JPH0628724A - Magneto-optical recording medium - Google Patents
Magneto-optical recording mediumInfo
- Publication number
- JPH0628724A JPH0628724A JP4207290A JP20729092A JPH0628724A JP H0628724 A JPH0628724 A JP H0628724A JP 4207290 A JP4207290 A JP 4207290A JP 20729092 A JP20729092 A JP 20729092A JP H0628724 A JPH0628724 A JP H0628724A
- Authority
- JP
- Japan
- Prior art keywords
- magneto
- optical recording
- recording medium
- peripheral side
- layer
- 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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はレーザー光を用いて情報
の記録、再生、消去を行なう光磁気記録媒体に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording medium for recording, reproducing and erasing information by using laser light.
【０００２】[0002]
【従来の技術】光磁気記録方式においては、光磁気記録
装置を簡単にするために光磁気ディスクを一定の回転数
で回転させながら用いる、いわゆるＣＡＶ方式が広く用
いられている。光磁気ディスクに記録を行うには記録を
行う部分を一定温度以上に加熱する必要があるが、ＣＡ
Ｖ方式においてはレーザー照射部におけるディスクの線
速度が内周より外周側の方が速くなり、熱効率が低下す
る。このためディスク全面に渡りレーザー照射部の温度
を均一化するためには、外周になるに従いより強いレー
ザー出力が必要となる。2. Description of the Related Art As a magneto-optical recording method, a so-called CAV method is widely used in which a magneto-optical disk is used while rotating at a constant rotational speed in order to simplify a magneto-optical recording apparatus. In order to record on a magneto-optical disk, it is necessary to heat the part to be recorded above a certain temperature.
In the V method, the linear velocity of the disk in the laser irradiation portion is higher on the outer peripheral side than on the inner peripheral side, and the thermal efficiency is reduced. Therefore, in order to make the temperature of the laser irradiation portion uniform over the entire surface of the disk, a stronger laser output is required toward the outer circumference.
【０００３】しかしながらＣＡＶ方式で光磁気ディスク
を駆動する場合、記録レーザー出力を内周から外周側に
向って段階的に大きくすることは半導体レーザーのパワ
ーマージンを大きくする必要があり、又、出力制御回路
等を複雑にし、ドライブ側にとって負担となっている。However, when the magneto-optical disk is driven by the CAV method, it is necessary to increase the power margin of the semiconductor laser and increase the output control in order to increase the recording laser output stepwise from the inner circumference toward the outer circumference. It complicates the circuit, etc. and is a burden on the drive side.
【０００４】特開昭５７−１５２５５５号公報では、Ｔ
ｂＦｅの組成を内周から外周側に連続的に変化させた光
磁気記録層によりキュリー点を内周から外周側に連続的
に小さくなるようにしている。キュリー点を変えること
で、記録ビットのコントラストの均一化を図っている。
しかしディスクの内外周で記録層の組成を制御すること
は成膜技術的に複雑であり、特にスループット、歩留ま
りの点で優れたスパッタ法では困難である。In Japanese Patent Application Laid-Open No. 57-152555, T
The Curie point is continuously reduced from the inner circumference to the outer circumference by the magneto-optical recording layer in which the composition of bFe is continuously changed from the inner circumference to the outer circumference. By changing the Curie point, the contrast of recorded bits is made uniform.
However, controlling the composition of the recording layer on the inner and outer peripheries of the disk is complicated in terms of film-forming technology, and it is particularly difficult for the sputtering method, which is excellent in terms of throughput and yield.
【０００５】特開昭６１−２１１８５２号公報では、支
持基板、保護層、光磁気記録層、反射層の構成の光磁気
記録媒体において反射層の膜厚を径方向に変化させてい
る。しかし、この構成では反射層が光磁気記録層に密着
しているために熱拡散率が大きく、第２誘電体保護層が
ある場合に比ベて、記録に必要なレーザー出力が大きく
なりパワーマージンの点で好ましくない。又、熱拡散率
の勾配を径方向に設定するのに大きな膜厚の変化を必要
とする。このことはディスクの信頼性を低下させるなど
の一因となる。In Japanese Patent Laid-Open No. 61-211852, in a magneto-optical recording medium having a supporting substrate, a protective layer, a magneto-optical recording layer and a reflecting layer, the thickness of the reflecting layer is changed in the radial direction. However, in this structure, since the reflective layer is in close contact with the magneto-optical recording layer, the thermal diffusivity is large, and the laser output required for recording is large compared with the case where the second dielectric protective layer is provided, and the power margin is increased. Is not preferable. Further, a large change in film thickness is required to set the thermal diffusivity gradient in the radial direction. This is one of the causes of lowering the reliability of the disc.
【０００６】特開平３−６９０３９号公報では、透明な
円板状基板、誘電体、熱拡散膜、保護膜の構成の光磁気
記録媒体において熱拡散膜の膜厚を基板の中心部から外
周部にかけて連続的もしくは段階的に薄くしている。こ
の場合も特開昭６１−２１１８５２号公報と同じ理由で
好ましくない。In Japanese Patent Laid-Open No. 3-69039, in a magneto-optical recording medium having a transparent disk-shaped substrate, a dielectric, a heat diffusion film, and a protective film, the thickness of the heat diffusion film is changed from the central portion to the outer peripheral portion of the substrate. It is continuously or stepwise thinned over time. This case is also not preferable for the same reason as in JP-A-61-211852.
【０００７】[0007]
【発明が解決しようとする課題】本発明の目的は、信頼
性及び感度に優れるとともに内周から外周部にかけての
記録に必要なレーザー出力の変化の少ない光磁気記録媒
体を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a magneto-optical recording medium which is excellent in reliability and sensitivity and has a small change in laser output required for recording from the inner circumference to the outer circumference.
【０００８】[0008]
【課題を解決するための手段】上記本発明の目的は、透
明な円盤基板上に第１誘電体保護層、光磁気記録層、第
２誘電体保護層、Ａｌ合金反射層及び紫外線硬化型樹脂
層がこの順で積層された光磁気記録媒体の各層のうち第
１誘電体保護層、Ａｌ合金反射層、第２誘電体保護層、
光磁気記録層の膜厚を記録媒体の径方向に連続的あるい
は段階的に変化させることで、あるいは更にＡｌ合金反
射層のＡｌ組成を径方向に変化させることで達成され
る。The above object of the present invention is to provide a first dielectric protective layer, a magneto-optical recording layer, a second dielectric protective layer, an Al alloy reflective layer and an ultraviolet curable resin on a transparent disk substrate. A first dielectric protective layer, an Al alloy reflective layer, a second dielectric protective layer among the layers of the magneto-optical recording medium in which the layers are laminated in this order,
This is achieved by continuously or stepwise changing the film thickness of the magneto-optical recording layer in the radial direction of the recording medium, or by further changing the Al composition of the Al alloy reflective layer in the radial direction.
【０００９】即ち、Ａｌ合金反射層のＡｌ組成が径方向
に変化し、Ａｌ組成の割合が径の外周ほど低くなり、か
つ第１誘電体保護層の膜厚が記録媒体の径方向に変化
し、その際外周側における膜厚が内周側よりも薄いこと
を特微とする光磁気記録媒体である。That is, the Al composition of the Al alloy reflective layer changes in the radial direction, the proportion of the Al composition decreases toward the outer periphery of the diameter, and the film thickness of the first dielectric protective layer changes in the radial direction of the recording medium. In this case, the magneto-optical recording medium is characterized in that the film thickness on the outer peripheral side is thinner than that on the inner peripheral side.
【００１０】又、第１誘電体保護層の膜厚が記録媒体の
径方向に変化し、その際外周側における膜厚が内周側よ
りも薄く、かつＡｌ合金反射層の膜厚が記録媒体の径方
向に変化し、その際外周側における膜厚が内周側よりも
薄い光磁気記録媒体である。Further, the film thickness of the first dielectric protective layer changes in the radial direction of the recording medium, in which case the film thickness on the outer peripheral side is thinner than that on the inner peripheral side and the film thickness of the Al alloy reflective layer is the recording medium. Of the magneto-optical recording medium in which the film thickness on the outer peripheral side is thinner than that on the inner peripheral side.
【００１１】更に又、第１誘電体保護層の膜厚が記録媒
体の径方向に変化し、その際外周側における膜厚が内周
側よりも薄く、かつ第２誘電体保護層の膜厚が記録媒体
の径方向に変化し、その際外周側における膜厚が内周側
よりも厚い光磁気記録媒体である。Furthermore, the film thickness of the first dielectric protective layer changes in the radial direction of the recording medium, the film thickness on the outer peripheral side is smaller than that on the inner peripheral side, and the film thickness of the second dielectric protective layer. Changes in the radial direction of the recording medium, and at that time, the film thickness on the outer peripheral side is thicker than that on the inner peripheral side.
【００１２】又、第１誘電体保護層の膜厚が記録媒体の
径方向に変化し、その際外周側における膜厚が内周側よ
りも薄く、かつ光磁気記録層の膜厚が記録媒体の径方向
に変化し、その際外周側における膜厚が内周側よりも薄
い光磁気記録媒体である。Further, the film thickness of the first dielectric protective layer changes in the radial direction of the recording medium, the film thickness on the outer peripheral side is smaller than that on the inner peripheral side, and the film thickness of the magneto-optical recording layer is smaller than that of the recording medium. Of the magneto-optical recording medium in which the film thickness on the outer peripheral side is thinner than that on the inner peripheral side.
【００１３】以下、図面に基づいて本発明を説明する。
比較の便宜上、従来の光磁気記録媒体から述べる。The present invention will be described below with reference to the drawings.
For convenience of comparison, the conventional magneto-optical recording medium will be described first.
【００１４】図１は従来の光磁気記録媒体を示し、透明
な円盤基板１の上に第１誘電体保護層２、光磁気記録層
３、第２誘電体保護層４、Ａｌ合金反射層５及び紫外線
硬化型樹脂層６がこの順で積層されている。光磁気ディ
スクが１８００回転／分で回転しているとき、半径２４
ｍｍでの線速度は４.５ｍ／ｓ、半径３９.５ｍｍでの線
速度は７.４ｍ／ｓと異なるため、同一のレーザー出力
で記録媒体を加熱すると、外周になるほど単位面積当り
の受け取るエネルギーは小さくなり、ディスク全面にお
いて照射部を均一の温度に加熱するには外周側程レーザ
ー出力を強くする必要がある。つまりＣＡＶ方式では、
内周より外周側の方が記録に要するレーザー出力は高く
する必要がある。記録レーザーの出力が適正の時、適正
な記録ビットが光磁気記録層に形成されるが、適正以上
のレーザー出力をかけた場合は記録ビットが大きくなり
すぎＣＮＲ（Carrier to Noise Ratio）が低下する。ま
た適正以下のレーザー出力の場合もＣＮＲは低下する。FIG. 1 shows a conventional magneto-optical recording medium, in which a first dielectric protective layer 2, a magneto-optical recording layer 3, a second dielectric protective layer 4 and an Al alloy reflective layer 5 are provided on a transparent disk substrate 1. And the ultraviolet curable resin layer 6 are laminated in this order. When the magneto-optical disk is rotating at 1800 rpm, the radius is 24
Since the linear velocity in mm is 4.5 m / s and the linear velocity in a radius of 39.5 mm is 7.4 m / s, when the recording medium is heated with the same laser output, the energy received per unit area becomes closer to the outer circumference. Becomes smaller, and it is necessary to increase the laser output toward the outer peripheral side in order to heat the irradiation part to a uniform temperature over the entire surface of the disk. That is, in the CAV method,
It is necessary to increase the laser output required for recording on the outer circumference side than the inner circumference side. When the output of the recording laser is appropriate, an appropriate recording bit is formed in the magneto-optical recording layer, but when the laser output above the appropriate level is applied, the recording bit becomes too large and the CNR (Carrier to Noise Ratio) decreases. . The CNR is also reduced when the laser output is below the proper level.
【００１５】図１の従来の場合、直径８６ｍｍのポリカ
ーボネート基板１上に第１誘電体保護層２としてシリコ
ン窒化膜を９００Å、光磁気記録層３としてＤｙ１５Ｔ
ｂ７Ｆｅ７０Ｃｏ８を２００Å第２誘電体保護層４とし
てシリコン窒化膜を３００Å、Ａｌ合金反射膜５として
アルミニウム・チタン合金を５００Å、紫外線硬化型樹
脂１μｍを積層した場合の光磁気ディスクのＣＮＲの記
録レーザー出力依存性を図６に示す。半径２４.１ｍｍ
と半径３９.５ｍｍでのＣＮＲの不均一性が顕著にみら
れる。In the conventional case of FIG. 1, a silicon nitride film as a first dielectric protection layer 2 is 900Å and a magneto-optical recording layer 3 is Dy15T on a polycarbonate substrate 1 having a diameter of 86 mm.
b7Fe70Co8 is 200 Å The second dielectric protection layer 4 is a silicon nitride film 300 Å, the Al alloy reflection film 5 is an aluminum / titanium alloy 500 Å, and the UV curable resin 1 μm is laminated. The sex is shown in FIG. Radius 24.1mm
And the non-uniformity of CNR at a radius of 39.5 mm is noticeable.
【００１６】図２は本発明の光磁気記録媒体の実施例を
示すもので、第１誘電体保護層２ａは屈折率２.１５の
シリコン窒化膜を半径２４ｍｍで１０００Å、半径３
９.５ｍｍで９００Åになるように成膜したものであ
る。又、Ａｌ合金反射層５ａのＡｌ組成は最内周に当た
るところで９５％、最外周に当たるところで９０％にな
るようにＡｌ組成を連続的あるいは段階的に変化させて
いる。Ａｌに添加する元素としてはＴｉを用いている。
他の各層の条件は図１の場合と同じである。FIG. 2 shows an embodiment of the magneto-optical recording medium of the present invention. The first dielectric protective layer 2a is a silicon nitride film having a refractive index of 2.15, a radius of 24 mm, a length of 1000 Å, and a radius of 3.
The film was formed to have a thickness of 900 Å at 9.5 mm. Further, the Al composition of the Al alloy reflection layer 5a is changed continuously or stepwise so that the Al composition reaches 95% at the innermost circumference and 90% at the outermost circumference. Ti is used as an element added to Al.
The conditions for the other layers are the same as in FIG.
【００１７】第１誘電体保護層はレーザーによって加熱
された光磁気記録層３の熱が拡散する場合の熱溜の働き
をし、第１誘電体保護層の膜厚が厚くなるほど光磁気記
録層から熱が奪われ易くなる。このため内周側に比ベ外
周側でのレーザー照射による熱効率が改善される。ま
た、Ｔｉ組成の割合の高いＡｌ合金ほど熱伝導率が低く
なるため、外周側ほど熱が逃げにくく、熱効率が改善さ
れる。The first dielectric protective layer acts as a heat reservoir when the heat of the magneto-optical recording layer 3 heated by the laser diffuses, and the thicker the first dielectric protective layer is, the magneto-optical recording layer. It becomes easy to take away heat from. For this reason, the thermal efficiency of the laser irradiation on the outer peripheral side relative to the inner peripheral side is improved. Further, since the Al alloy having a higher proportion of Ti has a lower thermal conductivity, the heat is less likely to escape toward the outer peripheral side, and the thermal efficiency is improved.
【００１８】この構成での光磁気ディスクのＣＮＲの記
録レーザー出力依存性を図７に示す。内周（半径２４.
２ｍｍ）と外周（３９.５ｍｍ）でのＣＮＲの均一性が
改善されている。従ってディスクの内周と外周でレーザ
ー出力を変える必要がない。FIG. 7 shows the dependence of the CNR of the magneto-optical disk having this structure on the recording laser output. Inner circumference (radius 24.
2 mm) and the outer circumference (39.5 mm) have improved CNR uniformity. Therefore, it is not necessary to change the laser output between the inner circumference and the outer circumference of the disk.
【００１９】図３は本発明の光磁気記録媒体の別の実施
例を示す図で、第１誘電体保護層２ａは屈折率２.１５
のシリコン窒化膜を半径２４ｍｍで１０００Å、半径３
９.５ｍｍで９００Åになるように、さらに光磁気記録
層３ａはＴｂＤｙＦｅＣｏ合金を半径２４ｍｍで２００
Å、半径３９.５ｍｍで１５０Åになるように成膜した
ものである。他の各層の条件は図１の場合と同じであ
る。レーザーよって加熱された光磁気記録層３ａの熱は
第２誘電体保護層４を介してＡｌ反射層５に拡散放出さ
れ、又、光磁気記録層３ａの熱は第１誘電体保護層２ａ
に拡散される。光磁気記録層３ａの熱容量は膜厚が厚い
場所ほど大きくなる。又、外周側の第１誘電体保護層の
膜厚が薄いので内周側よりも外周側でのレーザー照射に
よる熱効率が改善される。FIG. 3 is a diagram showing another embodiment of the magneto-optical recording medium of the present invention, in which the first dielectric protective layer 2a has a refractive index of 2.15.
The silicon nitride film of 1000 Å with a radius of 24 mm and a radius of 3
Further, the magneto-optical recording layer 3a is made of a TbDyFeCo alloy having a radius of 24 mm and a thickness of 200 mm so as to be 900 Å at 9.5 mm.
Å, a film having a radius of 39.5 mm and a thickness of 150 Å. The conditions for the other layers are the same as in FIG. The heat of the magneto-optical recording layer 3a heated by the laser is diffused and emitted to the Al reflection layer 5 through the second dielectric protection layer 4, and the heat of the magneto-optical recording layer 3a is also discharged to the first dielectric protection layer 2a.
Be spread to. The heat capacity of the magneto-optical recording layer 3a increases as the film thickness increases. Moreover, since the film thickness of the first dielectric protective layer on the outer peripheral side is thin, the thermal efficiency by laser irradiation on the outer peripheral side is improved rather than on the inner peripheral side.
【００２０】図４は本発明の光磁気記録媒体の更に別の
実施例を示すもので、第１誘電体保護層２ａは屈折率
２.１５のシリコン窒化膜を半径２４ｍｍで１０００
Å、半径３９.５ｍｍで９００Åになるように、更に第
２誘電体保護体４ａは屈折率２.１５のシリコン窒化膜
を半径２４ｍｍで２５０Å、半径３９.５ｍｍで３００
Åになるように成膜したものである。他の各層の条件は
図１の場合と同じである。第２誘電体保護層はレーザー
よって加熱された光磁気記録層３の熱がＡｌ合金反射層
５まで拡散する場合の熱抵抗として働くため、第２誘電
体保護層の膜厚が厚くなるほど光磁気記録層から熱が逃
げにくくなる。また外周側の第１誘電体保護層の膜厚が
薄いので内周側よりも外周側でのレーザー照射による熱
効率が改善される。FIG. 4 shows another embodiment of the magneto-optical recording medium of the present invention. The first dielectric protective layer 2a is a silicon nitride film having a refractive index of 2.15 and a radius of 24 mm of 1000.
Å, the second dielectric protector 4a is a silicon nitride film having a refractive index of 2.15 of 250 Å with a radius of 24 mm and 300 Å with a radius of 39.5 mm.
The film was formed so as to become Å. The conditions for the other layers are the same as in FIG. Since the second dielectric protection layer acts as a thermal resistance when the heat of the magneto-optical recording layer 3 heated by the laser diffuses to the Al alloy reflection layer 5, the thicker the second dielectric protection layer is, the more the magneto-optical property is increased. It becomes difficult for heat to escape from the recording layer. Further, since the thickness of the first dielectric protective layer on the outer peripheral side is thin, the thermal efficiency due to laser irradiation on the outer peripheral side is improved rather than on the inner peripheral side.
【００２１】図５は本発明の光磁気記録媒体の更にまた
別の実施例を示すもので、第１誘電体保護層２ａは屈折
率２.１５のシリコン窒化膜を半径２４ｍｍで１０００
Å、半径３９.５ｍｍで９００Åになるように、更に金
属反射層５ｂはアルミニウム・チタン合金を半径２４ｍ
ｍで６００Å、半径３９.５ｍｍで５００Åになるよう
に成膜したものである。他の各層の条件は図１の場合と
同じである。レーザーによって加熱された光磁気記録層
３の熱は第２誘電体保護層４を介してＡｌ合金反射層５
ｂに拡散放出される。Ａｌ合金反射層は熱の良導体であ
り、薄膜の膜厚が厚い場所ほど熱容量が大きくなり光磁
気記録層の熱を逃し安くなる。又、外周側の第１誘電体
保護層の膜厚が薄いので内周側よりも外周側でのレーザ
ー照射による熱効率が改善される。FIG. 5 shows still another embodiment of the magneto-optical recording medium of the present invention. The first dielectric protective layer 2a is a silicon nitride film having a refractive index of 2.15 and a radius of 24 mm of 1000.
Å, the metal reflective layer 5b is made of aluminum / titanium alloy with a radius of 24 m so that the radius becomes 39.5 mm and 900Å.
The film was formed so as to have a thickness of 600Å in m and a radius of 39.5 mm in 500Å. The conditions for the other layers are the same as in FIG. The heat of the magneto-optical recording layer 3 heated by the laser is transmitted through the second dielectric protection layer 4 to the Al alloy reflection layer 5
It is diffused and emitted to b. The Al alloy reflection layer is a good conductor of heat, and the larger the thickness of the thin film, the larger the heat capacity, and the more the heat of the magneto-optical recording layer escapes, the cheaper it becomes. Moreover, since the film thickness of the first dielectric protective layer on the outer peripheral side is thin, the thermal efficiency by laser irradiation on the outer peripheral side is improved rather than on the inner peripheral side.
【００２２】[0022]
【発明の効果】以上の如く本発明による各構成の光磁気
記録媒体はいずれも内周に対して外周側のレーザー照射
による熱効率が改善されるので、各々レーザー出力に対
してディスク全面にわたり均一なＣＮＲが得られる。こ
のため半導体レーザーの出力制御回路等を簡略化でき
る。As described above, in each of the magneto-optical recording media according to the present invention, the thermal efficiency of the laser irradiation on the outer circumference side with respect to the inner circumference is improved, so that the laser output is uniform over the entire disk surface. CNR is obtained. Therefore, the output control circuit of the semiconductor laser can be simplified.
【図１】従来の光磁気記録媒体の断面を示す模式図。FIG. 1 is a schematic view showing a cross section of a conventional magneto-optical recording medium.
【図２】[Fig. 2]
【図３】[Figure 3]
【図４】[Figure 4]
【図５】以上、本発明の光磁気記録媒体の断面を示す模
式図。FIG. 5 is a schematic view showing a cross section of the magneto-optical recording medium of the present invention.
【図６】[Figure 6]
【図７】以上、光磁気記録媒体のＣＮＲの記録レーザー
出力依存性を示す図で、図６は従来の、又、図７は本発
明の光磁気記録媒体のそれを示す。7 is a diagram showing the recording laser output dependence of CNR of a magneto-optical recording medium, FIG. 6 showing that of a conventional magneto-optical recording medium, and FIG. 7 showing that of a magneto-optical recording medium of the present invention.
１ 透明基板 ２、２ａ 第１誘電体保護層 ３、３ａ 光磁気記録層 ４、４ａ 第２誘電体保護層 ５、５ａ、５ｂ Ａｌ合金反射膜 ６ 紫外線硬化型樹脂層 1 transparent substrate 2, 2a first dielectric protective layer 3, 3a magneto-optical recording layer 4, 4a second dielectric protective layer 5, 5a, 5b Al alloy reflective film 6 ultraviolet curable resin layer
Claims (8)
光磁気記録層、第２誘電体保護層、Ａｌ合金反射層及び
紫外線硬化樹脂がこの順で積層された光磁気記録媒体に
おいて、第１誘電体保護層の膜厚が記録媒体の径方向に
変化し、かつＡｌ合金反射層の合金組成が記録媒体の径
方向に変化し、その際外周側におけるＡｌの組成の割合
が内周側よりも低いことを特徴とする光磁気記録媒体。1. A first dielectric protective layer on a transparent disk substrate,
In a magneto-optical recording medium in which a magneto-optical recording layer, a second dielectric protective layer, an Al alloy reflective layer and an ultraviolet curable resin are laminated in this order, the film thickness of the first dielectric protective layer changes in the radial direction of the recording medium. In addition, the magneto-optical recording medium is characterized in that the alloy composition of the Al alloy reflective layer changes in the radial direction of the recording medium, and the proportion of Al composition on the outer peripheral side is lower than that on the inner peripheral side.
２.３０のシリコン窒化膜とし、基板のグループの最外
周部から最内周部に位置する第１誘電体保護層の膜厚を
８００〜１０００Åの範囲とすることを特徴とする請求
項１記載の光磁気記録媒体。2. The first dielectric protective layer has a refractive index of 2.00 to
2. The silicon nitride film of 2.30, wherein the film thickness of the first dielectric protective layer located from the outermost peripheral portion to the innermost peripheral portion of the group of substrates is in the range of 800 to 1000Å. Magneto-optical recording medium.
が内周側よりも薄く、かつ光磁気記録層の膜厚が記録媒
体の径方向に変化し、その際外周側における膜厚が内周
側よりも薄いことを特徴とする請求項２記載の光磁気記
録媒体。3. The film thickness on the outer peripheral side of the first dielectric protective layer is thinner than that on the inner peripheral side, and the film thickness of the magneto-optical recording layer changes in the radial direction of the recording medium. 3. The magneto-optical recording medium according to claim 2, wherein is thinner than the inner peripheral side.
し、基板のグループの最外周側から最内周部に位置する
光磁気記録層の膜厚を１５０〜３００Åの範囲にするこ
とを特徴とする請求項３記載の光磁気記録媒体。4. The magneto-optical recording layer is made of a TbDyFeCo alloy, and the film thickness of the magneto-optical recording layer located from the outermost peripheral side to the innermost peripheral portion of the substrate group is set in the range of 150 to 300Å. Item 3. A magneto-optical recording medium.
が内周側よりも薄く、かつ第２誘電体保護層の膜厚が記
録媒体の径方向に変化し、その際外周側における膜厚が
内周側よりも厚いことを特徴とする請求項２記載の光磁
気記録媒体。5. The film thickness on the outer peripheral side of the first dielectric protective layer is thinner than that on the inner peripheral side, and the film thickness of the second dielectric protective layer changes in the radial direction of the recording medium. The magneto-optical recording medium according to claim 2, wherein the film thickness is thicker than the inner peripheral side.
２.３０のシリコン窒化膜とし、基板のグループの最外
周部から最内周部に位置する第２誘電体保護層の膜厚を
２５０〜３５０Åの範囲とすることを特徴とする請求項
５記載の光磁気記録媒体。6. The second dielectric protective layer has a refractive index of 2.00 to
6. The silicon nitride film of 2.30, wherein the film thickness of the second dielectric protection layer located from the outermost peripheral portion to the innermost peripheral portion of the substrate group is in the range of 250 to 350Å. Magneto-optical recording medium.
が内周側よりも薄く、かつＡｌ合金反射層の膜厚が記録
媒体の径方向に変化し、その際外周側における膜厚が内
周側よりも薄いことを特徴とする請求項２記載の光磁気
記録媒体。7. The film thickness on the outer peripheral side of the first dielectric protective layer is thinner than that on the inner peripheral side, and the film thickness of the Al alloy reflective layer changes in the radial direction of the recording medium, in which case the film thickness on the outer peripheral side. 3. The magneto-optical recording medium according to claim 2, wherein is thinner than the inner peripheral side.
に位置するＡｌ合金反射層の膜厚を４００〜６５０Åの
範囲とすることを特徴とする請求項７記載の光磁気記録
媒体。8. The magneto-optical recording medium according to claim 7, wherein the film thickness of the Al alloy reflective layer located from the outermost peripheral portion to the innermost peripheral portion of the groove of the substrate is in the range of 400 to 650Å.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4207290A JPH0628724A (en) | 1992-07-10 | 1992-07-10 | Magneto-optical recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4207290A JPH0628724A (en) | 1992-07-10 | 1992-07-10 | Magneto-optical recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0628724A true JPH0628724A (en) | 1994-02-04 |
Family
ID=16537350
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4207290A Pending JPH0628724A (en) | 1992-07-10 | 1992-07-10 | Magneto-optical recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0628724A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0751511A2 (en) * | 1995-06-30 | 1997-01-02 | Sony Corporation | Magneto-optical disc |
| JP2007334141A (en) * | 2006-06-16 | 2007-12-27 | Sanyo Electric Co Ltd | Culture observation system |
-
1992
- 1992-07-10 JP JP4207290A patent/JPH0628724A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0751511A2 (en) * | 1995-06-30 | 1997-01-02 | Sony Corporation | Magneto-optical disc |
| EP0751511A3 (en) * | 1995-06-30 | 1997-06-25 | Sony Corp | Magneto-optical disc |
| US5751670A (en) * | 1995-06-30 | 1998-05-12 | Sony Corporation | Magneto-optical disk having variable thickness recording layer but adequate uniform reflectance value |
| JP2007334141A (en) * | 2006-06-16 | 2007-12-27 | Sanyo Electric Co Ltd | Culture observation system |
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