JP2002184138A - Disk unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk unit in which signals stored on a disk surface are converted into correct head position information using position sensitivity correction values. SOLUTION: Two phase information in which phases are varied by a 1/3 cylinder pitch is recorded on the surface of a disk medium. When position sensitivity correction values are measured by a position sensitivity measuring section, on-track control is applied to cross points 102 and 104 of two phase servo signals N and Q and the values at the points 102 and 104 are measured to obtain a position sensitivity correction value. The position sensitivity measuring section obtains the measured value at the position 102 where the cross point is located at a plus side and the measured value at the position 104 that is separated two tracks and the cross point becomes minus and computes a position sensitivity correction value by obtaining an average value of the absolute values of the two measured values.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved compact disk drive for performing position sensitivity measurement processing and generating sector pulses in consideration of encoding loss at the time of reading and decoding loss at the time of reading.

[0002]

2. Description of the Related Art In recent years, the track pitch of a magnetic disk device has been reduced due to the miniaturization and the increase in capacity, and an improvement in on-track accuracy has been required. In addition, by adopting an MR head with a narrow core width as a read head, a core displacement between the write head and the read head is indispensable, as opposed to a write head using an inductive head. The switching position may be the on-track position.

[0003] For this reason, conventionally, at 1/2 track pitch, 2
What changed the phase of the phase servo pattern to 1/3
Two-phase servo information that changes the phase at the track pitch is used.

[0004]

However, the measurement of the position sensitivity correction value in the conventional disk drive requires two measurements.
The cross points of the phase servo signals N and Q may be measured. However, since the servo signals N and Q are discretely obtained at predetermined sampling periods, the cross points cannot be directly measured. Therefore,
Two-phase servo signals N and Q obtained when constant velocity seek is performed
Since the value of the cross point is determined by linear interpolation from the values before and after crossing the cross point, an error occurs.

In a two-phase servo signal for changing the phase at 1/3 track pitch by reducing the track pitch,
While moving one track, there are two cross points,
Since the density of cross points was doubled compared to the case of track pitch, it took too much time to measure the position sensitivity correction value, and there was a problem that improvement in measurement accuracy could not be expected due to linear interpolation. .

Further, conventionally, in order to reduce the size and capacity of the disk device, the size of the disk has been reduced and the capacity of the disk has been increased by high-density recording.
The read and write signal processing systems have also been enhanced in function by adopting a partial response maximum likelihood method (PRML) or the like.

[0007] With such advanced functions of the signal processing system,
There is a large time loss in encoding and decoding which has not been a problem in the conventional 1-7 RLL or the like. For example, in the case of 1-7 RLL, the loss is only about 5 bits, but in the signal processing by the partial response maximum likelihood method, for example, there are about 10 times as much as 44 bits, and a gap area corresponding to that is required. There is a problem that the format efficiency is reduced.

Particularly, in the conventional format in which loss of encoding and decoding is taken into consideration, the encoding loss which increases the time from the end of inputting NRZ data during the write operation to the end of writing to the disk medium, and the read operation A gap area corresponding to a loss that is obtained by adding both decoding loss from the time when a read signal is obtained to the time when NRZ data is actually demodulated and output is provided.

An object of the present invention is to provide a disk drive which improves the on-track accuracy by improving the measurement time and accuracy of the position sensitivity correction value even if the track pitch of the two-phase servo information is narrowed.

Another object of the present invention is to provide a disk drive capable of reducing the required gap area and increasing the format efficiency even when the encoding loss during a write operation and the decode loss during a read operation increase. provide.

[0011]

FIG. 1 is a diagram illustrating the principle of the present invention.

According to the present invention, a two-phase servo signal N, detected from a read signal of two-phase servo information recorded on a disk surface,
A disk device for converting Q into correct head position information using a position sensitivity correction value measured in advance.

The present invention relates to such a disk drive.
As shown in FIG. 1B, 1 /
Two-phase servo information is recorded so that the phase changes at three cylinder pitches. When a position sensitivity correction value is measured by the position sensitivity measurement unit, the two-phase servo signal N,
On-track control is performed on the Q cross points 102 and 104, and the position sensitivity correction value is obtained by measuring the values of the cross points 102 and 104.

Here, the position sensitivity measuring section obtains the measured value at the position 102 where the cross point is on the plus side and the measured value at the position 104 where the cross point separated by two tracks is negative, and calculates the absolute value of the two measured values. The average value is used as the position sensitivity correction value. Thereby, the vertical asymmetry of the waveform read by the MR head can be reduced.

The position sensitivity measuring section calculates a correction coefficient for correcting the measured value of the cross point to a theoretical value as a position sensitivity correction value.

Further, the position sensitivity measuring section divides the recording area of the disk medium into a plurality of zones, measures and stores a position sensitivity correction value for each zone boundary position, and controls the head position when controlling the head position. The position sensitivity correction value at the current position is calculated by linear interpolation from the position sensitivity correction values at the two zone boundary positions of the located zone.

Further, according to the present invention, a track of a disk medium is divided into a plurality of sectors, a sector mark is recorded at a head position of each sector, and a sector obtained by reading the sector mark during a read operation or a write operation of the disk medium. In a disk device that generates a write gate signal or a read gate signal based on a pulse, a decrease in format efficiency due to encoding loss and decoding loss is improved.

For this reason, in the disk device of the present invention, a gap area for a time corresponding to the encoding loss due to the write operation is provided at the last position of each sector of the disk medium, and the write gate generating unit converts the sector pulse into a sector pulse during the write operation. Synchronously, a write gate signal is generated, and the write gate signal is stopped by the detection signal of the gap region. The read gate generator generates a read gate signal in synchronization with a sector pulse delayed by a time corresponding to a decode loss due to the read operation during a read operation, and changes a gap area detection signal to a time corresponding to the decode loss. Stop by a signal delayed by a minute.

For this reason, the cap area of each sector only needs to be an area corresponding to the encoding loss at the time of the write operation, and the format efficiency is higher than that in the conventional case where a gap area corresponding to both the encoding loss and the decoding loss is provided. Can be improved, and the disk capacity can be increased.

The encoding loss and the decoding loss are as follows:
Since it differs depending on the cylinder position, each of the gap area corresponding to the time corresponding to the encoding loss and the delay time corresponding to the decoding loss is set to a value corresponding to the cylinder position of the head, for example, a value determined for each zone.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Table of Contents> 1. Overall structure 2. FPC mounting structure 3. RAM storage of offset correction data 4. Measurement of position sensitivity correction value Encoding / decoding loss Overall Structure FIG. 2 is a block diagram of the overall circuit configuration of the disk drive of the present invention. The disk drive 10, which is a disk device of the present invention, includes a control unit 12 and an enclosure 14. The enclosure 14 is provided with a disk 18 as a storage medium rotated by a spindle motor 16.

In the present invention, for example, two 2.5 inch magnetic disks are used. The enclosure 14 is provided with a voice coil motor (hereinafter, referred to as “VCM”) 20 for driving a head actuator, so that the head 22 can be positioned with respect to the data surface of the disk 18.

In this embodiment, the disk 18 is 2
Since the number of data is four, the number of data surfaces is four, and four heads 22 are used. Further, the head 14 is provided in the enclosure 14.
C27 is provided to perform read / write with respect to the head 22 and the control unit 12, read of servo information, head switching, and the like.

The control unit 12 has an MCU 24
Is provided. The MCU 24 incorporates a ROM 62a and a RAM 64a as shown in the figure, in addition to the CPU. The ROM 62a and the ROM 64a may be built in the MCU 24 or may be provided externally. For the MCU 24, an oscillator 26 for oscillating a predetermined clock, a logic IC 2 for generating a clock necessary for various controls based on the clock from the oscillator 26
8, a program memory 30 as an external ROM, a servo controller 32 for controlling the spindle motor 16 and the VCM 20 of the enclosure 14, a host system 40
A hard disk controller 34 for transferring various commands and data necessary for input / output between the controller and the buffer memory 36, and a read / write unit 38 for reading / writing data from / to the disk 18 are provided.

In addition to the above, the disk drive 10 of the present invention is provided with a shock sensor 41, and a detection signal of the shock sensor 41 is processed by a sensor IC 42 and given to the MCU 24. For example, a piezoelectric element is used as the shock sensor 41. When the acceleration in a certain direction due to an external shock exceeds a specified value by the sensor IC 42, a shock detection signal is output to the MCU 24. This write operation is forcibly terminated.

The piezoelectric element used as the shock sensor 41 has directionality. In this embodiment, the piezoelectric element is arranged so as to be able to detect an impact in the direction of rotation of the head 12 by the head actuator, that is, in the direction across the tracks of the disk 18. are doing.

Further, a console 43 can be provided outside the disk drive 10 as necessary, so that input / output to / from the MCU 24 required for starting up the apparatus or for maintenance can be performed.

FIG. 3 shows the internal structure of the enclosure 14 in the disk drive 10 of FIG. A disk 18 is provided on a base 21 of the enclosure by a spindle motor, and is rotated at a predetermined speed. Disc 1
8, the actuator 44 is provided at the corner of the base 21.
Is installed, the actuator 44 is rotated by the VCM 20 installed at the rear, and the head 22 at the tip is
8 so that positioning movement is possible in the radial direction.

Near the actuator 44, the head I
A base-side FPC 48 on which C23 is mounted is installed. FPC band 4 for read / write from base side FPC48
6 is pulled out and supported and fixed to the side surface of the actuator 44 on the head 22 side.

FIG. 4 is a sectional view taken along the line AA of FIG. An actuator 44 is rotatably mounted on the base 21,
The VCM 20 is installed at the rear. The tip of the actuator 44 is divided into three head arms, and the head 22 is installed at the tip of the head arm. Two disks 18 are connected to the rotating part of the spindle motor 16,
Four heads 22 for the data surfaces on both sides of the disk 18
Are arranged relative to each other. A cover 2 is provided on the upper part of the base 21.
3 is mounted, and the control unit 1 shown in FIG.
2 is mounted. 2. FPC Mounting Structure FIG. 5 shows the actuator 44 provided in the enclosure of FIG. From the base side FPC 48, the read / write FPC band 46
Is pulled out, is pinched by the retainer 45 on the side surface of the rotation shaft of the actuator 44, and the distal end portion extracted from the retainer 45 is connected to the FPC connection portion 5 of the head arm 60.
0, a relay FPC mounted on the head 22 side
Are connected by superposition.

FIG. 6 shows the FPC of the actuator 44 shown in FIG.
The retainer 45 is fixed to the side surface of the actuator 44 by a screw 54. By fixing the retainer 45, the tip of the read / write FPC band 46 and the end of the relay FPC 52 mounted on the head 22 side are overlapped and electrically and mechanically fixed in the FPC connection portion 50. .

FIG. 7 is an enlarged view of the FPC connection section 50 of FIG. The mounting surface of the FPC, which is the side surface of the head arm 60 of the actuator 44, forms a step 56 which is stepped down to the mounting side of the read / write FPC band 46.
In the step 56, a tip 46a of the read / write FPC band 46 having a tip attached to the retainer 45 is provided.

That is, the read / write FPC band 46 is pulled out after being pinched by the pinching portion 45a of the retainer 45 on the tip end side, and the tip end 46a is adhered to the retainer 45 with, for example, a double-sided tape. It is mounted in a step 56 formed on the side surface.

With the retainer 45 and the tip 46a of the read / write FPC band 46 attached to the step 56, the surface of the read / write FPC band tip 46a, that is, the land on which the connection pattern is formed, is connected to the relay FPC band.
The PC 52 is installed so as to be flush with the mounting surface to which the PC 52 is adhered and fixed. The connection and fixing of the relay FPC 52 to the read / write FPC band tip 46 a adhered to the retainer 45 in the step portion 56 is performed by screwing the retainer 45 to the actuator 44 with the screw 54.

FIG. 8 shows a relay FP which is adhered and fixed to a side surface of the actuator 44 shown in FIG.
C52 is taken out. This relay FPC 52 is
It is divided into three PCs 52a, 52b and 52c. Each of the FPCs 52a to 52c has lands 58a, 58b, and 58c formed on the connection side of the relay FPC band 46, and has lands 59a to 59c formed on the head. Each of the lands 58a to 58c and 59a to 59c is provided with a rectangular connection pattern.

In this embodiment, the head 18 is a composite head and includes a write head using an inductive head and a read head using an MR head.
Therefore, four rectangular connection patterns are formed on the land portions 59a to 59c in FIG. 8 corresponding to the four sets of write heads and read heads. Four rectangular connection patterns are also formed on the lands 58a to 58c to which the read / write FPC bands are connected by superposition corresponding to the four rectangular connection patterns.

FIG. 9 shows the FP of the present invention shown in FIG.
The C mounting structure is shown in comparison with the conventional structure. FIG.
(A) shows the FPC structure of the present invention, in which the head arm 60
A step portion 56 is formed on the mounting surface of the FPC band 46, and the retainer 45 and the land portion of the read / write FPC band 46 are inserted into the step portion 56 in a superposed state. Are located on the same surface as the mounting surface 52a of the relay FPC 52 with respect to the head arm 60. Therefore, the connection surfaces of the land portions at the ends of the read / write FPC band 46 and the relay FPC 52 can be made the same.

On the other hand, in the conventional structure, FIG.
(B) As shown in (C) or (D), the head arm 6
No. 0, the retainer 45 and the read / write FPC band 46 are superimposed on each other, and the land portion is superimposed on the front end of the relay FPC 52 from the opposite side, and the land portion is superimposed and fixed.

For this reason, the positional deviation in the left-right direction is caused by the height of the land portion at the tip of the relay FPC 52, and a deviation occurs between the designed land portion size and the actual positioning dimension. Land portions 58a-
The connection patterns 58c are displaced from each other to cause a contact failure. Therefore, high-precision positioning for accurately positioning the rectangular connection patterns formed on the lands is required. Such a problem is caused by the problem of the present invention shown in FIG.
All are solved in the PC structure. 3. FIG. 10 shows an example in which the offset correction value is stored in RAM.
3 is a functional block diagram illustrating a process of storing and generating offset correction data used for offset correction of a head position performed by the CU 24.

In FIG. 10, a ROM table 62 and a RAM table 64 are used for storing offset correction data. ROM table 62 and RAM table 64
Uses a ROM element 62a and a RAM element 64a built in the MCU 24 of FIG.

In the disk drive 10 according to the present invention, the RA built in the MCU 24 is used for cost reduction.
Since a memory having a small memory capacity is used for M, the area that can be used for storing offset correction data is limited, and the offset correction data is stored by effectively using the limited RAM area.

FIG. 11 shows an embodiment of the ROM table 62 and the RAM table 64 in which offset correction data for correcting a mechanical bias force with respect to the cylinder position of the disk medium is measured by dividing into zones.

FIG. 11A shows a measured value of an offset current flowing through the VCM 20 in order to remove a mechanical external force on the two disks 18 shown in FIG. 4 with respect to the cylinder position. Since the disk 18 of the present invention has a storage area of, for example, 4096 cylinders, it is first divided into eight zones Z1 to Z8 in units of 512 cylinders.

This mechanical biasing force depends on the bending force of the relay FPC band 46 connecting the base FPC 48 to the actuator 44 as shown in FIG. For this reason, since an external force increases at both ends on the outer side and the inner side, a large offset current is required to correct the external force, and since the external force is stable in the central portion, the amount is relatively small and the amount of change is small. The offset current for external force correction is a substantially straight line.

Referring to FIG. 11 (A), taking the external force offset characteristic 75A side as an example, in the present invention, the change of the offset current in the center zone Z4, Z5 of the four zones Z1 to Z8 is not changed. Since there are almost no straight lines, these two zones are regarded as one zone and the value of the offset correction current is stored. Here, the offset characteristic 75A measured for each of the zones Z1 to Z8.
Of the offset correction currents I1 to I7.

FIG. 11B shows a ROM table 62 having eight memory areas corresponding to eight zones Z1 to Z8 of cylinder positions. Here, MC in FIG.
The ROM element 62a built in the U24 is a RAM element 64
Since there is a sufficient margin in the storage capacity as compared with a, there is no problem in the capacity even if the memory area is provided for the zones Z1 to Z8.

In eight memory areas of the ROM table 62, pointer information P1 to P7 indicating storage positions of the bias force correction currents I1 to I7 stored in the RAM table 64 shown in FIG. 11C are stored. I have. Since two of the zones Z4 and Z5 are regarded as one zone, the same pointer information P4 is stored, and the bias information correction current I4 in the fourth memory area of the RAM table 64 is referred to by the pointer information P4. I can do it.

Thus, the zone Z with respect to the cylinder direction
If it is desired to make a plurality of zones into one zone according to the characteristics of the offset data in 1 to Z8, the same pointer information is stored in the ROM table 62 and the offset correction data of the same storage area of the ROM table 64 is stored. The RAM table 6 can be referred to,
4, the number of memory areas can be reduced.

Referring again to FIG. 10, an offset correction data generator 65 is provided for the ROM table 62 and the RAM table 64. In the offset correction data generation unit 65, the current cylinder position X detected from the head position signal is set in the register 66, and the zone Zi to which the current cylinder position X belongs is first obtained in the zone address generation unit 68 and set in the register 70. And ROM
Refer to the table 62.

As shown in FIG. 11, pointer information is stored in the ROM table 62. The pointer information is read and the corresponding offset correction data in the ROM table 64 is read. The offset correction data A read first is held in the register 74. Subsequently, a zone Zi + 1 immediately adjacent to the current zone Zi is generated by the zone address generation unit 68 and set in the register 72. The zone Zi + 1 refers to the ROM 62 to obtain pointer information. With reference to the table 64, the corresponding offset correction data B is obtained,
It is stored in the register 76.

That is, as is clear from FIG.
For the zones Z1 to Z8, for example, the bias force correction current measured at the right zone boundary position is stored in the RAM 64 as offset correction data I1 to I7.

For example, the current cylinder position X in the zone Z1
Assuming that a head exists in the zone Z1, R
From the pointer information P1 obtained by referring to the OM table 62, only the offset correction data I1 at the zone boundary position on the left side of the zone Z1 can be obtained by referring to the RAM table 64.

In the present invention, since the offset correction data at an arbitrary cylinder position in the zone is obtained by linear interpolation of the measured values at the zone boundaries on both sides, the second ROM table for the adjacent zone Z2 is used. The pointer information P2 is obtained by referring to 62, the offset correction data I2 is obtained by referring to the RAM table 64, and the offset correction data I1,
I2 is obtained for linear interpolation. This is the acquisition of the offset correction data A by the zone Z1 and the acquisition of the offset correction data B by the next zone Zi + 1 shown in FIG.

The current cylinder position X is stored in the registers 74 and 76.
Are obtained at the zone boundary positions on both sides of the zone Zi to which the current cylinder position X and the interval C between the zone Zi are calculated in the interpolation calculation unit 78. Is calculated as interpolation data. That is, the interpolation data can be calculated as follows: interpolation data = A + [{(BA) / C} × (XA)].

As described above, the offset correction data generator 6
In the interpolation data generated in step 5, for example, during seek control, an offset correction current for removing the influence of an external force on the VCM is applied in addition to the speed control current. During the on-track control, the obtained offset data is added to the position servo control loop based on the head position signal to remove the influence of the external force on the actuator.

FIG. 12 is a flowchart of the processing operation by the offset correction data generation processing section 65 of FIG. First, in step S1, the zone Zi is determined from the current cylinder position X, and the RAM Z is determined by referring to the ROM table 62.
The pointer information Pi of the table 64 is obtained. Subsequently, in step S3, the ROM table 62 is stored in the adjacent zone Zi + 1.
To obtain the RAM pointer information Pi + 1.

Subsequently, in step S4, the pointer information P
The correction values A and B are obtained in step S5 by referring to the RAM table 64 based on i and Pi + 1. Then step S
In step 6, linear interpolation calculation for obtaining a correction value of the current cylinder position is performed, and in step S7, the calculated interpolation data is output.

FIG. 13 shows the zone division and the contents of the ROM table 62 and the RAM table 64 according to the embodiment of FIG. 10 for the position sensitivity correction data.

FIG. 13A shows the position sensitivity correction value for the cylinder position. The position sensitivity correction value is
This is a coefficient for converting the head position read from the servo information of the disk medium into a theoretically correct head position, and this is a position sensitivity correction value K. The position sensitivity correction value K is, for example, as shown in FIG.
It is changing relatively slowly.

Therefore, in FIG. 13A, as in the case of the external force correction in FIG. 11, the cylinder direction is divided into eight zones Z1 to Z8 at equal intervals.
ROM with 8 memory areas like 3 (B)
A table 62 is prepared. Here, the characteristic of the position sensitivity correction value in the cylinder direction linearly increases in the zones Z1 to Z5, and linearly decreases in the remaining zones Z6 to Z7.

Here, the zone Z8 is an area which cannot be used by the user as the system zone, and the measured value of the zone boundary is fixedly used for the zone Z8. Therefore, the zones Z1 to Z5 are collectively regarded as one zone. For this reason, the pointer information P1 is stored in the area corresponding to the zones Z1 to Z5 of the ROM table in FIG.
Are all stored. The pointer information P1 is shown in FIG.
The position sensitivity correction value K1 stored at the first position of the RAM table 64 is referred to.

Next, the zones Z6 and Z7 are regarded as one zone, the same pointer information P2 is stored in the corresponding memory area of the ROM table 62, and the pointer information P2 is used at the zone boundary position on the left side of the zone Z of the RAM table 64. The measured position sensitivity correction value K2 is referred to. For zone Z3, pointer information P3
Is stored in the ROM table 62 so that the position sensitivity correction value K3 in the third memory area of the RAM table 64 can be referred to.

For such a linearly changing position sensitivity correction value, the linear portion is regarded as one zone. In this case, the memory area of the RAM table 64 is set to 3 for the eight zones Z1 to Z8. Can be reduced to one.

FIG. 14 shows an example of the BL division data and ROM for correcting BL (multiplied value of magnetic flux B and coil length L) in the cylinder direction by the permanent magnet used in the VCM. Table 62 and R
3 shows the contents of the AM table 64.

FIG. 14A shows the offset correction characteristic of the bias force with respect to the cylinder position. The offset of the bias force is usually obtained as a measured value of the open loop gain G. The open loop gain G indicating the offset due to BL is small at the inner and outer cylinder positions, flat at the central portion, and changes non-linearly therebetween.

As for the open loop gain for correcting the BL in FIG.
A memory area corresponding to the ROM table 62 is secured by dividing the area into Z8. Here, the measured values at the respective boundaries of Z1 to Z8 are G1, G2, G3, and G4, and the offset characteristics are substantially symmetric.

Therefore, the central zones Z4, Z5, Z
The same pointer information P4 is stored in the ROM table 62 by regarding three of the six as one zone so that the open loop gain G4 of the RAM table 64 can be referred to. The left and right zones Z3 and Z7 are regarded as symmetrical, and the same pointer information P3 is stored to refer to the open loop gain G3 of the RAM table 64.

Similarly, the zones Z2 and Z8 are regarded as symmetric zones, the same pointer information P2 is stored, and the open loop gain G2 of the RAM table 64 is referred to. Further, for the zone Z1, its own open loop gain G1 is stored in the RAM table 64.

Further, as for the characteristics in the case where a flat straight line portion is provided at the center of FIG. 14, the interpolation calculation need not be performed for the zones Z4 and Z5. Interpolation calculation is zone Z
This is performed only for the non-linear portions 1, 1, Z2, Z3, Z6, and Z7. In addition, since the zone Z8 is not a user area, for example, an open loop gain G1 is fixedly used, and since it is a constant value, linear interpolation is not necessary even when reaching this part.

In the above-described embodiment, the external force offset correction data, the position sensitivity correction data, and the bias force correction data are taken as examples of offset correction data. The corresponding appropriate offset correction data can be applied as it is. 4. Measurement of Position Sensitivity Correction Value FIG. 15 is a block diagram of a function of measuring a position sensitivity correction value in the disk device of the present invention. In FIG. 15, a position sensitivity measuring unit 80 is started at the time of shipment, startup, or at a desired calibration timing of a disk drive, and reads a two-phase servo information read signal divided into sectors on the data surface of the disk. The position sensitivity correction value is measured based on the two-phase servo signals N and Q obtained from the above.

The position sensitivity correction value is measured by dividing the disk into eight zones Z1 to Z8 in the cylinder direction, for example, as shown in FIG. 13, and measuring the cylinder position at the boundary of each zone. First, the two-phase servo pattern on the magnetic disk used for measuring the position sensitivity correction value of the present invention is as shown in FIG.

In FIG. 16A, the horizontal axis is the disk radial direction, and the vertical axis is the disk rotation direction (track direction).
Servo pattern for one servo frame is assigned to cylinder number 1
4 are shown. For example, focusing on cylinder number 1, the two-phase servo patterns are four patterns of A, B, C, and D, and the phases are switched by dividing one track pitch into １ ／ track pitch.

That is, the pattern A is first recorded with a 1/3 track pitch width, then the pattern B is recorded with a 1/3 track pitch shift, and the pattern B is recorded with a 2/3 pitch width. Pitch shifted pattern C
Is recorded with a 2/3 track pitch width, and a pattern B
Pattern D shifted by 1/3 track pitch
Are recorded at a 2/3 pitch width.

The last AGC pattern is recorded continuously in the disk radial direction. 16A of FIG.
MR head 18a as a read head for two-phase servo patterns A to C whose phases change at a pitch of ~ 3 tracks
FIG. 16B shows two-phase servo signals N and Q obtained when the disk is sought at a constant speed in the disk radial direction. Here, the servo signal N is the difference between the read signals of the patterns A and B, and the servo signal Q is the difference between the read signals of the patterns C and D. That is, N = AB Q = CD is obtained. The generation of the two-phase servo signals N and Q based on the read signals of the two-phase servo patterns A to C is performed by the servo signal generation unit 84 in FIG.

The servo signal N, obtained from the two-phase servo signal whose phase changes at the first to third track pitches in FIG.
Q is the on-track position at the time of read / write, and the zero-cross position 10 of the servo signal Q indicated by the circle of the cylinder numbers 1-4
It becomes 0.

On the other hand, in the position sensitivity correction value measurement processing of the present invention, the head is moved on-track to the measurement positions 102 and 104 of the cylinder numbers 2 and 4 which are the cross points of the servo signals N and Q. On-track control is performed, and a position sensitivity correction value is obtained from the signal value of the cross point obtained at this time.

Here, the measurement position 102 of the cross point of cylinder number 2 is on the + side, the measurement position 104 of the cross point of cylinder number 4 is on the-side, and each of the cross point of + and the cross point of-is measured. By doing so, errors due to vertical asymmetry in the read signal of the MR head 18a are reduced.

That is, the measured value of the cross point is determined from the average value of the absolute value of the measured value of the + cross point obtained at the measuring position 102 and the measured value of the negative cross point obtained at the measuring position 104. By dividing the theoretical value of the cross point by this measured value, a position sensitivity correction value is calculated.

FIG. 17 shows a two-phase servo signal N, Q for on-track control of the crossing point of the measurement position by the position sensitivity measuring unit 80 of FIG. 15, and a head position signal generated from the two-phase servo signals N, Q. FIG. 9 is an explanatory diagram of a signal obtained by further connecting a head position signal.

FIG. 17A is the same as FIG. 16B as FIG.
6 (A) are two-phase servos N and Q obtained from signals read by the MR head 18a from the two-phase servo patterns A to C that change phase at the 1-2 track pitch. These two-phase servo signals N and Q correspond to cylinder numbers 1 and 3 in FIG.
That is, as shown in the non-measurement cylinder, the head position signal is linearly changed from-to + and is converted into a head position signal, and the characteristic straight line at the on-track position 100 at the time of read / write passes through the zero point.

FIG. 17 shows the actual head position control.
As shown in FIG. 17C, each head position signal during one track pitch obtained in FIG. 17B is processed as a continuous signal by adding a predetermined offset. However, with the head position signal at the normal on-track position 100, the on-track control cannot be performed at the measurement positions 102 and 104 where the two-phase servo signals N and Q cross as in the measurement cylinders 2 and 4.

Therefore, in the position sensitivity correction value measurement processing of the present invention, the head position signal is obtained from the two-phase servo signals N and Q unique to the measurement cylinder for the measurement cylinders 2 and 4 where the cross points 102 and 104 exist. Set the desired conditional expression.

FIG. 18 shows the conditions of the two-phase servo signals N and Q for generating the head position signals of FIG. 17B used in the measuring cylinders 2 and 4, and the equations for calculating the head position signals under each condition. is there. By applying the calculation formula according to the condition of FIG. 18 to the measurement cylinders 2 and 4 of FIG. 17A, the measurement of the cross point measurement position 10 as shown in FIG.
2 and 104, the head position signal can be converted into a signal passing through the zero point.

FIG. 17 obtained by measuring cylinders 2 and 4
Since each signal curve for each one-third of (B) and the rack pitch is obtained including the flat portions of the two-phase servo signals N and Q in FIG. °, a bent line change in which the slope is dull at both ends.

Further, the head position signals obtained by the measuring cylinders 2 and 4 are offset by the offset according to the conditions of the two-phase servo signals N and Q defined in the first offset table 90 and the second offset table 92 shown in FIG. FIG. 17C shows a case where the values are connected to each other.

FIG. 17C shows the track pitch of the measuring cylinder 2 in the first offset table 9 shown in FIG.
FIG. 17B shows a state in which the head position signals shown in FIG. As described above, by using the calculation formula according to the condition of FIG. 18 and the offset value according to FIG.
At 2104, the head position signal is set to zero to generate a head position signal that can be controlled on-track.

The generation of the head position signals shown in FIGS. 17A, 17B and 17C is performed by the head position generation unit 86 shown in FIG. The offset value of the table 90 is used, and the offset value of the second offset table 92 is used for the measurement cylinder 4.

The head position signal used at the time of offset measurement obtained by the head position generating section 86 is applied to an addition point 94, and is added to the target position signal indicating the measured position of the cross point provided by the position sensitivity measuring section 80. The deviation is taken out, and the deviation is given to the position servo control unit 96, and a current is supplied to the VCM from the addition point 98 to perform on-track control to the target position 102 or 104 serving as a cross point.

Then, in the on-track state to the zero-cross point serving as the measurement position, the position sensitivity correction value measuring section 80
Measured the value of the cross point from the values of the two-phase servo signals N and Q from the servo signal generator 84 obtained at that time, and obtained the measured value of the + cross point and the measured value of the-cross point. Sometimes, the average value of the sum of the absolute values of the two is calculated, and the theoretical value of the cross point is divided to obtain the position sensitivity correction value. In the actual position sensitivity measurement, an average value of the measured values of a plurality of cross points obtained in a state where the position sensitivity is on-track to the measuring cylinder is used.

Further, the position sensitivity measuring section 80 instructs the seek control section 82 to perform seek control to the measurement cylinder position. That is, in the position sensitivity measurement of the present invention,
Since the cylinder position is divided into, for example, eight zones and the position sensitivity correction value is measured for each cylinder position on the zone boundary, the cylinder address of the zone boundary is set in the seek control unit 82 for each position sensitivity measurement and the seek is performed. After the seek control is completed, on-track control of the measurement cylinder by the position servo control unit 96 is performed.

As shown in FIG. 17, when the measurement of the cross point on the + side at the first measurement position 102 at the cylinder number 2 is completed, the seek control unit 82 is instructed to perform a two-track seek, and After seeking to the measuring cylinder 4 having the measured value 104, a process of generating and measuring a head position signal for on-tracking to a cross point where the measured value 104 is obtained is performed.

FIG. 20 is a flowchart of the process for measuring the position sensitivity correction value in FIG. First, a measurement zone is set in step S1, and then in step S2
Sets the first measurement cylinder at the boundary position of the measurement zone. Subsequently, in step S3, seek to the measuring cylinder is performed. In step S4, on-track control is performed to a measuring position that is a cross point of the measuring cylinder. In step S5, the voltage + Vc at the cross point is measured.

Subsequently, in step S6, +2 track seek is performed on the next measurement cylinder, and in step S7, on-track is performed on the position of the zero cross point of the sought measurement cylinder.
In step S8, the voltage -Vc at the cross point is measured. Subsequently, in step S9, the positive and negative measured voltages + Vc and -Vc are output.
An average value of the absolute values of Vc is determined, and a theoretical value of a predetermined cross point is divided by the average value to calculate a position sensitivity correction value at that position, and the calculated value is stored in a table. Subsequently, in step S10, it is checked whether or not all the zones have ended, and the same processing is performed for the boundary cylinder positions of all the zones.

As described above, even when the servo pattern of the two-phase servo signal is recorded with the phase change of the 1/3 track pitch being recorded, the position of the cross point to be measured exists every other track by the on-track control. In other words, by increasing the interval between the cross points, the density at which the cross points are measured can be reduced, and the measurement time can be shortened.

Further, since the value of the cross point is directly measured by on-tracking the position corresponding to the cross point, the measurement accuracy of the zero cross point is smaller than that obtained by linear interpolation from the values before and after the conventional cross point. Is improved in each stage, and the measurement accuracy of the position sensitivity correction value obtained from the measurement result can be greatly improved.

Further, since the measurement of the position sensitivity correction value is performed in each zone, even if the number of cylinders increases, the number of measurement points does not increase so much. The measurement can be simplified and the capacity of the RAM table for storing the position sensitivity correction value can be reduced. 5. Encoding / Decoding Loss FIG. 21 is a block diagram of a circuit unit that generates a write gate signal and a read gate signal used in the disk device of the present invention.

First, the disk medium of the present invention employs a data surface servo in which servo frames are recorded at predetermined intervals on a track and the interval between servo frames is divided into a plurality of sectors. Therefore, a sector mark is recorded at the head position of each sector provided following the servo frame,
By reading this sector mark, a sector pulse is obtained.

In the disk drive of the present invention shown in the figure, the read / write unit 38 of the control unit 12 performs signal processing in accordance with the partial response maximum likelihood method, that is, encodes NRZ data at the time of writing. Demodulation from the head read signal to NRZ at the time of read operation, a loss of, for example, about 40 bits occurs at the time of encoding and at the time of decoding, respectively.

Conventionally, the processing shown in the time chart of FIG. 22A is performed for such encoding loss and decoding loss. FIG. 22A shows a servo detection signal,
It shows each signal of a sector pulse, a write gate, and a read gate. The servo frame signal is obtained by detecting the servo frame. The servo frame signal is divided into four sectors in this conventional example, and a sector mark is recorded at the head position of each sector, which is obtained as sector pulses indicated by numbers 1, 2, 3, and 4. Can be

The write gate signal is generated at the rise of the sector pulse following the servo frame signal during the write operation, and the NRZ signal for writing is input to the read / write unit 38 in the write state of FIG. 2 for one sector. Until it is on. When the write gate signal turns off,
Behind the gap region, there is provided a gap region for the encode loss time Tw during the write operation.

On the other hand, the read gate signal corresponds to the read gate signal for the decode loss time Tr from when the head read signal is obtained from the rise of the sector pulse during the read operation to when the NRZ signal is output to the hard disk controller 34. And is turned on for a read time of one sector.

Referring again to the write gate signal, after the gap area corresponding to the encode loss time Tw after the write gate signal is turned off, the gap area corresponding to the decode loss time Tr generated for the read gate signal is set. Provided.

That is, in the conventional sector servo format, the loss time To (= Tw + T) obtained by adding the encode loss time Tw during the write operation and the decode loss time Tr during the read operation after the write gate signal is turned off.
r) gap regions are provided. For this reason, a gap area corresponding to a loss obtained by adding the encoding loss and the decoding loss must be secured in the sector area, and the format efficiency is reduced.

Therefore, in the present invention, first, FIG.
As shown in the time chart of the servo frame, sector pulse, and write gate signals at the time of the write operation (B), in the sector format of the disk medium, the gap area after the write gate signal is turned on after being turned off is written. Only the encoding loss time Tw in the operation is set.

In the sector format in which the gap area at the last position of each sector is the encoding loss time Tw in the write operation, during the read operation, as shown in FIG. The detected sector pulse is delayed by the encoding loss time Tr during the read operation, and a read gate signal is generated in synchronization with the rise of the delayed sector pulse.

Due to the delay of the sector pulse decoding loss time Tr during the read operation, FIG.
As shown in (B), there is no need to provide a gap area in which the encoding loss time Tw is added to the decoding loss time Tr at the end position of the sector format.
The format efficiency of the disk medium can be improved because the gap area for r is not required.

For example, in the case of FIG. 22, although the interval between servo frames was 4 sectors as shown in FIG. 22A in the past, in the format according to the present invention of FIG. Up to 3% of the sector area can be increased.

The operation of the circuit shown in FIG. 21 will be described. At the time of writing, the sector pulseless table 100 in consideration of the encoding loss is loaded into the sector pulse generation circuit 102, and the sequencer 104 is activated by the sector pulse,
The write gate signal becomes active. Subsequently, the buffer RA up to the gap area corresponding to the encoding loss
When the buffer manager 106 recognizes that data has been transmitted from the M108, the sequencer 104 stops the write gate signal. This is repeated for each sector pulse.

At the time of reading, the sector pulse generation circuit 102 stores the sector pulse table 100 in consideration of the decoding loss.
, The sequencer 104 is activated by the sector pulse, and the read gate signal becomes active. Subsequently, when the buffer manager 106 recognizes that necessary data has been received in the buffer RAM 108, the sequencer 104 stops the read gate signal.

Here, each sector pulse table 100 used at the time of writing and at the time of reading holds a value determined for each zone on a program, and sets a value corresponding to the zone at that time.

The embodiment shown in FIG. 21 uses a data surface servo in which servo frames are recorded on the data surface at fixed intervals as an example. However, the servo surface servo using a dedicated servo information recording surface also has a data surface servo. The same applies to the sector format.

[0112]

As described above, according to the present invention, the connection surfaces on both ends of the read / write FPC from the base side of the head actuator and the relay FPC on the head side are formed with the same connection surface. Since it can be a mounting surface, the positioning dimension in design and the positioning dimension in actual assembling can be made the same, and the positioning accuracy can be easily improved.

Further, since the read / write FPC band side and the retainer are incorporated into the step formed by stepping down on the FPC mounting surface of the actuator, the read / write FPC can be stably mounted on the head actuator. According to the present invention, the RA storing the correction data is determined by the pointer information of the ROM table.
By arbitrarily specifying the storage location of the M table,
The interval at which the correction is performed can be changed, and the area used by the RAM can be reduced to a minimum.

Further, according to the present invention, even when the servo pattern of the two-phase servo signal is recorded in a phase change of 1/3 track pitch, the position of the cross point to be measured by the on-track control is one track. As a result, the density at which the cross points are measured decreases, and the measurement time can be reduced.

Further, according to the present invention, the gap area provided at the last position of each sector on the track is the gap area corresponding to the encoding loss at the time of the write operation, and the loss area obtained by adding both the conventional encoding loss and the decoding loss is used. As compared with the case where a minute gap area is provided, the decrease in format efficiency can be improved, and the disk capacity can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a block diagram showing the overall configuration of the present invention.

FIG. 3 is a structural explanatory view of the disk enclosure of FIG. 2;

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is an explanatory view showing the actuator of FIG. 3 together with an FPC.

FIG. 6 is a side view of the actuator of FIG. 5 on the FPC mounting surface side.

FIG. 7 is an enlarged view of the FPC mounting structure of FIG.

FIG. 8 is an explanatory view of the relay FPC of FIG. 6;

FIG. 9 is an explanatory view showing an FPC mounting structure of the present invention in comparison with a conventional structure.

FIG. 10 is a functional block diagram of storing offset correction data and generating interpolation according to the present invention;

FIG. 11 shows an example of external force offset correction data.
0 ROM table and RAM table

FIG. 12 is a flowchart of offset correction data generation processing of FIG. 10;

FIG. 13 shows an example of position sensitivity correction data.
0 ROM table and RAM table

FIG. 14 shows the ROM of FIG. 10 taking BL correction data as an example
Illustration of table and RAM table

FIG. 15 is a functional block diagram of the processing for measuring the sensitivity of the present invention.

FIG. 16 is an explanatory diagram of a two-phase servo pattern and a demodulated two-phase servo signal.

17 is an explanatory diagram of a two-phase servo signal, a head position signal, and a signal obtained by connecting the head position signal at the time of the position sensitivity measurement of FIG.

FIG. 18 is an explanatory diagram of a condition table used for calculating a head position signal at a measurement cylinder position at a cross point in FIG. 17;

FIG. 19 is an explanatory diagram of an offset table used to connect the Henu position signals at the cross points in FIG. 17;

FIG. 20 is a flowchart for position sensitivity measurement in FIG. 15;

FIG. 21 is a block diagram of a generation unit of a read gate and a write gate used in the present invention.

FIG. 22 is a time chart showing the occurrence of a read gate and a write gate according to FIG. 21 in comparison with a conventional case;

[Explanation of symbols]

 10: Disk drive 12: Control unit 14: Enclosure 16: Spindle motor (SPM) 18: Disk 20: Voice coil motor (VCM) 22: Head 24: MCU (micro control unit) 26: Oscillator 28: Logic IC 30: Program Memory 32: Servo controller 34: Hard disk controller (HDC) 36: Buffer memory 38: Read / write unit 40: Host system 42: Sensor IC 44: Actuator 46: Read / write FPC band 48: Base side FPC 50: FPC connection unit 52: Relay FPC 54: Screw 56: Step 58a-58c, 59a-59c: Land 60: Head arm 62: ROM table 64: RAM table 66, 70, 72, 7 4, 76: register 68: zone address generation unit 78: interpolation calculation unit 80: position sensitivity measurement unit 82: seek control unit 84: servo signal generation unit 86: head position generation unit 88: multiplexer 90: first offset table 92: Second offset table 100: Sector pulse table 102: Sector pulse generation circuit 104: Sequencer 106: Buffer manager 108: Buffer RAM

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhide Oba 5400 No. Omori, Higashi-nemoto Higashi-ne, Higashi-ne, Yamagata Prefecture 2 (No address) Inside Yamagata Fujitsu Co., Ltd. Former Higashi Neji Omori 5400 No. 2 (No address) Yamagata Fujitsu Limited F-term (reference) 5D088 BB11 5D096 AA02 CC01 EE03 FF02 GG07 KK14

Claims (6)

[Claims] 1. Two-phase servo signals N and Q detected from a read signal of two-phase servo information recorded on a disk surface are converted into correct head position information using a position sensitivity correction value measured in advance. In the disk device, a disk medium on which the two-phase servo information is recorded so that a phase changes at a 1/3 cylinder pitch on the disk surface, and when measuring the position sensitivity correction value, A disk device comprising: a position sensitivity measuring unit that performs on-track control on a cross point of the obtained two-phase servo signals N and Q, measures a value of the cross point, and obtains a position sensitivity correction value. . 2. The disk device according to claim 1, wherein the position sensitivity measuring section measures a value at a position where the cross point is on the plus side and a value at a position where the cross point separated by two tracks is negative. The disk device according to claim 1, wherein the position sensitivity correction value is calculated as an average value of absolute values of the two measured values. 3. The disk device according to claim 1, wherein the position sensitivity measuring section calculates a correction coefficient for correcting the measured value of the cross point to a theoretical value as a position sensitivity correction value. A disk device characterized by the above-mentioned. 4. The disk device according to claim 1, wherein the position sensitivity measuring section divides a recording area of the disk medium into a plurality of zones and measures a position sensitivity correction value for each zone boundary position. A disk device for performing head position control by obtaining a position sensitivity correction value at a current position by linear interpolation from position sensitivity correction values at two boundary positions of a zone where a head is located, and performing correction. . 5. A disk drive according to claim 1, wherein a track of the disk medium is divided into a plurality of sectors, and a sector mark is recorded at a head position of each sector. In a disk device that generates a write gate signal or a read gate signal based on the gap region, a gap region provided at a final position of each sector of the disk medium for a time corresponding to an encoding loss due to a write operation, A write gate generator for generating a write gate signal in synchronization with a sector pulse and stopping the write gate signal in response to the detection signal of the gap area; and a sector delayed during a read operation by a time corresponding to a decoding loss due to the read operation. A read gate signal is generated in synchronization with the pulse, A read gate generating unit stopping the read gate signal detection signal by a signal obtained by time-delayed corresponding to the decoding loss,
A disk device comprising: 6. The disk device according to claim 5, wherein each of the gap area corresponding to the time corresponding to the encoding loss and the delay time corresponding to the decoding loss is set to a value corresponding to the cylinder position of the head. A disk device characterized by setting.