JP4136882B2 - Optical recording medium - Google Patents

Description

  The present invention relates to a write-once optical recording medium. More specifically, the present invention can provide a reproduction signal having good signal characteristics while preventing an increase in manufacturing cost, and can provide reliability for long-term storage. The present invention relates to an optical recording medium that can be enhanced.

  Conventionally, as a recording medium for recording digital data, an optical recording medium represented by a CD or a DVD has been widely used, and in recent years, it is a next generation type having a larger capacity and a higher data transfer rate. Development of optical recording media has been actively conducted.

  These optical recording media are ROM-type optical recording media of a type in which data cannot be added or rewritten, such as CD-ROM or DVD-ROM, and data can be additionally written, such as CD-R or DVD-R. However, it can be roughly divided into a write-once type optical recording medium of a type in which data cannot be rewritten and a rewritable type optical recording medium of a type in which data can be rewritten, such as CD-RW and DVD-RW. it can.

  As is well known, in a ROM type optical recording medium, data is generally recorded by prepits formed on a substrate in the manufacturing stage. In a rewritable type optical recording medium, For example, a phase change material is used as the recording layer material, and data is generally recorded by utilizing a change in optical characteristics based on a change in the phase state.

  In the write-once type optical recording medium, organic materials such as cyanine dyes, phthalocyanine dyes, and azo dyes are used as the recording layer material, and the chemical change, physical change, or both of them are used. It is common for data to be recorded using changes in optical properties based on it.

  However, the organic dye may be deteriorated by irradiation with sunlight or the like, and when the organic dye is used as the recording layer material, it is not easy to improve the reliability for long-term storage. Therefore, in order to increase the reliability for long-term storage, it is required to use materials other than organic dyes for the recording layer of the write-once type optical recording medium. In order to meet this demand, what is described in Patent Document 1 is known as an example in which the recording layer is made of a material other than an organic dye.

In the write-once type optical recording medium described in the same patent document, two inorganic material layers are laminated to form a recording layer, and the two inorganic material layers are formed as main components by irradiating a laser beam. The elements contained are mixed, and eutectic crystallization is caused in this mixing process. In this way, when the materials of the inorganic material layer laminated in two layers are mixed and eutectic crystallized, the optical characteristics are different between the eutectic crystallized region and the other regions. Can be used to record data.
JP 62-204442 A

  However, in the write-once type optical recording medium described in Patent Document 1, two inorganic material layers are stacked, and data is recorded by using a mixture of these two inorganic material layers. Therefore, two layers are required to form one recording layer, and there is a problem that the manufacturing cost of the optical recording medium increases.

  Further, in the write-once type optical recording medium described in the patent document, there is a difference in optical characteristics between a recording mark formed by mixing two eutectic material layers and eutectic crystallization and other regions. Since it is not so large, there is also a problem that it is difficult to record data so that a reproduction signal having good signal characteristics can be obtained.

  Especially for next-generation optical recording media that can increase the data recording density and achieve a very high data transfer rate, the beam spot diameter of the laser beam used for data recording and reproduction is extremely high. Since it is required to narrow down and the difference between the recording mark and the optical characteristics of the area other than the recording mark is sufficiently large, it is extremely possible to obtain a reproduction signal having a good C / N ratio. It was difficult.

  On the other hand, since such optical recording media may be stored for a long period of time in an actual usage environment, the characteristics of the recording layer may be altered so that the reproduction characteristics do not deteriorate. It is necessary that the data recorded on the recording layer does not deteriorate and has high reliability for long-term storage.

  Therefore, the present invention provides an optical recording medium capable of obtaining a reproduction signal having good signal characteristics while preventing an increase in manufacturing cost and improving reliability for long-term storage. It is intended.

The object of the present invention includes a first waterproof layer, a second waterproof layer, and a recording layer formed between the first waterproof layer and the second waterproof layer . At least one of the waterproof layer and the second waterproof layer is formed adjacent to the recording layer, and the recording layer is formed of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, By irradiating a recording laser beam with at least one elemental metal element M selected from the group consisting of W, Pb, Bi, Zn, and La, the metal element M is combined with the element to form the metal element. S or O-containing Mutotomoni to produce crystals of the compound of M, further, Mg, at least one metallic element selected from the group consisting of Al and Ti, when containing Mg, the content of Mg is 18.5 atom % To 42 atom% When containing Al, as the Al content is 70 atomic% to 11 atomic% to, when containing Ti is seen containing as the content of Ti is 8 atomic% to 38 atomic%, the recording layer A waterproof layer formed adjacently includes a dielectric material as a main component, and when a recording laser beam is irradiated, a recording mark having a reflectance different from that of other regions is formed on the recording layer. And at least a part of the region of the at least one waterproof layer in contact with the recording mark is crystallized to form a crystallized region .

  In the present invention, the optical recording medium includes a first waterproof layer, a second waterproof layer, and a recording layer formed between the first waterproof layer and the second waterproof layer.

In the present invention, the recording layer is made of at least one metal element M selected from the group consisting of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and La. A single element and S or O that forms a crystal of a compound with the metal element M by being irradiated with a recording laser beam to combine with the single element of the metal element M; and Mg, Al, and Ti And at least one metal element selected from the group consisting of:

  Since the recording layer formed to have such a composition is composed of a single recording film formed of an inorganic material, the characteristics of the recording layer may be altered or recorded on the recording layer by irradiation with sunlight or the like. It is possible to prevent the recorded data from deteriorating and to reduce the manufacturing cost of the optical recording medium.

Further, in the present invention, the recording layer containing a metal element M and S, or O can be irradiated recording laser beam, when the data is recorded, a metal element M and S or O are combined in the compound Data is recorded by generating crystals.

Thus, when data is recorded, in the reflectance of the recording layer with respect to the laser beam, the difference in reflectance between the region where the compound of the metal element M and S or O is crystallized and the other region is increased. Therefore, according to the present invention, it is possible to obtain a reproduced signal having good signal characteristics.
Here, when the recording layer contains a 7B group element such as F or Cl, the reactivity is too high, so that it reacts with the metal element M without irradiating the recording laser beam, Further, when the recording layer contains a 5B group element such as N or P, the reactivity is too weak to react with the metal element M, and the recording sensitivity may be deteriorated.
On the other hand, when the recording layer contains O or S which is a group 6B, the reaction positive is neither too high nor too weak, and it is reacted with the metal element M as desired. Can occur.
In the present invention, when the recording layer contains Mg, the Mg content is preferably 18.5 atomic percent to 42 atomic percent, more preferably 20 atomic percent to 37 atomic percent, and Al When Al is included, the Al content is preferably 11 atomic% to 70 atomic%, more preferably 18 atomic% to 56 atomic%, and when Ti is included, the Ti content is 8 atomic% to 38 atomic% is preferable, and 10 atomic% to 36 atomic% is more preferable.

  Furthermore, in the present invention, the recording layer is formed between the first waterproof layer and the second waterproof layer.

  In the present invention, both the first waterproof layer and the second waterproof layer serve to prevent moisture from entering the recording layer.

  Therefore, according to the present invention, the first waterproof layer and the second waterproof layer can prevent moisture from entering the recording layer, so that erosion of the recording layer due to moisture can be prevented. Thus, the reliability of the optical recording medium for long-term storage can be further enhanced.

In the present invention, the first waterproof layer and the second waterproof layer at least one, it is formed adjacent to the recording layer.

  When at least one of the first waterproof layer and the second waterproof layer is formed adjacent to the recording layer, it is effective to prevent moisture from entering the recording layer via the side surface of the optical recording medium. The reliability of the optical recording medium for long-term storage can be further increased.

  Further, in the present invention, the waterproof layer formed adjacent to the recording layer contains a dielectric material as a main component, and when the recording laser beam is irradiated, the recording layer has another region. And a recording mark having a different reflectance is formed, and at least a part of a region in contact with the recording mark of the at least one dielectric layer is crystallized to form a crystallized region. .

  In the present invention, at the same time that the recording mark is formed on the recording layer, at least a part of the waterproof layer in contact with the recording mark is crystallized to form a crystallized region. The difference between the reflectivity of the region where the recording mark and the crystallized region are formed and the reflectivity of other regions can be increased as a whole, and thus a reproduced signal having even better signal characteristics can be obtained. It becomes possible.

  In a further preferred embodiment of the present invention, the recording layer is configured to record data using a laser beam having a wavelength of 380 nm to 450 nm and to reproduce the recorded data.

  Since such a recording layer exhibits good optical characteristics with respect to a laser beam having a wavelength of 380 nm to 450 nm, data is recorded using the laser beam having a wavelength of 380 nm to 450 nm, and the recorded data is reproduced. It is preferable.

  According to the present invention, an optical recording medium capable of obtaining a reproduction signal having good signal characteristics while preventing an increase in manufacturing cost and improving reliability for long-term storage, and a method for manufacturing the same. Can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view of an optical recording medium 10 according to a preferred embodiment of the present invention, and FIG. 2 is a schematic enlarged view of a portion indicated by A in FIG.

  As shown in FIG. 1, the optical recording medium 10 according to the present embodiment is formed in a disc shape having an outer diameter of about 120 mm and a thickness of 1.2 mm. As shown in FIG. The support substrate 11, the first waterproof layer 12, the first transparent intermediate layer 13, the recording layer 14, the second transparent intermediate layer 15, the second waterproof layer 16, and the light transmission layer 17 It has.

  The support substrate 11 functions as a support for ensuring the mechanical strength required for the optical recording medium 10.

  The material for forming the support substrate 11 is not particularly limited as long as it can function as a support for the optical recording medium 10. The support substrate 11 can be formed of glass, ceramics, resin, or the like, for example. Of these, a resin is preferably used from the viewpoint of ease of molding. Examples of such resins include polycarbonate resins, acrylic resins, epoxy resins, polystyrene resins, polyethylene resins, polypropylene resins, silicone resins, fluorine resins, ABS resins, and urethane resins. Among these, polycarbonate resin is particularly preferable from the viewpoint of processability and optical characteristics, and in this embodiment, the support substrate 11 is formed of polycarbonate resin. In this embodiment, since the laser beam L is irradiated through the light incident surface 17a located on the opposite side to the support substrate 11, it is necessary that the support substrate 11 has light transmittance. Not.

  In this embodiment, the support substrate 11 has a thickness of about 1.1 mm.

  As shown in FIG. 2, a first waterproof layer 12 is formed on the surface of the support substrate 11.

  The first waterproof layer 12 serves to prevent moisture from entering the recording layer 14 described later via the support substrate 11 from the outside of the optical recording medium 10.

In the present embodiment, the material for forming the first waterproof layer 12 is not particularly limited as long as moisture can be prevented from entering the recording layer 14, and Ni, Ge, Nb, Mo, At least one selected from the group consisting of In, W, Bi, La, Si, Zn, Al, Ta, Ti, Co, Zr, Pb, Ag, Zn, Sn, Ca, Ce, V, Cu, Fe, and Mg Dielectric materials composed of metal-containing oxides, nitrides, sulfides, fluorides, or composites thereof, and resin materials having waterproofness (low water absorption) such as polystyrene, polyolefin and vinylidene chloride The first waterproof layer 12 is preferably used to form the first waterproof layer 12. For example, it is particularly preferable to form the first waterproof layer 12 with a material mainly composed of a dielectric made of ZnS · SiO _2. Good.

Here, in this specification, including an element as a main component means that the content of the element is 50 atomic% to 100 atomic%, and ZnS · SiO ₂ is a mixture of ZnS and SiO ₂ . Means.

  The first waterproof layer 12 can be formed on the surface of the support substrate 11 by, for example, a vapor phase growth method using the constituent elements of the first waterproof layer 12. Examples of the vapor deposition method include a vacuum deposition method and a sputtering method.

  When the first waterproof layer 12 is formed so as to contain a dielectric material as a main component, the first waterproof layer 12 is preferably formed to have a thickness of 20 nm to 150 nm, and has a thickness of 30 nm to 120 nm. More preferably, it is formed as follows.

  When the thickness of the first waterproof layer 12 is less than 20 nm, the waterproof property required for the first waterproof layer 12 cannot be satisfied. May get worse.

  As shown in FIG. 2, a first transparent intermediate layer 13 is formed on the surface of the first waterproof layer 12.

  The first transparent intermediate layer 13 serves to separate the first waterproof layer 12 and the recording layer 14 from each other. When the substance contained in the recording layer 14 reacts with the substance contained in the first waterproof layer 12 to cause a problem, the problem is prevented by separating the recording layer 14 and the first waterproof layer 12. be able to.

  The material for forming the first transparent intermediate layer 13 is not particularly limited, but it is preferable to use an ultraviolet curable acrylic resin.

  The first transparent intermediate layer 13 is preferably formed to have a thickness of 2 μm to 50 μm, and more preferably 5 μm to 30 μm.

  As shown in FIG. 2, grooves 13 a and lands 13 b are alternately formed on the surface of the first transparent intermediate layer 13. The grooves 13a and / or lands 13b formed on the surface of the first transparent intermediate layer 13 function as a guide track for the laser beam L when data is recorded on and reproduced from the recording layer 14. .

  The depth of the groove 13a is not particularly limited, but is preferably set to 10 nm to 40 nm, and the pitch of the groove 13a is not particularly limited, but is set to 0.2 μm to 0.4 μm. It is preferable to do.

  As shown in FIG. 2, a recording layer 14 is formed on the surface of the first transparent intermediate layer 13.

  The recording layer 14 is a recording layer for recording data, and is composed of a single recording film.

  In this embodiment, the recording layer 14 includes at least one metal element selected from the group consisting of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and La. And an element of S or O.

  The recording layer 14 preferably has a thickness of 8 nm to 60 nm, and more preferably has a thickness of 10 nm to 45 nm.

  When the thickness of the recording layer 14 is less than 8 nm, the C / N ratio of the reproduction signal when the data recorded on the recording layer 14 is reproduced becomes insufficient. On the other hand, when the thickness of the recording layer 14 exceeds 60 nm. This is not preferable because the film formation time becomes long and the productivity may be deteriorated.

  Thus, according to this embodiment, the recording layer 14 is at least selected from the group consisting of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and La. Since it is composed of a single recording film containing a kind of metal element and an element of S or O and using an inorganic material, the characteristics of the recording layer 14 may be altered by irradiation with sunlight or the like. 14 can be prevented from being deteriorated, and the manufacturing cost of the optical recording medium can be reduced.

  As shown in FIG. 2, a second transparent intermediate layer 15 is formed on the surface of the recording layer 14.

  The second transparent intermediate layer 15 serves to separate the recording layer 14 from a second waterproof layer 16 described later. The substance contained in the recording layer 14 reacts with the substance contained in the second waterproof layer 16 in the same manner as the recording layer 14 and the first waterproof layer 12 are separated by the first transparent intermediate layer 13. If a problem occurs, the problem can be prevented by separating the recording layer 14 and the second waterproof layer 16 from each other.

  As with the first transparent intermediate layer 13, it is preferable to use an ultraviolet curable acrylic resin for the second transparent intermediate layer 15.

  The second transparent intermediate layer 15 is preferably formed to have a thickness of 3 μm to 150 μm, more preferably 5 μm to 95 μm.

  As shown in FIG. 2, a second waterproof layer 16 is formed on the surface of the second transparent intermediate layer 15.

  The second waterproof layer 16 serves to prevent moisture from entering the recording layer 14 from the outside of the optical recording medium 10 via the light transmission layer 17.

  The material for forming the second waterproof layer 16 is not particularly limited as long as moisture can be prevented from entering the recording layer 14, and the same material as the first waterproof layer 12 is used. The second waterproof layer 16 can be formed.

  The second waterproof layer 16 and the second waterproof layer 12 may be formed of the same dielectric material or resin material, but may be formed of different dielectric materials or resin materials.

  The second waterproof layer 16 is preferably formed to have a thickness of 20 nm to 150 nm, more preferably 30 nm to 120 nm, when the dielectric layer is formed mainly of a dielectric material. Formed to have.

  When the thickness of the second waterproof layer 16 is less than 20 nm, the waterproof property required for the second waterproof layer 16 cannot be satisfied, and when it exceeds 150 nm, the film formation time becomes long, and the productivity is increased. May get worse.

  The second waterproof layer 16 is a layer through which the laser beam L is transmitted when data is recorded on the recording layer 14 or when data recorded on the recording layer 14 is reproduced. It must be permeable.

  As shown in FIG. 2, a light transmission layer 17 is formed on the surface of the second waterproof layer 16.

  The light transmission layer 17 is a layer that transmits a laser beam, and one surface thereof forms a light incident surface 17a.

  The material for forming the light transmission layer 17 is not particularly limited, but it is preferable to use an acrylic or epoxy ultraviolet curable acrylic resin.

  The light transmission layer 17 needs to have a sufficiently high light transmittance because the laser beam L passes through when recording and reproducing data.

  When the second waterproof layer 16 is formed apart from the recording layer 14, the light transmission layer 17 is preferably formed to have a thickness of 1 μm to 15 μm, and a thickness of 3 μm to 12 μm. More preferably, it is formed to have a thickness.

  The optical recording medium 10 having the above configuration is manufactured as follows.

  First, the support substrate 11 is formed by injection molding.

  Next, the first waterproof layer 12 is formed on the surface of the support substrate 11 by a vapor phase growth method using chemical species including the constituent elements of the first waterproof layer 12. Examples of the vapor deposition method include a vacuum deposition method and a sputtering method.

  Next, an ultraviolet curable acrylic resin is applied onto the surface of the first waterproof layer 12 by a spin coating method to form a coating film, and the stamper is put on the surface of the coating film via a stamper. By irradiating with ultraviolet rays, the first transparent intermediate layer 13 having the grooves 13a and lands 13b formed on the surface is formed.

  Next, the recording layer 14 is formed on the surface of the first transparent intermediate layer 13. Here, the recording layer 14 is a simple substance of at least one metal element selected from the group consisting of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and La. Of these, a case where the metal element is formed so as to include a single metal element of Zn or La will be described as an example.

On the surface of the first transparent intermediate layer 13, and a target containing ZnS · SiO ₂ or La · Si · O · N as a main component, Mg, at least one metallic element selected from the group consisting of Al and Ti main The recording layer 14 is formed by sputtering using a target that is included as a component.

Thus, using a target containing ZnS · SiO ₂ or La · Si · O · N as a main component and a target containing at least one metal element selected from the group consisting of Mg, Al and Ti as a main component, When the recording layer 14 is formed by sputtering, at least one metal element selected from the group consisting of Mg, Al, and Ti acts as a reducing material in the film formation process of the recording layer 14, and as a result, the recording layer 14, the metal element of Zn or La exists in a single form.

Specifically, for example, when a target containing ZnS · SiO ₂ as a main component and a target containing Mg as a main component are used as targets, Mg is a reducing agent for ZnS contained in ZnS · SiO _2. As a result, Zn is uniformly dispersed in the recording layer 14. At this time, Mg used as the reducing agent is separated from ZnS or bonded to a part of S contained in ZnS to form MgS. Therefore, Zn is contained in the recording layer 14 in a single form.

In this embodiment, when the recording layer 14 contains ZnS · SiO ₂ as a main component, the molar ratio of ZnS to SiO ₂ in the recording layer 14 is preferably 40:60 to 80:20, and 65 : 35 to 75:25 is more preferable.

When the ZnS molar ratio is 40% or more, both the reflectance and light transmittance of the recording layer 14 with respect to the laser beam can be improved, and when the ZnS molar ratio is 80% or less. Can reliably prevent the recording layer 14 from cracking due to stress. Furthermore, if the molar ratio of ZnS to SiO ₂ is set to 65:35 to 75:25, the reflectance of the recording layer 14 with respect to the laser beam can be more effectively prevented while cracking occurs in the recording layer 14. And the light transmittance can be further improved.

Further, in this embodiment, when the recording layer 14, including a sputtering target, the La · Si · O · N as main components, _SiO 2, _Si 3 _{N 4} constituting the La · Si · O · N And La ₂ O ₃ , the molar ratio of SiO ₂ to the sum of Si ₃ N ₄ and La ₂ O ₃ is preferably 10:90 to 50:50, and SiO ₂ , Si ₃ N ₄ and La ₂ More preferably, the molar ratio of O ₃ is 30:50:20.

When the molar ratio of SiO ₂ is less than 10%, the recording layer 14 tends to crack, and when the molar ratio of SiO ₂ exceeds 50%, the reflection of the recording layer 14 is reduced due to a decrease in refractive index. If the molar ratio of the sum of Si ₃ N ₄ and La ₂ O ₃ is 50% to 90%, a high refractive index can be obtained and cracking can be prevented. Because it can. Considering these, it is more preferable that the molar ratio of SiO ₂ , Si ₃ N ₄ and La ₂ O ₃ is 30:50:20 as a sputtering target.

  Furthermore, in this embodiment, when the recording layer 14 contains Mg, the Mg content is preferably 18.5 atomic% to 42 atomic%, and preferably 20 atomic% to 37 atomic%. More preferably, when Al is contained, the content of Al is preferably 11 atomic% to 70 atomic%, more preferably 18 atomic% to 56 atomic%, and when Ti is contained, The content of is preferably 8 atomic% to 38 atomic%, more preferably 10 atomic% to 36 atomic%.

  Next, an ultraviolet curable acrylic resin is applied on the surface of the recording layer 14 by a spin coating method to form a coating film, and the second transparent intermediate layer 15 is formed by irradiating with ultraviolet rays.

  Next, the second waterproof layer 16 is formed on the surface of the second transparent intermediate layer 15 by a vapor phase growth method using chemical species including the constituent elements of the second waterproof layer 16. Examples of the vapor deposition method include a vacuum deposition method and a sputtering method.

  Then, an ultraviolet curable acrylic resin is applied on the surface of the second waterproof layer 16 by a spin coating method to form a coating film, and the coating film is irradiated with ultraviolet rays to form a light transmission layer 17. To do.

  Thus, the optical recording medium 10 is manufactured.

  As described above, according to this embodiment, the first waterproof layer 12 is provided between the support substrate 11 and the recording layer 14, and the second waterproof layer 17 and the recording layer 14 are provided between the second transparent layer 17 and the recording layer 14. Since the waterproof layer 16 is provided, it is possible to prevent moisture from entering the recording layer 14 from the outside of the optical recording medium 10 via the support substrate 11 or the light transmission layer 17. The erosion of the layer 14 can be avoided, and therefore the reliability of the optical recording medium for long-term storage can be further enhanced.

  Data is recorded on the optical recording medium 10 according to the present embodiment configured as described above as follows.

  In this embodiment, when recording data on the optical recording medium 10, a laser beam L having a wavelength λ of 380 nm to 450 nm is irradiated through the light incident surface 17 a of the light transmission layer 17, and the recording layer 14 is The laser beam L is focused.

  FIG. 3 is a diagram showing a pulse train pattern of a laser power control signal for controlling the intensity of the laser beam L when data is recorded on the recording layer 14 of the optical recording medium 10.

  As shown in FIG. 3, the pulse train pattern of the laser power control signal used for recording data on the recording layer 14 of the optical recording medium 10 has a level corresponding to the recording power Pw, a level corresponding to the intermediate power Pm, and Between the three levels corresponding to the base power Pb, a level-modulated pulse is formed. The recording power Pw, the intermediate power Pm, and the base power Pb satisfy the relationship Pw> Pm ≧ Pb. Correspondingly, the three levels of the pulse train pattern are also determined.

  In recording data on the recording layer 14, the laser beam L whose power is modulated in accordance with the laser power control signal having the pulse train pattern shown in FIG. 3 is applied to the light transmission layer 17, the second waterproof layer 16, and the second waterproof layer 16. The recording layer 14 is irradiated through the second transparent intermediate layer 15.

  Thus, when the recording layer 14 is irradiated with the laser beam L, the phase state of the recording layer 14 changes and data is recorded on the recording layer 14. Hereinafter, a specific recording mechanism will be described by taking as an example the case where the recording layer 14 contains a single element of a Zn or La metal element and an element of S or O.

That is, when the laser beam L whose power is set to the recording power Pw is irradiated, the recording layer 14 is heated, and a single Zn or La metal contained in the recording layer 14 in the heated recording layer 14 region. The element reacts with S or O to become crystalline ZnS or La ₂ O ₃ , and further amorphous ZnS or La ₂ O ₃ existing around the crystalline ZnS or La ₂ O ₃ Then, the crystal is grown using ZnS or La ₂ O ₃ in a crystalline state as a nucleus.

Thus, the region where the crystalline state ZnS or La ₂ O ₃ is generated differs greatly from the other regions in the reflectivity with respect to the laser beam L having a wavelength λ of 390 nm to 450 nm. Can be recorded.

  Therefore, when the data recorded on the recording layer 14 is reproduced, it is possible to obtain a reproduced signal having good signal characteristics.

Here, the power of the recording power Pw of the laser beam L is such that, by irradiating the laser beam L, the Zn or La metal element and the S or O element contained in the recording layer 14 are reliably bonded. ZnS or La ₂ O ₃ is set to a power at which crystals are generated.

  Further, the power of the intermediate power Pm and the base power Pb is set to a low power at which the Zn or La metal element and the S or O element contained in the recording layer 14 are not combined.

  In particular, the level of the base power Pb is such that the heated region irradiated with the laser beam L of the recording power Pw is quickly cooled by switching the level of the laser beam L to the base power Pb. Set to a very low level.

  As described above, data is recorded on the recording layer 14 of the optical recording medium 10.

  As described above, according to this embodiment, the recording layer 14 includes a Zn or La metal element and an S or O element, and is configured by a single recording film using an inorganic material. Further, it is possible to prevent the characteristics of the recording layer 14 from being deteriorated or the data recorded on the recording layer 14 from being deteriorated by irradiation with sunlight or the like, and to reduce the manufacturing cost of the optical recording medium. .

  In addition, according to this embodiment, the first waterproof layer 12 is provided between the support substrate 11 and the recording layer 14, and the second waterproof layer is provided between the light transmission layer 17 and the recording layer 14. Since the layer 16 is provided, it is possible to prevent moisture from entering the recording layer 14 from the outside of the optical recording medium 10 via the support substrate 11 or the light transmission layer 17. Therefore, it is possible to increase the reliability of the optical recording medium for long-term storage.

Further, in this embodiment, so that the metal element Zn or La, and the elements S or O, is coupled, crystals of ZnS or La ₂ O ₃ is generated, the data is recorded in the recording layer 14 Therefore, in the reflectivity of the recording layer 14 with respect to the laser beam, the difference in reflectivity between the region where the recording mark is formed and the other region can be increased, and therefore, good signal characteristics can be obtained. It is also possible to obtain a reproduced signal having the same.

  FIG. 4 is a schematic perspective view of an optical recording disk according to another preferred embodiment of the present invention, and FIG. 5 is a schematic enlarged sectional view of a portion indicated by B in FIG.

  As shown in FIG. 5, the optical recording disk 100 according to this embodiment includes a support substrate 11, a first waterproof layer 21 formed on the surface of the support substrate 11, and the surface of the first waterproof layer 21. The recording layer 14 formed above, the second waterproof layer 22 formed on the surface of the recording layer 14, and the light transmission layer 17 formed on the surface of the second waterproof layer 22 are provided. .

  In the present embodiment, as shown in FIG. 5, the first waterproof layer 21 is formed on the surface of the support substrate 11 on which the grooves 11 a and 11 b are formed, and the second waterproof layer 22 is the recording layer 14. The first waterproof layer 21 and the second waterproof layer 22 are formed adjacent to the recording layer 14.

  Similar to the first waterproof layer 12 and the second waterproof layer 16 shown in FIGS. 1 and 2, the first waterproof layer 21 and the second waterproof layer 22 are provided from the outside of the optical recording medium 10 to the support substrate. 11 or the light transmitting layer 17 to prevent moisture from entering the recording layer 14.

  When the first waterproof layer 21 and the second waterproof layer 22 are formed adjacent to the recording layer 14, moisture enters the recording layer 14 via the support substrate 11 or the light transmission layer 17. In addition, it is possible to effectively prevent moisture from entering the recording layer 14 via the side surface of the optical recording medium 100. Therefore, according to the present embodiment, it is possible to prevent a long period of time. It is possible to further increase the reliability of the optical recording medium with respect to storage of the image data.

  FIG. 6 is a schematic perspective view of an optical recording disk according to another preferred embodiment of the present invention, and FIG. 7 is a schematic enlarged sectional view of a portion indicated by C in FIG.

  As shown in FIG. 7, the optical recording disk 200 according to this embodiment includes a support substrate 11, a first waterproof layer 31 formed on the surface of the support substrate 11, and a surface of the first waterproof layer 31. The recording layer 14 formed above, the second waterproof layer 32 formed on the surface of the recording layer 14, and the light transmission layer 17 formed on the surface of the second waterproof layer 32 are provided. .

  In the present embodiment, as shown in FIG. 7, the first waterproof layer 31 is formed on the surface of the support substrate 11 on which the grooves 11 a and 11 b are formed, and the second waterproof layer 32 is the recording layer 14. The first waterproof layer 31 and the second waterproof layer 32 are formed adjacent to the recording layer 14.

  The first waterproof layer 31 and the second waterproof layer 32 serve to prevent moisture from entering the recording layer 14 from the outside of the optical recording medium 10 via the support substrate 11 or the light transmission layer 17. And also functions as a part of the recording layer.

  In this embodiment, the material used for forming the first waterproof layer 31 and the second waterproof layer 32 can prevent moisture from entering the recording layer 14 and the recording layer 14 is crystallized. There is no particular limitation as long as it is a dielectric material in which the region adjacent to the crystallized region of the recording layer 14 crystallizes as it is formed, for example, oxide, sulfide, nitride, or these The first waterproof layer 31 and the second waterproof layer 32 can be formed of a dielectric material whose main component is the combination of the above.

More specifically, the first waterproof layer 31 and the second waterproof layer 32 are made of Ni, Ge, Nb, Mo, In, W, Bi, La, Si, Zn, Al, Ta, Ti, Co, Zr. , Pb, Ag, Zn, Sn, Ca, Ce, V, Cu, Fe, Mg, oxides, nitrides, sulfides, fluorides, or composites containing at least one metal selected from the group consisting of It is preferable that a dielectric material composed of, for example, a dielectric material composed mainly of a metal element and an element S or O contained in the adjacent recording layer 14, or ZnS · SiO ₂ . It is particularly preferable that it is contained as a main component.

  In the present embodiment, the second waterproof layer 32 is a layer through which the laser beam L is transmitted when data is recorded on the recording layer 14 or when data recorded on the recording layer 14 is reproduced. Therefore, it is necessary to have sufficient light transmittance.

  The first waterproof layer 31 and the second waterproof layer 32 may be formed of the same dielectric material, but may be formed of different dielectric materials.

  The first waterproof layer 31 can be formed on the surface of the support substrate 11 by a vapor phase growth method using a chemical species containing a constituent element of the first waterproof layer 31, and the second waterproof layer 32. Can be formed on the surface of the recording layer 14 by a vapor phase growth method using chemical species including the constituent elements of the second waterproof layer 32. Examples of the vapor deposition method include a vacuum deposition method and a sputtering method.

  The optical recording medium 200 having the above configuration records data as follows.

  FIG. 8 is a schematic cross-sectional view of the optical recording medium 200 before data is recorded, and FIG. 9 is a schematic cross-sectional view of the optical recording medium 200 after data is recorded.

  In the present embodiment, when data is recorded on the optical recording medium 200, the power-modulated laser beam L is applied to the light transmission layer 17 and the first optical recording medium 10 as in the optical recording medium 10 shown in FIGS. The recording layer 14 is irradiated through the second waterproof layer 32.

Thus, when the recording layer 14 is irradiated with the laser beam L, the recording layer 14 is heated, and in the region of the heated recording layer 14 as in the optical recording medium 10 shown in FIGS. A single element of Zn or La contained in 14 reacts with S or O to form ZnS or La ₂ O ₃ in a crystalline state, and further exists in the vicinity of ZnS or La ₂ O _{3 in} a crystalline state. Crystalline ZnS or La ₂ O ₃ grows with the crystal state ZnS or La ₂ O ₃ as a nucleus.

Thus, as shown in FIG. 9, a recording mark M is formed in which ZnS or La ₂ O ₃ which is a compound of a metal element of Zn or La and an element of S or O is crystallized.

  Further, in this embodiment, when the recording layer 14 is irradiated with the laser beam L and the recording mark M is formed on the recording layer 14, it is included in the first waterproof layer 31 and the first waterproof layer 31. As shown in FIG. 9, the dielectric material is crystallized to form a crystallized region M ′ adjacent to the recording mark M in the first waterproof layer 31 and the first waterproof layer 31.

When the recording mark M is formed on the recording layer 14 by irradiating the laser beam L, the dielectric layer material contained in the first waterproof layer 31 and the second waterproof layer 32 adjacent to the recording layer 14 is crystallized. The reason for this is not necessarily clear, but the recording layer 14 is irradiated with the laser beam L, and the crystalline ZnS or La ₂ O ₃ is used as a nucleus, and the amorphous ZnS or La ₂ O ₃ existing in the periphery. The crystallizing reaction for crystal growth is also transmitted to the first waterproof layer 31 and the second waterproof layer 32. As a result, from the interface with the recording layer 14, the first waterproof layer 31 and the second waterproof layer. It is presumed that the crystallization of the dielectric material progresses toward the inside of 32, and the crystallization region M ′ is formed in the first waterproof layer 31 and the second waterproof layer 32.

  Thus, in the present embodiment, in addition to the formation of the recording mark M on the recording layer 14, crystals are formed in the regions of the first waterproof layer 31 and the second waterproof layer 32 adjacent to the recording mark M. Since the crystallized region M ′ is formed, the difference between the reflectivity of the region where the recording mark M and the crystallized region M ′ are formed and the reflectivity of other regions is increased as a whole. Therefore, it is possible to obtain a reproduction signal having better signal characteristics.

  Therefore, according to this embodiment, it is possible to improve the reliability of the optical recording medium for long-term storage while reducing the manufacturing cost, and to obtain a reproduction signal having even better signal characteristics. It becomes.

  Examples are given below to clarify the effects of the present invention.

  First, a polycarbonate substrate having a thickness of 1.1 mm and a diameter of 120 mm was produced by an injection molding method.

Next, the polycarbonate substrate was set in a sputtering apparatus, and a first waterproof layer having a thickness of 86 nm was formed on the surface of the polycarbonate substrate by a sputtering method using a target made of ZnS · SiO ₂ . Here, a mixed target of ZnS · SiO _2, the molar ratio of ZnS and SiO ₂ was used as a 80:20.

  Next, the polycarbonate substrate on which the first waterproof layer is formed is set in a spin coater, and an ultraviolet curable acrylic resin is applied on the first waterproof layer while rotating the polycarbonate substrate to form a coating film. Then, a stamper having grooves and lands formed thereon is placed on the surface of the coating film, and the coating film is irradiated with ultraviolet rays through the stamper to cure the ultraviolet curable acrylic resin, and the stamper is peeled off. A first transparent intermediate layer having a thickness of 25 μm on which grooves and lands were formed was formed on the surface so that the groove pitch was 0.32 μm.

Next, the polycarbonate substrate on which the second waterproof layer and the second transparent intermediate layer are formed is set in a sputtering apparatus, and both a target mainly composed of ZnS · SiO ₂ and a target mainly composed of Mg are used. Then, a recording layer having a thickness of 32 nm was formed by sputtering. Here, a ZnS / SiO ₂ mixed target having a ZnS: SiO ₂ molar ratio of 80:20 was used.

As a result of measuring the composition of the recording layer after forming the recording layer, the contents of Zn, Si, Mg, O, and S were 23.0 atomic%, 9.0 atomic%, 25.0 atomic%, and 19 respectively. 0.0 atomic% and 24.0 atomic%. The contents of Zn, Si, Mg, O and S contained in the recording layer were measured using a fluorescent X-ray apparatus “RIX2000” (trade name) manufactured by Rigaku Denki Kogyo Co., Ltd., Rh tube, tube voltage = 50 kV, tube X-rays were generated at a current = 50 mA and measured by the FP method. However, since O is contained in the substrate, it is difficult to measure O, and the content of O is assumed to be in the state of SiO ₂ , and the atomic% is twice the Si content. It was said that. Hereinafter, the content of O is the same.

  Next, an ultraviolet curable acrylic resin is applied onto the surface of the recording layer by a spin coating method to form a coating film, and this is irradiated with ultraviolet rays to form a first transparent intermediate having a thickness of 95 μm. A layer was formed.

Next, a first waterproof layer having a thickness of 86 nm was formed on the surface of the first transparent intermediate layer by sputtering using a target made of a mixture of ZnS and SiO ₂ . Mixture target of ZnS and SiO _2, the molar ratio of ZnS and SiO ₂ was used as a 80:20.

  Then, an ultraviolet curable acrylic resin is applied onto the surface of the first waterproof layer by a spin coating method to form a coating film, and this is irradiated with ultraviolet rays to transmit light having a thickness of 5 μm. A layer was formed.

  Thus, an optical recording disk sample # 1 was produced.

  Next, the optical recording disk sample # 1 was set in an optical recording medium evaluation apparatus “DDU1000” (trade name) manufactured by Pulstec Industrial Co., Ltd., a blue laser beam having a wavelength of 405 nm was used as a recording laser, and a numerical aperture Using an objective lens with NA of 0.85, the laser beam is condensed through the light transmission layer, and a recording mark of 8T length is formed on the recording layer of the optical recording disk sample # 1 under the following conditions. The data was recorded. The recording power Pw of the recording laser beam was 6 mW.

Modulation method: (1,7) RLL
Recording linear velocity: 5.3 m / sec Channel bit length: 0.12 μm
Channel clock: 66 MHz
Recording method: on-groove recording Next, using the above-described optical recording medium evaluation apparatus, the recording layer of the optical recording disk sample # 1 was irradiated with a laser beam set at the reproduction power, and the data recorded on the recording layer The C / N ratio of the reproduced signal was measured. Here, the reproduction power of the laser beam was set to 0.3 mW. At this time, the reproducing laser beam was used by changing the same laser power as that of the recording laser beam.

  The C / N ratio of the reproduction signal was measured using a spectrum analyzer “Spectrum Analyzer XK180” (trade name) manufactured by Advantest Corporation.

  The measurement results are shown in Table 1.

  Next, the optical recording disk sample # 1 in which data was recorded on the recording layer was held for 50 hours in an environment of a temperature of 70 ° C. and a relative humidity of 85%, and a storage test was performed. This is to confirm the performance of the optical recording disk after long-term storage in the actual usage environment by storing the optical recording disk sample # 1 for a predetermined time under conditions of higher temperature and humidity than the normal usage environment. The reliability in the actual usage environment was confirmed.

  Next, using the same optical recording medium evaluation apparatus, data recorded on the recording layer of the optical recording disc sample # 1 after the storage test was reproduced, and the C / N ratio of the reproduced signal was measured.

  The measurement results are shown in Table 1.

表１に示されるように、保存試験前の光記録ディスクサンプル＃１、および保存試験後の光記録ディスクサンプル＃１から、記録層に記録したデータを再生したときの再生信号のＣ／Ｎ比は、それぞれ、５４．４ｄＢ、５４．３ｄＢであり、光記録ディスクサンプル＃１は、保存試験後であっても、記録層に記録されたデータを再生したときの再生信号のＣ／Ｎ比が低下せず、長期間の保存に対する高い信頼性を有することが認められた。

As shown in Table 1, the C / N ratio of the reproduction signal when the data recorded on the recording layer is reproduced from the optical recording disk sample # 1 before the storage test and the optical recording disk sample # 1 after the storage test. Are 54.4 dB and 54.3 dB, respectively, and the optical recording disk sample # 1 has a C / N ratio of a reproduction signal when data recorded on the recording layer is reproduced even after a storage test. It was confirmed that it did not decrease and had high reliability for long-term storage.

First, a polycarbonate substrate having grooves and lands formed on the surface was formed by injection molding.
Next, the polycarbonate substrate is set in a sputtering apparatus, and a target having a thickness of 80 nm is formed on the surface of the polycarbonate substrate on which the grooves and lands are formed by sputtering using a target mainly composed of ZnS · SiO ₂ . Two waterproof layers were formed. Here, a ZnS / SiO ₂ mixed target having a molar ratio of 80:20 was used.

Next, the polycarbonate substrate on which the second waterproof layer is formed is set in a sputtering apparatus, and both the target mainly composed of ZnS · SiO ₂ and the target mainly composed of Mg are sputtered to a thickness of 32 nm. A recording layer having a thickness of 1 mm was formed. Here, a ZnS / SiO ₂ mixed target having a ZnS: SiO ₂ molar ratio of 80:20 was used.

  As a result of measuring the composition of the recording layer after forming the recording layer, the contents of Zn, Si, Mg, O, and S were 23.0 atomic%, 9.0 atomic%, 25.0 atomic%, and 19 respectively. 0.0 atomic% and 24.0 atomic%.

Next, a first waterproof layer having a thickness of 85 nm was formed on the recording layer by sputtering using a target made of a mixture of ZnS and SiO ₂ . Mixture target of ZnS and SiO _2, the molar ratio of ZnS and SiO ₂ was used as a 80:20.

  Then, an ultraviolet curable acrylic resin is applied on the surface of the first waterproof layer by a spin coating method to form a coating film, and this is irradiated with ultraviolet rays to transmit light having a thickness of 100 μm. A layer was formed.

  Thus, an optical recording disk sample # 2 was produced.

  Next, an optical recording disk sample # 3 was produced as follows.

First, a polycarbonate substrate having grooves and lands formed on the surface was formed using the same method as that of the optical recording disk sample # 2.
Next, the polycarbonate substrate is set in a sputtering apparatus, and a recording layer having a thickness of 32 nm is formed by a sputtering method using both a target mainly composed of ZnS · SiO ₂ and a target mainly composed of Mg. did. Here, mixed target of ZnS and SiO _2, the molar ratio of ZnS and SiO ₂ was used as a 80:20.

  As a result of measuring the composition of the recording layer after forming the recording layer, the contents of Zn, Si, Mg, O, and S were 23.0 atomic%, 9.0 atomic%, 25.0 atomic%, and 19 respectively. 0.0 atomic% and 24.0 atomic%.

  Next, an ultraviolet curable acrylic resin is applied onto the surface of the recording layer by spin coating to form a coating film, and this is irradiated with ultraviolet rays to form a light transmission layer having a thickness of 100 μm. did.

  Thus, an optical recording disk sample # 3 was produced.

  Next, the optical recording disk samples # 2 and # 3 are sequentially set in the same optical recording medium evaluation apparatus as in Example 1, and irradiated with a laser beam to the recording layers of the optical recording disk samples # 2 and # 3. 8T-long recording marks were formed to record data.

  In recording data, the wavelength of the laser beam was 405 nm, the numerical aperture NA of the objective lens was 0.85, and the recording power Pw of the laser beam was 6 mW.

  Next, using the above-described optical recording medium evaluation apparatus, the recording layers of the optical recording disk samples # 2 and # 3 are sequentially irradiated with the laser beam set to the reproduction power, and the recorded data is reproduced, Using the same spectrum analyzer as in Example 1, the degree of modulation and C / N ratio of the reproduction signal were measured. Here, the modulation degree of the reproduction signal is determined based on the level of the reproduction signal obtained by irradiating the reproduction laser beam to the area where the recording mark is not formed, and the reproduction laser beam is formed in the area where the recording mark is formed. The value obtained by subtracting the level of the reproduction signal obtained by irradiating the laser beam is divided by the level of the reproduction signal obtained by irradiating the region where no recording mark is formed with the laser beam.

  In reproducing data, the wavelength of the laser beam was 405 nm, the numerical aperture NA of the objective lens was 0.85, and the reproduction power of the laser beam was 0.3 mW.

  The measurement results are shown in Table 2.

表２に示されるように、光記録ディスクサンプル＃２および＃３に記録されたデータを再生したときの再生信号の変調度は、それぞれ、５０．５％、４２．３％であり、光記録ディスクサンプル＃２においては、光記録ディスクサンプル＃３に比べて、記録されたデータを再生したときの再生信号の変調度が、大幅に高くなることが認められた。

As shown in Table 2, the modulation degrees of the reproduction signals when reproducing the data recorded on the optical recording disk samples # 2 and # 3 are 50.5% and 42.3%, respectively. In disc sample # 2, it was recognized that the degree of modulation of the reproduction signal when the recorded data was reproduced was significantly higher than in optical recording disc sample # 3.

  Further, as shown in Table 2, the C / N ratios of the reproduction signals when reproducing the data recorded on the optical recording disk samples # 2 and # 3 are 56.6 dB and 54.0 dB, respectively. Also in the C / N ratio of the reproduction signal, it was confirmed that the optical recording disk sample # 2 can obtain a higher value than the optical recording disk sample # 3.

Thus, it has been found that a reproduction signal having good signal characteristics can be obtained in the optical recording disk sample # 2.

  Data recording optical recording disk samples # 2 and # 3 were held for 50 hours in an environment of a temperature of 80 ° C. and a relative humidity of 85%, and a storage test was performed.

  Next, using the same optical recording medium evaluation apparatus, the data recorded on the optical recording disc samples # 2 and # 3 after the storage test is reproduced, and the C / N ratio of the reproduced signal is measured using the same spectrum analyzer. did.

  The measurement results are shown in Table 3. Table 3 shows the C / N ratio when the recorded data is reproduced for the optical recording disk samples # 2 and # 3 measured in Example 2, as the values before “preservation test”. Has been.

表３に示されるように、光記録ディスクサンプル＃２においては、保存試験前および保存試験後に、記録層に記録したデータを再生したときの再生信号のＣ／Ｎ比が、それぞれ、５６．６ｄＢ、５６．１ｄＢであり、光記録ディスクサンプル＃２は、保存試験後であっても、記録層に記録されたデータを再生したときの再生信号のＣ／Ｎ比が、ほとんど変わらなかったのに対し、光記録ディスクサンプル＃３においては、保存試験後に、記録層に記録したデータを再生したときの再生信号のＣ／Ｎ比が、測定できず、したがって、光記録ディスクサンプル＃２においては、光記録ディスクサンプル＃３に比べて、長期間の保存に対して、高い信頼性を有することが認められた。

As shown in Table 3, in the optical recording disk sample # 2, the C / N ratio of the reproduction signal when reproducing the data recorded on the recording layer before and after the storage test is 56.6 dB, respectively. 56.1 dB, and the optical recording disk sample # 2 had a C / N ratio of the reproduction signal when the data recorded on the recording layer was reproduced, even after the storage test. On the other hand, in the optical recording disk sample # 3, the C / N ratio of the reproduction signal when the data recorded on the recording layer is reproduced after the storage test cannot be measured. Compared to optical recording disk sample # 3, it was found to have higher reliability for long-term storage.

  In the above embodiment, when the state of the recording layer was confirmed using an Auger spectroscopic analyzer, an optical film thickness measuring device, and a transmission electron microscope, the recording layer irradiated with a laser beam set to a recording power was used. In this region, the presence of the simple substance of the metal element M and the crystal growth of the compound with the metal element M were observed.

In the present embodiment, it is assumed that the recording layer includes a single element of the metal element M in a state where the presence of the single element of the metal element M is recognized by the following analysis and determination. Further, by the following analysis and judgment, an element that forms a crystal of the compound with the metal element M by combining the state in which the crystal growth of the compound of the metal element M and the element X is recognized with the simple substance of the metal element M. X is assumed to be included in the recording layer.

  As a specific method, three optical recording disk samples were prepared under the same conditions, and data was recorded in the same manner as in Example 1 in which data was recorded on a part of the recording layers of the three optical recording disk samples. Was recorded.

Next, for one of the three optical recording disk samples on which the data was recorded, the light transmission layer was cut with a cutter and peeled off, and the second waterproof layer was removed, the recording layer was exposed and exposed. A dielectric film having a thickness of 20 nm (for example, Al ₂ O ₃ when the recording layer contains ZnS as a main component) and a metal film having a thickness of 100 nm (for example, Al) are formed on the surface of the recording layer. Were sequentially formed by a sputtering method. For the metal film and the dielectric film, it is necessary to use materials other than the metal element M contained in the recording layer so as not to affect the analysis. Here, the metal film is formed in order to prevent the optical recording disk sample from being charged during the measurement using the Auger spectroscopic analyzer. Next, the surface of the metal film of the optical recording disk sample on which the dielectric film and the metal film were formed was locally sputtered to form a hole of about 2 mm so that a part of the surface of the recording layer was exposed.

  Next, in the optical recording disk sample on which the data was recorded, the energy spectrum was measured using an Auger spectroscopic analyzer for the area where the data of the recording layer was recorded and the area where the data of the recording layer was not recorded. Here, when measuring the energy spectrum, an Auger spectroscopic analyzer “SAM680” manufactured by ULVAC-PHI Co., Ltd. was used, and the measurement conditions were set to an acceleration voltage of 5 kV, a Tilt of 30 deg, a sample current of 10 nA, and an Ar ion beam sputter etching acceleration voltage of 2 kV. Set and measure.

  Thus, as a result of measuring the energy spectrum of the recording layer data recorded area and the recording layer data unrecorded area, the metal energy spectrum and the compound energy spectrum are mixed in the unrecorded area. In the region where data was recorded, only the energy spectrum of the compound was observed. From this change in the spectrum, it was determined that the recording layer contained the metal element M.

  Next, the other one of the three optical recording disc samples is cut with a cutter to cut off the light transmitting layer, the second waterproof layer and the recording layer, and the separated light transmitting layer, The second waterproof layer and the recording layer were adhered onto the slide glass using an ultraviolet curable resin so that the light transmission layer was in contact with the slide glass.

  In the optical recording disk sample thus formed, the optical absorptance with respect to a laser beam having a wavelength of 405 nm using an optical film thickness measuring device for the recording layer data recorded area and the recording layer data unrecorded area. Was measured. Here, in measuring the light absorption rate, an optical film thickness measuring device “ETA-RT” (trade name) manufactured by steag ETA-OPTIK Co., Ltd. was used.

  Thus, as a result of measuring the optical absorptance with respect to the laser beam having a wavelength of 405 nm for the recording layer data recorded area and the recording layer data unrecorded area, 34% was obtained in the area where the data was not recorded. It has been found that it has a light absorptance, while the area where data is recorded has a light absorptance of 27%. The decrease in light absorptance is because the free electrons of the metal element M absorb a lot of light and make a compound with the element X, so that the free electrons of the metal element M decrease and the light absorption decreases. It seems that it has become smaller. Similar to the change in the energy spectrum by Auger spectroscopic analysis, it was determined that the recording film contained a single element of the metal element M due to the decrease in the light absorption rate.

  Thus, by measuring the energy spectrum by the Auger spectroscopic analyzer, the energy spectrum of the metal and the energy spectrum of the compound are mixed in the area where the data is not recorded, while the energy spectrum of the compound is mixed in the area where the data is recorded. The result that only the energy spectrum was confirmed was obtained, and the optical absorptance in the area where the data was recorded by the measurement of the optical absorptivity by the optical film thickness measurement device compared to the area where the data was not recorded. From these results, the presence of the simple substance of the metal element M in the recording layer and the region of the recording layer irradiated with the laser beam for recording indicate that the simple substance of the metal element M is the element X. It was judged that the crystals of the compound were produced by the combination.

  Next, the electron diffraction pattern of the recording mark was measured for the remaining one of the three optical recording disk samples on which the data was recorded, using a transmission electron microscope apparatus. At this time, as the transmission electron microscope, “JEM-3010” (trade name) manufactured by JEOL Ltd. was used, and the acceleration voltage was set to 300 kV.

  Here, the optical recording disk sample was cut using a microtome to prepare a sample for a transmission electron microscope. As a result of measuring the electron diffraction pattern of the recording layer in the cut section, a ZnS broad diffraction ring was observed in the area where data was not recorded, whereas a ZnS diffraction spot was observed in the area where data was recorded. Admitted. From these results, it was determined that crystallization of ZnS was generated in the region of the recording layer irradiated with the recording laser beam.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

  For example, in the optical recording medium 100 according to the embodiment shown in FIGS. 4 and 5, the support substrate 11, the first waterproof layer 21 formed on the surface of the support substrate 11, and the first waterproof layer 21. A recording layer 14 formed on the surface of the recording layer 14, a second waterproof layer 22 formed on the surface of the recording layer 14, and a light transmission layer 17 formed on the surface of the second waterproof layer 22. The first waterproof layer 21 and the second waterproof layer 22 are both formed adjacent to the recording layer 14, but between the first waterproof layer 21 and the recording layer 14, or the second Another layer may be interposed between the waterproof layer 22 and the recording layer 14.

  Further, in the optical recording medium 200 according to the embodiment shown in FIGS. 6 and 7, the support substrate 11, the first waterproof layer 31 formed on the surface of the support substrate 11, and the first waterproof layer 31. A recording layer 14 formed on the surface of the recording layer 14, a second waterproof layer 32 formed on the surface of the recording layer 14, and a light transmission layer 17 formed on the surface of the second waterproof layer 32. The first waterproof layer 31 and the second waterproof layer 32 are both formed adjacent to the recording layer 14, and a crystallization region M ′ is formed in a region in contact with the recording mark M of the recording layer 14. Although either of the first waterproof layer 31 and the second waterproof layer 32 is adjacent to the recording layer 14, only the waterproof layer formed adjacent to the recording layer 14 has a crystallization region. M ′ may be formed.

  Further, in the optical recording media 10, 100, 200 according to the embodiments shown in FIGS. 1 and 2, 4 and 5, and FIGS. 6 and 7, the first waterproof layers 12, 21, 31 are provided. Both are formed between the support substrate 11 and the recording layer 14, but the first waterproof layers 12, 21, 31 are on the main surface of the support substrate 11 opposite to the recording layer 14 side. It may be formed.

  Further, in the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 4 and 5, and FIGS. 6 and 7, the first is formed on the surface of the support substrate 11. Although the waterproof layers 12, 21, and 31 are formed, the support substrate 11 is formed using polystyrene, polyolefin, or the like, which is a resin having water resistance (water absorption), and the support substrate 11 functions as a waterproof layer. You may comprise as follows. In this case, the first waterproof layers 12, 21, 31 formed on the surface of the support substrate 11 can be omitted.

  Further, in the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 4 and 5, and FIGS. 6 and 7, the first is formed on the surface of the support substrate 11. Although the waterproof layers 12, 21, and 31 are formed, the first waterproof layers 12, 21, and 31 are formed so as to contain a metal element as a main component, and the first waterproof layers 12, 21, and 31 are reflected. You may form so that it may have the function of a layer.

In the above embodiment, the target containing ZnS.SiO ₂ or La.Si.O.N as a main component and the target containing as a main component at least one metal element selected from the group consisting of Mg, Al, and Ti. The recording layer 14 is formed by sputtering using the above method. As a result of the film formation, the recording layer 14 is irradiated with a metal element M of Zn or La and a recording laser beam. Therefore, it is only necessary to include an element of S or O that combines with the metal element M to form a crystal of the compound with the metal element M, and includes a target mainly composed of ZnS, Mg, Al, and Ti. The recording layer 14 may be formed by sputtering using a target containing at least one metal element selected from the group consisting of as a main component. .

  The optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, FIG. 4 and FIG. 5, and FIG. 6 and FIG. A hard coat layer containing the hard coat composition as a main component may be provided in place of the transmissive layer 17 or on the surface of the light transmissive layer 17, and further, a lubricity and antifouling function is imparted. Therefore, a lubricant may be included in the hard coat layer, or a lubricant layer containing the lubricant as a main component may be separately provided on the surface of the hard coat layer.

  Furthermore, in the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 4 and 5, and FIGS. 6 and 7, the laser beam L passes through the light transmission layer 17. The present invention is configured so that the recording layer 14 is irradiated. However, the present invention relates to a light transmissive substrate having a thickness of about 0.6 mm, a dummy substrate having a thickness of about 0.6 mm, It is also possible to apply to a DVD type optical recording medium provided with a recording layer between a transparent substrate and a dummy substrate.

FIG. 1 is a schematic perspective view of an optical recording medium 10 according to a preferred embodiment of the present invention. FIG. 2 is a schematic enlarged cross-sectional view of a portion indicated by A in FIG. FIG. 3 is a diagram showing a pulse train pattern of a laser power control signal for controlling the intensity of the laser beam L when data is recorded on the optical recording medium 10. FIG. 4 is a schematic perspective view of an optical recording medium 100 according to another preferred embodiment of the present invention. FIG. 5 is a schematic enlarged cross-sectional view of the portion indicated by B in FIG. FIG. 6 is a schematic perspective view of an optical recording medium 200 according to another preferred embodiment of the present invention. FIG. 7 is a schematic enlarged cross-sectional view of a portion indicated by C in FIG. FIG. 8 is a schematic cross-sectional view of the optical recording medium 200 before data is recorded. FIG. 9 is a schematic cross-sectional view of the optical recording medium 200 after data is recorded.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical recording medium 11 Substrate 11a Groove 11b Land 12 First waterproof layer 13 First transparent intermediate layer 14 Recording layer 15 Second transparent intermediate layer 16 Second waterproof layer 17 Light transmission layer 21 First waterproof layer 22 Second waterproof layer 31 First waterproof layer 32 Second waterproof layer 100 Optical recording medium 200 Optical recording medium

Claims (2)

A first waterproof layer, and a second waterproof layer, and a recording layer formed between said second waterproof layer and the first waterproof layer, said first waterproof layer and the second At least one of the waterproof layers is formed adjacent to the recording layer, and the recording layer is formed of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn And at least one metal element M selected from the group consisting of La and a recording laser beam are irradiated to bond the metal element M to a crystal of a compound with the metal element M. resulting S or O-containing Mutotomoni, further, Mg, at least one metallic element selected from the group consisting of Al and Ti, when containing Mg, the content of Mg is not 18.5 atomic% to 42 atomic% Thus, when Al is included, It is not 11 atomic% content of l such that 70 atomic%, when containing Ti is to have no 8 atomic% Ti content viewed free so that 38 atomic%, are formed adjacent to the recording layer The waterproof layer includes a dielectric material as a main component, and when the recording laser beam is irradiated, a recording mark having a reflectance different from that of the other region is formed on the recording layer, and the at least An optical recording medium characterized in that at least a part of a region in contact with the recording mark of one waterproof layer is crystallized to form a crystallized region . The optical recording medium according to claim 1, wherein data is recorded using a laser beam having a wavelength of 380 nm to 450 nm, and the recorded data is reproduced.

Images