JPS5971144A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To attain selectively permanent recording or erasable recording, while the recording medium is loaded in the recorder, by providing a reversible recording area and irreversible recording area on the same side of the optical information recording medium. CONSTITUTION:There exists the relation of Tc<Tm between the Curie temperature Tc of a magnetic recording thin film 23 of a disc 24 and a melting point Tm of a recording thin film 22. In information not requiring permanent storage, a recording head 31 is carried to the reversible recording area B of the disc 24, the light beam having the energy where the recording medium temperature To has the relation of Tm<To<Tc is irradiated on the magnetic recording thin film 23 by controlling the laser light source 40 so as to form the pit where the magnetization direction is inversed and the information is recorded. In case of the information requiring permanent storage, the recording head 31 is carried to the irreversible recording area A of the disc 24, the optical beam from the laser light source 40 is controlled to the energy so as to give the relation of To<Tm to the recording medium temperature To, the pit is formed by irradiating the beam onto the recording thin film 22 and the information is recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical information recording medium capable of optically recording and reproducing information.

The optical information recording media mentioned above can be roughly divided into reversible recording media that can erase information once recorded and then record it again, and media that cannot erase or re-record information as described above. There is a possible irreversible recording medium. Examples of such conventional optical information recording media will be explained with reference to FIGS. 1A and 2B and FIGS. 2A and 2B.

FIG. 1 (N is a schematic diagram showing the state of irreversible recording on an optical disc.

Here, the original disk 1 is a recording material 'on a glass disk, for example.
It is made by vapor depositing re and is rotated by a motor. During recording, a laser beam modulated based on information is emitted from a laser light source 2, collimated by a collimator lens 3, passed through a beam splitter 6, and then a beam of about 11 m is projected onto the surface of the optical disc 1 by a condensing lens 5. Irradiate at the diameter. The energy of this laser beam melts the recording material To, forming depressions, that is, pits 10 as shown in FIG. 1(B), and information is recorded.

During playback, a laser beam is focused on the original disc on which information is recorded, and this reflected light is made into parallel light again by a lens 5, deflected by a beam splitter 6, and focused onto a light receiving element 8 by a lens 7. , guides the electric signal generated by the light receiving element 8 to a signal processing surface 189.

Here, the energy of the laser beam during reproduction is controlled to an energy that does not dissolve the recording material.

At this time, the reflectance is different between the part where the bit 10 is formed and the other parts, and depending on the presence or absence of the pin 10, the light receiving element 8
The electrical signal obtained from changes.

This electrical signal becomes an electrical signal with a different time length at a binary level depending on the length of the recorded bit 10,
Recorded information can be read out by signal processing this.

FIG. 2(A) is a schematic diagram illustrating a magneto-optical disk as an example of reversible recording. Here, the magneto-optical disk 11 is
For example, Gd, Tb, ? A magnetic film having a composition such as e is deposited by sputtering,
Rotated by a motor. When recording, laser light source 1
2 emits a laser beam modulated based on the information,
Collimator lens 13 creates parallel light, polarizing plate 6
1. After passing through the half mirror 16, the beam is irradiated onto the surface of the magneto-optical disk 11 by the focusing C lens 15 with a beam diameter of about 1 μm. Although the magnetic film of the magneto-optical ice cube 11 is magnetized in advance with its orientation aligned in the perpendicular direction, the energy of the laser beam causes the temperature of the irradiated portion to reach the Curie point temperature of the magnetic film, causing the magnetization direction to fluctuate randomly. Next, when the position of the light beam moves to another part as the disk rotates, the temperature decreases, and the magnetization direction is re-magnetized by the surrounding magnetic flux in the opposite direction to that of the surroundings. In this way, information is transferred to the magnetic film by reversing the magnetization, and the light beam is irradiated onto the bit force train formed on the magnetic film, and the magnetic nine-effect rotates the plane of polarization according to the magnetization direction of the irradiated area. It is reflected as the original source. This reflected light is converted into a half mirror (change direction,
By detecting the north direction, information is reproduced in the same way as the optical disc.

At this time, the output of the light beam is suppressed so as not to cause magnetization reversal in the irradiated area.

In addition, when erasing recorded information, the bit 20 is irradiated with the same light beam as during recording, the temperature of the magnetic film is raised to the Chiesi point, and the same magnetic field is applied in the same direction as the magnetization direction around the bit. Recorded information can be erased by lowering the temperature and aligning the magnetization direction to the same direction as the surroundings.

Reversible recording media and irreversible recording media as described above are suitable for permanent recording because they can be preserved. However, since it is impossible to erase the recording, when recording t#@i that will become unnecessary after being recorded for a short period of time, it must be recorded one after another in a new recording area, which increases the media cost. There were some drawbacks.

On the other hand, since recording and erasing is possible in reversible recording media such as magneto-optical disks, the above-mentioned drawbacks of irreversible recording media can be overcome by erasing unnecessary information and using the medium repeatedly. . However, the recording material of the reversible recording medium generally deteriorates easily and is not suitable for long-term storage. Furthermore, for example, magneto-optical disks have the disadvantage that if eight colors are accidentally exposed to a strong magnetic field, the recorded information will be erased.

However, in general, information that needs to be stored permanently and information that is unnecessary are always mixed together. Therefore, there is a need for an optical information recording device that can share a reversible recording medium and an irreversible recording medium, but even in this case, the two types of recording medium must be replaced depending on whether or not permanent recording is required.

SUMMARY OF THE INVENTION In view of the above facts, an object of the present invention is to provide an optical information recording medium that can selectively perform permanent recording or erasable recording while being attached to a recording device.

The present invention achieves the above object by providing a reversible recording area and an irreversible recording area on the same side of the optical information recording medium in an optical information recording medium in which information can be recorded and stored optically. It is something that can be achieved.

3(A) is a partially cutaway perspective view, and FIG. 3(B) is a partially cutaway perspective view.
) is a schematic cross-sectional view. Here, 21 is a disk-shaped substrate made of glass or plastic such as polymethyl methacrylate or polycarbonate. An irreversible recording area A is formed on the inner circumference of the substrate 21 using low melting point substances such as Bi, Te, etc., or these substances and S, As, Ge.
, O, O, etc., is formed by a method such as vapor deposition. Further, on the outer periphery of the substrate 21, as a reversible recording area B, a magnetic recording thin film is formed by co-depositing M transfer metals such as ye, Oo, Ni, etc. and rare earth metals such as Tb, D3r, Gd, Ha, etc. by sputtering. 23 is formed, and the optical information recording medium (hereinafter referred to as a disk) 24 is formed as a whole.

Next, the state of recording and reproduction in the above embodiment will be explained with reference to FIG.

FIG. 4 is a schematic diagram showing an example of an optical information recording/reproducing device.

This device has a laser light source 40. Collimator lens 41° polarizing beam splitter 42. Deflection mirror 43. Tracking mirror 44. Autofocus lens system 45° condensing lens 46
．． It has a recording head 31 including an optical system consisting of a light receiving element 47, and records information by irradiating a recording medium with a light beam. Further, 32 is a reproducing head, and a laser light source 5
0. Collimator lens 51. Polarizing plate 5 days, half mirror
52° deflection mirror 53. Tracking mirror 54. Autofocus lens system 55. Condensing lens 56. It has an optical system consisting of an analyzer 59 and a light receiving element 57, and reproduces the information recorded on the recording medium by irradiating the recording medium with a light beam and detecting the reflected light. It is something.

The recording head 31 and the reproducing head 32 are driven by pulleys 34, 35, 36, 379 along a guide 33 fixed to the head 30 by a drive motor (not shown). (If necessary, the output of the laser light source 50 of the reproducing head 32) is controlled by a drive circuit (not shown), and the energy of the original beam irradiated to the recording medium is switched, so that it can be used for either a reversible recording medium or an irreversible recording medium. It is also possible to record and reproduce information.

Consider the case where information is recorded on the disc 24 according to the present invention using the apparatus shown in FIG. Generally, there is a relationship Tc (Tm) between the Curie point temperature TO of the magnetic recording thin film 23 of the disk 24 and the melting point Tm of the recording thin film 22. For example, T used for the recording thin film 22.

The melting point Tm of is around 430°C, and the Curie single point temperature T of re, 6GdHTk) + 2 used for the magnetic record book @23
c is approximately 18σC. Information is recorded in the following manner.

(1) For recording information that does not need to be permanently stored, the rad 31 is sent to the reversible recording area B of the disk 24, and the laser beam 111ii40 is controlled by a drive circuit (not shown) so that the recording medium temperature To becomes Tm) A light beam with energy such that To ) Tc is transmitted to the magnetic recording thin film 2.
3, and in a process similar to that of the magneto-optical disks shown in FIGS. 1A and 1B, bits with reversed magnetization directions are formed and information is recorded. At this time, the irreversible recording area A was accidentally
Even if the light beam is irradiated, it does not affect the recording thin film 22 due to the relationship Tm ) To.

(0) Recording head 31 for information that needs to be permanently stored
is sent to the irreversible recording area A of the disk 24. here,
The light beam from the laser light source 40 is controlled to have an energy such that the recording medium temperature TO becomes 'ro) Tm, and the recording thin film 22 is irradiated with such a light beam, and the recording thin film 22 is irradiated with the light beam. Pitts are formed and information is recorded using the same process as in the optical disc shown in Figure (A) (B).

When reproducing the information recorded as described above, the reproducing head 32 is scanned over the disk 24 to adjust the recording medium temperature To.
A light beam having an energy such that To<Tc is irradiated onto the magnetic recording film 23 and the recording thin film of the disk 24,
By detecting the reflected light, the
) and the information is reproduced by a process similar to that described in FIGS. 2(A)s(B). Here, if necessary, the energy of the light beam of the reproducing head is also changed to To (T
Regeneration may be performed by switching to the energy that becomes o and the energy that becomes Tm ) To ) Tc.

In addition, in the reversible recording area B of the disc 24, as shown in FIG.
), in the same way as the magneto-optical disk explained in (B),
It is possible to erase recorded information and record new information.

Furthermore, when the disk of the present invention is used in an apparatus as shown in FIG. 4, it can also be used in the following manner. For example, if you want to irreversibly record information that has been recorded in a reversible recording area, you can read the information with the reproducing head 32 and send this reproduction signal to the recording head 31 to record the information in the irreversible recording area. . If we develop this method,
It is also possible to first record information in a reversible recording area, read this information with a playback head in a different order from when it was recorded, and re-edit and record it in an irreversible recording area with the recording head.
It is J-Ding Noh.

In the optical information recording/reproducing device described above, when using a disc based on the present invention, for example, it is determined whether the recording area is a reverse recording area or an irreversible recording area based on a change in the amount of reflected light received by a light-receiving confectionery, and the original recording area is automatically recorded. It may also be configured to switch the energy of the beam. Further, the recording area may be determined by providing a light-emitting element and a light-receiving element in the head separately from the recording/reproducing optical system and detecting the difference in reflectance of the recording area.

In addition, the disc of the above embodiment is an example in which the recording materials in the reversible recording area and the irreversible recording area have different degrees of dryness, and the energy of the light beam is controlled to prevent erroneous erasure and erroneous reading/writing in the irreversible recording area. However, each of the recording areas may be made of materials with different sensitivity wavelengths, and recording and reproduction may be performed in each area using light beams with different wavelengths.

In this case, for example, as shown in FIG. 4, the oscillation wavelengths of the laser light sources 40 and 50 are made different, and the recording head 31
A conceivable configuration is to use the recording/reproducing head 32 as a recording/reproducing head for permanent recording and the reproducing head 32 as a recording/reproducing head for magneto-optical recording. In addition, instead of using materials with different sensitivity wavelengths, a reversible recording area and an irreversible recording area are formed on each recording material.
It is also conceivable to form optical thin films with different transmission wavelength ranges.

In the above-mentioned embodiments, the recording in the reversible recording area and the irreversible recording area were bit recording using a low melting point metal and magnetic recording using a magneto-optical material, respectively, but the present invention is not limited to this, and can be applied to other recording areas. Materials can also be used. For example, the reversible recording area can be formed using a material that utilizes phase transition, such as a chalcogen-based or VO-based material whose crystal state changes upon irradiation with light. The irreversible recording area can also be formed using a material 4 that utilizes a change in reflectance, such as an organic dye containing a binder resin or a To-based thin film that causes blackening development.

Of course, the arrangement of the recording areas in the present invention can be modified in various ways, such as, for example, in FIG. 3A, the reversible recording area B is provided at the inner circumference and the irreversible recording area A is provided at the outer circumference. Also, the area ratio of the reversible recording area and irreversible recording area is
It goes without saying that the selection can be made freely during disk production depending on the information to be handled. Further, in the above embodiments, an example of a disc-shaped optical information recording medium was shown, but the present invention can also be applied to optical information recording media of other shapes such as tapes and sheets.

As explained above, the present invention has the effect of making it possible to selectively perform reversible recording and irreversible recording on a single recording medium in a conventional optical information recording medium.

[Brief explanation of the drawing]

FIGS. 1(A) and 1(B) are schematic diagrams illustrating recording on a conventional optical disk, FIGS. 2(A) and 2(B) are schematic diagrams illustrating recording on a conventional magneto-optical disk, respectively, and FIG. (B) is a schematic diagram explaining the present invention in detail, and FIG. 4 is a schematic diagram showing an optical information recording/reproducing apparatus that can use the optical information recording medium of the present invention. 21-11-substrate, 22--1 recording thin film, 23-
--1 Magnetic recording thin film, 24, -Disc, A-111 irreversible recording area, B-1--reversible recording area〇Applicant Canon Co., Ltd. No. 2M (A) No.? Same (B)

Claims (1)

[Claims] (1.) In an optical information recording medium capable of optically recording and reproducing information, a reversible recording area and an irreversible recording area are provided on the same side of the optical information recording medium. An optical information recording medium comprising: (2) The optical information recording medium according to claim 1, wherein the optical information recording medium is disk-shaped, and the reversible recording area and the irreversible recording area are divided concentrically.