JP2000021015A - Optical recording medium and recorder and/or reproducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a recorder and/or a reproducer capable with plural kinds of optical disks with the same system by bringing only reflectance of a medium identification area of plural different kinds of optical disks mutually does to make kinds of the optical disks discriminatable with a laser beam having prescribed same intensity and to perform a recording and reproduction in accordance with the kind of the optical disk. SOLUTION: The reflectance of the medium identification area 12 of an optical disk 1 having weaker reflectance is set higher than that of the signal recording area 11 of the disk 1 by changing optical constants while heating a recording film by irradiating the area 12 with a laser beam having prescribed intensity to perform the reading of information inherent to the disk 1 with the weak laser beam. Thus, the disk information are read out with the same weak laser beam as that in an optical disk having higher reflectance without writing unwanted information in the medium identification area 12 and after respective parameters of the intensity of a laser beam or the like are set to values in accordance with the optical disk whilst an optical head scans a transition are 13, the recording or reproducing of the signal recording area 11 is performed. Moreover, reflectance of both areas 11, 12 can be made to be different by making constitution of the films in the areas differ with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium on which a signal is recorded and / or reproduced by irradiating light, and a signal is recorded on or recorded on the optical recording medium. The present invention relates to a recording and / or reproducing apparatus for reproducing a reproduced signal.

[0002]

2. Description of the Related Art Conventionally, an optical recording system for recording a signal on a recording medium using light or reproducing a signal recorded on the recording medium has been widely used. As a recording medium used in the optical recording system, an optical disk having a signal recording layer formed on a disk-shaped substrate is generally used.

[0003] Optical discs include a ROM type optical disc that can perform only reproduction, a rewritable (RW) optical disc that can perform writing, and a write-once (WO) type that can be rewritten only once. There are optical disks and the like.

[0004] The RW type optical disk includes a magneto-optical (MO) disk for recording signals by magneto-optical recording,
There is a phase change disk or the like that records a signal by phase change recording. In addition, a WO type optical disk is an alloy type disk that records a signal by irradiating a laser beam to alloy a recording layer made of a plurality of layers of metal, and forms a hole in the recording layer by irradiating a laser beam. There are, for example, a perforated disc for recording a signal by recording a signal and a phase change disc for recording a signal by phase change recording.

[0005] These various optical disks generally have an area called a medium identification area on the inner or outer circumference side of a signal recording area, which is an area where actual data such as audio signals and video signals are recorded. Information specific to the disc is recorded in advance in the identification area by using uneven pits.

[0006] A recording and / or reproducing apparatus for recording and / or reproducing signals on these optical discs first reads out the signals recorded in the medium identification area of the loaded optical disc to determine the type of the optical disc. After the recognition, various parameters such as the intensity of the laser beam are set to values corresponding to the optical disc, and a signal is recorded in the signal recording area of the optical disc, or the signal recorded in the signal recording area of the optical disc is reproduced. I am trying to do it. This allows the recording and / or reproducing apparatus to maintain the so-called compatibility of recording and reproducing signals for a plurality of types of optical disks.

[0007]

By the way, in the above-mentioned various optical disks, the reflectivity of the signal recording area is different due to the difference in the recording system and the difference in the film configuration of the signal recording layer. And these optical discs are usually
The signal recording area and the medium identification area are formed of the same film, and the reflectivity of the medium identification area differs for each optical disc.

[0008] For this reason, the following problems have arisen when a single recording and / or reproducing apparatus records and reproduces signals on a plurality of types of optical discs.

That is, if the intensity of the laser beam applied to the medium identification area of the loaded optical disc is set low in accordance with the optical disc having a high reflectivity, the laser light can be reduced when the optical disc having a low reflectivity is mounted. In some cases, information recorded in the medium identification area cannot be read properly because of the low light intensity.

Conversely, if the intensity of the laser beam applied to the medium identification area of the loaded optical disc is set low in correspondence with the optical disc having a low reflectance, when the optical disc having a high reflectance is loaded, In some cases, an unnecessary signal was recorded in the medium identification area due to the high light intensity of the laser light.

In order to solve such inconveniences, it is conceivable to change the film configuration of the signal recording layer of the various optical disks described above so that the reflectivity of each optical disk approaches each other. It is not preferable to make the reflectances of the optical disks close to each other because the degree of freedom in design is greatly restricted.

Accordingly, the present invention provides an optical recording medium from which a signal recorded in a medium identification area by a recording and / or reproducing apparatus corresponding to a plurality of kinds of optical recording media is read out, and a signal for the optical recording medium. It is an object of the present invention to provide a recording and / or reproducing apparatus for performing recording and / or reproduction of the information.

[0013]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, by bringing only the reflectances of the medium identification regions of a plurality of types of optical recording media closer to each other, the signal is obtained. The present inventors have found that a system capable of supporting a plurality of types of optical recording media can be realized without restricting the degree of freedom in film design of the recording area.

The optical recording medium according to the present invention has been created based on such knowledge, and a recording layer formed on a substrate is irradiated with light to record and / or reproduce signals. The optical recording medium includes a signal recording area in which a signal is recorded and a medium identification area in which information for identifying the optical recording medium is recorded, and has a reflectance of the signal recording area and a reflection of the medium identification area. The rates are different from each other.

When the optical recording medium is mounted on a recording and / or reproducing apparatus, first, a laser beam is applied to the medium identification area, and information unique to the optical recording medium is read. Then, a laser beam having an intensity set based on the information unique to the optical recording medium is applied to the signal recording area,
A signal is recorded in the signal recording area, or a signal recorded in the signal recording area is reproduced.

In this optical recording medium, the reflectivity of the medium identification area is made different from the reflectivity of the signal recording area. It can be set to a value close to the rate.

Therefore, by using this optical recording medium, it is possible to realize an optical recording system that records and / or reproduces signals on a plurality of types of optical recording media having different recording systems with one recording and / or reproducing apparatus.

In this optical recording medium, it is desirable that the reflectivity of the medium identification area is set higher than the reflectivity of the signal recording area.

In this optical recording medium, by setting the reflectivity of the medium identification area higher than the reflectivity of the signal recording area, information unique to the optical recording medium can be read by a laser beam of weak intensity. It is.

Therefore, if this optical recording medium is used, it is possible to set the intensity of the laser beam emitted from the recording and / or reproducing apparatus to the medium identification area to be weak, and unnecessary light is not required in the medium identification area. There is no need to worry about writing information.

Further, a recording and / or reproducing apparatus according to the present invention has been devised based on the above-mentioned knowledge, and is for discriminating between a signal recording area in which a signal is recorded and the optical recording medium. A laser beam is applied to an optical recording medium having a medium identification area on which information is recorded, and a signal is recorded on the optical recording medium, or recording and / or reproducing a signal recorded on the optical recording medium is performed. Or, in the reproducing apparatus, after irradiating the medium identification area with laser light having an intensity different from that of the laser light irradiating the signal recording area to identify the type of the optical recording medium, a laser having an intensity corresponding to the type of the optical recording medium It is characterized in that signal recording and / or reproduction are performed by irradiating light to a signal recording area.

In this recording and / or reproducing apparatus, when an optical recording medium is mounted, first, a laser beam having a predetermined intensity is applied to the medium identification area of the mounted optical recording medium, and the medium identification area is illuminated. , Information specific to the loaded optical recording medium is read, and the type of the optical recording medium is recognized.

And, the recording and / or reproducing apparatus comprises:
Based on the information read from the medium identification area, the intensity of the laser light is set to a value corresponding to the mounted optical recording medium. A signal is recorded in a recording area, or a signal recorded in a signal recording area is read.

According to the recording and / or reproducing apparatus, the type of the optical recording medium is identified by irradiating the medium identification area with laser light having an intensity different from the intensity of the laser light applied to the signal recording area. Therefore, the information recorded in the medium identification area can be appropriately read irrespective of the recording method of the optical recording medium, and the signal can be recorded and / or reproduced appropriately.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. Here, an example in which the present invention is applied to a disk-shaped recording medium (hereinafter, referred to as an optical disk) will be described. However, the present invention is not limited to this example. The present invention is also applicable to a recording medium.

As shown in FIG. 1, an optical disk 1 according to the present invention includes a disk substrate 2 formed in a disk shape, and a recording layer 3 on which signals are recorded and a recording layer 3 on the disk substrate 2. And a protective layer 4 for protecting the. The optical disk 1 is irradiated from the disk substrate 2 side, and a laser beam transmitted through the disk substrate 2 is applied to the recording layer 3 to write a signal on the recording layer 3 or write a signal on the recording layer 3. The read signal is read.

The disk substrate 2 is formed by molding a resin material such as polymethyl methacrylate (PMMA) or polycarbonate (PC) into a disk by injection molding.

The recording layer 3 is a layer on which a signal is written or irradiated with a laser beam and from which the written signal is read. A reflection film 6 which is formed on the recording film 5 and functions to increase the efficiency of use of the laser light irradiated on the recording film 5;

The protective layer 4 is for protecting the recording layer 5 and is formed by, for example, spin-coating an ultraviolet curable resin on the recording layer 3.

As shown in FIG. 2, the optical disc 1 has a signal recording area 11 in which actual data such as audio signals and video signals are recorded, and an inner periphery of the signal recording area 11 with a transition area 13 interposed therebetween. And a medium identification area 12 provided on the side.

In the medium identification area 12, the optical disc 1
Is recorded in advance, for example, by emboss pits, wobbling grooves, or the like. And
When the optical disc 1 is mounted on a recording and / or reproducing apparatus, first, information recorded in the medium identification area 12 is read, and its type and the like are identified.

That is, as shown in FIG. 3, when the optical disc 1 is mounted, the recording and / or reproducing apparatus first
The optical disk 1 is rotationally driven to move the optical head to the inner peripheral side of the optical disk 1. Then, the recording and / or reproducing apparatus irradiates a laser beam of a predetermined intensity emitted from the optical head to the medium identification area 12 provided on the inner peripheral side of the optical disc 1 to perform a focus pull-in operation. Do. Next, while performing tracking control as needed, the medium identification area 12 is scanned, and information recorded in the medium identification area 12 is read.

Then, the recording and / or reproducing apparatus identifies the type of the optical disk 1 from the information read from the medium identification area 12, and detects the intensity of the laser light while the optical head scans the transition area 13. Each parameter is set to a value corresponding to the optical disc 1. Then, the recording and / or reproducing apparatus irradiates the signal recording area 11 of the optical disc 1 with laser light in a state corresponding to the optical disc 1, writes a signal in the signal recording area 11, or records a signal recorded in the signal recording area 11. Is read.

In the above, the optical disc 1 in which the medium identification area 12 is provided on the inner peripheral side of the signal recording area 11 with the transition area 13 interposed therebetween has been described, but the present invention is not limited to this example. , On the outer peripheral side of the signal recording area 11,
The medium identification area 12 may be provided with the transition area 13 interposed therebetween. In this case, the recording and / or playback device
The laser beam is irradiated from the outer peripheral side of the optical disc 1.

By the way, in the conventional optical disk, a recording layer having exactly the same configuration is formed in the signal recording area and the medium identification area, and the signal recording area and the medium identification area have the same reflectance. The optical disc 1 according to the present invention is characterized in that the reflectance of the signal recording area 11 and the reflectance of the medium identification area 12 are different from each other. By configuring the optical disc 1 in this manner, an optical recording system that records and / or reproduces signals on a plurality of types of optical discs having different recording systems can be realized by one recording and / or reproducing apparatus.

Hereinafter, a specific method for making the reflectance of the signal recording area 11 different from that of the medium identification area 12 will be described. As described above, the transition area 13 is an area for setting each parameter of the recording and / or reproducing apparatus, and is an area in which no signal is recorded. .

As a method for making the reflectance of the signal recording area 11 different from the reflectance of the medium identification area 12, for example, a method of performing a laser heating process on the medium identification area 12 can be mentioned.

Medium identification area 1 when laser light is irradiated
FIG. 4 shows the state of the reflectance change of No. 2. Here,
The recording layer 3 is composed of a Sb ₂ Se ₃ film having a thickness of 20 to ₃₀ nm, a Bi ₂ Te ₃ film having a thickness of 10 to 20 nm, and a film having a thickness of 100 to 30 nm.
A so-called alloy type comprising a recording film 5 in which a 0 nm Sb ₂ Se ₃ film is laminated in this order and a reflection film 6 made of Al having a thickness of about 100 nm formed on the recording film 5. Optical disk 1 is used.

Then, the optical disk 1 is rotated at a rotation speed of 180.
The medium identification area 1 after rotating at 0 rpm and irradiating the medium identification area 12 with laser light having a wavelength of 680 nm.
The pit modulation degree and reflectance of Sample No. 2 were measured. In FIG. 4, the horizontal axis represents the intensity (DC power) of the laser beam applied to the medium identification area 12, and the vertical axis represents the reflectance and the reproduction amplitude due to the pits. Here, the reflectance of the medium identification area 12 is obtained as a value obtained by converting the amount of return light reflected by the medium identification area 12 into a voltage.

As shown in FIG. 4, the medium identification area 12
In the state where the laser light is not applied to the medium, the medium identification area 12 has a value obtained by converting the amount of reflected light into a voltage of about 175 mV.
The reproduction amplitude by the pit was about 65 mV. And
For example, by irradiating a laser beam having an intensity of 2.5 mW, the value obtained by voltage conversion of the amount of reflected light from the medium identification area 12 increased to about 225 mV, and the reproduction amplitude of the pits increased to about 88 mV. That is, it has been found that, by irradiating the medium identification area 12 with a laser beam having an intensity of 2.5 mW on the optical disc 1, the reflectance and the pit modulation degree of the medium identification area 12 thereafter increase by about 30%.

The increase in the reflectance of the medium identification area 12 is as follows.
The recording film 5 having a three-layer structure as described above is heated and alloyed by irradiation of laser light, and its optical constant (n,
It is considered that this occurred because k) changed. In addition,
The reason that the reflectivity of the medium identification region 12 is increased by the irradiation of the laser beam in this way is not limited to the alloy type optical disc 1 in which the recording film 5 is composed of a plurality of metal films. Similarly, in the case of an optical disk that undergoes a state change by laser light irradiation, such as a phase-change type optical disk that undergoes a phase change, the reflectance also increases.

The optical disc 1 is set so that the reflectance of the medium identification area 12 is higher than the reflectance of the signal recording area 11 in this manner. Information unique to the optical disc 1 is read.

Therefore, if the optical disk 1 set for this purpose is used, the intensity of the laser beam irradiated from the recording and / or reproducing apparatus to the medium identification area 12 can be set to a low value. There is no need to write unnecessary information in the identification area 12.

In the above, an example has been described in which the reflectance of the medium identification region 12 is increased by irradiating the medium identification region 12 with a laser beam. For example, the recording film 5 is formed using an organic dye. By irradiating the medium identification region 12 with laser light, the medium identification region 1
It is also possible to reduce the reflectivity of No. 2.

As a method for making the reflectance of the signal recording area 11 different from the reflectance of the medium identification area 12, for example, the film configuration of the recording layer 3 of the medium identification area 12 may be changed. A method of making the film configuration different from that of the layer 3 may be used.

Specifically, for example, as shown in FIG.
The recording layer 3 of the signal recording area 11 is constituted by the recording film 5 and the reflection film 6, and the recording layer 3 of the medium identification area 12 is constituted only by the reflection film 6. Here, for example, similarly to the above-described example, the recording film 6 is formed of a Sb ₂ Se ₃ film having a thickness of 20 to ₃₀ nm, a Bi ₂ Te ₃ film having a thickness of 10 to 20 nm, and a film having a thickness of 100 nm.
When the reflective film 6 is composed of an Al film having a thickness of about 100 nm, the reflectivity of the signal recording area 11 is about 20% when an Sb ₂ Se ₃ film having a thickness of about 300 nm is laminated in this order. In contrast, the reflectance of the medium identification area 12 is 80%.

As described above, the recording layer 3 of the signal recording area 11
Is composed of the recording film 5 and the reflection film 6, and the medium identification region 1
In order to form the second recording layer 3 only from the reflection film 6, a mask is arranged at a position to be the medium identification area 12 on the disk substrate 2, and after forming each material constituting the recording film 5, the mask is formed. May be removed to form a film constituting the reflection film 6.

In this case, the signal recording area 11
The reflectivity of the recording medium 5 and the reflectivity of the medium identification area 12 can be made different from each other, not limited to the alloy type optical disc 1 in which the recording film 5 is composed of a plurality of metal films. It can be realized in any type of optical disk regardless of the recording method, such as a magneto-optical disk in which the recording film 5 is composed of a magneto-optical recording film, and a phase-change optical disk in which the recording film 5 is composed of a phase-change material. It is.

As a method for making the reflectance of the signal recording area 11 different from the reflectance of the medium identification area 12, for example, the thickness of the recording layer 3 of the medium identification area 12 is determined by changing the thickness of the recording layer of the signal recording area 11. 3 and a method different from the thickness.

[0050] For example, the recording layer 3, as in the example described above, the first film 21 made of Sb ₂ Se _3, and a second layer 22 made of Bi ₂ Te _3, the consisting Sb ₂ Se ₃ 3 membrane 2
3 and a reflective film 6 made of Al formed on the recording film 5 when the recording film 5 is laminated in this order, as shown in FIG. By setting the thickness of the layer 3 to be smaller than the thickness of the signal recording area 11, the reflectance of the medium identification area 12 can be made higher than the reflectance of the signal recording area 11.

In this case, specifically, for example, the thickness of the first film 21 in the medium identification region 12 is
1, the thickness of the first film 21 is set smaller than that of the first film 21 so that the thickness of the entire recording layer 3 in the medium identification area 12 is smaller than the thickness of the recording layer 3 in the signal recording area 11.

The first of the recording film 5 in the medium identification area 12
FIG. 7 shows the relationship between the thickness of the film 21 and the reflectance. In addition,
Here, the thickness of the second film 22 of the recording film 5 is 10 to 20.
nm, the thickness of the third film 23 is set to 100 to 300 nm, and the thickness of the reflection film 6 is set to about 100 nm.
The reflectance of each medium identification area 12 is obtained as a value obtained by voltage-converting the amount of return light reflected by the medium identification area 12. 7, the horizontal axis represents the thickness of the first film 21 of the recording film 5, and the vertical axis represents the value obtained by converting the amount of return light reflected by the medium identification area 12 into a voltage.

As can be seen from FIG. 7, the reflectance of the medium recording area 12 can be increased by reducing the thickness of the first film 21 of the recording film 5 in the medium identification area 12.

For example, the thickness of the first film 21 in the medium identification area 12 is set to about 20 nm, and the signal recording area 11
By setting the film thickness of the first film 21 to about 30 nm, the reflectivity of the medium identification area 12 can be reduced.
1 can be about twice the reflectance.

In contrast to the above example, as shown in FIG. 8, the thickness of the first film 21 in the medium identification area 12 is larger than the thickness of the first film 21 in the signal recording area 11. When the thickness of the entire recording layer 3 in the medium identification area 12 is set to be larger than the thickness of the recording layer 3 in the signal recording area 11, the reflectance of the medium identification area 12 is set to the reflection of the signal recording area 11. Rate can be lower.

As described above, in order to set the film thickness of the first film 21 in the medium identification area 12 and the film thickness of the first film 21 in the signal recording area 11 to different values, the disk substrate 2
When the first film 21 is formed thereon, the film may be formed while controlling the film thickness using a shielding plate at a portion to be the medium identification region 12.

In this case, the signal recording area 11
The reflectivity of the recording medium 5 and the reflectivity of the medium identification area 12 can be made different from each other, not limited to the alloy type optical disc 1 in which the recording film 5 is composed of a plurality of metal films. It can be realized in any type of optical disk regardless of the recording method, such as a magneto-optical disk in which the recording film 5 is composed of a magneto-optical recording film, and a phase-change optical disk in which the recording film 5 is composed of a phase-change material. It is.

As described above, the optical disc 1 according to the present invention has a structure in which the reflectance of the signal recording area 11 and the medium identification area 1
2 are different from each other,
The reflectance of the medium identification area 12 can be set to an arbitrary value irrespective of the reflectance of the signal recording area 11 depending on the recording method or the like. Therefore, if this optical disc 1 is used, it is possible to set the reflectances of the medium identification areas 12 of a plurality of types of optical discs having different recording methods to values close to each other, and to use one recording and / or reproducing apparatus. Thus, it is possible to realize an optical recording system that records and / or reproduces signals on a plurality of types of optical recording media having different recording methods.

Further, in the optical disk 1 according to the present invention, if the reflectance of the medium identification area 12 is set higher than the reflectance of the signal recording area 11, the laser light of low intensity is applied to the optical disk 1 from the medium identification area 12 by a weak laser beam. The unique information can be read out, and the intensity of the laser beam emitted from the recording and / or reproducing apparatus to the medium identification area 12 is set to be low, thereby avoiding the inconvenience of writing unnecessary information to the medium identification area 12. be able to.

[0060]

According to the optical recording medium of the present invention, the reflectivity of the medium identification area is made different from the reflectivity of the signal recording area. It can be set to a value close to the reflectance of the optical recording medium.

Therefore, by using this optical recording medium, it is possible to realize an optical recording system that records and / or reproduces signals on a plurality of types of optical recording media having different recording systems with one recording and / or reproducing apparatus.

Further, the recording and / or reproducing apparatus according to the present invention irradiates the medium identification area with laser light having an intensity different from that of the laser light applied to the signal recording area to identify the type of the optical recording medium. Since the signal recording area is irradiated with a laser beam having an intensity corresponding to the type of the optical recording medium to record and / or reproduce the signal, the medium can be identified independently of the recording method of the optical recording medium. Information recorded in the area can be appropriately read, and signal recording and / or reproduction can be appropriately performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an example of an optical disk according to the present invention.

FIG. 2 is a plan view of the optical disc.

FIG. 3 is a diagram for explaining an operation of the recording and / or reproducing apparatus according to the present invention at the time of activation.

FIG. 4 is a diagram illustrating the relationship between the intensity of laser light applied to a medium identification area and the reflectance of the medium identification area after the laser light is applied.

FIG. 5 is a sectional view of a main part showing another example of the optical disc according to the present invention.

FIG. 6 is a sectional view of a main part showing still another example of the optical disk according to the present invention.

FIG. 7 is a diagram for explaining the relationship between the thickness of a first film constituting the recording film and the reflectance.

FIG. 8 is a sectional view of a main part showing still another example of the optical disc according to the present invention.

[Explanation of symbols]

1 optical disk, 2 disk substrate, 3 recording layer, 4
Protective layer, 5 recording film, 6 reflective film, 11 signal recording area, 12 medium identification area, 21 first film

Claims (6)

[Claims] 1. An optical recording medium in which a recording layer formed on a substrate is irradiated with light to record and / or reproduce a signal, wherein a signal recording area where a signal is recorded is identified from the optical recording medium. An optical recording medium, comprising: a medium identification area on which information for recording is recorded, wherein a reflectance of the signal recording area and a reflectance of the medium identification area are different from each other. 2. The optical recording medium according to claim 1, wherein the medium identification area is an area in which the recording layer is subjected to a laser heating process and has a reflectance different from that of the signal recording area. 3. The medium identification area is an area having a reflectance different from that of the signal recording area because the film configuration of the recording layer is different from the film configuration of the recording layer of the signal recording area. The optical recording medium according to claim 1, wherein 4. The medium identification area is an area having a reflectance different from that of the signal recording area because the thickness of the recording layer is different from the thickness of the recording layer of the signal recording area. The optical recording medium according to claim 1. 5. The optical recording medium according to claim 1, wherein the reflectance of the medium identification area is higher than the reflectance of the signal recording area. 6. An optical recording medium having a signal recording area in which a signal is recorded and a medium identification area in which information for identifying the optical recording medium is recorded is irradiated with laser light. In a recording and / or reproducing apparatus which records a signal on a recording medium or reproduces a signal recorded on the optical recording medium, the medium identifying a laser beam having an intensity different from that of the laser beam applied to the signal recording area. After irradiating an area to identify the type of the optical recording medium, the signal recording area is irradiated with a laser beam having an intensity corresponding to the type of the optical recording medium to record and / or reproduce a signal. Recording and / or reproducing apparatus.