JPH0559495B2 - - Google Patents
Info
- Publication number
- JPH0559495B2 JPH0559495B2 JP60086872A JP8687285A JPH0559495B2 JP H0559495 B2 JPH0559495 B2 JP H0559495B2 JP 60086872 A JP60086872 A JP 60086872A JP 8687285 A JP8687285 A JP 8687285A JP H0559495 B2 JPH0559495 B2 JP H0559495B2
- Authority
- JP
- Japan
- Prior art keywords
- layer
- recording
- substrate
- protective layer
- optical
- 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.)
- Expired - Lifetime
Links
- 239000010410 layer Substances 0.000 claims description 36
- 239000011241 protective layer Substances 0.000 claims description 21
- 239000000758 substrate Substances 0.000 claims description 17
- 230000003287 optical effect Effects 0.000 claims description 14
- 239000012790 adhesive layer Substances 0.000 claims description 11
- 230000001681 protective effect Effects 0.000 claims description 8
- 239000010408 film Substances 0.000 description 7
- 230000005415 magnetization Effects 0.000 description 6
- 239000000853 adhesive Substances 0.000 description 4
- 230000001070 adhesive effect Effects 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000010409 thin film Substances 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- -1 moisture Substances 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 241000569510 Spino Species 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 238000003848 UV Light-Curing Methods 0.000 description 1
- GEIAQOFPUVMAGM-UHFFFAOYSA-N ZrO Inorganic materials [Zr]=O GEIAQOFPUVMAGM-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 1
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- BIXHRBFZLLFBFL-UHFFFAOYSA-N germanium nitride Chemical compound N#[Ge]N([Ge]#N)[Ge]#N BIXHRBFZLLFBFL-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000007373 indentation Methods 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 1
- 229910003465 moissanite Inorganic materials 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- PLDDOISOJJCEMH-UHFFFAOYSA-N neodymium oxide Inorganic materials [O-2].[O-2].[O-2].[Nd+3].[Nd+3] PLDDOISOJJCEMH-UHFFFAOYSA-N 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 238000005240 physical vapour deposition Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 229910052950 sphalerite Inorganic materials 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 229910001256 stainless steel alloy Inorganic materials 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 229910052984 zinc sulfide Inorganic materials 0.000 description 1
Landscapes
- Optical Record Carriers And Manufacture Thereof (AREA)
Description
【発明の詳細な説明】
（発明の技術分野）
本発明は、高密度情報記録媒体として注目され
ているレーザデイスク、ビデオデイスク、デジタ
ルオーデイオデイスク、光磁気デイスク、
DRAWデイスクなどレーザビームによつて再生
又は記録再生又は消去記録再生を行なう光デイス
ク特にその構造に関する。Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to laser disks, video disks, digital audio disks, magneto-optical disks, which are attracting attention as high-density information recording media.
The present invention relates to optical discs, such as DRAW discs, in which reproduction, recording and reproduction, or erasing and recording are performed using a laser beam, and particularly to the structure thereof.
（発明の背景）
情報社会の進展に伴なつて高密度でランダムア
クセス可能な情報記録媒体の要求が高まつてい
る。そのため、既にビデオデイスク デジタルオ
ーデイオデイスク、などの光デイスクが実用化さ
れている。(Background of the Invention) With the development of the information society, the demand for high-density, randomly accessible information recording media is increasing. Therefore, optical disks such as video disks and digital audio disks have already been put into practical use.
そのうち、再生専用の光デイスクでは、平坦な
表面を有する基板デイスクに、信号ピツトと呼ば
れる「島状突起」又は「くぼみ」が同心円状又は
渦巻き状に点々と形成されており、情報はこのピ
ツトの有無又はピツト長によつて記録されてい
る。１つのピツトは例えば幅0.5ミクロン×長さ
0.9〜３ミクロン×深さ（又は高さ）0.1ミクロン
という微細な寸法を有するもので、トラツク間隔
も例えば1.6ミクロンと微細である。 Among these, read-only optical discs have "island-like protrusions" or "indentations" called signal pits dotted in a concentric or spiral shape on a substrate disc with a flat surface, and information is transmitted through these pits. It is recorded by presence or absence or pit length. One pit is, for example, 0.5 microns wide x length
It has minute dimensions of 0.9 to 3 microns x depth (or height) of 0.1 microns, and the track spacing is also as small as, for example, 1.6 microns.
また、記録可能な光デイスクでは、微小径に絞
つた一定強度のレーザビームを、高速で移動する
媒体に、所望のビツト長Ｌに応じて所定時間（パ
ルス幅とも呼ばれる）tpの間照射し、それにより
生じる熱によりピツトを形成する。例えば、(イ)熱
によつて媒体を溶解又は昇華させ、くぼみを作
り、このくぼみをピツトとするもの、(ロ)熱によつ
て相転移を起こさせ、光学的性質例えば屈折率、
反射率が元の状態とは異なる区域を作り、この区
域をピツトとするもの、(ハ)熱によつて媒体の上向
き又は下向きに揃つた垂直磁化の保磁力を低下さ
せ、同時に反転磁場を印加して磁化の向きを反転
させ、その上でレーザビームの照射をとめて磁化
の向きが元の状態とは反対の区域を作り、この区
域をピツトとするもの（光磁気記録）などがあ
る。 In addition, in the case of a recordable optical disc, a laser beam of constant intensity narrowed to a minute diameter is irradiated onto a medium moving at high speed for a predetermined time (also called pulse width) tp depending on the desired bit length L. The heat generated thereby forms a pit. For example, (a) one in which a medium is melted or sublimated by heat to create a depression and this depression becomes a pit; (b) a phase transition is caused by heat and optical properties such as refractive index,
Creating an area where the reflectance is different from the original state and using this area as a pit; (c) reducing the coercive force of the perpendicular magnetization aligned upward or downward in the medium by heat, and applying a reversal magnetic field at the same time. There is a method (magneto-optical recording) in which the direction of magnetization is reversed, and then the laser beam irradiation is stopped to create an area where the direction of magnetization is opposite to the original state, and this area is used as a pit (magneto-optical recording).
このような光デイスクは、本質的にはデイスク
状の基板１上に情報記録層２を形成したものであ
り、なかには基板１の表面層と記録層２が兼用し
ているものもある。 Such an optical disk essentially has an information recording layer 2 formed on a disk-shaped substrate 1, and in some optical disks, the surface layer of the substrate 1 and the recording layer 2 serve as both.
ともあれ、記録層２が露出したままでは破損、
変質等を受けるので保護のため、ガラス、プラス
チツク等の保護板が必要となる。場合によつて
は、同じように基板１上に記録層２と無機保護層
３を積層してなる第２基板を、保護層３側を接着
面として接着して保護板を兼用させることもあ
る。保護板、第２基板のような板状部材を本明細
書では総称して「平板」ということにするが、記
録層２の上に「平板」を接着するには接着剤が必
要となる。 In any case, if recording layer 2 is left exposed, it will be damaged.
Because it is subject to deterioration, a protective plate made of glass, plastic, etc. is required to protect it. In some cases, a second substrate made by laminating a recording layer 2 and an inorganic protective layer 3 on the substrate 1 may also be used as a protective plate by bonding the second substrate with the protective layer 3 side as the adhesive surface. . In this specification, plate-like members such as the protective plate and the second substrate will be collectively referred to as a "flat plate", but an adhesive is required to adhere the "flat plate" onto the recording layer 2.
しかしながら、記録層２の上に直接接着剤層４
を設けると、接着剤中に含まれる水分、有機溶
剤、モノマー、酸素等が記録層２を劣化させる
（特に記録層２が遷移金属−希土類合金の垂直磁
化膜からなる場合には、特に酸化劣化され易い）。 However, the adhesive layer 4 is directly placed on the recording layer 2.
If the recording layer 2 is made of a perpendicularly magnetized film of a transition metal-rare earth alloy, moisture, organic solvents, monomers, oxygen, etc. contained in the adhesive will deteriorate the recording layer 2. ).
そのため、本発明者は記録層２の上に無機保護
層３例えば真空蒸着、スパツタリング、イオンプ
レーデイング、CVD、PVD等の真空薄膜形成技
術（薄膜法と呼ばれる）で形成したSiO2、SiO、
Al2O3、ZrO2、TiO2、HfO2、AlN、Si3N4、
ZnS、MgF2、CeO2、Or2O3、Nd2O3、Ta2O5、
SiC、Cr、Ti、Pt、Pd、窒化ゲルマニウム、Al、
Au、Ag、In、ステンレス合金、蒸着用ガラス、
などの単層又は多層薄膜３を設けることを先に着
想した。 Therefore, the present inventors formed an inorganic protective layer 3 on the recording layer 2 using vacuum thin film forming techniques (referred to as thin film methods) such as vacuum evaporation, sputtering, ion plating, CVD, and PVD, such as SiO 2 , SiO,
Al 2 O 3 , ZrO 2 , TiO 2 , HfO 2 , AlN, Si 3 N 4 ,
ZnS , MgF2 , CeO2 , Or2O3 , Nd2O3 , Ta2O5 ,
SiC, Cr, Ti, Pt, Pd, germanium nitride, Al,
Au, Ag, In, stainless steel alloy, glass for vapor deposition,
It was previously conceived to provide a single-layer or multi-layer thin film 3 such as.
ところで接着剤で保護板、第２基板等の「平
板」を接着する場合、どうしても接着剤層に気泡
がはいり易く、特に先の無機保護層を設けた場合
に気泡がはいり易く、その界面に気泡が存在する
と、レーザビームが乱反射されたり、気泡が断熱
層となつて放熱量が変わり、気泡のない所に比べ
て記録層の温度が上昇し、そのため、誤再生、再
生不能、誤記録、記録不能、誤消去、消去不能な
どの問題があつた。 By the way, when bonding a "flat plate" such as a protective plate or a second substrate with an adhesive, air bubbles tend to form in the adhesive layer, and especially when the inorganic protective layer described above is provided, air bubbles tend to form at the interface. If there is, the laser beam will be diffusely reflected, the bubbles will act as a heat insulating layer, and the amount of heat dissipated will change, causing the temperature of the recording layer to rise compared to a place without bubbles, resulting in erroneous playback, inability to play, erroneous recording, and recording. There were problems such as being impossible to erase, erasing by mistake, and being unable to erase.
（発明の目的）
従つて、本発明の目的は、無機保護層の上に
「平板」を接着した場合に、接着剤層と無機保護
層との界面に気泡のない光デイスクを提供するこ
とにある。(Objective of the Invention) Therefore, the object of the present invention is to provide an optical disk that does not have air bubbles at the interface between the adhesive layer and the inorganic protective layer when a "flat plate" is adhered onto the inorganic protective layer. be.
（発明の概要）
本発明者は、当初気泡を押し出すことを着想し
たが、そのために接着剤層４に圧力をかけて流動
させると、元来弱い無機保護層３及び情報記録層
２が破損してしまつた。(Summary of the Invention) The inventor initially conceived of extruding air bubbles, but when applying pressure to the adhesive layer 4 to make it flow, the inorganic protective layer 3 and information recording layer 2, which are originally weak, were damaged. It was.
本発明の特徴は、無機保護層３と接着剤層４と
の間に、該保護層との界面に気泡のないプレコー
ト層６を設けたことにある。 A feature of the present invention is that a bubble-free precoat layer 6 is provided between the inorganic protective layer 3 and the adhesive layer 4 at the interface with the protective layer.
このようなプレコート層６は、現在のところ唯
一スピンコート法により塗料を塗布することによ
り得られる。プレコート層の厚さは１〜15μもあ
れば十分である。 Such a precoat layer 6 can currently only be obtained by applying a paint using a spin coating method. A thickness of 1 to 15 μm is sufficient for the precoat layer.
本発明に於いて、基板１としては、ガラス、プ
ラスチツク、セラミツク、アルミニウムなどが使
用されるが、基板の上には、予め、凹凸状のトラ
ツクが形成された薄い成形体層、誘電体層、反射
層、干渉膜、他の保護膜などが形成されていても
よい。基板１の上には情報記録層２が形成され
る。情報記録層２としては、光デイスクタイプに
より先に述べた種々のものがある。例えば、光磁
気デイスクでは、記録層２として常法に従い垂直
磁化膜を形成する。垂直磁化膜としては、例えば
TbFe、GdFe、DyFe、GdCo、HoCo、
GdTbFe、GdDyFe、TbDyFe、GdFeCo、
GdDyFeCo、GdTbFeCoなどの希土類−遷移金
属アモルフアス合金が主として使用される。記録
層２の上には、上述の無機保護層３を設ける。 In the present invention, glass, plastic, ceramic, aluminum, etc. are used as the substrate 1. On the substrate, a thin molded layer on which uneven tracks are formed in advance, a dielectric layer, A reflective layer, an interference film, another protective film, etc. may be formed. An information recording layer 2 is formed on the substrate 1. As the information recording layer 2, there are various types as described above depending on the optical disc type. For example, in a magneto-optical disk, a perpendicular magnetization film is formed as the recording layer 2 according to a conventional method. For example, as a perpendicular magnetization film,
TbFe, GdFe, DyFe, GdCo, HoCo,
GdTbFe, GdDyFe, TbDyFe, GdFeCo,
Rare earth-transition metal amorphous alloys such as GdDyFeCo and GdTbFeCo are mainly used. On the recording layer 2, the above-mentioned inorganic protective layer 3 is provided.
保護層３の上には、上述のプレコート層６を設
け、そして接着剤層４を介して「平板」５を接着
すると、本発明の光デイスクが得られる。 The above-mentioned precoat layer 6 is provided on the protective layer 3, and the "flat plate" 5 is adhered via the adhesive layer 4 to obtain the optical disk of the present invention.
以下、実施例により本発明を具体的に説明する
が、本発明は、これに限られるものではない。 EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.
（実施例）
直径200mm、厚さ1.2mmのデイスク状ガラス基板
１の上に、まず保護層７として600Åの厚さの
SiC層を設け、その上に記録層２として、厚さ
500ÅのTbFe／厚さ500ÅのGdFeCoからなる２
層垂直磁化膜を形成させた。(Example) First, a protective layer 7 with a thickness of 600 Å was deposited on a disk-shaped glass substrate 1 with a diameter of 200 mm and a thickness of 1.2 mm.
A SiC layer is provided, and a recording layer 2 is formed on top of the SiC layer with a thickness of
2 consisting of 500 Å TbFe/500 Å thick GdFeCo
A perpendicular magnetization film was formed.
続いて同一真空中で無機保護層３として厚さ
1000ÅのSiO2更に厚さ500ÅのAlを真空蒸着し
た。 Subsequently, the thickness of the inorganic protective layer 3 was increased in the same vacuum.
1000 Å thick SiO 2 and 500 Å thick Al were vacuum deposited.
次にその上にスピノコート法により紫外線硬化
型塗料、商品名：フジハード（藤倉化成株式会社
製）を乾燥膜厚10μの厚さに塗布し、紫外線を照
射して硬化させて、プレコート層６を形成させ
た。このプレコート層は保護層３との界面に気泡
は全く存在しなかつた。最後に保護板として基板
１と同一形状寸法のポリカーボネート製「平板」
５を接着した。接着には紫外線硬化型の商品名：
NOA61（ノーランド・プロダクツ・インコーポレ
イテツド社製）を用いた。 Next, an ultraviolet curable paint, product name: Fuji Hard (manufactured by Fujikura Kasei Co., Ltd.), is applied on top of it using the spino coating method to a dry film thickness of 10 μm, and is cured by irradiation with ultraviolet rays to form the precoat layer 6. I let it happen. This precoat layer had no bubbles at the interface with the protective layer 3. Finally, a polycarbonate “flat plate” with the same shape and dimensions as substrate 1 is used as a protective plate.
5 was glued. Product name of UV curing type for adhesion:
NOA61 (manufactured by Norland Products, Inc.) was used.
こうして製造された光デイスクについて光磁気
記録再生装置で記録、再生を行なつたところ、記
録エラーは、ほとんどなかつた。それに対して、
本発明のプレコート層６を設けなかつたものは、
記録エラーが著しかつた。 When recording and reproduction were performed on the optical disc thus manufactured using a magneto-optical recording and reproducing apparatus, there were almost no recording errors. On the other hand,
In the case where the precoat layer 6 of the present invention is not provided,
There were significant recording errors.
（発明の効果）
以上の通り、本発明によれば、プレコート層を
設けることで無機保護層と接着剤層との界面に生
じ易い気泡が皆無となり、そのため誤再生、再生
不能、誤記録、記録不能、誤消去、消去不能など
の問題が解決される。(Effects of the Invention) As described above, according to the present invention, by providing a precoat layer, there are no bubbles that are likely to be generated at the interface between the inorganic protective layer and the adhesive layer, and therefore, there is no possibility of erroneous reproduction, unreproducibility, erroneous recording, or recording. Problems such as inability, mistaken erasure, and inability to erase are solved.
第１図は、実施例の光デイスクの概略縦断面図
である。
〔主要部分の符号の説明〕、１……基板、２…
…情報記録層、３……無機保護層、４……接着剤
層、５……「平板」又は保護板又は第２基板、６
……プレコート層。
FIG. 1 is a schematic vertical cross-sectional view of an optical disk according to an example. [Explanation of symbols of main parts], 1... Board, 2...
... Information recording layer, 3 ... Inorganic protective layer, 4 ... Adhesive layer, 5 ... "flat plate" or protective plate or second substrate, 6
...Pre-coat layer.
Claims (1)
と、その上に設けられた無機保護層３とその上に
接着剤層４を介して接着された保護板５又は「基
板１とその上に設けられた情報記録層２と、その
上に設けられた無機保護層３とからなる第２基板
５」とからなる光デイスクに於いて、 前記保護層３と接着剤層４との間に、前記保護
層３との界面に気泡の存在しないプレコート層６
を設けたことを特徴とする光デイスク。[Claims] 1. A substrate 1 and an information recording layer 2 provided thereon.
and an inorganic protective layer 3 provided thereon and a protective plate 5 bonded thereon via an adhesive layer 4, or a "substrate 1, an information recording layer 2 provided thereon, and a protection plate 5 bonded thereon via an adhesive layer 4". In the optical disk comprising a second substrate 5 consisting of an inorganic protective layer 3 and an inorganic protective layer 3, a pre-coat is provided between the protective layer 3 and the adhesive layer 4 in which no air bubbles are present at the interface with the protective layer 3. layer 6
An optical disk characterized by being provided with.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60086872A JPS61246942A (en) | 1985-04-23 | 1985-04-23 | Optical disk |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60086872A JPS61246942A (en) | 1985-04-23 | 1985-04-23 | Optical disk |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61246942A JPS61246942A (en) | 1986-11-04 |
| JPH0559495B2 true JPH0559495B2 (en) | 1993-08-31 |
Family
ID=13898912
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60086872A Granted JPS61246942A (en) | 1985-04-23 | 1985-04-23 | Optical disk |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61246942A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR950004613B1 (en) * | 1989-06-07 | 1995-05-03 | 미쯔비시 덴끼 가부시끼가이샤 | Ignition device for internal combustion engine |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5361303A (en) * | 1976-11-15 | 1978-06-01 | Hitachi Ltd | Formation method of protecting layer of recording member |
| JPS58108044A (en) * | 1981-12-22 | 1983-06-28 | Pioneer Electronic Corp | Optical disk |
| JPS6042095A (en) * | 1983-08-19 | 1985-03-06 | Hitachi Ltd | Information recording member |
| JPS615794A (en) * | 1984-06-15 | 1986-01-11 | Sumitomo Chem Co Ltd | Production of optically active benzyl alcohol derivative |
| JPS6180532A (en) * | 1984-09-28 | 1986-04-24 | Toshiba Corp | Optical disk |
-
1985
- 1985-04-23 JP JP60086872A patent/JPS61246942A/en active Granted
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5361303A (en) * | 1976-11-15 | 1978-06-01 | Hitachi Ltd | Formation method of protecting layer of recording member |
| JPS58108044A (en) * | 1981-12-22 | 1983-06-28 | Pioneer Electronic Corp | Optical disk |
| JPS6042095A (en) * | 1983-08-19 | 1985-03-06 | Hitachi Ltd | Information recording member |
| JPS615794A (en) * | 1984-06-15 | 1986-01-11 | Sumitomo Chem Co Ltd | Production of optically active benzyl alcohol derivative |
| JPS6180532A (en) * | 1984-09-28 | 1986-04-24 | Toshiba Corp | Optical disk |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61246942A (en) | 1986-11-04 |
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