WO2003034421A1

WO2003034421A1 - Method for manufacturing multi-recording-layer optical recording medium, apparatus for manufacturing multi-recording-layer optical recording medium, and multi-recording-layer optical recording medium

Info

Publication number: WO2003034421A1
Application number: PCT/JP2002/010700
Authority: WO
Inventors: Tsuyoshi Komaki; Tetsuro Mizushima; Jiro Yoshinari
Original assignee: Tdk Corporation
Priority date: 2001-10-15
Filing date: 2002-10-15
Publication date: 2003-04-24
Also published as: TW594721B

Abstract

A method for manufacturing a multi-recording-layer optical recording medium (1) having on one side of a substrate (2) a plurality of layers (L1, L0) each having a recording layer initialized by irradiation of an initialization laser beam (LIN) and a spacer layer formed between the layer (L1) and the layer (L0). The spacer layer (5) is formed with light transmittance to the initialization laser beam (LIN) lower than the light transmittance to a recording/reproduction laser beam. On the formed spacer layer (5), the layer (L0) is formed. The initialization laser beam (LIN) is applied to the formed layer (L0) to initialize it. Thus, layers including the recording layer can be uniformly initialized.

Description

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Method for manufacturing multilayer recording layer type optical recording medium, apparatus for manufacturing multilayer recording layer type optical recording medium, and multilayer recording layer type optical recording medium

Technical field

The present invention relates to a multilayer recording layer type optical recording medium in which a plurality of layers each including a recording layer initialized by light irradiation are laminated on one surface side of a substrate and a spacer layer is formed between each layer. The present invention relates to a manufacturing method, an apparatus for manufacturing a multilayer recording layer type optical recording medium, and a multilayer recording layer type optical recording medium. Background art

Optical recording media are noted for their high density and large capacity, and are used for various purposes. In particular, rewritable optical recording media that allow erasing and re-recording of recorded information can be used to restore and update data, and can be repeatedly rewritten and used, contributing to expanding the use of optical recording media. It is expected to do. As this type of optical recording medium, a magneto-optical recording medium (MO) and a phase change optical recording medium have been developed and commercialized.

Among these, the applicant has already developed an optical recording medium 21 having a layer structure shown in FIG. 5 as a rewritable phase-change optical recording medium utilizing a phase change (hereinafter, also simply referred to as “optical recording medium”). are doing. The optical recording medium 21 is configured such that a reflective layer 3, a recording layer 4, and a cover layer 7 are sequentially laminated on one surface (upper surface in FIG. 1) of the substrate 2. In this case, the base material 2 is formed into a flat plate shape (for example, a disk (disc) shape) having a predetermined thickness by injection molding using a resin material such as polycarbonate. On the surface (upper surface in the figure) of the base material 2, fine irregularities (not shown) such as groups for tracking servo are formed at the time of molding. The reflective layer 3 is formed on the surface of the base material 2 on which fine irregularities are formed using a metal such as Al, Ag, or Ni. The recording layer 4 has a first protective layer 4a, a phase change material layer 4b, and a second protective layer 4c. Each of these layers 4 c, 4 b, 4 a is laminated on the reflective layer 3 in this order. The first protective layer 4 a Oyopi second protective layer 4 c of this, for example, formed by using a dielectric material such as oxide Al Miya Z n S- S i 0 _2, phase-change material layer 4 b Is formed using GeTeSb, InSbTe, or AgGeInSbTe. The cover layer 7 is formed on the first protective layer 4a using a light-transmitting resin material.

In this optical recording medium 21, the recording layer 4 is irradiated with a recording laser beam (for example, a laser beam having a wavelength of 405 nm) from the cover layer 7 side, and the recording layer 4 including the phase change material layer 4b The recording mark is formed and erased by reversibly changing the phase between the amorphous state and the crystalline state. In other words, in the recording layer 4 (particularly, the phase change material layer 4 b), when the recording power laser beam is irradiated, the irradiated portion is heated to a temperature higher than the melting point and then rapidly cooled (quenched). The recording mark is formed in accordance with the recording signal by being amorphous. In addition, when the recording layer 4 is irradiated with the laser beam of the recording layer, the irradiated portion is heated to a temperature higher than the crystallization temperature, and then gradually cooled (gradually cooled) to be crystallized, thereby recording. The mark is deleted. On the other hand, during reproduction, the optical constant between the amorphous state and the crystalline state when irradiated with a laser beam of reproduction power (for example, a laser beam with a wavelength of 405 nm and a lower power than during recording) is irradiated. Data is reproduced by judging the presence or absence of a recording mark using the difference in light reflectivity that changes with the change.

When the optical recording medium 21 is manufactured, first, the base material 2 is formed into a disk shape having fine irregularities such as groups formed on the surface (one surface) by injection molding. Next, after forming the reflective layer 3 on one surface side of the base material 2, the recording layer 4 is formed on the reflective layer 3. At this time, the phase change material layer 4b and the first and second protective layers 4a and 4c are generally formed by a sputtering method. Next, the force-par layer 7 is formed on the recording layer 4 by, for example, spin coating. In this case, the phase change material layer 4b in the recording layer 4 is in an amorphous state immediately after its formation, and Cannot be recorded. Therefore, in order to ship the optical recording medium 21 in an initialized state in which the user can immediately start using the optical recording medium 21, the recording layer 4 (particularly, the phase change material layer) is required in the manufacturing process of the optical recording medium 21. 4 b) needs to be initialized. For this reason, after forming the cover layer 7, the recording layer 4 is initialized. In this case, a high-power laser beam (hereinafter also referred to as “initialization laser beam”) is irradiated from the same direction as the irradiation direction of the reproduction or recording laser beam (direction from the cover layer 7 side). To initialize the recording layer 4. At this time, a laser beam having a different wavelength from the recording or reproducing laser beam is used as the initialization laser beam so that the initialization can be performed efficiently and in a short time and the production efficiency can be improved. Have been used. In general, a laser beam having a wavelength of 810 nm is used as one laser beam for initialization. This initialization laser beam has, for example, a numerical aperture NA (Numerical Aperture) of about 0.4 (for example, The optical recording medium 21 is irradiated through an objective lens having a value of 0.34). Thus, the manufacture of the optical recording medium 21 in which the recording layer 4 has been initialized is completed.

However, it is desired to develop and commercialize an optical recording medium having a larger capacity, and the applicant is developing an optical recording medium 31 having a larger capacity based on the optical recording medium 21. The optical recording medium 31 will be described with reference to FIG. Note that the same components as those of the optical recording medium 21 are denoted by the same reference numerals, and redundant description will be omitted. The optical recording medium 31 is a so-called single-sided multilayer (for example, two layers) recording layer type optical recording medium (hereinafter, also referred to as “multilayer recording layer type optical recording medium”), as shown in FIG. On one side of the material 2 (the upper surface in the figure), an L1 layer including a reflective layer 3 and a recording layer 4, a spacer layer 32 as a light transmitting layer, and a recording layer 6 (hereinafter, referred to as “ L0 layer) and the copper layer 7 are sequentially laminated. In this case, the thickness TH of the spacer layer 32 is usually set to about 20 μπι, and fine irregularities such as groups are formed on the surface on the L0 layer side. The recording layer 6 has a first protective layer 6a, a phase change material layer 6b, and a second protective layer 6c, and these layers 6c, 6b, 6a are In this order, it is laminated on the surface of the spacer layer 32 on which the fine irregularities are formed. In this case, each layer 6a, 6b, 6c is formed of a strictly different material and film thickness from the corresponding layer 4, 4b, 4c, but has the same function. The force-par layer 7 is formed on the L0 layer using a resin material.

Also in this optical recording medium 31, it is necessary to initialize the recording layers 4 and 6 during the manufacturing process. In this case, as shown in FIG. 7, after forming the power bar layer 7 in the same manner as in the optical recording medium 21, the objective lens 11 having the same numerical aperture NA as that at the time of initialization for the optical recording medium 21 is used. And initialize. Specifically, the L1 layer including the recording layer 4 is initialized by irradiating the L1 layer from the cover layer 7 side with the initialization laser beam LIN emitted from the objective lens 11, and then As shown in (1), the L0 layer is initialized by irradiating the L0 layer with an initialization laser beam LIN. Thus, the manufacture of the optical recording medium 31 in which the 1 ^ 1 layer and the 1 ^ 0 layer have been initialized is completed. Disclosure of the invention

As a result of studying the method of manufacturing the above-described multilayer recording layer type optical recording medium, the inventors have found the following points to be improved. That is, in this manufacturing method, as shown in FIG. 7, when the L 0 layer formed on the spacer layer 32 is initialized, the initialization laser beam L IN applied to the L 0 layer is used. A part of the laser beam LPE passes through the L0 layer and the spacer layer 32 to reach the L1 layer, and a part of the laser beam LRE is reflected by the L1 layer. You. In this case, interference occurs due to unevenness in the thickness of the spacer layer 32 between the reflected laser beam LRE and the laser beam L IN applied to the L 0 layer. For this reason, the amount of light absorbed by the L0 layer partially differs, and as a result, the amount of heat generated differs for each part of the L0 layer (heat generation unevenness occurs in the L0 layer). Therefore, due to the re-irradiation of the reflected laser beam LRE, the crystal state of the L0 layer, in particular, the phase change material layer 6b in the recording layer 6 may be uneven and the LO layer may not be properly initialized. , It is better to improve this point New

The present invention has been made to solve the above-mentioned points to be improved, and a method for manufacturing a multilayer recording layer type optical recording medium capable of uniformly initializing each layer including a recording layer, and a multilayer recording layer type optical recording medium. A main object is to provide a recording medium manufacturing apparatus and a multilayer recording layer type optical recording medium.

In the method for manufacturing a multilayer recording layer type optical recording medium according to the present invention, a plurality of layers each including a recording layer initialized by light irradiation are formed on one surface side of a base material, and a space is formed between the respective layers. A method for manufacturing a multilayer recording layer type optical recording medium, wherein a light transmittance for an initialization laser beam is lower than a light transmittance for a recording laser beam and a reproduction laser beam. A spacer layer is formed, the layer is formed on the formed spacer layer, and the formed layer is initialized by irradiating the laser beam for initialization.

In this case, the spacer is so adjusted that the light transmittance for the initialization laser beam is 70% or less and the light transmittance for the recording laser beam and the reproduction laser beam is 80% or more. Preferably, a layer is formed. Further, light having a wavelength of less than 500 nm is used as the recording laser beam and the reproduction laser beam, and light having a wavelength of 500 nm or more and 100 nm or less is used as the initialization laser beam. It is preferably used. Further, it is preferable that the spacer layer is formed of a spacer layer material to which an infrared absorbing material is added. Further, it is preferable that the recording layer is formed of a phase change material.

In the apparatus for manufacturing a multilayer recording layer type optical recording medium according to the present invention, a plurality of layers each including a recording layer to be initialized by light irradiation are formed on one surface side of a base material, and a space is provided between the respective layers. An apparatus for manufacturing a multilayer recording layer type optical recording medium for manufacturing a multilayer recording layer type optical recording medium having a recording layer, wherein a light transmittance with respect to an initialization laser beam is a recording laser beam and a reproduction laser beam. A spacer layer forming apparatus for forming the spacer layer having a lower light transmittance than that of the spacer layer; and the formed spacer layer. A layer forming apparatus for forming the layer thereon; and an initialization apparatus for irradiating the formed layer with the laser beam for initialization to initialize the layer.

In this case, the spacer layer forming apparatus has a light transmittance for the initialization laser beam of 70% or less, and a light for the recording laser beam and the reproducing laser beam. The spacer layer is preferably formed so that the transmittance is 80% or more. In addition, light having a wavelength of less than 500 nm is used as the recording laser beam and the reproducing laser beam, and the initialization apparatus uses the initialization laser beam as a beam having a wavelength of 500 nm or more. Further, it is preferable to use light having a wavelength of 100 nm or less, and the spacer layer forming apparatus is configured to form the spacer layer using a spacer layer material to which an infrared absorbing material is added. It is preferable that the layer forming apparatus forms the recording layer using a phase change material.

In such a method of manufacturing a multilayer recording layer type optical recording medium, the light transmittance for the laser beam for initialization is lower than the light transmittance for the laser beam for recording and the laser beam for reproduction. Forming a layer including a recording layer on the formed spacer layer, and irradiating the formed layer with a laser beam for initialization. By performing initialization, the initialization laser beam passing through this layer and further passing through the spacer layer can be sufficiently attenuated during this initialization. Of the laser beam for initialization reflected by the reflection layer of the laser beam for initialization can be avoided, and as a result, the layer including the recording layer can be uniformly initialized. Can be done. Also, when manufacturing a multilayer recording layer type optical recording medium having three or more recording layers, it is necessary to initialize a layer including a recording layer formed as a lower layer (a layer far from incident light) of the spacer layer. Initialization can be performed reliably and uniformly by directly irradiating an initialization laser beam prior to the formation of this spacer layer. Therefore, it is possible to manufacture a high-quality multilayer recording layer type optical recording medium in which the recording layers included in each layer are uniformly initialized. A multilayer recording layer type optical recording medium according to the present invention is manufactured by any one of the above-described methods for manufacturing a multilayer recording layer type optical recording medium. According to the multilayer recording layer type optical recording medium of the present invention, a plurality of layers each including a recording layer initialized by light irradiation are formed on one surface side of a base material, and a spacer is provided between the respective layers. A multilayer recording layer type optical recording medium having a layer formed thereon, wherein the spacer layer has a light transmittance for an initialization laser beam lower than a light transmittance for a recording laser beam and a reproduction laser beam. The rate is formed.

In this case, the spacer is so adjusted that the light transmittance for the initialization laser beam is 70% or less and the light transmittance for the recording laser beam and the reproduction laser beam is 80% or more. Preferably, a layer is formed. Further, light having a wavelength of less than 500 nm is used as the recording laser beam and the reproduction laser beam, and light having a wavelength of 500 nm or more and 100 nm or less is used as the initialization laser beam. It is preferably used. Further, it is preferable that the spacer layer is formed of a spacer layer material to which an infrared absorbing material is added. Further, it is preferable to form the recording layer with a phase change material. '' In this multilayer recording layer type optical recording medium, the spacer layer was formed so that the light transmittance for the initialization laser beam was lower than the light transmittance for the recording laser beam and the reproduction laser beam. When a multilayer recording layer type optical recording medium is manufactured, a layer including a recording layer is formed on the spacer layer, and the formed layer is initialized by irradiating a laser beam for initialization. In addition, since the initialization laser beam that passes through this layer and further passes through the spacer layer can be sufficiently attenuated, it is reflected by the reflective layer of the initialization laser beam that has passed through this layer. Thus, it is possible to avoid the initialization unevenness caused by the irradiation of the initialization laser beam, and as a result, it is possible to uniformly initialize the layer including the recording layer. Therefore, it is possible to sufficiently prevent the occurrence of an error during recording / reproducing by the recording / reproducing device used by the user. The present disclosure relates to the subject matter included in Japanese Patent Application No. 2001-1310, filed on October 15, 2000, which was filed on October 15, 2000. All of the disclosures are expressly incorporated herein by reference. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view showing a schematic configuration of a multilayer (two-layer) recording layer type optical recording medium 1 according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a configuration of the manufacturing apparatus 200 for the optical recording medium 1.

Fig. 3 shows the effect on the L0 layer caused by the irradiation of the laser beam LRE reflected by the L1 layer including the reflective layer 3 when initializing the optical recording medium 1 on which the L1 layer and the L0 layer were formed. It is an explanatory view for explaining.

Fig. 4 shows an optical recording medium 1 manufactured by variously changing the light transmittance of the spacer layer 5 in the optical recording medium 1, and the quality of initialization of the L0 layer in each optical recording medium 1 was tested. FIG. 9 is an explanatory diagram of experimental results showing experimental results at that time.

FIG. 5 is a cross-sectional view showing a schematic structure of a conventional single-layer recording layer type optical recording medium 21. FIG. 6 is a schematic view of a conventional multilayer (two-layer) recording layer type optical recording medium 31. FIG.

FIG. 7 is a graph showing the relationship between the laser beam LRE irradiated by the laser beam LRE reflected by the L1 layer including the reflective layer 3 when the conventional optical recording medium 11 having the L1 layer and the L0 layer formed thereon is initialized. It is explanatory drawing for demonstrating the influence on a layer. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, with reference to the accompanying drawings, a method for manufacturing a multilayer recording layer type optical recording medium according to the present invention, a manufacturing apparatus for a multilayer recording layer type optical recording medium, and a multilayer recording manufactured (by a manufacturing apparatus) according to the manufacturing method Description of preferred embodiments of layered optical recording medium I do. Note that components having the same structure as the optical recording media 21 and 31 described above are denoted by the same reference numerals, and redundant description will be omitted.

First, the configuration of a multilayer recording layer type optical recording medium (hereinafter, also referred to as “optical recording medium”) 1 in the present invention will be described with reference to FIG.

As shown in FIG. 1, the optical recording medium 1 has an L1 layer, a spacer layer 5, and an L layer adjacent to the spacer layer 5 on the side of the fine unevenness surface (the upper surface in FIG. 0 layers and a cover layer 7 are sequentially laminated.

In this case, the substrate 2 is formed into a disk shape having fine irregularities such as groups formed on the surface (one surface) thereof by injection molding using a resin material such as polycarbonate. As an example, the track pitch of the group formed on the base material 2 is set to 0.3 μm, and the depth of the group is set to the recording laser beam (laser beam set to the recording power) and the reproduction laser beam. (The laser beam set to the reproduction power) is set to about 1Z12. The reflective layer 3 is formed on the surface of the base material 2 on which fine irregularities are formed. The recording layer 4 has a first protective layer 4a, a phase change material layer 4b, and a second protective layer 4c, and these layers 4c, 4b, 4a are laminated on the reflective layer 3 in this order. It is configured. The spacer layer 5 is formed on the first protective layer 4a using a transparent resin material to which an infrared absorbing material is added. The spacer layer 5 has a thickness TH of usually about 20 μπι, and has fine irregularities (not shown) such as groups formed on one surface (the upper surface in the figure). . In this case, as the infrared absorbing material, for example, anthraquinone-based compounds, aluminum-based compounds, polymethine-based compounds, dimethyl-based compounds, and cyanine-based compounds are used. For this reason, in the spacer layer 5, the light transmittance for light having a wavelength of 500 nm or more and 100 nm or less is 0.1% or more due to the addition of such an infrared absorbing material. On the other hand, the light transmittance for light having a wavelength of less than 500 nm is not less than 80% and not more than 95%. Therefore, the spacer layer 5 is a recording and playback device used by the user. The optical transmittance of the recording laser beam and the reproducing laser beam (wavelength: 405 ηm; hereinafter, also referred to as “recording / reproducing laser beam” when no distinction is made) between the optical recording medium 1 and the optical recording medium 1 It has the characteristic that the light transmittance of the initializing laser beam (a laser beam having a wavelength of 810 nm and set to the initializing power) at the time is low.

Next, the manufacturing apparatus 200 for the optical recording medium 1 will be described with reference to FIG. The manufacturing apparatus 200 includes a reflective layer forming apparatus 101, a recording layer forming apparatus 102, an initializing apparatus 103, a spacer layer forming apparatus 201, and a recording layer forming apparatus (layer forming apparatus). 202, an initializing device 203, and a light transmitting layer forming device 104. In this case, the reflecting layer forming apparatus 101 includes a reflecting layer forming chamber 101a and a sputtering apparatus 101b disposed in the reflecting layer forming chamber 101a, and the reflecting layer forming chamber 101 It has a function of forming a reflective layer 3 on the surface of the substrate 2 carried into 1a by a sputtering device 101b. The recording layer forming apparatus 102 includes a recording layer forming chamber 102 a and a sputtering apparatus 102 b disposed in the recording layer forming chamber 102 a, and is provided in the recording layer forming chamber 102 a. It has a function of forming a recording layer 4 on the surface of the loaded base material 2 with a sputtering device 102b. The initialization device 103 includes a rotating mechanism 103 a for rotating the base material 2 and a laser beam for initialization along a group formed on the base material 2 driven by a tracking mechanism (not shown). A pickup 103 b for irradiating the substrate 2 with LIN; and a function of initializing the recording layer 4 formed on the surface of the substrate 2. The spacer layer forming apparatus 201 includes a rotating mechanism 201 a for rotating the base material 2, a dropping mechanism for the coating liquid R 1 (not shown), a transparent stamper 201 b, and an ultraviolet irradiation mechanism (see FIG. (Not shown), and a function of forming a spacer layer 5 as a light transmitting layer on the surface of the substrate 2 by spin coating. The recording layer forming apparatus 202 includes a recording layer forming chamber 202 a and a sputtering apparatus 202 b disposed in the recording layer forming chamber 202 a, and is provided in the recording layer forming chamber 202 a. It has a function of forming the recording layer 6 on the surface of the loaded base material 2 with a sputtering device 202b. The initializing device 203 includes a rotating mechanism 203 for rotating the substrate 2 and a rotating mechanism 203 a. A pickup 203 b that irradiates the substrate 2 with the initialization laser beam LIN along the group formed on the substrate 2 by being driven by a tracking mechanism (not shown), It has a function of initializing the formed recording layer 6. The light transmitting layer forming apparatus 104 includes a rotating mechanism 104 for rotating the substrate 2, a dropping mechanism 104 b for the coating liquid R, and an ultraviolet irradiation mechanism (not shown). In addition, it has a function of forming a power layer 7 as a light transmitting layer by a spin coating method. Next, a method for manufacturing the optical recording medium 1 will be described.

First, the base material 2 is formed into a disk shape having fine irregularities such as groups formed on its surface (one surface) by injection molding. Next, after the reflection layer 3 is formed on one surface side of the base material 2 by the reflection layer forming device 101, the recording layer 4 is formed on the reflection layer 3 by the recording layer forming device 102. At this time, the phase change material layer 4b is generally formed by a sputtering method.

Next, the formed L1 layer is irradiated with the initialization laser beam LIN by the initialization device 103 from the same direction as the irradiation direction of the recording / reproducing laser beam, and the L1 layer including the recording layer 4 is irradiated. Initialize the layer (specifically, the L1 layer including the phase change material layer 4b). Next, for example, the spacer layer 5 is formed on the L1 layer by performing the 2P method using the transparent stamper 201b with the spacer layer forming apparatus 201. In this case, a resin material (coating liquid R 1) to which an infrared absorbing material is added is dropped on the surface of the base material 2 on which the recording layer 4 is formed, and the resin material is thinly coated on the first protective layer 4 a by spin coating. After being applied in the form of a film, a transparent stamper 201b for forming a fine round protrusion such as a group is placed on the uncured applied resin material. After that, the resin material is cured by irradiating ultraviolet rays, and then the transparent stamper 201b is removed. At this time, fine irregularities are formed on the upper surface of the spacer layer 5 by the fine irregularities formed on the surface of the transparent stamper 201b. Next, the L0 layer is formed on the surface of the spacer layer 5 on which the fine irregularities are formed by the recording layer forming device 202. At this time, the phase change material layer 6b is formed by, for example, a sputtering method. Next, the formed LO layer is irradiated with the initialization laser beam LIN by the initialization device 203 from the same direction as the irradiation direction of the recording / reproducing laser beam, thereby initializing the L0 layer including the recording layer 6. I do. At this time, as shown in FIG. 3, part of the initialization laser beam LIN irradiated from the lens 11 to the L0 layer in the pickup 203b is partially replaced by the L0 layer and the L0 layer.通過 Pass the spacer layer 5 to reach the L1 layer. Then, a part of the laser beam LRE of the laser beam LPE that has reached the L1 layer is reflected by the L1 layer (particularly, the reflection layer 3 in the L1 layer) to irradiate the L0 layer. In this case, the light amount of the laser beam LRE that irradiates the L0 layer is the laser beam that has passed through the L0 layer because the wavelength of the initialization laser beam L IN (= 810 nm) is in the range of 500 nm to 1000 nm It is reduced to less than half (0.7 X 0.7 X (reflectance of L1 layer) ≤ 0.49) based on the light intensity of the beam LPE. For example, when the reflectance of the L1 layer with respect to the initialization laser beam LIN is 40%, (0.7X0.7.7X0.4 = 0.196), and the amount of the laser beam LRE is It is reduced to about 1/5 of the light intensity of the beam L IN.

Finally, the power-par layer 7 is formed on the initialized L0 layer using the light-transmitting layer forming apparatus 104, for example, by spin coating. Specifically, a resin material (coating liquid R) of a resin having optical transparency is dropped on the L0 layer of the base material 2 by the dropping mechanism 104b, and then, the rotating mechanism 104a is operated to operate the base material 2. Rotate (by spin coating) to apply the resin material in a thin film on the L0 layer, and then irradiate ultraviolet rays to cure the resin material. Thus, the manufacture of the optical recording medium 1 is completed.

As described above, according to the method of manufacturing the optical recording medium 1 and the manufacturing apparatus 200, the infrared ray absorbing material is added to the optical recording medium 1 to scan light of 500 nm or more and 1000 nm or less (initialization laser single beam L IN). By setting the light transmittance of the laser layer 5 to 70% or less, when the L0 layer is initialized, the amount of light from the laser beam LPE that passed through the L0 layer and reached the L1 layer was The light amount can be reduced to 70% or less. At the same time, the laser beam is reflected by the reflective layer 3 of the LPE and reaches the L0 layer. It is possible to reduce the light quantity of the one-beam-one LRE to 70% or less of the light quantity at the beginning of reflection. As a result, the light amount of the laser beam LRE, which irradiates the L0 layer from the base material 2 side, can be reduced to about half (about 49%) or less of the initial light amount of the laser beam LPE. +

In this case, the inventor changed the light transmittance of the spacer layer 5 variously by changing the type of the infrared absorbing material added to the spacer layer 5 or adjusting the addition ratio. The recording medium 1 was manufactured, and the quality of the initialization of the L0 layer for each optical recording medium 1 was tested. Figure 4 shows the experimental results at this time. According to the experimental results shown in the figure, when the light transmittance of the spacer layer 5 is set to Ί0% or less, the initialization state is determined to be good, and the light transmittance of the spacer layer 5 is reduced. 7 When it was set to 1% or more, the initialization state was determined to be defective. Therefore, as is clear from the experimental results, by setting the light transmittance of the spacer layer 5 to 70% or less, the laser beam reflected by the L1 layer and the laser beam irradiated to the L0 layer were set. It is possible to reliably avoid the occurrence of unevenness in the initialized state of the already initialized portion of the L0 layer caused by the above-described interference with the beam L IN. As a result, the L0 layer including the recording layer 6 can be initialized uniformly and well. On the other hand, when initialization is performed using a recording / reproducing device used by the user (a recording / reproducing laser beam with a wavelength of 405 nm is emitted from an objective lens with a numerical aperture of approximately 0.85). The light transmittance of the spacer layer 5 with respect to the recording / reproducing laser beam is secured to 80% or more. Therefore, even if the spacer layer 5 is present, it is possible to reliably initialize the L1 layer by irradiating the recording / reproducing laser beam only with an influence that does not hinder the initialization. In this case, since the recording / reproducing laser beam is normally radiated by using an objective lens having a large numerical aperture ΝΑ, the recording / reproducing laser beam reflected by the L1 layer and radiated to the L0 layer is irradiated. As a result, the unevenness in the initialization of the L 0 layer due to re-irradiation is reliably avoided.

The present invention is not limited to the above-described embodiment of the invention, and can be appropriately modified. . For example, in the embodiment of the present invention, the manufacturing method of initializing the L0 layer prior to the formation of the cover layer 7 has been described as an example, but the L0 layer is initialized after the cover layer 7 is formed. You may. When this manufacturing method is adopted, it is preferable to increase the light transmittance of the cover layer 7 with respect to the initialization laser beam LIN, so that the power-par layer 7 is added without adding an infrared absorbing material. Preferably, it is formed.

Further, in the embodiment of the present invention, an example in which the optical recording medium 1 of the two-layer recording layer type optical recording medium having the two recording layers 4 and 6 is described, but the formation of the spacer layer 5 and the recording By repeating the formation of the layer 6 and the initialization for the recording layer 6, a multilayer recording layer type optical recording medium having three or more recording layers and in which each recording layer is uniformly initialized can also be manufactured. The manufacturing apparatus in this case is configured by increasing the spacer layer forming apparatus 201, the recording layer forming apparatus 202, and the initializing apparatus 203 in the manufacturing apparatus 200 by the number of repetitions. . Industrial applicability

As described above, according to the method and apparatus for manufacturing the multilayer recording layer type optical recording medium, the light transmittance for the initialization laser beam is lower than the light transmittance for the recording laser beam and the reproduction laser beam. A spacer layer is formed so as to obtain a ratio, and a layer including a recording layer is formed on the formed spacer layer, and the formed layer is initialized by irradiating a laser beam for initialization. Thereby, at the time of this initialization, the initialization laser beam that passes through this layer and further passes through the spacer layer can be sufficiently attenuated. For this reason, it is possible to avoid the initialization unevenness due to the irradiation of the initialization laser beam reflected by the reflective layer in the initialization laser beam that has passed through this layer, and as a result, the recording layer Can be uniformly initialized. In the case of manufacturing a multilayer recording layer type optical recording medium having three or more recording layers, it is necessary to initialize a layer including a recording layer formed as a lower layer (a layer far from incident light) of the spacer layer. Before the formation of this spacer layer, Initialization can be performed reliably and uniformly by directly irradiating the laser beam for initialization. This realizes a method and apparatus for manufacturing a multilayer recording layer type optical recording medium capable of manufacturing a high quality multilayer recording layer type optical recording medium in which the recording layers included in the respective layers are uniformly initialized. .

Claims

The scope of the claims

1. A multilayer recording layer type optical recording medium in which a plurality of layers each including a recording layer initialized by light irradiation are formed on a surface side of a substrate and a spacer layer is formed between the respective layers. A manufacturing method,

The spacer layer is formed so that the light transmittance with respect to the initialization laser beam is lower than the light transmittance with respect to the recording laser beam and the reproduction laser beam, and the layer is formed on the formed spacer layer. Forming a layer, and irradiating the formed laser beam with the laser beam for initialization to initialize the multilayer recording layer type optical recording medium.

2. The light transmittance with respect to the initialization laser beam is 70% or less, and the light transmittance with respect to the recording laser beam and the reproduction laser beam.

2. The method for manufacturing a multilayer recording layer type optical recording medium according to claim 1, wherein the spacer layer is formed so as to have a concentration of 80% or more.

3. Light having a wavelength of less than 500 nm is used as the recording laser beam and the reproducing laser beam, and light having a wavelength of 500 nm or more and 100 nm or less is used as the initialization laser beam. 2. The method for producing a multilayer recording layer type optical recording medium according to claim 1, wherein the method is used.

4. Light having a wavelength of less than 500 nm is used as the recording laser beam and the reproducing laser beam, and light having a wavelength of 500 nm or more and 100 nm or less is used as the initialization laser beam. 3. The method for producing a multilayer recording layer type optical recording medium according to claim 2, which is used.

5. The method of manufacturing a multilayer recording layer type optical recording medium according to claim 1, wherein the spacer layer is formed of a spacer layer material to which an infrared absorbing material is added.

6. The method for producing a multilayer recording layer type optical recording medium according to claim 2, wherein the spacer layer is formed of a spacer layer material to which an infrared absorbing material is added.

7. The method for manufacturing a multilayer recording layer type optical recording medium according to claim 1, wherein the recording layer is formed of a phase change material.

8. The method for producing a multilayer recording layer type optical recording medium according to claim 2, wherein the recording layer is formed of a phase change material.

9. A multilayer recording layer type optical recording medium in which a plurality of layers each including a recording layer initialized by light irradiation are formed on the surface side of the base material and a spacer layer is formed between the respective layers. A manufacturing apparatus for manufacturing,

A spacer layer forming apparatus for forming the spacer layer having a light transmittance for the initialization laser beam lower than the light transmittance for the recording laser beam and the reproduction laser beam; A multi-layer recording layer type optical recording medium, comprising: a layer forming device for forming the layer on a semiconductor layer; and an initialization device for irradiating the formed layer with the initialization laser beam to initialize the layer. Manufacturing equipment.

10. The spacer layer forming apparatus, wherein the light transmittance for the initialization laser beam is 70% or less, and the light transmittance for the recording laser beam and the reproducing laser beam. 10. The apparatus for manufacturing a multilayer recording layer type optical recording medium according to claim 9, wherein the spacer layer is formed so as to be 80% or more.

11. The light having a wavelength of less than 500 nm is used as the recording laser beam and the reproduction laser beam, and the initialization device has a wavelength of 500 nm or more as the initialization laser beam. 10. The method according to claim 9, wherein light having a wavelength of 0 nm or less is used.

12. The multilayer recording layer type optical recording medium according to claim 9, wherein the spacer layer forming apparatus forms the spacer layer using a spacer layer material to which an infrared absorbing material is added.

13. The layer forming apparatus according to claim 9, wherein the recording layer is formed of a phase change material.

14. A multilayer recording layer type optical recording medium manufactured according to the method for manufacturing a multilayer recording layer type optical recording medium according to any one of claims 1 to 8.

15 5. Multiple layers including the recording layer initialized by light irradiation A multilayer recording layer type optical recording medium which is formed on one surface side and a spacer layer is formed between the respective layers,

The multilayer recording layer type optical recording medium, wherein the spacer layer is formed to have a light transmittance for an initialization laser beam lower than a light transmittance for a recording laser beam and a reproduction laser beam.

16. The spacer layer has a light transmittance of 70% or less with respect to the initialization laser beam, and has a light transmittance of 80% with respect to the recording laser beam and the reproduction laser beam. 16. The multilayer recording-layer type optical recording medium according to claim 15, wherein the optical recording medium is formed in an amount of at least 30%.

17. The laser beam for recording and the laser beam for reproduction have a wavelength of less than 500 nm, and the laser beam for initialization has a wavelength of 500 nm or more and 100 nm or less. 16. The multilayer recording layer type optical recording medium according to claim 15, wherein said light is used.

18. Light having a wavelength of less than 500 nm is used as the recording laser beam and the reproducing laser beam, and the wavelength is used as the initialization laser beam.

17. The multilayer recording layer type optical recording medium according to claim 16, wherein light having a wavelength of 500 nm or more and 100 nm or less is used.

19. The multilayer recording layer type optical recording medium according to claim 15, wherein the spacer layer is formed of a spacer layer material obtained by adding an infrared absorbing material.

20. The multilayer recording layer type optical recording medium according to claim 16, wherein the spacer layer is formed of a spacer layer material to which an infrared absorbing material is added.

21. The multilayer recording layer type optical recording medium according to claim 15, wherein the recording layer is formed of a phase change material.

22. The multilayer recording layer type optical recording medium according to claim 16, wherein the recording layer is formed of a phase change material.