JPH0760481B2 - Inspection method of magnetic recording medium - Google Patents
Inspection method of magnetic recording mediumInfo
- Publication number
- JPH0760481B2 JPH0760481B2 JP62256941A JP25694187A JPH0760481B2 JP H0760481 B2 JPH0760481 B2 JP H0760481B2 JP 62256941 A JP62256941 A JP 62256941A JP 25694187 A JP25694187 A JP 25694187A JP H0760481 B2 JPH0760481 B2 JP H0760481B2
- Authority
- JP
- Japan
- Prior art keywords
- recording medium
- magnetic recording
- write current
- value
- reproduction output
- 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 - Fee Related
Links
Landscapes
- Recording Or Reproducing By Magnetic Means (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、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。The present invention relates to a method for inspecting 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。The magnetic recording medium can also be referred to as a heart component of a hard disk device used as an external storage device of a computer. The recording performance is inspected by dividing the measurement radius into two or four, writing by the head with a write current set to a predetermined value for each radius, and then reading by the head to obtain a reproduction output. Was there.
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, in the inspection method as described above, head variations,
Alternatively, since it is not possible to respond to changes over time due to head deformation and the like, the magnetic fields applied to the medium are not the same even with the same write current, causing variations in electromagnetic conversion characteristics and signal quality. However, there was a drawback in that the recording performance of could not be evaluated correctly.
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 object of the present invention is to be able to perform recording by applying a desired magnetic field to a magnetic recording medium without being affected by variations in quality of a used head or aging except for the above-mentioned drawbacks,
It is an object of the present invention to provide a method for inspecting a magnetic recording medium, which 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
ドにより書き込み電流を変化させて前記媒体の再生出力
を測定することにより前記書き込み電流に対する再生出
力の飽和特性を求め、この飽和特性に基づいて前記再生
出力の最大値の90％に相当する再生出力値に対応する書
き込み電流値を求め、この電流値を所定倍することによ
り再生出力の飽和値に対応する書き込み電流値を求め、
この電流値の書き込み電流により前記媒体の記録性能を
測定することを特徴としている。In order to achieve the above-mentioned object, the method of the present invention comprises measuring the reproduction output of the medium by changing the write current with a head levitated above a predetermined radial position of the magnetic recording medium to be inspected. The saturation characteristic of the reproduction output with respect to the write current is obtained, and the write current value corresponding to the reproduction output value corresponding to 90% of the maximum value of the reproduction output is obtained based on this saturation characteristic, and this current value is multiplied by a predetermined value. Obtain the write current value corresponding to the saturation value of the playback output,
The recording performance of the medium is measured by the write current of this current value.
また、上記所定倍を1.5倍とするのが好ましい。Further, it is preferable that the predetermined multiple is 1.5 times.
ヘッドによる磁界の印加によっ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、その飽和部分は再生出
力の書き込み電流に対する変化率が小さく、飽和値にに
対応する書き込み電流値が確定しにくいので、再生出力
の書き込み電流に対する変化率が十分大きな再生出力の
最大値の90％に相当する部分でそれに対応する書き込み
電流値を求め、この電流値を所定倍することにより再生
出力の飽和値に対応する書き込み電流値を求めることに
より、媒体に印加する磁界を一定にしている。通常再生
出力の最大値の90％の再生出力値に対応する書き込み電
流値の1.5倍を用いて書き込みを行うと第２図のＨ′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。The magnetic field applied by the head causes the magnetization of the magnetic recording medium to have a hysteresis curve as shown in FIG. When the write current is increased, the playback output saturates, but in the saturated part, the rate of change of the playback output with respect to the write current is small, and it is difficult to determine the write current value corresponding to the saturation value. Is a sufficiently large portion corresponding to 90% of the maximum value of the reproduction output, the writing current value corresponding to it is obtained, and by multiplying this current value by a predetermined value, the writing current value corresponding to the saturation value of the reproduction output is obtained. The magnetic field applied to the medium is constant. When writing is performed using 1.5 times the write current value corresponding to the reproduction output value of 90% of the maximum value of the normal reproduction output, a magnetic field corresponding to H'in FIG. 2 is generated in the magnetic recording medium, and the applied magnetic field is generated. Is an appropriate value for magnetic recording. Therefore, the recording characteristics under proper conditions for use 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１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
は電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。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を上下に動かして浮上量を一定に
合わせる。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、線11,12,13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
込み電流値をとった場合、磁気記録媒体に印加される磁
界は、第２図に示したＨ′であることが確かめられた。
このＨ′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。例えば半径47.5mmの磁気記録媒体の
半径45mmの最外周，半径21.5mmの最内周およびその中間
の33.3mmの円周部で測定を行う。FIG. 3 shows an inspection apparatus used in one embodiment of the present invention.
A magnetic recording medium 1 to be measured is mounted on a spindle 2 of this apparatus, and a head arm 4 and a head 3 mounted on a Z-axis moving stage 5 are mounted on the surface of the medium. Measuring instrument 7
Is an electric circuit for inspecting electromagnetic conversion characteristics and signal quality, and is connected to a printer 8 for recording the measurement result. In such a structure, the head 3 floats by rotating the spindle 2 at a high speed. At this time, the flying height of the head is detected by the interference pattern of light, and the head arm 4 of the moving stage 5 is moved up and down to make the flying height constant. Next, the head 3 is moved to the measurement position by the carriage 6, and the saturation characteristic of the reproduction output with respect to the write current by the head 3 is measured at that position. FIG. 1 is a graph showing the saturation characteristics. As shown in FIG. 1, even if the same magnetic recording medium is measured due to variations in the head 3, different results are obtained as indicated by lines 11, 12, and 13, but the reproduction output of the saturation characteristic obtained from this saturation curve. 90% of maximum
It was confirmed that the magnetic field applied to the magnetic recording medium was H'shown in FIG. 2 when the write current value I'which is 1.5 times the write output value I'corresponding to the reproduction output was taken.
The magnetic field of H'is an optimum state at the time of recording on the magnetic recording medium, and the electromagnetic conversion characteristics and the signal quality can be inspected under the condition that is not related to the variation of the head. By performing such an inspection while moving the head 3 in the radial direction, the entire surface of the magnetic recording medium 1 can be inspected. However, in view of inspection efficiency, the inspection may be performed only at a plurality of radial positions. For example, a magnetic recording medium with a radius of 47.5 mm is measured at the outermost periphery with a radius of 45 mm, the innermost periphery with a radius of 21.5 mm, and the circumference of 33.3 mm in between.
媒体にＨ′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図からわ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、磁気記録媒体の保磁力の推定が容易にでき
る。The write current required to apply the magnetic field of H'to the medium can be obtained from the ratio of the write current to the reproduction output of 100% in FIG. 1, but such a write current value can be seen from FIG. Since it is difficult to determine the value, it is desirable to use the value of 90%. But other methods, for example 80
The value for% playback output may be multiplied by the appropriate multiple.
The coercive force of the magnetic recording medium can be easily estimated from the write current value obtained from the saturation characteristics shown in FIG.
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。
同時に飽和特性より得られた書き込み電流値により、磁
気記録媒体の保磁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。According to the present invention, it is possible to set the write current that makes the magnetic field applied to the magnetic recording medium constant by using the saturation characteristic of the reproduction output due to the write current, reduce the influence of head variation and aging, and An inspection method that can know the highly reliable recording performance of the recording medium has been obtained.
At the same time, the write current value obtained from the saturation characteristics facilitates the estimation of the coercive force of the magnetic recording medium, so that data useful for designing the magnetic recording device can be obtained.
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−Ｈ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:スピンドル、3:ヘッド、4:ヘッドア
ーム、7:測定器。FIG. 1 is a diagram showing a saturation characteristic of reproduction output by a write current to a magnetic recording medium used in one embodiment of the present invention, FIG.
FIG. 3 is a BH history curve diagram of the magnetic recording medium, and FIG. 3 is a front view of a main part showing a measuring apparatus for one embodiment of the present invention. 1: magnetic recording medium, 2: spindle, 3: head, 4: head arm, 7: measuring instrument.
Claims (2)
上に浮上させたヘッドにより書き込み電流を変化させて
前記媒体の再生出力を測定することにより前記書き込み
電流に対する再生出力の飽和特性を求め、この飽和特性
に基づいて前記再生出力の最大値の90％に相当する再生
出力値に対応する書き込み電流値を求め、この電流値を
所定倍することにより再生出力の飽和値に対応する書き
込み電流値を求め、この電流値の書き込み電流により前
記媒体の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。1. A saturation characteristic of a reproduction output with respect to the write current is obtained by measuring a reproduction output of the medium by changing a write current with a head levitated above a predetermined radial position of a magnetic recording medium to be inspected. , A write current value corresponding to a reproduction output value corresponding to 90% of the maximum value of the reproduction output is obtained based on the saturation characteristic, and the write current corresponding to the saturation value of the reproduction output is obtained by multiplying this current value by a predetermined value. A method for inspecting a magnetic recording medium, wherein a value is obtained, and the recording performance of the medium is measured by the write current of this current value.
て、前記所定倍が1.5倍であることを特徴とする磁気記
録媒体の検査方法。2. A method of inspecting a magnetic recording medium according to claim 1, wherein the predetermined multiple is 1.5 times.
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 JPH0198101A (en) | 1989-04-17 |
| JPH0760481B2 true 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) |
Families Citing this family (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 |
Family Cites Families (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 |
| JPH0644327B2 (en) * | 1985-09-12 | 1994-06-08 | 三菱電機株式会社 | Magnetic recording / reproducing device |
-
1987
- 1987-10-12 JP JP62256941A patent/JPH0760481B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0198101A (en) | 1989-04-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |