JPH05340711A - Positional information generator, electromagnetic driving device, and shutter driving device - Google Patents

Abstract

PURPOSE:To generate position signals at a shorter pitch. CONSTITUTION:A first and second yokes 205 and 206 are arranged in such a way that the front ends of their combs are faced to each other and the front end sections of the comb of the first yoke 205 are magnetized in the same magnetic pole, with the front end sections of the comb of the second yoke 206 being magnetized in the other magnetic pole, so that the magnetic fluxes generated from the front end sections of the comb of one yoke to the front end sections of the comb of the other yoke can be alternately inverted at every pitch of the combs.

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 information generator for generating position information by a magnetic signal, an electromagnetic drive device having a movable iron piece and a coil, and a shutter drive device.

[0002]

2. Description of the Related Art Conventionally, as is known in encoders, the amount of movement of a medium on which position information is magnetically recorded is detected by counting pulse signals in a non-contact manner with a Hall element or MR element. The device is known.

FIG. 21 shows a schematic configuration of this type of device.

In FIG. 21, reference numeral 300 denotes a rotor made of a permanent magnet, in which different magnetic poles are alternately formed on the circumference at equal intervals t and the magnetizing direction is the radial direction, which corresponds to the above-mentioned recording medium. .. Reference numeral 301 denotes a magnetic detecting means such as a Hall element or an MR element for detecting a change in magnetic pole when the rotor 300 rotates in the direction of arrow A or vice versa. By counting the number of times, the rotation amount of the rotor 300 can be calculated.

[0005]

However, in the above-mentioned conventional example, in order to make the detection pitch of the rotation angle of the rotor 300 fine, the pitch of the magnetic poles must be made fine. If the pitch of the magnetic poles is made too small (for example, the uniform interval t in FIG. 21 is about "0.1 mm"), the pitch may vary due to the accuracy of the magnetizing tool. There is a problem that it becomes difficult to magnetize the magnetic flux density so that it can be detected.

FIG. 22 is a diagram showing another device of this type.

In FIG. 22, reference numeral 302 denotes a rotatable gear wheel made of a magnetic material. 303 is a permanent magnet,
The 303a side is magnetized as an N pole and the 303b side is magnetized as an S pole. Reference numeral 304 denotes a first yoke made of a magnetic material, one end surface 304b of which faces the permanent magnet 303 and the other end surface 304a of which faces the gear 302. 305 denotes one end surface 30.
Reference numeral 5b is a second yoke made of a magnetic material, which is opposed to the permanent magnet 303 and has the other end surface 305a opposed to the gear 302 with the magnetic detection means 301 interposed therebetween. The distance between the crest portion 302a of the gear and the end surface 305a is c.

The magnetic detecting means 301 is arranged between the gear 302 and the end surface 305a of the second yoke 305, and
The change in the passing magnetic flux is detected when the crests 302a and the troughs 302b of the gear alternately come to the positions facing the magnetic detection means 301 by the rotation of 2. It is possible to detect the rotation amount of the gear 302 by counting the number of times the magnetic flux changes.

However, even in this structure, when the detection pitch is small, that is, when the distance a between the crest 302a and the trough 302b is small, the height of the crest 302a, that is, the dimension, due to manufacturing problems of the gear 302. b will also be small. Therefore, the gear 302 and the second
The gap between the end surface 305a of the yoke 305 changes from the distance “b + c” to the distance c, and the dimension b is sufficiently smaller than the distance c, so that the change in the magnetic flux is small, and the magnetic detecting means 301 Has a problem that it becomes difficult to detect.

That is, it is difficult for any of the devices to generate a position signal with a finer pitch, and it has not been possible to improve the detection accuracy of the rotation amount.

Next, another problem will be described.

By an electromagnet having a coil and a movable iron piece,
As a method of driving the lever or the like, for example, a configuration as shown in FIG. 23 can be considered.

In FIG. 23, 101 is a movable iron piece and 10
2 is a coil and 103 is a yoke. A fixed iron piece 104 is fixed to the yoke 103. A drive lever 105 is rotatably attached to a base plate (not shown) by a shaft portion 105a. Reference numeral 106 denotes a drive pin fixed to the arm portion 105b of the drive lever 105, and the movable iron piece 10
It is slidably fitted in the first groove portion 101b, so that the drive lever 106 and the movable iron piece 101 move in conjunction with each other. 107 has one end attached to a ground plate (not shown) and the other end attached to the drive lever 105.
5 is a spring that is biased in the counterclockwise direction. 10
Reference numeral 8 is a stopper provided on a ground plate (not shown), which is a movable iron piece 1
01, and regulates the position of the movable iron piece 101 in the direction opposite to the arrow A.

The movable iron piece 101 has a recess 101a,
Further, the fixed iron piece 104 is provided with each convex portion 104a, and when the coil 102 is energized, the electromagnetic force generated here resists the biasing force of the spring 107,
The movable iron piece 101 is driven in the direction of arrow A until the concave portion 101a abuts the convex portion 104a of the fixed contact piece 104.
When the power supply is cut off, the spring 107 causes
It is configured to return to the state of.

The relationship between the stroke of the movable iron piece 101 of the electromagnet and the driving force generated by energization is as shown in FIG.

Characteristic G of this electromagnet is now shown. When the gap between the movable iron piece 101 and the fixed iron piece 104 is x, when the gap x becomes large, that is, when x _{2 in} FIG. 24, the generated driving force F _2a is when x is small, that is, x.
_The driving force F _1a generated in the case of ₁ is extremely small. Therefore, in order to generate a driving force of F ₂ (> F _2a ) with a stroke of x ₂ , this electromagnet must be configured to have the characteristic shown by H,
It was necessary to increase the number of turns of the coil 102 or the energizing current.

However, when a mechanism of this kind is incorporated into a camera or other electric appliances, the usable power source is limited. For example, when the power source is a battery, a large current causes a voltage drop, so that the current that can be passed is limited, and this method is not suitable after all.

In order to limit the current and generate a large driving force, there is a method of increasing the number of turns of the coil 102 as described above, but it is necessary to increase the number of turns without increasing the resistance of the coil 102. However, it is necessary to increase the winding diameter of the coil 102 to increase the number of turns. That is, the resistance per unit length of the winding of the coil 102 is reduced to increase the number of turns, and the resistance of the coil as a whole remains unchanged, thereby increasing the number of turns, thereby increasing the driving force generated by the electromagnet. Is the way. However, in this case, the coil 102 becomes very large and the compactness of the entire product is impaired, which makes it difficult to adopt.

A first object of the present invention is to provide a position information generator capable of generating a position signal at a finer pitch.

A second object of the present invention is to provide an electromagnetic drive capable of applying a large stroke and a large force to a driven member while preventing the device from becoming large and consuming a large current. An apparatus and a shutter driving device are provided.

[0021]

The present invention includes first and second aspects.
The tips of the comb teeth on the end faces of the respective yokes are arranged so as to face each other, and the tips of the comb teeth of the first yoke are all magnetized to the same magnetic pole, and the tips of the comb teeth of the second yoke are All of the tips are magnetized to magnetic poles different from the tips of the comb teeth of the first yoke, and the magnetic flux generated from the tips of the comb teeth of one yoke to the tips of the comb teeth of the other yoke is generated. , Are inverted at each pitch of the comb teeth of each yoke.

The movable iron piece is composed of at least a movable iron piece and a coil, and when the movable iron piece moves into the coil by energizing the coil, the strokes of the movable iron piece when the driving force in the direction is maximum are different from each other. A plurality of electromagnetic means configured as described above, a connecting member that connects the movable iron pieces to each other so that the movable iron pieces move in the same direction, and a control means that sequentially switches the energization of the coils of the plurality of electromagnetic means. The movable iron piece comprises at least a movable iron piece and a coil, and when the movable iron piece moves into the coil due to energization of the coil, the stroke of the movable iron piece when the driving force in the direction is maximum is different from each other. And a plurality of electromagnetic means configured as described above and the movable iron pieces are connected so that the movable iron pieces move in the same direction, and A first coupling member for moving together,
The stroke of each movable iron piece is provided with a control means that sequentially switches the energization of the coils of the plurality of electromagnetic means and a second connecting member that drives the blade for exposure control of the camera as the connecting member moves. Is small, and therefore, a plurality of electromagnetic means, which requires a small driving force, are sequentially switched and used, and the total stroke and driving force are applied to a driven member such as a shutter blade or other blade for exposure control. ..

[0023]

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

1 to 4 are views relating to a position information generating medium (device) of a first embodiment of the present invention. In FIG. 1, 201 is a ring-shaped permanent magnet magnetized in the axial direction. , The upper surface side is the N pole, and the lower surface side is the S pole. 202
Is a first auxiliary yoke made of a magnetically permeable material, and is a permanent magnet 20.
1 is in contact with the upper surface side. A second auxiliary yoke 203 made of a magnetically permeable material is in contact with the lower surface side of the permanent magnet 201. A cylindrical space ring 204 is made of a non-magnetic material and surrounds the permanent magnet 201.

Reference numeral 205 is a magnetically permeable material, and is a first yoke fixed to the outer peripheral portion of the space ring 204, and one end surface 205b of the first yoke is in contact with the first auxiliary yoke 202. A comb tooth portion 205a is formed on the other end surface. Reference numeral 206 is a magnetically permeable material, and is a second yoke fixed to the outer peripheral portion of the space ring 204, and one end face 206b is in contact with the second auxiliary yoke 203. A comb tooth portion 206b is formed on the other end surface.

FIG. 2 is a view showing a sectional view after assembly. The comb tooth portion 205a of the first yoke 205 and the comb tooth portion 206a of the second yoke 206 are opposed to each other in the radial direction, that is, in FIG. The details seen from the direction of arrow A are shown in FIG.

As shown in FIG. 3, the comb teeth 205a ₁ , 205a ₂ , 205a ₃ and 205a of the comb-tooth portion 205a.
₄ etc. and comb teeth 206a ₁ and 206a of the comb tooth portion 206a
The _2, 206a _3, 206a ₄ etc. are opposed so as to be positioned alternately.

In the magnetic circuit, the magnetic flux generated from the N pole of the permanent magnet 201 passes through the first auxiliary yoke 202 and the first yoke 2
A circuit is formed which jumps through 05 to the second yoke 206 and returns to the S pole of the permanent magnet 201 through the second auxiliary yoke 206.

An arrow in FIG. 3 shows how the magnetic flux flies from the first yoke 205 to the second yoke 206. Comb tooth 2
From 05a ₁ to the comb teeth 206a ₁ and 206a _{2 of the} south pole on the second yoke 206, from comb tooth 205a ₂ to comb teeth 206a ₂ and 206a ₃ , and from comb tooth 205a ₃ to comb tooth 206a ₃ . The magnetic flux is flying to 206a ₄ .

The permanent magnet 201, the first auxiliary yoke 202,
The second auxiliary yoke 203, the space ring 204, the first yoke 205, and the second yoke 206 are integrally formed,
These are combined to form a position information generating medium, and the amount of rotation of these is detected by the magnetic detection means 209 (see FIG. 2).

FIG. 4 is a sectional view taken along line BB in FIG.

The direction of the magnetic flux is the first yoke 205 in the circumferential direction.
And the second yoke 206 are inverted for each pitch of the comb teeth. When the position information generating medium is rotated, in order to detect the amount of rotation, the change in the direction of the magnetic flux for each pitch of the comb teeth is detected and changed by the preceding magnetic detecting means 209 such as a Hall element or an MR element. It will be done by counting the number of times.

Further, since the magnetic flux density increases as the magnetic flux emitted by the permanent magnet 201 increases, the magnetic flux having a high magnetic flux density is used for the permanent magnet 201, so that the magnetic detecting means including a Hall element or an MR element is used. Sufficient magnetic flux can be generated for detection at 209.

(Second Embodiment) FIGS. 5 and 6 are views relating to a position information generating medium of a second embodiment of the present invention.
The yoke and the second yoke are composed of a single component.

In these figures, 207 is a flexible printed circuit board, 207a is a base, which is made of polyimide resin. Reference numerals 207b ₁ and 207b ₂ are copper foil patterns, which have similar shapes to the first yoke 205 and the second yoke 206 of the first embodiment, as shown in FIG.
6 is a sectional view taken along line CC of FIG.

The surface 207c of the copper foil patterns 207b ₁ and 207b ₂ is plated with magnetically permeable nickel, which allows the space ring 20 shown in FIG.
When the flexible printed circuit board 207 is wound around and attached to the outer periphery of the first yoke 2, the first yoke 2 in the first embodiment is
05 and the second yoke 206 can perform the same function. Further, in order to protect the plating layer from mechanical damage, the copper foil patterns 207b ₁ and 207b ₂ are covered with a cover lay 207d made of a polyimide resin.

As described above, if the copper foil patterns 207b ₁ and 207b ₂ which function as the first yoke and the second yoke are formed on the same flexible printed board 207, the flexible printed board 207 is provided with the space ring 204.
When it is wound around and attached to the outer peripheral portion, the distance between the comb teeth of 207b ₂ which becomes the first yoke and the comb teeth of 207b ₁ which becomes the second yoke does not change, so that the assembly becomes easy.

(Third Embodiment) FIG. 7 is a diagram relating to a position information generating medium of a third embodiment of the present invention.

In FIG. 7, reference numeral 208 denotes a position information recording ring, which is shaded portions 208a and 208b on the outer peripheral portion.
The thin film magnet is formed by the sputtering method.
The portion 208c is masked during the sputtering process, and the thin film magnet is not shaped. A magnetic field is applied to this in the axial direction, that is, in the direction of arrow D to magnetize.

According to this, the magnetic flux flies between the comb teeth similarly to the first embodiment, and the rotation amount of the position information recording ring 208 can be detected by the magnetic detecting means 209 (not shown in FIG. 7). it can.

According to the above-mentioned first to third embodiments, two yokes having comb-teeth-shaped magnetic pole portions at one end are arranged so that their comb teeth are alternately opposed to each other, and one of them is arranged. Since the magnetic pole of the comb tooth portion of the yoke is different from the magnetic pole of the comb tooth portion of the other yoke, the position signal can be generated at a fine pitch. This makes it possible to significantly improve the detection accuracy of the rotation (movement) amount of the member to which the medium is attached.

Further, the magnetic flux density of the magnetic recording can be increased and the detection can be facilitated by the magnetic detection means such as the Hall element or MR element.

(Fourth Embodiment) FIGS. 8 to 16 are views relating to a shutter driving device according to a fourth embodiment of the present invention.

In these drawings, 1 is a base plate, 2 is a first yoke made of a highly magnetic permeable material fixed to the base plate 1, 3 is a first coil made of a conductive wire, and 4 is a permalloy fixed to the first yoke 2. It is a first fixed iron piece (see FIG. 10, etc.) made of a high magnetic permeability material such as.

A part of a first movable iron piece 12, which will be described later, is inserted into the first coil 3, and when the first coil 3 is energized, the first movable iron piece 12 generates a force to be further drawn into the coil. To do. That is, a known plunger device is formed from the first yoke 2, the first coil 3, the first fixed iron piece 4, and the first movable iron piece 12. This is hereinafter referred to as the first plunger device.

Reference numeral 5 is a second yoke made of a highly magnetic permeable material fixed to the base plate 1, 6 is a second coil made of a conductive wire, and 7 is a second magnetically permeable material fixed to the second yoke 5 such as permalloy. 2 Fixed iron pieces.

A part of the second movable iron piece 14 which will be described later is inserted into the second coil 6, and when the second coil 6 is energized, the second movable iron piece 14 generates a force to be further drawn into the coil. To do. That is, a known plunger device is formed from the second yoke 5, the second coil 6, the second fixed iron piece 7, and the second movable iron piece 14. This is hereinafter referred to as the second plunger device.

Reference numeral 8 is a third yoke made of a highly magnetic permeable material fixed to the base plate 1, 9 is a third coil made of a conductive wire, and 10 is a third magnetically permeable material fixed to the third yoke 8 made of a highly magnetic permeable material. 3 fixed iron pieces.

A part of a third iron piece 16 described later has entered the inside of the third coil 9. By energizing the third coil 9, the third movable iron piece 16 generates a force to be further drawn into the coil. To do. That is, a known plunger device is formed from the third yoke 8, the third coil 9, the third fixed iron piece 10, and the third movable iron piece 16. This will be referred to as a third plunger device.

The first, second and third plunger devices are arranged at equal intervals in the circumferential direction of the main plate 1.

A drive ring 11 is rotatably attached to the main plate 1. Reference numeral 12 denotes the above-mentioned first movable iron piece made of a highly magnetically permeable material, and the arm 11a of the drive ring 11.
On the other hand, as shown in FIG. 10 and the like, it is attached so as to be movable in the circumferential direction. A compression spring 13 is located between the first movable iron piece 12 and the arm 11a, and biases the first movable iron piece 12 in the counterclockwise direction with respect to the arm 11a.

Reference numeral 14 denotes the above-mentioned second movable iron piece made of a highly magnetically permeable material.
As shown in FIG. 10 etc., it is attached so as to be movable in the circumferential direction. A compression spring 15 is located between the second movable iron piece 14 and the arm 11b, and biases the second movable iron piece 14 in the counterclockwise direction with respect to the arm 11b.

Reference numeral 16 denotes the above-mentioned third movable iron piece made of a highly magnetic permeable material, which is used for the arm 11c of the drive ring 11.
As shown in FIG. 10 etc., it is attached so as to be movable in the circumferential direction. Reference numeral 17 denotes a compression spring, which is located between the third movable iron piece 16 and the arm 11c and biases the third movable iron piece 16 in the left rotation direction with respect to the arm 11c.

The compression springs 13, 15, 17 are
First movable iron piece 12, second movable iron piece 14, third movable iron piece 1
Since the 6 to the drive ring 11 is intended to hold the position shown in FIG. 10 is the initial state, described later, than the drive force generated in the first, second, third plunger device, namely the F ₂ It is very small.

Reference numerals 18, 19, 20 denote drive pins fixed to the drive ring 11, and reference numerals 21, 22, 23 denote shutter blades that also serve as apertures. Reference numeral 24 denotes a holding base plate fixed to the base plate 1, and holds the drive ring 11 with the base plate 1 with a vertical gap so as to regulate the drive ring 11 in the upward direction, and also the shutter blades also used as the diaphragm. 21, 22, and 23 are on the holding base plate 24. 25, 26 and 27 are presser base plates 2
The shutter blade 21 also serves as a fulcrum pin fixedly attached to No. 4 and has a hole 21a rotatably fitted in the fulcrum pin 25 and a long hole 21b slidably fitted in the drive pin 18. The aperture / shutter blade 22 has a hole 22a rotatably fitted in the fulcrum pin 26, and an elongated hole 22b slidably fitted in the drive pin 19. The aperture / shutter blade 23 has a hole 23a.
Is rotatably fitted to the fulcrum pin 27, and the long hole 23b is slidably fitted to the drive pin 20.

With this configuration, when the drive ring 11 rotates counterclockwise, the shutter blades 21, 22, 23
Rotates counterclockwise about the fulcrum pins 25, 26, 27 to form an opening. The opening area (opening diameter) is determined by the rotational position of the drive ring 11.

Reference numeral 28 denotes a blade pressing plate, which is a convex portion 28a, 28b.
It is fixed to the holding base plate 24 so as to have a predetermined gap with the holding base plate 24. Shutter blades 21,2
2, 23 are located in the gap, and the gap is the amount necessary for the shutter blades 21, 22, 23 to move.

Numeral 29 is a stopper fixed to the base plate 1, which is inserted into the long hole 11e of the drive ring 11 and is made into the long hole 1e.
By contacting the end face of 1e, the rotation of the drive ring 11 is regulated, especially the position in the right rotation direction with respect to the main plate 1.

Numeral 30 is a tension spring, one end of which is a base plate 1
1a portion and the other end are attached to 11d portion of the drive ring 11, and the drive ring 11 is urged in the right rotation direction with respect to the main plate 1. The urging force is on the order of "F _2/2". When the first, second and third coils are not energized, as shown in FIG. 10, the stopper 29 contacts the end face of the elongated hole 11e to regulate the position of the drive ring in the right rotation direction.

Reference numeral 31 is a photosensor, which has slits 11d,
The rotational position of the drive ring 11 is detected by detecting the 11e portion. The positional relationship between the slits 11d and 11e and the photo sensor 31 will be described later.

FIG. 9 is a sectional view of FIG.

FIG. 10 shows the drive ring 11 in the non-energized state in each coil, that is, the initial state and the three first, second and third drive rings.
FIG. 3 is a plan view showing the relationship with the plunger device of FIG.

In this initial state, in the second plunger device, the gap between the second movable iron piece 14 and the fixed iron piece 7 is "x ₃ " in terms of the rotation angle of the drive ring 11, and the third In the plunger device, the third movable iron piece 16
The gap between the fixed iron piece 10 and the fixed iron piece 10 is “2 × ₃ ” in terms of the rotation angle of the drive ring 11. In the first plunger device, the gap between the first movable iron piece 12 and the fixed iron piece 4 is the drive ring 11. It is "3 x ₃ " when converted to the rotation angle.

FIG. 14 shows the characteristics of the plunger device and corresponds to FIG. 24.

In FIG. 14, the horizontal axis represents the gap x between the fixed iron piece and the movable iron piece converted into the rotation angle of the drive ring 11, and the vertical axis represents the force F generated, which was used in this embodiment. All of the characteristics of the above plunger devices are shown as I, assuming that they are the same. Further, the required characteristics when using the conventional plunger device described in FIGS. 23 and 24 are indicated by H.

The driving force generated by the plunger device used in this embodiment is smaller than H, that is, much smaller than the conventional one.

A small plunger device having such characteristics is
It will be described below how to perform an operation equivalent to that of a conventional large-sized or large-current-consuming plunger device.

In the photo sensor 31, the drive ring 11 is shown in FIG.
From the position of _{0 x 3, 2x 3, 3x} 3 only in that the rotary slit 11d, and is configured so as to be discriminated by detecting 11e.

First, from the initial state of FIG. 10, the second coil 6
When the power is applied to the second plunger device, the second plunger device generates a driving force according to the characteristic shown in I of FIG. That is,
Since the maximum value of the gap between the second movable iron piece 14 and the second fixed iron piece 7 is “x ₃ ”, a driving force of at least F ₂ is generated, and the driving ring 11 resists the urging force of the spring 30. And rotate left. Here, as described above, by rotating the drive ring 11 counterclockwise, the shutter blades 21, 22, 2
The opening by 3 becomes larger gradually.

In the second plunger device described above, the second movable iron piece 1 is placed at the position where the drive ring 11 is rotated counterclockwise by "x ₃ ".
4 and the second fixed iron piece 7 contact each other, the drive ring 11
No driving force is generated to rotate the motor further. This state is the state shown in FIG.

Therefore, the photo sensor 31 is replaced by the slit 11
By detecting d, the drive ring 11 becomes “x₃ "Only times
It is determined that the coil has been turned over, and immediately the power to the second coil 6 is cut off.
At the same time, the third coil 9 is energized. Figure 1 at this time
As shown in FIG. 1, the third movable iron piece 16 and the third fixed iron piece 10
The gap is "x₃ ", So this third plunge
The device is the second plunger device shown in FIG.
At least F₂ Generates a driving force of
It The drive ring 11 is connected to the arm 11b and the second movable iron piece 14.
Rotate to the left while changing the relative position. On this occasion,
The compression spring 15 is charged, but the compression spring
The urging force of the ring 15 is F as described above. ₂ Compared to
Small and negligible.

The drive ring 11 is moved from the state of FIG. 11 to "x by the drive force generated by the third plunger device.
_It rotates counterclockwise by " ₃ " and becomes the state shown in FIG. When the photo sensor 31 is in the slit 11d and 1
It is determined by detecting the area between 1e.

In the state shown in FIG. 12, the third movable iron piece 16
And the third fixed iron piece 10 are in contact with each other, the third plunger device does not generate a driving force for further rotating the drive ring 11. Therefore, the power supply to the third coil 9 is immediately cut off, and at the same time, the power supply to the first coil 3 is performed. At this time, as shown in FIG. 12, the gap between the first movable iron piece 12 and the first fixed iron piece 4 is “x ₃ ”, so that the first plunger device is the same as the second plunger shown in FIG. As with the plunger device, a driving force of at least F ₂ is generated. The drive ring 11 rotates to the left while changing the relative position with the second movable iron piece 14 with the arm 11b and the relative position with the third movable iron piece 16 with the arm 11c. At this time, the compression springs 15 and 17 are charged, but the urging force of the compression springs 15 and 17 is extremely smaller than that of F ₂ as described above, and can be ignored.

The drive force generated by the first plunger device causes the drive ring to rotate counterclockwise from the state shown in FIG. 12 by "x ₃ ", resulting in the state shown in FIG. The fact that this state has been reached is determined by the photo sensor 31 detecting the slit 11e. When the power supply to the first coil 3 is cut off, the drive ring 11 is rotated clockwise by the urging force of the spring 30 and returns to the initial position, that is, the state shown in FIG.

FIG. 15 is a diagram showing the driving force generated by each plunger device for driving the drive ring 11 in the fourth embodiment.

The rotation angle of the drive ring 11 changes from "0" to "x".
During the ₃ "is a driving force second plunger device generates, between" x ₃ "of the" 2x ₃ "is a driving force the third plunger device generates, from the" 2x ₃ ""3x
_{During 3} ", the driving force is generated by the first plunger device.

FIG. 8 also shows the open area of the openings formed by the shutter blades 21, 22, and 23 with respect to the rotation angle of the drive ring by the broken lines. In the area of "S _1" in the rotational position of the "x _3", the rotational position of the "2x _3" "S _2"
To the area of, the area of "S _3" (i.e., fully opened state) in the rotational position of the "3x _3".

FIG. 16 is a block diagram showing the circuit arrangement of the shutter driving device in this embodiment.

In FIG. 16, reference numeral 32 is a control circuit for controlling the entire sequence including a microcomputer and the like, 33 is a photo sensor drive circuit for driving the photo sensor 31, and detecting the amount of rotation of the drive ring 11 from the signal from this. , 34 are coil energization control circuits for selectively energizing and de-energizing the first coil 3, the second coil 6, and the third coil 9 according to a signal from the control circuit 32.

In the fourth embodiment, since the small plunger device is arranged circumferentially, the diameter of the shutter device can be made small. Further, by arranging the plunger devices at equal intervals, the mass is balanced with respect to the center of rotation even when an external impact is applied to the shutter device, so that the drive ring does not rotate.
Further, the fixed iron piece is not always necessary, and even in the case of an electromagnet of a type having no fixed iron piece, the above effect can be obtained by sequentially using the range in which the generated driving force is large.

(Fifth Embodiment) FIG. 17 is a block diagram showing the circuit arrangement of a shutter drive device according to the fifth embodiment of the present invention. The same parts as those in FIG. 16 are designated by the same reference numerals.

In FIG. 17, reference numeral 35 is a voltage detection circuit,
This is a circuit that detects the voltage applied to both ends of the first coil 3, the second coil 6, and the third coil.

When the coil of the plunger device is energized when the power source is a battery, a counter electromotive force is generated when the movable iron piece comes into contact with the fixed iron piece, so that the voltage applied to both ends of the coil is momentarily lowered.

This state is shown in FIG. 18, where the horizontal axis represents the time from the current-carrying interval and the vertical axis represents the voltage applied across the coil.

The point at which the movable iron piece comes into contact with the fixed iron piece when a voltage of V ₁ is applied to both ends of the coil is indicated by arrow J. At this time, the voltage applied to the coil momentarily drops from V ₁ to V ₂ . This drop is detected by the voltage detection circuit 35 and the information is sent to the control circuit 32. The control circuit 32 thereby switches the energization to each coil via the coil energization control circuit 34.

With this structure, the photosensor 31 in the first embodiment is unnecessary.

(Sixth Embodiment) FIG. 19 is a block diagram showing the circuit arrangement of a shutter driving device according to the sixth embodiment of the present invention. The same parts as those in FIG. 16 are designated by the same reference numerals.

In FIG. 19, reference numeral 36 is a program change input means which is operated by the user, and which is composed of the position of the slide type switch and the number of times the button type switch is pushed, and the control circuit 32 is instructed to change the exposure program. Is to be entered.

The control circuit 32 responds to a command from the program change input means 36 at the time of the exposure operation 1),
Exposure control is performed according to one of the methods 2) and 3).

1) Only the second coil 6 is energized, the opening area is kept at S ₁ (see FIG. 20), and after a lapse of time when the exposure becomes appropriate at this opening area, the energization is cut off to control the exposure. The aperture characteristic at this time is shown by K in FIG.

2) The second coil 6 and the third coil 9 are sequentially energized, the third coil 9 is energized to maintain the opening area at S ₂ , and after the time when exposure becomes appropriate at this opening area has elapsed. , Turn off the power and control the exposure. The aperture characteristic at this time is shown by L in FIG.

3) The second coil 6, the third coil 9, and the first coil 3 are sequentially energized, the first coil 3 is energized to maintain the opening area at S ₃ , and the exposure becomes appropriate at this opening area. After a lapse of time, the power supply is cut off and exposure control is performed. The aperture characteristic at this time is shown by M in FIG.

With the above arrangement, the exposure control program can be easily changed.

According to the above fourth to sixth embodiments, a plurality of small-sized plunger devices are provided, the stroke at which the driving force generated by each of the plunger devices is maximized is changed, and the plunger devices are Since the drive unit is connected to drive each plunger device selectively,
An effect that a large force can be generated with a large stroke without increasing the energization current to the coil of the plunger device or increasing the number of coil windings, and the camera shutter drive device can be made compact. There is.

[0095]

As described above, according to the present invention,
The tips of the comb teeth on the end faces of the first and second yokes are arranged to face each other, and the tips of the comb teeth of the first yoke are all magnetized to the same magnetic pole. All the tips of the comb teeth of the yoke are magnetized to magnetic poles different from the tips of the comb teeth of the first yoke, and the tips of the comb teeth of one yoke to the tips of the comb teeth of the other yoke. The magnetic flux generated in the magnetic field is inverted at each pitch of the comb teeth of each yoke.

Therefore, it becomes possible to generate the position signal at a finer pitch.

Further, the movable iron piece is composed of at least a movable iron piece and a coil, and when the movable iron piece moves into the coil by energizing the coil, the stroke of the movable iron piece when the driving force in the direction is maximum is different. A plurality of electromagnetic means configured as described above, a connecting member that connects the movable iron pieces to each other so that the movable iron pieces move in the same direction, and a control means that sequentially switches the energization of the coils of the plurality of electromagnetic means. The movable iron piece comprises at least a movable iron piece and a coil, and when the movable iron piece moves into the coil due to energization of the coil, the stroke of the movable iron piece when the driving force in the direction is maximum is different from each other. And a plurality of electromagnetic means configured as described above and the movable iron pieces are connected so that the movable iron pieces move in the same direction, and A first coupling member for moving together,
The stroke of each movable iron piece is provided with a control means that sequentially switches the energization of the coils of the plurality of electromagnetic means and a second connecting member that drives the blade for exposure control of the camera as the connecting member moves. Is small, and therefore, a plurality of electromagnetic means, which requires a small driving force, are sequentially switched and used, and the total stroke and driving force are applied to a driven member such as a shutter blade or other blade for exposure control. .

Therefore, it is possible to apply a large stroke and a large force to the driven member while preventing the device from becoming large and consuming a large current.

[Brief description of drawings]

FIG. 1 is a perspective view of a position information generating medium (device) showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of FIG.

FIG. 3 is a diagram viewed from the direction of arrow A in FIG.

FIG. 4 is a sectional view taken along line BB in FIG.

FIG. 5 is a front view showing a main configuration of a position information generating medium (device) according to a second embodiment of the present invention.

6 is a sectional view taken along line CC of FIG.

FIG. 7 is a perspective view showing a main configuration of a position information generating medium (device) according to a third embodiment of the present invention.

FIG. 8 is a perspective view of a shutter driving device according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view of a shutter driving device according to the fourth embodiment of the present invention.

10 is a plan view showing a positional relationship between the plunger device and the drive ring in FIG. 8 in an initial state.

FIG. 11 is a plan view showing the positional relationship when the drive ring is rotated by “x ₃ ” from the state of FIG.

FIG. 12 is a plan view showing a positional relationship when the drive ring is rotated by “x ₃ ” from the state of FIG. 11.

FIG. 13 is a plan view showing a positional relationship when the drive ring is rotated by “x ₃ ” from the state of FIG.

14 is a diagram showing a relationship between a driving force and a stroke of the plunger device shown in FIG.

15 is a diagram showing characteristics of a driving force generated to rotate the drive ring of FIG.

FIG. 16 is a block diagram showing a circuit configuration of a shutter driving device according to a fourth embodiment of the present invention.

FIG. 17 is a block diagram showing a circuit configuration of a shutter drive device according to a fifth embodiment of the present invention.

18 is a diagram showing a characteristic of a voltage applied to the coil of FIG.

FIG. 19 is a block diagram showing a circuit configuration of a shutter drive device according to a sixth embodiment of the present invention.

20 is a diagram showing the characteristics of the opening area according to the operation of the program input changing means of FIG.

FIG. 21 is a plan view showing a main configuration of a conventional position information generating device.

FIG. 22 is a plan view showing a main part configuration of another conventional position information generating device.

FIG. 23 is a side view showing a main configuration of a conventional shutter drive device.

FIG. 24 is a diagram showing characteristics of the plunger device of FIG. 23.

[Explanation of symbols]

2, 5, 8 1st, 2nd, 3rd yokes 3, 6, 9 1st, 2nd, 3rd coils 4, 7, 10 1st, 2nd, 3rd fixed iron pieces 11 Drive rings 12, 14, 16 1st, 2nd, 3rd movable iron pieces 21, 22, 23 Shutter blades 31 Reflector 32 Control circuit 34 Coil energization control circuit 35 Voltage detection circuit 36 Program change input means 201 Permanent magnet 202 First auxiliary yoke 203 Second auxiliary Yoke 204 Space ring 205 First yoke 205a Comb tooth portion 206 Second yoke 206a Comb tooth portion 207 Flexible printed boards 207b ₁ and 207b ₂ Copper foil pattern 208 Position information recording rings 208a and 208b Portions where thin film magnets are formed

Claims (3)

[Claims] 1. A first yoke made of a magnetic material and having a comb-teeth-shaped end surface portion, and a second yoke made of a magnetic material and having a comb-teeth-shaped end surface portion are provided. The tips of the comb teeth on the end face are arranged to face each other, and the tips of the comb teeth of the first yoke are all magnetized to the same magnetic pole, and all the tips of the comb teeth of the second yoke are magnetized. Is
A position information generating device which is formed by magnetizing a magnetic pole different from the tip of the comb teeth of the first yoke. 2. The movable iron piece comprises at least a movable iron piece and a coil, and when the movable iron piece moves into the coil by energizing the coil, strokes of the movable iron piece when the driving force in the direction is maximum are different from each other. A plurality of electromagnetic means configured as described above, a connecting member that connects the movable iron pieces to each other so that the movable iron pieces move in the same direction, and a control means that sequentially switches the energization of the coils of the plurality of electromagnetic means. Equipped with an electromagnetic drive. 3. The movable iron piece comprises at least a movable iron piece and a coil, and when the movable iron piece moves into the coil by energizing the coil, the strokes of the movable iron piece when the driving force in the direction is maximum are different from each other. And a plurality of electromagnetic means configured as described above, and the movable iron pieces are connected so that the movable iron pieces move in the same direction,
A first connecting member that moves together with this, a control unit that sequentially switches the energization of the coils of the plurality of electromagnetic units, and a blade for exposure control of the camera that drives as the first connecting member moves. A shutter drive device including a second connecting member.