JPH0453048A - Magneto-optical recorder - Google Patents

Abstract

PURPOSE:To prevent a pit or pits from remaining unerased due to temp. fluctuations and to improve the quality of a signal by controlling light beam power with a detecting value of an ambient temp. of a medium. CONSTITUTION:A temp. detected by a detector 15 is inputted to a temp. laser power target value calculation circuit 16, and a target value of the laser power corresponding to this temp. is settled. The target value is sent to a laser driver 17, and the power of laser light emitted from a semiconductor laser 5 is controlled to be equalized to the target value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an overridable magneto-optical recording device.

[Prior Art] Conventionally, a magneto-optical recording device as shown in FIG. 3 has been proposed which performs overwriting by reversing the direction of an externally applied magnetic field in accordance with a recording signal.

In FIG. 3, 1 indicates a magneto-optical disk, and 2 indicates a magnetic film. This magneto-optical disk 1 is rotatably driven by a motor 3.

Information is recorded and/or reproduced onto this magneto-optical disk l by an optical pickup 4. The optical pickup 4 has a built-in semiconductor laser 5 as a light source. The linearly polarized light beam emitted from this semiconductor laser 5 passes through a collimating lens 6 and a beam splitter 7a, and is focused into a magneto-optical disc by an objective lens 8.

On the other hand, the light reflected by the magneto-optical disk 1 passes through the objective lens 8 again and is separated from the incident light by the beam splitter 7a. The separated light is split into two by the beam ssolitter 7b, and the force is received by the sensor 10a via the sensor 9a. So, this optical sensor 1.
7. Based on the Jl force of Oa, the AT and AF circuits 11 “
C. A focus error signal and a tracking error signal are detected. The stiff error signal is input to the actuator 12 and driven by the objective lens 8.
It will be done.

The other light is Saram: dual polarized beam splitter 7c
The light is divided into two parts, and each light is sent to sensor lenses 9b and 9c.
Via - (optical sensor 10b.

The light is received at 10c. The polarizing beam splitter 7c is rotated by 45 degrees around the optical axis so that the direction of the polarization power of the incident and transmitted light is 45 degrees with respect to the polarization direction of the light incident on the medium. I'm trying to arrange it. Therefore, the phases of the information components ζ and lq of the signals output from the optical sensors 10b and 1Oc are reversed, and the reproduced signal is obtained by dividing the outputs of these optical sensors by y.

The optical pickup 4 directs constant intensity 1)---1+ light continuously emitted from the liquid conductor 5 to the magnetic film 2 of the magneto-optical disk l. The target is irradiated and the temperature of the magnetic film 2 in this open area is reduced to 1.
It must be configured so that it can be used.

Further, 13 indicates an electromagnet for applying a magnetic field to the magnetic film 2 of the magneto-optical chip 71, and in this example, C is the electromagnet 13 or the magnet installed on the opposite side of the CC optical pickup across the magneto-optical disk 1. I'm here. Further, the electromagnet 13 has a #4 structure so as to be movable in the J direction of the radius of the magneto-optical disk 1 in conjunction with the optical pickup 4.

14 indicates a magnetic field modulation circuit. This magnetic field modulation circuit 14 is
Depending on the input recording signal, the direction of the radio waves flowing through the coil 13B wound around the electromagnet 13 is reversed.

For example, when the signal level of the recording signal is high level ``1'', the electric wire 2 flowing in the direction shown by the arrow IA is connected to the coil 1.
3B, and when the signal level is low level "0", the current flowing in the direction shown by arrow IB is supplied to coil 13B.
supply to.

When the signal level of the recording signal is high, a magnetic field with the polarity shown by the arrow HA is generated from the electromagnet 13, and when the signal level of the recording signal is low, I1. Q
When H, a magnetic field with the polarity shown by the arrow HB is generated.

The magnetic fields shown by arrows HA and HB are either different in direction or have the same strength. Also, considering the directions of the magnetic fields shown by arrow HA and the magnetic field shown by arrow HB, and assuming that they are He and -He, respectively, l±Hel is the direction of the magnetic domain of the magnetic film heated by the light beam. It is said that the strength is such that it can be oriented.

In the magneto-optical disk device configured in this way, for example, when a recording signal as shown in FIG. 4(a) is input to the magnetic field modulation circuit, the electromagnet 13 operates as shown in FIG. 4(b). A magnetic field is generated and applied to the magneto-optical disk l. Further, on the magneto-optical disk l, there is a magnetic film 2.
The fourth [ff! (
A laser beam having a constant intensity W as shown in c) is irradiated. Therefore, the magneto-optical disk 1 has bits 4a, 4b, 4c, 4d - as schematically shown in FIG. 4(d, ).
or is formed.

According to this magneto-optical recording device, it is possible to record new information by overwriting the information, regardless of the information previously written on the magneto-optical disk 1.

[Problem to be solved by the invention] However, in the above conventional example, if the laser power fluctuates during recording or the ambient temperature changes, I! It is conceivable that previously recorded bits may not be completely erased and may remain.

For example, if the laser power of the previous recording is higher than the reference value, and if you overwrite it with a laser power of the reference value or lower value, the newly recorded bit 21 will become as shown in Figure 2. It will be smaller than the previously recorded bit 20. Therefore, the media is
It's like an eraser or raw 1. Ru. Also, if it is lower than the ambient temperature or reference temperature when previously recorded, for example, when the temperature is higher than room temperature and the alarm is 4°,
Similar eraser remains, Rika is still alive. Furthermore, there are cases in which the radar power fluctuation and the peripheral 1i4 degree change occur at the same time, and the possibility that bits are erased due to various causes and the remaining bits are left alive.

If the true information, PI-, is reproduced while including the erased/remaining PI-1, there is an inconvenience that the quality of the reproduced signal deteriorates.

The purpose of the present invention is "9. Solving the problems of the conventional technology,
It is an object of the present invention to provide a magneto-optical recording device that can satisfactorily overwrite information without leaving any previously recorded information unerased. The purpose is to scan a magneto-optical recording medium with a light beam and apply a magnetic field whose polarity changes in accordance with the information signal near the area of the medium to be scanned.
In a magneto-optical recording device that records information, the temperature around the medium is expressed as cypress, l, j l, detected temperature 1,
1, and then control the +-jii recording beam.゛To 9j, ゛,'' will be created quickly.

Embodiment FIG. 1 is a schematic diagram showing an embodiment of the magneto-optical recording head office of the present invention. In FIG. 1, the same members as in FIG.・Detailed explanation will be omitted.

This embodiment C differs from the apparatus shown in FIG. 3 in that a temperature detector 15 for detecting the ambient temperature of the magneto-optical disk 1 is provided. The temperature detected by the temperature detector 15 is input to the temperature [. - power 1] target value calculation circuit] 6. This circuit 16 is designed to prevent the bit size written to the C disk from changing depending on the ambient temperature.
Set the target value for servants. That is, the circuit 16 increases the target value if the detected temperature is low, and increases the target value if the detected temperature is high.
Decrease the target value.

The laser power target value calculated by the circuit 16 in section 8 is sent to the laser driver 17゛C, and this driver 17
is controlled so that the power of the laser light emitted from the semiconductor laser 5 is equal to this target value. Community-wise,
The laser I/lar bar 17 receives a portion of the laser beam actually emitted from the semiconductor laser and detects the power of the laser beam by a configuration not shown. Then, the detected power is compared with the target value described above, and the amount of current supplied to the semiconductor laser 5 is adjusted based on the difference.

In this embodiment, the temperature detector 15 is placed near the objective lens 8 of the optical pickup 4. This is to detect the ambient temperature as close as possible to the area on the disc where information is written.

In this embodiment, the operations other than the temperature detection process described above are exactly the same as those of the apparatus shown in FIG. Therefore, detailed explanation will be omitted.

[Effect] As explained below, the magneto-optical recording device of the present invention detects the ambient temperature of the medium and adjusts the power of the optical beam irradiated to the medium in accordance with the detected temperature. Since this is controlled, it is possible to prevent bits from being left unerased due to temperature fluctuations. In addition, it can be realized by providing a temperature detector and a 1t116 circuit attached to it.
It has the advantage of being simple in terms of equipment and low in cost.

[Brief explanation of the drawing]

Fig. 1 is a small schematic diagram of an embodiment of the magneto-optical recording device of the present invention, Fig. 2 is a schematic diagram for explaining the occurrence of unerased bits, and Fig. 3 is a conventional magneto-optical recording device. There is a schematic IA showing an S configuration example of the system U, and Figure 4 is a schematic diagram for explaining the principle of overwriting information. 1. Magneto-optical disk 4. Light and pickup 5.・Cliff conductor laser 15...Temperature detector 16...Temperature-laser power target 4rM calculation circuit 17
・・・Laser try 8-

Claims (2)

[Claims] (1) While scanning the magneto-optical recording medium with a light beam,
In a magneto-optical recording device that records information by applying a magnetic field whose polarity changes according to an information signal near a scanned area of the medium, the temperature around the medium is detected, and the detected temperature is A magneto-optical recording device characterized in that the power of the light beam is controlled according to the power of the light beam. (2) The light beam is irradiated onto a medium from an optical pickup, and a detector for detecting the ambient temperature is provided on a side of the optical pickup facing the medium. Magneto-optical recording device.