JPH0423639B2 - - Google Patents
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- Publication number
- JPH0423639B2 JPH0423639B2 JP58236423A JP23642383A JPH0423639B2 JP H0423639 B2 JPH0423639 B2 JP H0423639B2 JP 58236423 A JP58236423 A JP 58236423A JP 23642383 A JP23642383 A JP 23642383A JP H0423639 B2 JPH0423639 B2 JP H0423639B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- recording medium
- optical recording
- layer
- glass
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
- G11B7/2531—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising glass
Landscapes
- Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
- Surface Treatment Of Glass (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
- Manufacturing Optical Record Carriers (AREA)
- Thermal Transfer Or Thermal Recording In General (AREA)
Description
本発明は、Te等の記録層を設けた書込・再生
が可能な光学式情報記録媒体や、CdFe等の光磁
気記録層を設けた書込・再生・消去が可能な光磁
気記録媒体などの光記録媒体を構成する新規な光
記録媒体用円板状ガラス基板（以下、「ガラス基
板」という。）、このガラス基板より構成された光
記録媒体に関するものである。
一般に、この種の光記録媒体の一例は、第１図
に示すような基本構成となつている。すなわち、
円板状透明基板１，２上に記録層３，４をそれぞ
れ設け、この円板状透明基板１，２に設けられた
記録層３，４を対向させて設置し、外側スペーサ
５、内側スペーサ６が記録層３，４を覆わないよ
うに挿入されている。そして、前記円板状透明基
板１，２の材質は、PMMA樹脂、ポリカーボネ
ート樹脂、ガラス等が用いられているが、ガラス
は円板状透明基板に要求される光透過率、硬度、
吸水率、像膨張率、表面精度、平面度、表面欠陥
密度及び熱変形温度等の諸特性において優れてお
り、近年ガラスが多く用いられている。
しかしながら、従来のガラス基板の材質は、通
常高価な石英ガラス、無アルカリガラスを避け、
入手が容易で安価、且つ、（Na2O重量％）／
（K2O重量％）の比率が１を越えるガラス、例え
ばソーダライムガラスを使用していたが、この種
のガラス基板では、ガラス表面近傍のNaイオン
の影響により記録層の劣化が著しく促進される傾
向にあり、さらに再生時に誤りが部分的に集中し
て発生し、すなわちバースト誤りが発生して、６
記録媒体の再生機能が阻害される欠点があつた。
また、従来のガラス基板は、記録層の設けられた
ガラス表面とは反対側の表面には、表面近傍の
Naイオンの影響により経時的に曇り（以下、「ヤ
ケ」という。）が発生、このためガラス基板の光
の透過率が著しく低下する欠点があつた。この結
果、従来のガラス基板の光記録媒体は、記録感度
や（R0−Ｒ）／（R0＋Ｒ）（R0：未記録時の記録
層の反射率、Ｒ：記録後の記録層の反射率）で示
される信号コントラストが、極度に悪化するとい
つた欠点があつた。
本発明は、前記の欠点を除去するためのもので
あり、記録層の劣化防止、バースト誤りの防止及
びガラス基板表面のヤケの防止を目的とするガラ
ス基板と光記録媒体を提供することである。
以下、本発明を一実施例に基づき詳細に説明す
る。まず、主要成分の組成比が表１に示すような
外径305mmφ、中心穴径35mmφ、厚さ1.22mmの円
板状のソーダライムガラスを用意する。
The present invention relates to a writable/readable optical information recording medium provided with a recording layer such as Te, a writable/readable/erasable optical information recording medium provided with a magneto-optical recording layer such as CdFe, etc. The present invention relates to a novel disc-shaped glass substrate for optical recording media (hereinafter referred to as "glass substrate") constituting an optical recording medium, and an optical recording medium constructed from this glass substrate. Generally, an example of this type of optical recording medium has a basic configuration as shown in FIG. That is,
Recording layers 3 and 4 are provided on disc-shaped transparent substrates 1 and 2, respectively, and the recording layers 3 and 4 provided on disc-shaped transparent substrates 1 and 2 are placed facing each other, and outer spacer 5 and inner spacer 6 is inserted so as not to cover the recording layers 3 and 4. The disc-shaped transparent substrates 1 and 2 are made of PMMA resin, polycarbonate resin, glass, etc., but glass has the light transmittance, hardness, and
Glass has been widely used in recent years because it has excellent properties such as water absorption, image expansion coefficient, surface precision, flatness, surface defect density, and thermal deformation temperature. However, conventional glass substrate materials usually avoid expensive quartz glass and non-alkali glass.
Easy to obtain, inexpensive, and (Na 2 O weight %) /
Glass with a K 2 O (wt%) ratio exceeding 1, such as soda lime glass, was used, but with this type of glass substrate, the deterioration of the recording layer is significantly accelerated due to the influence of Na ions near the glass surface. Furthermore, during playback, errors tend to be concentrated locally, that is, burst errors occur, resulting in 6.
There was a drawback that the playback function of the recording medium was inhibited.
In addition, in conventional glass substrates, on the surface opposite to the glass surface on which the recording layer is provided, there is a layer near the surface.
Clouding (hereinafter referred to as "staining") occurs over time due to the influence of Na ions, which has the disadvantage of significantly reducing the light transmittance of the glass substrate. As a result, conventional optical recording media with glass substrates have low recording sensitivity, (R 0 - R)/(R 0 + R) (R 0 : reflectance of the recording layer before recording, R: reflectance of the recording layer after recording). The drawback was that the signal contrast, as indicated by reflectance (reflectance), was extremely poor. The present invention is intended to eliminate the above-mentioned drawbacks, and it is an object of the present invention to provide a glass substrate and an optical recording medium for the purpose of preventing deterioration of the recording layer, preventing burst errors, and preventing discoloration on the surface of the glass substrate. . Hereinafter, the present invention will be explained in detail based on one embodiment. First, a disk-shaped soda lime glass having an outer diameter of 305 mmφ, a center hole diameter of 35 mmφ, and a thickness of 1.22 mm and having the composition ratio of the main components shown in Table 1 is prepared.
【表】
次に、低温型イオン交換法により、すなわち前
記ソーダライムガラスの転移温度を越えない温度
域、例えば400℃のＫイオンを含む溶融塩中に、
前記ソーダライムガラスを８時間浸漬し、前記ソ
ーダライムガラスの表面近傍のNaイオンをＫイ
オンに置換し、前記ソーダライムガラスの表面か
ら14μｍに至る厚さの表層部の（Na2O重量
％）／（K2O重量％）の比率を8.9から0.3とし、
表層部を歪層とした。尚、このときソーダライム
ガラスの表面から1μｍの深さまのNa2Oの平均含
有量は3.2重量％であつた。そして、この表層部
以外のソーダライムガラスの残部における
（Na2O重量％）／（K2O重量％）の比率は依然
8.9となつている。このようにして製作したガラ
ス基板のヤケ防止効果をその透過率を示した第２
図を参照して述べる。まず、前記実施例によるガ
ラス基板は、温度60℃、湿度90％の環境下で、40
日経過後であつても透過率は減少しない（同図ａ
線）が、一方比較例として表１で示したソーダラ
イムガラスを前記環境下で、40日経過させると同
図ｂ線に示すように透過率90％が45％に減少して
しまう。次に、（Na2O重量％）／（K2O重量％）
の比率と透過率との関係を第３図に示す。なお、
同図は温度60℃、湿度90％で10日経過後の状態で
ある。同図C1，C2（C1は初期値、C2は10日経過
後）より明らかなとおり、本実施例のように低温
型イオン交換を施して、ガラス基板における
（Na2O重量％）／（K2O重量％）の比率を１以
下に選定した場合、透過率の減少を防止する効果
があり、一方、低温型イオン交換を施していない
（Na2O重量％）／（K2O重量％）が１を越える、
例えばソーダライムガラスは、同図d1，d2（d1は
初期値、d2は10日経過後）に示すとおり、透過率
は減少してしまう。
以上のように、本実施例の光記録媒体用のガラ
ス基板は、低温型イオン交換処理をして、ガラス
基板の表層部を（Na2O重量％）／（K2O重量
％）≦１にすることにより、ヤケを防止して、記
録感度や信号コントラストの低減を防止すること
ができた。尚、（Na2O重量％）／（K2O重量％）
の比率の下限については後述する。
次に、前記実施例のガラス基板を用いた光記録
媒体の一実施例を下記に詳述する。
まず、前記実施例で製作した２枚のガラス基板
（外径305mmφ、中心穴径35mmφ、厚さ1.2mm）の
それぞれのガラス基板上に厚さ300ÅのTeの記録
層を被着し、これらの記録層が対向するように、
前記ガラス基板を設置し、さらに、前記２枚のガ
ラス基板の間に、記録層を封止すると共にガラス
基板間隔を保持するための部材、例えば、スペー
サを挿入し、光記録媒体を製作する。
次に、第４図に基づいて前記実施例の光記録媒
体の記録層の劣化防止効果について詳述する。な
お、この第４図は前記実施例の光記録媒体に使用
された、記録層を被着した１枚のガラス基板を温
度60℃、湿度90％の環境下に放置し、ガラス基板
側より830nｍレーザー光を照射し、記録層の反
射率を求めて作成したものである。また、比較例
として、表１に示すような組成を有するソーダラ
イムガラスのガラス基板上に、前記実施例の光記
録媒体を形成する記録層を被着し、この記録層の
反射率を求める。第４図のｅ線に示す前記実施例
の光記録媒体の記録層の反射率は、初期値を１と
したとき、30日経過しても0.5程度しか低下せず、
一方、同図のｆ線に示す前記ソーダライムガラス
の記録層の反射率は、ガラス基板表面のヤケの影
響も含み、初期値を１としたとき、0.1まで低下
してしまい、ほとんど記録層としての機能を有さ
ない。次にガラス基板の表層部の（Na2O重量
％）／（K2O重量％）の比率と、その比率におい
て、記録層の劣化を温度60℃、湿度90％で前記と
同様に放置し、反射率が例えば初期値より10％低
下するのに要した時間との関係を第５図に示す。
第５図に示す通り、低温型イオン交換をして
（Na2O重量％）／（K2O重量％）の比率が１以
下のｇ線においては、反射率が10％低下する時間
が１を越すｈ線の領域より長くなるが、（Na2O
重量％）／（K2O重量％）の比率が４×10-2未満
となると、（Na2O重量％）／（K2O重量％）の
比率が１のときよりも、反射率が10％低下する時
間が短くなり、同図のｈ線に示すとおり、低温型
イオン交換処理をしてソーダライムガラス
（Na2O重量％）／（K2O重量％）＞１と同様の記
録層の反射率傾向を示してしまう。すなわち、ガ
ラス基板のヤケを防止するのみであれば、ガラス
基板の表層部の（Na2O重量％）／（K2O重量
％）が１以下になるように低温型イオン交換をす
ればよいが、記録層の劣化を防止するためには、
少なくとも（Na2O重量％）／（K2O重量％）が
１の反射率の低減する時間と同程度以上にするに
は（Na2O重量％）／（K2O重量％）の比率を４
×10-2以上の範囲内に選定する必要がある。この
ように、記録層の反射率の低減を初期値より10％
とした場合、（Na2O重量％）／（K2O重量％）
の範囲は４×10-2〜１となるが、反射率の低減す
る値を10％と異なつた値としても、第５図のｇ線
及びｈ線が時間方向で平行移動するので、前記の
４×10-2〜１の範囲となる。つまり、記録層の劣
化の原因となる反射率の低下を防止するために
は、（Na2O重量％）／（K2O重量％）の比率が
４×10-2〜１の範囲内にあることが必要である。
又、このようにイオン交換を施してNaイオンと
Ｋイオンとの重量比を表層部のみ局部的に変える
場合、重量比のみならず表層部の厚さも所定値に
選択しないと安定して所期の反射率低下の防止効
果は得られない。この表層部の厚さの所定値と
は、ソーダライムガラスの表面から厚さが５〜
100μｍの範囲となる値である。この理由は表層
部の厚さが5μｍ未満だとガラス中のアルカリイ
オンの移動や妨げられて、ガラス表面のヤケある
いは記録膜の劣化を十分に防止することができな
い。一方、厚さが100μｍを越えると、応力緩和
が生じるため、ガラス中のアルカリイオンがガラ
ス表面に析出し、前述した5μｍ未満と同様に記
録層の劣化防止効果が低下するためである。さら
に、前記のようにして形成された光記録媒体は、
例えば記録層を150Åにしたとき、記録感度、信
号コントラストが40日経過後であつても初期の
100μs、0.75であり、従来の（Na2O重量％）／
（K2O重量％）の比率が１を越えるガラス基板を
用いた光記録媒体の記録感度（15日経過後、初期
の98μsから320μs）、信号コントラスト（15日経過
後、初期の0.75から0.25）に比較して優れてい
る。また、バースト誤りも、従来の光記録媒体よ
りも数段優れている。
尚、低温型イオン交換されるガラスの（Na2O
重量％）／（K2O重量％）の比率が１を越えてお
ればよいが、さらに望ましくは、１を越え、且
つ、50以下の範囲ががよい。すなわち、（Na2O
重量％）／（K2O重量％）の比率が500を越える
と、ガラス基板の表面近傍のNa2Oは低温型イオ
ン交換により減少するが、ガラス基板内部の
Na2Oの濃度は変化せず光吸収が生じるので、
（Na2O重量％）／（K2O重量％）が１を越えて
50以下が望ましい。また、本発明の光記録媒体に
用いられる記録層は、両ガラス基板にある必要は
なく、一方のガラス基板だけでもよく、記録層の
材質もTeのみならず、Se、GeTe、InTe、TeC、
Te−Ｏ、Te−Ge−Ｏ、Te−As−Ｏ等のカルコ
ゲン元素、カルコゲン化合物、カルコゲン酸化物
でもよく、またGdFe、TeFe、GeTeFe等の光磁
気記録材質であつてもよい。
以上、本発明によれば、光記録媒体用基板の表
面からの厚さが５〜100μｍの範囲内にある表層
部における（Na2O重量％）／（K2O重量％）の
比率を４×10-2〜１の範囲内に、且つ、残部が１
を越えるように、それぞれ選定していることか
ら、前記光記録媒体用基板の表面上に記録膜を形
成して光記録媒体として使用すると、ガラス基板
表面のヤケの防止、光記録媒体の記録層の劣化、
バースト誤りの防止に効果があり、さらにガラス
基板表面の硬度やガラス基板の抗折強度を増加す
る効果がある。[Table] Next, by a low-temperature ion exchange method, that is, in a molten salt containing K ions at a temperature range not exceeding the transition temperature of the soda lime glass, for example, 400 ° C.
The soda lime glass was immersed for 8 hours, Na ions near the surface of the soda lime glass were replaced with K ions, and (Na 2 O wt %) / (K 2 O weight%) ratio from 8.9 to 0.3,
The surface layer was made into a strained layer. At this time, the average content of Na 2 O at a depth of 1 μm from the surface of the soda lime glass was 3.2% by weight. The ratio of (Na 2 O weight %)/(K 2 O weight %) in the remainder of the soda lime glass other than this surface layer is still
It is 8.9. The anti-fading effect of the glass substrate produced in this way is shown in the second section, which shows its transmittance.
This will be explained with reference to the figure. First, the glass substrate according to the above example was heated for 40 minutes in an environment with a temperature of 60°C and a humidity of 90%.
The transmittance does not decrease even after a day has passed (Fig.
On the other hand, when the soda lime glass shown in Table 1 as a comparative example is left in the above environment for 40 days, the transmittance decreases from 90% to 45%, as shown by line b in the figure. Then, (Na 2 O wt %) / (K 2 O wt %)
The relationship between the ratio and transmittance is shown in FIG. In addition,
The figure shows the state after 10 days at a temperature of 60°C and humidity of 90%. As is clear from C 1 and C 2 in the same figure (C 1 is the initial value, C 2 is after 10 days), by performing low-temperature ion exchange as in this example, (Na 2 O weight %) on the glass substrate / (K 2 O weight %) ratio of 1 or less has the effect of preventing a decrease in transmittance; on the other hand, when low temperature ion exchange is not performed (Na 2 O weight %) / ( K O weight%) exceeds 1,
For example, the transmittance of soda lime glass decreases as shown in d 1 and d 2 (d 1 is the initial value, d 2 is after 10 days) in the same figure. As described above, the glass substrate for the optical recording medium of this example was subjected to low-temperature ion exchange treatment to reduce the surface layer of the glass substrate to (Na 2 O weight %)/(K 2 O weight %)≦1. By doing so, it was possible to prevent fading and prevent a reduction in recording sensitivity and signal contrast. In addition, (Na 2 O weight %) / (K 2 O weight %)
The lower limit of the ratio will be described later. Next, an example of an optical recording medium using the glass substrate of the above example will be described in detail below. First, a recording layer of Te with a thickness of 300 Å was deposited on each of the two glass substrates (outer diameter 305 mmφ, center hole diameter 35 mmφ, thickness 1.2 mm) manufactured in the above example. so that the recording layers are facing each other,
The glass substrate is installed, and a member for sealing the recording layer and maintaining the distance between the glass substrates, such as a spacer, is inserted between the two glass substrates to produce an optical recording medium. Next, the effect of preventing deterioration of the recording layer of the optical recording medium of the above embodiment will be described in detail based on FIG. In addition, this figure 4 shows that one glass substrate with a recording layer attached thereto, which was used in the optical recording medium of the above example, was left in an environment with a temperature of 60°C and a humidity of 90%, and a distance of 830 nm from the glass substrate side was measured. It was created by irradiating the recording layer with laser light and determining the reflectance of the recording layer. Further, as a comparative example, a recording layer forming the optical recording medium of the above example was deposited on a glass substrate of soda lime glass having a composition as shown in Table 1, and the reflectance of this recording layer was determined. The reflectance of the recording layer of the optical recording medium of the above example shown by line e in FIG. 4 decreases by only about 0.5 even after 30 days, assuming the initial value is 1.
On the other hand, the reflectance of the soda lime glass recording layer shown by the f line in the same figure includes the influence of the discoloration on the surface of the glass substrate, and when the initial value is set to 1, it decreases to 0.1, and the reflectance is almost as low as the recording layer. It does not have this function. Next, we determined the ratio of (Na 2 O weight %)/(K 2 O weight %) in the surface layer of the glass substrate and the deterioration of the recording layer at that ratio by leaving it at a temperature of 60°C and a humidity of 90% in the same manner as above. , and the time required for the reflectance to decrease, for example, by 10% from the initial value, is shown in FIG.
As shown in Figure 5, when low-temperature ion exchange is performed and the ratio of (Na 2 O weight %)/(K 2 O weight %) is less than 1, the time required for the reflectance to decrease by 10% is 1. (Na 2 O
When the ratio (wt%)/(wt% K 2 O) is less than 4 × 10 -2 , the reflectance is lower than when the ratio (wt% Na 2 O)/(wt% K 2 O) is 1. The time for the 10% drop is shorter, and as shown by the h line in the same figure, the same record as soda lime glass (Na 2 O weight %) / (K 2 O weight %) > 1 after low-temperature ion exchange treatment is obtained. It shows the reflectance tendency of the layer. In other words, if you only want to prevent the glass substrate from burning, you can perform low-temperature ion exchange so that the ratio (Na 2 O weight %)/(K 2 O weight %) of the surface layer of the glass substrate is 1 or less. However, in order to prevent deterioration of the recording layer,
In order to make (Na 2 O weight %) / (K 2 O weight %) at least as long as the reflectance reduction time of 1, the ratio of (Na 2 O weight %) / (K 2 O weight %) is required. 4
It is necessary to select within the range of ×10 -2 or more. In this way, the reflectance of the recording layer is reduced by 10% from the initial value.
Then, (Na 2 O weight %) / (K 2 O weight %)
The range of is 4×10 -2 to 1, but even if the value at which the reflectance is reduced is different from 10%, the g-line and h-line in Fig. 5 move in parallel in the time direction, so the above It is in the range of 4×10 −2 to 1. In other words, in order to prevent a decrease in reflectance that causes deterioration of the recording layer, the ratio of (Na 2 O weight %) / (K 2 O weight %) must be within the range of 4 × 10 -2 to 1. It is necessary that there be.
In addition, when performing ion exchange in this way to locally change the weight ratio of Na ions and K ions only in the surface layer, it is necessary to select not only the weight ratio but also the thickness of the surface layer to a predetermined value to ensure stable and desired results. The effect of preventing the decrease in reflectance cannot be obtained. The predetermined value of the thickness of this surface layer is 5 to 50% thick from the surface of the soda lime glass.
This value is in the range of 100 μm. The reason for this is that if the thickness of the surface layer is less than 5 μm, the movement of alkali ions in the glass will be hindered, making it impossible to sufficiently prevent the glass surface from fading or the recording film from deteriorating. On the other hand, if the thickness exceeds 100 μm, stress relaxation occurs, and alkali ions in the glass precipitate on the glass surface, reducing the deterioration prevention effect of the recording layer as described above when the thickness is less than 5 μm. Furthermore, the optical recording medium formed as described above is
For example, when the recording layer is 150 Å, the recording sensitivity and signal contrast remain the same even after 40 days.
100μs, 0.75, conventional ( Na2O wt%)/
The recording sensitivity (from the initial 98 μs to 320 μs after 15 days) and signal contrast (from the initial 0.75 to 0.25 after 15 days) of an optical recording medium using a glass substrate with a ratio of (K 2 O weight %) exceeding 1 Excellent in comparison. Furthermore, burst errors are also several orders of magnitude better than conventional optical recording media. Note that (Na 2 O
It is sufficient that the ratio (% by weight)/(% by weight of K 2 O) exceeds 1, and more preferably exceeds 1 and is in the range of 50 or less. That is, (Na 2 O
When the ratio (% by weight)/(% by weight of K 2 O) exceeds 500, Na 2 O near the surface of the glass substrate is reduced by low-temperature ion exchange, but Na 2 O inside the glass substrate is reduced.
Since the concentration of Na 2 O does not change and light absorption occurs,
(Na 2 O weight %) / (K 2 O weight %) exceeds 1
Desirably 50 or less. Further, the recording layer used in the optical recording medium of the present invention does not need to be on both glass substrates, and may be on only one glass substrate, and the material of the recording layer is not only Te, but also Se, GeTe, InTe, TeC,
It may be a chalcogen element, a chalcogen compound, or a chalcogen oxide such as Te-O, Te-Ge-O, or Te-As-O, or it may be a magneto-optical recording material such as GdFe, TeFe, or GeTeFe. As described above, according to the present invention, the ratio of (Na 2 O weight %)/(K 2 O weight %) in the surface layer part whose thickness is within the range of 5 to 100 μm from the surface of the optical recording medium substrate is 4. Within the range of ×10 -2 to 1, and the remainder is 1
Therefore, when a recording film is formed on the surface of the optical recording medium substrate and used as an optical recording medium, it is possible to prevent discoloration on the surface of the glass substrate and to reduce the recording layer of the optical recording medium. deterioration of,
This is effective in preventing burst errors, and is also effective in increasing the hardness of the glass substrate surface and the bending strength of the glass substrate.
第１図は一般の光記録媒体の構造を示す断面
図、第２図は本実施例及び比較例の経時変化に対
するガラス基板の透過率示す特性図、第３図は本
実施例及び比較例の（Na2O重量％）／（K2O重
量％）に対するガラス基板の透過率を示す特性
図、第４図は本実施例及び比較例の経時変化に対
する記録層の反射率（初期値を１としたとき）を
示す特性図、第５図は本実施例及び比較例の
（Na2O重量％）／（K2O重量％）に対する記録
層の反射率が初期値より10％低下する時間を示す
特性図である。
Figure 1 is a cross-sectional view showing the structure of a general optical recording medium, Figure 2 is a characteristic diagram showing the transmittance of the glass substrate over time in this example and comparative example, and Figure 3 is a diagram showing the transmittance of the glass substrate over time in this example and comparative example. A characteristic diagram showing the transmittance of the glass substrate with respect to (Na 2 O weight %) / (K 2 O weight %), and Figure 4 shows the reflectance of the recording layer (initial value 1 Fig. 5 shows the time required for the reflectance of the recording layer to decrease by 10% from the initial value for (Na 2 O weight %)/(K 2 O weight %) in the present example and comparative example. FIG.
Claims (1)
円板状透明基板からなる光記録媒体用基板におい
て、 前記円板状透明基板は、前記表面からの厚さが
５〜100μｍの範囲内にある表層部と、該表層部
以外の残部とから成り、（Na2O重量％）／
（K2O重量％）の比率が、前記表層部においては、
４×10-2〜１の範囲内に、前記残部においては１
を越えるように、それぞれ、選定されていること
を特徴とする光記録媒体用基板。 ２ 円板状透明基板からなる２枚の光記録媒体用
基板の少なくとも一方の表面に記録層を形成し、
他方の光記録媒体用基板を前記記録層を形成した
表面側に配置し、前記２枚の光記録媒体用基板間
に、前記記録層を封止すると共に前記基板間隔を
保持する部材を挿入した光記録媒体において、 前記表面に記録層を形成した少なくとも一方の
光記録媒体用基板を構成する円板状透明基板は、
前記表面からの厚さが５〜100μｍの範囲内にあ
る表層部と、該表層部以外の残部とから成り、
（Na2O重量％）／K2O重量％）の比率が、前記
表層部においては、４×10-2〜１の範囲内に、前
記残部においては１を越えるように夫々、選定さ
れていることを特徴とする光記録媒体。[Scope of Claims] 1. An optical recording medium substrate comprising a disc-shaped transparent substrate having a surface provided to form a recording layer, wherein the disc-shaped transparent substrate has a thickness of 5 to 50% from the surface. Consisting of a surface layer within a range of 100 μm and the remainder other than the surface layer, (Na 2 O weight %) /
(K 2 O weight %) in the surface layer part,
Within the range of 4×10 -2 to 1, the remainder is 1
A substrate for an optical recording medium, characterized in that each substrate is selected so as to exceed the following. 2. Forming a recording layer on at least one surface of two optical recording medium substrates made of disc-shaped transparent substrates,
The other optical recording medium substrate was placed on the surface side on which the recording layer was formed, and a member for sealing the recording layer and maintaining the distance between the substrates was inserted between the two optical recording medium substrates. In the optical recording medium, the disk-shaped transparent substrate constituting at least one optical recording medium substrate having a recording layer formed on the surface thereof,
Consisting of a surface layer portion having a thickness from the surface within a range of 5 to 100 μm, and the remainder other than the surface layer portion,
(Na 2 O weight %)/K 2 O weight %) is selected to be within the range of 4×10 -2 to 1 in the surface layer portion and to exceed 1 in the remaining portion. An optical recording medium characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58236423A JPS60129294A (en) | 1983-12-16 | 1983-12-16 | Base for optical recording medium and optical recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58236423A JPS60129294A (en) | 1983-12-16 | 1983-12-16 | Base for optical recording medium and optical recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60129294A JPS60129294A (en) | 1985-07-10 |
| JPH0423639B2 true JPH0423639B2 (en) | 1992-04-22 |
Family
ID=17000532
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58236423A Granted JPS60129294A (en) | 1983-12-16 | 1983-12-16 | Base for optical recording medium and optical recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60129294A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0742140B2 (en) * | 1984-09-22 | 1995-05-10 | 日本板硝子株式会社 | Glass articles that prevent electron beam coloring |
| JPH06104581B2 (en) * | 1987-09-25 | 1994-12-21 | 日本板硝子株式会社 | Method for producing glass article in which coloring by electron beam is prevented |
| JP4467597B2 (en) | 2007-04-06 | 2010-05-26 | 株式会社オハラ | Inorganic composition article |
| JP2013238677A (en) * | 2012-05-11 | 2013-11-28 | Asahi Glass Co Ltd | Reflector |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3477834A (en) * | 1968-05-17 | 1969-11-11 | Ppg Industries Inc | Method for strengthening glass |
| IT1064628B (en) * | 1976-07-12 | 1985-02-25 | Innocenti Santeustacchio Spa | CAGE PERFECTED FOR ROLLING MILL |
| JPS5672332U (en) * | 1979-11-07 | 1981-06-13 | ||
| US4331770A (en) * | 1980-04-21 | 1982-05-25 | Corning Glass Works | Low liquidus glasses for television tube faceplates |
| JPS6023997B2 (en) * | 1980-08-20 | 1985-06-10 | 株式会社日立製作所 | Recording parts |
| JPS57164454A (en) * | 1981-03-31 | 1982-10-09 | Fujitsu Ltd | Treating method for surface of glass substrate for optical recording medium |
| FR2512436B1 (en) * | 1981-09-04 | 1986-04-04 | Saint Gobain Vitrage | MANUFACTURE OF WINDOWS REFLECTING INFRARED RADIATION |
| JPS5852652U (en) * | 1981-10-06 | 1983-04-09 | キヤノン株式会社 | photothermal magnetic recording medium |
| JPS58156554A (en) * | 1982-03-11 | 1983-09-17 | Nippon Electric Glass Co Ltd | Treatment of glass surface |
| EP0449821B1 (en) * | 1988-12-21 | 1994-05-25 | Lam Research Corporation | Chemical vapor deposition reactor and method for use thereof |
-
1983
- 1983-12-16 JP JP58236423A patent/JPS60129294A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60129294A (en) | 1985-07-10 |
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