JPS62205536A - Optical system driving device - Google Patents

Abstract

PURPOSE:To execute focus control and tracking control with high accuracy by connecting the end of a supporting means to an optical system holder through a supporting shaft and a bearing and connecting another end rotatably to a base stand. CONSTITUTION:An objective lens holder 2 consists of a columnar member wound with a coil 18 on the outer peripheral part, an objective lens 1 and an objective lens holding member having two cylindrical bearings 3, 4 provided in the direction perpendicular (X direction) to the direction of optical axis (Y direction) of the lens 1. The first supporting means that controls movement in X direction of the holder 2 is constituted to shafts 5, 6 and bearings 3, 4, and guides 7, 8 and 9, 10 are provided on the end of shafts 5, 6, and the end of each of wires 11-14 that act as the second supporting means is fixed appropriately to a part of guides 7-10, and another end of each wire is fixed to a part of supporting shafts of turning means 19-22 consisting of supporting shafts and bearings provided on a base stand 23. Movement in X, Y directions is made by the electromagnetic force of current applied to coils 16, 18 and magnetic fields made by permanent magnets 15, 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Commercial Use] The present invention relates to an optical system driving device, and more particularly to an optical system driving device in which an optical system can be moved in a direction perpendicular to an optical axis direction and an original axis direction. INDUSTRIAL APPLICATION This invention is suitably used for optical information recording/reproducing apparatuses, such as an original disc.

[Prior art]

In recent years, with the development of the information society, research and development of optical information recording and reproducing devices that can store a large amount of information and record or reproduce desired information in a short time have been actively conducted.

A source disk device will be described below as an example of an optical information recording/reproducing device.

Generally, in an optical disk device, information pits having a width of about 1 to 2 μm and a length of about 1 to 3 μm are formed on an information recording medium. To reproduce information from this information pit, first a light beam is focused onto a minute spot using an objective lens.
Irradiates the information pit.

At this time, the reflected light or transmitted light from the information recording medium changes optically depending on the presence or absence of information bits.

By detecting this change with a photodetector, a reproduced signal corresponding to the information pits can be obtained.

In such a source disk device, it is extremely important that the information bit string on the information recording medium is scanned with minute spots accurately.

For this purpose, an autofocus function that corrects a focus shift caused by warpage of the information recording medium and an autotracking function that corrects an irradiation position shift caused by eccentricity of the information recording medium are required.

As a method of realizing this autofocus function and autotracking function, there is a driving method that supports the objective lens with a spring-like structure and uses the effect of electromagnetic force from an electromagnetic coil and a permanent magnet. Please be sure that the objective lens and drive unit are not being used.

FIG. 4 is a perspective view of a conventional objective lens driving device.

As shown in FIG. 4, the base 39 has a U-shaped yoke 4.
0 is fixed, and a permanent magnet 34 and a yoke 36 are fixed inside this yoke 40.

One end of the support spring 29.30 is attached to the yoke 40, and the other end is attached to the base 39 of the relay plate 37, which has a substantially square cross section.
fixed to the surface. One end of the support springs 27 and 28 is connected to the relay plate 3.
On the upper and lower surfaces of the base 39 of 7, there is an objective lens 25 for recitation.
The objective lens holder 26 is fixed 71 to the objective lens holder 26. The objective lens 25 focuses the laser beam onto the information recording medium surface. A coil 3 is connected between the support springs 27 and 28.
5 is fixed. This coil 35 is provided so as not to be in contact with the yoke 36 and to surround the yoke 36.

Support springs 27 and 28 of the objective lens holder 26 are fixed, and a coil 32 is fixed to the surface opposite to the next surface. Base 39
A U-shaped yoke 33 in which the permanent magnet 31 is fixed
is fixed, the coil 32 faces the permanent magnet 31,
The yoke 33 is provided with nine turns around the 10,000 vertical portions. The portion of the base 39 that faces the objective lens 25 has a through hole 3.
8 is open.

In the conventional objective lens and drive unit control with the above configuration, a magnetic circuit is configured by the permanent magnet 34, the yoke 36, and the yoke 40, and the magnetic field formed between the permanent magnet 34 and the yoke 36 is This is done by generating an electromagnetic force with the current flowing through the coil 35 and moving the objective lens holder 26 in a direction parallel to the base 39.

For focus control, a magnetic circuit is configured with a permanent magnet 31 and a yoke 33, and an electromagnetic force is generated by the magnetic field formed between the permanent magnet 31 and the yoke 33 and the current flowing through the coil 32, and the objective This is done by moving the lens holder in a direction perpendicular to the base 39.

[Problem that the invention seeks to solve]

However, in the conventional objective lens drive described above,
When performing focus control and tracking control in a high frequency range, since the objective lens holder is held by a plate-shaped support spring, cutting resonance occurs in the support spring, resulting in highly accurate focus control! Also, there was a problem that Tora and King Service could not be performed.

The present invention was made for the purpose of solving the problems of the above-mentioned conventional example.
The objective is to provide an optical system drive system that can drive a stable and highly accurate optical system.

[Means for solving problems]

The above problem is solved by an optical system holder that holds an optical system, and two mutually rotatable and slidable support shafts and bearings arranged in parallel in the optical axis direction of the optical system. (ii) supporting means for movably supporting the body in a direction perpendicular to the original axis direction; The optical system of the present invention includes a second supporting means that supports the holder so as to be movable in the direction of the base axis, and a driver W stage that moves the optical system holder in the direction of the optical axis and in a direction perpendicular to the base axis. [Function] The present invention connects one end of the second support means to the optical system holder via a support shaft and a bearing, and connects the other end to the base for one rotation. In particular, without deformation of the second support means,
Since the optical system holder can be moved in the original axis direction, vibrations of the optical system holder caused by focus control can be suppressed. Further, by configuring the support in the direction perpendicular to the original axis direction by the support shaft and the bearing, it is possible to suppress vibrations of the optical system holder due to tracking control.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

It should be noted that the optical system drive yJ of the present invention will be explained by taking an objective lens drive device as an example.

Figure 1 shows the objective lens drive of the present invention! FIG. 2 is a perspective view showing an embodiment of the I111I device.

In FIG. 1, the objective lens holder 2 includes a cylindrical member around which a coil 18 is wound, and an objective lens 1 provided on the top of the cylindrical member to focus laser light onto an information recording medium. and the objective lens 10 in the optical direction (first
Two cylindrical bearings 3 are arranged in parallel in the original direction in a direction perpendicular to the Y direction shown in the figure (hereinafter referred to as the Y direction) (X direction shown in Figure 1, hereinafter referred to as the X direction), and an objective lens holding member having a diameter of 4. A cylindrical permanent magnet 17 is fixed to the L-shaped base 23, and the objective lens holder 2 is arranged so that the inner circumference of the permanent magnet 17 and the coil 18 face each other. There is.

The bearings 3 and 4 are machined so that their inner surfaces have lubricating properties, and are rotatably and slidably supported @ (hereinafter referred to as shaft) 5
．． 6 is inserted. Figure 2 is a perspective view of the shaft 5.
The portion 5a that contacts the bearing 3 is coated with Teflon resin, thereby reducing shaft friction with the bearing 3. Note that the shaft 6 is made of the same wood as the shaft 5. In this embodiment, the first supporting means includes shafts 5, 6 and bearings 3, 4.
It consists of Guides 7.8 and 9.10 are provided at the ends of the shafts 5 and 6 to restrict movement kb of the objective lens holder 2 in the X direction. One end of second support means (hereinafter simply referred to as support means) 11, 12.degree. 13.14, such as a wire, is fixed to a part of the outer periphery of each guide 7.8, 9.degree. 10. The other end of the support means 11 to 14 is a rotation means 19, which is provided on the upright portion of the base 23 and includes a support shaft and a bearing.
It is fixed to a part of the outer periphery of the support shaft at 20, 21 and 22. A substantially rectangular coil 16 is solidly layered on the side surface of the objective lens holder 2 that faces the upright portion of the base 23 .

A permanent magnet 15 is fixed to the back plate 24 so as to face the coil 16, and the substrate 23 is fixed to the base 23.

The operation of the objective lens drive device having the above configuration will be described below.

3(a) is a side view of the objective lens driving device shown in FIG. 1, and FIG. 3(b) is a side view after displacement due to focus control. The objective lens holder 2 is slid in the X direction on the shafts 5 and 6 via the bearings 3 and 4 by the electromagnetic force of the current flowing in the Y direction and the magnetic field created by the permanent magnet 15. At this time, bearing 3.
4 and the shafts 5 and 6, the supporting means 11 to
14 hardly changes, suppressing the occurrence of unnecessary sub-resonance etc. in the high frequency range, and allowing highly accurate tracking servo to be applied.

As shown in FIG. 3(b), focus control is performed by moving the objective lens holder 2 in the Y direction using the electromagnetic force of the current flowing through the coil 18 and the magnetic field created by the permanent magnet 17. be exposed. In the figure, A is the objective lens holder 2.
The displacement of is. At this time, pair L, , , , ,
・,,, knee 1・=,・^1j, 1 mountain・un
j <・λ\ I ・(d+u+ C:
It moves on C with the rotation of the bearings 3 and 4 about the center and with the rotation of the rotation means 19 to 22. However, the supporting means 11 to 14 are only tilted at an angle θ, and there is almost no deformation accompanying the displacement of the objective lens holder 2 in the Y direction. That is, the objective lens holder 2 is supported by the four support means 11 to 14 forming the parallel linkage, and as described above, the support means 11 to 14 are not deformed, so the optical glaze does not fall. Furthermore, since the occurrence of unnecessary sub-resonance in the high frequency range can be suppressed, accurate and stable focus servo can be applied.

〔Effect of the invention〕

As explained in detail above, in the optical system and work device according to the present invention, one end of the second support means is connected to the optical system holder via the support hl and the IM receiver, and the other end is rotatable. By connecting it to the base, the optical system holder can be moved in the light 411 direction without deforming the second support means. In addition, since the support in the direction perpendicular to the original axis is grooved between the support shaft and the bearing, it is possible to suppress the vibration of the optical system holder that permeates tracking control. Even in the frequency range, sub-resonance can be suppressed and accurate focus illumination and tracking control can be performed.

[Brief explanation of drawings]

Figures 1 and 1 are perspective views showing one embodiment of the objective lens driving device of the present invention. FIG. 2 is a perspective view of the shaft used in the above embodiment. FIG. 3 is an explanatory diagram of the operation of the objective lens driving device of the above embodiment. FIG. 4 is a perspective view of a conventional objective lens 11 movement device. 1... pair (r cremme, 2... objective lens holder,
3゜4... Bearing, 5, 6... Shaft, 7, 8, 9.10
...Guide, 11,12,13,14...Supporting means, 19°20.21.22...Rotating means, 23...
A settlement. Figure 3 Figure 4

Claims (1)

[Claims] An optical system holder holding an optical system, and two sets of mutually rotatable and slidable support shafts and bearings are arranged in parallel in the optical axis direction of the optical system, and the optical system holder holds an optical system in the optical axis direction. a first support means movably supporting the optical system holder in a vertical direction; one end fixed to the first support means and the other end rotatably connected to the base; An optical system drive device comprising a second support means that supports the optical system holder so as to be movable in the axial direction, and a drive means that moves the optical system holder in the optical axis direction and in a direction perpendicular to the optical axis.