Motor rotation control device for optical disk player

Details Motor rotation control device for optical disk player Motor rotation control device for optical disk player

1998-12-22

2001-12-04

Ro, Bentsu (Department: 2837)

Electricity: motive power systems

Plural diverse motor controls

Motor-reversing

C318S260000, C318S437000, C318S565000

Reexamination Certificate

active

06326749

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Application No. 80578/1997, filed Dec. 31, 1997, in the Korean Patent Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk player, and more particularly, to a motor rotation control device for an optical disk player.
FIG. 1
is a diagram of a conventional motor rotation control device
10
. To rotate a stationary disk (not shown) at a normal speed, a system controller
100
outputs a forward acceleration signal to a motor rotation controller
102
causing a motor
104
to forwardly accelerate. When the disk is rotating at a normal speed, the system controller
100
supplies a normal driving signal to the motor rotation controller
102
causing the motor rotation controller
102
to continue rotation of the motor
104
so as to maintain a Constant Angular Velocity (CAV) or a Constant Linear Velocity (CLV) of the optical disk. If the motor
104
accelerates to an explosive (or overrun) state, the system controller
100
outputs a backward acceleration signal to the motor rotation controller causing the motor
104
to backwardly accelerate (i.e., decelerate) so as to reach a normal speed range. During operation, the motor
104
supplies motor rotation signals (including a period of rotation) to the system controller
100
.
In summary, the motor rotation controller
102
causes the motor
104
to forwardly rotate in response to a forward acceleration signal, controls the motor
104
at a CLV/CAV in response to a normal driving signal, and causes the motor
104
to rotate backwards in response to a backward acceleration signal.
FIG. 2
is a flowchart of a conventional motor rotation control process. At step
200
, the system controller
100
generates a forward acceleration signal to accelerate the motor
104
forwardly. At step
202
, the system controller
100
checks the period of the rotation, using the motor rotation signal generated from the motor
104
, and judges whether the number of rotations per unit of time of the motor
104
is greater than a number N corresponding to a forward acceleration limit speed. If the number of rotations is not greater than the number N, the process goes to step
204
and the system controller
100
continues to accelerate the motor
104
forwardly. If, in step
202
, the number of rotations is greater than the number N, the process goes to step
206
and the system controller
100
checks whether the number of rotations per unit of time of the motor
104
is less than a number M corresponding to a backward acceleration limit speed.
If, in step
206
, the number of rotations is less than the number M, the process goes to step
210
and the system controller
100
carries out normal CLV/CAV control of the motor
104
. The process then returns to step
202
. If, in step
206
, the number of rotations is not less than the number M, the process goes to step
208
and the system controller
100
generates a backward acceleration signal to accelerate the motor
104
backwardly at step
208
. The process then returns to step
202
.
The system controller
100
must continually check the rotation period of the motor
104
so as to be able to set a forward acceleration speed and a backward acceleration speed for the motor
104
. Hence, the system controller
100
must spend a lot of time checking the rotation speed of the motor
100
. Unfortunately, in the conventional motor rotation control device, while controlling the motor
100
at a CLV/CAV, the system controller
100
does not know whether the motor
104
is rotating forwardly or backwardly. Therefore, it is difficult to prevent the motor
104
from rotating backwardly during focus drop, i.e., when the RF signal from the optical pickup contains only noise and no sync signal, and degrading the performance of an optical disk player.
The system controller
100
must continually check the rotation period of the motor
104
so as to be able to set a forward acceleration speed and a backward acceleration speed for the motor
104
. Hence, the system controller
100
must spend a lot of time checking the rotation speed of the motor
100
. Unfortunately, in the conventional motor rotation control device, while controlling the motor
100
at a CLV/CAV, the system controller
100
does not know whether the motor
104
is rotating forwardly or backwardly. Therefore, it is difficult to prevent the motor
104
from rotating backwardly during focus drop, i.e., when the RF signal from the optical pickup contains only noise and no sync signal, and degrading the performance of an optical disk player.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a motor rotation control device for an optical disk player which can reduce the load of a system controller while driving a motor.
It is a further object of the present invention to provide a motor rotation control device in which a system controller is aware of the rotational direction of the motor.
These and other objects of the present invention are realized by a motor rotation control device for an optical disk player comprising a motor, a sensor sensing the rotational direction and rotational state of the motor in response to rotation signals of the motor, a motor control signal generator generating a motor control signal according to the rotational direction and rotational state of the motor, and a motor rotation controller controlling the rotation of the motor in response to the motor control signal.


REFERENCES:
patent: 4292577 (1981-09-01), Cesarz et al.
patent: 4331917 (1982-05-01), Render et al.
patent: 4339699 (1982-07-01), De Jonge et al.
patent: 4367435 (1983-01-01), Bailey et al.
patent: 4473226 (1984-09-01), Siegel et al.
patent: 5376870 (1994-12-01), Ueda et al.
patent: 5422810 (1995-06-01), Brunning et al.

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