JPS6342044A - Optical system driving device - Google Patents

Abstract

PURPOSE:To make a device small in size and compact by arranging a holding body in a focusing magnetic field generating means formed into a cylinder having a notched part in a part and arranging a tracking magnetic field generating means correspondingly to the notched part. CONSTITUTION:A focus driving coil 26 is wound around a barrel 20, and a rectangular tracking driving coil 28 is stuck to the face opposite to the face of the coil 26 facing a relay member 14. Two permanent magnets 32 are stuck to the position facing the tracking driving coil 28, and a permanent magnet 34 which has the notched part in a part and is formed into a cylinder is stuck in the center of a base 4 correspondingly to the focus driving coil 26. The holding body is arranged in the space in the cylindrical magnet, and the magnetic field generating means which generates a magnetic field traversing the tracking control coil is arranged in the notched part. Thus, the whole of the device is made small in size and compact.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical system drive device that is suitably used for driving an objective lens of a light vent in, for example, an optical information recording/reproducing device.

[Prior Art] Conventionally, a laser beam is irradiated in a spot on the surface of an information recording medium to record information on the recording medium and/or to reproduce information recorded on the Qbx body. Optical information recording and reproducing devices have been put into practical use.

An example of such a device is an optical disk device. The optical disc, which is the recording medium on which information is reproduced by this optical disc device, has a radius of about 1 to 2 gm and a length of about 1 to 2 gm.
An information track consisting of a string of information bits of about 3 am is formed in a spiral shape or a concentric circle shape. When reproducing the information recorded as the information pit string, the optical disc is rotated and light is transmitted to the information track of the optical disc...? A laser beam is irradiated from the board in the form of a minute spot, and the information pit row is scanned by the beam bond. When the reflected or transmitted light of the light irradiated onto the optical disk surface is detected by a photodetector in this way, the amount of light incident on the photodetector depends on whether or not there is an information pit at the position of the beam substrate. Optical properties change. Thus,
It is possible to obtain +1) raw signals corresponding to the information bit string.

In such an optical disk device, it is extremely important to always accurately scan a minute spot of information pit rows on a recording medium. For this purpose, autofocusing is required to correct focal shifts caused by warpage of the recording medium, and autotracking is required to correct deviations in the irradiation position due to eccentricity of the recording medium. As a method for realizing the autofocusing and autotracking functions, an objective lens WJA mechanism δ as disclosed in Japanese Patent Application Laid-Open No. 57-103131 has been considered.

FIG. 5 is a perspective view of the objective lens driving device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 57-103131.

As shown in the figure, this conventional objective lens drive device d includes a first leaf spring 71 fixed at one end to a fixed support 70, a relay body 72 fixed to the other end of the leaf spring, and The second leaf spring 73 has one end fixed to a relay body, a movable body 74 to which the other end of the leaf spring is fixed, and an objective lens 75 held by the movable body. A tracking coil 76 is attached to the relay body 72, and a focusing coil 77 is attached to the moving body 74. A magnetic field from a permanent magnet 78 is applied to the tracking coil 76, and a magnetic field from a permanent magnet 79 is applied to the focusing coil 77. The relay body 72 can move in the X direction based on the deformation of the leaf spring 71 of il, and the moving body 74 can move in the y direction based on the deformation of the second leaf spring 73. These movements are controlled by the current flowing through the first coils 76 and 77.

[Problems to be Solved by the Invention] However, in the conventional objective lens driving device δ as described above, the coil 77, which is a means for driving the objective lens 75 in the focusing direction, and the magnetic field that crosses the coil are Since the magnet 79 that generates the magnetic field, the coil 76 that is a means for driving the objective lens 75 in the tracking direction, and the magnet 78 that generates a magnetic field that crosses the coil are arranged separately, the objective lens driving device as a whole It was difficult to make the device smaller and more compact.

[Objective] The present invention has been made in view of the problems of the prior art described above, and its object is to provide an optical system drive device that can be made smaller and more compact.

[Means for Solving the Problems] According to the present invention, in an optical system driving device for driving an optical system in both a focusing direction and a tracking direction, the optical system includes a focusing control coil and a focusing control coil. The tracking control coil is held by a cylindrical holder provided with a means for generating a magnetic field across the focusing control coil and a means for generating a magnetic field across the tracking control coil. The focusing magnetic field generating means has a cylindrical shape with a notch at ~, and the holding body is disposed inside the cylindrical shape and corresponds to the notch. This is achieved by an optical system driving device characterized in that the tracking magnetic field generating means is disposed at a position.

[Example] Hereinafter, an example according to the present invention will be described specifically and in detail based on the drawings.

Figure 1 shows the optical system according to the present invention! FIG. 2 is a perspective view showing an embodiment of the movement device, and FIG. 2 is a sectional view thereof. Note that this embodiment is applied to an objective lens drive of an optical information recording/reproducing device.

As shown in the figure, the optical system W film device 2 according to the present invention has a base 4 made of a rectangular plate. A column 6 is fixedly connected to the right end of the illustrated L surface of the base.

The column has a pair of pivot bearings (only the upper bearing 8 has 1.
4) are attached, between which a pot sleeve 10 is arranged as shown in FIG. The pivot shaft is arranged directly at +p, and one end of a horizontally extending arm 12 is fixed to the center thereof. Arm 12
A relay member 14 is fixed to the other end. The relay member 14 has a rectangular shape, and one bearing hole 16 is installed at each corner, a total of four bearing holes 16. Furthermore.

One end of a pin 18 having appropriate rigidity is connected to each bearing hole 16, for a total of four pins. The bins are arranged in parallel, and the other ends of the bins are connected to bearing holes 22 provided at four ends of a cylindrical lens barrel 20, as shown. The above-mentioned bearing hole 16
and 22, the bottle 18, the relay member 14, and the lens barrel 20
and form a parallel link mechanism. By means of the link mechanism, the mirror t320 is supported by the mirror 2 without being able to move in the Y direction ( ) direction shown in FIG. 1 .

Further, as shown in the figure, an objective lens 24 is provided at the upper end of the lens barrel 20 to make the light beam into a spot shape on the information recording medium. As the objective lens, for example, a molded aspherical lens cap (a spherical lens may also be used) is used. Further, in this embodiment, the objective lens 24 and i
The Q lens barrel 0 is integrally formed by molding. Furthermore, a focus drive coil 26 is wound around the outer periphery of the lens barrel 20. Further, on the opposite side of the coil 26 to the relay member 14, a tracking drive coil 28 having a rectangular shape is fixed.

Further, a yoke 30 having an L-shape is fixedly connected to the end of the base 4 on the opposite side to the side where the support column 6 is provided. Two permanent magnets 32 are fixed to the yoke at a position facing the above-mentioned tracking tJA driving coil 28. Further, a permanent magnet 34 having a cylindrical shape and having a notch in a portion is fixed to the center of the base 4 so as to correspond to the focus drive coil 26.

A yoke 36 is fixed to the upper end of the magnet 34.

Further, as shown in FIG. 2, an aperture fiB40 is provided in a portion of the base 4 located in the direction in which the optical axis 38 of the objective lens 24 extends. Furthermore, the optical axis 3 is located above J4 of the opening 40.
A yoke 42 having a cylindrical shape is provided along the line 8.

Further, a neutral rubber 44 shown in FIG. 2 is provided to hold the arm 12 in a neutral position.

This concludes the description of the configuration of the optical system driving device 212 according to the present invention.

Next, the operation of the drive device having the above configuration will be explained.

As mentioned above, in the transfer device fi2 of this embodiment, the relay member 14 and! The a cylinder 20, the bottle 18, and the bearing holes 16 and 22 form a parallel link m configuration, and the lens barrel is movable in the Y direction shown in the figure. As this driving means, in this embodiment, the focus! is wound around the lens barrel 20! ! l
iI dynamic coil 26 and permanent magnet 3 fixed to base 4
4, that is, the coil 26 is set to '$, fR,
The lens barrel 20 is driven in the focus direction by electromagnetic interaction with the magnetic field of the permanent magnet 34.

Also: 4. In the embodiment, the arm 12, the relay member 14, the bottle 18, and the mirror 7320 are not able to swing around the pivot shaft 10 in the X direction (tracking direction) shown in FIG. As this driving means, in this embodiment, the focus driving coil 26, the tracking driving coil 28 fixed to the L, and the permanent magnet 32 fixed to the yoke 30 are used. By causing the current to flow, the mirror f320 is driven in the tracking direction by electromagnetic interaction with the magnetic field of the permanent magnet 32.

As mentioned above, the optical system drive device of this embodiment? 12 can move the objective lens 24 two-dimensionally by autofocusing control and autotracking control.

In addition, in this embodiment, the yoke 36 and the permanent magnet 34 are
Since it is located between the bins 18 that have two bottles each,
It also has a moat as a position limiter for the objective lens 24 in the vertical direction. Furthermore, since the optical system driving device 2 has a yoke 42 that can be inserted into the lens barrel 20, the entire device is compact.

Furthermore, in the uninvented optical system drive device, the optical system is held by a cylindrical holder provided with both a coil for focus sync control and a coil for tracking control; The magnetic field generating means that generates a magnetic field that crosses the coil has a cylindrical shape with a notch in a part, and the above-mentioned holder is arranged in the inner gap of the T1 shape, and the holder is arranged in the inner gap of the T1 shape. Is there a magnetic field generating means that generates a magnetic field that crosses the coil for tracking control? It is possible to make the entire Ta smaller and more compact.

Furthermore, according to the present invention, efficient magnetic field application becomes possible.
Big wIA! h power can be obtained.

This concludes the description of the embodiments of the present invention.

Furthermore, in the above-described embodiment, the objective lens 24 and the lens barrel 20 are integrally formed by molding, and the focusing coil 26 is wound around the outer periphery of the lens barrel. The objective lens 11 may be molded as shown in the cross-sectional view of the objective lens in FIG.
A type in which the coil 114 is wound around the outer circumferential portion 112 of the cylindrical flange portion of 0 is suitable.

Furthermore, as shown in the exploded perspective view of the optical component in FIG. An air-core coil 130 for orcus (which is wound and fixed in a cylindrical shape) is fixed between the link-like member 128 provided with the bearing 126, and this coil 130
An optical component formed by fixing an air-core coil 132 for tracking to K is also applicable to the present invention.

Furthermore, in the above-described embodiment, a parallel link mechanism using four bearing holes 16 and 22 and four pins 18 is used as a method for supporting the objective lens 24, but the present invention is not limited to this. Instead, it is also applicable to other support methods using plate springs, coil springs, or elastic members such as rubber.

[Effects of the Invention] As described above in detail and specifically, the present invention provides an optical device that can be made lightweight and compact, and can also apply a magnetic field efficiently and obtain a large driving force. System wA
A corner device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the optical system driving device according to the present invention, FIG. 2 is a sectional view thereof, FIG. 3 is a sectional view of an objective lens, and FIG. 4 is an exploded side view of optical components. , FIG. 5 is a perspective view of a conventional objective lens drive 922. 2... Optical system drive device 16.22... Bearing hole 18... Bin 20... Cylinder 24... Objective lens 26... Focus drive coil 28-1 - Racking positive drive coil 32.34 ...Kiku magnet 42...Yoke Fig. 1 Fig. 2 Fig. 1'-38 Fig. 3 Fig. 4 Fig. 5

Claims (1)

[Claims] (1) In an optical system drive device that drives an optical system in both the focusing direction and the tracking direction; the optical system is held by a cylindrical holder that is provided with both a focusing control coil and a tracking control coil. A means for generating a magnetic field that crosses the coil for focusing control and a means for generating a magnetic field that crosses the coil for tracking control are provided, and the focusing magnetic field generating means has a notch in a part. The holder is arranged inside the cylindrical shape, and the tracking magnetic field generating means is arranged at a position corresponding to the notch. , optical system drive device.