JPH07282468A - Optical disk substrate and optical disk - Google Patents
Optical disk substrate and optical diskInfo
- Publication number
- JPH07282468A JPH07282468A JP6067160A JP6716094A JPH07282468A JP H07282468 A JPH07282468 A JP H07282468A JP 6067160 A JP6067160 A JP 6067160A JP 6716094 A JP6716094 A JP 6716094A JP H07282468 A JPH07282468 A JP H07282468A
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- recording
- groove
- layer
- height
- 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
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/263—Moulds with mould wall parts provided with fine grooves or impressions, e.g. for record discs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/263—Moulds with mould wall parts provided with fine grooves or impressions, e.g. for record discs
- B29C2045/2667—Particular inner or outer peripheral portions of the substrate
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は記録媒体として有用な、
光ディスク基板および光ディスクに関するものである。The present invention is useful as a recording medium,
The present invention relates to an optical disk substrate and an optical disk.
【０００２】[0002]
【従来の技術】光ヘッドを用いて、情報を記録または再
生する光ディスクは、記録密度が高いため音楽やコンピ
ューターの記憶素子として広く応用されている。通常、
光ディスクの記録層は、スパッタリング、真空蒸着等の
真空成膜法で形成されている。その上には記録層を保護
するため紫外線硬化型アクリル樹脂による保護コート層
が形成されるが、基板の外周端部（角部）と内周端部は
共に保護コート層の膜厚が薄くなるため保護効果が弱
く、酸化や腐食によって記録層が欠損することがある。
そのため記録層を成膜する際にはディスクの内外周部に
マスクを装着し、端部まで記録層が形成されないように
している（図４参照）。しかし、全表面が平坦な基板に
マスクを装着した場合には、マスク表面と基板表面の間
に段差が発生し、そのためマスクの基板側端部から 1.5
mm程度は記録層の膜厚が薄くなる傾向がある。この膜厚
の減少により光の反射率が変化したり、ディスクの最内
周部および最外周部までは情報を記録または再生するこ
とができなくなるという問題があった。2. Description of the Related Art Optical discs for recording or reproducing information by using an optical head are widely applied as music or storage elements for computers because of their high recording density. Normal,
The recording layer of the optical disk is formed by a vacuum film forming method such as sputtering or vacuum evaporation. A protective coating layer made of UV-curable acrylic resin is formed on top of this to protect the recording layer, but the thickness of the protective coating layer becomes thin at both the outer peripheral edge (corner) and the inner peripheral edge of the substrate. Therefore, the protective effect is weak, and the recording layer may be damaged by oxidation or corrosion.
Therefore, when forming the recording layer, a mask is attached to the inner and outer peripheral portions of the disc so that the recording layer is not formed up to the end portion (see FIG. 4). However, when the mask is mounted on a substrate whose entire surface is flat, a step is generated between the mask surface and the substrate surface, which causes 1.5 mm from the edge of the mask on the substrate side.
The thickness of about mm tends to reduce the thickness of the recording layer. Due to this decrease in film thickness, there have been problems that the reflectance of light changes and information cannot be recorded or reproduced up to the innermost peripheral portion and the outermost peripheral portion of the disc.
【０００３】内周から外周部まで記録領域全体で記録膜
の厚さを一定にする方法として、特開平２−282942号で
はディスク基板の外周部に段差を形成し、段差を利用し
てマスクと基板面の高さの差を小さくすることが開示さ
れており、この方法によればマスクにより記録層の膜厚
が薄くなる現象は軽減することができる。また、ディス
ク基板の外周部に段差や溝または面取り部分を形成する
ことは、貼り合わせ基板において接着剤のはみ出しを
防止する、保護コート層が記録層を十分に保護でき
る、ヘッドクラッシュを防止できる等の理由で数多く
開示されている（特開平２−282941号、特開平３−1768
31号、実開平３−76222 号、実開平３−76223 号、特開
平５−47035 号参照）。As a method of making the thickness of the recording film constant in the entire recording area from the inner circumference to the outer circumference, Japanese Patent Laid-Open No. 282942/1990 discloses forming a step on the outer circumference of a disk substrate and using the step as a mask. It is disclosed that the height difference of the substrate surface is reduced, and according to this method, the phenomenon that the thickness of the recording layer is thinned by the mask can be reduced. Further, forming a step, a groove, or a chamfered portion on the outer peripheral portion of the disk substrate prevents the adhesive from squeezing out in the bonded substrate, the protective coating layer can sufficiently protect the recording layer, and the head crash can be prevented. For this reason, many have been disclosed (JP-A-2-282941 and JP-A-3-1768).
31, JP-A-3-76222, JP-A-3-76223, and JP-A-5-47035).
【０００４】しかしながら、本発明者等は高出力のスパ
ッタリング装置で記録層を成膜することを検討した。そ
の結果、特に高出力、例えば 150mmφのターゲットに４
kw以上を印加した時、基板の単位面積あたり25w/cm2 以
上の出力でスパッタ成膜を行った時に、マスクの端部
（鋭角頂部）と基板上の形成された膜の端部との距離が
ある程度（約 0.1mm）以下になると、マスクの付近で異
常放電が発生し外周部での記録層の膜厚が薄くなった
り、プラスチック製の基板の表面が昇温により溶融する
ことがわかった。このような異常放電を防止するために
は、例えば特開平３−168948号に開示されているように
マスクを基板の表面から離すことが有効である。しか
し、前述したようにマスクを基板から離し過ぎると外周
部で記録層の膜厚が薄くなるという不利がある。例え
ば、呼称直径90mmφの光磁気ディスクの場合、現行の規
格（日本規格協会：JIS X 6272-'92）では、最外周が半
径41mm（82mmφ）まで使用されることになっており、基
板の径が86mmφであることを考えれば、基板の最外周か
ら２mmの間で、記録層がマスクされる必要がある。も
し、１mmの幅をマスクすると、情報を記録する最外周ま
での間隔は、残りが１mmとなり、この間で記録層の膜厚
を均一にするのは困難である。また、記録容量を増やす
ために、さらに外周まで記録領域を形成した場合には、
マスクと記録領域との間隔がさらに縮められるので最外
周まで記録層を一定の膜厚で形成することはできないと
いう不利が生ずる。However, the inventors of the present invention considered forming the recording layer with a high-power sputtering apparatus. As a result, especially for high output, for example, a target of 150 mmφ, 4
The distance between the edge of the mask (the apex) and the edge of the film formed on the substrate when sputter deposition is performed with an output of 25 w / cm 2 or more per unit area of the substrate when applying kw or more. It has been found that when the temperature is below a certain level (about 0.1 mm), an abnormal discharge occurs near the mask, the thickness of the recording layer at the outer periphery becomes thin, and the surface of the plastic substrate melts due to temperature rise. . In order to prevent such abnormal discharge, it is effective to separate the mask from the surface of the substrate as disclosed in, for example, JP-A-3-168948. However, as described above, if the mask is too far from the substrate, there is a disadvantage that the film thickness of the recording layer becomes thin in the outer peripheral portion. For example, in the case of a magneto-optical disk with a nominal diameter of 90 mmφ, the current standard (Japanese Standards Association: JIS X 6272-'92) requires that the outermost circumference be used up to a radius of 41 mm (82 mmφ). Is 86 mmφ, the recording layer needs to be masked within 2 mm from the outermost periphery of the substrate. If the width of 1 mm is masked, the distance to the outermost circumference for recording information remains 1 mm, and it is difficult to make the thickness of the recording layer uniform during this interval. In addition, in order to increase the recording capacity, if the recording area is further formed up to the outer circumference,
Since the distance between the mask and the recording area is further reduced, there is a disadvantage that the recording layer cannot be formed with a constant film thickness up to the outermost circumference.
【０００５】[0005]
【発明が解決しようとする課題】本発明の目的は、基板
上に情報を記録または再生するための記録層を有する光
ディスク基板において、外周端部付近まで安定して情報
を記録できる領域を確保でき、また、高出力で記録層を
成膜しても異常放電が発生せず高速で成膜できる光ディ
スク基板および光ディスクを提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide an optical disk substrate having a recording layer for recording or reproducing information on the substrate, and to secure a region in which information can be stably recorded up to the outer peripheral edge. Another object of the present invention is to provide an optical disk substrate and an optical disk that can be formed at high speed without abnormal discharge even if a recording layer is formed with high output.
【０００６】[0006]
【課題を解決するための手段】本発明者等は、かかる課
題を解決するために、基板の端部形状について種々検討
と試行を重ね、諸条件を確立して本発明を完成したもの
で、その要旨は、光を用いて情報を記録または再生する
光ディスクの基板において、基板の外周部の少なくとも
一面に凹状の溝を形成し、該溝の記録領域とは反対側の
基板の高さを、記録領域側の基板の高さより低くして成
り、基板の高さをａ、溝の記録領域とは反対側の基板の
高さをｃ、その差ｄ＝ａ−ｃとした時、式ａ＞ｃまたは
0.1≦ｄ≦1.0 (mm)を満足し、凹状の溝の縦断面形状が
矩形、楔形または矩形の角を落としてＲをつけた形であ
る光ディスク基板、および該光ディスク基板の表面に情
報を記録または再生するための記録層を形成して成る光
ディスクにある。In order to solve such a problem, the inventors of the present invention have made various studies and trials on the end shape of the substrate, established various conditions, and completed the present invention. The gist thereof is that, in a substrate of an optical disc for recording or reproducing information using light, a concave groove is formed on at least one surface of the outer peripheral portion of the substrate, and the height of the substrate on the side opposite to the recording area of the groove is When the height of the substrate is lower than the height of the substrate on the recording area side, and the height of the substrate on the side opposite to the recording area of the groove is c, and the difference d = a−c, the equation a> c or
An optical disk substrate satisfying the condition of 0.1 ≦ d ≦ 1.0 (mm) and having a concave groove whose longitudinal cross-sectional shape is rectangular, wedge-shaped or rectangular with a rounded corner, and information is recorded on the surface of the optical disk substrate. Alternatively, it is in an optical disc formed by forming a recording layer for reproduction.
【０００７】以下、本発明を図面によって詳細に説明す
る。本発明の光ディスク基板１および光ディスクは、図
１（ａ）、（ｂ）、（ｃ）に示すように記録層を形成す
る面の外周部に凹状の溝５を形成し、その溝５の外側の
部分の高さｃを溝の内側の部分の高さａ（元の基板の厚
さ）より低くすることで実現される。溝５の形状は縦断
面で矩形［図１（ａ）］か、楔形［図１（ｂ）］か、矩
形の角を落としてＲをつけた形［図１（ｃ）］のいずれ
も有効である。基板の高さをａ、溝５の記録領域とは反
対側の基板の高さをｃ、その差ｄ＝ａ−ｃとした時、式
ａ＞ｃまたは 0.1≦ｄ≦1.0 (mm)を満足する光ディスク
基板である。一例として直径86mmφの光ディスクの場
合、溝５の深さｂ（基板の高さａ基準）を 0.1mm以上と
することで高出力スパッタリング時の異常放電を有効に
防止することができるが、溝５の外側の部分を記録層が
形成される面より低くするために、 0.2mm以上の深さと
した方が実用上好適である。また、溝５の幅ｅも異常放
電を防ぐために 0.1mm以上とすることが望ましいが、あ
まり大きくすると記録領域として使用できる部分が小さ
くなるため最大でも１mm以下とするのがよい。The present invention will be described in detail below with reference to the drawings. In the optical disc substrate 1 and the optical disc of the present invention, as shown in FIGS. 1A, 1B, and 1C, a concave groove 5 is formed on the outer peripheral portion of the surface on which the recording layer is formed, and the outside of the groove 5 is formed. It is realized by making the height c of the portion lower than the height a of the portion inside the groove (the original thickness of the substrate). The shape of the groove 5 is either a rectangle [Fig. 1 (a)], a wedge [Fig. 1 (b)], or a rectangle with a rounded corner [Fig. 1 (c)] in vertical section. Is. When the height of the substrate is a, the height of the substrate on the side opposite to the recording area of the groove 5 is c, and the difference d = a−c, the formula a> c or 0.1 ≦ d ≦ 1.0 (mm) is satisfied. Optical disc substrate. As an example, in the case of an optical disc having a diameter of 86 mmφ, by setting the depth b of the groove 5 (based on the height a of the substrate) to be 0.1 mm or more, abnormal discharge during high-power sputtering can be effectively prevented. It is practically preferable to have a depth of 0.2 mm or more in order to make the outer portion of the layer lower than the surface on which the recording layer is formed. Further, the width e of the groove 5 is preferably 0.1 mm or more in order to prevent abnormal discharge, but if it is too large, the portion usable as a recording area becomes small, so it is preferable to be 1 mm or less at the maximum.
【０００８】溝５の外側の高さｃは、記録層が形成され
る面（元の基板表面）より 0.1mm以上低くすることで、
外周部の記録層の膜厚の減少を有効に防止することがで
きる。成膜する必要のない部分を覆い隠すマスク４をセ
ットした影響で記録層の膜厚がマスクの近くで減少する
という影響を完全になくすためには、図２のようにマス
ク４の表面が基板１の記録層２と同じ位置か、これより
低いことが望ましい。溝５については図１（ａ）〜
（ｃ）に示したような形状に加工した基板を用い、図２
に示したようにマスク４の先端部が溝５の内側に掛かる
ようにしてスパッタリング法により記録層２を成膜し、
次いで記録層２を保護するための保護コート層３を紫外
線硬化型アクリル樹脂を用いスピンコート法により塗布
する。図３に示したように保護コート層３は完全に記録
層２を覆うので保護性能は極めて良好で、その耐久性は
通常の基板を使って作製したディスクと比較して遥かに
優れたものとなる。The height c outside the groove 5 is set to be 0.1 mm or more lower than the surface (original substrate surface) on which the recording layer is formed,
It is possible to effectively prevent a decrease in the film thickness of the recording layer in the outer peripheral portion. In order to completely eliminate the effect that the film thickness of the recording layer is reduced near the mask due to the effect of setting the mask 4 that covers the portion that does not need to be formed, as shown in FIG. It is desirable that the position is the same as that of the recording layer 2 of No. 1 or lower. The groove 5 is shown in FIG.
Using the substrate processed into the shape shown in FIG.
As shown in FIG. 5, the recording layer 2 is formed by the sputtering method so that the front end of the mask 4 hangs inside the groove 5.
Next, a protective coating layer 3 for protecting the recording layer 2 is applied by a spin coating method using an ultraviolet curable acrylic resin. As shown in FIG. 3, since the protective coat layer 3 completely covers the recording layer 2, the protective performance is extremely good, and its durability is far superior to that of a disc manufactured using a normal substrate. Become.
【０００９】[0009]
【実施例】以下、本発明の実施態様を実施例を挙げて具
体的に説明するが、本発明はこれらに限定されるもので
はない。 （光ディスクの特性測定方法） １）膜厚分布：波長 632.8nmのＨe-Ｎe レーザー光線を
用いたエリプソメーターで、半径方向に 0.1mm間隔でＳ
i Ｎ単層の膜厚を測定した。 ２）反射率：光ディスク評価装置 OMS-2000 （ナカミチ
社製商品名）を用い、光の波長 780nm、回転数900rpm
で、各半径において12点反射率を測定し、その平均値を
採った。EXAMPLES The embodiments of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. (Optical disk characteristic measurement method) 1) Film thickness distribution: Ellipsometer using a He-Ne laser beam with a wavelength of 632.8 nm, S at 0.1 mm intervals in the radial direction.
The film thickness of the iN monolayer was measured. 2) Reflectance: Optical disc evaluation system OMS-2000 (trade name, manufactured by Nakamichi Co., Ltd.) is used, light wavelength 780 nm, rotation speed 900 rpm
Then, the 12-point reflectance was measured at each radius, and the average value was taken.
【００１０】（実施例１）透明ＰＣ（ポリカーボネー
ト）製直径86mmφ×厚さ1.2mmt基板を用いて、図１
（ａ）のように、記録層２を形成する面の外周部に凹状
の溝５［ａ＝1.2 、ｂ＝0.5 、ｃ＝1.0 、ｄ＝0.2 、ｅ
＝0.2 単位mm］を形成し、その溝５の外側の部分の高さ
ｃを溝の内側の部分の高さａより低くなるように成形し
た。次に溝５の外側表面が記録層２を形成する面（元の
基板表面）と同じ高さになるようにマスク４をセット
し、Ｓi Ｎの単層保護膜を形成した。Ｓi Ｎ膜はＤＣマ
グネトロンスパッタ装置を用い、Ｓi ターゲットをＡr
とＮ2 を１：１に混合したガスの雰囲気で６mTorr の圧
力下６kWの出力でスパッタして作製した。膜厚は記録領
域中心部で1000Åとなるように成膜時間を設定した。得
られたＳi Ｎ単層膜の膜厚分布を特に外周端部に注目し
てプロットした（図６参照）。図から明らかなように、
本発明の溝付き基板で作製したＳi Ｎ膜はマスク端部の
極く近くまで膜厚の減少は見られなかった（マスク端部
は溝の幅ｅ(0.2mm) の中心(0.1mm) まで掛かってい
る）。次に、基板面上にＳi Ｎ保護層（前記成膜済）、
Ｔb-Ｆe-Ｃo 層からなる光磁気記録層、さらにＳi Ｎ保
護層、Ａl 合金からなる反射層を順次積層し、光磁気デ
ィスクを作製した。このときＳi Ｎ層は６kWで、他の層
は２kWで成膜したが、どの層でもマスク４の端部での異
常放電は全く発生しなかった。本発明の溝付き基板で作
製した光磁気ディスクは、図７に示したように半径41mm
の位置でも反射率の増大は殆ど見られなかった。Example 1 Using a transparent PC (polycarbonate) substrate having a diameter of 86 mmφ and a thickness of 1.2 mmt, FIG.
As shown in (a), concave grooves 5 [a = 1.2, b = 0.5, c = 1.0, d = 0.2, e are formed on the outer periphery of the surface on which the recording layer 2 is formed.
= 0.2 unit mm], and the height c of the outer portion of the groove 5 was made lower than the height a of the inner portion of the groove. Next, the mask 4 was set so that the outer surface of the groove 5 was at the same height as the surface (original substrate surface) on which the recording layer 2 was formed, and a single-layer protective film of Si 3 N 4 was formed. For the Si N film, a DC magnetron sputtering device was used, and the Si target was Ar.
It was produced by sputtering in an atmosphere of a mixture of 1: 1 and N 2 under a pressure of 6 mTorr and an output of 6 kW. The film formation time was set so that the film thickness was 1000Å in the center of the recording area. The film thickness distribution of the obtained Si N single layer film was plotted, paying particular attention to the outer peripheral edge (see FIG. 6). As is clear from the figure,
In the SiN film produced by the grooved substrate of the present invention, no reduction in film thickness was observed up to very close to the mask edge (the mask edge is up to the center (0.1 mm) of the groove width e (0.2 mm)). Hanging). Then, a Si N protective layer (previously formed) on the substrate surface,
A magneto-optical recording layer composed of a Tb-Fe-Co layer, a Si protective layer, and a reflective layer composed of an Al alloy were sequentially laminated to manufacture a magneto-optical disk. At this time, the Si N layer was deposited at 6 kW and the other layers were deposited at 2 kW, but no abnormal discharge occurred at the end of the mask 4 in any of the layers. The magneto-optical disk manufactured by the grooved substrate of the present invention has a radius of 41 mm as shown in FIG.
Almost no increase in reflectance was observed even at the position.
【００１１】（実施例２）透明ＰＣ製直径86mmφ×厚さ
1.2mmt基板を用いて、図１（ｂ）のように、記録層２を
形成する面の外周部に楔状の溝５［ａ＝1.2 、ｂ＝0.5
、ｃ＝1.0 、ｄ＝0.2 、ｅ＝0.2 単位mm］を形成し、
その溝５の外側の部分の高さｃを溝の内側の部分の高さ
ａより低くなるように成形した。次に溝５の外側表面が
記録層２を形成する面（元の基板表面）と同じ高さにな
るようにマスク４をセットし、Ｓi Ｎの単層保護膜を形
成した。成膜条件は実施例１と同様にし、得られたＳi
Ｎ単層膜の膜厚分布を特に外周端部に注目してプロット
した（図６参照）。図から明らかなように、本発明の楔
状溝付き基板で作製したＳi Ｎ膜はマスク端部の極く近
くまで膜厚の減少は見られなかった。次に、実施例１と
同様のスパッタ条件で、基板面上にＳi Ｎ保護層（前記
成膜済）、Ｔb-Ｆe-Ｃo 層からなる光磁気記録層、さら
にＳi Ｎ保護層、Ａl 合金からなる反射層を順次積層
し、光磁気ディスクを作製した。このときにも、どの層
においてもマスク４の端部での異常放電は全く発生しな
かった。本発明の楔状溝付き基板で作製した光磁気ディ
スクは、図７に示したように半径41mmの外周部でも反射
率の増大は殆ど見られなかった。(Example 2) Made of transparent PC Diameter 86 mmφ × thickness
Using a 1.2 mmt substrate, as shown in FIG. 1B, a wedge-shaped groove 5 [a = 1.2, b = 0.5 is formed on the outer periphery of the surface on which the recording layer 2 is formed.
, C = 1.0, d = 0.2, e = 0.2 unit mm],
The height c of the outer portion of the groove 5 was formed to be lower than the height a of the inner portion of the groove. Next, the mask 4 was set so that the outer surface of the groove 5 was at the same height as the surface (original substrate surface) on which the recording layer 2 was formed, and a single-layer protective film of Si 3 N 4 was formed. The film forming conditions were the same as in Example 1, and the obtained Si
The film thickness distribution of the N single layer film was plotted, paying particular attention to the outer peripheral edge (see FIG. 6). As is clear from the figure, the SiN film produced from the substrate with wedge-shaped grooves of the present invention did not show a decrease in film thickness to the very end of the mask. Next, under the same sputtering conditions as in Example 1, a Si 3 N protective layer (the above-mentioned film was formed), a magneto-optical recording layer composed of a Tb-Fe-Co layer, a Si 3 N protective layer, and an Al alloy were formed on the substrate surface. A reflective layer was sequentially laminated to produce a magneto-optical disk. At this time as well, no abnormal discharge occurred at the end of the mask 4 in any of the layers. As shown in FIG. 7, the magneto-optical disk manufactured using the substrate with the wedge-shaped groove of the present invention showed almost no increase in reflectance even in the outer peripheral portion with a radius of 41 mm.
【００１２】（比較例）比較例として通常の溝のない基
板を用いた以外は実施例１と同様にＳi Ｎ単層膜を成膜
し、Ｓi Ｎ単層膜の膜厚分布を特に外周端部に注目して
プロットした（図６参照）。図から明らかなように、マ
スク端部から約 1.5mmの位置から徐々に膜厚が減少し、
１mmの位置では20％程度薄くなっているのが判る。次
に、実施例１と同様のスパッタ条件で基板面からＳi Ｎ
保護層（前記成膜済）、Ｔb-Ｆe-Ｃo 層からなる光磁気
記録層、さらにＳi Ｎ保護層、Ａl 合金からなる反射層
を順次積層し、光磁気ディスクを作製したが、10枚に３
枚程度の割合でマスクの端部に異常放電が発生し、基板
の外周部が黒っぽく変色しているものがあった。異常放
電が起きなかったものを選んで、種々の半径で反射率を
測定した結果（図７参照）、外周部での反射率が半径40
mm以上で異常に大きくなっていた。(Comparative Example) As a comparative example, a Si N single layer film was formed in the same manner as in Example 1 except that a normal substrate having no groove was used. The plot was focused on the area (see FIG. 6). As is clear from the figure, the film thickness gradually decreases from the position about 1.5 mm from the mask edge,
It can be seen that it is about 20% thinner at the 1 mm position. Next, under the same sputtering conditions as in Example 1, Si
A protective layer (previously formed), a magneto-optical recording layer composed of a Tb-Fe-Co layer, a Si protective layer, and a reflective layer composed of an Al alloy were sequentially laminated to form a magneto-optical disk. Three
In some cases, abnormal discharge occurred at the edge of the mask at a rate of about one sheet, and the outer peripheral portion of the substrate was discolored blackish. As a result of measuring the reflectivity at various radii by selecting the one that did not cause abnormal discharge (see Fig. 7), the reflectivity at the outer circumference is 40
It was abnormally large above mm.
【００１３】[0013]
【発明の効果】本発明の溝付き基板を用いて光ディスク
を作製すると、記録層や反射層の膜厚分布が基板外周端
部付近まで均一となり、記録トラックの最外周まで安定
した情報の記録再生領域を確保できる。また高出力で記
録層を成膜してもマスクの端部で異常放電が発生しない
ため、成膜速度を向上させることができ、光ディスクの
生産性が向上する。さらに記録トラックを現在の規格よ
り外周部まで拡大することが可能となり記録容量が増大
することとなり、産業上その利用価値は極めて高い。When an optical disk is manufactured using the grooved substrate of the present invention, the film thickness distribution of the recording layer and the reflective layer becomes uniform near the outer peripheral edge of the substrate, and stable information recording / reproduction up to the outermost periphery of the recording track. The area can be secured. Further, even if the recording layer is formed at a high output, abnormal discharge does not occur at the end portion of the mask, so that the film forming speed can be improved and the productivity of the optical disk is improved. Further, the recording track can be expanded from the current standard to the outer peripheral portion, and the recording capacity is increased, and its utility value is extremely high in industry.
【図１】本発明の外周部に溝を付けた光ディスク基板の
縦断面図（内周部は省略）である。 （ａ）矩形溝付き光ディスク基板の縦断面図である。 （ｂ）楔形溝付き光ディスク基板の縦断面図である。 （ｃ）矩形の角を落としＲを付けた形の溝付き光ディス
ク基板の縦断面図である。FIG. 1 is a vertical cross-sectional view of an optical disk substrate having a groove on the outer peripheral portion (the inner peripheral portion is omitted) of the present invention. (A) It is a longitudinal cross-sectional view of an optical disc substrate with a rectangular groove. (B) It is a longitudinal cross-sectional view of an optical disc substrate with a wedge-shaped groove. (C) It is a longitudinal cross-sectional view of a grooved optical disc substrate in which a corner of a rectangle is dropped and R is added.
【図２】矩形溝付き光ディスク基板にマスクをセット
し、記録層を成膜した状態を示す縦断面図である。FIG. 2 is a vertical cross-sectional view showing a state in which a mask is set on a rectangular grooved optical disk substrate and a recording layer is formed.
【図３】矩形溝付き光ディスク基板に保護膜を成膜し、
光ディスクとした状態を示す縦断面図である。[FIG. 3] A protective film is formed on an optical disc substrate with a rectangular groove,
It is a longitudinal cross-sectional view showing a state of an optical disc.
【図４】従来の溝なし光ディスク基板にマスクをセット
し、記録層を成膜した状態を示す縦断面図である。FIG. 4 is a vertical cross-sectional view showing a state in which a mask is set on a conventional grooveless optical disc substrate and a recording layer is formed.
【図５】光ディスクの情報領域を示す平面図である。FIG. 5 is a plan view showing an information area of an optical disc.
【図６】実施例と比較例について、Ｓi Ｎ層を成膜した
時の半径方向の膜厚分布を示すグラフである。FIG. 6 is a graph showing the film thickness distribution in the radial direction when forming a Si N layer for the example and the comparative example.
【図７】実施例と比較例について、光ディスクの半径方
向の反射率を示すグラフである。FIG. 7 is a graph showing the reflectance in the radial direction of the optical disc for the example and the comparative example.
１ 基板 ２ 記録層 ３ 保護膜 ４ マスク ５ 溝 ６ マスクする領域 ７ 記録領域 ８ 中心孔 ａ 基板の高さ ｂ 溝の深さ ｃ 基板の溝の記録領域とは反対側の高さ ｄ ａとｃとの差 ｅ 溝の幅 1 substrate 2 recording layer 3 protective film 4 mask 5 groove 6 masking area 7 recording area 8 center hole a substrate height b groove depth c height of substrate on opposite side to recording area da and c Difference with e Groove width
───────────────────────────────────────────────────── フロントページの続き (72)発明者 吉川 博樹 群馬県安中市磯部２丁目13番１号 信越化 学工業株式会社精密機能材料研究所内 (72)発明者 吉田 郁男 群馬県安中市磯部２丁目13番１号 信越化 学工業株式会社精密機能材料研究所内 (72)発明者 山村 和市 群馬県安中市磯部２丁目13番１号 信越化 学工業株式会社精密機能材料研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroki Yoshikawa Inventor Hiroki Yoshikawa 2-13-1 Isobe, Annaka City, Gunma Prefecture Shin-Etsu Chemical Co., Ltd., Institute for Precision Materials (72) Inventor Ikuo Yoshida Isobe, Gunma Prefecture 2-13-1 Shinetsu Kagaku Kogyo Co., Ltd. Precision Materials Research Laboratory (72) Inventor Kazushi Yamamura 2-13-1 Isobe, Annaka City, Gunma Shin-Etsu Kagaku Kogyo Co., Ltd.
Claims (4)
ィスクの基板において、基板の外周部の記録層の成膜さ
れる側の面に凹状の溝を形成し、該溝の記録領域とは反
対側の基板の高さを記録領域側の基板の高さより低くし
て成ることを特徴とする光ディスク基板。1. In a substrate of an optical disc for recording or reproducing information by using light, a concave groove is formed on the surface of the outer peripheral portion of the substrate on the side where a recording layer is formed, and the recording area of the groove is An optical disk substrate characterized in that the height of the substrate on the opposite side is lower than the height of the substrate on the recording area side.
の基板の高さをｃ、その差ｄ＝ａ−ｃとした時、式ａ＞
ｃまたは 0.1≦ｄ≦1.0 (単位mm) を満足する請求項１
に記載の光ディスク基板。2. When the height of the substrate is a, the height of the substrate on the side opposite to the recording area of the groove is c, and the difference d = a−c, the formula a>
c or 0.1 ≦ d ≦ 1.0 (unit: mm) is satisfied.
The optical disk substrate described in.
矩形の角を落としてＲをつけた形である請求項１または
２に記載の光ディスク基板。3. The optical disk substrate according to claim 1, wherein the concave groove has a vertical cross-sectional shape of a rectangle, a wedge, or a rectangle with a rounded corner.
ク基板の表面に情報を記録または再生するための記録層
を形成して成る光ディスク。4. An optical disc having a recording layer for recording or reproducing information formed on the surface of the optical disc substrate according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6067160A JPH07282468A (en) | 1994-04-05 | 1994-04-05 | Optical disk substrate and optical disk |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6067160A JPH07282468A (en) | 1994-04-05 | 1994-04-05 | Optical disk substrate and optical disk |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07282468A true JPH07282468A (en) | 1995-10-27 |
Family
ID=13336872
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6067160A Pending JPH07282468A (en) | 1994-04-05 | 1994-04-05 | Optical disk substrate and optical disk |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07282468A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1245363A1 (en) * | 2001-03-30 | 2002-10-02 | TDK Corporation | Stamper, mold system, recording medium substrate, recording medium, optical disc substrate, optical disc, and method for producing stamper |
| US6844045B2 (en) * | 2001-02-23 | 2005-01-18 | Tdk Corporation | Method for making optical information medium and optical information medium |
| KR100648332B1 (en) * | 1999-12-09 | 2006-11-23 | 엘지전자 주식회사 | Method for manufacturing optical disc |
-
1994
- 1994-04-05 JP JP6067160A patent/JPH07282468A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100648332B1 (en) * | 1999-12-09 | 2006-11-23 | 엘지전자 주식회사 | Method for manufacturing optical disc |
| US6844045B2 (en) * | 2001-02-23 | 2005-01-18 | Tdk Corporation | Method for making optical information medium and optical information medium |
| EP1245363A1 (en) * | 2001-03-30 | 2002-10-02 | TDK Corporation | Stamper, mold system, recording medium substrate, recording medium, optical disc substrate, optical disc, and method for producing stamper |
| US6815029B2 (en) | 2001-03-30 | 2004-11-09 | Tdk Corporation | Stamper, mold system, recording medium substrate, recording medium, optical disc substrate, optical disc, and method for producing stamper |
| US6835435B2 (en) | 2001-03-30 | 2004-12-28 | Tdk Corporation | Stamper, mold system, recording medium substrate, recording medium, optical disc substrate, optical disc, and method for producing stamper |
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