WO2010067555A1 - 情報記録媒体、再生装置および再生方法 - Google Patents
情報記録媒体、再生装置および再生方法 Download PDFInfo
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- WO2010067555A1 WO2010067555A1 PCT/JP2009/006607 JP2009006607W WO2010067555A1 WO 2010067555 A1 WO2010067555 A1 WO 2010067555A1 JP 2009006607 W JP2009006607 W JP 2009006607W WO 2010067555 A1 WO2010067555 A1 WO 2010067555A1
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- information recording
- recording layer
- layer
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- reproducing
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
- G11B7/005—Reproducing
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2403—Layers; Shape, structure or physical properties thereof
- G11B7/24035—Recording layers
- G11B7/24038—Multiple laminated recording layers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
- G11B2007/0009—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage
- G11B2007/0013—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage for carriers having multiple discrete layers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/007—Arrangement of the information on the record carrier, e.g. form of tracks, actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track
- G11B7/00736—Auxiliary data, e.g. lead-in, lead-out, Power Calibration Area [PCA], Burst Cutting Area [BCA], control information
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
- G11B7/126—Circuits, methods or arrangements for laser control or stabilisation
- G11B7/1267—Power calibration
Definitions
- the present invention relates to a multilayer recording medium having a plurality of recording layers, a reproducing apparatus for reproducing the multilayer recording medium, and a reproducing method.
- the numerical aperture NA of the objective lens mounted on the optical head is increased and the wavelength ⁇ of the light of the light source is shortened to make the spot diameter of the light collected by the objective lens It has been reduced.
- a multilayer recording medium having a plurality of recording layers has been proposed.
- FIG. 2 shows a conventional multilayer recording medium described in Patent Document 1 mentioned above.
- the multilayer recording medium shown in FIG. 2 eight information recording layers L0, L1,..., L7 are sequentially stacked in order from the farthest side from the reading side, and the thickness is t0 to t6 between each information recording layer. Seven spacers are arranged.
- the intensity reflectances R (n + 2) and R (n + 3) of the reflective film formed on the L (n + 2) layer and the L (n + 3) layer located in front of the L (n) layer are R (n + 2) ⁇ R (n + 3) ⁇ 0.01
- the optimum read power in each recording layer may differ due to the difference in laser light transmittance between the layer on the back side and the layer on the front side as viewed from the optical pickup side. (See, for example, Patent Document 2).
- each recording layer As the characteristics of each recording layer, when reproduction is performed using a laser beam of a predetermined reproduction power or more, the recorded data is deteriorated, so the reproduction power needs to be within a certain reproduction power. However, when the recording layer is increased to increase the capacity per disc, many recording layers are arranged so that the more layers that are farther from the reading side are arranged in front of each other. It is necessary to perform reproduction with the transmitted light. For example, in a multi-layered optical disc in which the recording layers L0, L1,..., L7 are sequentially stacked, the transmissivity of each layer is T0 to T7, and the individual reflectance of each layer is R0 to R7.
- the reflectance TR (L0) of the L0 layer is represented by the following equation (1).
- TR (L0) R0 x T1 2 x T2 2 x T3 2 x T4 2 x T5 2 x T6 2 x T7 2 (1)
- the reflectance of the L0 layer is the product of the square of the transmittance of the previous layer. For this reason, when the reflectance of a single layer, R0 to R7, is constant, the reflectance decreases toward the back layer. As the reflectance decreases, the amount of light returning from each layer to the light detector decreases, and the S / N decreases, which makes reproduction difficult. In order to cope with the problem, an approach has been taken to make the reflection of each layer substantially constant by increasing the reflectance as it goes to the back. With an optical disc of about two layers, this balance can be easily made to determine the optical structure of the disc.
- the reproduction power of the laser beam emitted from the optical pickup and incident on the optical disk is Pw
- the light P (L0) irradiated to the L0 layer of the optical disk formed of eight layers L0 to L7 has the formula It is represented by (2).
- P (L0) Pw x T1 x T2 x T3 x T4 x T5 x T6 x T7 (2)
- the light irradiated to the back layer is represented by the product of the transmittance T of the front layer and the reproduction power Pw. Since T is smaller than 1, the power of light irradiated to the layer decreases as the layer goes back. The fact that the power of light irradiated during reproduction decreases as the back layer decreases the possibility of deterioration of the recorded data due to the irradiation of reproduction light, so in principle the reproduction power is increased toward the back layer It becomes possible.
- the present invention is for solving the above-mentioned problems, and provides an information recording medium which does not deteriorate the recording data of the recording layer even when an unintended interlayer jump occurs in the multilayer recording medium. Further, the present invention provides an optical disk apparatus having a low error rate by reproducing such a multilayer optical disk with good S / N.
- the information recording medium of the present invention is a multilayer information recording medium provided with a plurality of information recording layers in which information is recorded, and at least one of the information recording layers has other reproduction power used when reproducing information. It differs from the information recording layer, and the substrate thickness between each information recording layer is equal to or more than a predetermined thickness.
- the substrate thickness is a thickness at which a light intensity reduction amount due to aberration is a predetermined value or more.
- the information recording medium of the present invention is an information recording medium provided with three or more information recording layers, and the n-th information recording layer L (counting in order from the information recording layer farthest from the reading side of the information recording medium)
- the reproduction power of the laser beam when reproducing information from n) is Pw (n) (here, n is an integer of 0 or more), and reproduces information from the n + a-th information recording layer L (n + a)
- the reproduction power of the laser beam at this time is Pw (n + a) (where a is an integer satisfying n + a 0 0 and a ⁇ 0), and the substrate thickness between the information recording layers is the reproduction power Pw (
- the light intensity when the information recording layer L (n + a) is irradiated with the laser beam n) is the light intensity when the information recording layer L (n + a) is irradiated with the laser beam with the reproduction power Pw (n + a)
- the thickness is as follows.
- the information recording medium of the present invention is an information recording medium provided with three or more information recording layers, and the n-th information recording layer L (counting in order from the information recording layer farthest from the reading side of the information recording medium)
- Pw (n) is the reproduction power of laser light when reproducing information from n) (where n is an integer greater than or equal to 0), and when reproducing information from the n + a-th information recording layer L (n + a)
- the reproduction power of the laser beam is Pw (n + a) (where a is an integer satisfying n + a ⁇ 0 and a ⁇ 0), and the information recording layer L (n) and the information recording layer L (n + a)
- the information recording medium has a substrate thickness D between 100 ⁇ Pw (n) / Pw (n + a) ⁇ -0.1238 ⁇ D 2 - 2.772 ⁇ D + 106.56 And Pw (n) P Pw (n + a) Meet.
- the reproduction method of the present invention is a reproduction method for reproducing information from the information recording medium, and when reproducing information from the information recording layer L (n), the laser beam of the reproduction power Pw (n) is The step of irradiating the information recording layer L (n) and the step of irradiating the information recording layer L (n + a) with the laser beam of the reproducing power Pw (n + a) when the information is reproduced from the information recording layer L (n + a) And the step of
- the reproducing apparatus is a reproducing apparatus for reproducing information from the information recording medium, comprising: an irradiating section for irradiating the information recording medium with a laser beam, the irradiating section comprising the information recording layer L (n)
- the information recording layer L (n) is irradiated with the laser beam of the reproducing power Pw (n)
- the irradiating unit reproduces the information from the information recording layer L (n + a)
- the laser beam of the reproduction power Pw (n + a) is irradiated to the information recording layer L (n + a).
- the method of manufacturing an information recording medium according to the present invention is a method of manufacturing an information recording medium including k information recording layers (k is an integer of 3 or more), and an objective lens having a numerical aperture of 0.84 to 0.86.
- k information recording layers in which information can be reproduced using a laser beam having a wavelength of 400 to 410 nm on a substrate having a thickness of 1.1 mm, and between the information recording layer and the information recording layer Forming k-1 intermediate layers, and forming a protective layer having a thickness of 0.1 mm or less on the k-th information recording layer counted from the substrate side.
- the reproduction direction of one of the odd-numbered information recording layer and the even-numbered information recording layer counted from the substrate side is the inner peripheral side from the outer peripheral side of the information recording medium
- the other reproduction direction of the odd-numbered and even-numbered information recording layers is from the inner circumference side to the outer circumference side of the information recording medium.
- the optimum reproduction powers of the respective recording layers are all different from one another or differ only in part of the recording layers, and the substrate thickness between the respective recording layers is equal to or more than the predetermined thickness. According to this configuration, it is possible to realize an information recording medium in which the recording data is not deteriorated or erased even if the relationship between the reproduction powers of the recording layers is unintentionally caused by the interlayer jump.
- FIG. 1 shows a playback device according to an embodiment of the present invention.
- FIG. 1 is a diagram showing an exemplary configuration of a multilayer disc according to an embodiment of the present invention.
- FIG. 2 is a view showing an example of the configuration of a single layer disc according to an embodiment of the present invention.
- FIG. 2 is a diagram showing an exemplary configuration of a dual layer disc according to an embodiment of the present invention.
- FIG. 2 is a diagram showing an example of the configuration of a three-layer disc according to an embodiment of the present invention.
- FIG. 5 is a diagram showing an example of the configuration of a four-layer disc according to an embodiment of the present invention.
- FIG. 2 is a diagram showing a physical configuration of an optical disc according to an embodiment of the present invention.
- FIG. 13 (a) is a diagram showing an example of a 25 GB BD according to an embodiment of the present invention, and FIG.
- FIG. 13 (b) is a diagram showing an example of an optical disc with a higher recording density than the 25 GB BD according to an embodiment of the present invention. It is. It is a figure which shows a mode that the light beam is irradiated to the mark row recorded on the track
- FIG. 7 is a diagram showing the relationship between OTF and shortest recording mark in the case of 25 GB recording capacity according to an embodiment of the present invention.
- FIG. 7 is a diagram showing an example in which the spatial frequency of the shortest mark (2T) is higher than the OTF cutoff frequency and the amplitude of the 2T reproduction signal is 0 according to the embodiment of the present invention.
- FIG. 1 shows the structure of a multilayer information recording medium (optical disc) 100 according to an embodiment of the present invention.
- Constituent elements of the same type as the constituent elements of the multilayer information recording medium shown in FIG. 2 are assigned the same reference numerals, and the detailed description will not be repeated.
- the multilayer information recording medium 100 includes three or more recording layers in which information is recorded.
- L0 to L3 indicate the respective recording layers
- t0 to t2 indicate the substrate thickness between the respective recording layers. Since an intermediate layer (Spacer Layer) is provided between the recording layer and the recording layer, the substrate thickness means the thickness of the intermediate layer.
- Pw0 to Pw3 indicate the optimum reproduction powers in the recording layers L0 to L3.
- FIG. 3 is a view showing the relationship between the substrate thickness and the light intensity.
- the light intensity represents the power of light incident per unit area of the recording layer.
- the light intensity at the substrate thickness at which the laser beam is most efficiently condensed on the target recording layer is It is 100%.
- a change in light intensity is a phenomenon substantially equivalent to a change in reproduction power. That is, for the recording layer, it can be said that a change in light intensity due to a change in substrate thickness and a change in laser light output under a constant substrate thickness condition are substantially equivalent events.
- This change in light intensity is roughly proportional to the cube of NA and the wavelength.
- the layer thickness is 20 to 30 ⁇ m or less and the base layer thickness of the recording layer with the largest base thickness is about 100 ⁇ m and the recording layer is disposed on the thinner side than 100 ⁇ m.
- NA> 0.8 a change in light intensity of about 30% occurs even between layers separated by about 10 ⁇ m.
- the substrate thickness between the recording layers is determined from the relationship between the substrate thickness and the light intensity.
- the predetermined thickness is a thickness at which the amount of decrease in light intensity due to aberration is equal to or greater than a predetermined value. Details will be described later.
- FIG. 4 is a view showing the relationship between the substrate thickness and the light intensity.
- the optimum reproduction power of the laser beam when reproducing information from the recording layer L0 is Pw0, and the light intensity when the laser beam is condensed on the recording layer L0 is 100%.
- the optimum reproduction powers of the laser beam when reproducing information from the recording layers L1, L2 and L3 are Pw1, Pw2 and Pw3, respectively.
- the light intensity when the laser beam of reproduction power Pw1 is condensed on the recording layer L1 is represented by 80%.
- the substrate thickness is set such that the light intensity when the laser beam of the reproduction power Pw0 is condensed on the recording layer L1 is 80% or less. That is, the substrate thickness is set such that the light intensity when the laser beam of the reproduction power Pw1 is condensed on the recording layer L1 is equal to or less than the light intensity.
- the light intensity when the laser beam with the reproduction power Pw2 is condensed on the recording layer L2 is represented by 70%.
- the substrate thickness is set such that the light intensity when the laser beam of the reproduction power Pw1 is condensed on the recording layer L2 is 70% or less. That is, the substrate thickness is set such that the light intensity when the laser beam of the reproduction power Pw2 is condensed on the recording layer L2 is equal to or less than the light intensity.
- the substrate thickness may be set such that the light intensity after the interlayer jump matches the optimum light intensity of the recording layer, or the substrate thickness is set so as to be smaller than the optimum light intensity. May be
- the substrate thickness is set such that the light intensity after the interlayer jump is equal to or less than the optimum light intensity of the recording layer, but the light intensity or less at which data deterioration occurs in the recording layer
- the substrate thickness may be set to be
- the thickness between the recording layers is obtained using the relationship between the substrate thickness change and the light intensity change
- the thickness may be obtained using a simple approximation.
- BD Blu-ray Disc
- approximate equations (3) and (4) are obtained from the relationship between substrate thickness, light intensity and reproduction power, and these equations are used to It becomes possible to determine the substrate thickness.
- FIG. 5 is a diagram showing the relationship between the substrate thickness and the light intensity by an approximate expression.
- S -0.1238 ⁇ d 2 - 2.772 ⁇ d + 106.56 (3)
- S is the light intensity [%]
- d is the substrate thickness change amount [um] from the substrate thickness at which the light intensity is 100%.
- d is a positive integer.
- the reproduction power of the laser light when reproducing information from the n-th information recording layer L (n) in order from the recording layer farthest from the reading side of the optical disc 100 (upper side in FIG. 1) is Pw (n) I assume.
- n is an integer of 0 or more.
- the recording layer L0 farthest from the reading side (the deepest side) is represented by L (0)
- the reproduction power Pw0 is represented by Pw (0).
- the reproduction power of the laser beam when reproducing information from the n + a-th information recording layer L (n + a) is Pw (n + a).
- a is an integer that satisfies n + a ⁇ 0 and a ⁇ 0.
- the recording layer L1 corresponds to that recording layer.
- the reproduction power Pw (n) is larger than the reproduction power Pw (n + a)
- the light intensity when the laser beam of the reproduction power Pw (n) is irradiated to the information recording layer L (n + a) is the reproduction power Pw (n + a).
- the substrate thickness D is set such that the left side of the equation (4) has an appropriate ratio.
- a is a negative integer and the reproduction power Pw (n + a) is larger than the reproduction power Pw (n)
- the light intensity when the information recording layer L (n) is irradiated with the laser light of the reproduction power Pw (n + a) is The light intensity when the information recording layer L (n) is irradiated with the laser beam of the reproduction power Pw (n) can be obtained.
- the reproduction power Pw (n + a) is larger than the reproduction power Pw (n)
- the intensity may be equal to or less than the light intensity when the information recording layer L (n) is irradiated with the laser beam of the reproduction power Pw (n).
- fills such conditions can be calculated
- FIG. 6 shows a playback device 400 according to an embodiment of the present invention.
- the reproduction device 400 is a device that reproduces information from the optical disc 100.
- the reproducing apparatus 400 includes an optical pickup 402, a semiconductor laser control unit 403 and a servo processing unit 404 for controlling the optical pickup 402, a reproduction signal processing unit 405 for processing a reproduction signal output from the optical pickup, and a central processing unit 406. And The central processing unit 406 controls the operation of a plurality of components included in the playback device 400.
- the central control unit 406 controls the semiconductor laser control unit 403, the servo processing unit 404, and the reproduction signal processing unit 405 based on a control signal output from an external computer (not shown).
- the semiconductor laser control unit 403 sets the reproduction power and the high frequency superimposition, causes the optical pickup (irradiation unit) 402 to emit laser light with a predetermined laser power, and irradiates the optical disk 100 with the laser light.
- the optical pickup 402 irradiates the information recording layer L (n) with laser light of reproduction power Pw (n).
- the optical pickup 402 irradiates the information recording layer L (n + a) with a laser beam of reproduction power Pw (n + a).
- the servo processing unit performs tracking control and focus control using the signal detected by the optical pickup 402, and performs control such that the optical pickup 402 accurately focuses and tracks on the information recording medium 100.
- the reproduction signal processing unit 405 performs data reproduction signal processing and wobble signal processing, and performs processing such as data reproduction and physical address reproduction.
- the recording medium has a portion where various information related to the recording medium is stored, and the type of the recording medium is determined based on the information read from the portion, and setting is performed so as to have a predetermined reproduction power.
- the reproduction power may be changed according to each recording layer. In the case where an unintended interlayer jump occurs in such a multilayer recording medium, the reproduction power to the recording layer after the interlayer jump may be increased to cause deterioration of the recorded data.
- the reproduction power in each recording layer is determined using a phenomenon in which the light intensity decreases due to the change in the substrate thickness between the recording layers.
- the semiconductor laser control unit 403 can irradiate each recording layer with a laser beam having an appropriate light intensity by setting the reproduction power according to the specified substrate thickness.
- the reproduction power information of each recording layer may be stored in the memory of the central control unit 406.
- the reproduction power information is the light intensity when the laser light of the reproduction power for one recording layer is condensed on another recording layer using the relationship between the substrate thickness and the light intensity shown in FIG.
- the reproduction power is calculated and stored so that the laser light of the reproduction power for the other recording layer has the same light intensity as when it is condensed on the other recording layer.
- the reproduction power may be set after the determination.
- the reproduction power information is the light intensity when the laser light of the reproduction power for one recording layer is focused on another recording layer, and the laser light of the reproduction power for the other recording layer is another recording It may indicate the reproduction power to be equal to or less than the light intensity when condensed on the layer.
- the reproduction power information indicates the reproduction power so that the light intensity after the interlayer jump is less than the appropriate light intensity of the recording layer
- the reproduction power information is less than the light intensity at which the deterioration occurs in the recording layer. It may indicate the reproduction power.
- the reproduction power may be determined and stored using the relationship between the substrate thickness change and the light intensity as shown in FIG. 3 and FIG. 4, or as shown in FIG. 5 or equation (3) or equation (4).
- the reproduction power may be determined and stored using the approximate expression shown in equation (5).
- the reproduction power that can be set for each recording layer of the recording medium ranges from the reproduction power as small as the reproduction signal quality does not deteriorate to the reproduction power as large as the deterioration of the recording data does not occur. It may be defined. In that case, the reproduction power of each recording layer may be set so that deterioration of the recording data does not occur within the reproduction power range that can be set in each recording layer. In the case where the reproduction power is set close to the upper limit, there is a possibility that deterioration of the recorded data can not be completely avoided when an unintended interlayer jump occurs, but it is possible to reduce the deterioration.
- BD Blu-ray Disc
- BD-ROM which is a reproduction only type
- BD-R which is a write-once recording type and write-once type
- BD-RE which is a rewrite recording type according to the characteristics of the recording film.
- the present invention is applicable to any type of recording medium such as ROM (reproduction only type), R (write-once type / write once type), and RE (rewritable type) in optical disks of BD and other standards.
- the main optical constants and physical formats of Blu-ray Disc can be found in the white paper published on “Blu-ray Disc Reader” (Am Publishing) or on the website of the Blu-ray Association (http://www.blu-raydisc.com/). It is disclosed.
- BD laser light with a wavelength of approximately 405 nm (400 to 410 nm if the tolerance of the error range is ⁇ 5 nm with respect to the standard value of 405 nm) and the numerical aperture (NA: Numerical Aperture) is approximately 0.85 (standard value) Assuming that the tolerance of the error range is ⁇ 0.01 with respect to 0.85, an objective lens of 0.84 to 0.86) is used.
- the track pitch of BD is approximately 0.32 ⁇ m (0.310 to 0.330 ⁇ m when the tolerance of the error range is ⁇ 0.010 ⁇ m with respect to the standard value 0.320 ⁇ m), and the recording layer has one or two layers. Layers are provided.
- the recording surface of the recording layer has a single-sided or single-sided two-layer structure from the laser incident side, and the distance from the surface of the protective layer of BD to the recording surface is 75 ⁇ m to 100 ⁇ m.
- the modulation method of the recording signal uses 17PP modulation, and the mark of the shortest mark (2T mark: T is the period of the reference clock (the reference period of modulation when recording the mark according to a predetermined modulation rule)) of the mark to be recorded
- T is the period of the reference clock (the reference period of modulation when recording the mark according to a predetermined modulation rule)) of the mark to be recorded
- the length is 0.149 ⁇ m (or 0.138 ⁇ m) (channel bit length: T is 74.50 nm (or 69.00 nm)).
- Recording capacity is single-sided single layer 25GB (or 27GB) (more specifically, 25.025GB (or 27.020GB)), or single-sided two-layer 50GB (or 54GB) (more specifically, 50.050GB (or 54) .040 GB)).
- the channel clock frequency is 66 MHz (channel bit rate 66.000 Mbit / s) at the standard speed (BD1x) transfer rate, 264 MHz (channel bit rate 264.000 Mbit / s) at the quadruple speed (BD4 x), 6
- the transfer rate of double speed (BD6x) is 396 MHz (channel bit rate 396.000 Mbit / s), and that of 8-fold speed (BD8x) is 528 MHz (channel bit rate 528.000 Mbit / s).
- the standard linear velocity (reference linear velocity, 1x) is 4.917 m / sec (or 4.554 m / sec).
- the linear velocities of 2.times. (2.times.), 4.times. (4.times.), 6.times. (6.times.) And 8.times. (8.times.) are 9.834 m / sec, 19.668 m / sec, 29.502 m / sec and 39. 9 m. It is 336 m / sec.
- the linear velocity higher than the standard linear velocity is generally a positive integer multiple of the standard linear velocity, but is not limited to an integer, and may be a positive real multiple.
- a linear velocity slower than standard linear velocity may also be defined, such as 0.5x (0.5x).
- BD BD of about 25 GB (or about 27 GB) per layer
- it is mainly for recording of 1 layer or 2 layers as a further increase in capacity.
- High-density BDs having a capacity of approximately 32 GB or approximately 33.4 GB, and BDs having three or four layers have also been studied, and these will also be described below.
- the illustrated optical disc is configured of an information recording layer 502 of (n + 1) layers (n is an integer of 0 or more).
- the structure of the optical disk is such that a cover layer 501, (n + 1) information recording layers (Ln to L0 layers) 502, and a substrate 500 are sequentially stacked from the surface on which the laser beam 505 is incident. It is done.
- an interlayer 503 serving as an optical buffer is inserted between the (n + 1) information recording layers 502. That is, the reference layer (L0) is provided at the farthest position (the position farthest from the light source) at a predetermined distance from the light incident surface, and recording is performed so as to increase the layer from the reference layer (L0) to the light incident surface side. Layers are stacked (L1, L2,..., Ln).
- the distance from the light incident surface to the reference layer L0 in the multilayer disc is made substantially the same as the distance from the light incident face to the recording layer in the single layer disc (for example, about 0.1 mm). May be
- the distance to the deepest layer is made constant (that is, almost the same distance as in the single layer disc), regardless of whether it is a single layer or multiple layers. Compatibility with respect to access to the reference layer can be maintained.
- the innermost layer is most affected by the tilt, but the number of layers increases by making the distance to the innermost layer approximately the same distance as the single layer disc. However, the distance to the innermost layer will not increase.
- the traveling direction of the spot (or also referred to as track direction or spiral direction), it may be a parallel path or an opposite path.
- the reproduction direction is the same in all layers. That is, the traveling direction of the spot proceeds from the inner periphery to the outer periphery in all layers, or from the outer periphery to the inner periphery in all layers.
- the reproduction direction is reversed between a certain layer and a layer adjacent to that layer. That is, when the reproduction direction in the reference layer (L0) is a direction from the inner periphery to the outer periphery, the reproduction direction in the recording layer L1 is a direction from the outer periphery to the inner periphery, and in the recording layer L2, from the inner periphery to the outer periphery It is a direction. That is, the reproduction direction is a direction from the inner periphery to the outer periphery in the recording layer Lm (m is 0 and an even number), and is a direction from the outer periphery to the inner periphery in the recording layer Lm + 1.
- the recording layer Lm (m is 0 and an even number), it is a direction from the outer periphery to the inner periphery and in the recording layer Lm + 1, it is a direction from the inner periphery to the outer periphery.
- the thickness of the protective layer (cover layer) is set thinner as the numerical aperture NA increases, so that the focal length becomes shorter and the influence of the spot distortion due to the tilt can be suppressed.
- the numerical aperture NA is set to 0.45 for CD, 0.65 for DVD, and approximately 0.85 for BD.
- the thickness of the protective layer may be 10 to 200 ⁇ m. More specifically, a transparent protective layer of about 0.1 mm in the case of a single-layer disc, and an intermediate layer of about 0.025 mm in the case of a double-layer disc of about 0.075 mm. ) May be provided. If the disc has three or more layers, the thickness of the protective layer and / or the intermediate layer may be thinner.
- FIG. 8 shows an example of the configuration of a single-layer disc
- FIG. 9 shows an example of the configuration of a two-layer disc
- FIG. 10 shows an example of the configuration of a three-layer disc
- FIG. 8 when the distance from the light irradiation surface to the reference layer L0 is constant, the total thickness of the disc is approximately 1.2 mm in any of FIGS. 9 to 11 (when including label printing and the like, 1
- the thickness of the substrate 500 is approximately 1.1 mm
- the distance from the light irradiation surface to the reference layer L0 is approximately 0.1 mm.
- These multilayer disks (disks having a recording layer of k layers, k is an integer of 1 or more) can be manufactured by the following process.
- information can be reproduced by irradiating a laser with a wavelength of 400 nm or more and 410 nm or less through an objective lens with a numerical aperture of 0.84 or more and 0.86 or less on a substrate with a thickness of approximately 1.1 mm.
- K recording layers are formed.
- k ⁇ 1 intermediate layers are formed between the recording layer and the recording layer.
- a protective layer having a thickness of 0.1 mm or less is formed on the k-th recording layer (in the case of a multilayer disc, the recording layer farthest from the substrate) counting from the substrate side.
- the reproduction direction is from the inner peripheral side to the outer peripheral side of the disc.
- Concentric or spiral tracks are formed in the direction of.
- the j-th (j is 1 or more and k or less even numbered) recording layers are formed counting from the substrate side, concentric circles are formed so that the reproduction direction is from the outer peripheral side to the inner peripheral side of the disc. Or a spiral track is formed.
- the information recording layers Pw (n) are the reproduction power of the n-th information recording layer L (n) in order from the recording layer farthest from the reading side of the information recording medium, and the information recording layer is the most reading side of the information recording medium.
- Pw (n + a) is the reproduction power of the n + a-th information recording layer L (n + a), counted sequentially from the distant recording layer, and the substrate thickness between the information recording layer L (n) and the information recording layer L (n + a)
- D 100 ⁇ Pw (n) / Pw (n + a) ⁇ ⁇ 0.1238 ⁇ D 2 ⁇ 2.772 ⁇ D + 106.56
- Pw (n) P Pw (n + a) (Here, n is an integer of 0 or more, a is an integer satisfying n + a ⁇ 0 and
- Reproduction of such a multi-layered disc (a disc having a recording layer of k layers, k is an integer of 1 or more) is performed by a reproducing apparatus (or reproducing method) having the following configuration.
- a track is formed in each of the k recording layers, and various regions can be assigned to at least one of the tracks.
- the k recording layers are formed by an optical head that emits a laser having a wavelength of 400 nm or more and 410 nm or less through an objective lens having a numerical aperture of 0.84 or more and 0.86 or less from the surface side of the protective layer. Information can be reproduced from each of them.
- the reproduction apparatus includes an irradiation unit that emits a laser beam.
- the irradiation means reproduces information by irradiating the n-th information recording layer L (n) in order from the recording layer farthest from the reading side of the information recording medium to the n-th information recording layer L (n) Do. Further, the irradiating means irradiates the laser light of reproduction power Pw (n + a) to the n + a information recording layer L (n + a) in order from the recording layer farthest from the reading side of the information recording medium.
- n is an integer of 0 or more
- a is an integer satisfying n + a ⁇ 0, and a ⁇ 0.
- FIG. 12 shows the physical configuration of an optical disc 100 according to an embodiment of the present invention.
- a large number of tracks 2 are formed concentrically or spirally on the disk-shaped optical disc 100, and a large number of finely divided sectors are formed on each track 2.
- data is recorded on each track 2 in units of blocks 3 of a predetermined size.
- the recording capacity per information recording layer is expanded as compared with a conventional optical disc (for example, a 25 GB BD).
- the expansion of the recording capacity is realized by improving the recording linear density, for example, by shortening the mark length of the recording mark recorded on the optical disc.
- "improving the recording linear density” means shortening the channel bit length.
- the channel bit has a length corresponding to the period T of the reference clock (the reference period T of modulation in the case of recording a mark according to a predetermined modulation rule).
- the optical disc 100 may be multilayered. However, in the following, for convenience of description, only one information recording layer is mentioned.
- the mark length differs for each layer, and the mark length is uniform in the same layer.
- the recording linear density may be made different for each layer.
- the track 2 is divided into blocks for each recording unit 64 kB (kilobyte) of data, and block address values are assigned in order.
- the blocks are divided into subblocks of a predetermined length, and three subblocks constitute one block.
- the sub-blocks are assigned sub-block numbers 0 to 2 sequentially from the front.
- FIG. 13A shows an example of a 25 GB BD.
- the wavelength of the laser 123 is 405 nm
- the numerical aperture (Numeric Aperture; NA) of the objective lens 220 is 0.85.
- the recording data is recorded on the track 2 of the optical disc as a mark train 120, 121 of physical change.
- the shortest one of the mark lines is called the "shortest mark”.
- the mark 121 is the shortest mark.
- the physical length of the shortest mark 121 is 0.149 um. This corresponds to about 1 / 2.7 of DVD, and the light beam identifies the recording mark even if the laser resolution is increased by changing the wavelength parameter (405 nm) and the NA parameter (0.85) of the optical system. It is approaching the limit of optical resolution which is the limit that can be done.
- FIG. 14 shows a state in which a light beam is irradiated to a mark row recorded on a track.
- the light spot 30 becomes about 0.39 um by the above-mentioned optical system parameter.
- the recording mark becomes relatively smaller than the spot diameter of the light spot 30, so that the resolution of reproduction is deteriorated.
- FIG. 13 (b) shows an example of an optical disc having a higher recording density than a 25 GB BD.
- the wavelength of the laser 123 is 405 nm
- the numerical aperture (NA) of the objective lens 220 is 0.85.
- the physical length of the shortest mark 125 is 0.1115 um (or 0.11175 um) among the mark rows 125 and 124 of this disk.
- the spot diameter is about 0.39 um, but the recording mark becomes relatively small and the mark interval becomes narrow, so that the resolution of reproduction becomes worse.
- the amplitude of the reproduction signal when the recording mark is reproduced by the light beam decreases as the recording mark becomes shorter, and becomes zero at the limit of the optical resolution.
- the reciprocal of the period of the recording mark is called a spatial frequency, and the relationship between the spatial frequency and the signal amplitude is called OTF (Optical Transfer Function).
- OTF Optical Transfer Function
- the signal amplitude decreases approximately linearly as the spatial frequency increases.
- the limit frequency of reproduction at which the signal amplitude becomes zero is called OTF cutoff.
- FIG. 15 is a graph showing the relationship between OTF and the shortest recording mark in the case of 25 GB recording capacity.
- the spatial frequency of the shortest mark of BD is about 80% with respect to the OTF cutoff, and is close to the OTF cutoff. Also, it can be seen that the amplitude of the reproduction signal of the shortest mark is also very small, about 10% of the maximum detectable amplitude.
- the recording capacity of the BD corresponds to about 31 GB.
- the resolution of the laser may be limited or exceeded, and the reproduction amplitude of the reproduction signal may be reduced. It becomes an area where the SN ratio is rapidly deteriorated.
- the recording linear density of the high recording density optical disc shown in FIG. 13 (b) is such that the frequency of the shortest mark of the reproduction signal is near the OTF cutoff frequency (if it is below the OTF cutoff frequency but not significantly below the OTF cutoff frequency). And the OTF cut-off frequency or higher.
- FIG. 16 is a graph showing an example of the relationship between the signal amplitude and the spatial frequency when the spatial frequency of the shortest mark (2T) is higher than the OTF cutoff frequency and the amplitude of the 2T reproduction signal is 0. It is.
- the spatial frequency of 2T of the shortest mark length is 1.12 times the OTF cut-off frequency.
- P (TM + TS) nm when “P” represents (shortest mark length + shortest space length).
- the reference T becomes smaller to become, the spatial frequency of the shortest mark will exceed the OTF cut-off frequency.
- the SN ratio deterioration due to the multi-layering of the information recording layer may not be acceptable from the viewpoint of the system margin.
- the frequency of the shortest recording mark exceeds the OTF cutoff frequency, the SN ratio deterioration becomes remarkable.
- the frequency of the reproduction signal of the shortest mark and the OTF cut-off frequency are compared and described regarding the recording density, but when the density is further advanced, the next shortest mark (and the shortest one after another) Recording density (recording linear density, recording capacity) corresponding to the relationship between the frequency of the reproduced signal of the mark (more than the next shortest mark) and the OTF cut-off frequency, based on the same principle as above May be set.
- a specific recording capacity per layer in a BD having specifications such as a wavelength of 405 nm and a numerical aperture of 0.85 for example, when the spatial frequency of the shortest mark is near the OTF cutoff frequency, for example, 29 GB (for example, 29.0 GB ⁇ 0.5 GB, or 29 GB ⁇ 1 GB) or more, or approximately 30 GB (eg, 30.0 GB ⁇ 0.5 GB, or 30 GB ⁇ 1 GB) or more, or approximately 31 GB (or more).
- the recording capacity per layer when the spatial frequency of the shortest mark is equal to or higher than the OTF cutoff frequency
- approximately 32 GB for example, 32.0 GB ⁇ 0.5 GB, or 32 GB ⁇ 1 GB
- Approximately 33 GB for example, 33.0 GB ⁇ 0.5 GB, or 33 GB ⁇ 1 GB
- approximately 33.3 GB for example, 33.3 GB ⁇ 0.5 GB, or 33.3 GB ⁇ 1 GB or more
- approximately 33.4 GB eg, 33.4 GB ⁇ 0.5 GB, or 33.4 GB ⁇ 1 GB
- approximately 34 GB eg, 34.0 GB ⁇ 0.5 GB, or 34 GB ⁇ 1 GB
- 35GB for example, 35.0GB ⁇ 0.5GB, or 35GB It is possible to assume ⁇ 1 GB or more.
- the recording capacity of about 100 GB (99.9 GB) can be realized with three layers, and if about 33.4 GB, the recording capacity of 100 GB (100.2 GB) or more with three layers is realized. realizable. This is almost the same as the recording capacity when the 25 GB BD has four layers.
- the disk configuration there is an option of setting the disk configuration to a four-layer structure of 25 GB per layer or a three-layer structure of 33 to 34 GB per layer.
- the multi-layering is accompanied by the reduction of the reproduction signal amplitude in each recording layer (the deterioration of the SN ratio), the influence of multilayer stray light (a signal from an adjacent recording layer) and the like. Therefore, by using a 33-34 GB triple-layer disc instead of a 25-GB 4-layer disc, the influence of such stray light is minimized, ie, with a smaller number of layers (three layers instead of four layers). It becomes possible to realize 100 GB.
- a disc manufacturer who wants to realize about 100 GB while avoiding the multi-layering as much as possible can select the 33-34 GB triple-layering.
- a disc manufacturer who wants to realize about 100 GB with the conventional format (recording density 25 GB) can select 25 GB 4-layer. In this way, manufacturers having different purposes can realize their respective goals by providing different configurations, and can provide a degree of freedom in disk design.
- the recording density per layer is about 30 to 32 GB, although it does not reach 100 GB (about 90 to 96 GB) in a three-layer disc, 120 GB or more can be realized in a four-layer disc.
- the recording density is approximately 32 GB, a four-layer disc can realize a recording capacity of approximately 128 GB.
- the number 128 is also a number matched to a power of 2 (2 to the power of 7) which is convenient for computer processing.
- the reproduction characteristic for the shortest mark is not severer here.
- the disc manufacturer is provided with a combination of the plurality of types of recording density and the number of layers.
- Design freedom can be given. For example, for manufacturers wishing to increase the capacity while suppressing the influence of multi-layering, the option of manufacturing an about 100 GB three-layer disc by tri-layering of 33 to 34 GB is given an option to suppress the influence of reproduction characteristics. For manufacturers wishing to increase the capacity, it is possible to give an option to manufacture a four-layer disc of about 120 GB or more by making four layers of 30 to 32 GB.
- the information recording medium of the present invention is a multilayer information recording medium provided with a plurality of information recording layers in which information is recorded, and at least one of the information recording layers is used to reproduce information.
- the reproduction power used is different from that of the other information recording layers, and the substrate thickness between the information recording layers is equal to or greater than a predetermined thickness.
- the substrate thickness is a thickness at which a light intensity reduction amount due to aberration is a predetermined value or more.
- the information recording medium of the present invention is an information recording medium provided with three or more information recording layers, and the n-th information recording layer L (counting in order from the information recording layer farthest from the reading side of the information recording medium)
- the reproduction power of the laser beam when reproducing information from n) is Pw (n) (here, n is an integer of 0 or more), and reproduces information from the n + a-th information recording layer L (n + a)
- the reproduction power of the laser beam at this time is Pw (n + a) (where a is an integer satisfying n + a 0 0 and a ⁇ 0), and the substrate thickness between the information recording layers is the reproduction power Pw (
- the light intensity when the information recording layer L (n + a) is irradiated with the laser beam n) is the light intensity when the information recording layer L (n + a) is irradiated with the laser beam with the reproduction power Pw (n + a)
- the thickness is as follows.
- the information recording medium of the present invention is an information recording medium provided with three or more information recording layers, and the n-th information recording layer L (counting in order from the information recording layer farthest from the reading side of the information recording medium)
- Pw (n) is the reproduction power of laser light when reproducing information from n) (where n is an integer greater than or equal to 0), and when reproducing information from the n + a-th information recording layer L (n + a)
- the reproduction power of the laser beam is Pw (n + a) (where a is an integer satisfying n + a ⁇ 0 and a ⁇ 0), and the information recording layer L (n) and the information recording layer L (n + a)
- the information recording medium has a substrate thickness D between 100 ⁇ Pw (n) / Pw (n + a) ⁇ -0.1238 ⁇ D 2 - 2.772 ⁇ D + 106.56 And Pw (n) P Pw (n + a) Meet.
- the reproduction method of the present invention is a reproduction method for reproducing information from the information recording medium, and when reproducing information from the information recording layer L (n), the laser beam of the reproduction power Pw (n) is The step of irradiating the information recording layer L (n) and the step of irradiating the information recording layer L (n + a) with the laser beam of the reproducing power Pw (n + a) when the information is reproduced from the information recording layer L (n + a) And the step of
- the reproducing apparatus is a reproducing apparatus for reproducing information from the information recording medium, comprising: an irradiating section for irradiating the information recording medium with a laser beam, the irradiating section comprising the information recording layer L (n)
- the information recording layer L (n) is irradiated with the laser beam of the reproducing power Pw (n)
- the irradiating unit reproduces the information from the information recording layer L (n + a)
- the laser beam of the reproduction power Pw (n + a) is irradiated to the information recording layer L (n + a).
- the method of manufacturing an information recording medium according to the present invention is a method of manufacturing an information recording medium including k information recording layers (k is an integer of 3 or more), and an objective lens having a numerical aperture of 0.84 to 0.86.
- k information recording layers in which information can be reproduced using a laser beam having a wavelength of 400 to 410 nm on a substrate having a thickness of 1.1 mm, and between the information recording layer and the information recording layer Forming k-1 intermediate layers, and forming a protective layer having a thickness of 0.1 mm or less on the k-th information recording layer counted from the substrate side.
- the reproduction direction of one of the odd-numbered information recording layer and the even-numbered information recording layer counted from the substrate side is the inner peripheral side from the outer peripheral side of the information recording medium
- the other reproduction direction of the odd-numbered and even-numbered information recording layers is from the inner circumference side to the outer circumference side of the information recording medium.
- the optical recording medium of the present invention is a multilayer recording medium in which a plurality of recording layers in which information is recorded is formed, and the reproduction power at the time of reproducing each recording layer is different from all or only a part of the recording layers.
- the substrate thickness between the recording layers is set to a predetermined thickness or more.
- the substrate thickness between the recording layers is a thickness at which the amount of decrease in light intensity due to aberration is a predetermined value or more.
- the light intensity at the n + a layer is n + a-th when the reproduction power is Pw (n) in the n-th recording layer L (n).
- the thickness is the same as the reproduction power Pw (n + a) of the layer L (n + a) (here, n is an integer of 0 or more and a is an integer of 0 to n or more).
- the light intensity at the n + a layer is n + a-th when the reproduction power is Pw (n) in the n-th recording layer L (n).
- the thickness is equal to or less than the reproduction power Pw (n + a) of the layer L (n + a) (here, n is an integer of 0 or more and a is an integer of 0 to n or more).
- the reproducing method according to the present invention is a reproducing method for reproducing a multilayer recording medium in which a plurality of recording layers in which information is recorded is formed, and the reproduction power of each recording layer is set to be different only in all or a part of the layers.
- the reproduction power of each recording layer is obtained from the substrate thickness information between the recording layers.
- the reproduction power of each recording layer is the n + a-th recording at the light intensity at the n + a layer.
- the reproduction power is the same as the reproduction power Pw (n + a) of the layer L (n + a) (here, n is an integer of 0 or more and a is an integer of 0 to n or more).
- the reproduction power of each recording layer is the n + a-th recording at the light intensity at the n + a layer.
- the reproduction power is set to be equal to or less than the reproduction power Pw (n + a) of the layer L (n + a) (here, n is an integer of 0 or more and a is an integer of 0 to n or more).
- the reproducing apparatus is a reproducing apparatus for reproducing a multilayer recording medium in which a plurality of recording layers in which information is recorded is formed, wherein the reproduction power of each recording layer is set to be different only in all or part of the layers.
- the reproduction power of each recording layer is obtained from the substrate thickness information between the recording layers.
- the reproduction power of each recording layer is the n + a-th recording at the light intensity at the n + a layer.
- the reproduction power is the same as the reproduction power Pw (n + a) of the layer L (n + a) (here, n is an integer of 0 or more and a is an integer of 0 to n or more).
- the reproduction power of each recording layer is the n + a-th recording at the light intensity at the n + a layer.
- the reproduction power is set to be equal to or less than the reproduction power Pw (n + a) of the layer L (n + a) (here, n is an integer of 0 or more and a is an integer of 0 to n or more).
- the recording medium according to the present invention can avoid deterioration of recording data even when an unintended interlayer jump occurs, and is particularly useful in an optical disc system using a multilayer recording medium.
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Abstract
Description
R(n+2)×R(n+3)<0.01
を満たすため、t1>t0>t3=t5>t2=t4=t6の関係としている。そのため、t6=t4=t2且つt5=t3と設定することが可能となり、多重反射を軽減するために必要なスペーサーの種類を7種類から4種類に減らすことが可能となる。
TR(L0) = R0× T12×T22×T32×T42×T52×T62×T72 (1)
P(L0) = Pw×T1×T2×T3×T4×T5×T6×T7 (2)
100 × Pw(n) / Pw(n+a) ≧ -0.1238 × D2 - 2.772 × D + 106.56
および
Pw(n) ≦ Pw(n+a)
を満たす。
100 × Pw(n) / Pw(n+a) ≧ -0.1238 × D2 - 2.772 × D + 106.56
および
Pw(n) ≦ Pw(n+a)
を満たす。
図1は、本発明の実施形態における多層情報記録媒体(光ディスク)100の構造を示す。図2に示す多層情報記録媒体の構成要素と同じ種類の構成要素に関しては、同じ符号を付し、詳細な説明の繰り返しは省略する。
S = -0.1238×d2 - 2.772×d + 106.56 (3)
ここで、Sは光強度[%]、dは光強度100%となる基材厚からの基材厚変化量[um]である。ここで、dは正の整数である。
100×Pw(n)/Pw(n+a) = -0.1238×D2 - 2.772×D + 106.56 (4)
から求めることができる。ここで、Pw(n)≦Pw(n+a)であり、Pw(n)/Pw(n+a)の単位は[%]である。例えば、Pw(n)=Pw(n+a)のとき(すなわち、Pw(n)/Pw(n+a)の比率が1のとき)、式(4)の左辺は100[%]である。また、nは0以上の整数、aはn+a≧0、かつ、a≠0を満たす整数である。
100×Pw(n)/Pw(n+a) ≧ -0.1238×D2 - 2.772×D + 106.56 (5)
図6は、本発明の実施形態の再生装置400を示す。再生装置400は、光ディスク100から情報を再生する装置である。
本発明が適用可能な記録媒体の一例として、ブルーレイディスク(BD)や他の規格の光ディスクがあるが、ここではBDに関して説明する。BDには、記録膜の特性に応じて、再生専用型であるBD-ROM,追記記録型・ライトワンス型であるBD-R,書換記録型であるBD-REなどのタイプがあり、本発明は、BDや他の規格の光ディスクにおけるROM(再生専用型),R(追記型・ライトワンス型),RE(書換型)のいずれのタイプの記録媒体にも適用可能である。ブルーレイディスクの主な光学定数と物理フォーマットについては、「ブルーレイディスク読本」(オーム社出版)やブルーレイアソシエーションのホームページ(http://www.blu-raydisc.com/)に掲載されているホワイトペーパに開示されている。
レーザー光を保護層の側から入射して情報が再生及び/又は記録される片面ディスクとすると、記録層を二層以上にする場合、基板と保護層の間には複数の記録層が設けられることになるが、その場合における多層ディスクの一般的な構成例を図7に示す。図示された光ディスクは、(n+1)層の情報記録層502で構成されている(nは0以上の整数)。その構成を具体的に説明すると、光ディスクには、レーザー光505が入射する側の表面から順に、カバー層501、(n+1)枚の情報記録層(Ln~L0層)502、そして基板500が積層されている。また、(n+1)枚の情報記録層502の層間には、光学的緩衝材として働く中間層503が挿入されている。つまり、光入射面から所定の距離を隔てた最も奥側の位置(光源から最も遠い位置)に基準層(L0)を設け、基準層(L0)から光入射面側に層を増やすように記録層を積層(L1,L2,・・・,Ln)している。
ここで、単層ディスクの構成例を図8に、二層ディスクの構成例を図9に、三層ディスクの構成例を図10に、四層ディスクの構成例を図11に示す。前述のように、光照射面から基準層L0までの距離を一定にする場合、図9から図11のいずれにおいても、ディスクの総厚みは略1.2mm(レーベル印刷なども含んだ場合、1.40mm以下にするのが好ましい)、基板500の厚みは略1.1mm、光照射面から基準層L0までの距離は略0.1mmとなる。図8の単層ディスク(図7においてn=0の場合)においては、カバー層5011の厚みは略0.1mm、また、図9の二層ディスク(図7においてn=1の場合)においては、カバー層5012の厚みは略0.075mm、中間層5302の厚みは略0.025mm、また、図10の三層ディスク(図7においてn=2の場合)や図11の四層ディスク(図7においてn=3の場合)においては、カバー層5013、5014の厚みや、中間層5303、5304の厚みは、更に薄くしても良い。
100 × Pw(n)/Pw(n+a) ≧ -0.1238 × D2 - 2.772 × D + 106.56
Pw(n)≦Pw(n+a)
(ここで、nは0以上の整数、aはn+a≧0、かつ、a≠0を満たす整数である)
の関係を有する。
次に、記録密度について、図13、図14、図15および図16を用いて説明する。
また、高記録密度のディスクBにおける波長と開口数とマーク長/スペース長との関係は以下の通りである。
P ≦ λ/2NA
となるまで基準Tが小さくなると、最短マークの空間周波数は、OTFカットオフ周波数を超えることになる。
T = 405/(2x0.85)/4 = 59.558nm
となる(なお、逆に、P > λ/2NA である場合は、最短マークの空間周波数はOTFカットオフ周波数より低い)。
ここで、波長405nm,開口数0.85等のスペックを有するBDにおける1層あたりの具体的な記録容量としては、最短マークの空間周波数がOTFカットオフ周波数付近である場合においては、例えば、略29GB(例えば、29.0GB±0.5GB,あるいは29GB±1GBなど)若しくはそれ以上、又は略30GB(例えば、30.0GB±0.5GB,あるいは30GB±1GBなど)若しくはそれ以上、又は略31GB(例えば、31.0GB±0.5GB,又は31GB±1GBなど)若しくはそれ以上、又は略32GB(例えば、32.0GB±0.5GB,あるいは32GB±1GBなど)若しくはそれ以上、などを想定することが可能である。
100 × Pw(n) / Pw(n+a) ≧ -0.1238 × D2 - 2.772 × D + 106.56
および
Pw(n) ≦ Pw(n+a)
を満たす。
100 × Pw(n) / Pw(n+a) ≧ -0.1238 × D2 - 2.772 × D + 106.56
および
Pw(n) ≦ Pw(n+a)
を満たす。
t0、t1、t2、t3、t4、t5、t6 情報記録層間の基材厚
Pw0、Pw1、Pw2、Pw3 再生パワー
100 記録媒体
400 再生装置
402 光ピックアップ
403 半導体レーザー制御部
404 サーボ処理部
405 信号処理部
406 中央処理部
Claims (7)
- 情報が記録される情報記録層を複数備えた多層情報記録媒体であって、
少なくとも1つの前記情報記録層は、情報を再生するときに用いられる再生パワーが他の情報記録層と異なっており、
各情報記録層間の基材厚は所定の厚み以上である、情報記録媒体。 - 前記基材厚は、収差による光強度減少量が所定以上となる厚みである、請求項1に記載の情報記録媒体。
- 3層以上の情報記録層を備えた情報記録媒体であって、
前記情報記録媒体の読み取り側から最も遠い情報記録層から順に数えてn番目の情報記録層L(n)から情報を再生するときのレーザー光の再生パワーはPw(n)であり(ここで、nは0以上の整数である)、
n+a番目の情報記録層L(n+a)から情報を再生するときのレーザー光の再生パワーはPw(n+a)であり(ここで、aはn+a≧0且つa≠0を満たす整数である)、
前記各情報記録層間の基材厚は、前記再生パワーPw(n)のレーザー光が前記情報記録層L(n+a)に照射されたときの光強度が、前記再生パワーPw(n+a)のレーザー光が情報記録層L(n+a)に照射されたときの光強度以下となる厚みである、情報記録媒体。 - 3層以上の情報記録層を備えた情報記録媒体であって、
前記情報記録媒体の読み取り側から最も遠い情報記録層から順に数えてn番目の情報記録層L(n)から情報を再生するときのレーザー光の再生パワーをPw(n)とし(ここで、nは0以上の整数である)、
n+a番目の情報記録層L(n+a)から情報を再生するときのレーザー光の再生パワーをPw(n+a)とし(ここで、aはn+a≧0且つa≠0を満たす整数である)、
前記情報記録層L(n)と前記情報記録層L(n+a)との間の基材厚をDとしたとき、
100 × Pw(n) / Pw(n+a) ≧ -0.1238 × D2 - 2.772 × D + 106.56
および
Pw(n) ≦ Pw(n+a)
を満たす、情報記録媒体。 - 請求項4に記載の情報記録媒体から情報を再生する再生方法であって、
前記情報記録層L(n)から情報を再生するときに、前記再生パワーPw(n)のレーザー光を前記情報記録層L(n)に照射するステップと、
前記情報記録層L(n+a)から情報を再生するときに、前記再生パワーPw(n+a)のレーザー光を前記情報記録層L(n+a)に照射するステップと、
を含む、再生方法。 - 請求項4に記載の情報記録媒体から情報を再生する再生装置であって、
前記情報記録媒体にレーザー光を照射する照射部を備え、
前記照射部は、前記情報記録層L(n)から情報を再生するときは、前記再生パワーPw(n)のレーザー光を前記情報記録層L(n)に照射し、
前記照射部は、前記情報記録層L(n+a)から情報を再生するときは、前記再生パワーPw(n+a)のレーザー光を前記情報記録層L(n+a)に照射する、再生装置。 - k個の情報記録層(kは3以上の整数)を備える情報記録媒体の製造方法であって、
開口数0.84~0.86の対物レンズを介して、波長400~410nmのレーザー光を用いて情報が再生可能なk個の情報記録層を、厚さ1.1mmの基板上に形成するステップと、
情報記録層と情報記録層との間にk-1個の中間層を形成するステップと、
前記基板側から数えてk番目の情報記録層上に、厚さ0.1mm以下の保護層を形成するステップと、
を含み、
前記情報記録層を形成するステップは、
前記基板側から数えて奇数番目の情報記録層および偶数番目の情報記録層のうちの一方の再生方向が、前記情報記録媒体の外周側から内周側の方向となるように、同心円状またはスパイラル状のトラックを形成するステップと、
前記奇数番目および偶数番目の情報記録層のうちの他方の再生方向が、前記情報記録媒体の内周側から外周側の方向となるように、同心円状またはスパイラル状のトラックを形成するステップと、
を含み、
前記情報記録媒体の読み取り側から最も遠い情報記録層から順に数えてn番目の情報記録層L(n)から情報を再生するときのレーザー光の再生パワーをPw(n)とし(ここで、nは0以上の整数である)、
前記情報記録媒体の読み取り側から最も遠い情報記録層から順に数えてn+a番目の情報記録層L(n+a)から情報を再生するときのレーザー光の再生パワーをPw(n+a)とし(ここで、aはn+a≧0且つa≠0を満たす整数である)、
前記情報記録層L(n)と前記情報記録層L(n+a)との間の基材厚をDとしたとき、
100 × Pw(n) / Pw(n+a) ≧ -0.1238 × D2 - 2.772 × D + 106.56
および
Pw(n) ≦ Pw(n+a)
を満たす、情報記録媒体の製造方法。
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Publication number | Priority date | Publication date | Assignee | Title |
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JP5638127B2 (ja) * | 2011-04-11 | 2014-12-10 | 日立コンシューマエレクトロニクス株式会社 | 多層情報記録媒体,並びにそれを用いた情報再生方法及び情報記録方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004342283A (ja) * | 2002-07-31 | 2004-12-02 | Ricoh Co Ltd | 多層構成型光記録媒体 |
JP2005122862A (ja) | 2003-10-20 | 2005-05-12 | Pioneer Electronic Corp | 多層光記録媒体および光ピックアップ装置 |
JP2006040456A (ja) | 2004-07-29 | 2006-02-09 | Sony Corp | 多層光情報記録媒体 |
Family Cites Families (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5677903A (en) * | 1991-03-25 | 1997-10-14 | U.S. Phillips Corporation | Multi-layer information storage system with improved aberration correction |
US6768710B2 (en) * | 2000-12-18 | 2004-07-27 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium, method for producing the same, and method and apparatus for recording information thereon |
CN1264153C (zh) * | 2001-03-28 | 2006-07-12 | 拜尔公司 | 光记录介质 |
JP2003036561A (ja) | 2001-07-26 | 2003-02-07 | Nec Corp | 光学的情報記録媒体、光学的情報記録再生装置および光学的情報記録再生方法 |
KR100925213B1 (ko) | 2002-06-07 | 2009-11-06 | 엘지전자 주식회사 | 고밀도 멀티 레이어 광디스크와, 그에 따른 광 파워조절방법 |
US20050213467A1 (en) | 2002-12-17 | 2005-09-29 | Yoshihiro Noda | Optical recording medium, and recording/reading method and recording/reading apparatus for optical recording medium |
US7286454B2 (en) | 2003-06-30 | 2007-10-23 | Samsung Electronics Co., Ltd. | Information storage medium |
JP2005122872A (ja) | 2003-09-22 | 2005-05-12 | Ricoh Co Ltd | 2層相変化型情報記録媒体及びその記録再生方法 |
JP4253725B2 (ja) * | 2003-10-31 | 2009-04-15 | 独立行政法人産業技術総合研究所 | データ再生方法およびデータ記録再生装置 |
US7385891B2 (en) * | 2004-03-03 | 2008-06-10 | Samsung Electronics Co., Ltd. | Method, a medium, and an apparatus to record/reproduce data on/from a portion of the medium through which a test beam is passed while determining an optimum power |
JP4412101B2 (ja) * | 2004-08-03 | 2010-02-10 | Tdk株式会社 | 光記録媒体 |
JP4341505B2 (ja) | 2004-08-19 | 2009-10-07 | ソニー株式会社 | 多層光情報記録媒体 |
US7907502B2 (en) * | 2004-11-08 | 2011-03-15 | Panasonic Corporation | Optical information recording medium, its information recording/reproducing method, and information recording/reproducing device |
KR101120025B1 (ko) * | 2005-03-10 | 2012-03-15 | 삼성전자주식회사 | 다층 기록 매체 및 그 제조 방법 |
WO2006132076A1 (ja) * | 2005-06-07 | 2006-12-14 | Matsushita Electric Industrial Co., Ltd. | 情報記録媒体とその製造方法 |
JP4447574B2 (ja) * | 2005-06-30 | 2010-04-07 | シャープ株式会社 | 光ピックアップ、および光記録再生装置 |
JP2007250136A (ja) * | 2006-03-17 | 2007-09-27 | Toshiba Corp | 光ディスク及び光ディスク装置 |
US20080062244A1 (en) * | 2006-09-11 | 2008-03-13 | Hewlett-Packard Development Company Lp | Laser writing |
JP4605148B2 (ja) * | 2006-12-15 | 2011-01-05 | Tdk株式会社 | 多層光記録媒体の光記録方法、光記録装置 |
US20080170485A1 (en) * | 2007-01-15 | 2008-07-17 | Tdk Corporation | Optical recording medium |
JP4792443B2 (ja) * | 2007-09-28 | 2011-10-12 | 株式会社日立製作所 | 光情報再生方法、光情報再生装置及び光情報記録媒体 |
WO2010067556A1 (ja) | 2008-12-11 | 2010-06-17 | パナソニック株式会社 | 情報記録媒体、再生装置および再生方法 |
-
2009
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Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004342283A (ja) * | 2002-07-31 | 2004-12-02 | Ricoh Co Ltd | 多層構成型光記録媒体 |
JP2005122862A (ja) | 2003-10-20 | 2005-05-12 | Pioneer Electronic Corp | 多層光記録媒体および光ピックアップ装置 |
JP2006040456A (ja) | 2004-07-29 | 2006-02-09 | Sony Corp | 多層光情報記録媒体 |
Non-Patent Citations (2)
Title |
---|
"Blu-ray Disc Reader", OHMSHA, LTD. |
See also references of EP2360692A4 |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5638127B2 (ja) * | 2011-04-11 | 2014-12-10 | 日立コンシューマエレクトロニクス株式会社 | 多層情報記録媒体,並びにそれを用いた情報再生方法及び情報記録方法 |
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