KR100416611B1 - A head and method for writing data and driving system for adapting it - Google Patents

Abstract

Disclosed is a head comprising a main write head for recording data on a recording medium, and a pre-write head positioned in advance of the main write head in the recording direction to pre-record the data to be recorded on the recording medium. have.

The disclosed head writes data to the pre-write head and then writes the same data back to the main write head. Therefore, when this is used as a magnetic head, the data recorded by the pre-write head can minimize HTS that may occur due to demagnetization and the like, and reduce the NLTS generated after writing. Minimize. Therefore, using the head according to the present invention, the overwrite characteristic can be greatly improved.

Description

A head and method for writing data and driving system for adapting it}

The present invention relates to a head and data recording method and a drive system employing the same, which can improve overwrite characteristics.

A device for writing data to a magnetic recording medium by a magnetic recording method such as a hard disk drive system and reading a signal recorded on the magnetic recording medium is provided with a magnetic head for performing a write and / or read operation. . The magnetic head is installed in a magnetic arm conveying apparatus of a swing arm drive type, and is moved to a desired track position on the magnetic recording medium in accordance with the rotation of the swing arm of the magnetic head conveying apparatus to perform a write or read operation.

Referring to FIG. 1, a hard disk drive system 1 generally includes a hard disk 2 rotatably installed on a base 8 and having predetermined information recorded thereon, and a magnetic head for recording and reading information. A magnetic head feeder for moving to a desired track position on the hard disk 2 is provided. Here, the hard disk 2 is divided into a recording area 2a in which information is recorded, and a parking area 2b prepared so that the magnetic head 6 is parked when the rotation of the hard disk 2 is stopped.

The magnetic head feeder includes a magnetic head assembly (3) mounted with a magnetic head and rotatably installed about a rotation shaft (7) provided on the base (8), and the magnetic head assembly (3) by electromagnetic force. The drive part 9 for rotating is provided.

The magnetic head assembly (3) includes a suspension (4) coupled to an end of an actuator arm (5) rotatably coupled to the pivotal shaft (7), and recording information on the hard disk (2). A magnetic head (not shown) for reading the information recorded in 2) is provided, and the magnetic head slider 6 is provided in the suspension 4.

The magnetic head slider 6 is biased toward the hard disk 2 by the suspension 4, and when the hard disk 2 starts to rotate, by the air dynamic pressure generated by the rotation of the hard disk 2, Flying with respect to the hard disk (2) (flying). At this time, the flying height of the magnetic head slider 6 while floating (Gap Flying Height) is due to the gram load of the suspension (4) and the air flow (air flow) according to the rotation of the hard disk (2) By lift and the like. Here, the flying height is provided on the tip side of the magnetic head slider 6 when the magnetic head slider 6 is floated with respect to the hard disk 2 during the rotation of the hard disk 2. And a gap between the surface of the hard disk 2. The gram load refers to the force exerted by the suspension 4. Higher gram loads correspond to more rigid suspensions.

2 and 3, a conventional magnetic head includes a write head 10 for writing data to a magnetic recording medium by a magnetic recording method, and a read head 17 for reading data written on the magnetic recording medium. ).

The write head 10 is a top pole 13 and a bottom pole 15 for forming a leakage magnetic flux with a magnetic recording medium, and a recording coil for forming a magnetic field for recording by an applied current. (14). Magnetic flux generated in the recording coil 14 is emitted through the gap g 'between the top pole 13 and the bottom pole 15.

The read head 17 is shielded so as not to be influenced by an external magnetic field other than the magnetic field by magnetic signals recorded on the magnetic recording medium by the shielding members 18 and 19.

As shown in FIG. 4, the magnetic recording medium stores data D1, D2, D3, and D4 represented in the magnetization direction and the magnetization length along the track 21. As shown in FIG. The direction of the arrow shown on the track 21 in FIG. 4 corresponds to the magnetization direction, and the length of the arrow corresponds to the magnetization length.

The direction of the magnetic fields 23a and 23b changes depending on the form in which the direction of the transition due to the change in the magnetization direction representing the data changes.

Therefore, the read head 17 detects the change in direction of the transition as a change in resistance and reads out information.

The lower graph in Fig. 4 shows a signal for recording the data D1, D2, D3, D4 shown above or a reconstruction signal for the data D1, D2, D3, D4.

However, in the conventional magnetic head as described above, when overwriting on data previously written on the magnetic recording medium, it is difficult to accurately write new data desired by the previously written data.

5 shows a transition shift when overwriting data on a magnetic recording medium with a conventional magnetic head. Here, an example in which new data is recorded in half periods of the old data, f1 denotes a frequency of previously written data, and f2 denotes a frequency of new data. Indicates.

Referring to FIG. 5, when the previously written data and the new data to be written are in the same direction (Easy), the data is written in the correct position, but in the opposite direction (Hard), the old data is written. Demagnetization of the part moves the position where the data is written. That is, as in FIG. 5, when the previously written data and the newly written data are in the same direction (Easy), the transition occurs exactly where desired, but when the opposite direction (Hard) is written slightly pushed.

Here, a phenomenon in which the write flux bubble is affected before being written by the direction of the data recorded at the previous position is called a hard transition shift (HTS). Since magnets do not stick to each other, when data is recorded in the same direction adjacent to each other, microscopic phenomenon occurs when the data is pushed after writing. This phenomenon is called NLTS (Non Linear Transition Shift). .

Increasing bit per inch (BPI) as the capacity of a magnetic recording medium, such as a hard disk, increases, means that adjacent signals are getting closer. Therefore, as the recording capacity of the magnetic recording medium increases, the influence of the transition shift during overwriting becomes more serious.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can improve the write performance during overwriting, thereby improving the head and data recording method of the improved structure that can cope with the demand for increasing the capacity of the recording medium. And a drive system employing the same.

1 is a plan view schematically showing the structure of a typical hard disk drive system,

2 is a view schematically showing the structure of a conventional magnetic head,

3 is a cross-sectional view taken along line III-III of FIG. 2;

4 is a view for explaining a principle of reading information by detecting a change in direction of a transition as a change in resistance with a read head;

5 is a diagram showing a transition shift when overwriting data on a magnetic recording medium with a conventional magnetic head;

6 is a view schematically showing the structure of a magnetic head according to a preferred embodiment of the present invention;

FIG. 7 is a sectional view taken along line VII-VII of FIG. 6;

8A is a graph showing a result of spectrum analysis of a signal recorded on a magnetic recording medium when first overwriting a magnetic recording medium in which existing data remains;

FIG. 8B is a spectrum analysis result of a signal recorded on the magnetic recording medium when the same data as the data of the first overwriting on the first overwritten magnetic recording medium is secondly overwritten at the same position as shown in FIG. 8A. Shows the graph.

<Description of the symbols for the main parts of the drawings>

30 ... Magnetic recording medium 40 ... Main writing head

50 ... free write head 60 ... read head

A head according to the present invention for achieving the above object includes a main write head for recording data on a recording medium; And a pre-write head positioned ahead of the main write head in a recording direction, for pre-recording data to be recorded on a recording medium.

Preferably, the main write head and the pre-write head are tuned to write the same data at the same position.

The recording medium may be a magnetic recording medium, and the main write head and the pre-write head may be magnetic recording heads.

In this case, it is preferable to further include a read head for reading a magnetic signal recorded on the magnetic recording medium.

Further, it is preferable that the read head is positioned in the writing direction ahead of the main write head, and the pre-write head is located between the main write head and the read head.

A data recording method according to the present invention for achieving the above object comprises the steps of: pre-recording data to be recorded on a recording medium with a pre-write head positioned ahead of the main write head in the recording direction; And re-writing the same data as that by the pre-write head as the main write head following the pre-write head at the same position.

In this case, the main write head and the pre-write head are preferably tuned to write the same data at the same position.

The recording medium may be a magnetic recording medium, and the main write head and the pre-write head may be magnetic recording heads.

In order to achieve the above object, the present invention provides a drive system including a head for recording information on a recording medium and / or reading information recorded on the recording medium, wherein the head is configured to record data on the recording medium. Main write head for; And a pre-write head positioned ahead of the main write head in a recording direction, for pre-recording data to be recorded on a recording medium.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

6 is a view schematically showing the structure of a magnetic head according to a preferred embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along line X-ray of FIG.

The magnetic head according to the embodiment of the present invention can be applied to a magnetic disk drive system such as a hard disk drive system as shown in FIG. 1. Hereinafter, an example in which a head according to the present invention is applied as a magnetic head to a magnetic head assembly of a hard disk drive system as shown in FIG. 1 will be described.

6 and 7, a magnetic head according to an embodiment of the present invention includes a main write head 40 for recording data on a magnetic recording medium 30, and the main head in a recording direction. It includes a pre-write head (50), which is positioned before the write head (40), to pre-write the data to be recorded on the magnetic recording medium (30).

The main write head 40 may include a top pole 41 and a bottom pole 45 for forming leakage magnetic flux to the magnetic recording medium 30, and a coil for recording to form a magnetic field for recording by an applied current. 43).

Similarly, the pre-write head 50 is a top pole 51 and a bottom pole 55 for forming a leakage magnetic flux to the magnetic recording medium 30, and a recording for forming a magnetic field for recording by the applied current. Coil 53.

The main write head 40 and the pre-write head 50 each have a magnetic flux generated in the recording coils 43 and 53 for the top poles 41, 51, and bottom poles 45, 55. Through the gap g1 (g2).

The direction of the magnetic flux is determined in accordance with the direction of the current applied to the recording coils 43 and 53. Therefore, the recording of the data using the main write head 40 and the pre-write head 50, the magnetic flux emitted through the gap (g1) (g2) to the data storage portion 31 on the magnetic recording medium (30): Magnetic recording layer of the magnetic recording medium) to cause magnetization in a desired direction. Here, a material that can be magnetized by an external magnetic field is coated on the magnetic recording medium 30. Therefore, the magnetization direction and the magnetization length of the specific region of the magnetic recording medium 30 are determined by the magnetic flux forms from the main write head 40 and the pre-write head 50.

In the magnetic head according to the present invention, the main write head 40 and the pre-write head 50 are synchronized with each other to perform a write operation, and then write the specific data to the pre-write head 50 and then follow the main write head 40. In the same part, the same data is recorded.

When writing to the main write head 40 and the pre-write head 50 in this manner, the main write head 40 and the pre-write head 50 have the write gap distance (write) in order to synchronize and record at the same position. Corresponding to gap distance: d), it should be able to record with correct write time difference

Since there is a write gap distance d between the main write head 40 and the pre-write head 50, the main write head 40 and the pre-write head 50 are synchronized by writing data with an accurate write time difference. In order to do this, the write time difference corresponding to the write gap distance d between the main write head 40 and the pre-write head 50 must be accurately known.

The write time difference for the synchronization between the main write head 40 and the pre-write head 50 is the main write head 40 and the pre-write head 50 during the process test after the drive assembly employing the magnetic head according to the present invention. It is possible to measure by simultaneously reading a single pulse on a specific track of a magnetic recording medium (a spare track of the magnetic recording medium or a track introduced separately for testing on the magnetic recording medium) and reading it with the read head 60. have. The measured value is a value corresponding to the rotational speed and the write gap distance (d) of the magnetic recording medium. When the same data is to be recorded at the same position by the main write head 40 and the pre-write head 50, the main data is recorded. This is a time difference in which the same data should be generated in the write head 40 and the pre-write head 50. This value may be stored in a memory, and the drive write operation may be referred to to match the synchronization between the main write head 40 and the prewrite head 50.

On the other hand, the magnetic head according to an embodiment of the present invention preferably further includes a read head 60 for reading the magnetic signal recorded on the magnetic recording medium 30. Preferably, the read head 60 includes a magnetoresistive head such as a giant magnetoresistive head GMR. The read head 60 is preferably shielded from the external magnetic field other than the magnetic field by the magnetic signal recorded on the magnetic recording medium 30 by the shielding member 61.

When the read head 60 is positioned ahead of the main write head 40 in the write direction, the prewrite head 50 is located between the main write head 40 and the read head 60. As described above with reference to FIG. 4, the read head 60 detects a change in direction of a transition as a resistance change in an area of the magnetic recording medium where a transition is generated and reads information. Serve

The magnetic head according to the present invention as described above operates as follows.

When data is recorded on the target track of the magnetic recording medium 30, first, data to be written to the main write head 40 by the pre-write head 50 is overwritten on existing data existing in the target track.

As described above, the target track overwritten by the prewrite head 50 is substantially erased, and at the same time, the magnetized state is optimal for recording the final data into the main write head 40.

Then, when the same data as that by the pre-write head 50 starts to be written from the same position to the main write head 40 following the pre-write head 50, the desired optimal data is recorded.

When data is written to the target track by the pre-write head 50, although the transition shift as described with reference to FIG. 5 occurs slightly, the target data is recorded again by the target data by the main write head 40 on the target track. Optimal data can be recorded.

FIG. 8A shows a spectrum analysis result (using a spectrum analyzer) of a signal recorded on the magnetic recording medium when the existing magnetic recording medium in which the existing data remains is overwritten first. FIG. 8B is a spectrum analysis result of a signal recorded on the magnetic recording medium when the same data as the data of the first overwriting on the first overwritten magnetic recording medium is secondly overwritten at the same position as shown in FIG. 8A. Shows.

FIG. 8A illustrates a case in which 80 Mflux / sec data is first overwritten on a magnetic recording medium having 20 Mflux / sec data remaining, and FIG. 8B shows 80 Mflux / sec data again on the magnetic recording medium. Second overwrite. Here, 1 flux / sec = 0.5 Hz.

As can be seen in FIG. 8A, when new data is overwritten on a magnetic recording medium on which existing data remains, a transition occurs due to reaction force caused by the existing data, thereby causing components and unnecessary data by the existing data. Side band components will be present.

However, as can be seen in FIG. 8B, when the data to be written is overwritten twice, both components and sideband components due to the existing data disappear.

Therefore, according to the magnetic head according to the present invention, since the same data is overwritten, noise due to the existing data is reduced and the overwrite performance is improved.

In addition, when overwriting only once, the data to be newly reduced according to the transition type of the existing data is affected, but when the data is overwritten twice, the same data is written, so that the NLTS may be improved.

In addition, the magnetic head according to the present invention synchronizes the two write heads to perform a write operation at the same time, thereby obtaining a fast writing speed compared to the overwrite performance.

In the above, the present invention has been described and illustrated as being applied to a magnetic head for performing magnetic writing and / or reading and a magnetic disk drive system such as a hard disk drive system employing the same, but the present invention is not necessarily limited thereto. Various modifications and applications are possible. That is, the technique of the present invention can be applied to a head of a recording method other than the magnetic recording method and a disk drive system employing the same.

The magnetic head according to the present invention as described above has a pre-write head that precedes the main write head in the writing direction, synchronizes the main write head and the pre-write head, writes data to the pre-write head, and then goes to the main write head. Write the same data again.

According to the magnetic head according to the present invention, the data recorded by the pre-write head can minimize HTS that may occur due to demagnetization, reduce NLTS generated after writing, and Minimize noise caused by Therefore, using the magnetic head according to the present invention, the overwrite characteristic can be greatly improved.

Claims (10)

A main write head for recording data on the recording medium; And a pre-write head positioned ahead of the main write head in a recording direction, for pre-recording data to be recorded on a recording medium. The head of claim 1, wherein the main write head and the pre-write head are tuned to write the same data at the same position. The head according to claim 1 or 2, wherein the recording medium is a magnetic recording medium, and the main write head and pre-write head are magnetic recording heads. 4. The head according to claim 3, further comprising a read head for reading a magnetic signal recorded on the magnetic recording medium. The magnetic head as claimed in claim 4, wherein the read head is positioned ahead of the main write head in a write direction, and the pre-write head is located between the main write head and the read head. Pre-recording data to be recorded on the recording medium with the pre-write head positioned ahead of the main write head in the recording direction; And re-writing the same data as that caused by the pre-write head into the main write head following the pre-write head at the same position. 7. The recording method as claimed in claim 6, wherein the main write head and the pre-write head are tuned to write the same data at the same position. 8. A recording method according to claim 6 or 7, wherein the recording medium is a magnetic recording medium, and the main write head and pre-write head are magnetic recording heads. A drive system comprising a head for recording information on a recording medium and / or reading information recorded on the recording medium, The head is A main write head for recording data on the recording medium; And a pre-write head positioned ahead of the main write head in a recording direction, for pre-recording data to be recorded on a recording medium. 10. The drive system according to claim 9, wherein the recording medium is a magnetic recording medium, and the main write head and pre-write head are magnetic recording heads.