JPH08136207A - Position detector - Google Patents

Abstract

PURPOSE: To perform the position detection of a member having the relatively large amount of movement in high accuracy by a simple constitution. CONSTITUTION: Magnets 8Pb and 8Yb having the S poles and the N poles are arranged in the neighboring pattern. At least one or more magnetic detecting means 9P and 9Y are fixed to members, which can be relatively moved with respect to the magnets 8Pb and 8Yb so that the detecting means are located between the magnets at the initial state, and detect the relative positions of the above described members. These parts are provided. A part without a magnetic pole, which has the size corresponding to the range for assuring the relative position detection of the magnets 8Pb and 8Yb and the above described members, is provided between the magnets 8Pb and 8Yb having the S poles and the N poles. The range of the linear changing part of the outputs of the magnetic detecting means 9P and 9Y with respect to the relative moving amount of each magnet and the member is expanded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a position detecting device for detecting the position of a magnetizing member which moves relatively by a magnetic detecting means such as a Hall element.

[0002]

2. Description of the Related Art Conventionally, magnetic detection sensors such as Hall elements have been widely used for rotation control of brushless motors in AV equipment such as VTRs, hard disk devices, floppy disk devices and other OA equipment.

FIG. 14 shows the structure of a three-phase brushless motor. FIG. 14 (a) is a sectional view and FIG. 14 (b) is a plan view.

In FIG. 14, 101 is a fixing member which also serves as a yoke, and 102a, 102b, 102c, 102d, 1
Reference numerals 02e and 102f denote driving coils fixed to the fixing member 101, and 103 denotes a bearing portion fixed to the fixing member 101. The fixing member 101 to the driving coil 103 form a stator.

Reference numeral 104 denotes a magnet (also referred to as a magnet) magnetized to have eight poles, 105 denotes a back yoke of the magnet 104, and 106 denotes a rotating shaft.
The rotor is composed of 4 to the rotating shaft 106.

Hall elements 107a, 107b and 107c are arranged on the fixed member 101. The output detects the boundary between the magnetic poles of the magnet 104, and the drive coils 102a to 102f that are sequentially excited are switched, thereby rotating the rotor. Rotates.

Further, as an example of detecting a relatively large displacement with a Hall element, there is a diaphragm device which is a light quantity control means of a consumer camcorder. The position of the magnet rotor magnetized in two poles is detected by the Hall element, and the aperture value is obtained by calculation.

Further, a plate-shaped magnet having an N-pole and an S-pole joined to a member to be detected which moves in parallel with a fixed member provided with a driving coil and a Hall element is provided. Japanese Unexamined Patent Publication No. 59-88602 discloses a device for monitoring the position of the detected member by detecting the change of the magnetic flux due to the movement of the detected member with the Hall element.

[0009]

However, in the above-mentioned conventional example, since the magnetic flux of the magnet rotor detected by the Hall element changes spatially in a non-linear manner, the Hall element with respect to the moving amount of the rotor is changed. Output is poor in linearity, and was limited to applications such as brushless motors that detect only the boundaries of magnetic poles, and applications that detect approximate positions such as aperture value detection of camcorders.

Further, according to the apparatus of Japanese Patent Laid-Open No. 59-88602, attention is paid to the fact that the magnetic flux density of the composite magnetic field near the joint of each magnet has linearity in a considerable range, and this portion is used. This enables accurate position control, but since the range of the linear change portion of the magnetic flux density by each magnet is narrow, only minute position changes can be detected, and its application is extremely limited. Was there.

(Object of the Invention) An object of the present invention is to provide a position detecting device having a simple structure and capable of accurately detecting the position of a member having a relatively large movement amount.

[0012]

In order to achieve the above-mentioned object, the present invention according to claims 1 to 5 provides an S-pole magnet and an N-pole magnet which are arranged adjacent to each other, and a magnet relative to these magnets. A position detecting device fixed to a movable member in an initial state so as to be positioned between the magnets, and at least one magnetic detecting means for detecting a relative position of the member. Between the S-pole magnet and the N-pole magnet, a non-magnetic pole portion having a size corresponding to the relative position detection guaranteed range of these magnets and the member is provided, and the magnetic detection means for the relative movement amount of each magnet and the member. The range of the linear change part of the output of is expanded.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments.

1 and 2 show a first embodiment in which the present invention is applied to an image blur correction device for an optical device such as a video camera. FIG. 1 is a sectional view of a main portion, and FIG. Shows an exploded perspective view of a movable part, respectively.

In these figures, 1 is a variable apex angle prism, which is a transparent plate 1a, 1b such as glass, supporting frames 1c, 1d for supporting the transparent plates 1a, 1b, and supporting frames 1c, 1d. A bellows-shaped film 1 connecting the reinforcing rings 1e and 1f for reinforcement and the support frames 1c and 1d.
g, and a transparent liquid with a high refractive index (not shown) filled in the formed internal space.

Reference numeral 2 is a part of a lens barrel incorporating an image blur correction device using the variable apex angle prism 1.
Reference numerals b and 3c are parts of the lens group of the optical system. 4 is a support fixed to the lens barrel 2 and 5 is a variable apex angle prism 1.
A fixed frame for fixing one surface of the variable angle prism 1 to the support 4, and a support frame 6 fixed to the other surface of the variable apex angle prism 1.

Coils 7P and 7Y (not shown in FIG. 1) are fixed to the support frame 6 at right angles by adhesion or the like. An upper yoke 8Pa, a magnet 8Pb, and a lower yoke 8Pc that is a back yoke of this magnet 8Pb are arranged with a certain gap maintained on both sides of the coil 7P to form a magnetic circuit to form an actuator 8P. (The upper yoke, the magnet, and the lower yoke are held by a space member (not shown)).

When the coil 7P is energized, a Lorentz force is generated to drive the support frame 6. An actuator 8Y (see FIG. 2) is also arranged in the coil 7Y in a similar configuration, and the combined force of the actuators 8P and 8Y acts on the support frame 6.

Reference numerals 9P and 9Y (see FIG. 2) are Hall elements, which are magnetic detection elements located in the central portions of the coils 7P and 7Y, respectively, and detect the magnetic flux in the gaps of the actuators 8P and 8Y to change the variable top. It constitutes an apex angle sensor for detecting the pitch of the angular prism 1 and the apex angle in the yaw direction.

Next, the deformation of both sides of the variable apex angle prism 1 when a combined force is applied to the variable apex angle prism 1 by the actuators 8P and 8Y in the pitch and yaw directions will be described with reference to FIG.

When one surface of the variable apex angle prism 1 is fixed and the other surface is movable, axes perpendicular to each other in the center plane of the variable apex angle prism 1 are axes X and Y as shown in the drawing. X,
When the axis orthogonal to Y is Z, the degree of freedom of movement of the movable surface is considered to be six degrees of freedom of movement in each axis direction and rotation about each axis. Here, the movable surface is a bellows-like film (see FIG.
g), and the inside is filled with liquid. Therefore, movement in the X and Y axis directions is regulated by the bellows film, and movement in the Z axis direction is regulated by the incompressibility of the sealed liquid and the tension of the bellows film.

The degree of freedom of rotation about the Z axis (roll
Since l) is also regulated by the bellows film, the degree of freedom of deformation in which the movable surface can be easily deformed with respect to the fixed surface is, after all, rotation about the X axis (pitch) and rotation about the Y axis (yaw). 2), and its rotation axis is located on the central plane of the variable apex angle prism 1 due to the symmetrical shape of the bellows film.

That is, the actuator 8 (8P and 8
When the combined force generated by Y) acts on the support frame 6, the movable surface rotates with respect to the fixed surface of the variable apex angle prism 1 in the direction in which the combined force acts to form the prism apex angle.

Next, the detection of the apex angle of the variable apex angle prism 1 by the Hall element 9 (9P, 9Y) will be described with reference to FIGS.
Will be explained.

FIG. 4 shows a magnet 8b (8Pb, 8Y).
3B is a plan view of the Hall element 9 as viewed from the gap direction of the actuator 8. The position of the Hall element 9 shown in the figure shows the initial position (the apex angle of the variable apex angle prism 1 is 0), and the variable apex angle prism 1 is shown. It moves as shown by the arrow by the rotation of the movable surface of.

FIG. 5 is a diagram showing the relationship between the vertical angle (horizontal axis) of the variable vertical angle prism 1 and the output (vertical axis) of the Hall element 9. As the vertical angle of the prism increases, the magnet 8 moves.
Hall element 9 moves toward the magnetic pole (N or S pole) of b,
Since the magnetic flux passing vertically through the Hall element 9 is saturated, the detection sensitivity of this Hall element output is lowered.

The range within the broken line in FIG. 5 is the range in which the linearity of the Hall element output with respect to the prism apex angle should be guaranteed, and is related to the range within the broken line shown in FIG. 4 (the non-magnetized portion of the magnet 8b). ing. The width is set according to the amount of movement of the Hall element 9, that is, the distance from the center of rotation and the angular range that guarantees the linearity of the Hall element output with respect to the prism apex angle.

Next, the independence of the apex angle sensors in the pitch and yaw directions will be described with reference to FIG. The X axis and the Y axis are the same as those shown in FIG. 3, and are set in the center plane of the variable apex angle prism 1.

Now, let us consider a case where the movable surface of the variable apex angle prism 1 oscillates by an angle θ from the Y axis (yaw axis) as shown in the figure. At this time, the inclinations of the movable surface in the pitch and yaw directions are α = θ · sinφ and β = θ · cosφ, respectively, and if the angles of α and β can be detected by the apex angle sensors, the apex angle sensors in the pitch and yaw directions can be detected. The independence of is completely preserved. The output of the apex angle sensor is obtained by the amount of movement of the two Hall elements in the direction perpendicular to the paper surface. Hall element 9P, 9
The movement amounts of Y are γ · sinφ · sinθ and γcosφ · sinθ, respectively. However, γ is the distance from the variable apex angle prism 1 to the Hall elements 9P and 9Y.

Now, considering an angle such that sin θ≈θ,
Γ · sin φ · θ = γ · α and γ cos φ · θ = γ · β, respectively, and the two Hall element outputs are within the minute angle range (s
in θ≈θ), each is proportional to only the pitch and the apex angle of the yaw, and the independence of the two axes of the apex angle sensor is maintained.

FIG. 7 is a block diagram showing the arrangement of an image blur correction apparatus using the variable apex angle prism 1.

Reference numeral 1 is a variable apex angle prism, and 20 is a photographing optical system in which the variable apex angle prism 1 is arranged at the forefront. Two
Reference numeral 1 denotes a vibration gyro that is an angle sensor, which is fixed to a fixing member of the device and outputs the angular velocity of the device as a signal. This angular velocity signal is output to the BPF by the signal processing circuit 22.
After being subjected to processing such as (band pass filter), it is integrated by the integrator 23 and becomes the angle signal a of the device. Reference numeral 24 denotes an apex angle sensor including the above-described Hall elements 9P and 9Y, which outputs a signal proportional to the apex angle of the variable apex angle prism 1. This signal is subjected to amplification, filtering, etc. by the signal processing circuit 25 and becomes the apex angle signal b.

The angle signal a and the apex angle signal b of the variable apex angle prism are added in opposite polarities by the adder circuit 26 to obtain a signal c. This signal c is amplified by the amplifier 27,
The actuator 2 is converted into a drive signal by the drive circuit 28.
The prism apex angle of the variable apex angle prism 1 is changed by driving 9.

In the above circuit configuration, the signal c becomes zero, that is, the angle signal a of the apparatus and the variable apex angle prism 1.
Of the apex angle sensor 2 so that the prism apex angle signals b of
A feedback circuit including the variable apex angle prism 1 from 4 to the actuator 29 is formed.

Since the variable apex angle prism 1 is driven in a direction in which the movement of the device is canceled, the state of the light beam incident on the photographing optical system 20 does not change, and image blur correction is possible.

Although FIG. 7 shows the configuration of only one axis (pitch or yaw direction), as described above,
Since the independence of the apex angle sensors in the pitch and yaw directions is maintained, the same configurations are provided in the pitch and yaw directions, respectively, and by controlling them independently, only one side of the variable apex angle prism 1 can be driven. Also, image blur correction in the yaw direction can be realized.

(Second Embodiment) FIG. 8 is a plan view showing a magnet and a Hall element according to a second embodiment of the present invention as viewed from the gap direction of the actuator.

In FIG. 8, 8b 'is a magnet and 9 is a Hall element. The position of the Hall element 9 shown in the figure shows an initial state (the apex angle of the variable apex prism is 0), and the Hall element 9 moves in the direction of the arrow by the rotation of the movable surface of the variable apex prism.

In the first embodiment, the non-magnetized region between the N pole and the S pole is a width that guarantees the linearity of the Hall element output with respect to the prism apex angle, and is set wide up to the end of the magnet 8b. However, in this embodiment, the non-magnetized region is widened only within the range in which the Hall element 9 moves, and the non-magnetized region is narrowed as much as possible in the portion that does not affect the Hall element. Therefore, the magnet 8b 'can be effectively used.

Other configurations and operations are the same as those in the first embodiment described above, and will be omitted.

(Third Embodiment) FIGS. 9 to 11 are views according to a third embodiment of the present invention. FIG. 9 is a plan view showing a magnet and a Hall element as viewed from the gap direction of the actuator. is there.

In FIG. 9, 38 is a magnet, 31a
Is a first hall element and 31b is a second hall element.

The positions of the two Hall elements 31a and 31b shown in the figure show the initial state (the apex angle of the variable apex prism is 0), and by rotating the movable surface of the variable apex angle prism, the Hall elements are moved in the direction of the arrow. The two move together. Magnet 38
The non-magnetized region between the N pole and the S pole is set narrower than that in the first embodiment, and the two Hall elements 31a and 31b are arranged so as to be positioned in the initial state at the boundary of the non-magnetized region. Therefore, the portion of the Hall element output having a good linearity with respect to the prism vertical angle of the output is switched to obtain the vertical angle output.

FIG. 10 shows a block diagram of the circuit configuration.

31a and 31b are Hall elements, 32a and 3
2b is a power supply that suppresses a constant voltage to the Hall element input, 33
a and 33b are differential amplifier circuits that differentially output Hall elements,
Reference numerals 34a and 34b are offset adjustment circuits that adjust the offset of the differentially amplified output, and reference numerals 35a and 35b are gain adjustment circuits that adjust the gain of the differentially amplified output.

The outputs of the Hall elements 31a and 31b become signals S1 and S2 in this configuration. FIG. 11 shows the signal S when the horizontal axis is the prism vertical angle of the variable vertical angle prism.
The output changes of 1 and S2 (vertical axis) are shown.

Reference numeral 36 is a comparator for comparing the signals S1 and 0. When the signal S1 is larger than 0, the switch 37 selects the signal S1 as an output, and when the signal S1 is smaller than 0, the signal S2 is selected as an output. Yes, the selected signal S1 or S2 is used as the apex angle signal S. Of course, as shown in FIG. 11, the signals S1 and S2 are offset-adjusted so that the outputs of the two Hall elements 31a and 31b at the initial positions are both 0, and the output gain with respect to the apex angle of the variable apex angle prism. The gain is adjusted so that

As described above, the non-magnetized portions of the S pole and the N pole of the magnet 38 can be narrowed by switching the portions of the plurality of Hall elements that have good linearity to output the vertical angle. Therefore, the magnet 38 can be effectively used.

The other configurations and operations are the same as those of the first embodiment.
The description is omitted because it is similar to the embodiment.

(Fourth Embodiment) FIG. 12 is an exploded perspective view of a main portion of a fourth embodiment in which the present invention is applied to an image blur correction device for optical equipment such as a video camera.

51 is a variable apex angle prism, 52P, 52Y
Is a holding member that holds the variable apex angle prism 51. The holding members 52P and 52Y have bearing hole portions 52Pa and 52Pb and 52Ya and 52Yb, respectively, and bearing pins 53Pa, 53Pb and 53Y, respectively.
It is supported by a and 53Yb so as to be swingable in the pitch and yaw directions, respectively.

54Y is a magnet, 55Y is a back yoke of the magnet 54Y, and 56Y is an upper yoke.
These 54Y, 55Y and 56Y form a closed magnetic circuit. 57Y is a drive coil fixed to the holding frame 52Y, and when the coil 57Y is energized, a drive torque is generated by Lorentz force in the closed magnetic circuit. Reference numeral 58Y is a Hall element, which detects a change in magnetic flux due to movement within a closed magnetic path, and obtains the vertical angle in the yaw direction of the variable vertical angle prism.

The drive and apex angle detection portions are shown in the yaw direction, but the drive and apex angle detection can be performed in the pitch direction with the same configuration.

Next, the apex angle detection will be further described with reference to FIG.

R is the center of swing, and corresponds to the axis YY or the axis XX in FIG. Reference numeral 54 is a magnet, 58 is a Hall element, and FIG. 13 is a plan view seen from the gap direction.

By making the position of the Hall element 58 smaller from the rotation center R, the linearity of the output of the Hall element 58 can be obtained in the required apex angle range of the variable apex angle prism.

The shake correction operation is the same as that in the first embodiment described above, and therefore its explanation is omitted.

According to each of the above-described embodiments, the movement of the movable member within the guaranteed position detection range is detected so that the linearity (accuracy) of the output of the magnetic detection means for detecting the position is sufficiently obtained. By providing the non-magnetic pole portion between the S pole and the N pole, which are arranged adjacent to the fixed member that generates the ideal magnetic flux, the position of the movable member can be accurately detected with a simple configuration, and the cost and space can be saved. There is a reduction effect.

(Correspondence between Invention and Embodiment) In this embodiment, the Hall elements 9, 31, 31b and 58 correspond to the magnetic detecting means of the present invention, and the magnet 8b (8Pb, 8Y).
b), 8b'38, 54 correspond to each magnet of the present invention.

The above is the correspondence relationship between the configurations of the embodiments and the respective configurations of the present invention, but the present invention is not limited to the configurations of these embodiments, and the functions or embodiments shown in the claims or the embodiments It goes without saying that any structure may be used as long as it can achieve the functions it has.

(Modification) In the above embodiments, the magnetic flux of the magnet of the driving means is detected by the Hall element, but a magnet dedicated to position detection may be provided separately from the driving means.

In each of the embodiments, the so-called moving coil type in which the magnetic circuit including both magnetic poles is fixed and the coil fixing member including the Hall element is movable has been described. However, the coil is fixed and the magnetic circuit is movable. It is obvious that the same configuration can be applied to the so-called moving magnet type.

Further, in the present embodiment, the magnet having a shape in which the S pole and the N pole are connected by sandwiching a portion which is not magnetized at all, is not limited to this and is not magnetized. The part may be a hole such as a polygon, a circle, an ellipse, or a shape with a gap between the S pole and the N pole.

[0064]

As described above, according to the present invention,
Between the S-pole and N-pole magnets, a non-magnetic pole portion having a size corresponding to the relative position detection guaranteed range of these magnets and members is provided,
The range of the linearly changing portion of the output of the magnetic detection means with respect to the relative movement amount of each magnet and member is widened.

Therefore, the position of a member having a relatively large amount of movement can be accurately detected with a simple structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part when a position detection device according to a first embodiment of the present invention is applied to a shake correction device of an optical device.

FIG. 2 is an exploded perspective view of a movable part of FIG.

FIG. 3 is a perspective view for explaining a degree of freedom of a movable surface of the variable apex angle prism shown in FIG.

FIG. 4 is a plan view showing a positional relationship between a magnet and a Hall element according to the first embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between the Hall element output and the prism apex angle in the first embodiment of the present invention.

FIG. 6 is a diagram for explaining the independence of the vertical angle sensors in the pitch and yaw directions in the first embodiment of the present invention.

7 is a block diagram showing the configuration of the shake correction apparatus in FIG.

FIG. 8 is a plan view showing a positional relationship between a magnet and a Hall element of a position detecting device according to a second embodiment of the present invention.

FIG. 9 is a plan view showing a positional relationship between a magnet and a Hall element of a position detecting device according to a third embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a position detection device according to a third embodiment of the present invention.

11 is a diagram showing the relationship between the signals S1 and S2 of FIG. 10 and the prism apex angle.

FIG. 12 is an exploded perspective view showing a main part when a position detection device according to a fourth embodiment of the present invention is applied to a shake correction device.

FIG. 13 is a plan view showing a positional relationship between a magnet and a Hall element of a position detecting device according to a third embodiment of the present invention.

FIG. 14 is a diagram showing a structure of a general three-phase brushless motor.

[Explanation of symbols]

 1 Variable Vertical Angle Prism 6 Support Frame 8 (8P, 8Y) Actuator 8b (8Pb, 8Yb) Magnet 8b'38, 54 Magnet 9 (9P, 9Y) Hall Element 31, 31b, 58 Hall Element

Claims (5)

[Claims] 1. An S-pole magnet and an N-pole magnet that are arranged adjacent to each other, and a member that is movable relative to these magnets, and is fixed so as to be located between the magnets in an initial state. At least one or more magnetic detection means for detecting the relative position of the member, and between the magnets of the S pole and the N pole,
A position detecting device comprising a non-magnetic pole portion having a size corresponding to a relative position detection guarantee range of the magnet and the member. 2. The non-magnetic pole portion is present only in a portion facing the magnetic detection means.
The position detection device described. 3. The position detecting device according to claim 1, wherein the non-magnetic pole portion is a non-magnetized portion that integrally connects the S-pole and N-pole magnets. 4. The position detecting device according to claim 1, wherein the non-magnetic pole portion is a gap portion provided between the S-pole magnet and the N-pole magnet. 5. The non-magnetic pole portion is a hole provided between the S-pole magnet and the N-pole magnet.
The position detection device described.