JP3115124B2 - Optical axis deflection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical axis deflector for changing an optical axis of a light beam incident on an optical device such as a photographing device or an observation device.

[0002]

2. Description of the Related Art FIGS. 7 and 8 are block diagrams showing the prior art. FIG. 7 is a configuration diagram of the photographing apparatus. Reference numeral 101 denotes a vibration gyro for detecting the angular velocity of the photographing device, and outputs an angular velocity signal of 102. 103 is an integrating circuit;
2 is integrated and an angular displacement signal 104 is output. This signal indicates the angular displacement of the imaging device. Reference numeral 105 denotes a variable apex prism which is a mechanical structure of the optical axis deflector, and its apex angle can be changed by an actuator 106.

The apex angle of the variable apex angle prism is one of the apex angle sensors.
07, an apex angle signal 108 is obtained. This signal and the above-described angular displacement signal 104 are applied to an adder circuit 109 with opposite polarities, and a difference signal 110 is output. This signal is 1
The signal is amplified by an amplifier 11 and becomes 112 to obtain a drive signal 114 via a drive circuit 113 to obtain an actuator 10.
6 is driven. That is, a closed loop is formed by the configuration from 106 to 114. In this configuration, control is performed such that the difference signal of 110 is always zero, and as a result, the signal 108
Acts to coincide with the signal 104. The light beam deflected by the variable apex angle prism 105 forms an image on the CCD surface of the lens 116 by the lens group 115, and an image pickup signal 117 is obtained.

FIG. 8 shows a conventional example of an optical axis deflection device. The optical axis deflector includes a variable apex angle prism unit 120 and a driving unit 1
30 and a transmission unit 140 for transmitting the driving force.

Reference numeral 121 denotes a variable apex angle prism,
22 and 123, and the respective surfaces have a yaw axis (X-
X) and a support pin (not shown) so as to swing around a pitch axis (Y-Y).

The variable apex angle prism 121 is composed of a glass or plastic transparent plate, a frame to which the transparent plate is adhered, a bellows-like film connecting the frame, and a sealed liquid with a high refractive index. The drive unit 130 includes a permanent magnet 131, two poles magnetized in the thickness direction, and yokes 132 and 133.
And a flat coil 134 wound in a trapezoidal shape. The flat coil 134 is fixed to a coil support 141. The connecting portion 141a of the coil support 141 and the connecting portion 142 of the frame 123 of the variable apex prism are fastened by screws (not shown). Also, the coil support 1
Reference numeral 41 is supported by a support pin (not shown) so as to be swingable at a portion 141b. Although only the components for pitching (vertical direction in the screen) described above are shown and described in FIGS. 7 and 8 as the optical axis deflector described above, the shake correction system includes two systems of pitching and yawing (horizontal direction in the screen). I have.

[0007]

In the above conventional example, since the supporting point of the driving device is set in consideration of the space efficiency of the mechanical structure, the supporting point is set to the coil 134 as shown in FIG. Is the magnetic pole boundary line (J-
J) Each hypotenuse of the coil (AB,
CD) deviates from the bisector (M−M) of the line of intersection.
Therefore, there is a disadvantage that the torque transmission efficiency is poor.

It is an object of the present invention to provide an improved optical axis deflector which does not have the disadvantages of the conventional optical axis deflector.

[0009]

According to the improved optical axis deflector of the present invention, in the above-mentioned conventional optical axis deflector, the position of the coil at a position symmetrical with respect to the magnetic pole boundary line of the permanent magnet is described. By setting the support point of the coil on the bisector of the intersection line of each hypotenuse of the coil, good torque transmission efficiency is obtained.

In the improved optical axis deflector of the present invention, when the coil rotates to the maximum within the coil rotation range, the oblique side of the coil closer to the permanent magnet magnetic pole boundary line with respect to the permanent magnet magnetic pole boundary line. By setting the coil shape so as to be parallel, the space on the permanent magnet for rotating the coil is minimized, and a compact and inexpensive optical axis deflection device can be realized.

[0011]

In the optical axis deflection device of the present invention, good torque can be obtained by setting the coil support point on the bisector of the intersection of each hypotenuse of the coil at a position symmetrical with respect to the permanent magnet magnetic pole boundary of the coil. Transmission efficiency can be obtained.

Further, by setting the coil shape so that the hypotenuse of the coil closer to the permanent magnet magnetic pole boundary line is parallel to the permanent magnet magnetic pole boundary line when the coil rotates to the maximum within the rotation range of the coil. Thus, a smaller and less expensive optical axis deflector can be obtained.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with respect to a photographing apparatus equipped with the optical axis deflection device of the present invention.

A first embodiment of the present invention will be described with reference to FIGS. In the first embodiment, the optical axis deflector of the present invention is applied to a photographing apparatus having a camera shake correction function. In the optical axis deflector, the trapezoidal flat coil has a magnetic pole boundary line of a permanent magnet. The support points of the coils are set on the bisectors of the intersections of the oblique sides of the coils at the symmetrical positions in FIG.

FIG. 1 is a drawing which best illustrates the features of the present invention, and shows a driving device of an optical axis deflection device according to a first embodiment of the present invention. FIG. 2 is a configuration diagram of a photographing device equipped with the optical axis deflection device. Numeral 31 denotes a vibration gyro for detecting the angular velocity of the photographing device, and outputs an angular velocity signal of 32. An integration circuit 33 integrates the signal 32 and outputs an angular displacement signal 34. This signal indicates the angular displacement of the imaging device. 3
Reference numeral 5 denotes a variable apex prism, which is a component of a mechanical component of the optical axis deflector, the apex angle of which can be changed by an actuator 36. The apex angle of the variable apex angle prism is detected by an apex angle sensor 37, and an apex angle signal 38 is obtained.
This signal and the above-mentioned angular displacement signal 34 are added to an adder circuit 39 with opposite polarities, and a difference signal 40 is output. This signal is amplified by an amplifier 41 to become 42, and a drive signal of 44 is obtained via a drive circuit 43 to drive the actuator 36. The light beam deflected by the variable apex angle prism 35 is imaged on the CCD surface 46 by the lens group 45 and
7 image signals are obtained. FIG. 1 is a configuration diagram of the optical axis displacement device. Reference numeral 1 denotes a variable apex angle prism, which is sandwiched between frames 2 and 3 and has a support pin (not shown) so that each surface can swing around a yaw axis (XX) and a pitch axis (YY). Supported by The variable apex angle prism 1 includes a glass or plastic transparent plate and a frame body bonded to the transparent plate,
It is made up of a bellows-like film that connects the frame and a sealed liquid with a high refractive index. A permanent magnet 4 is magnetized in two poles in the thickness direction, and a yoke 5 is fixed to the permanent magnet 4 with a predetermined gap in the magnetizing direction of the permanent magnet. The yoke 6 in addition to the permanent magnet 4 and the yoke 5 constitutes a magnetic circuit of the actuator 36. Reference numeral 7 denotes a flat coil wound in a trapezoidal shape.
And the oblique sides (AB, CD) of the coil are located on the respective magnetic poles of the permanent magnet 4 in the gap formed by the permanent magnet 4 and the yoke 5. The frame 3 holding the coil support 8 and the variable apex angle prism 1 is fastened by screws (not shown) at the support 8a and the frame 3a. The coil support 8 is supported by a support pin (not shown) so as to be swingable at the support 8b. FIGS. 1 and 4 show the relationship between the support point position and the torque of the support point position.
This will be specifically described below.

The generated thrust acts in the direction perpendicular to the entire circumference of the coil, but taking into account the difference in the direction of the magnetic flux lines and the symmetry of the coil shape, C1, C2, C3, C in FIG.
4, the sum of the forces acting on the coil portions in C1 ', C2', C3 ', and C4' can be simply considered as the force acting on the entire coil. C1, C2, C3, C4, C1 ', C
The sums of the generated thrusts 2 ′, C3 ′, and C4 ′ are considered to be simplified for those acting at the positions of the respective centers of gravity. In FIG. 4, P and P ′ are C
1, C2, C3, C4, C1 ', C2', C3 ', C
This is the position of the center of gravity of 4 '. O is a point of intersection when a line perpendicular to the coil center line 1 passes through P (P '). Q is the intersection of lines passing through P (P ') and parallel to each coil side AB (CD). If the coil shape is symmetrical about the coil center line l, the coil center line l is bisected by {PQP' It becomes a line. S is the center of rotation of the coil and is the support point 8b. F ₁ and F ₂ are forces acting on P and P ′, and F ₁ γ, F
₂ epsilon is F _1, F ₂ of the SP, SP 'are vertical component,
γ and ε are angles between F ₁ and F _{2 formed} by F ₁ γ and F ₂ ε.
α is ∠PQO (∠P′QO), Δ1 and Δ2 are shift amounts between S and Q, Δ1 is a shift amount on the center line l, and Δ
Reference numeral 2 denotes a shift amount in the vertical direction from the center line l. Thrust F ₁ ,
The magnitudes of F ₂ are equal, and F ₁ = F ₂ = F. When this is used, the torque _Tc generated by the coil in FIG.
It can be expressed as an equation.

[0017]

(Equation 1)

Here, a, b, c and d are coil shape dimensions. From equation (1), it is clear that when the deviation amount Δ2 in the vertical direction of the center line 1 is Δ2 = 0, the torque T becomes maximum. Therefore, in this embodiment, since the support point 8b is set to Δ2 = 0, ∠
It is set on the bisector of PQP '(on the coil center line 1).

In the first embodiment of the present invention, the supporting point 8b is set to ΔP
By setting the values on the bisector of QP ', torque transmission efficiency can be improved.

<Second Embodiment> A second embodiment of the present invention will be described with reference to FIG. In the second embodiment, as in the first embodiment, the present invention is applied to an optical axis deflection device of a photographing apparatus having a camera shake correction function, and a trapezoidal flat coil is formed by a magnetic pole boundary line of a permanent magnet. , The support point of the coil is set at the intersection of each hypotenuse of the coil at the symmetrical position.

FIG. 5 shows a drive unit of the optical axis deflection device according to the second embodiment. In FIG. 5, those having the same reference numerals as those in FIG. 1 have the same functions. In the second embodiment, as shown in FIG. 5, the support point 8b is shown in FIG. 4, and the shift amounts Δ1 and Δ2 are Δ1 =
0, and set at positions where Δ2 = 0. As a result, loss of torque transmission efficiency due to the position of the support point S is eliminated, and transmission efficiency can be improved as compared with the conventional support point position.

<Third Embodiment> A third embodiment of the present invention will be described with reference to FIG. In the third embodiment, similar to the first and second embodiments, the present invention is applied to a driving device of an optical axis deflector having a camera shake correction function, and a trapezoidal flat coil has a permanent magnet magnetic pole boundary. Set the rotatable support point of the coil on the bisector of the intersection of each hypotenuse of the coil at a position that is symmetrical with the line, and furthermore, set the permanent The coil shape is set so that the oblique side closer to the magnet pole boundary is parallel to the permanent magnet pole boundary.

FIG. 6 shows a driving device of the optical axis deflection device according to the third embodiment. FIG. 6 (a) is a diagram of the drive coil unit where the coil is located at a position symmetrical with respect to the boundary line of the permanent magnet magnetic pole, and FIG. 6 (b) shows that the coil rotates maximally within the rotation range of the coil. It is a figure of a drive device coil part at the time of doing. 6 having the same reference numerals as those in FIG. 1 have the same functions.

The position of the support point of the coil is the same as in the first embodiment, and the amount of deviation Δ2 in the vertical direction of the center line 1 shown in FIG.
2 = 0, and is set on the bisector of ∠PQP '(on the coil center line 1). In FIG. 6, θ is the maximum rotation angle from the coil center position (the position shown in FIG. 6A).

Σ is a position where the coil is rotated by an angle θ (FIG. 6)
(Position shown in (b)), the AS connecting the point A, which is the inner circumferential angle of the coil, to the support point S is the angle formed by the permanent magnet magnetic pole boundary line m. In the third embodiment, the coil hypotenuses (AB, C
D) is angled with respect to side AS by σ at point A. Thereby, when the coil 7 rotates to the maximum (± θ) from the coil center position, the coil oblique sides (AB, CD) become parallel to the permanent magnet magnetic pole boundary line m. Thus the area S _c shown in diagonal lines in FIG. 6 becomes minimum, space for rotation of the coil 7 is also minimized and the permanent magnet areas 2H _m necessary for the coil rotation, the L _m can be minimized .

In the third embodiment, a small and inexpensive driving device which can obtain good torque efficiency by setting a rotatable coil supporting point and forming a coil shape as described above. Can be.

[0027]

As described above, in the deflection device according to the present invention, the coil support point is located on the bisector of the intersection of each of the oblique sides of the coil at a position symmetrical with respect to the permanent magnet magnetic pole boundary of the coil. , Good torque transmission efficiency can be obtained.

Also, by setting the coil shape such that when the coil rotates to the maximum within the rotation range of the coil, the oblique side of the coil closer to the permanent magnet magnetic pole boundary line is parallel to the permanent magnet magnetic pole boundary line. Thus, a smaller and less expensive optical axis deflector can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a drive unit in an optical axis deflection device according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing an outline of a mechanical structure of the optical axis deflection device.

FIG. 3 is a block diagram showing a configuration of a photographing apparatus equipped with the optical axis deflector of the first embodiment.

FIG. 4 is a diagram showing a detailed configuration of a drive unit of the optical axis deflection device according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a drive unit of an optical axis deflection device according to a second embodiment of the present invention.

FIG. 6 is a diagram showing an operation of a drive unit of an optical axis deflection device according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a photographing apparatus equipped with a conventional optical axis deflector.

FIG. 8 is an exploded perspective view of a conventional optical axis deflection device.

[Explanation of symbols]

4: permanent magnet 7: coil 8: coil support S: coil support point l: coil center line m: permanent magnet magnetic pole boundary line

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-142175 (JP, A) JP-A-4-78292 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 27/64 G03B 5/00 G03B 17/00

Claims (3)

(57) [Claims] 1. An optical axis deviating device for deviating an optical axis of a light beam incident on an optical system of an optical apparatus, wherein the optical axis deviating device has a driving device and a transmission unit for transmitting a driving force. The driving device includes a permanent magnet magnetized in two poles in a thickness direction;
A yoke member opposed to the permanent magnet with a predetermined gap in the permanent magnet magnetization direction, and a surface wound in a trapezoidal shape and arranged in the gap and perpendicular to the permanent magnet magnetization direction in the gap. A coil rotatably supported within,
An optical axis, wherein a rotatable support point of the coil is set on a bifurcation of an intersection of each hypotenuse of the coil at a position symmetrical with respect to a magnetic pole boundary line of the permanent magnet of the coil. Declination device. 2. The optical axis deflector according to claim 1, wherein a support point of the coil is set at an intersection of the respective oblique sides of the coil. 3. The oblique side of the coil, which is closer to the magnetic pole boundary of the permanent magnet, is parallel to the magnetic pole boundary of the permanent magnet when the coil rotates to the maximum within the rotation range of the coil. 2. The optical axis deflection device according to claim 1, wherein the shape of the coil is set.