Source: http://www.google.com/patents/US8179763?dq=4316055
Timestamp: 2015-07-07 23:18:15
Document Index: 651671159

Matched Legal Cases: ['Application No. 11162905', 'Application No. 11162907', 'Application No. 11162904', 'Application No. 2010', 'Application No. 2006', 'Application No. 07109208', 'Application No. 096']

Patent US8179763 - Optical disc, information recording method, and information reproducing method - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsAccording to one embodiment, a re-recordable write-once optical disc by which recording/reproducing can be properly done with a short-wavelength blue laser is provided. The disc has recording layers on which marks are recorded by the laser power of a modulated short wavelength, with a space formed between...http://www.google.com/patents/US8179763?utm_source=gb-gplus-sharePatent US8179763 - Optical disc, information recording method, and information reproducing methodAdvanced Patent SearchPublication numberUS8179763 B2Publication typeGrantApplication numberUS 11/752,705Publication dateMay 15, 2012Filing dateMay 23, 2007Priority dateMay 31, 2006Also published asCN101083097A, CN101923873A, EP1863026A2, EP1863026A3, EP2343703A1, EP2346034A1, EP2352150A1, US20070281123, US20120195179Publication number11752705, 752705, US 8179763 B2, US 8179763B2, US-B2-8179763, US8179763 B2, US8179763B2InventorsKazuyo Umezawa, Seiji Morita, Koji Takazawa, Hideo Ando, Yasuaki Ootera, Naomasa Nakamura, Naoki MorishitaOriginal AssigneeKabushiki Kaisha ToshibaExport CitationBiBTeX, EndNote, RefManPatent Citations (49), Non-Patent Citations (10), Classifications (12), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetOptical disc, information recording method, and information reproducing method
FIG. 13 is an exemplary view showing an optical reflectance range of each of a High-to-Low (“H-L”) recording film and a Low-to-High (“L-H”) recording film;
Specifically, a specific dye material is used for the recording layer, wherein a change in the volume of or in the surface condition of the recording layer at the recording mark area is to be equal to or less than 10%. Or, a specific material is used for the dye material of the recording layer, said specific material having a property to substantially avoid a chemical change in the recorded layer. More specifically, at least part of an organic dye material to be used for the recording layer may include an azo metal complex whose center metal uses copper Cu or nickel Ni.
When a change in the volume of or in the surface condition of the recording layer at the recording mark area exists, it is liable to occur a distortion in the reproduction signal obtained when repetitive patterns of long marks/spaces (e.g., 11T patterns) are recorded. From this, the difference ([I11Lmax−I11Lmin]) between the maximum and minimum values of a signal level from a space portion is to be 10% of the minimum value (I11min) or less, where the signal is reproduced when long patterns are recorded, and both the mark and space lengths of the long patterns are longer than 1.2*λ/NA (λdenotes the laser wavelength for recording, and NA denotes the numerical aperture).
On transparent resin substrate 101, spiral grooves with the track pitch of 0.4 μm and the depth of 60 nm, for example, are formed (for respective layers L0 and L1). The grooves are wobbled so that address information is recorded on the wobble. Further, recording layers 105 and 107 each including an organic dye are formed on transparent resin substrate 101 so as to fill-up the grooves.
A low light reflectivity may be met when a recording laser light is focused on or tracking over the track before recording of information. Thereafter, the dye is subjected to a resolving reaction by the laser light to reduce the optical absorption rate, so that the light reflectivity at the recording mark portion is enhanced. From this, a so-called “Low-to-High” (or “L to H”) characteristic is obtained wherein the light reflectivity at the recording mark portion formed by irradiating the laser light becomes higher than the light reflectivity obtained before the laser light irradiation.
According to the embodiment, a physical format that can be applied to the L0 and L1 layers on transparent resin substrate 101 and photo polymer (2P resin) 104 may be as follows: Namely, general parameters of a recordable single-sided dual-layer disc are almost the same as those of a single-layer disc, except for the following. That is, the user-available recording capacity is 30 GB, the inner radius of layer 0 (L0 layer) of the data area is 24.6 mm, the inner radius of layer 1 (L1 layer) thereof is 24.7 mm, and the outer radius (of each of layer 0 and layer 1) of the data area is 58.1 mm.
In optical disc 100 of FIG. 1( a), system lead-in area SLA includes a control data section as exemplified by FIG. 1( c). The control data section includes, as a part of physical format information, etc., recording-related parameters such as recording power (peak power), bias power, and the like, for each of L0 and L1.
On the track within data area DA of optical disc 100, as exemplified by FIG. 1( d), mark/space recording is done by the laser with a given recording power (peak power) and bias power. By this mark/space recording, as exemplified by FIG. 1( e), object data (such as VOB) and its management information (VMG) of a high-definition TV broadcasting program, for example, are recorded on the track (of L0 and/or L1) in data area DA.
An azo compound includes an aromatic ring. Not only by applying various structures to the aromatic ring, but by adopting or getting various substituents for the aromatic ring, it is possible to optimize the characteristics of recording, preserving, reproduction stability, etc. As the substituent becomes bulky, there is a tendency to improve the persistence to reproduction light. But at the same time, there is another tendency to lower the recording sensitivity. From this it is proposed to select a suitable substituent with which both characteristics of the persistence and the sensitivity are good. This substituent concerns the solubility of the solvent.
Differing from the recording mechanism of a dye-based information recording medium until now (whose recording laser wavelength is longer than 620 nm), in case of the invention relating to short wavelength laser recording (whose recording wavelength is 405 nm, for instance), the recording mechanism is independent of a physical change in the substrate and/or in the volume of the dye film. During reproducing, the dye is subjected to the irradiation of a feeble laser (weaker than the recording laser). Heat or light of this laser causes a gradual change in the arrangement or orientation of dye molecules in the recording layer, or in the spatial conformation or spatial arrangement of the dye molecules. However, bulky substituents in the dye molecules may disturb that change. In other words, the bulky substituent serves to improve the persistence to reproduction light.
FIG. 2 shows an example of the metal complex portion of an organic dye material for the recording layer. A circular periphery area around center metal M of the azo metal complex shown in FIG. 2 is obtained as coloring area 8. When a laser light beam passes through coloring area 8, local electrons in coloring area 8 resonate to an electric field change of the laser light beam, and absorbs energy of the laser light beam. A value converted to a wavelength of the laser light beam with respect to a frequency of an electric field change at which these local electrons resonate most and easily absorbs the energy is called a maximum absorption wavelength, and is represented by max. As a range of coloring area 8 (resonation range) as shown in FIG. 2 increases, the maximum absorption wavelength λmax is shifted to the long wavelength side. In addition, the localization range of local electrons around the center metal M (how large the center metal M can attract the local electrons to the vicinity of the center) is changed by changing atoms of the center metal M, and the value of the maximum absorption wavelength λmax changes. When a material having a property that the λmax is about 405 nm is selected, an organic material having a sensitivity (optical absorption) at wavelength 405 nm can be obtained.
FIG. 2 shows a specific structural formula of the specific contents “(A3) azo metal complex+Cu” of the constituent elements of the information storage medium. A circular periphery area around center metal M of the azo metal complex shown in FIG. 2 is obtained as coloring area 8. When laser light beam 7 passes through coloring area 8, local electrons in coloring area 8 resonate to an electric field change of laser light beam 7, and absorbs energy of laser light beam 7. A value converted to a wavelength of the laser light beam with respect to a frequency of an electric field change at which these local electrons resonate most and easily absorbs the energy is called a maximum absorption wavelength, and is represented by λmax. As a range of coloring area 8 (resonation range) as shown in FIG. 2 increases, the maximum absorption wavelength λmax is shifted to the long wavelength side. In addition, in FIG. 2, the localization range of local electrons around the center metal M (how large the center metal M can attract the local electrons to the vicinity of the center) is changed by changing atoms of center metal M, and the value of the maximum absorption wavelength λmax changes.
Although it can be predicted that the light absorption spectra of the organic dye recording material in the case where there exists only one coloring area 8 which is absolute 0 degree at a temperature and high in purity draws narrow linear spectra in close to a maximum absorption wavelength λmax, the light absorption spectra of a general organic recording material including impurities at a normal temperature, and further, including a plurality of light absorption areas exhibit a wide light absorption characteristic with respect to a wavelength of a light beam around the maximum absorption wavelength max. FIG. 5 shows an example of light absorption spectra of an organic dye recording material used for a current DVD-R disc. In FIG. 5, a wavelength of a light beam to be irradiated with respect to an organic dye recording film formed by coating an organic dye recording material is taken on a horizontal axis, and absorbance obtained when an organic dye recording film is irradiated with a light beam having a respective wavelength is taken on a vertical axis. The absorbance used here is a value obtained by entering a laser light beam having incident intensity Io from the side of transparent substrate 2-2 with respect to a state in which a recordable or write-once type information storage medium has been completed (or alternatively, a state in which recording layer 3-2 is merely formed on transparent substrate 2-2 (a state that precedes forming of an optical reflection or reflective layer)), and then, measuring reflected laser light intensity Ir (light intensity It of the laser light beam transmitted from the side of recording layer 3-2). The absorbance Ar (At) is represented by:
Ar≡−log 10(Ir/Io) (A-1)
Ar≡−log 10(It/Io) (A-2)
Unless otherwise specified, although a description will be given assuming that the absorbance denotes absorbance Ar of a reflection shape expressed by formula (A-1), it is possible to define absorbance At of a transmission shape expressed by formula (A-2) without being limited thereto in the embodiment. In the embodiment shown in FIG. 5, there exist a plurality of light absorption areas, each of which includes coloring area 8, and thus, there exist a plurality of positions at which the absorbance becomes maximal. In this case, there exist a plurality of maximum absorption wavelengths λmax when the absorbance takes a maximum value. A wavelength of the recording laser light in the current DVD-R disc is set to 650 nm. In the case where there exist a plurality of the maximum absorption wavelengths λmax in the embodiment, a value of the maximum absorption wavelength λmax which is the closest to the wavelength of the recording laser light beam becomes important. Therefore, only in the description of the embodiment, the value of the maximum absorption wavelength λmax set at a position which is the closest to the wavelength of the recording laser light beam is defined as “λmax write”; and is discriminated from other λmax (λmax 0).
2-2) Difference of light reflection or reflective layer shape in pre-pit/pre-groove area . . . Influence on optical reflection or reflective layer shape (difference between spin-coating and sputtering deposition) and reproduction signal
FIG. 6B shows a general recording film sectional shape of a current DVD-R disc which is a conventional technique as a recording film in the case where an organic dye recording film is used. In this case, as a method for forming the recording film 3-2, there is used a method called spin coating (or spinner coating) which is completely different from that shown in FIG. 6A. The spin coating used here denotes a method for dissolving in an organic solvent an organic dye recording material which forms recording layer 3-2; applying a coating onto transparent substrate 2-2; followed by rotating transparent substrate 2-2 at a high speed to spread a coating agent to the outer periphery side of transparent substrate 2-2 by a centrifugal force; and gasifying the organic solvent, thereby forming the recording layer 3-2. Using this method, a process for coating the organic solvent is used, and thus, a surface of recording layer 3-2 (an interface with light reflection or reflective layer 2-2) is easily flattened. As a result, the sectional shape on the interface between light reflection or reflective layer 2-2 and recording layer 3-2 is obtained as a shape which is different from the shape of the surface of transparent substrate 2-2 (an interface between transparent substrate 2-2 and recording layer 3-2). For example, in a pre-groove area in which the sectional shape of the surface of transparent substrate 2-2 (an interface between transparent substrate 2-2 and recording layer 3-2) is rectangular or trapezoidal, the sectional shape on the interface between light reflection or reflective layer 2-2 and recording layer 3-2 is formed in a substantially V-shaped groove shape. In a pre-pit area, the above sectional shape is formed in a substantially conical side surface shape. Further, at the time of spin coating, an organic solvent is easily collected at a recessed portion, and thus, the thickness Dg of recording layer 3-2 in the pre-pit area or pre-groove area 10 (i.e., a distance from a bottom surface of the pre-pit area or pre-groove area to a position at which an interface relevant to light reflection or reflective layer 2-2 becomes the lowest) is larger than the thickness Dl in land area 12 (Dg>Dl). As a result, an amount of irregularities on an interface between transparent substrate 2-2 and recording area 3-2 in the pre-pit area or pre-groove area 10 becomes materially smaller than an amount of irregularities on transparent substrate 2-2 and recording layer 3-2.
In addition, in a DVD-R disc, specific information such as address information is recorded in a small irregular (pit) shape in a land area, and thus, width Wl of the land area 12 is larger than width Wg of the pre-pit area or pre-groove area 10 (Wg>Wl).
Chapter 3: Description of Characteristics of Organic Dye Recording Film in the Embodiment
As has been described in “2-1) Difference in recording principle/recording film structure and difference in basic concept relating to generation of reproducing signal”, a general principle of recording of a current DVD-R and CD-R, which is a recordable (write-once type) information storage medium using a conventional organic dye material includes “local plastic deformation of transparent substrate 2-2” or “local thermal decomposition or gasification in recording layer 3-2”. FIGS. 7A and 7B show a plastic deformation state of a specific transparent substrate 2-2 at a position of a recording mark 9 in a write-once type information storage medium using a conventional organic dye material. There exist two types of typical plastic deformation states. There are two cases, i.e., a case in which, as shown in FIG. 7A, a depth of bottom surface 14 of a pre-groove area at the position of recording mark 9 (an amount of step relevant to adjacent land area 12) is different from a depth of a bottom surface of pre-groove area 11 in an unrecorded area (in the example shown in FIG. 7A, the depth of bottom surface 14 in the pre-groove area at the position of recording mark 9 is shallower than that in the unrecorded area); and a case in which, as shown in FIG. 7B, bottom surface 14 in a pre-groove area at the position of recording mark 9 is distorted and is slightly curved (the flatness of bottom surface 14 is distorted: In the example shown in FIG. 7B, bottom surface 14 in the pre-groove area at the position of recording mark 9 is slightly curved toward the lower side). Both of these cases are featured in that a plastic deformation range of transparent substrate 2-2 at the position of recording mark 9 covers a wide range. In the current DVD-R disc which is a conventional technique, a track pitch is 0.74 μm, and a channel bit length is 0.133 μm. In the case of a large value of this degree, even if the plastic deformation range of transparent substrate 2-2 at the position of recording mark 9 covers a wide range, comparatively stable recording and reproducing processes can be carried out.
However, if the track pitch is narrower than 0.74 μm described above, the plastic deformation range of transparent substrate 2-2 at the position of recording mark 9 covers a wide range, and thus, the adjacent tracks are adversely affected with “cross-write” or “cross-erase”. In the “cross-write” the recording mark is widened to the adjacent tracks, and in the “cross-erase” the recording mark of the existing adjacent track is substantially erased (or cannot be reproduced) due to overwriting. In addition, in a direction (circumferential direction) along the tracks, if the channel bit length is narrower than 0.133 μm, there occurs a problem that inter-code interference appears; an error rate at the time of reproduction significantly increases; and the reliability of reproduction is lowered.
3-2) Description of Basic Characteristics Common to Organic Dye Recording Film in the Embodiment
3-2-A] Range Requiring Application of Technique According to the Embodiment
1) Condition of Thickness Dg of Recording Layer 3-2 When an attempt is made to carry out thermal analysis in order to theoretically identify a lower limit value of an allowable channel bit length or a lower limit value of allowable track pitch, a range of the thickness Dg of recording layer 3-2 which can be substantially thermally analyzed becomes important. In a conventional recordable (write-once type) information storage medium (CD-R or DVD-R) including plastic deformation of transparent substrate 2-2 as shown in FIGS. 7A and 7B, with respect to a change of light reflection amount in the case where an information reproduction focusing spot is provided in recording mark 8 and in the case where the spot is in an unrecorded area of recording layer 3-2, the largest factor is “an interference effect due to a difference in optical distance in recording mark 9 and in unrecorded area”. In addition, a difference in its optical difference is mainly caused by “a change of the thickness Dg of physical recording layer 3-2 due to plastic deformation of transparent substrate 2-2 (Dg: a physical distance from an interface between transparent substrate 2-2 and recording layer 3-2 to an interface between recording layer 3-2 and light reflection or reflective layer 4-2)” and “a change in refractive index n32 of recording layer 3-2 in recording mark 9”. Therefore, in order to obtain a sufficient reproduction signal (change of light reflection amount) between the recording mark 9 and the unrecorded area, when a wavelength in vacuum of laser light beam is defined as λ, it is demanded that the value of thickness Dg of recording layer 3-2 in the unrecorded area has a size to some extent as compared with λ/n32. If not, a difference (phase difference) in optical distance between the recording mark 9 and the unrecorded area does not appear, and light interference effect becomes small. In practice, a minimum condition:
Dg≧λ/8n32 (1)
shall be met, and desirably, a condition that:
Dg≧λ/4n32 (2)
At a time point of current discussion, the vicinity of λ=405 nm is assumed. A value of refractive index n32 of an organic dye recording material at 405 nm ranges from 1.3 to 2.0. Therefore, as a result of substituting n32=2.0 in formula (1), it is conditionally mandatory that the value of thickness Dg of recording layer 3-2 is:
Dg≧25 nm (3)
From another point of view as well, the range of thickness Dg can be specified. In the case of a phase change recording film shown in FIG. 6A, when a refractive index of the transparent substrate is n21, the step amount between a pre-pit area and a land area is λ/(8n21) when the largest track shift detection signal is obtained by using a push-pull technique. However, in the case of an organic dye recording film shown in FIG. 6B, as described previously, the shape on an interface between recording layer 3-2 and light reflection or reflective layer 4-2 becomes blunt, and the step amount becomes small. Thus, it is demanded to increase the step amount between the pre-pit area and the land area on transparent substrate 2-2 more significantly than λ/(8n22). When polycarbonate is used as a material for transparent substrate 2-2, for example, the refractive index at 405 nm is n22≅1.62. From this, it is demanded to increase a step amount between the pre-pit area and the land area more significantly than 31 nm. In the case of using a spin coating technique, if the thickness Dg of recording layer 3-2 in the pre-groove area is greater than the step amount between the pre-pit area and the land area on transparent substrate 2-2, there is a risk that the thickness D1 of recording layer 3-2 in land area 12 disappears. Therefore, from the above described discussion result, it is demanded to meet a condition that:
Dg≧31 nm (4)
The condition for formula (4) is also a condition, which should be met in the embodiment in which plastic deformation of transparent substrate 2-2 does not occur. Although conditions for the lower limit values have been shown in formulas (3) and (4), the value Dg≅60 nm obtained by substituting n32=1.8 for an equal sign portion in formula (2) is utilized as the thickness Dg of recording layer 3-2 used for thermal analysis.
Then, assuming polycarbonate used as a standard material of transparent substrate 2-2, 150� C. which is a glass transition temperature of polycarbonate is set as an estimate value of a thermal deformation temperature at the side of transparent substrate 2-2. For discussion using thermal analysis, a value of k32=0.1 to 0.2 is assumed as a value of an absorption coefficient of organic dye recording film 3-2 at 405 nm. Further, for the case wherein NA=60 as the condition of a conventional DVD-R format and NA=0.65 as the H format, discussion has been made with respect to the NA value of a focusing objective lens and the incident light intensity distribution when the light passes through the objective lens.
In the foregoing, a description has been principally given with respect to discussion using thermal analysis in the case where thermal deformation of transparent substrate 2-2 occurs. There also exists a case in which plastic deformation of transparent substrate 2-2 is very small as another principle of recording (mechanism of forming the recording mark 9) in a conventional write-once type information storage medium (CD-R or DVD-R) and thermal deformation or gasification (evaporation) of the organic dye recording material in recording layer 3-2 mainly occurs. Thus, an additional description will be given with respect to such a case. Although the gasification (evaporation) temperature of the organic dye recording material is different depending on the type of the organic dye material, in general, the temperature ranges 220� C. to 370� C., and a thermal decomposition temperature is lower than this range. Although a glass transition temperature 150� C. of a polycarbonate resin has been presumed as an arrival temperature at the time of substrate deformation in the above discussion, a temperature difference between 150� C. and 220� C. is small, and, when transparent substrate 2-2 reaches 150� C., the inside of recording layer 3-2 may exceed 220� C. Therefore, although there exists an exception depending on the type of the organic recording material, even in the case where plastic deformation of transparent substrate 2-2 is very small and thermal decomposition or gasification (evaporation) of the organic dye recording material in the recording layer mainly occurs, there is obtained a result which is substantially identical to the above discussion result.
When recording layer 3-2 is exposed at recording power, energy is absorbed in recording layer 3-2, and a high temperature is obtained. In a conventional write-once type information storage medium (CD-R or DVD-R), it is demanded to absorb energy in recording layer 3-2 until transparent substrate 3-2 has reached a thermal deformation temperature. A temperature at which a structural change of the organic dye recording material occurs in recording layer 3-2 and a value of a refractive index n32 or an absorption coefficient k32 starts its change is much lower than an arrival temperature for transparent substrate 2-2 to start thermal deformation. Therefore, the value of refractive index n32 or absorption coefficient k32 changes in a comparatively wide range in recording layer 3-2 at the periphery of recording mark 9, which is thermal deformed at the side of transparent substrate 2-2, and this change seems to cause “cross-write” or “cross-erase” for the adjacent tracks. It is possible to set the lower limit value of track pitch in which “cross-write” or “cross-erase” does not occur with the width of an area which reaches a temperature that changes the refractive index n32 or absorption coefficient k32 in recording layer 3-2 when transparent substrate 2-2 exceeds a thermal deformation temperature. From the above point of view, it is considered that “cross-write” or “cross-erase” may occur in location in which the track pitch is equal to or smaller than 500 nm. Further, in consideration of an effect of warping or inclination of an information storage medium or a change of recording power (recording power margin), it can be concluded difficult to set the track pitch to 600 nm or less in the conventional write-once type information storage medium (CD-R or DVD-R) in which energy is absorbed in recording layer 3-2 until transparent substrate 2-2 has reached a thermal deformation temperature. As described above, even if the NA value is changed from 0.60, 0.65, and then, to 0.85, substantially similar tendency is shown because the gradient of the temperature distribution in the peripheral recording layer 3-2 when transparent substrate 2-2 has reached a thermal deformation temperature at a center part is comparatively gentle, and the thermal spread range is wide. In the case where plastic deformation of transparent substrate 2-2 is very small and thermal decomposition or gasification (evaporation) of the organic dye recording material in recording layer 3-2 mainly occurs as another principle of recording (mechanism of forming the recording mark 9) in the conventional write-once type information storage medium (CD-R or DVD-R), as has been described in the section “(2) Condition for lower limit value of channel bit”, the value of track pitch at which “cross-write” or “cross-erase” starts is obtained as a substantially analogous result. For the above described reason, advantageous effect is attained by using a novel principle of recording shown in the embodiment when the track pitch is set to 600 nm (500 nm) or lower.
As described above, in the case where plastic deformation of transparent substrate 2-2 is very small and thermal decomposition or gasification (evaporation) of the organic dye recording material in recording layer 3-2 mainly occurs as another principle of recording (mechanism of forming the recording mark 9) in the conventional write-once type information storage medium (CD-R or DVD-R), there occurs a problem that a channel bit length or track pitches cannot be narrowed because the inside of recording layer 3-2 or a surface of transparent substrate 2-2 reaches a high temperature at the time of forming the recording mark 9. In order to solve the above described problem, the embodiment is featured in “inventive organic dye material” in which “a local optical characteristic change in recording layer 3-2, which occurs at a comparatively low temperature, is a principle of recording” and “setting environment (recording film structure or shape) in which the above principle of recording easily occurs without causing a substrate deformation and gasification (evaporation) in recording layer 3-2. Specific characteristics of the embodiment can be listed below.
α] Optical characteristic changing method inside of recording layer 3-2
Chromogenic characteristic change
Change of light absorption sectional area due to qualitative change of coloring area 8 (FIG. 2) or change of molar molecule light absorption coefficient Coloring area 8 is partially destroyed or the size of coloring area 8 changes, whereby a substantial light absorption sectional area changes. In this manner, an amplitude (absorbance) at a position of max write changes in recording mark 9 while a profile (characteristics) of light absorption spectra (FIG. 5) itself is maintained.
Change of electronic structure (electron orbit) relevant to electrons which contribute to a chromogenic phenomenon
Change of light absorption spectra (FIG. 5) based on discoloring action due to cutting of local electron orbit (dissociation of local molecular bonding) or change of dimensions or structure of coloring area 8 (FIG. 2) Intra-molecular (inter-molecular) change of orientation or array
Optical characteristic change based on orientation change in azo metal complex shown in FIG. 2, for example Molecular structure change in molecule
For example, discussion is made with respect to an organic dye material which causes either of dissociation between anion portion and cation portion, thermal decomposition of either of anion portion and cation portion, and a tar phenomenon that a molecular structure itself is destroyed, and carbon atoms are precipitated (denaturing to black coal tar). As a result, the refractive index n32 and/or absorption coefficient k32 in recording mark 9 is changed with respect to an unrecorded area, enabling optical reproduction. β] Setting recording film structure or shape, making it easy to stably cause an optical characteristic change of [α] above:
The specific contents relating to this technique will be described in detail in the section “3-2-C) Ideal recording film structure which makes it easy to cause a principle of recording shown in the embodiment” and subsequent. γ] Recording power is reduced in order to form recording mark in a state in which inside of recording layer or transparent substrate surface is comparatively low at temperature
The optical characteristic change shown in [α] above occurs at a temperature lower than a deformation temperature of transparent substrate 2-2 or a gasification (evaporation) temperature in recording layer 3-2. Thus, the exposure amount (recording power) at the time of recording is reduced to prevent the deformation temperature from being exceeded on the surface of transparent substrate 2-2 or the gasification (evaporation) temperature from being exceeded in recording layer 3-2. The contents will be described later in detail in the section “3-3) Recording characteristics common to organic dye recording layer in the embodiment”. In addition, in contrast, it becomes possible to determine whether or not the optical characteristic change shown in [α] above occurs by checking a value of the optimal power at the time of recording. δ] Electron structure in a coloring area is stabilized, and structural decomposition relevant to ultraviolet ray or reproduction light irradiation is hardly generated
When ultraviolet ray is irradiated to recording layer 3-2 or reproduction light is irradiated to recording layer 3-2 at the time of reproduction, a temperature size in recording layer 3-2 occurs. There is a demand for an apparently contradictory performance that characteristic degradation relevant to such a temperature rise is prevented and recording is carried out at a temperature lower than a substrate deformation temperature or a gasification (evaporation) temperature in recording layer 3-2. In the embodiment, the above described apparently contradictory performance is satisfied by “stabilizing an electron structure in a coloring area”. The specific technical contents may be described in “Chapter 4 Specific Description of Embodiments of Organic Dye Recording Film in the embodiment”. ε] Reliability of reproduction information is improved for a case in which reproduction signal degradation due to ultraviolet ray or reproduction light irradiation occurs
In the embodiment, although a technical contrivance is made for “stabilizing an electron structure in a coloring area”, the reliability of recording mark 9 formed by a principle of recording shown in the embodiment may be principally lowered as compared with a local cavity in recording layer 3-2 generated due to plastic deformation or gasification (evaporation) of the surface of transparent substrate 2-2. As countermeasures against it, in the embodiment, advantageous effect that the high density and the reliability of recording information are achieved at the same time in combination with strong error correction capability (novel ECC block structure), as may be described in “Chapter 7: Description of H Format” and “Chapter 8: Description of B Format”. Further, in the embodiment, PRML (Partial Response Maximum Likelihood) technique is employed in a reproduction method, as may be described in the section “4-2 Description of reproducing circuit in the embodiment”. The high density and the reliability of recording information are achieved at the same time in combination with an error correction technique at the time of the ML demodulation. 5-2) Characteristics of light absorption spectra relating to “L-H” recording film in the embodiment . . . . Setting condition for the value of maximum absorption wavelength max write and Ah405
As described in “3-4) Description of characteristics relating to “H-L” recording film in the embodiment, the relative absorbance in an unrecorded area is basically low in the “H-L” recording film, and thus, when reproduction light is irradiated at the time of reproduction, there occurs a little optical characteristic change generated by absorbing energy of the reproduction light. Even if an optical characteristic change (update of recording action) occurs after the energy of the reproduction light is absorbed in a recording mark having high absorbance, a light reflection factor from the recording mark is lowered. Thus, reproduction signal processing is less affected because such a change effects on a direction in which an amplitude (I11≡I11H−I11L) of the reproduction signal increases.
In contrast, the “L-H” recording film has optical characteristics that “a light reflection factor of an unrecorded portion is lower than that in a recording mark”. This means that the absorbance of the unrecorded portion is higher than that in the recording mark. Thus, in the “L-H” recording film, signal degradation at the time of reproduction is likely to occur as compared with the “H-L” recording film.
As described in “3-2-B] Basic characteristics common to organic dye recording material in the invention”, there is a demand for improving reliability of reproduction information in the case where reproduction signal degradation has occurred due to ε] ultraviolet ray or reproduction light irradiation”.
As a result of examining the characteristics of an organic dye recording material in detail, it is found that a mechanism of absorbing the energy of reproduction light to cause an optical characteristic change is substantially analogous to that of an optical characteristic change due to ultraviolet ray irradiation. As a result, if there is provided a structure of improving durability relevant to ultraviolet ray irradiation in an unrecorded area, signal degradation at the time of reproduction hardly occurs. Thus, the embodiment is featured in that, in the “L-H” recording film, a value of (max write (maximum absorption wavelength which is the closest to wavelength of recording light) is longer than a wavelength of recording light or reproduction light (close to 405 nm). In this manner, the absorbance relevant to the ultraviolet ray can be reduced, and the durability relevant to ultraviolet ray irradiation can be significantly improved. As is evident from FIG. 9, a difference in absorbance between the recorded portion and the unrecorded portion in the vicinity of max write is small,
and a degree of reproduction signal modulation (signal amplitude) is reduced where the light with a wavelength in the vicinity of λmax write is used for reproduction. In view of a wavelength change of a semiconductor laser light source, it is advisable that a sufficiently large degree of reproduction signal modulation (signal amplitude) be taken in the range of 355 nm to 455 nm. Therefore, in the embodiment, the design of recording film 3-2 is made so that the wavelength of λmax write exists out of the range of 355 nm to 455 nm (i.e., at a longer wavelength than 455 nm).
FIG. 8 shows an example of light absorption spectra in the “L-H” recording film in the embodiment. As described in “5-1) Description of feature relating to “L-H” recording film, lower limit value β of a light reflection factor at a non-recording portion (“L” section) of the “L-H” recording film is set to 18%, and upper limit value γ is set to 32% in the embodiment. From 1−0.32=0.68, in order to meet the above condition, it is possible to intuitively understand that value Al405 of the absorbance in an unrecorded area at 405 nm should meet:
Al405≧68% (36)
Although the light reflection factor at 405 nm of light reflection or reflective layer 4-2 is slightly lowered than 100%, it is assumed that the factor is almost close to 100% for the sake of simplification. According to this assumption, the light reflection factor when absorbance Al=0 is almost 100%. In FIG. 8, the light reflection factor of the whole recording film at the wavelength of λmax write is designated by Rλmax write. At this time, assuming that the light reflection factor is zero (Rλmax write≅0), formula (36) is derived. However, in actuality, the factor is not set to “0”, and thus, it is demanded to derive a severer formula. A severe conditional formula for setting the upper light value γ of the light reflection factor of the non-recording portion (“L” portion) of the “L-H” recording film to 32% is given by:
1−Al405�(1−Rλmax write)≦0.32 (37)
In a conventional write-once type information storage medium, only the “H-L” recording film is used, and there is no accumulation of information relating to the “L-H” recording film. However, in the case of using the embodiment described in “5-3) Anion portion: azo metal complex+cation portion: dye”, the severest condition which meets formula (37) is obtained as:
Al405≧80% (38)
In the case of using an organic dye recording material described later in the embodiment, when an optical design of a recording film is made including a margin such as a characteristic variation at the time of manufacture or a thickness change of recording layer 3-2, it is found that a minimum condition, which meet the reflection factor described in the section “Description of feature relating to “L-H” recording film” in the embodiment:
Al405≧40% (39)
may be satisfied. Further, by satisfying either of:
Al355≧40% (40)
Al455≧40% (41)
FIG. 9 shows a light absorption spectrum change after recorded in the “L-H” recording film according to the embodiment. It is considered that the value of maximum absorption wavelength Imax in the recording mark deviates from wavelength of max write, and an inter-molecular array change (for example, an array change between azo metal complexes) occurs. Further, it is considered that a discoloring action (cutting of local electron orbit (or local molecular link dissociation)) occurs in parallel to a fact that both of the absorbance in location of λlmax and the absorbance Al405 at 405 nm are lowered and the light absorption spectra spreads itself.
In the “L-H” recording film according to the embodiment as well, by meeting each of formulas (20), (21), (22), and (23), the same signal processor circuit is made available for both of the “L-H” recording film and the “H-L” recording film, thereby promoting simplification and cost reduction of the signal processor circuit. In formula (20), when:
I11/I11H≡(I11H−I11L)/I11H≧0.4 (42)
I11H≧I11L/0.6 (43)
is obtained. As described previously, in the embodiment, lower limit value β of the light reflection factor of an unrecorded portion (“L” portion) of the “L-H” recording film is set to 18%, and this value corresponds to I11L. Further, conceptually, the above value corresponds to:
I11H≅1−Ah405�(1−Rλmax write) (44).
Thus, from formulas (43) and (44), the following formula is established:
1−Ah405�(1−Rλmax write)≧0.18/0.6 (45)
When 1−Rλmax write≅0, formula (45) may be obtained as:
Ah405≦0.7 (46)
In comparison between the above formulas (46) and (36), it is found that the values of Al405 and Ah405 may be seemingly set in the vicinity of 68% to 70% as values of absorbance. Further, in view of a case in which the value of Al405 is obtained in the range of formula (39) and performance stability of a signal processor circuit, a sever condition may be obtained as:
Ah405≦0.4 (47)
If possible, it is advisable to meet;
Ah405≦0.3 (48)
An evaluation disc of recordable dual-layered optical disc 100 according to one embodiment can be made as follows. More specifically, on transparent resin substrate 101, a 1.2 wt % TFP solution of an organic dye is applied by spin coating to form L0 recording layer 105. The thickness of the dye after application from the bottom of the groove is set to be 60 nm. Reflecting film 106 of an Ag alloy with 25 nm thick is laminated or stacked on the dye-coated substrate by sputtering, and intermediate layer 104 of 2P (photo polymer) resin with 25 μm thickness is spin-coated. A separately prepared polycarbonate stamper is placed thereon to transfer the groove shape, and the stamper is removed. On the 2P resin intermediate layer 104 thus prepared, a 1.2 wt % TFP solution of an organic dye is applied by spin coating to form L1 recording layer 107. Reflection or reflective film 108 of an Ag alloy is laminated or stacked thereon with a thickness of 100 nm by sputtering, and pasted with 0.59 mm thick transparent resin substrate 102 by using UV hardening resin 103.
Explanation on Recording Conditions (Information of Write Strategy)
Optimum recording conditions (information of Write Strategy) can be determined with an apparatus (disc drive) by which a test writing has been done at a drive test zone according to the respective parameter values as mentioned above.
As data of the recording signal, repetitive patterns of 11T mark and 11T space are also used. The physical format existing in the recording layers (L0, L1) on transparent resin substrate 101 and photo polymer resin 104 used in the following examples is explained with reference to FIGS. 26-34 Example 1
Optical disc 100 is prepared using a dye corresponding to the chemical formula of FIG. 4. Information recording is made on this disc using random data. Error rate SbER of the L0 layer is measured. The obtained result shows a good value of 5.4 e-6 which is sufficiently lower that the target value 5.0 e-5 (even though this value may be a higher hurdle than a practical level). When the repetitive patterns of 11T mark and 11T space are recorded and reproduced, almost no waveform distortion is seen. The difference ([I11Lmax−I11Lmin]/I11Lmin) between the maximum and minimum values of I11L, which is a space level obtained when the 11T space is reproduced, is 2%. Here, the 11T mark length is sufficiently long as 1.12 μm, and 1.2*Na/λ is 0.74 μm. Using IR, MS, and NMR, analyses are made for the dye before recording and after recording, but no difference is found between the before and after recordings.
An optical disc is prepared using a dye corresponding to the chemical formula of FIG. 3, and information recording is made thereon. The resultant error rate SbER of the L0 layer is 6.3 e-4 which is larger than the target value 5.0 e-5. This value may cause a difficulty in information reading by a disc drive. When the repetitive patterns of 11T mark and 11T space are recorded and reproduced, a large waveform distortion is seen, and the difference ([I11Lmax−I11Lmin]/I11Lmin) between the maximum and minimum values of space level I11L is 14%.
From the above result and the “Relation between SbER and Change Amount of I11L” shown in FIG. 23, it is found that a barometer or an index for reducing the invention to practice may be based on a selection of dye material which ensures 10% or less of the difference ([I11Lmax−I11Lmin]/I11Lmin) between the maximum and minimum values of I11L.
A DVD-RAM disc, an existing rewritable information storage medium, also uses a phase-change recording film and shifts the recording start and end positions at random to increase the number of rewrites. The maximum amount of shift in making a random shift on an existing DVD-RAM disc is set to eight data bytes. The channel bit length (of modulated data recorded on the disc) in an existing DVD-RAM disc is set to 0.143 μm on average. In the rewritable information storage medium of the embodiment, the average length of a channel bit is:
(0.087+0.093)�2=0.090 μm (6)
When the length of the physical shift range is adapted to the existing DVD-RAM disc, the required minimum length as the random shift range in the embodiment is calculated using the above value as follows:
8 bytes�(0.143 μm+0.090 μm)=12.7 byte (7)
In the embodiment, to facilitate the reproduction signal detecting process, the unit of the amount of random shift is adapted to a “channel bit” after modulation. In the embodiment, since ETM modulation (Eight to Twelve modulation) that converts 8 bits into 12 bits is used, the amount of random shift is expressed using a mathematical formula with a date byte as a reference:
Jm/12 data bytes (8)
It follows from equation (7) that:
12.7�12=152.4 (9)
Therefore, the values Jm can take are from 0 to 152. For the above reasons, in the range satisfying equation (9), the length of the random shift range agrees with the existing DVD-RAM disc, which assures the same number of rewrites as that of the existing DVD-RAM disc. In the embodiment, to secure the number of rewrites larger than that of the existing DVD-RAM disc, a small margin is allowed for the value of equation (7) as follows:
The length of the random shift range is set to 14 data bytes (10)
Substituting the value of equation (10) into equation (8) gives 14�12=168. Therefore, it follows that:
Values Jm can take from 0 to 167 (11)
As described above, the amount of random shift is set to a larger range than Jm/12 (0≦Jm≦154), thereby satisfying equation (9) and causing the length of the physical range for the amount of random shift to agree with the existing DVD-RAM, which produces the effect of assuring the same number of repeated recordings as that of the existing DVD-RAM.
In this embodiment, as shown in FIG. 11, the actual start point position serving as a reference of position setting is set so as to coincide with the position of the wobble amplitude “0” (the center of wobble). However, since the wobble position detecting accuracy is low, the embodiment, as written as “�1 max” in FIG. 11, permits the actual start point position to have up to
a shift of �1 data byte (12)
In FIGS. 10 and 11, the amount of random shift in data segment 530 is set to Jm (as described above, the amount of random shift is the same in all of data segments 529 in recording cluster 540). Thereafter, the amount of random shift in data segment 531 in which additional recording is done is set to Jm+1. A value Jm in equation (11) and Jm+1 can take is, for example, the intermediate value: Jm=Jm+1=84. When the position accuracy of the actual start point is sufficiently high, the starting position of extended guard field 528 coincides with the starting position of VFO area 522 as shown in FIG. 10.
In contrast, when data segment 530 is recorded in the rearmost position and data segment 531 to be rewritten or additionally recorded later is recorded in the very front position, the start position of VFO area 522 may go into buffer area 537 by up to 15 data bytes because of equations (10) and (12). In extra area 534 just in front of buffer area 537, specific important information is recorded. Therefore, in the embodiment, the following is to be met:
the length of buffer area 537 has to be 15 data bytes or more (13)
If a gap occurs between extended guard area 528 and VFO area 522 as a result of a random shift, when a single-sided dual-recording-layer structure is used, interlayer crosstalk is caused by the gap during reproduction. To overcome this problem, extended guard field 528 and VFO area 522 are caused to always partially overlap with each other even when a random shift is made, thereby preventing a gap from occurring. Therefore, in the embodiment, from equation (13), the length of extended guard field 528 is to be set to 15 data bytes or more. Since subsequent VFO 522 is made as long as 71 data bytes, even if the overlapping area of extended guard field 528 and VFO area 522 becomes a little wider, this has no adverse effect in reproducing a signal (because the time demanded to synchronize the reproduction reference clock in unoverlapped VFO area 522 is secured sufficiently). For this reason, extended guard field 528 can be set to a larger value than 15 data bytes. As explained above, there may be occasions when a wobble slip will occur in continuous recording and the recording position will shift by one wobble period. As seen from equation (5), a wobble period corresponds to 7.75 (about 8) data bytes. Thus, taking this into account, equation (13) is modified as follows in the embodiment:
The length of extended guard field 528 is set to (15+8)=23 data bytes or more (14)
Use of both of a “H-L” (High-to-Low) recording film and a “L-H” (Low-to-High) recording film is permitted in the embodiment. FIG. 13 shows the reflectivity ranges of a “H-L” recording film and a “L-H” recording film determined in the embodiment. This embodiment is characterized in that the lower limit of reflectivity at an unrecorded part of the “H-L” recording film is set higher than the upper limit of reflectivity at an unrecorded part of the “L-H” recording film. When the information storage medium is installed in the information recording and reproducing apparatus or information reproducing apparatus, slice level detecting section 132 or PR equalizing circuit 130 (not shown) can measure the reflectivity of an unrecorded part and determine whether the film is a “H-L” recording film or a “L-H” recording film, which makes it very easy to determine the type of recording film. As a result of forming and measuring “H-L” recording films and “L-H” recording films by changing many manufacturing conditions, it is found that, when the reflectivity a between the lower limit of reflectivity at an unrecorded part of the “H-L” recording film and the upper limit of reflectivity at an unrecorded part of the “L-H” recording film is set to 36%, the productivity of the recording film is high and the cost of the recording medium is easy to reduce. When reflectivity range 801 of an unrecorded part (“L” part) of the “L-H” recording film is caused to coincide with reflectivity range 803 of the single-sided dual-layer of a read-only information storage medium and reflectivity range 802 of an unrecorded part (“H” part) of the “H-L” recording film is caused to coincide with reflectivity range 804 of the single-sided single layer of a read-only information storage medium, the interchangeability or compatibility with the read-only information storage medium and a recordable information storage medium is good and the reproducing circuit of a reproduction-only apparatus and that of an information recording and reproducing apparatus can be shared, which enables the information reproducing apparatus to be produced at low cost. As a result of forming and measuring “H-L” recording films and “L-H” recording films by changing many manufacturing conditions, to increase the productivity of the recording film and make it easier to reduce the cost of the recording medium, the lower limit P of the reflectivity of an unrecorded part (“L” part) of the “L-H” recording film is set to 18%, its upper limit γ is set to 32%, the lower limit δ of the reflectivity of an unrecorded part (“H” part) of the “H-L” recording film is set to 40%, and its upper limit ε is set to 70% in this embodiment.
FIG. 13 shows the reflectivity ranges of a “H-L” recording film and a “L-H” recording film. When the reflectivity range at an unrecorded portion is determined as shown in FIG. 13, a signal appears in the same direction in emboss areas (including system lead-in SYLDI, etc.) and in recording mark areas (data lead-in/-out DTLDI, DTLDO and/or data area DTA) in the “L-H” recording film, with the groove level as a reference. Similarly, a signal appears in the opposite direction in emboss areas (including system lead-in SYLDI, etc.) and in recording mark areas (data lead-in/-out DTLDI, DTLDO and/or data area DTA) in the “H-L” recording film, with the groove level as a reference. Use of this phenomenon not only helps identify whether the recording film is a “L-H” recording film or a “H-L” recording film but also makes it easier to design a detecting circuit compatible with both of a “L-H” recording film and a “H-L” recording film.
The embodiment is characterized in that the same data frame is distributed over a plurality of small ECC blocks. Specifically, in the embodiment, two small ECC blocks constitute a large ECC block. The same data frame is distributed over the two small ECC blocks alternately. PI of a 10-byte size written in the middle is added to 172 bytes provided on its right side and PI of a 10-byte size written at the right end is added to 172 bytes provided on its left side and in the middle. That is, 172 bytes from the left end and PT of consecutive 10 bytes constitute a left small ECC block and 172 bytes in the middle and PI of 10 bytes at the right end constitute a right small ECC block.
According to this, the symbols in each frame are set. For example, “2-R” indicates which of data frame number and right and left small blocks it belongs to (e.g., it belongs to the right small ECC block in the second data frame). In addition, the data in the same physical sector is also distributed over the right and left small ECC blocks alternately in each physical sector finally configured. Here, the left-half column is included in the left small ECC block (the left small ECC block A shown in FIG. 14) and the right-half column is included in the right small ECC block (the right small ECC block B shown in FIG. 14).
The diagram (c) of FIG. 15 shows a data structure of recording management data RMD#1. In the diagram (c) of FIG. 15, the data structure of recording management data RMD#1 in the data lead-in area DTLDI is shown. Recording management data RMD#A, RMD#B recorded in the RMD duplication zone RDZ, (extended) recording management data RMD (the diagram (d) of FIG. 16) recorded in border-in area BRDI explained later, (extended) recording management data RMD recorded in the R zone, and/or RMD copy CRMD (the diagram (d) of FIG. 16) recorded in the border-out area BRDO may also have the same structure. As shown in the diagram (c) of FIG. 15, an item of recording management data RMD is configured to include a reserved area and “0” to “21” RMD fields. In the embodiment, one ECC block composed of 64 KB of user data contains 32 physical sectors. In one physical sector, 2 KB (to be exact, 2048 bytes) of user data are recorded. According to the user data size recorded in one physical sector, the individual RMD fields are divided in units of 2048 bytes and are assigned with relative physical sector numbers. RMD fields are recorded on a recordable information storage medium in the order of the relative physical sector numbers. The outline of data content recorded in each RMD field is as follows:
RMD field 0 . . . Information on the disc state and data area allocation (information on the location of various data in the data area);
RMD field 1 . . . Information on the test zone used and recommended recording waveforms;
RMD field 2 . . . Area available to the user;
RMD field 3 . . . Information on the starting position of the border area and the position of extended RMZ; and
RMD fields 4 to 21 . . . Information on the position of R zone.
When border closing is done, the unrecorded part of first and second R zones (open R zone) (the zones are called first, second, and third zones, starting from the inner periphery) is filled with “00h and border-out area is recorded outside the recorded data in the third zone (incomplete R zone). Border-in area is recorded outside the border-out area. In the border-in area, extended recording management zone EX.RMZ is recorded. As shown in FIG. 17, recording management data RMD can be updated 392 or more times (16384 times) using the extended recording management zone EX.RMZ in the border-in area. However, before extended recording management zone EX.RMZ in the border-in area is used, the border has to be closed, which takes time.
FIG. 18 is a flowchart for explaining the processing procedure immediately after an information storage medium is installed in an information reproducing apparatus or information recording and reproducing apparatus. When the disc is installed in or loaded into the apparatus, burst cutting area BCA is reproduced (ST22). This embodiment supports an HD DVD-R disc. It further supports both of the recording film polarities, “L-H” (Low to High) and “H-L” (High to Low). In ST24, the system lead-in area is reproduced. In ST26, RMD duplication RDZ is reproduced. In the case of a nonblank disc, recording management data RMD has been recorded in RMD duplication zone RDZ. According to the presence or absence of the recording of recording management data RMD, it is determined in ST28 whether the disc is a blank one. If the disc is a blank one (yes at ST28), the present process is ended. If the disc is not a blank disc (no at ST28), the latest recording management data RMD is searched for (ST30). Then, the number of the additionally recordable R zone now in use, the start physical segment number of the R zone, and the last recorded address LRA are found. Up to three additionally recordable R zones can be set. When a nonblank disc is discharged or unloaded, border closing or finalizing is done.
FIG. 19 is a flowchart for explaining a method of recording additional information onto a recordable information storage medium in the information recording and reproducing apparatus. When a host gives a record instruction (write (10)), it is determined in ST32 whether the remaining amount of recording management zone RMZ in which recording management data RMD is to be recorded is sufficient. If the remaining amount is not sufficient (no at ST32), the host is informed in ST34 that “the remaining amount of RMZ is small”. In this case, an extension of recording management zone RMZ is expected.
An information recording medium based on the above-mentioned format is prepared, and information recording of random data is performed. The result is that the jitter of L0 is 6.2% which is a very good performance. When the repetitive patterns of 7T marks and 7T space are recorded and reproduced, the waveform distortion is very low and the difference ([I11Lmax−I11Lmin]/I11Lmin) between the maximum and minimum values of I11L (which is the space level of a reproduction signal) is 3%. When the difference is equal to or less than 10%, the error rate (SbER) becomes not more than 1.0 e-04 as will be seen from FIG. 23, resulting in ensuring a sufficient practicability. Further, when the recording layer uses an organic dye material with which the physical deformation (change in the volume or change in the surface condition between the mark and its peripheral) at the recorded mark portion is equal to or less than 10%, as exemplified by FIG. 22, the error rate (SbER) becomes equal to or less than 1.0 e-04, thereby confirming the actual practicability.
FIG. 24 is an exemplary flowchart explaining a recording method using optical disc 100 according to one embodiment of the invention. (This disc uses an organic dye material for the recording layer by which no modification or no change will occur in recorded marks.) An optical pickup of a disc drive (not shown) generates or provides a modulated laser with a wavelength of, e.g., 405 nm. This laser is irradiated to the target recording layer (L0 or L1) of disc 100, so that object data (such as VOB of DVD or VOB/SOB of HD_DVD) is recorded thereon (ST100). When the recording is ended (yes at ST102), management information (such as VMG of DVD or HD_DVD) regarding the recorded object data is written in disc 100, to thereby complete one recording.
FIG. 26 is an exemplary view showing a physical sector layout of optical disc 100 shown in FIG. 1. As exemplified in FIG. 26, the information area provided throughout the dual layers includes seven areas: the System Lead-in area, Connection area, Data Lead-in area, Data area, Data Lead-out area, System Lead-out area, and Middle area. The Middle area on each layer allows the read-out beam to move from Layer 0 (L0) to Layer 1 (L1). Data area DA is intended for recording of the main data (such as management information VMG, object data VOB, etc. in the example of FIG. 1( e)). System Lead-in area SLA contains the Control data and Reference code. The Data Lead-out area allows for a continuous smooth read-out.
The initial zone contains embossed data segments. The main data of the data frame recorded as the data segment of the initial zone is set to “00h”. The buffer zone is formed of 1024 Physical sectors from 32 Data segments. The Main data of the Data frames eventually recorded as Data segments in this zone is set to “00h”. The Control data zone contains embossed Data segments. The Data segments contain embossed Control data. The Control data is comprised of 192 Data segments starting from PSN 123904 (01E400h).
BP149 and BP152 specify reflectance ratios of the data areas of Layer 0 and Layer 1. For example, 0000 1010b denotes 5%. An actual reflectance ratio can be specified by the following formula:
Actual reflectance ratio=value�(�).
1b (track on a land) Push-pull signal: 010 1000b denotes 0.40, for example.
An actual amplitude of a push-pull signal is specified by the following formula:
An actual amplitude of an on-track signal is specified by the following formula:
Incidentally, recording-related parameters for L0 as exemplified by FIG. 32 may be described at BP512 to BP543 of the physical format information. Information of the initial peak power and/or bias power, etc. for the L0 layer recording can be obtained from the description of FIG. 32. Further, recording-related parameters for L1 as exemplified by FIG. 33 may be described at BP544 to BP2047 of the physical format information. Information of the initial peak power and/or bias power, etc. for the L1 layer recording can be obtained from the description of FIG. 33.
(5) At least a part of the organic dye material to be used for the recording layer may include an azo metal complex (cf. FIGS. 2 to 4) comprising copper (Cu) or cobalt (Co) as its center metal.
(7) Assume that the recording laser wavelength is represented by λ, the numerical aperture of an objective lens for condensing the laser to the recording layer is represented by NA, the length of recorded patterns of marks and space is larger than 1.2*λ/NA, the maximum value of the reproduction signal level from the space is denoted by I11Lmax, and the minimum value thereof is denoted by I11Lmin. Under this assumption, the difference ([I11Lmax−I11Lmin]/I11Lmin) between the maximum and minimum values of the reproduction signal level from the space may be configured to be equal to or less than 10% (cf. FIG. 23).
(9) In the recording method, when a wavelength of the laser for recording is represented by λ, a numerical aperture of an objective lens for condensing the laser to the recording layer is represented by NA, and a length of recorded patterns of the marks and the space is larger than 1.2*λ/NA, a difference ([I11Lmax−I11Lmin]/I11Lmin) between maximum and minimum values of a reproduction signal level from the space may be configured to be equal to or less than 10%.
While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. For instance, the invention can be reduced to practice not only in a single/dual-layer disc, but in a future available optical disc with three or more recording layers,
Furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modification as would fall within the scope and spirit of the inventions.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5075147Mar 23, 1990Dec 24, 1991Fuji Photo Film Co., Ltd.Method for optically recording information and information recorded mediumUS5441848Apr 12, 1994Aug 15, 1995Tdk CorporationOptical recording/reproducing methodUS5958650 *Dec 19, 1997Sep 28, 1999Ciba Specialty Chemicals CorporationComplex polymethine dyes and their useUS6236635 *Sep 8, 1998May 22, 2001Hitachi, Ltd.Information recording method and apparatus with suppressed mark edge jittersUS6387467Oct 23, 2000May 14, 2002Ritek CorporationOptical recording medium structure and method of manufactureUS20020075793 *Sep 12, 2001Jun 20, 2002Tdk CorporationOptical recording mediumUS20030142606 *Dec 27, 2002Jul 31, 2003Kabushiki Kaisha ToshibaInformation recording apparatus and methodUS20030227846 *May 22, 2003Dec 11, 2003Samsung Electronics Co., Ltd.Recording medium for storing write protection information, and recording method and write protection method thereofUS20040114488 *Oct 29, 2003Jun 17, 2004Yasuo SawadaInformation recording apparatus and information recording methodUS20040125739 *Dec 16, 2003Jul 1, 2004Fuji Photo Film Co., Ltd.Optical information recording method and optical information recording mediumUS20040190431 *Jan 6, 2004Sep 30, 2004Samsung Electronics Co., Ltd.Optical recording medium, method and apparatus for recording data thereonUS20050058047 *Aug 17, 2004Mar 17, 2005Shinji FujitaOptical disk recording method, optical disk device and optical diskUS20050063266Aug 16, 2004Mar 24, 2005Kim Jin YongRecording medium, method of configuring control information thereof, recording and reproducing method using the same, and apparatus thereofUS20050063274Sep 16, 2004Mar 24, 2005Hitachi Maxell, Ltd.Information recording method and information recording mediumUS20050100704Dec 20, 2004May 12, 2005Tdk CorporationOptical recording mediumUS20050169140 *Jan 27, 2005Aug 4, 2005Sharp Kabushiki KaishaOptical recording condition setting method, optical recording/reproducing device, control program, and recording mediumUS20050237891 *Jul 1, 2005Oct 27, 2005Hidehiko KandoInformation recording method, information recording medium, and information recording apparatusUS20050243699 *Jul 7, 2005Nov 3, 2005Yoshihiro NodaOptical recording medium and recording/reading method thereforUS20050254403 *Oct 6, 2003Nov 17, 2005Hiromichi IshibashiOptical disc driveUS20060013111Nov 19, 2003Jan 19, 2006Tdk CorporationMethod for recording data onto optical recording medium, data recording device, and optical recording mediumUS20060046012Apr 13, 2005Mar 2, 2006Tdk CorporationCoating liquid, optical recording medium and method for producing the sameUS20060077831 *Oct 5, 2005Apr 13, 2006Samsung Electronics Co., Ltd.Optical disk recording device and method for recording data at high record-speed on low record speed optical diskUS20060120241 *Dec 6, 2005Jun 8, 2006Teruyasu WatabeMethod and apparatus for recording informationUS20060140096 *Dec 28, 2005Jun 29, 2006Victor Company Of Japan, Ltd.Optical recording method, optical recording apparatus and optical storage mediumUS20060215512May 22, 2006Sep 28, 2006Kim Jin YRecording medium, method of configuring control information thereof, recording and reproducing method using the same, and apparatus thereofUS20070165506 *Jan 6, 2005Jul 19, 2007Matsushita Electric Industrial Co., Ltd.Method and device for optical recording onto optical disc mediumCN1691164AApr 21, 2005Nov 2, 2005Tdk株式会社Coating liquid, optical recording media and method for producing sameEP1056078A1May 26, 2000Nov 29, 2000Fuji Photo Film Co., Ltd.Process for preparation of optical information recording disc, optical information recording disc and dye solutionEP1349159A1Mar 25, 2003Oct 1, 2003TDK CorporationOptical recording mediumEP1569208A1Nov 19, 2003Aug 31, 2005TDK CorporationMethod for recording data onto optical recording medium, data recording device, and optical recording mediumEP1587093A2Apr 4, 2005Oct 19, 2005Hayashibara Biochemical Laboratories, Inc.Dyes for optical recording mediumEP1864286A1Jan 30, 2006Dec 12, 2007Kabushiki Kaisha ToshibaInformation storage medium, reproducing method, and recording methodJP2000067463A Title not availableJP2000298874A Title not availableJP2002208227A Title not availableJP2003077127A Title not availableJP2003187443A Title not availableJP2004185796A Title not availableJP2004206849A Title not availableJP2005092942A Title not availableJP2005293773A Title not availableJP2005297406A Title not availableJPH09282660A Title not availableJPH09315002A Title not availableJPH10340489A Title not availableJPH11238310A Title not availableTW200603142A Title not availableWO2005017879A2Aug 13, 2004Feb 24, 2005Jin Yong KimRecording medium, method of configuring control information thereof, recording and reproducing method using the same, and apparatus thereofWO2006080572A1Jan 30, 2006Aug 3, 2006Toshiba KkInformation storage medium, reproducing method, and recording method* Cited by examinerNon-Patent CitationsReference1Anonymous: "Standard ECMA-364, Data interchange on 120 mm and 80 mm Optical Disk using +R DL Format-Capacity: 8,55 and 2,66 Gbytes per Side (Recording speed 2,4x)", ECMA International, 1st Edition, XP 2639565, Jun. 2005, 158 pages.2Anonymous: "White Paper Blu-ray Disc Format 1.B Physical Format Specifications for BD-R", XP-002324152, Aug. 1, 2004, pp. 1-33.3Anonymous: "Standard ECMA-364, Data interchange on 120 mm and 80 mm Optical Disk using +R DL Format—Capacity: 8,55 and 2,66 Gbytes per Side (Recording speed 2,4x)", ECMA International, 1st Edition, XP 2639565, Jun. 2005, 158 pages.4Extended European Search Report issued Jun. 16, 2011, in European Patent Application No. 11162905.1.5Extended European Search Report issued Jun. 30, 2011, in Patent Application No. 11162907.7.6Extended European Search Report issued Jun. 9, 2011, in European Patent Application No. 11162904.4.7Japanese Office Action issued May 24, 2011, in Patent Application No. 2010-113583 (with English-language translation).8Office Action issued Jan. 11, 2011, in Japanese Patent Application No. 2006-151584 with English translation.9Office Action issued Jan. 21, 2011, in European Patent Application No. 07109208.4-1232/1863026.10Office Action issued Oct. 21, 2010, in Taiwan Patent Application No. 096,119,181 (with English-language Translation).Classifications U.S. Classification369/59.11International ClassificationG11B7/0045Cooperative ClassificationG11B2007/0006, G11B7/00456, G11B7/2495, G11B7/249, G11B7/2467, G11B7/246European ClassificationG11B7/246, G11B7/249, G11B7/2495, G11B7/2467Legal EventsDateCodeEventDescriptionJul 12, 2007ASAssignmentOwner name: KABUSHIKI KAISHA TOSHIBA, JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:UMEZAWA, KAZUYO;MORITA, SEIJI;TAKAZAWA, KOJI;AND OTHERS;REEL/FRAME:019551/0091;SIGNING DATES FROM 20070531 TO 20070601Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:UMEZAWA, KAZUYO;MORITA, SEIJI;TAKAZAWA, KOJI;AND OTHERS;SIGNING DATES FROM 20070531 TO 20070601;REEL/FRAME:019551/0091Owner name: KABUSHIKI KAISHA TOSHIBA, JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:UMEZAWA, KAZUYO;MORITA, SEIJI;TAKAZAWA, KOJI;AND OTHERS;SIGNING DATES FROM 20070531 TO 20070601;REEL/FRAME:019551/0091RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services