JPH09230226A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a device from being projected to the outside because a variable vertex angle prism becomes larger in the case the device includes the variable vertex angle prism. SOLUTION: This device is constituted of plural lens groups 1a, 2a, 6a and 20a constituting the optical system and including the lenses for variable power and focusing, the variable vertex angle prism 7 arranged between the lens groups 1a, 2a, 6a and 20a and a variable diaphragm. In such a case, a diaphragm driving means 4 and a focusing lens group driving means 25 are arranged before and behind in an optical axis direction, and the driving means 4, the driving means 25, a 1st variable vertex angle prism driving means 10P, a variable power lens group driving means 24, and a 2nd variable vertex angle prism driving means 10Y are arranged in the phase relation of such order around an optical axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device having a variable apex angle prism and a variable diaphragm between a plurality of lens groups which are included in an optical system and include zooming and focusing.

[0002]

2. Description of the Related Art FIG. 12 is a longitudinal sectional view showing the structure of a conventional optical device including a variable apex angle prism of this type. FIG.
2, 101 is two transparent discs 101a, 101
b is connected by a flexible bellows-shaped film 101c, a transparent liquid 101e having a high refractive index is enclosed in the connection space 101d, and variable apex angle prisms 102, 103, 104, whose apex angles can be changed, Reference numeral 105 denotes a lens group forming a photographic optical system, 106 denotes an image sensor for converting an optical image formed by the photographic optical system into an electric signal, and 107 is fixed to a movable surface side 101b (rear side) of the variable apex angle prism 101. The drive coil 108 is a magnetic circuit including a magnet fixed to the fixed surface side 101a (front side) of the variable apex angle prism 101. The drive coil 107 and the magnetic circuit 108 are provided.
Thus, a driving unit that changes the apex angle of the variable apex angle prism 101 is configured.

[0003]

However, in the above-mentioned conventional example, since the variable apex angle prism 101 is arranged in front of the photographing optical system, the variable apex angle is required to pass a necessary and sufficient luminous flux to the photographing optical system. The prism becomes larger. Further, since the drive means for the variable apex angle prism is arranged outside the variable apex angle prism, there is a problem that this drive means part travels largely outside the photographing optical system.

The present invention has been made to solve the above problems, and an optical device including a variable apex angle prism has a small protruding portion to obtain a small-sized optical device having a good appearance. To aim.

[0005]

An optical device according to a first aspect of the present invention is arranged between a plurality of lens groups for zooming and focusing, which form an optical system, and between these lens groups. In the optical device having the variable apex angle prism and the variable diaphragm, the diaphragm driving means and the focusing lens group driving means are arranged in the front and rear in the optical axis direction, and the diaphragm driving means and the focusing lens are arranged around the optical axis. The group drive means, the first variable apex angle prism drive means, the variable magnification lens group drive means, and the second variable apex angle prism drive means are arranged in the order of phase relationship.

In the optical device according to the second aspect of the present invention, the diaphragm driving means and the focusing driving means are arranged in the optical axis direction at substantially the same phase angle, and the zooming driving means is the focusing driving means. Is arranged at the phase angle between the first and second variable apex angle prism driving means on the opposite side.

In the optical device according to the third aspect of the present invention, the diaphragm driving means and the focusing driving means are arranged with the phase angles shifted from each other between the first and second variable apex angle prism driving means. Is.

In the optical device according to the fourth aspect of the present invention, the first and second variable apex angle prism drive means are swing actuators.

In an optical device according to a fifth aspect of the present invention, the swing actuator has a yoke through which a magnetic flux generated by a rotor magnet and a field coil passes, and a Hall element that detects this magnetic flux as main components. It is a thing.

In the optical device according to a sixth aspect of the present invention, the first and second variable apex angle prism driving means are step motors.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 is an exploded perspective view showing an optical device according to Embodiment 1 of the present invention, in which an optical system is composed of four lens groups having convex, concave and convex shapes. A variable power operation is performed by moving the concave lens group of the second group, and a focusing operation is performed by moving the convex lens group of the fourth group. A variable aperture is provided in front of the convex lens group of the third group. A variable apex angle prism is disposed between the convex lens group of the group.

Reference numeral 1 denotes a fixed barrel for holding the first lens group 1a, 2 is a V-moving ring for holding the second lens group 2a, and 3 is the absolute position of the second lens group 2a. Is a photo-interrupter as a V reset switch for detecting a reference position for detecting the reference position, and a light-shielding member 2e provided on the V-moving ring 2 is provided to dispose infrared light and a light-receiving element. The switching position of presence / absence of 2e is electrically detected.

Reference numeral 4 denotes a known iG meter as diaphragm driving means for driving the blades 5a and 5b. The diaphragm blades 5a and 5b are moved in directions opposite to each other by the swinging motion of the rotor part, and the optical axes are centered. The aperture value is determined by changing the size of the opening. Reference numeral 6 denotes an afocal lens barrel that holds the convex lens unit 6a of the third lens group. The aperture blades 5a and 5b are sandwiched between the iG meter 4 and the afocal lens barrel 6 for positioning,
The movement of the diaphragm blades 5a and 5b is guided in the plane. 7
Is a known variable apex angle prism, made of glass, etc.
The transparent plates 7a and 7b, the flexible bellows-like film 7c for connecting the transparent plates, and the transparent liquid 7e with a high refractive index enclosed in the connecting space 7d. The apex angle of the prism formed by 7a and 7b is changed.

Reference numeral 8 denotes a V holding frame which holds the fixed side surface of the variable apex angle prism 7, 9 denotes a V movable frame which is attached to the movable side surface of the variable apex angle prism 7, and 10P denotes the apex of the variable apex angle prism 7. A swing actuator, which is a first variable apex angle prism driving means for changing the angle to vertically deviate the passing light beam, changes the apex angle of the variable apex angle prism 7Y to deviate the passing light beam in the lateral direction. This is a swing actuator which is the second variable apex angle prism driving means, and the swing actuators 10P and 10Y are respectively positioned on the V holding frame 8 and fixed by screws.

Reference numeral 20 is an R moving ring for holding the convex lens group 20a of the fourth group, and 21 is a photo interrupter as an R reset switch for detecting a reference position for determining the absolute position of the convex lens group 20a of the fourth group. , R-moving ring 20 is provided with a light-shielding member 20e provided therebetween to project and receive infrared light, and electrically detects the switching position of the presence or absence of the light-shielding member 20e.

22a and 22b are V transfer rings 2 and R
A guide rod for guiding the movement of the moving ring 20, and the V moving ring 2
Is a guide rod 22a provided parallel to the optical axis of the lens group 2a.
And a U-groove 2c that serves as a detent for the sleeve 2b that fits with the guide rod 22b that determines the optical axis position of the lens group 2a and that can move in the optical axis direction. It is supported. Similarly, the R moving ring 20 is supported by the sleeve portion 20b and the U groove portion 20c so that the lens group 20a is movable in the optical axis direction. Reference numeral 23 is a relay holder for mounting an image pickup device (not shown).

With the above construction, the four lens groups 1a, 2
The a, 6a, 20a, the variable aperture blades 5a, 5b, and the variable apex angle prism 7 are positioned by their respective supporting members and guide rods, and are arranged on substantially the same optical axis.

Reference numeral 24 is a stepping motor as a variable-magnification driving means, and the screw portion 2 is provided coaxially with the rotor.
4a is engaged with the rack portion of the rack member 2d attached to the V moving ring 2 and moves the V moving ring 2 in the optical axis direction by the rotation of the motor.

Reference numeral 25 is a step motor as a focusing driving means, which is a screw portion 2 provided coaxially with the rotor.
Rack member 20d in which 5a is attached to the R moving ring 20
, And the R moving ring 20 is moved in the optical axis direction by the rotation of the motor.

FIG. 2 is an exploded perspective view of the supporting portion and the driving portion of the variable apex angle prism 7 as seen obliquely from the left rear. The three claws 8a, 8b, 8c provided on the V support frame 8 are elastically deformed, and the three provided on the fixed surface side of the variable apex angle prism 7 are provided.
The variable apex angle prism 7 is fixed to the V support frame 8 by riding on the flange portion of the place and being caught. Similarly, the variable apex angle prism 7 is fixed to the V movable frame by the three claws 9a, 9b, 9c provided on the V movable frame 9.

FIG. 3 is an exploded perspective view in which the swing actuator is further disassembled for each component. Reference numeral 11 denotes a rotor, which is a cylindrical magnet magnetized to have two poles, and is magnetized in the arrow direction shown in FIG. 12 is a field coil, 1
3a and 13b are a magnet 11 and a field coil 1
2 is a yoke for passing the magnetic flux generated, and is formed by laminating thin ferromagnetic plate materials.

Reference numeral 14 is a Hall element for detecting the magnetic flux, and is arranged so that the detection direction of the detection section 14a is perpendicular to the magnetizing direction of the magnet 11 as shown in FIG. . Therefore, when the rotor 11 rotates, the detection direction component of the magnetic flux leaking toward the Hall element changes,
An electric output corresponding to the rotation angle can be obtained.

Reference numeral 15 is a support member for rotatably supporting the rotor 11, and pins coaxial with the rotor 11 are provided at both ends. Reference numeral 16 denotes a drive pin having a spherical shape 16a at its tip, which is press-fitted and fixed in parallel to a position eccentric to the rotation axis of the support member 15. 17 and 18 are parts 11
A case and a lid for positioning and accommodating ~ 16.
Reference numeral 19 is a leaf spring that biases the rotor 11 in the axial direction, and is fastened to the case 17 together with the lid 18 by screws.

FIG. 5 shows an example of a circuit for detecting the rotation angle of the rotor 11 by the Hall element. 14 is a Hall element, 14b is a constant current circuit section for driving the Hall element 14,
Reference numeral 14c is a differential amplifier circuit for inputting the output of the output terminal of the Hall element, and the variable resistor VR1 adjusts the offset amount of the electric output with respect to the rotation angle of the rotor 11. 1
Reference numeral 4d is an amplifier circuit, which is connected to the rotor 1 by the variable resistor VR2.
The change amount of the electric output with respect to the rotation angle of 1 is adjusted.
With this configuration, an appropriate electric output corresponding to the rotational angle position of the rotor 11 can be obtained.

Next, referring to FIG. 6, the movement of the other surface of the variable apex angle prism 7 when one surface is fixed will be described. The degree of freedom of movement of the movable surface of the variable apex prism 7 is defined by the parallel movement in the x-axis and y-axis directions orthogonal to the surface and the z-direction perpendicular to the surface.
Axial translation, and 6 degrees of freedom of pitch, yaw, and roll, which are rotational operations around each axis, are conceivable.

The movable surface is joined to the fixed surface by a bellows-like film 7c having a high elasticity in the z-axis direction, and the liquid 7e is enclosed in the inside thereof. Therefore, the parallel movement in the x-axis and y-axis directions is restricted by the surface rigidity of the bellows-like film 7c, and the parallel movement in the z-direction is caused by the incompressibility of the sealed liquid 7e and the bellows-like film 7c. Movement is restricted by tension in the in-plane direction.

Further, the degree of freedom of rotation around the z axis is also restricted by the rigidity of the surface of the bellows film 7c, so that the movable surface can be easily moved with respect to the fixed surface. The degree of freedom is defined by rotation around the x-axis (pitc
h) and rotation about the y-axis (yaw). Further, when the bellows film 7c of the variable apex angle prism 7 has a symmetrical shape in the optical axis direction, its rotation axis exists in the symmetry plane, that is, in the vicinity of the center plane. Since the degree of freedom of the movable surface is 2 as described above, it is understood that the amount and direction of the apex angle of the variable apex angle prism 7 can be determined by positioning the movable surface at two positions.

Next, with reference to FIGS. 7A, 7B and 7C, the connection and movement of the V movable frame 9 attached to the movable surface of the variable apex angle prism 7 and one swing actuator 10P will be described. FIG. 7A shows the swing actuator 1.
In a state before the 0P is attached, a U-shaped plate spring 9p is screwed to the V movable frame 9.

FIG. 7B shows the swing actuator 10.
With the P attached, the swing actuator 1
A sphere 16a swinging about an axis about the rotation axis R ₂ of the rotor 11 of 0P is sandwiched between the leaf spring 9p and the V movable frame 9, and the sphere 16a and the V movable frame 9 are bent by the deflection of the leaf spring 9p. Pressed. As shown, when the apex angle of the variable apex angle prism 7 is zero, the rotation axis R ₂ and the sphere 16a are located in the center plane of the variable apex angle prism 7. FIG. 7C is a view when the sphere 16a swings about the axis R ₂ by an angle θ, and as described above, the movable surface of the variable apex angle prism 7 is
The variable apex angle prism 7 is tilted about the axis R ₁ by an angle ψ.
Form the apex angle of. At this time, the ball 16a and the leaf spring 9p
The contact position with has moved upward by a dimension A as compared with FIG. 7 (b), the amount of deflection of the leaf spring 9p as shown in the figure has increased, and the urging force between the ball 16a and the V movable frame 9 has increased. It has increased.

The load of the variable apex angle prism 7, which is a driven body, is a spring load, and increases as the prism apex angle increases. The load on the variable apex angle prism 7 increases,
When it becomes larger than the biasing force of the leaf spring 9p, the ball 16a moves to V
Since the distance from the pressure contact surface of the movable frame 9 deviates from the linear relationship between the rotor rotation angle θ and the prism apex angle ψ, the biasing force of the leaf spring 9p is set to be larger than the maximum load of the variable apex angle prism 7. Must.

As described above, the urging force of the leaf spring 9p increases as the prism apex angle increases, which means that the urging force of the leaf spring 9p can be set smaller when the prism apex angle is near zero. Therefore, the ball 16a and the leaf spring 9p
Also, the frictional force with the V movable frame 9 can be reduced, which is advantageous in drive control.

Although FIG. 7 describes the driving of one axis, in practice, as described with reference to FIGS. 1 and 2, the variable apex angle prism 7 is moved in the pitch and yaw directions by the two driving means. And the arrangement of FIG. 7 is arranged at an angle of 90 °.

This biaxial drive will be described with reference to FIG.
In FIG. 8, the x-axis and the y-axis are the same as in FIG. p
The apex angles in the hit and yaw directions are proportional to the amount of movement of a point (coincident with the center of the sphere 16a) at a distance of γ from the center in the direction perpendicular to the paper surface. Since the x-axis and the y-axis are in the plane in which the rotation axis of the variable apex angle prism 7 exists, when only rotation around the x-axis or rotation around the y-axis occurs, the point on the rotating axis is the paper surface. Since it does not move in the vertical direction, the movement of one actuator is the other actuator (sphere 16a).
Position) is not affected.

Therefore, now, the angle ψ on the axis of the angle ε from the y-axis
Just think about the case of rotation. At this time, pitch
And the apex angles α and β in the yaw direction are α = ψ · sin ε and β = ψ · cos ε. The amounts of movement of the Y point in the pitch and yaw directions in the direction perpendicular to the paper surface are γ · sin ε · sin ψ and γ · cos ε · sin ψ, respectively.

Now, when ψ is θ << | (rad), ψ≈
Since sin ψ, γ · sin ε · sin ψ ≈ γ · ψ · sin ε = γ · α γ · cos ε · sin ψ ≈ γ · ψ · cos ε = γ · β, which is proportional to the apex angle in the pitch and yaw directions.

That is, by independently setting the amount of movement of the Y point in the direction perpendicular to the plane of the paper, it is possible to set the pitch and yaw.
It can be seen that the prism apex angle of each direction can be set. That is, the prism apex angle is arbitrarily determined by independently driving the swing actuators 10p and 10Y.

FIG. 9 shows each drive means and V reset switch,
It is the figure which looked at arrangement of an R reset switch and a guide rod from the front. Since the iG meter 4 and the stepping motor 25, which is the focusing driving means, do not interfere with each other in the optical axis direction, they are arranged at substantially the same phase angle. However, the swing actuator that is the driving means for the variable vertical angle prism 7 is used. It is also possible to dispose with a phase angle shifted between 10P and 10Y.

The guide rods 22a and 22b are arranged at positions substantially opposite to each other with the optical axis interposed therebetween in consideration of the balance of support of the V moving ring 2 and the R moving ring 20. Since the stepping motor 24, which is a driving unit for varying magnification, interferes with other driving units in the optical axis direction, it is arranged at the phase angle between the swing actuators 10P and 10Y on the side opposite to the stepping motor 25. .

FIG. 10 is a system diagram as an image stabilizing lens. Reference numeral 26 is an image sensor for converting an optical image into an electric signal, and the read electric signal a becomes a video signal b by the camera signal processing circuit 27. 28 is a microcomputer for controlling the driving of the lens.

When the power supply is inserted, the microcomputer 28 detects the positions of the R moving ring 20 and the V moving ring 2 with respect to the reset reference positions by the outputs of the focus reset circuit 29 and the zoom reset circuit 30, and the focus motor drive circuit 31 and the zoom motor. The step motor 25 and the step motor 24 are step-driven via the drive circuit 32, the switching positions of the signals of the reset switches 21 and 3 are detected, and the subsequent position control of the R moving ring 20 and the V moving ring 2 is performed. It is performed by counting the number of driving steps of the step motor from the reference position in the microcomputer.

Reference numeral 33 denotes a diaphragm drive circuit for opening and closing the diaphragm blades 5a and 5b, which extracts brightness information from the video signal b taken into the microcomputer 28 and controls the diaphragm value. 47 and 48 are pitc of the variable apex angle prism 7.
A pitch angle detection circuit and a yaw angle detection circuit that detect the angle of the lens in the drive angle directions of h and yaw. The angle is detected by integrating the output of an angular velocity sensor such as a vibration gyro. The outputs of both the circuits 47 and 48, that is, the information on the tilt angle of the lens is taken into the microcomputer 28. pitch position detection circuit 49 and y
The aw position detection circuit 50 is a circuit as shown in FIG. 5, detects the prism apex angle of the variable apex angle prism 7 in the pitch and yaw directions, and takes it in the microcomputer 28.

When the prism apex angle of the variable apex angle prism 7 changes, the traveling direction of the light flux passing therethrough changes and the image sensor 2
The position of the image formed on 6 changes. By controlling the change at this time in the direction opposite to the direction in which the image moves due to the actual tilt of the lens, it is possible to realize so-called camera shake correction in which the image being formed does not move even if the lens tilts. .

In the microcomputer 28, the lens tilt signal obtained by the pitch angle detection circuit 47 and the yaw angle detection circuit 48 and the prism apex angle signal obtained by the pitch position detection circuit 49 and the yaw position detection circuit 50 are respectively subtracted. Then, the field coils of the swing actuators 10P and 10Y are driven by the respective signals via the pitch coil drive circuit 51 and the yaw coil drive circuit 52. By this control, the subtracted signal acts so as to become smaller, and the so-called closed loop control keeps the prism apex angle to match the target angle.

However, in the first embodiment, since the variable apex angle prism 7 is arranged in the direction of the image pickup device from the variable magnification lens group, the amount of movement of the image with respect to the change in the vertical angle of the prism is variable. Of the pitch angle detection circuit 47 and ya.
With the lens tilt signal obtained by the w angle detection circuit 48, the apex angle amount of the variable apex angle prism 7 is not directly determined,
It is configured such that correction is performed based on the position information of the variable power lens group, and the movement of the image due to the tilt of the lens is canceled by the prism apex angle of the variable apex angle prism 7. Embodiment 2 FIG. FIG. 11 is a layout view of main parts according to the second embodiment of the present invention, and swing actuators 10P and 10Y which are the variable apex angle prism driving means of the first embodiment.
In this case, a step motor is used instead of the above, and the same parts as those in the first embodiment are designated by the same reference numerals and the duplicated description will be omitted.

Reference numeral 40 is a step-side step motor which is a first variable apex angle prism driving means, and a screw portion 40a is provided coaxially with the rotor. Four
Reference numeral 2 denotes a moving member having a rack that meshes with the screw portion 40a, which is supported by a guide rod 44 so as to be movable in the optical axis direction, and has a spherical shape 42a at a connecting portion for declining the variable apex angle prism 7. There is. Since the support mechanism of the variable apex angle prism 7 and the connecting portion with the drive actuator are the same as those in the first embodiment, duplicate description will be omitted.

Reference numeral 41 denotes a stepping motor which is a second variable apex angle prism driving means, and has the same construction as the pitch side and drives the variable apex angle prism 7 to the yaw side. The position of the step motors 40 and 41 is controlled by the microcomputer 28 based on a reference signal obtained by a reset switch (not shown).

The present invention is based on the first and second embodiments.
It is needless to say that the present invention is not limited to the above configuration, and may be any configuration as long as the function shown in the claims can be achieved.

[0048]

As described above, according to the present invention, a plurality of lens groups, which are included in the optical system, for zooming and for focusing, and a variable apex angle prism disposed between the lens groups. In the optical device having a variable diaphragm, the diaphragm driving means and the focusing lens group driving means are arranged in front and rear of the optical axis direction, and the diaphragm driving means, the focusing lens group driving means, and The variable apex prism driving means, the variable magnification lens group driving means, and the second variable apex angle prism driving means are arranged in the order of phase relations in this order, so that the variable apex prism is downsized and each of the driving means is driven. The effect is that the protruding portion can be minimized, and at the same time, the weight and cost of the entire optical device can be reduced.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an optical device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a variable apex angle prism portion.

FIG. 3 is an exploded perspective view of a swing actuator.

FIG. 4 is an explanatory diagram illustrating a magnetic circuit of a swing actuator.

FIG. 5 is a signal processing circuit diagram of a Hall element.

FIG. 6 is an explanatory diagram illustrating the degree of freedom of movement of the variable apex angle prism.

FIG. 7 is an explanatory diagram illustrating a driving state of a variable apex angle prism.

FIG. 8 is an explanatory view illustrating independence of two axes of a variable apex angle prism.

FIG. 9 is an explanatory view illustrating the arrangement of main parts.

FIG. 10 is a block diagram illustrating a system as an image stabilizing lens.

FIG. 11 is a layout explanatory diagram of main parts according to the second embodiment of the present invention.

FIG. 12 is a vertical cross-sectional view of a conventional optical device.

[Explanation of symbols]

4 iG Meter (Aperture Driving Means) 5 Aperture Blades (Variable Aperture) 7 Variable Vertical Angle Prism 10P Swing Actuator (First Variable Vertical Angle Prism Driving Means) 10Y Swing Actuator (Second Variable Vertical Angle Prism Driving Means) 24 Steps Motor (variable magnification driving means) 25 step motor (variable magnification driving means) 1a, 2a, 6a, 20a Lens group

Claims (6)

[Claims] 1. An optical device having a plurality of lens groups for zooming and focusing, which constitute an optical system, and a variable apex angle prism and a variable diaphragm arranged between the lens groups. And a focusing lens group driving means are arranged in the front and rear in the optical axis direction, and the diaphragm driving means, the focusing lens group driving means, the first variable apex angle prism driving means, and the variable magnification are arranged around the optical axis. An optical device in which the lens group driving means and the second variable apex angle prism driving means are arranged in a sequential phase relationship. 2. The diaphragm driving means and the focusing driving means are arranged at substantially the same phase angle in the optical axis direction, and the magnification varying driving means is located on the side opposite to the focusing driving means. 2. The optical device according to claim 1, wherein the optical device is arranged at a phase angle between the variable apex angle prism driving means. 3. The optical system according to claim 1, wherein the diaphragm driving means and the focusing driving means are arranged with a phase angle shifted between the first and second variable apex angle prism driving means. apparatus. 4. The optical device according to claim 1, wherein the first and second variable apex angle prism driving means are swing actuators. 5. The swing actuator has a yoke through which a magnetic flux generated by a magnet, which is a rotor, and a field coil pass, and a Hall element for detecting the magnetic flux, as main constituent elements. Optical device. 6. The optical device according to claim 1, wherein the first and second variable apex angle prism driving means are step motors.