JPS6342043A - Optical system driving device - Google Patents

Abstract

PURPOSE:To reduce the number of parts to facilitate the assembling work by molding the attaching part of a member, which constitutes a part of an optical system driving means, and an optical system integrally. CONSTITUTION:Bearing holes 16 and 22, a pin 18, a relay member 14, and a barrel 20 constitute a parallel link mechanism, and the barrel 20 is supported movably in the Y direction (focusing direction) by this link mechanism. An objective 24 which condenses a light beam into a spot on an information recording medium is provided on the upper end part of the barrel 20, and the objective 24 and the barrel 20 are formed integrally by molding. A focus driving coil 26 is wound around the barrel 20. A yoke 42 can be inserted to the part of the barrel 20 in an optical system driving device 2. Thus, the whole of the device is made 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 an optical head in, for example, an optical information recording/reproducing device.

[Prior Art] Conventionally, there has been an optical type in which a laser beam is irradiated onto the surface of an information recording medium in a spot shape to record information on the recording medium and/or to reproduce information recorded on the recording medium. 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 a recording medium on which information is reproduced by this optical disc device, has a radius of about 1 to 2 m and a length of 1 to 2 m.
An information track consisting of a row of information bits of about 3 gm is formed in a spiral shape or a concentric circle shape. When reproducing the information recorded as the information pit string, while rotating the optical disk, a minute spot of laser light beam is irradiated from an optical head onto the information track of the optical disk, and the information pit string is scanned by the beam spot. . The reflected light of the light irradiated onto the optical disk surface in this way,
Alternatively, when transmitted light is detected by a photodetector, the optical properties of the light incident on the photodetector change depending on whether an information pit exists at the beam spot position. In this way, a reproduced signal corresponding to the information pit string can be obtained.

In such an optical disk device, it is extremely important to always accurately scan the information pit row of the recording medium H with minute spots. To this end, autofocusing is required to correct focal shifts caused by warpage of the recording medium, and autotracking is required to correct irradiation position shifts due to eccentricity of the recording medium. As a method for realizing this autofocusing mechanism and autotracking function, an objective lens driving device 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 driving device includes a first leaf spring 71 whose one end is fixed to a fixed support part 70, a relay body 72 which is fixed to the other end of the leaf spring, and the relay body. The second leaf spring 73 is fixed to one end thereof, a movable body 74 is fixed to the other end of the leaf spring, and an objective lens 75 is held by the movable body. A tracking coil 76 is attached to the relay body 72, and a focusing coil 1L/77 is attached to the moving body 74. Part 1-
A magnetic field from a permanent magnet 78 is applied to the locking coil 76, and a magnetic field from a permanent magnet 79 is applied to the locking coil 77. The relay body 72 can move in the X direction based on the deformation of the first leaf spring 71, and the moving body 74 can move in the X direction based on the deformation of the second leaf spring 73. These movements are controlled by current flowing through the Okuki coils 76 and 77.

[One Problem to be Solved by the Invention] However, the conventional objective lens drive device as described above has a problem in that it has a large number of parts and is therefore troublesome to assemble.

[Objective] The present invention has been developed in view of the problems of the prior art described above, and its object is to provide an optical system drive device that has a small number of parts and is easy to assemble.

[Means for Solving the Problems] According to the present invention, the above object is achieved in that the mounting portion of the member constituting a part of the optical system drive child actor and the optical system are integrally molded. This is achieved by an optical system drive device with the following characteristics.

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

FIG. 1 is a perspective view showing an embodiment of the optical system driving el-m according to the present invention, 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 WIA moving device 2 according to the present invention has a base 4 made of a rectangular plate. A column 6 is rotatably connected to the right end of the top surface of the base as shown.

A pair of pivot bearings (only the upper bearing 8 is shown) is attached to the column, between which a second
As shown in the figure, a pot axis lO is arranged. The pivot axis is vertically arranged.

One end of an arm 12 extending horizontally is fixed in the center. A relay member 14 is fixed to the other end of the arm 12. 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. Further, one end of a pin 18 having appropriate rigidity is connected to each bearing hole 16, one in total, four in total. Each pin is arranged in parallel, and the other end of the pin has a cylindrical shape as shown! Q simple 20
The shaft is connected to bearing holes 22 provided at four ends of the shaft. The above-mentioned bearing holes 16 and 22, the pin 18, the middle a member 14, and the m-th 20th member form a parallel link mechanism.

The lens barrel 20 is supported movably in the Y direction (focusing direction) shown in FIG. 1 by the link mechanism.

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, a molded aspherical lens or the like (a spherical lens may also be used) is used. In addition, in the uninvented case, the objective lens 24 and the mirrors a, 1
20 is integrally formed by molding.

Furthermore, for m t, '+20, focus WIA is applied to the outer periphery.
A moving coil 26 is also wound around it. Moreover, the coil 26
A tracking drive coil 28 having a rectangular shape is fixed on the opposite side of the inner A member 14 .

Further, a yoke 30 having a figure 5 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 positions facing the tracking drive coil 2 described above. Further, a permanent magnet 34 is fixed to the center of the base 4 so as to correspond to the focus drive coil 26. An insect bezel 36 is fixed to the upper end of the magnet 34.

Further, as shown in FIG. 2, an opening 40 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, a yoke 42 having a cylindrical shape is provided around the opening 40 along the optical axis 38.

Also, the hollow rubber 44 shown in 'fs 21:'4 is arm 1.
It is provided to hold 2 in the middle.

The above is the explanation of the configuration of the optical system driving device 2 according to the present invention IJI
It is.

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

As described above, in the drive device 2 of this embodiment, the relay member 14, the mirror t'J20, the bottle 18, and the bearing holes 16 and 22 form a parallel link mechanism, and the lens barrel is Move in the Y direction to 17. As this driving means, in this embodiment, the focus! is wound around the lens barrel 20! This is done by using the % efficacy coil 26 and the permanent magnet/stone 34 fixed to the stand 4. That is, by passing a current through the coil 26, the lens barrel 20 is driven in the focus direction by electromagnetic interaction with the magnetic field of the permanent magnet 34.

Further, in this embodiment, the arm 12, the middle member 14, the bin 18, and the mta2o are swingably movable about the pivot shaft 10 in the X direction (tracking direction) shown in FIG.
It is set to 1. As the driving means, in this embodiment, the tracking wJA! is fixed on the focus driving coil 26! This is done by using the II coil 28 and the permanent magnet 32 fixed to the yoke 30. In other words, by passing a current through the coil 28, the lens barrel 20 is moved in the tracking direction by electromagnetic interaction with the magnetic field of the permanent magnet 32. It is driven by

As described above, the optical system driving device 2 of this embodiment can drive the objective lens 24 two-dimensionally by autofocusing control and autotracking control.

Furthermore, in this embodiment, since the yoke 36 and the permanent magnet 34 are located between the two upper and lower bins 18, they also have a mechanism as a position limiter for the objective lens 24 in the vertical direction. Further, the optical system driving device 2 according to the present invention has a mirror 0
Since the yoke 42 is made to be recessable in the 20th section, the entire device is compact.

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

Furthermore, in the above 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, but the present invention is not limited to this. Instead of a molded objective lens 11, as shown in the cross-sectional view of the objective lens in FIG.
The outer circumference f of the cylindrical flange portion of 0! Coil 11 to 11112
It may be of a type in which 4 windings are wound.

Furthermore, as shown in the exploded perspective view of the optical component in FIG.
An objective lens 120 and a ring-shaped member 12 integrally molded with the lens 120 and provided with a bearing 122.
4, and a ring-shaped member 1 having a bearing 126 in the same manner as described above.
An air-core coil 130 for focusing, which is wound and fixed in a cylindrical shape, is fixed between 11 and 2g, and an air-core coil 132 for tracking is placed on this coil 130. Optical parts made by attaching the i1 are also not applicable to the present invention.

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

[Effects of the Invention] As explained above in detail and concretely, the optical system and the mounting portion of a part of the means for driving the optical system of the unexploded 11 are integrally molded, so the parts It is possible to provide an optical system drive device that requires fewer parts and is easy to assemble.

[Brief explanation of drawings]

1 is a perspective view showing an embodiment of the optical system driving device according to the present invention, 2124 is a cross-sectional view thereof, FIG. 3 is a cross-sectional view of an objective lens, FIG. 4 is an exploded perspective view of optical components, FIG. 5 is a perspective view of a conventional objective lens driving device. 2...Optical system lol! h device 16.22...bearing hole 18...-bin 20...lens barrel 24...objective lens 26...focus drive coil 28...tracking drive coil 32.34...permanent Magnet 42... York agent Patent attorney Jo Taira Yamashita Figure 1 Figure 2 'f--38 Figure 3 Figure 4

Claims (2)

[Claims] (1) In an optical system driving device that drives an optical system in at least one direction, the mounting portion of a member that constitutes a part of the optical system driving means and the optical system are integrally molded. Features: Optical system drive device. (2) The optical system driving device according to claim (1), wherein the optical system driving means includes a coil and a means for generating a magnetic field that crosses the coil, and the coil is attached to the mounting portion. .