Dynamic information storage or retrieval – Dynamic mechanism subsystem – Specific detail of storage medium support or motion production
Reexamination Certificate
1996-06-27
2001-10-16
Miller, Brian E. (Department: 2652)
Dynamic information storage or retrieval
Dynamic mechanism subsystem
Specific detail of storage medium support or motion production
Reexamination Certificate
active
06304543
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to disk apparatuses and, more specifically, to disk apparatuses which write information to a disk-shaped recording medium and/or read information therefrom by using an optical head while rotating the disk-shaped recording medium.
2. Description of the Related Art
A conventional disk apparatus, which is specifically a CD-ROM apparatus, will be hereinafter described.
FIG. 6
is a plan view of a CD-ROM apparatus that was proposed by the present assignee in Japanese Unexamined Patent Publication No. Hei. 7-254202.
FIG. 7
is a partial sectional view taken along line VI—VI in FIG.
6
.
FIG. 8
is a sectional view of a 120-mm-diameter CD-ROM disk (hereinafter referred to simply as “disk”) that is used in the CD-ROM apparatus concerned.
A disk
30
is shaped such that a 15-mm-diameter opening
30
a
is formed at a central portion of a 120-mm-diameter circular plate. An area from the perimeter of the opening
30
a
to a 50-mm-diameter circle is a non-recording area
30
b
, and an area from the 50-mm-diameter circle to a 116-mm-diameter circle is a recording area
30
c
. In the non-recording area
30
b
, an area from the 15-mm-diameter circle to a 33-mm-diameter circle is a clamping area
30
d
that is used for a CD-ROM apparatus
1
to support the disk
30
.
The CD-ROM apparatus
1
is generally composed of a chassis assembly
2
and a movable assembly
3
that is held by the chassis assembly
2
so as to be movable in directions X
1
and X
2
. The movable assembly
3
is provided with a disk supporting and rotating means
4
for supporting and rotating the disk
30
which means is composed of a rotor unit
4
a
and a stator unit
4
b
. The movable assembly
3
further includes an optical head
5
for reading information from the disk
30
, and an optical head moving means
6
for moving the optical head
5
in the radial direction of the disk
30
.
The disk supporting and rotating means
4
has a configuration including a known radial-gap-type spindle motor. The rotor unit
4
a
has a rotary shaft
7
, a case body
8
, a turn table
9
, and an annular rotor magnet
10
. The stator unit
4
b
has a bearing unit
11
, and a stator coil
14
that is constituted of a core
12
and a winding
13
that is wound on the core
12
. In the spindle motor, when the stator coil
14
is energized while being controlled by a rotation control means (not shown), it exerts magnetic drive force on the rotor magnet
10
, so that the rotor unit
4
a
is rotated.
The case body
8
and the turn table
9
are integral with each other and fixed to the rotary shaft
7
. A disk support portion
9
a
of the turn table
9
, which portion is about 15 mm in radius, supports the disk
30
while contacting with its clamping area
30
d
. A rotor magnet accommodating portion
8
a
of the case body
8
, which portion is about 13 mm in radius, accommodates the annular rotor magnet
10
.
The optical head
5
is required that a lens portion
5
a
be movable to a location that is opposed to the inner border of the recording area
30
c
of the disk
30
which border is 25-mm apart from the rotation center of the disk
30
. On the other hand, to prevent an end
5
b
of the optical head
5
on the side of the disk supporting and rotating means
4
from contacting the rotor unit
4
a
of the means
4
, the outer dimensions of the optical head
5
should be such that the distance from the lens portion
5
a
to the end
5
b
is shorter than about 12 mm, which is the distance 25 mm from the disk rotation center to the lens portion
5
a
minus the radius 13 mm of the rotor unit
4
a.
In the disk apparatus
1
, as shown in
FIG. 7
, the rotor magnet accommodating portion
8
a
of the disk supporting and rotating means
4
and the optical head
5
are located side by side in the disk radial direction. Therefore, the dimensions and the shape of each of the disk supporting and rotating means
4
and the optical head
5
are so restricted as to avoid interference therebetween.
That is, the radius p of the rotor magnet accommodating portion
8
a
of the rotor unit
8
and the distance q between the lens portion
5
a
and the end
5
b
of the optical head
5
should satisfy a relationship
p+q<25 mm.
As for the disk supporting and rotating means
4
, the diameter of the rotor unit
4
a
cannot be made large because of the limitation on the diameter of the rotor magnet
10
. Therefore, the moment of the magnetic drive force of the disk supporting and rotating means
4
is relatively small, which is disadvantageous in increasing the rotation speed. In particular, in thinner CD-ROM apparatuses (for notebook-type computers) which should employ a 5-V drive voltage, the moment of the magnetic drive force is insufficient and it takes 2 to 5 seconds to complete a CLV track search. Thus, the desired data transfer rate of 6-fold/8-fold speed is not attained. Further, in quadruple-speed CD-ROM apparatuses, the necessary rotation speed is attained by employing a 12-V drive voltage because it cannot be attained by a 5-V drive voltage, which is employed in double-speed CD-ROM apparatuses. However, the increased drive voltage causes a problem of a large power consumption. The increased drive voltage also increases the amount of generated heat and, hence, requires a stronger cooling means than in the previous cases. This is disadvantageous in reducing the size and the cost of the apparatus.
As for the optical head
5
, it is difficult to design the inside structure because the distance q between the lens portion
5
a
and the end
5
b
is so restricted that the optical head
5
does not interfere with the disk supporting and rotating means
4
when the lens portion
5
a
is moved to be opposed to the inner periphery of the disk
30
. This problem is remarkable in optical heads capable of writing, such as an optical head of a CD-R apparatus.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above problems in the art and, therefore, has an object of providing a disk apparatus which has a high degree of freedom in determining the dimensions and the shape of each of a disk supporting and rotating means and an optical head.
According to the invention, there is provided a disk apparatus comprising:
an optical head for writing and reading information to and from a disk-shaped recording medium while being opposed thereto;
optical head moving means for moving the optical head in a radial direction of the recording medium; and
disk supporting and rotating means including:
a pole-shaped portion extending along a rotation axis of the recording medium;
a rotor unit which has a rotor magnet and rotates while supporting the recording medium; and
a stator unit having a stator coil that is disposed in the vicinity of the rotor magnet,
the rotor unit including first and second protrusions extending outward from the pole-shaped portion so as to form a recess in between, the first protrusion being a portion for supporting the recording medium while contacting with it, the second protrusion being a portion for accommodating the rotor magnet, and the recess being a space which the optical head goes into when it is moved to a position corresponding to an innermost portion of the recording medium.
With the above configuration, the restrictions on the dimensions and the shape of the optical pickup and/or the disk supporting and rotating means can be reduced.
REFERENCES:
patent: 4870703 (1989-09-01), Augeri et al.
patent: 5334896 (1994-08-01), Ohsawa
patent: 5528436 (1996-06-01), Peter
patent: 7-254202 (1995-10-01), None
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Miller Brian E.
Teac Corporation
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