JPS61211814A - Disc device - Google Patents

Abstract

PURPOSE:To improve the head positioning accuracy by recording built-in servo information representing its position corresponding to each track with a write current whose level is changed at least once from the inner circumference track to the peripheral track. CONSTITUTION:The bult-in servo information representing its position corresponding to each track is recorded and the servo information is recorded by using a write current whose level is changed at least once from the inner circumferential track to the peripheral track. That is, plural tracks are formed concentrically in a data track area 3b on the recording face and track numbers are given in order from the peripheral toward inner circumference. A sector face servo information area 3d is made on the disc 3 and the built-in servo information representing the radial position of each track is recorded in the area. When the disc 3 is turned and the servo information area 3d passes under the head 11, a CPU 23 applies tracking control only once per revolution of the disc 3 based on a servo signal.

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a disk device having a disk-shaped recording medium, and more particularly, a plurality of concentrically arranged tracks are defined, and a recording medium is provided to each one of the tracks. The present invention relates to a disk device equipped with a disk on which embedded servo information indicating the position of a rank is recorded. With the recent progress in office automation, various types of information processing devices such as word processors and office computers have become widespread, and there is a need for compact recording devices with a high response rate. Bar 1 - Disk devices were either small or large in size, so their application to office information processing equipment was limited, but recently small hard disk devices have been announced. and is expected to be applied to various information processing devices. The so-called "Winchester" type device in which the combination of the bar 1 and the disk is fixed is dominant as such a disk device, but it is generally rotatable and magnetically attached. It is equipped with a disk on which data can be recorded automatically, and a writing/reading system having a magnetic eight 1- for writing data on the disk and reading data recorded on the disk. ing. A plurality of concentric tracks are defined on the magnetic disk, and data is written or read by accessing a desired track by using the above-mentioned eight tracks. In this case, it is necessary to accurately position the magnetic head 1- on the desired track. Conventionally, in order to position the head and the track, a dedicated disk surface for trunk positioning and a dedicated eight Servo surface servo (dedicated 5ervo) using 1- and
method and partial servo information coating at predetermined locations on the circumferential track

[Embedded servo (embedded 5erv)
o) method is widely used. In the latter case, there are two methods: one is to place servo information between sectors of the track, and the other is to put servo information in the index section once per track. It is called. Note that there are two methods for accessing the disc by moving the 81- relative to the disk: a swing arm method and a linear method. There is. Furthermore, servo configurations include those that use a voice coil motor and those that use a stepping motor. Those that use a voice coil motor are complicated to control and are expensive, while those that use a steno pin motor are The ones used are generally inexpensive, but have the disadvantage that their control becomes complicated when trying to improve positioning accuracy. In such a hard disk device, the disk is
Usually, the disk is rotated at a predetermined speed, and the head is moved relative to the disk to access a desired track. As mentioned above, one rack is formed in a concentric shape, so the inner track is shorter in length. Therefore, if recording is performed at a constant recording cycle, the inner track will have a shorter recording time. As the density increases, interference between adjacent recorded data increases. In addition, since the disk is driven and rotated at a constant speed, the gap between the head and the disk becomes narrower as it moves toward the inner track, and the magnetic field applied to the disk by the 8-1 increases, which also causes the gap between adjacent data to become narrower. Interference increases. In this way, when there is interference between adjacent data, the recording signal level decreases accordingly, and therefore, in general, the recording signal level decreases toward the inside of the disk. by the way,
Servo information for head positioning is also recorded on the disk corresponding to each track, so if the same recording current is used to record on the disk, the playback output will go to the inner track. There is a disadvantage in that the circuit that processes the servo information must allow for a margin for this decrease. ■-Momme The present invention has been made in view of the above points, and an object of the present invention is to provide a disk device that eliminates the drawbacks of the prior art as described above and makes it possible to significantly improve head positioning accuracy. do. The present invention provides a disk device comprising a disk that is driven and rotated at a predetermined speed and is capable of recording information, and a writing/reading means that writes information to the disk and reads information recorded on the disk. A plurality of concentric tracks are formed on the disk, and embedded servo information representing the position of each track is recorded corresponding to each track, and the embedded servo information extends from the inner track to the outer track. Specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. do. . FIG. 1 shows an example of a hard disk device to which the present invention is applied, which has a bar 1, a disk device 1, a base 2 formed in a predetermined shape as a casing or chassis, and a recording medium. A disc 3 is rotatably housed in the base 2. As will be described later, in this example, a pair of disks;
, 5 b-J2, and each disk 3
Both sides of the disc are configured as recording surfaces. disc 3
is driven at a predetermined speed in the six directions of arrows by a DC motor, which will be described later.Although not shown in FIG. The number of the outermost track is 00, and the number is set so that it increases sequentially toward the innermost track.In Fig. 1, the right side of disk 3 In the illustrated example, the carriage 4 moves the disk 3 through six rollers 5a to 5d (only rollers 5a and 51 are shown in FIG. 1). The guide members 6a to 6c are fixedly attached to the base 21-, and the carriage 4 is guided by these guide members 6a to 6c. disc 3
It is free to reciprocate in the radial direction relative to the radial direction. The carriage 4 is further provided with an arm support 4a, which extends in the radial direction of the disk 3 and allows the four arms]-〇 (flexure) to be perpendicular to each other. They are supported in parallel. A magnetic head ] 1 is fixed to the tip of each arm 10 . A drive belt 7 is provided on the carriage 4 with its both ends 7a and 7b fixedly attached. The bell l to 7 has a long throat 1 bored in its left half, and a slip 1 to lip portion whose width is slightly narrower than the width to the throat 1 is formed in its right half. The bell 1 to 7 has its slip 1 to lip portion inserted through the thrower 1- and wound around the pulley 8 once. The pulley 8 is fixed to the rotation of a stepping motor 9 fixed to the base 2. Therefore, by reversibly rotating the stepping motor 9, the carriage 4 is reciprocated in the horizontal direction in FIG. 1 via the pulley 8 and the bells 1-7. still,
In Figure 1, the position of the carriage 4 indicated by a solid line is the position where the carriage 4 is closest to the disk 3, while the position where the carriage 4 is farthest from the disk 3 is indicated by a chain double-dashed line. be. The space within the base 2 in which the disk 3, carriage 4, etc. are disposed has a sealed structure to prevent dust from entering from the outside. The rotation of the disk 3 causes movement of airflow within the sealed space of the present apparatus, as shown by the arrow, and the airflow is constantly purified by passing through the filter 12. still,
Brackets 1 to 13 and 14 are fixed to both ends of the base 2. FIG. 2 roughly shows a cross section taken along the line x--X in FIG. 1. As shown in the figure, a spindle motor 15 is provided fixed to the base 2, and its driving rotation speed is 1.
A pair of disks 3.3 are fixed to the disk 3.3 at a distance from -1- below through a hub], 5)). As mentioned above, both surfaces of the disk 3 are recording surfaces, and therefore, a total of four magnetic heads 1- are provided opposite to both surfaces of each disk 3. Each magnetic head is fixed to the tip of the arm 10, and when the disk 3 is at rest, the disk 3
When the disk 3 is driven and rotated, the airflow generated thereby causes the disk to be in contact with the surface 1-;
Float above the surface of 3. FIG. 3 is a side view of the hard disk device 1,
A printer 1 - circuit board] 9 is fixed to the bottom of the base 2 via bosses 1 to 18a and 18b.
-Circuit board] The lower surface of -9 constitutes a component mounting surface,
Although its details are not shown, a drive control circuit of the present device 1 is configured. Incidentally, FIG. 3 shows the thermistor 20 mounted on the printer 1 to the circuit board 19, and the mounting position of the thermistor 20 is also shown in FIG. -1 to bracket 1 through vibration-proof rubber 16a,]6b
0= Attached to base 2. FIG. 4 is a plotter diagram showing the system control circuit of the hard-tisf device shown in FIGS.
is formed. Although the block diagram of FIG. 4 shows typical signals exchanged between blocks, in reality, various other signals are used. As shown in the figure, a read/write control circuit 22 is provided connected to the magnetic head 1.
2 supplies read data to an external host device via an interface circuit 28, while receiving and receiving ride data from external hosts 1 to devices via the interface circuit 28. As mentioned above, on the disk 3, in addition to the data area used by the user to freely write and read data, there is also an index servo axis representing the track position in the form of a burst signal. recorded. Therefore, when the disk 3 is driven to rotate, the head 11, when in the read mode, reads not only read data but also periodic servo information. Therefore, when in the read mode, the read/write control circuit 22 discriminates between read data and read verse 1-, which is servo information.
The 1st line data is separately supplied to the interface circuit 28, while the 1st line data is separately supplied to the parse 1 to the averaging circuit 24, respectively. On the other hand, a proximity magnetic switch (not shown) is provided in the hard disk drive 1 shown in FIGS.
In cooperation with the holes drilled in the rotor of No. 5, an index detection signal is generated once per rotation of the rotor. This index detection signal is detected by the index signal detection circuit 21, and on the other hand, the index signal detection circuit 21 generates a servo index signal and an index signal based on it. The index signal is used for interfacing with the host side via the inch-face circuit 28. The servo index signal is supplied to the read/write control circuit 22 and used to distribute the read signal from the head 1 into read data and read verse 1-. On the other hand, the servo index signal is also supplied to a system controller 23 composed of a central processing unit (CPU). C
P T and J 23 receive a clock from an external clock source such as a crystal oscillator, and also receive servo signals obtained by averaging into read bursts from burst 1 to averaging circuit 24 . The CPU 23 supplies a driving signal to a driving circuit 25 for driving the spindle motor 15, and further supplies a driving signal to a stepping motor driving circuit 27 for controlling the driving of the stepping motor 9, which specifies the excitation time of the coil via a chopping circuit. In addition to supplying a duty signal for controlling phase excitation, a step signal for controlling phase excitation is also supplied. FIG. 5 shows an example of the configuration of the recording surface of the disc 3. As shown in FIG. In this example, on the recording surface, a data track area 3b is formed between a shopping landing area 3a on the inner circumferential side and an outer guard band area 3C on the outer circumferential side. A plurality of concentric tracks are defined within the data track area 3b, and track numbers are sequentially assigned from the outer circumference to the inner circumference. A sector-shaped servo information area 3d is defined on the disk 3'', and embedded servo information representing the radial position of each track is recorded in this area. Therefore, when the disk 3 rotates and the servo information area 3d passes below the head 11, the CPU 23 performs tracking control only once per rotation of the disk 3 based on the servo signal. FIG. 6 shows the principle of such index servo. That is, FIG. 6(a) shows the servo index signal IBS generated every 1st rotation of the disk 3.
Figure (b) shows that data is read from a desired track in the data track area 3b between adjacent index signals, that is, during one rotation of the disk 3, servo information is read from the data area and the servo information area 3b. This shows that a servo area is provided, and a speed tolerance gap is provided between them. This servo information area is an area that cannot be accessed by the user. Fig. 7 shows the principle of positioning to the spatula 1 using embedded servo information.1 Fig. 7 shows the recording surface of the disk 3.
2, three tracks 3]a, 3]-b, 3]0 are shown, each one is circular, and servo information 4]a to 4]d is provided between the ends of the track. There is one kick. That is, in this example, for J tracks, for example, track 3.1b, a pair of servo information 411] and 4
．． 1c is provided, and the servo information 41-b is also shared by the adjacent track 3]-a. That is, in this example, each piece of servo information 4 is located between the center lines of adjacent trunks. The position of the spatula 1-”1 on the disk 3 is marked with a solid line circle 3 for on I to rank.
On the other hand, a state of off-track to the outside is shown by a broken line circle 30a, and a state of off-track to the inside is shown by a broken line circle 30b. Furthermore, when the head 11 is in the on-track state (solid line circle mark 30), "l\so1 to 1"
The servo information is read from servo information 4lb and 4]c, and the portions to be read are shown hatched. It is assumed that the servo information is written in the form of a parse 1 signal. FIGS. 8(a) to (c) show that the head ]-] is on (-
Rack 30, outside off 1 rack 30a, inside off 1~
The signal output to the servo berth 1 read from each head in the case of rank 30b is shown. That is,
In the case of the on-I rack 30, as shown in FIG. 8(a), a pair of servo information 4l for the track 31b
The respective read burst signals 42 from b and 4.1c
The amplitude values of a and 42b are equal. On the other hand, in the case of off-track to the outside or inside, the amplitude of the burst signal read from each servo information differs depending on the amount of off-track, as shown in FIGS. 8(b) and (c), respectively. Based on the difference in amplitude values, C
The PU 23 calculates a correction value, and by changing the driving conditions of the stepping motor 9, it is possible to position the spatula 11 to a desired track -1-. Figure 9 shows the reproduction output as a function of the radius of the disk 3 when writing is performed with a constant recording current on the magnetic disk 3 and read with a head. . Therefore, even when the servo information is written as a constant burst signal, the level of the reproduced output decreases toward the inner circumference of the disk 3, as shown in the graph of FIG. The main causes of this drop in the playback output level are that waveform interference occurs between adjacent recorded data because the linear recording density increases toward the inner circumference, and that As the gap decreases and the strength of the magnetic field applied to the disk by the spatula 1- increases, waveform interference is promoted. In this way, when the reproduction output of servo information changes depending on the radius of the disk 3,
Such a change must be set aside as a margin in a circuit that processes servo information, and the off-track amount detection accuracy is reduced accordingly. Therefore, it is desirable that the reproduction output of the servo information recorded on the disk 3 is constant regardless of the radius of the disk 3. The present invention provides a disk device that uses a disk 3 on which servo information is recorded so that the reproduction output is constant. This is shown in Figure 10. In the illustrated recording and reproducing system, a reading system is constructed by connecting a reading/writing head 45 consisting of a coil, an amplifier 46, a filter 47, an amplifier 48, an MFM detector 49, a waveform shaping circuit 50.1, and a transmitter 51. With,
A write system is configured by connecting the head 45, a write 1 amplifier 52, a flip-flop 53, and a receiver 54. In the write system, a write control circuit 55 is provided connected to the write amplifier 52, making it possible to variably set write conditions by the head 45. The system shown in FIG. 10 can be incorporated into the present disk device, for example, but the servo information is usually
Since the user will never access it, the first
It is also possible to have a configuration in which the recording/reproducing system shown in FIG. 0 is provided separately and independently for writing servo information on the disk 3, and the disk 33 on which the servo information is written is incorporated into the present disk device. Furthermore, as detailed below,
The write control circuit 55 includes one that changes the level of the write current and one that changes the frequency of the write current. FIG. 11 shows the radius r of the disk 3 as a parameter.
This figure shows the relationship between the recording current 1 and the reproduction output. As shown in the graph, at the radius of
As the recording current (2) is increased, the reproduction output gradually increases; however, when the current (2) reaches a saturation level, and the recording current (2) is subsequently increased, the reproduction output tends to gradually decrease. The slope of the characteristic curve before saturation is steeper than the slope of the characteristic curve after saturation, and the direction of the slope is different1.In this way, the slope of the characteristic curve before and after saturation is steeper than that of the characteristic curve after saturation. Since the direction of the gradient is different, the write control circuit in the recording/reproducing system depends on whether the range of the recording current I used when the reproduction output level is constant is before saturation or after saturation. The method of controlling the recording current (2) by 55 is different. FIG. 12 shows a case where the recording current (2) is controlled in the range after saturation, and in this case, the level of the recording current (2) is increased as it goes to the outer circumference of the disk 3. The illustrated example is
Although the case where the current ■ is gradually increased in four steps is shown, it is not limited to this, but it is also possible to have a configuration in which it is increased gradually in an appropriate number of steps, or continuously in a linear or curved manner. . On the other hand, FIG. 3 shows a case where the recording current T is controlled in the range before saturation, and in this case, the level of the recording current T is gradually lowered toward the outer periphery of the disk 3. In this case as well, it is of course possible to change the recording current (2) stepwise or continuously. Note that before saturation, as shown in Figure 11, the slope of the characteristic curve is steeper than after saturation, so the variation tends to be larger, but the current The overall level is low, so efficiency is good. 14 to 15 show that when servo information is written to berth 1 by a signal by the write control circuit 55 of the recording/reproducing system shown in FIG. This figure shows a configuration in which the playback output level is kept constant by changing it appropriately. FIG. 14 shows the relationship between the recording frequency f of the Haas 1 signal and the reproduction output using the radius r of the disk 33 as a parameter. The characteristic curves at each radius show a tendency for the reproduction output to gradually decrease as the recording frequency increases. Therefore, when writing servo information to the disk 3 using a burst signal, the reproduction output can be kept constant by recording while decreasing the recording frequency f from the outer circumference to the inner circumference of the disk 3, as shown in FIG. It is possible to do so. When the recording frequency is changed as a function of the radius r of the disk 3 in this way, it may be changed in an appropriate number of steps, or it may be changed continuously along a straight line or a curve. As described in detail, according to the present invention, since the reproduction output of servo information becomes constant, it is possible to improve the positioning accuracy of the disk device. Particularly, when servo information is subjected to analog-to-digital conversion processing to position the head, the processing resolution can be improved, and the accuracy of head positioning can therefore be improved. Furthermore, when servo information is recorded as a signal to berth 1, by making the playback output constant regardless of the radial position of the disk, the dynamic range of servo information processing is expanded, which improves head positioning accuracy. It becomes possible to improve the Although specific embodiments of the present invention have been described in detail above, the present invention should not be limited only to these specific examples, and various modifications may be made without departing from the technical scope of the present invention. Of course, this is possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing one example of the disk device of the present invention, FIG. 2 is a schematic cross-sectional view taken along the x and -X lines in FIG. 1,
Fig. 3 is a side view of the device shown in Fig. 1, Fig. 4 is a block diagram schematically showing the overall drive control circuit of this device, and Fig. 5 is a diagram showing the configuration of the recording surface of the disk 3. Figure, Figure 6 (
8) and (b) are explanatory diagrams showing the principle of the Intexverse (HE servo system, Figure 7 is an explanatory diagram showing an example of the embedded servo system, and Figures 8 (a) and (1)) and ( (2) is an explanatory diagram showing reproduction servo information in each case of on-track, outer off-track, and inner off-track in the method shown in Fig. 7, and Fig. 9 shows writing with a constant recording current. Fig. 10 is a graph diagram showing the relationship between the tisf radius and the playback output when Figures 12 and 13 are graphs showing the relationship between the recording current and the playback output using the radius r of the disk 3 as a parameter, respectively after saturation and in order to keep the playback output constant. A graph showing how the recording current is changed in the range of saturation Mif.
Figure 15 is a graph showing the relationship between the recording current frequency f and the playback output with the parameter . FIG. 2 is a graph diagram showing a mode in which the (Explanation of symbols) 3: Magnetic disk 4: Carriage] 1: Magnetic head 31: Track 4: Servo information Patent applicant Rico Co., Ltd. - Figure 5 Figure 6 Tolerance Figure 7 Figure 8 Figure 11 Recording Current Fig. 12 Fig. 13 Fig. 14 f, f2 f3 f4 Recording frequency Fig. 15 Hu 1 r1r2r3rq r+
rz r3r4 disk radius
disk radiustask radius

Claims (1)

[Scope of Claims] 1. A disk device comprising a disk that is driven and rotated at a predetermined speed and is capable of recording information, and a writing/reading means that writes information to the disk and reads information recorded on the disk, A plurality of concentric tracks are formed on the disk, and embedded servo information indicating the position of each track is recorded corresponding to each track, and the embedded servo information is arranged from the inner track to the outer track. A disk device characterized in that recording is performed using a write current whose level is changed at least once over a track. 2. A disk device according to claim 1, wherein the embedded servo information is recorded with a write current that gradually increases from an inner track to an outer track. 3. A disk device according to claim 1, wherein the embedded servo information is recorded with a write current that gradually decreases from an inner track to an outer track. 4. A disk device according to claim 2 or 3, wherein the write current is changed in steps. 5. A disk device according to claim 2 or 3, wherein the write current is continuously changed.