Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Mechanism control by the control signal
Reexamination Certificate
2000-08-31
2001-11-13
Hindi, Nabil (Department: 2651)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Mechanism control by the control signal
C369S053120, C369S053140
Reexamination Certificate
active
06317399
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a disk drive device suitable for use in a CD-ROM (Compact Disk as Read Only Memory) or the like, for example, and a method of setting a rotational speed of the disk drive device. This invention relates specifically to a disk drive device for determining or distinguishing that a disk-shaped recording medium is either an eccentric disk or an unbalance disk in a state in which the disk-shaped recording medium is being rotated at a predetermined speed. When it is determined that the disk is either the eccentric disk or the unbalance disk, a rotational speed of the disk drive device is reduced to thereby lessen the vibrations transferred to the outside and to maintain high performance against external vibrations and impact, and satisfactorily perform a recording and reproducing operations. This invention also relates to a disk drive device or the like capable of, when it is determined in a state in which a disk-shaped recording medium is being rotated at a predetermined speed, that the disk-shaped recording medium is neither an eccentric disk nor an unbalance disk, increasing its rotational speed to thereby read data at high speed.
This invention relates to a disk drive device or the like, of a type wherein when it is distinguished in a state in which a disk-shaped recording medium is being rotated at a predetermined speed, that an external vibration or impact of a predetermined level or more has occurred, its rotational speed is reduced to thereby lessen the influence of the external vibration or impact of the predetermined level or more on recording and reproducing operations.
FIG. 20
shows a principal portion of a related CD-ROM drive device. Referring to
FIG. 20
, a pair of pin support holes (not shown) is defined in both side plates
50
a
of a fixed case. A pair of pins
53
of a base unit holder
52
is inserted into their corresponding pin support holes. An elevation pin
54
is provided on side opposite to the provision of the pair of pins
53
of the base unit holder
52
. The elevation pin
54
is displaced in upward and downward directions by a base unit elevation mechanism (not shown) so that the one-end side of the base unit holder
52
moves up and down. Bosses
55
are placed in three points of the base unit holder
52
. Threaded holes
56
are defined in their corresponding bosses
55
.
A base unit
57
has a base plate
58
to which an optical pick-up unit
59
for reproducing data from a disk, a disk rotating unit
60
having a spindle motor for rotating the disk, etc. have been attached. Mounting holes
61
are respectively provided at three points of the base plate
58
. The base unit
57
is mounted to the base unit holder
52
by using mounting vises
62
with insulator
63
used as damping members composed of rubber.
FIG. 21
shows a mounting portion of the base unit
57
in a developed form. Referring to
FIG. 21
, the insulators
63
are mounted in their corresponding mounting holes
61
defined in the base plate
58
of the base unit
57
. The mounting vises
62
inserted into the holes of the insulators
63
are threadedly inserted into threaded holes
56
of the bosses
55
of the base unit holder
52
.
In the aforementioned construction, an external vibration or impact is transmitted to the base unit holder
52
through the fixed case
50
without attenuation so far. The vibration transmitted to the base unit holder
52
is transmitted to the base unit
57
through the insulators
63
for providing damping action. Thus, the external vibration and impact is attenuated and applied to the base unit
57
, so that the adverse effects of the vibration and impact thereon is lessened.
An external vibration characteristic of the base unit
57
has a resonance point at a range of 100 Hz to 120 Hz, for example, as shown in FIG.
22
.
Further, the number of revolutions of the disk ranges from 200 rpm to 500 rpm (3.3 to 8.3 Hz) at a standard speed, ranges from 800 rpm to 2000 rpm (13 to 33 Hz) at a quadruple speed, ranges from 1200 rpm to 3000 rpm (20 to 50 Hz) at a sextuple speed, ranges from 1600 rpm to 4000 rpm (27 to 67 Hz) at an octuple speed, and ranges from 2400 rpm to 6000 rpm (40 to 100 Hz) at a dodecuple speed.
When the disk is an unbalance disk and is rotated at a high speed of about 3000 rpm, a self-induced vibration having a frequency corresponding to the number of revolutions of the disk occurs. There is a problem in that this self-induced vibration is transmitted to the outside of the drive device through the base unit
57
and the insulators
63
, thus giving an unpleasant feeling to a user. Further, a problem arises in that tracking control of the optical pick-up unit
59
falls into difficulties due to this self-induced vibration, so that data cannot be reproduced from the disk.
FIG. 23
shows a transmission characteristic of each insulator
63
. When the insulator
63
is formed of butyl rubber, a resonance point f0 of the insulator
63
can be set to a range of 25 to 130 Hz. As the resonance f0 is made greater, a Q value is reduced so that an attenuatable frequency is shifted to a high frequency.
It is desirable that the resonance point of the insulator
63
is set so as to attenuate 100 to 120 Hz corresponding to the resonance point of the vibration characteristic of the base unit
57
and escape from a frequency corresponding to the number of revolutions of the disk, which is to be used. However, since the number of revolutions to be used increases as in the case of the sextuple speed, octuple speed, . . . , it is difficult to satisfy the two.
Therefore, for example, the resonance point f0 of the insulator
63
was set so as to be higher than the maximum number of revolutions of the disk and to satisfy escaping from the frequency corresponding to the number of revolutions of the disk, which is to be used. Therefore, although the problem about the aforementioned self-induced vibration can be lessened, the range of 100 to 120 Hz corresponding to the resonance point of the vibration characteristic of the base unit
57
cannot be attenuated sufficiently, thus resulting in significant reduction in the performance against an external vibration and impact.
When the number of revolutions of the disk increases, the influence of the external vibration or impact on the tracking control or the like becomes strong in general. Thus, when the vibration and impact of the predetermined level or more occur, it is considered that the number of rotations of the disk is reduced and the influence of the vibration and impact on the reproduction of data from the disk is lessened.
Therefore, an object of the present invention is to lessen vibrations transferred to the outside, maintain high performance against an external vibration and impact, and satisfactorily perform recording and reproducing operations. Another object of the present invention is to lessen the influence of an external vibration or impact of a predetermined level or more on recording and reproducing operations.
SUMMARY OF THE INVENTION
A disk drive device according to the present invention, wherein a base unit provided with a disk rotating unit having a spindle motor for rotating a disk-shaped recording medium and with a head for performing at least one of recording and reproducing data into and from the disk-shaped recording medium, is mounted to a base unit holder through a damping member, comprises rotational speed control means for controlling the rotation of the spindle motor to thereby control a rotational speed of the disk-shaped recording medium to a set value; disk distinguishing means for determining, in a state in which the disk-shaped recording medium is being rotated, whether the disk-shaped recording medium is an eccentric disk or an unbalance disk; and rotational speed setting means for, when the disk distinguishing means has determined the disk-shaped recording medium as the eccentric disk or the unbalance disk, changing the set value to a second rotational speed slower than the first rotational speed in a state in which the di
Arai Takafumi
Kitaru Katsunori
Kokubo Wataru
Kunishima Takeshi
Ohtani Hisao
Hindi Nabil
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Sony Corporation
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