Optical: systems and elements – Lens – With support
Reexamination Certificate
2003-06-04
2004-07-13
Mack, Ricky (Department: 2873)
Optical: systems and elements
Lens
With support
C359S823000, C359S814000
Reexamination Certificate
active
06762891
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical pickup device for recording or reproducing signals in a disk such as a compact disk (CD), a minidisk (MD) or a digital versatile disk (DVD)
2. Description of the Related Art
An optical pickup device includes a lens holder, a base member, an optical chassis, a tilt angle adjusting mechanism, a cover, a first stopper and a second stopper. An objective lens is attached to the lens holder. The base member holds the lens holder and has an electromagnetic drive mechanism for driving the lens holder in a focusing direction and in a tracking direction. A light-emitting device and a light-receiving device are attached to the optical chassis. The tilt angle adjusting mechanism couples the base member with the optical chassis and has a function of adjusting the tilt angle of the objective lens. The cover encloses the lens holder and has an opening for exposing the objective lens therefrom. The first stopper limits the movable range of the lens holder in the focusing direction. The second stopper limits the movable range of the lens holder in the tracking direction.
FIG. 7
is a schematic perspective view showing the optical chassis and so on for use in such an optical pickup device in the related art.
FIG. 8
is an exploded perspective view showing the base member, the lens holder and the cover.
FIG. 9
is an explanatory view of the main portion of the tilt angle adjusting mechanism.
FIG. 10
is a schematic longitudinal sectional front view of the same device.
An optical chassis
10
in
FIG. 7
is reciprocated in the radial direction of a disk along a not-shown guide shaft. In the optical chassis
10
, a frame portion
12
is formed like a rib so as to enclose a beam passage port
11
. A mounting screw insertion hole
13
a
is provided at a place in the front end portion of the frame portion
12
, and adjustment screw insertion holes
13
b
and
13
b
are provided at two (left and right) places in the rear end portion of the frame portion
12
. The reference numeral
14
a
represents a mounting screw, and
14
b
represents an adjustment screw. A coil spring
14
can be fitted to the mounting screw
14
a
. In addition, reception surfaces
15
of flat slopes are formed at three places of the frame portion
12
so as to fall away toward the inside of the optical chassis
10
.
A base member
20
in
FIG. 8
has threaded holes
23
a
and
23
b
in the lower plate portion
22
having the beam passage port
21
. The threaded hole
23
a
is disposed at one place on the front side of the lower plate portion
22
while the threaded holes
23
b
are disposed at two (left and right) places on the rear side thereof (one of the threaded holes on the rear side is not shown in the drawing). In addition, protrusions
25
each having an end surface formed into a curved surface are disposed at other three places. Further, the base member
20
has a pair of upright piece portions
24
and
24
, a support shaft
26
and a pair of protruding portions
27
and
27
. The pair of upright piece portions
24
and
24
are disposed symmetrically to extend upward from the width-direction opposite sides of the lower plate portion
22
. The support shaft
26
extends upward from the lower plate portion
22
. The pair of protruding portions
27
and
27
are disposed on the opposite sides of the support shaft
26
so as to put the support shaft
26
there between. Magnets
28
are disposed to overlap the inner surfaces of the pair of upright piece portions
24
and
24
respectively.
A lens holder
40
in
FIG. 8
has an objective lens
41
and coils
42
and
43
, which are disposed on the left and right opposite sides and the lower side of the objective lens
41
respectively. Then, a hole
44
provided in the lens holder
40
is fitted to the support shaft
26
of the base member
20
slidably axially and rotatably circumferentially, and openings
45
and
45
on the opposite sides of the hole
44
are loosely fitted to the protruding portions
27
and
27
of the base member
20
respectively. In addition, the lens holder
40
includes a not-shown magnetic substance. The magnetic substance suffers the attraction effect of the magnets
28
and
28
on the left and right sides of the base member
20
so that the lens holder
40
can be held floating in an axially intermediate portion of the support shaft
26
.
A cover
50
in
FIG. 8
is attached to the optical chassis
10
(see
FIG. 7
) coupled with the base member
20
mounted with the lens holder
40
. Thus, the cover
50
encloses the lens holder
40
. In addition, the cover
50
has an opening
51
for exposing the objective lens
41
therefrom.
In the optical pickup device obtained by installing the optical chassis
10
, the base member
20
, the lens holder
40
and the cover
50
as shown in
FIGS. 7 and 8
, the electromagnetic drive mechanism for driving the lens holder
40
in the focusing direction and the tracking direction includes the pair of upright piece portions
24
and
24
and the magnets
28
and
28
of the base member
20
having a function as a yoke, and the coils
42
and
43
provided in the lens holder
40
.
On the other hand, the tilt angle adjusting mechanism having a function of adjusting the tilt angle of the objective lens includes the mounting screw
14
a
to which the coil spring
14
has been fitted, the adjustment screws
14
b
and
14
b
, the mounting screw insertion hole
13
a
and the adjustment screw insertion holes
13
b
and
13
b
of the optical chassis
10
and the threaded holes
23
a
and
23
b
of the base member
20
forming screw fixation portions, the reception surfaces
15
of the optical chassis
10
and the protrusions
25
of the base member
20
. The base member
20
is coupled with the optical chassis
10
by the tilt angle adjusting mechanism. To adjust the tilt angle of the objective lens by means of the tilt angle adjusting mechanism, the mounting screw
14
a
having the coil spring
14
fitted thereto is inserted into the mounting screw insertion hole
13
a
of the optical chassis
10
from below, and screwed down to the threaded hole
23
a
of the base member
20
as shown in FIG.
10
. In addition, the adjustment screws
14
b
are inserted into the adjustment screw insertion holes
13
b
of the optical chassis
10
from below, and screwed down to the threaded holes
23
b
of the base member
20
. Thus, the three protrusions
25
of the base members
20
overlap the three inclined reception surfaces
15
of the optical chassis
10
respectively. An overlapping surface
25
a
of each protrusion
25
with the corresponding reception surface
15
is a curved surface as shown in FIG.
9
. Accordingly, when the two adjustment screws
14
b
screwed down to the threaded holes
13
b
are rotated forward or backward, the base member
20
is swung around two axes perpendicularly to each other. Thus, it is possible to adjust the tilt angle of the objective lens
41
in the lens holder
40
held by the base member
20
.
As can be understood from
FIG. 10
, the movable range of the lens holder
40
in the focusing direction is limited by a first stopper
61
constituted by a stopper surface
29
formed out of the upper surface of the lower plate portion
22
of the base member
20
and the inner surface of the cover
50
. That is, the lens holder
40
can be displaced in the focusing direction between the position where the lens holder
40
abuts against the stopper surface
61
and the position where the lens holder
40
abuts against the inner surface of the cover
50
. On the other hand, the movable range of the lens holder
40
in the tracking direction is limited by a second stopper constituted by the protruding portions
27
of the base member
20
which can engage with the opening walls of the openings
45
of the lens holder
40
. That is, the lens holder
40
can be displaced in the tracking direction between the position where the opening walls of the openings
45
abut against one-side ends of the protrudin
Funai Electric Co. Ltd.
Mack Ricky
Morgan & Lewis & Bockius, LLP
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