JPH01277377A - Magnetic head positioning device - Google Patents

Abstract

PURPOSE:To prevent an access speed from being dropped, to omit a magnetic shield and to obtain a miniaturized and simple constitution by controlling the positioning a head carrying mechanism in accordance with the photodetecting quantity of plural photodetectors linearly arrayed in the radial direction of a magnetic disk. CONSTITUTION:A projector 16 for radiating light beams to a slit 18a in a prescribed range is fixed to a member 8 for supporting a magnetic head H, a solid state image pickup element 17 having plural photodetecting elements linearly arrayed in the radial direction of magnetic disks 1, 2 at a pitch thinner than the track pitch of the disks 1, 2 is arranged oppositely to the projector 16 and a head carrying mechanism 5 is controlled by a servo control correspondingly to the photodetecting quantity of the element 17 to position the magnetic head H on a specified track. Thereby, it is unnecessary to record servo information on a magnetic disk and the absolute positions of the magnetic head H are continuously detected to control the positioning of the magnetic head H. Consequently, the access speed can be prevented from being dropped and the miniaturized and simple constitution can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a magnetic head positioning device that is applied to hard disk drives and the like and that positions a magnetic head on an arbitrary track on a magnetic disk.

``Prior Art'' In general, the methods for positioning a magnetic head include an open-loop method using a stepping motor, which can be constructed at a relatively low cost, and a method in which servo information is recorded in advance at a specific location on a magnetic disk. Read the information and
There is a closed-loop method that controls the movement of the track strip of the magnetic head and track following, and the latter method is used in hard disk drives with a high track density.

"Problem to be Solved by the Invention" By the way, when using the closed-loop method described above, it is possible to improve access speed and track density compared to the open-loop method. Since it is occupied by servo information, this is a factor that hinders increasing storage capacity.

Therefore, we used a linear magnetic encoder that detects the amount of displacement from the origin position by recording magnetically recorded sine waves of a certain wavelength on a scale (long magnetic material) in advance and reading magnetic information from this scale. It has been proposed that a voice coil motor functioning as an actuator of a head feeding mechanism is controlled based on the output of this magnetic encoder. However, the above-mentioned magnetic encoder is of a so-called incremental type that obtains the amount of displacement from the origin position by counting its output. For example, if the current position becomes unknown due to external noise, etc. After returning to the position, the counting operation had to be repeated again, which sometimes resulted in a decrease in access speed. In addition, in the configuration in which the position of the magnetic head is detected using the magnetic encoder described above, it is necessary to provide a magnetic shield so that the magnetic encoder is not affected by the magnetic field of the voice coil motor, which reduces the size and simplification of the entire device. There was also the problem that the development of the system was hindered.

This invention was made in view of the above-mentioned circumstances, and not only does it eliminate the need to record servo information on a magnetic disk, allowing for a large storage capacity, but it also enables continuous detection of the absolute position of the magnetic head. It is an object of the present invention to provide a magnetic head positioning device which performs positioning control without reducing the access speed, and which does not require a magnetic shield and has a compact and simple configuration.

"Means for Solving Problem R" The present invention includes a head feeding mechanism that is provided on a base and reciprocates a magnetic head in the radial direction of a magnetic disk, and a head feeding mechanism that is provided on a member that supports the magnetic head and that is provided in a predetermined range. a light projector that irradiates a slit beam onto the base; and a light projector provided on the base at a position facing the projector, arranged linearly in the radial direction of the magnetic disk at a pitch finer than the track pitch of the magnetic disk. a solid-state image sensor having a plurality of light-receiving elements, and the head feeding mechanism is controlled based on an output corresponding to the amount of light received by each light-receiving element of the solid-state image sensor, and the magnetic head is positioned on a designated track. It is characterized by comprising a control means.

"Operation" According to the above configuration, the absolute position of the magnetic head is continuously detected by the solid-state image sensor at a resolution finer than the track pitch of the magnetic disk. The current position will not become unknown due to noise, etc., and the access speed will not decrease due to this. Also, since the magnetic head position is optically detected, the actuator of the head feeding mechanism can be There is no need to provide a magnetic shield around the voice coil motor, which functions as a voice coil motor, and the structure can be small and simple.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the external configuration of an embodiment of the present invention. In this figure, reference numeral 1.2 denotes magnetic disks disposed vertically at a predetermined distance apart, and these two magnetic disks 1.2 are coaxially connected by a shaft 3, and It is rotatably supported on a base 4, and is further rotationally driven by a spindle motor (not shown). Data is recorded on each magnetic recording surface of these magnetic disks 1.2 along n concentric tracks T, .about.T. Further, reference numeral H designates a magnetic head which is arranged to face each magnetic recording surface of the magnetic disk 1.2 and writes and reads data on each magnetic recording surface. The figure shows only the magnetic head H facing the upper surface of the magnetic disk 1, and the other magnetic heads are not shown.

Each of these magnetic heads H is reciprocated in parallel in the radial direction of the magnetic disk 1.2 by a head feeding mechanism 5. The head feeding mechanism 5 includes a voice coil motor 6 (see FIG. 3) fixed on the base 4, an arm 7 linearly reciprocated in the direction of the arrow shown in the figure by the voice coil motor 6, and an arm 7. The gimbals 8 are attached to the tips of the magnetic heads H and support the magnetic heads H, respectively. The voice coil motor 6 includes, as is known in boat fishing, a voice coil provided at the base end of the arm 7, a yoke placed vertically opposite to each other so as to sandwich the voice coil, and a yoke attached to the yoke. It is made up of a magnet. When a current is supplied to the voice coil, a thrust proportional to the current is generated, thereby driving the arm 7 back and forth. On the other hand, i5 is a head position detector that continuously detects the position of the magnetic head H, and is connected to a light emitter 16 attached to the lower end surface of the arm 7 and a line attached to the base 4 at a position facing the emitter 16. It is composed of an image sensor 17. As shown in FIG. 2, the projector 16 has a light emitting diode 19 housed in a case 18, and a magnetic head is mounted on the bottom surface of the case 18. ] A slit 18a is formed in a direction perpendicular to the direction of movement of the line image sensor 17 (arrow direction).
A slit beam SL having a width equal to the track pitch Tp of the magnetic disk 1.2 and the track distance is irradiated onto the magnetic disk 1.2.

The line image sensor 17 is constituted by a C0D (charge-coupled device) type -dimensional solid-state image sensor, and has (n+1) light receiving elements P, which is one more than the number of tracks n on the magnetic disk 1.2. , ~P n+1 is the same pitch as the track pitch TP of the magnetic disk 1.2,
They are arranged linearly in the radial direction of the magnetic disk 1.2.

In this case, the distance from the center line CL of the light receiving elements P1 and Pt to the center line Cut of the light receiving elements pn and Pn++ is
It is the same as the width dimension B between tracks T and -Tn on the magnetic disk 1.2. Furthermore, in the line image sensor 17, the slit beam SL coincides with the center line CL when the magnetic head H is located on the innermost track T1, and when the magnetic head H is located on the outermost track Tn. In this case, the slit beam SL is arranged to coincide with the center line CL.

Next, the circuit configuration of the above embodiment is as shown in FIG. In this figure, the line image sensor 17 is n
+1@ elementary light receiving element P, ~pnya.

The photoelectric conversion section 17a has an n+1 stage analog shift register section 17b.

Then, the slit beam S irradiated onto the photoelectric conversion unit 17a
L is converted into a voltage signal according to the amount of light received by each of the light receiving elements °P1 to pn+t, and then transferred in parallel to the shift register section 17b in synchronization with the scan timing signal supplied from the servo controller 20, Furthermore, in synchronization with the same scanning timing signal, the shift register section 17b
The signals are sequentially output from the servo controller 20 in series and supplied to the servo controller 20. The servo controller 20 detects the position of the magnetic disk I based on the sensor output of the line image sensor 17, and operates the voice coil motor 6 so that the magnetic disk H is always located on an externally designated track. Control.

In the above configuration, when the i-th track T is specified to the servo controller 20 from the outside, the servo controller 20 determines the amount of light received by the light receiving elements P and Pl+t based on the sensor output of the line image sensor 17. The current supplied to the voice coil motor 6, which functions as an actuator of the head feeding mechanism 5, is controlled so that the current is always equal, and thereby the magnetic head H is always positioned above the track T.

Note that in the above-described embodiment, the light receiving element P.

The moving direction of the magnetic head H may be detected from the increase/decrease in the amount of light received by the servo controller 20, and information regarding the moving speed of the magnetic head H may be detected in the servo controller 20 based on the position information obtained from the sensor output. By further obtaining information regarding acceleration and utilizing this information regarding velocity and acceleration for servo control, it is possible to realize positioning control with even higher accuracy. Furthermore, the above CCD
M OS fj instead of the line image sensor 17
Of course, a one-dimensional solid-state imaging device such as a line image sensor may be used.

"Effects of the Invention" As explained above, according to the present invention, the member supporting the magnetic head is provided with a light projector that irradiates a slit beam in a predetermined range, and the light projector is placed at a position facing the projector at a position that is closer to the track pitch of the magnetic disk. A solid-state image sensor is provided that has a plurality of light-receiving elements linearly arranged in the radial direction of the magnetic disk at very fine pitches, and the head feeding mechanism is controlled based on the output corresponding to the amount of light received by each light-receiving element of the solid-state image sensor. However, since a control means for positioning the magnetic head on a designated track is provided, it is no longer necessary to record servo information on the magnetic disk, and not only can a large storage capacity be realized, but also the absolute position of the magnetic head can be adjusted. is detected continuously based on the output of the solid-state image sensor, and the positioning of the magnetic head is controlled. Therefore, unlike when using a conventional magnetic encoder, the current position becomes unknown due to external noise, etc., and the access speed decreases. In addition, since the position of the magnetic head is optically detected, there is no need to provide a magnetic shield around the voice coil motor that functions as the actuator of the head feeding mechanism, as in the past. The advantage is that the structure can be small and simple.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the external configuration of an embodiment of the present invention;
Figure 2 is an enlarged perspective view of the main parts of the same embodiment;
The figure is a block diagram showing the electrical configuration of the same embodiment. H...Magnetic head, 1.2...Magnetic disk, 4...Base, 5...Head feeding mechanism, 6... Voice coil motor, 7...Arm (member), 16...Light emitter, 17...Line image sensor (solid-state image sensor), 17a...Photoelectric conversion Part, 17b... Analog shift register part, 18a
... Slit, 19 ... Light emitting diode, 20 ... Servo controller (control means)
.

Claims (1)

[Scope of Claims] A head feeding mechanism provided on a base and reciprocating a magnetic head in the radial direction of a magnetic disk; and a floodlight provided on a member supporting the magnetic head and projecting a slit beam onto a predetermined range. , a solid-state image sensor provided on the base at a position facing the light projector and having a plurality of light receiving elements arranged linearly in the radial direction of the magnetic disk at a pitch finer than the track pitch of the magnetic disk; and a control means for controlling the head feeding mechanism based on an output corresponding to the amount of light received by each light receiving element of the solid-state image sensor, and positioning the magnetic head on a designated track. A magnetic head positioning device.