JPH0337840A - Phase change type optical disk - Google Patents
Phase change type optical diskInfo
- Publication number
- JPH0337840A JPH0337840A JP1173753A JP17375389A JPH0337840A JP H0337840 A JPH0337840 A JP H0337840A JP 1173753 A JP1173753 A JP 1173753A JP 17375389 A JP17375389 A JP 17375389A JP H0337840 A JPH0337840 A JP H0337840A
- Authority
- JP
- Japan
- Prior art keywords
- film
- phase change
- recording medium
- medium layer
- substrate
- 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
- 230000003287 optical effect Effects 0.000 title claims abstract description 22
- 239000000758 substrate Substances 0.000 claims abstract description 34
- 239000000463 material Substances 0.000 claims abstract description 27
- 230000001681 protective effect Effects 0.000 claims abstract description 25
- 239000010408 film Substances 0.000 abstract description 75
- 238000000034 method Methods 0.000 abstract description 14
- 239000011521 glass Substances 0.000 abstract description 7
- 239000000126 substance Substances 0.000 abstract description 6
- 239000010409 thin film Substances 0.000 abstract description 6
- 238000002834 transmittance Methods 0.000 abstract description 6
- 238000004544 sputter deposition Methods 0.000 abstract description 5
- 238000001771 vacuum deposition Methods 0.000 abstract description 2
- 238000010030 laminating Methods 0.000 abstract 1
- 238000001579 optical reflectometry Methods 0.000 abstract 1
- 238000004519 manufacturing process Methods 0.000 description 12
- 239000002184 metal Substances 0.000 description 11
- 230000006866 deterioration Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000007774 longterm Effects 0.000 description 3
- 238000004528 spin coating Methods 0.000 description 3
- 238000007738 vacuum evaporation Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 150000004703 alkoxides Chemical class 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 230000001678 irradiating effect Effects 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 150000004075 acetic anhydrides Chemical class 0.000 description 1
- 150000007942 carboxylates Chemical class 0.000 description 1
- 238000012824 chemical production Methods 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000002178 crystalline material Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 150000002902 organometallic compounds Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- -1 oxychlorides Chemical class 0.000 description 1
- 229920005668 polycarbonate resin Polymers 0.000 description 1
- 239000004431 polycarbonate resin Substances 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 238000003852 thin film production method Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本光明は、レーザ光の照射により情報の記録・再生を行
う相変化型光ディスクに関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a phase-change optical disc that records and reproduces information by irradiating it with laser light.
［従来技術］
従来、ディスク基板上に保護膜が形成されるとともに、
その保護膜上にレーザ光の照射により結晶質と非晶質と
の間で可逆的或いは非可逆的に相変化する記録媒体層が
設けられている相変化型光ディスクが知られている。か
かるディスクは、レーザ光の照射による温度変化により
可逆的或いは非可逆的に結晶質と非晶質との間で相変化
し、この２つの層の間の光反射率、光透過率の違いを利
用して情報の記録・再生を行うものである。そして、前
記ディスク基板には、一般に渦巻状若しくは同心円状に
凹凸が形成され情報を記録するトラックが規定されるよ
うになっており、前記保護膜や相変化記録媒体層もその
凹凸に倣った凹凸状を威しているのが普通である。[Prior Art] Conventionally, a protective film is formed on a disk substrate, and
A phase change type optical disk is known in which a recording medium layer is provided on the protective film, and the recording medium layer undergoes a reversible or irreversible phase change between crystalline and amorphous states by irradiation with laser light. Such a disk undergoes a phase change between crystalline and amorphous reversibly or irreversibly due to temperature changes caused by laser beam irradiation, and the difference in light reflectance and light transmittance between these two layers is It is used to record and reproduce information. The disk substrate generally has concavities and convexities formed in a spiral or concentric form to define tracks for recording information, and the protective film and phase change recording medium layer also have concavities and convexities that follow the convexities. It is normal for the situation to be intimidating.
［発明か解決しようとする課題］
しかしながら、相変化型記録媒体層が凹凸形状を為して
いると、その段差部分で膜厚が不均一になるとともに、
段差部分と平坦部分とで結晶状態が歪むため、均一な光
反射率乃至光透過率が得られなくなって雑音成分が増大
し、記録特性が損なわれるという問題があった。また、
段差部分の膜形状が急激に変化する部分から記録媒体層
の酸化等の劣化が生じやすいため、長期にわたる信頼性
が低下するという問題があった。[Problems to be Solved by the Invention] However, when the phase change recording medium layer has an uneven shape, the film thickness becomes uneven at the stepped portions, and
Since the crystal state is distorted between the stepped portion and the flat portion, there is a problem that uniform light reflectance or light transmittance cannot be obtained, noise components increase, and recording characteristics are impaired. Also,
There is a problem in that long-term reliability is reduced because deterioration such as oxidation of the recording medium layer is likely to occur at the step portion where the film shape changes rapidly.
本発明は、上述した問題点を解決するためになされたも
のであり、その目的とするところは、ｌ記録媒体層を略
均一の厚さで略平坦に形成することにより記録特性の優
れた高品位な相変化型光ディスクを提供することにある
。The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a high recording medium with excellent recording characteristics by forming a recording medium layer with a substantially uniform thickness and substantially flat. The objective is to provide a high-quality phase change optical disc.
［課題を解決するための手段］
この目的を達成するために本発明の相変化型光ディスク
ではディスク基板上に保護膜が形成されているとともに
、その保護膜上にレーザ光の照射により結晶質から非晶
質に可逆的或いは非可逆的に相変化記録媒体層が形成さ
れており、前記保護膜の前記相変化記録媒体層側の表面
が平坦に形成され、その保護膜の平坦な表面の上に相変
化記録媒体層が略均一の厚さで平坦に設けられている。[Means for Solving the Problems] In order to achieve this object, in the phase change optical disc of the present invention, a protective film is formed on the disc substrate, and the crystalline material is removed from the crystalline state by irradiating the protective film with laser light. A phase change recording medium layer is formed on an amorphous material reversibly or irreversibly, the surface of the protective film on the phase change recording medium layer side is formed flat, and the surface of the protective film on the flat surface of the protective film is flat. The phase change recording medium layer is provided flat with a substantially uniform thickness.
尚、上記保護膜の相変化記録媒体層側の表面は必ずしも
厳密に平坦である必要はなく、急峻な凹凸がなくなる程
度であっても差支えない。また、かかる保護膜は、例え
ば回転塗布法により液体ガラスをトラッキング用反射材
の形成されたディスク基板上に塗布して固化したものに
よって容易に構成される。Incidentally, the surface of the above-mentioned protective film on the phase change recording medium layer side does not necessarily have to be strictly flat, and may have no steep irregularities. Further, such a protective film can be easily formed by applying, for example, liquid glass onto a disk substrate on which a tracking reflective material is formed by a spin coating method and then solidifying the coating.
［作用］
上記の構成を有する本発明の相変化型光ディスクによれ
ば、相変化記録媒体層が略均一の厚さで平坦であるため
レーザ光が記録媒体に安定に照射され、均一な記録特性
が得られると共に光反射率。[Function] According to the phase change optical disk of the present invention having the above configuration, since the phase change recording medium layer is flat with a substantially uniform thickness, the laser beam is stably irradiated onto the recording medium, resulting in uniform recording characteristics. is obtained as well as light reflectance.
光透過率の安定性が向上する。更に膜の段差による雑音
の発生や膜の劣化が生じず、再生特性が向上すると共に
長期信頼性も向−ヒする。Stability of light transmittance is improved. Further, noise generation and membrane deterioration due to differences in membrane level do not occur, and reproduction characteristics are improved and long-term reliability is also improved.
更にディスク基板上にトラッキング用反射材が設けられ
ており、この反射材と記録媒体層とにおける回折を利用
し、よく知られているプッシュプル法により安定したト
ラッキングサーボを実現することかできる。Further, a tracking reflective material is provided on the disk substrate, and by utilizing diffraction between this reflective material and the recording medium layer, stable tracking servo can be realized by the well-known push-pull method.
［実施例］
以下、本発明の一実施例を図面に基づいて詳細に説明す
る。[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.
第１図は、本発明の一実施例である相変化型光デイスク
１０の要部断面図であり、この相変化型光デイスク１０
は、ディスク基板１２上（図では下側）に干渉膜１４Ｊ
Ｉ］変化型記録媒体層１６゜及び保護膜１８を順次積層
したものである。FIG. 1 is a sectional view of a main part of a phase change optical disk 10 which is an embodiment of the present invention.
is an interference film 14J on the disk substrate 12 (lower side in the figure).
I] A variable recording medium layer 16° and a protective film 18 are sequentially laminated.
ディスク基板１２は、ガラス基板２０にＡＡ。The disk substrate 12 has a glass substrate 20 made of AA.
Ｔａ等の金属製反射材２２を渦巻状若しくは同心円状に
固着したもので、例えば第２図に示されているようにし
て作成される。即ち、先ず第２図の（ａ）に示されてい
るように平坦なガラス基板２０を用意し、その−面に、
（ｂ）に示されているように上記反射材２２を構成する
金属膜２４をスパソタリングや蒸着等の手段で形成し、
更にレジスト２６をその金属膜２４上に塗布する。次に
、レーザ露光法等により、（Ｃ）に示されているように
上記レジスト２６を渦巻状若しくは同心円状に取り除い
た後、エツチングによって（ｄ）に示されているように
金属膜２４を除去することにより、その金属膜２４の一
部が前記反射材２２としてガラス基板２０上に残される
。そして、その反射材２２上に残されたレジスト２６を
除去することにより、（ｅ）に示されているディスク基
板１２が作成される。上記反射材２２は、ガラス基板２
０側から照射されるレーザ光を反射して情報を記録すべ
きトラックを規定するものである。It is made by fixing a metal reflective material 22 such as Ta in a spiral or concentric shape, for example, as shown in FIG. 2. That is, first, as shown in FIG. 2(a), a flat glass substrate 20 is prepared, and on its negative side,
As shown in (b), a metal film 24 constituting the reflective material 22 is formed by means such as spa sottering or vapor deposition,
Furthermore, a resist 26 is applied onto the metal film 24. Next, the resist 26 is removed in a spiral or concentric manner as shown in (C) using a laser exposure method or the like, and then the metal film 24 is removed by etching as shown in (d). As a result, a part of the metal film 24 is left on the glass substrate 20 as the reflective material 22. Then, by removing the resist 26 left on the reflective material 22, the disk substrate 12 shown in (e) is produced. The reflective material 22 is a glass substrate 2
This is to define a track on which information is to be recorded by reflecting a laser beam irradiated from the 0 side.
また、上記ディスク基板１２上に設けられる干渉膜１４
は、特許請求の範囲における保護膜に相当するもので、
化学変化から相変化型記録媒体層１６を保護するととも
に、光の干渉により干渉膜１４の両面で反射する反射光
を打ち消し、記録感度を上げる作用を為すものであり、
５ｉ０２（二酸化硅素）等の化学的に安定な透明の酸化
物にて構成される。かかる干渉膜１４は、本実施例では
その作製手段により第１膜１４ａ及び第２″ａ１４ｂか
ら構成されており、第１膜１４ａは、回転塗布性により
ディスク基１ｆ１２の反射材２２側を七向きにして回転
させつつＳｔ等のアルコキシドを供給して塗布し、これ
を４００℃程度の高温べ−りを用いて固化させたもので
ある。これにより、反射材２２間の線間が埋められ、第
１膜１４ａのディスク基板１２と反対側の面は、ディス
ク基板１２の凹凸に拘らず略平坦となる。また、第２膜
１４ｂは、スパッタリング、真空蒸着等の物理的薄膜作
製法、或いはＣＶ Ｄ （ＣｈｅＩｌｉｃａｌ Ｖａｐ
ｏｒ Ｄｅｐ。Further, an interference film 14 provided on the disk substrate 12
corresponds to the protective film in the claims,
It protects the phase-change recording medium layer 16 from chemical changes, and also has the effect of canceling out the reflected light reflected on both sides of the interference film 14 due to light interference and increasing the recording sensitivity.
It is composed of a chemically stable transparent oxide such as 5i02 (silicon dioxide). In this embodiment, the interference film 14 is composed of a first film 14a and a second film 14b due to its manufacturing method, and the first film 14a is coated by spin coating so that the reflective material 22 side of the disk base 1f12 faces seven directions. While rotating the reflective material 22, an alkoxide such as St is supplied and applied, and this is solidified using a high temperature base of about 400°C.As a result, the spaces between the lines between the reflective materials 22 are filled. The surface of the first film 14a opposite to the disk substrate 12 is substantially flat regardless of the unevenness of the disk substrate 12.The second film 14b is formed by a physical thin film manufacturing method such as sputtering or vacuum evaporation, or by CVD. D (CheIlical Vap
or Dep.
５ｌｔｉｏｎ）法等の化学的薄膜作製法により、上記第
１膜１４ａと同じ物質をその第１膜１４ａ上に形成した
もので、干渉膜１４が予め定められた所定の厚さとなる
ように調整される。相変化型記録媒体層１６は、Ｉｎ−
５ｅを主成分とする材料や、ＴｅＯｘを主成分とする材
料をスパッタリングや真空蒸着等により０．１μｍ以下
の厚さで上記干渉膜１４のディスク基板１２と反対側の
表面が略平坦に形成されているところから、この相変化
型記録媒体層１６は、略均一な厚さで平坦に設けられる
。The same material as the first film 14a is formed on the first film 14a by a chemical thin film manufacturing method such as the 5ltion) method, and the interference film 14 is adjusted to have a predetermined thickness. Ru. The phase change recording medium layer 16 is made of In-
The surface of the interference film 14 on the side opposite to the disk substrate 12 is formed substantially flat with a thickness of 0.1 μm or less by sputtering or vacuum deposition of a material containing 5e as a main component or a material containing TeOx as a main component. Therefore, the phase change recording medium layer 16 is provided flat with a substantially uniform thickness.
保護膜１８は、上記相変化型記録媒体層１６を化学変化
から保護するためのもので前記干渉膜１４と同様に５ｉ
０２等の化学的に安定な透明の酸化物にて構成される。The protective film 18 is for protecting the phase change recording medium layer 16 from chemical changes, and is made of 5i like the interference film 14.
It is made of chemically stable transparent oxide such as 02.
かかる保護膜１８も、その作製手段により第１膜１８ａ
及び第２膜１８ｂから構成されており、第１膜１８ａは
、スパッタリング、真空蒸着等の物理的薄膜作製法、或
いはＣＶＤ法等の化学的作製法によって作製されている
。This protective film 18 also has a first film 18a depending on its manufacturing method.
and a second film 18b, and the first film 18a is produced by a physical thin film production method such as sputtering or vacuum evaporation, or a chemical production method such as a CVD method.
また、第２膜１８ｂは、回転塗布法によって上記第１膜
１８ａと同じ物質をその第１膜１８ａ上に上乗せし、高
温ベークを用いて固化させたもので、保護膜１８が予め
定められた所定の厚さとなるように調整される。この膜
厚は、例えば１μｍ以下に定められる。The second film 18b is obtained by applying the same substance as the first film 18a on the first film 18a by a spin coating method and solidifying it by baking at a high temperature, so that the protective film 18 has a predetermined shape. The thickness is adjusted to a predetermined thickness. This film thickness is set to, for example, 1 μm or less.
尚、前記干渉膜１４の第２膜１４ｂ、相変化型記録媒体
層１６．及び保護膜１８の第１膜１８ａは、真空中から
取り出すことなく連続して作製される。そして、かかる
相変化型光デイスク１０は、そのディスク基板１２を通
してレーザ光が相変化型記録媒体層１６に照射されると
、熱の効果により可逆的に或いは非可逆的に非晶質から
結晶質に変化する。情報の記録は、この結晶状態の差に
起因する光反射率、光透過率の違いを利用して行う。Note that the second film 14b of the interference film 14, the phase change recording medium layer 16. The first film 18a of the protective film 18 is continuously manufactured without being taken out of the vacuum. When the phase change recording medium layer 16 is irradiated with a laser beam through the disk substrate 12, the phase change optical disk 10 reversibly or irreversibly changes from amorphous to crystalline due to the effect of heat. Changes to Information is recorded by utilizing the difference in light reflectance and light transmittance caused by the difference in crystalline state.
この相変化型記録媒体の特徴は、（１）オーバーライド
が可能（２）Ｃ／Ｎが高い（３）ヘッド構造が簡単等で
ある。The characteristics of this phase change recording medium include (1) overwriting is possible, (2) high C/N, and (3) simple head structure.
ここで、本実施例の相変化型光デイスク１０は、相変化
型記録媒体層１６が略均一の厚さで平坦であるため、安
定な反射特性、透過特性が得られ、その記録特性が大幅
に向上する。因に、従来の相変化型光ディスクは、第３
図に示す様にディスク基板１２゛には一体に凹凸が設け
られている一方、干渉膜１４−１保：！ｊｌ膜１８゛は
、それぞれスパッタリング、真空蒸着等の単一の薄膜作
製法により作製されている。即ち、相変化型記録媒体層
１６がディスク基板１２゛の凹凸に対応した凹凸形状を
為していたため、均一な反射特性、透過特性が得られな
くて記録・特性が損なわれるという問題があった。Here, in the phase change type optical disk 10 of this embodiment, since the phase change type recording medium layer 16 is flat and has a substantially uniform thickness, stable reflection characteristics and transmission characteristics can be obtained, and the recording characteristics are significantly improved. improve. Incidentally, conventional phase change optical discs
As shown in the figure, the disk substrate 12' is integrally provided with unevenness, while the interference film 14-1 is protected by:! The jl films 18' are each manufactured by a single thin film manufacturing method such as sputtering or vacuum evaporation. That is, since the phase-change recording medium layer 16 had an uneven shape corresponding to the unevenness of the disk substrate 12, there was a problem that uniform reflection and transmission characteristics could not be obtained and the recording and characteristics were impaired. .
また、本実施例の製造方法においては、相変化型記録媒
体層１６．及びその両面に位置する干渉膜１４の第２膜
１４ｂ、保護膜１８の第１膜１８ａが、真空中から取り
出すことなく連続して作製されるため、相変化型記録媒
体層１６の化学変化が良好に防止されるとともに、相変
化光デイスク１０を能率的に製造できる利点がある。Further, in the manufacturing method of this embodiment, the phase change recording medium layer 16. Since the second film 14b of the interference film 14 and the first film 18a of the protective film 18 located on both sides of the interference film 14 are continuously manufactured without being taken out of the vacuum, chemical changes in the phase change recording medium layer 16 are prevented. This has the advantage that it can be effectively prevented and the phase change optical disk 10 can be manufactured efficiently.
また、相変化型記録媒体層１６は平坦であるが、トラッ
キング用反射材２２がディスク基板１２に形成されてい
るため、従来の光ディスクと同様によく知られているプ
ッシュプル法或いは３ビーム法等により容易にトラッキ
ングを行うことができる。Further, although the phase change recording medium layer 16 is flat, since the tracking reflective material 22 is formed on the disk substrate 12, the well-known push-pull method, three-beam method, etc. This makes tracking easier.
以上、本発明の一実施例を図面に基づいて詳細に説明し
たが、本発明は他の態様で実施することもできる。Although one embodiment of the present invention has been described above in detail based on the drawings, the present invention can also be implemented in other embodiments.
例えば、前記実施例ではディスク基板１２がガラス基板
２０と反射材２２とから構成されているが、反射材２２
を設ける替わりにガラス長、１ｆ２０に膚を形成したり
、ガラス基［２０の替わりにアクリル樹脂、ポリカーボ
ネート樹脂、ポリオレフィン樹脂等の合成樹脂等を用い
たりすることも可能である
また、上記反射材２２は金属製であるが、窒化物等の金
属以外の物質を用いることもできる。For example, in the embodiment described above, the disk substrate 12 is composed of the glass substrate 20 and the reflective material 22, but the reflective material 22
Instead of providing the reflective material 22, it is also possible to form a skin on the glass length 1f20, or to use a synthetic resin such as acrylic resin, polycarbonate resin, or polyolefin resin instead of the glass base 20. is made of metal, but materials other than metal such as nitride can also be used.
また、前記干渉膜１４．保護膜１８は、その作製手段に
よりそれぞれ第１膜１４ａ、１８ａ及び第２Ｈ１４ｂ、
１８ｂから構成されているが、それぞれ単一の薄膜作製
法により１回で干渉膜１４゜保護膜１８を作製するよう
にしても、或いは複数の薄膜作製法により３層以上に分
けて作製するようにしても差支えない。Further, the interference film 14. The protective film 18 is formed into first films 14a, 18a and second film 14b, respectively, depending on its manufacturing method.
18b, the interference film 14 and the protective film 18 may be fabricated in one go using a single thin film fabrication method, or they may be fabricated in three or more layers using multiple thin film fabrication methods. It doesn't matter if you do that.
また、上記干渉膜１４．保護膜１８の材質は必要に応じ
て適宜変更され得る。Further, the interference film 14. The material of the protective film 18 may be changed as necessary.
また、干渉膜１４は、金属アルコキシド、金属アセチル
アセテート、金属カルボキシレート等の金属有機化合物
及び硝酸塩、オキシ塩化物、塩化物等の金属無機化合物
を出発金属化合物としてゾルゲル法にて作成しても良い
。Alternatively, the interference film 14 may be created by a sol-gel method using metal organic compounds such as metal alkoxides, metal acetylacetates, metal carboxylates, and metal inorganic compounds such as nitrates, oxychlorides, and chlorides as starting metal compounds. .
また、相変化型記録媒体層の材質についても特に限定し
ない。Further, the material of the phase change recording medium layer is not particularly limited either.
また、前述した相変化型光デイスク１０の製造方法はあ
くまでも一例であり、他の種々の製造方法を採用するこ
とができる。要するに、干渉膜１４の相変化型記録媒体
層１６側の表面に急峻な凹凸がなく、相変化型記録媒体
層１６が略均一の厚さで平坦に設けられれば良いのであ
る。Furthermore, the method for manufacturing the phase change optical disk 10 described above is just an example, and various other manufacturing methods may be employed. In short, it is sufficient that the surface of the interference film 14 on the phase change recording medium layer 16 side has no steep irregularities and that the phase change recording medium layer 16 is provided flat with a substantially uniform thickness.
また、前記実施例の相変化型光デイスク１０はディスク
基板１２側からレーザ光が照射されるようになっている
が、ディスク基板１２と反対側からレーザ光が入射され
る形式の相変化型光ディスクにも本発明は同様に適用さ
れ得る。Further, although the phase change optical disk 10 of the above embodiment is configured to be irradiated with laser light from the disk substrate 12 side, a phase change optical disk in which the laser beam is incident from the side opposite to the disk substrate 12 The present invention can be similarly applied to.
以上詳述したことから明らかなように、本発明によれば
、相変化型記録媒体が略均一の厚みで平坦であるため、
レーザ光が記録媒体に安定に照射され、その結果、光反
射率、光透過率の安定性が向上し、その記録特性が大幅
に向上する。更に、膜の段差が原因となる雑音の発生や
膜の劣化が生じずＣ／Ｎ等の再生特性が向上すると共に
長期信頼性も向上する。As is clear from the detailed description above, according to the present invention, since the phase change recording medium is flat with a substantially uniform thickness,
The recording medium is stably irradiated with laser light, and as a result, the stability of light reflectance and light transmittance is improved, and its recording characteristics are significantly improved. Further, noise generation and film deterioration caused by the step difference in the film do not occur, and reproduction characteristics such as C/N are improved, and long-term reliability is also improved.
第１図から第舎図までは本発明を具体化した実施例を示
すもので、第１図は、本発明の一実施例である相変化型
光ディスクの要部断面図、第２図は、第１図の相変化型
光ディスクにおけるディスク基板の作製方法の一例を説
明する図、第３図は従来の相変化型光ディスクの一例を
説明する要部断面図である。
図中、１０は相変化型光ディスク、１２はディスク基板
、１４は干渉膜、１６は相変化型記録媒体層、１８は保
３膜、２２はトラッキング用反射材である。1 to 2 show embodiments embodying the present invention. FIG. 1 is a cross-sectional view of a main part of a phase change optical disc which is an embodiment of the present invention, and FIG. FIG. 1 is a diagram illustrating an example of a method for manufacturing a disk substrate in a phase change optical disk, and FIG. 3 is a sectional view of a main part illustrating an example of a conventional phase change optical disk. In the figure, 10 is a phase change type optical disk, 12 is a disk substrate, 14 is an interference film, 16 is a phase change type recording medium layer, 18 is a protective film, and 22 is a tracking reflective material.
Claims (1)
、該保護膜上にレーザ光の照射により結晶質から非晶質
へ或いはその逆へ、非可逆的或いは可逆的に相変化する
記録媒体層が設けられている相変化型光ディスクであっ
て、 前記保護膜の前記記録媒体層側の表面が平坦に形成され
、該相変化記録媒体層が略均一の厚さで平坦に設けられ
ていることを特徴とする相変化型光ディスク。 ２、前記第１項記載の相変化型光ディスクにおいて、前
記ディスク基板が透明基板上とその上に形成されたトラ
ッキング用反射材とから成ることを特徴とする相変化型
光ディスク。[Claims] 1. A protective film is formed on the disk substrate, and the protective film is irreversibly or reversibly changed from crystalline to amorphous or vice versa by irradiation with laser light. A phase change optical disc provided with a phase change recording medium layer, wherein the surface of the protective film on the recording medium layer side is formed flat, and the phase change recording medium layer has a substantially uniform thickness and is flat. A phase change optical disc characterized by being provided in. 2. The phase-change optical disc according to item 1, wherein the disc substrate comprises a transparent substrate and a tracking reflective material formed on the transparent substrate.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1173753A JPH0337840A (en) | 1989-07-05 | 1989-07-05 | Phase change type optical disk |
| US07/432,457 US5089358A (en) | 1988-11-05 | 1989-11-06 | Optical recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1173753A JPH0337840A (en) | 1989-07-05 | 1989-07-05 | Phase change type optical disk |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0337840A true JPH0337840A (en) | 1991-02-19 |
Family
ID=15966498
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1173753A Pending JPH0337840A (en) | 1988-11-05 | 1989-07-05 | Phase change type optical disk |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0337840A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6427049A (en) * | 1987-04-22 | 1989-01-30 | Hitachi Ltd | Optical disk, substrate for optical disk and its production |
| JPS6439643A (en) * | 1987-08-05 | 1989-02-09 | Toppan Printing Co Ltd | Optical recording medium |
-
1989
- 1989-07-05 JP JP1173753A patent/JPH0337840A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6427049A (en) * | 1987-04-22 | 1989-01-30 | Hitachi Ltd | Optical disk, substrate for optical disk and its production |
| JPS6439643A (en) * | 1987-08-05 | 1989-02-09 | Toppan Printing Co Ltd | Optical recording medium |
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