JPS6275409A - Driving device - Google Patents

Abstract

PURPOSE:To reduce the weight of a driving device by constituting the device of N and S magnetic poles, a magnetic vibration part, driving coils, a supporting body, and a driven body. CONSTITUTION:The 1st and 2nd magnetic gaps 19, 20 are formed by the N pole consisting of a top plate 16 and the S pole consisting of a bottom plate 17 which are arranged as two steps in the vibration axis direction and the peripheral side of a cylindrical magnetic vibration part 18. The 1st and 2nd driving coils 21, 22 are wound around the peripheral side of the magnetic vibration part 18 in the magnetic gaps 19, 20 and the 1st and 2nd supporting bodies 23, 24 are fixed to both the end surfaces of the cylindrical magnetic vibration part 18. The driven body 2 is fixed to the inside of the magnetic vibration part 18 and reverse current flows are applied to two driving coils, driving force generated in the driving coils can be supplied to the driven body 27 without any transmission loss up to a high frequency range and the outer diameter of the whole driving device can be reduced. Thus, the weight of the device can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an autofocus device that applies mechanical vibration to a solid-state image sensor or an optical lens, and a driving device for an electromechanical acoustic transducer.

2. Description of the Related Art In recent years, with the spread of video tape recorders, video cameras have also come into use in general households. Along with this, products with autofocus functions have also appeared to make it easier for even males to use. Further, autofocus devices are also used in optical information reading devices such as compact disc players. Conventionally,
As an autofocus device, a method of moving a lens system (for example, Japanese Utility Model Application Publication No. 5.8-48035, Japanese Utility Model Application Publication No. 59-92437, etc.) or a method of moving a solid-state image sensor in the optical axis direction ( For example, JP-A-59-3751
Publication No. 0). In all of these, the lens system and the solid-state image pickup device are driven by the drive device itself used in conventionally known moving speakers and the like.

The conventional drive device as described above will be described below with reference to the drawings. FIG. 2 shows a sectional view of a conventional drive device.

In FIG. 2, 1 is an objective lens, 2 is a first bobbin connected to the objective lens 1, 3 is a second bobbin around which a drive coil 4 is wound, and 5 is a first bobbin. A connecting plate that connects the second bobbins 2 and 3, 6 a magnet, 7 a top plate fixed to the upper end of the magnet 6, 8 a bottom plate fixed to the lower end of the magnet 6 and having a center pole 9; Ball 9 and top plate 7 form an annular magnetic gap 1o. A drive coil 4 is arranged in the magnetic gap 10 . Reference numerals 11 and 12 designate a first frame and a second frame fixed to the upper end of the top plate 7 and the lower end of the bottom plate 8, and the first frame to which the objective lens 1 is connected.
a first support 13 fixed to both upper and lower end surfaces of the bobbin 2;
, O to which the outer peripheral portion of the second support body 14 is fixed.The operation of the drive device configured as described above will be described below. First, when a signal current is applied to the drive coil 4, the drive coil 4 obtains a driving force according to Fleming's left hand rule due to the magnetic flux in the magnetic gap 10, and vibrates in the optical axis direction.O Therefore, the drive coil 4 is wound. The first bobbin 2 connected to the second bobbin 3 via the connecting plate 5 also vibrates, and the first bobbin 2 fixed to both ends of the first bobbin 2 vibrates.
The second supports 13 and 14 support the vibrations.The objective lens 1 connected to the first bobbin 2 also vibrates in the same way as the drive coil 4.

Problems to be Solved by the Invention However, in the above configuration, the second bobbin 3, the connecting plate 6, and the third Unless the rigidity of the connecting plate 5 is extremely high, it will not be possible to extend good followability to high frequencies, and optimal focusing control will become impossible. Furthermore, in terms of shape, since the center ball 9 exists, concentric first and second bobbins 2 and 3 are required, and the diameter of the entire drive device is very large compared to the diameter of the lens, which is the driven object. This has led to problems such as increased size and difficulty in reducing weight.

In view of the above-mentioned problems, the present invention is a driving device for an autofocus device or an electromechanical acoustic transducer that applies mechanical vibration to a solid-state image sensor or an optical lens, which eliminates transmission loss from a driving force generation location to a driven object. The present invention provides a lightweight drive device that can transmit driving force, has a smaller outer diameter than conventional systems, and is lightweight.

Means for solving the problem In order to achieve this object, the drive device of the present invention has N and S magnetic poles arranged in two stages in the direction of the vibration axis, and a magnetic gap between the N and S magnetic poles. a cylindrical magnetic vibrating part arranged to form a cylindrical magnetic vibrating part, two active coils wound around the side surface of the cylindrical magnetic vibrating part and in the magnetic gap, and the cylindrical magnetic vibrating part. In order to support the cylindrical magnetic vibrating section, it is composed of two supporting bodies fixed to both end surfaces thereof, and a driven body fixed to the inner surface of the cylindrical magnetic vibrating section.

Function: With this configuration, N and S are arranged in two stages in the direction of the vibration axis.
The magnetic poles and the cylindrical magnetic vibrating part form a magnetic circuit, and magnetic fluxes in opposite directions flow through the two magnetic gaps. By winding drive coils in these two magnetic gaps and on the side surfaces of the cylindrical magnetic vibrating section, and passing currents in opposite directions, the drive coil and the magnetic vibrating section around which it is wound are directed in the same direction. With this driving force, it is possible to drive the driven object fixed to the inner surface of the magnetic vibrating part without transmission loss, and it is possible to improve followability up to high frequencies. Furthermore, since the center pole part seen in the conventional example is a magnetic vibrating part, the outer diameter of the entire drive device can be made smaller than in the conventional example, and the weight can therefore be reduced.

EXAMPLE Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a sectional view of a driving device in an embodiment of the present invention.

In Figure 1, 16 is an annular magnet, 16°17
018 is an annular top plate and an annular bottom plate fixed to the upper and lower end surfaces of the magnet 16, and 018 is a cylindrical magnetic vibrating section made of a magnetic material, and the outer peripheral side surface and the inside of the top plate 16 and the bottom plate 17 are connected to each other. First and second magnetic gaps 19 and 20 are formed with the circumferential side.

19.20 in this magnetic gap, and a cylindrical magnetic vibrating part 1
8 on the outer peripheral side. A second drive coil 21, 22 is wound thereon. Moreover, on both end surfaces of the cylindrical magnetic vibrating part 18,
A first support 23 and a second support 24 are fixed, and the outer peripheral end of each support is fixed to a frame 25.26 fixed to the magnet 15, the top plate 16, or the bottom plate 17. There is. 27 is a driven body fixed to the inner surface of the cylindrical magnetic vibrating part 18 ◎ The operation of the drive device configured as above will be explained below. The pole and bottom end face are set as the S pole.

At this time, the top plate 16 becomes the north pole and the bottom plate 17 becomes the south pole.Therefore, in the magnetic circuit including the magnetic vibrating section 18, a magnetic flux shown by a dotted line in FIG. 1 is generated. That is, magnetic flux is generated in the first magnetic gap 19 from the outside to the inside, and in the second magnetic gap 20 from the inside to the outside. Here's the first one.
When currents in opposite directions shown in the diagram are applied to the second drive coils 21 and 22, an upward driving force is generated in each drive coil according to Fleming's left-hand rule, and the coils vibrate. Therefore, the first. Second drive coil 21. The cylindrical magnetic vibrating part 18 around which Z2 is wound, and the driven body 27 fixed to its inner surface are also connected to the first. They vibrate in the same way as the second drive coils 21 and 22, and their entire vibration system consists of the first drive coil provided on both end surfaces of the magnetic vibrating section 18 and the frame 25.26. Second support 23
．． It is held at 24. The length of the cylindrical magnetic vibrating section 18 in the vibration axis direction is set to such a length that even when the magnetic vibrating section 18 vibrates, changes in the flow of magnetic flux caused by the magnet 15 can be ignored.

As described above, according to this embodiment, the N pole consisting of the top plate 16 arranged in two stages in the vibration axis direction, the S pole consisting of the bottom plate 17, and the outer circumferential side of the cylindrical magnetic vibrating section 18. , 1st. forming a second magnetic gap 19.20;
In the magnetic gap and on the outer circumferential side of the magnetic pole vibrating section 18, a first. The second drive coils 21 and 22 are wound around each other, and the first drive coils 21 and 22 are wound on both end surfaces of the cylindrical magnetic vibrating section 18. Second support 23
24, and the driven body 27 is fixed to the inner surface of the magnetic vibrating section, and by passing currents in opposite directions to the two drive coils, the driving force generated in the drive coils can be increased to a high frequency range. It can be supplied to the driven body 27 without transmission loss, and the outer diameter of the entire drive device can be made smaller than that of the conventional system, so that the weight can be reduced.

Furthermore, since the inner surface of the drive coil is a magnetic vibrating part 18 that is part of the magnetic circuit, the magnetic gap can be narrowed compared to the conventional example, and magnetic energy can be used effectively to improve conversion efficiency. Improvements can be made.

In this embodiment, the magnet 15, top plate 16, and bottom plate 17 are annular, but
The cross section perpendicular to the drive direction may have a generally sector-shaped cross section and may be arranged symmetrically with respect to the drive shaft, and is not particularly limited.

Effects of the Invention The present invention provides N and S magnetic poles arranged in two stages in the direction of the vibration axis, a cylindrical magnetic vibrating section arranged to form a magnetic gap with the N and S magnetic poles, and the cylinder. two drive coils wound around the side surfaces of the cylindrical magnetic vibrating section and in the magnetic gap; and two stray bodies fixed to both end surfaces of the cylindrical magnetic vibrating section to support the cylindrical magnetic vibrating section. By providing a driven body fixed to the inner surface of the cylindrical magnetic vibrating part, the driving force generated in the drive coil can be effectively transmitted to the driven body with good followability up to a high frequency range, Furthermore, compared to conventional methods, the overall shape of the drive device can be made smaller and lighter, and the spacing between the magnetic gaps can be narrowed, which improves the efficiency of electromechanical conversion and allows mechanical vibrations to be applied to solid-state image sensors and optical lenses. This makes it possible to realize an autofocus device and a driving device for an electromechanical acoustic transducer.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a drive device in an embodiment of the present invention;
FIG. 2 is a sectional view of a conventional drive device. 15...Magnet, 16...Top plate, 17...Bottom plate, 18...
...Magnetic vibrating part, 19...First magnetic gap, 2o...Second magnetic gap, 21...
First drive coil, 22... Second drive coil, 23... First support, 24... Second (D support, 25126... ...Frame, 27
・・・・・・Driven object.

Claims (1)

[Claims] N and S magnetic poles arranged in two stages in the direction of the vibration axis;
a cylindrical magnetic vibrating section disposed to form a magnetic gap with the magnetic pole of S; two drive coils wound around the magnetic gap on the side surface of the cylindrical magnetic vibrating section; In order to support the shaped magnetic vibrating part, two
1. A drive device comprising: a support body; and a driven body fixed to an inner surface of the cylindrical magnetic vibrating section.