JPH03203040A - Optical recording and reproducing head - Google Patents

Abstract

PURPOSE:To absorb and decrease the magnetic fields generated by the repulsion of magnets from each other by disposing magnets for tracking and focusing in such a manner that their adjacent poles on the side facing a recording disk vary successively. CONSTITUTION:This head is provided with a lens holder 8 for holding an objec tive lens, a pair of the magnets 3, 6 for focusing dividedly magnetized to two poles in a focusing direction, a pair of the magnets 2, 4, 5, 7 for tracking dividedly magnetized to two poles in a tracking direction, a pair of focus flattening coils 10, 12 for focus driving attached to the lens holder 8, and a pair of tracking flattening coils 11, 13. The magnets 2 to 6 are so disposed that the adjacent poles on the side (arrow Z1 side) facing the recording disk vary successively like S, N, S, N, S and, therefore, the magnets 3 to 6 near the objective lens 9 attract to each other and the increasing of the leakage of the magnetic field in the Z direction as shown by magnetic lines R1, R2 of force is obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical recording/reproducing head for reproducing or recording information from a magneto-optical recording disk, and particularly relates to an objective lens driven by a magnet and a coil. This invention relates to improvements in drive mechanisms.

2. Description of the Related Art In recent years, recording disks called magneto-optical disks, which are used as storage media for computers, have come into widespread use. When writing or erasing information on a magneto-optical disk, it is necessary to expose the recording medium to a magnetic field with a magnetic field strength above a certain level perpendicular to the surface of the medium. Furthermore, the polarity must be reversed during writing and erasing. Therefore, a magnetic field generating means using an electromagnet or the like is generally provided. On the other hand, the driving means for driving the objective lens for applying laser light onto the recording medium is a so-called voice coil drive, and usually uses a strong permanent magnet.

3 to 5 are explanatory diagrams of main parts of a conventional optical recording/reproducing head. Figure 3 is a plan view of the objective lens drive mechanism.
4. FIGS. 1 and 5 are perspective views of essential parts. In the figure, reference numeral 1 denotes a base made of a magnetic material, on which a bottle 14 is erected as shown in FIG. This pin 14 engages with a cylindrical sleeve 17 attached to the lens holder 8, and the lens holder 8 rotates in the direction of arrow A in FIG.
It is supported so that it can slide in the direction. An optical bench 18 is attached to the lower part of the base 1 so that a laser beam is guided to an objective lens 9 through a through hole 1e provided in the rear base 1. Base 1 pz is the number of magnets 1)
-) Recesses 1a, Ib, 1c and 1d are provided, and magnets 2.3.4.5.6, 15.16 are attached to each. The polarities of the magnets are arranged as shown in FIGS. 3 and 4 with emphasis on symmetry. 10 and 12 are lens holders 8 facing magnets 3.16 and 6.16.
V? : is an attached flattened coil for driving in the focus direction, and 11.13 is a flattened coil for driving in the tracking direction. By applying A current to each flat coil, the 6th m"=4 in the focus direction
In the direction of arrow B, that is, the tracking direction, the lens holder 8 is driven in eight directions of arrow A, and as a result, the objective lens is driven.

Problem to be Solved by the Invention However, in the conventional configuration as described above, for example, the magnets 5 and 6 are adjacent to each other, and moreover, the Ni comrades face each other near the objective lens. The lines of magnetic force repel each other and generate a relatively large two-directional magnetic field near the objective lens (arrow M in FIG. 4). Since the magnet 6.6 is a permanent magnet, this bidirectional magnetic field is fixed. Therefore, when trying to generate a magnetic field in the direction perpendicular to the medium surface using an electromagnet, etc. as described above, the magnetic field strength will be added if the direction is the same as the magnetic field generated by the magnet 6.6, and subtracted if it is opposite. That will happen. In general, the magnetic field strength required for recording and reproducing on a magneto-optical disk does not differ much between reproduction and erasing. For this reason, the existence of a fixed magnetic field is undesirable. 1 & To drive the lens holder, a strong magnet is required to improve performance. Therefore, there is a problem in that it is necessary to reduce the amount of magnet leaking from the magnet for driving the lens holder without impairing the performance of the driving mechanism. In view of the above-mentioned problems, it is an object of the present invention to provide an optical recording/reproducing head that can minimize the leakage of magnetic force even if a strong magnet is used to drive the lens holder. purpose.

Means for Solving the Problems In order to achieve this object, the present invention provides an optical recording/reproducing head for recording and reproducing information on a recording disk.
A lens holder that holds an objective lens, a pair of focus magnets that are magnetized into two poles in the focus direction,
A pair of tracking magnets magnetized with 2 poles + r e in the tracking direction, -24 no-orcus flattened coil for focus drive attached to the lens holder facing the NME focus magnet, and the tracking magnet. A pair of flat tracking coils for tracking drive are attached to the lens holder facing the magnet, and the poles on the side facing the recording disk are arranged so that adjacent poles are arranged differently. .

A41: By the above-described structure, the present invention can absorb and reduce leakage of magnetic fields generated by repulsion between magnets.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

Referring to FIG. 1, the arrangement buttons and functions of each component are the same as in the conventional example. However, only the arrangement of the magnet poles is different. In other words, in the conventional example, the arrangement focused on symmetry, but in this example, as can be seen from FIG.
, S , N , S, the side facing the recording disk,
First, adjacent poles on the side of the arrow Z in FIG. 2 are arranged so as to be different in order. Because of this arrangement, the magnets 3, 4, 6, 6 near the objective lens 9 are attracted to each other as shown in Figure 2.) They are attracted to the adjacent magnets as shown by the magnetic lines of force R1 and R2, which is different from the conventional example. The leakage of the magnetic field does not become thicker in two directions. It is natural to match the polarity of the flat coil in response to changing the arrangement of the magnet poles in accordance with the above embodiment.

In this example, each magnet is divided into two parts.
For example, 8 magnets are used.
An embodiment using a two-pole magnetized magnet in which the magnets 2 and 7 are integrally molded and only the magnetization is performed as shown in FIG. 1 is easily conceivable. Naturally, the present invention is also applicable to cases where it is used only for reproduction.

Effects of the Invention As is clear from the description of the embodiments above, the present invention provides an optical recording and reproducing head for recording and reproducing information on a recording disk, which includes a lens holder for holding an objective lens, and a lens holder for holding an objective lens, a pair of focus magnets that are magnetized in two poles; a pair of tracking magnets that are magnetized in two poles in the tracking direction; and a focus drive magnet that is attached to the lens holder facing the focus magnet. and a pair of tracking flat coils for tracking drive attached to the lens holder facing the tracking magnet, and an array of poles on the side facing the recording disk. are arranged so that adjacent poles are different from each other.
It has a simple configuration, and can effectively prevent magnetic field leakage, and has great practical effects.

[Brief explanation of drawings]

FIG. 1 is a plan view of an optical recording/reproducing head according to an embodiment of the present invention, FIG. 2 is a perspective view of essential parts of the same embodiment, FIG. 3 is a plan view of a conventional example, and FIGS. 4 and 5 is a perspective view of the same essential parts. 2.4,5. Completed...Tracking magnet, 3゜6.15.16...Focusing magnet, 8...
・Lens holder, 9...Objective lens, 10.
12...Flat coil for focusing, 11. 13...
・・・Flat coil for tiger and king, Zl ・・・・・・
The side facing the recording disk.

Claims (1)

[Claims] A lens holder that holds an objective lens, a pair of focus magnets that are magnetized into two poles in the focus direction,
a pair of tracking magnets divided into two poles magnetized in the tracking direction; a pair of focus flattened coils for focus drive attached to the lens holder facing the focus magnet; and the tracking magnet A pair of flat tracking coils for tracking drive are attached to the lens holder facing each other, and the two pairs of magnets are arranged such that adjacent poles of the two pairs of magnets are different from each other on the side facing the recording disk. optical recording/playback head.