Dynamic optical information storage or retrieval – Dynamic mechanism optical subsystem – Optical storage medium support
Reexamination Certificate
2000-09-19
2004-09-14
Cao, Allen (Department: 2652)
Dynamic optical information storage or retrieval
Dynamic mechanism optical subsystem
Optical storage medium support
Reexamination Certificate
active
06792614
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk apparatus capable of recording and reproducing information and to a method of installing spindle motor in the optical disk apparatus.
In recent years, optical disk apparatuses which read and reproduce information on an optical disk used as a recording medium by using an optical pickup have become smaller in size and higher in performance. Portable MD players using minidiscs have become generally widespread as portable optical disk apparatuses.
A portable MD player disclosed in the Japanese Unexamined Patent Publication No. Hei 11-96747 will be described below as an example of a conventional optical disk apparatus.
FIGS. 11A and 11B
are sectional views showing the conventional portable MD player disclosed in the Japanese Unexamined Patent Publication No. Hei 11-96747. Referring to
FIGS. 11A and 11B
, the portable MD player has an outer case
101
comprising an openable upper lid
101
a
and a lower case
101
b
which rotatably holds the upper lid
101
a
.
FIG. 11A
shows a condition wherein the upper lid
101
a
is open, and
FIG. 11B
shows a condition wherein the upper lid
101
a
is closed and makes contact with the lower case
101
b.
As shown in
FIG. 11A
, a minidisc case
102
(hereafter referred to as an MD case) accommodating an optical disk
100
is loaded while the upper lid
101
a
is opened. A variety of information such as music information has been recorded on the optical disk
100
. A spindle motor
103
is disposed at the nearly central area of the lower case
101
b
. A turntable
104
, on which the optical disk
100
inside the MD case
102
is to be put and rotated, is provided at the upper portion of the spindle motor
103
.
In addition, an optical pickup
105
for reading information from the optical disk
100
accommodated in the MD case
102
and a feeding mechanism
106
for moving the optical pickup
105
in the diametric direction of the optical disk
100
are provided inside the lower case
101
b
. Numeral
107
designates a feeding shaft used as a component of the feeding mechanism
106
. This feeding shaft
107
is rotatably supported by the chassis (not shown) of the feeding mechanism
106
. The optical pickup
105
screw-engaged with the feeding shaft
107
is moved in the diametric direction of the optical disk
100
by the rotation the feeding shaft
107
.
Furthermore, electric components and electric circuits required for playing the optical disk
100
inside the MD case
102
are disposed at the lower portion of the feeding mechanism
106
inside the lower case
101
b.
In the conventional portable MD player configured as described below, the relative distance between the optical pickup
105
and the optical disk
100
is required to be set within an allowable range in order to securely read the information of the optical disk
100
. In other words, the recording face of the optical disk
100
is required to be set to have a tilt within a predetermined range (not more than a standard value) with respect to the movement axis of the optical pickup
105
. If the above-mentioned relative distance is not constant, and the focal length of the lens of the optical pickup
105
is not aligned with the recording face, the information of the optical disk
100
cannot be read properly.
Moreover, if the recording face of the optical disk
100
is not parallel but significantly tilted with respect to the movement axis of the optical pickup
105
, the laser light emitted from the lens of the optical pickup
105
is reflected by the optical disk
100
and not fed back to the lens. Therefore, the information of the optical disk
100
cannot be read accurately.
The conventional optical disk apparatus having the above-mentioned configuration causes the following problems. If the optical disk
100
mounted on the turntable
104
of the spindle motor
103
is not parallel but tilted with respect to the movement axis of the optical pickup
105
, and if the tilt is not within the allowable range, the information recorded on the optical disk
100
cannot be read accurately. For this reason, it is necessary to accurately assemble the turntable
104
on which the optical disk
100
is mounted and the feeding mechanism
106
of the optical pickup
105
at the time of assembling the conventional optical disk apparatus.
FIG. 12
is a partially sectional view showing the relationship between the optical disk
100
on the turntable
104
and the optical pickup
105
of the conventional optical disk apparatus. In the example shown in
FIG. 12
, a bracket
103
a to which the spindle motor
103
is secured is tilted with respect to a chassis
108
. As a result, the turntable
104
is assembled greatly tilted with respect to the movement axis of the optical pickup
105
.
It is provided that the disk mounting face
104
a
of the spindle motor
103
installed on the chassis
108
is tilted at angle a for example with respect to the movement axis of the optical pickup
105
in the movement direction thereof as shown in FIG.
12
. In this case, the relative distance A between the lens
105
a
of the optical pickup
105
and the recording face of the rotating optical disk
100
changes greatly, thereby greatly exceeding a predetermined allowable range (standard value) and causing a problem. The angle &agr; is an angle between the rotation center axis of the spindle motor
103
and an axis perpendicular to the movement axis of the optical pickup
105
. As a result, the focal length of the laser light from the optical pickup
105
is not aligned with the recording face of the optical disk. It thus becomes impossible to read the information of the optical disk
100
.
In addition, variations in the tilt of the rotation axis of the spindle motor
103
and variations in the height of the rotation axis thereof with respect to the recording face of the optical disk
100
are relatively large when the spindle motor
103
is smaller. Therefore, in order to decrease the variations in the tilt and height of the spindle motor
103
, it is necessary to raise the machining accuracy of the components of the spindle motor
103
or it is necessary to measure the dimensions of completed components and to select and use the components having dimensions within predetermined ranges. For example, when a specific figure is given for the tilt of the spindle motor
103
, the tilt has a very narrow allowable range of about ±0.1 degree (in all directions) in the case of the MD player. Therefore, the spindle motor
103
of the conventional portable MD player has low productivity, resulting in high cost.
SUMMARY OF THE INVENTION
To solve the above-mentioned problems, the present invention is intended to provide an optical disk apparatus wherein the tilt of a loaded optical disk is set within a predetermined range. This is attained by adjusting the relative distance between the lens of an optical pickup and the recording face of the optical disk even if the disk mounting face of a turntable is tilted with respect to the movement axis of the optical pickup and the height of the disk mounting face varies considerably because the installation position of a spindle motor is tilted with respect to a chassis. The present invention is further intended to provide a method of installing the spindle motor for use in the optical disk apparatus.
An optical disk apparatus in accordance with the present invention comprises:
reading means for reading information from a disk on which information is recorded,
movement means for moving the reading means in parallel with the recording face of the disk,
a spindle motor having a turntable on which the disk is mounted and rotated and having a bracket secured thereto,
a chassis having plural spindle motor support portions to support the bracket, on which the movement means is fixed and the reading means is movably held, and
height correction means which calculates a height, whereat the spindle motor is supported by the spindle motor support portions on the basis of the tilt and height data of the di
Matsumura Asayuki
Saito Yasuhide
Yamada Yoshihiko
Akin Gump Strauss Hauer & Feld & LLP
Cao Allen
Matsushita Electric - Industrial Co., Ltd.
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