Dynamic information storage or retrieval – Dynamic mechanism subsystem – Having power driven transducer assembly
Reexamination Certificate
2001-02-08
2003-07-15
Psitos, Aristotelis M. (Department: 2653)
Dynamic information storage or retrieval
Dynamic mechanism subsystem
Having power driven transducer assembly
C369S253000, C369S044160, C359S814000, C359S824000
Reexamination Certificate
active
06594223
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lens driving apparatus for a disk player which optically writes/reads information to/from a disk-shaped recording medium such as a compact disk or an optical disk.
2. Description of Related Art
Conventionally, a lens driving apparatus
1
for a disk player for reproducing information recorded on an optical disk such as a CD or a DVD has been known. In order to read information recorded on an optical disk accurately, the lens driving apparatus
1
for a disk player performs a focus control for controlling a distance between an information recorded surface of the optical disk and an objective lens with respect to warping or deflection of the optical disk, and a tracking control for follow-up controlling the objective lens with respect to the eccentricity of an information track of the optical disk. The structure of the lens driving apparatus
1
for a disk player will be described with reference to FIG.
1
.
A pick-up device
1
comprises: a plate-shaped actuator base
4
including yokes
3
provided so as to be opposed to each other to which a pair of magnets
2
are fixed respectively; a movable portion
7
which is movably supported, via four supporting wires
6
a
-
6
d
, by a supporting base
5
which is fixed to a side surface of the actuator base
4
by, e.g., a screw (not shown); a box-shaped actuator cover
14
for protecting the movable portion
7
, which is made of a metal plate or a resin and which includes an opening hole
14
A for an objective lens
8
in a top portion thereof; and a pick-up body (not shown) for containing optical components such as a light source, a collimator lens, and a beam splitter. The movable portion
7
comprises: a lens holder
10
containing the objective lens
8
and having four fixed arms
9
which protrude in tracking directions; a focus coil
11
wound around the body of the lens holder
10
; and four D-shaped tracking coils
12
which are fixed to the respective side surfaces of the lens holder
10
respectively opposing to the magnets
2
. The movable portion
7
is supported to be movable with respect to the actuator base
4
by providing the four fixed arms
9
of the lens holder
10
in the supporting base
5
and fixing the four fixed arms
9
to the four supporting wires
6
a
-
6
d.
The four supporting wires
6
a
-
6
d
are used to movably support the movable portion
7
and used also as a connecting line for supplying a driving current to the focus coil
11
and the four tracking coils
12
. Therefore, each of the four supporting wires
6
a
-
6
d
is made of an elastic member with a high conductivity.
One end of the focus coil
11
wound around the body of the lens holder
10
is connected to, for example, the supporting wire
6
a
, and the other end of the focus coil
11
is connected to the supporting wire
6
b
. Thus, by supplying a focus driving current to the two supporting wires
6
a
and
6
b
of the supporting base
5
, the movable portion
7
is driven in a focus direction.
The four tracking coils
12
which are fixed to the respective side surfaces of the lens holder
10
are serially connected by using the two supporting wires
6
c
and
6
d
and a wiring member
13
. More specifically, one supporting wire
6
c
is connected to a line end of one of the two tracking coils
12
which are fixed to one side surface of the lens holder
10
and which are serially connected with each other, and the other supporting wire
6
d
is connected to a line end of one of the two tracking coils
12
which are fixed to the other side surface of the lens holder
10
and which are serially connected with each other. The line ends of the other tracking coils
12
are connected with each other by the wiring member
13
. Thus, the four tracking coils
12
are serially connected with respect to the two supporting wires
6
c
and
6
d
. Therefore, by supplying a tracking driving current to the two supporting wires
6
c
and
6
d
, the movable portion
7
is driven in a tracking direction.
The movable portion
7
of the pick-up device
1
is movably supported by the four supporting wires
6
as described above. Therefore, when the movable portion
7
receives a strong vibration, for example, it may move by a large distance in a focus direction, so that the objective lens
9
hits the information recorded surface of the optical disk, thereby scratching the information recorded surface. Thus, the pick-up device
1
regulates a movement in a focus direction generally by providing the actuator cover
14
.
In recent years, along with the spread of high double-speed reproduction in an optical disk driving apparatus, there has been an increased need for a higher driving force of a spindle motor, i.e., an increase in the size of the spindle motor. As illustrated in
FIGS. 2A and 2B
, the optical disk driving apparatus comprises a turntable
16
axially supported on a spindle motor
15
, and a conveying mechanism
18
for moving the pick-up device
1
in a radial direction (a direction indicated by K in the figure) of an optical disk
17
. The conveying mechanism
18
comprises: a shaft
20
for slidably supporting a pick-up body
19
on which the lens driving apparatus
1
for a disk player is mounted in the radial direction of the optical disk
17
; a rack
21
axially supported on the shaft
20
; and a transmission gear
22
axially supported on a thread motor (not shown). In the pick-up body
19
on which the pick-up device
1
is mounted, the transmission gear
22
rotates along with the rotation of the thread motor, and the rotation of the transmission gear
22
is transmitted to the rack
21
. Along with the rotation of the shaft
20
, the pick-up body
19
moves in the radial direction of the optical disk
17
.
The pick-up body
19
on which the pick-up device
1
is mounted is conveyed in an inner circumferential direction of the optical disk
17
by the conveying mechanism
18
. However, as shown in
FIG. 2B
, the pick-up body
19
cannot move beyond a position where it contacts the spindle motor
15
. On the other hand, the pick-up device
1
cannot move beyond a position where the actuator cover
14
contacts the turntable
16
. As described above, along with the spread of high double-speed reproduction in an optical disk driving apparatus, the spindle motor has been required to have a higher driving force, and the size thereof has been increasing. As a result, such an extra space that the pick-up device can approach below the turntable is diminished, thereby making it difficult to read the innermost circumference of a disk.
OBJECT AND SUMMARY OF THE INVENTION
The present invention has been made in view of the above-described problem, and an object thereof is to provide a lens driving apparatus for a disk player, which can easily approach to the innermost circumference of a disk and which can realize a reduction in size and weight thereof.
In order to solve the above-described problem, a lens driving apparatus for a disk player according to the first aspect of the present invention has such a structure that a lens holder including an objective lens, focus coils, and tracking coils fixed thereto is supported by a plurality of cantilevered wire-form elastic members, and drives the lens holder in focus and tracking directions. The wire-form elastic members include inner circumferential side wire-form elastic members and outer circumferential side wire-form elastic members which are disposed to be apart from each other in the tracking direction so as to interpose therebetween a point of application of a focus driving force generated from the focus coils. The inner circumferential side wire-form elastic members and the outer circumferential side wire-form elastic members have respectively different spring constants when deflected in the focus direction, and have respectively different distances to the point of application in the tracking direction.
A lens driving apparatus for a disk player according to the second aspect of the present invention is the le
Ishii Katsumi
Kuroki Eiji
Suzuki Jun
Perman & Green LLP
Pioneer Corporation
Psitos Aristotelis M.
LandOfFree
Lens driving apparatus for disk player having a lens holder... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Lens driving apparatus for disk player having a lens holder..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lens driving apparatus for disk player having a lens holder... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3059651