JPS6260148A - Photomagnetic information recording and reproducing device - Google Patents

Abstract

PURPOSE:To ensure the stable working of a recording/reproducing device with no effects of the ambient temperature change, the disturbance and an external magnetic field, by detecting the relative position shift between a light beam and a magnetic head and controlling the relative position of them approximately to the fixed relation based on the detection signal of said relative position shift. CONSTITUTION:A magnetic head 4 contains a detecting means for relative position between a light beam and the head 4. A recording medium is set between a semiconductor laser 1 and the head 4 and moved. While a carriage 2 contains a permanent magnet 5 and a holding member 3 contains a coil 6. Thus a control means is obtained for control of the relative position between the light beam and the head 4. In such a constitution, the detection signal obtained corresponding to the position shift detected by said detecting means for relative position between the light beam and the head 4 energizes the control current to shift the member 3 to the coil 6. Thus the member 3 moves toward the shift direction (arrow head) of the recording medium by the magnetic force generated by the magnet 5 and the coil 6. Thus the relative position between the light beam and the head 4 can be kept at the fixed relation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application J The present invention relates to a magneto-optical information recording and reproducing device that records, reproduces or erases information based on the magneto-optical effect.

[Prior Art J FIGS. 6 and 7 show two typical examples of conventional magneto-optical information recording and reproducing devices. In FIG.
For example, a pulse mode light beam 103 modulated according to information is emitted from the DC core source 104.
A bias magnetic field in a fixed direction is applied by driving the magnet 105 to record and erase information on the magneto-optical disk lOO. A magneto-optical information recording and reproducing apparatus using such a light beam modulation method is also found in Japanese Patent Application Laid-Open No. 59-203258. On the other hand, FIG. 7 shows a magneto-optical information recording and reproducing apparatus using a magnetic field modulation method, an example of which can also be found in Japanese Patent Laid-Open No. 57-40761.

In FIG. 7, the magneto-optical disk lOO is a signal source 107.
A bias magnetic field modulated by
A continuous mode light beam 111 is irradiated from the semiconductor laser 102 driven by the magneto-optical disk 100, and information is recorded or erased on the magneto-optical disk 100.

FIG. 8 shows the temperature (
This is a temperature characteristic diagram showing changes due to T) for a so-called RE-TM type amorphous magnetic thin film having perpendicular magnetic anisotropy. According to FIG. 8, it can be seen that the holding force of the magnetic thin film of the magneto-optical disk decreases as the temperature rises.

Figure 59 shows the distance #(x) from the center of the light beam and the magnetic F! when a light beam from a semiconductor laser or the like is focused through an objective lens and irradiated onto the magnetic thin film of the magneto-optical disk L. FIG. 3 is a diagram showing the relationship with the coercive force (Hc) of the film. According to FIG. 9, the magneto-optical disk has magnetic F! It can be seen that the coercive force of the film increases rapidly as it moves away from the center of the light beam.

Figure 1O shows six direct magnetic field components (H
FIG. 3 is a diagram showing how the distance changes depending on the distance (y) between the magnetic thin film of the magneto-optical disk and the gap between the magnetic head. According to FIG. 10, it can be seen that as the magnetic thin film of the magneto-optical disk moves away from the gap of the magnetic head, the effective perpendicular magnetic field component (Hy) decreases slightly.

Now, it is generally known that the magnetization direction of the magnetic thin film is determined at the point where the magnetic Pj film moves relative to the magnetic head and the magnetic field from the magnetic herad becomes weaker than the coercive force of the magnetic thin film.

By the way, conventionally, the magneto-optical information recording and reproducing apparatus has the 11th
It is constructed as shown in the figure. That is, a semiconductor laser 102 and a magnetic herad 113 irradiate the magneto-optical disk lOO with a light beam 112 and apply a bias magnetic field.
is integrally attached to a carriage 114, and the carriage 114 has a drive shaft 11 rotated by a drive source 115.
6 in a direction across the tracks (not shown) of the magneto-optical disk 100. Note that, generally, the light beam 1
12 to irradiate the magneto-optical disk 100 with focus control, and to direct the light beam 112 to the magneto-optical disk lOO.
It has an objective lens moving mechanism (not shown) for tracking along the track.

[Problems to be Solved by the Invention] As mentioned above, the magnetic thin film of a magneto-optical disk has a coercive force that has a temperature characteristic (Fig. 8), and the coercive force varies depending on the distance from the center of the irradiated light beam. In addition, the effective perpendicular magnetic field component to the magnetic thin film also depends on the head gap and magnetic field (Figure 9). 1ilW2 (Fig. 10).In contrast, according to the prior art, the magnetic head and semiconductor laser of a magneto-optical information recording/reproducing device are sandwiched between a magneto-optical disk as shown in Fig. 11. They are integrally attached to the carriage at a distance from each other, and the relative positional relationship between the magnetic head and the conductor laser may shift due to expansion/contraction displacement, distortion, or external vibration due to changes in ambient temperature, for example. . As a result, the perpendicular magnetic field generated by the magnetic head may not exceed the coercive force of the magnetic thin film of the magneto-optical disk, or the bias magnetic field may be swayed by an external magnetic field, making it difficult to record or erase information on the magneto-optical disk. The present invention has been made to solve the problem of the prior art, and is capable of detecting errors without being affected by changes in ambient temperature, external vibrations, or external magnetic fields. It is an object of the present invention to provide a magneto-optical information recording/reproducing device having excellent reliability and operational stability.

[Means and Effects for Solving the Problems 1] In order to achieve the above-mentioned object, the present invention provides a magneto-optical information recording/reproducing apparatus in which a light beam and a magnetic field applying means for applying a magnetic field to a magneto-optical information recording medium are connected to each other. A magneto-optical information recording and reproducing apparatus is configured by providing means for detecting a relative positional relationship between the light beam and the magnetic field applying means, and comprising means for adjusting the relative positional relationship based on the detection signal, The adjusting means acts to maintain the relative positional relationship substantially constant based on the detected detection signal, thereby realizing a stable and highly reliable magneto-optical information recording/producing device.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. In the following description of the drawings, the same elements having the same function are given the same reference numerals to avoid duplication of description.

FIG. 1 is a schematic diagram showing an embodiment of a magneto-optical information recording and reproducing device related to unreleased IJI, and the magneto-optical information recording medium (description is omitted, hereinafter referred to as recording medium) is indicated by the arrow in the figure. move in the direction. That is, in the case of a recording medium having a track structure, it is the track direction. A semiconductor laser 1 that irradiates a recording medium with a light beam is attached to a carriage 2,
Further, in the carriage 2, a magnetic heald 4 that applies a magnetic field to the recording medium via the holding member 3 is installed in the moving direction of the recording medium (
It is placed in a moat that can be moved in the direction of the arrow in the figure.

The magnetic head 4 is equipped with means for detecting the relative position between the light beam and the magnetic head, which will be described later.

A recording medium (not shown) includes a semiconductor laser 1 and a magnetic helad 4.
It is placed between and moves. On the other hand, a permanent magnet 5 is attached to the carriage 2, and a coil 6 is attached to the holding member.
are attached to form four stages for adjusting the relative positional relationship between the light beam and the magnetic head. Furthermore, carriage 2 is
According to this embodiment, the magnetic helad 4 is movable in a direction transverse to the moving direction of the recording medium (direction perpendicular to the arrow in the figure) by a drive shaft 8 rotated by a drive source 7. The detection signal 1) corresponding to the positional deviation detected by the relative position detection means (described later) between the optical beam and the magnetic head, which is included in the
A control current for moving and displacing the holding member 3 is passed through the coil 6, and as a result, the holding member 3 is moved in the direction of movement of the recording medium (arrow direction in the figure) due to the magnetic force between the permanent magnet 5 and the coil 6, and the relative positional relationship is changed. The drive source 7 rotates the drive shaft 8 to move the entire carriage 2 in a direction perpendicular to the direction of movement of the recording medium, and directs the light beam and magnetic field to the location of the recording medium ψ. It acts to apply irradiation to the position of.

FIG. 2 shows a first specific example of the magnetic herad 4 shown in FIG. -9 is incorporated, and a light beam 91 is transmitted through a recording medium (not shown).
irradiates the light receiving section 92, and generates a detection signal at the output terminal 93 according to the relative position between the earpiece 41 of the magnetic head 4 and the light beam 91. In addition, in the figure, 42 is ten magnetic poles, and 43 is one magnetic pole. Further, arrows in the figure indicate the moving direction of the recording medium, and 44 indicates a coil for generating a bias magnetic field.

FIG. 3 is a diagram showing the relative positional relationship (Z) between the light beam and the gap of the magnetic head and the relationship between the detection output (V) of the photoelectric conversion element 9 in the example E. It can be seen that by relatively varying the positions of the optical beam and the magnetic field, for example from position W10 to position 'IIZ1, the output becomes El, and a large change occurs in the signal output.

FIG. 4 shows a second specific example of the magnetic head shown in FIG. According to the 0-wire specific example in which a detection signal proportional to the area irradiated by the beam (light-receiving area) is obtained at the output terminal 93, it is easier to manufacture than the first specific example, and the light-receiving part 92 is less contaminated. It has characteristics that make it easy to prevent such problems.

FIG. 5 shows that the first
FIG. 6 is a block diagram showing an example of a control system that operates the coil 6 and maintains the relative positional relationship between the light beam and the magnetic head substantially constant. Photoelectric conversion element 9 included in the magnetic head
According to the zero control system, the output of the reference level generator 10 and the output of the reference level generator 10 are inputted to the comparator 11, and the comparison output is supplied via the driver 12 to the coil 6 that moves the holding member 3 shown in FIG. The reference level generator 10 inputs, for example, an output corresponding to El in FIG. The relative position will be adjusted. That is, the output of the reference level generator 10 is:
The level may be set by adjusting the output to the minimum error rate during recording and reproducing by the magneto-optical information recording and reproducing device.

In the above description, the recording medium may be disk-shaped, tape-shaped, or other shapes, and the bias magnetic field generation F
Of course, the stages can also be made of permanent magnets. Further, the means for moving the magnetic head in the direction in which the recording medium moves or in the direction orthogonal to the direction is not limited to the one described above, and may be any other normally available one stage. Although an example has been described in which the two are attached to a common carriage, they may each be moved using separate drive sources. Although the width of the light beam is shown in the figure, a plurality of light beams may be used without changing the effect of the present invention.

(Effect of the invention 1 Thu: 5?! ilI, in a magneto-optical information recording and reproducing device, the relative positional deviation between the light beam and the magnetic head is detected, and the light beam and the magnetic head are adjusted based on the detection signal. Since the relative positional relationship between the two is adjusted and maintained at a substantially constant level, errors in recording or erasing information are prevented without being affected by ambient temperature changes, disturbances, or external magnetic fields, improving reliability and operational stability. An excellent magneto-optical information recording rIf generation device can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a magneto-optical information recording and reproducing apparatus showing one embodiment of the present invention, FIG. 2 is a configuration diagram showing a first specific example of a magnetic head according to the present invention, and FIG. A diagram showing the output of a detection signal according to the relative positional deviation between the magnetic head and the light beam, FIG. 4 is a configuration diagram showing a second specific example of the magnetic head according to the present invention, and FIG. A block diagram showing an example of a control system for adjusting the relative forward position of the magnetic head and the magnetic head.
6 and 7 are explanatory diagrams of the prior art, and FIG. 8 is a temperature characteristic diagram showing changes in the holding force of the magneto-optical disk due to temperature.
Figure 9 is a diagram showing the relationship between the distance from the center of the light beam and the coercive force of the magnetic thin film, Figure 10 is a diagram showing the change in the perpendicular magnetic field component depending on the distance between the magnetic thin film and the gap between the magnetic head, and Figure 11. is an explanatory diagram of the prior art. L...Patoconductor laser 2...Carriage 3...Holding member 4...Magnetic head 5...Permanent magnet 6...Coil 7...Drive source 8...Drive shaft 9... Photoelectric conversion element 10... Reference level generator 11... Comparator 12... Driver 41... Gap 91... Light beam 92... Light receiving section Patent applicant Olympus Optical Industry Co., Ltd. 6, coil 7. Drive source 8 Drive shaft Fig. 6 Fig. 9 Fig. 10 c Fig. 11

Claims (1)

[Claims] (1) Irradiating the magneto-optical information recording medium with a light beam, and/or
Alternatively, in a magneto-optical information recording and reproducing apparatus that records, reproduces, or erases information by applying a magnetic field, a means for detecting a relative positional relationship between the light beam and the means for applying the magnetic field is provided; It is characterized by comprising means for adjusting the relative positional relationship based on the detection signal of the detection means, so that the relative positional relationship between the light beam and the magnetic field applying means is maintained substantially constant. Magneto-optical information recording and reproducing device.