TWI220986B - Method and apparatus for initializing multi-layered recording layer type optical recording medium - Google Patents

Abstract

A method for initializing a multi-layered recording layer type optical recording medium including a plurality of layers (L1, L0); each containing a recording layer to be initialized by irradiation of light, which layers are stacked in this order on one side of a substrate via a spacer layer (12) formed between the layers (L1, L0). Initialization of one layer (L0) among the plurality of layers (L0, L1) is performed by applying light from the layer (L0) side by using an object lens (31) having numerical aperture NA which satisfies an equation [TH*NA >= 9] wherein TH (mum) is thickness of a spacer layer (12) adjacent to the surface of the substrate (2) side in the layer (L0). Thus, it is possible to uniformly initialize the layers (L1, L0) containing the recording layers.

Description

1220986 __Case No. 91123318 ___ ^ Amendment on the day of the month, V. Description of the invention (1) " Technical field to which the invention belongs: The invention relates to a method of forming a plurality of layers including a recording layer formed on one surface of a substrate, and forming An initializing method and an initializing device for a multilayer recording layer optical recording medium with a spacer layer between the plurality of layers. Prior art: Optical recording media have attracted attention due to their advantages such as high density and large capacity, and they have been applied to a variety of applications. In particular, a rewriteable optical recording medium that can erase recorded information and perform re-recording, because it can carry out data

It can be repaired and updated, and can be read and written repeatedly, so it is particularly valued for the wide application of optical recording media. Among such optical recording media, magneto-optical Z recording media (M0) and phase change optical recording media have been developed and commercialized. Among them, in the phase-change type optical recording medium (hereinafter referred to as "optical recording medium") that can be repeatedly read and written by using phase change, the present inventors have developed an optical recording medium with a ^ layer poor structure. As shown in Figure 5. Optical recording medium η: One surface (upper surface in the figure) is formed by stacking a reflective layer 3, a recording layer 4, and a cover layer 5 as a light transmitting layer in order.

The material of the substrate 2 is a flat plate shape (for example, a disc shape) having a desired thickness by injection molding using a resin material such as polycarbonate. On the ^ surface (upper surface in the figure) of the substrate 2 are formed minute recesses (not shown) such as grooves for non-compliant servo. The reflective layer 3 is formed on the surface of the substrate 2 with fine unevenness using a metal such as A1 or Ag4Ni. The recording layer 4 includes a first dummy layer 4a, a phase-change material layer 4b, and a second protective layer 4c.

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1220986 Amendment No. 9112 ^ 1 «V. Description of the Invention (2) 4b and 4a are formed on the reflective layer 3 in this order. The material of the first protective layer and the second protective layer 4c is, for example, a dielectric material such as alumina or ZnS_SiO2, and the material of the phase change material layer 4b is, for example, GeTeSb, InSbTe, or AgGelnSbTe. The material of the cover layer 5 is, for example, A light-transmitting resin material is used to form the first protective layer 4a. In the optical recording medium 1, the recording layer 4 is irradiated with the recording laser beam set to the recording power from the cover layer 5 side. The recording layer 4 including the phase-change material layer 4b generates a reversible phase change between the amorphous state and the crystalline state, so that recording marks can be formed and removed. In other words, 'When the recording layer 4 is irradiated with a laser beam of recording power ( Especially when the phase-change material layer 4b), the irradiated part is heated to a temperature exceeding the melting point, and then rapidly cooled (quenched) to form an amorphous state, thereby forming a recording mark corresponding to the recording signal; when the laser beam of the recording power is irradiated When recording layer 4, the irradiated portion of recording layer 4 is heated to a temperature exceeding the crystallization temperature, and then slowly cooled (annealed) to form a crystalline state. When reading, when using a laser beam with a reading power (using a laser beam with a lower power than 1000 times) to irradiate, use the amorphous state ^ ,,,,. The difference of the light reflectance caused by the change of the optical constant is used to judge the presence or absence of 5 digits to read the data. When the optical recording medium 1 is produced, the surface of the optical recording medium 1 is first formed by injection molding with grooves. Subtle uneven disk-shaped substrate 2. Next, a reflective layer 3 is formed on the surface of the substrate 2, and then a recording layer 4 is formed on the reflective layer 3. At this time = the changing material layer 4b and the first and second protective layers 4a, 4c is generally sputtered / formed. Then, for example, a cover layer is formed on the recording layer 4 by using a spin coating method. Page 6 2186.255255.PFl (N) .ptc 1220986 _ tired number 91123318 5. Description of the invention (3) 5. Record The phase-change material layer 4b in layer 4 was amorphous η λ at the time of formation and cannot be recorded by the user. Therefore, the optical recording medium 1 is shipped in a state where the user can directly use it immediately. For media 1, the recording layer 4 (especially the phase change material layer The initial step is performed. Therefore, after the cover layer 5 is formed, the initialization step of the recording layer 4 needs to be performed. Therefore, the same direction as the radiating direction of the reading or recording laser beam (that is, from the cover layer 5 side) ), Using a high-power (initialization power) laser beam (hereinafter referred to as "initialization laser beam") to perform the initialization step of the recording layer 4. At this time, the laser beam for initialization is generally irradiated to an optical recording medium through an objective lens having a numerical aperture (NACmimericai aperture) of about 0.4 (for example, 0.34). Thus, the optical recording medium 1 having the initial recording layer 4 is completed. In order to meet the requirements of the development and commercialization of larger-capacity optical recording media, the inventor is currently engaged in optical recording media! Based on the development of optical recording media with greater capacity. About the description of this optical recording medium, please refer to FIG. 6. In the figure, parts having the same structure as the optical recording medium are marked with the same symbols, and descriptions thereof are not repeated. ^ This optical recording medium 11 is a single-sided multilayer (eg, two-layer) recording layer type optical recording medium (hereinafter referred to as a "multilayer recording layer type optical recording medium"), as shown in the figure, on one surface of the substrate 2 ( The upper surface in the figure) includes a reflective layer 3 and a recording layer, a spacer layer 12 as a light transmitting layer, a recording layer 14 (hereinafter referred to as "L0 layer"), and a light transmitting layer. The cover layer 5. The > thickness TH of the spacer layer 12 is usually set to 20, and fine irregularities such as grooves are formed on the surface of the L0 layer side. Recording layer 4 includes a first protective layer

2186-5255-PFl (N) .ptc Page 7 1220986-^ --- Case No. 91123318_Year Month Date You are five. Description of the invention (4) One _ -----

Ma, the phase change material layer 14b, and the second protective layer 14c. The above-mentioned layers "^^, 14b, and 14a are formed in this order on the surface of the spacer layer 2 with fine unevenness. Although each layer 14a, 14b, 14c The materials and thicknesses of the corresponding layers 4a, 4b, and 4c are different, but they have the same function. The material of the cover layer 5 is a resin material and is formed on the layer L0. 'Even for the optical recording medium 11, in During the manufacturing process, the recording and layer 4 and 14 initialization steps are still required. As shown in Fig. 7, it is the same as that of the optical recording medium. After the cover layer 5 is formed, it is the same as when the optical recording medium 1 is initialized. The objective lens 21 having the same numerical aperture NA is used to perform the initialization step. Specifically, the laser beam L for initialization is used to face ^ 1 layer from the cover layer 5 side and irradiated: to perform the initial process including the recording layer "L1 layer" · Initialize the L0 layer by irradiating the laser beam k for initialization to the L0 layer as shown in the figure. Thus, the optical recording medium 11 having the initialized L1 layer and the L0 layer is completed. ° The present inventors reviewed the initialization method of the above-mentioned multilayer recording layer optical recording medium 'and found that the following shortcomings are in urgent need of improvement. That is, as shown in FIG. 7, when the L0 layer formed on the spacer layer 12 is initialized in this initialization method, 'a part of the laser beam lpe of the initialization laser beam Lin used for irradiating the L0 layer is irradiated' It will pass through the L0 layer and the spacer layer 12 and the laser beam Lp, E = part of the laser beam LRE will be reflected by the L1 layer. At this time, the reflected laser beam LRE and the initialization laser beam lin used to irradiate the L0 layer may cause an interference phenomenon due to the uneven thickness of the layer 12. Therefore, the light 1 absorbed by the layer may be partially different, which results in different amounts of heat generation in each portion of the L0 layer (heat unevenness on the L0 layer). Therefore, due to the reflected laser beam

Page 8 1220986 Case No. 91123318 V. Description of the invention (5) After re-irradiation of LEe, the phase change material layer 14b in the layer L0, especially the recording layer 14 may produce an uneven crystalline state, which cannot be performed well. Initialization step, it is best to improve on this shortcoming. Initialization of a multi-layer recording layer type recording medium has a substrate formed on the substrate. SUMMARY OF THE INVENTION Therefore, in order to improve the above-mentioned lack of a multi-layer recording layer, the optical recording medium layers are uniformly initialized, and a multi-layer recording layer type Lu Ji is provided. The present invention provides a multilayer notation in which each layer of the recording layer is uniform. The multilayer recording layer type optical recording surface includes a plurality of recording layers L0 (N is an integer of 1 or more), and the recording layer is illuminated by light. The initialization method of the recording medium includes initializing the plurality of layers of light from the L 0 layer side to initialize, wherein the thickness of the spacer layer adjacent to the surface uses the numerical aperture NA and the above-mentioned objective lens of the above formula. · T X X NA — 〇 In addition, the present invention provides a multi-layer recording layer type optical recording device, the main purpose of the present invention is to provide an initialization method, which can include a recording step. Furthermore, the initialization device of another medium of the present invention may include an initialization step. The initial recording layer of the recording optical recording medium has a surface layer LN, L (N-1), ..., L2, L1 formed on one of the substrates, and a spacer layer formed between the plurality of layers. When using an objective lens with a numerical aperture NA, the middle layer LM (N 21) is irradiated with the laser. The surface of the layer LM on the substrate side is TH (// m). The relationship between the thickness and the thickness of the laser light satisfies the following equation.

Page 9 1220986 _Case No. 9123318_Year Month Day Amendment V. Description of Invention (6) The plural layers including recording layers LN, L (N-1), ..., L2, L1, L0 (N is An integer of 1 or more), and a spacer layer formed between the plurality of layers, wherein the recording layer is initialized by light irradiation, and the initialization device of the multilayer recording layer type medium includes: an objective lens having a numerical aperture NA, used by the L0 layer The layer LM (N-μ -1) of the plurality of layers is irradiated with laser light for initialization, wherein the thickness of the spacer layer adjacent to the surface of the layer LM on the substrate side is TH (when the above The relationship between the numerical aperture NA of the objective lens and the thickness TH described above will satisfy the following equation: τ X NA .9.

Initialization method and initialization device for optical recording medium of multilayer recording layer according to the present invention 'When performing the initialization step of a layer, if the thickness of the spacer layer adjacent to the surface of the layer on the substrate side is TH (V m) The objective lens with numerical aperture NA satisfying the formula (TΗ X NA -9) is initialized by irradiating laser light on the L0 layer side, so that the reflection reflected by the layer L (M + 1) adjacent to the spacer layer can be reduced. The effect of light, so the layer can be uniformly initialized. Therefore, an initialized multilayer recording layer type optical recording medium with high reliability can be manufactured.

The invention provides a method for initializing a multilayer recording layer optical recording medium. The above-mentioned multilayer recording layer type optical recording medium has a plurality of layers LN, [(Nd), ..., L2, each including a recording layer formed on one surface of a substrate. L0 (N is an integer of 1 or more), and a spacer layer formed between the plurality of layers, wherein the recording layer is initialized by light irradiation, and the initialization method of the present invention includes: using a numerical aperture ^ value of 0.55 or more The objective lens irradiates laser light from the L0 layer side to one of the plurality of layers, so that

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Case No. 91123318 V. Description of the invention (7) Initialization. Furthermore, the present invention provides an initial setting of a multilayer recording layer type medium. The above-mentioned multilayer recording layer type optical recording medium has a plurality of layers LN, [(N-〗), ... , L2 L0 (N is an integer of 1 or more), and formed between the plurality of layers, wherein the recording layer is initialized by light irradiation, and the above-mentioned multi-layer recording medium initialization device includes: an objective lens with a numerical hole # ΝΑ: In two, the L-0 layer side irradiates laser light on the layer LM (N ^ Md) of the plurality of layers, and the numerical aperture NA of the objective lens is above 0.55. The second stage of the initialization method of the optical recording medium of the multilayer recording layer and the objective lens above, the laser light is irradiated from the L0 layer side to initialize the light. Si: Si ?: reflection reflected by the adjacent layer separated by the spacer layer = two = ”__ Initialize the uniform sentence of the recording layer. Recording medium. &Amp; Hachiman reliability initialization of multilayer recording layer type optical implementation: Please refer to the attached diagram for the initialization method of the recording medium. The multi-layered recording layer optical recording media 1 and 1 of t month have a detailed description of π a _. At first glance, its description is not repeated. 1 1 knife and spoon are marked with the same sign. Please refer to sections 1 and 6. Figure, optical access, touch recording, recording medium 11 has multiple layers according to the present invention

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^ = Layer optical recording medium initialization method The recording layer that has been initialized is completed. ^ The surface of the substrate 2 with the slight unevenness (the upper surface in the figure) is sequentially formed with the L1 layer, the spacer layer 12, and the spacer layer 12 adjacent to each other. The 10 layers and the cover layer 5 are stacked. Next, the initialization device M of the optical recording medium 丨 丨 of the present invention will be explained 'Please refer to FIG. 2. The initialization device M includes a bearing motor MT, a read-write head PU, a bearing servo SPS, a transmission servo TRS, a focus tracking servo FTS, and a control device CNT. The bearing motor MT is controlled by the bearing servo SPS, which makes the optical recording medium 丨 丨 rotate at a constant line speed, which will be described later. The read-write head PU is composed of a laser light emitting end and a laser light receiving end that are integrated to control the laser driving source to drive the laser light through the control device CNT (both are not shown in the figure) toward the optical recording medium 11 A laser beam Lin set to an initialization power is emitted to the optical recording medium 1. In addition, the read-write head pu also includes an objective lens 31 and a beam splitter (not shown) for focusing the laser beam Lin on the L1 layer and the L0 layer of the optical recording medium 11. Specifically, the focus tracking servo FTS performs focus tracking control on the objective lens 31 so that the initialization laser beam LIN is focused on the L1 layer and the L0 layer of the optical recording medium 11. At this time, if the thickness of the spacer layer 12 in the optical recording medium 11 is TH (, the objective lens 31 is configured using a numerical aperture NA that satisfies the following equation (1). ΤΗ X NA ^ 9 ........ ......... As mentioned above, the thickness TH of the spacer layer 12 is generally set to 20 / zm, or at least 1 6. 5 // m or more. Therefore, if the thickness of the spacer layer 丨 2 is, for example, 1 6 · 5 // m, the numerical aperture of the objective lens 3 1 that can satisfy the above formula (丨) is used.

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2 is an objective lens of 0.55. If the thickness * i3 # m formed by the spacer layer 12 is used, an objective lens having a numerical aperture "0" that satisfies the above formula (1) is used. In addition, the read-write head PU is controlled by the transmission servo TRS, and it follows the optical recording medium The diameter direction moves repeatedly between the inner diameter side and the outer diameter side. The bearing servo SPS controlled by the control device CNT controls the rotation of the bearing motor MT, so that the linear speed of the optical recording medium 11 is maintained constant. The control device CNT is used to control the drive of read / write head ", bearing servo sps, transmission servo trs, and focus compliance servo FTS.

Next, the initialization method of the optical recording medium 1 will be described, please refer to FIG. 1. Since the manufacturing method of the optical recording medium except for the initialization step is made by the same manufacturing method as above, it will not be repeated here. First, the bearing servo sps is driven by the control device CNT to drive the bearing motor MT and the optical recording medium 丨 丨 is rotated at a constant linear speed. Next, the control device CNT controls the drive servo TRS to move the read / write head 初始化 to the initial starting position, and controls the focus tracking servo FTS to align the focus position of the objective lens 31 to the light § The L1 layer of the recorded medium 11 makes the objective lens 3丨 Positioning. After that, the control device CNT controls the drive servo TRS and the focus tracking servo FTS, so that the read-write head pu moves from the diameter side to the outer diameter side, and the layer 5 side enters the L 丨 layer.

The irradiation of the laser beam LIN is ordered to perform an initialization step including the L 丨 layer of the recording layer 4. Next, after the focal position of the objective lens 31 is controlled by the control device CNT to align the objective lens 31 and the objective lens 31 is positioned, the same method described above is used to irradiate the laser beam Lin for initialization to the layer O0 to perform the layer including the recording layer 14 The initialization step at this time 'as shown in Figure 1, and the use of numerical aperture n A is 0. 3 4 之

! 22〇986 Case No. 91123318 Amendment V. Description of the Invention (1) The objective lens is the same. The laser beam LPE, which is a part of the initialization laser beam LIN irradiated by the L0 layer, passes through the L0 layer and the interval. Layer 12 reaches L1. A part of the laser beam LPE up to the L1 layer is reflected by the L1 layer (especially the reflection layer 3 in the L1 layer) and irradiates the L 0 layer. At this time, because the numerical aperture NA of the objective lens 31 is larger than the numerical aperture NA of the objective lens 21, the beam diameter DI of the laser beam LRE irradiated to the 10th layer is much larger than the beam diameter DI when the objective lens 21 is used (such as the first and seventh examples). As shown). In other words, when the objective lens 31 is used, the laser beam LRE reflected by the L1 layer is sufficiently dispersed. Therefore, when the laser power of the initialization laser beam LIN is set to a constant value 'for initialization of the L0 layer, the irradiation amount of the laser beam LRE per unit area reflected by the L1 layer and irradiated to the L0 layer will be much smaller than The amount of irradiation of the laser beam LRE per unit area when the objective lens 21 is used. In this way, when the objective lens 31 is used for initialization, although the laser beam LRE reflected by the L1 layer and the laser beam LIN irradiating the L0 layer may interfere with each other due to the uneven thickness of the spacer layer 12 described above, The radiant energy of the light beam Lre has been dispersed and sufficiently reduced, so that the phenomenon that the amount of light absorbed by the L 丨 layer is not the same will not occur. Therefore, the problem of non-uniform crystallization caused by the laser beam Lre being irradiated to the portion of the L0 layer that has been initialized can be avoided, and the LO layer can be well initialized. When the inventors set the thickness TH of the spacer layer 2 to a constant value (20 // m) and used various objective lenses with different numerical apertures NA, it was confirmed whether the initialization of the L0 layer was good or not. The results of this experiment are listed in Figure 3. According to the experimental results shown in the figure, when an objective lens with a numerical aperture NA value of 0.45 or less is used for initialization, the initialization state is judged to be poor; and a numerical aperture is used.

Page 14 2186-5255-PFl (N) .ptc 1220986 Month Amendment Case No. 9112331 «V. Description of the Invention (11) When the objective lens above 0 Ϊ f0 · 55 is initialized, its initialization state is Gui. Therefore, as long as the numerical aperture M value of the objective lens is set to 055, 隹 —Xiao ^ can initialize the 10 layers including the recording layer 14 and the 1 ^ 1 layer including the recording layer 4. In addition, if the thickness 间隔 of the spacer layer 12 is at least j # m or more, the above formula ⑴ can be satisfied as long as the numerical aperture NA value is 0.55 or more and the private Γ L is used. For this reason, the optical recording medium 11 is performing = I: As long as an objective lens having a numerical aperture NA value of 0.55 or more is used, a good initialization step can be performed on the LI f and = layers. In this way, a multilayer recording layer type optical recording medium that is initialized with different guilt can be manufactured. In addition, if the right spacer layer 12 is formed to have a thin thickness of 13 mm, since the above formula (1) can be satisfied only when an objective lens with a numerical aperture NA value of 0.7 is used, it is necessary to use a numerical aperture NA value. For an objective lens of 0.7 or more, a good initialization step can be performed for the [丨 layer and the L0 layer. As mentioned above, according to this initialization method and initialization device, when using the objective lens 31 with a numerical aperture NA value of 0.55 to perform the initialization step of the L0 layer, it is possible to avoid being located under the L0 layer (the layer farther from the incident light) ) The u-layer reflects the initialization unevenness caused by the laser beam LIN for initialization. Therefore, having the reflective layer 3 formed on the surface of the substrate 2 and the irradiation direction of the laser beam lin for initialization is The optical recording medium n formed by the layer and the L0 layer above the reflective layer 3 when the initialization step is performed, since the L0 layer (especially the phase change material layer 4b) has a uniform crystalline state, it can be The L0 layer above the L1 layer is surely and well initialized. In addition, the present invention is not limited to the above-mentioned embodiment, and can be appropriately modified. For example, as shown in FIG. 4, the present invention is also applicable to including records 2186-5255-PFl (N) .ptc Page 15 1220986 Amended Fifth, the description of the invention (12) The layer is more than three layers (for example, including the [0 layer and the dagger layer of the recording layer, respectively, and including the recording layer Layer 2 of L2 ) Initialization steps of the 10 layer and the L1 layer in the formed optical recording medium ^. At this time, the optical recording medium 41 is formed by sequentially forming an L2 layer with a thickness of TH of the spacer layer 12 on the surface of the sense board 2. Expressed in% as "lower spacer layer 12"), L1 layer, spacer layer 12, which is almost the same structure as lower spacer layer 12, L0 layer and cover layer 5, are laminated, L2 layer and optical recording medium 1 The li layer has the same structure; the u layer is adjacent to the gate spacer layer 12, and its structure is almost the same as the L0 layer in the optical recording medium n. The ^ LO layer is adjacent to the spacer layer 12, and its structure is almost 11 layers. When the optical recording medium 41 is initialized, the relationship between the TH of the lower spacer layer 2 and the numerical aperture NA can satisfy the objective lens 51 of the above formula (1). After that, the L2 layer, the U layer, and the L0 layer were sequentially irradiated with the laser beam k for initialization, and the L2 layer including the recording layer 4, the! ^ Layer including the recording layer 14 and the L0 including the recording layer 1 4 were sequentially performed. Layer initialization steps. In addition, if the thickness TH of each spacer layer is at least 16 · 5 // m or more, the objective lens 51 uses an objective lens having a numerical aperture NA value of 0.55 or more that satisfies the above formula (1). According to this initialization method, as shown in Figure 4, when the ^ 1 layer is initialized, the beam diameter DI of the laser light \ Lre reflected by the L2 layer and irradiated to the li layer is increased, so the lightning can be sufficiently reduced. The radiation beam ^ is the unit of the layer = the product irradiation amount. Therefore, the layer (especially the phase-change material layer 14b in the ^ layer) can have a uniform crystalline state, and the Li layer above the L2 layer can be reliably and uniformly initialized. In addition, when the initialization step of the L0 layer is performed, the beam diameter DI of the laser beam LRE that is reflected by the L2 layer (especially the reflective layer 3 in the 12 layer) and irradiates to the L0 layer is much larger than when the initialization of the li layer is performed. Laser

2186-5255-PFl (N) .ptc Page 16 1220986 Case No. 91123318_Year 3 __ One is the fifth, the description of the invention (13) beam diameter, therefore, the laser beam LRE has completed the initialization part of the L0 layer The impact is lower than when the L1 layer is initialized. Therefore, the L0 layer can also be well initialized. Furthermore, when the initialization of the L 0 layer is performed, even if the laser beam LPE passing through a part of the L 0 layer is reflected by the 11 layers, if the thickness TH of each of the spacer layers 12 and 12 is the same, the above formula (1) can be satisfied. Therefore, the L0 layer can be well initialized without being affected by the laser beam LRE reflected by the L1 layer, and an initialized multilayer recording layer type optical recording medium with high reliability can be manufactured. Industrial Applicability: As described above, in the method for initializing the multilayer recording layer optical recording medium and the initialization device for the multilayer recording layer type medium of the present invention, when the initialization step of the layer L (M) and the layer L (M) are performed, When the thickness of the spacer layer adjacent to the surface on the substrate side is TH (// m), an objective lens with a numerical aperture NA satisfying the formula (ΤΗ X ΝΑ -9) is used, and laser light is irradiated from the L0 layer side for initialization. In this way, the influence of the reflected light reflected by the adjacent layer L (M + 1) separated from the spacer layer can be reduced, so that the layer LM can be uniformly initialized. Therefore, an initialized multilayer recording layer type optical recording medium with high reliability can be manufactured. Therefore, by using the initialization method and the initialization device of the multilayer recording layer optical recording medium of the present invention, each layer including the recording layer can be uniformly initialized.

2186-5255-PFl (N) .ptc Page 17 1220986 Case No. 91123318 Modification Brief Description of Drawings Figure 1 is an explanatory diagram of the initialization method when the optical recording medium 11 having the L1 layer and the L0 layer is initialized. Fig. 2 is an explanatory diagram of the initialization device M when the optical recording medium 11 having the L1 layer and the L0 layer is initialized. Fig. 3 is an explanatory diagram of the experimental results of the initialization of the L 0 layer when the objective lens with different numerical aperture NA is used for initialization. Fig. 4 is a diagram illustrating an initialization method when the optical recording medium 41 having the L2 layer and the L1 layer is initialized. FIG. 5 shows a structural section of the optical recording medium 1 forming a recording layer 4

Face view. Fig. 6 is a sectional view showing the structure of an optical recording medium 11 having an L1 layer and an L0 layer. Fig. 7 is an illustration of an initialization method currently used by the inventors when initializing an optical recording medium 11 having an L1 layer and an L0 layer. Explanation of symbols: 1, 1 1, 4 1 to optical recording medium; 2 to substrate; 3 to reflective layer; 4, 14 to recording layer; 4a, 14a to first protective layer; 4b, 14b to phase change material layer; 4c 14c ~ second protective layer; 5 ~ cover layer;

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Claims (1)

Sixth, the scope of patent application i — a kind of multi-layer recording layer type light type including the integer of 1 or more of the recording layer) The 5th recording layer uses the light body's initialization side to use the layer LM (N where the thickness of the upper spacer layer) The aperture NA is performed as described above: Layer recording layer optical recording medium initialization method, the above-mentioned multi-recording medium has a plurality of layers LN, L (N — υ, ..., L2, L1, L0 (N is, and is formed in sequence) formed on one surface of a substrate in sequence. In the spacer layer between the plurality of layers, the upper layer is irradiated for initialization. The multi-layer recording layer optical recording medium method includes an objective lens with a numerical aperture NA, and the plurality of 2 M-1 are irradiated with laser light from the lq layer side to perform Initialization, when the surface of the layer LM adjacent to the substrate side is TH (// m), the laser light uses the objective lens whose relationship between the numerical thickness and TH satisfies the following equation to obtain X NA-9. 2 · A method for initializing a multi-layer recording layer optical recording medium. The above-mentioned σ-recorded layer type optically-recorded medium has a plurality of layers LN, L (N_1), and a recording layer sequentially formed on one surface of a substrate, respectively. ..., L2, LI, LO (N is an integer of 1 or more), and a spacer layer formed between the plurality of layers, wherein the recording layer is initialized by light irradiation, and the multilayer recording layer optical recording medium initialization method package include: Using an objective lens having a numerical aperture NA of 0.55 or more, laser light is irradiated to the layer LM (N) of the plurality of layers from the L0 layer side to perform initialization. 3. An initialization device for a multi-layer recording layer type medium, the above-mentioned multi-layer recording layer type optical recording medium has sequentially 2186-5255-PFl (N) .ptc Page 20 1220986 _______ Case No. 91123318 __Year Month_g_ Amendment ____ Sixth, the scope of the patent application includes the multiple layers LN, L (N-1) of the recording layer ... .. L2, LI, L0 (N is an integer of 1 or more), and a spacer layer formed between the plurality of layers, wherein the recording layer is initialized by light irradiation, and the initial and initial device of the multilayer recording layer type medium includes: An objective lens having a numerical aperture NA is used to initialize the layer LM (N-M -1) of the plurality of layers from the above-mentioned L0 layer side by laser light, which is adjacent to the surface of the layer LM on the substrate side When the thickness of the spacer layer is TH (/ zm), the relationship between the numerical aperture NA of the objective lens and the thickness T 满足 will satisfy the following equation: ΤΗΝΑ -9. Initialization device for a multi-layer recording layer-type medium 4. -------------- The above-mentioned multi-layer recording layer-type optical recording medium has a recording layer formed on one surface of a substrate in order, respectively. LN, L (N-1) ..... L2, an integer on L1 ^), and a spacer layer formed between the plurality of layers, wherein the recording layer is initialized by light irradiation, and the multilayer recording The layer 'initialization device includes: an objective lens without a numerical aperture NA of the earth spiral body, which is used for initialization by irradiating laser light for several layers of LM (N-M -1) from the above 10 layers, The numerical aperture NA of the objective lens is above 55. ’