JPS6120232A - Objective lens driving device of optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a miniaturized and highly accurate objective lens driving device whose number of manufacturing processes is reduced, by fixing a bobbin to an objective lens holder after winding a coil for focussing and another coil for track around the bobbin, with the coils intersecting each other at almost right angles. CONSTITUTION:Two magnets 107 are arranged in such a way that the objective lens 1 side of the magnets 107 can become the same is polarity when two coils for focussing 105 are conducted and, since electric currents are made to flow through the coils 105 in opposite directions about the objective lens 1, directions of the force respectively received by the coils 105 coincide with each other and the objective lens 1 is driven in the focussing direction F by a prescribed distance. Moreover, since electric currents are made to flow through coils for track 106 in opposite directions about the lens 1 when the coils 106 are conducted, directions of the force received by the coils 106 coincide with each other and the lens 1 is driven in the track direction by a prescribed distance. After winding the coil for focussing 105 and coil for track 106 around each bobbin 104, with the coils intersecting each other at almost right angles, two bobbins 104 are fixed to an objective lens holder 101.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an objective lens driving device used in an optical information recording device that writes information on an optical disk or an optical information reproducing device that reads information recorded on an optical disk.

An optical information recording device writes information by irradiating an optical disk with a laser beam focused by an objective lens, and an optical information reproducing device writes information by irradiating the optical disk with a laser beam focused by an objective lens. Although it is different from the information recording device described above in this respect, it is also a device that irradiates an optical disk with a laser beam focused by an objective lens and reads information recorded on the disk from the reflected light. The objective lens used in these optical information recording devices or reproducing devices can move in the focus direction, that is, the optical axis direction, and in the track direction, that is, the radial direction of the disk, in order to accurately write or read information. Therefore, the objective lens driving device must be of a two-dimensional type capable of focusing control and tracking control.

An example of a conventional two-dimensional drive type objective lens drive device will be described below with reference to the drawings.

3 to 5 show a conventional example, where FIG. 3 is a side sectional view, FIG. 4 is a plan view, and FIG. 5 is a perspective view showing the fixed state of the focusing coil and the tracking coil. be.

The objective lens 1 is fitted into and fixed to an objective lens support frame 2, and the objective lens support frame 2 is fixed to an intermediate member 4 to which a balance weight 3 is fixed. A plate spring 5 is attached to the intermediate member 4.
The plate spring 5 is fixed to the main body 8 integrally with the plate spring 7 via the relay member 6. A focusing coil 9 is wound around the outer periphery of the objective lens support frame 2, and on the outside thereof, a tracking coil 10 is divided into four groups and arranged at the corners of the objective lens support frame 2. . The track fill 10 is formed by gaps lla and ll in two magnetic circuits facing each other with the objective lens l in between.
b, and are wired so that current flows in the same direction within the same gap, and the track coil 10 interposed in the gap lla and the track coil 10 interposed in the gap lla.
It is wired so that a current flows in the opposite direction to that of the track coil 10 interposed in b. The two magnetic circuits each include a U-shaped yoke 12 and a magnet 13, and are magnetized so that the objective lens l side has the same polarity (in FIGS. 3 and 4, the objective lens 1 (the N pole side) is fixed to the main body 8.

In the above configuration, when a current is passed through the focusing coil 9, the directions of the currents across the gaps lla and llb are opposite, respectively, but the directions of the currents across the gaps lla and llb are opposite.

Since the directions of the magnetic flux lines generated in 11b are both directed toward the objective lens l side, the focusing coil 9 receives a force in the focus direction F, and the objective lens l moves in the focus direction F.

Furthermore, when a current is passed through the tracking coil 10, the current flows in the same direction within the same gap, so the tracking coil 1O receives a force in the track direction T, and the objective lens l moves in the track direction T. .

However, in the above conventional example, as shown in FIG. 5, it is necessary to firmly fix the focusing coil 9 and the tracking coil 10 to each other.

The four coils were required to be bent approximately 90".

The coil is easily disconnected and productivity is poor. In addition, when the focusing coil 9 and the tracking coil 10 are fixed, gaps lla and l are provided so as not to contact the magnet 13.
There is a problem in that the coil must be arranged within lb, there are restrictions on the number of turns of the coil and the gap distance, and assembly accuracy is also required.

Eyes Yesterday The present invention has been made in view of the above points.

A compact and highly productive objective lens drive for optical information recording or reproducing equipment, in which the focusing coil and tracking coil can be easily wound, and the gap distance between the magnet and the magnet can be easily and reliably adjusted. The purpose is to provide equipment.

Onstream 9-rattan bottom The present invention will be described in detail below based on the drawings.

FIG. 1 is a perspective view of one embodiment of the present invention, and FIG. 2 is a side sectional view of the main part of FIG.

The objective lens l is fitted and fixed into an objective lens holder 101, and the objective lens holder 101 has eight elastic members 102.
It is installed in the main body 103 so as to be movable in the focus direction F and the track direction T via. Further, a focusing coil 105 and a tracking coil 106 are wound around the bobbin 104 in directions substantially orthogonal to each other.
The two bobbins 104 are for focusing 05 and 1-
The rack coils 106 are wound and fixed to objective lens holders lots symmetrically with respect to the objective lens 1, respectively. Further, a yoke 108 to which a magnet 7 is fixed is disposed on the outside of each coil wound around the two bobbins 104, and one end of the yoke 108 is fixed to the main body 103. The two magnets 107 are magnetized so that the objective lens l side has the same polarity, and the two focusing coils +05 sandwich the objective lens l on the surface facing the magnet 107 so that currents in opposite directions flow therethrough. Further, the two track coils 106 are also wound so that currents in opposite directions flow between the objective lens l on the surface facing the magnet 107. In addition, the magnet 107 and the coil 105
, 106 are installed so that the gap distances between them are approximately equal on both the left and right sides.

The operation of the objective lens driving device according to the present invention configured as described above will be explained.

First, in operation, when the focusing coil 105 is energized, the two magnets 107 are installed so that the objective lens 1 side has the same pole (north pole in the figure). Since the current flows in opposite directions, the directions of the forces received by the two focusing coils 105 are the same, and the two focusing coils 105 are driven by a predetermined amount in the focusing direction F. Also, when the track coil 106 is energized, the current flows in the opposite direction between the two track coils 106 and 1, sandwiching the objective lens l.
The directions of the forces that 06 receives coincide with each other, and they are driven by a predetermined amount in the track direction T.

Note that the mark drawn on the cross section of the focusing coil 105 shown in FIG. 2 indicates the direction of the current flowing perpendicularly to the paper surface and on the opposite side, and the mark "■" indicates the direction of the current flowing perpendicular to the paper surface and on the near side. ing.

As is clear from the above operation description, the objective lens (■) is connected to the focusing coil +05 or the tracking coil 106
Coil +05 or +10(
i is driven by receiving force from the magnet 107.

In order to smoothly drive the objective lens 1, two focusing coils 105 and two tracking coils 105 and 105° are required.
It is necessary to wrap the objective lens 1 in opposite directions with the surfaces facing the magnet 107 so that the current flows, but as in this embodiment, the focusing coil 105 and the trunk coil +06 are If the coils 105 and 106 are wound on the two bobbins 104 so as to be substantially orthogonal to each other, and then the two bobbins 104 are fixed to the objective lens holder 101, the coils 105 and 106 can be easily wound with almost no risk of wire breakage during manufacturing. is completed, magnet +07 and focusing coil 105
．． Any gap distance of the trunk coil 106 can be easily adjusted.

Effects - As described above, according to the present invention, the focusing coil and the tracking coil are wound approximately orthogonally to the bobbin and then fixed to the objective lens holder, so that there is little risk of the coils breaking and it is easy to do so. It can be wound, and the gap distance to the magnet can be adjusted easily and reliably.
Not only can manufacturing steps be reduced to greatly improve productivity, but also a compact and highly accurate objective lens driving device can be achieved5.

[Brief Description of the Drawings] Fig. 1 is a perspective view of an embodiment according to the present invention, Fig. 2 is a side sectional view of the same main part, Fig. 3 is a side sectional view of the conventional example, and Fig. 4 is the same plane. FIG. 5 is a perspective view showing a conventional focusing coil and trunk coil fixedly attached to each other. l...Objective lens 101...Objective lens holder +03...Body +04...Bobbin 105
...Focusing coil 106 Track coil 107-Magnet 108...Yoke Patent applicant Asahi Optical Co., Ltd. Representative Matsumoto Withdrawal

Claims (1)

[Claims] an objective lens holder which is installed movably in the focusing direction and the tracking direction with respect to the main body, and into which an objective lens is fitted and fixed, and a focusing coil and a tracking coil which are fixed to both ends of the objective lens holder with the objective lens in between. two bobbins wound so that they are substantially perpendicular;
An objective lens drive device for an optical information recording/reproducing device, comprising two magnets facing the bobbin at a substantially equal distance and fixed to the main body via a yoke.