JPH0198101A - Checking method for magnetic recording medium - Google Patents
Checking method for magnetic recording mediumInfo
- Publication number
- JPH0198101A JPH0198101A JP25694187A JP25694187A JPH0198101A JP H0198101 A JPH0198101 A JP H0198101A JP 25694187 A JP25694187 A JP 25694187A JP 25694187 A JP25694187 A JP 25694187A JP H0198101 A JPH0198101 A JP H0198101A
- Authority
- JP
- Japan
- Prior art keywords
- write current
- head
- recording medium
- magnetic recording
- value
- 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.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims description 10
- 238000007689 inspection Methods 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Landscapes
- Recording Or Reproducing By Magnetic Means (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、非磁性基板上に磁性層を有する磁気記録媒体
の記録性能の検査方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for testing the recording performance of a magnetic recording medium having a magnetic layer on a non-magnetic substrate.
磁気記録媒体は、コンピュータの外部記憶装置として用
いられるハードディスク装置の心臓部品とも言うことが
できる。その記録性能を検査するには測定半径を２ない
し４つに分割し、各半径に所定の値に設定された書き込
み電流によってヘッドで書き込みを行い、次いでヘッド
により読み出して再生出力を得ることにより行っていた
。Magnetic recording media can also be said to be the core component of hard disk drives used as external storage devices for computers. To test the recording performance, divide the measurement radius into 2 or 4 parts, write with a head using a write current set to a predetermined value for each radius, and then read with the head to obtain a playback output. was.
しかし、上記のような検査方法ではヘッドのばらつき、
あるいはヘッドの変形などによる経時変化に対して対応
がとれないため、同一の書き込み電流でも媒体に印加さ
れる磁界が同一でなく、電磁変換特性および信号品質の
ばらつきの原因となり、本来の磁気記録媒体の記録性能
の正しい評価ができないという欠点があった。However, with the above inspection method, head variations,
Alternatively, since it is not possible to deal with changes over time due to deformation of the head, the magnetic field applied to the medium is not the same even with the same write current, causing variations in electromagnetic conversion characteristics and signal quality. The drawback was that it was not possible to accurately evaluate the recording performance of
本発明の目的は、上記の欠点を除いて使用ヘッドの品質
上のばらつきあるいは経時変化によって左右されること
なく、磁気記録媒体に所期の磁界を印加して記録でき、
電磁変換特性および信号品質の検査を行うことができる
磁気記録媒体の検査方法を提供することにある。The purpose of the present invention is to enable recording by applying a desired magnetic field to a magnetic recording medium without being influenced by variations in quality of heads used or changes over time, except for the above-mentioned drawbacks.
An object of the present invention is to provide a method for inspecting a magnetic recording medium that can inspect electromagnetic conversion characteristics and signal quality.
上記の目的を達成するために、本発明の方法は、検査す
べき磁気記録媒体の所定の半径位置上に浮上させたヘッ
ドによる書き込み電流を変化させて磁界を印加し、媒体
の再生出力と書き込み電流の関係を求め、再生出力の飽
和値に対する書き込み電流に依存する電流によって媒体
に磁界を印加して記録性能を測定するものとする。記録
性能測定のための書き込み電流として再生出力の飽和値
の９０％に達する書き込み電流の１．５倍を用いること
が一般的に有効である。In order to achieve the above object, the method of the present invention applies a magnetic field by changing a write current by a head floating above a predetermined radial position of a magnetic recording medium to be inspected. The relationship between the currents is determined, and the recording performance is measured by applying a magnetic field to the medium using a current that depends on the write current for the saturation value of the reproduction output. It is generally effective to use 1.5 times the write current that reaches 90% of the saturation value of the reproduction output as the write current for recording performance measurement.
ヘッドによる磁界の印加によりて磁気記録媒体の磁化は
第２図に示すような履歴曲線をとる。書き込み電流を増
加すると再生出力が飽和するが、通常飽和値の９０％の
再生出力にあたる書き込み電流の１．５倍を用いて書き
込みを行うと第２図のＨ。Due to the application of a magnetic field by the head, the magnetization of the magnetic recording medium takes a history curve as shown in FIG. When the write current is increased, the reproduction output becomes saturated, but when writing is performed using 1.5 times the write current, which corresponds to a reproduction output of 90% of the normal saturation value, H in FIG. 2 is obtained.
に相当する磁界が磁気記録媒体に生じ、印加される磁界
は磁気記録のための適正な値になる。従って、使用上の
適正な条件での記録特性が磁気記録媒体の所定の半径位
置について測定でき、半径位置を変えることにより媒体
全面にわたり信頼性のある検査ができる。A magnetic field corresponding to is generated in the magnetic recording medium, and the applied magnetic field has an appropriate value for magnetic recording. Therefore, the recording characteristics under appropriate usage conditions can be measured at a predetermined radial position of the magnetic recording medium, and by changing the radial position, reliable inspection can be performed over the entire surface of the medium.
第３図は、本発明の一実施例に用いる検査装置を示す、
この装置のスピンドル２に測定する磁気記録媒体ｌを取
り付け、媒体表面上にＺ軸移動ステージ５に取り付けら
れたヘッドアーム４とヘッド３を取り付ける。測定器７
は１！磁変換特性および信号品質を検査する電気回路で
あり、その測定結果を記録するプリンタ８が接続されて
いる。このような構成において、いまスピンドル２を高
速で回転させることにより、ヘッド３が浮上する。FIG. 3 shows an inspection device used in an embodiment of the present invention.
A magnetic recording medium 1 to be measured is attached to the spindle 2 of this apparatus, and a head arm 4 and a head 3 attached to a Z-axis moving stage 5 are attached on the surface of the medium. Measuring device 7
is 1! This is an electric circuit that tests magnetic conversion characteristics and signal quality, and is connected to a printer 8 that records the measurement results. In such a configuration, by rotating the spindle 2 at a high speed, the head 3 floats.
この時ヘッドの浮上量を光の干渉縞により検知し、移動
ステージ５のヘッドアーム４を上下に動がして浮上量を
一定に合わせる０次にヘッド３をキャリッジ６により測
定位置に移動させ、その位置でヘッド３による書き込み
電流に対する再生出力の飽和特性を測定する。飽和特性
をグラフ化したものが第１図である。第１図に示すよう
にヘッド３のばらつきにより同一の磁気記録媒体を測定
しても、ｌ１１１．１２．１３のように異なった結果と
なるが、この飽和曲線から求められる飽和特性の再生出
力最大値の９０％の再生出力にあたる書き込み電流値Ｉ
° の１．５倍の書き込み電流値をとつた場合、磁気記
録媒体に印゛加される磁界は、第２図に示したＨｏ で
あることが確かめられた。このＨｏの磁界は、この磁気
記録媒体への記録の際の最適な状態であり、ヘッドのば
らつきと関係のない条件で電磁変換特性および信号品質
の検査が行えるようになる。このような検査をヘッド３
を半径方向に移動しながら行うことにより、磁気記録媒
体１の全面の検査が行える。しかし、検査効率の上から
複数の半径位置のみで検査を行ってもよい０例えば半径
４７．５＋ｗの磁気記録媒体の半径４５鶴の最外周。At this time, the flying height of the head is detected by optical interference fringes, and the head arm 4 of the moving stage 5 is moved up and down to keep the flying height constant. Next, the head 3 is moved to the measurement position by the carriage 6. At that position, the saturation characteristics of the reproduction output with respect to the write current by the head 3 are measured. FIG. 1 is a graph of the saturation characteristics. As shown in Figure 1, even if the same magnetic recording medium is measured due to variations in the head 3, different results will be obtained as shown in l111.12.13. However, the maximum reproduction output of the saturation characteristic determined from this saturation curve Write current value I corresponding to the reproduction output of 90% of the value
It was confirmed that when a write current value of 1.5 times .degree. is taken, the magnetic field applied to the magnetic recording medium is Ho as shown in FIG. This magnetic field of Ho is the optimum state for recording on this magnetic recording medium, and allows testing of electromagnetic conversion characteristics and signal quality under conditions unrelated to head variations. Head 3 performs such inspection.
By performing this while moving in the radial direction, the entire surface of the magnetic recording medium 1 can be inspected. However, from the viewpoint of inspection efficiency, inspection may be performed only at a plurality of radial positions.For example, the outermost circumference of a magnetic recording medium with a radius of 47.5+w.
半径２１．５ｍの最内周およびその中間の３３．３ｆｉ
の円周部で測定を行う。The innermost circumference with a radius of 21.5m and the middle 33.3fi
Measure at the circumference.
媒体にＨｏ の磁界を印加するために必要な書き込み電
流は、第１図の再生出力１００％に対する書き込み電流
との比からも求められるが、このような書き込み電流値
は第１図かられかるように確定しにくいので９０％の値
を用いて求めることが望ましい、しかし、他の方法、例
えば８０％の再生出力のための値に適正な倍数を乗じて
もよい、なお、第１図に示した飽和特性より求められる
書き込み電流値より、磁気記録媒体の保持力の推定が容
易にできる。The write current required to apply a Ho magnetic field to the medium can also be found from the ratio of the write current to 100% reproduction output in Figure 1, but such a write current value is as shown in Figure 1. Since it is difficult to determine the value, it is desirable to use the 90% value. However, other methods may be used, for example, by multiplying the value for 80% playback output by an appropriate multiple. The coercive force of the magnetic recording medium can be easily estimated from the write current value determined from the saturation characteristics.
本発明によれば、書き込み電流による再生出力の飽和特
性を用いて磁気記録媒体に印加される磁界を一定にする
書き込み電流の設定を可能にし、ヘッドのばらつき、経
時変化による影響を低減でき、磁気記録媒体の信頼性の
高い記録性能を知ることのできる検査方法が得られた。According to the present invention, it is possible to set the write current to keep the magnetic field applied to the magnetic recording medium constant by using the saturation characteristic of the reproduction output due to the write current, and it is possible to reduce the effects of head variations and changes over time. An inspection method has been obtained that allows the highly reliable recording performance of a recording medium to be determined.
同時に飽和特性より得られた書き込み電流値により、磁
気記録媒体の保持力の推定が容易になり、磁気記録装置
の設計に有用なデータを得ることができる。At the same time, the write current value obtained from the saturation characteristics makes it easy to estimate the coercive force of the magnetic recording medium, and it is possible to obtain data useful for designing a magnetic recording device.
第１図は本発明の一実施例に用いる磁気記録媒体への書
き込み電流による再生出力の飽和特性を示す線図、第２
図は磁気記録媒体のＢ−１（履歴曲線図、第３図は本発
明の一実施例のための測定装置を示す要部正面図である
。
１：磁気記録媒体、２ニスピンドル、３：ヘッド、４：
へラドアーム、７：測定器。
代理人ｆ） Ｊ：Ｉ！士 山 口 脹 ＼、” ／
〆第２図
第３図FIG. 1 is a diagram showing saturation characteristics of reproduction output due to write current to a magnetic recording medium used in one embodiment of the present invention, and FIG.
The figure is a B-1 (hysteresis curve diagram) of a magnetic recording medium. FIG. Head, 4:
Helad arm, 7: Measuring instrument. Agent f) J:I! Shi Yamaguchi En ＼、”／
〆Figure 2Figure 3
Claims (1)
させたヘッドによる書き込み電流を変化させて磁界を印
加し、前記媒体の再生出力と前記書き込み電流の関係を
求め、再生出力の飽和値に対する書き込み電流に依存す
る電流によって前記媒体に磁界を印加して記録性能を測
定することを特徴とする磁気記録媒体の検査方法。 ２）特許請求の範囲第１項記載の方法において、記録性
能測定のための書き込み電流の電流値として再生出力の
飽和値の９０％に達する書き込み電流の１．５倍を用い
ることを特徴とする磁気記録媒体の検査方法。[Claims] 1) A magnetic field is applied by changing a write current by a head floating above a predetermined radial position of a magnetic recording medium to be inspected, and the relationship between the reproduction output of the medium and the write current is determined. . A method for inspecting a magnetic recording medium, characterized in that recording performance is measured by applying a magnetic field to the medium using a current that depends on a write current with respect to a saturation value of a reproduction output. 2) The method according to claim 1, characterized in that the current value of the write current for measuring recording performance is 1.5 times the write current that reaches 90% of the saturation value of the reproduction output. Inspection method for magnetic recording media.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62256941A JPH0760481B2 (en) | 1987-10-12 | 1987-10-12 | Inspection method of magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62256941A JPH0760481B2 (en) | 1987-10-12 | 1987-10-12 | Inspection method of magnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0198101A true JPH0198101A (en) | 1989-04-17 |
| JPH0760481B2 JPH0760481B2 (en) | 1995-06-28 |
Family
ID=17299488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62256941A Expired - Fee Related JPH0760481B2 (en) | 1987-10-12 | 1987-10-12 | Inspection method of magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0760481B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6947242B2 (en) | 2002-04-16 | 2005-09-20 | Hitachi Global Storage Technologies Netherlands B.V. | Apparatus and method for dynamic fly height adjustment |
| US8174783B2 (en) | 2009-07-23 | 2012-05-08 | Hitachi Global Storage Technologies Netherlands, B.V. | Testing magnetic disk performance with a single slider simulating sliders of various disk drive systems |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5270818A (en) * | 1975-12-10 | 1977-06-13 | Fuji Photo Film Co Ltd | Method of magnetic sheet recording |
| JPS6262403A (en) * | 1985-09-12 | 1987-03-19 | Mitsubishi Electric Corp | Magnetic recording and reproducing device |
-
1987
- 1987-10-12 JP JP62256941A patent/JPH0760481B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5270818A (en) * | 1975-12-10 | 1977-06-13 | Fuji Photo Film Co Ltd | Method of magnetic sheet recording |
| JPS6262403A (en) * | 1985-09-12 | 1987-03-19 | Mitsubishi Electric Corp | Magnetic recording and reproducing device |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6947242B2 (en) | 2002-04-16 | 2005-09-20 | Hitachi Global Storage Technologies Netherlands B.V. | Apparatus and method for dynamic fly height adjustment |
| US8174783B2 (en) | 2009-07-23 | 2012-05-08 | Hitachi Global Storage Technologies Netherlands, B.V. | Testing magnetic disk performance with a single slider simulating sliders of various disk drive systems |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0760481B2 (en) | 1995-06-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |