JPH09326135A - Optical information recording medium and its recording and reproducing method - Google Patents
Optical information recording medium and its recording and reproducing methodInfo
- Publication number
- JPH09326135A JPH09326135A JP8144656A JP14465696A JPH09326135A JP H09326135 A JPH09326135 A JP H09326135A JP 8144656 A JP8144656 A JP 8144656A JP 14465696 A JP14465696 A JP 14465696A JP H09326135 A JPH09326135 A JP H09326135A
- Authority
- JP
- Japan
- Prior art keywords
- recording
- thin film
- ratio
- atom
- optical information
- 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.)
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- Optical Recording Or Reproduction (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、基板上に形成され
た相変化材料薄膜にレーザービーム等の高エネルギービ
ームを照射することにより、信号品質の高い情報信号を
記録・再生することのできる光学的情報記録媒体及びそ
の記録・再生方法に関するものである。The present invention relates to an optical system capable of recording / reproducing an information signal having high signal quality by irradiating a phase change material thin film formed on a substrate with a high energy beam such as a laser beam. Information recording medium and its recording / reproducing method.
【０００２】[0002]
【従来の技術】レーザー光線を利用して高密度な情報の
記録・再生を行う技術はよく知られている。このような
記録再生に用いる記録媒体としては、基板上にＴｅとＴ
ｅＯ2の混合物であるＴｅＯx （０＜ｘ＜２）を主成分
とする材料薄膜を設けたものが提案されている（特開昭
５０−４６３１７号公報、米国特許第３９７１８７４号
明細書）。このような記録媒体は再生用の光ビームの照
射において透過率変化を大きく得ることができる。2. Description of the Related Art A technique for recording / reproducing high density information by using a laser beam is well known. As a recording medium used for such recording and reproduction, Te and T on a substrate are used.
It has been proposed that a material thin film containing TeO x (0 <x <2), which is a mixture of eO 2 , as a main component is provided (Japanese Patent Laid-Open No. 50-46317 and US Pat. No. 3,971,874). In such a recording medium, it is possible to obtain a large change in transmittance upon irradiation with a reproduction light beam.
【０００３】しかし、記録、再生装置の小型化、簡易化
を図る場合に使用し得るレーザー光源の出力には限度が
あり、小型の出力２０ｍＷ以内の半導体レーザー発信装
置等を使用して記録・再生を行う場合、従来のＴｅＯx
（０＜ｘ＜２）を主成分とする薄膜を有する記録媒体で
は感度が不十分である。また、記録された情報を再生し
ても十分な反射光量変化が得られない。However, there is a limit to the output of the laser light source that can be used for downsizing and simplification of the recording / reproducing apparatus, and recording / reproducing is performed by using a small semiconductor laser emitting device having an output of 20 mW or less. Conventional TeO x
A recording medium having a thin film containing (0 <x <2) as a main component has insufficient sensitivity. Moreover, even if the recorded information is reproduced, a sufficient change in the amount of reflected light cannot be obtained.
【０００４】さらに、ＴｅＯx においては、記録後信号
が飽和するまで、すなわち記録薄膜中のレーザー光照射
部の結晶化が十分進むまでに若干の時間を要する。これ
は、データをディスクに記録して一回転後にそのデータ
を検証するコンピューター用データファイルの場合など
のように高速な応答性が要求される記録媒体としては不
適当である。Further, in TeO x , it takes some time until the signal is saturated after recording, that is, until the crystallization of the laser light irradiation portion in the recording thin film is sufficiently advanced. This is unsuitable as a recording medium that requires high-speed response, such as a computer data file in which data is recorded on a disk and the data is verified after one rotation.
【０００５】そこで、上記欠点を補うためにＴｅＯx に
第３の元素として例えばＰｄを添加する方法が提案され
ている（特開昭６１−６８２９６号公報）。ＰｄはＴｅ
Ｏx薄膜中においてレーザー光照射時にＴｅの結晶成長
を促進する結晶核のような働きをしていると考えられて
おり、これによって結晶性のより進んだＴｅの結晶粒が
高速で生成される。その結果として、より大きな再生光
の反射率変化、すなわち高いＣ／Ｎ比が得られる。ま
た、ＴｅＯx はＰｄを添加することによって光の吸収効
率が大きくなるため感度も向上する。さらに、Ｐｄはそ
の高い耐酸化性のために、ＴｅＯx 薄膜の優れた耐湿性
を損なうことがない。Therefore, a method has been proposed in which TeO x is added with, for example, Pd as a third element in order to make up for the above-mentioned drawbacks (Japanese Patent Laid-Open No. 61-68296). Pd is Te
It is considered that the O x thin film acts like a crystal nucleus that promotes the crystal growth of Te when irradiated with laser light, and thereby Te crystal grains with more advanced crystallinity are generated at high speed. . As a result, a larger reflectance change of the reproduction light, that is, a higher C / N ratio can be obtained. Further, TeO x increases the light absorption efficiency by adding Pd, and therefore the sensitivity is also improved. Further, Pd does not impair the excellent moisture resistance of the TeO x thin film due to its high oxidation resistance.
【０００６】しかし、近年の情報の大容量化に伴いさら
なる記録密度の向上が要求されるようになってきてお
り、短波長・高ＮＡの光学系を用いた高密度記録に対応
できる記録媒体を開発することが必要となってきてい
る。However, with the recent increase in the capacity of information, further improvement in the recording density is required, and a recording medium that can be used for high density recording using an optical system with a short wavelength and a high NA is required. Development is needed.
【０００７】[0007]
【発明が解決しようとする課題】同じ光学系を用いてよ
り高密度な記録・再生をする場合に、記録薄膜の熱伝導
率が適当な範囲にないと、十分な記録特性が得られない
と考えられる。すなわち、記録薄膜の熱伝導率が低すぎ
るとレーザー光で加熱された部分から熱が拡がりにく
く、記録パワーを大きくしても記録マークが大きくなら
ないため感度が悪く、Ｃ／Ｎ比も低くなってしまう傾向
がある。逆に記録薄膜の熱伝導率が高すぎると、レーザ
ー光で加熱された部分から熱が拡がりやすく、少し記録
パワーを大きくすれば記録マークが大きくなるため感度
は良く、Ｃ／Ｎ比も高くなる傾向がある。しかし、記録
マークのエッジがぼやけやすく、レーザー光の記録パワ
ーを最適なパワーより少しでもあげると隣接マークどう
しがつながりはじめ、Ｃ／Ｎ比が低下してしまうので、
パワーマージンが狭く実用上問題がある。これは同じ光
学系での記録・再生においてもマーク間隔を狭くしてよ
り高密度になるほど顕著であると考えられる。When recording / reproducing at a higher density using the same optical system, sufficient recording characteristics cannot be obtained unless the thermal conductivity of the recording thin film is within an appropriate range. Conceivable. That is, if the thermal conductivity of the recording thin film is too low, the heat is less likely to spread from the portion heated by the laser light, and the recording mark does not increase even if the recording power is increased, so the sensitivity is poor and the C / N ratio is also low. Tend to end up. On the contrary, if the thermal conductivity of the recording thin film is too high, heat easily spreads from the portion heated by the laser beam, and if the recording power is increased a little, the recording mark becomes large, so that the sensitivity is good and the C / N ratio becomes high. Tend. However, the edges of the recording marks are easily blurred, and if the recording power of the laser light is raised even more than the optimum power, adjacent marks will start to connect and the C / N ratio will decrease.
The power margin is narrow and there is a practical problem. This is considered to be more remarkable as the mark spacing becomes narrower and the density becomes higher even in recording / reproducing with the same optical system.
【０００８】また、高いＣ／Ｎ比が得られていても実際
にビットエラーが少ないとは限らない。例えば、前記し
た記録薄膜の熱伝導率が高い場合には記録マーク間で熱
的な干渉を生じやすく、その結果、検出される記録マー
クの位置が変動してしまい、反射率変化やＣ／Ｎ比が高
くてもビットエラーが多いなどといったケースが考えら
れる。そこで、Ｃ／Ｎ比には現れない信号品質の評価方
法として、すなわちこのビットエラーの多さの一つの指
標としてベリファイという評価項目がある。ベリファイ
とは、記録されたデータを再生したとき規定値よりビッ
トエラーが少なく、エラーコレクションコードによりあ
らかじめ設けられたエラー訂正領域内においてエラー訂
正が可能であるかどうかを検証することであり、エラー
訂正が可能である場合を「ベリファイ可能」という。Even if a high C / N ratio is obtained, the number of bit errors is not always small. For example, when the thermal conductivity of the recording thin film is high, thermal interference is likely to occur between the recording marks, and as a result, the position of the detected recording mark fluctuates, causing a change in reflectance or C / N. It is possible that there are many bit errors even if the ratio is high. Therefore, as an evaluation method of signal quality that does not appear in the C / N ratio, that is, as one index of the number of bit errors, there is an evaluation item called verify. Verify is to verify whether or not there are fewer bit errors than the specified value when the recorded data is played back, and whether error correction is possible within the error correction area provided in advance by the error correction code. If it is possible, it is said that "verification is possible".
【０００９】特に上記記録薄膜の熱伝導率が高すぎる場
合においては、マーク間の熱干渉によるマーク位置変動
のため、反射率変化やＣ／Ｎ比が高くてもビットエラー
が多く、ベリファイ不可能になる可能性がある。In particular, when the thermal conductivity of the recording thin film is too high, the mark position varies due to the thermal interference between the marks, so that even if the reflectance change or the C / N ratio is high, there are many bit errors and the verification is impossible. Could be.
【００１０】上記ＴｅＯx にＰｄを添加した従来例（特
開昭６１−６８２９６号公報）の記録条件は、レーザー
波長８３０ｎｍ、波長限界０．８μｍ、回転数１８００
ｒｐｍ、記録位置（半径）７５ｍｍ、記録周波数５ＭＨ
ｚと記されている。これは昭和６１年というこの発明当
時の技術的背景からＰＰＭ記録であると考えられるの
で、上記半径位置及び回転数から計算した線速度１４．
１ｍ／ｓの条件においては、最短マーク間隔２．８３μ
ｍ、ビット長ｂは１．８９μｍに相当する。また、ここ
でいう波長限界０．８μｍとは、レーザー光のビーム強
度がガウス分布すると近似し、ビーム強度がスポット中
心の１／２となる直径を波長限界と定義し、レンズＮＡ
を０．５として計算したものと考えられる。これはレー
ザー光のビーム強度がガウス分布すると近似し、ビーム
強度がスポット中心の１／ｅとなる直径をスポット径ｄ
とした場合、スポット径ｄは１．０１μｍとなる。以上
より、ビット長ｂのスポット径ｄに対する比ｂ／ｄが
１．８７となる。The recording conditions of the conventional example (Japanese Patent Laid-Open No. 61-68296) in which Pd is added to TeO x are as follows: laser wavelength 830 nm, wavelength limit 0.8 μm, rotation speed 1800.
rpm, recording position (radius) 75 mm, recording frequency 5 MH
It is written as z. Since this is considered to be a PPM record from the technical background at the time of the invention of 1986, the linear velocity calculated from the above radial position and rotation speed was 14.
Under the condition of 1 m / s, the shortest mark interval is 2.83μ.
m and bit length b correspond to 1.89 μm. The wavelength limit of 0.8 μm is approximated to a Gaussian distribution of the beam intensity of laser light, and the diameter at which the beam intensity is 1/2 of the spot center is defined as the wavelength limit.
Is considered to be calculated as 0.5. This is approximated to the Gaussian distribution of the beam intensity of the laser light, and the diameter at which the beam intensity is 1 / e of the spot center is the spot diameter d.
In that case, the spot diameter d is 1.01 μm. From the above, the ratio b / d of the bit length b to the spot diameter d is 1.87.
【００１１】上記従来例（特開昭６１−６８２９６号公
報）においては、ｂ／ｄ＝１．８７の条件下で５０ｄＢ
以上、組成によっては６０ｄＢ程度の高いＣ／Ｎ比が得
られている。しかし近年、記録媒体としては容量６５０
ＭＢのＣＤ−ＲＯＭ等と互角の記録容量が要求されるよ
うになってきており、この容量をＣＤサイズの面積に波
長７８０ｎｍ、ＮＡ０．５といった技術的に熟成され、
製造コスト的にも適当な光学系を用いて記録する場合、
ｂ／ｄ＝０．９２となる。これは上記従来例に比べて格
段にｂ／ｄが小さく、上記従来例の記録媒体がこの記録
マーク間の十分なコントラストを得ることが困難な、よ
り厳しい条件においても良好な記録特性を示すとは限ら
ない。したがってｂ／ｄの小さいより高密度な記録・再
生においてＣ／Ｎ比が高く、ビットエラーの少ない良好
な記録特性を広いパワーマージンにおいて得るために
は、これに適する記録薄膜の組成範囲を見直す必要があ
ると考えられる。In the above conventional example (Japanese Patent Laid-Open No. 61-68296), 50 dB under the condition of b / d = 1.87.
As described above, depending on the composition, a high C / N ratio of about 60 dB is obtained. However, in recent years, a recording medium has a capacity of 650.
There is a demand for recording capacity that is equal to that of MB CD-ROMs, etc., and this capacity has been technically matured such that the CD size area has a wavelength of 780 nm and NA 0.5.
When recording using an appropriate optical system in terms of manufacturing cost,
b / d = 0.92. This is because b / d is remarkably smaller than that of the above-mentioned conventional example, and it is difficult for the recording medium of the above-mentioned conventional example to obtain a sufficient contrast between the recording marks. Not necessarily. Therefore, in order to obtain good recording characteristics with a high C / N ratio and a small bit error in a wide power margin in high-density recording / reproducing with a small b / d, it is necessary to review the composition range of the recording thin film suitable for this. It is thought that there is.
【００１２】本発明は、前記従来の問題を解決するた
め、記録ビット長ｂのスポット径ｄに対する比ｂ／ｄの
小さい情報の記録・再生においてＣ／Ｎ比が高く、ビッ
トエラーの少ない良好な記録特性が広いパワーマージン
で得られる光学的情報記録媒体及びその記録・再生方法
を提供することを目的とするものである。In order to solve the above-mentioned conventional problems, the present invention has a high C / N ratio in recording / reproducing information having a small ratio b / d of the recording bit length b to the spot diameter d, and has a good bit error. It is an object of the present invention to provide an optical information recording medium having a wide recording power and a wide power margin, and a recording / reproducing method thereof.
【００１３】[0013]
【課題を解決するための手段】前記目的を達成するた
め、本発明の光学的情報記録媒体は、透明基板上に、少
なくとも光ビームの照射により光学的特性の異なる状態
への変化を呈する材料からなる記録薄膜を有し、前記記
録薄膜がＴｅ、Ｏ及びＰｄを主成分とし、前記記録薄膜
中に含有されるＴｅ原子の割合が２０〜７０atom％、Ｏ
原子の割合が２５〜４５atom％、かつＰｄ原子の割合が
５〜３５atom％の組成割合の範囲内にあることを特徴と
する。In order to achieve the above-mentioned object, the optical information recording medium of the present invention comprises a transparent substrate made of a material exhibiting a change in optical characteristics to at least a different state upon irradiation with a light beam. The recording thin film is mainly composed of Te, O and Pd, and the proportion of Te atoms contained in the recording thin film is 20 to 70 atom%, O.
It is characterized in that the proportion of atoms is in the range of 25 to 45 atom% and the proportion of Pd atoms is in the range of 5 to 35 atom%.
【００１４】上記光学的情報記録媒体においては、上記
記録薄膜中に含有されるＴｅ原子の割合が３０〜６５at
om％、Ｏ原子の割合が３０〜４０atom％、かつＰｄ原子
の割合が５〜３０atom％の組成割合の範囲内にあること
をがより好ましい。In the above optical information recording medium, the proportion of Te atoms contained in the recording thin film is 30 to 65 at.
It is more preferable that the composition ratios of om% and O atom are 30 to 40 atom%, and Pd atom ratio is 5 to 30 atom%.
【００１５】また、上記光学的情報記録媒体において
は、上記記録薄膜の膜厚が２０〜２００ｎｍの範囲にあ
ることが好ましい。また、上記光学的情報記録媒体にお
いては、上記記録薄膜の基板側及び基板と反対側のいず
れか一方あるいは両方に誘電体材料からなる保護層を有
することが好ましい。In the above optical information recording medium, it is preferable that the film thickness of the recording thin film is in the range of 20 to 200 nm. Further, in the above optical information recording medium, it is preferable that a protective layer made of a dielectric material is provided on either or both of the substrate side and the opposite side of the recording thin film.
【００１６】また、上記光学的情報記録媒体において
は、上記記録薄膜の基板と反対側に反射層を有すること
が好ましい。また、上記課題を解決するため、本発明の
光学的情報記録媒体の記録・再生方法は、透明基板上
に、少なくとも光ビームの照射により光学的特性の異な
る状態への変化を呈する材料からなる記録薄膜を有し、
前記記録薄膜がＴｅ、Ｏ及びＰｄを主成分とし、前記記
録薄膜中に含有される前記Ｏ原子の割合が２５〜４５at
om％、かつ前記Ｐｄ原子の割合が５〜３５atom％の組成
割合の範囲内にある光学的情報記録媒体に情報信号を、
前記光ビームが対物レンズを通して前記光学的情報記録
媒体に照射される際にビーム強度がガウス分布すると近
似した場合、ビーム強度がスポット中心の１／ｅとなる
直径すなわちスポット径をｄ、記録ビット長をｂとし
て、前記ビット長ｂの前記スポット径ｄに対する比ｂ／
ｄが１．０以下の条件で記録・再生することを特徴とす
る。The optical information recording medium preferably has a reflective layer on the side of the recording thin film opposite to the substrate. Further, in order to solve the above-mentioned problems, a recording / reproducing method of an optical information recording medium of the present invention is a recording made of a material exhibiting a change in optical characteristics to a different state at least on irradiation with a light beam on a transparent substrate. Has a thin film,
The recording thin film contains Te, O and Pd as main components, and the proportion of the O atoms contained in the recording thin film is 25 to 45 at.
om% and an information signal to an optical information recording medium in which the proportion of Pd atoms is in the range of composition proportion of 5 to 35 atom%,
When it is approximated that the beam intensity is Gaussian distributed when the light beam is applied to the optical information recording medium through the objective lens, the diameter at which the beam intensity becomes 1 / e of the spot center, that is, the spot diameter is d and the recording bit length is Where b is the ratio of the bit length b to the spot diameter d, b /
Recording and reproduction are performed under the condition that d is 1.0 or less.
【００１７】上記光学的情報記録媒体の記録・再生方法
において、上記記録薄膜中に含有される上記Ｏ原子の割
合が３０〜４０atom％、かつ上記Ｐｄ原子の割合が５〜
３０atom％の組成割合の範囲内にあり、上記ビット長ｂ
の上記スポット径ｄに対する比ｂ／ｄが０．８以下であ
ることがより好ましい。In the recording / reproducing method of the optical information recording medium, the proportion of the O atom contained in the recording thin film is 30 to 40 atom%, and the proportion of the Pd atom is 5 to 5.
Within the composition ratio range of 30 atom%, the bit length b
It is more preferable that the ratio b / d to the spot diameter d is 0.8 or less.
【００１８】[0018]
【発明の実施の形態】以下、本発明の実施の形態につい
て図面を用いて説明する。図１はＴｅ−Ｏ−Ｐｄの３元
系の組成図であり、図１においてＡ、Ｂ、Ｃ、Ｄで囲ま
れた領域、またはＥ、Ｆ、Ｇ、Ｈで囲まれた領域は本発
明による光学的情報記録媒体の記録薄膜の組成範囲を示
す。図２は本発明による光学的情報記録媒体の構成断面
図である。図２において１は透明なディスク基板、２は
記録薄膜でＴｅ−Ｏ−Ｐｄを主成分とする合金材料、３
はオーバーコート層である。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a composition diagram of a Te—O—Pd ternary system. In FIG. 1, the region surrounded by A, B, C, D or the region surrounded by E, F, G, H is the present invention. 2 shows the composition range of the recording thin film of the optical information recording medium. FIG. 2 is a sectional view showing the configuration of the optical information recording medium according to the present invention. In FIG. 2, 1 is a transparent disk substrate, 2 is a recording thin film, an alloy material containing Te-O-Pd as a main component, 3
Is an overcoat layer.
【００１９】透明基板１の材料としては、ポリカーボネ
イト樹脂、ポリメチルメタクリレート樹脂、ポリオレフ
ィン樹脂、ガラス等を用いることができる。透明基板１
の厚さは特に限定されないが、０．１〜１．５ｍｍ程度
のものを用いることができる。As the material of the transparent substrate 1, polycarbonate resin, polymethylmethacrylate resin, polyolefin resin, glass or the like can be used. Transparent substrate 1
The thickness is not particularly limited, but a thickness of about 0.1 to 1.5 mm can be used.
【００２０】記録薄膜２は真空蒸着法、スパッタリング
法、イオンプレーティング法、ＣＶＤ（Chemical Vapor
Deposition）法、ＭＢＥ（Molecukar Beam Epitaxy）
法等によって形成することができる。The recording thin film 2 is formed by vacuum vapor deposition, sputtering, ion plating, CVD (Chemical Vapor).
Deposition) method, MBE (Molecukar Beam Epitaxy)
It can be formed by a method or the like.
【００２１】また本発明の光学的情報記録媒体は、図２
に示すように紫外線硬化性樹脂でオーバーコートして単
板ディスクとするか、図３に示すように紫外線硬化性樹
脂またはホットメルトタイプの接着剤４で貼り合わせて
両面ディスクとしても使える。The optical information recording medium of the present invention is shown in FIG.
It can be used as a double-sided disc by overcoating with a UV-curable resin as shown in Fig. 3 to form a single disk, or by laminating it with a UV-curable resin or a hot-melt type adhesive 4 as shown in Fig. 3.
【００２２】また、本発明の光学的情報記録媒体は、記
録膜の熱的損傷によるノイズの増加を抑制する等の目的
と必要に応じて、図４に示すように例えばＺｎＳ−Ｓｉ
Ｏ2混合材料等の誘電体保護層５を記録薄膜の基板側及
び基板と反対側のいずれか一方、また両方に設けること
もできる。Further, the optical information recording medium of the present invention has, for example, ZnS-Si as shown in FIG. 4 for the purpose of suppressing the increase of noise due to thermal damage of the recording film and as necessary.
The dielectric protective layer 5 such as an O 2 mixed material may be provided on either the substrate side or the opposite side of the recording thin film, or both.
【００２３】また、本発明の光学的情報記録媒体は、吸
収率向上、反射率向上、記録薄膜の熱負荷の軽減等の目
的で必要に応じて、図５に示すように例えばＡｕ、Ａｌ
−Ｃｒ等の金属、または合金材料からなる反射層６を記
録薄膜の基板と反対側に設けることもできる。Further, the optical information recording medium of the present invention, as shown in FIG. 5, is made of, for example, Au or Al as necessary for the purpose of improving the absorptance, improving the reflectance, reducing the thermal load on the recording thin film, and the like.
The reflective layer 6 made of a metal such as -Cr or an alloy material may be provided on the opposite side of the recording thin film from the substrate.
【００２４】図６は本発明による光学的情報記録媒体の
記録・再生を行うための装置の概略図である。記録を行
う場合には、半導体レーザー９の出力を入力信号（矢印
１８）に応じてピークパワー及びそれよりも弱いバイア
スパワーの２値間で変調する。半導体レーザーを出たレ
ーザービーム１０はコリメータレンズ１０で集光されて
平行光線となり、ビームスプリッター１２、λ／４波長
板１３、対物レンズ７を通じて光ディスク１７上に、対
物レンズをボイスコイル１６で上下に動かすことによっ
てフォーカシングされる。光ディスクはターンテーブル
１４上に固定され、モーター８によって回転され、情報
信号の記録が行われる。この情報信号を再生する場合に
は、記録時よりも半導体レーザーの出力を弱めた一定パ
ワーの連続光を記録時と同じように光ディスクに照射
し、その反射光を検出器１５に入射させ、その反射光量
変化を再生信号（再生出力：矢印１９）として検出す
る。FIG. 6 is a schematic view of an apparatus for recording / reproducing an optical information recording medium according to the present invention. When recording is performed, the output of the semiconductor laser 9 is modulated between two values of the peak power and the bias power weaker than that according to the input signal (arrow 18). The laser beam 10 emitted from the semiconductor laser is condensed by the collimator lens 10 to be a parallel light beam, and is passed through the beam splitter 12, the λ / 4 wavelength plate 13 and the objective lens 7 onto the optical disk 17, and the objective lens is moved up and down by the voice coil 16. Focused by moving. The optical disk is fixed on the turntable 14 and rotated by the motor 8 to record an information signal. When reproducing this information signal, continuous light of a constant power, which weakens the output of the semiconductor laser as compared with that during recording, is applied to the optical disk in the same manner as during recording, and the reflected light is made incident on the detector 15, and The change in the amount of reflected light is detected as a reproduction signal (reproduction output: arrow 19).
【００２５】（実施の形態１）ポリカーボネイト樹脂か
らなる厚さ１．２ｍｍ、溝ピッチ１．２μｍのレーザー
案内用溝の設けられた透明基板上に、Ｔｅ、Ｏ、Ｐｄか
らなる記録薄膜を、Ｔｅ及びＰｄの単体材料ターゲット
を用いて、スパッタガスＡｒ及びＯ2 の雰囲気中で、ス
パッタリング法にて約１３０ｎｍ積層した。その表面に
紫外線硬化性樹脂（商品名”ダイキュアクリアＳＤ−１
０１”、大日本インキ化学工業社製）でオーバーコート
した単板のディスクＮｏ．１〜２０を作成した。これら
は記録特性の記録薄膜組成に対する依存性を調べるため
にその組成を変化させたディスクであり、表１に各ディ
スクの記録薄膜のオージェ電子分光法（以下ＡＥＳと略
す）による元素分析結果を示す。また、この結果に基づ
いて各ディスクの組成を図１に示した。(Embodiment 1) A recording thin film made of Te, O, and Pd is formed on a transparent substrate made of polycarbonate resin having a thickness of 1.2 mm and a groove pitch of 1.2 μm and provided with laser guide grooves. Using a single material target of Pd and Pd, a stack of about 130 nm was formed by a sputtering method in an atmosphere of sputtering gas Ar and O 2 . UV-curable resin on the surface (brand name "Dicure Clear SD-1"
01 ", manufactured by Dainippon Ink and Chemicals, Inc.) was used to make single-plate discs Nos. 1 to 20. These discs had different compositions in order to examine the dependence of the recording characteristics on the recording thin film composition. The results of elemental analysis of the recording thin film of each disk by Auger electron spectroscopy (hereinafter abbreviated as AES) are shown in Table 1. The composition of each disk is shown in FIG.
【００２６】[0026]
【表１】 [Table 1]
【００２７】上記ディスクに対し、波長７８０ｎｍ、Ｎ
Ａ０．５の光学系を用い、線速度５．３ｍ／ｓ（回転数
２７００ｒｐｍ）でビット長０．９５μｍのＰＰＭ記録
を行った。この条件では、レーザー光のビーム強度がガ
ウス分布すると近似し、ビーム強度がスポット中心の１
／ｅとなる直径をスポット径ｄと定義した場合、スポッ
ト径ｄ＝０．９５μｍとなり、ビット長ｂのスポット径
ｄに対する比ｂ／ｄ＝１．０となる。With respect to the above disc, a wavelength of 780 nm, N
Using an A0.5 optical system, PPM recording with a bit length of 0.95 μm was performed at a linear velocity of 5.3 m / s (rotation speed 2700 rpm). Under this condition, it is approximated that the beam intensity of the laser light is Gaussian distributed, and the beam intensity is 1
When the diameter of / e is defined as the spot diameter d, the spot diameter d = 0.95 μm, and the ratio of the bit length b to the spot diameter d is b / d = 1.0.
【００２８】この条件で、２．０〜２０．０ｍＷの範囲
（０．５ｍＷ刻み）の記録パワー（ピークパワー）で３
Ｔ周期の単一信号及び２−７ＲＬＬランダム信号を未記
録のトラックに１回記録して、それぞれＣ／Ｎ比及びベ
リファイを評価した。バイアスパワーは再生パワーと同
じく１ｍＷであった。なお、Ｃ／Ｎ比はふつう記録して
数分後程度のものを測定するが、記録薄膜の組成によっ
ては記録後信号が飽和するまで、すなわち記録薄膜中の
レーザー光照射部の結晶化が十分進むまでに若干の時間
を要する場合があるので、データをディスクに記録して
一回転後（２２ｍｓ後）にＣ／Ｎ比も測定した。Under this condition, the recording power (peak power) in the range of 2.0 to 20.0 mW (in increments of 0.5 mW) is 3
A single signal with a T period and a 2-7 RLL random signal were recorded once on an unrecorded track to evaluate the C / N ratio and the verify, respectively. The bias power was 1 mW like the reproducing power. The C / N ratio is usually measured several minutes after recording, but depending on the composition of the recording thin film, crystallization of the laser light irradiation part in the recording thin film is sufficient until the signal is saturated after recording. Since it may take some time to proceed, the data was recorded on the disk, and the C / N ratio was also measured after one rotation (after 22 ms).
【００２９】表１は各ディスクＮｏ．１〜２０の評価結
果で、記録して２２ｍｓ後及び数分後のＣ／Ｎ比の最高
値及びベリファイ可能な記録パワーマージンの幅を示し
てある。表１によると、記録薄膜中Ｏ原子が２５atom％
以下の領域では記録薄膜の熱伝導率が高すぎるため、Ｃ
／Ｎ比こそ高いが、ベリファイ可能な記録パワーマージ
ンが非常に狭いか、または無く、実用上問題がある。こ
れに対し記録薄膜中Ｏ原子が２５atom％以上の領域では
記録薄膜の熱伝導率が低くなるため、比較的Ｃ／Ｎ比が
低く、感度も少し悪くなるが、ベリファイ可能な記録パ
ワーマージンは広くなる。ある程度のパワー変動に対応
しなければならない実用的記録媒体としてはこの方が適
しているといえる。記録薄膜中Ｏ原子が４５atom％以上
の領域では記録薄膜の熱伝導率が低くなりすぎるため、
記録マークが十分大きく書けず、かなりＣ／Ｎ比が低
く、感度も不十分となってしまい実用に適さない。Table 1 shows each disc No. The evaluation results of 1 to 20 show the maximum value of the C / N ratio and the width of the verifyable recording power margin after 22 ms and several minutes after recording. According to Table 1, O atoms in the recording thin film are 25 atom%
In the following region, the thermal conductivity of the recording thin film is too high, so C
Although the / N ratio is high, the verifyable recording power margin is very narrow or absent, which poses a practical problem. On the other hand, in the region where the number of O atoms in the recording thin film is 25 atom% or more, the thermal conductivity of the recording thin film is low, so that the C / N ratio is relatively low and the sensitivity is a little poor, but the verifyable recording power margin is wide. Become. It can be said that this is more suitable as a practical recording medium that must cope with a certain degree of power fluctuation. Since the thermal conductivity of the recording thin film becomes too low in the region where the number of O atoms in the recording thin film is 45 atom% or more,
The recording mark cannot be written sufficiently large, the C / N ratio is considerably low, and the sensitivity becomes insufficient, which is not suitable for practical use.
【００３０】また記録薄膜中Ｐｄ原子が５atom％以下の
領域では、Ｐｄ不足で記録薄膜の結晶化、すなわち記録
信号の飽和に時間を要し、記録直後のＣ／Ｎ比が低くな
ってしまう。これはＰｄ含有量を増やすことで解消され
るが、逆に増やしすぎると結晶化に伴う反射率変化が光
学的に小さい組成となってしまうため、Ｃ／Ｎ比が低く
なってしまう。その限界は３５atom％程度である。In a region where the Pd atoms in the recording thin film are 5 atom% or less, crystallization of the recording thin film, that is, saturation of the recording signal takes time due to insufficient Pd, and the C / N ratio immediately after recording becomes low. This can be solved by increasing the Pd content, but conversely, if the Pd content is increased too much, the reflectance change due to crystallization will be an optically small composition, resulting in a low C / N ratio. The limit is about 35 atom%.
【００３１】したがって、Ｃ／Ｎ比（記録直後を含
む）、感度、ベリファイなどすべてを考慮に入れると、
線速度にもよるが、記録薄膜中Ｏ原子が２５〜４５atom
％、かつＰｄ原子が５〜３５atom％の組成範囲がこの記
録条件に適しているといえる。この範囲は図１にＡ、
Ｂ、Ｃ、Ｄで囲まれた領域として示してある。Therefore, considering all of the C / N ratio (including immediately after recording), sensitivity, verify, etc.,
Depending on the linear velocity, O atoms in the recording thin film are 25 to 45 atoms.
%, And the composition range of 5 to 35 atom% of Pd atoms is said to be suitable for this recording condition. This range is A in FIG.
It is shown as a region surrounded by B, C, and D.
【００３２】また、全く同じ条件で記録密度のみをビッ
ト長０．７６μｍに変えた場合、すなわちビット長ｂの
スポット径ｄに対する比ｂ／ｄ＝０．８の条件で上記デ
ィスクＮｏ．１〜２０の記録・再生を行った結果を表２
に示す。Further, when only the recording density is changed to 0.76 μm in bit length under exactly the same conditions, that is, the ratio b / d = 0.8 of the bit length b to the spot diameter d, the disc No. Table 2 shows the results of recording and reproducing 1 to 20.
Shown in
【００３３】[0033]
【表２】 [Table 2]
【００３４】表２から明らかな通り、この記録条件に適
する組成範囲は、Ｐｄ含有量の下限こそ５atom％程度で
ｂ／ｄ＝１．０の場合と変わらなかったが、上限は３０
atom％、Ｏ含有量は３０atom％〜４０atom％程度と広く
なった。この範囲は図１にＥ、Ｆ、Ｇ、Ｈで囲まれた領
域として示してある。As is clear from Table 2, the composition range suitable for this recording condition was the same as when b / d = 1.0, with the lower limit of the Pd content being about 5 atom%, but the upper limit was 30.
The atom% and O content were widened to about 30 atom% to 40 atom%. This range is shown in FIG. 1 as a region surrounded by E, F, G, and H.
【００３５】これらの結果より、ビット長ｂのスポット
径ｄに対する比ｂ／ｄが小さくなると、十分な記録特性
の得られる記録薄膜の組成範囲は狭くなることがわか
る。従って、ｂ／ｄ＝１．０の条件では、記録薄膜中Ｏ
原子が２５〜４５atom％、かつＰｄ原子が５〜３５atom
％、ｂ／ｄ＝０．８の条件では、記録薄膜中Ｏ原子が３
０〜４０atom％、かつＰｄ原子が５〜３０atom％の組成
範囲内にあることが必要である。From these results, it is understood that when the ratio b / d of the bit length b to the spot diameter d becomes small, the composition range of the recording thin film where sufficient recording characteristics can be obtained becomes narrow. Therefore, under the condition of b / d = 1.0, O in the recording thin film
25-45 atom% of atoms and 5-35 atom of Pd atoms
%, B / d = 0.8, the number of O atoms in the recording thin film was 3
It is necessary that the composition range is 0 to 40 atom% and Pd atoms is 5 to 30 atom%.
【００３６】ただし、本発明においては記録条件ｂ／ｄ
の下限については特に示さなかったが、本実施の形態の
記録媒体はｂ／ｄ＝０．８〜１．０程度の条件に適した
ものであり、ｂ／ｄがさらに小さい条件、例えばｂ／ｄ
が０．６以下の条件においても良好な記録特性が得られ
るとは限らず、こういった条件に適した記録薄膜のとし
ては、また違った組成範囲のものを検討する必要がある
と考えられる。However, in the present invention, the recording condition b / d
Although the lower limit of is not particularly shown, the recording medium of the present embodiment is suitable for a condition of b / d = 0.8 to 1.0, and a condition that b / d is smaller, for example, b / d. d
Does not always yield good recording characteristics even under conditions of 0.6 or less, and it is considered necessary to study recording thin films suitable for such conditions with different composition ranges. .
【００３７】なお、以上の説明では線速度５．３ｍ／ｓ
の場合の結果のみ示したが、線速度のみを１１．９ｍ／
ｓに変えて、他は全く同じ条件でＮｏ．１〜２０のディ
スクを評価したが、ｂ／ｄ＝１．０及び０．８のいずれ
の条件においてもそれぞれ表１及び表２とほとんど変わ
らない結果が得られた。これにより、上記組成範囲の記
録媒体は１０ｍ／ｓ以上の高線速度においても良好な記
録特性が得られることがわかった。In the above description, the linear velocity is 5.3 m / s.
Although only the result in the case of is shown, only the linear velocity is 11.9 m /
No. under the same conditions other than the above. Disks 1 to 20 were evaluated. Under the conditions of b / d = 1.0 and 0.8, almost the same results as in Table 1 and Table 2 were obtained. From this, it was found that the recording medium having the above composition range had good recording characteristics even at a high linear velocity of 10 m / s or more.
【００３８】また、以上の説明では記録薄膜としてＴ
ｅ、Ｏ、Ｐｄの３元素のみからなる材料を用いた例で説
明したが、熱伝導率、光学定数等の各特性の微調整、あ
るいは耐熱性、環境信頼性の向上等の目的で必要に応じ
てＡｕ、Ｐｔ、Ａｇ、Ｃｕ、Ｂｉ、Ｓｉ、Ｓｅ、Ｓ、
Ｎ、Ｆ、Ｃ等の金属・半金属・半導体及び非金属元素か
ら選ばれる少なくとも１つの元素を副成分として記録薄
膜全体の５atom％以内の組成割合の範囲で添加すること
ができる。Further, in the above description, T is used as the recording thin film.
Although an example using a material consisting of only three elements of e, O, and Pd has been described, it is necessary for the purpose of fine adjustment of each characteristic such as thermal conductivity and optical constant, or improvement of heat resistance and environmental reliability. Accordingly, Au, Pt, Ag, Cu, Bi, Si, Se, S,
At least one element selected from metals, semimetals, semiconductors and non-metal elements such as N, F and C can be added as a sub-component within a composition ratio within 5 atom% of the entire recording thin film.
【００３９】[0039]
【発明の効果】以上説明したとおり、本発明によれば、
透明基板上に少なくとも光ビームの照射により光学的特
性の異なる状態への変化を呈する材料からなる記録薄膜
を有し、前記記録薄膜としてＴｅ、Ｏ及びＰｄを主成分
とし、前記記録薄膜中に含有される前記Ｏ原子の割合が
２５〜４５atom％、かつ前記Ｐｄ原子の割合が５〜３５
atom％の組成割合の範囲内にある材料を用いる。これに
より記録ビット長ｂのスポット径ｄに対する比ｂ／ｄの
小さい情報の記録・再生においてＣ／Ｎ比が高く、ビッ
トエラーの少ない良好な記録特性が広いパワーマージン
で得られる光学的情報記録媒体を提供することができ
る。As described above, according to the present invention,
At least a recording thin film made of a material exhibiting changes in optical characteristics upon irradiation with a light beam on a transparent substrate, wherein the recording thin film contains Te, O and Pd as main components and is contained in the recording thin film. The ratio of the O atom is 25 to 45 atom%, and the ratio of the Pd atom is 5 to 35 atom%.
A material within the composition ratio of atom% is used. As a result, in recording / reproducing information having a small ratio b / d of the recording bit length b to the spot diameter d, an optical information recording medium having a high C / N ratio and good recording characteristics with few bit errors and a wide power margin can be obtained. Can be provided.
【図１】 本発明の一実施の形態の記録薄膜組成範囲図FIG. 1 is a recording thin film composition range diagram according to an embodiment of the present invention.
【図２】 本発明の一実施の形態のディスクの構成断面
図FIG. 2 is a sectional view showing the configuration of a disc according to an embodiment of the present invention.
【図３】 本発明の一実施の形態のディスクの構成断面
図FIG. 3 is a sectional view showing the configuration of a disc according to an embodiment of the present invention.
【図４】 本発明の一実施の形態のディスクの構成断面
図FIG. 4 is a sectional view showing the configuration of a disc according to an embodiment of the present invention.
【図５】 本発明の一実施の形態のディスクの構成断面
図FIG. 5 is a sectional view showing the configuration of a disc according to an embodiment of the present invention.
【図６】 本発明の一実施の形態の記録・再生を行う装
置図FIG. 6 is an apparatus diagram for recording / reproducing according to an embodiment of the present invention.
１ 透明基板 ２ 記録薄膜 ３ オーバーコート層 ４ 接着層 ５ 誘電体層 ６ 反射層 ７ 対物レンズ ８ モーター ９ 半導体レーザー １０ コリメートレンズ １１ レーザービーム １２ ビームスプリッター １３ λ／４波長板 １４ ターンテーブル １５ 検出器 １６ ボイスコイル １７ 光ディスク １８ 入力信号 １９ 再生出力 1 Transparent Substrate 2 Recording Thin Film 3 Overcoat Layer 4 Adhesive Layer 5 Dielectric Layer 6 Reflective Layer 7 Objective Lens 8 Motor 9 Semiconductor Laser 10 Collimating Lens 11 Laser Beam 12 Beam Splitter 13 λ / 4 Wave Plate 14 Turntable 15 Detector 16 Voice coil 17 Optical disc 18 Input signal 19 Playback output
Claims (7)
射により光学的特性の異なる状態への変化を呈する材料
からなる記録薄膜を有する光学的情報記録媒体であっ
て、前記記録薄膜がＴｅ、Ｏ及びＰｄを主成分とし、前
記記録薄膜中に含有される前記Ｔｅ原子の割合が２０〜
７０atom％、前記Ｏ原子の割合が２５〜４５atom％、か
つ前記Ｐｄ原子の割合が５〜３５atom％の組成割合の範
囲内にあることを特徴とする光学的情報記録媒体。1. An optical information recording medium having a recording thin film on a transparent substrate, the recording thin film being made of a material exhibiting a change in optical characteristics to different states upon irradiation with a light beam, wherein the recording thin film is Te, O. And Pd as a main component, and the ratio of the Te atoms contained in the recording thin film is 20 to 20.
An optical information recording medium, wherein the composition ratio is 70 atom%, the O atom ratio is 25 to 45 atom%, and the Pd atom ratio is 5 to 35 atom%.
が３０〜６５atom％、Ｏ原子の割合が３０〜４０atom
％、かつＰｄ原子の割合が５〜３０atom％の組成割合の
範囲内にある請求項１に記載の光学的情報記録媒体。2. The ratio of Te atoms contained in the recording thin film is 30 to 65 atom%, and the ratio of O atoms is 30 to 40 atom.
%, And the proportion of Pd atoms is within the range of composition ratio of 5 to 30 atom%.
囲にある請求項１に記載の光学的情報記録媒体。3. The optical information recording medium according to claim 1, wherein the thickness of the recording thin film is in the range of 20 to 200 nm.
なくとも一方に誘電体材料からなる保護層を有する請求
項１に記載の光学的情報記録媒体。4. The optical information recording medium according to claim 1, wherein a protective layer made of a dielectric material is provided on at least one of the substrate side and the side opposite to the substrate of the recording thin film.
る請求項１に記載の光学的情報記録媒体。5. The optical information recording medium according to claim 1, further comprising a reflective layer on the side of the recording thin film opposite to the substrate.
射により光学的特性の異なる状態への変化を呈する材料
からなる記録薄膜を有し、前記記録薄膜がＴｅ、Ｏ及び
Ｐｄを主成分とし、前記記録薄膜中に含有される前記Ｏ
原子の割合が２５〜４５atom％、かつ前記Ｐｄ原子の割
合が５〜３５atom％の組成割合の範囲内にある光学的情
報記録媒体に情報信号を記録・再生する方法であって、
前記光ビームが対物レンズを通して前記光学的情報記録
媒体に照射される際に、ビーム強度がガウス分布すると
近似した場合、ビーム強度がスポット中心の１／ｅとな
る直径（すなわちスポット径）をｄ、記録ビット長をｂ
として、前記ビット長ｂの前記スポット径ｄに対する比
ｂ／ｄが１．０以下の条件で記録・再生を行うことを特
徴とする記録・再生方法。6. A recording thin film made of a material exhibiting a change in optical characteristics to a different state upon irradiation of a light beam on a transparent substrate, the recording thin film containing Te, O and Pd as main components, The O contained in the recording thin film
A method for recording / reproducing an information signal to / from an optical information recording medium in which the atomic ratio is 25 to 45 atom% and the Pd atomic ratio is in the range of 5 to 35 atom%.
When the light intensity is approximated to a Gaussian distribution when the light beam is applied to the optical information recording medium through the objective lens, the diameter (that is, the spot diameter) at which the beam intensity is 1 / e of the spot center is d, Recording bit length is b
The recording / reproducing method is characterized in that recording / reproducing is performed under the condition that the ratio b / d of the bit length b to the spot diameter d is 1.0 or less.
合が３０〜４０atom％、かつＰｄ原子の割合が５〜３０
atom％の組成割合の範囲内にあり、ビット長ｂのスポッ
ト径ｄに対する比ｂ／ｄが０．８以下である請求項６に
記載の光学的情報記録媒体。7. The ratio of the O atom contained in the recording thin film is 30 to 40 atom%, and the ratio of Pd atom is 5 to 30.
The optical information recording medium according to claim 6, wherein the composition ratio is in the range of atom% and the ratio b / d of the bit length b to the spot diameter d is 0.8 or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8144656A JPH09326135A (en) | 1996-06-06 | 1996-06-06 | Optical information recording medium and its recording and reproducing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8144656A JPH09326135A (en) | 1996-06-06 | 1996-06-06 | Optical information recording medium and its recording and reproducing method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09326135A true JPH09326135A (en) | 1997-12-16 |
Family
ID=15367173
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8144656A Pending JPH09326135A (en) | 1996-06-06 | 1996-06-06 | Optical information recording medium and its recording and reproducing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09326135A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0860295A4 (en) * | 1996-09-09 | 1998-12-09 | Matsushita Electric Ind Co Ltd | Optical information recording medium, its manufacturing method, optical information recording/reproducing method and optical information recorder/reproducer |
| US6610380B2 (en) | 2000-08-17 | 2003-08-26 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium, manufacturing method, recording and reproduction method, and recording/reproduction device |
| US6768710B2 (en) * | 2000-12-18 | 2004-07-27 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium, method for producing the same, and method and apparatus for recording information thereon |
| US8003188B2 (en) | 2006-04-24 | 2011-08-23 | Panasonic Corporation | Information recording medium and method for production thereof |
-
1996
- 1996-06-06 JP JP8144656A patent/JPH09326135A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0860295A4 (en) * | 1996-09-09 | 1998-12-09 | Matsushita Electric Ind 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 |
| US6610380B2 (en) | 2000-08-17 | 2003-08-26 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium, manufacturing method, recording and reproduction method, and recording/reproduction device |
| US6768710B2 (en) * | 2000-12-18 | 2004-07-27 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium, method for producing the same, and method and apparatus for recording information thereon |
| US8003188B2 (en) | 2006-04-24 | 2011-08-23 | Panasonic Corporation | Information recording medium and method for production thereof |
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