JP2778188B2 - Optical information recording / reproduction member - Google Patents
Optical information recording / reproduction memberInfo
- Publication number
- JP2778188B2 JP2778188B2 JP2061468A JP6146890A JP2778188B2 JP 2778188 B2 JP2778188 B2 JP 2778188B2 JP 2061468 A JP2061468 A JP 2061468A JP 6146890 A JP6146890 A JP 6146890A JP 2778188 B2 JP2778188 B2 JP 2778188B2
- Authority
- JP
- Japan
- Prior art keywords
- dielectric layer
- recording
- thin film
- erasing
- 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.)
- Expired - Fee Related
Links
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- Thermal Transfer Or Thermal Recording In General (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明はレーザビーム等により、情報を高密度、大容
量で記録再生及び消去できる光学情報記録再生消去部材
に関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing / erasing member capable of recording / reproducing and erasing information with a high density and a large capacity by using a laser beam or the like.
従来の技術 光ディスクメモリに関しては、TeとTeO2を主成分とす
るTeOx（０＜ｘ＜2.0）薄膜を用いた追記型のディスク
がある。さらにレーザ光により記録薄膜を加熱し、溶融
し、急冷することにより、非晶質化して情報を記録し、
またこれを加熱し徐冷することにより結晶化して消去す
ることができる材料としてS.R.Ovshinsky（エス・アー
ル・オブシンスキー）氏等のカルコゲン材料Ge15Te81Sb
2S2等が知られている。また、As2S3やAs2Se3あるいはSb
2Se3等カルコゲン元素と周期律表第Ｖ族あるいはGe等の
第IV族元素等の組み合せからなる記録薄膜等が広く知ら
れている。これらの記録薄膜をレーザ光ガイド用の溝を
設けた基板に形成し、光ディスクとして用いることがで
きる。これらのディスクにレーザ光で情報を記録し、そ
の情報を消去する方法としてはあらかじめ記録薄膜を結
晶化させておき、これに直径約１μｍに絞ったレーザ光
を情報に対応させて強度変調を施し、例えば円盤状の記
録ディスクを回転せしめて照射した場合、このピークパ
ワーレーザ光照射部位は、記録薄膜の融点以上に昇温
し、かつ急冷し、非晶質化したマークとして情報の記録
がおこなえる。またこの変調バイアスパワーレーザ光照
射部位は、記録薄膜の結晶化温度以上に昇温し、既記録
信号情報を消去する働きがありオーバライトできる。こ
のように記録薄膜はレーザ光によって融点以上に昇温
し、また結晶化温度以上に昇温されるこのため記録薄膜
の両側に耐熱性のすぐれた誘電体層を、基板および接着
層に対する保護層として設けるのが一般的である。この
誘電体層の特性、すなわち熱伝導特性あるいは熱膨張係
数等の特性によって記録・消去特性、繰り返し特性が左
右されるものである。このため誘電体の材質あるいは層
構成によって記録・消去の特性、繰り返し特性を向上さ
せることができるものである。 2. Description of the Related Art As an optical disk memory, there is a write-once disk using a TeO x (0 <x <2.0) thin film mainly composed of Te and TeO 2 . Further, the recording thin film is heated by a laser beam, melted, and rapidly cooled, thereby amorphizing and recording information,
Further, as a material which can be crystallized and erased by heating and gradually cooling it, chalcogen material Ge 15 Te 81 Sb of SROvshinsky (S.R.
2 S 2 and the like are known. In addition, As 2 S 3 or As 2 Se 3 or Sb
Recording thin films and the like comprising a combination of a chalcogen element such as 2 Se 3 and a group IV element such as group V or Ge of the periodic table are widely known. These recording thin films can be formed on a substrate provided with a groove for laser light guide and used as an optical disk. As a method of recording information on these discs with laser light and erasing the information, a recording thin film is crystallized in advance, and the laser light focused to a diameter of about 1 μm is subjected to intensity modulation according to the information. For example, when rotating and irradiating a disk-shaped recording disk, this peak power laser beam irradiated portion can be heated to a temperature equal to or higher than the melting point of the recording thin film and rapidly cooled, and information can be recorded as an amorphous mark. . Further, the modulated bias power laser beam irradiated portion has a function of erasing already recorded signal information by heating to a temperature higher than the crystallization temperature of the recording thin film, and can be overwritten. As described above, the recording thin film is heated to a temperature higher than the melting point by the laser beam and higher than the crystallization temperature. Therefore, a dielectric layer having excellent heat resistance is provided on both sides of the recording thin film as a protective layer for the substrate and the adhesive layer. It is common to provide as. The recording / erasing characteristics and the repetition characteristics are influenced by the characteristics of the dielectric layer, that is, the characteristics such as the heat conduction characteristics or the thermal expansion coefficient. Therefore, the recording / erasing characteristics and the repetition characteristics can be improved by the dielectric material or the layer structure.
発明が解決しようとする課題 記録薄膜を加熱昇温し、溶融急冷非晶質化および加熱
昇温徐冷結晶化の手段を用いる情報記録および消去可能
なオーバライト記録媒体における第一の課題は消去特
性、第二の課題は記録消去の繰り返し特性である。消去
特性についてはTeを含む非晶質膜は、その融点は代表的
なもので400℃から900℃と広い温度範囲にあるこれらの
記録薄膜にレーザ光を照射し、昇温徐冷することにより
結晶化が行える。この温度は一般的に融点より低い結晶
化温度領域である。またこの結晶化した膜に高いパワー
レベルのレーザ光をあて、その融点以上に加熱するとそ
の部分は溶融し急冷し、再び非晶質化してマークが形成
できる。記録マークとして非晶質化を選ぶと、このマー
クは記録薄膜が溶融し、急冷されて形成されるものであ
るから、冷却速度が速いほど非晶質状態の均一なものが
得られ信号振幅が向上する。冷却速度が遅い場合はマー
クの中心と周辺では非晶質化の程度に差が発生する。次
に結晶化消去に際しては、レーザ光の照射により、既に
記録が行われている非晶質マーク部を結晶化温度以上に
昇温し、結晶化させてこのマークを消去する。この時、
マークの非晶質状態が均一な場合は、均一に結晶化され
やすくなり消去特性が向上するが、マークの非晶質状態
が不均一な場合は、結晶化消去の状態が不均一となって
消去特性が低下すると言った課題があった。記録・消去
の繰り返し特性については急速な加熱、冷却の多数回の
繰り返しによるディスク基板あるいは誘電体層の熱的な
損傷がある。ディスク基板あるいは誘電体層が熱的な損
傷を受けた場合、記録・消去の繰り返しにおいて、ノイ
ズの増大を生じ特性の劣化が発生するという課題があっ
た。本発明の目的は記録消去特性に優れ、繰り返し特性
の安定な光ディスクを提供することである。Problems to be Solved by the Invention The first problem in an information recording and erasable overwrite recording medium using a means of heating and raising the temperature of a recording thin film, melting and quenching amorphization, and heating and gradual cooling and crystallization is a first problem. The second problem is the repetition characteristics of recording and erasing. Regarding the erasing characteristics, the amorphous film containing Te has a typical melting point and is irradiated with a laser beam over a wide temperature range from 400 ° C to 900 ° C. Crystallization can be performed. This temperature is generally a crystallization temperature region lower than the melting point. When a laser beam having a high power level is applied to the crystallized film and heated to a temperature higher than its melting point, the portion is melted, rapidly cooled, and then becomes amorphous again to form a mark. If amorphization is selected as the recording mark, this mark is formed by melting the recording thin film and quenching, so that the faster the cooling rate, the more uniform the amorphous state is obtained and the signal amplitude is increased. improves. When the cooling rate is low, there is a difference in the degree of amorphization between the center and the periphery of the mark. Next, at the time of crystallization erasing, the amorphous mark portion on which recording has already been performed is heated to a temperature higher than the crystallization temperature by laser beam irradiation and crystallized to erase this mark. At this time,
When the amorphous state of the mark is uniform, the mark is easily crystallized and the erasing characteristics are improved, but when the amorphous state of the mark is non-uniform, the state of crystallization and erasing becomes non-uniform. There is a problem that the erasing characteristics are deteriorated. Regarding the repetitive characteristics of recording / erasing, there is thermal damage to the disk substrate or the dielectric layer due to rapid repetition of heating and cooling many times. When the disk substrate or the dielectric layer is thermally damaged, there is a problem that noise is increased and the characteristics are deteriorated in repetition of recording / erasing. An object of the present invention is to provide an optical disc having excellent recording / erasing characteristics and stable repetition characteristics.
課題を解決するための手段 本発明は記録薄膜と、該記録薄膜の両側に誘電体層を
積層した光学情報記録再生消去部材であって、透明基板
の一方の面に、第一の誘電体層、記録薄膜、第二の誘電
体層、第二の誘電体層と異なる材質の第三の誘電体層、
反射層を順次形成し、第二の誘電体層と第三の誘電体層
を合わせた膜厚が第一の誘電体層の膜厚よりも薄く、し
かも第三の誘電体層を第一、第二の誘電体層より、熱膨
張係数の小さい材質にする、あるいは第二の誘電体層を
第一、第三の誘電体層より熱膨張係数の小さな材料で構
成にするものである。Means for Solving the Problems The present invention is a recording thin film, and an optical information recording / reproducing and erasing member in which a dielectric layer is laminated on both sides of the recording thin film, wherein a first dielectric layer is provided on one surface of the transparent substrate. , A recording thin film, a second dielectric layer, a third dielectric layer of a different material from the second dielectric layer,
A reflective layer is sequentially formed, and the total thickness of the second dielectric layer and the third dielectric layer is smaller than the thickness of the first dielectric layer, and the third dielectric layer is the first, A material having a smaller coefficient of thermal expansion than the second dielectric layer, or a material having a smaller coefficient of thermal expansion than the first and third dielectric layers is used for the second dielectric layer.
作用 すなわち熱膨張係数の小さな誘電体層を第二の誘電体
層と反射層の間に設けて第三の誘電体層を形成するこ
と、あるいは記録薄膜と第三の誘電体層の間に設けて第
二の誘電体層を形成することによって、記録・消去時の
記録薄膜の熱による記録薄膜の両側の誘電体層の熱変形
を小さくすることができるものである。これらの誘電体
層の熱変形は永久的なものではなく、レーザ光が照射さ
れた瞬間だけ加熱されて膨張し、レーザが照射されてい
ない時は冷却されて元の状態に戻ることを繰り返すもの
である。この誘電体層の脈動がディスクの回転方向が一
定であるために、記録薄膜をディスクの回転方向に移動
させることになって、繰り返し特性を劣化させることに
なるものである。これに対して熱膨張係数の小さな誘電
体層を一層設けることによって、記録薄膜の両側の誘電
体層の熱変形を小さくすることができて繰り返し特性を
改善することができるものである。The effect, that is, providing a dielectric layer having a small coefficient of thermal expansion between the second dielectric layer and the reflective layer to form a third dielectric layer, or providing between the recording thin film and the third dielectric layer By forming the second dielectric layer in this manner, thermal deformation of the dielectric layers on both sides of the recording thin film due to heat of the recording thin film during recording / erasing can be reduced. The thermal deformation of these dielectric layers is not permanent, but is repeated by heating and expanding only at the moment of laser beam irradiation, and cooling and returning to the original state when laser beam is not irradiated. It is. Since the pulsation of the dielectric layer keeps the rotation direction of the disk constant, the recording thin film is moved in the rotation direction of the disk, thereby deteriorating the repetition characteristics. On the other hand, by providing one dielectric layer having a small coefficient of thermal expansion, thermal deformation of the dielectric layers on both sides of the recording thin film can be reduced, and the repetition characteristics can be improved.
また、反射層と記録薄膜との間に設ける第二の誘電体
層及び第三の誘電体層の合計の膜厚を、透明基板と記録
薄膜との間に設ける第一の誘電体層の膜厚よりも薄くす
る構成により、反射層は記録薄膜で吸収したエネルギー
に起因する熱を散逸する熱拡散機能も発揮するため、記
録薄膜と反射層との距離の短縮化に伴い、記録薄膜の熱
の散逸方向がより一定化され記録マークの形成が均一化
されると共に、記録薄膜の冷却速度が向上し記録薄膜の
非晶質状態の形成効率が高まり、記録信号振幅が増大す
る。In addition, the total thickness of the second dielectric layer and the third dielectric layer provided between the reflective layer and the recording thin film is equal to the thickness of the first dielectric layer provided between the transparent substrate and the recording thin film. By making the thickness thinner than the thickness, the reflective layer also exhibits a heat diffusion function to dissipate heat caused by energy absorbed by the recording thin film. The direction in which the recording marks are dissipated is made more uniform, the formation of the recording marks is made uniform, the cooling rate of the recording thin film is improved, the efficiency of forming the amorphous state of the recording thin film is increased, and the recording signal amplitude is increased.
実施例 以下、本発明の一実施例を図面に基づいて説明する。
第１図において１はディスク基板でポリカーボネイト等
の樹脂基板からなっている。このディスク基板１はあら
かじめレーザ光案内用の溝を形成した樹脂基板あるいは
フォトポリマーを用いた、いわゆる2P法で溝を形成した
ガラス板、ガラス板に直接溝を形成した基板であっても
よい。２は第一の誘電体層で耐熱性に優れたZnSを主成
分とした材質からなっており膜厚は約150nmである。３
は記録薄膜でTe−Ge−Sbからなる合金薄膜であり膜厚は
約30nmである。４は第二の誘電体層で、第一の誘電体層
と同じ材質からなっており膜厚は約20nmである。５は第
三の誘電体層で、熱膨張係数の小さいSiO2（熱膨張係数
0.45×10-6k-1）からなっており膜厚は約20nmである。
６はAlからなる反射層で膜厚は約60nmである。これらの
薄膜の形成方法としては、真空蒸着あるいはスパッタ法
が使用できる。７は保護板で接着剤８によってディスク
基板１に貼り合わせている。第１図の構成において記録
・消去及び再生は矢印９の方向より、情報に応じて強度
変調を施したレーザ光を照射して、また反射光を検出し
て行うものである。ここで前記したように熱膨張係数の
小さな第三の誘電体層５を設けていることによって、記
録・消去の繰り返しで発生する第一、第二の誘電体層
２、４の熱変形による脈動を抑制することになって繰り
返し特性を大幅に改善することができるものである。
尚、第二の誘電体層４と第三の誘電体層５の材質が入れ
かわっても同様の効果を得られるものである。また第二
の誘電体層４と第三の誘電体層５の膜厚を合わせて約40
nmと薄くしているが、これによって熱拡散層となる反射
層６と記録薄膜３が近くなり記録・消去時の記録薄膜３
の熱が急速に反射層６に伝達されることになり、記録薄
膜３を急冷する上で効果があるものであり、この記録薄
膜３と反射層６の間の誘電体層の材質と膜厚で冷却速度
を制御することができるものである。本実施例のディス
ク構成で、外形130nm、1800rmp回転、線速度8m/secでf1
＝3.43MHzの信号、f2＝1.0MHzの信号のオーバーライト
特性を測定した。オーバーライトは、１個のサークルス
ポットで直径約１μｍのレーザ光により、高いパワーレ
ベル16mW,低いパワーレベル8mWの間の変調で、高いパワ
ーレベルで非晶質化マークを形成し、低いパワーレベル
で非晶質化マークを結晶化して消去する同時消録の方法
で行った。この結果、記録信号のC/N比としては、55dB
以上が得られ、消去特性として、オーバライト消去率30
dB以上が得られた。オーバライトの繰り返し特性につい
ては、特にビットエラーレイトの特性を測定した結果、
1000000サイクル以上劣化が見られなかった。Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a disk substrate made of a resin substrate such as polycarbonate. The disk substrate 1 may be a resin substrate in which a groove for guiding laser light is formed in advance, a glass plate using photopolymer, in which a groove is formed by a so-called 2P method, or a substrate in which a groove is directly formed in a glass plate. Reference numeral 2 denotes a first dielectric layer made of a material mainly composed of ZnS having excellent heat resistance and a thickness of about 150 nm. 3
Is a recording thin film, which is an alloy thin film made of Te-Ge-Sb and has a thickness of about 30 nm. Reference numeral 4 denotes a second dielectric layer, which is made of the same material as the first dielectric layer and has a thickness of about 20 nm. 5 is a third dielectric layer, which has a small thermal expansion coefficient of SiO 2 (thermal expansion coefficient).
0.45 × 10 −6 k −1 ), and the film thickness is about 20 nm.
Reference numeral 6 denotes a reflective layer made of Al and has a thickness of about 60 nm. As a method for forming these thin films, vacuum evaporation or sputtering can be used. Reference numeral 7 denotes a protective plate which is bonded to the disk substrate 1 with an adhesive 8. In the configuration shown in FIG. 1, recording, erasing, and reproduction are performed by irradiating a laser beam subjected to intensity modulation according to information in the direction of arrow 9 and detecting reflected light. Since the third dielectric layer 5 having a small coefficient of thermal expansion is provided as described above, pulsation due to thermal deformation of the first and second dielectric layers 2 and 4 generated by repetition of recording / erasing is provided. Is suppressed, and the repetition characteristics can be greatly improved.
The same effect can be obtained even if the materials of the second dielectric layer 4 and the third dielectric layer 5 are interchanged. The total thickness of the second dielectric layer 4 and the third dielectric layer 5 is about 40
nm, the reflection layer 6 serving as a heat diffusion layer and the recording thin film 3 become close to each other, and the recording thin film 3 at the time of recording / erasing is reduced.
Is rapidly transferred to the reflective layer 6, which is effective in rapidly cooling the recording thin film 3. The material and thickness of the dielectric layer between the recording thin film 3 and the reflective layer 6 are effective. Can control the cooling rate. In the disk configuration of the present embodiment, f1 at an outer diameter of 130 nm, 1800 rpm rotation, and a linear velocity of 8 m / sec.
Overwrite characteristics of a signal of 3.43 MHz and a signal of f2 = 1.0 MHz were measured. Overwriting is performed by laser light with a diameter of about 1 μm in one circle spot, modulation between a high power level of 16 mW and a low power level of 8 mW to form an amorphous mark at a high power level and at a low power level. Simultaneous recording was performed by crystallizing and erasing the amorphous mark. As a result, the C / N ratio of the recording signal is 55 dB
As a result, the overwriting erasure rate of 30
dB or more was obtained. Regarding the overwrite repetition characteristics, the results of measuring the bit error rate characteristics in particular,
No deterioration was observed over 1,000,000 cycles.
発明の効果 以上説明したように記録薄膜と反射層の間の薄層の誘
電体層を２層にして、いずれかの１層に熱膨張係数の小
さい材料を選び、第二、第三の誘電体層を合わせた膜厚
を第一の誘電体層よりも薄くすることによって以下の効
果を得られるものである。Effects of the Invention As described above, two thin dielectric layers between the recording thin film and the reflective layer are used, and a material having a small coefficient of thermal expansion is selected for one of the two layers. The following effects can be obtained by making the combined film thickness of the body layers smaller than that of the first dielectric layer.
（１）記録・消去時の誘電体層の熱変形による脈動を小
さくできることによって繰り返し特性が向上する。(1) Pulsation due to thermal deformation of the dielectric layer at the time of recording / erasing can be reduced, thereby improving the repetition characteristics.
（２）記録信号振幅が増大し、C/N比は55dB以上に向上
する。(2) The recording signal amplitude increases, and the C / N ratio improves to 55 dB or more.
（３）記録マークが均一化し、オーバライト消去率が30
dB以上になり消去特性が向上する。(3) Uniform recording marks and overwrite erasure rate of 30
dB or more, and the erasing characteristics are improved.
第１図は本発明の一実施例における光学情報記録再生消
去部材の一部省略断面図である。 １……ディスク基板、２……第一の誘電体層、３……記
録薄膜、４……第二の誘電体層、５……第三の誘電体
層、６……反射層、７……接着剤、８……保護板。FIG. 1 is a partially omitted sectional view of an optical information recording / reproducing and erasing member according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Disc substrate, 2 ... First dielectric layer, 3 ... Recording thin film, 4 ... Second dielectric layer, 5 ... Third dielectric layer, 6 ... Reflective layer, 7 ... ... adhesive, 8 ... protective plate.
フロントページの続き (72)発明者 河原 克巳 大阪府門真市大字門真1006番地 松下電 器産業株式会社内 (56)参考文献 特開 昭62−102441（ＪＰ，Ａ) 特開 平２−56746（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) G11B 7/24Continuation of front page (72) Inventor Katsumi Kawahara 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-62-102441 (JP, A) JP-A-2-56746 (JP) , A) (58) Field surveyed (Int.Cl. 6 , DB name) G11B 7/24
Claims (3)
し、溶融し、急冷して非晶質化する性質と、非晶質の状
態を昇温することにより結晶化する性質とを有する記録
薄膜、 第二の誘電体層、 前記第二の誘電体層と異なる材質の第三の誘電体層、 反射層を順次形成し、 前記第二の誘電体層と前記第三の誘電体層を合わせた膜
厚が前記第一の誘電体層の膜厚よりも薄く、 前記第二の誘電体層及び前記第三の誘電体層の内、何れ
か一方の誘電体層の熱膨張係数が他の誘電体層の熱膨張
係数よりも小さい材質を適用することを特徴とする光学
情報記録再生消去部材。1. A first dielectric layer, on one surface of a transparent substrate, is irradiated with a laser beam to absorb its energy, raise its temperature, melt, and rapidly cool to become amorphous. A recording thin film having a property of being crystallized by raising the temperature of an amorphous state, a second dielectric layer, a third dielectric layer made of a material different from that of the second dielectric layer, and a reflective layer. Forming, the combined thickness of the second dielectric layer and the third dielectric layer is smaller than the thickness of the first dielectric layer, the second dielectric layer and the third An optical information recording / reproducing and erasing member, wherein a material is used in which one of the dielectric layers has a thermal expansion coefficient smaller than that of another dielectric layer.
内、熱膨張係数が小さい誘電体層の材質にSiO2を用い、
該熱膨張係数が小さい誘電体層以外の誘電体層の材質に
ZnSを用いることを特徴とする請求項１記載の光学情報
記録再生消去部材。2. The method according to claim 2, wherein the second dielectric layer or the third dielectric layer is made of SiO 2 as a material of the dielectric layer having a small thermal expansion coefficient.
For materials of dielectric layers other than the dielectric layer having a small coefficient of thermal expansion
2. The optical information recording / reproducing and erasing member according to claim 1, wherein ZnS is used.
いることを特徴とする請求項１記載の光学情報記録再生
消去部材。3. The optical information recording / reproducing and erasing member according to claim 1, wherein a material made of Te, Ge, Sb is used as the recording thin film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2061468A JP2778188B2 (en) | 1990-03-13 | 1990-03-13 | Optical information recording / reproduction member |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2061468A JP2778188B2 (en) | 1990-03-13 | 1990-03-13 | Optical information recording / reproduction member |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03263626A JPH03263626A (en) | 1991-11-25 |
| JP2778188B2 true JP2778188B2 (en) | 1998-07-23 |
Family
ID=13171912
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2061468A Expired - Fee Related JP2778188B2 (en) | 1990-03-13 | 1990-03-13 | Optical information recording / reproduction member |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2778188B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5712833A (en) * | 1993-12-28 | 1998-01-27 | Ogihara; Noriyuki | Durable magneto-optical disk having a rare earth-transition amorphous magneto-optical layer |
| JPH08287515A (en) * | 1995-02-13 | 1996-11-01 | Matsushita Electric Ind Co Ltd | Optical information recording medium |
| EP0854476A1 (en) * | 1995-10-03 | 1998-07-22 | Asahi Kasei Kogyo Kabushiki Kaisha | Optical information recording medium, method of manufacturing the medium, and target used for manufacturing the medium |
| EP1178477A1 (en) | 1997-04-25 | 2002-02-06 | Teijin Limited | Phase change optical recording medium and process for manufacturing same |
| KR100271567B1 (en) * | 1997-08-14 | 2000-11-15 | 구자홍 | Phase changing disk |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62102441A (en) * | 1985-10-30 | 1987-05-12 | Fujitsu Ltd | Optical recording medium and its manufacture |
| JPH0256746A (en) * | 1988-08-19 | 1990-02-26 | Matsushita Electric Ind Co Ltd | Information carrier disk |
-
1990
- 1990-03-13 JP JP2061468A patent/JP2778188B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03263626A (en) | 1991-11-25 |
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