JPH0273549A - Optical recording medium and its driving device - Google Patents

Abstract

PURPOSE:To increase memory capacity and to prevent the erasing of information due to malfunction by forming a recording pit to record the unwritable read-only information in a groove for the tracking of a magneto-optical disk. CONSTITUTION:A writable magnetic pit 5e subjected to perpendicular-magnetic- recording by a magnetic head is formed in a magnetized layer 5b on a land part 5d between grooves 5c for the tracking and the direction of magnetization is made different in accordance with recording and erasing. A long-hole recording pit 5f to record the unwritable information is formed in the grooved 5c. Since the information to be read and written at any time and the read-only information can be recorded by the two pits 5e and 5f, there is no danger of erasing the read-only information. The information can be recorded in the groove which is not used for recording formerly. Thus, the memory capacity is increased and the erasing of the information due to the malfunction can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magneto-optical disk and its drive device.
More specifically, the present invention relates to a magneto-optical disk with improved recording density and a drive device for the same.

[Conventional technology]

Magneto-optical disks were developed as rewritable high-capacity recording media.

FIG. 2 is a schematic diagram showing a conventional magneto-optical disk and its drive device. In the figure, 5 is a magnetized layer 5b on a substrate 5a.
This is a disk-shaped magneto-optical disk (hereinafter referred to as a disk) formed by laminating layers, and the substrate 5a of the disk 5 has an annular tracking groove 5c extending from its inner circumference to its outer circumference.
5c... are formed and used for positioning the optical head l and magnetic head 6, which will be described later, when accessing the disk 5.

Land portion 5d between tracking grooves 5c, 5c...
, 5d .
... are formed, and the direction of magnetization thereof is different depending on whether information is recorded or erased.

An objective lens 1a that focuses the laser beam irradiated from the optical head 1 faces the lower surface of the disk 5, and the focused laser beam is irradiated onto the magnetized layer 5b with a diameter of 1 to 2 microns. Further, a magnetic head 6 that applies a bias magnetic field to the upper surface of the disc 5, which is opposite to the laser beam irradiation position, faces the upper surface of the disc 5. The optical head 1 includes a laser source, an optical system, and a photodetector, and is supplied with a servo signal from a servo circuit 4 to drive the objective lens 1a of the optical head 1 for tracking and focusing. A recording signal is also provided for recording information by modulating the light intensity of the laser beam.

Further, the photodetection output of the optical head I is given to a polarization angle detector 3, where the polarization angle is detected, thereby determining the direction of magnetization and reproducing the recorded signal.

[Problem to be solved by the invention]

With conventional disks and their drive devices configured in this way, if you input non-writable information such as software O3 and programs that should not be erased, it is necessary to prohibit writing. Since the prohibition is left to human judgment, there is a risk that information may be lost due to erroneous operation or unforeseen accidents.

Furthermore, since information is only recorded on the land portion, its capacity is limited, making it difficult to increase the capacity.

This invention has been made in view of the above circumstances, and provides an optical recording medium and an optical recording medium that can prevent erasure of non-writable information and increase storage capacity by forming a read-only recording pitch in a tracking groove. The purpose of the present invention is to provide such a drive device.

[Means to solve the problem]

The optical recording medium according to the present invention has non-rewritable information recorded in either the tracking groove or the other part, and rewritable information is recorded in the other part. The drive device is provided with non-rewritable information detection means for detecting the non-rewritable information and rewritable information detection means for detecting the rewritable information.

[Effect]

In the first aspect of the present invention, non-rewritable information is recorded in advance on either the tracking groove or the other portion, and rewritable information is recorded on the other. In the second invention, the recorded non-rewritable information is detected by the non-rewritable information detection means, and the rewritable information is detected by the rewritable information horizontal means.

〔Example〕

The present invention will be explained below based on the drawings showing one embodiment thereof. FIG. 1 is a perspective view showing the structure of a magneto-optical disk, which is a magneto-optical recording medium according to the present invention, and a schematic block diagram showing the structure of a drive device thereof. In the figure, reference numeral 5 denotes a disk-shaped magneto-optical disk (hereinafter referred to as a disk) formed by laminating a magnetized layer 5b on a substrate 5a. Tracking grooves 5c, 5c... are formed in the grooves 5c, 5c...
Optical head 1 and magnetic head 6 when accessing the disk 5
It is used for positioning.

Land portion 5d for tracking between 5c and 5c...
, 5d... are formed with writable magnetic pits 5e, 5e... which are perpendicularly magnetically recorded by a magnetic head 6 facing the upper surface thereof, and the magnetization direction thereof is determined according to information. This differs depending on whether the data is recorded or erased.

Further, elongated recording pits 1-5f, 5f, . . . for recording non-writable information such as O3 and programs in software are formed in advance in the tracking grooves 5c, 5c, .

Because these two pits 5e and 5f allow read/write information and read-only information to be recorded in separate pits 5e and 5f, there is no risk that the read-only information will be erased. In addition, recording pits 5e, 5e...
By forming this, the storage capacity of the disk 5 is doubled.

Next, a magneto-optical recording medium drive device according to a second invention will be explained.

An objective lens 1a that focuses the laser beam irradiated from the optical head 1 faces the lower surface of the disk 5, and the focused laser beam is irradiated onto the magnetized JiSb with a diameter of 1 to 2 microns. The optical head 1 includes a laser source, an optical system, and a group of photodetectors, and is supplied with a servo signal from a servo circuit 4 to drive the tracking and focus of the objective lens 1a of the optical head 1. Further, the optical head 1 is given a recording signal for recording information by modulating the amount of laser light.

The output signals of the photodetector group of the optical hand l are given to the light amount detection circuit 2, which is a non-writable information detection means, and the polarization angle detection circuit 3, which is a writable information detection means, and the magnetic pits 5e,
In order to prevent crosstalk between the information recorded in the recording pits 5e, 5e, and the recording pits 5f, 5f, and so on, the two detection circuits 2 and 3 detect the respective information.

In the optical recording medium and its driving device configured in this way, non-erasable read-only information is recorded on pre-formed recording pits) 5e, 5e, etc., and the light quantity detection circuit 2 of the driving device The information read and written at any time is modulated in light intensity by the optical head 1 according to the recording signal, and is irradiated onto the disk 5 with a diameter of 1 to 2 microns. At the same time, a bias magnetic field applied in advance is applied to the irradiation position. A bias magnetic field of opposite polarity is applied by the magnetic head 6, forming magnetic pits 5f, 5r, . . . , and information is recorded. Further, the recorded information is detected by a polarization angle detection circuit 3 to detect a difference in polarization angle due to a difference in polarity, and is thereby read.

In the above embodiment, the case where the present invention is applied to a light modulation type drive device has been described, but it goes without saying that the present invention is not limited to this and can be applied to a magnetic field modulation type drive device.

〔Effect of the invention〕

As explained above, in the first aspect of the present invention, the storage capacity can be increased by forming recording pits for recording non-writable, read-only information in the tracking groove of the magneto-optical disk. It also has the effect of preventing information from being erased due to erroneous operations or unexpected accidents.

Further, in the second invention, by providing separate detection means for detecting non-writable information and writable information, it is possible to detect writable information recorded in the magnetic pits and non-writable information recorded in the recording pits. This has the effect of preventing crosstalk with information.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the structure of a magneto-optical disk, which is an optical recording medium according to the present invention, and a schematic diagram showing the configuration of its drive device in block form. FIG. 2 is a diagram showing the structure of a conventional magneto-optical disk. FIG. 2 is a perspective view and a schematic diagram showing the configuration of the drive device in block form. 2... Light amount detection circuit 3... Polarization angle detection circuit 5...
- Magneto-optical disk 5c...Groove 5d...Land portion 5e...Magnetic pit 5f...Recording pit Note that in the drawings, the same reference numerals indicate the same or equivalent parts. Agent Masu Oiwa Yukazu

Claims (1)

[Claims] 1. An optical recording medium equipped with a tracking groove,
An optical recording medium characterized in that non-rewritable information is pre-recorded in one of the grooves or other parts, and rewritable information is recorded in the other part. 2. The optical recording medium drive device according to claim 1, further comprising: rewritable information detection means for detecting the rewritable information; and non-rewritable information detection means for detecting the non-rewritable information. Characteristic optical recording medium drive device.