JPS62125554A - Magneto-optical head - Google Patents

Abstract

PURPOSE:To attain a compact and light-weight magneto-optical head and to prevent the electromagnetic adverse influence given to the drive mechanism of an objective lens from the head, by forming an electromagnet by covering the inner and outer circumferential areas of a coil with a magnetic barrel. CONSTITUTION:A current is supplied to a coil 14 to generate a magnetic field strong enough to invert the magnetization of a recording medium 8 in a record/ erasion mode. Here the coil 14 is covered with barrels 13 and 15 made of a magnetic substance and the side opposite to the medium 8 is also covered with a coupling member 16. Thus the leaked magnetic fluxes are reduced and no adverse influence is given to an optical head 10. Furthermore both barrels 13 and 15 are formed centering on an objective lens 9 of the head 10. While an electromagnet 12 has a symmetrical structure to a concentric center of the lens 9. Thus the magnetic field has only the vertical component at the area of the medium 8 where the beam is irradiated. Then the direction of magnetization is easily stabilized in the vertical direction. Thus a vertical magnetic field is generated effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magneto-optical head that can be used in all storage devices that do not require high-speed access, such as image memories and external storage devices for computers.

2. Description of the Related Art An example of a conventional device of this type will be described with reference to FIG. First, an optical head 3 equipped with an objective lens 2 is provided facing one surface of a disk-shaped recording medium 1, and an electromagnet 6 consisting of a core 4 and a coil 5 is provided facing the other surface of the recording medium 1. The electromagnet 6 and the optical head 3 are connected and integrated by a connecting portion 7 so that both can be moved without changing their relative positions. Recording and erasing is performed by generating an external magnetic field sufficient to reverse the magnetization of the recording medium 1 using the electromagnet 6, and by irradiating a high-power electromagnetic wave beam from the optical head 3. Furthermore, reproduction is performed by irradiating a linearly polarized electromagnetic wave beam with a lower output than that used during recording and erasing, and detecting the polarization state of the reflected or transmitted electromagnetic wave beam.

Problems to be Solved by the Invention Since the optical head 3 and the electromagnet 6 are arranged with the recording medium 1 in between, the overall shape of the integrated unit at the connecting part 7 is large, and moreover, the parts are moved. Therefore, there is a problem that the space occupied by the optical head 3 must be increased. Also, for this reason, recording medium 1
It is also difficult to manage the space in which it must be placed.

Furthermore, in the optical head 3, the objective lens 2 is moved using an electromagnetic device, but the external magnetic field generated by the electromagnet 6 may have an adverse effect on the mechanism that drives the objective lens 2. It is.

Means for Solving the Problem] An electromagnet is formed by covering the inner and outer peripheries of the cylinder with a cylinder made of magnetic material, and an optical head is disposed at the inner periphery of the electromagnet.

Since the working optical head and the electromagnet are located only on one side of the magnetic recording medium, it is only necessary to provide a space for moving them on one side of the recording medium, which simplifies the design of the entire device. Since its inner and outer circumferences are covered with a cylinder made of magnetic material, it does not adversely affect the movable groove of the objective lens S of the optical head.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 and 2. First, the objective lens 9 is placed opposite to one surface of the recording medium 8.
An optical head 10 having an optical head 10 is connected to a drive mechanism (not shown). An electromagnet 12 is attached to the outer periphery of the optical head 10 via an attachment member 1 made of a non-magnetic material. This electromagnet 12 consists of a cylinder 13 made of a magnetic material that is joined to the mounting member 11, a coil 14 wound around this cylinder 13, and a cylinder 15 made of a magnetic material that covers the outer periphery of this coil 14. The end opposite to the recording medium 8 at 15° is connected to a coupling member 1 made of a magnetic material.
6.

The cylinder 13.15 of the electromagnet 12 is formed in a cylindrical shape with the objective lens 9 of the optical head 10 at its center.

In such a configuration, the recording medium 8 is used during recording and erasing.
A current is passed through the coil 14 such that a magnetic field sufficient to reverse the magnetization of the coil 14 is generated. At this time, the coil 14 is covered with a magnetic cylinder 13.15, and the side opposite to the recording medium 8 is also covered with a magnetic coupling member 16, so the leakage magnetic flux is small and the optical head 1o is have no negative impact on.

Further, the cylinder 13.15 is connected to the objective lens 9 of the optical head 10.
Since the electromagnet 12 has a symmetrical structure with respect to the center of the concentric circles, the magnetic field in the portion of the recording medium 8 irradiated with the beam has only a vertical component, and the direction of magnetization is in the vertical direction. It is easy to stabilize and has high efficiency in generating vertical magnetic fields.

Effects of the Invention The present invention forms an electromagnet in which cylinders made of magnetic material are arranged on the inner and outer peripheries of the coil as described above, and stores part or all of the optical head in the inner periphery of this electromagnet. Recording/erasing is performed by irradiating the recording medium with a high-power electromagnetic wave beam in a perpendicular magnetic field, and the polarization state of the electromagnetic wave beam that is reflected or transmitted by irradiating the recording medium with a linearly polarized electromagnetic wave beam of lower power than during recording/erasing. When detecting and reproducing data, there is little leakage magnetic flux, there is no electromagnetic adverse effect on the drive mechanism of the objective lens of the optical head, and the optical head and electromagnet are arranged on one side of the recording medium. Therefore, it has advantages such as being able to be made small and lightweight.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional side view thereof, and FIG. 3 is a side view showing an example of the conventional technology. 8...Recording medium, 9...Objective lens, 10...Optical head, 12...Electromagnet, 13...Cylinder, 14...
Coil, 15, cylinder, 16... coupling member

Claims (1)

[Claims] 1. Recording and erasing is performed by irradiating a recording medium with a high-power electromagnetic wave beam in a perpendicular magnetic field, and irradiating and reflecting a linearly polarized electromagnetic wave beam with a lower power than that used during recording and erasing. Alternatively, in a magneto-optical storage device that detects and reproduces the polarization state of a transmitted electromagnetic wave beam, an electromagnet is formed with cylinders made of magnetic material arranged on the inner and outer peripheries of a coil, and an optical head is placed on the inner periphery of this electromagnet. A magneto-optical head, characterized in that a part or all of the head is accommodated. 2. The magnetism according to claim 1, characterized in that part or all of the ends of cylinders arranged on the inner and outer peripheries of the coil on the side opposite to the recording medium are connected by a magnetic material. optical head. 3. The magneto-optical head according to claim 1, wherein the two cylinders of the electromagnet are formed in a cylindrical shape centered near the objective lens of the optical head.