JP3850741B2 - Optical recording method - Google Patents

Description

【００６３】
【化２】

【００６４】
【化３】

【００６５】
上記で得た光記録体に対して、発振波長660nm、ビーム径0.9μmの半導体レーザ光を用い、トラッキングしながらEFM信号を図９に示したマルチパルス記録条件（Ｖｘ、Ｖｘ／Ｖｒ、｛Ｔtop−[０．１３×（Ｖｘ／Ｖｒ）]Ｔ｝、Ｔmp、Ｔlpの各値、及び図８に示すような先頭加熱パルスのパルス幅の補正の有無、図８に示すような先頭加熱パルスのパルス幅の補正の有無、マルチパルス記録光のパルス数が（ｎ−１）、（ｎ−２）のいずれであるかという条件）と記録線速にてボトム・ジッタ（Bottom Jitter）が極小となるような記録パワーで記録し、その個所を再生してジッタ値を求めて評価した。
その評価結果から、実施例１〜７では比較例１〜４に比較してボトム・ジッタが良好であり、本実施形態の上記効果が充分に示された。
【００６６】
また、本発明の実施例８〜１１では、上記で得た光記録媒体に対して、発振波長660nm、ビーム径0.9μmの半導体レーザ光を用い、トラッキングしながらEFM信号を図１０に示すマルチパルス記録条件（Ｖｘ、Ｖｘ／Ｖｒ、｛Ｔtop−[０．１３×（Ｖｘ／Ｖｒ）]Ｔ｝、Ｔmp、Ｔlpの各値、図８に示すような先頭加熱パルスのパルス幅の補正の有無、マルチパルス記録光のパルス数が（ｎ−１）、（ｎ−２）のいずれであるかという条件）と記録線速度にてボトム・ジッタが極小となるような記録パワーで記録し、その個所を再生してジッタ値を求めた。図５及び図６はその結果を示し、図５はＴmpとボトム・ジッタとの関係、Ｔlpとボトム・ジッタとの関係を示す。
【００６７】
実施例８〜１１では、図５及び図６から明らかなように
１．０Ｔ≦Ｔtop−[０．１３×（Ｖｘ／Ｖｒ）]Ｔ≦１．６Ｔ
０．５５Ｔ≦Ｔmp≦０．７５Ｔ
０．５５Ｔ≦Ｔlp≦０．７５Ｔ
を満たす範囲でエラーを引き起こさないような１０％以下の低ジッタが得られることが明らかである。また、その効果はマルチパルス記録光のパルス数をマークデータ長ｎに対して（ｎ−２）として光記録媒体の記録層に記録マークを形成する場合に、より効果的である。
【００６８】
【発明の効果】
以上のように本発明によれば、有機色素を主成分とする記録層を有する光記録媒体の各記録線速度での良好な記録波形を得ることができる。
また、本発明によれば、ランドプリピット方式同様のデータ書き足し部における未記録領域を低減できる。
更に、本発明によれば、ランドプリピット方式に比較して、スタンパ作製時に於ける微細なカット幅制御やランドプリピット信号のデータ部への漏れ出しによるデータエラーを低減できる。
【図面の簡単な説明】
【図１】光記録媒体の構造を示す断面図である。
【図２】光記録媒体の他の構造を示す断面図である。
【図３】光記録媒体の別の構造を示す断面図である。
【図４】マルチパルス記録光の例を示す波形図である。
【図５】本発明の実施例８〜１１のＴmp、Ｔlpとボトム・ジッタとの関係を示す特性曲線図である。
【図６】同実施例８〜１１のＴtop−[０．１３×（Ｖｘ／Ｖｒ）]Ｔとボトム・ジッタとの関係を示す特性曲線図である。
【図７】本発明の実施形態で用いた光記録再生装置を示すブロック図である。
【図８】同実施形態の先頭加熱パルス幅の補正量を示す図である。
【図９】本発明の実施例１乃至実施例７及び比較例１乃至比較例４のマルチパルス記録条件及びジッタ値を示す図である。
【図１０】上記実施例８〜１１のマルチパルス記録条件及びジッタ値を示す図である。
【符号の説明】
１ 基板
２ 記録層
４ 保護層
６ 金属反射層
１１ 光記録媒体
１４ ピックアップ部
１５ 制御部[0001]
BACKGROUND OF THE INVENTION
  The present invention provides an optical recording that can record information by irradiating an optical recording medium with a light beam to cause optical changes such as transmittance and reflectance of the recording material to record information.About the methodTo do.
[0002]
[Prior art]
Optical recording media include CDs (Compact Discs) and DVDs (Digital Versatile Discs / Digital Video Discs). The optical recording media are optically irradiated with a light beam, such as the transmittance and reflectance of the recording material. Information is recorded by causing a change. Optical recording media that can be additionally recorded include DVD-R (DVD-Recrdable) and CD-R (CD-Recrdable). Pioneer R & D Vol.6 No.2 “Development of DVD-Recordable DVD-R Dye Disc Basic research on ISO / ODS '96: High Density of recording on Dye material Disc approach for 4.7 GB.
[0003]
An optical recording medium using a dye as a recording material and forming a recording mark on a recording layer with multi-pulse recording light is disclosed in JP-A-2000-030254, JP-A-2000-215508, JP-A-2001-076341, JP 2001-076343, JP 2001-110053, JP 2001-143263, JP 2001-155339, JP 2001-167436, JP 2001-167437, JP 2001. -176073, JP-A-2001-273636, JP-A-2001-273687, and JP-A-11-134703.
[0004]
Optical recording media using a polymethine dye as a recording material are disclosed in JP-A-10-83577, JP-A-10-119434, JP-A-10-149583, JP-A-10-188339, JP-A-10-278426. It is described in the gazette.
Optical recording media using a polymethine dye + light stabilizer as a recording material are disclosed in JP-A-10-109475, JP-A-10-109476, JP-A-10-134413, and JP-A-10-166739. Are listed.
[0005]
An optical recording medium using an azo metal chelate dye / metal reflective layer as a recording material is disclosed in Japanese Patent Publication No. 5-67438, Japanese Patent Application Laid-Open No. 7-161069, Japanese Patent Application Laid-Open No. 8-156408, and Japanese Patent Application Laid-Open No. 8-231866. JP-A-8-332772, JP-A-9-58123, JP-A-9-175031, JP-A-9-193545, JP-A-9-274732, JP-A-9-277703, Japanese Unexamined Patent Publication Nos. 10-6644, 10-6650, 10-6651, 10-36693, 10-44606, 10-58828, 10 JP-A-86519, JP-A-10-149484, JP-A-10-157293, JP-A-10-157300, JP-A-10-157301, JP-A-10-157302, JP-A-10-181199, JP-A-10-18201, JP-A-10-181203, JP-A-10-181206, JP-A-10 JP-A-188340, JP-A-10-188341, JP-A-10-188358, JP-A-10-208303, JP-A-10-214423, JP-A-10-228671, JP-A-10-36693. And JP-A-11-12483.
[0006]
Optical recording media using a tetraazaporphyrin (porphyrazine) dye / metal reflective layer as a recording material are described in JP-A-9-267562, JP-A-9-309268, and JP-A-10-856. Yes.
Other optical recording media using a dye / metal reflection layer as a recording material are disclosed in JP-A-10-86517, JP-A-10-93788, JP-A-10-226172, JP-A-10-244552, These are described in JP-A-10-287819, JP-A-10-297103, JP-A-10-309871, and JP-A-10-309872.
[0007]
An optical recording medium using a cyanine dye + azo metal chelate dye (salt-forming dye) / metal reflective layer as a recording material is disclosed in Japanese Patent Publication No. 7-51682, Japanese Patent Laid-Open No. 11-34499, WO 98/29257, JP-A-9-323478, JP-A-11-195242, JP-A-11-250505, JP-A-2000-168237, JP-A-2000-190642, JP-A-2000-190642, JP-A-2000. -198273.
[0008]
An optical recording medium using a formazan (metal chelate) dye + other dye as a recording material is disclosed in Japanese Patent No. 02791944, Japanese Patent Application Laid-Open No. 8-295079, Japanese Patent Application Laid-Open No. 9-095520, Japanese Patent Application Laid-Open No. 9-193546. JP-A-10-337958.
[0009]
Optical recording media using dipyrromethene (metal chelate) dye + other dye as recording materials are disclosed in JP-A-10-162430, JP-A-10-166732, JP-A-10-226172, JP-A-11-042858. Publication No. 11-042858, No. 11-092682, No. 11-165465, No. 11-208111, No. 11-227332, No. 11-227333 JP-A-11-255774 and JP-A-11-256057.
[0010]
[Problems to be solved by the invention]
Currently, DVD-R is being developed as a next-generation large-capacity optical disk. Elemental technologies for improving the recording capacity of DVD-R include the development of recording materials for minimizing recording pits, the adoption of image compression technology represented by MPEG2, and the development of technology for shortening the wavelength of semiconductor lasers for reading recorded pits. is required.
[0011]
Up until now, only 670 nm band AlGaInP laser diodes have been commercialized for bar code readers and measuring instruments as red wavelength semiconductor lasers. It is being used in the optical storage market. In the case of a DVD drive device, the light source is standardized at two wavelengths by a laser diode of 635 nm band and 650 nm band. On the other hand, a read-only DVD-ROM drive device is commercialized with a wavelength of ˜650 nm.
[0012]
In general, a dye-based write-once DVD in which pits (marks) are formed by a heat mode is different in that the pulse width and recording power of multi-pulse recording light by laser light emission at a specific recording linear velocity are optimized. At the recording linear velocity, the state of marks and spaces formed changes. That is, in the dye-based recordable DVD, the heat capacity is insufficient due to the leading heating pulse of the multi-pulse recording light necessary for the formation of the mark, or the average length of the mark varies depending on the heating temperature that reaches the optimum decomposition temperature. Jitter characteristics deteriorate due to variations, the duty ratio of the heating pulse of the optimal multi-pulse recording light being different, and a uniform mark width cannot be obtained, and the mark becomes thicker or thinner depending on the mark length. .
[0013]
Further, regarding the physical format of the DVD recording system, the DVD-R format is standardized by a format in which a part of a land portion called a land prepit is cut. If this land prepit method is used, if the land prepit is 0.16 (unit: μm) or less, prepit information such as a prepit address cannot be reproduced well, and the land prepit is 0.32 or more. This time, the land pre-pit signal itself behaves like a noise in the data area, and many data errors occur. Therefore, the land pre-pits must be controlled so that the cut width suitable for the recording material is finely adjusted by the stamper so that the land cut width is in the range of 0.16 to 0.32.
[0014]
  The present invention provides an optical recording capable of obtaining a good recording waveform at each recording linear velocity of an optical recording medium having a recording layer containing an organic dye as a main component.Proposed methodThe purpose is to provide.
  Further, the present invention provides an optical recording that can reduce an unrecorded area in a data added portion similar to the land pre-pit system.Proposed methodThe purpose is to provide.
[0015]
  Furthermore, the present invention provides optical recording that can reduce data errors due to fine land prepit cut width control and leakage of the land prepit signal to the data portion during stamper fabrication, compared to the land prepit method.Proposed methodThe purpose is to provide.
[0016]
[Means for Solving the Problems]
  In order to achieve the above object, the invention according to claim 1 is characterized in that the recording is performed by irradiating an optical recording medium having a recording layer mainly composed of an organic dye on a substrate having a guide groove with multipulse recording light. In an optical recording method for forming a recording mark on a layer, the optical recording medium comprises:The format has no land pre-pits, andThe substrate groove has a wobble having a frequency corresponding to a period of 4T to 96T, and a recording mark is formed in the recording layer with a multi-pulse recording light satisfying the following formula.
[0017]
  1.0T ≦ Ttop− [0.13 × (Vx / Vr)] T ≦ 1.6T
  0.55T ≦ Tmp ≦ 0.75T
  0.55T ≦ Tlp ≦ 0.75T
  Where Vx is the recording linear velocity, Vr is the standard reproduction speed of the optical recording medium, T is the recording clock period, Ttop is the leading pulse length of the multipulse recording light, and Tmp is the multipulse recording light per recording mark. When the number of pulses is 3 or more, the intermediate pulse length of the multi-pulse recording light and Tlp is the rear end pulse length of the multi-pulse recording light.
[0018]
  The invention according to claim 2 is the optical recording method according to claim 1,The optical recording medium has a ratio between the amplitude Wo of the wobble signal and the amplitude PP of the push-pull signal. ( W o / PP ) Is 0.1 ≦ W o /PP≦0.4It is characterized by that.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
  In an embodiment of the present invention, a recording mark is formed on the recording layer by irradiating a multi-pulse recording light to a dye-based optical recording medium in which a recording layer mainly composed of an organic dye is provided on a substrate having a guide groove. In the optical recording method toAs described belowRecording marks were formed on the recording layer with multi-pulse recording light satisfying the following formula.
[0027]
  1.0T ≦ Ttop− [0.13 × (Vx / Vr)] T ≦ 1.6T
  0.55T ≦ Tmp ≦ 0.75T
  0.55T ≦ Tlp ≦ 0.75T
  Where Vx is the recording linear velocity, Vr is the standard reproduction speed (3.5 m / s) of the optical recording medium, T is the recording clock period, and Ttop is the leading pulse length of the multipulse recording light (pulse width of the leading pulse). , Tmp is the intermediate pulse length of the multi-pulse recording light when the number of pulses of the multi-pulse recording light per recording mark is 3 or more (pulse width of the intermediate pulse between the first pulse and the rear end pulse), Tlp is the rear end pulse length (pulse width of the rear end pulse) of the multi-pulse recording light.
[0028]
The dye-based optical recording medium has a wobble having a frequency corresponding to a period of 4T to 96T, and the recording layer has a refractive index p of 1. as a recording layer with respect to light in the wavelength range of recording / reproducing wavelength ± 5 nm. An optical recording medium having an organic dye film in which 5 ≦ p ≦ 3.0 and the extinction coefficient k is 0.02 ≦ k ≦ 0.2 was obtained.
[0029]
As a result, in the present embodiment, as the dye-based optical recording medium, the unrecorded area at the beginning of the added data portion can be reduced, and a DVD write-once disc with a low error rate is obtained. That is, in the present embodiment, by selecting a parameter of a multi-pulse recording light waveform corresponding to each recording linear velocity, combining a high frequency wobble format and a dye-based recording layer, each recording linear velocity is obtained. Good recording waveform can be obtained, unrecorded area at the beginning of the added data part can be reduced as in the land pre-pit method, and compared with the land pre-pit method, fine cut width control and land at the time of stamper production A DVD write-once disc capable of reducing data errors due to leakage of the prepit signal to the data portion was obtained.
[0030]
In this embodiment, the number of pulses of multi-pulse recording light per recording mark formed on the recording layer of the optical recording medium is determined when the mark data length (mark length with respect to the recording clock period T) is n ( It is preferable to set the number of pulses to (n-1) or (n-2), more preferably to the number of (n-2) pulses. When the number of pulses of the multi-pulse recording light per recording mark is set to (n−2) pulses, the multi-pulse recording light has a minimum mark length of 3T as shown in FIG. When recording a mark having a mark length of only the leading heating pulse, only the leading heating pulse is recorded, and when recording a mark having a 6T mark length, the leading heating pulse, the trailing edge heating pulse, and the leading heating pulse and trailing edge heating pulse are present. It consists of two intermediate pulses. The multi-pulse recording light has (n−2) heating pulses including a leading heating pulse and a trailing heating pulse when recording marks having other mark lengths. The heating pulse is, for example, a pulse that is inverted between the recording power Pp and the bias power Pb, and the pulse width of the leading heating pulse is Ttop. The pulse width of the rear end heating pulse is Tlp, and the pulse width of the intermediate pulse is Tmp.
[0031]
Also, due to the influence of thermal interference, when the length of the space immediately before the mark formed on the recording layer is the shortest length, the length of the head heating pulse of the multi-pulse recording light for forming the mark is Set the head heating pulse of the multi-pulse recording light other than the multi-pulse recording light other than the multi-pulse recording light for forming the mark to be shorter than the pulse width of the head heating pulse of the multi-pulse recording light to form the shortest mark. By setting the pulse width longer than the leading heating pulse of the multi-pulse recording light for forming other marks other than the mark, recording with lower jitter can be realized.
[0032]
When the length of the space immediately before the mark formed on the recording layer is the shortest length, the pulse length of the head heating pulse of the multi-pulse recording light for forming the mark is set to the multi-pulse for forming the mark. The specific length that is shorter than the pulse width of the leading heating pulse of the multi-pulse recording light other than the recording light is particularly preferably set in the range of 0.02T to 0.10T, and is formed in the recording layer. When the length of the space immediately before the mark is the shortest length, when the length of the leading pulse of the multi-pulse recording light for forming the mark is substantially equal to the length of the leading heating pulse of the other multi-pulse recording light, Due to the thermal interference, the length of the space immediately before the recording mark is shortened, and the jitter is slightly deteriorated.
[0033]
Therefore, only when the length of the space immediately before the mark formed on the recording layer is the shortest length, the leading pulse of the multi-pulse recording light for forming the mark is pulsed from the leading heating pulse of the other multi-pulse recording light. Needless to say, shortening the width is effective, and it is effective to shorten the leading edge of the leading pulse when the leading pulse is shortened.
[0034]
Further, when the length of the space immediately before the mark formed on the recording layer is the shortest length, if the head pulse length of the multi-pulse recording light for forming the mark is shorter than 0.10 T, the mark itself is It becomes too short. The specific length for setting the head heating pulse of the multi-pulse recording light for forming the shortest mark longer than the head heating pulse of the multi-pulse recording light for forming the mark of other mark length is 0. A range of .05T to 0.25T is preferred. This increases the length of the first pulse of the multi-pulse recording light to form the shortest length mark in the above range because it becomes difficult to form the shortest length mark especially when the recording linear velocity increases. It is. Specifically, the correction amount of the pulse width (front edge) of the leading heating pulse of the multi-pulse recording light for forming the mark of each mark length is specifically the length of the space immediately before the mark to be formed, for example, FIG. Set as shown in.
[0035]
That is, when the length of the space immediately before the mark formed on the recording layer is the shortest length, the correction amount of the pulse width (front edge) of the leading heating pulse of the multi-pulse recording light for forming the mark is ± The correction amount of the pulse width (front edge) of the leading heating pulse of the multi-pulse recording light other than the multi-pulse recording light for forming the mark is set to -0.05T. Further, when the length of the space immediately before the mark formed on the recording layer is a length other than the shortest length, the pulse width (front edge) of the leading heating pulse of the multi-pulse recording light for forming the shortest mark is formed. ) Is set to + 0.05T, and the correction amount of the pulse width (front edge) of the leading heating pulse of the multi-pulse recording light for forming other marks other than the shortest mark is set to ± 0.00T. Set.
[0036]
In the present embodiment, for example, optical recording and reproduction as described above are performed by an optical recording / reproducing apparatus as shown in FIG. The optical recording medium 11 is set on a turntable 12, and the optical recording medium 11 rotates when the turntable 12 is driven to rotate by a motor 13. The pickup unit 14 emits the multi-pulse recording light having a wavelength of 600 to 720 nm with a semiconductor laser as a light source, and irradiates the recording layer of the optical recording medium 11 as a light spot through an optical system including an objective lens. As a result, a recording mark is formed on the recording layer to record information.
[0037]
The pickup unit 14 irradiates the recording layer of the optical recording medium 11 as a light spot with a light beam from the semiconductor laser via an optical system including an objective lens, and the reflected light (or transmitted light) is optical including the objective lens. Information is reproduced from the optical recording medium 11 by receiving light at the light receiving unit through the system and obtaining a reproduction signal. Further, the pickup unit 14 detects the light that does not trace the guide groove of the recording layer, out of the reflected light (or transmitted light) incident from the recording layer of the optical recording medium 11 via the optical system including the objective lens. A tracking error signal is detected by receiving a light from a detection light receiving element (for example, a two-divided light receiving element) and obtaining a difference between output signals of the light receiving element, and the tracking error signal is passed through a noise removing filter to be a push-pull signal. The objective lens is controlled by this push-pull signal to perform tracking control.
[0038]
The control unit 15 is a control means for controlling the entire optical recording / reproducing apparatus, and performs the setting and control as described above. The control unit 15 generates a modulation signal based on the EFM data as recording information and a recording clock, modulates the semiconductor laser of the pickup unit 14 with the modulation signal, and outputs the multipulse recording light from the semiconductor laser. Let it emit. Further, the control unit 15 obtains a wobble signal through a filter through the tracking error signal, controls the data writing position with a signal obtained by modulating the wobble signal, and performs synchronization in the wobble.
[0039]
Next, the configuration of the optical recording medium will be described. Items necessary for configuring the recording layer of the optical recording medium include optical characteristics. The conditions necessary for this optical characteristic are that the refractive index p of the recording layer single layer with respect to light in the wavelength range near the long wavelength near the recording / reproducing wavelength is 1.5 to 3.0 and the extinction coefficient k is 0. It is preferably in the range of 02 or more and 0.2 or less. When p is less than 1.5, it is difficult to obtain a sufficient optical change of the recording layer, which is not preferable because the recording modulation degree is low, and when p exceeds 3.0, Since the wavelength dependency becomes too high, an error occurs even in the recording / reproducing wavelength region, which is not preferable. Further, when k is less than 0.02, it is not preferable because the recording sensitivity is deteriorated. When k exceeds 0.2, it is difficult to obtain a reflectance of 50% or more in the recording layer. This is not preferable.
[0040]
Next, the characteristics of the wobble in which the guide groove of the optical recording medium is meandered in advance will be described. Here, T used to define the wobble frequency is recorded when the mark is recorded on the recording layer of the optical recording medium at the recording clock cycle. The pit length (unit: μm) is about 0.133 μm for DVD (4.7 GB), and about 38 nsec. In terms of time. Usually, a frequency band corresponding to 150T to 400T is used as the wobble frequency band. If the wobble frequency band is a frequency band corresponding to 150T to 400T, when adding data regardless of frequency modulation or phase modulation, the wobble frequency is too low, and the data between the previous data and the added data is too low. Is quite empty and is not suitable for high-density recording.
[0041]
On the other hand, in the DVD-R, a land pre-pit is conventionally provided, and a data writing position is controlled by the land pre-pit signal. However, in the land pre-pit system, if the land pre-pit amplitude is too small, the land pre-pit cannot be read satisfactorily. Conversely, if the land pre-pit amplitude is too large, the land pre-pit signal itself leaks to the write data. Therefore, the land pre-pit LPP is in a range of 0.16 ≦ LPP ≦ 0.32, preferably 0.18 ≦ LPP ≦ 0.26 (unit: μm). Therefore, the cut width of the land portion must be finely controlled when creating the stamper. Further, if the wobble is changed to a high-frequency wobble, no land pre-pit is required, and the wobble signal is modulated and synchronized, so that a situation in which data errors occur frequently as in the land pre-pit method does not occur.
[0042]
The wobble amplitude in the optical recording medium of the present embodiment is the ratio Wo / of the push-pull signal PP obtained by filtering the tracking error signal to the amplitude Wo of the wobble signal obtained by filtering the tracking error signal as described above. If PP = NW0 is set to a range of 0.1 ≦ NW0 ≦ 0.4, synchronization with the target wobble is possible, and a more preferable value of NW0 is within a range of 0.15 ≦ NW0 ≦ 0.30. Is the value of
[0043]
If the value of NW0 is 0.1 or less, the wobble signal has insufficient signal strength to synchronize with the wobble signal. If the value of NW0 exceeds 0.4, errors in the data portion increase. There is a tendency. However, the increase in wobble amplitude is less affected by the occurrence of data errors than data errors in optical recording media with large land prepits compared to the land prepit method. It is moderate.
[0044]
Furthermore, when creating a stamper, advanced cut width control technology is required to make the cut width of the land prepit LPP of the land prepit type LPP within the range of LPP = 0.16 to 0.32. In a high-frequency wobble system like the form, the objective is achieved only by managing the high-frequency generation source and the wobble swing amount (the circuit that controls the wobble swing amount can be created arbitrarily with good reproducibility). Therefore, the yield of the stamper and the yield of the optical recording medium can be greatly improved.
[0045]
As for the guide groove shape of the substrate having the above format of the optical recording medium, the recording layer is mainly formed by a solvent coating method using an organic dye. The thickness is 1000 to 2500 inches, and more preferably 1500 to 2000 inches. If the guide groove depth is 1000 mm or less, the push-pull signal cannot be sufficiently obtained and tracking control cannot be performed. If the guide groove depth is 2500 mm or more, the transferability is undesirably reduced when the substrate is formed. Further, when the dye-based recording layer is provided, the guide groove depth of the dye-based recording layer is 1200 ≦ d1 × when the wobble frequency is m (T) and the guide groove depth of the dye-based recording layer is d1. The range is m (T) ≦ 160000. If d1 × m (T) is less than 1200, a sufficient tracking error signal cannot be obtained, and sufficient tracking cannot be performed during recording and reproduction. When d1 × mm (T) exceeds 160000, it oscillates in the opposite direction and is also unfavorable for tracking. Further, as described above, there is a limit of the guide groove depth of the substrate from the transfer limit, and substantially exceeds 160000. It is not possible. The track pitch for securing a recording density of 4 GB to 5 GB is set to about 0.64 μm to 0.8 μm. Although the width of the guide groove varies depending on the recording material, almost all organic materials can be applied with a guide groove width of 0.18 to 0.40 μm.
[0046]
Next, specific examples of the dye material that can be used for the recording layer of the optical recording medium in the present embodiment are azo (metal chelate) dye, formazan (metal chelate) dye, dipyrromethene (metal chelate) dye, polymethine dye, and squarylium dye. Azaannulene dyes and the like are applicable, and specifically, metal chelate dyes, trimethine cyanine dyes, squarylium dyes, and tetraazaporphyrin dyes are particularly preferable.
[0047]
Regarding the thermal decomposition characteristics of the dyes listed above, the decomposition start temperature of the recording material is preferably 360 ° C. or less, and the decomposition start temperature of the recording material is particularly preferably 100 to 350 ° C. When the decomposition temperature of the recording material is 360 ° C. or higher, pit formation during recording is not performed well, and jitter characteristics are poor. If the decomposition temperature of the recording material is 100 ° C. or less, the storage stability of the optical recording medium is deteriorated.
[0048]
Next, the configuration of the optical recording medium in the present embodiment will be described.
The optical recording medium in the present embodiment has a structure as shown in FIG. 1, which is a normal write-once optical disk, that is, a structure in which a recording layer 2 is provided on a substrate 1 as shown in FIG. b) a structure in which an undercoat layer 3 and a recording layer 2 are provided in this order on a substrate 1, and an undercoat layer 3, a recording layer 2 and a protective layer 4 are provided on the substrate 1 as shown in FIG. As shown in FIG. 1D, an undercoat layer 3, a recording layer 2, and a protective layer 4 are provided in this order on the substrate 1, and a hard coat layer 5 is provided on the lower side of the substrate 1. Well, a so-called air sandwich in which two sheets as shown in FIG. 2 are bonded together, or a close bonding structure, that is, a recording layer 2, a metal reflective layer 6 and a protective layer on a substrate 1 as shown in FIG. A structure in which two layers 4 are laminated in order, on the substrate 1 as shown in FIG. A structure in which two layers each having an undercoat layer 3, a recording layer 2, a metal reflective layer 6 and a protective layer 4 are laminated together, as shown in FIG. 2C, the undercoat layer 3 and the recording layer on the substrate 1. 2, the metal reflective layer 6 and the protective layer 4 may be provided in this order, and a structure in which two hard coat layers 5 are provided below the substrate 1 may be laminated.
[0049]
Further, the optical recording medium in the present embodiment has the structure of the optical recording medium for CD-R as shown in FIG. 3, that is, the recording layer 2 and the metal reflective layer 6 on the substrate 1 as shown in FIG. And a structure in which the protective layer 4 is provided in order, as shown in FIG. 3B, a structure in which the recording layer 2, the metal reflective layer 6, the protective layer 4, the adhesive layer 8 and the protective substrate 7 are provided in order on the substrate 1. 3C, an undercoat layer 3, a recording layer 2, a metal reflective layer 6, a protective layer 4, an adhesive layer 8 and a protective substrate 7 are provided in this order on the substrate 1, and a hard coat layer is provided below the substrate 1. 5 may be provided.
[0050]
Next, necessary characteristics and examples of constituent materials of each layer of the optical recording medium in the present embodiment will be described.
As a configuration of the optical recording medium in the present embodiment, a basic structure is a structure in which a first substrate and a second substrate are bonded together with an adhesive via a recording layer. The recording layer may be a single organic dye layer or may be a laminate of an organic dye layer and a metal reflective layer in order to increase reflectivity. The recording layer and the substrate may be configured via an undercoat layer or a protective layer, or may be stacked to improve the function. The structure most commonly used is a structure in which a first substrate, an organic dye layer, a metal reflective layer, a protective layer, an adhesive layer, and a second substrate are sequentially provided.
[0051]
  The substrate of the optical recording medium must be transparent to the used light only when recording and reproduction is performed by irradiating light from the substrate side to the optical recording medium, and recording is performed by irradiating light from the recording layer side. The substrate does not have to be transparent when reproducing. As the substrate material of the optical recording medium, for example, polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide or other plastic, glass, ceramic, metal, or the like can be used. In addition, the guide groove for tracking and the guide on the surface of the substratePit etc.May be formed.
[0052]
The recording layer of the optical recording medium is to record some information by causing some optical change by irradiation of light, and it is necessary that the recording layer contains a dye. In forming the layer, the present embodiment uses a combination of two or more dyes. Furthermore, in the optical recording medium of the present embodiment, the dye may be mixed or laminated with other organic dyes, metals, and metal compounds for the purpose of improving optical characteristics, recording sensitivity, signal characteristics, and the like. Examples of the organic dyes include (poly) methine dyes, naphthalocyanine series, phthalocyanine series, squarylium series, croconium series, pyrylium series, naphthoquinone series, anthraquinone series (indanthrene series), xanthene series, triphenylmethane series, Examples include azulene-based, tetrahydrocholine-based, phenanthrene-based, and triphenothiazine-based dyes, and metal complex compounds.
[0053]
Examples of the above metals and metal compounds include In, Te, Bi, Se, Sb, Ge, Sn, Al, Be, TeO.₂, SnO, As, Cd, etc., which can be used in the form of dispersion mixing or lamination.
Furthermore, polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural polymers, silicones, liquid rubbers, or silane coupling agents may be dispersed and mixed in the above dyes. For the purpose of improvement, stabilizers (for example, transition metal complexes), dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers and the like can be used together.
[0054]
The recording layer can be formed by an ordinary method such as vapor deposition, sputtering, CVD or solvent coating. In the case of using the coating method, the above-described dye or the like can be dissolved in an organic solvent, and the coating can be performed by a conventional coating method such as spraying, roller coating, dipping, or spin coating. Examples of the organic solvent generally include alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, amides such as N, N-dimethylformamide and N, N-dimethylacetamide, dimethyl sulfoxide and the like Sulfoxides, ethers such as tetrahydrofuran, dioxane, diethyl ether and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethane, carbon tetrachloride and trichloroethane , Aromatics such as benzene, xylene, monochlorobenzene and dichlorobenzene, cellosolves such as methoxyethanol and ethoxyethanol, hexane and pen Down, cyclohexane, and hydrocarbons such as methylcyclohexane. The thickness of the recording layer is 100 to 10 μm, preferably 200 to 2000 μm.
[0055]
The undercoat layer of the optical recording medium is: (1) improved adhesion, (2) a barrier such as water or gas, (3) improved storage stability of the recording layer, (4) improved reflectivity, (5) It is used for the purpose of protecting the substrate from the solvent, and (6) formation of guide grooves, guide pits and preformats. For the purpose of (1), the undercoat layer is a polymer material such as ionomer resin, polyamide resin, vinyl resin, natural resin, natural polymer, silicone, liquid rubber, and various polymer compounds and silane cups. A ring agent or the like can be used, and for the purposes of (2) and (3), in addition to the above polymer materials, inorganic compounds such as SiO, MgF, SiO₂, TiO, ZnO, TiN, SiN and the like, and metal or semimetal such as Zn, Cu, Ni, Cr, Ge, Se, Au, Ag, Al, etc. can be used. For the purpose of (4), the undercoat layer can include metals such as Al, Au and Ag, and organic thin films having a metallic luster such as methine dyes and xanthene dyes. For the purposes (5) and (6), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the undercoat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.
[0056]
Examples of the metal reflective layer of the optical recording medium include metals and semimetals that are highly resistant to corrosion and are not easily corroded, and examples of materials include Au, Ag, Cr, Ni, Al, Fe, and Sn. However, Au, Ag, and Al are most preferable from the viewpoint of reflectivity and productivity, and these metals and metalloids may be used alone or as two kinds of alloys. Examples of the method for forming the metal reflective layer of the optical recording medium include vapor deposition and sputtering, and the thickness of the metal reflective layer of the optical recording medium is from 50 to 5000 mm, preferably from 100 to 3000 mm.
[0057]
The protective layer of the optical recording medium and the substrate hard coat layer (the hard coat layer) are: (1) protect the recording layer (reflection absorption layer) from scratches, dust, dirt, etc., (2) recording layer (reflection absorption) Layer) is used for the purpose of improving the storage stability and (3) improving the reflectance. The material for the undercoat layer can be used for the protective layer and the substrate-side hard coat layer for these purposes. In addition, the protective layer and the substrate surface hard coat layer are made of SiO, SiO₂Can also be used, such as polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, natural rubber, styrene butadiene resin, chloroprene rubber, wax, alkyd resin, Thermal softening and heat melting resins such as drying oil and rosin can also be used. The most preferable example of the above materials used for the protective layer and the substrate surface hard coat layer is an ultraviolet curable resin excellent in productivity. The film thickness of the protective layer or the substrate surface hard coat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm. In the optical recording medium of the present embodiment, the undercoat layer, the protective layer, and the substrate surface hard coat layer described above, as in the case of the recording layer, are a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, A surfactant, a plasticizer and the like can be contained.
[0058]
The protective substrate of the optical recording medium must be transparent to the light used when irradiating the optical recording medium from the protective substrate side, and transparency is not required when used as a simple protective plate. Absent. As the substrate material that can be used for the protective substrate in the optical recording medium, it is exactly the same as the material of the substrate, and plastics such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide, or Glass, ceramic, metal, or the like can be used.
[0059]
The adhesive and adhesive layer of the optical recording medium may be any material that can bond the two optical recording media, and in view of productivity, an ultraviolet curable adhesive or a hot melt adhesive is preferable.
[0060]
According to the present embodiment, by limiting the optimum multi-pulse recording light for each recording linear velocity, it becomes possible to perform recording with low jitter at any recording linear velocity. As described above, according to the present embodiment, the data portion can be efficiently written in a high-frequency wobble format that can be manufactured more easily than the land pre-pit format used in DVD-R, and is currently manufactured in large quantities. It is possible to provide an optical recording medium in almost the same format as the CD-R and DC-RW.
[0061]
Next, Examples 1 to 7 and Comparative Examples 1 to 4 of the present invention will be described. Examples 1 to 7 and Comparative Examples 1 to 4 have a guide groove depth of 1750 mm, a half width of 0.33 μm, a track pitch of 0.74 μm, a wobble frequency of 32T, a thickness of 0.6 mm, an outer diameter On a 120 mm injection-molded polycarbonate substrate, the following compounds of Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3 are weighed in a weight ratio of 60: 39: 1 and 2,2,3,3-tetrafluoro-1-propanol is used. After dissolution and spinner coating, an organic dye layer with a thickness of 1200 mm is formed, dried at 85 ° C. for 30 minutes, and then a reflective layer of 1000 mm silver is provided by sputtering, and further 5 μm thick with an acrylic photopolymer. Then, an injection-molded polycarbonate flat plate substrate having a thickness of 0.6 mm and an outer diameter of 120 mm was adhered with an acrylic photopolymer to obtain an optical recording medium.
[0062]
[Chemical 1]

[0063]
[Chemical 2]

[0064]
[Chemical Formula 3]

[0065]
A semiconductor laser beam having an oscillation wavelength of 660 nm and a beam diameter of 0.9 μm is used for the optical recording material obtained above, and the EFM signal is tracked while tracking the EFM signal shown in FIG. 9 (Vx, Vx / Vr, {Ttop -[0.13 × (Vx / Vr)] T}, Tmp, Tlp, and whether or not the pulse width of the leading heating pulse as shown in FIG. 8 is corrected, the leading heating pulse as shown in FIG. Whether or not the pulse width is corrected, the number of pulses of the multi-pulse recording light is (n-1) or (n-2)) and the recording linear velocity, the bottom jitter is minimal. Recording was performed with such a recording power, and the jitter value was obtained and evaluated by reproducing the portion.
From the evaluation results, in Examples 1 to 7, the bottom jitter was better than those in Comparative Examples 1 to 4, and the effects of the present embodiment were sufficiently shown.
[0066]
Further, in Examples 8 to 11 of the present invention, the EFM signal is shown in FIG. 10 while tracking a semiconductor laser beam having an oscillation wavelength of 660 nm and a beam diameter of 0.9 μm with respect to the optical recording medium obtained above. Recording conditions (Vx, Vx / Vr, {Ttop− [0.13 × (Vx / Vr)] T}, Tmp, Tlp values, presence / absence of correction of the pulse width of the leading heating pulse as shown in FIG. Recording is performed with a recording power that minimizes bottom jitter at the recording linear velocity (the condition that the number of pulses of the multi-pulse recording light is (n-1) or (n-2)). And the jitter value was obtained. 5 and 6 show the results, and FIG. 5 shows the relationship between Tmp and bottom jitter and the relationship between Tlp and bottom jitter.
[0067]
  In Examples 8-11, FIG.5 and FIG.6.Obvious fromlike
  1.0T ≦ Ttop− [0.13 × (Vx / Vr)] T ≦ 1.6T
  0.55T ≦ Tmp ≦ 0.75T
  0.55T ≦ Tlp ≦ 0.75T
It is clear that a low jitter of 10% or less that does not cause an error within the range satisfying the above can be obtained. The effect is more effective when the recording mark is formed on the recording layer of the optical recording medium with the number of pulses of the multi-pulse recording light being (n-2) with respect to the mark data length n.
[0068]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain a good recording waveform at each recording linear velocity of an optical recording medium having a recording layer containing an organic dye as a main component.
Further, according to the present invention, it is possible to reduce the unrecorded area in the data write-in portion similar to the land pre-pit system.
Furthermore, according to the present invention, compared to the land pre-pit system, it is possible to reduce data errors due to fine cut width control and leakage of the land pre-pit signal to the data part during stamper fabrication.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the structure of an optical recording medium.
FIG. 2 is a cross-sectional view showing another structure of the optical recording medium.
FIG. 3 is a cross-sectional view showing another structure of the optical recording medium.
FIG. 4 is a waveform diagram showing an example of multi-pulse recording light.
FIG. 5 is a characteristic curve diagram showing the relationship between Tmp, Tlp and bottom jitter in Examples 8 to 11 of the present invention.
6 is a characteristic curve diagram showing the relationship between Ttop- [0.13 × (Vx / Vr)] T and bottom jitter in Examples 8 to 11. FIG.
FIG. 7 is a block diagram showing an optical recording / reproducing apparatus used in an embodiment of the present invention.
FIG. 8 is a diagram showing a correction amount of a leading heating pulse width according to the embodiment.
FIG. 9 is a diagram showing multipulse recording conditions and jitter values of Examples 1 to 7 and Comparative Examples 1 to 4 of the present invention.
FIG. 10 is a diagram showing multipulse recording conditions and jitter values of Examples 8 to 11 described above.
[Explanation of symbols]
1 Substrate
2 Recording layer
4 Protective layer
6 Metal reflective layer
11 Optical recording media
14 Pick-up part
15 Control unit

Claims (2)

In the optical recording method in which a recording mark is formed on the recording layer by irradiating an optical recording medium having a recording layer mainly composed of an organic dye on a substrate having guide grooves with multi-pulse recording light. The medium has a format in which no land pre-pits exist, and has a wobble having a frequency corresponding to a period of 4T to 96T in the groove of the substrate. An optical recording method comprising forming a recording mark.
1.0T ≦ Ttop− [0.13 × (Vx / Vr)] T ≦ 1.6T
0.55T ≦ Tmp ≦ 0.75T
0.55T ≦ Tlp ≦ 0.75T
Where Vx is the recording linear velocity, Vr is the standard reproduction speed of the optical recording medium, T is the recording clock period, Ttop is the leading pulse length of the multipulse recording light, and Tmp is the multipulse recording light per recording mark. When the number of pulses is 3 or more, the intermediate pulse length of the multi-pulse recording light and Tlp is the rear end pulse length of the multi-pulse recording light.   2. The optical recording method according to claim 1, wherein the ratio (Wo / PP) between the amplitude Wo of the wobble signal and the amplitude PP of the push-pull signal is 0.1 ≦ Wo / PP ≦ 0.4. An optical recording method characterized by:

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