JPH02292755A - Magneto-optical recorder - Google Patents

Abstract

PURPOSE:To accurately decide the length of a bit at the time of recording or erasing with respect to the length of a recording signal by temporally controlling the magnetic field modulating action of a magnetic head by a modulation time control means in accordance with the magnitude of leakage magnetic field which acts to a recording carrier from an actuator. CONSTITUTION:An objective lens 6 which is arranged in an optical path from a light source to the magneto-optical recording film of the recording carrier 1 and driven by the actuator 7 is arranged to be opposed to the magnetic head by putting the recording carrier 1 between them. Then, a magnetic field modulation means 10 for inverting a direction where the magnetic field of the magnetic head acts in accordance with the recording signal is provided and the modulation time control means 12 is connected to the means 10. Since the magnetic field modulating action of the magnetic head can be temporally controlled by the modulation time control means 12 in accordance with the magnitude of the leakage magnetic field impressed on the recording carrier 1 from the actuator 7, the length of the recording signal is made to coincide with the impressing time of the magnetic field for recording or erasing, which is impressed on the recording carrier 1 from the magnetic head. Thus, the length of the bit at the time of recording or erasing is accurately decided with respect to the length of the recording signal.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a magneto-optical recording device.

Prior Art First, a conventional example will be explained based on FIG. 1 is a record carrier driven by a motor (not shown). This record carrier 1 is formed by sequentially laminating a magneto-optical recording film 3 and a protective film 4 on a transparent substrate 2. 5 is an optical pickup, and this optical pickup 5 is a laser light source (not shown).
An objective lens 6 disposed in the optical path from 1 to the record carrier 1, and an objective lens 6 arranged in the optical axis direction (focusing direction)
Alternatively, it has an actuator 7 that is driven in a direction (tracking direction) orthogonal to that direction (tracking direction). Further, a magnetic head 8 facing the recording carrier 1 on the opposite side of the objective lens 6 is connected to the optical pickup 5. The magnetic head 8 serving as the magnetic field applying means is made up of a coil 9 wound around a magnetic material, and this coil 9 is connected to the magnetic field modulating means 10. Also, as shown in Figure 6,
There is also one in which a permanent magnet 11 is opposed to the recording carrier l as a magnetic field applying means.

When recording or erasing, the laser beam is passed through the objective lens 6.
The aperture magneto-optical recording film 3 is irradiated with laser light, and the temperature of the magneto-optical recording film 3 is heated to around the Curie temperature, thereby reducing the holding power of the portion irradiated with the laser light. At this time, information is recorded or the recorded information is erased by applying a magnetic field from the magnetic head 8 or the permanent magnet 11 to the recording carrier 1 according to the recording signal. The magnetic field modulation operation is performed by modulating the current flowing from the magnetic field modulating means 10 to the coil 9 in the case of the magnetic head 8, and in the case of the permanent magnet 11, rotating the magnetic head 11 by 180 degrees with a motor or other drive unit to move the recording carrier l. This is done by reversing the magnetic poles facing each other.

Problem to be Solved by the Invention Here, as shown in FIG. 7, the output pulse of the recording signal is A, the output of the laser beam from the optical pickup 5 is B, and the magneto-optical recording is performed from the magnetic head 8 or the permanent magnet 1l. The pulse of the magnetic field applied to the film 3 will be described as D, the leakage magnetic field applied as a DC bias component from the actuator 7 to the record carrier 1, and E the recording state on the record carrier 1. As can be seen from the comparison between A and C, the direction of the magnetic field applied from the magnetic head 8 or the permanent magnet 11 to the magneto-optical recording film 3 is determined by the recording signal, and the rise and fall of the waveform of the magnetic field of the magnetic head 8 are determined by the recording signal. There is a delay in the fall. Moreover, the magnetic head 8 or the permanent magnet 1l is placed in the same direction as the direction in which the leakage magnetic field D of the actuator 7 acts on the magneto-optical recording film 3.
When the magnetic field is modulated, the magnetic field applied to the magneto-optical recording film 3 becomes stronger, and when the magnetic field is modulated in the opposite direction, the magnetic field applied to the magneto-optical recording film 3 becomes weaker. Therefore, during recording and erasing, the length of the target bit becomes longer than the length of the recording signal. In other words, record 1l! As shown in iIE, the time for bit formation (the time indicated by the arrow ↓) exceeds 50% of one cycle.

Means for Solving the Problems According to claim 1, an objective lens and a magnetic head arranged in an optical path from a laser light source to a magneto-optical recording film of a record carrier and driven by an actuator are arranged with the carrier in between. Magnetic field modulation means were arranged opposite to each other and reversed the direction in which the magnetic field of the magnetic head acts in accordance with a recording signal, and a modulation timing control means was connected to the magnetic field modulation means.

In a second aspect of the present invention, an objective lens and a magnetic head, which are disposed in an optical path from a laser light source to a magneto-optical recording film of a record carrier and driven by an actuator, are disposed opposite to each other with the record carrier in between, and a recording signal is recorded. Accordingly, a magnetic field modulation means for reversing the direction in which the magnetic field of the magnetic head acts was provided, and a magnetic field intensity control means was connected to this magnetic field modulation means.

In operation claim 1, the magnetic field modulation operation of the magnetic head can be temporally controlled by the modulation timing control means according to the magnitude of the leakage magnetic field applied from the actuator to the record carrier, so that the length of the recording signal and , it is possible to match the application time of the magnetic field for recording or erasing applied from the magnetic head to the record carrier, thereby making the bit length during recording or erasing smaller than the length of the recording signal. can be determined accurately.

In claim 2, the magnetic field intensity control means can modulate the magnetic head by increasing the magnetic field in the opposite direction to the leakage magnetic field in accordance with the magnitude of the leakage magnetic field applied from the actuator to the record carrier. The bit length during recording or erasing can be accurately determined with respect to the length of the recording signal.

Embodiment A first embodiment of the present invention will be explained based on FIGS. 1 and 2. Components that are the same as those described in FIGS. 5 to 7 are designated by the same reference numerals, and description thereof will be omitted (the same applies hereinafter).

The coil 9 of the magnetic head 8 receives the output pulse A of the recording signal.
A magnetic field modulating means 10 is connected which modulates the magnetic field of a magnetic head 8, which is a magnetic field applying means, in accordance with the magnetic field applying means. Furthermore, a modulation timing control means 12 is connected to this magnetic field modulation means 10. This modulation timing control means 12 temporally controls the magnetic field modulation operation of the magnetic head 8 according to the magnitude of the leakage magnetic field C acting on the magneto-optical recording film 3 of the record carrier I from the actuator 7.

In such a configuration, as shown in FIG. 2, when the optical pickup 5 irradiates the magneto-optical recording film 3 with the laser 9B, a leakage magnetic field D is generated from the actuator 7 to the magneto-optical recording film 3 as a DC bias component. However, in this state, when the output pulse A of the recording signal with a duty ratio of 50% is given, the modulation timing control means 12 changes the modulation operation of the magnetic field modulation means 10 according to the strength of the leakage magnetic field D. control. That is, the pulse width p' of the magnetic field pulse C in the same direction as the leakage magnetic field D is made shorter than the width p of the output pulse A of the recording signal. As a result, as shown in recording state E, a bit length with a duty ratio of 50% can be obtained.

In addition, as another method for the modulation timing control means 12 to temporally control the modulation operation of the magnetic field modulation means 1O according to the strength of the leakage magnetic field B, the width of the pulse C of the magnetic field in the opposite direction to the direction of the leakage magnetic field D can be used. A similar effect can be obtained by making pn longer than the width p of the output pulse A of the recording signal. Furthermore, even when the permanent magnet 11 (see Fig. 6) is used as the magnetic field application means, the operation of the motor (magnetic field modulation means) that rotates the permanent magnet 11 can be temporally controlled by the modulation timing control means. A similar effect can be obtained.

Next, a second embodiment of the present invention will be described based on FIGS. 3 and 4. A magnetic field intensity control means l3 is connected to the magnetic field modulation means 10.

Therefore, as shown in FIG. 4, when the optical pickup 5 irradiates the magneto-optical recording film 3 with the laser beam B, the actuator 7 applies the leakage magnetic field D to the magneto-optical recording film 3 as a DC bias component. In this state, Duty
Given an output pulse A of a recording signal with a ratio of 50%,
The magnetic field intensity control means 13 modulates the magnetic head 8 by increasing the magnetic field in the opposite direction to the leakage magnetic field D according to the magnitude of the leakage magnetic field D acting on the magneto-optical recording film 3 from the actuator 7. The magnetic field strengths of the pulse C of the magnetic field applied from the magnetic head 8 to the magneto-optical recording film 3 are H 1 and H'. As a result, Du
A bit length with a ty ratio of 50% can be obtained.

Furthermore, the same effect can be obtained by applying a DC bias magnetic field corresponding to the strength of the leakage magnetic field D to the magneto-optical recording film 3 in the opposite direction.

Effects of the Invention Since the present invention is configured as described above, the magnetic field modulation operation of the magnetic head can be temporally controlled by the modulation timing control means according to the magnitude of the leakage magnetic field acting on the record carrier from the actuator. Therefore, the length of the recorded signal and
It is possible to match the application time of the magnetic field for recording or erasing applied from the magnetic head to the record carrier, thereby making it possible to accurately determine the bit length during recording or erasing with respect to the length of the recording signal. Alternatively, the magnetic field intensity control means can modulate the magnetic head by increasing the magnetic field in the opposite direction to the leakage magnetic field in accordance with the magnitude of the leakage magnetic field acting on the recording carrier from the actuator, Therefore, it is possible to accurately determine the bit length during recording or erasing with respect to the length of the recording signal.

12 is a timing chart showing changes in a modulation operation and a record-like bear.

Claims (1)

[Claims] 1. An objective lens disposed in the optical path from the laser light source to the magneto-optical recording film of the record carrier, an actuator for driving this objective lens, and an actuator for driving the objective lens on the opposite side of the objective lens to the record carrier. It consists of magnetic field applying means facing each other, a magnetic field modulating means for modulating the magnetic field of the magnetic field applying means according to a recording signal, and a modulation timing control means connected to the magnetic field modulating means, and the modulation timing control means controls the actuator. 2. A magneto-optical recording device, characterized in that the magnetic field modulation operation of the magnetic field applying means is temporally controlled according to the magnitude of a leakage magnetic field acting on the record carrier. 2. An objective lens disposed in the optical path from the laser light source to the magneto-optical recording film of the record carrier, an actuator for driving the objective lens, and a magnetic field applying means facing the record carrier on the opposite side of the objective lens. , a magnetic field modulating means for modulating the magnetic field of the magnetic field applying means in accordance with a recording signal, and a magnetic field strength controlling means connected to the magnetic field modulating means, and the magnetic field strength controlling means applies the magnetic field from the actuator to the record carrier. 1. A magneto-optical recording device characterized in that the magnetic field applying means is modulated by increasing a magnetic field in a direction opposite to the leakage magnetic field in accordance with the magnitude of the leakage magnetic field.