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JPH05298748A - Optical information recording medium and designing method for structure thereof - Google Patents

Optical information recording medium and designing method for structure thereof

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Publication number
JPH05298748A
JPH05298748A JP9760792A JP9760792A JPH05298748A JP H05298748 A JPH05298748 A JP H05298748A JP 9760792 A JP9760792 A JP 9760792A JP 9760792 A JP9760792 A JP 9760792A JP H05298748 A JPH05298748 A JP H05298748A
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layer
recording
state
crystalline
cry
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JP3012734B2 (en )
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Nobuo Akahira
Shigeaki Furukawa
Kenichi Nishiuchi
Eiji Ono
Kenichi Osada
Noboru Yamada
惠昭 古川
鋭二 大野
昇 山田
健一 西内
信夫 赤平
憲一 長田
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Matsushita Electric Ind Co Ltd
松下電器産業株式会社
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Abstract

PURPOSE: To provide an optical information recording medium which has high CN ratio, high erasing rate and which is overwritable by a single laser beam with a wide erasing power allowance width and a method for designing it.
CONSTITUTION: A dielectric layer 7, a recording layer 8, a dielectric layer 9 are sequentially laminated on a board 6, and two film surfaces are laminated on the inside through an adhesive layer 10. The layer 8 is formed of substance in which a reversible phase change occurs between an amorphous phase and a crystalline phase. When the layer 8 is in an amorphous state or a crystalline state, a difference of ΔT0 of optical transmittance T0 (amo) and T0 (cry) under a condition held by dielectric materials is selected to 20% or less, and the thickness is optically calculated by varying thicknesses of the layers 7, 9. Reflectivities of the recording layer 8 from an absorption factor recording medium with an emitted laser light ray 11 having a wavelength λ are A (amo), R (amo) in the amorphous state of the recording layer 8 and A (cry), R (cry) in the crystalline state, and the thickness simultaneously satisfies two conditions of a difference ΔA≥5% of the absorption factors and a difference ΔR ≥15% of the reflectivities between the two states.
COPYRIGHT: (C)1993,JPO&Japio

Description

【発明の詳細な説明】 DETAILED DESCRIPTION OF THE INVENTION

【0001】 [0001]

【産業上の利用分野】本発明は、基板上に形成された相変化材料薄膜にレ−ザ−ビーム等の高エネルギービームを照射することにより信号品質の高い情報信号をオーバライトすることのできる書換え可能な光学的情報記録媒体の構成およびその構成方法に関する。 The present invention relates is a phase change material thin film formed on a substrate - capable of overwriting with a high signal quality information signal by irradiating a high energy beam such as a beam - The configuration and its configuration method rewritable optical information recording medium.

【0002】 [0002]

【従来の技術】基板上に形成したカルコゲナイド薄膜にレーザ光線を照射して局所的な加熱を行い、微小部分の光学的な特性(屈折率)を変化させることができることは光誘引性の相変化現象として既に知られている。 Perform local heating by irradiating a laser beam to the Prior Art chalcogenide thin film formed on a substrate, the phase change optical attractiveness that can change the optical properties of the minute portion (refractive index) It is already known as a phenomenon. 即ち、レーザ光線の照射条件を選べば照射部を原子結合状態が比較的乱れた状態(アモルファス相)から比較的整った状態(結晶相)、また反対に結晶相からアモルファス相へと高速に相変化させることが可能であり、高密度情報記録を行う方法の一つとして応用開発が行われてきた。 That is, the state in which the irradiation unit be selected irradiation conditions of the laser beam atomic bonding state is relatively well equipped from a relatively disordered state (amorphous phase) (crystalline phase), also a phase at high speed from the crystalline phase to the opposite to the amorphous phase it is possible to vary, is applied developed as a method for performing high-density information recording has been performed.

【0003】相変化記録のメリットの1つは、記録手段として単一のレーザビームのみを用い、情報信号をオーバライトできる点にある。 [0003] One of the advantages of phase change recording uses only a single laser beam as a recording unit, in that the information signal can be overwritten. すなわち、レーザー出力を記録レベルと消去レベルの2レベル間で情報信号に応じて変調し記録済みの情報トラック上に照射すると、既存の情報信号を消去しつつ新しい信号を記録することが可能である(特開昭56−145530号公報)。 That is irradiated onto modulates recorded information track in accordance with the information signal between two levels of the laser power recording level and erasure level, it is possible to record a new signal while erasing the existing information signal (JP-A-56-145530 JP). この方法は光磁気記録のように磁気回路部品が不要なことからヘッドが簡素化できる点、消去動作を必要としないため書換え時間を短縮することできる点が映像や音声信号の記録に有利と考えられ記録媒体の開発研究が進められている。 The method considered to be advantageous to the recording of the magneto-optical recording magnetic circuit components that can head simplified since unnecessary, the video and audio signals that can be to shorten the rewrite time because it does not require an erase operation as development of is recording medium has been developed.

【0004】オーバライトに特有の課題についても抽出が行われ、その解決策の提案がなされてきている。 [0004] also extracted for specific to overwrite task is carried out, it has been made proposals of their solutions. 例えばオーバライト時の消去率が消去動作のみを行った場合の消去率に比べて低くなるという課題があった。 For example the erasure rate during overwriting is a problem that is lower than the erase ratio in the case of performing only the erase operation. この課題に対して我々は特開平1−149238号公報において、アモルファス状態である記録マーク部における光吸収率と結晶状態である未記録部における光吸収率を同等にした記録媒体、及び結晶状態部での光吸収率をアモルファス状態部での光吸収率よりも大きくした記録媒体を提案した。 In our Japanese Patent Laid-Open 1-149238 discloses for this problem, the recording medium equal to the light absorption rate in the non-recorded portion is a crystalline state and optical absorptance of the recording mark portion in an amorphous state, and crystalline state portion the light absorption rate in the proposed recording medium is larger than the light absorption rate in the amorphous state portion. 即ち、図5に示すように表面の平滑な基板1 That is, smooth the surface of the substrate as shown in FIG. 5 1
の上に誘電体3でサンドイッチした記録層2を形成した媒体、及び誘電体3の上にさらに光反射層4を設け、保護板5を付けた構成の媒体において、主として誘電体層各層の厚さを適当に選ぶことで上記光吸収率に関する条件を満足する光記録媒体を形成し、この媒体ではオーバライト時の消去率が改善されることを開示した。 Medium to form a recording layer 2 which is sandwiched by the dielectric 3 on top of, and more light-reflective layer 4 on the dielectric 3 is provided, in the medium having the structure with a protective plate 5, mainly the dielectric layer thickness of each layer of the form an optical recording medium which satisfies the conditions relating to the light absorption rate in appropriately choosing it, in this medium is disclosed that erasure rate during overwriting may be improved.

【0005】しかしながら、この従来例の実施例の媒体の場合には反射率変化が十分大きいとは言えなかった。 However, reflectivity changes in the case of the medium of the embodiment of this conventional example can not be said to be sufficiently large.
例えば3頁の実施例第2表において、アモルファス状態の吸収率が結晶状態の吸収よりも大きな媒体No. For example, in Example Table 2, page 3, larger media than the absorption rate of absorption of the amorphous state is a crystalline state No. 1、 1,
No. No. 4が19.1%、16.4%という反射率変化を示すのに対して、結晶状態の方がアモルファス状態よりも吸収率の大きい媒体No. 4 is 19.1%, whereas showing reflectance variation of 16.4%, a large media absorptivity than the amorphous state towards the crystalline state No. 3、No. 3, No. 6は9.7%、 6 is 9.7%,
11.2%と小さな反射率変化しか示さなかった。 11.2% and a small change in reflectance only did not. 特に記録膜が40nmの場合には半分以下の値しか示していない。 Especially when the recording film is 40nm only it shows less than half of the value. 図6は、特開平1−149238号公報中に記載の実施例の結果をグラフ化したものであって、結晶部での光吸収率をA(cry)、アモルファス部での光吸収率をA(amo)とし、記録前後の2つの状態における光吸収率の差ΔA(=A(cry)−A(amo))とC/Nならびに消去率の関係を示したものである。 Figure 6 is a a graph of the results of Examples described in JP-A-1-149238, the light absorption rate in the crystalline part A (cry), the light absorption rate in the amorphous portion A and (amo), it shows the relationship between the two light absorption rate in the state of the difference ΔA (= a (cry) -A (amo)) and C / N and erase ratio of before and after recording. これによれば光吸収率の差ΔAが正方向に増加するに従って消去率が改善されていること、一方C/Nはわずかづつではあるが低下していることが分かる。 According to this the erasure rate is improved according to the difference ΔA of the light absorption factor increases in the positive direction, it can be seen that there has been reduced in the meantime C / N HawazuKazutsu. この場合のC/N低下の原因は、図7によって明らかである。 Cause of C / N drop in this case is apparent from FIG.

【0006】図7は、図6と同じく特開平1−1492 [0006] FIG. 7, like JP-as in FIG. 6 1-1492
38号公報中に記載の実施例の結果をグラフ化したものであって、結晶部での光吸収率をA(cry)、反射率をR A a graph of the results of Examples described in 38 discloses a light absorption rate in the crystalline part A (cry), the reflectance R
(cry)、アモルファス部での光吸収率をA(amo)、反射率をR(amo)とし、記録前後の2つの状態における光吸収率の差ΔA(=A(cry)−A(amo))と反射率変化量ΔR (Cry), the light absorption rate in the amorphous portion A (amo), the reflectance and R (amo), the difference in the light absorption rate in the two states before and after recording ΔA (= A (cry) -A (amo) ) and the reflectance change amount ΔR
(=R(cry)−R(amo))の関係を示したものである。 It shows the relationship between (= R (cry) -R (amo)). これによれば、従来例の記録媒体では光吸収率の差ΔAが増加するにしたがって反射率変化量ΔRは一方向的に減少しており、オーバライト時の消去率と信号振幅とは相反する関係にあったことが分かる。 According to this, reflectance change amount ΔR according to the difference ΔA of the light absorption rate is increased in the recording medium of the prior art are reduced unidirectionally, contrary to the erase ratio and the signal amplitude at the time of overwrite it can be seen that there was a relationship.

【0007】別の従来例としては特開平3−11384 [0007] Another Patent as prior art 3-11384
4号公報は反射層を用いない媒体構造で、かつ記録膜が80nmと厚い構成の媒体を開示している(3ページ第1表)。 4 No. in media construction without a reflective layer, and the recording film discloses a medium 80nm and thicker structure (3 pages Table 1). この場合は、しかしながら、この場合には結晶部の光吸収率がアモルファス部の吸収率に比べて十分大きいできる媒体条件が開示されていない。 In this case, however, the medium conditions that can sufficiently larger than the light absorption rate of the crystal portion in the absorption rate of the amorphous portion in this case is not disclosed. 例えば、アモルファス部の吸収率が結晶部よりも10%以上大きい構成の開示はあるが、結晶部の吸収率がアモルファス部より大きい媒体では、その差は高々2.1%であり、融解潜熱の差をキャンセルするには不十分であった。 For example, although the absorption of the amorphous portion is disclosed in greater structure by 10% or more than the crystal unit, a medium absorption rate is greater than the amorphous portion of the crystal portion, the difference is at most 2.1%, the latent heat of fusion It was insufficient to cancel the difference.

【0008】 [0008]

【発明が解決しようとする課題】アモルファス状態である記録マーク部と結晶状態である非記録マーク部の両部における光吸収率差ΔAに留意した上記従来例(特開平1−149238号公報)に開示された記録媒体ではオーバライトモード記録における消去率の向上が実現されたが、その一方では図7に示されたように、記録前後の反射率変化量ΔRが小さくなっていた。 In the conventional example noted light absorptivity difference ΔA in both parts of the non-recording mark portion which is a recording mark portion crystalline state is an amorphous state [0006] (JP-A-1-149238) Although improvement in erasing ratio at overwriting mode recording is disclosed a recording medium is achieved, on the other hand, as shown in FIG. 7, reflectance change amount ΔR before and after recording was smaller. 反射率変化量Δ Reflectance change amount Δ
Rは信号の大きさそのものであるから、基本的にはΔR Since R is the signal magnitude itself is basically ΔR
が小さくなればC/Nも低下する。 The C / N is also reduced if smaller. この時、従来例の場合のように、記録マークピッチが2μm以上(線速度1 At this time, as in the conventional example, the recording mark pitch is 2μm or more (linear speed 1
5m/s,記録周波数7MHzから計算可能)といった記録条件では、形成される記録マーク部の面積はレーザスポットに比較して十分大きくなるから、ΔRが多少小さくても全体として大きな反射光量の変化が生じ大きなC/Nが得られるが、マークピッチをもっと詰めて記録密度を高めようという場合には同様ではない。 5 m / s, the recording conditions, such as computable) from the recording frequency 7 MHz, since the area of ​​the recording mark portion formed is sufficiently larger than the laser spot, a large change in reflected light as a whole ΔR is also slightly smaller large C / N occurs is obtained, but not the same as in the case of trying to increase the recording density by more packed mark pitch. この場合には、記録マークの大きさがレーザスポットの大きさと同等およびそれ以下に小さくなるからΔRが小さければ、それだけ小さな反射光量変化しか得られなくなり、 In this case, if ΔR is smaller because the size of the recording mark becomes small magnitude equal and below and of the laser spot, can not be obtained only much smaller amount of reflected light changes,
ΔR低下の影響がもろにC/Nの大きな低下となって現れる。 Effect of ΔR decrease appears as a large decrease in all the way C / N. 即ち、高密度記録を行うという前提ではオーバライト時におけるC/Nと消去率とを同時に満足できる記録媒体は未だ実現されていなかったと言える。 That is, it can be said that a high density recording medium capable of satisfying the C / N and erase ratio at overwriting simultaneously assuming that the recording performing has not been realized yet.

【0009】別の課題としては、従来相変化記録媒体に用いられてきたマーク位置記録(あるいはPPM記録) [0009] As another problem, the conventional phase change recording medium mark position recording that has been used (or PPM recording)
方式をマークエッジ記録(あるいはPWM記録)方式に置き換えるためにはより高い消去率が必要になるということである。 Method is that require a higher erasure rate is to replace the mark edge recording (or PWM recording) scheme. マーク位置記録では記録マークの形状が多少歪んでいてもピーク位置さえ検出できればエラーにならないが、マーク位置記録では形状の歪がそのままエラーになる。 Although not an error if detected even peak position be distorted somewhat the shape of a recording mark in the mark position recording, it becomes an error distortion shape in mark position recording. この場合には例えば磁気記録の場合と同様、 As with the case of the example magnetic recording in this case,
26dB程度の消去率をクリアーする必要がある。 It is necessary to clear the erasure rate of about 26dB.

【0010】本発明の目的は、記録マーク長がレーザスポットの大きさに近い高密度信号のオーバライト記録を行っても、C/N及び消去率がともに大きいこと、あるいはマークエッジ記録に適合する大きな消去率が得られることを目指し、上記ΔA,ΔRがいずれも十分大きな記録媒体を提供するものである。 An object of the present invention, even if the overwrite recording high-density signals near the recording mark length is the size of the laser spot, conforms to C / N and erase ratio are both large or mark edge recording aim a large erasure rate is obtained, but the .DELTA.A, [Delta] R is to provide a large recording medium both sufficient. また本発明のもう1つの目的は上記記録媒体を構成する方法を提供するものである。 Further another object of the present invention is to provide a method for forming the recording medium.

【0011】 [0011]

【課題を解決するための手段】本発明は基板上に少なくとも第1の誘電体薄膜層、波長λのレーザ光線を照射することにより可逆的構造変化を生じ、光学定数(屈折率n、消衰係数k)が相対的に大である結晶状態と相対的に小であるアモルファス状態との間で光学的特性を可逆的に変化する相変化物質薄膜からなる記録層および第2 The present invention SUMMARY OF THE INVENTION At least the first dielectric thin film layer on a substrate results in a reversible structural change by irradiation with a laser beam of wavelength lambda, the optical constants (refractive index n, extinction coefficient k) is the optical properties reversibly changing the phase change material thin film between the amorphous state is relatively small and the crystalline state is a relatively large recording layer and the second
の誘電体薄膜層を順次積層してなる光学的情報記録媒体において、記録前後での反射率差および吸収率差の和よりも記録前後の透過率変化量が等しいか大きくなるように記録膜の厚さを選ぶ。 Of the optical information recording medium of the dielectric thin film layers formed by sequentially stacking, recording of the recording film as the transmittance variation before and after the recording or greater than or equal to the sum of the reflectance difference and the absorption index difference before and after choose the thickness.

【0012】この場合の透過率変化量は上記記録膜が上記誘電体材料で挟まれた条件下(即ち、誘電体材料から記録材料に入射し、記録材料中を通過して、反対側の誘電体材料中に出射する条件)での光透過率T0(amo)とT [0012] transmittance variation in this case the conditions above recording film is sandwiched by the dielectric material (i.e., is incident on the recording material from the dielectric material, and passes through the recording material, opposite the dielectric light transmittance at the condition) that emits the body material T0 (amo) and T
0(cry)の差、ΔT0(=T0(amo)−T0(cry))で定義し、反射率変化量15%以上、吸収率差5%以上を実現するためにはΔT0=20%となる膜厚よりも薄く選ぶことが必要である。 Difference 0 (cry), defined ΔT0 (= T0 (amo) -T0 (cry)), reflectance change amount of 15% or more, the .DELTA.T0 = 20% in order to achieve a 5% or more absorptivity difference it is necessary to select thinner than the film thickness. さらに、その上で上記第1および第2の誘電体薄膜層の厚さd1,d2をそれぞれ独立に様々に仮定して、マトリクス法により上記記録膜がアモルファス状態にある場合、結晶状態にある場合の反射率、 Furthermore, thereon with variously assume independently thicknesses d1, d2 of the first and second dielectric thin film layer, if the matrix method the recording layer is in the amorphous state, when in the crystalline state reflectance of,
吸収率をそれぞれ算出し、上記条件を満たす誘電体厚さd1,d2の組合せを決定する。 The absorption rate was calculated, to determine the combination of the above conditions are satisfied dielectric thickness d1, d2.

【0013】 [0013]

【作用】上記光学的情報記録媒体においては入射光Iの行方は記録層で吸収されて熱に変わる部分(A)、媒体から反射される部分(R)、媒体を通過してしまう部分(T)の3つに分けることができる。 [Action] parts in the optical information recording medium whereabouts of the incident light I is change to be absorbed by the recording layer when heat (A), the portion which is reflected from the medium (R), will pass through the medium portion (T ) of can be divided into three. ここで記録層に吸収される光は記録層がアモルファス状態である時と結晶状態である時とで異なり、各々A(amo)=I−[R(amo) Here light that is absorbed in the recording layer is different between when a crystalline state and when the recording layer is in the amorphous state, respectively A (amo) = I- [R (amo)
+T(amo)]、A(cry)=I−[R(cry)+T(cry)]となる。 + T (amo)], the A (cry) = I- [R (cry) + T (cry)]. つまりアモルファス部と結晶部の間の光吸収率差は、ΔA==A(cry)−A(amo)=[R(amo)−R(cry)] Light absorptance difference between words and the amorphous portion crystal part, ΔA == A (cry) -A (amo) = [R (amo) -R (cry)]
+[T(amo)−T(cry)]、即ちΔT=T(amo)−T(cry) + [T (amo) -T (cry)], i.e. ΔT = T (amo) -T (cry)
とおいてΔA=ΔT1−ΔRと表わされる。 It is expressed as ΔA = ΔT1-ΔR at the. 本願の場合には記録膜は誘電体材料で挟まれているので上記ΔTは上記ΔT0として考える。 Since the present case the recording film is sandwiched by dielectric material above ΔT is considered as the .DELTA.T0.

【0014】記録層が厚くなりすぎると記録層の状態に関係なく入射光の大部分は記録層に吸収されるか媒体表面で反射されてしまうことになる。 [0014] Most of the incident light regardless of the state of the recording layer becomes too thick recording layer would become reflected in either the medium surface is absorbed in the recording layer. つまり、上式ΔA= In other words, the above equation ΔA =
Δ−ΔRの右辺第1項は零に近づく。 The first term on the right side of the delta-[Delta] R approaches zero. 即ちΔA≒−ΔR That ΔA ≒ -ΔR
(<0)となり、本願の目的は達成できない。 (<0), and the object of the present can not be achieved. 従って、 Therefore,
吸収率差ΔAならびに反射率変化を十分大きく、例えばΔA≧5%かつΔR≧15%を確保しようとすれば、透過率差ΔT0を20%以上確保することが必要条件である。 Absorptivity difference .DELTA.A and sufficiently large reflectance change, for example if an attempt ensure .DELTA.A ≧ 5% and [Delta] R ≧ 15%, it is a necessary condition to ensure the transmittance difference ΔT0 20% or more. この条件下で初めて、ΔR≧15%かつΔA≧5% For the first time in this condition, ΔR ≧ 15% and ΔA ≧ 5%
を満たす第1の誘電体層、第2の誘電体層の膜厚を選ぶことが可能となる。 The first dielectric layer satisfying, it is possible to choose the thickness of the second dielectric layer.

【0015】 [0015]

【実施例】本発明の代表的な光学情報記録媒体は、図1 EXAMPLES representative optical information recording medium of the present invention, FIG. 1
に示すように基板6の上に第1の誘電体層7、波長λのレーザ光線の照射により上記波長λでの光学定数(屈折率n、消衰係数k)が相対的に大である結晶状態と相対的に小であるアモルファス状態との間で光学的特性を可逆的に変化する相変化材料薄膜からなる記録層8、第2 Crystal optical constants of the above wavelength lambda (refractive index n, extinction coefficient k) is relatively large by the irradiation of the first dielectric layer 7, the laser beam of wavelength lambda on the substrate 6 as shown in recording layer 8 of the optical properties between the amorphous state is a state relatively small reversibly changing phase change material thin film, the second
の誘電体層9を順次積層して形成し、基板側から記録再生のためのレーザ光線11を入射させるものである。 Dielectric layer 9 sequentially formed stacked, it is intended to be incident laser beam 11 for recording and reproduction from the substrate side. 図1ではホットメルトタイプの接着層10を介して上下対称になるように2枚が張り合わせた構成になっているが、図2のように第2の誘電体の上にUV樹脂等の保護層12を形成した単板構造も可能である。 Although two so as to be vertically symmetrical with an adhesive layer 10 in FIG. 1, the hot-melt type has a configuration in which laminated, protective layer such as a UV resin on the second dielectric as shown in Fig. 2 veneer structure formed of 12 are possible. また、図3のように基板上に第2の誘電体層8、記録層7、第1の誘電体層6を順に積層し膜面がむきだしの状態または保護層12を通じてレーザ光線を照射することも当然可能である。 The second dielectric layer 8 on the substrate as shown in FIG. 3, the recording layer 7, the film surface by laminating the first dielectric layer 6 in order to irradiate the laser beam through the state or the protective layer 12 of the bare it is of course also possible. この場合の保護層12は対摩耗性等の強度が要求され、ダイアモンドライクカーボン膜、BN膜、TiN The protective layer 12 in this case is the intensity of such wear resistance is required, diamond-like carbon film, BN film, TiN
膜等を用いる。 Use of the film, or the like.

【0016】基板6に用いる材料としては通常光ディスク等に用いられているPMMA、ポリカーボネイト、アモルファスポリオレフィン等の透明樹脂、Al,Cu等の金属やこれらをベースにした合金、ガラス等を用いる。 [0016] PMMA as a material used for the substrate 6 used in the normal optical disk or the like, using polycarbonate, a transparent resin such as amorphous polyolefin, Al, based alloy metals and these Cu, or glass. 不透明板を用いる場合には基板側からの光入射ができないので、図3の構成に準じる。 Can not have the light incident from the substrate side in the case of using an opaque plate conforms to the configuration of FIG. また、光ディスクの用途では記録再生に用いるレーザ光線を導くために基板表面にサブミクロンサイズの幅、深さで同芯円またはスパイラル状の連続溝、あるいはピット列が凹凸を備えるのが通常である。 Further, there is a normal be provided with the width of the sub-micron size on the substrate surface for guiding the laser beam, a concentric circle or spiral continuous groove in depth, or pit sequence is an uneven used for recording and reproduction in applications of the optical disc .

【0017】上下2層の誘電体層7,9は樹脂の基板を用いる場合に基板6の表面の熱ダメージを抑える、記録時に相変化材料層が変形したり蒸発したりすることを抑える等の働きをなすものであって、樹脂、記録膜材料と比較して融点の高いこと、記録再生に用いるレーザ光線に対して透明であること、硬度が大きくて傷がつきにくいこと等の性質を有することが必要である。 The upper and lower layers of the dielectric layers 7 and 9 minimize thermal damage on the surface of the substrate 6 in the case of using a substrate resin, the phase change material layer during recording, such as suppressing or to or evaporated deformed be those which form a work, having a resin, higher melting point as compared with the recording film material, it is transparent to the laser beam used for recording and reproduction, the properties such that the scratch-resistant large hardness it is required. 例えば、S For example, S
iO 2 ,ZrO 2 、TiO 2 ,Ta 25等の酸化物、B iO 2, ZrO 2, TiO 2 , Ta oxides such as 2 O 5, B
N、Si 34 ,AlN,TiN等の窒化物、ZnS,P N, Si 3 N 4, AlN , nitride such as TiN, ZnS, P
bS等の硫化物、SiC等の炭化物、CaF 2等のフッ化物、ZnSe等のセレン化物及びこれらの混合物としてZnS−SiO 2 、SiNO等、あるいはダイヤモンド薄膜、ダイヤモンドライクカーボン等を用いることができる。 sulfides such as bS, carbides such as SiC, fluorides such as CaF 2, can be used selenides ZnSe, etc., and ZnS-SiO 2, SiNO such as a mixture thereof, or a diamond thin film, a diamond-like carbon.

【0018】本発明で記録層8に用いる物質薄膜は、相変化物質薄膜の中でもレーザ光線の照射でアモルファス−結晶間の可逆的相変態を生じるものであって、結晶状態ではアモルファス状態よりも大きな屈折率、消衰係数を示すものを用いる場合に最も有効的である。 The material thin film used for the recording layer 8 in the present invention, amorphous irradiation of the laser beam among the phase change material thin film - be those in which a reversible phase change between crystal, larger than the amorphous state in the crystalline state refractive index, it is most effective when used indicates the extinction coefficient. 代表的にはGe−Sb−Te,Ge−Te,In−Sb−Te, Typically Ge-Sb-Te, Ge-Te, In-Sb-Te,
Sb−Te,Ge−Sb−Te−Pd,Ag−Sb−I Sb-Te, Ge-Sb-Te-Pd, Ag-Sb-I
n−Te,Ge−Bi−Sb−Te,Ge−Bi−T n-Te, Ge-Bi-Sb-Te, Ge-Bi-T
e,Ge−Sn−Te、Ge−Sb−Te−Se,Ge e, Ge-Sn-Te, Ge-Sb-Te-Se, Ge
−Bi−Te−Se、Ge−Te−Sn−Au等の系、 -Bi-Te-Se, Ge-Te-Sn-Au, etc. of the system,
あるいはこれらの系に酸素、窒素、遷移金属等の添加物を加えた系を用いることができる。 Or can be used oxygen in these systems, nitrogen, additives a system plus the like transition metals. これらの薄膜は通常成膜された時はアモルファス状態であるが、レーザ光線等のエネルギーを吸収して結晶化し光学的濃度が高くなる。 These films are amorphous state when normally deposited, the optical density was crystallized by absorbing energy such as a laser beam is increased. 実際に記録媒体として用いる場合には記録膜面の全体を予め結晶化しておき、レーザ光線を細く絞って照射し、照射部をアモルファス化して光学定数を変化させる。 Advance crystallize the entire recording film surface in the case of using as an actual recording medium, by irradiating a laser beam narrow squeezed, to change the optical constants and amorphous irradiation unit. 上記変化は、上記記録膜にさらに変化を与えない程度に弱くしたレーザ光線を照射し、反射光の強度変化、 The change irradiates a laser beam that is weak enough not give more change in the recording film, the intensity change of the reflected light,
透過光の強度変化を検出して情報を再生する。 By detecting changes in the intensity of the transmitted light to reproduce information. 記録層の厚さは記録再生に用いるレーザ光線の波長に依存し、記録層がアモルファス状態および結晶状態にある時に上記誘電体材料で挟まれた条件下での光透過率T0(am The thickness of the recording layer depends on the wavelength of the laser beam used for recording and reproduction, the light transmittance under conditions where the recording layer is sandwiched by the dielectric material when in the amorphous and crystalline states T0 (am
o)とT0(cry)の差、ΔT0(=T0(amo) o) and T0 (the difference between the cry), ΔT0 (= T0 (amo)
−T0(cry))が20%となる厚さよりも薄く選ぶ。 -T0 (cry)) is chosen smaller than the thickness of the 20%.

【0019】本願において最も好ましい特性を有する記録材料はGeTe−Sb 2 Te 3擬2元系材料の内でもG The recording material having the most desirable properties in the present application G Among GeTe-Sb 2 Te 3 pseudo binary system material
eTeの割合が67〜33モル%の組成、とりわけGe The composition ratio of eTe is 67 to 33 mol%, especially Ge
2 Sb 2 Te 5 ,GeSb 2 Te 4 ,GeSb 4 Te 7の化合物組成、および上記組成にSb,Bi,Ge,Sb,C 2 Sb 2 Te 5, GeSb 2 Te 4, compound composition of GeSb 4 Te 7, and the above composition Sb, Bi, Ge, Sb, C
o,Pd等の添加を行った系である。 o, it is a system which was the addition of Pd, and the like. 図4は代表的にG Figure 4 is typically G
2 Sb 2 Te 5膜(アモルファス状態の複素屈折率= e 2 Sb 2 Te 5 film (complex refractive index of the amorphous state =
4.65+i1.5,結晶状態の複素屈折率=5.5+ 4.65 + i1.5, the crystalline state complex refractive index = 5.5 +
i4.2)が光学的に干渉を生じない程度に十分厚いZ Thick enough Z to the extent that I4.2) does not yield optically interfere
nS−SiO 2 (屈折率は2.1)に挟まれた状態での膜厚と透過率の関係を示す。 nS-SiO 2 (refractive index 2.1) shows the relationship between the film thickness and the transmittance in a state sandwiched between. この系では記録膜の厚さが45nmよりも薄い場合にΔT0≧20%となること、 The thickness of the recording film is .DELTA.T0 ≧ 20% when thinner than 45nm in this system,
25nmよりも薄い場合にΔT0≧25%となることが示された。 It has been shown to be .DELTA.T0 ≧ 25% when thinner than 25 nm.

【0020】GeSbTe系薄膜の膜厚を40nm以下と薄くした媒体構成ではアモルファス部での光吸収率の絶対値が減少することから反射膜を用いるのが常識と考えられてきていた。 [0020] In thinned medium constituting the thickness of the GeSbTe-based thin film and 40nm or less to use a reflective film from reducing the absolute value of the light absorption rate in the amorphous portion it was been considered common knowledge. 40nmや25nmの薄い記録層を用い、かつ反射層を用いずにオーバライト可能な媒体を構成した例はまだ無い。 A thin recording layer of 40nm and 25 nm, and example in which the overwritable medium without using a reflection layer is still no.

【0021】記録層の厚さを固定した上で各層の複素屈折率と膜厚からマトリクス法(例えば久保田広著「波動光学」岩波書店、1971年、第3章を参照)によって第1及び第2の誘電体の膜厚を計算した。 The complex refractive index of each layer, fix the thickness of the recording layer and the matrix method from the film thickness (e.g., Hiroshi Kubota et al., "Wave Optics", Iwanami Shoten, 1971, Chapter 3) first and by the thickness of the second dielectric was calculated. 具体的には、 In particular,
各層を構成する物質の光学定数(屈折率、消衰係数)を求め、各層の膜厚を仮定して表面を含む全ての界面に対してエネルギー保存則に基づき光エネルギーの収支を計算する。 Optical constants (refractive index, extinction coefficient) of the material constituting each layer sought to calculate the balance on the basis of light energy on the energy conservation law for all interfaces including the surface assuming a film thickness of each layer. 即ち、多層媒体での各界面についてこのエネルギー収支の方程式をたて、得られた連立方程式を解くことで、入射光に対する透過光の強度、反射光の強度ならびに各層での吸収量を求めることができる。 That is, vertical equation of the energy balance for each interface in the multilayer medium, by solving the resulting system of equations, the intensity of the transmitted light to incident light, is possible to determine the absorption in the intensity of the reflected light and the layers it can. 記録膜が結晶状態にある時とアモルファス状態にある時のいずれの場合についても上記計算を行うことにより、記録前後の反射率変化量、吸収差を知ることができる。 By performing the above calculations for each case recording film when in the amorphous state when in a crystalline state, it is possible to know reflectance change amount before and after recording, the absorption difference. 2つの状態間での反射率の差がなるべく大きく(≧15%)、結晶状態の吸収がアモルファス状態の吸収よりも5%以上大きい膜厚条件を選ぶ。 Is as large as possible a difference in reflectance between two states (≧ 15%), the absorption of the crystalline state chooses larger thickness condition 5% or more than the absorption of the amorphous state.

【0022】本発明の書換え可能な光学的情報記録媒体は通常の光学薄膜を形成する場合と同様に真空蒸着、マグネトロンスパッタリング、DCスパッタリング、イオンビームスパッタリング、イオンプレーティング等の方法で各層を順次積み重ねて行く方法で形成することができる。 The rewritable optical information recording medium of the present invention is a vacuum vapor deposition similarly to the case of forming the conventional optical thin film, magnetron sputtering, DC sputtering, ion beam sputtering, sequentially stacked layers by a method such as ion plating it can be formed by a method go. 計算に基づき形成した媒体が設定通りにできたいるか否かは媒体の反射率、透過率をスペクトルメーターで実測することによって検証することができる。 Dolphin whether that formed was medium based on the calculation could be set as can be verified by actual reflectance of the medium, a transmittance spectrometer.

【0023】以下、具体例をもって本発明をさらに詳しく説明する。 [0023] Hereinafter, details of this invention are described with specific examples. (実施例1)1つの真空チャンバー中に直径100mm (Example 1) 100mm diameter in one vacuum chamber
ターゲットに対応する4つのカソードを備えたスパッタ装置を用い、上述の計算に基づいてレーザ波長680n Using a sputtering apparatus provided with four cathodes corresponding to the target, the laser wavelength 680n based on the above calculation
mに対応する記録媒体を5枚作成した(表1)。 It created 5 sheets of recording medium corresponding to m (Table 1). 基板の材質はポリカーボネイトで、サイズは外径300mm、 The material of the substrate is polycarbonate, size outer diameter 300 mm,
内径35mm、厚さ1.2mmとした。 Internal diameter 35 mm, and a thickness of 1.2 mm. 基板の表面はピッチ1.3μm、深さ60nm、幅0.6μmの連続溝で覆われている。 The surface of the substrate pitch 1.3 .mu.m, depth 60 nm, is covered by a continuous groove width 0.6 .mu.m. この溝のある面に以下のように誘電体膜、相変化記録膜を形成した。 The dielectric film as follows on a surface of the groove, thereby forming a phase change recording film. (表1)に掲げたように、各媒体は誘電体層の厚さ以外はほぼ同様な構成をしており、第1の誘電体層は厚さ93nmのZnS−Si As listed in Table 1, each medium has a similar construction except the thickness of the dielectric layer, ZnS-Si of the first dielectric layer has a thickness of 93nm
2 (SiO 2 :20モル%)混合物膜、記録層は厚さ3 O 2 (SiO 2: 20 mol%) mixture layer, the recording layer has a thickness 3
0nmのGe 2 Sb 2 Te 5膜である。 It is Ge 2 Sb 2 Te 5 film of 0 nm. 第2の誘電体層はZnS−SiO 2 (SiO 2 :20モル%)混合物膜であり、厚さは70nm、93nm、116nm、139n The second dielectric layer ZnS-SiO 2 (SiO 2: 20 mol%) and a mixture film, the thickness of 70 nm, 93 nm, 116 nm, 139n
m、162nmとなっていて、それぞれ吸収率差ΔAおよび反射率差ΔRの異なる媒体となっている。 m, and have a 162 nm, and has a different medium with each absorptivity difference ΔA and the reflectance difference [Delta] R. スパッタガスはいずれもアルゴンを用い、ガス圧を3mTorr Both sputtering gases used were argon, 3 mTorr gas pressure
とした。 And the. 誘電体はRFスパッタを用い、300Wのパワーで毎分10nmの堆積速度で成膜した。 Dielectrics using an RF sputtering, was formed at a deposition rate per minute 10nm in power of 300 W. また記録層にはDCスパッタを用い、100Wのパワーで毎分10n The use of a DC sputtering on the recording layer, every minute 10n at the power of 100W
mの速度で成膜を行った。 The deposition was carried out at a rate of m. (表1)は上記5種類の媒体について、それぞれ第2の誘電体層の厚さを変化させた場合のΔA,ΔRの計算値、スペクトロメータによる実測値を示したものである。 (Table 1) for the five media, illustrates ΔA in the case where each changing the thickness of the second dielectric layer, the calculated value of [Delta] R, the actual measurement value measured by the spectrometer. いずれの媒体においても計算値と実測値とはよく一致していてΔA≧5%、ΔR≧1 .DELTA.A ≧ 5% may not coincide with the actually measured values ​​and calculated values ​​in any of the media, [Delta] R ≧ 1
5%の条件が満足されており、確かに本発明の目的とする媒体が構成可能であることが示された。 5% of the conditions are satisfied, the medium of interest certainly present invention has been shown to be configurable. また、本願の方法によって上記条件を有する媒体の設計が容易に行えることが示された。 Further, it can be easily design a medium having the above condition is indicated by the present methods.

【0024】 [0024]

【表1】 [Table 1]

【0025】(実施例2)実施例1のディスクを各2枚用意し、膜のついた面を内側にしてホットメルト接着剤を用いて張り合わせた。 [0025] (Example 2) The disc of Example 1 were prepared two each, bonded together with a hot melt adhesive to the marked surface of the membrane on the inside. 各ディスクを毎分1800回転で回転し、最外周部(線速度27m/s)でオーバライト特性を評価した。 Rotating each disk per minute 1800 rpm for evaluating overwrite characteristics at the outermost peripheral portion (a linear velocity of 27m / s). 記録信号はマークエッジ記録を想定して17.5MH(f1)および6.5MH(f2)の単一周波数信号とし、波長680nmの半導体レーザ光線をN. Recording signal assumes a mark edge recording the single frequency signal 17.5MH (f1) and 6.5MH (f2), N. a semiconductor laser beam having a wavelength of 680nm A. A. 0.55の対物レンズを用いて記録した(デューティー50%)。 It was recorded using a 0.55 of the objective lens (50% duty). 測定手順は、まずf1を記録してCN比を測定した後、f2をオーバライトしてf1 Measurement procedure, after measuring the CN ratio is first recorded f1, by overwriting the f2 f1
成分の減衰比を測定し消去率を測定する方法によった。 Measuring the attenuation ratio of the components was by the method of measuring the erasing ratio.
(表2)はCN比が50dBに到達するピークパワー(測定限界16mW)、CN比の飽和値、消去率の最大値及び消去率が26dBを越えるバイアスパワー域を示したものである。 (Table 2) are those peaks CN ratio reaches 50dB power (measurement limit 16 mW), the saturation value of the CN ratio, the maximum value and the erasure ratio of the erase ratio showed a bias power range exceeding 26 dB.

【0026】 [0026]

【表2】 [Table 2]

【0027】(表2)から分かるように、(表1)のΔ [0027] As can be seen from Table 2, (Table 1) delta
R、ΔAは(表2)のCN比、消去率およびバイアスパワーマージンとそれぞれ強い相関性を有しており、ΔA R, .DELTA.A has a CN ratio, the erasure ratio and bias power margin and each strong correlation (Table 2), .DELTA.A
が5%に満たない場合には消去率26dBを越えるバイアスパワー領域はほとんどないことが示された。 There If less than 5% was shown that the bias power region hardly exceeds erasure rate 26 dB. これは結晶部とアモルファス部で同等の昇温を実現するためには、結晶部ではアモルファス部よりも融解潜熱に相当する分だけより大きなエネルギーを必要とするということであって、それがΔAの5%程度に相当することを示すのであろう。 This is in order to achieve a comparable Atsushi Nobori in the crystalline portion and the amorphous portion is crystalline portion is a that it requires a large energy than the amount corresponding to the latent heat of fusion than the amorphous portion, it is a ΔA it would indicate that corresponding to approximately 5%. またCN比で50dB以上を得るためにはΔRが15%以上は必要であることが示された。 In order to obtain more than 50dB in CN ratio ΔR was shown to be 15% or more is necessary.

【0028】(実施例3)実施例1、2と同様にポリカーボネイト基板、ZnS−SiO 2混合物薄膜、Ge 2 [0028] (Example 3) Similarly polycarbonate substrate as in Example 1,2, ZnS-SiO 2 mixture film, Ge 2 S
2 Te 5薄膜を用いて各種記録媒体を試作し、その特性を評価した。 with b 2 Te 5 thin film fabricated with various recording media, and their characteristics were evaluated. (表3)は680nm、780nm、83 (Table 3) is 680nm, 780nm, 83
0nmの各波長に適合するように設計試作した記録媒体についての評価結果を示す。 The evaluation results of the recording medium designed prototype to fit each wavelength 0 nm. 表中、◎印はΔR≧20% In the table, ◎ mark ΔR ≧ 20%
かつΔA≧5%を満足する膜厚条件またはΔR≧15% And the film thickness conditions or [Delta] R ≧ 15% satisfying .DELTA.A ≧ 5%
かつΔA≧10%を満足する誘電体層膜厚の条件があること、○印は同じくΔR≧15%かつΔA≧5%を満足する条件があること、×印は上記条件が満たされないことを示す。 And that there is a condition of the dielectric layer thickness which satisfies ΔA ≧ 10%, ○ mark that there are conditions that also satisfies the [Delta] R ≧ 15% and ΔA ≧ 5%, the × mark the above condition is not satisfied show.

【0029】 [0029]

【表3】 [Table 3]

【0030】(実施例4)実施例1、2と同様のことをガラス基板でも行い、同様の結果を得た。 [0030] (Example 4) carried out in a glass substrate to a same manner as in Examples 1 and 2, with similar results.

【0031】 [0031]

【発明の効果】本発明によって、大きなCN比、高い消去率ならびにその広いパワー許容幅(マージン)を有する記録媒体ならびにその設計方法が提供された。 The present invention, large CN ratio, a recording medium and a method of designing a high erasure ratio and the wider power tolerance (margin) is provided.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

【図1】本発明の光学情報記録媒体の1実施例の構成を示す図 Shows a configuration of one embodiment of an optical information recording medium of the present invention; FIG

【図2】本発明の光学情報記録媒体の1実施例の構成を示す図 Shows a configuration of one embodiment of an optical information recording medium of the present invention; FIG

【図3】本発明の光学情報記録媒体の1実施例の構成を示す図 Shows a configuration of one embodiment of an optical information recording medium of the present invention; FIG

【図4】本発明の1実施例において。 [4] In one embodiment of the present invention. 記録媒体を構成する記録層の厚さと透過率の関係を示す図 It shows the relationship between the thickness and the transmittance of the recording layer of the recording medium

【図5】従来の相変化光記録媒体の構成を示す断面図 5 is a sectional view showing the structure of a conventional phase change optical recording medium

【図6】従来例の実施例中に記載されている記録媒体の有するCN比および消去率と光吸収率差ΔAとの関係をグラフ化した図 6 is a diagram showing a graph of a relationship between the CN ratio and erasing ratio and the light absorptivity difference ΔA with the recording medium described in the examples of the prior art

【図7】従来例の実施例中に記載されている記録媒体の有する反射率変化量ΔRと光吸収率差ΔAとの関係をグラフ化した図 7 is a diagram graph of the relationship between the reflectance change amount ΔR and the light absorptance difference ΔA with the recording medium described in the examples of the prior art

【符号の説明】 DESCRIPTION OF SYMBOLS

1 基板 2 記録層 3 誘電体層 4 光反射層 5 保護板 6 基板 7 第1の誘電体層 8 記録層 9 第2の誘電体層 10 接着層 11 レーザ光線 12 保護層 1 substrate 2 recording layer 3 dielectric layer 4 the light reflecting layer 5 protective plate 6 substrate 7 first dielectric layer 8 recording layer 9 second dielectric layer 10 adhesive layer 11 the laser beam 12 protective layer

───────────────────────────────────────────────────── フロントページの続き (72)発明者 赤平 信夫 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 大野 鋭二 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 古川 惠昭 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 ────────────────────────────────────────────────── ─── of the front page continued (72) inventor Shinobu Akabira Osaka Prefecture Kadoma Oaza Kadoma 1006 address Matsushita Electric industrial Co., Ltd. in the (72) inventor Ohno sharp two Osaka Prefecture Kadoma Oaza Kadoma 1006 address Matsushita Electric industrial Co., Ltd. in the ( 72) inventor Megumiakira Furukawa Osaka Prefecture Kadoma Oaza Kadoma 1006 address Matsushita Electric industrial Co., Ltd. in

Claims (6)

    【特許請求の範囲】 [The claims]
  1. 【請求項1】基板上に、少なくとも第1の誘電体材料薄膜層、波長λのレーザ光線の照射により上記波長λでの光学定数(屈折率n、消衰係数k)が相対的に大である結晶状態と相対的に小であるアモルファス状態との間で光学的特性を可逆的に変化する相変化材料薄膜からなる記録層、第2の誘電体材料薄膜層を順次積層してなる光学的情報記録媒体であって、上記記録層の厚さxは、記録層がアモルファス状態および結晶状態にある時に上記誘電体材料で挟まれた条件下での光透過率T0(am To 1. A substrate, at least a first dielectric material thin film layer, the optical constants (refractive index n, extinction coefficient k) at said wavelength λ by irradiation of a laser beam with a wavelength λ in a relatively large reversibly recording layer of phase change material thin film that changes optical formed by a second dielectric material thin film layer are sequentially laminated optical properties between the amorphous state is relatively small and there crystalline state an information recording medium, the thickness x of the recording layer, the light transmittance under conditions where the recording layer is sandwiched by the dielectric material when in the amorphous and crystalline states T0 (am
    o)とT0(cry)の差、ΔT0(=T0(amo) o) and T0 (the difference between the cry), ΔT0 (= T0 (amo)
    −T0(cry))が20%となる厚さよりも薄く選び、よって上記波長λの照射レーザ光線の内で上記記録層で吸収される比率(以降吸収率と呼ぶ)ならびに上記記録媒体から反射される比率(以降反射率と呼ぶ)を上記記録層がアモルファス状態である場合にはそれぞれA -T0 (cry)) is chosen smaller than the thickness to be 20%, thus referred to as a ratio (hereinafter absorption rate that is absorbed by the recording layer of the irradiated laser beam having the wavelength lambda) and reflected from said recording medium that ratio, respectively (hereinafter referred to as reflectance) and when the recording layer is in the amorphous state a
    (amo)およびR(amo)、また記録層が結晶状態である場合にはそれぞれA(cry)およびR(cr (Amo) and R (amo), also respectively when the recording layer is in the crystalline state A (cry) and R (cr
    y)として、2つの状態間での吸収率の差ΔA(=A As y), the difference in absorptivity between the two states .DELTA.A (= A
    (cry)−A(amo))および反射率の差ΔR(= (Cry) -A (amo)) and the difference in reflectance [Delta] R (=
    R(cry)−R(amo))がΔA≧5%およびΔR R (cry) -R (amo)) is .DELTA.A ≧ 5% and ΔR
    ≧15%の2条件を同時に満足する書換え可能な光学的情報記録媒体。 ≧ 15% of the rewritable optical information recording medium at the same time satisfying the two conditions.
  2. 【請求項2】記録層の厚さxをΔT0(=T0(am The thickness x of 2. A recording layer ΔT0 (= T0 (am
    o)−T0(cry))=25%となる膜厚よりも薄く選び、吸収率の差ΔA≧10%とした請求項1記載の光学的情報記録媒体。 o) -T0 (cry)) = 25% and the film chosen smaller than the thickness, the optical information recording medium according to claim 1, wherein the the difference .DELTA.A ≧ 10% of the absorption rate.
  3. 【請求項3】記録層の厚さxをΔT0(=T0(am The thickness x of 3. A recording layer ΔT0 (= T0 (am
    o)−T0(cry))=25%となる膜厚よりも薄く選び、反射率の差ΔR≧20%とした請求項1記載の光学的情報記録媒体。 o) -T0 (cry)) = 25% and the film chosen smaller than the thickness, the optical information recording medium according to claim 1, wherein the the difference [Delta] R ≧ 20% reflectivity.
  4. 【請求項4】誘電体材料薄膜をZnS−SiO 2 、記録層をGe−Sb−Teとし、記録層の厚さを40nm以下とした請求項1記載の光学的情報記録媒体。 4. A dielectric material thin film ZnS-SiO 2, the recording layer was Ge-Sb-Te, the optical information recording medium according to claim 1, wherein the thickness of the recording layer was 40nm or less.
  5. 【請求項5】誘電体材料薄膜をZnS−SiO 2 、記録層をGe−Sb−Teとし、記録層の厚さを25nm以下とした請求項1記載の光学的情報記録媒体。 5. A dielectric material thin film ZnS-SiO 2, the recording layer was Ge-Sb-Te, the optical information recording medium according to claim 1, wherein the thickness of the recording layer was 25nm or less.
  6. 【請求項6】基板上に少なくとも第1の誘電体材料薄膜層、波長λのレーザ光線の照射により上記波長λでの光学定数(屈折率n、消衰係数k)が相対的に大である結晶状態と相対的に小であるアモルファス状態との間で光学的特性を可逆的に変化する相変化物質薄膜からなる記録層および第2の誘電体材料薄膜層を順次積層して成り、上記記録層が結晶状態にある時には記録層がアモルファス状態にある時に比較して15%以上大きな反射率を示し、かつ5%以上大きな吸収率を示す書換え可能な光学的情報記録媒体を構成する方法であって、上記記録層の厚さxは、記録層がアモルファス状態および結晶状態にある時に上記誘電体材料で挟まれた条件下での光透過率T0(amo)とT0(cry)の差、ΔT0(= 6. At least a first dielectric material thin film layer on a substrate, the optical constants of the above wavelength lambda (refractive index n, extinction coefficient k) is relatively large by irradiation of a laser beam having a wavelength lambda made by sequentially stacking a recording layer and a second dielectric material thin film layer made of reversibly changing the phase change material thin film optical properties between the crystalline state and the amorphous state is relatively small, the recording when the layer is in the crystalline state was in a way to configure a rewritable optical information recording medium showing a comparison to show the large reflection ratio of 15% or more, and high absorption rate of 5% or more when it is in the recording layer is amorphous Te, the thickness x of the recording layer, the difference in light transmittance under conditions where the recording layer is sandwiched by the dielectric material when in the amorphous and crystalline states T0 (amo) and T0 (cry), .DELTA.T0 (=
    T0(amo)−T0(cry))=20%となる膜厚よりも薄く選び、その上で上記第1および第2の誘電体材料薄膜層の厚さd1,d2を様々に仮定して、マトリクス法により、上記記録膜がアモルファス状態にある場合、結晶状態にある場合の反射率、吸収率をそれぞれ算出し、上記条件を満たす誘電体厚さd1,d2の組合せを求める光学的情報記録媒体の設計方法。 T0 (amo) -T0 (cry)) = 20% and a film wish thinner than, the thickness d1, d2 of the first and second dielectric material thin film layer thereon by various assumptions, the matrix method, when the recording film is in the amorphous state, reflectance when in the crystalline state, the absorption rate was calculated, the optical information recording medium to obtain a combination of the above conditions are satisfied dielectric thickness d1, d2 design method.
JP9760792A 1992-04-17 1992-04-17 The optical information recording medium and the structure design method thereof Expired - Fee Related JP3012734B2 (en)

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US08045876 US5424106A (en) 1992-04-17 1993-04-15 Optical information recording medium and method of designing its structure
EP19930106103 EP0566107B1 (en) 1992-04-17 1993-04-15 Optical information recording medium and method of designing its structure
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JPH0863781A (en) * 1994-08-29 1996-03-08 Nec Corp Phase change type optical disk
JPH0877596A (en) * 1994-08-31 1996-03-22 Nec Corp Optical information recording medium
WO1997032304A1 (en) * 1996-02-28 1997-09-04 Asahi Kasei Kogyo Kabushiki Kaisha Method of designing a phase-change optical recording medium, and a phase-change optical recording medium
US5681632A (en) * 1995-02-13 1997-10-28 Matsushita Electric Industrial Co., Ltd. Optical information recording medium
US6268034B1 (en) 1998-08-05 2001-07-31 Matsushita Electric Industrial Co., Ltd. Optical information recording medium and method for producing the same, method for recording and reproducing information thereon and recording/reproducing apparatus
US6343062B1 (en) 1997-09-26 2002-01-29 Matsushita Electric Industrial Co., Ltd Optical disk device and optical disk for recording and reproducing high-density signals
US6388984B2 (en) 1997-08-28 2002-05-14 Matsushita Electric Industrial Co., Ltd. Optical information recording medium and its recording and reproducing method
US6503690B1 (en) 1997-08-12 2003-01-07 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, method for producing the same, and method for recording and reproducing optical information
US6821707B2 (en) 1996-03-11 2004-11-23 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, producing method thereof and method of recording/erasing/reproducing information
US7037413B1 (en) 1996-03-11 2006-05-02 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, producing method thereof and method of recording/erasing/reproducing information

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0863781A (en) * 1994-08-29 1996-03-08 Nec Corp Phase change type optical disk
JPH0877596A (en) * 1994-08-31 1996-03-22 Nec Corp Optical information recording medium
US5681632A (en) * 1995-02-13 1997-10-28 Matsushita Electric Industrial Co., Ltd. Optical information recording medium
WO1997032304A1 (en) * 1996-02-28 1997-09-04 Asahi Kasei Kogyo Kabushiki Kaisha Method of designing a phase-change optical recording medium, and a phase-change optical recording medium
US6149999A (en) * 1996-02-28 2000-11-21 Asahi Kasei Kogyo Kabushiki Kaisha Method of designing a phase-change optical recording medium, and a phase-change optical recording medium
US6821707B2 (en) 1996-03-11 2004-11-23 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, producing method thereof and method of recording/erasing/reproducing information
US7037413B1 (en) 1996-03-11 2006-05-02 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, producing method thereof and method of recording/erasing/reproducing information
US6503690B1 (en) 1997-08-12 2003-01-07 Matsushita Electric Industrial Co., Ltd. Optical information recording medium, method for producing the same, and method for recording and reproducing optical information
US6388984B2 (en) 1997-08-28 2002-05-14 Matsushita Electric Industrial Co., Ltd. Optical information recording medium and its recording and reproducing method
US6343062B1 (en) 1997-09-26 2002-01-29 Matsushita Electric Industrial Co., Ltd Optical disk device and optical disk for recording and reproducing high-density signals
US6268034B1 (en) 1998-08-05 2001-07-31 Matsushita Electric Industrial Co., Ltd. Optical information recording medium and method for producing the same, method for recording and reproducing information thereon and recording/reproducing apparatus

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