JPS61170940A - Photomagnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To monitor the quantity of laser beam accurately by moving a head carriage formed by coupling an optical means and a solenoid mechanically opposite in one body relatively to a recording medium. CONSTITUTION:A feeding means 4 shifts the head carriage 3 and recording medium 1 in relative position to put the optical axis off the surface of the recording medium or remove the recording medium 1, and then laser beam converged originally on the surface of the recording medium 1 is all photodetected by a light quantity converting element 18 and converted into an electric signal, which is monitored. Thus, the quantity of the light is monitored every time the recording medium 1 is loaded or unloaded or at optional time when the actual quantity of main beam light is measured. The photoelectric converting element 18 is fixed to the solenoid 30 and the quantity of light is monitored on the same condition, so the stability of the measurement is improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a magneto-optical recording/reproducing/erasing device, and particularly relates to an improvement of a laser light amount monitor device for monitoring the amount of laser light on the surface of a recording medium in the device. .

[Conventional technology]

2. Description of the Related Art In a magneto-optical recording, reproducing and erasing device that uses a semiconductor laser as a light source, a method that uses back-emitted laser light is generally used as a method of monitoring the amount of laser emitted light. Second
The figure is, for example, published in Japanese Patent Application Laid-open No. 51-29821 (Patent No. 10).
53820) is a configuration diagram of a laser light amount monitoring device related to a conventional magneto-optical recording/reproducing/erasing device, in which 11 is a semiconductor laser, 12.13 is an optical means,
17 is a laser beam, 16 is a first photoelectric conversion element, 20
3 is a second photoelectric conversion element, 3 is an optical means, and a head carriage that mechanically couples the external magnetic field urging means; 1 is a disk serving as a recording medium; 4 is a head carriage 3 and a recording medium 1 perpendicular to the laser optical axis; This is a feeding means that changes the relative positional relationship in the direction of movement.

Next, the operation will be explained.

A semiconductor laser generally emits a laser beam in two directions, front and rear, and the beam intensities (light amounts) in these two directions are proportional to each other. A laser beam 17 (hereinafter referred to as main beam) emitted from one end of the semiconductor laser 11 in the figure is focused onto the disk surface 1 by an optical means 12.13, and the light transmitted through the disk 1 is transmitted to the first photoelectric conversion element. Entering 16,
converted into an electrical signal. This is a transmitted light monitor.

On the other hand, the laser beam 19 emitted from the other end of the semiconductor laser 11 (hereinafter referred to as after-emission light) is received by the second photoelectric conversion element 20 and converted into an electric signal, thereby increasing the intensity of the laser beam in this direction. Since this after-emission light is in a proportional relationship with the main beam, it is possible to monitor the intensity of the main beam.

[Problem that the invention seeks to solve]

As described above, the laser light intensity monitor device in a conventional magneto-optical recording/reproducing/erasing device monitors the intensity of the main beam using the back emitted light, so the amount of laser light focused on the recording medium surface is determined by the back emitted light. Monitored only indirectly. Therefore, if the transmittance of the optical means 12, 13 changes due to the influence of dust, dirt, etc., the light quantity of the main beam 17 and the after-emission light 19 focused on the surface of the recording medium will not be proportional to each other, and the monitor output will be This means that the amount of laser light on the surface is not shown correctly. Further, when the dimensions of the light receiving surface of the second photoelectric conversion element 20 are larger than the dimensions of the chip of the semiconductor laser 11,
Scattered light from the optical means 12, 13 and others may jump over the laser chip 11 and return to the light receiving surface of the second photoelectric conversion element 20, and in this case as well, the proportional relationship between the monitor output and the amount of light of the main beam is broken. For this reason, conventionally, it was necessary to remove the recording medium 1, insert a third photoelectric conversion element (not shown) into the laser beam focal point, and calibrate the actual main beam light intensity, which was a complicated operation. In addition, there were also problems with measurement stability.

In order to solve the above-mentioned problems, this invention
g i l″6″′・”ゝ*WllC1ih*t,:
,, k lr E"41 In a magneto-optical recording/reproducing/erasing device that performs raw erasing and whose signal quality largely depends on the amount of laser light on the surface of the recording medium, it is possible to stably and easily monitor the amount of light of the main beam on the surface of the recording medium. The purpose of the present invention is to provide a magneto-optical recording/reproducing/erasing device that can perform the following steps.

[Means for solving problems]

The magneto-optical recording, reproducing and erasing device according to the present invention uses a solenoid as an external magnetic field energizing means necessary for reciprocating and erasing magneto-optical recording, and a photoelectric conversion element for laser beam monitoring is attached to one end of the solenoid. , an optical means for condensing a laser beam onto the recording medium surface and the solenoid are opposed to each other with the recording medium in between, and are mechanically coupled and integrated by a head carriage, and the head carriage and the recording medium are connected to each other by the laser beam. It is provided with a feeding means for relative movement in a direction orthogonal to the axis.

[Effect]

In the magneto-optical recording/reproducing/erasing device according to the present invention, the head carriage, which mechanically couples the optical means and the solenoid, and the recording medium are moved relative to each other, and the optical axis is removed from the surface of the recording medium to perform the charging/conversion. Since the amount of laser light is monitored by the element, the amount of laser light that should originally be focused on the surface of the recording medium can be accurately monitored.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a recording medium, 11 is a semiconductor laser that irradiates laser light, 12, 15, 13 is an optical means that focuses the laser beam on the recording medium 1, and 16 is a reflected light through optical means 14 and 15. 20 is a second photoelectric conversion element that monitors the after-emission light, 30 is a solenoid that applies an external magnetic field to the recording medium 1, and 18 is a monitor that monitors the amount of light on the surface of the recording medium 1. a third photoelectric conversion element attached to one end of the solenoid 30; 2 a motor for rotating the recording medium 1; 3 a head carriage mechanically coupling the optical means 12 to 15 and the like with the solenoid 30; 4;
is a feeding means for moving the head carriage 3 in a direction perpendicular to the optical axis.

Next, the operation will be explained.

The magneto-optical recording, reproducing and erasing device of this embodiment is designed to record electric signals etc. on a recording medium and reproduce or erase them using the magneto-optical effect. Solenoid 30 is used for this purpose. This solenoid 30 is required to reverse the direction of the external magnetic field during recording and erasing, and its strength is several hundred oersteds. This condition can be easily met by changing the direction of the current flowing through the solenoid 30.

Next, the monitoring method will be explained. The main beam 17 emitted from the semiconductor laser 11 is transmitted through the lens 12° beam splitter 15. The reflected light passes through the optical means of the lens 13 and is focused onto the surface of the recording medium 1, and after passing through the lens 13, the reflected light is split by the beam splitter 15, passes through the lens 14, and enters the first photoelectric conversion element 16. converted into an electrical signal. That is, the conventional device shown in FIG. 2 monitors transmitted light, but for example, Japanese Patent Application Laid-Open No. 51-29821 (Patent No. 1053)
820), there is no problem even if the reflected light is read instead of the transmitted light, so this device reads this reflected light.

Here, when the relative position between the head carriage 3 and the recording medium 1 is changed by the feeding means 4, and the optical axis is removed from the recording medium surface, or the recording medium l is removed, the light is originally focused on the recording medium 1 surface. The amount of laser light to be output is all received by the third photoelectric conversion element 18, converted into an electrical signal, and monitored. 0 Although the figure shows an example in which the carriage is moved, it is also possible to move the recording medium. Needless to say.

Generally, in such a magneto-optical recording/reproducing/erasing device, the operation of moving the head carriage out of the surface of the recording medium is required in order to attach/detach the recording medium, so adopting the above configuration makes the operation complicated. Never. In this way, it is possible to monitor the light amount each time the recording medium is attached or removed, or at any time when it is desired to measure the actual main beam light amount.

Furthermore, since the third photoelectric conversion element is fixed to the solenoid 30, there is no need to take it out and put it in each time a measurement is performed, and since it is monitored under the same conditions, the stability of the measurement is also improved. Furthermore, in the apparatus of this embodiment, since the laser beam amount is measured at a location away from the recording medium, it is possible to prevent the recording medium from being exposed to light when setting the optical energy for recording or erasing.

In addition, in the operation of the above embodiment, an example was explained in which the amount of light is monitored using only the third photoelectric conversion element 18, but as in the case of the conventional example, the second photoelectric conversion element 20 monitors the after-emission light in real time. By using the above-mentioned monitor output results to correspond to short-term light intensity fluctuations, and calibrating the above-mentioned monitor output results for long-term light intensity fluctuations, more effective laser light intensity monitoring can be realized by using both in combination.

Note that the recording medium is not limited to the disk-shaped one described above, but may also be card-shaped or tape-shaped.

〔Effect of the invention〕

As described above, according to the present invention, a solenoid is provided facing the optical means with the recording medium in between, and a photoelectric conversion element for laser beam monitoring is attached to one end of the solenoid.
In addition, a head carriage mechanically coupled to an optical means and a solenoid, and a feeding means for relatively moving the head carriage and the recording medium in a direction perpendicular to the optical axis are provided.
Hakori.

Even if the transmittance of the optical means changes due to the influence of dust, etc., it has the effect of directly monitoring the amount of laser light that is actually focused on the surface of the recording medium, and does not require any complication to operate. do not have.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a magneto-optical recording, reproducing and erasing device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional magneto-optical recording, reproducing and erasing device. 1... Recording medium, 11... Semiconductor laser, 12.1
3.14... Lens (optical means), 15... Beam splitter (optical means), 18... Photoelectric conversion element, 3
0...Solenoid, 3...Head carriage, 4.
...Transportation means. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A laser light source that emits coherent light, an optical means that focuses the laser light onto the surface of a recording medium, and an external device that faces the optical means with the recording medium in between and is perpendicular to the recording medium. an external magnetic field energizing means for energizing a magnetic field; a head carriage in which both the optical means and the external magnetic field energizing means are mechanically coupled and integrated; and a level optical axis between the head carriage and the recording medium. In the magneto-optical recording/reproducing/erasing device, the external magnetic field energizing means includes a solenoid arranged concentrically with the optical axis incident on the recording medium. A magneto-optical recording/reproducing/erasing device characterized in that a photoelectric conversion element for monitoring the amount of laser light is attached to one end of the solenoid.