JPH04113557A - Method for driving memory disk and memory disk - Google Patents

Abstract

PURPOSE:To easily drive the memory disk by a compact driver by detecting the magnetic pole of a magnetic layer by a hole element, controlling a switching circuit and switching the polarity of the direct current of a driving coil. CONSTITUTION:The driving coil and the hole element are faced to a memory disk 1 forming a rotor pattern 4A on the outer or inner face of a disk, the magnetic pole of the rotor pattern 4A is detected by the hole element and by switching the switching circuit, the polarity of the direct current of the driving coil is switched. By repeating the above-mentioned operation, the memory disk 1 is rotated. Thus, since the memory disk 1 itself is operated as a rotor, a driving mechanism can be simplified without requiring any complicated driving mechanism.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of driving a memory disk and a memory disk, and particularly a method of controlling the rotation of a memory disk with a compact drive mechanism and excellent response speed. and regarding memory disks therefor.

[Prior art] Technologies for recording optical signals on a transparent substrate and reading out the recorded information string by rotating the substrate include compact discs, video discs, phase change optical discs, hole punching type write-once discs, and magneto-optical discs. etc. has been established. Other known techniques include a method in which a signal is recorded in a dye layer of a disk and read out based on a change in the absorption spectrum, and a method in which a signal recorded by deformation of the recording layer is read out based on a phase difference.

By the way, as methods for reading and writing optical signals, there are a CLV method in which the distance scanned per unit time is constant, and a CAV method in which the disk rotation angle per unit time is constant.

In the CAV method, since the rotational angular velocity is constant, it is only necessary to keep the rotational speed of the rotating table or rotating shaft, and even the motor, constant, which simplifies the rotational speed control mechanism. The recording density is different near the outer periphery, so there is a drawback that the amount of information recorded on the second disk is small.

On the other hand, in the CLV method, the rotational angular velocity is changed so that it is faster near the outer periphery of the disk and slower near the inner periphery of the disk (by doing so, the scanning distance per unit time is constant, so the recording density is the same no matter where on the disk it is recorded. This makes it possible to increase the storage capacity of the disk, but on the other hand, the control mechanism for changing the rotational speed of the disk becomes complex, especially when the head moves to different parts of the disk during high-speed writing and reading. It is necessary to quickly increase or decrease the number of disk rotations according to the head position, and the time required to follow the rotational speed is shortened (because of this, the response speed and vibration characteristics of the acceleration and braking mechanisms may restrict the data transfer rate of the system). Therefore, especially in the CLV method, it is advantageous to make the inertial mass of the rotating system as small as possible, and it is also advantageous to make the rotational force transmission control mechanism as small as possible to suppress parasitic vibrations.

Conventionally, in both the CLV method and the CAV method, the method of rotating a disk is to place the disk on a rotary stand or rotating shaft connected to a motor, and to transmit the rotation of the motor to the disk.

[Problems to be Solved by the Invention] In both the CLV method and the CAV method, when these discs are used in portable devices such as a Disc Walkman or a laptop computer, the size and weight of the drive device including the drive mechanism, It is necessary to reduce power consumption as much as possible, but the conventional method of transmitting the rotation of the motor to the disk by placing a disk on a rotating shaft connected to the motor requires a drive motor, a power transmission mechanism, 9 rotation control mechanisms, and 9 rotation tables. , etc., and there was a limit to the reduction in weight per size. Furthermore, since the inertial weight of these mechanical parts is large, there is a limit to the reduction in power consumption for control.

Therefore, a method for driving a memory disk that solves the above-mentioned conventional problems and allows the memory disk to be driven with high driving force and excellent speed control accuracy using a compact drive mechanism and low power consumption. The arrival of a memory disk for this purpose was awaited.

[Means for Solving the Problems] In order to solve the above problems, in the method for driving a memory disk of the present invention, a drive coil is attached to a memory disk in which a magnetic layer made of a permanent magnet is formed on the outer surface or inside of a disc-shaped disk. The optical recording medium is rotated by arranging the Hall elements to face each other, detecting the magnetic pole of the magnetic layer with the Hall element, and controlling a switching circuit to switch the polarity of the direct current of the drive coil.

Further, the memory disk of the second invention is driven by the driving method of the first invention, and has a configuration in which a magnetic layer made of a permanent magnet is formed on the outer surface or inside of the disc-shaped disk.

The present invention will be explained in detail below with reference to the drawings. Note that hereinafter, a magnetic layer made of a permanent magnet provided on a disc-shaped disk may be referred to as a "rotor pattern." Furthermore, hereinafter, a circuit including a conductive coil pattern and a Hall element will be referred to as a "drive circuit."

The memory disk of the present invention has a reflectance change for reading and/or writing optical signals.

A rotor pattern is provided on the outer surface or inside of a disk substrate (disc-shaped disk) on which optical signals are recorded by optical path change 1 phase change, magneto-optical rotation angle change, and absorption rate change. The following ■, ■,
Method (2) is given as an example.

(2) If the disk is of the single-sided recording type, a rotor pattern is provided on the surface of the disk opposite to the surface facing the head for reading and/or writing signals.

(2) If the disc is a double-sided recording type, a rotor pattern is provided in the intermediate layer sandwiched between the front and back recording layers 1 and reflective layers.

(2) A rotor pattern is provided on the outer periphery (the outer periphery in the radial direction of the disk (outside the guide groove)) which is outside the head position for reading and/or writing signals on the disk.

In this case, the rotor pattern may be located on the surface facing the head, on the opposite surface, or inside the disk.

In the present invention, the rotor pattern is formed by a permanent magnet made of a thin plate of any ferromagnetic material or a plastic magnet. Various methods are employed to form disk circuits using these materials.

As one method, the memory disk of the present invention can be made by laminating a film or sheet made of a ferromagnetic material or a plastic magnet sheet on which a circuit pattern has been previously formed to a disk substrate. In this case, techniques for attaching a thin plate of magnetic material onto a film or sheet by methods such as pressure bonding, adhesion, PVD, plating, etc., and techniques such as etching, punching, etc. for forming the thin plate into a desired pattern are known.

As another method, the rotor pattern may be formed directly on the substrate by the PVD method.

An example of the drive circuit of the present invention is shown in FIG. When magnetic lines of force penetrate the Hall element due to the rotor pattern on the disk, a Hall voltage proportional to the magnetic flux density and power supply voltage is generated in the Hall element due to the Lorenz force, which drives the switching transistor and switches the DC current of the drive coil. .

In addition to a rotor pattern for driving, an encoder pattern for detecting rotational speed and a coil pattern for braking can be added to the disk. These auxiliary patterns can also be used as driving rotor patterns.

When a rotor pattern is created on a film or sheet, a reflective film for reading optical signals can be formed on the back surface thereof, and when a plastic magnet sheet or film is used, a reflective film for reading optical signals can be formed on the adhesive surface with the disk.

In the CLV system, the rotation speed is controlled by adjusting the drive voltage or switching timing of the drive coil by reading the optical head position or the head reading of a wappling marker attached to the disk in advance.

Since the CAV method keeps the rotational angular velocity constant, the control system is simplified.

The disk may be placed within the electric field of the external stator armature by mounting it on a suitable rotating shaft or rotating table, or by using air or magnetic levitation. In the case of levitation, guides for position control can be installed at appropriate locations.

[Function]- The method for driving a memory disk of the present invention involves arranging a drive coil and a Hall element to face a memory disk in which a rotor pattern is formed on the outer or inner surface of a disc-shaped disk, and aligning the magnetic pole of the rotor pattern with the Hall element. By detecting this and switching the switching circuit, the polarity of the DC current of the drive coil is switched. The feature is that the memory disk is rotated by sequentially repeating this process. Therefore, since the memory disk itself functions as a rotor, a complicated drive mechanism as in the prior art is not required, and the drive mechanism can be simplified.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

1 to 5 show embodiments of the present invention, and FIG. 1(a)
is a plan view of the memory disk, and FIG. 1(b) is a plan view of the memory disk.
Figure 1(c) is a side cross-sectional view taken along line B-B in Figure 1(a).
Fig. 2 is a schematic diagram showing an example of a rotor pattern of a memory disk, Fig. 3 is a perspective view showing an embodiment of the present invention, and Fig. 4 is a partially enlarged side sectional view of part 0 of b). FIG. 5 is a sectional view of a memory disk showing another embodiment of the present invention.

Example 1 Figure 1 (a) (plan view), Figure 1 (b) (Figure 1 (a)
), and FIG. 1(C) (cross-sectional view along line BB of
A memory disk 1 shown in the enlarged view of part 0 in Figure (b) was manufactured. A transparent disk substrate in which signal pits 2A were formed as irregularities on polycarbonate was prepared by an injection method, and an aluminum reflective film 3 was vapor-deposited on the surface. A polycarbonate film 4 on which a permanent magnet rotor pattern 4A shown in FIG. 2 was formed was adhered thereto, and a protective film 5 was further applied to obtain the disc 1 of the present invention shown in FIG. 1. The signal recording method was CLV. 12 indicates a spindle hole. This disk 1 was installed in a drive device as shown in FIG. 3, and was rotated by passing a DC drive current through the stator coil 7. The rotation speed was controlled based on the position signal from the optical head.

According to this embodiment, since the drive device does not include the rotor of the motor itself and the mechanical rotation transmission mechanism, the entire device can be made smaller and lighter.

Example 2 A tin-lead alloy recording layer 9A was formed by sputtering on a polycarbonate substrate 9 having guide grooves and wobbling marks for CLV control on one side. A magnetic thin plate pattern 8A extending around the outer circumference of the disk was sandwiched and adhered between the two substrates described above to obtain the memory disk 10 of the present invention (Fig. 5). This was placed on an air bearing shaft and read with an optical head. The memory disk was rotated by controlling the drive current using the generated speed signal. Since the moment of the rotation system is small, the stabilization time for rotational control accompanying movement of the optical head can be made sufficiently shorter than the stabilization time for the head position.

[Effects of the Invention] As detailed above, according to the memory disk driving method and memory disk of the present invention, the memory disk itself functions as a rotor (therefore, the memory disk can be driven by a simplified and compact driving device and driving force). At,
It can be easily driven. In addition, since the disk is directly driven, the inertial mass is small (and acceleration and deceleration can be performed effectively, so data can be transferred at high speed even when searching for random recording areas. Furthermore, the method of the present invention For example, it has excellent ability to follow changes in the rotational speed of the memory disk, making it possible to easily achieve high-speed rotation.

Therefore, according to the present invention, the recording device can be made smaller and lighter;
It is possible to reduce power consumption, increase precision and speed of recording and reproduction, and has extremely high industrial utility.

[Brief explanation of the drawing]

1 to 5 show embodiments of the present invention, and FIG. 1(a)
is a plan view of the memory disk, and FIG. 1(b) is a plan view of the memory disk.
Figure 1(c) is a side cross-sectional view taken along line B-B in Figure 1(a).
Fig. 2 is a schematic diagram showing an example of a rotor pattern of a memory disk, Fig. 3 is a perspective view showing an embodiment of the present invention, and Fig. 4 is a partially enlarged side sectional view of part 0 of b). FIG. 5 is a sectional view of a memory disk showing another embodiment of the present invention. 1.10... Memory disk, 2... Transparent disk substrate, 2A... Signal bit, 3... Aluminum reflective film, 4... Polycarbonate film, 4A.・・・
Rotor pattern, 5...Protective film, 7...
... Stator coil, 8A ... Rotor pattern, 9 ... Disk board, 12 ... Spindle hole, H4 ...
・Hall element, L43. L44... Drive coil, S41. S42...Switching transistor, R4
5, R46...Resistance. Patent applicant Ube Industries Co., Ltd. Figure 2

Claims (2)

[Claims] (1) A drive coil and a Hall element are opposed to a memory disk in which a magnetic layer made of a permanent magnet is formed on the outer surface or inside of a disc-shaped disk, and the magnetic pole of the magnetic layer is detected by the Hall element to control a switching circuit. A method of driving a memory disk, which rotates the optical recording medium by switching the polarity of a direct current of a driving coil. (2) A memory disk used in the method of claim 1, wherein a magnetic layer made of a permanent magnet is formed on the outer surface or inside of the disc-shaped disk.