Optical waveguides – With optical coupler – Switch
Reexamination Certificate
2002-04-12
2004-11-16
Palmer, Phan T. H. (Department: 2874)
Optical waveguides
With optical coupler
Switch
C385S006000
Reexamination Certificate
active
06819816
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an actuator, an optical fiber moving apparatus driven by the actuator and an optical switch driven by the actuator, and more particularly, to an actuator having a rough moving means using a linear moter mechanism and a micro moving means using a thrust force obtained by converting electric energy into kinetic energy.
2. Description of the Related Art
Conventionally, there are known an actuator for executing inchworm operation and an actuator driven by impact drive by using, for example, a piezoelectric element, as actuators for obtaining a thrust force by converting electric energy into kinetic energy.
The operation principle of the inchworm operation will be described here with reference to FIG.
18
. An inchworm mechanism, which is composed of bodies
41
and
42
and piezoelectric elements
43
-
1
to
43
-
3
extendable in two-axes directions, is placed on a slide surface
44
(FIG.
18
(
a
)). First, the piezoelectric element
43
-
1
extends in an upward direction orthogonal to a traveling direction by the voltage applied thereto, thereby the body
41
is lifted upward (FIG.
18
(
b
)). Next, the piezoelectric element
43
-
2
extends in the traveling direction by the voltage applied thereto (FIG.
18
(
c
)). After the piezoelectric element
43
-
2
extends to its full length, only the voltage applied to the piezoelectric element
43
-
1
, which has extended upward, is shut off, and the body
42
, which has been lifted upward, returns onto the slide surface
44
(FIG.
18
(
d
)).
Next, the piezoelectric element
43
-
3
is extended in the upward direction orthogonal to the traveling direction by the voltage applied thereto, and the body
41
is lifted upward thereby (FIG.
18
(
e
)). The voltage applied to the piezoelectric element
43
-
2
, which has extended in the traveling direction, is shut off, and the piezoelectric element
43
-
2
returns to its original length (FIG.
18
(
f
)). Finally, the voltage applied to the piezoelectric element
43
-
3
is shutoff, and the body
41
, which has been lifted upward, returns onto the slide surface
44
(FIG.
18
(
g
)). As a result, the bodies
41
and
42
moves forward in the traveling direction by the amount of expansion of the piezoelectric element
43
-
2
.
The bodies
41
and
42
can be moved in an opposite direction by applying a voltage to the piezoelectric elements
43
-
1
and
43
-
2
in a reverse sequence.
Further, there is an impact drive mechanism acting as a micro actuator mechanism, in addition to the above inchworm mechanism. The operation principle of the impact drive mechanism will be also described with reference to FIG.
19
. The impact drive mechanism is arranged such that a body
51
is joined to a body
52
through a piezoelectric element
53
. The body
51
is pressed against a slide surface
54
by the pressure force F applied thereto. (FIG.
19
(
a
)). When the piezoelectric element
53
is extended as shown in the figure by the voltage abruptly applied thereto, the body
51
begins to slide left on the slide surface
54
because the inertial force of the body
51
overcomes the friction between the body
51
and the slide surface
54
. At the same time, the body
52
also moves right on the slide surface (FIG.
19
(
b
)). Next, when the voltage applied to the piezoelectric element
53
is slowly released, the piezoelectric element
53
slowly returns to its original length. At this time, almost no inertial force is caused to both the bodies
51
and
52
because they have a small acceleration. Accordingly, the movement of the body
51
is prevented by the frictional force generated by the pressure force F between the body
51
and the slide surface
54
. As a result, the amount of movement of the impact drive mechanism, which was made when the piezoelectric element
53
extended at the beginning, is maintained, and the overall shape thereof returns to its original shape (FIG.
19
(
c
)). The repetition of this operation permits the impact drive mechanism to move in the direction of the body
51
.
The impact drive mechanism can be moved in an opposite direction by slowly extending the piezoelectric element
53
at the beginning and then by abruptly contracting it when it extends to its full length.
The actuator disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 4-360025 is known as an actuator using the above inchworm mechanism, and the actuator disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 8-266073 is known as a conventional technology using the above impact drive mechanism.
A first problem of conventional actuators resides in that they cannot move a large distance at high velocity. This is because that only an inchworm mechanism and an impact drive mechanism are mounted thereon and these mechanisms are driven making use of the micro displacement of a piezoelectric element. That is, this type of the conventional actuators are arranged as an actuator specialized in micro drive and cannot move a large distance at high velocity.
A second problem of the conventional actuators resides in that they cannot be formed in a small size. This is because that when a conventional actuator is composed of only the micro actuators such as the inchworm mechanism and the impact drive mechanism, it is impossible to move it a long distance at high velocity. To cope with this problem, it is necessary to separately provide a high velocity drive mechanism such as a voice coil motor on the high velocity drive mechanism. As a result, the overall size of the conventional actuator is increased.
Therefore, when a mechanical type optical switch is composed of an optical fiber moving body using a conventional actuator, switching cannot be carried out at high velocity or a compact optical switch cannot be realized.
SUMMARY OF THE INVENTION
Accordingly, it is a first object of the present invention for solving the problems of the conventional technology to provide a small actuator capable of moving at high velocity and making positional alignment at a pinpoint accuracy. A second object of the present invention is to provide an optical fiber moving body capable of moving at high velocity and making positional alignment at a pinpoint accuracy. A third object of the present invention is to provide a compact optical switch capable of being switched at high velocity and having a less connection loss.
To achieve the above-noted objects, the present invention adopts the following basic technical constitution.
The first aspect of the present invention is an actuator for moving a movable body by using a thrust force obtained by converting electric energy into kinetic energy, comprising: a first means for moving the movable body at high velocity for rough positioning of the movable body; and a second means for moving the movable body at low velocity for accurate positioning of the movable body.
In the second aspect of the present invention, the first means is a moving section of a linear motor having a moving section and a stationary section.
In the third aspect of the present invention, the moving section of the linear motor comprises any of a coil, a permanent magnet, and a conductive body, and the stationary section of the linear motor comprising any of a permanent magnet and a coil.
In the fourth aspect of the present invention, the second means comprises a piezoelectric element.
In the fifth aspect of the present invention, the second means is controlled by impact drive or inchworm drive using a piezoelectric element.
The sixth aspect of the present invention is an actuator for controlling positioning of a movable body, comprising:
a main body of the movable body; a pair of piezoelectric elements secured to the main body; a pair of coils secured to the pair of piezoelectric elements; a guide for guiding the main body; and a plurality of magnets disposed along the guide.
In the seventh aspect of the present invention, the main body comprises a position detecting means for detecting a position thereof.
The eighth aspect
NEC Corporation
Palmer Phan T. H.
Scully Scott Murphy & Presser
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