JPS61133059A - Optical disk consisting of color tone recording alloy - Google Patents

Abstract

PURPOSE:To permit the rewriting to an Ag-Zn color tone recording alloy with low power by providing the 1st layer having an endothermic or heat accumulative function on a plastic plate having a reinforcing function, providing the 2nd layer having a color tone recording function thereon and providing the 3rd layer to protect the same. CONSTITUTION:For example, polycarbonate, epoxy and polymethyl methacrylate resin are used for a 1.2-1.5mm thick plastic substrate 10. The endothermic layer 1 is formed by depositing metallic Bi, Cr or the like by evaporation on the substrate to several 10 nm thickness. Said layer converts the energy from laser light to heat energy and transmits the same to the next color tone recording alloy layer 2. The 1st layer can function as an antireflection film if the thickness (d) of said layer is so designed as to attain nd=lambda/4 with respect to the wavelength lambda of the laser light. The conversion efficiency is thereby improved (where n: refractive index). The color tone recording alloy 2 is formed by depositing, for example, Ag-40% Zn to about 50 nm thickness on the 1st layer by evaporation. The laser light is irradiated to said layer from the substrate 10 side.

Description

【発明の詳細な説明】 〔発明の利用分野〕 本発明は書換え可能な光ディスクに係υ、特に合金の相
変態を利用した色調記録合金を用いた光ディスクに好適
な構造に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a rewritable optical disk, and particularly to a structure suitable for an optical disk using a tone recording alloy that utilizes phase transformation of the alloy.

〔発明の背景〕[Background of the invention]

従来の装置は特開昭５９−１５１３４４号に示すように
補強基板としてアクリル樹脂等を用い、光記録材料とし
ては非Ｔｅ系の材料を用いた構造になっていた。しかし
、出願人の先願に係る特願昭５９−４２０７９号、又は
特願昭５９−１３０６１１号の合金として例えばＡｇ−
Ｚｎ系合金のように反射率が大きく、自身では比較的書
換え温度が高く、熱伝導率の大きい材料への低パワー書
込みに対する配慮はされていなかった。As shown in Japanese Unexamined Patent Publication No. 59-151344, a conventional device has a structure in which an acrylic resin or the like is used as a reinforcing substrate and a non-Te based material is used as an optical recording material. However, for example, Ag-
No consideration was given to low-power writing to materials such as Zn-based alloys, which have a high reflectance, a relatively high rewriting temperature, and a high thermal conductivity.

〔発明の目的〕[Purpose of the invention]

本発明の目的は前記した特徴のあるＡｇ−Ｚｎ系色調記
録合金への書換えが低パワーで行える光ディスクの構造
を提供するものである。An object of the present invention is to provide an optical disc structure that allows rewriting to the Ag-Zn color tone recording alloy having the characteristics described above with low power.

〔発明の概要〕[Summary of the invention]

基本的には、色調記録合金へのレーザーパワー吸収を高
め、放散を防止する多層膜構造とし、各材料は次の特性
を具備するものとする。Basically, the color tone recording alloy has a multilayer structure that increases laser power absorption and prevents dissipation, and each material has the following characteristics.

（１）　　Ａ　ｇ　−Ｚ　ｎ系色調記録合金はそれ自身
比較的反射率が大きく、約ａｏｏｃの加熱・急冷プロセ
スで反射率が第１（ａ）図に示すような変化を呈し、徐
冷プロセスで元に戻る特性を有するもので、熱伝導率が
約０．５〔ｃａｔ／ｃＷ＆・Ｃ−３〕と大きく、熱膨脹
率が約ｚｓｘｉｏ−’ｔ−ｃ−１〕と金属としては比較
的大きいものである（第２層）。(1) The A g -Z n-based color tone recording alloy itself has a relatively high reflectance, and the reflectance changes as shown in Figure 1(a) during the heating and rapid cooling process of about aooc; It has the property of returning to its original state with a high thermal conductivity of approximately 0.5 [cat/cW&・C-3], and a relatively large coefficient of thermal expansion for a metal of approximately zsxio-'t-c-1]. (Second layer)

Ｃ）　基板であるプラスチック板は前記記録合金膜を補
強し、前記記録膜への吸熱、蓄熱を助けるため、書換え
用光源であるレーザー光の波長に対して透過率が高く、
熱放散防止のため熱伝導率が小さく、そして、書込み温
度で劣化しない耐熱性を有するものであること。C) The plastic plate that is the substrate has a high transmittance to the wavelength of the laser light that is the rewriting light source in order to reinforce the recording alloy film and help absorb and store heat in the recording film.
It must have low thermal conductivity to prevent heat dissipation, and must have heat resistance that does not deteriorate at writing temperatures.

（３）第１層はレーザー光のエネルギーを効率よ〈熱エ
ネルギーに変換し、これを第２層に効率よく伝達するた
めの吸熱、蓄熱、耐熱性をもち、水平方向への熱放散全
防止するため低熱伝導率の材料からナシ、レーザー光の
波長に対応した反射防止膜の機能金もつものであること
。(3) The first layer has heat absorption, heat storage, and heat resistance to efficiently convert the energy of the laser beam into thermal energy and efficiently transmit it to the second layer, completely preventing heat dissipation in the horizontal direction. Therefore, it must not be made of a material with low thermal conductivity, but must also have an anti-reflection coating that is compatible with the wavelength of laser light.

（４）　　第３層は第２＊を機械的に保護する機能をも
たせるため強度の大きい材料であシ、第２層に吸収した
熱エネルギーが水平方向に拡散しない機能と、消去時の
応答を支配する上面からの熱放射の大きさ金相容れる機
能をもつものであること。(4) The third layer is made of a strong material in order to have the function of mechanically protecting the second layer.It also has the function of preventing the thermal energy absorbed by the second layer from spreading in the horizontal direction and of suppressing the response when erasing. The size of the heat radiation from the top surface that governs should have a function compatible with gold.

〔発明の実施例〕[Embodiments of the invention]

以下、本発明の一実施例を第１図によシ説明する。（ｂ
）図の１０は１．２〜１．５　ｍ厚の補強板でプラスチ
ック製基板であシ、前記した特性と機能を有するもので
例えばポリカーボネイト、エポキシ。An embodiment of the present invention will be explained below with reference to FIG. (b
) The reinforcing plate 10 in the figure is a 1.2 to 1.5 m thick reinforcing plate made of plastic and having the characteristics and functions described above, such as polycarbonate or epoxy.

ポリメチルメタアクリレート樹脂などが用いられる。１
は吸熱層で金属ｆ３ｉ、Ｃｒなどを基板上に数ＩＱｎｍ
厚に蒸着し、レーザー光からの光エネルギーを熱エネル
ギーに変換し、次の色調記録合金層２に伝達する。ま尼
、第１層の厚みｄをレーλ ブー光の波長λに対しｎｄ＝ｉなるように設計すれば反
射防止膜としての機能を果すことができ、変換効率が向
上する（ここでｎ：屈折率）。材質としてＧｅ、Ｓｉ、
ＳｉＣなど半導体材料を用いることか可能であシ、ポリ
イミドアミドなどの耐熱樹脂を用いてもよい。色調記録
合金層２は例えばＡｇ−４０１Ｚｎｔ−第１層上に約５
９ｎｍの厚みに蒸着したもので、レーザー光が基板１０
側から照射される（第２図参照）。この光エネルギーは
第１，２層で熱エネルギーに変換されるが、記録層２の
表面反射率が５０壬と大きいため、特に本Ａｇ　　４０
Ｚｎ合金色調記録に関しては第１層での熱吸収機能と反
射防止機能が重要である。このようにして加熱されたＡ
ｇ−Ｚｎ記録合金は第１図（ａ）に示すように、例えば
３００Ｃの加熱を加えると曲線人のように反射率を示し
、３００１：’→１５０Ｃの加熱プロセスでは曲線Ｂの
ような反射率を呈する。これはＡｇ−ｚｎ合金の体心立
方晶と大方稠密晶との相変態に基因して生じる現象であ
シ、極めて安定、再現性がよい。３はポリイミドアミド
の耐熱樹脂を数μｍ厚にスピンコードした層で記録層２
の表面を機械的に保護する。水平方向への熱拡散を防止
するため熱拡散率の小さいものが望ましい。耐熱性重視
の観点から、アルミナやガラスをスパッタリングしても
よいが、熱膨脹差による応力に耐えた膜厚を十分に薄く
する配慮が必要である。いずれにしても書込時に３００
０と室温との間でヒートサイクル上受けるので各層の熱
膨脹を近くし、膜厚を薄くする等して耐久性を上げる工
夫を行う。Polymethyl methacrylate resin or the like is used. 1
is an endothermic layer with metal f3i, Cr, etc. on the substrate with a thickness of several IQnm.
The optical energy from the laser beam is converted into thermal energy and transmitted to the next tone recording alloy layer 2. However, if the thickness d of the first layer is designed so that nd=i for the wavelength λ of the light, it can function as an antireflection film and improve the conversion efficiency (where n: refractive index). Ge, Si,
It is possible to use a semiconductor material such as SiC, or a heat-resistant resin such as polyimide amide. The tone recording alloy layer 2 is, for example, Ag-401Znt - on the first layer about 5
It was deposited to a thickness of 9 nm, and the laser beam was applied to the substrate 10.
It is irradiated from the side (see Figure 2). This light energy is converted into thermal energy in the first and second layers, but since the surface reflectance of the recording layer 2 is as high as 50 mm, this is especially true for Ag 40.
Regarding Zn alloy color tone recording, the heat absorption function and antireflection function of the first layer are important. A heated in this way
As shown in Figure 1(a), the g-Zn recording alloy shows a reflectance like a curved line when heated to 300C, and a reflectance like a curve B when heated at 3001:'→150C. exhibits. This is a phenomenon caused by the phase transformation between the body-centered cubic crystal and the mostly dense crystal of the Ag-zn alloy, and is extremely stable and reproducible. 3 is a layer made of polyimide amide heat-resistant resin and spin-coded to a thickness of several micrometers, and is the recording layer 2.
Mechanically protect the surface of In order to prevent heat diffusion in the horizontal direction, a material with a low thermal diffusivity is desirable. From the viewpoint of emphasizing heat resistance, alumina or glass may be sputtered, but consideration must be given to making the film sufficiently thin to withstand stress due to differential thermal expansion. In any case, 300 when writing
Since the material undergoes a heat cycle between zero and room temperature, efforts are made to increase durability by making the thermal expansion of each layer similar and making the film thinner.

〔発明の効果〕〔Effect of the invention〕

本発明によれば （１）人畜無害の材料Ａｇ−Ｚｎ合金を用いて書込み消
去型光記録ディスクを製作できる。According to the present invention, (1) a writable and erasable optical recording disk can be manufactured using Ag-Zn alloy, a material that is harmless to humans and animals;

（２）本構造の多層膜構成により、書込パワーの有効利
用と書込温度の低減を図ることができる。(2) The multilayer film configuration of this structure allows effective use of write power and reduction of write temperature.

［Ｆ］）　基板材料としてガラスなどに比べ廉価なグラ
スチックを用い、膜生成プロセスも天童生産が可能なプ
ロセスを採用できるので経済的でおる。[F]) It is economical because glass, which is cheaper than glass, is used as the substrate material, and a process that allows Tendo production can be adopted for the film formation process.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は、本発明の詳細な説明図であシ、第２図は、元
ディスクの構成原理である。−１・・・第１層：吸熱、
蓄熱層、２・・・第２層二色調記録合金層、３・・・第
３層：保護膜層、１０・・・プラスチック基板。 第　１　図 （スジ ３４５　ム　７８　ｑ ３良長（×１０σｎ７１１） （ｂ）FIG. 1 is a detailed explanatory diagram of the present invention, and FIG. 2 is a diagram showing the principle of construction of the original disk. -1... 1st layer: endothermic,
Heat storage layer, 2... Second layer two-tone recording alloy layer, 3... Third layer: protective film layer, 10... Plastic substrate. Figure 1 (streak 345 mm 78 q 3 good length (×10σn711) (b)

Claims (1)

【特許請求の範囲】 １、加熱・冷却条件によつて色調が変化する光記録合金
を用いた光ディスクにおいて、補強機能を有するプラス
チック板の上に、吸熱または蓄熱機能を有する第１の層
を設け、この上に上記色調記録機能を有する第２の層を
設け、これを保護する第３層を設けた色調記録合金光デ
ィスク。 ２、第１項記載のディスクにおいて、第１の層が反射防
止機能を有する色調記録合金光ディスク。 ３、第１項記載のディスクにおいて、プラスチック基板
は入熱源であるレーザの光波長に対し透明であり、かつ
、第１層に吸熱または蓄熱された熱の放射を防ぐため、
第２層の記録合金層に比べて低熱伝導率の材料からなる
色調記録合金光ディスク。 ４、第１項記載のディスクにおいて、第３層が第２層の
水平方向の熱拡散を防ぐため熱伝達率の低い材料からな
る色調記録合金光ディスク。 ５、第１項記載のディスクにおいて、プラスチック基板
と第３層（保護膜）の熱膨脹が、第１層（吸、蓄熱層）
および第２層（記録合金層）に比べて同等かまたは大き
い色調記録合金光ディスク[Claims] 1. In an optical disk using an optical recording alloy whose color tone changes depending on heating and cooling conditions, a first layer having a heat absorption or heat storage function is provided on a plastic plate having a reinforcing function. A color tone recording alloy optical disc, comprising a second layer having the color tone recording function as described above, and a third layer protecting the second layer. 2. A tone recording alloy optical disc according to item 1, wherein the first layer has an antireflection function. 3. In the disk described in item 1, the plastic substrate is transparent to the optical wavelength of the laser that is the heat input source, and in order to prevent radiation of heat absorbed or stored in the first layer,
A color recording alloy optical disc made of a material having a lower thermal conductivity than a second recording alloy layer. 4. A tone recording alloy optical disk according to item 1, in which the third layer is made of a material with a low heat transfer coefficient to prevent horizontal heat diffusion of the second layer. 5. In the disk described in item 1, the thermal expansion of the plastic substrate and the third layer (protective film) causes the thermal expansion of the first layer (heat absorption and heat storage layer).
and a recording alloy optical disc with the same or larger color tone than the second layer (recording alloy layer)