JP2005115979A - Optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium having a plurality of recording layers, which desirably records data to and reproduces the recorded data from the recording layer furthest from a laser beam incident surface, for desirably records data to and reproduces the recorded data from the recording layers other than the furthest recording layer from the laser beam incident surface, and enhances shelf reliability for a long time. <P>SOLUTION: The optical recording medium is provided with: a reflection layer 21 as a first waterproof layer; a second dielectric layer 22; a waterproof layer 16 as a second waterproof layer; and first, second and third recording layers 20, 30 and 40 formed between the first and the second waterproof layers. The second and the third recording layers 30 and 40 contain at least one simple of a 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 and an element X bonded to the simple of the metal element M by irradiation with a laser beam L for recording to form a crystal of a compound with the metal element M. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a write-once type optical recording medium having a plurality of recording layers, and in particular, to a recording layer that includes a plurality of recording layers and is farthest from the light incident surface of a laser beam as desired. Can be reproduced, and the recorded data can be reproduced, and the data can be recorded on the recording layer other than the recording layer farthest from the light incident surface of the laser beam as desired, and the recorded data can be reproduced. In addition, the present invention relates to an optical recording medium that can improve reliability for long-term storage.

  Conventionally, optical recording media represented by CDs and DVDs are widely used as recording media for recording digital data. The recording capacity required for such an optical recording medium increases year by year, and various proposals have been made to increase the recording capacity of the optical recording medium.

  As one of them, an optical recording medium having two recording layers has been proposed and has already been put into practical use in DVD-Video and DVD-ROM, which are read-only optical recording media.

  As described above, a read-only optical recording medium having two recording layers has a structure in which two substrates on which the prepits constituting the recording layer are formed are stacked via an intermediate layer. doing.

  In recent years, an optical recording medium having two information recording layers has been proposed as a rewritable optical recording medium on which data can be recorded by a user (see Japanese Patent Laid-Open No. 2001-243655).

  In a rewritable optical recording medium having two recording layers, a recording layer is formed by a recording film and a dielectric layer (protective layer) formed with the recording film interposed therebetween. And are stacked via an intermediate layer.

  When recording data on such a rewritable optical recording medium having two recording layers, the laser beam is focused on one of the recording layers, and the laser beam power is higher than the reproduction power Pr. By setting the recording power Pw to a sufficiently high level and irradiating the recording layer with a laser beam, the phase state of the recording film included in the recording layer is changed, and a recording mark is formed on a predetermined portion of the recording layer. Form.

  Since the recording mark thus formed has a different reflectance from the blank area where the recording mark is not formed, the laser beam is focused on one of the recording layers and the power is set to the reproduction power Pr. The data recorded on the recording layer can be reproduced by irradiating the recording layer with the beam and detecting the amount of laser beam from the recording layer.

  Thus, in a rewritable optical recording medium in which two recording layers are formed, the recording layer is irradiated with a laser beam with the laser beam focused on one of the recording layers. Since the data recorded on the recording layer and the data recorded on the recording layer are reproduced, the data is recorded on the recording layer far from the light incident surface (hereinafter referred to as “first recording layer”). When the recorded data is reproduced, the first recording layer is irradiated with a laser beam through a recording layer closer to the light incident surface (hereinafter referred to as “second recording layer”). Will be.

Accordingly, in order to record data on the first recording layer and reproduce the data recorded on the first recording layer as desired, the second recording layer is sufficiently It is necessary to have a high light transmittance.
JP 2001-243655 A

  On the other hand, when reproducing the data recorded on the second recording layer, in order to obtain a reproduction signal having good signal characteristics, the second recording layer includes an area where a recording mark is formed, It is required to be formed of a material having a sufficiently large reflectance difference from the blank region.

  Similar problems occur in the write-once recording medium having two recording layers, and the second recording layer is required to have the same characteristics.

  However, all the recording layers other than the recording layer farthest from the light incident surface of the laser beam have a sufficiently high light transmittance with respect to the laser beam, and a region where a recording mark is formed, and a blank An optical recording medium with two or more recording layers has been developed that has a sufficiently large difference in reflectance from the area and can obtain a reproduced signal with good signal characteristics as desired. Was not.

  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 includes a plurality of recording layers, can record data as desired on the recording layer farthest from the light incident surface of the laser beam, and can reproduce the recorded data. Data can be recorded on the recording layer other than the recording layer farthest from the light incident surface of the beam as desired, and the recorded data can be reproduced, and the reliability for long-term storage can be improved. An object of the present invention is to provide an optical recording medium that can be used.

  The object of the present invention includes a first waterproof layer, a second waterproof layer, and a plurality of recording layers formed between the first waterproof layer and the second waterproof layer, At least one recording layer of the plurality of recording layers 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. A single element of a kind of metal element M, and an element X that forms a compound crystal with the metal element M by being irradiated with a recording laser beam. It is achieved by an optical recording medium characterized by the following.

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

  In the present invention, at least one of the plurality of recording layers is a group consisting of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and La. A single element of at least one metal element M selected from the above and an element X that forms a compound crystal with the metal element M by being irradiated with a recording laser beam; Are formed to include.

  According to the research of the present inventors, when at least one recording layer of the plurality of recording layers is configured to have such a composition, the plurality of recording layers are sufficient for the laser beam. Has been found to have good light transmission.

  Therefore, according to the present invention, it is possible to suppress the laser beam power from decreasing before the laser beam reaches the lowermost recording layer farthest from the light incident surface. Data can be recorded on the recording layer as desired.On the other hand, when reproducing data recorded on the lowermost recording layer, the laser beam reflected by the lowermost recording layer is Since the power of the laser beam can be suppressed to a minimum before reaching the light incident surface, the data recorded on the lowermost recording layer can be reproduced as desired.

  In the present invention, when the recording layer containing the simple substance of the metal element M and the element X is irradiated with the recording laser beam and the data is recorded, the simple substance of the metal element M and the element X are combined, Data is recorded by generating crystals of the compound.

  Thus, when data is recorded, the difference in reflectance with respect to the laser beam can be increased between the region where the simple substance of the metal element M and the compound of the element M are crystallized and the other region. Therefore, it is possible to record data and reproduce the recorded data not only on the lowermost recording layer but also on a recording layer other than the lowermost recording layer.

  Furthermore, in the present invention, a plurality of recording layers are 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, since the first waterproof layer and the second waterproof layer can prevent moisture from entering the plurality of recording layers, the data recorded on the recording layer is deteriorated. Alternatively, it is possible to prevent the characteristics of the recording layer from changing, and it is therefore possible to improve the reliability of the optical recording medium for long-term storage.

  In a preferred embodiment of the present invention, at least one of the first waterproof layer and the second waterproof layer 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.

  In a preferred embodiment of the present invention, the recording apparatus includes at least one dielectric layer formed adjacent to at least one recording layer of the plurality of recording layers, 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 at least a part of the region in contact with the recording mark of the at least one dielectric layer is crystallized to form a crystallized region. It is comprised so that.

  According to the present invention, at the same time that a recording mark is formed in the recording layer, at least a part of the dielectric layer in contact with the recording mark is crystallized to form a crystallized region. Thus, 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 is obtained. It becomes possible.

  In a further preferred embodiment of the present invention, the element X is S or O.

  When the element X is 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, and N or P When the element is a group 5B element, the reactivity is too weak to easily react with the metal element M, and the recording sensitivity may be deteriorated.

  On the other hand, when the element X is O or S, both of which are a group 6B, the reactivity is neither too high nor too weak, and it is crystallized by reacting with the metal element M as desired. Is preferable.

  In a further preferred embodiment of the present invention, the recording layer containing the single element of the metal element M and the element X further contains at least one metal element selected from the group consisting of Mg, Al and Ti.

  In the present invention, when the recording layer containing the simple metal element M and the element X contains Mg, the amount of Mg added is preferably 18.5 atomic% to 33.7 atomic%, and more preferably 20 atomic%. More preferably, it is 33.5 atomic%, and when Al is contained, the amount of Al added is preferably 11 atomic% to 40 atomic%, and preferably 18 atomic% to 32 atomic%. Further, when Ti is contained, the amount of Ti added is preferably 8 atomic% to 34 atomic%, more preferably 10 atomic% to 26 atomic%.

  In a further preferred embodiment of the present invention, the recording layer farthest from the light incident surface of the laser beam among the plurality of recording layers includes a first recording film containing Cu as a main component, and Si as a main component. And a second recording film.

  According to a further preferred embodiment of the present invention, the recording layer farthest from the light incident surface of the laser beam among the plurality of recording layers is a first recording film containing Cu as a main component, and Si as a main component. And the second recording film included, so that the noise level of the reproduction signal when reproducing the data recorded on the recording layer farthest from the light incident surface can be further reduced and before and after recording. The difference in reflectance can be increased.

  In a further preferred embodiment of the present invention, a reflective layer for reflecting the laser beam is provided, and the recording layer farthest from the light incident surface of the laser beam is between the reflective layer and the light incident surface of the laser beam. Is formed.

  According to a further preferred embodiment of the present invention, when reproducing data recorded on the recording layer farthest from the light incident surface, the laser beam incident from the light incident surface side is reflected by the surface of the reflective layer, The laser beam reflected by the reflective layer interferes with the laser beam reflected by the recording layer farthest from the light incident surface, and as a result, the reflectance difference before and after recording can be increased, and therefore The data recorded on the recording layer farthest from the light incident surface of the laser beam can be reproduced with high sensitivity.

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

  Recording comprising a single element of a metal element M of Zn or La and an element X that forms a compound crystal with the metal element M by being irradiated with a recording laser beam. Since the layer exhibits good optical characteristics with respect to a laser beam having a wavelength λ of 380 nm to 450 nm, data is recorded using the laser beam having a wavelength λ of 380 nm to 450 nm, and the recorded data is reproduced. It is preferable.

  According to the present invention, a plurality of recording layers are provided, data can be recorded as desired on the recording layer farthest from the light incident surface of the laser beam, and the recorded data can be reproduced, and the laser can be reproduced. Data can be recorded on the recording layer other than the recording layer farthest from the light incident surface of the beam as desired, and the recorded data can be reproduced, and the reliability for long-term storage can be improved. An optical recording medium that can be used 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 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 reflective layer 21, the second dielectric layer 22, the first recording layer 20, the first dielectric layer 24, the first transparent intermediate layer 12, and the second recording. A layer 30, a second transparent intermediate layer 13, a third recording layer 40, a third transparent intermediate layer 14, a waterproof layer 16, and a light transmission layer 17 are provided.

  The first recording layer 20, the second recording layer 30 and the third recording layer 40 are recording layers for recording data, respectively. The optical recording medium 10 according to this embodiment includes three recording layers. Have.

  As shown in FIG. 2, the optical recording medium 10 according to the present embodiment is configured such that the light transmission layer 17 is irradiated with the laser beam L, and the light incident surface 17 a is formed by one surface of the light transmission layer 17. Is configured.

  As shown in FIG. 2, the first recording layer 20 constitutes the recording layer farthest from the light incident surface 17a, and the third recording layer 40 constitutes the recording layer closest to the light incident surface 17a. Yes.

  Data was recorded on the first recording layer 20, the second recording layer 30 or the third recording layer 40, and recorded on the first recording layer 20, the second recording layer 30 or the third recording layer 40. When data is reproduced, a blue laser beam L having a wavelength λ of 380 nm to 450 nm is irradiated from the light incident surface 17a side, and the focal points thereof are the first recording layer 20, the second recording layer 30, and the first recording layer. One of the three recording layers 40 is set.

  Accordingly, when data is recorded on the first recording layer 20 and the data recorded on the first recording layer 20 is reproduced, the first recording layer 20 and the third recording layer 40 are used for the first recording layer 20. When the recording layer 20 is irradiated with the laser beam L, data is recorded on the second recording layer 30, and data recorded on the second recording layer 30 is reproduced, the third recording layer 40 is used to The second recording layer 30 is irradiated with the laser beam L.

  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 viewpoints of workability, surface roughness, and the like. In this embodiment, the support substrate 21 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, grooves 11 a and lands 11 b are alternately formed on the surface of the support substrate 11. The grooves 11a and / or lands 11b formed on the surface of the support substrate 11 function as a guide track for the laser beam L when data is recorded on the first recording layer 20 and when data is reproduced.

  The depth of the groove 11a is not particularly limited, but is preferably set to 10 nm to 40 nm, and the pitch of the groove 11a 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 reflective layer 21 is formed on the surface of the support substrate 11.

  The reflection layer 21 reflects the laser beam L incident from the light incident surface 17a and emits the light again from the light incident surface 17a, and is applied to the first recording layer 20 described later by irradiation with the laser beam L. It plays a role of effectively dissipating the generated heat.

  Further, in the present embodiment, the reflective layer 21 functions as a first waterproof layer together with a second dielectric layer 22 to be described later, and the first dielectric layer is formed from the outside of the optical recording medium 10 via the support substrate 11. The recording layer 20, the second recording layer 30, and the third recording layer 40 serve to prevent moisture from entering.

  The material for forming the reflective layer 21 is not particularly limited, and is formed of Mg, Al, Ti, Cr, Fe, Co, Ni, Cu, Zn, Ge, Ag, Pt, Au, or the like. Can do. Among these, Al, Au, Ag, Cu or alloys thereof are preferably used for forming the reflective layer 21 because they have high reflectance and high thermal conductivity.

  The reflective layer 21 is preferably formed to have a thickness of 20 nm to 200 nm. If the thickness of the reflective layer 21 is less than 20 nm, it is difficult to sufficiently increase the reflectance of the reflective layer 21 and it is difficult to dissipate the heat generated in the first recording layer 20. On the other hand, if the thickness of the reflective layer 21 exceeds 200 nm, it takes a long time to form the reflective layer 21, so that productivity is reduced and cracks may occur due to internal stress or the like. There is also.

  As shown in FIG. 2, a second dielectric layer 22 is formed on the surface of the reflective layer 21.

  The second dielectric layer 22 has a function of preventing thermal deformation of the support substrate 11, and also functions as a protective film that protects the first recording layer 20 together with the first dielectric layer 24.

The material for forming the second dielectric layer 22 is a transparent dielectric material in the wavelength region of the laser beam L, and the first recording layer 20, the second recording layer 30, and the third recording layer. It is not particularly limited as long as moisture can be prevented from entering the layer 40. 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-containing oxide, nitride, sulfide, fluoride, or a composite thereof containing at least one metal selected from the group consisting of It is preferable to form the second dielectric layer 22 using a dielectric material made of a material. For example, the second dielectric layer 22 is made of a material mainly composed of a dielectric made of ZnS · SiO _2. Especially preferred to form Yes.

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.

  As shown in FIG. 2, a first recording layer 20 is formed on the surface of the second dielectric layer 22, and the second recording layer 20 includes the first recording film 23a and the second recording layer 23a. Recording film 23b.

  The first recording film 23a and the second recording film 23b are recording films for recording data.

  In the present embodiment, the first recording film 23a contains Cu as a main component, and the second recording film 23b contains Si as a main component.

  It is preferable that at least one element selected from the group consisting of Al, Zn, Sn, Mg, and Au is added to the first recording film 23a containing Cu as a main component. When these elements are added to a recording film containing Cu as a main component, it is possible to reduce the noise level of a reproduction signal and improve the reliability for long-term storage. .

  The first recording film 23a and the second recording film 23b are preferably formed to have a total thickness of 2 nm to 40 nm.

  When the total thickness of the first recording film 23a and the second recording film 23b is less than 2 nm, the change in reflectance before and after the laser beam L irradiation is reduced, and a reproduction signal having a high C / N ratio is obtained. On the other hand, if the total thickness of the first recording film 23a and the second recording film 23b exceeds 40 nm, the recording sensitivity is deteriorated.

  The thicknesses of the first recording film 23a and the second recording film 23b are not particularly limited, but the ratio between the thickness of the second recording film 23b and the thickness of the first recording film 23a. That is, the thickness of the second recording film 23b / the thickness of the first recording film 23a is preferably 0.2 to 5.0.

  As shown in FIG. 2, a first dielectric layer 24 is formed on the surface of the second recording film 23b.

  Together with the second dielectric layer 22, the first dielectric layer 24 functions as a protective film that protects the first recording layer 20.

  The material for forming the first dielectric layer 24 is not particularly limited as long as it is a transparent dielectric material in the wavelength region of the laser beam L, and is the same as that of the second dielectric layer 22. It can be formed by material.

  As shown in FIG. 2, the first transparent intermediate layer 12 is formed on the surface of the first dielectric layer 24.

  The first transparent intermediate layer 12 has a function of separating the first dielectric layer 24 and the second recording layer 30 with a sufficient physical and optical distance.

  As shown in FIG. 2, grooves 12 a and lands 12 b are alternately formed on the surface of the first transparent intermediate layer 12. The groove 12 a and / or land 12 b formed on the surface of the first transparent intermediate layer 12 is a laser when data is recorded on the second recording layer 30 and when data is reproduced from the second recording layer 30. It functions as a guide track for the beam L.

  As shown in FIG. 2, the second recording layer 30 is formed on the surface of the first transparent intermediate layer 12, and the second transparent intermediate layer 13 is formed on the surface of the second recording layer 30. Has been.

  The second transparent intermediate layer 13 has a function of separating the second recording layer 30 and the third recording layer 40 with a sufficient physical and optical distance.

  As shown in FIG. 2, grooves 13 a and lands 13 b are alternately formed on the surface of the second transparent intermediate layer 13. The grooves 13a and / or lands 13b formed on the surface of the second transparent intermediate layer 13 are lasers when data is recorded on the third recording layer 40 and when data is reproduced from the third recording layer 40. It functions as a guide track for the beam L.

  The depth and pitch of the grooves 12 a and 13 a can be set to be approximately the same as the depth and pitch of the groove 11 a provided on the surface of the support substrate 11.

  The first transparent intermediate layer 12 records data on the first recording layer 20, and when reproducing the data recorded on the first recording layer 20, the laser beam L passes through and the second transparent intermediate layer 12 The layer 13 records data on the first recording layer 20, reproduces data recorded on the first recording layer 20, and records data on the second recording layer 30. When the data recorded on the layer 30 is reproduced, the laser beam L passes therethrough, so it is necessary to have a high light transmittance.

  The first transparent intermediate layer 12 and the second transparent intermediate layer 13 are each preferably formed to have a thickness of 5 μm to 50 μm, and more preferably 10 μm to 40 μm. ,It is formed.

  The material for forming the first transparent intermediate layer 12 and the second transparent intermediate layer 13 is not particularly limited, but it is preferable to use an ultraviolet curable acrylic resin.

  As shown in FIG. 2, a third recording layer 40 is formed on the surface of the second transparent intermediate layer 13.

  The second recording layer 30 and the third recording layer 40 are recording layers for recording data, and are each constituted by a single recording film.

  In this embodiment, the second recording layer 30 and the third recording layer 40 are made of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and A single element of at least one metal element M selected from the group consisting of La and an element of S or O is included in a single form.

  In the present embodiment, the thicknesses of the second recording layer 30 and the third recording layer 40 are the same as the thicknesses of the second recording layer 30 and the third recording layer 40, respectively, as D2 and D3. In this case, it is formed so that the relationship of D2> D3 is satisfied.

  Since the second recording layer 30 is a layer through which the laser beam L is transmitted when data is recorded on the first recording layer 20 and data recorded on the first recording layer 20 is reproduced. The recording layer 30 has sufficient light to record a high level reproduction signal when data is recorded on the first recording layer 20 and the data recorded on the first recording layer 20 is reproduced. The third recording layer 40 needs to have a transmittance, and the third recording layer 40 records data on the first recording layer 20 or the second recording layer 30, and the first recording layer 20 or the second recording layer 30. When reproducing the data recorded on the recording layer 30, the third recording layer 40 records data on the first recording layer 20 or the second recording layer 30 because the laser beam L is transmitted therethrough. Then, the data recorded on the first recording layer 20 or the second recording layer 30 was reproduced. To come, it is necessary to have a sufficient light transmittance to be able to obtain a high level of the reproduced signal.

  On the other hand, when reproducing data recorded on the second recording layer 30, the intensity of the laser beam L reflected from the second recording layer 30 and emitted from the light incident surface 15a is detected. The recording layer 30 of the recording layer 30 needs to have sufficient reflectivity so that a high level reproduction signal can be obtained when the data recorded in the second recording layer 30 is reproduced. Further, when reproducing the data recorded on the third recording layer 40, the intensity of the laser beam L reflected from the third recording layer 40 and emitted from the light incident surface 15a is detected. The layer 40 needs to have sufficient reflectivity so that a high level reproduction signal can be obtained when the data recorded on the third recording layer 40 is reproduced.

  In the present embodiment, the second recording layer 30 and the third recording layer 40 are formed of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, respectively. And at least one metal element M selected from the group consisting of La and an element of S or O, such a material has a laser beam L having a wavelength λ of 380 nm to 450 nm. Is highly suitable as a material constituting the recording layer formed in the upper layer of the first recording layer 20.

  Furthermore, in the present embodiment, the thickness D2 of the second recording layer 30 and the thickness D3 of the third recording layer 40 are formed so as to satisfy the relationship D2> D3. When the second recording layer 30 and the third recording layer 40 are formed so that the recording layer is farther from the light incident surface 17a, the reflectance with respect to the laser beam L can be increased.

  As shown in FIG. 2, the third transparent intermediate layer 14 is formed on the surface of the third recording layer 40.

  The third transparent intermediate layer 14 serves to separate the third recording layer 40 from a waterproof layer 16 described later.

  Similarly to the first transparent intermediate layer 12 and the second transparent intermediate layer 13, the third transparent intermediate layer 14 is preferably formed using an ultraviolet curable acrylic resin.

  As shown in FIG. 2, a waterproof layer 16 is formed on the surface of the third transparent intermediate layer 14.

  The waterproof layer 16 functions as a second waterproof layer and prevents moisture from entering the third recording layer 40 and the second recording layer 30 from the outside of the optical recording medium 10 via the light transmission layer 17. Play a role to prevent.

The material for forming the waterproof layer 16 is not particularly limited as long as moisture can be prevented from entering the third recording layer 40 and the second recording layer 30. 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 Dielectric materials composed of oxides, nitrides, sulfides, fluorides, or composites containing at least one metal, and waterproof properties (low water absorption) such as polystyrene, polyolefin and vinylidene chloride It is preferable to form the waterproof layer 16 using a resin material. For example, it is particularly preferable to form the waterproof layer 16 with a material mainly composed of a dielectric made of ZnS · SiO ₂ .

  When the waterproof layer 16 is formed so as to include a dielectric material as a main component, the waterproof layer 16 is preferably formed to have a thickness of 20 nm to 150 nm, and preferably has a thickness of 30 nm to 120 nm. More preferably.

  When the thickness of the waterproof layer 16 is less than 20 nm, the waterproof properties required for the waterproof layer 16 cannot be satisfied, and when it exceeds 150 nm, the film formation time becomes long and the productivity may be deteriorated. .

  The waterproof layer 16 is used when data is recorded on the first recording layer 20, the second recording layer 30, or the third recording layer 40, or when the first recording layer 20, the second recording layer 30, or the first recording layer 20 is recorded. When the data recorded on the third recording layer 40 is reproduced, the laser beam L is transmitted therethrough. Therefore, it is necessary to have sufficient light transmittance.

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

  The light transmission layer 17 is a layer that transmits the laser beam L, and a light incident surface 17a is constituted by one surface thereof.

  When the third recording layer 40 and the waterproof layer 16 are formed apart from each other, 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

  The material for forming the light transmission layer 17 is not particularly limited, but is UV-cured in the same manner as the first transparent intermediate layer 12, the second transparent intermediate layer 13, and the third transparent intermediate layer 14. It is preferable to use a functional 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.

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

  3 to 6 are process diagrams showing a method for manufacturing the optical recording medium 10.

  First, as shown in FIG. 3, using the stamper 60, a support substrate 11 having grooves 11a and lands 11b on the surface is formed by injection molding.

  Next, as shown in FIG. 4, the reflective layer 21 and the second dielectric layer are formed on almost the entire surface of the support substrate 11 on which the grooves 11 a and lands 11 b are formed by vapor deposition such as sputtering. 22, a first recording film 23a, a second recording film 23b, and a first dielectric layer 24 are sequentially formed.

  Next, as shown in FIG. 5, an ultraviolet curable resin is applied on the surface of the first dielectric layer 24 by a spin coating method to form a coating film. The first transparent intermediate layer 12 having the grooves 12a and the lands 12b formed on the surface is formed by irradiating with ultraviolet rays through the stamper 61 in a state of covering.

  Next, as shown in FIG. 6, the second recording layer 30 is formed on the surface of the first transparent intermediate layer 12. Here, the second recording layer 30 is at least one metal selected from the group consisting of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and La. A case where the element is formed so as to include a single element of a metal element of Zn or La will be described as an example.

On the surface of the first transparent intermediate layer 12, a target containing ZnS.SiO ₂ or La.Si.O.N as a main component and at least one metal element selected from the group consisting of Mg, Al, and Ti are mainly used. A second recording layer 30 having a thickness of 15 nm to 50 nm is formed by sputtering using a target including the component.

Thus, sputtering is performed using a target containing ZnS · SiO ₂ or La · Si · O · N as a main component and a target containing as a main component at least one metal element selected from the group consisting of Mg, Al and Ti. When the second recording layer 30 is formed by the method, at least one metal element selected from the group consisting of Mg, Al, and Ti acts as a reducing agent in the film formation process of the second recording layer 30. As a result, the Zn or La metal element is present in a single form in the second recording layer 30.

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 second recording layer 30. 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 second recording layer 30 in a single form.

  In the present embodiment, when the second recording layer 30 contains Mg, the addition amount of Mg is preferably 18.5 atomic% to 33.7 atomic%, and more preferably 20 atomic% to 33. More preferably, it is 5 atomic%, and when Al is contained, the amount of Al added is preferably 11 atomic% to 40 atomic%, more preferably 18 atomic% to 32 atomic%, When Ti is contained, the addition amount of Ti is preferably 8 atomic% to 34 atomic%, and more preferably 10 atomic% to 26 atomic%.

  Next, an ultraviolet curable resin is applied onto the surface of the second recording layer 30 by a spin coating method to form a coating film, and the stamper 61 is applied with the stamper 61 covered on the surface of the coating film. Then, the second transparent intermediate layer 13 having the grooves 13a and lands 13b formed on the surface is formed by irradiating with ultraviolet rays.

  Next, the third recording layer 40 is formed on the surface of the second transparent intermediate layer 13 in the same manner as the second recording layer 30.

  Next, an ultraviolet curable resin is applied onto the surface of the third recording layer 40 by a spin coating method to form a coating film, and the coating film is irradiated with ultraviolet rays, whereby the third transparent intermediate layer is formed. 14 is formed.

  Next, the waterproof layer 16 is formed on the surface of the third transparent intermediate layer 14 by a vapor phase growth method using chemical species including the constituent elements of the waterproof layer 16. Examples of the vapor deposition method include a vacuum deposition method and a sputtering method.

  Further, as shown in FIG. 2, an ultraviolet curable resin is applied onto the surface of the waterproof layer 16 by a spin coating method to form a coating film, and the coating film is irradiated with ultraviolet rays to transmit light. Layer 17 is formed.

  Thus, the optical recording medium 10 is manufactured.

  As described above, according to the present embodiment, the reflective layer 21 and the second dielectric layer 22 as the first waterproof layer are provided between the support substrate 11 and the first recording layer 20, thereby transmitting light. Since the waterproof layer 16 as the second waterproof layer is provided between the layer 17 and the third recording layer 40, the support substrate 11 or the light transmission layer 17 is interposed from the outside of the optical recording medium 10. Since it is possible to prevent moisture from entering the first recording layer 20, the second recording layer 30, and the third recording layer 40, the first recording layer 20, the second recording layer 30, and the first recording layer The data recorded on the third recording layer 40 can be prevented from being deteriorated, or the characteristics of the first recording layer 20, the second recording layer 30, and the third recording layer 40 can be prevented from being altered, Therefore, it becomes possible to increase the reliability of the optical recording medium for long-term storage. .

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

  In the present embodiment, when data is recorded 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 17a of the light transmission layer 17, and the first recording layer. 20, any one of the second recording layer 30 and the third recording layer 40 is focused on the laser beam L.

  FIG. 7 shows a laser power control signal for controlling the power of the laser beam L when data is recorded on the first recording layer 20, the second recording layer 30 or the third recording layer 40 of the optical recording medium 10. It is a diagram which shows a pulse train pattern.

  As shown in FIG. 7, the pulse train pattern of the laser power control signal used to record data on the first recording layer 20, the second recording layer 30 or the third recording layer 40 of the optical recording medium 10 is: A level-modulated pulse is composed of three levels, ie, a level corresponding to the recording power Pw, a level corresponding to the intermediate power Pm, and a level corresponding to the base power Pb. 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.

  When data is recorded on the first recording layer 20, the power of the laser beam L is modulated in accordance with the laser power control signal having the pulse train pattern shown in FIG. 7, and thus the laser beam L whose power is modulated is modulated. Is focused on the first recording layer 20, and the light transmission layer 17, the waterproof layer 16, the third transparent intermediate layer 14, the third recording layer 40, the second transparent intermediate layer 13, and the second recording layer. 30, the first recording layer 20 is irradiated through the first transparent intermediate layer 12 and the first dielectric layer 24.

  FIG. 8 is a schematic cross-sectional view of the first recording layer 20 before data is recorded, and FIG. 9 is a schematic cross-sectional view of the first recording layer 20 after data is recorded.

  When the first recording layer 20 is irradiated with the laser beam L set at the recording power Pw, the first recording layer 20 is heated, and as shown in FIG. An element included as a component and an element included as a main component in the second recording film 23b are mixed to form a mixed region M. The mixed region M can be used as the recording mark M because the reflectance with respect to the laser beam L is greatly different from the other regions.

  In the present embodiment, the second recording layer 30 and the third recording layer 40 located above the first recording layer 20 are respectively composed of a simple element of Zn or La metal element, an element of S or O, and Therefore, the second recording layer 30 and the third recording layer 40 have a high light transmittance with respect to the laser beam L. Therefore, the laser beam L is When the light passes through the third recording layer 40 and the second recording layer 30, it is possible to minimize the reduction in the power of the laser beam L. Data can be recorded.

  On the other hand, even when data recorded on the first recording layer 20 is reproduced, the power of the laser beam L is minimized when passing through the third recording layer 40 and the second recording layer 30. In addition, when the laser beam L reflected by the first recording layer 20 passes through the second recording layer 30 and the third recording layer 40, the power of the laser beam L is reduced. Since it is possible to suppress the decrease to the minimum, the data recorded on the first recording layer 20 can be reproduced as desired.

  Furthermore, in this embodiment, since the reflective film 21 is formed between the first recording film 23a and the support substrate 11, the laser beam L reflected by the reflective film 21 and the first recording layer As a result, the difference in reflectance between before and after recording can be increased, so that data recorded on the L0 layer 20 is reproduced with high sensitivity. be able to.

  Further, when data is recorded on the second recording layer 30, the power of the laser beam L is modulated according to the laser power control signal having the pulse train pattern shown in FIG. 7, and thus the power is modulated. The laser beam L is focused on the second recording layer 30, and passes through the light transmission layer 17, the waterproof layer 16, the third transparent intermediate layer 14, the third recording layer 40, and the second transparent intermediate layer 13. The second recording layer 30 is irradiated.

  Thus, when the second recording layer 30 is irradiated with the laser beam L, the phase state of the second recording layer 30 changes and data is recorded on the second recording layer 30. Hereinafter, a specific recording mechanism will be described by taking as an example the case where the second recording layer 30 includes 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 second recording layer 30 is heated, and the second recording layer 30 is heated in the heated second recording layer 30 region. The elemental Zn or La metal element contained reacts with S or O to become ZnS or La ₂ O ₃ in the crystalline state, and further, amorphous that exists in the vicinity of the crystalline ZnS or La ₂ O ₃ Crystals of ZnS or La ₂ O ₃ in the state grow using ZnS or La ₂ O ₃ in the 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.

  Even when data is recorded on the third recording layer 40, similarly to the second recording layer 30, the third recording layer 40 is irradiated with a laser beam to record data.

  Here, the level of the recording power Pw of the laser beam L is set for each recording layer for recording data.

That is, when data is recorded on the first recording layer 20, the elements contained in the first recording film 23a as main components and the second recording film 23b are mainly irradiated by irradiating the laser beam L. The recording power Pw of the laser beam L is set to a level at which the elements contained as components are mixed and the mixed region M is reliably formed, and data is stored in the second recording layer 30 or the third recording layer 40. Is recorded, the Zn or La element and the S or O element contained in each of the second recording layer 30 and the third recording layer 40 are bonded by irradiating the laser beam L. Thus, the recording power Pw of the laser beam L is surely set to a level at which a ZnS or La ₂ O ₃ crystal is generated.

  The levels of the intermediate power Pm and the base power Pb are also set for each recording layer for recording data.

  That is, when data is recorded on the first recording layer 20, even when the laser beam L having the intermediate power Pm or the base power Pb is irradiated, the elements contained as the main component in the first recording film 23a are: The intermediate power Pm and the base power Pb are set to a level at which the elements contained as the main components in the second recording film 23b are not mixed, and data is stored in the second recording layer 30 or the third recording layer 40. When the laser beam L of the intermediate power Pm or the base power Pb is irradiated, a Zn or La metal element contained in each of the second recording layer 30 and the third recording layer 40, and The intermediate power Pm and the base power Pb are set to a level at which the element of S or O is not bonded.

  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 first recording layer 20, the second recording layer 30, or the third recording layer 40 of the optical recording medium 10.

  FIG. 10 is a schematic perspective view of an optical recording disk according to another preferred embodiment of the present invention, and FIG. 11 is a schematic enlarged sectional view of a portion indicated by B in FIG.

  As shown in FIG. 11, the optical recording medium 100 according to this embodiment includes a support substrate 11, a reflective layer 21, a second dielectric layer 22, a first recording layer 20, and a first dielectric. The body layer 24, the first transparent intermediate layer 12, the second recording layer 30, the second transparent intermediate layer 13, the third recording layer 40, the waterproof layer 50, and the light transmission layer 17 I have.

  In the present embodiment, as shown in FIG. 11, a waterproof layer 50 as a second waterproof layer is formed on the surface of the third recording layer 40, and the waterproof layer 50 is formed on the third recording layer 40. Adjacent to each other.

  Similar to the waterproof layer 16 shown in FIGS. 1 and 2, the waterproof layer 50 is formed from the outside of the optical recording medium 10 via the support substrate 11 or the light transmission layer 17, the first recording layer 20, and the second recording layer 20. This serves to prevent moisture from entering the recording layer 30 and the third recording layer 40.

  In the case where the waterproof layer 50 is formed adjacent to the third recording layer 40, the moisture is transferred to the first recording layer 20, the second recording layer 30, and the light through the support substrate 11 or the light transmission layer 17. In addition to being able to prevent intrusion into the third recording layer 40, it is possible to prevent moisture from entering into the second recording layer 30 and the third recording layer 40 through the side surface of the optical recording medium 100. Therefore, according to the present embodiment, it is possible to further improve the reliability of the optical recording medium for long-term storage.

  In the present embodiment, the waterproof layer 50 is used when data is recorded on the first recording layer 20, the second recording layer 30, and the third recording layer 40, or when the first recording layer 20 and the second recording layer 40 are recorded. When data recorded on the recording layer 30 and the third recording layer 40 is reproduced, the laser beam L is transmitted therethrough, and therefore it is necessary to have sufficient light transmittance.

  The waterproof layer 50 can be formed on the surface of the third recording layer 40 by a vapor phase growth method using chemical species containing the constituent elements of the waterproof layer 50. Examples of the vapor deposition method include a vacuum deposition method and a sputtering method.

  FIG. 12 is a schematic perspective view of an optical recording disk according to another preferred embodiment of the present invention, and FIG. 13 is a schematic enlarged sectional view of a portion indicated by C in FIG.

  As shown in FIG. 13, the optical recording disk 200 according to this embodiment includes a support substrate 11, a reflective layer 21, a second dielectric layer 22 of the first recording layer 20, and a first recording layer. 20, the first dielectric layer 24 of the first recording layer 20, the first transparent intermediate layer 12, the second dielectric layer 32 of the second recording layer 30, and the second recording layer 30. The first dielectric layer 33 of the second recording layer 30, the second transparent intermediate layer 13, the second dielectric layer 42 of the third recording layer 40, and the third recording layer 40. The first dielectric layer 43 of the third recording layer 40 and the light transmission layer 17 are provided.

  In the present embodiment, as shown in FIG. 13, the second dielectric layer 22 and the first dielectric layer are adjacent to the first recording layer 20 so as to sandwich the first recording layer 20. 24, and a second dielectric layer 32 and a first dielectric layer 33 are formed adjacent to the second recording layer 30 so as to sandwich the second recording layer 30, and a third recording layer is formed. A second dielectric layer 42 and a first dielectric layer 43 are formed adjacent to the third recording layer 40 so as to sandwich the layer 40.

  In the present embodiment, the second dielectric layer 22 to the first dielectric layer 43 function as a part of the recording layer. Among these dielectric layers, the second dielectric layer 22 and the first dielectric layer 43 In the dielectric layer 43, the first recording layer 20, the second recording layer 30, and the third recording layer 40 are formed from the outside of the optical recording medium 200 via the support substrate 11 or the light transmission layer 17. It also serves as a waterproof layer that prevents moisture from entering.

  In the present embodiment, the materials used to form the second dielectric layer 22 through the first dielectric layer 43 are the first recording layer 20, the second recording layer 30, and the third recording layer 40. It is not particularly limited as long as it is a dielectric material that can prevent moisture from entering and crystallizes. For example, an oxide, sulfide, nitride, or a combination thereof is used as a main component. Depending on the dielectric material, the second dielectric layer 22 to the first dielectric layer 43 can be formed.

More specifically, the second dielectric layer 22 to the first dielectric layer 43 are formed 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, or an oxide, nitride, sulfide, fluoride containing at least one metal selected from the group consisting of these metals, Alternatively, it is preferable that a dielectric material composed of these composites is included as a main component, for example, it is more preferable that ZnS · SiO ₂ is included as a main component, and the first dielectric layer 33, the second For the dielectric layer 32, the first dielectric layer 43, and the second dielectric layer 43, the metal elements contained in the adjacent second recording layer 30 and third recording layer 40 and the element S or O As a main component It is particularly preferable to include it.

  In the present embodiment, the first dielectric layer 24 to the first dielectric layer 43 excluding the second dielectric layer 22 are the first recording layer 20, the second recording layer 30, or the third recording layer. Layer through which the laser beam L is transmitted when data is recorded on the recording layer 40, or when data recorded on the first recording layer 20, the second recording layer 30 or the third recording layer 40 is reproduced. Therefore, it is necessary to have sufficient light transmittance.

  The second dielectric layer 22 to the first dielectric layer 43 may be formed of the same dielectric material, but may be formed of different dielectric materials.

  The second dielectric layer 22 to the first dielectric layer 43 are formed by a vapor phase growth method using chemical species including the constituent elements of the second dielectric layer 22 to the first dielectric layer 43. be able to. 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. 14 is a schematic cross-sectional view of the second dielectric layer 32, the second recording layer 30, and the first dielectric layer 33 before data is recorded, and FIG. 15 is a diagram after data is recorded. 4 is a schematic cross-sectional view of the second dielectric layer 32, the second recording layer 30, and the first dielectric layer 33. FIG.

  In the present embodiment, when data is recorded on the second recording layer 30 or the third recording layer 40 of the optical recording medium 200, the power is recorded in the same manner as the optical recording medium 10 shown in FIGS. Is irradiated to the second recording layer 30 or the third recording layer 40.

Thus, when the second recording layer 30 or the third recording layer 40 is irradiated with the laser beam L, the recording layer irradiated with the laser beam L is heated, and the optical recording medium shown in FIGS. 10, the single Zn or La metal element contained in the second recording layer 30 or the third recording layer 40 reacts with S or O in the region of the heated recording layer to react with the crystalline state. ZnS or La ₂ O ₃ in the crystalline state, and the amorphous ZnS or La ₂ O ₃ existing around the crystalline ZnS or La ₂ O ₃ is composed of the crystalline ZnS or La ₂ O ₃ as a nucleus. Crystal growth.

As a result, as shown in FIG. 15, a recording mark M is formed in which ZnS or La ₂ O ₃ , which is a compound of a single element of Zn or La metal element and S or O element, is crystallized.

  Further, in the present embodiment, the second recording layer 30 or the third recording layer 40 is irradiated with the laser beam L, and the recording mark M is formed on the second recording layer 30 or the third recording layer 40. When formed, the second dielectric layer 32 and the first dielectric layer 33 adjacent to the second recording layer 30 or the second dielectric layer 42 and the first dielectric layer adjacent to the third recording layer 40 are formed. As shown in FIG. 15, the dielectric material contained in one dielectric layer 43 is crystallized, and the second dielectric layer 32 and the first dielectric layer 33, or the second dielectric layer 42 and A crystallized region M ′ is formed in the first dielectric layer 43 adjacent to the recording mark M.

When the recording mark M is formed on the second recording layer 30 or the third recording layer 40 by irradiation with the laser beam L, the second dielectric layer 32 adjacent to the second recording layer 30 and the first The reason why the dielectric layer material included in the first dielectric layer 33 or the second dielectric layer 42 and the first dielectric layer 43 adjacent to the third recording layer 40 is crystallized is not necessarily clear. The second recording layer 30 or the third recording layer 40 is irradiated with the laser beam L, and the amorphous ZnS or La ₂ existing in the periphery with the crystalline ZnS or La ₂ O ₃ as the nucleus. The crystallization reaction for crystal growth of O ₃ is also transmitted to the second dielectric layer 32 and the first dielectric layer 33 or the second dielectric layer 42 and the first dielectric layer 43, and as a result. From the interface with the second recording layer 30, the second dielectric 32 toward the inside of the first dielectric layer 33 and from the interface with the third recording layer 40 toward the inside of the second dielectric layer 42 and the first dielectric layer 43. As the crystallization of the body material proceeds, a crystallization region M ′ is formed in the second dielectric layer 32 and the first dielectric layer 33 or in the second dielectric layer 42 and the first dielectric layer 43. I guess it was.

  Thus, in the present embodiment, the recording marks M are formed on the second recording layer 30 and the third recording layer 40, and the second dielectric layer 32 adjacent to the recording marks M and Since the crystallization region M ′ is formed in the region of the first dielectric layer 33 or the second dielectric layer 42 and the first dielectric layer 43, the recording mark M and the crystal The difference between the reflectivity of the region where the conversion region M ′ is formed and the reflectivity of other regions becomes large as a whole, and therefore, it becomes possible to obtain a reproduced signal having better signal characteristics.

  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 and having grooves and lands formed on the surface with a groove pitch of 0.32 μm was manufactured by an injection molding method.

Next, the polycarbonate substrate is set in a sputtering apparatus, and on the surface on which the grooves and lands are formed, a reflective layer containing an alloy of Ag, Pd and Cu as a main component and having a thickness of 100 nm, a mixture of ZnS and SiO ₂ A second dielectric layer of the first recording layer having a thickness of 39 nm, a thickness of 5 nm in which Cu is the main component and 23 atomic% Al and 13 atomic% Au are added. A first recording film having Si as a main component, a second recording film having a thickness of 5 nm, and a first recording having a mixture of ZnS and SiO ₂ as a main component and a thickness of 20 nm. A first dielectric layer was sequentially formed by sputtering.

  Next, a polycarbonate substrate having a reflection layer, a second dielectric layer of the first recording layer, a first recording layer, and a first dielectric layer of the first recording layer formed on the surface thereof is spin coated. While rotating the polycarbonate substrate, an ultraviolet curable acrylic resin is applied on the first dielectric layer of the first recording layer to form a coating film while rotating the polycarbonate substrate. A stamper on which grooves and lands are formed is placed on the surface of the 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. In addition, a first transparent intermediate layer having a thickness of 15 μm on which grooves and lands were formed was formed so that the groove pitch was 0.32 μm.

Next, the substrate on which the first transparent intermediate layer is formed is set in a sputtering apparatus, and a second recording layer having a thickness of 80 nm is formed by sputtering using a target made of ZnS · SiO ₂ . A dielectric layer was formed. Here, a ZnS / SiO ₂ mixed target having a molar ratio of 80:20 was used.

Next, the substrate on which the second dielectric layer of the second recording layer is formed is set in a sputtering apparatus, and a mixed target of ZnS and SiO _{2 and} a target made of Mg are used to form a 23 nm film by sputtering. A second recording layer having a thickness of 1 mm was formed. Here, a ZnS / SiO ₂ mixed target having a molar ratio of 80:20 was used.

As a result of measuring the composition of the second recording layer after forming the second recording layer, the contents of Zn, Si, Mg, O and S were 21.5 atomic%, 10.1 atomic%, and 20 respectively. 8 atomic%, 20.1 atomic%, and 27.5 atomic%. The addition amount of Zn, Si, Mg, O and S contained in the second recording layer was determined by using a fluorescent X-ray apparatus “RIX2000” (trade name) manufactured by Rigaku Denki Kogyo Co., Ltd., Rh tube, tube voltage = X-rays were generated at 50 kV and tube 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, on the surface of the second recording layer, using the same method as the formation of the second dielectric layer of the second recording layer, the first dielectric of the second recording layer having a thickness of 85 nm And forming a second transparent intermediate layer having a thickness of 15 μm on the surface of the first dielectric layer of the second recording layer using the same method as the formation of the first transparent intermediate layer. Formed.

  Then, on the surface of the second transparent intermediate layer, using the same method as the formation of the second dielectric layer of the second recording layer, the second dielectric of the third recording layer having a thickness of 80 nm. And forming a third recording layer having a thickness of 17 nm on the surface of the second dielectric layer of the third recording layer, using the same method as the formation of the second recording layer. And using the same method as the formation of the second dielectric layer of the second recording layer on the surface of the third recording layer, the first dielectric of the third recording layer having a thickness of 85 nm. A layer was formed.

  Then, an ultraviolet curable acrylic resin is applied on the surface of the first dielectric layer of the third recording layer by a spin coating method to form a coating film. A light transmission layer having a thickness of 5 mm 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., and data was recorded on the optical recording disk sample # 1 under the following conditions. .

  A blue laser beam having a wavelength of 405 nm is used as a recording laser beam, and an objective lens having an NA (numerical aperture) of 0.85 is used to collect the laser beam on the first recording layer through the light transmission layer. The first recording layer of the optical recording disk sample # 1 is recorded with a recording mark having a length of 2T and a recording mark having a length of 8T in the (1, 7) RLL modulation system under the following recording signal conditions. Formed.

  Further, the laser beam was condensed on the first recording layer through the light transmission layer, and data was recorded by randomly combining recording marks having a length of 2T to 8T.

  The laser power control signal for modulating the power of the laser beam uses the pulse train pattern shown in FIG. 7, the recording power Pw of the laser beam is set to 11 mW, the intermediate power Pm is set to 3.0 mW, and the base power Pb was set to 2.0 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 first recording layer of the optical recording disk sample # 1 is irradiated with a laser beam set at the reproduction power to perform the first recording. The data recorded on the track where the data is recorded on the tracks on both sides of the layer is reproduced, the reflectance of the part where the recording mark is not formed and the recording mark of 2T length is formed, and the recorded data The C / N ratio of the reproduction signal when reproducing data, the recording mark of 8T length, and the C / N ratio of reproduction signal when reproducing the recorded data, and the length of 2T to 8T These recording marks were randomly combined, and the clock jitter when the recorded data was reproduced was measured. Here, the reproduction power of the laser beam was 1.0 mW. At this time, the reproducing laser beam was used by changing the same laser power as that of the recording laser beam.

  Here, the reflectivity of the first recording layer is obtained by removing the reflection from the other layers stacked on the first recording layer from the reflectivity measured by irradiating the first recording layer with a laser beam. Similarly, in the reflectivity of the second recording layer and the third recording layer, the amount of reflection by other layers laminated on the second recording layer and the third recording layer is removed. Sought. For reflection by other layers, an optical disk having only one recording layer and an optical disk having two recording layers laminated via a transparent intermediate layer are prepared, and the reflection of the lower recording layer is prepared for each optical disk. The rate was determined by comparing the measured reflectivity of each optical disc. As a result, in the optical disc having two recording layers, the reflectance of the lower recording layer was measured. When the thickness of the transparent intermediate layer was 15 μm, 2% of the reflectance of the upper recording layer was noise. As a component, it was mixed in the reflectance of the recording layer on the lower layer side, and based on these results, the reflection by other layers in the optical disc having three recording layers was calculated.

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

  Further, the clock jitter was calculated by obtaining “fluctuation σ” of the reproduction signal by a time interval analyzer and by σ / Tw (Tw: one cycle of the clock). When measuring the clock jitter, a limit equalizer was used, and the jitter was measured at a time of 4 ms.

  The measurement results are shown in Table 1.

  Next, using the above-described optical recording medium evaluation apparatus, the laser beam is sequentially focused on each of the second recording layer and the third recording layer of the optical recording disk sample # 1 through the light transmission layer. In the (1, 7) RLL modulation method, a recording mark having a length of 2T and a recording mark having a length of 8T are respectively recorded on the second recording layer and the third recording layer of the optical recording disc sample # 1. Formed.

  Further, the laser beam was sequentially focused on each of the second recording layer and the third recording layer, and data was recorded by randomly combining recording marks having a length of 2T to 8T.

  The laser power control signal that modulates the power of the laser beam uses the pulse train pattern shown in FIG. 7, and the recording power of the laser beam is determined when data is recorded on the second recording layer and when the data is recorded on the third recording layer. In both cases, the intermediate power Pm and the base power Pb were set to 3.0 mW and 2.0 mW.

  Next, using the same optical recording medium evaluation apparatus, each of the second recording layer and the third recording layer of the optical recording disk sample # 1 is sequentially irradiated with a laser beam set at a reproduction power, and recording is performed. The reflectance of the part where the mark is not formed, the recording mark of 2T length is formed, the C / N ratio of the reproduction signal when the recorded data is reproduced, and the recording mark of 8T length is formed Then, the C / N ratio of the reproduction signal when the recorded data is reproduced, and the clock jitter when the recorded data is reproduced by randomly combining recording marks having a length of 2T to 8T, respectively. ,It was measured.

  When reproducing data, the data recorded on this track is targeted for a track sandwiched between two tracks on which data is recorded, as in the case of reproducing the data recorded on the first recording layer. Played.

  The measurement results are shown in Table 1.

次いで、記録層にデータが記録された光記録ディスクサンプル＃１を、温度８０℃、相対湿度８５％の環境下において、５０時間にわたり、保持して、保存試験を実行した。これは、通常の使用環境より高温、多湿な条件下で、光記録ディスクサンプル＃１を所定時間にわたって、保存することにより、実際の使用環境における長期間の保存後の光記録ディスクの性能を確認し、実際の使用環境における信頼性を確かめたものである。

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 80 ° 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, the reproduction power was sequentially set to the first recording layer, the second recording layer, and the third recording layer of the optical recording disc sample # 1 after the storage test. Irradiation with a laser beam, the reflectance of the portion where the recording mark is not formed, the recording mark of 2T length is formed, the C / N ratio of the reproduction signal when the recorded data is reproduced, and 8T When a recorded mark having a length is formed and the recorded data is reproduced by randomly combining the C / N ratio of the reproduced signal when the recorded data is reproduced and the recording mark having a length of 2T to 8T. Each clock jitter was measured.

  The measurement results are shown in Table 2.

表１および表２に示されるように、光記録ディスクサンプル＃１においては、第一の記録層、第二の記録層および第三の記録層のデータが記録されていない領域の反射率、２Ｔの長さの記録マークを形成して、記録したデータを再生したときの再生信号のＣ／Ｎ比、８Ｔの長さの記録マークを形成して、記録したデータを再生したのときの再生信号のＣ／Ｎ比、２Ｔないし８Ｔの長さの記録マークをランダムに組み合わせて、記録したデータを再生したときのクロックジッタが、保存試験の前後で、ほとんど、変化が認められず、長期間の保存に対する高い信頼性を有することが判明した。

As shown in Tables 1 and 2, in the optical recording disk sample # 1, the reflectance of the area in which the data of the first recording layer, the second recording layer, and the third recording layer are not recorded, 2T When a recorded mark is formed, a C / N ratio of a reproduced signal when the recorded data is reproduced, and a recorded mark having a length of 8T is formed, and a reproduced signal when the recorded data is reproduced The C / N ratio of 2T to 8T is a random combination of recording marks, and the recorded clock jitter is almost unchanged before and after the storage test. It was found to have high reliability for storage.

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

  In this embodiment, it is assumed that the metal layer M is included in the recording layer in a state where the presence 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 a part of the third recording layer of the three optical recording disk samples in the same manner as in Example 1. And recorded the data.

Next, for one of the three optical recording disk samples on which data was recorded, the light transmission layer was cut with a cutter and removed, and the first dielectric layer of the third recording layer was removed, The third recording layer is exposed, and a dielectric film having a thickness of 20 nm is formed on the exposed surface of the third recording layer (for example, Al ₂ O ₃ when the recording layer contains ZnS as a main component). A metal film (for example, Al) having a thickness of 100 nm was 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 third recording layer was exposed. .

  Next, in the optical recording disk sample in which the data is recorded, an energy spectrum is used for the area where the data of the third recording layer is recorded and the area where the data of the third recording layer is not recorded using an Auger spectrometer. Was measured. 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 disk samples is cut with a cutter, and the light transmission layer, the first dielectric layer of the third recording layer, and the third recording are recorded. Separate the light-transmitting layer, the first dielectric layer of the third recording layer, and the third recording layer using an ultraviolet curable resin and slide the light-transmitting layer in contact with the slide glass. Glued on 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 in the area where the data of the third recording layer was recorded and the area where the data of the third recording layer was not recorded, the data was not recorded. The region was found to have a light absorptance of 34%, while the region where data was recorded had 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 metal element M was found in the region of the third recording layer irradiated with the recording laser beam and the presence of the metal element M alone on the third recording layer. It was judged that the simple substance of was combined with the element X to produce a crystal of the compound.

  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 third recording layer in the cut section, a broad diffraction ring of ZnS was recognized in the area where data was not recorded, while in the area where data was recorded, ZnS A diffraction spot was observed. From these results, it was determined that ZnS crystallization was generated in the region of the third recording layer irradiated with the recording laser beam.

  The present invention is not limited to the above 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 media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 10 and 11, and FIGS. 12 and 13, the first waterproof layer is Although formed between the support substrate 11 and the first recording layer 20, the first waterproof layer is formed on the main surface of the support substrate 11 opposite to the first recording layer 20 side. Also good.

  In the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 10 and 11, and FIGS. 12 and 13, the reflective layer 21 is formed on the support substrate 11. The second dielectric layer 22 is provided, and the reflective layer 21 and the second dielectric layer 22 constitute the first waterproof layer. However, the present invention is not limited to this. The second dielectric layer 22 may be omitted, and the waterproof layer may be configured only by the reflective layer 21, or the reflective layer 21 may be omitted and the first waterproof layer may be configured only by the second dielectric layer 22. Also good.

  In the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 10 and 11, and FIGS. 12 and 13, the reflective layer 21 is formed on the support substrate 11. The second dielectric layer 22 is provided, and the reflective layer 21 and the second dielectric layer 22 constitute the first waterproof layer. The support substrate 11 is a resin having waterproof properties (water absorption). The support substrate 11 may be configured to function as the first waterproof layer by using polystyrene, polyolefin or the like. In this case, the reflective layer 21, the second dielectric layer 22 and the support substrate 11 may constitute the first waterproof layer, or the reflective layer 21 and the second dielectric layer 22 may be omitted. You may make it comprise a 1st waterproofing layer only with the support substrate 11. FIG.

  In the optical recording medium 200 according to the embodiment shown in FIGS. 12 and 13, the second recording layer 30 and the third recording layer 40 are formed so as to be sandwiched between dielectric layers, respectively. However, only one of the second recording layer 30 and the third recording layer 40 may be formed so as to be sandwiched between the dielectric layers.

  In the optical recording medium 200 according to the embodiment shown in FIGS. 12 and 13, the second dielectric layer 32 of the second recording layer 30 and the first dielectric layer of the second recording layer 30 are used. 33 is formed adjacent to the second recording layer 30 so as to sandwich the second recording layer 30, but only the first dielectric layer 33 of the second recording layer 30 is the second recording layer. The crystallization region M ′ may be formed in a dielectric layer formed adjacent to the layer 30 and adjacent to the second recording layer 30. Similarly, in the first dielectric layer 43 of the third recording layer 40 and the first dielectric layer 43 of the third recording layer 40, only the first dielectric layer 43 of the third recording layer 40 is adjacent to the third recording layer 40. The crystallized region M ′ may be formed in the dielectric layer formed adjacent to the third recording layer 40.

  In the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 10 and 11, and FIGS. 12 and 13, the second recording layer 20 other than the first recording layer 20 is used. The recording layer 30 and the third recording layer 40 are each selected from the group consisting of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and La. An element of S or O that forms a crystal of a compound with the metal element M by being irradiated with a recording laser beam and at least one kind of the element of the metal element M, However, the present invention is not limited to this, and at least one of the second recording layer 30 and the third recording layer 40 is made of Ni, Cu, Si, Ti, Ge. , Zr, Nb, Mo, I , Sn, W, Pb, Bi, Zn, and La, and at least one metal element M selected from the group consisting of Sn and W is irradiated with a recording laser beam so that the metal element M is bonded to the metal element. And an S or O element that forms a crystal of a compound with the element M.

Further, in the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 10 and 11, and FIGS. 12 and 13, ZnS · SiO ₂ or La · Si · O is used. The second recording layer 30 and the third layer are formed by sputtering using a target containing 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. However, as a result of film formation, the second recording layer 30 and the third recording layer 40 are irradiated with a single element of a metal element M of Zn or La and a recording laser beam. Accordingly, it is sufficient that the metal element M is bonded to a simple substance of the metal element M to form a crystal of a compound with the metal element M, and can contain an element of S or O. By using a target containing nS 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, the second recording layer 30 and the third recording layer are formed by sputtering. The recording layer 40 can also be formed.

  In the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 10 and 11, and FIGS. 12 and 13, the second recording layer 30 and the third recording layer 30 are provided. In order to include a single element of Zn or La metal element in the recording layer 40, a target containing at least one metal element selected from the group consisting of Mg, Al and Ti as a main component is used as a reducing agent. The recording layer 30 and the third recording layer 40 are formed. However, the present invention is not limited to this, and instead of a target containing at least one metal element selected from the group consisting of Mg, Al, and Ti as a main component. Then, the second recording layer 30 and the third recording layer 40 are formed by sputtering using a target containing Zn or La as a main component, and the second recording layer 0 and the third recording layer 40, may be contained a single metal element Zn or La.

  In the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 10 and 11, and FIGS. 12 and 13, the first recording layer 20 is made of Cu. The first recording film 23a including the main component and the second recording film 23b including Si as the main component are formed. The first recording layer 20 includes the first recording layer 20 including Cu as the main component. It is not always necessary to form one recording film 23a and a second recording film 23b containing Si as a main component, and the first recording layer 20 is made of a single metal element M of Zn or La. And a recording laser beam, so as to combine with a simple substance of the metal element M to form a crystal of a compound with the metal element M, and to contain an element of S or O. It can also be formed.

  Further, in the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 10 and 11, and FIGS. 12 and 13, the substrate 11, the light transmission layer 17, Three recording layers formed between the substrate 11 and the light transmission layer 17, the first recording layer 20, the second recording layer 30, and the third recording layer 40 are provided. The present invention is not limited to an optical recording medium having a recording layer, and can be widely applied to an optical recording medium having two or more recording layers.

  In the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 1 and 2, 10 and 11, and FIGS. 12 and 13, the first recording layer 20 is made of Cu. The first recording film 23a including the main component and the second recording film 23b including Si as the main component are configured to include the element included in the first recording film 23a as the main component, The recording film 23b is composed of a write-once recording layer in which data is recorded by mixing elements contained as main components. The first recording layer 20 is, for example, a read-only recording layer. There may be. In this case, the recording layer as the first recording layer is not particularly provided, and the support substrate 11 or the first transparent intermediate layer 12 functions as the lowermost recording layer, and the support substrate 11 or Pits are formed on the surface of the first transparent intermediate layer 12, and data is recorded by the pits.

  1 and 2, 4 and 5, and the optical recording media 10, 100, and 200 according to the embodiments shown in FIGS. 6 and 7 include the light transmission layer 17. 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, 10 and 11, and FIGS. 12 and 13, the laser beam L passes through the light transmission layer 17. In the present invention, the first recording layer 20 and the second recording layer 30 are irradiated. However, in the present invention, a light-transmitting substrate having a thickness of about 0.6 mm, The present invention can also be applied to a DVD-type optical recording medium having a dummy substrate having a thickness of 6 mm and two or more recording layers between the light-transmitting substrate and the 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 view of a portion indicated by A in FIG. FIG. 3 is a process diagram showing a method for manufacturing an optical recording medium according to a preferred embodiment of the present invention. FIG. 4 is a process diagram showing a method for manufacturing an optical recording medium according to a preferred embodiment of the present invention. FIG. 5 is a process diagram showing a method for manufacturing an optical recording medium according to a preferred embodiment of the present invention. FIG. 6 is a process diagram showing a method for manufacturing an optical recording medium according to a preferred embodiment of the present invention. FIG. 7 is a diagram showing a pulse train pattern of a laser power control signal for controlling the power of the laser beam L when data is recorded on the optical recording medium 10. FIG. 8 is a schematic cross-sectional view of the first recording layer 20 before data is recorded. FIG. 9 is a schematic cross-sectional view of the first recording layer 20 after data is recorded. FIG. 10 is a schematic perspective view of an optical recording medium 100 according to another preferred embodiment of the present invention. FIG. 11 is a schematic enlarged cross-sectional view of a portion indicated by B in FIG. FIG. 12 is a schematic perspective view of an optical recording medium 200 according to another preferred embodiment of the present invention. FIG. 13 is a schematic enlarged cross-sectional view of a portion indicated by C in FIG. FIG. 14 is a schematic cross-sectional view of the second dielectric layer 32, the second recording layer 30, and the first dielectric layer 33 before data is recorded. FIG. 15 is a schematic cross-sectional view of the second dielectric layer 32, the second recording layer 30, and the first dielectric layer 33 after data is recorded.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical recording medium 11 Board | substrate 11a Groove 11b Land 12 First transparent intermediate layer 12a Groove 12b Land 13 Second transparent intermediate layer 13a Groove 13b Land 14 Third transparent intermediate layer 14a Groove 14b Land 16 Waterproof layer 17 Light transmission layer 20 First recording layer 21 Reflective layer 22 Second dielectric layer 23a First recording film 23b Second recording film 24 First dielectric layer 30 Second recording layer 32 Second dielectric layer 33 First One dielectric layer 40 Third recording layer 42 Second dielectric layer 43 First dielectric layer 50 Waterproof layer 60 Stamper 61 Stamper 100 Optical recording medium 200 Optical recording medium

Claims (8)

A first waterproof layer, a second waterproof layer, and a plurality of recording layers formed between the first waterproof layer and the second waterproof layer, of the plurality of recording layers At least one recording layer is a simple substance 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. And an element X that combines with the simple substance of the metal element M to form a crystal of a compound with the metal element M when irradiated with a recording laser beam. . The optical recording medium according to claim 1, wherein at least one of the first waterproof layer and the second waterproof layer is formed adjacent to the recording layer. The recording layer includes at least one dielectric layer formed adjacent to at least one recording layer of the plurality of recording layers, and when the recording laser beam is irradiated, 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. The optical recording medium according to claim 1. The optical recording medium according to any one of claims 1 to 3, wherein the element X is an element of S or O. The recording layer containing the simple substance of the metal element M and the element X further contains at least one metal element selected from the group consisting of Mg, Al, and Ti. Optical recording media. Among the plurality of recording layers, the recording layer farthest from the light incident surface of the laser beam has a first recording film containing Cu as a main component and a second recording film containing Si as a main component. The optical recording medium according to any one of claims 1 to 5, wherein: The reflective layer for reflecting the laser beam is provided, and a recording layer farthest from the light incident surface of the laser beam is formed between the reflective layer and the light incident surface of the laser beam. 7. The optical recording medium according to any one of 1 to 6. The light according to any one of claims 1 to 7, wherein the plurality of recording layers are configured to be able to record and reproduce data using a laser beam having a wavelength of 380 nm to 450 nm. recoding media.

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