JPH02285532A - Optical recording medium and recording method using the same - Google Patents

Abstract

PURPOSE:To detect the degradation of a recorded layer caused by reloading as early as possible and to avoid the worst that information are lost by providing a part, for which durability to the repetition of recording and erasing is weaker than the other part, in one part of each prescribed information unit. CONSTITUTION:Between an address part 11 and a data part 12 of a sector 1, an indicator signal recording part 13 is provided and width between lands 21 and 22 of the indicator signal recording part 13 is made narrow. Then, the indicator signal recording part 13 is formed so that a recording mark S of an indicator signal can cover a boundary between the land 21 or 22 and a group 3. As a result, a step is provided for the recording mark and in comparison with the flat mark of the other address part and data part, damage caused by thermal shock is received more easily. Thus, since the degradation of the recorded layer caused by the reloading can be detected as early as possible, the state that the information are lost can be prevented in advance.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical recording medium and an optical recording medium using the same. The present invention relates to an optical recording medium in which the degree of deterioration of the optical recording medium due to repeated operations can be easily detected, and a recording method using the same.

[Conventional technology]

In recent years, rewritable optical recording media have been actively developed. As a representative example.

Examples include phase-change optical disks and magneto-optical disks that use materials that undergo reversible phase transformation. Other proposals include bubble recording type (the recording state is when a bubble is formed, and the erased state is when the bubble is flattened after being melted by an erasing beam), and one using photochromic materials. has been done.

When recording information on these optical recording media, the information is recorded in appropriate units, that is, predetermined information units (hereinafter sometimes referred to as "sectors"), and the information is rewritten for each sector. is common.

[Problem to be solved by the invention]

However, when an optical recording medium is used for a long period of time, differences inevitably arise between sectors, such as sectors that are rewritten more frequently and sectors that are rewritten less frequently. Even with rewritable optical recording media, it cannot be said that there will be no deterioration due to rewriting operations (erasing and rewriting information), and it is inevitable that signal deterioration will occur, albeit gradually, after being rewritten many times. .

As a result, especially in sectors that are frequently rewritten, there is a risk that important information will eventually be lost due to deterioration.

The present invention detects deterioration of the recording layer due to rewriting at an early stage,
The object of the present invention is to provide an optical recording medium and a recording method using the optical recording medium that can avoid the worst case of losing information.

[Means to solve the problem]

One aspect of the present invention is to reversibly cause a state change by irradiation with a light beam, and record, erase, and reproduce information by optically detecting the change, and to record, erase, and reproduce information. An optical recording medium capable of performing data recording for each predetermined information unit, characterized in that a portion of each predetermined information unit has a portion that is less resistant to repeated recording and erasing than other portions. There is.

Another aspect of the present invention is that when recording and erasing information using the optical recording medium, recording and erasing is performed simultaneously with other parts of the sector including the part with weak resistance. The feature is that the deterioration of the medium due to repeated recording and erasing of the sector can be detected from the degree of deterioration in the portion with weak resistance.

By the way, the inventor of the present invention aimed to detect the danger of optical recording media as described above (that is, there is a risk that the frequency of rewriting will exceed the limit and eventually lose important information). As a result of many studies, we have found that some parts of a sector are more likely to be damaged by repeated recording and erasing than others. We confirmed that this can be achieved by intentionally creating areas that are easy to receive. The present invention has been achieved thereby.

The present invention will be explained in more detail below using a rewritable phase change optical disc as an example.

In this type of optical disk, information is generally recorded by setting the recording material in a crystalline state to an unrecorded state, and then rapidly heating and cooling it by irradiation with a recording beam to form marks (recording marks) in an amorphous state. During erasing, the recording mark is irradiated with an erasing beam of lower power than the recording beam, and the mark is crystallized by rapid heating and slow cooling.

In particular, during recording, it is necessary to heat the recording material to a temperature below its melting point and then rapidly cool it, and to prevent the film from deforming while in the molten state, the recording layer is usually made of SiO□, ZnS, etc. It is sandwiched from the top and bottom by a sturdy protective layer.

Nevertheless, during the recording and erasing processes, the recording layer is subjected to considerable thermal shock and is gradually damaged by local stress caused by rapid heating.

The main cause of damage is physical deformation of the recording layer and/or the protective layer (especially the protective layer).Therefore, although more robust protective layer materials have been actively developed in recent years, there is no damage at all. No protective layer material has yet been found that does not.

Now, in FIG. 1, between the address part 11 and data part 12 of sector 1, these address part 11 and data part 12
This shows a state in which a portion 13 is provided that is more susceptible to damage due to repeated recording and erasing. The location of this part 13 is not necessarily the same as that of address part 11 and data part 1.
For example, within sector 1 and at the beginning (before address section 11).
, in the data section 12, within sector l and at the end thereof,
It does not matter where it is provided as long as it is within sector 1.

An appropriate signal (hereinafter referred to as "U indicator signal") is applied to the partial work 3, which is a part of this sector 1 and is more susceptible to damage due to repeated recording and erasing than the other parts 11 and 12.
) shall be recorded. Therefore, in the following description, the portion indicated by the reference numeral 13 will be referred to as the "indicator signal recording section."

The indicator signal recording section 13 may take any form as long as it has a structure that is more susceptible to damage due to repeated recording and erasing than the address section 11 and the data section 12. For example, in addition to the land recording method mentioned in the embodiment described later, a method may be adopted in which the thickness of the protective layer of the indicator signal recording section 13 is made thinner, or the thickness described is made thicker or thinner. . These film thickness controls can be performed by appropriate mask operations, etching operations, etc. during film formation.

When rewriting the contents of a sector, the indicator signal is also subjected to the same erasing and rewriting process.

The indicator signal to be re-recorded may be the same as or different from the one before erasing. The indicator signal is the most susceptible to deterioration during repeated rewriting, so the signal level or signal pattern of the indicator signal should be monitored each time it is rewritten, and the degree of deterioration can be determined to prevent the original data from deteriorating. Data is protected by adopting an algorithm such as prohibiting rewriting of sector 1.

So far, as mentioned above, the phase change optical disk has been described, but it goes without saying that similar means can be applied to magneto-optical disks and other rewritable media.

Furthermore, in Japanese Patent Application Laid-open No. 1197748/1983, a second transparent layer is provided on a first transparent layer that is transparent to light of a specific wavelength, and a signal is formed on the second transparent layer as a surface deformation. An optical recording medium is described in which a reflective layer is provided on a surface having a deformation. However, although this optical recording medium has the advantage that a signal from an external information source can be written directly onto the recording film on the medium as a perforated bit string, it has not been devised at all as intended by the present invention.

Further, Japanese Patent Application Laid-Open No. 63-300435 describes an optical recording medium in which the absorption efficiency of the erasing beam in the recording layer is selectively varied at specific locations in the circumferential direction. However, the "specific position" mentioned here refers to the sector mark (address) part, and in order to prevent the address part from being destroyed by repeated recording and erasing, the light absorption rate of the address part is lower than that of other parts. Therefore, consideration has been made to actively provide durability to the address section, and it is expected that the optical recording medium will be used for a long period of time. The point of view is fundamentally different from that of the present.

〔Example〕

Here, as shown in FIG. 1, an indicator signal recording section 13 is provided between the address section 11 and the data section 12 of sector 1, and so-called land recording is adopted. That is, as shown in FIG. 2(a), the widths of the lands 21 and 22 of the indicator signal recording section 13 are narrowed, and the indicator signal recorder S (encircled by a broken line) is located at the land 2.
It is formed so as to cover the boundary between group 1 or 22 and group 3. As a result, the recording mark has a step, as shown in FIG. 2(b), and is more susceptible to damage from heat stains than other flat marks in the address and data areas.

Note that the optical recording medium used here has ZnS71 (base layer) of about 2000 octane on a polycarbonate molded substrate 4.
5, about 1000 Gez 25b2Z Te, 6
An alloy layer (recording layer) 6 and about 2000 Zn5W (protection 7fl) 7 were sequentially deposited by sputtering.

When the same sector was repeatedly rewritten in this optical recording medium, deterioration of the indicator signal was observed after approximately 200,000 rewrites. At this point, there was no deterioration of the data section at all, and its function as an indicator was confirmed.

[Effects of the Invention] According to the optical recording medium of the present invention and the recording method using the same, deterioration of the recording layer due to rewriting can be detected early, so that a situation such as information loss can be prevented in advance.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one sector of an optical recording medium according to the present invention. FIG. 2(a) is an enlarged view of the vicinity of the indicator signal recording section, and FIG. 2(b) is a sectional view of the vicinity of the broken line shown in FIG. 2(Ca). 1...Sector 11...Address section 12...Data section 13...Indicator signal recording section 21,22...
・Land 3...Group 4...Substrate 5...Underlying layer 6...Recording layer 7...Protective layer Patent applicant Rico Co., Ltd.

Claims (2)

[Claims] (1) Reversible state change caused by irradiation with a light beam,
In an optical recording medium capable of recording, erasing, and reproducing information by optically detecting the change, and recording and erasing information in units of predetermined information units, each predetermined An optical recording medium characterized by having a portion within an information unit that is less resistant to repeated recording and erasing than other portions. (2) Causes a reversible state change by irradiation with a light beam,
It is possible to record, erase, and reproduce information by optically detecting the change, and to record and erase information for each predetermined information unit. When recording and erasing information using an optical recording medium that has some parts that are less resistant to repeated recording and erasing than other parts, it is necessary to Recording and erasing operations are performed in the same manner as other parts of a predetermined information unit, including the information unit, and deterioration of the medium due to repeated recording and erasure of the predetermined information unit can be detected from the degree of deterioration in the parts with weaker resistance. An optical recording method characterized by: