JP2004327016A - Optical recording disc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a jitter at the time of data reading within a desired range, suppress occurrence of an error at the time of data reading, and maintain a push-pull signal level at or above a desired value. To provide an optical recording disk capable of performing tracking control as desired.
SOLUTION: A support substrate 2, a groove G and a land L alternately formed on one main surface of the support substrate, and a recording layer formed on one main surface of the support substrate on which the groove and land are formed are formed. An optical recording disk 1 comprising a layer 7 and a light transmitting layer 9 formed on a recording layer, wherein each groove has a depth Gd of 15 nm or more and 25 nm or less, and a half width Gw of the groove is 150 nm. An optical recording disk in which grooves and lands are formed to have a thickness of 230 nm or less and the recording layer contains an inorganic element.
[Selection] Figure 2

Description

  The present invention relates to an optical recording disk, more specifically, it is possible to suppress the jitter at the time of data reading within a desired range, it is possible to suppress the occurrence of errors at the time of data reading, The present invention relates to an optical recording disk capable of holding a push-pull signal level at or above a desired value and performing tracking control as desired.

  In recent years, optical recording disks represented by CDs and DVDs have been widely used as recording media for recording large volumes of digital data.

  These optical recording discs are so-called ROM-type optical discs of a type in which data cannot be additionally written or rewritten, such as a CD-ROM or a DVD-ROM, and data can be additionally written, such as a CD-R or a DVD-R. However, data can be broadly classified into so-called write-once optical disks of a type in which data cannot be rewritten, and so-called rewritable optical disks of a type in which data can be rewritten, such as CD-RW and DVD-RW.

  As is widely known, in a ROM type optical disk, data is generally recorded by pre-pits formed on a substrate in a manufacturing stage. In a rewritable type optical disk, for example, a material of a recording layer is used. Generally, a phase change material is used, and data is generally recorded using a change in optical characteristics based on a change in the phase state.

  On the other hand, in a write-once optical disc, an organic dye such as a cyanine dye, a phthalocyanine dye, or an azo dye is used as a material of a recording layer, and a chemical change (in some cases, a physical change, In general, data is recorded by utilizing a change in optical characteristics based on the above-described data transformation.

  Further, a blue laser beam having a short wavelength of 400 nm to 430 nm is used as a laser beam to be irradiated for recording / reproduction so that large-capacity data can be recorded and reproduced at high density. A lens having a large numerical aperture (NA) is used as a lens of the recording optical system and the reproducing optical system, and a laser beam is irradiated from a side opposite to a substrate formed of polycarbonate or the like. A next-generation optical recording disc provided with a light transmitting layer has been proposed.

  In such a next-generation optical recording disk, in order to increase the recording capacity, it is required that the track pitch be reduced to 1/2 or less of that of DVD, that is, 0.25 μm to 0.34 μm.

  However, when the track pitch is reduced as described above, if the grooves and lands are not formed in a desired shape, jitter at the time of reading data increases, errors easily occur, and sufficient There was a problem that tracking control could not be performed.

  Therefore, according to the present invention, the jitter at the time of data reading can be suppressed within a desired range, the occurrence of an error at the time of data reading can be suppressed, and the push-pull signal level is maintained at a desired value or more. It is an object of the present invention to provide an optical recording disk capable of performing tracking control as desired.

  The inventor of the present invention has conducted intensive studies in order to achieve the object of the present invention. As a result, a supporting substrate, and grooves and lands alternately formed on one main surface of the supporting substrate are formed. An optical recording disk formed on one main surface of the support substrate and having an optical functional layer including at least one recording layer, and a light transmitting layer formed on the optical functional layer, By forming the groove and the land so that the groove depth Gd is 15 nm or more and 25 nm or less, and the half width Gw of the groove is 150 nm or more and 230 nm or less, the jitter at the time of reading data falls within a desired range. It is possible to suppress the occurrence of errors when reading data, and to keep the push-pull signal level at or above a desired value. It can be found that it is possible desired as in, for tracking control.

  Therefore, the object of the present invention is to provide a supporting substrate, grooves and lands alternately formed on one main surface of the supporting substrate, and one main surface of the supporting substrate on which the grooves and lands are formed. An optical recording disk comprising: an optical functional layer formed on a surface and including at least one recording layer; and a light transmitting layer formed on the optical functional layer, wherein a depth Gd of each groove is provided. Is not less than 15 nm and not more than 25 nm, and the groove and the land are formed such that the half width Gw of the groove is not less than 150 nm and not more than 230 nm, and the at least one recording layer contains an inorganic element. Achieved by the optical recording disk characterized.

  In the present invention, the main surface refers to a surface having a larger area than other surfaces.

  In the present invention, it is preferable that the optical recording disk is formed by a light having a wavelength of 400 nm to 430 nm through an objective lens having a numerical aperture (NA) of 0.8 to 0.9 and the light transmitting layer through an optical lens. The data can be recorded and reproduced at a track pitch of from 0.40 μm to 0.40 μm.

  In a preferred embodiment of the present invention, the groove has a substantially trapezoidal cross section, and the land has a substantially trapezoidal cross section.

  According to the study of the present inventor, by forming the groove and the land so that the groove has a substantially trapezoidal cross section and the land has a substantially trapezoidal cross section, the jitter of the reproduced data is sufficiently low, It has been found that it can be suppressed.

  In the present invention, the phrase that the groove has a substantially trapezoidal cross section means that not only when the top surface and the side surface of the groove are formed by a substantially flat surface, but also when the top surface and the side surface of the groove are formed by a curved surface. When the land has a substantially trapezoidal cross-section, not only when the top surface and the side surface of the land are formed by a substantially flat surface, but also when the top surface and the side surface of the land are formed by a curved surface It includes the case where it is formed.

  In a further preferred aspect of the present invention, the grooves and the lands are arranged such that the angle θ of the inclined surface between each of the grooves and the adjacent lands to the support substrate is 12 ° or more and 30 ° or less. Is formed.

  According to the study of the present inventor, by forming the groove and the land such that the angle θ of the inclined surface between each groove and the adjacent land to the support substrate is 12 ° or more and 30 ° or less, the reproduction is performed. It has been found that the jitter of the obtained data can be suppressed sufficiently low.

  In a further preferred aspect of the present invention, the groove and the land are arranged such that the angle θ of the inclined surface between each groove and the adjacent land to the support substrate is 12 ° or more and 25 ° or less. Is formed.

  In a preferred embodiment of the present invention, the groove and the land are formed such that a wobble amount Wob is ± 7 nm or more.

  According to the research of the present inventors, it is possible to improve the C / N ratio between a wobble signal and noise by forming a groove and a land so that the wobble amount Wob becomes ± 7 nm or more. Have been found.

  In a further preferred aspect of the present invention, the groove and the land are formed such that the wobble amount Wob is ± 7 nm to ± 25 nm.

  According to the study of the present inventor, by forming grooves and lands so that the wobble amount Wob is ± 7 nm to ± 25 nm, the wobble signal and noise can be kept at a low value while maintaining the residual tracking error at a low value. It has been found that it is possible to improve the C / N ratio.

  In a preferred embodiment of the present invention, the at least one recording layer contains, as a main component, one kind of element selected from the group consisting of Si, Ge, Sn, Mg, C, Al, Zn, In, Cu, Ti and Bi. And a first recording film that is provided in the vicinity of the first recording film and is selected from the group consisting of Cu, Al, Zn, Ag, Ti, and Si, and includes an element included in the first recording film. And a second recording film containing a different element as a main component.

  The present inventors have conducted intensive studies in order to improve the recording sensitivity of an optical recording disk and reduce the noise level of a reproduced signal, and as a result, have found that Si, Ge, Sn, Mg, C, Al, Zn, In, and Cu , Ti and Bi, a first recording film containing, as a main component, one kind of element selected from the group consisting of Cu, Al, Zn, Ag, Ti, and Si provided near the first recording film. When the recording film is formed by a second recording film selected from the group and containing, as a main component, an element different from the element contained in the first recording film, the data is formed using a laser beam. When recording, a laser beam mixes elements contained as a main component in the first recording film with elements contained as a main component in the second recording film to form a recording mark. And greatly change the reflectivity Is possible, and the element contained as a main component in the first recording film and the element contained as a main component in the second recording film are mixed to form an area in which a recording mark is formed. By utilizing the large difference between the reflectance and the reflectance of the blank area where the recording mark is not formed, data can be recorded with good sensitivity, and the noise level in the reproduced signal is reduced. It has been found that the C / N ratio can be improved.

  In the present specification, the phrase “the first recording film contains an element as a main component” means that among the elements contained in the first recording film, the content of the element is the largest, and the second recording film "Contains an element as a main component" means that among the elements contained in the second recording film, the content of the element is the largest.

  In the present invention, the second recording film, when irradiated with a laser beam, contains an element contained as a main component in the first recording film and a main component in the second recording film. It is sufficient that the second recording film is in contact with the first recording film as long as it is located near the first recording film so that a region in which elements are mixed is formed. Alternatively, one or more other layers such as a dielectric layer may be interposed between the first recording film and the second recording film.

  When a laser beam is irradiated, a region where an element contained as a main component in the first recording film and an element contained as a main component in the second recording film are mixed, and a recording mark is formed. Although the reason why is formed is not necessarily clear, when the laser beam is irradiated, the element contained in the first recording film as a main component and the element contained in the second recording film as a main component are A region in which an element that is partially or entirely melted or diffused and contained as a main component in the first recording film and an element contained as a main component in the second recording film is mixed. It is presumed to be formed.

  In this way, the element contained as a main component in the first recording film and the element contained as a main component in the second recording film are mixed to reproduce an area where a recording mark is formed. Since the reflectance with respect to the laser beam is significantly different from the reflectance with respect to the laser beam for reproducing the blank area, recorded data can be reproduced with high sensitivity by utilizing the large difference in reflectance.

  In another preferred embodiment of the present invention, the optically functional layer comprises a plurality of recording layers, and at least one recording layer different from the recording layer farthest from the light transmitting layer is formed of Si, Ge, Sn, Mg. , C, Al, Zn, In, Cu, Ti and Bi, a first recording film containing, as a main component, one kind of element selected from the group consisting of: Cu, Al , Zn, Ag, Ti, and Si, and a second recording film mainly containing an element different from the element contained in the first recording film.

  When the optical functional layer of the optical recording disk has a plurality of recording layers, a recording layer different from the recording layer farthest from the light transmitting layer records data on the recording layer farthest from the light transmitting layer, When data is reproduced from the recording layer farthest from the light transmitting layer, since the laser beam is transmitted, the light transmittance of the region where the recording mark of the recording layer different from the recording layer farthest from the light transmitting layer is formed, If the difference in the light transmittance of the blank area where the recording mark is not formed is large, when data is recorded on the recording layer farthest from the light transmitting layer, it is different from the recording layer farthest from the light transmitting layer through which the laser beam passes. Depending on whether the area of the different recording layer is the area where the recording mark is formed or the blank area, the light amount of the laser beam applied to the recording layer farthest from the light transmitting layer greatly changes and the light transmitting layer When data is reproduced from the recording layer furthest from the light transmitting layer, the light amount of the laser beam reflected by the recording layer farthest from the light transmitting layer and transmitted through the recording layer different from the recording layer farthest from the light transmitting layer to be detected. Is greatly changed. As a result, the light transmitting layer differs depending on whether the recording layer area different from the recording layer farthest from the light transmitting layer through which the laser beam passes is the area where the recording mark is formed or the blank area. There is a problem that the recording characteristics for the recording layer furthest from the recording layer and the amplitude of the signal reproduced from the recording layer farthest from the light transmitting layer greatly change.

  In particular, when reproducing data recorded on the recording layer furthest from the light transmitting layer, a recording mark was formed in a region of the recording layer different from the recording layer farthest from the light transmitting layer through which the laser beam LB passes. When the boundary between the region and the blank region is included, the reflectance distribution in the spot of the laser beam is not constant, so that the data recorded on the recording layer furthest from the light transmitting layer can be recorded as desired. It is impossible to regenerate.

  The present inventor has conducted intensive studies to solve such a problem, and as a result, has found that Si, Ge, Sn, Mg, C, Al, Zn, In, Cu, One kind of element selected from the group consisting of Ti and Bi, and the first recording film selected from the group consisting of Cu, Al, Zn, Ag, Ti and Si contained as main components in the second recording film; Are mixed with an element different from the element contained in the first recording film and the second recording film in terms of light transmittance to a laser beam having a wavelength of 400 nm to 430 nm in the region of the formed recording mark. The difference between the light transmittance of the blank region and the laser beam LB having a wavelength of 400 to 430 nm is 4% or less, and the difference between the light transmittance of the region where the recording mark is formed and the light transmittance of the blank region is sufficient. Small I found the door.

  Therefore, according to another preferred embodiment of the present invention, when data is recorded in at least one recording layer different from the recording layer farthest from the light transmitting layer, the main component is applied to the first recording film by the laser beam. Is mixed with the element contained as a main component in the second recording film, a recording mark is formed, the reflectance can be largely changed, and the data can be obtained with good sensitivity. Recording becomes possible, and the difference in light transmittance between a region where a recording mark is formed and a blank region with respect to a laser beam having a wavelength of 400 nm to 430 nm becomes 4% or less. By irradiating a laser beam having a wavelength of 430 nm, data is recorded on the recording layer farthest from the light transmitting layer, and data is reproduced from the recording layer farthest from the light transmitting layer. In this case, even when the area of the recording layer through which the laser beam passes includes the boundary between the area where the recording mark is formed and the blank area, the data is stored in the recording layer farthest from the light transmitting layer as desired. And data can be reproduced from the recording layer farthest from the light transmitting layer.

  In the present invention, preferably, the second recording film is formed so as to be in contact with the first recording film.

  In the present invention, in addition to the first recording film and the second recording film, one or more of Si, Ge, Sn, Mg, C, Al, Zn, In, A recording film containing, as a main component, one kind of element selected from the group consisting of Cu, Ti, and Bi, or a first film selected from the group consisting of one or more of Cu, Al, Zn, Ag, Ti, and Si. A recording film containing as a main component an element different from the elements contained in the recording film may be provided.

  In a preferred embodiment of the present invention, the second recording film includes an element selected from the group consisting of Cu, Al, Zn, Ag, Mg, Sn, Au, Ti and Pd. At least one element different from the element contained as the main component is added.

  According to a preferred embodiment of the present invention, it is possible to improve the storage reliability and the recording sensitivity of an optical recording disk.

  In a further preferred aspect of the present invention, the second recording film includes an element selected from the group consisting of Al, Zn, Sn and Au, and an element contained as a main component in the second recording film. At least one different element is added.

    According to a further preferred embodiment of the present invention, the stability of the second recording film against oxidation or sulfidation can be greatly improved, and the second recording film is caused by corrosion of an element contained as a main component in the second recording film. This makes it possible to effectively prevent poor appearance of the optical recording disk, such as peeling of the second recording film, and changes in the reflectance of the optical recording disk after long-term storage.

  In a preferred embodiment of the present invention, the first recording film further includes an element selected from the group consisting of Mg, Al, Cu, Ag, and Au and contained as a main component in the first recording film. One or more elements different from the above are added.

  According to the preferred embodiment of the present invention, it is possible to further improve the recording sensitivity of the optical recording disk.

  In the present invention, more preferably, the first recording film contains, as a main component, an element selected from the group consisting of Si, Ge, Sn, Mg, and Al, and further preferably, it comprises Si, Ge, and Sn. It contains an element selected from the group as a main component.

  When the first recording film contains, as a main component, an element selected from the group consisting of Si, Ge, Sn, Mg, and Al, it is possible to further improve the C / N ratio of the reproduced signal. .

  In the present invention, preferably, the second recording film contains Cu as a main component.

  When a second recording film containing Cu as a main component is formed by a vapor deposition method such as a vacuum evaporation method or a sputtering method, the surface smoothness of the second recording film is extremely high. As a result, the initial recording characteristics can be improved. As described above, since the optical recording disk according to the present invention has excellent surface smoothness of the recording layer, the recording characteristic when recording data is greatly improved, especially when the spot of the laser beam is very small. can do. Further, since Cu is very inexpensive, the material cost of the optical recording disk can be reduced.

  In another preferred embodiment of the present invention, the optically functional layer includes a plurality of recording layers stacked at least with an intermediate layer interposed, and a recording layer farthest from a light transmitting layer among the plurality of recording layers. At least one recording layer different from the layer 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. M and an element X that is combined with the metal M by being irradiated with a recording laser beam to form a crystal of a compound with the metal M.

  According to the study of the present inventor, at least one of the plurality of recording layers different from the recording layer farthest from the light transmitting layer is composed of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, At least one metal M selected from the group consisting of In, Sn, W, Pb, Bi, Zn, and La, and by being irradiated with a recording laser beam, combined with the metal M, It has been found that the recording layer has a sufficient light transmittance with respect to a laser beam when it is configured to contain the element X that forms a crystal of the compound .

  Therefore, according to another preferred embodiment of the present invention, before the laser beam reaches the recording layer farthest from the light transmitting layer, it is possible to minimize the decrease in the power of the laser beam, Data can be recorded on the recording layer furthest from the light transmitting layer as desired, while data recorded on the recording layer farthest from the light transmitting layer can also be reproduced from the light transmitting layer. Since the laser beam reflected by the farthest recording layer reaches the light incident surface, a decrease in the power of the laser beam can be minimized, so that the data recorded on the recording layer farthest from the light transmitting layer can be minimized. Can be reproduced as desired.

  According to another preferred embodiment of the present invention, a recording layer containing a metal M and an element X is irradiated with a laser beam for recording to combine the metal M and the element X to generate a compound crystal. Thereby, since it is configured to record data, it is possible to increase the difference in the reflectance of the laser beam between the region where the compound of the metal M and the element X is crystallized and the other region, Therefore, data can be recorded on the recording layers other than the recording layer farthest from the light transmission layer as well as the recording layer farthest from the light transmission layer, and the recorded data can be reproduced as desired.

  In a further preferred aspect of the present invention, among the plurality of recording layers, all the recording layers other than the recording layer farthest from the laser beam light transmitting layer include Ni, Cu, Si, Ti, Ge, Zr, and Nb. , Mo, In, Sn, W, Pb, Bi, Zn, and at least one metal selected from the group consisting of Zn and La, by being irradiated with a recording laser beam, combined with the metal M, It is formed so as to include a metal M and an element X that forms a crystal of a compound, and to be thinner as it is closer to the light transmitting layer of the laser beam.

  According to a further preferred embodiment of the present invention, the light transmittance of the recording layer different from the recording layer farthest from the light transmitting layer of the laser beam can be further improved as a whole. The data recorded on the recording layer furthest from the light transmitting layer can be reproduced as desired on the recording layer furthest from the light transmitting layer.

  According to the study of the present inventor, among the plurality of recording layers, all of the recording layers other than the recording layer farthest from the laser beam transmission layer are made of Ni, Cu, Si, Ti, Ge, Zr, and Nb. , Mo, In, Sn, W, Pb, Bi, Zn, and at least one metal M selected from the group consisting of La and a laser beam for recording are irradiated to combine with the metal M to form the metal M And the element X which forms a crystal of a compound of the formula (1), and when the layer is formed so as to be thinner as it is closer to the light transmitting layer, and as the distance from the light transmitting layer increases, the recording layer reflects the laser beam. The rate has been found to be high, so that data can be reproduced as desired from recording layers other than the recording layer farthest from the light transmitting layer of the laser beam.

  In a further preferred embodiment of the present invention, the optically functional layer comprises a first recording layer, a second recording layer, and a third recording layer in this order from the substrate side, Has a thickness of 15 nm to 50 nm, and the ratio of the thickness of the third recording layer to the thickness of the second recording layer is 0.40 to 0.70, A first recording layer, the second recording layer, and the third recording layer are formed.

  According to the study of the present inventor, the optical functional layer includes, from the substrate side, a first recording layer, a second recording layer, and a third recording layer in this order, and the second recording layer is , 15 nm to 50 nm, and the first recording layer and the second recording layer are arranged such that the ratio of the thickness of the third recording layer to the thickness of the second recording layer is 0.40 to 0.70. When the second recording layer and the third recording layer are formed, the amount of the laser beam absorbed by the second recording layer is substantially equal to the amount of the laser beam absorbed by the third recording layer. And it has been found that the laser beam absorptivity of the second recording layer and the third recording layer can be set to a sufficiently high level, ie, 10% to 30%, According to a further preferred embodiment of the present invention, the second recording layer and the third recording layer By irradiating the recording laser beam power, as desired, it is possible to record the data.

  According to the study of the present inventor, the optical functional layer comprises, from the substrate side, a first recording layer, a second recording layer, and a third recording layer, in this order, the second recording layer The first recording layer such that the layer has a thickness between 15 nm and 50 nm and the ratio of the thickness of the third recording layer to the thickness of the second recording layer is between 0.40 and 0.70. When the second recording layer and the third recording layer are formed, the reflectance of the second recording layer with respect to the laser beam is substantially equal to the reflectance of the third recording layer with respect to the laser beam. And it has been found that the reflectivity of each of them can be sufficiently high, and therefore, according to a further preferred embodiment of the present invention, both of the second recording layer and the third recording layer It is possible to reproduce data from the recording layer as desired.

  In the present invention, more preferably, the second recording layer and the third recording layer are so set that the ratio of the thickness of the third recording layer to the thickness of the second recording layer is 0.46 to 0.69. The second recording layer and the third recording layer are most preferably formed such that the ratio of the thickness of the third recording layer to the thickness of the second recording layer is 0.50 to 0.63. A recording layer is formed.

  In a further preferred embodiment of the present invention, the optical functional layer, from the substrate side, the first recording layer, the second recording layer, the third recording layer and the fourth recording layer, in this order Wherein the second recording layer has a thickness of 20 nm to 50 nm, and the ratio of the thickness of the third recording layer to the thickness of the second recording layer is 0.48 to 0.93; The first recording layer, the second recording layer, and the third recording layer so that the ratio of the thickness of the fourth recording layer to the thickness of the second recording layer is 0.39 to 0.70. A recording layer and the fourth recording layer are formed.

  According to the study of the present inventor, the optical functional layer comprises a first recording layer, a second recording layer, a third recording layer, and a fourth recording layer in this order from the substrate side, The second recording layer has a thickness of 20 nm to 50 nm, the ratio of the thickness of the third recording layer to the thickness of the second recording layer is 0.48 to 0.93, and the thickness of the fourth recording layer is The first recording layer, the second recording layer, the third recording layer, and the fourth recording layer are formed such that the ratio of the thickness to the thickness of the second recording layer is 0.39 to 0.70. If so, the amount of the laser beam absorbed by the second recording layer, the amount of the laser beam absorbed by the third recording layer, and the amount of the laser beam absorbed by the fourth recording layer And the laser beam absorptivity of the second recording layer, the third recording layer, and the fourth recording layer can be sufficient. It has been found that it can be set to a high level, ie 10% to 20%, and therefore according to a further preferred embodiment of the invention, the second recording layer, the third recording layer and the fourth recording layer. By irradiating the recording layer with a recording laser beam having the same power, data can be recorded as desired.

  Furthermore, according to the study of the present inventor, the optical functional layer comprises a first recording layer, a second recording layer, a third recording layer, and a fourth recording layer in this order from the substrate side. The second recording layer has a thickness of 20 nm to 50 nm, and the ratio of the thickness of the third recording layer to the thickness of the second recording layer is 0.48 to 0.93; The first recording layer, the second recording layer, the third recording layer, and the fourth recording layer such that the ratio of the layer thickness to the second recording layer thickness is 0.39 to 0.70. Is formed, the reflectance of the second recording layer for the laser beam, the reflectance of the third recording layer for the laser beam, and the reflectance of the fourth recording layer for the laser beam may be substantially equal. And it has been found that the respective reflectivities can be sufficiently high, and thus the present invention According to a preferred embodiment, the second recording layer, from any of the recording layers of the third recording layer and the fourth recording layer, the data, as desired, can be reproduced.

  In the present invention, more preferably, the ratio of the thickness of the third recording layer to the thickness of the second recording layer is 0.50 to 0.90, and the thickness of the fourth recording layer is The second recording layer, the third recording layer, and the fourth recording layer are formed such that a ratio with respect to the thickness of the second recording layer is 0.39 to 0.65. Preferably, the ratio of the thickness of the third recording layer to the thickness of the second recording layer is 0.57 to 0.80, and the thickness of the fourth recording layer and the second recording layer The second recording layer, the third recording layer, and the fourth recording layer are formed such that the ratio with the thickness of the layer is 0.42 to 0.54.

  In a further preferred embodiment of the present invention, the element X is constituted by at least one element selected from the group consisting of S, O, C and N.

  S, O, C and N are 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. , It can be preferably used as the element X. Above all, O and S, which are Group 6B elements, have appropriate reactivity, and have too high reactivity like F and Cl, which are Group 7B elements, so that they are irradiated with a laser beam for recording. At least, there is no problem of reacting with the metal element M, which is particularly preferable.

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

  In the present invention, when at least one recording layer containing the metal M and the element X further contains Mg, the content of Mg is preferably 18.5 atomic% to 33.7 atomic%. More preferably, it is 20.0 atomic% to 33.5 atomic%.

  On the other hand, in the present invention, when at least one recording layer containing the metal M and the element X further contains Al, the content of Al is preferably 11 to 40 atomic%, and is preferably 18 to 40 atomic%. % To 32 at%.

  In the present invention, when at least one recording layer containing the metal M and the element X further contains Ti, the content of Ti is preferably from 8 to 34 at%, preferably 10 to 34 at%. % To 26 at%.

  In a further preferred embodiment of the present invention, of the plurality of recording layers, a recording layer farthest from the light transmitting layer of the laser beam, 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, of the plurality of recording layers, a recording layer farthest from the laser beam light transmitting layer, a first recording film containing Cu as a component, and Si as a main component Since the second recording film includes a second recording film, the noise level of a reproduced signal when reproducing data recorded on the recording layer farthest from the light transmitting layer can be suppressed to a lower level. The difference in reflectivity before and after recording can be increased, and even when the optical recording disk is stored for a long period of time, the recorded data can be prevented from deteriorating. Can be increased.

  In another preferred embodiment of the present invention, the optically functional layer includes a plurality of recording layers stacked at least with an intermediate layer interposed, and a recording layer farthest from a light transmitting layer among the plurality of recording layers. At least one recording layer other than the layer includes 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. , S, O, C and N as at least one element selected from the group consisting of Mg, Al and Ti as additives.

  According to the study of the present inventor, at least one recording layer different from the recording layer farthest from the light transmitting layer is composed of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, and Pb. , Bi, Zn and La, at least one metal selected from the group consisting of S, O, C and N, and at least one element selected from the group consisting of N as a main component, and a group consisting of Mg, Al and Ti It has been found that, when at least one metal selected from the group consisting of additives is contained as an additive, the recording layer has a sufficient light transmittance to a laser beam.

  Therefore, according to another preferred embodiment of the present invention, data can be recorded on the recording layer farthest from the light transmitting layer as desired, and the recorded data can be reproduced, and Data can be recorded on the recording layers other than the farthest recording layer as desired, and the recorded data can be reproduced.

  In the present invention, among the plurality of recording layers, all the recording layers other than the recording layer farthest from the light transmitting layer are Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, It contains at least one metal selected from the group consisting of Pb, Bi, Zn and La, and at least one element selected from the group consisting of S, O, C and N as main components, and consists of Mg, Al and Ti. It is preferable to include at least one metal selected from the group as an additive.

  In a preferred embodiment of the present invention, 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; The recording layer containing, as a main component, at least one element selected from the group consisting of S, O, C, and N, and at least one metal selected from the group consisting of Mg, Al, and Ti as an additive. At least one metal selected from the group consisting of Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn and La; and a group consisting of S, O, C and N A target containing, as a main component, at least one selected element; and a target containing, as a main component, at least one metal selected from the group consisting of Mg, Al, and Ti. Using, by a vapor deposition method, it is formed.

In a further preferred embodiment of the present invention, 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 , S, O, C and N, the recording layer containing, as a main component, at least one element selected from the group consisting of Mg, Al, and Ti as an additive. target containing a target comprising a mixture or a mixture of _La 2 _O 3, SiO ₂ and _Si 3 _{N 4} and SiO ₂ as a main component, which Mg, at least one metal selected from the group consisting of Al and Ti as a main component And is formed by a vapor deposition method.

In a further preferred embodiment of the present invention, 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 , S, O, C and N, the recording layer containing, as a main component, at least one element selected from the group consisting of Mg, Al, and Ti as an additive. using and a target comprising a mixture or _La 2 _O 3, a mixture of SiO ₂ and _Si 3 _{N 4} and SiO _2, Mg, and a target consisting of at least one metal selected from the group consisting of Al and Ti, the gas It is formed by a phase growth method.

In the present invention, when a target containing a mixture of ZnS and SiO ₂ is used, the molar ratio between ZnS and SiO ₂ contained in the target is preferably set to 50:50 to 90:10. It is more preferable to set the ratio to 80:20.

When the molar ratio of ZnS in the mixture of ZnS and SiO ₂ is 40% or more, the reflectivity and the light transmittance with respect to the laser beam of the recording layer, both, can be improved, ZnS and a SiO ₂ When the molar ratio of ZnS in the mixture is 80% or less, it is possible to effectively prevent cracks from being generated in the recording layer due to stress. Further, when the molar ratio of ZnS to SiO ₂ in the mixture of ZnS and SiO ₂ is 65:35 to 75:25, the occurrence of cracks in the recording layer is more effectively prevented while preventing the recording layer from cracking. It is possible to further improve the reflectance and the light transmittance of the layer with respect to the laser beam.

Further, in the present invention, when a target containing a mixture of La ₂ O ₃ , SiO ₂ and Si ₃ N ₄ is used, the molar ratio of SiO ₂ contained in the target to La ₂ O ₃ and Si ₃ N ₄ Is preferably set to 10:90 to 50:50, and more preferably, the molar ratio to La ₂ O ₃ , SiO ₂ and Si ₃ N ₄ is set to 20:30:50.

When the molar ratio of SiO _{2 in} the mixture of La ₂ O ₃ , SiO ₂ and Si ₃ N ₄ is less than 10%, cracks easily occur in the recording layer, and the molar ratio of SiO ₂ exceeds 50%. At times, the reflectance of the recording layer decreases due to the decrease in the refractive index. On the other hand, when the molar ratio of Si ₃ N ₄ and La ₂ O ₃ is 50% to 90%, the refractive index of the recording layer can be increased, and the occurrence of cracks can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, the jitter at the time of data reading can be suppressed within a desired range, it becomes possible to suppress the occurrence of an error at the time of data reading, and hold the push-pull signal level at or above a desired value. It is possible to provide an optical recording disk capable of performing tracking control as desired.

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

  FIG. 1 is an enlarged sectional view of a substantial part of an optical recording disk according to a preferred embodiment of the present invention.

  As shown in FIG. 1, an optical recording disk 1 according to the present embodiment is configured as a write-once optical recording disk, and includes a support substrate 2, a reflective layer 3, a second dielectric layer 4, It comprises a second recording film 5, a first recording film 6, a first dielectric layer 8, and a light transmitting layer 9. In this embodiment, the recording layer 7 is formed by the first recording film 6 and the second recording film 5.

  The support substrate 2 functions as a support for ensuring the mechanical strength required for the optical recording disk 1.

  The material for forming the support substrate 2 is not particularly limited as long as it can function as a support for the optical recording disk 1. The support substrate 2 can be formed of, for example, glass, ceramics, resin, or the like. Among these, resins are preferably used from the viewpoint of ease of molding. Examples of such a resin include a polycarbonate resin, an acrylic resin, an epoxy resin, a polystyrene resin, a polyethylene resin, a polypropylene resin, a silicone resin, a fluorine resin, an ABS resin, and a urethane resin. Among these, a polycarbonate resin is particularly preferable in terms of workability, optical characteristics, and the like. In the present embodiment, the support substrate 2 is formed of a polycarbonate resin.

  In the present embodiment, the support substrate 2 has a thickness of about 1.1 mm.

  As shown in FIG. 1, on one main surface of the support substrate 2, grooves G having a substantially trapezoidal cross section and lands L having a substantially trapezoidal cross section are alternately formed.

  As is well known, the support substrate 2 includes a stamper (a stamper) in which a concave / convex pattern symmetrical to the concave / convex pattern of the groove G and the land L to be formed on one principal surface of the support substrate 2 is formed on one principal surface thereof. (Not shown) by an injection molding method.

  FIG. 2 is a schematic sectional view showing details of the sectional shapes of the groove G and the land L.

  As shown in FIG. 2, in the present embodiment, the groove G and the land L each have a substantially trapezoidal cross section, the depth Gd of the groove G is 15 nm or more and 25 nm or less, and the groove G is half of the groove G. The value width Gw is formed so as to be 150 nm or more and 230 nm or less.

  As shown in FIG. 2, in the present embodiment, the angle θ of the inclined surface between the adjacent groove G and the land L with respect to one main surface of the support substrate 2 is set to be 12 ° to 30 °. , A groove G and a land L are formed.

  The support substrate 2 is formed of, for example, polycarbonate. As shown in FIG. 1, a reflection layer 3 is formed on one main surface of the support substrate 2 on which the grooves G and the lands L are formed by a sputtering method or the like. ing.

  The reflection layer 3 has a function of reflecting the incident laser beam LB via the light transmission layer 9 and emitting the laser beam LB from the light transmission layer 9 again.

  Although the thickness of the reflective layer 3 is not particularly limited, it is preferably from 10 nm to 300 nm, and particularly preferably from 20 nm to 200 nm.

  The material for forming the reflective layer 3 is not particularly limited as long as it can reflect the laser beam LB, and is not particularly limited. Mg, Al, Ti, Cr, Fe, Co, Ni, Cu, Zn, Ge, Ag, Pt , Au, etc., the reflection layer 3 can be formed. Among them, a metal material such as Al, Au, Ag, Cu having high reflectivity, or an alloy containing at least one of these metals such as an alloy of Ag and Cu forms the reflective layer 3. It is preferably used for forming.

  When reproducing the data recorded on the recording layer 7 using the laser beam LB, the reflective layer 3 increases the difference in reflectance between the recorded portion and the unrecorded portion due to the multiple interference effect, thereby achieving high reproduction. It is provided to obtain a signal (C / N ratio).

  As shown in FIG. 1, a second dielectric layer 4 is formed on the surface of the reflective layer 3 by a sputtering method or the like, and a second dielectric layer 4 is formed on the surface of the second dielectric layer 4 by a sputtering method or the like. A second recording film 5 is formed.

  As shown in FIG. 1, a first recording film 6 is formed on the surface of the second recording film 5 by a sputtering method or the like, and the recording layer is formed by the first recording film 6 and the second recording film 5. 7 are formed.

  As shown in FIG. 1, a first dielectric layer 8 is formed on the surface of the first recording film 6 by a sputtering method or the like, and a light transmitting layer is formed on the surface of the first dielectric layer 8. 9 are formed.

  The first dielectric layer 8 and the second dielectric layer 4 serve to protect the recording layer 7. Therefore, the first dielectric layer 8 and the second dielectric layer 4 can effectively prevent deterioration of recorded data for a long period of time. Further, the second dielectric layer 4 has an effect of preventing thermal deformation of the support substrate 2 and the like, and therefore, it is possible to effectively prevent deterioration of jitter due to the deformation.

The dielectric material for forming the first dielectric layer 8 and the second dielectric layer 4 is not particularly limited as long as it is a transparent dielectric material. For example, oxide, sulfide, The first dielectric layer 8 and the second dielectric layer 4 can be formed of a dielectric material mainly containing nitride or a combination thereof. More specifically, in order to prevent thermal deformation of the substrate 2 and the like and protect the recording layer 7, the first dielectric layer 8 and the second dielectric layer 4 are made of Al ₂ O ₃ , AlN, ZnO. , ZnS, GeN, GeCrN, CeO, SiO, SiO ₂ , SiN and SiC, preferably containing at least one dielectric material as a main component, and containing ZnS · SiO ₂ as a main component. Is more preferable.

  The thicknesses of the first dielectric layer 8 and the second dielectric layer 4 are not particularly limited, but are preferably 3 to 200 nm. If the thickness of the first dielectric layer 8 or the second dielectric layer 4 is less than 3 nm, it is difficult to obtain the above-described effects. On the other hand, if the thickness of the first dielectric layer 8 or the second dielectric layer 4 exceeds 200 nm, the time required for film formation becomes longer, and the productivity of the optical recording disk 1 may be reduced. In addition, cracks may occur in the optical recording disk 1 due to the stress of the first dielectric layer 8 or the second dielectric layer 4.

  In the present embodiment, the light transmitting layer 9 is formed by applying a UV curable resin solution to the surface of the second dielectric layer 8 by a spin coating method to form a coating film, and irradiating the coating film with ultraviolet rays. As shown in FIG. 1, the main surface of the light transmitting layer 9 facing the support substrate 2 is provided with one main surface of the support substrate 2. The shapes of the formed grooves G and lands L are transferred, and the same concavo-convex pattern as the plurality of grooves G and lands L formed on one main surface of the support substrate 2 is formed.

  In the optical recording disk 1 according to the present embodiment, through an objective lens (not shown) having a numerical aperture (NA) of 0.8 to 0.9, in the direction indicated by the arrow in FIG. The recording layer 7 is irradiated with the laser beam LB having a wavelength of 430 nm and is irradiated with the laser beam LB through the light transmission layer 9 to record data. The recording layer 7 is transmitted through the light transmission layer 9 to the recording layer 7. The data is reproduced from the recording layer 7 by irradiation with the laser beam LB.

  In the present embodiment, the first recording film 6 contains Si as a main component, and the second recording film 5 contains Cu as a main component.

  When the recording layer 7 of the optical recording disk 1 is irradiated with the laser beam LB, Cu contained as a main component in the second recording film 5 is contained as a main component in the first recording film 6. It mixes quickly with Si to form a mixed region and a recording mark. In this way, the reflectivity of the region of the recording layer where the recording marks are formed by mixing Si and Cu is greatly different from the reflectivity of the blank region where the recording marks are not formed of the recording layer 7. Thus, data can be recorded quickly.

  In order to improve the recording sensitivity of the optical recording disk 1, the first recording film 6 is further selected from the group consisting of Mg, Al, Cu, Ag, and Au, and is included in the first recording film 6 as a main component. It is preferable that one or more elements different from the added elements are added.

  In order to improve the storage reliability and recording sensitivity of the optical recording disk 1, at least one element selected from the group consisting of Al, Zn, Sn and Au is further added to the second recording film 5. Is preferred.

  When at least one element selected from the group consisting of Al, Zn, Sn and Au is added to the second recording film 5, the stability of the second recording film 5 against oxidation or sulfidation is greatly reduced. The appearance of the optical recording disk 1 such as peeling of the second recording film 5 due to the corrosion of Cu contained as a main component in the second recording film 5 and light after long-term storage. A change in the reflectance of the recording disk 1 can be effectively prevented.

  It is particularly preferable that Au is further added to the second recording film 5 in order to improve the recording sensitivity of the optical recording disk 1.

  The thickness of the recording layer 7, that is, the total thickness of the first recording film 6 and the second recording film 5, is a region irradiated with the laser beam LB, and is included as a main component in the first recording film 6. Si and Cu contained as a main component in the second recording film 5 quickly melt or diffuse, and Si contained as a main component in the first recording film 6 and the second recording film 5 It is sufficient that a region in which Cu contained as a main component in the film 5 is mixed is quickly formed and a recording mark is formed, and the recording mark is not particularly limited. The total thickness of the recording film 5 is preferably from 2 nm to 100 nm, more preferably from 2 nm to 50 nm.

  When the total thickness of the first recording film 6 and the second recording film 5 exceeds 100 nm, Si contained as a main component in the first recording film 6 and the second recording film 5 mainly contain Si. The mixing speed with Cu contained as a component becomes low, and it becomes difficult to record data at high speed.

  On the other hand, when the thickness of the first recording film 6 and the total thickness of the second recording film 5 are less than 2 nm, the change in reflectance before and after the irradiation of the laser beam LB is small, and high intensity reproduction is performed. A signal (C / N ratio) cannot be obtained.

  Although the thickness of each of the first recording film 6 and the second recording film 5 is not particularly limited, the recording sensitivity is sufficiently improved, and the change in reflectance before and after recording data is sufficiently reduced. In order to increase the thickness, it is preferable that the thickness of the first recording film 6 is 1 nm to 30 nm, and the thickness of the second recording film 5 is 1 nm to 30 nm.

  Furthermore, in order to sufficiently increase the change in reflectance before and after the irradiation of the laser beam LB, the ratio of the thickness of the first recording film 6 to the thickness of the second recording film 5 (the first recording film 6 (Thickness / thickness of second recording film 5) is preferably 0.2 to 5.0.

  Although not shown in FIGS. 1 and 2, in the present embodiment, the groove G and the land L are formed such that the wobble amount Wob is ± 7 nm to ± 25 nm.

  According to the study of the present inventor, as described above, the optical recording disk 1 having the groove G and the land L formed on one main surface of the support substrate 2 and the main surface of the light transmission layer 9 facing the support substrate 2. In the above, the jitter at the time of data reading can be suppressed within a desired range, the occurrence of an error at the time of data reading can be suppressed, and the push-pull signal level can be maintained at a desired value or more. It has been found that tracking control can be performed as desired.

  FIG. 3 is a schematic sectional view of an optical recording disk according to another preferred embodiment of the present invention.

  As shown in FIG. 3, the optical recording disk 10 according to the present embodiment is configured as a write-once optical recording disk, and includes a support substrate 11, a transparent intermediate layer 12, a light transmission layer 13, and a support substrate 11. And an L1 layer 20 provided between the transparent intermediate layer 12 and the light transmitting layer 13.

  The L0 layer 20 and the L1 layer 30 are recording layers for recording data, and the optical recording disk 10 according to the present embodiment has two recording layers.

  The L0 layer 20 forms a recording layer far from the light incident surface 13a, and a reflective film 21, a fourth dielectric film 22, an L0 recording layer 23, and a third dielectric film 24 are laminated from the support substrate 11 side. And is configured.

  On the other hand, the L1 layer 30 constitutes a recording layer close to the light incident surface 13a, and the reflection film 31, the second dielectric film 32, the L1 recording layer 33, and the first dielectric film 34 are arranged from the support substrate 11 side. Stacked and configured.

  When data is recorded on the L0 layer 20 and data recorded on the L0 layer 20 is reproduced, the laser beam LB is irradiated via the L1 layer 30 located on the side closer to the light incident surface 13a.

  Therefore, the L1 layer 30 needs to have high light transmittance. Specifically, it is necessary that the L1 layer 30 has a light transmittance of 30% or more with respect to the wavelength of the laser beam LB used for recording and reproducing data, and a light transmittance of 40% or more. It is preferable to have

  Similarly to the optical recording disk 1 shown in FIGS. 1 and 2, the support substrate 11 is made of, for example, polycarbonate.

  As shown in FIG. 3, a groove G having a substantially trapezoidal cross section and a land L having a substantially trapezoidal cross section are alternately formed on one main surface of the support substrate 11, and FIG. 1 and FIG. Similarly to the optical recording disk 1 shown, also in this embodiment, the groove G and the land L have a depth Gd of the groove G of 15 nm or more and 25 nm or less, and a half value width Gw of the groove G of 150 nm or more. The angle θ of the inclined surface between the adjacent groove G and the land L with respect to one main surface of the support substrate 11 is 12 ° to 30 °.

  Although not shown in FIG. 3, also in this embodiment, the groove G and the land L are formed such that the wobble amount Wob is ± 7 nm to ± 25 nm.

  The transparent intermediate layer 12 has a function of physically and optically separating the L0 layer 20 and the L1 layer 30 from each other with a sufficient distance.

  As shown in FIG. 3, on the main surface of the transparent intermediate layer 12 facing the light transmitting layer 13, the same concavo-convex pattern as the plurality of grooves G and the lands L formed on one main surface of the support substrate 11 is provided. Is formed.

  The transparent intermediate layer 12 is formed by applying a UV curable resin solution onto the L0 layer 20 by a spin coating method to form a coating film, and a stamper used to form the support substrate 11 on the surface of the coating film. In a state where a stamper (not shown) having the same concavo-convex pattern as that of the transparent intermediate layer 12 (not shown) is covered, the stamper is formed by irradiating ultraviolet rays through the stamper. On the main surface facing the transmission layer 13, a concavo-convex pattern similar to the plurality of grooves G and lands L formed on one main surface of the support substrate 11 is formed.

  The transparent intermediate layer 12 is preferably formed to have a thickness of 5 μm to 50 μm, and more preferably, to have a thickness of 10 μm to 40 μm.

  The transparent intermediate layer 12 needs to have sufficiently high light transmittance because the laser beam LB passes when data is recorded on the L0 layer 20 and data is reproduced from the L0 layer 20.

  The light transmitting layer 13 is a layer that transmits the laser beam LB, and one surface of the light transmitting layer 13 forms a light incident surface 13a.

  As shown in FIG. 3, on the main surface of the light transmission layer 13 facing the transparent intermediate layer 12, a concave and convex pattern of the groove G and the land L formed on the main surface of the transparent intermediate layer 12 on the L1 layer 30 side, That is, an uneven pattern similar to the uneven pattern of the groove G and the land L formed on the main surface of the support substrate 11 on the L0 layer 20 side is formed.

  The light transmitting layer 13 is formed by applying a UV curable resin solution onto the L1 layer 30 by a spin coating method to form a coating film, and irradiating the surface of the coating film with UV light to cure the coating film. As a result, the concave / convex pattern of the groove G and the land L formed on one main surface of the transparent intermediate layer 12 on the L1 layer 30 side, that is, on the one main surface of the support substrate 11 on the L0 layer 20 side. The formed concavo-convex pattern of the groove G and the land L is transferred to the main surface of the light transmitting layer 13 facing the transparent intermediate layer 12, and the supporting substrate is formed on the main surface of the light transmitting layer 13 facing the transparent intermediate layer 12. An uneven pattern similar to the groove G and the land L formed on the main surface of the L0 layer 20 side of No. 11 is formed.

  The light transmitting layer 13 is preferably formed to have a thickness of 30 μm to 200 μm.

  The light transmitting layer 13 needs to have sufficiently high light transmittance because the laser beam LB passes when data is recorded on the L1 layer 30 and data is reproduced from the L1 layer 30. .

  As shown in FIG. 3, the L0 recording layer 23 included in the L0 layer 20 includes a first L0 recording film 23a and a second L0 recording film 23b in contact with the first L0 recording film 23a. .

  The first L0 recording film 23a and the second L0 recording film 23b are the first recording film 6 and the second recording film 5 constituting the recording layer 7 of the optical recording disk 1 shown in FIGS. The first L0 recording film 23a contains Si as a main component, and the second L0 recording film 23b contains Cu as a main component.

  Therefore, when the L0 recording layer 23 is irradiated with the laser beam LB, Si contained as a main component in the first L0 recording film 23a and Cu contained as a main component in the second L0 recording film 23b are obtained. Are mixed quickly to form a mixed area, a recording mark is formed on the L0 recording layer 23, and data is recorded.

  Similarly, as shown in FIG. 3, the L1 recording layer 33 included in the L1 layer 30 includes a first L1 recording film 33a and a second L1 recording film 33b in contact with the first L1 recording film 33a. Have.

  The first L1 recording film 33a and the second L1 recording film 33b are composed of the first recording film 6 and the second recording film 5 constituting the recording layer 7 of the optical recording disk 1 shown in FIGS. The first L1 recording film 33a contains Si as a main component, and the second L0 recording film 33b contains Cu as a main component.

  Accordingly, when the L1 recording layer 33 is irradiated with the laser beam LB, Si contained as the main component in the first L1 recording film 33a and Cu contained as the main component in the second L1 recording film 33b are used. Are quickly mixed to form a mixed area, a recording mark is formed on the L1 recording layer 33, and data is recorded.

  The L1 recording layer 33 records data on the L0 recording layer 23 included in the L0 layer 20 and, when reproducing data from the L0 recording layer 23 of the L0 layer 20, transmits the laser beam LB. If the difference between the light transmittance of the area where the recording mark is formed and the light transmittance of the blank area of the L1 recording layer 33 where no recording mark is formed is large, the data is stored in the L0 recording layer 23 included in the L0 layer 20. When recording the laser beam LB, the laser beam LB applied to the L0 recording layer 23 depends on whether the area of the L1 recording layer 33 through which the laser beam LB is transmitted is the area where the recording mark is formed or the blank area. The laser beam L reflected by the L0 recording layer 23, transmitted through the L1 layer 30, and detected when the data is reproduced from the L0 recording layer 23 of the L0 layer 20 while the light amount greatly changes. Greatly changes, and as a result, depending on whether the area of the L1 recording layer 33 through which the laser beam LB passes is the area where the recording mark is formed or the blank area, the recording characteristics for the L0 recording layer 23 and L0 There is a problem that the amplitude of a signal reproduced from the recording layer 23 changes greatly.

  In particular, when reproducing data recorded on the L0 recording layer 23, the region of the L1 recording layer 33 through which the laser beam LB passes includes a boundary between a region where a recording mark is formed and a blank region. In this case, since the reflectance distribution in the spot of the laser beam LB is not constant, it is impossible to reproduce the data recorded in the L0 recording layer 23 as desired.

  According to the research of the present inventor, in order to record data on the L0 recording layer 23 and reproduce data from the L0 recording layer 23 as desired, the area where the recording mark of the L1 recording layer 33 is formed. It has been found that it is preferable that the difference between the light transmittance of the blank region and the light transmittance of the blank region should be 4% or less.

  Further, according to the study of the present inventor, the light transmittance of the region of the formed recording mark with respect to the laser beam LB having a wavelength of 400 nm to 430 nm, which is obtained by mixing Si and Cu, and the ratio of Si containing Cu as a main component. The difference between the light transmittance of the blank region of the L1 recording layer 33, in which one L1 recording film 33a and the second L1 recording film 33b containing Cu as a main component are laminated, with respect to the laser beam LB having a wavelength of 400 to 430 nm is For the laser beam LB having a wavelength of about 405 nm, which is not more than 4%, the light transmittance of the area of the L1 recording layer 33 where the recording mark is formed and the light transmittance of the blank area of the L1 recording layer 33 are shown. The difference has been found to be less than 1%.

  Therefore, in the present embodiment, the first L1 recording film 33a of the L1 recording layer 33 contains Si as a main component, the second L1 recording film 33b of the L1 recording layer 33 contains Cu as a main component, and the light transmission When the laser beam LB is irradiated through the layer 13, Si included as a main component in the first L1 recording film 33a and Cu included as a main component in the second L1 recording film 33b are mixed. Since the laser beam LB is applied to the L0 recording layer 23 through the L1 layer 30 so that the recording mark is formed, the data is recorded on the L0 recording layer 23 as desired. And the data recorded on the L0 recording layer 23 can be reproduced.

  The L1 recording layer 33 has a high light transmittance because the laser beam LB is transmitted when data is recorded on the L0 recording layer 23 included in the L0 layer 20 and data is reproduced from the L0 recording layer 23 of the L0 layer 20. Therefore, it is preferable that the L1 recording layer 33 be formed so that its film thickness is smaller than the film thickness of the L0 recording layer 23.

  Specifically, the L0 recording layer 23 is preferably formed to have a thickness of 2 nm to 40 nm, and the L1 recording layer 33 is preferably formed to have a thickness of 2 nm to 15 nm. preferable.

  When the thicknesses of the L1 recording layer 33 and the L0 recording layer 23 are less than 2 nm, the change in reflectance before and after the irradiation of the laser beam LB is small, and a high-intensity reproduction signal (C / N ratio) is obtained. You will not be able to do it.

  On the other hand, if the thickness of the L1 recording layer 33 exceeds 15 nm, the light transmittance of the L1 layer 30 decreases, and the characteristics of recording data on the L0 recording layer 23 and the characteristics of reproducing data from the L0 recording layer 23 deteriorate. Would.

  On the other hand, if the thickness of the L0 recording layer 23 exceeds 40 nm, the recording sensitivity deteriorates.

  Further, in order to sufficiently increase the change in the reflectance before and after the irradiation with the laser beam LB, the thickness of the first L1 recording film 33a included in the L1 recording layer 33 and the thickness of the second L1 recording film 33b are changed. The ratio (the thickness of the first L1 recording film 33a / the thickness of the second L1 recording film 33b) and the thickness of the first L0 recording film 23a included in the L0 recording layer 23 and the second L0 recording film 23b The ratio to the thickness (the thickness of the first L0 recording film 23a / the thickness of the second L0 recording film 23b) is preferably 0.2 to 5.0.

  The third dielectric film 24 and the second dielectric film 22 function as protective films for protecting the L0 recording layer 23, and the first dielectric film 34 and the second dielectric film 32 It functions as a protective film that protects 33.

  The thicknesses of the first dielectric film 34, the second dielectric film 32, the third dielectric film 24, and the fourth dielectric film 22 are not particularly limited, but may be 10 nm to 200 nm. Preferably. When the thickness of these dielectric films is less than 10 nm, the function as a protective film is not sufficient. On the other hand, when the thickness of these dielectric films exceeds 200 nm, it is necessary for film formation. The time may be prolonged, the productivity may be reduced, and cracks may occur in the L0 recording layer 23 and the L1 recording layer 33 due to internal stress.

The material for forming the first dielectric film 24, the second dielectric film 22, the third dielectric film 34, and the fourth dielectric film 32 is not particularly limited, but Al ₂ O ₃ , AlN, SiO ₂ , Si ₃ N ₄ , CeO ₂ , ZnS, TaO, and the like, and oxides, nitrides, sulfides, carbides, and mixtures thereof such as Al, Si, Ce, Zn, Ta, and Ti are used. Te, the first dielectric film 24, the second dielectric film 22, to form the third dielectric film 34 and the fourth dielectric film 32 preferably, in particular, a dielectric made of ZnS · SiO ₂ It is more preferable to use as a main component. Here, “ZnS · SiO ₂ ” means a mixture of ZnS and SiO ₂ .

  The reflection film 31 included in the L1 layer 30 reflects the laser beam LB incident from the light incident surface 13a and emits the laser beam LB again from the light incident surface 13a. It plays the role of effectively dissipating the heat generated in 33.

  When data is recorded on the L0 recording layer 23 of the L0 layer 20 and data recorded on the L1 recording layer 23 of the L0 layer 20 is reproduced, the laser beam LB incident from the light incident surface 13a is applied to the L1 layer 30. The light is irradiated to the L1 recording layer 23 of the L0 layer 20 through the reflection film 31 included in the L0 layer 20. Therefore, it is necessary to use a material having high light transmittance and high thermal conductivity as the material of the reflection film 31. is there. Further, the material of the reflection film 31 is also required to have high long-term storage reliability.

  Therefore, in the present embodiment, the reflection film 31 included in the L1 layer 30 contains Ag as a main component, and contains 0.5 to 5.0 atomic% of C as an additive.

  The thickness of the reflective film 31 included in the L1 layer 30 may be determined in consideration of the added amount of C since the light transmittance and the thermal conductivity change depending on the added amount of C. Is preferably less than 5 nm, more preferably 5 nm to 15 nm.

  The reflection film 21 included in the L0 layer 20 reflects the laser beam LB incident from the light incident surface 13a and emits the laser beam LB again from the light incident surface 13a. 20 plays a role of effectively dissipating the heat generated.

  The reflection film 21 included in the L0 layer 20 is preferably formed to have a thickness of 20 nm to 200 nm. If the thickness of the reflection film 21 included in the L0 layer 20 is less than 20 nm, it becomes difficult to radiate the heat generated in the L0 recording layer 23, while the thickness of the reflection film 21 is reduced to 200 nm. If it exceeds, it takes a long time to form the reflective film 21, which lowers productivity and may cause cracks due to internal stress or the like.

  The material for forming the reflection film 21 included in the L0 layer 20 is not particularly limited. The reflective film 21 can be formed using the same material as the reflective film 31. However, unlike the reflective film 31 included in the L1 layer 30, when selecting the material of the reflective film 21 included in the L0 layer 20, There is no need to consider light transmittance.

  According to the study of the present inventors, as described above, the optical recording disk in which the groove G and the land L are formed on one main surface of the support substrate 11 and the main surface of the transparent intermediate layer 12 facing the light transmitting layer 13. In No. 10, the jitter at the time of data reading can be suppressed within a desired range, the occurrence of an error at the time of data reading can be suppressed, and the push-pull signal level can be maintained at or above a desired value. And it has been found that tracking control can be performed as desired.

  FIG. 4 is a schematic sectional view of an optical recording disk according to another preferred embodiment of the present invention.

  The optical recording disk 40 according to the present embodiment is configured as a write-once optical recording disk, and as shown in FIG. 4, a support substrate 41, a first recording layer 50, and a first transparent intermediate layer 42. , A second recording layer 60, a second transparent intermediate layer 43, a third recording layer 70, and a light transmitting layer 45.

  The first recording layer 50, the second recording layer 60, and the third recording layer 70 are recording layers for recording data, respectively. The optical recording disc 40 according to the present embodiment has three recording layers. Have.

  As shown in FIG. 4, the optical recording disk 40 according to the present embodiment is configured such that the laser beam LB is irradiated on the light transmitting layer 45, and the light incident surface 45a is formed by one surface of the light transmitting layer 45. Is configured.

  As shown in FIG. 4, the first recording layer 50 constitutes a recording layer furthest from the light incident surface 45a, and the third recording layer 70 constitutes a recording layer closest to the light incident surface 45a. I have.

  Data was recorded on the first recording layer 50, the second recording layer 60, or the third recording layer 70, and was recorded on the first recording layer 50, the second recording layer 60, or the third recording layer 70. When reproducing data, a blue laser beam LB having a wavelength of 400 to 430 nm is emitted from the light incident surface 45a side, and the focal points thereof are the first recording layer 50, the second recording layer 60 and the third recording layer 60. To one of the recording layers 70.

  Therefore, when data is recorded on the first recording layer 50 and data recorded on the first recording layer 50 is reproduced, the first recording layer 60 and the third recording layer 70 pass through the first recording layer 70. When the recording layer 50 is irradiated with the laser beam LB, data is recorded on the second recording layer 60, and when the data recorded on the second recording layer 60 is reproduced, via the third recording layer 70, The second recording layer 60 is irradiated with the laser beam LB.

  Similarly to the optical recording disk 1 shown in FIGS. 1 and 2, the support substrate 41 is formed of, for example, polycarbonate.

  As shown in FIG. 4, a groove G having a substantially trapezoidal cross section and a land L having a substantially trapezoidal cross section are alternately formed on one main surface of the support substrate 41. Similarly to the optical recording disk 1 shown, also in this embodiment, the groove G and the land L have a depth Gd of the groove G of 15 nm or more and 25 nm or less, and a half value width Gw of the groove G of 150 nm or more. The angle θ of the inclined surface between the adjacent groove G and the land L with respect to one main surface of the support substrate 2 is 12 ° to 30 °.

  Although not shown in FIG. 4, also in the present embodiment, the groove G and the land L are formed such that the wobble amount Wob is ± 7 nm to ± 25 nm.

  As shown in FIG. 4, a first recording layer 50 is formed on the surface of the support substrate 41.

  FIG. 5 is a schematic enlarged sectional view of the first recording layer 50.

  As shown in FIG. 5, the first recording layer 50 includes a reflective film 51, a second dielectric film 52, a second recording film 53b, a first recording film 53a, and a first recording film 53 formed on a support substrate 41. Of dielectric films 54 are laminated.

  As shown in FIG. 5, a reflective film 51 is formed on the surface of the support substrate 41 by a vapor deposition method such as a sputtering method.

  The reflective film 51 reflects the laser beam LB incident from the light incident surface 45a and emits the laser beam LB again from the light incident surface 45a, and irradiates the second recording film 53b and the first recording film 53b by the irradiation of the laser beam LB. Plays a role in effectively dissipating the heat generated in the recording film 53a.

  The material for forming the reflective film 51 is not particularly limited as long as it can reflect the laser beam LB, and is not particularly limited. However, Mg, Al, Ti, Cr, Fe, Co, Ni, Cu, Zn, Ge, Ag, It can be formed of Pt, Au, or the like. Among them, Al, Au, Ag, Cu or an alloy thereof has a high reflectance and a high thermal conductivity, and is therefore preferably used for forming the reflective film 51.

  The reflection film 51 is preferably formed to have a thickness of 20 nm to 200 nm. When the thickness of the reflective film 51 is less than 20 nm, it is difficult to sufficiently increase the reflectance of the reflective film 51, and it is difficult to radiate the heat generated in the first recording layer 50. On the other hand, if the thickness of the reflective film 51 exceeds 200 nm, it takes a long time to form the reflective film 51, which lowers productivity and may cause cracks due to internal stress and the like. .

  As shown in FIG. 5, a second dielectric film 52 is formed on the surface of the reflective film 51 by a vapor deposition method such as a sputtering method.

  The second dielectric film 52 has a function of preventing thermal deformation of the support substrate 41, and further protects the first recording film 53a and the second recording film 53b together with the first dielectric film 54. Functions as a protective film.

The material for forming the second dielectric film 52 is not particularly limited as long as it is a transparent dielectric material in the wavelength region of the laser beam LB, and examples thereof include oxides, nitrides, and sulfides. , Fluoride, or a dielectric material mainly containing a combination thereof can form the second dielectric film 52. The second dielectric film 52 is preferably made of Si, Ge, Zn , Al, Ta, Ti, Co, Zr, Pb, Ag, Sn, Ca, Ce, V, Cu, Fe and Mg containing at least one metal selected from the group consisting of oxides, nitrides, sulfides, and fluorides. Or a compound of these. As a dielectric material for forming the second dielectric film 52, a mixture of ZnS and SiO ₂ is particularly preferable, and a molar ratio of ZnS to SiO ₂ is 50:50 to 85:15. And more preferably about 80:20.

  As shown in FIG. 5, a second recording film 53b is formed on the surface of the second dielectric film 52 by a vapor deposition method such as a sputtering method, and further, a sputtering The first recording film 53a is formed by a vapor growth method such as a method.

  The first recording film 53a and the second recording film 53b are recording films for recording data.

  In this embodiment, the second recording film 53b contains Cu as a main component, and the first recording film 53a 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 second recording film 53b containing Cu as a main component. When these elements are added to the second recording film 53b containing Cu as a main component, it is possible to reduce the noise level of the reproduced signal and improve the reliability for long-term storage. Becomes possible.

  The first recording film 53a and the second recording film 53b are preferably formed so that the total thickness is 2 nm to 40 nm.

  When the total thickness of the first recording film 53a and the second recording film 53b is less than 2 nm, the change in reflectance before and after the irradiation of the laser beam LB is small, and a reproduced signal having a high C / N ratio can be reproduced. On the other hand, if the total thickness of the first recording film 53a and the second recording film 53b exceeds 40 nm, the recording sensitivity deteriorates.

  Although the thickness of each of the first recording film 53a and the second recording film 53b is not particularly limited, the ratio of the thickness of the first recording film 53a to the thickness of the second recording film 53b is not particularly limited. That is, it is preferable that the thickness of the first recording film 53a / the thickness of the second recording film 53b is 0.2 to 5.0.

  As shown in FIG. 5, a first dielectric film 54 is formed on the surface of the first recording film 53a by a vapor deposition method such as a sputtering method.

  The first dielectric film 54 can be formed of the same material as the second dielectric film 52.

  As shown in FIG. 4, on the surface of the first recording layer 50, a first transparent intermediate layer 42 is formed.

  The first transparent intermediate layer 42 has a function of physically and optically separating the first recording layer 50 and the second recording layer 60 from each other with a sufficient distance.

  As shown in FIG. 4, the main surface of the first transparent intermediate layer 42 facing the light transmitting layer 45 has the same structure as the plurality of grooves G and lands L formed on one main surface of the support substrate 41. An uneven pattern is formed.

  The first transparent intermediate layer 42 is formed by applying a UV curable resin solution onto the first recording layer 50 by a spin coating method to form a coating film, and forming the support substrate 41 on the surface of the coating film. It is formed by irradiating ultraviolet rays through the stamper with a stamper (not shown) in which the same concavo-convex pattern as the stamper (not shown) used for forming is formed. On the main surface of the first transparent intermediate layer 42 facing the light transmitting layer 45, the same concavo-convex pattern as the plurality of grooves G and lands L formed on one main surface of the support substrate 41 is formed.

  As shown in FIG. 4, a second recording layer 60 is formed on the surface of the first transparent intermediate layer 42 by a vapor deposition method such as a sputtering method. , A second transparent intermediate layer 43 is formed.

  The second transparent intermediate layer 43 has a function of physically and optically separating the second recording layer 60 and the third recording layer 70 from each other with a sufficient distance.

  As shown in FIG. 4, a plurality of grooves G and lands L formed on one main surface of the support substrate 41 are formed on the main surface of the second transparent intermediate layer 43 facing the second recording layer 60. A similar concavo-convex pattern is formed.

  The second transparent intermediate layer 43 is formed by applying a UV curable resin solution on the second recording layer 60 by a spin coating method to form a coating film, and forming the support substrate 41 on the surface of the coating film. It is formed by irradiating ultraviolet rays through the stamper with a stamper (not shown) in which the same concavo-convex pattern as the stamper (not shown) used for forming is formed. On the main surface of the second transparent intermediate layer 43 facing the second recording layer 60, the same concavo-convex pattern as the plurality of grooves G and lands L formed on one main surface of the support substrate 41 is formed.

  The first transparent intermediate layer 42 has a high light transmittance because the laser beam LB passes when data is recorded on the first recording layer 50 and data recorded on the first recording layer 50 is reproduced. It is necessary that the second transparent intermediate layer 43 records data on the first recording layer 50 and reproduces data recorded on the first recording layer 50. When recording data on the second recording layer 60 and reproducing data recorded on the second recording layer 60, the laser beam LB passes therethrough. is necessary.

  Each of the first transparent intermediate layer 42 and the second transparent intermediate layer 43 is preferably formed to have a thickness of 5 μm to 50 μm, and more preferably to have a thickness of 10 μm to 40 μm. ,It is formed.

  The second recording layer 60 is a recording layer for recording data, and in the present embodiment, is constituted by a single recording film.

  As shown in FIG. 4, a third recording layer 70 is formed on the surface of the second transparent intermediate layer 43 by a vapor deposition method such as a sputtering method.

  The third recording layer 70 is a recording layer for recording data, and in the present embodiment, is constituted by a single recording film.

  In the present embodiment, the second recording layer 60 and the third recording layer 70 contain Zn, Si, S, and O as main components, and include at least one metal selected from the group consisting of Mg, Al, and Ti. It is added as an additive.

Specifically, the second recording layer 60 is formed by a sputtering method using a target composed of a mixture of ZnS and SiO ₂ and a target composed of at least one metal selected from the group consisting of Mg, Al, and Ti. The first transparent intermediate layer 42 is formed on the surface of the first transparent intermediate layer 42 by a vapor deposition method such as the above. In this process, at least one metal selected from the group consisting of Mg, Al, and Ti acts as a reducing agent on the mixture of ZnS and SiO ₂ , so that Zn is separated from S, In the two recording layers 60, they are evenly dispersed in a simple form.

  On the other hand, although not necessarily clear, at least one metal selected from the group consisting of Mg, Al, and Ti used as a reducing agent binds to S separated from Zn or a part of S in ZnS, It is believed to form a compound.

The molar ratio of the mixture of ZnS and SiO ₂ contained in the target used when forming the second recording layer 60 is preferably set to 50:50 to 90:10, and is set to about 80:20. Is more preferable.

When the molar ratio of ZnS in the mixture of ZnS and SiO ₂ is 50% or more, both the reflectance and the light transmittance of the second recording layer 60 with respect to the laser beam LB can be improved, When the molar ratio of ZnS in the mixture of ZnS and SiO ₂ is 90% or less, generation of cracks in the second recording layer 60 due to stress can be effectively prevented.

Further, when the molar ratio of ZnS to SiO ₂ in the mixture of ZnS and SiO ₂ is set to 65:35 to 75:25, the occurrence of cracks in the second recording layer 60 can be more effectively prevented. In addition, the reflectance and the light transmittance of the second recording layer 60 with respect to the laser beam LB can be further improved.

  In this embodiment, when the second recording layer 60 contains Mg, the content of Mg is preferably 18.5 atomic% to 33.7 atomic%, and more preferably 20 atomic% to 33.5 atomic%. More preferably, it is atomic%.

  On the other hand, when the second recording layer 60 contains Al, the content of Al is preferably from 11 to 40 at%, more preferably from 18 to 32 at%. .

  When the second recording layer 60 contains Ti, the content of Ti is preferably from 8 to 34 at%, more preferably from 10 to 26 at%. .

In this embodiment, the second recording layer 60 and the third recording layer 70 have the same composition, and therefore, a target composed of a mixture of ZnS and SiO ₂ and a target composed of Mg, Al, and Ti A third recording layer 70 is formed on the surface of the second transparent intermediate layer 43 by a vapor deposition method such as a sputtering method using a target made of at least one metal selected from the group consisting of:

  In the present embodiment, the second recording layer 60 is formed to have a thickness of 15 nm to 50 nm, and the third recording layer 70 has a thickness D3 of the third recording layer 70. , And the ratio D3 / D2 to the thickness D2 of the second recording layer 60 is 0.40 to 0.70.

  The second recording layer 60 is a layer through which the laser beam LB passes when data is recorded on the first recording layer 50 and data recorded on the first recording layer 50 is reproduced. When the data recorded in the recording layer 50 is reproduced, it is necessary to have a sufficient light transmittance so that a high-level reproduced signal can be obtained. The third recording layer 70 records data on the first recording layer 50 and reproduces data recorded on the first recording layer 50, or records data on the second recording layer 60. When the data recorded on the second recording layer 60 is reproduced, since the laser beam LB is transmitted therethrough, the data recorded on the first recording layer 50 is reproduced, or When the data recorded in the recording layer 60 is reproduced, it is necessary to have a sufficient light transmittance so that a high-level reproduced signal can be obtained.

  On the other hand, when reproducing the data recorded on the second recording layer 60, the intensity of the laser beam LB reflected by the second recording layer 60 and emitted from the light incident surface 45a is detected, and the third recording is performed. When reproducing the data recorded in the layer 70, the intensity of the laser beam LB reflected by the third recording layer 70 and emitted from the light incident surface 45a is detected. The recording layer 70 has a sufficient reflectance to obtain a high-level reproduction signal when reproducing data recorded on the second recording layer 60 and the third recording layer 70. It is necessary.

In the present embodiment, each of the second recording layer 60 and the third recording layer 70 contains Zn, Si, S and O as main components, and at least one kind selected from the group consisting of Mg, Al and Ti. According to the study of the present inventors, the second recording layer 60 and the third recording layer 70 contain Zn, Si, S and O as main components, and contain Mg, Al and It has been found that when at least one metal selected from the group consisting of Ti is included as an additive, the light transmittance for a laser beam LB having a wavelength of 400 nm to 430 nm is high.
In the present embodiment, the second recording layer 60 and the third recording layer 70 have a ratio D3 / D3 of the thickness D3 of the third recording layer 70 to the thickness D2 of the second recording layer 60. D2 is formed to be 0.40 to 0.70, and according to the study of the present inventors, the thickness D2 of the second recording layer 60 is changed to the thickness D3 of the third recording layer 70. When the second recording layer 60 and the third recording layer 70 are formed so as to be larger than each other, both the second recording layer 60 and the third recording layer 70 have a wavelength of 400 nm to 430 nm. It has been found that the laser beam LB having λ has an even higher light transmittance.

  Therefore, according to the present embodiment, when data is recorded on the first recording layer 50, the power of the laser beam LB is reduced before the laser beam LB reaches the first recording layer 50. When the data recorded on the first recording layer 50 is reproduced, the data can be recorded on the first recording layer 50 as desired because it can be minimized. Since it is possible to minimize a decrease in the power of the laser beam LB reflected by the first recording layer 50, the data recorded on the first recording layer 50 And so on.

  According to the study of the present inventors, the second recording layer 60 and the third recording layer 70 contain Zn, Si, S and O as main components and are selected from the group consisting of Mg, Al and Ti. The second recording layer 60 and the third recording layer 70 include at least one metal as an additive, and the thickness D2 of the second recording layer 60 is larger than the thickness D3 of the third recording layer 70. It has been found that, when the recording layer is formed so that the recording layer is farther from the light incident surface 45a, the reflectivity with respect to the laser beam LB can be increased. Data can be reproduced not only from one recording layer 50 but also from the second recording layer 60 and the third recording layer 70 as desired.

  Further, the second recording layer 60 and the third recording layer 70 are irradiated with a recording laser beam LB having the same power, and the second recording layer 60 and the third recording layer 70 are similarly recorded so that data can be recorded. Preferably, the amount of the laser beam LB absorbed by the third recording layer 70 is substantially equal to the amount of the laser beam LB absorbed by the third recording layer 70.

  In order to reproduce the data recorded on the second recording layer 60 and the data recorded on the third recording layer 70 in the same manner, the laser beam LB is focused on the second recording layer 60. Then, when the laser beam LB is irradiated to the second recording layer 60 via the third recording layer 70, the reflectance of the second recording layer 60 with respect to the laser beam LB and the laser beam LB are subjected to the third recording. It is preferable that the reflectance of the third recording layer 70 with respect to the laser beam LB when the laser beam LB is irradiated on the third recording layer 70 by focusing on the layer 70 is substantially equal.

  According to the study of the present inventor, the second recording layer 60 has a thickness of 15 nm to 50 nm, and the thickness D3 of the third recording layer 70 and the thickness D2 of the second recording layer 60 are different from each other. When the second recording layer 60 and the third recording layer 70 are formed such that the ratio D3 / D2 becomes 0.40 to 0.70, the laser beam LB of the second recording layer 60 The amount of the absorbed laser beam LB and the amount of the laser beam LB absorbed by the third recording layer 70 are substantially equal, and the power of the laser beam LB irradiated via the light transmitting layer 45 is: The second recording layer 60 and the third recording layer 70 are formed such that the light absorption of the second recording layer 60 and the third recording layer 70 has a sufficient light absorption of 10% to 30%. It has been found that Lever, in any of the second recording layer 60 and the third recording layer 70, as desired, it is possible to record the data.

  Furthermore, according to the research of the present inventor, the second recording layer 60 and the third recording layer 70 contain Zn, Si, S and O as main components and are selected from the group consisting of Mg, Al and Ti. The second recording layer 60 and the third recording layer 70 each include at least one metal as an additive, and the second recording layer 60 has a thickness of 15 nm to 50 nm. When formed so that the ratio D3 / D2 of the thickness D3 to the thickness D2 of the second recording layer 60 is 0.40 to 0.70, the reflectance of the second recording layer 60 It has been found that the second recording layer 60 and the third recording layer 70 can be formed such that the reflectances of the third and third recording layers 70 are substantially equal and each has a sufficient reflectance. Therefore, according to this embodiment, the second recording layer 60 and the second Both the even recording layer 70 of the data, as desired, can be reproduced.

  As shown in FIG. 4, on the surface of the third recording layer 70, a light transmitting layer 45 is formed.

  The light transmitting layer 45 is a layer that transmits the laser beam LB, and one surface of the light transmitting layer 45 forms a light incident surface 45a.

  The light transmitting layer 45 is preferably formed to have a thickness of 30 μm to 200 μm.

  As shown in FIG. 4, the main surface of the light transmitting layer 45 facing the third recording layer 70 has a groove formed on the main surface of the second transparent intermediate layer 43 on the third recording layer 70 side. An uneven pattern of G and lands L, that is, an uneven pattern similar to the uneven pattern of grooves G and lands L formed on the main surface of the support substrate 41 on the first recording layer 50 side is formed.

  The light transmitting layer 45 is formed by applying an ultraviolet curable resin solution onto the third recording layer 70 by a spin coating method to form a coating film, and irradiating the surface of the coating film with ultraviolet light to form a coating film. Is cured, and as a result, the concave and convex pattern of the groove G and the land L formed on one main surface of the second transparent intermediate layer 43 on the third recording layer 70 side, that is, the support substrate 41 The concavo-convex pattern of the groove G and the land L formed on one main surface of the first recording layer 50 side is transferred to the main surface of the light transmitting layer 45 facing the third recording layer 70, and the light transmitting layer 45 is formed. An uneven pattern similar to the groove G and the land L formed on the main surface of the support substrate 41 on the first recording layer 50 side is formed on the main surface facing the third recording layer 70.

  The light transmitting layer 45 records data on the first recording layer 50, the second recording layer 60 or the third recording layer 70, and records the data on the first recording layer 50, the second recording layer 60 or the third recording layer 60. When the data recorded on the recording layer 70 is reproduced, the laser beam LB needs to have a sufficiently high light transmittance because the laser beam LB passes therethrough.

  When recording data on the first recording layer 50 of the optical recording disk 40 according to the present embodiment configured as described above, a laser beam LB having a wavelength of 400 nm to 430 nm is transmitted through the light transmission layer 45. Thus, the first recording layer 50 is focused.

  As a result, the first recording layer 50 is heated, and Si contained as a main component in the first recording film 53a and Cu contained as a main component in the second recording film 53b are mixed. , A mixed region is formed. The mixed area formed in this way can be used as a recording mark because the reflectivity of the other blank area to the laser beam LB is significantly different from that of the other blank areas.

  In the present embodiment, each of the second recording layer 60 and the third recording layer 70 contains Zn, Si, S, and O as main components, and at least one kind selected from the group consisting of Mg, Al, and Ti. The second recording layer 60 includes a metal as an additive, has a thickness of 15 nm to 50 nm, and has a ratio of a thickness D3 of the third recording layer 70 to a thickness D2 of the second recording layer 60. Since D3 / D2 is formed to be 0.40 to 0.70, the second recording layer 60 and the third recording layer 70 have a sufficiently high light transmittance for the laser beam LB. Therefore, when the laser beam LB passes through the third recording layer 70 and the second recording layer 60, a decrease in the power of the laser beam LB can be suppressed to a minimum. In the first recording layer 50, , It becomes possible to record data.

  On the other hand, even when data recorded on the first recording layer 50 is reproduced, a decrease in the power of the laser beam LB when transmitting through the third recording layer 70 and the second recording layer 60 is minimized. When the laser beam LB reflected by the first recording layer 50 passes through the second recording layer 60 and the third recording layer 70, the power of the laser beam LB is reduced. Since it is possible to minimize the decrease, the data recorded on the first recording layer 50 can be reproduced as desired.

  Further, in the present embodiment, since the reflection film 51 is formed between the first recording layer 50 and the support substrate 41, the laser beam LB reflected by the reflection film 51 and the first recording layer The laser beam LB reflected by 50 interferes with each other, and as a result, the difference in reflectivity between before and after recording of data can be increased. Therefore, the data recorded on the first recording layer 50 is Reproducible with good sensitivity.

  When data is recorded on the second recording layer 60 of the optical recording disc 40, a laser beam LB having a wavelength of 400 nm to 430 nm is applied to the second recording layer 60 via the light transmitting layer 45. Be focused.

  As a result, the second recording layer 60 is heated, and Zn contained in a simple form in the region of the heated second recording layer 60 reacts with S to become ZnS in a crystalline state. The amorphous ZnS present around the crystalline ZnS grows with the crystalline ZnS as a nucleus. In this manner, the region where ZnS in a crystalline state is generated has a large difference in reflectivity with respect to the laser beam LB having a wavelength λ of 400 nm to 430 nm from the other region, so that it can be used as a recording mark and data can be used. , On the second recording layer 60.

  Further, when data is recorded on the third recording layer 70 of the optical recording disc 40, a laser beam LB having a wavelength of 400 nm to 430 nm is applied to the third recording layer 70 via the light transmitting layer 45. Be focused.

  In the present embodiment, since the third recording layer 70 has the same composition as the second recording layer 60, when the third recording layer 70 is irradiated with the laser beam LB, the laser beam LB The region of the third recording layer 70 irradiated with is crystallized, and data is recorded on the third recording layer 70 similarly to the second recording layer 60.

  In the present embodiment, each of the second recording layer 60 and the third recording layer 70 contains Zn, Si, S, and O as main components, and at least one kind selected from the group consisting of Mg, Al, and Ti. The second recording layer 60 includes a metal as an additive, has a thickness of 15 nm to 50 nm, and has a ratio of a thickness D3 of the third recording layer 70 to a thickness D2 of the second recording layer 60. Since D3 / D2 is formed to be 0.40 to 0.70, the amount of the laser beam LB absorbed by the second recording layer 60 and the laser absorbed by the third recording layer 70 The light absorptance of the second recording layer 20 and the third recording layer 70 is 10% with respect to the power of the laser beam LB irradiated through the light transmitting layer 45 when the amounts of the beams LB are substantially equal. % To 30% of sufficient light The second recording layer 60 and the third recording layer 70 can be formed so as to have a yield, and therefore, any of the second recording layer 60 and the third recording layer 70 The data can be recorded as desired.

  According to the study of the present inventor, as described above, one main surface of the support substrate 41, a main surface of the first transparent intermediate layer 42 facing the light transmitting layer 45, and a light transmission of the second transparent intermediate layer 43. In the optical recording disk 40 in which the groove G and the land L are formed on the main surface opposing the layer 45 and the main surface opposing the support substrate 41 of the light transmitting layer 45, the jitter at the time of data reading is within a desired range. It is possible to suppress the occurrence of an error at the time of data reading, and to maintain the push-pull signal level at or above a desired value, thereby enabling tracking control to be performed as desired. Has been found.

  FIG. 6 is a schematic sectional view of an optical recording disk according to still another preferred embodiment of the present invention.

  As shown in FIG. 6, the optical recording disk 100 according to the present embodiment includes a support substrate 41, a first recording layer 50 formed on the surface of the support substrate 41, and a surface of the first recording layer 50. A first transparent intermediate layer 42 formed thereon, a second recording layer 60 formed on the surface of the first transparent intermediate layer 42, and a second recording layer 60 formed on the surface of the second recording layer 60. A second transparent intermediate layer 43, a third recording layer 70 formed on the surface of the second transparent intermediate layer 43, and a third transparent intermediate layer 44 formed on the surface of the third recording layer 70; A fourth recording layer 80 formed on the surface of the third transparent intermediate layer 44, and a light transmitting layer 45 formed on the surface of the fourth recording layer 80. 4 and 5 except that the transparent intermediate layer 44 and the fourth recording layer 80 are formed and the recording layer has a four-layer structure. It has the same configuration as that of the optical recording disc 40.

  The third transparent intermediate layer 44 plays a role of physically and optically separating the third recording layer 70 and the fourth recording layer 80 from each other with a sufficient distance.

  Similarly to the optical recording disk 40 shown in FIGS. 4 and 5, in the optical recording disk 100 according to the present embodiment, the light transmission of the one main surface of the support substrate 41 and the first transparent intermediate layer 42 is also performed. The main surface facing the layer 45, the main surface facing the light transmitting layer 45 of the second transparent intermediate layer 43, and the main surface facing the light transmitting layer 45 of the third transparent intermediate layer 44 have a substantially trapezoidal shape. Grooves G having a cross section and lands L having a substantially trapezoidal cross section are alternately formed. Also in the present embodiment, the groove G and the land L have a depth Gd of the groove G of 15 nm or more and 25 nm or less. The half width Gw of the groove G is formed to be 150 nm or more and 230 nm or less, and the angle θ of the inclined surface between the adjacent groove G and the land L with respect to one main surface of the support substrate 2 is 12 ° or more. 30 ° It is sea urchin formation.

  Further, on the main surface of the third transparent intermediate layer 44 facing the light transmitting layer 45, the same concavo-convex pattern as the plurality of grooves G and lands L formed on one main surface of the support substrate 41 is formed. I have.

  The third transparent intermediate layer 44 is formed by applying a UV curable resin solution on the third recording layer 70 by a spin coating method to form a coating film, and forming the support substrate 41 on the surface of the coating film. It is formed by irradiating ultraviolet rays through the stamper with a stamper (not shown) in which the same concavo-convex pattern as the stamper (not shown) used for forming is formed. On the main surface of the third transparent intermediate layer 44 facing the light transmitting layer 45, the same concavo-convex pattern as the plurality of grooves G and lands L formed on one main surface of the support substrate 41 is formed.

  Further, also in the present embodiment, the groove G and the land L are formed such that the wobble amount Wob is ± 7 nm to ± 25 nm.

  The third transparent intermediate layer 44 is preferably formed to have a thickness of 5 μm to 50 μm, and is more preferably formed to have a thickness of 10 μm to 40 μm.

The fourth recording layer 80 is formed by vapor deposition such as sputtering using a target made of a mixture of ZnS and SiO ₂ and a target made of at least one metal selected from the group consisting of Mg, Al and Ti. By the method, it is formed on the surface of the third transparent intermediate layer 44.

  In the present embodiment, the same target as that used when forming the second recording layer 60 and the third recording layer 70 is used, and therefore, the fourth recording layer 80 is formed by the second recording layer 60 and the third recording layer 70. It has the same composition as the third recording layer 70.

  In the present embodiment, the second recording layer 60 has a thickness of 20 nm to 50 nm, and the thickness D3 of the third recording layer 70 and the thickness D2 of the second recording layer 60 are different from each other. The ratio D3 / D2 is 0.48 to 0.93, and the ratio D4 / D2 of the thickness D4 of the fourth recording layer 80 to the thickness D2 of the second recording layer 60 is 0.39 to 0.70. The second recording layer 60 has a thickness D2, a third recording layer 70 has a thickness D3 and a fourth recording layer 80 has a thickness D4 that satisfies D2> D3> D4. A recording layer 60, a third recording layer 70, and a fourth recording layer 80 are formed.

  According to the study of the inventor, the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 contain Zn, Si, S, and O as main components, respectively, and contain Mg, Al, It contains at least one metal selected from the group consisting of Ti as an additive, and has a thickness D2 of the second recording layer 60, a thickness D3 of the third recording layer 70, and a thickness D4 of the fourth recording layer 80. , D2> D3> D4, the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 emit light sufficiently high with respect to the laser beam LB. It has been found that the laser beam LB passes through the fourth recording layer 80, the third recording layer 70, and the second recording layer 60 according to the present embodiment. In addition, the power of the laser beam LB is minimized from being reduced. Win it possible, in the first recording layer 50, as desired, it is possible to record the data. On the other hand, also when reproducing data recorded on the first recording layer 50, when the laser beam LB passes through the second recording layer 60, the third recording layer 70, and the fourth recording layer 80, , The power of the laser beam LB can be suppressed to a minimum, and the laser beam LB reflected by the first recording layer 50 is applied to the second recording layer 60 and the third recording layer 70. In addition, when the laser beam LB passes through the fourth recording layer 80, it is possible to minimize a decrease in the power of the laser beam LB. Thus, it becomes possible to reproduce.

  According to the study of the present inventor, the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 are respectively replaced by the second recording layer 60, the third recording layer 70, and the fourth recording layer 70. The fourth recording layer 80 includes Zn, Si, S, and O as main components, at least one metal selected from the group consisting of Mg, Al, and Ti as an additive. When the thickness D2, the thickness D3 of the third recording layer 70, and the thickness D4 of the fourth recording layer 80 are formed so as to satisfy D2> D3> D4, it is far from the light incident surface 45a. It has been found that the greater the number of recording layers, the higher the reflectivity with respect to the laser beam LB. Therefore, according to this embodiment, not only the first recording layer 50 but also the second recording layer 60 is used. , Third recording layer 70 and fourth recording layer 8 From also data, as desired, it can be reproduced.

  Further, according to the study of the present inventor, the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 each contain Zn, Si, S, and O as main components, The second recording layer 60 includes at least one metal selected from the group consisting of Al and Ti as an additive, has a thickness of 20 nm to 50 nm, has a thickness D3 of the third recording layer 70, The ratio D3 / D2 to the thickness D2 of the second recording layer 60 is 0.48 to 0.93, and the thickness D4 of the fourth recording layer 80 and the thickness D2 of the second recording layer 60 are different from each other. Is formed so that the ratio D4 / D2 becomes 0.39 to 0.70, the amount of the laser beam LB absorbed by the second recording layer 60 and the amount of laser beam LB absorbed by the third recording layer 70 The amount of the laser beam LB absorbed and absorbed by the fourth recording layer 80. The amount of the laser beam LB is substantially equal, and the second recording layer 60, the third recording layer 70, and the fourth recording layer are applied to the power of the laser beam LB irradiated through the light transmitting layer 45. The second recording layer 60, the third recording layer 70, and the fourth recording layer 80 can be formed so that the light absorption of the layer 80 has a sufficiently high light absorption of 10% to 20%. Therefore, data can be recorded on any of the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 as desired. It becomes.

  According to the study of the present inventors, the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 each contain Zn, Si, S, and O as main components, The second recording layer 60 includes at least one metal selected from the group consisting of Al and Ti as an additive, has a thickness of 20 nm to 50 nm, has a thickness D3 of the third recording layer 70, The ratio D3 / D2 to the thickness D2 of the second recording layer 60 is 0.48 to 0.93, and the thickness D4 of the fourth recording layer 80 and the thickness D2 of the second recording layer 60 are different from each other. Are formed so that the ratio D4 / D2 is 0.39 to 0.70, the reflectivity of the second recording layer 60, the reflectivity of the third recording layer 70, and the fourth recording layer 80 so that the reflectivity of the second record is approximately equal and each has sufficient reflectivity. 60, the third recording layer 70 and the fourth recording layer 80 have been found to be able to form, and therefore the second recording layer 60, the third recording layer 70 and the fourth recording layer 80 From any of the recording layers, the recorded data can be reproduced as desired.

  According to the study of the present inventor, as described above, one main surface of the support substrate 2, a main surface of the first transparent intermediate layer 42 opposed to the light transmitting layer 45, and a light transmission of the second transparent intermediate layer 43. In the optical recording disk 100 in which the groove G and the land L are formed on the main surface opposing the layer 45 and the main surface opposing the light transmitting layer 45 of the third transparent intermediate layer 44, jitter during data reading is desired. , It is possible to suppress the occurrence of errors during data reading, and it is possible to maintain the push-pull signal level at or above a desired value, and perform tracking control as desired. Has been found to be possible.

  Hereinafter, examples will be given to further clarify the effects of the present invention.

Example 1
Stampers # 1 to # 19 on which grooves having different depths were formed were prepared as follows.

  First, a coupling agent layer is formed on a polished glass substrate, and a photoresist is applied on the coupling agent layer by a spin coating method, and baked at 85 ° C. for 20 minutes to remove residual solvent. Was removed to form a 12-nm-thick photoresist layer.

  Next, the photoresist layer was exposed to light using a cutting machine manufactured by Sony Corporation with a track pitch of 320 nm and a deep ultraviolet laser (wavelength: 266 nm).

  Thereafter, development was performed to obtain a photoresist master having a groove width of 170 nm.

Next, a nickel thin film was formed on the surface of the photoresist layer of the photoresist master by electroless plating.
Further, using a nickel thin film as a base, electroforming was performed to form a nickel electroformed film, which was peeled off from the photoresist master to prepare a master disk.

Next, the surface of the master disk is immersed in a KMnO ₄ solution and oxidized, an electroformed film is formed, and the electroformed film is peeled off from the surface of the master disk. Motherboard was obtained.

  The motherboard thus obtained was punched out and polished on the back surface to produce a stamper # 1.

  By changing the thickness of the photoresist layer, stampers # 2 to # 19 having different groove depths Gd were manufactured in the same manner as stamper # 1.

  Using the stampers # 1 to # 19 thus manufactured, the optical recording disk shown in FIG. 1 was manufactured as follows.

  A polycarbonate substrate having a diameter of 120 mm and a thickness of 1.1 mm was prepared by injection molding, and formed on the surface of the polycarbonate substrate using the stampers # 1 to # 19, respectively, for the stampers # 1 to # 19. The grooves and lands were transferred to form the grooves and lands on the surface of the polycarbonate substrate.

  Further, a reflection layer of Ag, Pd and Cu (atomic ratio 98: 1: 1) with a thickness of 100 nm was formed on the surface of the polycarbonate substrate by a sputtering method.

Next, a 28-nm-thick second dielectric layer was formed on the surface of the reflective layer by a sputtering method using a target made of ZnS (80 mol%)-SiO ₂ (20 mol%).

  Further, a second recording layer of CuAl having a thickness of 6 nm was formed on the surface of the second dielectric layer by a sputtering method.

  Next, a first recording layer having a thickness of 6 nm and containing Si as a main component was formed on the surface of the second recording layer.

Further, a first dielectric layer having a thickness of 25 nm was formed on the surface of the first recording layer by a sputtering method using a target composed of ZnS (80 mol%)-SiO ₂ (20 mol%).

  Further, an ultraviolet curable resin solution is applied to the surface of the second dielectric layer by a spin coating method to form a coating film, and the coating film is irradiated with ultraviolet light to cure the ultraviolet curable resin, A light transmitting layer having a thickness of 100 μm was formed.

  Thus, optical recording disk samples # 1 to # 19 on which grooves having different depths Gd were formed were obtained.

  Next, using an evaluation device, a laser beam having a wavelength of 405 nm is irradiated on each of the optical recording disk samples # 1 to # 19 via an objective lens having a numerical aperture NA of 0.85, and each sample is pushed. The pull signal was measured, and the jitter of a signal recorded continuously for 5 tracks on the recording layer of optical recording disk samples # 1 to # 19 was measured.

  FIG. 7 shows the result of measuring the relationship between the groove depth Gd and the jitter, and FIG. 8 shows the result of measuring the relationship between the groove depth Gd and the push-pull signal.

  As shown in FIG. 7, when the groove depth Gd is 25 nm or less, the jitter can be suppressed to 10% or less, so that the reproduced signal is stabilized, and the occurrence of an error during data reading is suppressed. It turned out to get.

  Further, as shown in FIG. 8, it was found that when the groove depth was less than 15 nm, the level of the push-pull signal was too small, and it was difficult to perform stable tracking control.

  Therefore, from the first embodiment, a groove having a groove depth Gd of 15 nm or more and 25 nm or less is formed in order to suppress jitter to 10% or less and to enable tracking control as desired. It turns out that it is necessary.

Example 2
As described below, a stamper # 20 in which grooves having different half widths Gw were formed for each zone was prepared.

  First, a coupling agent layer is formed on a polished glass substrate, and a photoresist is applied on the coupling agent layer by a spin coating method, and baked at 85 ° C. for 20 minutes to remove residual solvent. Was removed to form a 22-nm-thick photoresist layer.

  Next, the photoresist layer was exposed to light using a cutting machine manufactured by Sony Corporation with a track pitch of 320 nm and a deep ultraviolet laser (wavelength: 266 nm). Here, the exposure was performed by changing the power of the far ultraviolet laser for each zone of the photoresist layer.

  Thereafter, development was performed to obtain a photoresist master having grooves formed with different half widths Gw for each zone.

  Using the photoresist master thus obtained, a stamper # 20 was produced in the same manner as in Example 1.

  A groove having a groove depth Gd of 20 nm was formed on the stamper # 20 thus manufactured.

  Next, an optical recording disk sample # 20 was produced in the same manner as in Example 1 using the stamper # 20.

  The push-pull signal of the optical recording disk sample # 20 thus manufactured was measured, and further, the jitter of a signal obtained by continuously recording five tracks on the recording layer of the optical recording disk sample # 20 was measured.

  The measurement results are shown in FIG. 9 and FIG.

  FIG. 9 is a graph showing the result of measuring the relationship between the half width Gw of the groove and the jitter, and FIG. 10 is a graph showing the result of measuring the relationship between the half width Gw of the groove and the push-pull signal. In FIGS. 9 and 10, the horizontal axis is the half width Gw of the groove measured by the scanning electron microscope.

  As shown in FIG. 9, it was found that the larger the half width Gw of the groove was, the smaller the jitter was. On the other hand, when the half width Gw of the groove was less than 150 nm, the jitter was worse and exceeded 10%.

  Further, as shown in FIG. 10, the larger the half-width Gw of the groove, the lower the level of the push-pull signal. If the half-width Gw of the groove exceeds 230 nm, the level of the push-pull signal becomes too small, and It has been found that it becomes difficult to perform the tracking control described above.

  Therefore, from the second embodiment, in order to suppress jitter to 10% or less and to enable tracking control as desired, a groove having a half width Gw of 150 nm or more and 230 nm or less must be formed. Is necessary.

Example 3
A stamper # 21 having a different wobble amount Wob for each zone was manufactured as follows.

  First, a coupling agent layer is formed on a polished glass substrate, and a photoresist is applied on the coupling agent layer by a spin coating method, and baked at 85 ° C. for 20 minutes to remove residual solvent. Was removed to form a 20-nm-thick photoresist layer.

  Then, using a cutting machine manufactured by Sony Corporation, the photoresist layer was exposed to light with a track pitch of 320 nm using a deep ultraviolet laser (wavelength: 266 nm) such that the half width Gw of the groove became 170 nm after development.

  At this time, the wobble amount was changed by changing the voltage input to the wobble setting circuit of the cutting machine. The wobble frequency at this time was set to 1 MHz.

  Thereafter, development was performed to obtain a photoresist master having grooves formed with different wobble amounts for each zone.

  Using the photoresist master thus obtained, a stamper # 21 was manufactured in the same manner as in Example 1.

  A groove having a groove depth Gd of 18 nm was formed on the stamper # 21 thus manufactured.

Using the stamper # 21 thus obtained, an optical recording disk sample # 21 was produced in the same manner as in Example 1.
The wobble signal / noise ratio of the optical recording disk sample # 21 thus manufactured was evaluated using the evaluation apparatus used in Example 1.

  The evaluation conditions were as follows.

Resolution bandwidth (RBW: Resolution Band Width): 3 kHz
The result of evaluating the relationship between the wobble amount Wob and the wobble signal / noise ratio (wobble C / N ratio) is shown in FIG.

  As shown in FIG. 11, it has been found that a good wobble signal / noise ratio (wobble C / N ratio) can be obtained by forming a groove and a land so that the wobble amount Wob becomes ± 7 nm or more. did.

  On the other hand, the tracking error signal was input to the oscilloscope from the evaluation device used in Example 1, and the residual tracking error component with respect to the wobble amount Wob was measured for the optical recording disk sample # 21.

  The measurement results are shown in FIG.

  As shown in FIG. 12, it was found that when the wobble amount Wob exceeds ± 25 nm, the residual tracking error increases.

  Therefore, from Example 3, in order to obtain a good wobble signal / noise ratio (wobble C / N ratio), it is necessary to form grooves and lands so that the wobble amount Wob is ± 7 nm or more. In order to suppress the residual tracking error to a low value, it has been found that it is necessary to form the groove and the land so that the wobble amount Wob is ± 25 nm or less.

  The present invention is not limited to the above embodiments and examples, and various modifications can be made within the scope of the invention described in the claims, which are also included in the scope of the present invention. It goes without saying that it is a thing.

  For example, in the above embodiment, grooves G having a substantially trapezoidal cross section and lands L having a substantially trapezoidal cross section are alternately formed on one main surface of the support substrate 2. It is not always necessary to alternately form a groove G having a substantially trapezoidal cross section and a land L having a substantially trapezoidal cross section on the main surface of.

  Further, in the above embodiment, the groove G and the land L are formed so that the angle θ between the adjacent groove G and the land L with respect to the main surface of the support substrate 2 is 12 ° to 30 °. However, it is not possible to form the groove G and the land L such that the angle θ of the inclined surface between the adjacent groove G and the land L with respect to the main surface of the support substrate 2 is 12 ° to 30 °. Not necessarily.

  Further, in the above embodiment, the groove G and the land L are formed so that the wobble amount Wob is ± 7 nm to ± 25 nm, but the wobble amount Wob is ± 7 nm to ± 25 nm. It is not always necessary to form the groove G and the land L.

  In the embodiment shown in FIGS. 1 and 2, the light transmitting layer 9 is formed by applying an ultraviolet curable resin solution to the surface of the first dielectric layer 8 by a spin coating method. The coating film is formed by irradiating an ultraviolet ray to the coating film to cure the ultraviolet curable resin, and the main surface of the light transmitting layer 9 facing the support substrate 2 is provided on one main surface of the support substrate 2. The shapes of the formed grooves G and lands L are transferred, and the same concavo-convex pattern as the grooves G and lands L formed on one main surface of the support substrate 2 is formed. In the above, the light transmitting layer 13 is formed by applying a UV curable resin solution to the surface of the L1 layer 30 by a spin coating method to form a coating film, and irradiating the coating film with UV light to form The light transmitting layer is formed by curing the resin. The shape of the groove G and the land L formed on one main surface of the support substrate 11 is transferred to the main surface of the support substrate 11 facing the third support substrate 11, and the groove G formed on one main surface of the support substrate 11 is transferred. 4 and 5, and in the embodiment shown in FIGS. 4 and 5, the light transmitting layer 45 is formed by applying an ultraviolet curable resin solution on the surface of the third recording layer 70. A main surface of the light transmitting layer 45, which is formed by applying a spin coating method to form a coating film, and irradiating the coating film with ultraviolet rays to cure the ultraviolet curable resin, and faces the support substrate 41 of the light transmitting layer 45 The shape of the groove G and the land L formed on one main surface of the support substrate 41 is transferred, and the same concavo-convex pattern as the groove G and the land L formed on one main surface of the support substrate 41 is formed. Have beenHowever, the light-transmitting layers 9, 13, and 45 are applied to the surface of the first dielectric layer 8, the L1 layer 30, the third recording layer 70, or the fourth recording layer 80 by spin coating with an ultraviolet-curable resin solution. It is not absolutely necessary to form the first dielectric layer 8, the L1 layer 30, the third recording layer 70 or the fourth recording layer 80 on the surface of the first dielectric layer 8, the L1 layer 30, or the fourth recording layer 80. May be adhered to form the light transmitting layers 9, 13, 45. When the light transmitting layers 9, 13, and 45 are formed in this manner, the main surfaces of the light transmitting layers 9, 13, and 45 facing the support substrates 2, 11, and 41 support the support substrates 2, 11, and 41. The shapes of the groove G and the land L formed on one of the main surfaces are not transferred.

  Further, in the embodiment shown in FIGS. 1 and 2, the first recording film 6 is disposed on the light transmitting layer 9 side, and the second recording film 5 is disposed on the support substrate 2 side. The first recording film 6 may be disposed on the support substrate 2 side, and the second recording film 5 may be disposed on the light transmission layer 9 side.

  Further, in the embodiment shown in FIG. 3, the first L1 recording film 33a containing Si as a main component is disposed on the light transmission layer 13 side, and the second L1 recording film 33b containing Cu as a main component is formed. Although disposed on the support substrate 11 side, the first L1 recording film 33a containing Si as a main component is disposed on the support substrate 11 side, and the second L1 recording film 33b containing Cu as a main component transmits light. It may be arranged on the layer 13 side.

  Further, in the embodiment shown in FIG. 3, a first L0 recording film 23a containing Si as a main component is disposed on the light transmission layer 13 side, and a second L0 recording film 23b containing Cu as a main component is formed. Although disposed on the support substrate 11 side, the first L0 recording film 23a containing Si as a main component is disposed on the support substrate 11 side, and the second L0 recording film 23b containing Cu as a main component transmits light. It may be arranged on the layer 13 side.

  In the embodiment shown in FIG. 3, the L0 layer 20 includes a first L0 recording film 23a containing Si as a main component and a second L0 recording film 23b containing Cu as a main component. However, it is not always necessary for the L0 layer 20 to include the first L0 recording film 23a containing Si as a main component and the second L0 recording film 23b containing Cu as a main component. May be constituted by a single recording film. Further, the L0 layer 20 may be configured as a read-only recording layer by pre-pits formed on the surface of the support substrate 11.

Further, in the embodiment shown in FIGS. 4 and 5 and the embodiment shown in FIG. 6, the second recording layer 60, the third recording layer 70 and the fourth recording layer of the optical recording disks 40 and 100 are provided. Each of the layers 80 is formed by a vapor deposition method such as a sputtering method using a target composed of a mixture of ZnS and SiO ₂ and a target composed of at least one metal selected from the group consisting of Mg, Al, and Ti. The second recording layer 60, the third recording layer 70, and the fourth recording layer 80 of the optical recording disks 40 and 100 are formed by combining a target made of a mixture of ZnS and SiO ₂ with Mg, It is indispensable to form by a vapor phase growth method such as a sputtering method using a target made of at least one metal selected from the group consisting of Al and Ti. Not necessary, by using a target containing a target comprising a mixture of ZnS and SiO ₂ as a main component, Mg, at least one metal selected from the group consisting of Al and Ti as a main component, the gas such as a sputtering method The second recording layer 60, the third recording layer 70, and the fourth recording layer 80 can also be formed by the phase growth method.

In the embodiments shown in FIGS. 4 and 5 and the embodiment shown in FIG. 6, the second recording layer 60, the third recording layer 70 and the fourth recording layer of the optical recording disks 40 and 100 are used. Each of the layers 80 is formed by a vapor deposition method such as a sputtering method using a target composed of a mixture of ZnS and SiO ₂ and a target composed of at least one metal selected from the group consisting of Mg, Al, and Ti. As a result, the optical recording disk 40 contains Zn, Si, S, and O as main components and contains at least one metal selected from the group consisting of Mg, Al, and Ti as an additive. second recording layer 60 of 100, the third recording layer 70 and the fourth recording layer 80, and a target made of a mixture of ZnS and SiO _2, Mg, Al Oyo The second recording layer of the optical recording disks 40 and 100 is not necessarily formed by a vapor growth method such as a sputtering method using a target made of at least one metal selected from the group consisting of Ti. 60, the third recording layer 70 and the fourth recording layer 80 are selected from the group consisting of a target mainly containing a mixture of La ₂ O ₃ , SiO ₂ and Si ₃ N ₄ and Mg, Al and Ti. It can also be formed by a vapor deposition method using a target containing at least one metal as a main component. When the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 of the optical recording disks 40, 100 are formed in this manner, the second recording layer 60, the third recording layer The layer 70 and the fourth recording layer 80 each contain La, Si, O and N as main components, and contain at least one metal selected from the group consisting of Mg, Al and Ti as an additive.

  Further, in the embodiment shown in FIGS. 4 and 5 and the embodiment shown in FIG. 6, the second recording layer 60, the third recording layer 70 and the fourth recording layer of the optical recording disks 40 and 100 are provided. The layer 80 has the same composition, but the difference in the content of Zn, Si, O, and S between the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 is different. 5 atomic% or less, and it is not always necessary that the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 of the optical recording disks 40 and 100 have the same composition. Not.

  Further, in the embodiment shown in FIGS. 4 and 5, the second recording layer 60 and the third recording layer 70 of the optical recording disk 40 each contain Zn, Si, S and O as main components. , Mg, Al, and Ti as additives, the second recording layer 60 and the third recording layer 70 of the optical recording disk 40 are Zn, Si, respectively. , S and O as main components, and it is not always necessary to include at least one kind of metal selected from the group consisting of Mg, Al and Ti as an additive. And at least one layer of the third recording layer 70 is composed of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and La. If it contains at least one selected metal M and an element X that is combined with the metal M by being irradiated with the recording laser beam LB to form a crystal of a compound with the metal M. Preferably, at least one of the second recording layer 60 and the third recording layer 70 of the optical recording disk 40 is made of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi. , Containing at least one metal selected from the group consisting of Zn and La and at least one element selected from the group consisting of S, O, C and N as main components, and selected from the group consisting of Mg, Al and Ti At least one metal may be included as an additive.

  In the embodiment shown in FIG. 6, the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 of the optical recording disk 100 are made of Zn, Si, S, and O, respectively. It contains at least one metal selected from the group consisting of Mg, Al, and Ti as an additive, but contains at least one of the second recording layer 60, the third recording layer 70, and the fourth recording layer of the optical recording disk 100. It is not necessary that each of the recording layers 80 include Zn, Si, S, and O as main components and at least one metal selected from the group consisting of Mg, Al, and Ti as an additive. At least one of the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 of the optical recording disk 100 includes Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, and In. At least one kind of metal M selected from the group consisting of Sn, W, Pb, Bi, Zn, and La, and by being irradiated with a recording laser beam LB, combined with the metal M and At least one of the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 of the optical recording disk 100 may include Ni, Cu, and the like. At least one metal selected from the group consisting of Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn and La, and selected from the group consisting of S, O, C and N At least one element may be included as a main component, and at least one metal selected from the group consisting of Mg, Al, and Ti may be included as an additive.

  Further, in the embodiment shown in FIGS. 4 and 5, and in the embodiment shown in FIG. 6, an optical recording disk is formed by using a target made of at least one metal selected from the group consisting of Mg, Al and Ti. Although the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 of 40 and 100 are formed, a target made of at least one metal selected from the group consisting of Mg, Al and Ti Alternatively, the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 of the optical recording disks 40 and 100 can be formed using a target containing Zn or La as a main component.

  Further, in the embodiment shown in FIGS. 4 and 5, the optical recording disk 40 includes a substrate 41, a light transmitting layer 45, and a first recording layer formed between the substrate 41 and the light transmitting layer 45. In the embodiment shown in FIG. 6, the optical recording disk 100 comprises a substrate 41, a light transmitting layer 45, a substrate 41 and a light transmitting layer 50, a second recording layer 60 and a third recording layer 70. The first recording layer 50, the second recording layer 60, the third recording layer 70, and the fourth recording layer 80 formed between the layers 45 are provided. The present invention is not limited to an optical recording disk having a recording layer and an optical recording disk having four recording layers, but can be widely applied to an optical recording disk having two or more recording layers.

  Further, in the embodiment shown in FIGS. 4 and 5, and in the embodiment shown in FIG. 6, the first recording layer 50 of the optical recording disks 40 and 100 has the first recording layer containing Cu as a main component. The optical recording disks 40 and 100 have a first recording layer 50 containing Cu as a main component, which has a film 53a and a second recording film 53b containing Si as a main component. It is not always necessary to form the first recording layer 50 of the optical recording disks 40 and 100 with Ni, Cu, Si, Ti, Ge. , Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and at least one metal selected from the group consisting of La and at least one element selected from the group consisting of S, O, C, and N With the main component At least one metal selected from the group consisting of Mg, Al and Ti can be formed so as to include an additive. Further, Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In , Sn, W, Pb, Bi, Zn, and at least one metal M selected from the group consisting of La and a laser beam LB for recording are applied to combine with the metal M, And an element X that forms a crystal of the compound of formula (1).

  In the embodiments shown in FIGS. 4 and 5 and the embodiment shown in FIG. 6, the first recording layer 50 of the optical recording disks 40 and 100 has the first recording layer containing Cu as a main component. It has a film 53a and a second recording film 53b containing Si as a main component. However, instead of the first recording layer 50, a pit is formed on the surface of the support substrate 41 or the first transparent intermediate layer 42. May be formed and the data is recorded, so that the support substrate 41 or the first transparent intermediate layer 42 may be used as a read-only recording layer.

FIG. 1 is an enlarged sectional view of a substantial part of an optical recording disk according to a preferred embodiment of the present invention. FIG. 2 is a schematic sectional view showing details of the sectional shapes of the groove and the land. FIG. 3 is a schematic sectional view of an optical recording disk according to another preferred embodiment of the present invention. FIG. 4 is a schematic sectional view of an optical recording disk according to another preferred embodiment of the present invention. FIG. 5 is a schematic enlarged sectional view of a first recording layer of the optical recording disc shown in FIG. FIG. 6 is a schematic perspective view of an optical recording disk according to still another preferred embodiment of the present invention. FIG. 7 is a graph showing the result of measuring the relationship between the groove depth Gd and the jitter in Example 1. FIG. 8 is a graph showing the result of measuring the relationship between the groove depth Gd and the push-pull signal in the first embodiment. FIG. 9 is a graph showing the result of measuring the relationship between the half width Gw of the groove and the jitter in the second embodiment. FIG. 10 is a graph showing the result of measuring the relationship between the half width Gw of the groove and the push-pull signal in the second embodiment. FIG. 11 is a graph showing the result of evaluating the relationship between the wobble amount Wob and the wobble signal / noise ratio in the third embodiment. FIG. 12 is a graph showing the result of measuring the relationship between the wobble amount Wob and the tracking error (residual noise) in the third embodiment.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Optical recording disk 2 Support substrate 3 Reflective layer 4 Second dielectric layer 5 Second recording film 6 First recording film 7 Recording layer 8 First dielectric layer 9 Light transmission layer 10 Optical recording disk 11 Support substrate 12 Transparent intermediate layer 13 Light transmitting layer 13a Light incident surface 20 L0 layer 21 Reflecting film 22 Fourth dielectric film 23 L0 recording layer 23a First L0 recording film 23b Second L0 recording film 23b
24 third dielectric film 30 L1 layer 31 reflection film 32 second dielectric film 33 L1 recording layer 33a first L1 recording film 33b second L1 recording film 34 first dielectric film 40 optical recording disk 41 Support substrate 42 First transparent intermediate layer 43 Second transparent intermediate layer 43 Third transparent intermediate layer 45 Light transmitting layer 45a Light incident surface 50 First recording layer 51 Reflective film 52 Second dielectric film 53a Second Recording film 53b First recording film 54 First dielectric film 60 Second recording layer 70 Third recording layer 80 Fourth recording layer 100 Optical recording disk G Groove L Land LB Laser beam

Claims (16)

A support substrate, and grooves and lands alternately formed on one main surface of the support substrate; and at least one layer formed on the one main surface of the support substrate on which the grooves and lands are formed. An optical recording disk including an optical functional layer including a recording layer and a light transmitting layer formed on the optical functional layer,
The grooves and the lands are formed so that the depth Gd of each groove is 15 nm or more and 25 nm or less, and the half width Gw of the groove is 150 nm or more and 230 nm or less, and the at least one recording layer is made of an inorganic material. An optical recording disk comprising an element. The optical recording disk according to claim 1, wherein the groove has a substantially trapezoidal cross section, and the land has a substantially trapezoidal cross section. The groove and the land are formed such that an angle θ of the inclined surface between each groove and the adjacent land to the support substrate is 12 ° or more and 30 ° or less. 3. The optical recording disc according to 2. 4. The optical recording disk according to claim 1, wherein the groove and the land are formed such that a wobble amount Wob is equal to or more than ± 7 nm. The optical recording disk according to claim 4, wherein the groove and the land are formed such that a wobble amount Wob is within a range of ± 7 nm to ± 25 nm. A first recording film in which the at least one recording layer contains, as a main component, one element selected from the group consisting of Si, Ge, Sn, Mg, C, Al, Zn, In, Cu, Ti, and Bi; The second recording layer is provided in the vicinity of the first recording film and is selected from the group consisting of Cu, Al, Zn, Ag, Ti, and Si, and contains, as a main component, an element different from the element contained in the first recording film. 6. The optical recording disk according to claim 1, wherein the optical recording disk is constituted by two recording films. The optical recording disk according to claim 6, wherein the second recording film is formed so as to be in contact with the first recording film. An element selected from the group consisting of Cu, Al, Zn, Ag, Mg, Sn, Au, Ti and Pd in the second recording film, and an element contained as a main component in the second recording film; 8. The optical recording disk according to claim 6, wherein a different element is added. 9. The optical recording disk according to claim 6, wherein the first recording film contains, as a main component, an element selected from the group consisting of Si, Ge, and Sn. The optical recording disk according to any one of claims 6 to 9, wherein the second recording film contains Cu as a main component. The optically functional layer includes a plurality of recording layers stacked at least via an intermediate layer, and among the plurality of recording layers, at least one recording layer different from the recording layer farthest from the light transmitting layer, At least one metal M selected from the group consisting of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn, and La, and a recording laser beam are irradiated. The optical recording according to any one of claims 1 to 5, further comprising an element X that forms a crystal of a compound with the metal M by being combined with the metal M. disk. The optical recording disk according to claim 11, wherein the element X is composed of at least one element selected from the group consisting of S, O, C, and N. 13. The method according to claim 11, wherein at least one recording layer containing the metal M and the element X further contains at least one metal selected from the group consisting of Mg, Al, and Ti. Optical recording disc. The optically functional layer includes a plurality of recording layers stacked at least via an intermediate layer, and among the plurality of recording layers, at least one recording layer different from the recording layer farthest from the light transmitting layer, 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, and S, O, C and N 6. The composition according to claim 1, wherein the composition contains at least one element selected from the group as a main component, and contains at least one metal selected from the group consisting of Mg, Al and Ti as an additive. Item 2. The optical recording disk according to item 1. 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; , O, C, and N as a main component, and a target containing, as a main component, at least one metal selected from the group consisting of Mg, Al, and Ti. 15. The optical recording disk according to claim 14, wherein the optical recording disk is formed by a vapor deposition method. The at least one recording layer is a target made of a mixture of ZnS and SiO ₂ or a mixture of La ₂ O ₃ , SiO ₂ and Si ₃ N ₄ , and at least one metal selected from the group consisting of Mg, Al and Ti 16. The optical recording disk according to claim 15, wherein the optical recording disk is formed by a vapor deposition method using a target comprising:

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