JP2657967B2 - Glass substrate for recording medium, recording medium, and method for producing them - Google Patents
Glass substrate for recording medium, recording medium, and method for producing themInfo
- Publication number
- JP2657967B2 JP2657967B2 JP63182465A JP18246588A JP2657967B2 JP 2657967 B2 JP2657967 B2 JP 2657967B2 JP 63182465 A JP63182465 A JP 63182465A JP 18246588 A JP18246588 A JP 18246588A JP 2657967 B2 JP2657967 B2 JP 2657967B2
- Authority
- JP
- Japan
- Prior art keywords
- recording medium
- glass substrate
- layer
- stress layer
- tensile stress
- 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
Links
- 239000000758 substrate Substances 0.000 title claims description 75
- 239000011521 glass Substances 0.000 title claims description 68
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 238000000034 method Methods 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 7
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 6
- 238000005342 ion exchange Methods 0.000 claims description 6
- 238000003426 chemical strengthening reaction Methods 0.000 claims description 4
- 239000010410 layer Substances 0.000 description 41
- 239000007858 starting material Substances 0.000 description 11
- 239000000203 mixture Substances 0.000 description 7
- 239000011734 sodium Substances 0.000 description 6
- 229910001415 sodium ion Inorganic materials 0.000 description 6
- 239000011651 chromium Substances 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- 230000006378 damage Effects 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 239000011241 protective layer Substances 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000314 lubricant Substances 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 239000005361 soda-lime glass Substances 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- 239000005345 chemically strengthened glass Substances 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 239000006058 strengthened glass Substances 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910002441 CoNi Inorganic materials 0.000 description 1
- 229910005900 GeTe Inorganic materials 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 229910000420 cerium oxide Inorganic materials 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229910052711 selenium Inorganic materials 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 229910052714 tellurium Inorganic materials 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Surface Treatment Of Glass (AREA)
- Magnetic Record Carriers (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、磁気記録媒体、光磁気記録媒体及び光記録
媒体等の記録媒体及びこれら記録媒体の基板として用い
られる記録媒体用ガラス基板並びにそれらの製造方法に
関するものである。The present invention relates to a recording medium such as a magnetic recording medium, a magneto-optical recording medium, and an optical recording medium, a glass substrate for a recording medium used as a substrate of the recording medium, and a recording medium. And a method for producing the same.
従来、この種の記録媒体として特開昭62−143243号公
報に記載されているものがある。すなわち化学強化され
た、円板状のガラス基板上にAs−Te−Se系の記録層を設
けた光記録媒体が知られている。また、一般に化学強化
されたガラス基板として、SiO2を主成分とし、イオン交
換されるイオンとしてナトリウムイオンを含有したソー
ダライルガラスからなる基板を出発材料とし、この出発
材料をKNO3溶融塩中に浸漬して、NaイオンとＫイオンと
を置換して、このガラス基板表面に圧縮応力層を形成す
ることにより強化したものが知られている。したがって
ソーダライムガラスを出発材料とし、化学強化されたガ
ラス基板上に記録層を設けた記録媒体は知られている。Conventionally, as this type of recording medium, there is one described in JP-A-62-143243. That is, an optical recording medium in which an As-Te-Se-based recording layer is provided on a chemically strengthened disk-shaped glass substrate is known. In general as chemically strengthened glass substrate, the SiO 2 as a main component, a substrate made of soda Lyle glass containing sodium ions as a starting material as an ion to be ion-exchanged, the starting material KNO 3 in the molten salt It is known that the glass substrate is strengthened by immersion to replace Na ions and K ions and form a compressive stress layer on the surface of the glass substrate. Therefore, a recording medium in which a recording layer is provided on a chemically strengthened glass substrate using soda lime glass as a starting material is known.
しかしながら、従来の記録媒体は、そのガラス基板が
化学強化されていることから、表面疵（クラック）に基
づく破壊に対して未強化のガラス基板上に記録層を設け
た記録媒体よりも高い強度を有するが、それでもクラッ
クが基板の厚さ方向において20μｍも深く入りこむと高
回転速度では破壊してしまう問題点がある。例えば、圧
縮応力層の深さが20μｍ未満で直径が130mm、厚さ1.9mm
のソーダライムガラスを強化したガラス基板上に磁性層
を設けた記録媒体は、30,000rpmの高速回転で破壊され
てしまう。However, a conventional recording medium has a higher strength than a recording medium having a recording layer provided on a non-reinforced glass substrate against destruction due to surface defects (cracks) because the glass substrate is chemically strengthened. However, there is still a problem that if the cracks penetrate as deep as 20 μm in the thickness direction of the substrate, the cracks are broken at a high rotation speed. For example, the depth of the compressive stress layer is less than 20 μm, the diameter is 130 mm, and the thickness is 1.9 mm.
A recording medium in which a magnetic layer is provided on a glass substrate reinforced with soda lime glass is destroyed by a high-speed rotation of 30,000 rpm.
上述の課題を解決するために、本発明にかかる記録媒
体用ガラス基板は、 （構成１）表面側から厚さ方向に内部に向かって順次圧
縮応力層及び引張応力層を形成した記録媒体用ガラス基
板であって、 前記引張応力層の引張応力の最大値を4Kg/mm2以下と
したことを特徴とする構成とし、 この構成１の態様として、 （構成２）前記ガラス基板をその組成中に少なくともSi
O2、Na2O及びLiO2を含むガラス材料で構成したことを特
徴とする構成、 また、構成１又は２の態様として、 （構成３）前記圧縮応力層の厚さを50μｍ以上したこと
を特徴とする構成とし、 さらに構成２又は３の態様として、 （構成４）前記ガラス材料のNa2Oの含有量が10重量％以
上であり、かつ、LiO2の含有量が５重量％以上であるこ
とを特徴とする構成とした。In order to solve the above-mentioned problem, a glass substrate for a recording medium according to the present invention comprises: (Structure 1) a glass for a recording medium in which a compressive stress layer and a tensile stress layer are sequentially formed from the surface side to the inside in the thickness direction. A substrate, wherein the maximum value of the tensile stress of the tensile stress layer is set to 4 kg / mm 2 or less. As an aspect of the configuration 1, (Configuration 2) The glass substrate is contained in the composition. At least Si
A configuration characterized by comprising a glass material containing O 2 , Na 2 O and LiO 2 , and as an aspect of Configuration 1 or 2, (Configuration 3) wherein the thickness of the compressive stress layer is 50 μm or more. As a feature of the feature, and as an aspect of the feature 2 or 3, (Structure 4) wherein the glass material has a Na 2 O content of 10% by weight or more and a LiO 2 content of 5% by weight or more. The configuration is characterized by the following.
また、本発明にかかる記録媒体は、 （構成５）基板表面に少なくとも記録層が形成された記
録媒体であって、前記基板を構成１ないし４のいずれか
の記録媒体用ガラス基板で構成したことを特徴とする構
成とし、 この構成５の態様として、 （構成６）前記記録層が磁性層であることを特徴とする
構成とした。Further, the recording medium according to the present invention is: (Structure 5) a recording medium having at least a recording layer formed on a substrate surface, wherein the substrate is formed of a glass substrate for a recording medium according to any one of Structures 1 to 4. According to a fifth aspect of the present invention, (Structure 6) the recording layer is a magnetic layer.
また、本発明にかかる記録媒体用ガラス基板の製造方
法は、 （構成７）構成１ないし４のいずれかの記録媒体用ガラ
ス基板を製造する記録媒体用ガラス基板の製造方法にお
いて、 前記圧縮応力層及び引張応力層をイオン交換による化
学強化法によって形成することを特徴とする構成とし
た。The method for manufacturing a glass substrate for a recording medium according to the present invention may further include: (Structure 7) The method for manufacturing a glass substrate for a recording medium according to any one of Structures 1 to 4, wherein: And the tensile stress layer is formed by a chemical strengthening method by ion exchange.
さらに、本発明にかかる記録媒体の製造方法は、 （構成８）構成５又は６の記録媒体を製造する記録媒体
の製造方法において、 前記記録媒体用ガラス基板の圧縮応力層及び引張応力
層をイオン交換による化学強化法によって形成すること
を特徴とする構成としたものである。Further, in the method for manufacturing a recording medium according to the present invention, (Structure 8) The method for manufacturing a recording medium according to Structure 5 or 6, wherein the compressive stress layer and the tensile stress layer of the recording medium glass substrate are ionized. The structure is characterized by being formed by a chemical strengthening method by exchange.
［作用］ 上述の構成１によれば、ガラス基板表面から入る一般
的なクラックに対して圧縮応力層の作用により回転等に
よる破壊の防止が可能になり、かつ、この圧縮応力層を
厚さを超えるクラックが生じても圧縮応力層よりさらに
基板内部にある引張応力層の引張応力の最大値を4Kg/mm
2以下としたことにより、十分な強度を維持することが
可能になった。構成１の効果は構成２のように、ガラス
基板をその組成中に少なくともSiO2、Na2O及びLiO2を含
むガラス材料で構成した場合により効果的である。ま
た、その場合、圧縮応力層の厚さを構成３のように、50
μｍ以上にすれば、通常のクラックに十分に対応できる
ものが得られる。さらに、ガラス基板を構成するガラス
材料の組成として、構成４のように、SiO2の含有量が10
重量％以上であり、かつ、LiO2の含有量が５重量％以上
であることがよい望ましい。[Operation] According to the above-described configuration 1, it is possible to prevent a general crack entering from the glass substrate surface from being broken by rotation or the like by the action of the compressive stress layer, and to reduce the thickness of the compressive stress layer. The maximum value of the tensile stress of the tensile stress layer inside the substrate even more than the compressive stress layer even if a crack exceeding 4 kg / mm
By setting it to 2 or less, it was possible to maintain sufficient strength. The effect of the constitution 1 is more effective when the glass substrate is composed of a glass material containing at least SiO 2 , Na 2 O and LiO 2 in the composition as in the constitution 2 . In this case, the thickness of the compressive stress layer is set to 50
When the thickness is at least μm, a material which can sufficiently cope with ordinary cracks can be obtained. Further, as the composition of the glass material constituting the glass substrate, the content of SiO 2 is 10
% Or more, and the content of LiO 2 is preferably 5% by weight or more.
また、構成５及び６によれば、ガラス基板の特徴を生
かしつつ、耐久性に富んだ記録媒体を得ることができ
る。Further, according to the configurations 5 and 6, it is possible to obtain a recording medium with high durability while utilizing the characteristics of the glass substrate.
さらに構成７によれば、比較的容易に構成１ないし４
の記録媒体用ガラス基板を得ることができ、構成８によ
れば、比較的容易に構成５及び６の記録媒体を得ること
ができる。Further, according to Configuration 7, Configurations 1 to 4 can be relatively easily performed.
According to Configuration 8, the recording medium of Configurations 5 and 6 can be obtained relatively easily.
［実施例］ 以下、本発明の一実施例にかかる磁気記録媒体、磁気
記録媒体用ガラス基板及びそれらの製造方法を第１図〜
第３図に基づき詳細に説明する。EXAMPLES Hereinafter, a magnetic recording medium, a glass substrate for a magnetic recording medium, and a method of manufacturing the same according to an embodiment of the present invention will be described with reference to FIGS.
This will be described in detail with reference to FIG.
本例の磁気記録媒体１は第１図に示すように、外径13
0mm、内径（中央に形成された穴の直径）40mm及び厚さ
1.9mmの円板上に加工され、かつその主表面（後記する
磁性層13を設ける側の表面）を酸化セリウムにより研磨
され（表面粗さRa＝10〜20μｍ）、さらに後述する方法
により化学強化され、引張応力が3.7kg/mm2であり、圧
縮応力層が基板表面から厚さ方向（深さ）で115μｍま
で至っているガラス基板11と、このガラス基板11上に順
次積層された、クロム（Cr）からなる下地層12（膜厚/:
2000Å）、コバルト（Co）とニッケル（Ni）とクロムと
からなる記録層である磁性層13（膜厚:700Å）、炭素
（Ｃ）からなる保護層14（膜厚:300Å）及びフルオロカ
ーボン系の潤滑剤（例えばMonteflous社製のFomblin A
M2001）からなる潤滑層15（膜厚:30Å）からなる多層膜
16とからなるものである。なお、Crからなる下地層12、
CoNiCrからなる磁性層13及びＣからなる保護層14は何れ
もDCマグネトロンスパッタ法により成膜され、それぞれ
Crからなるターゲット、CoNiCrからなるターゲット及び
Ｃからなるターゲットが用いられる。また、潤滑層15
は、保護層14まで積層されガラス基板11をスピンコータ
上に設置し、保護層14上に前述した潤滑剤を滴下してス
ピンコート法により塗布して形成する。As shown in FIG. 1, the magnetic recording medium 1 of this embodiment has an outer diameter of 13 mm.
0mm, inner diameter (diameter of the hole formed in the center) 40mm and thickness
It is processed on a 1.9 mm disk and its main surface (the surface on the side on which the magnetic layer 13 described later is provided) is polished with cerium oxide (surface roughness Ra = 10 to 20 μm) and further chemically strengthened by the method described later. A glass substrate 11 having a tensile stress of 3.7 kg / mm 2 and a compressive stress layer reaching 115 μm in the thickness direction (depth) from the substrate surface, and chromium ( Underlayer 12 (film thickness :: Cr)
2000 mm), a magnetic layer 13 (thickness: 700 mm), which is a recording layer composed of cobalt (Co), nickel (Ni), and chromium; a protective layer 14 (thickness: 300 mm) made of carbon (C); Lubricants (eg Fomblin A from Monteflous)
M2001) Multilayer film consisting of a lubricating layer 15 (thickness: 30 mm)
It consists of 16. The underlayer 12 made of Cr,
Both the magnetic layer 13 made of CoNiCr and the protective layer 14 made of C are formed by DC magnetron sputtering, and
A target made of Cr, a target made of CoNiCr, and a target made of C are used. The lubrication layer 15
Is formed by stacking the glass substrate 11 on the protective layer 14 and placing the glass substrate 11 on a spin coater, dropping the above-described lubricant onto the protective layer 14 and applying the lubricant by a spin coating method.
次に、強化されたガラス基板11の強化方法について説
明する。なお、強化されたガラス基板11の出発材料のガ
ラス基板は、SiO2を約64wt％、Na2Oを約10wt％及びLiO2
を約6wt％含むものであり、K2Oは含んでいない。Next, a method of strengthening the strengthened glass substrate 11 will be described. The glass substrate as a starting material of the reinforced glass substrate 11 is composed of about 64 wt% of SiO 2 , about 10 wt% of Na 2 O, and LiO 2
Of about 6 wt%, and does not contain K 2 O.
（工程１）先ず前述した方法で、円板状に加工しその主
表面を研磨した、出発材料からなるガラス基板を予熱炉
中に入れる。(Step 1) First, a glass substrate made of a starting material and processed into a disk shape and whose main surface is polished by the above-described method is placed in a preheating furnace.
（工程２）次に予熱炉中の雰囲気を室温から約１時間で
約300℃まで昇温し出発材料からなるガラス基板を予熱
する。(Step 2) Next, the temperature of the atmosphere in the preheating furnace is raised from room temperature to about 300 ° C. in about one hour to preheat the glass substrate made of the starting material.
（工程３）約400℃のKNO360％とNaNO340％の混合溶融塩
中に約４時間浸漬して出発材料のガラス基板を化学強化
する。なお、この強化において、先ず出発材料のガラス
基板中のLiイオンが混合溶融塩中のNaイオンと一部イオ
ンが交換される。次に出発材料のガラス基板中のNaイオ
ン（先にLiイオンと交換したNaイオンを含む。）が混合
溶融中のＫイオンと一部イオン交換される。(Step 3) The glass substrate as a starting material is chemically strengthened by immersing in a mixed molten salt of 60% KNO 3 and 40% NaNO 3 at about 400 ° C. for about 4 hours. In this strengthening, Li ions in the glass substrate as a starting material are partially exchanged with Na ions in the mixed molten salt. Next, Na ions (including Na ions previously exchanged for Li ions) in the glass substrate as a starting material are partially ion-exchanged with K ions during mixed melting.
（工程４）イオン交換された（強化された）ガラス基板
11は混合溶融塩から取り出され徐冷される。(Step 4) Ion-exchanged (tempered) glass substrate
11 is taken out from the mixed molten salt and cooled slowly.
その後、強化されたガラス基板11は、純水、イソプロ
ピルアルコール及びフロン（デュポン社商標）により順
次洗浄・乾燥する。そして、前述した下地層12等からな
る多層膜16を積層する工程を行なう。Thereafter, the reinforced glass substrate 11 is sequentially washed and dried with pure water, isopropyl alcohol and Freon (trademark of DuPont). Then, the above-described step of laminating the multilayer film 16 including the underlayer 12 and the like is performed.
前述した工程１〜工程４を経て強化されたガラス基板
11は、第２図の曲線Ａに示すような応力分布を有し、引
張応力は最大で3.7kg/mm2、圧縮応力層はガラス基板11
の基板表面から深さ115μｍまで形成されている。また
引張応力は、圧縮応力層よりさらにガラス基板11の内部
に生じている。したがってクラックの深さが基板表面か
ら115μｍであっても十分に耐久性を有する。また、ク
ラックが115μｍよりも１μｍや２μｍ大きくても十分
に耐久性を有する。ここで、第３図に示す引張応力−破
壊時間との関係を示す図は、一例として１μｍの深さの
クラックが4kg m/mm2の引張応力によって成長し、ガラ
ス基板が破壊する時間が10年であることを示している。
すなわち、第３図を、例えばクラックの深さが116μｍ
であっても、圧縮応力層の深さ115μｍを超えた値Ｃ＝
１μｍを有するガラス基板に引張応力を付加したとき破
壊するまでの時間を示すものとみることができる。それ
ゆえ、クラックの深さが116μｍであって引張応力が4kg
/mm2であっても約10年間十分に耐えることから、若干圧
縮応力層よりも深いクラックがあっても十分に耐久性を
有する。The glass substrate strengthened through the above-described steps 1 to 4
11 has a stress distribution as shown by a curve A in FIG. 2, the tensile stress is 3.7 kg / mm 2 at the maximum, and the compressive stress layer is a glass substrate 11.
From the substrate surface to a depth of 115 μm. Further, the tensile stress is generated further inside the glass substrate 11 than the compressive stress layer. Therefore, even if the crack depth is 115 μm from the substrate surface, it has sufficient durability. Even if the cracks are larger than 115 μm by 1 μm or 2 μm, they have sufficient durability. Here, FIG. 3 shows the relationship between the tensile stress and the fracture time. As an example, a crack having a depth of 1 μm grows by a tensile stress of 4 kg m / mm 2 and the time required for the glass substrate to fracture is 10 times. Indicates that it is a year.
That is, FIG. 3 shows that the crack depth is 116 μm, for example.
However, even if the value of the compressive stress layer exceeds the depth of 115 μm C =
It can be considered to indicate the time until breaking when a tensile stress is applied to a glass substrate having 1 μm. Therefore, the crack depth is 116 μm and the tensile stress is 4 kg
/ mm 2 can withstand enough for about 10 years, so it has sufficient durability even with cracks slightly deeper than the compressive stress layer.
以上のような特性を有するガラス基板11上に磁性層13
を設けた本例の磁気記録媒体１を、モータのシャフトに
媒体１の穴を嵌合・挿入して回転し、その回転破壊試験
をした結果35,000rpmでも破壊を生じない。なお、同様
の形状、大きさを有する従来のガラス基板１（ソーダラ
イムガラスを化学強化したもの。）上に本例と同様に多
層膜16を積層した従来の磁気記録媒体では26,000〜28,0
00rpmの回転で破壊してしまう。また、本例の磁気記録
媒体１と前述した従来の磁気記録媒体とをそれぞれ落下
試験した結果、本例の磁気記録媒体１は10000回以上繰
り返し落下させても破壊せず、一方従来の磁気記録媒体
は300〜500回の繰り返し落下で破壊してしまう。なお、
この落下試験方法は、プラスティックタイル（例えば田
島応用化工（株）製Ｐタイル厚さ2.0mm）で覆ったコン
クリート床の上方よりガラス基板の中心で1mの高さから
落下させ、ガラス基板の側部が床と衝突する、つまり、
ガラス基板面と床面が直角になる様に自由落下衝撃テス
トを行うものであり、基板破損検知にて破損を確認する
迄、約15秒に１回の割合で繰り返し落下を行うものであ
る。The magnetic layer 13 is formed on the glass substrate 11 having the above characteristics.
The magnetic recording medium 1 of the present example provided with is rotated by fitting and inserting the hole of the medium 1 into the shaft of the motor, and as a result of a rotational breakdown test, it does not break even at 35,000 rpm. A conventional magnetic recording medium in which a multilayer film 16 is laminated on a conventional glass substrate 1 (a soda-lime glass chemically strengthened) having a similar shape and size in the same manner as in this example is 26,000 to 28,0.
It is destroyed by rotation of 00rpm. Also, as a result of a drop test of the magnetic recording medium 1 of the present example and the above-described conventional magnetic recording medium, the magnetic recording medium 1 of the present example did not break even when dropped repeatedly 10,000 times or more. The medium is destroyed by repeatedly dropping 300 to 500 times. In addition,
In this drop test method, a glass tile is dropped from a height of 1 m at the center of the glass substrate from above a concrete floor covered with plastic tiles (for example, P-tile thickness 2.0 mm manufactured by Tajima Kagaku Kogyo Co., Ltd.). Collides with the floor,
A free fall impact test is performed so that the glass substrate surface and the floor surface are at a right angle, and the device is repeatedly dropped about once every 15 seconds until damage is confirmed by substrate damage detection.
本発明は前記実施例に限らず以下のものであってもよ
い。The present invention is not limited to the above embodiment, but may be the following.
先ず、強化されたガラス基板の引張応力の値及び圧縮
応力層の深さはそれぞれ3.7kg/mm2及び115μｍに限ら
ず、4kg/mm2以下及び少なくとも50μｍであれば、一般
に生ずる深さ50μｍまでのクラック及びこれより若干大
きいクラックに対して破壊防止効果を有する。また、強
化されたガラス基板の出発材料のガラス基板の組成は、
前記実施例の組成に限らず、イオン交換処理し化学強化
された後、引張応力4kg/mm2以下及び圧縮応力層が発生
している深さが少なくとも50μｍとなる組成であればよ
い。なお、SiO2とNa2OとLiO2とを含有し、Na2Oが少なく
とも10wt％及びLiO2が少なくとも5wt％含有しているガ
ラスが出発材料として望ましい。また、イオン交換する
条件も前記実施例に限らず、溶融塩の温度360℃、時間1
6時間等の他の条件でもよい。すなわち、前述している
ように引張応力が4kg/mm2以下、圧縮応力層の深さが少
なくとも50μｍとなる条件であればよい。また、前記実
施例に磁気記録媒体のみならず、磁性層がCoNi、CoNiPt
及びCoNiCrPt等からなるもの等の他の磁気記録媒体でも
よい。また記録層がTe、Se、GeTe等からなる光記録媒体
やGdFe、TbFe、TbFeCo、NdDyFe、NdDyFeCo等からなる記
録層を有する光磁気記録媒体にも適用することができ
る。さらに、ガラス基板は円板状であったが、他の形状
のものにも適用できることはいうまでもない。First, each of the depth values and the compressive stress layer of reinforced glass substrate tensile stress is not limited to 3.7 kg / mm 2 and 115 .mu.m, if 4 kg / mm 2 or less and at least 50 [mu] m, generally up to produce depth 50 [mu] m Has a crack-preventing effect on cracks having a smaller size and cracks slightly larger than the cracks. Also, the composition of the glass substrate of the starting material of the strengthened glass substrate is:
The composition is not limited to the composition of the above-described embodiment, and any composition may be used as long as it has a tensile stress of 4 kg / mm 2 or less and a depth at which a compressive stress layer is generated of at least 50 μm after being chemically strengthened by ion exchange treatment. Note that a glass containing SiO 2 , Na 2 O, and LiO 2 and containing at least 10 wt% of Na 2 O and at least 5 wt% of LiO 2 is preferable as a starting material. In addition, the conditions for ion exchange are not limited to those in the above embodiment, and the temperature of the molten salt is 360 ° C. and the time is 1 hour.
Other conditions such as 6 hours may be used. That is, as described above, any condition may be used as long as the tensile stress is 4 kg / mm 2 or less and the depth of the compressive stress layer is at least 50 μm. Further, in the above embodiment, not only the magnetic recording medium but also the magnetic layer is made of CoNi, CoNiPt.
And other magnetic recording media such as those made of CoNiCrPt. Further, the present invention can be applied to an optical recording medium having a recording layer made of Te, Se, GeTe, or the like, or a magneto-optical recording medium having a recording layer made of GdFe, TbFe, TbFeCo, NdDyFe, NdDyFeCo, or the like. Further, although the glass substrate has a disk shape, it is needless to say that the glass substrate can be applied to other shapes.
本発明によれば、一般に発生する50μｍ以下のクラッ
クまたは若干大きいクラックによる、破壊防止や寿命の
低下に対して有効であり、またイオン交換処理により化
学強化されたガラス基板を用いてれば、ガラス基板から
のアルカリイオン（Naイオン）の溶出も防止することが
できる。According to the present invention, cracks of 50 μm or less generally occurring or slightly larger cracks are effective in preventing destruction and shortening the life, and when a glass substrate chemically strengthened by ion exchange treatment is used, Elution of alkali ions (Na ions) from the substrate can also be prevented.
第１図は本発明の一実施例を示す部分断面図、第２図は
この実施例によるガラス基板の応力分布を示す図及び第
３図はクラックの大きさによる、付加した引張応力に対
する破壊時間を示す図である。 １……磁気記録媒体（記録媒体）、11……強化されたガ
ラス基板、13……磁性層（記録層）．FIG. 1 is a partial sectional view showing an embodiment of the present invention, FIG. 2 is a view showing a stress distribution of a glass substrate according to this embodiment, and FIG. 3 is a fracture time with respect to an applied tensile stress depending on the size of a crack. FIG. 1 ... magnetic recording medium (recording medium), 11 ... reinforced glass substrate, 13 ... magnetic layer (recording layer).
フロントページの続き (56)参考文献 特開 昭62−73426（ＪＰ，Ａ) 特開 昭62−187140（ＪＰ，Ａ) 作花済夫、境野照雄、高橋克明編「ガ ラスハンドブック」初版（昭50−９− 30）朝倉書店 Ｐ．494 図４．54Continuation of the front page (56) References JP-A-62-73426 (JP, A) JP-A-62-187140 (JP, A) First edition of "Glass Handbook" (ed. 50-9-30) Asakura Shoten 494 Figure 4.54
Claims (8)
圧縮応力層及び引張応力層を形成した記録媒体用ガラス
基板であって、 前記引張応力層の引張応力の最大値を4Kg/mm2以下とし
たことを特徴とする記録媒体用ガラス基板。1. A glass substrate for a recording medium in which a compressive stress layer and a tensile stress layer are sequentially formed from the surface side toward the inside in the thickness direction, wherein the maximum value of the tensile stress of the tensile stress layer is 4 kg / mm. A glass substrate for a recording medium, characterized in that the number is 2 or less.
SiO2、Na2O及びLiO2を含むガラス材料で構成したことを
特徴とする請求項１に記載の記録媒体用ガラス基板。2. The method according to claim 1, wherein said glass substrate has at least
A glass substrate for a recording medium according to claim 1, characterized by being configured of a glass material containing SiO 2, Na 2 O and LiO 2.
ことを特徴とする請求項１又は２に記載の記録媒体用ガ
ラス基板。3. The glass substrate for a recording medium according to claim 1, wherein the thickness of the compressive stress layer is 50 μm or more.
以上であり、かつ、LiO2の含有量が５重量％以上である
ことを特徴とする請求項２又は３に記載の記録媒体用ガ
ラス基板。4. The glass material has a Na 2 O content of 10% by weight.
The glass substrate for a recording medium according to claim 2 or 3, wherein the content of LiO 2 is 5% by weight or more.
記録媒体であって、前記基板を請求項１ないし４のいず
れかに記載の記録媒体用ガラス基板で構成したことを特
徴とする記録媒体。5. A recording medium having at least a recording layer formed on the surface of a substrate, wherein the substrate is constituted by the glass substrate for a recording medium according to claim 1. .
る請求項５に記載と記録媒体。6. The recording medium according to claim 5, wherein said recording layer is a magnetic layer.
媒体用ガラス基板を製造する記録媒体用ガラス基板の製
造方法において、 前記圧縮応力層及び引張応力層をイオン交換による化学
強化法によって形成することを特徴とする記録媒体用ガ
ラス基板の製造方法。7. The method for manufacturing a glass substrate for a recording medium according to claim 1, wherein the compressive stress layer and the tensile stress layer are formed by a chemical strengthening method by ion exchange. A method for producing a glass substrate for a recording medium, comprising:
る記録媒体の製造方法において、 前記記録媒体用ガラス基板の圧縮応力層及び引張応力層
をイオン交換による化学強化法によって形成することを
特徴とする記録媒体の製造方法。8. The method for manufacturing a recording medium according to claim 5, wherein the compressive stress layer and the tensile stress layer of the recording medium glass substrate are formed by a chemical strengthening method by ion exchange. A method for manufacturing a recording medium, comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63182465A JP2657967B2 (en) | 1988-07-20 | 1988-07-20 | Glass substrate for recording medium, recording medium, and method for producing them |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63182465A JP2657967B2 (en) | 1988-07-20 | 1988-07-20 | Glass substrate for recording medium, recording medium, and method for producing them |
Related Child Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5522897A Division JP2724137B2 (en) | 1997-03-10 | 1997-03-10 | Method for manufacturing glass substrate for recording medium |
| JP9055209A Division JP2724136B2 (en) | 1997-03-10 | 1997-03-10 | Glass substrate for recording medium, recording medium, and method for producing them |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0231325A JPH0231325A (en) | 1990-02-01 |
| JP2657967B2 true JP2657967B2 (en) | 1997-09-30 |
Family
ID=16118735
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63182465A Expired - Lifetime JP2657967B2 (en) | 1988-07-20 | 1988-07-20 | Glass substrate for recording medium, recording medium, and method for producing them |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2657967B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3412804B2 (en) * | 1996-12-26 | 2003-06-03 | Ｈｏｙａ株式会社 | Information recording medium substrate |
| JP6897270B2 (en) * | 2017-04-20 | 2021-06-30 | Ａｇｃ株式会社 | Chemically tempered glass |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6273426A (en) * | 1985-09-26 | 1987-04-04 | Hoya Corp | Production of magnetic recording medium |
| JPH0676224B2 (en) * | 1986-02-13 | 1994-09-28 | 旭硝子株式会社 | Tempered glass manufacturing method |
-
1988
- 1988-07-20 JP JP63182465A patent/JP2657967B2/en not_active Expired - Lifetime
Non-Patent Citations (1)
| Title |
|---|
| 作花済夫、境野照雄、高橋克明編「ガラスハンドブック」初版（昭５０−９−３０）朝倉書店 Ｐ．４９４ 図４．５４ |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0231325A (en) | 1990-02-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3989988B2 (en) | Information recording medium substrate, magnetic disk, and manufacturing method thereof | |
| US6214429B1 (en) | Disc substrates for information recording discs and magnetic discs | |
| US6187441B1 (en) | Glass substrate for information recording medium and magnetic recording medium having the substrate | |
| US7566673B2 (en) | Glass substrate for an information recording medium and information recording medium employing it | |
| JP2837005B2 (en) | Glass for chemical strengthening | |
| JP2886872B2 (en) | Magnetic disk substrate and magnetic disk | |
| KR100188901B1 (en) | A glass-ceramic substrate for a magnetic disk | |
| US6942934B2 (en) | Glass material for a substrate, glass substrate, and information recording medium employing the same | |
| GB2299991A (en) | Chemical strengthening of glass | |
| JP4086210B2 (en) | Substrate for information recording medium | |
| JPH11328601A (en) | Glass board for recording medium, recording medium using glass board and manufacture of glass board for recording medium | |
| EP1067101B1 (en) | Process for preparation of crystallized glass for information recording disk | |
| EP0858974A1 (en) | Glass for information recording medium substrate and glass substrate | |
| JP4726400B2 (en) | Manufacturing method of glass substrate | |
| JP3412804B2 (en) | Information recording medium substrate | |
| US20020009600A1 (en) | Glass-ceramic for substrate of magnetic disk having higher strength and process for the production of the same | |
| JP2657967B2 (en) | Glass substrate for recording medium, recording medium, and method for producing them | |
| JP2837134B2 (en) | Information recording substrate and information recording medium | |
| JP2724136B2 (en) | Glass substrate for recording medium, recording medium, and method for producing them | |
| JP2947131B2 (en) | Glass substrate for magnetic recording medium, method for manufacturing the same, and magnetic recording medium | |
| JP2724137B2 (en) | Method for manufacturing glass substrate for recording medium | |
| JP3130800B2 (en) | Glass composition for magnetic disk substrate and magnetic disk substrate | |
| US20010040150A1 (en) | Glass substrate for information-recording medium and manufacturing method of the glass substrate | |
| JP2657967C (en) | ||
| JP4161756B2 (en) | Glass substrate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term | ||
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090606 Year of fee payment: 12 |