JP2726033B2 - Information recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus for recording information on a disk in which a laser power condition at the time of recording is formed as an uneven array. 2. Description of the Related Art Conventionally, as for a recording disk represented by a magneto-optical disk, as disclosed in JP-A-59-81671, the recording conditions are set for each disk after the disk is manufactured. It was common to record. However, recording the recording conditions for each disk requires a great amount of work and is not suitable for mass production. Furthermore, if information is erroneously recorded on a track on which recording conditions are recorded, the recording conditions may be erased by overwriting. Therefore, a disk which is excellent in mass productivity and has no risk of erroneous erasure and a recording device which records information on the disk are required. Accordingly, the disk recording apparatus of the present invention stores a guide for a recording track on the surface of a plastic substrate, and information on the condition of laser power at the time of recording at a position preceding the guide. In an information recording / reproducing apparatus for forming information on a disk formed by forming a recording film on the surface of the guide and the irregularities, the irregularities are recorded before starting the recording operation. Control means for optically reproducing with a reproducing pickup, detecting a laser power condition at the time of recording, and setting a laser power at the time of recording of the recording / reproducing pickup based on the detected laser power condition at the time of recording. It is characterized by having. An embodiment of the present invention will be described below with reference to the drawings. 1 is a plan view of an information recording medium, FIG. 4 is a perspective view, FIG. 2 is a diagram showing a format in which information relating to recording and reproduction conditions is recorded, and FIGS. FIG. 1 is a block diagram of an information recording / reproducing apparatus to be used. In FIG. 1, reference numeral 1 denotes a magneto-optical disk (information recording medium). A through hole 2 is provided in a central portion, and the through hole 2 is clamped by an information recording / reproducing device.
The disk 1 is rotated. 3 is a magneto-optical recording part,
Its structure is as shown in FIG. That is, a perpendicular magnetization film 5 (shown by hatching) of GdTbFe, TbFeCo, or the like is provided on a plastic substrate (polycarbonate, acrylic) 4 on which a guide groove 4a (this portion becomes a recording track) is formed by evaporation or sputtering. . A protective layer 6 made of a dielectric is formed on the perpendicular magnetization film 5. Inside the magneto-optical recording portion 3, there is provided a recorded portion 7 in which information signals relating to recording and reproduction conditions are recorded. The method of recording the information signal on the recorded portion 7 is a method of recording as uneven pits 8 on the plastic substrate 4 like a compact disk, or removing the perpendicular magnetization film 5 like a write-once disk. The recording method can be considered. In the recorded portion, an aluminum reflection film may be formed instead of the perpendicular magnetization film. According to the recording method described above, an already recorded information signal can be read by a change in the amount of light reflected from the disk 1. The method of recording in the form of uneven pits is advantageous because pits can be created when the guide groove 4a is formed, and there is no possibility of erasing.
The laser beam is emitted from the plastic substrate 4 as shown by the arrow A. As a format in which information relating to recording and reproduction conditions is recorded, in a device that can also use a compact disc, the subcode Q of the compact disc is used.
Use channel format. The format of the subcode Q channel is as shown in FIG. Of these, 0001, 001 in the four bits of the address
0,0011 is a significant pattern for compact discs, while other patterns are meaningless for compact discs. Therefore, the recorded portion 7 of the magneto-optical disk 1 is
For example, 1000 patterns are recorded in the address portion of the format of the subcode Q channel. In the 72-bit data portion, information relating to recording (including erasure) and reproduction conditions of the magneto-optical disk is recorded. This information relates to, for example, laser power, linear velocity, intensity and direction of a bias magnetic field during recording, erasing, and reproducing. Alternatively, a specific pattern can be recorded to indicate the beginning of the magneto-optical recording portion 3 (or the end of the recorded portion 7). That is, the specific pattern is used as a mark indicating the reference position, and data on the number of rotations and time up to the start of the magneto-optical recording portion is recorded. The conditions for recording and reproduction are required for the following reasons. That is, as described above, GdFe, TbFe, Tb
There are FeCo and the like, but if the composition is different, the conditions of the laser power and the bias magnetic field are naturally different.
This is because, even in a material based on eCo, when the proportion of Co increases, the Curie point increases, so that it is necessary to increase the laser power for recording and erasing. Therefore, if the laser power at the time of recording, erasing, and reproducing, the intensity of the bias magnetic field at the time of recording and erasing, or the required linear velocity is written in the recorded portion 7, the information recording / reproducing apparatus can be used as a recording material. To different types of magneto-optical disks. Also, even if the recording material is the same, the magnetization direction of the magneto-optical recording portion in the non-recording state may differ depending on the standard, so that information for specifying the direction of the bias magnetic field at the time of recording and erasing is recorded. It is effective to be done. Next, a first embodiment of an information recording / reproducing apparatus using the above disc will be described with reference to FIG.
In FIG. 3, reference numeral 10 denotes a semiconductor laser as a laser light source;
11 is a collimator lens, 12 is a first polarizing beam splitter, 13 is an objective lens, 14 is a disk, and 15 is 1
/ 2 wavelength plate, 16 is a polarizing beam splitter, 17, 18
Is a photodetector, 19 and 20 are changeover switches for switching the outputs of the photodetectors 17 and 18, 21 is an adder (non-differential reproduction circuit), 22 is a differential amplifier (differential reproduction circuit), and 23 is A decoder 24 is a control circuit. Reference numeral 25 denotes a bias magnetic field applying means. When a disk (information recording medium) is mounted, there are two possibilities of this disk: a magneto-optical disk and a compact disk. Therefore, the information recording / reproducing apparatus reads the recorded state of the magneto-optical disk or the read-in state of the lead-in part of the compact disk. Becomes That is, each of the changeover switches 19 and 20 is a
And the outputs of the photodetectors 17 and 18 are
Only applied to. Then, since the pickup 26 is at the reading start position, the intensity of the reflected light from the disk changes in accordance with the information recorded in the lead-in portion or the recorded portion. Since the outputs of the photodetectors 17 and 18 change in accordance with the strength change, a reproduced HF signal is obtained by adding the outputs of the photodetectors 17 and 18 (using one photodetector having a large output change). May be). The reproduced HF signal is decoded by a decoder 23 and supplied to a control circuit 24. The control circuit 24 controls the device according to the read information signal. First, when the 4-bit address of the subcode Q channel is 1000 as described above, it is determined that the disk is a magneto-optical disk, and the changeover switches 19 and 20 are set.
Is controlled to select the b side. In the case of a magneto-optical disk,
Information related to recording and reproduction is read, and the control circuit controls the semiconductor laser 10, the bias magnetic field generating means 25, and the spindle motor for rotating the disk according to the information. That is, while information is being read from the recorded portion 7, the changeover switches 19 and 20 must select the a side. Therefore, in a medium in which a specific pattern is recorded at the end of the already-recorded portion 7, the changeover switches 19 and 20 may be switched to the b side by detecting this specific pattern. At the same time, the counter value indicating the position of the pickup 26 is cleared. When data relating to the time until the start of the magneto-optical recording portion 3 is recorded, the data may be read and switched to the b side after a predetermined time has elapsed. The above operation is easily realized by the control circuit 24 (comprising a microcomputer or the like). When the magneto-optical disk is mounted on the information recording / reproducing apparatus, the above-described determination is first performed. When a reproduction operation is designated, a predetermined power is supplied to the semiconductor laser 10 under the control of the control circuit 24. The light from the semiconductor laser 10 is collimated by the collimator lens, and is converted into linearly polarized light (P-polarized light) by reflecting the S-polarized light by the first polarizing beam splitter 12. This linearly polarized light is
The light is condensed by 3 and irradiates the magneto-optical recording portion of the magneto-optical disk 14, and the plane of polarization of the reflected light rotates according to the recorded information. In this reflected light, the P-polarized light component is changed by about ± 0.3 degrees (that is, the S-polarized light component is generated). When the light again enters the first polarization beam splitter 12, the P polarization component is reflected by about 30%,
The change in the rotation angle is enlarged by reflecting 100% of the polarized light component. The reflected light in which the change in the rotation angle is enlarged is １ ／.
The polarization plane is rotated by the wave plate 15, and is separated into a P-polarized component and an S-polarized component by the second polarization beam splitter 16, and is incident on the corresponding photodetectors 17 and 18, respectively. The outputs of the photodetectors 17 and 18 are supplied to a differential amplifier 22, whereby a magneto-optical reproduction HF signal is obtained. On the other hand, when a recording or erasing operation is designated after the mounting of the magneto-optical disk, the laser power, the strength and direction of the magnetic field, and the state of the disk rotation control according to the mode are determined based on the read information. Set by the control circuit. Also, the start position of the magneto-optical recording part is set and used for subsequent access. Then, recording and erasing operations are performed. If 1000 is not recorded in the 4-bit address of the subcode Q channel, it is determined that a compact disc is loaded, and the changeover switch 1
In 9 and 20, the a side remains selected, and the HF signal of the compact disk is obtained from the adder 21. In the above embodiments, a magneto-optical disk is used as an information recording medium. However, the present invention is applicable to an additional type optical disk or the like in which the reflectance is changed by irradiating light or removing the recording film or changing the property. You may use it. or,
Information on the condition may be recorded in a portion other than the reading start portion. Further, the configuration of the information recording / reproducing apparatus may be configured as shown in FIG. 5 (second embodiment). As described above, according to the present invention, it is possible to record a laser power condition at the time of recording by a method suitable for mass production, and furthermore, to a disc in which the condition is not erroneously erased. Information can be recorded reliably.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view of a disk of the present invention. FIG. 2 is an explanatory diagram of a recording format of a disc of the present invention. FIG. 3 is a block diagram of a reproducing circuit of the disk recording / reproducing apparatus according to the first embodiment of the present invention. FIG. 4 is a cutaway perspective view of a main part of the present invention. FIG. 5 is a block diagram of a reproducing circuit of a disk recording / reproducing apparatus according to a second embodiment of the present invention. [Description of Signs] 1 magneto-optical disk 3 magneto-optical recording portion 4a guide groove 7 recorded portion 8 pit 10 semiconductor laser 24 control circuit

Claims (1)

(57) [Claims] A guide for a recording track on a surface of a plastic substrate, and a concavo-convex array including information on a laser power condition at the time of recording are formed at a position preceding the guide, and a recording film is formed on the surface of the guide and the concavo-convex array. In an information recording / reproducing apparatus that records information on a disc formed by forming a laser beam, before starting a recording operation, optically reproduce the concave / convex array with a recording / reproducing pickup to detect a laser power condition at the time of recording, An information recording / reproducing apparatus, further comprising control means for setting a laser power at the time of recording of the recording / reproducing pickup based on the detected laser power condition at the time of recording.