JPS63222336A - Optical system driving device - Google Patents

Abstract

PURPOSE:To suppress rolling and unnecessary oscillation of a mobile part by coupling wires, which support the mobile part of an optical system driving device, with a coupling member consisting of viscoelastic body. CONSTITUTION:One end of a wire 3 is coupled to one end of a mobile part 1 to which an objective lens 2 is set, and the order end 3a of the wire 3 is fixed and connected to a base not shows in the figure. Four wires 3 are coupled with a coupling member 10 consisting of a viscoelastic body like rubber, and wires 3 are interlocked to hole parts 12 of this member 10. Thus, though the part 1 tries to roll in the direction of an arrow C, the rolling motion is suppressed because the change of distance between coupling parts is stopped by the coupling member 10. Since the coupling member 10 consists of the viscoelastic body unnecessary oscillation generated in wires is damped.

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 example, to drive an objective lens of an optical head in an optical information recording/reproducing device.

[Conventional technology]

Conventionally, there has been an optical information recording and reproducing apparatus that records information on the recording medium and/or reproduces information recorded on the recording medium by irradiating a spot of laser light onto the surface of the information recording medium. It has 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 width of about 1 to 2 μm and a length of about 1 to 2 μm.
An information track consisting of a row of information pits of about 3 μm is formed in a spiral shape or a concentric circle shape. When reproducing the information recorded as the information pit string, the optical head irradiates the information track of the optical disk with a radar light beam in the form of a minute spot while rotating the optical disk. to scan. When the reflected or transmitted light of the light irradiated onto the optical disk surface is detected by a photodetector, the amount of light incident on the photodetector is determined depending on whether or not there is an information pit at the beam spot position. Optical properties change. In this way, a reproduced signal corresponding to the information bit string can be obtained.

In addition, in such an optical disk device, it is extremely important that the minute spot always accurately scan the information pit row on the recording medium. For this purpose, autofocusing that corrects a focus shift caused by warping of the recording medium and autotracking that corrects an irradiation position shift due to eccentricity of the recording medium, etc. are required. As a method to realize this autofocusing function and autotracking function,
Conventionally, an objective lens driving device as shown in FIG. 5 has been considered.

Incidentally, FIG. 5 is a schematic perspective view showing a conventional example of an objective lens driving device.

In the figure, 1 is a movable part. A coil (not shown) is attached to the outer periphery of the movable part 1. Furthermore, an objective lens 2 is attached to the upper part of the movable part 1. The movable part 1 has a through hole (not shown) along the optical axis direction of the objective lens 2.

Further, numeral 3 shown in the figure is a wire made of an elastic body. One end of the wire 3 is fixedly connected to the movable part 1 as shown, and the other end 3a of the wire 3 is fixedly connected to a base (not shown). There are a total of four wires 3 as shown in the figure.

The objective lens drive device configured as described above has a movable part 1
Due to the electromagnetic force of the current flowing through a coil (not shown) attached to the base and the magnetic force generated by the magnet fixed to the base (not shown), the track direction (direction A in the diagram) and the focus direction (direction B in the diagram) direction).

Ideally, the movable part 1 of such an objective lens driving device is driven in a parallel movement state in the track direction and the focus direction.

[Problem that the invention seeks to solve]

However, in the conventional example as described above, the movable part 1
has a degree of freedom in the rolling direction (direction of arrow C shown in FIG. 5), which causes problems such as deviation of the optical axis of the objective lens 2 (so-called tilting of the optical axis).

Further, in the conventional example described above, there is a vibration mode in which the wire 3 vibrates, and the movable part 1 becomes in a free vibration state due to disturbance etc., resulting in problems such as deviation of the optical axis.

〔the purpose〕

The present invention has been made in view of the problems of the prior art described above, and its purpose is to suppress unnecessary rolling motion of a movable part and to suppress the generation of unnecessary vibrations of the movable part. An object of the present invention is to provide an optical system driving device.

[Means for solving problems]

The above object, according to the present invention, includes a movable member holding an optical system, and means for supporting the movable member comprising a plurality of rod-shaped elastic members having one end fixed to the movable member and the other end fixed to a fixed member; and a driving means for driving the movable member; the supporting means is characterized in that at least two or more of the elastic members are connected between both ends thereof. This is achieved by an optical system driving device.

〔Example〕

Hereinafter, embodiments of the optical system driving device according to the present invention will be described specifically and in detail based on the drawings.

In this embodiment, an objective lens will be used as an example of the optical system.

FIG. 1 is a schematic perspective view showing a first embodiment of the optical system driving device according to the present invention, and FIG. 2 is a front view of the connecting member shown in FIG. 1.

In FIG. 1, members having the same functions as those shown in the conventional example of FIG. 5 are designated by the same reference numerals.

The embodiment shown in FIG. 1 will be described below.

In the figure, 1 is a movable part. A coil (not shown) is attached to the outer periphery of the movable part 1. Furthermore, an objective lens 2 is attached to the upper part of the movable part 1. The movable part 1 has a through hole (not shown) along the optical axis direction of the objective lens 2.

Further, numeral 3 shown in the figure is a wire made of an elastic body. One end of the wire 3 is fixedly connected to the movable part 1 as shown, and the other end 3a of the wire 3 is fixedly connected to a base (not shown). There are a total of four wires 3, and the wires 3 are provided so as to be parallel to each other.

Further, in the optical system driving device of the present invention, a connecting member 10 is provided approximately at the center of the four wires 3 so as to connect each wire 3.

The connecting member 10 is made of a viscoelastic material such as rubber.

FIG. 2 is a front view showing the above-mentioned connecting member 10. Second
As shown in the figure, the connecting member 10 has a rectangular shape. The four corners of the connecting member 10 have holes 12 into which the wire 3 is fitted. By fitting the wire 3 into the hole 12, the connecting member 10 and the wire 3 are often connected at the connecting portion 14 as shown.

Further, the angles θ and ψ (shown in FIG. 1) between the connecting member 10 and the wire 3 are engaged so that they can be easily changed.

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

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

In the above configuration, the optical system drive device is driven in the track direction by the electromagnetic force of the current flowing through the coil (not shown) attached to the movable part 1 and the magnetic force generated by the magnet fixed to the base (not shown). (A direction shown in FIG. 1) and a focus direction (B direction shown in FIG. 1). At this time, since the connecting member 10 is connected to the wire 3 as described above, the movement of the movable part 1 is not affected.

On the other hand, when the movable part 1 tries to rotate in the direction C (rolling direction) shown in the figure, the connection member 10 connected to the four wires 3 tries to change the distance between each connection part 14. In order to prevent this, the rolling motion of the movable part 1 is suppressed.

Furthermore, since the connecting member 10 is made of a viscous material such as rubber, unnecessary vibrations generated in the wire 3 to which the connecting member 10 is connected are damped.
Harmful vibrations can be suppressed.

Another embodiment of the present invention is shown in FIG.

Incidentally, FIG. 3 is a front view of a connecting member showing another embodiment of the present invention.

As shown in FIG. 3, the connecting member 20 of this embodiment is composed of a hole 22 made of a viscous material and an elastic member 24 that connects the hole 22. As shown in FIG.

By doing so, unnecessary rolling and vibration can also be suppressed.

Furthermore, another embodiment according to the present invention will be described using FIG. 4.

FIG. 4 is a schematic perspective view showing a second embodiment of the optical system driving device according to the present invention.

The embodiment shown in FIG. 4 shows an example in which the connecting member 30 is provided in the form of a sash.

If the connecting member 30 is intended to maintain the length of the member 30 when the movable member is in the neutral position,
The sash-shaped connecting members 30 do not need to be fixed to each other. (This is because the length of the diagonal line of the wire 3 tends to become shorter during rolling motion.) In the above embodiments, a viscoelastic material or a composite member of a viscous material and an elastic material is used as the connecting member. A connecting member made of an elastic body may also be used. However, in this case,
It cannot be denied that the vibration suppression effect is reduced.

Although the above-mentioned embodiment has a structure in which the movable part is held by four wires, it goes without saying that a holding member other than wires, such as a plate spring, etc., can have the same effect.

〔Effect of the invention〕

As described above in detail and specifically, by connecting the elastic members that support the movable part of the optical system drive device with the connecting member, it is possible to suppress the rolling motion of the movable part. Furthermore, by imparting viscosity to one connected member, unnecessary vibrations of the support means for supporting the movable part can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing a first embodiment of the optical system driving device according to the present invention, FIG. 2 is a front view of the connecting member shown in FIG. 1, and FIG. 3 is another embodiment of the connecting member. Front view showing 4th
The figure is a schematic perspective view showing a second embodiment of the optical system driving device according to the present invention, and FIG. 5 is a schematic perspective view showing a conventional example. DESCRIPTION OF SYMBOLS 1... Movable part, 2... Objective lens, 3... Wire, lO... Connecting member.

Claims (1)

[Claims] (1) A movable member holding an optical system; supporting means for the movable member consisting of a plurality of rod-shaped elastic members having one end fixed to the movable member and the other end fixed to a fixed member; and driving the movable member. In the optical system driving device having a driving means: The supporting means is characterized in that at least any two or more of the elastic members are connected between both ends thereof. Device.