JPS5911557A - Magnetooptic reproducer - Google Patents

Abstract

PURPOSE:To transmit easily the stable polarized light in a polarized plane to a magnetooptic member, by providing incorporatedly an optical member changed with the amount of transmitted light in response to the plarized plane of light at both sides of the magnetooptic member for suppressing the mechanical vibration to a small value. CONSTITUTION:The reproducing head 11 is provided incorporatedly with the 1st and the 2nd optical members 16, 17 whose amount of transmitted light is changed in response to the polarized plane of light at both sides of the magnetooptic member 15 forming the magnetic material into thin film by means of a means such as bonding. A light beam 13 irradiated from a light source 12 is led to the 1st optical member 16 via a lens mount 20a, converted into a linearly polarized light having a polarized plane in a direction at the optical member 16 and enters the magnetooptic member 15. The magnetooptic member 15 is magnetized according to a magnetic recording signal according to the magnetic recording signal of a magnetic recording medium 14 in this case, and the polarized plane of the linearly polarized light is rotated with the magnetooptic effect such as the Farady effect or the Cotton-Mouton effect or the like. The amount of transmitted light changes according to the rotation of the polarized plane with the 1st optical member 17 in the linearly polarized light receiving the magnetooptic effect and the result is led to a photodetector 18 as an output light beam 19 via a lens mount 20b, the signal is converted into an electric signal, and the magnetic recording signal on the magnetic recording medium is reproduced.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a conventional magneto-optical reproducing apparatus a as described above, which reads out recorded information on a magnetic recording medium by using a magneto-optic effect such as the Faraday effect. Various things are thought of as t1.

One method is to use a material with a magneto-A optical effect in the recording medium itself, irradiate the surface of the medium with IM) light, and use the Faraday effect or Kerr effect to
No. 14 is directly read out.

The recording medium used here has the characteristics necessary for magneto-optics, which are far beyond its original characteristics as a recording medium.

For example, the sieve Faraday rotation angle characteristics must also be thoroughly determined, but it is extremely difficult to produce such a high-performance recording medium.

If a laser is used and a high-performance optical system is used, the diameter of the focused light beam is jl (about microns, so
High-density recorded signals cannot be reproduced satisfactorily.

Second, a magnetization transfer film is arranged so as to be in sliding contact with the plate surface of the recording medium. There is a device that reads recorded signals by exposing the rotation of the plane of polarization (Kerr effect) that is proportional to the change in polarization.

Here, the recording medium does not need to have magneto-optical properties, and it is sufficient that the magnetization transfer film has magnetization transferability and magneto-optical properties.

Similarly to the above, this device 4 also has a spatial resolution of the same size as the light beam used during reproduction.

It is difficult to reproduce high-density recorded signals.

Thirdly, in order to improve the problem of reproduction resolution that is common to each of the above-mentioned devices, as shown in FIG. A high magnetic permeability magnetic layer 1 is vertically placed on the holder 3, and the recording 1 of the ice A recording medium 4 is
No. g is transferred to 1 (Yoshika transfer film 1).

There is a device that irradiates the magnetization transfer film 1 with Raded light and reads out the magnetization signal recorded on the magnetization transfer film 1 by utilizing the Kerr seedling or Faraday effect.

Here, 5 is a light emitting light, and 6 is a light beam.

7 is Half Mirror, 18 is Lens, 9 is Kuko Jutora, 10
is a photodetector.

However, it is technically difficult to provide the high permeability magnetic thin film 2 perpendicularly to the overlapping transfer film 1! lr+1 Unfortunately, such a complicated M4IIM is not suitable for large-scale production.

In addition, since the photon 6, analyzer 9, and magnetic transfer 1[@1 are each arranged independently, they are susceptible to mechanical vibrations, increasing detection accuracy, and achieving high efficiency and miniaturization. This will put you at a disadvantage.

[Purpose of the invention]

This invention was made in order to solve 186 problems, and it is possible to simplify the structure, to be unaffected by mechanical vibration, and to record high-density recording signals with high resolution and high efficiency. It is an object of the present invention to provide a magneto-optical reproducing device i that can perform reproduction.

[Summary of the invention]

In this invention, first and second optical members that change the intensity of transmitted light depending on the plane of polarization of light are integrally provided on both sides of a magneto-optical member made of a thin film of magnetic material, and the tip of the magneto-optical member is connected to a magnetic recording medium. The beam is transmitted through the magneto-optical member and the first and second optical parts by disposing them in contact with or in close proximity to each other. It is something to be regenerated.

〔Effect of the invention〕

This invention is achieved by integrally providing optical members on both sides of a magneto-optical member that change the transmitted light depending on the polarization plane of the light.
It is an optical material that can receive extremely small mechanical vibrations, can easily transmit stable light control on the optical surface to the magneto-optical member, and is inexpensive enough to make the optical system absorb light. You can subtract 1 color with this. Moreover, the magneto-optical section H
Spatial resolution tr by setting the thickness and width of ゛ small.
7) It has the advantage that it is possible to play back Jfn files with high recording density by directing the 14.

[Confirmation of the Invention] One embodiment of the present invention will be explained below with reference to one drawing.

tm21ffll where 11 is light r),'i 12
, a reproducing head disposed perpendicular to the upper nine beams 13, and the head 11a of this head 11 is brought into contact with the hc recording surface of the magnetic recording medium 14. This regeneration henol'l
1 is a magneto-optical member 15 formed of a thin film of magnetic material;
Both sides of the optical member 16 and 17 are arranged in 11 pieces using means such as a contact 7#. In the illustrated case, a first optical member 16 is integrally provided on one surface of the magneto-optical member 15 as a thin film-like polarizing optical member that converts the incident beam 13 into linearly polarized light, and on the other surface, The reproducing head 11 is integrally provided with a second optical member 17 in which the transmitted light I changes according to the rotation angle of the plane of polarization using the magneto-optic effect generated by the magnetic recording signal of the magnetic recording medium 14.

Here, 18 is a photodetector for detecting the output light beam 19 transmitted through the second optical member 17, and 20a is the incident light beam 13.
The output light beam 19 is guided through the heel body 20b, which is bent and guided perpendicularly to the side surface of the first optical member 14. light beam 1
3 is converted into linearly polarized light having a plane of polarization in one direction by the optical member 16, and then enters the magneto-optical member 15. At this time, the magneto-optical member 15 is magnetized according to the magnetic recording signal of the magnetic recording medium t4-14, and the plane of polarization of the linearly polarized light is rotated by a magneto-optical effect such as the Faraday effect or the Cotton-Mouton effect. The linearly polarized light subjected to this magneto-optic effect changes the transmitted light stitch by the W,1 optical member 17 according to the rotation of the polarization plane, and is guided as an output light beam 19 to the photodetector 4181 via the mirror body 20b. Here the output light beam 19 is converted into an electrical signal,
A magnetically recorded signal on a magnetic recording medium is reproduced.

Therefore, according to such a configuration? By forming the optical member 15 as a magnetic film that is sufficiently thin compared to the recording wavelength of the magnetic recording medium 14.

The reproduction resolution can be improved regardless of the diameter of the light beam 13, and this can be done with high efficiency, and is particularly effective in reproducing magnetic recording signals with extremely high recording density.

In addition, by irradiating the incident light beam 13 directly onto the magneto-optical member 15 from the side, the irradiation can be localized to the vicinity of the tip of the magnetic recording medium 14, which is located at a certain distance from the recording surface of the magnetic recording medium 14. Therefore, it is possible to prevent deterioration of the resolution due to the length of the magneto-optical member 15.

Furthermore, there is no possibility that the photon and analyzer setting angles will fluctuate due to the magnetic n41 z.

This method has the advantage that a mechanically stable magneto-optical device can be obtained, and the optical system can be made of an inexpensive optical material that can transmit light.

Next, FIG. 3 shows the mirror body 20a of the embodiment shown in FIG.

20b, the reproducing head 31 is constructed by integrally providing first and second solid light guides 31a and 31b on both sides of the first and second optical members 16 and 17.

The first and second solid light guides 31a, 31b have reflections i132a, 32b formed on their end faces. Here, parts that are the same as those in FIG. 2 are given the same numerals and their explanations are omitted.

Therefore, according to such a configuration, it is possible to achieve the same effects as described above, and in addition, by integrally providing the solid light guides 3ta and 3ib in the reproduction head 11, it is possible to easily reduce the size and stabilize the reproduction head 11. It can be measured.

Furthermore, FIGS. 4 and 5 are improvements on the embodiment shown in FIG. 3. FIG. 4 shows the first solid light guide 31a.
And the first optical department +! 16 and between the second solid light guide 31b and the second optical member 17, transparent holders 41a and 41b are inserted, respectively, to constitute the playback head 41.

A reproducing head 51 is constructed by inserting transparent holders 51a and 51b between the 1ζ magneto-optical member 15 and the optical member I7 of 2, respectively.

Here, the same parts as in FIG. 3 are marked with the same symbol -t=r, and the explanation thereof is omitted.

Therefore, according to such a configuration, the same effects as described above can be achieved. Moreover, the head of the playback head 41 or 51 is 1 m 42:+ or 52.・Contact rf
Since lit can be set large, it is possible to bring the reproduction spatula 1!41 or 51 into smooth contact with the magnetic recording medium 14, and it is also possible to improve durability and strength.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without changing the gist.

For example, in the embodiments of FIGS. 3 to 5, the solid light guide 3]
Although the reflective surfaces of a and 31b are formed into one flat surface to bend the light beam, the present invention is not limited to this.
The reflective surface can also be formed into a parabolic curved surface to focus the light beam onto a single point on the magneto-optic member to further improve resolution and efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing an example of a conventional magneto-optical reproducing device, FIGS. 2 and 3 are sectional views showing the schematic structure of an embodiment of the present invention, and FIGS. FIG. 5 is a schematic diagram of a modified example of the optical magnetic head used in the present invention. 1...Magnetic transfer film 2...Magnetic permeability magnetic 'U film 3
...Holder 4...Magnetic recording medium 5...
Light source 6...Polarizer 7...Half mirror
8...Lens 9...Analyzer 10...Photodetector 11...
Playback head lla...Head surface 12...Light source
13... Light beam 14... Magnetic recording medium 15... Magneto-optical member 16... First optical member 17... Second optical member 18... Photodetector
19... Output light beams 20a, 20b -tA body 31... Reproduction head 31a... First solid light guide 31b... Second solid light guide 32a, 32b
... Reflective surface 41.51... Playback head

Claims (5)

[Claims] (1) In a magneto-optical reproducing device in which the tip of a magneto-optic member is arranged in contact with or in close proximity to the surface of a magnetic recording medium and reads a recorded signal of the recording medium using the magneto-optic effect, the magneto-optic member A magnetic device characterized in that the member has first and second optical members integrally formed on both sides of the member, the amount of transmitted light changing depending on the polarization plane of the light, either directly or with another member interposed. Optical reproduction device. (2) First and second solid light guides each having an end face serving as a reflective surface at their tips are integrally provided on both sides of the first and second optical members. A magneto-optical reproducing device according to claim 1. (3) The magneto-optical reproducing device according to claim 2, characterized in that a transparent holder is interposed between the first and second optical members and the first and second solid light guides, respectively. . (4) The magneto-optical reproducing device according to claim 2, characterized in that a transparent holder is interposed between the magneto-optical member and the first and second optical members, respectively. (5) The end surfaces of the first and second solid-state optical conductors are configured to have a radial/south surface with a focal point near the tip of the magneto-optical member. 5. The magneto-optical reproducing device according to any one of Item 4.