JPH07244234A - Electromagnetic driving device and lens driving mechanism using the same - Google Patents

Abstract

PURPOSE:To make the structure simple, to make the assembling work easy and to reduce the cost. CONSTITUTION:Notches 11, 11, 12 and 12 extending parallel with supporting shafts 5 are respectively formed at the parts of an inside yoke 10 and an outside yoke 8 opposed to the supporting shafts 5, and the coupling pieces 18 and 18 of a movable member 4 are projected to the outside of a yoke frame body 6 through the notches 11, 11, 12 and 12 of the yokes 10 and 8, and a bearing block 19 and a shaft guide part 22 are formed at one tip part and the other tip part of the coupling piece 18, respectively. The bearing block 19 is supported to be freely slidably by one supporting shaft 5 of a lens barrel and the shaft guide part 22 is engaged freely slidably with the other supporting shaft 5. tapless coil 15 and a coil bobbin 14 are positioned in magnetic field, and a lens 17 and a lens holder 16 are positioned inside the yoke 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel electromagnetic drive device and a lens drive mechanism using the electromagnetic drive device. More specifically, the invention relates to an electromagnetic drive device that axially slides a movable member that has a driven body in a cylindrical outer casing, and a lens drive mechanism that uses this electromagnetic drive device. It is suitable for use in a drive mechanism that drives a movable lens for focusing or a movable lens for zooming in a lens barrel, and has a simple structure and good assemblability, reducing cost. It is intended to provide a novel electromagnetic drive device that can contribute and a lens drive mechanism using the electromagnetic drive device.

[0002]

2. Description of the Related Art Generally, a lens barrel of a video camera or the like having an autofocus function and an electric zoom function has a driving means for moving a movable lens for focusing and a movable lens for zooming in its optical axis direction. Is provided. As this type of drive means, for example, an electromagnetic drive type actuator having a coil and a magnet,
That is, relatively many electromagnetic drive devices are used.

FIGS. 6 to 8 show an example a of an electromagnetic drive device introduced by the applicant of the present application as Japanese Patent Application No. 93856 in 1993 based on a request for size reduction and high magnification in the axial direction. Yes, it is for driving the focus lens.

The electromagnetic drive device a includes a fixing member c arranged in an outer casing b having a rectangular tube shape, and a state in which the fixing member c is not in contact with the fixing member c and is axially arranged with respect to the outer casing b. The outer casing b is provided with two support shafts e, e extending in parallel to the central axis of the outer casing b at the corners facing each other inside the outer casing b. It is fixed.

The fixing member c is a yoke frame f made of a magnetic material.
And magnets g fixed to the yoke frame f, ...
・ It is composed of and.

The yoke frame f has a rectangular shape which is one size smaller than the cross-sectional shape of the outer casing b and has a connecting plate h having a rectangular hole formed in the central portion thereof, and the connecting plate h is directed forward from four inner end edges of the connecting plate h. , And the outer yokes j, j, ... Protruding on the same side as the inner yokes i, i, ... From the four outer edges of the connecting plate h. And are integrally formed, and the magnets g, g, ... Are fixed to the surfaces of the inner yokes i, i, ... that oppose the outer yokes j, j ,. Thus, magnetic fields k, k, ... Are formed between the magnets g, g ,.

.. are formed between the inner yokes i and the inner yokes i adjacent to each other, and the gaps are formed between the outer yokes j and the outer yokes j adjacent to each other. m, m, ... Are formed.

The movable member d comprises a flat rectangular tubular coil bobbin n, a cylindrical lens holder o smaller than the coil bobbin n, a focus lens p supported by the lens holder o, and the like.

On the outer peripheral surface of the coil bobbin n, a winding groove extending in the axial direction is formed in a portion excluding both end edges in the axial direction, and the coil q is wound around the winding groove, and the coil q is wound. The generated coil bobbin n has the above-mentioned magnetic fields k, k, ...
.. and the outer yokes j, j, ... Inside the magnets g, g ,.

The lens holder o is formed in a flat cylindrical shape having an outer diameter smaller than the size inscribed in the inner yokes i, i, ... And at the front edge of the lens holder o at the four corners of the coil bobbin n. Connecting pieces r, r, ... Protruding outward are formed at opposing positions, and these connecting pieces r, r,
.. are connected to the coil bobbin n, and one set of two connecting pieces r, r extending in mutually opposite directions among the connecting pieces r, r ,. Further, it projects outward and bearing portions s, s are formed on the projecting portion.

The width of the connecting pieces r, r, ... When viewed in the axial direction is between the outer yokes j and j and the inner yoke i.
And i are formed to be slightly smaller than the widths of the gaps l and m formed respectively.

Reference numeral t denotes a moving magnet for position detecting means, which is attached to a bearing portion s positioned diagonally above the bearing portions s, s, and the moving magnets t are alternately magnetized in the longitudinal direction. It is a magnet, and is attached to a magnet mount u which is integrally projected from the upper end of the bearing s toward the rear.

The moving magnet t is inside the outer casing b, and cooperates with the magnetoresistive effect element v attached at a position corresponding to the moving magnet t to detect the position of the lens holder o. It functions as a position detecting means.

Such a lens holder o and the coil bobbin n are formed by winding a coil bobbin n in advance on the rear surface of the tip end of the connecting pieces r, r, ... Of the lens holder o by, for example, an adhesive. It is assembled by fixing.

Then, in order to assemble the movable member d into the outer casing b in which the fixed member c is arranged, the connecting pieces r, r, r of the movable member d,
... are the gaps 1, 2, between the inner yoke i and the outer yoke j.
.., m, m, ... While being inserted from the opening end side, the bearing parts s, s formed on the connecting pieces r, r are slidable on the support shafts e, e of the outer casing b. The movable member d is supported by the outer casing b so as to be slidable in the optical axis direction.

[0016]

However, in the above-mentioned conventional electromagnetic drive device a, since the coil q is formed by directly winding the wire rod around the coil bobbin n, the coil bobbin n and the lens holder o are formed. Had to be formed separately, and the number of parts and the number of assembling steps had to be increased, and there was a problem that the cost could not be reduced.

That is, the coil bobbin n or the lens holder o
The moving magnet t is often attached to the lens holder as described above, and since the moving magnet t is formed to extend in the axial direction, the lens holder o and the coil bobbin n are integrally formed. Then, the moving magnet t interferes with the work of winding the wire rod, and the wire rod cannot be wound around the coil bobbin n. Such a problem occurs especially when an attempt is made to automate the work of winding the wire around the coil bobbin n.

[0018]

In order to solve the above-mentioned problems, the electromagnetic drive device of the present invention has a cylindrical outer casing having a supporting shaft extending parallel to the axis of the outer casing, and a cylindrical outer casing. An inner yoke and a cylindrical outer yoke that surrounds the inner yoke are integrally or integrally connected at one end thereof, and are fixed to the inner yoke or the outer yoke and between the outer yoke or the inner yoke. A fixed member having a magnet for forming a magnetic field, a driven member holding member for holding a driven member, a coil wound in advance in an annular shape, and the coil in a state of being substantially concentric with the driven member holding member. A movable member having a connecting piece that is connected to the driven body holding member so as to surround the movable body and a bearing portion provided at an appropriate position of the connecting piece or the driven body holding member, and the fixed member is an outer casing. Place inside and at least inside yaw A notch extending parallel to the axis thereof is formed so that the driven body and the driven body holding member are located inside the inner yoke, and the connecting piece of the movable member is inserted into the notch of the inner yoke. Then, the coil is positioned in the magnetic field, and the bearing portion is supported by the support shaft.

A lens drive mechanism using the electromagnetic drive device of the present invention includes a lens barrel having a support shaft extending parallel to the optical axis, a cylindrical inner yoke, and a cylindrical outer yoke surrounding the inner yoke. A fixing member having a yoke frame body integrally or integrally connected at one end thereof and a magnet fixed to the inner yoke or the outer yoke to form a magnetic field between the outer yoke or the inner yoke, and the lens. A lens holder for holding, a coil wound in advance in an annular shape, a connecting piece for connecting the coil to the lens holder in a state of being substantially concentric with the lens holder and surrounding the coil, and an appropriate connecting piece or the lens holder. A movable member having a bearing portion provided at a position, the fixed member is arranged in the lens barrel, and a cutout extending at least in the inner yoke in parallel with the axis thereof is formed, and And the lens holder is positioned inside the inner yoke, the connecting piece of the movable member is inserted into the notch of the inner yoke to position the coil within the magnetic field, and the bearing portion is supported by the support shaft. It is a thing.

[0020]

Therefore, according to the electromagnetic drive device of the present invention, since the coil of the movable member is constituted by a so-called tapless coil in which the coil is wound in advance in an annular shape, there is no need to directly wind the wire on the coil bobbin. The shape of the movable member excluding the coil is not designed in consideration of directly winding a wire around the movable member, and the degree of freedom in designing the shape of the movable member excluding the coil can be increased, and the driven body The holding member, the connecting piece, the magnet mount, and the like can be integrally formed.

Further, since the tapless coil has its own shape, the coil bobbin is not an indispensable component as in the prior art, and the coil bobbin as a component is integrated with the driven body holding member and the connecting piece. Therefore, the number of parts and the number of assembling steps can be reduced and the cost can be reduced.

According to the lens driving mechanism using the electromagnetic driving device of the present invention, the above problems can be solved, and the movable lens for focusing and the movable lens for zooming in the lens barrel mounted on the video camera or the like. It is possible to provide a lens drive mechanism suitable for use as a drive mechanism for driving the.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The electromagnetic drive device of the present invention and a lens drive mechanism using the electromagnetic drive device will be described in detail below with reference to an example shown in the accompanying drawings.

The first embodiment is applied to an electromagnetic drive device for a focus lens of an inner focus unit mounted in a lens barrel of a video camera or the like.

The electromagnetic drive device 1 includes a fixing member 3 arranged in a cylindrical lens barrel 2, a non-contact state with respect to the fixing member 3, and an optical axis direction with respect to the lens barrel 2. And a movable member 4 supported slidably. The lens barrel 2 is located inside the lens barrel 2 at a position deviated by 180 ° from the center and is in close contact with the peripheral wall of the lens barrel 2 in a non-contact state. Two support shafts 5, 5 having a circular cross-sectional shape and extending parallel to the optical axis are fixed. Although not shown in the drawings, an inner flange protruding inward is formed at the rear end of the lens barrel 2, and the support shafts 5 and 5 project from the inner flange.

It should be noted that the lens barrel 2 is not limited to a cylindrical shape and may be a rectangular tube shape.

The fixing member 3 is a yoke frame 6 made of a magnetic material.
And magnets 7, 7 fixed to the yoke frame 6.

The yoke frame 6 is a cylindrical outer yoke 8 which is one size smaller than the lens barrel 2, an inner flange-like connecting plate 9 which is provided inward from the rear end edge of the outer yoke 8, and the connecting plate. A cylindrical inner yoke 10 that projects from the inner peripheral edge of the inner yoke 9 to the same side as the outer yoke 8 is integrally formed, and these yokes 8 and 10 are opened forward at positions shifted by 180 degrees from the center angle. Wide notches 11, 11, 12, 12 are formed.

These notches 11 and 11 and 12 and 12 are located on opposite sides of the central axis of the yoke, and
1 and 12 are arranged to face each other.

The yoke frame 6 is formed on the outer yoke 8, the inner yoke 10 and the connecting plate 9 as described above by subjecting a sheet metal material to so-called drawing, but the present invention is not limited to this, and the outer yoke formed as a separate body. The inner yoke and the connecting plate may be joined by welding or the like.

Since the outer yoke 8 and the inner yoke 10 have an arc-shaped cross section,
There is no possibility of bending to change the distance between the yokes 8 and 10.

The magnets 7, 7 have an arc-shaped cross section and are magnetized with different poles in the radial direction, that is, inside and outside, and are fixed to the inner peripheral surface of the outside yoke 8. As a result, a magnetic field 13 is formed between the magnet 7 and the inner yoke 10.

The fixing member 3 is fixedly arranged in the lens barrel 2 with the notches 11 and 11 of the outer yoke 8 facing the support shafts 5 and 5 of the lens barrel 2, respectively.

The movable member 4 is supported by a flat cylindrical coil bobbin 14, a tapless coil 15 fitted onto the coil bobbin 14, a ring-shaped lens holder 16 which is slightly smaller than the coil bobbin 14, and the lens holder 16. The focus lens 17 is included.

The inner diameter of the coil bobbin 14 is slightly larger than the outer diameter of the inner yoke 10, and the outer diameter of the lens holder 16 is slightly smaller than the inner diameter of the inner yoke 10. The lens holder 16 and the lens holder 16 are in a concentric position.
Are connected to each other at the front end edge of each of them by 180 degrees at the central angle, and are connected by outwardly projecting connecting pieces 18 and 18, respectively, so that the connecting pieces 18 and 18 project to the outside of the coil bobbin 14. The coil bobbin 14, the lens holder 16, and the connecting pieces 18, 18 are integrally formed.

The width of the connecting pieces 18, 18 as viewed in the axial direction is smaller than the width of the cutouts 11, 12 formed in the outer yoke 8 and the inner yoke 10, respectively.

A bearing block 19 is integrally formed at the tip of one of the connecting pieces 18, and an insertion hole 20 parallel to the axial direction is formed in the bearing block 19.
Bearing metals 21, 21 are press-fitted into the insertion hole 20 from the front-rear direction, and a groove-shaped shaft guide that is U-shaped when viewed from the axial direction and opens outward at the tip of the other connecting piece 18. Part 2
2 is formed, and the insertion hole 2 of the bearing block 19 is formed.
The distance between the center of 0 and the center of the shaft guide portion 22 is formed to be substantially the same as the distance between the axes of the support shafts 5 and 5.

The tapless coil 15 is formed by winding a wire into a coil shape in advance and maintaining its shape with an adhesive or the like, and its inner diameter is approximately the same as the outer diameter of the coil bobbin 14, or It is formed large,
The outer diameter of the magnets 7 is smaller than the inner diameters of the magnets 7.

The tapless coil 15 as described above is attached to the coil bobbin 14 with an adhesive or the like while being fitted onto the coil bobbin 14, so that the tapless coil 15 and the coil bobbin 14 are inside the yoke 13 in the magnetic field 13. 10 and the magnet 7 in a non-contact state.

In this embodiment, the coil bobbin 1
4 shows the tapless coil 15 fitted externally,
By doing so, the position of the tapless coil 15 can be stabilized. However, in the present invention, the coil bobbin is not an essential component, and the tapless coil 15 can be directly attached to the connecting piece with an adhesive or the like.

Then, in order to assemble the movable member 4 to the lens barrel 2 in which the fixed member 3 is arranged, the connecting pieces 18, 1 of the movable member 4 are assembled.
8 is an outer yoke 8 and notches 11, 11 of the inner yoke 10,
12 and 12 are inserted from the open end side thereof, and the bearing metals 21 and 21 of the bearing block 19 formed on the one connecting piece 18 are slidably fitted on the one supporting shaft 5 of the lens barrel 2. Further, the other support shaft 5 is sandwiched between the shaft guide portions 22 of the other connecting piece 18, whereby the movable member 4 is supported slidably in the optical axis direction with respect to the lens barrel 2.

At this time, the coil bobbin 14 and the tapless coil 15 are positioned between the inner yoke 10 and the magnets 7, 7, that is, in the magnetic field 13, and the lens holder 16 is positioned inside the inner yoke 10. .

The movable member 4 is slidably supported on the lens barrel 2 mainly by the bearing block 19 and the support shaft 5, and the shaft guide portion 22 is engaged with the support shaft 5 by the shaft. Functions as a detent in the direction of rotation.

Further, although the supporting shafts 5 and 5 have a circular cross section, the supporting shafts may have a single supporting shaft by making the sectional shape non-circular such as oval.

Further, although the support shafts 5 and 5 are arranged outside the outer yoke 8 in this embodiment, the present invention is not limited to this, and the support shafts may be arranged inside the inner yoke 10.
In this case, the notch formed in the yoke may be formed only in the inner yoke, and the bearing portion may be formed not only in the connecting piece but also in the lens holder.

Reference numerals 23 and 23 denote semi-arcuate plate-shaped sub-yokes made of a magnetic material. The sub-yokes 23 and 23 fix the movable member 4 after arranging the movable member 4 at a predetermined position with respect to the fixed member 3. The outer yoke 8 and the inner yoke 10 of the member 3 are attached to these so as to connect between the open ends of the members.

As a result, a closed magnetic path through which the magnetic fluxes from the magnets 7, 7 pass through the path of magnet 7-outer yoke 8-connecting plate 9 or sub-yoke 23-inner yoke 10-magnet 7 is formed, and the coil bobbin 14 is externally connected. The fitted tapless coil 15 is positioned on such a closed magnetic circuit.

Although the sub-yoke 23 is not always an essential component, the magnetic flux emitted from the magnet 7 is passed through the outer yoke 8 and then distributed between the connecting plate 9 and the sub-yoke 23 to eliminate saturation of the magnetic flux density. can do.

When the tapless coil 15 is supplied with the drive current, magnetic flux is generated from the tapless coil 15 in the direction corresponding to the direction of the drive current. A driving force in the axial direction is generated, and the driving force causes the lens holder 16 and the focus lens 17 to move integrally.

Reference numeral 24 is a position detecting means for detecting the position of the lens holder 16, and the position detecting means 24 is an alternate magnetized type attached to a bearing block 19 formed on the connecting piece 18 of the movable member 4. Moving magnet 25 (hereinafter referred to as “M
R magnet ". ) And a magnetoresistive effect element (hereinafter referred to as “MR sensor”) 26 attached to the inner peripheral surface of the lens barrel 2 facing the range in which the MR magnet 25 moves.

The MR magnet 25 is magnetized so that the magnetic poles are alternately different along the longitudinal direction of the MR magnet 25.
When the MR magnet 25 moves with the movement of 6,
The magnetic flux density reaching the MR sensor 26 changes and the MR sensor 2
Since the resistance value indicated by 6 changes, the current position of the lens holder 16 can be detected by counting this change.

The position detecting means 24 is, for example,
It is also possible to use known position detecting means including an inclined magnet and a Hall element.

In the above embodiment, the polarities of the magnets 7, 7 are made different in the radial direction,
Moreover, although the coil has one phase, the present invention is not limited to this, and the coils are multi-polarized so that the polarities are alternately different in the optical axis direction, and the coils are alternately phased in the optical axis direction with different phases. A structure having more than one phase (multi-phase linear motor) can also be used. In such a case, since the closed magnetic circuit is formed between the magnets of different poles adjacent to each other and the yokes facing each other, the outer yoke and the inner yoke are The magnetic flux is not concentrated on the connecting plate that connects the two, so that the thickness of the yoke can be reduced and the weight can be reduced, and an electromagnetic drive device that is long in the optical axis direction can be obtained accordingly. .

In the case of a polyphase linear motor, the magnetic flux passing through the coil changes as the coil moves.
The direction of the current supplied to the coil is switched according to the direction of the magnetic flux. Also, for example, when the coil has four phases,
Four wires may be wound around each coil to supply electric current to each coil with different current directions, or
It is also possible to reverse the winding direction of one wire and supply power to this.

In particular, in the case of making the coils multiphase,
When the wire is wound directly on the coil bobbin as in the conventional case, a partition plate for partitioning each phase must be formed on the coil bobbin in order to equalize the driving force of the coil in each phase. Only a coil with a small number of turns can be formed, and it has been enlarged in order to obtain a predetermined driving force. However, by using a tapless coil as in the present invention, a multiphase coil By forming them separately and arranging them side by side without a gap, it is possible to increase the magnetic efficiency and obtain a sufficient driving force in spite of the small size.

Further, in the above embodiment, an example in which the invention is applied to the drive mechanism of the movable lens (focus lens) of the inner focus unit mounted in the lens barrel of a video camera or the like, but the present invention is applicable. The present invention can be applied to a zoom lens drive mechanism that is a zoom lens, a biaxial actuator that moves a lens block in a so-called optical pickup device in one direction, and general moving devices that move other than the lens.

When the electromagnetic drive device of the present invention is applied as a moving device that moves a lens block in a biaxial actuator in one direction, it may be considered to dispose the objective lens of the lens block facing the notch formed in the yoke. To be

[0058]

As is apparent from the above description, the electromagnetic drive device of the present invention has an outer casing having a tubular shape and a support shaft extending parallel to the axis of the tubular body, a tubular inner yoke, and A cylindrical outer yoke that surrounds the inner yoke is integrally or integrally connected at one end thereof to a yoke frame body and is fixed to the inner yoke or the outer yoke to form a magnetic field between the outer yoke or the inner yoke. A fixed member having a magnet, a driven body holding member for holding the driven body, a coil wound in advance in an annular shape, and the coil so as to surround the driven body holding member in a substantially concentric state. An electromagnetic drive device comprising: a movable member having a connecting piece connected to a driven body holding member and a bearing portion provided at an appropriate position of the connecting piece or the driven body holding member, the fixed member Is placed in the outer case, Also has a notch formed in the inner yoke extending parallel to the axis thereof, the driven body and the driven body holding member are located inside the inner yoke, and the connecting piece of the movable member is connected to the inner yoke. It is characterized in that the coil is inserted into the notch to position the coil in the magnetic field, and the bearing is supported by a support shaft to slidably support the movable member in the outer casing.

Therefore, according to the electromagnetic drive device of the present invention, since the coil of the movable member is constituted by a so-called tapless coil which is wound in advance in an annular shape, there is no need to directly wind the wire on the coil bobbin, and therefore, The shape of the movable member excluding the coil is not designed in consideration of directly winding a wire around the movable member, and the degree of freedom in designing the shape of the movable member excluding the coil can be increased, and the driven body The holding member, the connecting piece, the magnet mount, and the like can be integrally formed.

Further, since the tapless coil has its own shape, the coil bobbin is not an indispensable component as in the prior art, and even if the coil bobbin is a component, it is integrated with the driven body holding member and the connecting piece. Therefore, the number of parts and the number of assembling steps can be reduced and the cost can be reduced.

A lens drive mechanism using the electromagnetic drive device of the present invention includes a lens barrel having a support shaft extending parallel to the optical axis, a tubular inner yoke, and a tubular outer yoke surrounding the inner yoke. A fixing member having a yoke frame body integrally or integrally connected at one end thereof and a magnet fixed to the inner yoke or the outer yoke to form a magnetic field between the outer yoke or the inner yoke, and the lens. A lens holder for holding, a coil wound in advance in an annular shape, a connecting piece for connecting the coil to the lens holder in a state of being substantially concentric with the lens holder and surrounding the coil, and an appropriate connecting piece or the lens holder. A lens drive mechanism using an electromagnetic drive device having a movable member having a bearing portion provided at a position, wherein the fixed member is arranged in a lens barrel, and at least the inner yoke has an axis thereof. A notch extending parallel to the inner yoke, the lens and the lens holder are located inside the inner yoke, and the coupling piece of the movable member is inserted into the notch of the inner yoke to allow the coil to move in the magnetic field. And the bearing member is supported by a support shaft to slidably support the movable member on the lens barrel.

Therefore, according to the lens driving mechanism using the electromagnetic driving device of the present invention, the above problems can be solved, and the movable lens for focusing and the movable lens for zooming in the lens barrel mounted on the video camera or the like. It is possible to provide a lens drive mechanism suitable for use as a drive mechanism for driving the.

In the above embodiment, the bearing part is formed on one of the two connecting pieces and the shaft guide part is formed on the other, but the present invention is not limited to this, and both bearing parts are formed. The point is that at least one of them has a bearing portion.

Further, in the above-mentioned embodiment, the notch for inserting the connecting piece is formed in both the inner yoke and the outer yoke. This is because the support shaft is arranged outside the outer yoke, and the support shaft is arranged in the inner yoke. In the case where it is arranged between the outer yoke and the outer yoke or inside the inner yoke, it is sufficient to form the notch only in the inner yoke.

Furthermore, in the above embodiment, the lens barrel, the fixed member, the movable member and the like have a circular cross section, but the present invention is not limited to this, and they are applicable to rectangular cross sections and other shapes. Of course, it can be done.

In addition, the concrete shapes and structures of the respective parts shown in the above-mentioned embodiments show only one example of the embodiment in implementing the electromagnetic driving device of the present invention and the lens driving mechanism using the electromagnetic driving device. However, the technical scope of the present invention should not be limitedly interpreted by these.

[Brief description of drawings]

1 shows an example of an embodiment in which the electromagnetic drive device of the present invention is applied to an electromagnetic drive device of a focus lens together with FIG. 2 to FIG. 5, which is an exploded perspective view.

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

FIG. 3 is a front view.

FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3, showing a state in which the focus lens is located at the frontmost position.

5 is a cross-sectional view taken along the line VV of FIG. 3, showing a state in which the focus lens is located at the rearmost position.

FIG. 6 shows an example of a conventional electromagnetic drive device together with FIGS. 7 and 8, and is an exploded perspective view.

FIG. 7 is a front view.

8 is a sectional view taken along the line VIII-VIII in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electromagnetic drive device (focus lens drive mechanism) 2 Lens barrel (outer casing) 3 Fixed member 4 Movable member 5 Support shaft 6 Yoke frame 7 Magnet 8 Outer yoke 10 Inner yoke 11 Notch 12 Notch 13 Magnetic field 14 Coil bobbin 15 Lens holder ( Driven object holding member) 16 Focus lens (driven object) 17 Coil 18 Connecting piece 19 Bearing block (bearing part) 22 Shaft guide part

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[Procedure amendment]

[Submission date] April 28, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction content]

Although the sub-yoke 23 is not always an essential component, the magnetic flux emitted from the magnet 7 is passed through the outer yoke 8 and then distributed to the connecting plate 9 and the sub-yoke 23 to suppress saturation of the magnetic flux density. And york
Use a strong magnet without increasing the thickness of the
Driving efficiency can be improved.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Oshige 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (14)

[Claims] 1. An outer casing having a tubular shape and having a support shaft extending parallel to the axis thereof, a tubular inner yoke, and a tubular outer yoke surrounding the inner yoke, are integrally formed at one end thereof. Alternatively, a fixed member having an integrally connected yoke frame and a magnet fixed to the inner yoke or the outer yoke to form a magnetic field between the outer yoke or the inner yoke, and a driven body holding for holding the driven body A member, a coil wound in an annular shape in advance, a connecting piece for connecting the coil to the driven body holding member in a state of being substantially concentric with and surrounding the driven body holding member, and the connecting piece or the driven body An electromagnetic drive device comprising: a movable member having a bearing portion provided at an appropriate position of a body holding member, wherein the fixed member is arranged in an outer casing, and at least an inner yoke with respect to an axis thereof. Has a notch that extends in parallel The driven body and the driven body holding member are positioned inside the inner yoke, the connecting piece of the movable member is inserted into the notch of the inner yoke to position the coil in the magnetic field, and An electromagnetic drive device in which a bearing member is supported by a support shaft and a movable member is slidably supported by an outer casing. 2. A support shaft provided on the outer casing is arranged outside the yoke frame, and the notch extends in parallel to the support shaft at portions of the inner yoke and the outer yoke facing the support shaft. Respectively, the bearing portion is formed at the tip of the connecting piece, and the connecting piece is inserted into the notches of the inner yoke and the outer yoke so that the bearing portion is located outside the yoke frame, The electromagnetic drive device according to claim 1, wherein a bearing member is supported by the support shaft and a movable member is slidably supported by the outer casing. 3. The inner yoke and the outer yoke are each formed in a concentric cylindrical shape, and the driven body is formed to have a substantially circular cross section, and the driven body holding member is provided. 3. The structure according to claim 1, wherein the coil is formed in an annular shape, and the coil is wound into a cylindrical shape concentric with the driven body and the driven body holding member.
The electromagnetic drive device according to. 4. The coil is externally fitted to a coil bobbin having an outer peripheral shape that is substantially the same as the inner peripheral shape, and the coil bobbin is attached to the connecting piece. The electromagnetic drive device according to claim 3. 5. The electromagnetic drive device according to claim 4, wherein the driven body holding member, the coil bobbin, and a connecting piece for connecting them are integrally formed. 6. The outer casing is provided with two support shafts, and the inner yoke and the outer yoke each have two notches.
It is formed in the part which opposes one support shaft separately, and
Magnets are respectively fixed to the inner yoke or the outer yoke at positions avoiding the above-mentioned notches, and the driven body holding member is provided with two connecting pieces, and at least one of the connecting pieces has a tip end. 2. A bearing portion is formed on the portion, the connecting pieces are projected to the outside of the yoke frame through the two notches, and the bearing portion is supported by the support shaft. The electromagnetic drive device according to claim 2, claim 3, claim 4, or claim 5. 7. Two support shafts are respectively arranged at positions substantially opposite to each other with the shaft center of the outer casing being sandwiched therebetween, and two notches are respectively formed on the two support shafts of the inner yoke and the outer yoke. It is formed on the opposite part, and
The two connecting pieces are provided so as to protrude at positions substantially opposite to each other with the axis of the driven body holding member interposed therebetween, and one of the connecting pieces has a bearing portion at one end portion and the other end portion. 7. A shaft guide portion is formed on the shaft, the bearing portion is supported by the one support shaft, and the shaft guide portion is slidably engaged with the other support shaft. Electromagnetic drive. 8. A lens barrel having a support shaft extending parallel to the optical axis, a cylindrical inner yoke, and a cylindrical outer yoke surrounding the inner yoke are integrally or integrally connected at one end thereof. Member that has a fixed yoke frame body and a magnet that is fixed to the inner yoke or the outer yoke and forms a magnetic field between the outer yoke or the inner yoke, a lens holder that holds the lens, and a coil that is wound in advance in an annular shape. And a movable member having a connecting piece for connecting the coil to the lens holder so as to surround the coil in a state of being substantially concentric with the lens holder, and a bearing portion provided at an appropriate position of the connecting piece or the lens holder. A lens driving mechanism using an electromagnetic driving device including: a fixing member disposed in a lens barrel, and a cutout extending at least in an inner yoke extending parallel to an axis thereof. The lens and the lens holder are located inside the inner yoke, the connecting piece of the movable member is inserted into the notch of the inner yoke to position the coil within the magnetic field, and the bearing portion is supported by the support shaft. A lens drive mechanism using an electromagnetic drive device in which a movable member is slidably supported by a lens barrel. 9. A support shaft provided on the lens barrel is arranged outside the yoke frame, and the notch extends in parallel to the support shaft at a portion of the inner yoke and the outer yoke facing the support shaft. Respectively, the bearing portion is formed at the tip of the connecting piece, and the connecting piece is inserted into the notches of the inner yoke and the outer yoke so that the bearing portion is located outside the yoke frame, 9. The lens drive mechanism using the electromagnetic drive device according to claim 8, wherein a bearing member is supported by the support shaft and a movable member is slidably supported by the lens barrel. 10. The inner yoke and the outer yoke are each formed in a concentric cylindrical shape, and the lens is formed so that its cross-sectional shape is substantially circular and the lens holder is formed in an annular shape. The lens drive mechanism using the electromagnetic drive device according to claim 8 or 9, wherein the coil is wound in a cylindrical shape concentric with the lens and the lens holder. 11. The coil bobbin is externally fitted to a coil bobbin having an outer peripheral shape substantially the same as the inner peripheral shape, and the coil bobbin is attached to the connecting piece. A lens drive mechanism using the electromagnetic drive device according to claim 10. 12. A lens drive mechanism using an electromagnetic drive device according to claim 11, wherein the lens holder, the coil bobbin, and a connecting piece for connecting them are integrally formed. 13. The lens barrel is provided with two support shafts, and the inner yoke and the outer yoke are respectively provided with two notches at portions respectively opposed to the two support shafts.
Two magnets are fixed to the inner yoke or the outer yoke at positions avoiding the above-mentioned notches, and two connecting pieces are projectingly provided on the lens holder, and at least one tip of these connecting pieces is provided. 9. A bearing portion is formed, and these connecting pieces are projected to the outside of the yoke frame through the two notches, respectively, and the bearing portion is supported by the support shaft. Item 9,
A lens drive mechanism using the electromagnetic drive device according to claim 10, 11, or 12. 14. Two support shafts are arranged at positions substantially opposite to each other across the optical axis of the lens barrel, and two notches are respectively formed on the two support shafts of the inner yoke and the outer yoke. Separately, the two connecting pieces are formed in opposite portions, and the two connecting pieces are provided so as to project at positions substantially opposite to each other with the axial center of the lens holder interposed therebetween. A shaft guide portion is formed at the other end of the shaft, the bearing portion is supported by the one support shaft, and the shaft guide portion is slidably engaged with the other support shaft. A lens drive mechanism using the electromagnetic drive device according to claim 13.