a mold prism and can bend the optical axis.

By attaching a driving element for changing the relative position of the both, and constructing a servo circuit from this driving element, a gyro sensor, etc. and incorporating it in the camera, camera shake correction can be realized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical axis changing device of the present invention will be described below with reference to the drawings. First, the principle of the optical axis changing device of the present invention will be described with reference to FIGS. 1, 2 and 3. Optical axis variable element 1
Is composed of a plano-concave lens 3 and a plano-convex lens 2.
The plano-concave lens 3 has a flat surface portion 3a and a concave curved surface portion 3b, and the plano-convex lens 2 has a flat surface portion 2a and a convex curved surface portion 2b. The plano-concave lens 3 and the plano-convex lens 2 are made of a glass material having the same refractive index.

The concave curved surface 3b and the convex curved surface 2b have substantially the same curvature. The plano-concave lens 3 and the plano-convex lens 2 are arranged so that the concave curved surface 3b and the convex curved surface 2b are combined. A slight gap is provided between the concave curved surface 3b and the convex curved surface 2b.

As shown in FIG. 2, when the plano-concave lens 3 and the plano-convex lens 2 are in a positional relationship such that the plane portions 3a and 2a are parallel to each other, the optical axis 4 on the plano-convex lens 2 side and the plano-concave lens 3 are arranged. The optical axis 5 on the side should be aligned.

As shown in FIG. 1, when the plano-concave lens 3 and the plano-convex lens 2 are relatively moved so that the angle formed by the plane portions 3a and 2a becomes θ, the optical axis on the plane convex lens 2 side. 4 is bent by φ with respect to the optical axis 5 on the plano-concave lens 3 side.

When the refractive index of the glass material of the plano-concave lens 3 and the plano-convex lens 2 is n, the following equation holds between θ and φ.

[Formula 1] φ = sin ⁻¹ (n × sin θ)

A graphical representation of this relationship is as shown in FIG. In FIG. 3, the horizontal axis represents θ and the vertical axis represents φ in units of angles. As is clear from the figure, in the range of θ of several degrees, it is almost proportional to φ.

An example in which the optical axis changing device of the present invention is applied to a camera shake correcting device of a video camera will be described below. In FIG. 4, reference numeral 100 denotes a camera device, which includes a camera shake correction device 500, a lens unit 200, and a camera body unit 3.
It is composed of 00.

FIG. 5 shows a schematic cross section of the camera shake correction device 500, the lens section 200, and the camera body section 300.

The camera body 300 is composed of an image pickup device 302, a signal processing circuit 303, a recording / reproducing device 304 and the like. The signal output from the image pickup device 302 is processed by the signal processing circuit 303, and the recording / reproducing device 304 uses a magnetic field. It has a function of recording on a tape and reproducing a signal recorded on a magnetic tape.

The lens section 200 includes a mount ring 301.
By the operation of, the camera body 300 is detachable.

The camera shake correction device 500 includes a lens unit 20.
It is detachably attached to the front part of 0.

The optical axis variable element comprises a plano-concave lens 3 and a plano-convex lens 2. The plano-concave lens 3 has a flat surface 3a.
And the plano-convex lens 2 has a flat surface portion 2a and a convex curved surface portion 2b.

The concave curved surface portion 3b and the convex curved surface portion 2b have substantially the same curvature. Plano-concave lens 3 and plano-convex lens 2
Are arranged so that the concave curved surface portions 3b and the convex curved surface portions 2b are combined with each other.

FIG. 6 shows a photographing situation (A), that is, a subject 60.
0 indicates a state during shooting, and a point 600a on the subject 600
Is imaged at a point 302a on the image sensor 302 through the camera shake correction device 500 and the lens unit 200.

FIG. 7 shows a photographing condition (B), that is, a case where the camera device 100 is shaken at an angle φ and the camera shake correction device is not operated. The point 600a on the subject is on the image sensor 302 from the point 302a to the point 302b.
An image is formed at the position moved to, and the image sensor 302 outputs a video signal as if the subject 600 moved.

FIG. 8 shows a photographing condition (C), that is, a condition where the camera shake correction is activated. The plano-convex lens 2 is moved along the curved surface 3b of the plano-concave lens 3, and the angle between the plane part 2a of the plano-convex lens 2 and the plane part 3a of the plano-concave lens 3 is θ.
Is set, the light passing through the plano-convex lens 2 and the plano-concave lens 3 is bent by φ, and the point 600 on the subject 600
The light emitted from a is imaged at a point 302a on the image sensor 302, and a video signal is output from the image sensor 302 as if the subject 600 is stationary.

FIG. 6 is a block diagram showing the configuration of the camera shake correction device 500. 504, 5
Reference numerals 05 are yaw and pitch sensors for detecting horizontal blur and vertical blur, respectively.

A computer 506 is connected with yaw and pitch sensors 504 and 505, and is also connected to the mode switch 501 and a terminal 513. The output of the computer 506 is input to the comparison circuit 507. The output of the comparison circuit 507 is connected to the yaw driving element 508 and the pitch driving element 509.

The plano-concave lens 3 is driven by the yaw drive element 508.
Is moved in the horizontal direction, and the plano-convex lens 2 is moved in the vertical direction by the pitch drive element 509.

The positions of the plano-concave lens 3 and the plano-convex lens 2 are
The outputs are detected by the position detection elements 511 and 510, and their outputs are input to the comparison circuit 507.

The mode switch 501 is provided to select whether or not to activate the shake correction system.

If the mode switch 501 is selected to activate the image stabilization system, the camera device 1
When 00 causes lateral blurring, the camera shake correction device 500 attached thereto also causes lateral blurring, and the yaw sensor 504 incorporated therein detects the blurring, and the output is input to the computer 506 and accordingly output from the computer 506. The corrected amount is input to the comparison circuit 507.

Since the comparison circuit 507 inputs the difference between the level of the signal from the position detecting element 511 attached to the plano-concave lens 3 and the correction amount output from the computer 506 to the yaw drive element 508, the plano-concave lens 3 moves to a position where blurring is corrected.

When the camera device 100 has a vertical blur, it is corrected by the plano-convex lens 2, and when it has an oblique blur, it is corrected by both the plano-convex and plano-concave lenses 2.

Reference numeral 512 denotes a power supply for operating the camera shake correction device 500. Since the power supply built in the camera body part 300 is not used, the camera body part 300 is not burdened and the camera shake correction device 500 is detached. It can be handled as a free attachment.

As described above, according to this embodiment, the optical axis changing device is composed of two lenses made of the same glass material, one of which is composed of a flat surface and a concave surface, and the other of which is composed of a flat surface and a convex surface. Lens.

If the concave surface and the convex surface have the same or very similar curvatures and the two are combined and the relative positions of the two are changed along the curved surface, the angle between the planes of both lenses changes, and the angle of the optical axis changes. Acts as a wedge-shaped prism that can be changed.

By combining such an optical axis changing device with a sensor to form a control system and attaching it to the front part of the lens portion of the camera device, camera shake can be corrected.

Since the camera shake correction device of this embodiment is configured in this way, it is a method of correcting camera shake by tilting the optical axis, and there is no deterioration in image quality due to correction.
It has a simple structure and a compact device, unlike the conventional method, it is a method that does not enclose liquid, has the advantageous characteristics that there is no attenuation effect by the liquid and the frequency characteristic of changing the optical axis angle can be improved. There is.

In this example, the camera shake correction device is detachably attached to the front part of the lens unit 200, but it goes without saying that a structure integrally incorporated in the camera device 100 may be adopted.

In the above-described embodiment, the camera shake correction control system is independent of the camera body, but it can be associated with the camera body, thereby realizing a higher degree of camera shake correction control. be able to.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0047]

According to the present invention, since the optical axis changing device for optically performing camera shake is composed of two lenses, the following effects can be obtained. (1) It is a method of correcting camera shake by tilting the optical axis, and there is no deterioration in image quality due to correction. (2) Since the optical axis changing device is composed of two lenses, the structure is simple and the device is small. (3) Unlike the conventional method, it is a method in which liquid is not enclosed, there is no damping effect by the liquid, and the frequency characteristics for changing the optical axis angle can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing the principle of an optical axis changing device of the present invention.

FIG. 2 is a cross-sectional view showing the principle of the optical axis changing device of the present invention.

FIG. 3 is a graph showing the relationship between θ and φ.

FIG. 4 is a diagram showing an embodiment of a camera shake correction device to which the present invention is applied.

FIG. 5 is a schematic cross-sectional view of an embodiment of a camera shake correction device to which the present invention has been applied.

FIG. 6 is a diagram showing a shooting situation (A).

FIG. 7 is a diagram showing a shooting situation (B).

FIG. 8 is a diagram showing a shooting situation (C).

FIG. 9 is a diagram showing a control system of a camera shake correction device to which the present invention is applied.

[Explanation of symbols]

 2 Plano-convex lens 3 Plano-concave lens 100 Camera device 200 Lens unit 300 Camera body unit 302 Imaging device 303 Signal processing circuit 304 Recording / reproducing device 500 Camera shake correction device 501 Mode switch 504 Yaw sensor 505 Pitch sensor 506 Computer 508 Yaw driving device 509 Pitch driving device 600 subjects

Claims (3)

[Claims] 1. A first lens having a flat surface and a concave curved surface and a second lens having a flat surface and a convex curved surface are provided, and the curvatures of the concave curved surface and the convex curved surface are substantially set. And are arranged so that the concave curved surface and the convex curved surface are combined with each other, and the first lens and the second lens are relatively moved. Optical axis variable device. 2. The optical axis changing device according to claim 1,
Blur detection means for detecting blurring of the camera, and the first lens and the second lens based on the detection result of the blur detection means.
2. An optical axis changing device, comprising: a driving unit that drives the lens. 3. The optical axis changing device according to claim 2,
The optical axis changing device, wherein the blur detecting means comprises a yaw sensor and a pitching sensor.