JPH01109573A - Method for controlling number of rotation of disk - Google Patents

Abstract

PURPOSE:To approximate the number of rotation of a spindle motor to the specified number of rotation for a target position, and to speed up a seek action by applying a constant drive force to the spindle motor independently of linear speed control at the time of fast moving during a seek action. CONSTITUTION:For a fast moving of a seek action, a switching switch 6 is switched by a signal from a microcomputer 7; in case the seek action is a moving from a position on the radius of a disk toward the inner position on the radius, the said switching is to a contacting point (a) side, so that the constant drive force in the positive direction is applied to the spindle motor 1 and thus its 1 number of rotation is increased by a drive voltage +Va however, in case of moving in seek from a position on the radius of the disk toward the outer position on the radius, the switch 6 is switched to a contacting point (c) side, to impress a voltage -Vc in order to reduce the number of rotation of the spindle motor 1. Thus the number of rotation of the spindle motor 1 is approximated to the specified number of rotation for the target position.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] This invention is applicable to CD (compact disc) players, etc.
The present invention relates to a disk rotation speed control method in an optical disk device that plays back an optical disk with a constant linear velocity.

EConventional technology 1 Recording is performed on a compact disc at a constant linear velocity. Therefore, when the optical head in a CD player moves in the radial direction of the disc, the disc rotational speed, that is, the rotational speed of the spindle motor, changes depending on its position. By changing the
It is necessary to control the linear velocity to be constant.

Conventionally, as a method for controlling the disc rotation speed during song selection operation, that is, during seek operation in a CD player, Daigo FM has been used.
J (U7 seek) is a control method that does not control the spindle motor rotation speed, but controls the spindle motor drive voltage to match the rotation speed suitable for the destination after the optical head reaches the destination. is common. That is, f
: As shown in the spindle motor specified rotational speed curve diagram in Figure tS4, when moving from the disk radius R position to the disk radius R2 position, the rotational speed is changed after the position movement, as shown by the arrow.

[Problem to be Solved by the Invention 1] In the conventional disk rotation speed control method described above, when the optical head reaches the vicinity of the destination, there is a large difference between the actual rotation speed and the normal rotation speed, so the spindle motor It takes time to match the rotational speed to the normal rotational speed, which is an obstacle to performing a high-speed seek operation.

In addition, as another conventional disk rotation speed control method, it is equipped with a rotation speed detector that detects the rotation speed of the spindle motor.
There is also a method of detecting the spindle motor rotation speed and controlling the spindle motor rotation speed even during large movements, but this method requires a rotation speed detector and is expensive.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks and provide a disk rotation speed control method that can realize high-speed seek at low cost without adding a special mechanism such as a rotation speed detector to the spindle motor. .

[Means for Solving the Problems 1] The method of the present invention applies a constant driving force independent of linear velocity control to the spindle motor during a large movement during a seek operation.

[Function] In the case of a seek operation in which the disk moves from the outer circumferential side to the inner circumferential side, during the large movement period (7th seek) in the seek operation, the spindle motor is given constant drive in the positive direction independent of linear velocity control. Add force.

Further, in the case of a seek operation that moves from the inner circumferential side to the outer circumferential side of the disk, a driving force in the opposite direction is applied. If the driving force applied to the spindle motor is in the forward direction, the spindle motor is accelerated, and if the driving force is applied in the opposite direction, the spindle motor is decelerated. As a result, the spindle motor rotation speed at the time the optical head reaches the destination approximates the normal spindle motor rotation speed at the destination, and the opening time during seek while applying the tracking servo is shortened. High-speed seek is achieved.

[y! , Embodiment] FIG. 1 shows an embodiment of the present invention, and is a block diagram of a disk rotation speed control device. In the figure, 1 is a spindle motor, 2 is an optical disk recorded at a constant linear velocity,
3 is an optical head.

This disk rotational speed control device is provided with a three-contact changeover switch 6 between a normal linear velocity controller 24 and a driver 5, and two contacts of this changeover switch 6 are
A positive spindle motor drive voltage (+Va) and a negative spindle motor drive voltage (-Vc), which are independent of the linear velocity fundra 4, are applied to e. In the example, spindle motor drive voltage (10 Va) + (-Vc)
is variable, but may be fixed. Further, numeral 7 indicates a microcomputer that controls the switching operation of the changeover switch 6, and 8 indicates other circuit sections for signal detection, signal processing, system control, etc.

In the above configuration, in the normal playback state, the changeover switch 6 is in the contact position, and the spindle motor 1 is driven under the control of the linear velocity controller 4. A linear velocity controller 4 controls the spindle motor to maintain a constant linear velocity based on a detection signal from the disk surface. However, during a large movement during a seek operation, the microcomputer 7
The changeover switch 6 is switched to contact A or contact A by a signal from . For a seek operation that moves radially inward from a certain point on the disk radius, contact point a
ffllll, that is, switch to the spindle motor drive voltage side of +Va, and apply a constant positive driving force to the spindle motor with this +Va drive voltage (Figure 2 (A)).
), increase the spindle motor rotation speed (see Figure 2 (b)). In FIGS. 2(A) and 2(B), T indicates the start time of the seek operation +511, and T2 indicates the time of arrival near the destination (time of completion of the large movement). When the optical head reaches the vicinity of the destination, the switching switch 6 is switched to the contact position by a signal from the microcomputer 7, and the linear velocity controller 24 returns to the normal linear velocity control, allowing accurate linear velocity control. At this time, the spindle motor rotation speed increases in parallel with the movement of the optical head to approximate the specified destination rotation fiN. That is, in FIG. 3, the spindle motor rotation speed changes in a curve that approximates the normal spindle motor rotation speed curve, as indicated by the arrow, and becomes close to the specified rotation speed at the position R2 near the destination. Therefore, the follow-up seek by the tracking servo can be done in a short time.

In addition, when seeking outward in the radial direction from a certain point on the disk radius, switch the changeover switch 6 to contact C, apply a voltage of -Vc to the spindle motor 1, brake the spindle motor 1, and increase the rotation speed. Reduce. Thereby, the spindle motor rotation speed is approximated to the specified rotation speed of the destination.

In addition, the voltage applied to the spindle motor during large movements is
The voltage value may be changed depending on the seek start position. Further, the applied voltage may be gradually increased or decreased during the large movement, so that the change closely approximates the spindle motor normal cycle number curve by mm.

[Effects of the Invention] As explained above, according to the present invention, when a large movement occurs during a seek operation, a constant driving force is applied to the spindle motor independent of linear velocity control, so the spindle motor rotational speed is adjusted to match the large movement. It is now possible to approximate the specified rotation speed at the destination by changing the rotation speed at the same time, making it possible to achieve high-speed seek at low cost without the need to add special mechanisms such as a speed detector to the spindle motor. We were able to.

[Brief explanation of the drawing]

Figures 1 to 3 illustrate one embodiment of the present invention.
Pt51 diagram is a diagram of the disk rotation speed control device, Figure 2 (a) is a diagram of the spindle motor drive voltage applied during large movements, and Figure 2 (b) is a diagram of changes in the number of times during large movements. ,
PIS3 diagram is the spindle motor normal rotation speed curve diagram, No. 4
The figure is also a spindle motor normal rotation speed curve diagram for explaining the conventional example. - 1... Spindle motor, 4... Linear speed controller, 6... Changeover switch, +Va, -Vc... Spindle motor applied voltage.

Claims (1)

[Claims] A disk rotation speed control method for an optical disk device that plays back an optical disk with a constant linear velocity, characterized in that a constant driving force independent of linear velocity control is applied to a spindle motor during a large movement during a seek operation. Control method.