JP2010211896A - Method of determining optimal power of light to be radiated onto optical disc, optical disc device, optical disc and method of manufacturing the optical disc - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein the determination of optimal power value of light onto each recording layer of an optical disc, under a plurality of recording conditions, causes the information recording region to be narrowed. <P>SOLUTION: A method of determining the optimal power value of light to be radiated onto an optical disc includes a dividing step (S2) of virtually dividing a region, where recording layers of an optical disc having the recording layers on one side overlap with each other into a plurality of sections; a power determination step (S3) of determining the optimal power values of light onto each recording layer under respective recording conditions, by using the plurality of sections with respect to the recording conditions in a case of recording information on the recording layers by using a light. The dividing step (S2) virtually divides the region into the plurality of sections, such that the corresponding sections in the respective recording layers mutually overlap in the thickness direction of the optical disc. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical disc having a plurality of recording layers.

  Currently, various optical disks capable of recording digital information such as moving images and still images are commercially available. As digital versatile optical discs (DVDs), DVD-R, DVD-RW, DVD + R, DVD + RW, and DVD-RAM are commercially available, and Blu-ray Discs compatible with blue lasers include BD- R and BD-RE are commercially available.

  With the spread of the Internet, digital cameras, and the like, digital information recorded on optical discs has increased rapidly, and there is a demand for an increase in the storage capacity of optical discs. In order to meet the demand, an optical disc in which two recording layers are laminated on one side (hereinafter referred to as “single-sided dual-layer optical disc”) has been commercialized. In the following description, the lower recording layer of the single-sided dual-layer structure optical disc is referred to as a first recording layer, and the upper recording layer is referred to as a second recording layer. That is, the first recording layer is a recording layer far from the optical head, and the second recording layer is a recording layer near the optical head.

  When digital information is recorded on an optical disk using laser light, it is necessary to determine the optimum power value of the laser light prior to recording. By the way, when the optical disc is a single-sided dual-layer optical disc, when digital information is recorded on the second recording layer on the side close to the optical head, the second recording layer is chemically changed by irradiation with laser light, and the second recording layer is chemically changed. The transmittance of the laser beam in the two recording layers changes before and after the recording of digital information. The change affects the power of the laser beam when digital information is recorded on the first recording layer far from the optical head.

  Therefore, before digital information is recorded on the information recording area of the single-sided, dual-layer optical disk using laser light, the digital information is recorded on the first recording layer in a state where the digital information is recorded on the second recording layer. Determine the optimum power of the laser beam. Further, the optimum power of the laser beam is determined when digital information is recorded on each of the first recording layer and the second recording layer in a state where no digital information is recorded on the first recording layer and the second recording layer.

  Specifically, in the prior art, before recording digital information in the information recording area, as shown in FIG. A PCA (Power Calibration Area) 101 and a PCA 102 are set, and a ring-shaped PCA 103 is also set as a test area in the outer peripheral portion, and the optimum power is determined as shown below. That is, in the PCA 103 at the outer periphery, first, dummy data is recorded on the second recording layer, and the optimum laser beam is used when digital information is recorded on the first recording layer while the dummy data is recorded on the second recording layer. Determine power. Further, in the PCA 101 in the inner peripheral portion, the optimum power of the laser beam is determined when digital information is recorded on the first recording layer in a state where no digital information is recorded on the first recording layer or the second recording layer. . Similarly, in the PCA 102 in the inner peripheral portion, the optimum power of the laser beam when recording digital information on the second recording layer in a state where no digital information is recorded on the first recording layer and the second recording layer. Determine (for example, see Patent Document 1).

International Publication No. 2006/035721 JP 2008-192258 A

White paper Blu-ray Disc www.blu-raydisc.com 2006

  The storage capacity of the optical disk is required to be further increased in scale, and an optical disk in which three or more recording layers are laminated on one side (hereinafter referred to as “single-sided multilayer structure optical disk”) has been proposed. For a single-sided multilayer structure optical disc, digital information is recorded on each recording layer depending on whether or not digital information is recorded on each recording layer and conditions such as recording speed (hereinafter referred to as “recording conditions”). It is necessary to determine the optimum power.

  However, as the number of recording layers increases, the recording conditions also increase. Therefore, when the ring-shaped PCA is set for each recording condition and the optimum power for each recording condition is determined by the method described with reference to FIG. 12, the number of PCAs increases and the information recording area becomes narrow. Therefore, in this method, although the recording capacity is increased by increasing the recording layer, the information recording area is narrowed, so that the original purpose cannot be sufficiently achieved. The recording conditions include conditions for each linear velocity when recording digital information.

  The present invention provides a method for determining the optimum power of light applied to an optical disc and an optical disc apparatus, which determine the optimum power of light for each recording layer under each of a plurality of recording conditions without narrowing the information recording area. Objective. In addition, the present invention provides an optical disc that can easily determine the optimum power of light for each recording layer under each of a plurality of recording conditions without narrowing the information recording area, and a method for manufacturing such an optical disc. With the goal.

  In order to solve the above problems and achieve the above object, the method for determining the optimum power of light applied to an optical disc according to the present invention is such that each recording layer of each of the recording layers of an optical disc having a plurality of recording layers on one side A division step of virtually dividing an overlapping area in each layer into a plurality of sections, and an optimum power of light for each recording layer under each of a plurality of recording conditions when information is recorded on each recording layer using light And a power determining step for determining for each recording condition using a plurality of the sections, and in the dividing step, the sections corresponding to each other in each recording layer have overlapping portions in the thickness direction of the optical disc. The region is virtually divided into a plurality of sections.

  The optical disc apparatus of the present invention uses light for each recording layer of an optical disc having a plurality of recording layers on one side, and a light that virtually divides an overlapping area in each recording layer into a plurality of sections. A power determining unit that determines the optimum light power for each recording layer under each of a plurality of recording conditions when information is recorded on each recording layer, for each recording condition using the plurality of sections. The dividing unit virtually divides the region into a plurality of sections so that the sections corresponding to each other in each recording layer overlap each other in the thickness direction of the optical disc.

  The optical disc of the present invention comprises a disc having a hole in the center, and a plurality of recording layers having a hole in the center, laminated on one surface of the disc. An address indicating position information is assigned to each of the plurality of positions of the recording layer according to the distance from the reference position, and the first address assigned to the first position of the one recording layer And the second distance calculated from the second address assigned to the second position is a third position that overlaps the first position in the recording layer stacking direction of the other recording layers. This is equal to the second distance calculated from the assigned third address and the fourth address assigned to the fourth position overlapping the second position in the stacking direction.

  The optical disc of the present invention comprises a disc having a hole in the center, and a plurality of recording layers having a hole in the center, laminated on one surface of the disc. Each of the plurality of positions of the recording layer is assigned an address indicating position information according to the distance from the reference position, and each of the recording layers is located at a predetermined distance from the reference position of the outer peripheral portion. The mark has a mark at a portion to be stacked, and the marks are stacked so as to overlap.

  In the optical disc manufacturing method of the present invention, a hole is provided in the center, and an address indicating position information is assigned to each of a plurality of positions according to a distance from a reference position. A mark forming step for forming a mark at a position located at a predetermined distance from a reference position, and a plurality of recording layers on one surface of a disc having a hole in the center so that the marks overlap each other And laminating step.

  The present invention provides a method for determining the optimum power of light applied to an optical disc and an optical disc apparatus that determine the optimum power of light for each recording layer under each of a plurality of recording conditions without narrowing the information recording area. it can. In addition, the present invention provides an optical disc that can easily determine the optimum power of light for each recording layer under each of a plurality of recording conditions without narrowing the information recording area, and a method for manufacturing such an optical disc. Can do.

1 is a configuration diagram of an optical disc device according to Embodiment 1. FIG. 1 is a perspective view of an optical disc according to Embodiment 1. FIG. 2 is a surface view of the optical disc according to Embodiment 1. FIG. 4 is a flowchart showing each step of the operation of the optical disc device of the first embodiment. 6 is a diagram illustrating an example of a recording condition according to Embodiment 1. FIG. FIG. 10 is a diagram illustrating another example of recording conditions according to the first embodiment. FIG. 10 is a diagram for explaining a method of manufacturing the optical disc according to the second embodiment. 6 is a diagram showing an overview of an optical disk manufacturing apparatus according to Embodiment 2. FIG. FIG. 10 is a diagram for specifying marks formed on the outer peripheral portion of each recording layer of the optical disc of the second embodiment. FIG. 6 is an exploded perspective view of an optical disc according to a second embodiment. FIG. 10 is a diagram for explaining marks on the optical disc according to the second embodiment. It is a figure for demonstrating the method of determining the optimal power of the conventional light.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to drawings.

(Embodiment 1)
First, the configuration of the optical disc apparatus 100 according to the first embodiment will be described with reference to FIG.

  FIG. 1 is a configuration diagram of an optical disc apparatus 100 according to the first embodiment. An optical disc device 100 is a device for recording digital information on an optical disc A having a plurality of recording layers. As shown in FIG. 1, an optical processing unit 1, a condition acquisition unit 2, a dividing unit 3, an optimum power The determination unit 4 includes a memory 5, a data acquisition unit 6, and a recording control unit 7.

  The light processing unit 1 is a component that irradiates light to the optical disc A and detects reflected light from the optical disc A, and includes an optical head and the like.

  The condition acquisition unit 2 acquires the division condition and the recording condition from the optical disc A and stores them in the memory 5. The division condition is a condition for dividing an area to be described later, and includes information for specifying the area and information for specifying the number of divisions. The information for specifying the region is, for example, a region sandwiched between a first circle having a radius of the first length and a second circle having a radius of the second length longer than the first length. In some cases, the information specifies the first length and the second length. The recording condition is a recording condition specified according to whether or not digital information is recorded on each recording layer constituting the optical disc A, the linear velocity at the time of recording, and the like. For example, when the optical disc A is an optical disc having three recording layers on one side, the recording condition is that the digital information is recorded at the basic linear velocity at the bottom layer while the digital information is recorded only at the top layer. This is a condition for determining the optimum power of light irradiated by the light processing unit 1 during recording.

  The dividing unit 3 virtually divides an overlapping area in each recording layer into a plurality of sections for each recording layer constituting the optical disc A according to the dividing condition, and stores the position information of each section in the memory 5. When the dividing unit 3 virtually divides each recording layer area into a plurality of sections, the dividing section 3 virtually divides the areas into a plurality of sections so that the corresponding sections in each recording layer overlap in the thickness direction of the optical disc A. To divide. Here, the region in the first embodiment includes a first circle having a first length as a radius and a second length having a radius longer than the first length at the outer peripheral portion of each recording layer. The dividing unit 3 virtually divides the area into 24 sections in the circumferential direction. Regions and sections will be described later with reference to FIG.

  The optimum power determination unit 4 performs each of a plurality of recording conditions when digital information is recorded on each recording layer of the optical disc A using light according to the position information and recording conditions of each section obtained by the dividing unit 3. The optimum light power for each recording layer is determined for each recording condition using a plurality of sections, and the determined value is stored in the memory 5.

  The memory 5 holds various information. The data acquisition unit 6 acquires data recorded in the information recording area of each recording layer of the optical disc A from the outside of the optical disc apparatus 100. The recording control unit 7 causes the optical processing unit 1 to record the data acquired by the data acquisition unit 6 on each recording layer of the optical disc A according to the value of the optimum light power for each recording condition.

The optical disc A of Embodiment 1 is a recording medium on which digital information is recorded, and is laminated on one surface of a disc (substrate) having a hole in the center, and the disc (substrate). And a plurality of recording layers having a hole in the center. The optical disc A of Embodiment 1 will be further described with reference to FIGS. FIG. 2 is a perspective view of the optical disc A, and FIG. As shown in FIG. 2, the optical disc A of Embodiment 1 is an optical disc having three recording layers on one side. Hereinafter, the three recording layers are referred to as a first recording layer A1, a second recording layer A2, and a third recording layer A3 in order from the side closer to the substrate A0. Therefore, the recording layer on the front side is the third recording layer A3. Each recording layer is made of a phase change material such as GeSbT, an inorganic material such as SiO ₂ or Si and Cu, or an organic material such as a dye.

  As shown in FIG. 3, the optical disc A has an auxiliary information recording area called a burst cutting area (hereinafter referred to as “BCA”) 11 on the inner periphery of the first recording layer A1. In the BCA 11, unique information of the optical disc is recorded. The unique information is information for identifying the attribute of the optical disc, for example, the outer diameter of the disc, the system (BD or DVD), the number of recording layers, manufacturer information, and the like. Further, the unique information includes individual information that is different for each optical disc for the purpose of protecting the copyright. The unique information is recorded in a bar code shape in the circumferential direction. The unique information includes the above-described division condition and recording condition. The unique information includes error correction information, a header, and the like for reliably recognizing the optical disc. After the optical disc is completed, the unique information is recorded by a dedicated device using a high output laser called a BCA cutter or an initialization device. The BCA 11 is an area provided in the reference recording layer and is not limited to being provided in the first recording layer A1. The BCA 11 is provided in any one of the first recording layer A1, the second recording layer A2, and the third recording layer A3.

  Each of the plurality of positions of each recording layer is assigned an address indicating position information corresponding to the distance from the reference position, such as a pre-address recorded in the wobble of the groove. That is, the first distance calculated from the first address assigned to the first position of one recording layer and the second address assigned to the second position is the same as that of the other recording layer. From the third address assigned to the third position overlapping the first position in the thickness direction of the recording layer and the fourth address assigned to the fourth position overlapping the second position in the thickness direction. It is equal to the calculated second distance.

  Next, the operation of the optical disc apparatus 100 according to Embodiment 1 will be described with reference to FIG.

  FIG. 4 is a flowchart showing steps of the operation of the optical disc apparatus 100 according to the first embodiment. When trying to record digital information on the optical disc A, the optical disc apparatus 100 determines the optimum power of light for each recording layer under each of a plurality of recording conditions before recording.

  Therefore, before recording digital information on the optical disc A, the condition acquisition unit 2 specifies the disc type information (whether it is DVD or BD, etc.) from the BCA 11 of the optical disc A via the optical processing unit 1. Information), information for specifying the number of recording layers, and the like, and the division condition and the recording condition are acquired and stored in the memory 5 (S1).

  As described above, the division condition includes information on the area to be divided and information (division information) specifying how many sections are to be divided. The area divided in the first embodiment is the PCA 10 shown in FIG. That is, the area divided in the first embodiment is the PCA 10 as a ring-shaped test area on the outer periphery of the optical disc A. Further, the division information in the first embodiment is information for equally dividing the PCA 10 into 24 sections D1 to D24 in the circumferential direction. In that case, each section has an angular range of 15 degrees. Note that the position of the ring-shaped PCA 10 may be specified by a first radius for specifying the inner periphery thereof and a second radius for specifying the outer periphery thereof.

  In the first embodiment, it is assumed that 14 recording conditions are recorded in the BCA of the optical disc A as shown in FIG. One of the recording conditions will be described by taking the recording condition in section D1 as an example. In section D1, digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. With respect to the first recording layer A1 in the absence, the optimum recording power (hereinafter referred to as “optimal recording power”) of the laser beam output from the light processing unit 1 when recording is performed at the basic recording speed of 1 × speed. ) Is determined. “Determining the optimum recording power” means changing the power of the laser beam and recording a plurality of dummy signals on the target recording layer on a trial basis, the jitter, amplitude, This means that the combination of the modulation factor and asymmetry determines the power of the laser beam that is the best. In the following description, FIG. 4 is used again.

  The dividing unit 3 virtually divides the PCA 10 of each recording layer constituting the optical disc A into 24 sections in the circumferential direction according to the dividing conditions stored in the memory 5 as shown in FIG. The position information of each section is stored in the memory 5 (S2). When the dividing unit 3 virtually divides the PCA 10 of each recording layer into 24 sections, first, a specific part (specific code) of specific information recorded in the BCA 11 is transmitted via the optical processing unit 1. ) And an address assigned to each of a plurality of positions of each recording layer. The dividing unit 3 compares the specific code centered on the center of the optical disc A, the position corresponding to the detected address, and the rotational phase reference signal generated from the FG and PG of the spindle motor of the optical processing unit 1. Then, the relative position of the position corresponding to the detected address with respect to the specific code when the center of the optical disk A is the center is specified, whereby each of the recording layer sections D1 to D24 is the thickness of the optical disk A. The PCA 10 of each recording layer is virtually divided into 24 sections in the circumferential direction so as to overlap in the direction. The specific part of the unique information recorded in the BCA 11, that is, the specific code is, for example, a specific part of the barcode recorded in the BCA 11. In addition, a pre-address recorded in the wobble of the groove can be used as an address assigned to each of a plurality of positions of each recording layer of the optical disc A.

  The optimum power determination unit 4 has a plurality of recording conditions when recording digital information on each recording layer of the optical disc A using a laser beam according to the position information and recording conditions of each section stored in the memory 5. The optimum power of light for each recording layer is determined for each recording condition using a plurality of sections, and the determined value is stored in the memory 5 (S3).

  The operation of the optimum power determination unit 4 will be specifically described with reference to FIG. The optimum power determination unit 4 records digital information in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3 according to the recording conditions shown in FIG. The optimum recording power of the laser beam output from the optical processing unit 1 when the recording is performed at the 1 × speed that is the basic recording speed is determined for the first recording layer A1 in the unrecorded state.

  In the section D2, the optimum power determination unit 4 performs the basic operation for the second recording layer A2 in a state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. The optimum recording power of the laser beam output from the light processing unit 1 when recording at the 1 × speed, which is a typical recording speed, is determined.

  In the section D3, the optimum power determination unit 4 performs the basic operation on the third recording layer A3 in a state where no digital information is recorded on any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. The optimum recording power of the laser beam output from the light processing unit 1 when recording at the 1 × speed, which is a typical recording speed, is determined.

  In section D4, the optimum power determination unit 4 determines the optimum recording determined in section D2 in a state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. A dummy signal is recorded on the second recording layer A2 at 1 × speed by the power, and then the optimum recording power of the laser beam when recording at 1 × speed is determined for the first recording layer A1 in that state. That is, in section D4, the optimum power determination unit 4 uses the optimum recording power of the laser beam when recording is performed at 1 × speed on the first recording layer A1 in the state where the dummy signal is recorded only on the second recording layer A2. To decide.

  In section D5, the optimum power determination unit 4 determines the optimum recording determined in section D3 in a state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. A dummy signal is recorded on the third recording layer A3 at 1 × speed by the power, and then the optimum recording power of the laser beam when recording at 1 × speed is determined for the first recording layer A1 in that state. That is, in the section D5, the optimum power determination unit 4 uses the optimum recording power of the laser beam when recording is performed at 1 × speed on the first recording layer A1 in the state where the dummy signal is recorded only on the third recording layer A3. To decide.

  In section D6, the optimum power determination unit 4 determines the optimum recording determined in section D2 in a state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. A dummy signal is recorded in the second recording layer A2 at 1 × speed by power, and a dummy signal is recorded in the third recording layer A3 at 1 × speed by the optimum recording power determined in the section D3, and then the first signal in that state is recorded. For the recording layer A1, the optimum recording power of the laser beam when recording at 1 × speed is determined. That is, in the section D6, the optimum power determination unit 4 performs laser recording at 1 × speed on the first recording layer A1 in a state where dummy signals are recorded on the second recording layer A2 and the third recording layer A3. Determine the optimum recording power of light.

  In section D7, the optimum power determination unit 4 determines the optimum recording determined in section D3 in a state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. A dummy signal is recorded on the third recording layer A3 at 1 × speed by the power, and then the optimum recording power of the laser beam when recording at 1 × speed is determined for the second recording layer A2 in that state. That is, in the section D7, the optimum power determination unit 4 uses the optimum recording power of the laser beam when recording is performed at 1 × speed on the second recording layer A2 in a state where a dummy signal is recorded only on the third recording layer A3. To decide.

  In section D8, the optimum power determination unit 4 performs the basic operation on the first recording layer A1 in a state where no digital information is recorded on any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. The optimum recording power of the laser beam output from the light processing unit 1 when recording at twice the typical recording speed is determined.

  In section D9, the optimum power determination unit 4 performs the basic operation for the second recording layer A2 in the state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. The optimum recording power of the laser beam output from the light processing unit 1 when recording at twice the typical recording speed is determined.

  In section D10, the optimum power determination unit 4 performs the basic operation for the third recording layer A3 in a state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. The optimum recording power of the laser beam output from the light processing unit 1 when recording at twice the typical recording speed is determined.

  In section D11, the optimum power determination unit 4 performs the optimum recording determined in section D2 in a state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. A dummy signal is recorded on the second recording layer A2 at 1 × speed by the power, or a dummy signal is recorded on the second recording layer A2 at 2 × speed by the optimum recording power determined in the section D9, and then the second signal in that state is recorded. For one recording layer A1, the optimum recording power of the laser beam when recording at double speed is determined. That is, in the section D11, the optimum power determination unit 4 uses the optimum recording power of the laser beam when performing the recording at the double speed on the first recording layer A1 in the state where the dummy signal is recorded only on the second recording layer A2. To decide.

  In section D12, the optimum power determination unit 4 determines the optimum recording determined in section D3 in a state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. A dummy signal is recorded at a 1 × speed in the third recording layer A3 by power, or a dummy signal is recorded at a 2 × speed in the third recording layer A3 by the optimum recording power determined in the section D10, and then the second signal in that state is recorded. For one recording layer A1, the optimum recording power of the laser beam when recording at double speed is determined. That is, in section D12, the optimum power determination unit 4 uses the optimum recording power of the laser beam when recording is performed at double speed on the first recording layer A1 in a state where a dummy signal is recorded only on the third recording layer A3. To decide.

  In section D13, the optimum power determination unit 4 sets a dummy in the second recording layer A2 in a state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. And a dummy signal is recorded on the third recording layer A3, and then the optimum recording power of the laser beam when the recording is performed at the double speed for the first recording layer A1 in that state is determined. That is, in section D13, the optimum power determination unit 4 performs laser recording at a double speed on the first recording layer A1 in a state where dummy signals are recorded on the second recording layer A2 and the third recording layer A3. Determine the optimum recording power of light. The recording of the dummy signal on the second recording layer A2 may be performed at 1 × speed with the optimum recording power determined in the section D2, or may be performed at 2 × speed with the optimum recording power determined in the section D9. .

  In section D14, the optimum power determination unit 4 determines the optimum recording determined in section D3 in a state where no digital information is recorded in any of the first recording layer A1, the second recording layer A2, and the third recording layer A3. A dummy signal is recorded at a 1 × speed in the third recording layer A3 by power, or a dummy signal is recorded at a 2 × speed in the third recording layer A3 by the optimum recording power determined in the section D10, and then the second signal in that state is recorded. For the two recording layers A2, the optimum recording power of the laser beam when recording at double speed is determined. That is, in the section D14, the optimum power determination unit 4 uses the optimum recording power of the laser beam when recording at the double speed for the second recording layer A2 in a state where the dummy signal is recorded only on the third recording layer A3. To decide. In the following description, FIG. 4 is used again.

  The data acquisition unit 6 acquires data recorded on the optical disc A (S4), and the recording control unit 7 performs data acquisition according to the optimum light power value for each recording condition stored in the memory 5. The data acquired by the above is recorded on each recording layer of the optical disc A by the optical processing unit 1 (S5). Thereby, digital information is recorded on each recording layer by laser light having an optimum power for each recording condition.

  As described above, the optical disc apparatus 100 according to the first embodiment virtually divides the overlapping area (PCA10) in each recording layer into a plurality of sections for each recording layer of the optical disc A. The optimum light power for each recording layer is determined for each recording condition using a plurality of sections. Since the overlapping area (PCA10) in each recording layer is used as a test area, digital information can be recorded on each recording layer with light of optimum power under each recording condition without narrowing the information recording area of the optical disc A.

  Further, since the ring-shaped area (PCA 10) divided by the dividing section 3 is provided in the outer peripheral portion of the optical disc A, in order to determine the optimum power of the laser light as compared with the case where the area is provided in the inner peripheral portion. Thus, the optimum power determination unit 4 can determine the optimum power with high accuracy.

  In the first embodiment, the region divided by the dividing unit 3 has been described as a ring-shaped region, but the region may be arc-shaped. The shape of the region is not limited.

  In the first embodiment, the dividing unit 3 includes the position of the specific part (specific code) of the unique information recorded in the BCA 11 and the address assigned to each of the plurality of positions of each recording layer. Is used to virtually equally divide the PCA 10 of each recording layer into 24 sections in the circumferential direction. However, the dividing unit 3 uses one position of any recording layer as a reference, and uses an address assigned to that position and an address assigned to each of a plurality of positions of each recording layer. The PCA 10 of each recording layer may be virtually equally divided into a plurality of sections in the circumferential direction. Alternatively, the optical processing unit 1 records a reference code in any recording layer, and the dividing unit 3 uses the position of the code and the address assigned to each of a plurality of positions in each recording layer. Then, the PCA 10 of each recording layer may be virtually equally divided into a plurality of sections in the circumferential direction.

  Further, the division condition and the recording condition may not be recorded on the optical disc A but may be stored in advance in the memory 5.

  Further, the recording condition is not limited to the recording condition shown in FIG. 5, but may be the recording condition shown in FIG. In short, the recording condition may be a condition that specifies a situation for determining the optimum power of the laser beam. The recording conditions shown in FIG. 6 will not be described in detail, but are used in the same manner as in FIG. That is, in the section D12, the optimum power determination unit 4 performs laser recording at a quadruple speed on the first recording layer A1 in a state where dummy signals are recorded on the second recording layer A2 and the third recording layer A3. Determine the optimum recording power of light. “4 × speed” and “8 × speed” in FIG. 6 mean that the recording speed is the reference 4 × speed and 8 × speed, respectively. Even in the same one rotation, the inner circumference cycle is short and the outer circumference cycle is long. For this reason, in consideration of the limit of the breaking strength of the polycarbonate substrate constituting the optical disc A, digital information is recorded at 4 × speed on the inner periphery and 8 × speed on the outer periphery. Therefore, it is important to determine the optimum power of the laser beam at various linear velocities. In the recording conditions of FIG. 6, for example, as in section D1, “1 × speed” is written in the column of the first recording layer A1, “1 × speed” is written in the column of the second recording layer A2, and the second When “1 × speed” is written in the column of the recording layer A2, the optimum power determining unit 4 determines the laser beam in each layer in order from the first recording layer A1 that is the lowest layer to the third recording layer A3 that is the uppermost layer. Determine the optimal power.

  In the first embodiment described above, the optical disc A has three recording layers, but the recording layer of the optical disc A is not limited to three.

  Further, the addresses assigned to each of the plurality of positions of each recording layer of the optical disc A used by the dividing unit 3 are addresses determined according to the distance from the reference position, and indicate position information. The pre-address recorded in the groove wobble can be used. However, the dividing unit 3 distributes ADIP (ADress in Pre-groove) units (for example, a length of about 0.3 mm in BD) assigned at intervals shorter than the pre-address to a plurality of recording layers. It may be used as an address assigned to each position. Similarly, the dividing unit 3 may use an address specified by an address assigned at a shorter interval than the ADIP unit as an address assigned to each of a plurality of positions in each recording layer.

(Embodiment 2)
Hereinafter, a method of manufacturing the optical disk according to the second embodiment will be described with reference to FIG.

  FIG. 7 is a diagram for explaining the method of manufacturing the optical disc according to the second embodiment. The optical disc manufactured by the manufacturing method according to the second embodiment is an optical disc that can easily perform the virtual division performed on the division target area by the division unit 3 according to the first embodiment.

  First, a disc-shaped glass substrate having a diameter of 200 mm and a thickness of 5 mm is precisely polished using cerium oxide, then the substrate is cleaned by brush cleaning and ultrasonic cleaning in ultrapure water, and then dried. As shown in FIG. 7A, a glass master 71 is prepared.

  Next, the glass master 71 is left in the saturated vapor of the adhesion agent hexamethyldisilazane (HMDS) to adhere the adhesion agent, and the photoresist is diluted with ethyl cellosolve acetate (ECA), and is then grown to 25 nm using a spinner. Then, it is baked at 80 ° C. to obtain a blank master 73 in which a photoresist 72 is provided on a glass master 71 as shown in FIG. 7B.

  Next, as shown in FIG. 7C, the surface of the blank master 73 is exposed with a laser beam 81 at a predetermined interval. Next, the blank master 73 is developed with an aqueous 0.2 N sodium hydrogen phosphate solution to form a guide groove 74 having a spiral wobble pre-address as shown in FIG. The guide groove 74 is formed to form a mark serving as a reference when the recording layers are stacked.

  For example, by using the apparatus shown in FIG. 8, the surface of the blank master 73 is exposed with a laser beam 81 at a predetermined interval. FIG. 8 is a diagram showing an overview of the optical disk manufacturing apparatus according to the second embodiment. An optical disk manufacturing apparatus includes a pre-address generator 91, a Wolve converter 92, a phase comparator 93, a SW 94, a laser light source 95, an electro-optic polarizer 96, an optical modulator 97, and a servo system 98. , A blank master 99, a spindle pulse device 111, and a feed system 112 including a spindle motor. First, the blank master 99 is rotated at a constant linear speed by a spindle motor, and a laser beam having a wavelength of 266 nm is irradiated onto the blank master 99 by the servo system 98 while applying focus servo. An electro-optic polarizer 96 is inserted in the middle of the optical path, and a latent image with a track pitch of 0.32 μm is fed from a radius of 21 mm in the feed system 112 into a guide groove having pre-address information by wobble with an amplitude of about 20 nm. Form continuously in a spiral up to 58.5 mm. Thereafter, the pre-address by wobble up to a radius of 61 mm as the phase mark, for example, address 195AB0 (h) in the outer peripheral area of the first recording layer, address 26A550 (h) in the second recording layer, or 595AB0 ( h) The address etc. is compared with the spindle pulse obtained from the phase of the spindle motor, and the optical modulator 97 is used at a specific angle position, about 1.0 mm for 1 degree, preferably about 0 for 0.5 degree. Only a 0.5 mm partial latent image with a track pitch of 1 μm is formed. Note that the phase mark may be provided at a plurality of two or more places instead of one place on the circumference.

  Next, a conductive film (not shown) such as nickel is formed on the photoresist 72 by sputtering or the like, and nickel is plated to a predetermined thickness using the conductive film as an electrode. ), A nickel layer 75 is formed on the photoresist 72. As a result, a reverse pattern of the uneven pattern of the photoresist is copied onto the nickel layer 75.

  Next, as shown in FIG. 7F, the nickel layer 75 is peeled from the glass master 71, the resist 72 is removed, and a master stamper 76 is formed.

  Thereafter, the oxide film on the surface of the master stamper 76 is peeled off by oxygen ashing, and a mother stamper 77 is formed as shown in FIG. 7G in order to transfer the shape opposite to the surface shape of the master stamper 76. Nickel plating is performed again, and then polishing is performed to smooth the back surface. Then, the mother stamper 77 is completed by punching the center portion and the outer peripheral portion (not shown) with reference to the transferred guide groove.

  Thereafter, the mother stamper 77 is set in a mold (not shown), and a polycarbonate resin is filled in the mold by an injection molding method, and then the mold is cooled by cooling water to form a polycarbonate in the mold. The resin is cured. Then, the polycarbonate resin layer is peeled off from the mold, and a guide groove 74 having a helical wobble pre-address is transferred to the polycarbonate resin layer to form a thickness of 1.1 mm as shown in FIG. An optical disk substrate 78 having a diameter of 120 mm (radius 60 mm) is formed.

Thereafter, a reflection film made of an Ag-based alloy having a thickness of 80 nm and a GeSbTe recording film having a thickness of 12 nm are formed on the optical disk substrate 78 as a first recording layer, and a ZnS—SiO ₂ protective film is formed on the recording film by sputtering over and under the recording film Form. The recording film can also be formed by applying a dye by spin coating. When forming the first recording layer, a mark is formed on the outer periphery by the guide groove 74 of the optical disk substrate 78.

  For the recording layers other than the first recording layer, an ultraviolet curable resin having a viscosity of 100 mPa · s is applied on each recording layer by spin coating in a thickness range of 10 to 25 μm, pressed against the mother stamper 77, and spirally wobbled. The guide groove having the pre-address is transferred and cured with ultraviolet rays or the like to form a reflective film, a recording film, a protective film, and the like. Thereby, a mark 85 is formed on the outer peripheral portion of the recording layer as shown in FIG. When forming a mark on the outer periphery of the recording layer, the center of the mother stamper 77 and the center of each recording layer are aligned by visual observation or an optical sensor.

  Then, as shown in FIG. 10, each recording layer is laminated so that the mark 85 formed on the outer periphery overlaps, and 2P resin is applied by spin coating for the purpose of forming a light-transmitting cover layer. An optical disc having a plurality of recording layers is produced by curing. FIG. 10 is an exploded perspective view of an optical disc formed of a polycarbonate substrate 88, a first recording layer 88A, a second recording layer 88B, and a third recording layer 88C.

  Since each recording layer is formed by using the mother stamper 77, addresses assigned to the same distance from the reference position of each recording layer are equal. As a result, since the optical disk manufactured by the manufacturing method according to the second embodiment is an optical disk in which the layers are stacked with reference to the mark, the addresses of the recording layers assigned to the positions overlapping each other in the thickness direction are equal. Therefore, the dividing unit 3 according to the first embodiment can easily divide the PCA 10 virtually by using the optical disk manufactured in the second embodiment.

  The surface opposite to the recording surface of the optical disc is printed with a label or the like for identification of the recording medium or differentiation by design. A general method for manufacturing a dual-layer disc is described in Non-Patent Document 2.

  Further, the mark formed on each recording layer may have any shape as shown in FIGS. 11 (A) to 11 (D). The mark is formed deeper than the groove in the information recording area of the recording layer. For example, the mark shown in FIG. 11 is formed by a groove having a depth of 10 nm to 100 nm, and is formed in an area having a radius of 58.5 mm to 61 mm which is a digital information recording area and an outer peripheral area of the PCA 10. The visibility can be improved by forming the mark in this way.

  DESCRIPTION OF SYMBOLS 100 Optical disk apparatus, 1 Optical processing part 1, 2 Condition acquisition part, 3 Dividing part, 4 Optimal power determination part, 5 Memory, 6 Data acquisition part, 7 Recording control part

Claims (11)

For each recording layer of the optical disc having a plurality of recording layers on one side, a division step of virtually dividing the overlapping area in each recording layer into a plurality of sections;
A power determination step for determining an optimum light power for each recording layer under each of a plurality of recording conditions when information is recorded on each recording layer using light for each recording condition using the plurality of sections. Including
In the dividing step, the region is virtually divided into a plurality of sections so that the sections corresponding to each other in each recording layer overlap in the thickness direction of the optical disk. Method. The region is a region sandwiched between a first arc having a radius of the first length of each recording layer and a second arc having a radius of the second length longer than the first length. ,
The method for determining the optimum power of light applied to the optical disc according to claim 1, wherein in the dividing step, the region is virtually divided into a plurality of sections in a circumferential direction. The optical disc has unique information recorded by a code in any of the plurality of recording layers,
Each of the plurality of positions of each recording layer is assigned an address indicating position information according to a distance from a reference position,
In the division step, each of the recording layers has an overlapping portion in the thickness direction using the code and an address assigned to each position of the recording layer so that the sections corresponding to each other overlap in the thickness direction. The method for determining the optimum power of light applied to the optical disc according to claim 1, wherein the region of the recording layer is virtually divided into a plurality of sections. Each of the plurality of positions of each recording layer is assigned an address indicating position information according to a distance from a reference position,
In the dividing step, using the address assigned to one position of any one of the recording layers and the address assigned to each position of each recording layer, the sections corresponding to each other in each recording layer The method for determining the optimum power of light applied to the optical disc according to claim 1, wherein the region of each recording layer is virtually divided into a plurality of sections so that each has an overlapping portion in the thickness direction. Furthermore, a code recording step of recording a code serving as a reference when virtually dividing the area of each recording layer into a plurality of sections on any of the plurality of recording layers of the optical disc,
Each of the plurality of positions of each recording layer is assigned an address indicating position information according to a distance from a reference position,
In the division step, each of the recording layers has an overlapping portion in the thickness direction using the code and an address assigned to each position of the recording layer so that the sections corresponding to each other overlap in the thickness direction. The method for determining the optimum power of light applied to the optical disc according to claim 1, wherein the region of the recording layer is virtually divided into a plurality of sections. For each of the recording layers of the optical disc having a plurality of recording layers on one side, a dividing unit that virtually divides a region overlapping each other in each recording layer into a plurality of sections;
A power determination unit that determines the optimum light power for each recording layer under each of a plurality of recording conditions when information is recorded on each recording layer using light for each recording condition using the plurality of sections And
The optical disc apparatus virtually divides the region into a plurality of sections so that the sections corresponding to each other in each recording layer overlap each other in the thickness direction of the optical disc. A disc with a hole in the center;
A plurality of recording layers laminated on one surface of the disc and having a hole in the center,
Each of the plurality of positions of each recording layer is assigned an address indicating position information according to a distance from a reference position,
The first distance calculated from the first address assigned to the first position of one of the recording layers and the second address assigned to the second position of the other recording layer is A third address assigned to a third position overlapping with the first position in the stacking direction of the recording layer and a fourth address assigned to a fourth position overlapping with the second position in the stacking direction. An optical disc equal to the second distance calculated from the address of the optical disc. A disc with a hole in the center;
A plurality of recording layers laminated on one surface of the disc and having a hole in the center,
Each of the plurality of positions of each recording layer is assigned an address indicating position information according to a distance from a reference position,
Each of the recording layers has a mark at a position located at a predetermined distance from the reference position on the outer peripheral portion, and is laminated so that the mark overlaps. The optical disk according to claim 8, wherein the mark is a groove deeper than a groove in an information recording area of the recording layer. Positioned at a predetermined distance from the reference position on the outer peripheral portion of the recording layer in which a hole is provided in the center and an address indicating position information is assigned to each of a plurality of positions according to the distance from the reference position A mark forming step for forming a mark on the part to be performed;
A stacking step of stacking a plurality of the recording layers on one surface of a disk having a hole in the center so that the marks overlap with each other. The optical disc manufacturing method according to claim 10, wherein in the mark forming step, a groove deeper than a groove in an information recording area of the recording layer is formed as the mark.

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