JPH08180414A - Optical information recording method - Google Patents
Optical information recording methodInfo
- Publication number
- JPH08180414A JPH08180414A JP6318571A JP31857194A JPH08180414A JP H08180414 A JPH08180414 A JP H08180414A JP 6318571 A JP6318571 A JP 6318571A JP 31857194 A JP31857194 A JP 31857194A JP H08180414 A JPH08180414 A JP H08180414A
- Authority
- JP
- Japan
- Prior art keywords
- recording
- laser power
- layer
- protective layer
- bit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 44
- 230000003287 optical effect Effects 0.000 title claims abstract description 24
- 239000010410 layer Substances 0.000 claims abstract description 59
- 239000011241 protective layer Substances 0.000 claims abstract description 21
- 239000000758 substrate Substances 0.000 claims abstract description 17
- 230000007704 transition Effects 0.000 claims abstract description 7
- 229910052787 antimony Inorganic materials 0.000 claims description 3
- 229910052732 germanium Inorganic materials 0.000 claims description 3
- 229910052714 tellurium Inorganic materials 0.000 claims description 2
- 230000006866 deterioration Effects 0.000 abstract description 5
- 230000000694 effects Effects 0.000 description 10
- 229910004298 SiO 2 Inorganic materials 0.000 description 8
- 239000010408 film Substances 0.000 description 7
- 238000001816 cooling Methods 0.000 description 6
- 238000002425 crystallisation Methods 0.000 description 5
- 230000008025 crystallization Effects 0.000 description 5
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 230000003252 repetitive effect Effects 0.000 description 3
- 229910001020 Au alloy Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000005280 amorphization Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 239000004417 polycarbonate Substances 0.000 description 2
- 229920000515 polycarbonate Polymers 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 230000003685 thermal hair damage Effects 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 229910005872 GeSb Inorganic materials 0.000 description 1
- 229910000618 GeSbTe Inorganic materials 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 229910052798 chalcogen Inorganic materials 0.000 description 1
- 150000001787 chalcogens Chemical class 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000003708 edge detection Methods 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920005668 polycarbonate resin Polymers 0.000 description 1
- 239000004431 polycarbonate resin Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000004781 supercooling Methods 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
- G11B7/006—Overwriting
- G11B7/0062—Overwriting strategies, e.g. recording pulse sequences with erasing level used for phase-change media
Landscapes
- Thermal Transfer Or Thermal Recording In General (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
- Optical Recording Or Reproduction (AREA)
- Optical Head (AREA)
Abstract
(57)【要約】
【目的】 本発明は信号振幅が大きく、かつ記録、消去
の繰り返しによる特性の劣化の小さい相転移型光記録媒
体を提供することを目的とする。
【構成】 基板上に少なくとも誘電体保護層、相転移型
光記録層、誘電体保護層、反射層を順に積層してなる光
学的情報記録用媒体に、少なくとも記録レーザーパワー
Ｐ1とＰ1より小さい消去レーザーパワーＰ2を用いて１
ビームオーバーライト記録する方法であって、ビットを
形成する記録パルスを該ビット長よりも短い複数のパル
スに分割し、分割した各パルスのレーザーパワーは記録
レーザーパワーＰ1とし、分割したパルスの間のレーザ
ーパワーを消去レーザーパワーＰ2の１／２より小さく
ゼロでないレーザーパワーＰ3としたことを特徴とする
記録方法。
(57) [Summary] [Object] It is an object of the present invention to provide a phase transition type optical recording medium having a large signal amplitude and having little deterioration in characteristics due to repeated recording and erasing. [Structure] An optical information recording medium having at least a dielectric protective layer, a phase transition type optical recording layer, a dielectric protective layer, and a reflective layer sequentially laminated on a substrate, and at least recording laser powers P 1 and P 1 1 with small erase laser power P 2
A method of beam overwrite recording, in which a recording pulse forming a bit is divided into a plurality of pulses shorter than the bit length, and the laser power of each divided pulse is a recording laser power P 1 The recording method is characterized in that the laser power of 3 is less than 1/2 of the erasing laser power P 2 and is not zero laser power P 3 .
Description
【０００１】[0001]
【産業上の利用分野】本発明は、光学的情報記録方法に
関し、レーザー光などの照射により、情報を記録、消
去、再生可能な光学的情報記録用媒体を用いて記録再生
する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording method, and more particularly to a method for recording / reproducing information by using an optical information recording medium capable of recording, erasing and reproducing information by irradiation of laser light or the like.
【０００２】[0002]
【従来の技術】近年、情報量の増大、記録再生の高密度
化、高速化の要求に応える記録媒体として、レーザー光
線を利用した光ディスクが開発されている。光ディスク
には、一度だけ記録が可能な追記型と、記録・消去が何
度でも可能な書換え型がある。2. Description of the Related Art In recent years, an optical disk using a laser beam has been developed as a recording medium that meets the demands for increasing the amount of information, increasing the recording and reproducing density, and increasing the speed. There are two types of optical disks: a write-once type that allows recording only once and a rewritable type that allows recording / erasing as many times as desired.
【０００３】書換え型光ディスクとしては、光磁気効果
を利用した光磁気記録媒体や、可逆的な結晶状態の変化
を利用した相変化媒体が挙げられる。相変化媒体は、外
部磁界を必要とせず、レーザー光のパワーを変調するだ
けで、記録・消去が可能であり、さらに、消去と再記録
を単一ビームで同時に行う１ビームオーバーライトが可
能であるという利点を有する。Examples of the rewritable optical disk include a magneto-optical recording medium utilizing a magneto-optical effect and a phase change medium utilizing a reversible change in crystal state. The phase change medium does not require an external magnetic field and can be recorded / erased only by modulating the power of the laser light, and further, 1-beam overwriting that simultaneously erases and re-records with a single beam is possible. It has the advantage of being.
【０００４】１ビームオーバーライト可能な相変化記録
方式では、記録膜を非晶質化させることによって記録ビ
ットを形成し、結晶化させることによって消去を行う場
合が一般的である。このような、相変化記録方式に用い
られる記録層材料としては、カルコゲン系合金薄膜を用
いることが多い。In the one-beam overwritable phase change recording method, it is general that the recording film is made amorphous to form a recording bit and is crystallized to erase. As a recording layer material used in such a phase change recording method, a chalcogen-based alloy thin film is often used.
【０００５】例えば、Ｇｅ−Ｔｅ系、Ｇｅ−Ｔｅ−Ｓｂ
系、Ｉｎ−Ｓｂ−Ｔｅ系、Ｇｅ−Ｓｎ−Ｔｅ系合金薄膜
等が挙げられる。記録膜は適度に結晶化、非晶質化しや
すいこと、結晶状態と非晶質状態の反射率差が大きいこ
と、熱による体積変化が小さいこと等の観点から選定さ
れる。For example, Ge-Te system, Ge-Te-Sb
System, In-Sb-Te system, Ge-Sn-Te system alloy thin film, and the like. The recording film is appropriately selected from the viewpoints of being easily crystallized and amorphized easily, having a large reflectance difference between a crystalline state and an amorphous state, and having a small volume change due to heat.
【０００６】一般に、書換え型の相変化記録媒体では、
相異なる構造を実現するために、２つの異なるレーザー
光パワーを用いる。この方式を、非晶質ビットと結晶化
された消去・初期状態で記録・消去を行う場合を例にと
って説明する。Generally, in a rewritable phase change recording medium,
Two different laser light powers are used to achieve different structures. This system will be described by taking as an example a case where recording / erasing is performed in an erased / initial state where an amorphous bit is crystallized.
【０００７】結晶化は、通常は記録層の結晶化温度より
十分高く、融点よりは低い温度まで記録層を加熱するこ
とによってなされる。この場合、冷却速度は結晶化が十
分なされる程度に遅くなるよう、記録層を誘電体層で挟
んだり、ビームの移動方向に長い楕円形ビームを用いた
りする。Crystallization is usually carried out by heating the recording layer to a temperature sufficiently higher than the crystallization temperature of the recording layer and lower than the melting point. In this case, the cooling layer is sandwiched between dielectric layers or an elliptical beam long in the beam moving direction is used so that the crystallization is slow enough to cause sufficient crystallization.
【０００８】一方、非晶質化は記録層を融点より高い温
度まで加熱し、急冷することによって行う。この場合、
上記誘電体層は十分な冷却速度（過冷却速度）を得るた
めの放熱層としての機能も有する。さらに、上述のよう
な、加熱・冷却過程における記録層の溶融・体積変化に
伴う変形や、プラスチック基板への熱的ダメージを防い
だり、湿気による記録層の劣化を防止する機能、レーザ
ー光の干渉を利用しコントラストを高める機能等が重要
である。On the other hand, the amorphization is performed by heating the recording layer to a temperature higher than the melting point and quenching it. in this case,
The dielectric layer also has a function as a heat dissipation layer for obtaining a sufficient cooling rate (supercooling rate). Furthermore, as described above, the function of preventing deformation due to melting and volume change of the recording layer during heating / cooling process, thermal damage to the plastic substrate, and preventing deterioration of the recording layer due to moisture, laser light interference It is important to use the function to increase the contrast.
【０００９】保護層材料の材質は、レーザー光に対して
光学的に透明で、適当な屈折率を有すること、融点・軟
化点・分解温度が高いこと、形成が容易であること、適
度な熱伝導性を有することなどの観点から選定される。
１ビームオーバーライトを行うには非晶質ビットを形成
する記録レーザーパワーと非晶質ビットを結晶化する消
去レーザーパワーを用いる。The material of the protective layer is optically transparent to laser light, has an appropriate refractive index, has a high melting point / softening point / decomposition temperature, is easy to form, and has a suitable heat resistance. It is selected from the viewpoint of having conductivity.
To perform 1-beam overwrite, a recording laser power for forming an amorphous bit and an erasing laser power for crystallizing the amorphous bit are used.
【００１０】非晶質ビットを形成する部分は記録レーザ
ーパワーを照射するが、特にディスクの回転速度が遅い
場合には、熱干渉の影響でビットの後端が前端と比較し
て幅が広くなる等の記録マーク歪が生じる。マーク歪は
特にマークエッジ検出方式で不都合を生じる。この歪を
改善するためビットを形成するための記録パルスを複数
のパルスに分割し、熱干渉の影響を小さくすることが提
案されている。The portion where the amorphous bit is formed is irradiated with the recording laser power. However, especially when the rotational speed of the disk is slow, the width of the rear end of the bit becomes wider than that of the front end due to the influence of thermal interference. The recording mark distortion such as the above occurs. Mark distortion causes inconvenience especially in the mark edge detection method. In order to improve this distortion, it has been proposed to divide the recording pulse for forming a bit into a plurality of pulses to reduce the influence of thermal interference.
【００１１】分割したパルス間のレーザーパワーを消去
パワーまで落とすことにより、特に低線速で熱干渉によ
る最高到達温度や冷却速度のビット前後での非対称が緩
和される。By reducing the laser power between the divided pulses to the erasing power, the maximum temperature reached and the asymmetry of the cooling rate before and after the bit due to thermal interference are alleviated especially at a low linear velocity.
【００１２】[0012]
【発明が解決しようとする課題】しかしながら、パルス
分割によりビット前後の対称性は改善されるものの、記
録信号強度が十分にとれない場合がある。これは一度溶
融した部分の冷却速度が遅いため再結晶化してしまい、
その結果ビットの幅が狭くなるためである。However, although the symmetry before and after the bit is improved by the pulse division, the recording signal strength may not be sufficiently obtained in some cases. This is recrystallized because the cooling rate of the once melted part is slow,
As a result, the width of the bit becomes narrow.
【００１３】このような場合、記録用レーザーパルスを
多少短くし、記録レーザーパワーを大きくすることによ
りビット長を変えずに幅を広げることができるが、繰り
返し記録による特性劣化が著しくなる。これは記録レー
ザーパワーを大きくすることにより到達温度が高くなっ
たり高温保持時間が長くなることにより、ディスクに与
える熱ダメージが大きくなるためである。In such a case, the width can be widened without changing the bit length by slightly shortening the recording laser pulse and increasing the recording laser power, but the characteristic deterioration due to repeated recording becomes remarkable. This is because when the recording laser power is increased, the reached temperature becomes higher and the high temperature holding time becomes longer, so that the heat damage given to the disk increases.
【００１４】本発明者らは記録パルス形状を検討するこ
とにより、信号振幅が大きく、かつ記録、消去の繰り返
しによる特性の劣化を小さくすることが可能であること
を見いだし本発明に到達した。The present inventors have found that by examining the recording pulse shape, it is possible to increase the signal amplitude and reduce the deterioration of characteristics due to repeated recording and erasing, and arrived at the present invention.
【００１５】[0015]
【課題を解決するための手段】本発明の要旨は、基板上
に少なくとも誘電体保護層、相転移型光記録層、誘電体
保護層、反射層を順に積層してなる光学的情報記録用媒
体に、少なくとも記録レーザーパワーＰ1とＰ1より小さ
い消去レーザーパワーＰ2を用いて１ビームオーバーラ
イト記録する方法であって、ビットを形成する記録パル
スを該ビット長よりも短い複数のパルスに分割し、分割
した各パルスのレーザーパワーは記録レーザーパワーＰ
1とし、分割したパルスの間のレーザーパワーを消去レ
ーザーパワーＰ2の１／２より小さくゼロでないレーザ
ーパワーＰ3としたことを特徴とする記録方法に関す
る。The gist of the present invention is to provide an optical information recording medium in which at least a dielectric protective layer, a phase transition type optical recording layer, a dielectric protective layer, and a reflective layer are sequentially laminated on a substrate. A method of performing one-beam overwrite recording using at least the recording laser power P 1 and an erasing laser power P 2 smaller than P 1 , wherein a recording pulse forming a bit is divided into a plurality of pulses shorter than the bit length. The laser power of each divided pulse is the recording laser power P.
The recording method is characterized in that the laser power between the divided pulses is 1 and the laser power P 3 is less than 1/2 of the erasing laser power P 2 and is not zero.
【００１６】分割したパルス間のレーザーパワーＰ3を
消去レーザーパワーＰ2の１／２より小さくすることに
より溶解した部分の冷却速度が大きくなりビット部が大
きくなる。その結果信号振幅が大きくなる。またビット
を大きくするために記録レーザーパワーＰ1を上げる必
要がないので、繰り返し記録特性も優れたディスクを得
ることができる。By making the laser power P 3 between the divided pulses smaller than 1/2 of the erasing laser power P 2 , the cooling rate of the melted portion is increased and the bit portion is increased. As a result, the signal amplitude increases. Further, since it is not necessary to increase the recording laser power P 1 in order to increase the bit size, it is possible to obtain a disc having excellent repetitive recording characteristics.
【００１７】ビットの大きさが本発明による記録方法と
従来のパルス分割法で大きく違わない場合であっても、
本発明の記録方法の方が熱ダメージが小さく、繰り返し
記録特性が優れる場合もある。これは、従来の記録法は
分割パルス間の消去レーザーパワーＰ2による熱干渉に
よって本発明の記録法より最高到達温度が高くなったり
高温での保持時間が長くなったりしているためであると
考えられる。Even if the bit size is not significantly different between the recording method according to the present invention and the conventional pulse division method,
In some cases, the recording method of the present invention causes less thermal damage and is superior in repetitive recording characteristics. This is because the conventional recording method has a higher maximum attainable temperature or a longer holding time at a high temperature than the recording method of the present invention due to thermal interference due to the erasing laser power P 2 between divided pulses. Conceivable.
【００１８】分割したパルス間のレーザーパワーＰ3が
消去レーザーパワーＰ2の１／２以上である場合にはこ
れらの効果は小さくなる。また、分割したパルス間のレ
ーザーパワーＰ3がゼロであるとトラッキングおよびフ
ォーカスをその間制御できなくなる。パルスの分割法は
媒体の層構成やディスク回転速度、Ｐ1、Ｐ2、Ｐ3等の
値によって適当なものが選ばれるが、ビット先端部は直
前のレーザーパワーが消去パワーＰ2であり通常温度が
上がりにくいため、先頭の分割パルスのパルス幅をビッ
ト中間部や後端部より長くすると良い場合がある。These effects become small when the laser power P 3 between the divided pulses is ½ or more of the erasing laser power P 2 . If the laser power P 3 between the divided pulses is zero, tracking and focus cannot be controlled during that time. The pulse division method is selected appropriately depending on the layer structure of the medium, the disk rotation speed, and the values of P 1 , P 2 , P 3, etc., but the laser power immediately before the bit tip is the erasing power P 2 Since it is difficult for the temperature to rise, it may be preferable to make the pulse width of the leading divided pulse longer than the bit middle portion or the trailing end portion.
【００１９】また、分割パルス間のレーザーパワーＰ3
を小さくすることに加えて、分割パルス群の直前または
直後に消去レーザーパワーＰ2の１／２よりも小さいパ
ワー部を設けた記録波形とすることにより再結晶化部を
小さくしてもよい。図１は記録パルス群の直後に消去レ
ーザーパワーＰ2の１／２よりも小さいパワー部Ｐ3を設
けた例である。Also, the laser power P 3 between the divided pulses is
In addition to making the recording pulse width smaller, the recrystallized portion may be made smaller by providing a recording waveform in which a power portion smaller than 1/2 of the erase laser power P 2 is provided immediately before or after the divided pulse group. FIG. 1 shows an example in which a power portion P 3 smaller than 1/2 of the erase laser power P 2 is provided immediately after the recording pulse group.
【００２０】また、従来記録法において分割パルス間の
消去パワー照射部の一部分のレーザーパワーを消去レー
ザーパワーの１／２より小さくすることによっても同様
の効果が得られる。すなわち図３−ａ、ｂ、ｃのような
記録パルスとしても良い。分割パルス間のレーザーパワ
ーＰ3を消去レーザーパワーとする従来のパルス分割記
録法では再結晶化する部分が大きくなりビットが小さく
なるが、この現象は記録層と反射層の間の誘電体保護層
が厚く、熱の逃げにくい層構成のとき顕著となる。Further, in the conventional recording method, the same effect can be obtained by making the laser power of a part of the erase power irradiation portion between divided pulses smaller than 1/2 of the erase laser power. That is, recording pulses as shown in FIGS. 3-a, b, and c may be used. In the conventional pulse division recording method in which the laser power P 3 between divided pulses is used as the erase laser power, the recrystallized portion becomes large and the bit becomes small. This phenomenon is caused by the dielectric protective layer between the recording layer and the reflection layer. Is remarkable when the layer structure is thick and the heat does not easily escape.
【００２１】したがって相変化光ディスクに望まれてい
る高記録感度化に関して重要な技術になると考えられ
る。また、記録層がＧｅ、Ｓｂ、Ｔｅからなる場合は特
にＧｅ含有量が２０％以上のとき顕著となり、３０％以
上のときはさらに顕著となる。Ｇｅ含有量が多いと信号
振幅は大きくすることができるため、信号振幅を大きく
する必要のあるＣＤ−ＲＯＭと互換性をもつ書換媒体の
開発に関しても重要な技術になると考えられる。Therefore, it is considered to be an important technique for increasing the recording sensitivity desired for the phase change optical disk. Further, when the recording layer is made of Ge, Sb, or Te, it becomes remarkable especially when the Ge content is 20% or more, and becomes more remarkable when the Ge content is 30% or more. Since the signal amplitude can be increased when the Ge content is large, it is considered to be an important technique for the development of a rewritable medium compatible with a CD-ROM that requires the signal amplitude to be increased.
【００２２】本発明における記録媒体の基板としては、
ガラス、プラスチック、ガラス上に光硬化性樹脂を設け
たもの等のいずれであってもよい。基板、記録層を保護
するため保護層を設ける必要があるが、保護層として耐
熱性に優れ、基板の熱的変形防止効果があり、基板との
密着性の強いものを用いれば、現在光ディスク用基板と
して一般的に使用されているポリカーボネート樹脂基板
を使用することが可能である。As the substrate of the recording medium in the present invention,
It may be any of glass, plastic, glass provided with a photocurable resin, and the like. It is necessary to provide a protective layer to protect the substrate and recording layer, but if a protective layer that has excellent heat resistance and the effect of preventing thermal deformation of the substrate and has strong adhesion to the substrate is used, it is currently used for optical discs. It is possible to use a polycarbonate resin substrate generally used as the substrate.
【００２３】保護層の厚みは、１０から５００ｎｍの範
囲であることが望ましい。一般に保護層の厚みが１０ｎ
ｍ未満であると、基板や記録膜の変形防止効果が不十分
である。一方、プラスチック基板を用いた場合、５００
ｎｍを越えると、保護層自体の内部応力や基板との弾性
特性の差が顕著になって、クラックが発生しやすくな
る。The thickness of the protective layer is preferably in the range of 10 to 500 nm. Generally, the thickness of the protective layer is 10n
When it is less than m, the effect of preventing the deformation of the substrate and the recording film is insufficient. On the other hand, when using a plastic substrate, 500
If the thickness exceeds nm, the internal stress of the protective layer itself and the difference in elastic properties from the substrate become remarkable, and cracks are likely to occur.
【００２４】記録感度を良くするためには記録層と反射
層の間の保護層膜厚は１００ｎｍ以上が好ましい。ま
た、このとき再結晶化しやすくなるため、本発明による
記録法の効果が大きくなる。相変化光記録層はＧｅＳｂ
Ｔｅ系、ＩｎＳｂＴｅ系等が用いられ、結晶化速度、非
晶質化のしやすさ、結晶粒径、保存安定性等の改善のた
めＳｎ、Ｉｎ、Ｇｅ、Ｐｂ、Ａｓ、Ｓｅ、Ｓｉ、Ｂｉ、
Ａｕ、Ｔｉ、Ｃｕ、Ａｇ、Ｐｔ、Ｐｄ、Ｃｏ、Ｎｉ等を
加えてもよい。In order to improve the recording sensitivity, the thickness of the protective layer between the recording layer and the reflective layer is preferably 100 nm or more. In addition, at this time, recrystallization easily occurs, so that the effect of the recording method according to the present invention becomes large. The phase change optical recording layer is GeSb
Te-based, InSbTe-based, etc. are used, and Sn, In, Ge, Pb, As, Se, Si, Bi are used for improving crystallization speed, easiness of amorphization, crystal grain size, storage stability and the like. ,
You may add Au, Ti, Cu, Ag, Pt, Pd, Co, Ni, etc.
【００２５】その厚みは一般的に１０ｎｍから１００ｎ
ｍの範囲に選ばれる。記録層の厚みが１０ｎｍより薄い
と十分なコントラストが得にくく、得られたとしても膜
厚依存性が大きいので実用的でない。一方１００ｎｍを
越すとクラックが生じ易くなる。記録層が主にＧｅ、Ｓ
ｂ、Ｔｅからなる場合はＧｅ含有量が２０％以上のとき
再結晶化が顕著となり本発明による記録法の効果が大き
くなり、Ｇｅ含有量が３０％以上のときはさらに効果は
顕著となる。The thickness is generally 10 nm to 100 n
It is selected in the range of m. If the thickness of the recording layer is less than 10 nm, it is difficult to obtain sufficient contrast, and even if it is obtained, the film thickness is highly dependent, which is not practical. On the other hand, if it exceeds 100 nm, cracks are likely to occur. The recording layer is mainly Ge, S
In the case of b and Te, recrystallization becomes remarkable when the Ge content is 20% or more, and the effect of the recording method according to the present invention becomes large, and the effect becomes more remarkable when the Ge content is 30% or more.
【００２６】Ｇｅ含有量が５０％以上になると書き変え
が難しくなる。記録層は、保護層で挟んで基板上に設
け、さらに反射層を設ける。更には紫外線硬化樹脂層等
を設けることが好ましい。記録層、保護層、反射層はス
パッタリング法などによって形成される。記録層用ター
ゲット、保護層用ターゲット、必要な場合には反射層材
料用ターゲットを同一真空チャンバー内に設置したイン
ライン装置で膜形成を行うことが各層間の酸化や汚染を
防ぐ点で望ましい。また、生産性の面からもすぐれてい
る。When the Ge content exceeds 50%, rewriting becomes difficult. The recording layer is provided on the substrate with the protective layer sandwiched between the recording layer and the reflective layer. Further, it is preferable to provide an ultraviolet curable resin layer or the like. The recording layer, the protective layer, and the reflective layer are formed by a sputtering method or the like. It is desirable to form a film by an in-line apparatus in which the target for recording layer, the target for protective layer, and the target for reflective layer material, if necessary, are installed in the same vacuum chamber in order to prevent oxidation and contamination between the layers. It is also excellent in terms of productivity.
【００２７】[0027]
【実施例】以下実施例をもって本発明を詳細に説明す
る。 実施例１ ポリカーボネート基板上に（ＺｎＳ）80（ＳｉＯ2）20
（ｍｏｌ．％）層を９０ｎｍ、ＳｉＯ2層を１３０ｎ
ｍ、（ＺｎＳ）80（ＳｉＯ2）20（ｍｏｌ．％）層を１
８０ｎｍ、Ｇｅ43Ｓｂ10Ｔｅ47（ａｔ．％）層を２５ｎ
ｍ、（ＺｎＳ）80（ＳｉＯ2）20（ｍｏｌ．％）層を１
９０ｎｍ、Ａｕ合金層を１００ｎｍ順次マグネトロンス
パッタリング法にて積層した。The present invention will be described in detail with reference to the following examples. Example 1 (ZnS) 80 (SiO 2 ) 20 on a polycarbonate substrate
(Mol.%) Layer 90 nm, SiO 2 layer 130 n
m, (ZnS) 80 (SiO 2 ) 20 (mol.%) layer
80 nm, Ge 43 Sb 10 Te 47 (at.%) Layer 25n
m, (ZnS) 80 (SiO 2 ) 20 (mol.%) layer
90 nm and 100 nm Au alloy layers were sequentially laminated by a magnetron sputtering method.
【００２８】さらに紫外線硬化樹脂層を４μｍ設けるこ
とによりディスクを作製した。このディスクを光ディス
ク評価装置（レーザー波長７８０ｎｍ、対物レンズ開口
数ＮＡ０．５５）を用い、以下のように繰り返し記録特
性を測定した。ディスクを１．４ｍ／ｓで回転させ、図
１に示すような本発明のパルス分割法で記録パワーＰ1
および消去パワーＰ2をそれぞれ１５ｍＷ、６ｍＷ、分
割パルスの間のレーザーパワーＰ3を０．８ｍＷとしＥ
ＦＭランダム信号を記録した。Further, a disc was prepared by providing an ultraviolet curable resin layer of 4 μm. This disk was repeatedly measured for recording characteristics as follows using an optical disk evaluation device (laser wavelength 780 nm, objective lens numerical aperture NA 0.55). The disk is rotated at 1.4 m / s, and the recording power P 1 is obtained by the pulse division method of the present invention as shown in FIG.
And erase power P 2 are 15 mW and 6 mW, respectively, and laser power P 3 between the divided pulses is 0.8 mW.
The FM random signal was recorded.
【００２９】結晶状態の反射率レベルをＲc、１１Ｔ信
号の反射率レベルをＲa、製膜直後のアモルファス状態
での反射率レベルをＲasとしたときの（Ｒc−Ｒa）／
（Ｒc−Ｒas）の値は０．７７であった。この値が大き
いほどアモルファスビットの幅が広い。また、繰り返し
記録回数と３Ｔビットジッタの関係を調べたところ、ジ
ッタが４０ｎｓｅｃ以下に保たれる記録回数は１５回で
あった。When the reflectance level in the crystalline state is Rc, the reflectance level of the 11T signal is Ra, and the reflectance level in the amorphous state immediately after film formation is Ras, (Rc-Ra) /
The value of (Rc-Ras) was 0.77. The larger this value, the wider the width of the amorphous bit. When the relationship between the number of repeated recordings and the 3T bit jitter was examined, the number of recordings in which the jitter was kept at 40 nsec or less was 15 times.
【００３０】なお結晶状態の反射率は６２％、１１Ｔビ
ット部の反射率は２９％であった。一方、従来のパルス
分割法を用い、記録、消去レーザーパワーは変化させ
ず、図２のような波形で記録した場合には、（Ｒc−Ｒ
a）／（Ｒc−Ｒas）の値は０．６７で、ジッタが４０ｎ
ｓｅｃ以下に保たれる記録回数は３回であった。実施例
１で使用した記録層組成は、繰り返し記録特性が実施例
２で用いた組成と比較すると劣っているが、信号振幅を
大きくとることができるという利点をもつ。The reflectance in the crystalline state was 62%, and the reflectance in the 11T bit portion was 29%. On the other hand, when the conventional pulse division method is used and the recording / erasing laser power is not changed and the waveform is recorded as shown in FIG. 2, (Rc-R
The value of a) / (Rc-Ras) is 0.67 and the jitter is 40n.
The number of recordings kept below sec was 3 times. The composition of the recording layer used in Example 1 is inferior to the composition used in Example 2 in the repetitive recording characteristics, but it has an advantage that a large signal amplitude can be obtained.
【００３１】実施例２ ポリカーボネート基板上に（ＺｎＳ）80（ＳｉＯ2）20
（ｍｏｌ．％）層を９０ｎｍ、ＳｉＯ2層を１３０ｎ
ｍ、（ＺｎＳ）80（ＳｉＯ2）20（ｍｏｌ．％）層を１
８０ｎｍ、Ｇｅ25Ｓｂ25Ｔｅ50（ａｔ．％）層を３０ｎ
ｍ、（ＺｎＳ）80（ＳｉＯ2）20（ｍｏｌ．％）層を１
８５ｎｍ、Ａｕ合金層を１００ｎｍ順次マグネトロンス
パッタリング法にて積層しさらに紫外線硬化樹脂層を４
μｍ設けることによりディスクを作製した。Example 2 (ZnS) 80 (SiO 2 ) 20 on a polycarbonate substrate
(Mol.%) Layer 90 nm, SiO 2 layer 130 n
m, (ZnS) 80 (SiO 2 ) 20 (mol.%) layer
80 nm, Ge 25 Sb 25 Te 50 (at.%) Layer 30 n
m, (ZnS) 80 (SiO 2 ) 20 (mol.%) layer
85 nm and Au alloy layer are sequentially stacked by magnetron sputtering method to 100 nm, and further 4 UV-curable resin layer.
A disk was prepared by providing a thickness of μm.
【００３２】このディスクを光ディスク評価装置（レー
ザー波長７８０ｎｍ、ＮＡ０．５５）を用い以下のよう
に繰り返し記録特性を測定した。ディスクを１．４ｍ／
ｓで回転させ、図１に示すような本発明のパルス分割法
で記録パワーＰ1および消去パワーＰ2をそれぞれ１５．
２ｍＷ、６．１ｍＷ、分割パルスの間のレーザーパワー
Ｐ3を０．８ｍＷとしＥＦＭランダム信号を記録した。The recording characteristics of this disk were repeatedly measured as follows using an optical disk evaluation device (laser wavelength 780 nm, NA 0.55). 1.4m / disk
rotated at s, the recording power P 1 and the erase power P 2 each 15 pulse division method of the present invention as shown in FIG.
An EFM random signal was recorded with 2 mW and 6.1 mW, the laser power P 3 between the divided pulses being 0.8 mW.
【００３３】結晶状態の反射率レベルをＲc、１１Ｔ信
号の反射率レベルをＲa、製膜直後のアモルファス状態
での反射率レベルをＲasとしたときの（Ｒc−Ｒa）／
（Ｒc−Ｒas）の値は０．８０であった。繰り返し記録
回数と３Ｔビットジッタの関係を調べたところ、ジッタ
が４０ｎｓｅｃ以下に保たれる記録回数は１００回であ
った。When the reflectance level in the crystalline state is Rc, the reflectance level of the 11T signal is Ra, and the reflectance level in the amorphous state immediately after film formation is Ras, (Rc-Ra) /
The value of (Rc-Ras) was 0.80. When the relationship between the number of repeated recordings and the 3T-bit jitter was examined, the number of recordings in which the jitter was kept at 40 nsec or less was 100 times.
【００３４】なお結晶状態の反射率は６４％、１１Ｔビ
ット部の反射率は４２％であった。一方、従来のパルス
分割法を用い、記録、消去レーザーパワーは変化させ
ず、図２のような波形で記録した場合には、（Ｒc−Ｒ
a）／（Ｒc−Ｒas）の値は０．７５で、ジッタが４０ｎ
ｓｅｃ以下に保たれる記録回数は１０回であった。The reflectance in the crystalline state was 64%, and the reflectance in the 11T bit portion was 42%. On the other hand, when the conventional pulse division method is used and the recording / erasing laser power is not changed and the waveform is recorded as shown in FIG. 2, (Rc-R
The value of a) / (Rc-Ras) is 0.75 and the jitter is 40n.
The number of recordings kept below sec was 10 times.
【００３５】[0035]
【発明の効果】本発明の記録パルスを用いることにより
従来の分割パルス法と比較し、記録レーザーパワーを変
化させずに信号振幅を大きくすることができる。さら
に、本発明の記録法は媒体の熱ダメージを小さくするた
め、相変化光ディスクの欠点である繰り返し記録による
特性劣化を小さくすることができる。By using the recording pulse of the present invention, the signal amplitude can be increased without changing the recording laser power, as compared with the conventional split pulse method. Further, since the recording method of the present invention reduces the heat damage to the medium, it is possible to reduce the characteristic deterioration due to repeated recording, which is a drawback of the phase change optical disk.
【００３６】本発明の効果は熱の逃げにくいディスク構
造、すなわち高記録感度媒体に対して特に顕著であり、
相変化光ディスクに望まれている高記録感度化に関して
重要な技術となる。また本発明の効果は、ＧｅＳｂＴｅ
系の場合、信号振幅を大きくすることができるＧｅ含有
量の多い組成に対して顕著である。The effect of the present invention is particularly remarkable for a disc structure in which heat does not easily escape, that is, a high recording sensitivity medium,
This is an important technique for increasing the recording sensitivity that is desired for a phase change optical disc. In addition, the effect of the present invention is that GeSbTe
In the case of the system, it is remarkable for the composition having a large Ge content that can increase the signal amplitude.
【００３７】したがって信号振幅を大きくする必要のあ
るＣＤ−ＲＯＭと互換性をもつ書換媒体の開発に関して
も重要な技術となる。Therefore, this is an important technique for the development of a rewritable medium compatible with a CD-ROM which requires a large signal amplitude.
【図１】 本発明の方法によるパルス形状を示す図面。FIG. 1 is a diagram showing a pulse shape according to the method of the present invention.
【図２】 従来の方法によるパルス形状を示す図面。FIG. 2 is a view showing a pulse shape according to a conventional method.
【図３】 本発明の方法によるパルス形状の他の一例を
示す図面。FIG. 3 is a view showing another example of pulse shapes according to the method of the present invention.
Ｐ1 記録パワー Ｐ2 消去パワー Ｐ3 分割パルスの間のレーザーパワーP 1 recording power P 2 erasing power P 3 laser power between divided pulses
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｇ１１Ｂ 7/24 ５１１ 7215−5Ｄ ５３７ Ｚ 7215−5Ｄ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical display location G11B 7/24 511 7215-5D 537 Z 7215-5D
Claims (6)
移型光記録層、誘電体保護層、反射層を順に積層してな
る光学的情報記録用媒体に、少なくとも記録レーザーパ
ワーＰ1とＰ1より小さい消去レーザーパワーＰ2を用い
て１ビームオーバーライト記録する方法であって、ビッ
トを形成する記録パルスを該ビット長よりも短い複数の
パルスに分割し、分割した各パルスのレーザーパワーは
記録レーザーパワーＰ1とし、分割したパルスの間のレ
ーザーパワーを消去レーザーパワーＰ2の１／２より小
さくゼロでないレーザーパワーＰ3としたことを特徴と
する記録方法。1. An optical information recording medium comprising a substrate and at least a dielectric protective layer, a phase transition type optical recording layer, a dielectric protective layer, and a reflective layer, which are laminated in this order, and at least recording laser powers P 1 and P. a method for one-beam overwrite recording using less than one erasing laser power P 2, a recording pulse for forming a bit is divided into a plurality of pulses shorter than the bit length, the laser power of each divided pulse A recording method wherein the recording laser power P 1 is set and the laser power between the divided pulses is set to a laser power P 3 which is less than 1/2 of the erasing laser power P 2 and is not zero.
移型光記録層、誘電体保護層、反射層を順に積層してな
る光学的情報記録用媒体に、少なくとも記録レーザーパ
ワーＰ1とＰ1より小さい消去レーザーパワーＰ2を用い
て１ビームオーバーライト記録する方法であって、ビッ
トを形成する記録パルスを該ビット長よりも短い複数の
パルスに分割し、分割した各パルスのレーザーパワーは
記録レーザーパワーＰ1とし、分割したパルスの間のレ
ーザーパワーは、消去レーザーパワーＰ2の１／２より
小さくゼロでないレーザーパワーＰ3と消去レーザーパ
ワーＰ2近傍のレーザーパワーとで構成することを特徴
とする記録方法。2. An optical information recording medium in which at least a dielectric protective layer, a phase transition type optical recording layer, a dielectric protective layer, and a reflective layer are sequentially laminated on a substrate, and at least recording laser powers P 1 and P. a method for one-beam overwrite recording using less than one erasing laser power P 2, a recording pulse for forming a bit is divided into a plurality of pulses shorter than the bit length, the laser power of each divided pulse The recording laser power P 1 is set, and the laser power between the divided pulses is composed of a laser power P 3 which is less than 1/2 of the erase laser power P 2 and is not zero and a laser power near the erase laser power P 2. Characteristic recording method.
厚が１００〜５００ｎｍであることを特徴とする請求項
１に記載の記録方法。3. The recording method according to claim 1, wherein the film thickness of the dielectric protective layer between the recording layer and the reflective layer is 100 to 500 nm.
厚が１００〜５００ｎｍであることを特徴とする請求項
２に記載の記録方法。4. The recording method according to claim 2, wherein the thickness of the dielectric protective layer between the recording layer and the reflective layer is 100 to 500 nm.
ｅからなり、Ｇｅの含有量が２０〜５０ａｔ．％である
ことを特徴とする請求項１に記載の記録方法。5. The phase transition type optical recording layer is mainly composed of Ge, Sb, T.
e, and the Ge content is 20 to 50 at. The recording method according to claim 1, wherein the recording method is%.
からなり、Ｇｅの含有量が２０〜５０ａｔ．％であるこ
とを特徴とする請求項２に記載の記録方法。6. The phase transition type optical recording layer is mainly Ge, Sb, Te.
And a Ge content of 20 to 50 at. %, And the recording method according to claim 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6318571A JPH08180414A (en) | 1994-12-21 | 1994-12-21 | Optical information recording method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6318571A JPH08180414A (en) | 1994-12-21 | 1994-12-21 | Optical information recording method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08180414A true JPH08180414A (en) | 1996-07-12 |
Family
ID=18100625
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6318571A Pending JPH08180414A (en) | 1994-12-21 | 1994-12-21 | Optical information recording method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08180414A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998009823A1 (en) * | 1996-09-09 | 1998-03-12 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium, its manufacturing method, optical information recording/reproducing method and optical information recorder/reproducer |
| US6811949B2 (en) | 1996-10-04 | 2004-11-02 | Mitsubishi Chemical Corporation | Optical information recording medium and optical recording method |
| US6842415B2 (en) | 1997-09-09 | 2005-01-11 | Hitachi, Ltd. | Information recording method and apparatus with suppressed mark edge jitters |
-
1994
- 1994-12-21 JP JP6318571A patent/JPH08180414A/en active Pending
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998009823A1 (en) * | 1996-09-09 | 1998-03-12 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium, its manufacturing method, optical information recording/reproducing method and optical information recorder/reproducer |
| US6229785B1 (en) | 1996-09-09 | 2001-05-08 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium, its manufacturing method, optical information recording/reproducing method and optical information recorder/reproducer |
| US6811949B2 (en) | 1996-10-04 | 2004-11-02 | Mitsubishi Chemical Corporation | Optical information recording medium and optical recording method |
| US6842415B2 (en) | 1997-09-09 | 2005-01-11 | Hitachi, Ltd. | Information recording method and apparatus with suppressed mark edge jitters |
| KR100467917B1 (en) * | 1997-09-09 | 2005-01-24 | 가부시끼가이샤 히다치 세이사꾸쇼 | Information recording method and information recording apparatus |
| US7012871B2 (en) | 1997-09-09 | 2006-03-14 | Hitachi, Ltd. | Information recording method and apparatus with suppressed mark edge jitters |
| US7042823B2 (en) | 1997-09-09 | 2006-05-09 | Hitachi, Ltd. | Information recording method and apparatus with suppressed mark edge jitters |
| US7417933B2 (en) | 1997-09-09 | 2008-08-26 | Hitachi, Ltd. | Information recording method and apparatus with suppressed mark edge jitters |
| US7684301B2 (en) | 1997-09-09 | 2010-03-23 | Hitachi, Ltd. | Information recording method and apparatus with suppressed mark edge jitters |
| US7852727B2 (en) | 1997-09-09 | 2010-12-14 | Hitachi, Ltd. | Information recording method and apparatus with suppressed mark edge jitters |
| US7907490B2 (en) | 1997-09-09 | 2011-03-15 | Hitachi, Ltd. | Information recording method and apparatus with suppressed mark edge jitters |
| US7907491B2 (en) | 1997-09-09 | 2011-03-15 | Hitachi, Ltd. | Information recording method and apparatus with suppressed mark edge jitters |
| US7911910B2 (en) | 1997-09-09 | 2011-03-22 | Hitachi, Ltd. | Information recording method and apparatus with suppressed mark edge jitters |
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