JPH01211381A - Head positioning information writing device - Google Patents

Abstract

PURPOSE:To improve productivity by adding a disk surface defect detection circuit and an absolute track position correction circuit to a head position information writing device. CONSTITUTION:A mirror 6 for measuring a distance is attached near a position information write head 3 so as to enable laser control by the position information writing device. Under this state, positioning by a laser is executed for a defect-free specified track and the defect of a disk is detected by it own data head 4 in the disk surface detection circuit 9. When the defect is recognized, the absolute position of the defect-free specified track is changed by a position correction indication circuit 10 and the same operation is repeated. Thus, the defect of the defect-free specified track can be removed and the defect of the disk which can occur in course of being produced can be evaded as the demand of a system specially without raising the cost of the writing device. As the result of that, the productivity can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a head positioning information writing device, and in particular,
The present invention relates to a production device suitable for improving the productivity of magnetic disk devices.

[Conventional technology]

Conventionally, it has been used as a means to avoid defective tracks in designated defect-free tracks of magnetic disk drives.
As shown in Japanese Patent No. 77, there is known a means for logically avoiding this problem by adding a control circuit within the magnetic disk device.

[Problem to be solved by the invention]

What are the magnetic disks used in magnetic disk devices?

Are defects created on the disk surface during the manufacturing process?
Therefore, it is common to use these defects as areas that are allowed by the device but are prohibited from use. In recent years, as recording density has improved, the number of defects has also increased. On the other hand, there is still a demand for defect-free designated tracks on a magnetic disk surface in a system. For one disk device.

A plurality of disks are used, and after they are superimposed and assembled, the - side is used as the head positioning information writing side, and the remaining side is used as the data storage side. Now, what about this production process? The reasons for designating defect-free tracks on the data storage surface are: (1) First, position information is written (a disk with a defective Tc is selected and used on this surface in advance), and as a result, the data storage surface is If it matches the designated defect-free track,
JP is redone from the first disc overlapping & ze process once again, and the same process is repeated again.

(2) It is shown in Jikai No. 61-156577 'B
c.

There is a first method in which the position information is stored and if it matches a designated defect-free track on the data storage surface, the track position is logically changed using a circuit within the device.

However, with these methods, productivity is poor in the case of (1) above, and F1 productivity is influenced by the distribution probability of defects. In particular, since it is extracted for the first time in the post-process, recombination of the device is inevitable.

In the case of l fc (2), since a dedicated circuit is added to each device, there are problems such as not being able to maintain compatibility between control circuits and increasing the cost of the device.The purpose of the present invention is to: To solve these problems, 1) At the time t when position information is written, the presence or absence of a defect on the defect-free track on the data storage surface is detected, and if there is a defect, the absolute position of the position information is automatically changed, and the position The purpose is to improve productivity by rewriting information.

[Means to solve the problem]

The above object is achieved by adding a disk surface defect detection circuit and an absolute track position correction circuit to the head position information writing device. How to write location information.

Since high accuracy is required, a laser source is used for positioning the write head, the resolution is set to about 0.2 μm, and the correction width is variable by about 5 tracks of the track pitch used.

There are several known technologies for detecting defects on the disk surface, but this device detects defects by combining a missing detection method that detects a decrease in successive signals and a phase margin method using five phases. improve rate. Basically, the operation of this device is to first position the position information writing head to the absolute position of the designated defect-free track using the laser source, and while maintaining that state, detect defects on the data storage surface. If the defect exists, the operation is repeated while correcting the absolute position, and the absolute position k is changed to avoid the defect on the designated defect-free track. Furthermore, the fluctuation of the absolute position is
This does not pose any problem in actual use.

[Effect]

Head positioning information in a magnetic disk drive The relative position of the read head and the write/read head on the data storage surface is
Since these are unique positional relationships that are determined when they are installed, it is necessary to write positional information and detect defects on the data surface from the head f of the own device. Near the position information writing head,
Attach a distance sub-length mirror to enable laser control using the position information writing device? Ku. In this state, use the laser to position the designated defect-free track.
Disk defects are detected using the chome data head. Once the defect has been discovered, by changing the absolute position of the defect-free designated track and repeating the same operation, it becomes possible to eliminate defects on the defect-free designated track, which especially increases the cost of the equipment. Therefore, disk defects that may occur during production can be avoided as required by the system, and productivity can be improved.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 shows an example of the basic configuration of a head positioning information writing device. 1 is a magnetic disk device, which includes a magnetic disk 22, a position information write/read head 6, a data read/write head 4.
Magnetic head group t-1f) Cow spear to be moved as kR body 14. A voice coil motor 15 for driving the carriage at a predetermined distance t'E. It consists of 5 is the carriage position.

6 is a mirror for serving as a sub-length in the laser sub-length circuit. 7
8 is a position control circuit, 8 is a position information write/read circuit, 9 is a disk surface defect detection circuit, and IQ is a 1 position correction circuit.

The circuits added according to the present invention are 9 and 10.

The operation will be explained below. The carriage 14 that moves the head group is controlled by one position control circuit 7. Voice coil motor 15. Mirror 5. The position is controlled by a closed loop circuit formed by the laser length measuring circuit 6. The track position of the data storage surface 2-2 always moves in the same relative position as the track position written on the 1-position information writing surface 2-1. Now, take the position of the defect-free designated track in advance using the 1 position control circuit 7V.
c By manual effort, the data write/read head 4 moves by the carriage 14Vr1 and is positioned on the absolute track position of the defect-free designated trunk. Here, the presence or absence of a defect on the data storage surface is detected by the disk surface defect detection circuit 9 based on the determination criteria shown in FIG. 3 when the data write/read head 4 actually writes/reads. Now, when the presence of a defect shown in FIG. 3 (α) is detected on the defect-free designated track, the signal is returned to the position correction designation circuit 10 from 9, and as a result, the position is corrected to the position control circuit 7. A signal is applied, and based on this, the magnetic head group is positioned again, and detection of the presence or absence of defects is repeated until the read waveform shown in FIG. 3 (4) is obtained. As shown in FIG. 2, if a defect 12 exists on the designated defect-free track 11, by repeating the above-mentioned operation, the absolute track position is automatically changed by using the defect-free track position 13 instead of the defect-free designated track 11. Based on this correction value, the first place dust information is written while controlling the position of the position information writing head 3.

Incidentally, the change in the absolute track position is on the order of a real number + μm, and there is no problem in actual use of the device. According to this embodiment, defects on designated defect-free tracks are avoided by changing the absolute track position when writing position information, thereby suppressing cost increases due to unnecessary equipment recombination and improving productivity. It can be measured.

〔Effect of the invention〕

According to the present invention, it is possible to improve productivity without increasing the cost of the equipment due to the increase in disk surface defects during the manufacturing process due to the increase in recording density and the contradictory requirement for defect-free designated tracks, thereby improving efficiency. This is highly effective in reducing total costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG.
6 is a data storage surface track position diagram, and FIG. 6 is a data storage surface read waveform diagram. 1...Magnetic disk device. 2...Magnetic disk, 2-1...Position information 1°
Komimen. 2-2 Data storage surface. 3...Position information writing/reading head. 4...Data write/read head. 5...Mirror, 6...Laser length measurement circuit. 7...Position control circuit. b...Position information writing/reading circuit. 9...Disk surface defect detection circuit. 10...Position correction instruction circuit. 11...Defect track, 12...Defect position [. 13...Alternative trunk, 14...Nakayaritsuji. 15...Voice coil motor. 111/ Akira 2nd item difficulty (a) (b) Missing A white product and level 1

Claims (1)

[Claims] A head positioning information writing device for a magnetic disk device with a laser-based head positioning control mechanism has a function of writing head positioning information on the disk surface as well as a defect detection function on the data storage disk surface. death,
A head positioning information writing device characterized in that an absolute writing position can be moved and written so that a designated defect-free track on a data storage surface does not coincide with a track when writing head positioning information.