Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
2001-02-08
2003-12-02
Huber, Paul W. (Department: 2653)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S275500
Reexamination Certificate
active
06657942
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a swing-arm type optical recording and reproducing apparatus and an optical disk applicable to the same. More particularly, the present invention relates to a swing-arm type optical recording and reproducing apparatus adapted to prevent defocus due to variations in the temperature and wavelength of illuminating light, and an optical disk which is applied to the optical recording and reproducing apparatus so that the swing arm of the optical recording and reproducing apparatus can swing stably.
2. Description of the Related Art
As shown in
FIGS. 1 and 2
, a conventional swing-arm type optical recording and reproducing apparatus
80
includes a swing arm
2
installed to pivot on a base
1
, an actuator
6
for providing a rotational driving force for the swing arm
2
, a slider
5
installed at an end portion of the swing arm
2
for scanning a track of an optical disk
20
while floating, due to a dynamic air pressure, on the optical disk
20
supported and rotated by a spindle motor
7
, and an optical head installed at the swing arm
2
and the slider
5
in order to optically record/reproduce information.
The optical head includes a light source
11
installed on a mount
3
of the swing arm
2
, a beam splitter
12
, a photodetector
13
, and an objective lens
15
installed at the slider
5
. The beam splitter
12
changes the path of incident rays by passing or reflecting the incident rays. That is, the beam splitter
12
passes the rays entering from the light source
11
to direct the rays toward the objective lens
15
, and reflects the rays entering from the objective lens
15
to direct the rays toward the photodetector
13
. The photodetector
13
detects an information signal recorded on the optical disk
20
and a track error signal.
In the swing-arm type optical recording and reproducing apparatus
80
, the swing arm
2
is swung by the driving force of the actuator
6
in a radial direction of the optical disk
20
. At this time, a beam L, having passed through the beam splitter
12
after being emitted from the light source
11
, is reflected from a reflecting member
14
installed at the end portion of the swing arm
2
. A reflected beam M enters and is converged by the objective lens
15
installed at the slider
5
, and is focused on a recording surface of the optical disk
20
. Subsequently, the beam reflected from the optical disk
20
travels toward the beam splitter
12
via the objective lens
15
and the reflecting member
14
, and is reflected toward the photodetector
13
from the beam splitter
12
. The photodetector
13
receives incident light, and detects the information signal and the track error signal of the objective lens
15
.
In the optical recording and reproducing apparatus
80
, the focus position of a beam spot is adjusted by the floatation of the slider
5
due to the dynamic air pressure, thus a separate focusing servomechanism function is not performed. Therefore, in the optical head, there is no focusing servomechanism to correspond to a defocus amount representing a degree of variation in a focus position of a beam spot due to temperature or wavelength variations. Since, in the conventional optical recording and reproducing apparatus
80
, a wavelength of the beam varies with temperature variations within about ±15 nm, the optical head must be configured so that the defocus amount of the optical head can be sufficiently small with respect to the wavelength variations of about ±15 nm for stable recording and reproducing.
Furthermore, the conventional optical disk
20
employed in the above swing-arm type optical recording and reproducing apparatus
80
has a structure shown in FIG.
3
. Referring to
FIG. 3
, an optical disk
20
includes a substrate
21
provided with a spiral groove forming pits
24
on a surface thereof, and a protective layer
23
provided on the substrate
21
. In the protective layer
23
, recessed grooves
23
a
face the slider
5
and correspond to the pits
24
.
The protective layer
23
has a thickness of about 50 to 100 nm, and a depth of the recessed grooves
23
a
is about 130 nm. Since the recessed grooves
23
a
are formed, a floatation height of the slider
5
is about 20 to 100 nm. Thus, there is a problem of unstable movement of the slider
5
.
Furthermore, since the light source
11
and the photodetector
13
are installed on the mount
3
, the light beam reflected from the optical disk
20
directly passes through air while returning to the photodetector
13
Thus, there is a further problem of significant light loss along the optical path.
Still further, since the focusing servochanism function is not performed, when defocus representing the degree of variation in the focus position due to variations in ambient temperature and variations in the wavelength of the light of the light source occurs, significant errors in the recording/reproducing of information may occur.
Additionally, as a recording density of the optical disk
20
becomes denser, the optical recording and reproducing apparatus
80
requires a mechanism for performing precise servo tracking of the slider
5
so that an optical spot formed on the optical disk
20
can be precisely focused. However, the conventional optical recording and reproducing apparatus
80
performs servo tracking with the actuator
6
, which drives the swing arm
2
without a separate actuator for driving the slider
5
independently. Thus, the optical recording and reproducing apparatus
80
is problematic because it is difficult to control the slider
5
precisely.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an optical disk which can be applied to a swing-arm type optical recording and reproducing apparatus adapted to minimizing variations in the floatation height of a slider floated by a dynamic air pressure.
It is another object of the present invention to provide a swing-arm type optical recording and reproducing apparatus having an improved structure capable of restraining the amount of defocus due to variations in ambient temperature and the wavelength of the light of a light source.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and, in part, will be obvious from the description, or may learned by practice of the invention.
The foregoing objects of the present invention are achieved by providing an optical disk applicable to a swing-arm type optical recording and reproducing apparatus, which is rotatably installed on a spindle motor so that information can be recorded on or reproduced from the optical disk by a slider of the optical recording and reproducing apparatus. The slider moves while floating at a predetermined height due to a dynamic air pressure in order to reduce variations in the floating height of the slider. The optical disk includes a substrate having an information recording surface for recording and reproducing an information signal, and a protective layer provided on the information recording surface. The protective layer has a flat even surface that faces the slider.
The above objects of the present invention may also be achieved by providing a swing-arm type optical recording and reproducing apparatus including a swing arm installed in order to be pivoted in a radial direction of an optical disk by a driving source; a suspension with one end fixed to the swing arm for elastically biasing the other end thereof; a slider installed on a surface of the end portion of the suspension facing the optical disk; and an optical head installed at the swing arm and the slider for recording and reproducing information. The optical head restrains defocus due to variations in ambient temperature and variations in the wavelength of the light of a light source, and includes a light source provided at the swing arm for emitting light of a predetermined wavelength; an optical path changing unit provided in the optical path of the light emit
Cho Kun-ho
Jang Dong-seob
Jung Seung-tae
Kim Dae-sik
Lee Chul-woo
Huber Paul W.
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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