U.S. patent application number 09/997480 was filed with the patent office on 2002-03-28 for ultrasonic motor and electronic apparatus equipped with ultrasonic motor.
This patent application is currently assigned to SEIKO INSTRUMENTS. Invention is credited to Iino, Akihiro, Kasuga, Masao, Suzuki, Kenji, Suzuki, Makoto.
Application Number | 20020036445 09/997480 |
Document ID | / |
Family ID | 17767702 |
Filed Date | 2002-03-28 |
United States Patent
Application |
20020036445 |
Kind Code |
A1 |
Iino, Akihiro ; et
al. |
March 28, 2002 |
Ultrasonic motor and electronic apparatus equipped with ultrasonic
motor
Abstract
There is provided an ultrasonic motor whose vibration loss is
suppressed, whose structure is miniaturized, whose production
process is simplified and which is capable of utilizing electrical
energy very efficiently. The inventive ultrasonic motor comprises a
first piezoelectric body having a first polarized portion excited
when voltage is applied and a second piezoelectric body that is
laminated with the first piezoelectric body in a body in the
longitudinal direction parallel to the polarizing direction and
having a first polarized portion at position separated from the
first polarized portion of the first piezoelectric body in the
transverse direction vertical to the polarizing direction and moves
a moving body by vibration obtained by combining stretching
vibration and bending vibration caused by distortion in the
polarizing direction of the first polarized portion of the first
piezoelectric body and the first polarized portion of the second
piezoelectric body.
Inventors: |
Iino, Akihiro; (Chiba-shi,
JP) ; Kasuga, Masao; (Chiba-shi, JP) ; Suzuki,
Makoto; (Chiba-shi, JP) ; Suzuki, Kenji;
(Chiba-shi, JP) |
Correspondence
Address: |
Bruce L. Adams
Adams & Wilks
31st Floor
50 Broadway
New York
NJ
10004
US
|
Assignee: |
SEIKO INSTRUMENTS
|
Family ID: |
17767702 |
Appl. No.: |
09/997480 |
Filed: |
November 21, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09997480 |
Nov 21, 2001 |
|
|
|
09177455 |
Oct 22, 1998 |
|
|
|
Current U.S.
Class: |
310/323.16 ;
310/323.17; 310/328 |
Current CPC
Class: |
H01L 41/0906
20130101 |
Class at
Publication: |
310/323.16 ;
310/323.17; 310/328 |
International
Class: |
H01L 041/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 23, 1997 |
JP |
9-291343 |
Claims
What is claimed is:
1. An ultrasonic motor for moving a moving body by utilizing
vibration of a vibrating body comprising: said vibrating body being
composed of piezoelectric vibrators in which a plurality of
piezoelectric bodies are laminated as a whole, wherein said
piezoelectric bodies being a first piezoelectric body having a
first polarized portion and a second piezoelectric body that is
laminated with said first piezoelectric body in the longitudinal
direction parallel to the polarizing direction and having a first
polarized portion at position separated from said first polarized
portion of said first piezoelectric body in the transverse
direction vertical to the polarizing direction; and said moving
body being moved by vibration obtained by combining stretching
vibration and bending vibration caused by vibrations of said first
polarized portion of said first piezoelectric body and said first
polarized portion of said second piezoelectric body in the
polarizing direction.
2. The ultrasonic motor according to claim 1, wherein said first
and second piezoelectric bodies have second polarized portions
further at positions corresponding to said first polarized portions
of own.
3. The ultrasonic motor according to claim 1, wherein a third
piezoelectric body which vibrates in the same phase with said
stretching vibration is laminated in a body.
4. The ultrasonic motor according to claim 1, wherein a third
polarized portion which vibrates in the same phase with the
stretching vibration is provided between said first polarized
portion of said first piezoelectric body and said first polarized
portion of said second piezoelectric body at least in either one of
said first piezoelectric vibrator and said second piezoelectric
vibrator.
5. The ultrasonic motor according to claim 1, wherein said moving
body is abutted to said laminated piezoelectric vibrator in the
horizontal direction.
6. The ultrasonic motor according to any one of claims 1 through 4,
wherein a plurality of said laminated piezoelectric vibrators are
abutted to one moving body.
7. An electronic apparatus equipped with the ultrasonic motor
comprising the ultrasonic motor described in any one of claims 1
through 6.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to an ultrasonic motor in
which piezoelectric vibrators are laminated in a body in the
longitudinal direction in parallel to its polarizing direction and
more particularly to an improvement of an ultrasonic motor
utilizing longitudinal vibration of the piezoelectric vibrators and
an electronic apparatus equipped with the ultrasonic motor.
[0002] An ultrasonic motor utilizing vibration of piezoelectric
vibrators is drawing attention lately in the field of
micromotors.
[0003] An ultrasonic motor utilizing stretching vibration and
bending vibration of rectangular piezoelectric vibrators (dual-mode
vibrator) in particular is used in various uses because it is
capable of moving an object linearly or rotably by combined
vibration of those two vibrations. An ultrasonic motor of a type in
which piezoelectric bodies are layered is also used for the use
requiring a high output (see Japanese Patent Laid-Open No. Hei.
7-184382).
[0004] FIG. 16 shows an ultrasonic motor of a type in which
rectangular plate-like piezoelectric bodies are layered. A basic
vibrator of the ultrasonic motor comprises piezoelectric bodies 61,
62, 63, 64, 65 and 66 which are polarized in a predetermined manner
so as to vibrate in the dual mode and are layered in the polarizing
direction, output fetching members 71, 72, 73, 74, 75 and 76
provided on edge portions 61a, 62a, 63a, 64a, 65a and 66a provided
in the direction vertical to the polarizing direction of the
piezoelectric bodies 61 through 66 and electrodes (not shown)
provided on the both sides of the piezoelectric bodies 61 through
66. The six piezoelectric vibrators, i.e., the piezoelectric bodies
of two rows arrayed in the horizontal direction and stacked in
three layers in the vertical direction, are held by coupling means
67, 68 and 69.
[0005] When voltage is applied from the electrodes, the respective
piezoelectric bodies 61 through 66 vibrate in the dual modes and
the combined vibration thereof is transmitted to the respective
output fetching members 71 through 76 to move an object abutting
with the output fetching members 71 through 76.
[0006] It is designed to obtain a high output by taking out the
output from the plurality of piezoelectric bodies 61 through
66.
[0007] However, because the respective piezoelectric bodies 61
through 66 are fixed merely by part thereof by the coupling means
67 through 69, the vibrating direction may vary among the
respective piezoelectric bodies 61 through 66 in the ultrasonic
motor described above. It also has had a technological problem that
because the vibration of the fixed parts of the piezoelectric
bodies 61 through 66 is suppressed, it causes vibration loss and
the output cannot be taken out effectively.
[0008] Still more, it is not preferable to use the above-mentioned
coupling means 67 through 69 as the separate members for fixing the
respective piezoelectric bodies 61 through 66 because it enlarges
and complicates the whole structure of the motor and because the
production process thereof is complicated by adding the step for
mounting the coupling means 67 through 69.
[0009] Meanwhile, although the above-mentioned problem may be
solved by laminating the piezoelectric bodies in a body in the
polarizing direction and by taking out the output only by the
piezoelectric transverse effect, there is a technological problem
that a high output cannot be obtained because the electric-mechanic
coupling coefficient of the piezoelectric transverse effect is
small.
SUMMARY OF THE INVENTION
[0010] Accordingly, it is an object of the present invention to
solve the above-mentioned technological problems by providing an
ultrasonic motor whose vibration loss is suppressed, whose
structure is miniaturized, whose production process is simplified
and which is capable of utilizing electrical energy
efficiently.
[0011] It is another object of the present invention to provide an
electronic apparatus equipped with an ultrasonic motor.
[0012] In order to achieve the above-mentioned objectives, an
inventive ultrasonic motor comprises, as described in claim 1, a
first piezoelectric body having a first polarized portion excited
when voltage is applied and a second piezoelectric body that is
laminated with the first piezoelectric body in the longitudinal
direction parallel to the polarizing direction and having a first
polarized portion at position separated from the first polarized
portion of the first piezoelectric body in the transverse direction
vertical to the polarizing direction and moves a moving body by
vibration into which stretching vibration and bending vibration
caused by vibrations of the first polarized portion of the first
piezoelectric body and the first polarized portion of the second
piezoelectric body in the longitudinal direction.
[0013] Thereby, the polarized portion of the first piezoelectric
body and the polarized portion of the second piezoelectric body
excite in the vertical and horizontal directions, respectively.
Then, the stretching vibration is produced when the respective
vibrations in the longitudinal direction overlap and the bending
vibration is produced from the implication between the transverse
vibrations and the stretching vibration therearound. The moving
body is then moved by elliptic vibration obtained by combining the
stretching vibration and the bending vibration.
[0014] Further, the piezoelectric vibrators are laminated in a body
without using fixing means, so that the vibration is not suppressed
and the vibrating direction is fixed.
[0015] Accordingly, the invention allows electrical energy to be
utilized very efficiently by utilizing the longitudinal vibration
caused by the piezoelectric longitudinal effect whose
electrical-mechanical coupling coefficient is large, vibration loss
to be suppressed, the vibrating direction to be prevented from
varying, the structure of the device to be miniaturized and the
production process to be simplified.
[0016] The invention described in claim 2 is characterized in that
the first and second piezoelectric bodies have second polarized
portions further at positions corresponding to the first polarized
portions of own in the invention described in claim 1.
[0017] Thereby, elliptic vibration for rotating in the reverse
direction may be taken out by exciting only the second polarized
portions of the respective piezoelectric bodies to produce bending
vibration having a different phase for example. Or, the bending
vibration may be amplified by exciting the second polarized portion
with a different phase from the first polarized portion in the same
time. Accordingly, driving force in the both normal and reverse
directions may be obtained and the output may be controlled by
displacing the bending vibration or by changing the phase.
[0018] The invention described in claim 3 is characterized in that
a third piezoelectric body which vibrates in the same phase with
the stretching vibration is laminated in a body in the ultrasonic
motor-described in claim 1.
[0019] Thereby, the third piezoelectric body vibrates in the
longitudinal direction in the same phase with the stretching
vibration and amplifies the stretching vibration. Accordingly, the
high-output ultrasonic motor may be realized.
[0020] The invention described in claim 4 is characterized in that
a third polarized portion that vibrates in the same phase with the
stretching vibration is provided between the first polarized
portion of the first piezoelectric body and the first polarized
portion of the second piezoelectric body at least in either one of
the first piezoelectric body and the second piezoelectric body.
Thereby, the third polarized portion vibrates in the longitudinal
direction in the same phase with the stretching vibration and
amplifies the stretching vibration. Accordingly, the high-output
ultrasonic motor may be realized.
[0021] Here, the third polarized portion may be provided only in
the first piezoelectric body, only in the second piezoelectric body
or in the first and second piezoelectric bodies.
[0022] The invention described in claim 5 is characterized in that
the moving body is abutted to the laminated piezoelectric vibrator
in the horizontal direction in the ultrasonic motor described in
claim 1.
[0023] Thereby, the laminated piezoelectric vibrator moves the
moving body by the vibration combined in the horizontal
direction.
[0024] The invention described in claim 6 is characterized in that
the laminated piezoelectric vibrator is abutted at least one point
of a spherical moving body in the ultrasonic motor described in any
one of claims 1 through 4.
[0025] Thereby, the spherical moving body may be moved about an
arbitrary axis by applying driving force to one point of the
spherical moving body by the laminated piezoelectric vibrator or
may be moved arbitrary by applying driving force to a plurality of
points.
[0026] The invention described in claim 7 is characterized in that
an electronic apparatus equipped with the ultrasonic motor
comprises the ultrasonic motor described in any one of claims 1
through 6. Thereby, the electronic apparatus equipped with the
ultrasonic motor having the ultrasonic motor as a driving source
may be realized.
[0027] The specific nature of the invention, as well as other
objects, uses and advantages thereof, will clearly appear from the
following description and from the accompanying drawings in which
like numerals refer to like parts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIGS. 1a and 1b are explanatory drawings showing a first
embodiment in which the present invention is applied to an
ultrasonic motor, wherein
[0029] FIG. 1a shows a sectional structure thereof and
[0030] FIG. 1b shows a planar structure thereof;
[0031] FIGS. 2a through 2d are explanatory diagrams, wherein
[0032] FIGS. 2a and 2c show the planar structure of the
piezoelectric vibrator shown in FIG. 1 and
[0033] FIGS. 2b and 2d show the structure of the piezoelectric
body;
[0034] FIGS. 3a and 3b are explanatory diagrams, wherein
[0035] FIG. 3a shows a structure of one side electrode shown in
FIG. 1 and
[0036] FIG. 3b shows a structure of another side electrode shown in
FIG. 1;
[0037] FIG. 4 is an explanatory diagram showing a vibrating state
of the vibrator shown in FIG. 1;
[0038] FIGS. 5a through 5f show a second embodiment in which the
present invention is applied to an ultrasonic motor, wherein
[0039] FIGS. 5a, 5c and 5e show a planar structure of the
piezoelectric vibrator and
[0040] FIGS. 5b, 5d and 5f show a planar structure of the
piezoelectric body;
[0041] FIGS. 6a and 6b are explanatory diagrams, wherein
[0042] FIG. 6a shows disposition of one side electrode shown in
FIG. 5 and
[0043] FIG. 6b shows disposition of another side electrode;
[0044] FIGS. 7a through 7d are explanatory drawings showing a third
embodiment in which the present invention is applied to an
ultrasonic motor, wherein
[0045] FIGS. 7a and 7c shows a planar structure of the
piezoelectric vibrator and
[0046] FIGS. 7b and 7d show a planar structure of the piezoelectric
body;
[0047] FIGS. 8a and 8b are explanatory diagrams, wherein
[0048] FIG. 8a shows disposition of one side electrode shown in
FIG. 7 and
[0049] FIG. 8b shows disposition of another side electrode;
[0050] FIGS. 9a through 9d are explanatory drawings showing a
fourth embodiment in which the present invention is applied to an
ultrasonic motor, wherein
[0051] FIGS. 9a and 9c shows a planar structure of the
piezoelectric vibrator and
[0052] FIGS. 9b and 9d show a planar structure of the piezoelectric
body;
[0053] FIGS. 10a and 10b are explanatory diagrams, wherein
[0054] FIG. 10a shows disposition of one side electrode shown in
FIG. 9 and
[0055] FIG. 10b shows disposition of another side electrode;
[0056] FIGS. 11a through 11d are explanatory drawings showing a
fifth embodiment in which the present invention is applied to an
ultrasonic motor, wherein FIGS. 1a and 1c shows a planar structure
of the piezoelectric vibrator and FIGS. 11b and 11d show a planar
structure of the piezoelectric body;
[0057] FIGS. 12a and 12b are explanatory diagrams, wherein
[0058] FIG. 12a shows disposition of one side electrode shown in
FIG. 11 and
[0059] FIG. 12b shows disposition of another side electrode;
[0060] FIG. 13 is an explanatory diagram showing a side structure
of a sixth embodiment in which the present invention is applied to
an ultrasonic motor;
[0061] FIG. 14 is an explanatory diagram showing a structure of a
seventh embodiment in which the present invention is applied to an
ultrasonic motor;
[0062] FIG. 15 is an explanatory diagram showing a block of an
eighth embodiment in which the present invention is applied to an
ultrasonic motor; and
[0063] FIG. 16 is a perspective view showing a structure of a prior
art ultrasonic motor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0064] Preferred embodiments to which the present invention has
been applied will be explained below in detail with reference to
FIGS. 1 through 15.
[0065] [First Embodiment]
[0066] FIGS. 1a and 1b are explanatory drawings showing a first
embodiment in which the present invention is applied to an
ultrasonic motor, wherein FIG. 1a shows a sectional structure
thereof and FIG. 1b shows a planar structure thereof.
[0067] As shown in FIGS. 1a and 1b, according to the present
embodiment, the ultrasonic motor comprises a vibrating body 10, an
output fetching member 31 provided on an end of the vibrating body
10 in the laminating direction, a moving body 50 abutting with the
output fetching member 31 and pressurizing mechanisms 41 and 42 for
supporting the vibrating body 10 and pressurizing the moving body
50 and the output fetching member 31.
[0068] The moving body 50 comprises a rotor 51 having a rotary
bearing, a rotary shaft 52 penetrating through the rotor 51 and a
fixing member 53 for fixing the basal end of the rotary shaft
52.
[0069] The output fetching member 31 is a rectangular
parallelepiped member having a rigidity. It is provided to transmit
vibration of the vibrating body 10 to the rotor 51 and to amplify
displacement of the vibration.
[0070] The pressurizing mechanisms 41 and 42 comprise a fixing
member 42 provided so as to face to the vibrating body 10 and a
pressurizing member 41 for pressurizing the vibrating body 10
toward the moving body 50.
[0071] The vibrating body 10 is constructed by alternately
laminating piezoelectric bodies 11A, 11B, 11C, 11D and 11E and
piezoelectric bodies 12A, 12B, 12C, 12D and 12E in a body such that
the piezoelectric body 11A and piezoelectric body 12A are paired
and the piezoelectric body 11B and 12B are paired for example.
[0072] Planar electrodes 21 are fixed on one end face of the
respective piezoelectric bodies 11A through 11E at region
corresponding to polarization and reference electrodes 22 are fixed
on the face of the respective piezoelectric bodies 12A through 12E
facing to the planar electrodes 21 of the piezoelectric bodies 11A
through 11E as counter electrodes.
[0073] FIGS. 2a through 2d show the planar structure of the
piezoelectric bodies 11A through 11E and the piezoelectric bodies
12A through 12E and patterns of the electrodes 21 and 22.
[0074] It is noted that the piezoelectric body 11A as a first
piezoelectric body of the invention is identical with the
piezoelectric bodies 11B and 11C and the piezoelectric body 11D as
a second piezoelectric body of the invention is identical with the
piezoelectric body 11E and the piezoelectric body 12A is also
identical with the piezoelectric bodies 12B through 12E, so that
only the piezoelectric bodies 11A and 11D and the piezoelectric
bodies 12A and 12D which are paired with them will be explained
below as the representative piezoelectric bodies.
[0075] As shown in FIGS. 2a through 2d, the piezoelectric bodies
11A and 11D and the piezoelectric bodies 12A and 12D are
rectangular plate-like members for which a ferroelectric material
such as barium titanate and lead zirconate titanate is used. The
aspect ratio of the vibrating body 10 is set so as to cause a
predetermined resonance frequency.
[0076] As shown in FIGS. 2a and 2c, long sides of the rectangular
plane of the piezoelectric bodies 11A and 11D are bisected so as to
divide the plane into two parts 11a and 11b and 11c and 11d and
planar electrodes 21a and 21b and 21c and 21d are fixed in
correspondence to the respective polarized portions 11a through
11d.
[0077] Part of the one planar electrode 21a fixed to the
piezoelectric body 11A is connected with a side electrode described
later at one long edge of the rectangular plane of the
piezoelectric body 11A and part of the other planar electrode 21b
is connected with the side electrode at the other long edge of the
rectangular plane. Further, part of the planar electrode 21d fixed
to the piezoelectric body 11D is connected with the side electrode
at one long edge of the rectangular plane and part of the planar
electrode 21c is connected thereto at the other long edge of the
rectangular plane.
[0078] Reference electrodes 22a and 22b are fixed almost on the
whole surface of the rectangular plane of the piezoelectric bodies
12A and 12D as the reference for the planar electrodes 21a and 21b
and 21c and 21d as shown in FIG. 2b. Part of the reference
electrodes 22a and 22b is connected with the side electrode at the
other long edge of the rectangular plane.
[0079] A polarization process is implemented on the vibrating body
10 laminated in a body by applying a voltage exceeding a resistive
electric field based on the electrodes 22 and by setting the
electrodes 21 as plus as shown in the figures.
[0080] FIGS. 3a and 3b show patterns of the side electrodes 32, 33,
34, 35 and 36 provided along the plane of lamination of the
vibrating body 10.
[0081] The side electrodes 32 through 34 are provided on one side
face corresponding to the long edge of the vibrating body 10 as
shown in FIG. 3a and the side electrodes 35 and 36 are provided on
the other side face as shown in FIG. 3b.
[0082] Here, the side electrode 32 is connected to the planar
electrodes 21b of the piezoelectric bodies 11A through 11C, the
side electrode 33 is connected to the reference electrodes 22a and
22b of the piezoelectric bodies 12A through 12E and the side
electrode 34 is connected to the planar electrodes 21c of the
piezoelectric bodies 11D and 11E. Meanwhle, the side electrode 35
is connected to the planar electrodes 21a of the piezoelectric
bodies 11A through 11C and the side electrode 36 is connected to
the planar electrodes 21d of the piezoelectric bodies 11D and
11E.
[0083] Next, a first use of the ultrasonic motor will be explained
based on FIGS. 2 through 4.
[0084] When voltage is applied to the respective side electrodes
32, 33 and 34 shown in FIG. 3a to normally rotate the rotor 51 at
first, voltage having the same phase is applied to the planar
electrodes 21b of the piezoelectric bodies 11A through 11C, the
reference electrodes 22a and 22b of the piezoelectric bodies 12A
through 12E and the planar electrodes 21c of the piezoelectric
bodies 11D and 11E as shown in FIG. 2.
[0085] The polarized portions 11b of the piezoelectric bodies 11A
through 11C and the polarized portions 11c of the piezoelectric
bodies 11D and 11E as first polarized portions to which the voltage
is applied stretch respectively in the direction parallel to the
direction in which the voltage is applied (hereinafter referred to
as a piezoelectric longitudinal effect).
[0086] FIG. 4 shows a vibrating state of the vibrating body 10.
[0087] When the polarized portions 11b of the piezoelectric bodies
11A through 11C and the polarized portions 11c of the piezoelectric
bodies 11D and 11E stretch in the longitudinal direction due to the
piezoelectric longitudinal effect, the vibrating body 10 causes
bending vibration A as well as stretching vibration B as a whole as
shown in the figure.
[0088] Here, an electric-mechanical coupling coefficient of the
piezoelectric longitudinal effect is greater than that of the
piezoelectric transverse effect, an overall energy efficiency is
enhanced by utilizing the piezoelectric longitudinal effect.
[0089] Further, the vibration of each vibrator is not suppressed
and the vibrating direction is also fixed by laminating the
piezoelectric vibrators 11A through 11E in a body without using any
fixing means.
[0090] Then, the output fetching member 31 transmits and amplifies
elliptic vibration C obtained by combining the bending vibration A
and the stretching vibration B.
[0091] The rotor 51 abutting with the output fetching member 31
rotates in the normal direction by periodically receiving
frictional force of the fixed direction.
[0092] Meanwhile, the rotor 51 may be rotated in the opposite
direction as follows. When voltage is applied to the respective
side electrodes 33, 35 and 36 shown in FIG. 3, voltage having the
same phase is applied to the planar electrodes 21a of the
piezoelectric bodies 11A through 11A, the reference electrodes 22a
and 22b of the piezoelectric bodies 12A through 12E and the planar
electrodes 21d of the piezoelectric bodies 11D and 11E as shown in
FIG. 2.
[0093] At this time, the polarized portions 11a and the polarized
portions 11d as second polarized portions of the present invention
are excited and the vibrating body 10 causes the stretching
vibration B and bending vibration whose phase differs by
180.degree. from the above-mentioned bending vibration A.
[0094] Then, elliptic vibration in the opposite direction from the
elliptic vibration C is produced at the edge of the output fetching
member 31 and the rotor 51 receives frictional force in the
opposite direction, thus rotating in the opposite direction.
[0095] A second use of the ultrasonic motor will be explained
further.
[0096] That is, voltage having the same phase is applied to the
side electrodes 32 and 34 shown in FIG. 3 and voltage having the
same phase and different from that applied to the side electrodes
32 and 34 is applied to the side electrodes 35 and 36.
[0097] At this time, when the polarized portions 21b of the
piezoelectric bodies 11A through 11C and the polarized portions 11c
of the piezoelectric bodies 11D and 11E contract in the
longitudinal direction for example, it corresponds to that the
polarized portions 11a of the piezoelectric bodies 11A through 11C
and the polarized portions 11d of the piezoelectric bodies 11D and
11E stretch in the longitudinal direction.
[0098] Thereafter, the bending vibration and the stretching
vibration are combined and the output fetching member 31 causes
modified elliptic vibration.
[0099] It is noted that the phase difference of the voltages
applied to the side electrodes 32 and 34 and the side electrodes 35
and 36 may be appropriately changed.
[0100] Thereby, according to the present embodiment, the polarized
portions 21a through 21d of the respective piezoelectric bodies 11A
through 11E are excited respectively in the longitudinal direction
and the stretching vibration is produced by overlapping the
respective vibrations in the longitudinal direction, so that
electrical energy may be utilized very efficiently by utilizing the
large exciting force.
[0101] Further, because the vibration is not suppressed and the
vibrating direction is fixed by laminating the piezoelectric bodies
11A through 11E in a body without using any fixing means, vibration
loss of the respective piezoelectric bodies 11A through 11E may be
suppressed, the vibrating direction may be prevented from varying
and the structure of the device may be simplified.
[0102] Further, the driving force in the both normal and reverse
directions may be obtained just by changing the phase of the
voltage for exciting the polarized portions 11b and 11c and the
polarized portions 11a and 11d.
[0103] [Second Embodiment]
[0104] FIGS. 5 and 6 show a second embodiment in which the present
invention is applied to an ultrasonic motor, wherein FIGS. 5a
through 5f show a basic laminating structure of the vibrating body
10 and FIGS. 6a and 6b show disposition of side electrodes.
[0105] As shown in FIGS. 5a, 5b, 5e and 5f, the piezoelectric
bodies 11A and 11B and the piezoelectric bodies 12A and 12C which
are paired with them are constructed almost in the same manner with
the first embodiment, so that their explanation will be omitted
here.
[0106] The present embodiment is characterized in that a
piezoelectric body 13A, i.e., a third piezoelectric body, in which
a planar electrode 23a is fixed almost on the whole surface of the
rectangular plane thereof and a piezoelectric body 12B that is
paired with the piezoelectric body 13A are inserted between the
pair of piezoelectric bodies 11A and 11B as shown in FIGS. 5c and
5d. A polarization process is implemented on the piezoelectric body
13A in correspondence to the planar electrode 23a and a reference
electrode 22b is fixed to the piezoelectric body 12B as a counter
electrode.
[0107] As shown in FIG. 6a, the side electrode 32 is connected to
the planar electrode 21b on the front right side of the
piezoelectric body 11A, the side electrode 33 is connected to the
reference electrodes 22a, 22b and 22c of the piezoelectric bodies
12A, 12B and 12C and the side electrode 34 is connected to the
planar electrode 21c on the front left side of the piezoelectric
body 11B.
[0108] Further, as shown in FIG. 6b, the side electrode 35 is
connected to the planar electrode 11a on the front left side of the
piezoelectric body 11A, the side electrode 36 is connected to the
planar electrode 21d on the front right side of the piezoelectric
body 11B and the side electrode 37 is connected to the planar
electrode 23a of the piezoelectric body 13A.
[0109] Next, a first use of the present embodiment will be
explained based on FIGS. 5 and 6.
[0110] When voltage is applied to the side electrodes 32, 33, 34
and 37 shown in FIG. 6 to normally rotate the rotor 51 at first,
voltage having the same phase is applied to the planar electrodes
21b on the front right side of the piezoelectric body 11A, the
reference electrodes 22a, 22b and 22c of the piezoelectric bodies
12A through 12C, the planar electrode 21c on the front left side of
the piezoelectric body 11B and the planar electrode 23a of the
piezoelectric body 13A as shown in FIG. 5.
[0111] At this time, the vibrating body 10 causes stretching
vibration and bending vibration when the polarized portion 11b on
the front right side of the piezoelectric body 11A and the
polarized portion 11c on the front left side of the piezoelectric
body 11B, i.e., the first polarized portions, are excited.
[0112] The piezoelectric body 13A also causes stretching vibration
in the same phase, thus amplifying the stretching vibration of the
vibrating body 10.
[0113] Then, the output fetching member 31 causes elliptic
vibration and the rotor 51 rotates normally by receiving the
frictional force.
[0114] The rotor 51 may be rotated in the opposite direction as
follows. When voltage is applied to the side electrodes 33, 35, 36
and 37 shown in FIG. 6, voltage having the same phase is applied to
the planar electrode 21a on the front left side of the
piezoelectric body 11A, the reference electrodes 22a through 22c of
the piezoelectric bodies 12A through 12C, the planar electrode 21d
on the front right side of the piezoelectric body 11B and the
planar electrode 23a of the piezoelectric body 13A, respectively,
as shown in FIG. 5.
[0115] The polarized portion 11a on the front left side of the
piezoelectric body 11A, the polarized portion 21d on the front
right side of the piezoelectric body 11B and almost the whole plane
of the piezoelectric body 13A, i.e., the second polarized portions,
are excited and the vibrating body 10 causes stretching vibration
and bending vibration. Then, the output fetching member 31 causes
elliptic vibration in the opposite direction and rotates the rotor
51 in the opposite direction.
[0116] Meanwhile, in a second use of the ultrasonic motor of the
present embodiment, at least two groups among three groups of the
side electrodes 32 and 34, the side electrodes 35 and 36 and the
side electrode 37 are selected and voltages having different phases
are applied to the respective groups.
[0117] When the two groups of the side electrodes 32 and 34 and the
side electrode 37 are selected for example, the output fetching
member 31 causes elliptic vibration having a mode different from
the elliptic vibration in the first use.
[0118] It is also possible to apply different voltages to the
respective groups to variegate the elliptic vibration drawn by the
output fetching member 31.
[0119] As described above, according to the present embodiment, the
high-output ultrasonic motor may be realized because the stretching
vibration is amplified by the piezoelectric body 13A.
[0120] [Third Embodiment]
[0121] FIGS. 7 and 8 show a third embodiment in which the present
invention is applied to an ultrasonic motor, wherein FIGS. 7a
through 7d show a basic laminating structure and FIGS. 8a and 8b
show disposition of side electrodes.
[0122] As shown in FIGS. 7b and 7d, the piezoelectric bodies 12A
and 12B which are paired with piezoelectric bodies 14A and 14B are
constructed almost in the same manner with the first embodiment, so
that their explanation will be omitted here.
[0123] The present embodiment is characterized in that rectangular
planes of the piezoelectric bodies 14A and 14B as first and second
piezoelectric vibrators are divided into three parts and planar
electrodes 24a through 24c and 24d through 24f are fixed
corresponding to the respective divided planes 14a through 14c and
14d through 14f as shown in FIGS. 7a and 7c. Then, a polarization
process is implemented on the respective divided planes 14a through
14c and 14d through 14 by setting the front page side thereof as
plus and the back side thereof as minus and by applying a voltage
exceeding a resistive electric field to the planar electrodes 21a
through 21d.
[0124] Part of one planar electrode 24a fixed to the piezoelectric
vibrator 14A is connected at one long edge of the rectangular plane
of the piezoelectric body 14A and part of the planar electrodes 24b
and 24c is connected at the other long edge of the rectangular
plane. Further, part of the planar electrode 24e fixed to the
piezoelectric body 14B is connected at one long edge of the
rectangular plane and part of the planar electrodes 24d and 24f is
connected at the other long edge of the rectangular plane.
[0125] The side electrode 32 shown in FIG. 8a is connected to the
planar electrode 24b on the front right side of the piezoelectric
body 14A, the side electrode 34 is connected to the planar
electrode 24d on the front left side of the piezoelectric body 14B
and the side electrode 37 is connected to the planar electrodes 24c
and 24f at the front center of the planar electrodes 14A and
14B.
[0126] Further, the side electrode 35 shown in FIG. 8b is connected
to the planar electrode 24a on the front left side of the
piezoelectric body 14A, the side electrode 36 is connected to the
planar electrode 24e on the front right side of the piezoelectric
body 14B and the side electrode 33 is connected to the reference
electrodes 22a and 22b of the piezoelectric bodies 12A and 12B.
[0127] Next, a first use of the present embodiment will be
explained based on FIGS. 7 and 8.
[0128] When voltage is applied to the side electrodes 32, 34 and 37
based on the side electrode 33 as shown in FIG. 8 to normally
rotate the rotor 51 at first, voltage having the same phase is
applied to the planar electrode 24b on the front right side of the
piezoelectric body 14A, the planar electrode 24c at the center
thereof, the planar electrode 24d on the front left side of the
piezoelectric body 14B, the planar electrode 24f at the center
thereof and the reference electrodes 22a and 22b of the
piezoelectric bodies 12A and 12B as shown in FIG. 7.
[0129] At this time, the vibrating body 10 causes stretching
vibration and bending vibration when the polarized portion 14b on
the front right side of the piezoelectric body 14A and the
polarized portion 14d on the front left side of the piezoelectric
body 14B as the first polarized portions are excited.
[0130] The polarized portion 14c at the center of the piezoelectric
body 14A and the polarized portion 14f at the center of the
piezoelectric body 14B as third polarized portions causes
stretching vibration in the longitudinal direction, thus amplifying
the stretching vibration of the vibrating body 10.
[0131] Then, the output fetching member 31 causes elliptic
vibration and the rotor 51 rotates normally by receiving the
frictional force.
[0132] The rotor 51 may be rotated in the opposite direction as
follows. That is, when a voltage is applied to the side electrodes
35, 36 and 37 based on the side electrode 33 shown in FIG. 8,
voltage having the same phase is applied to the planar electrode
24a on the front left side of the piezoelectric body 14A, the
planar electrode 24c at the center thereof, the planar electrode
24e on the front right side of the piezoelectric body 14B, the
planar electrode 24f at the center thereof and the reference
electrodes 22a and 22b of the piezoelectric bodies 12A and 12B as
shown in FIG. 7.
[0133] The polarized portion 14a on the front left side of the
piezoelectric body 14A as the second polarized portion, the
polarized portion 14c at the center as the third polarized portion,
the polarized portion 24e on the front right side of the
piezoelectric body 14B and the polarized portion 24f at the center
as the third polarized portion are excited and the vibrating body
10 causes stretching vibration and bending vibration. Then, the
output fetching member 31 causes elliptic vibration in the opposite
direction and rotates the rotor 51 in the opposite direction.
[0134] Meanwhile, as a second use of the ultrasonic motor of the
present embodiment, at least two groups among three groups of the
side electrodes 32 and 34, the side electrodes 35 and 36 and the
side electrode 37 are selected and voltages having different phases
are applied to the respective groups.
[0135] When the two groups of the side electrodes 32 and 34 and the
side electrode 37 are selected for example, the output fetching
member 31 causes different elliptic vibration from the elliptic
vibration in the first use.
[0136] It is also possible to apply different voltages to the
respective groups to variegate the elliptic vibration drawn by the
output fetching member 31.
[0137] As described above, according to the present embodiment, the
high-output ultrasonic motor may be obtained because the polarized
portion 14c at the center of the piezoelectric body 14A and the
polarized portion 14f at the center of the piezoelectric body 14B
are provided to amplify the stretching vibration in the
longitudinal direction.
[0138] [Fourth Embodiment]
[0139] FIGS. 9 and 10 show a fourth embodiment in which the present
invention is applied to an ultrasonic motor, wherein FIGS. 9a
through 9d show a basic laminating structure and FIGS. 10a and 10b
show disposition of side electrodes.
[0140] As shown in FIGS. 9b and 9d, the piezoelectric bodies 12A
and 12B which are paired with piezoelectric bodies 15A and 15B are
constructed almost in the same manner with the first embodiment, so
that their explanation will be omitted here.
[0141] The present embodiment is characterized in that rectangular
planes of the piezoelectric bodies 15A and 15B are divided into
three parts and planar electrodes 25a, 25b, 25c, 25d, 25e and 25f
are fixed corresponding to the respective divided planes 15a
through 15c and 15d through 15f as shown in FIGS. 9a and 9c. Then,
a polarization process is implemented on the planar electrodes 25b
and 25c of the piezoelectric body 15A and the planar electrodes 25d
and 25f of the piezoelectric body 15B by setting the front page
side thereof as plus and the back side thereof as minus and on the
planar electrode 25a of the piezoelectric body 15A and the planar
electrode 25e of the piezoelectric body 15B by setting the front
page side thereof as minus and the back side thereof as plus.
[0142] Part of one planar electrode 25a fixed to the planar
electrode 15A is connected at one long edge of the rectangular
plane of the piezoelectric body 15A and part of the planar
electrodes 25b and 25c is connected at the other long edge of the
rectangular plane. Further, part of the planar electrode 25e fixed
to the piezoelectric body 15B is connected at one long edge of the
rectangular plane and part of the planar electrodes 25d and 25f is
connected at the other long edge of the rectangular plane.
[0143] The side electrode 32 shown in FIG. 10a is connected to the
planar electrode 25b on the front right side of the planar
electrode 15A, the side electrode 34 is connected to the planar
electrode 25d on the front left side of the piezoelectric body 15B
and the side electrode 37 is connected to the planar electrodes 25c
and 25f at the front center of the piezoelectric bodies 15A and
15B.
[0144] Further, the side electrode 35 shown in FIG. 10b is
connected to the planar electrode 25a on the front left side of the
piezoelectric body 15A, the side electrode 36 is connected to the
planar electrode 25e on the front right side of the piezoelectric
body 15B and the side electrode 33 is connected to the reference
electrodes 22a and 22b of the piezoelectric bodies 12A and 12B.
[0145] Next, a first use of the present embodiment will be
explained based on FIGS. 9 and 10.
[0146] When voltage is applied to all of the side electrodes 32,
34, 35, 36 and 37 based on the side electrode 33 shown in FIG. 10
to normally rotate the rotor 51 at first, voltage having the same
phase is applied to the planar electrodes 25a through 25c of the
piezoelectric body 15A, the planar electrodes 25d through 25f of
the piezoelectric body 15B and the reference electrodes 22a and 22b
of the piezoelectric bodies 12A and 12B as shown in FIG. 9.
[0147] At this time, when the polarized portion 15b on the front
right side of the piezoelectric body 15A and the polarized portion
15d on the front left side of the piezoelectric body 15B as the
first polarized portions are stretched in the longitudinal
direction, the polarized portion 15a on the front left side of the
piezoelectric body 15A and the polarized portion 15d on the front
right side of the piezoelectric body 15B as second polarized
portions contract in the longitudinal direction, thus amplifying
the bending vibration of the vibrating body 10.
[0148] The polarized portion 15c at the center of the piezoelectric
body 15A and the polarized portion 15f at the center of the
piezoelectric body 15B as third polarized portions causes
stretching vibration in the same phase in the longitudinal
direction, thus amplifying the stretching vibration of the
vibrating body 10.
[0149] Then, the output fetching member 31 causes amplified
elliptic vibration and the rotor 51 rotates normally at high speed
by receiving the greater frictional force.
[0150] As described above, according to the present embodiment, the
rotor 51 rotates at higher speed and the high-output ultrasonic
motor may be obtained because the polarization process of the
piezoelectric bodies 15A and 15B is arranged so as to amplify both
of the stretching vibration and bending vibration of the vibrating
body 10 and so that the output fetching member 31 causes amplified
elliptic vibration.
[0151] [Fifth Embodiment]
[0152] FIGS. 11 and 12 show a fifth embodiment in which the present
invention is applied to an ultrasonic motor, wherein FIGS. 11a
through 11f show a basic laminating structure and FIGS. 12a and 12b
show disposition of side electrodes.
[0153] As shown in FIGS. 11b, 11c, 11d and 11f, the present
embodiment are constructed almost in the same manner with the
second embodiment, so that the explanation on the piezoelectric
body 13A, piezoelectric bodies 12A, 12B and 12C will be omitted
here.
[0154] The present embodiment is characterized in that a long side
of rectangular planes of the piezoelectric bodies 16A and 16B as
the first and second piezoelectric bodies are bisected and planar
electrodes 26a, 26b, 26c and 26d are fixed corresponding to the
respective bisected planes 16a, 16b, 16c and 16d as shown in FIGS.
11a and 11c. Then, a polarization process is implemented on the
planar electrode 26b of the piezoelectric body 16A and the planar
electrode 26c of the piezoelectric body 16B by setting the front
page side thereof as plus and the back side thereof as minus and on
the planar electrode 26a of the piezoelectric body 16A and the
planar electrode 26d of the piezoelectric body 16B by setting the
front page side thereof as minus and the back side thereof as
plus.
[0155] Part of one planar electrode 26a fixed to the piezoelectric
body 16A is connected with the side electrode described later at
one long edge of the rectangular plane of the piezoelectric body
16A and part of the other planar electrode 26b is connected with
the side electrode at the other long edge of the rectangular plane.
Further, part of the planar electrode 26d fixed to the
piezoelectric body 16B is connected at one long edge of the
rectangular plane and part of the planar electrode 26c is connected
at the other long edge of the rectangular plane.
[0156] As shown in FIG. 12a, the side electrode 32 is connected to
the planar electrode 26b on the front right side of the planar
electrode 16A, the side electrode 33 is connected to the reference
electrodes 22a, 22b and 22c of the piezoelectric bodies 12A, 12B
and 12C, the side electrode 34 is connected to the planar electrode
26c on the front left side of the piezoelectric body 16B.
[0157] Further, as shown in FIG. 6b, the side electrode 35 is
connected to the planar electrode 26a on the front left side of the
piezoelectric body 16A, the side electrode 36 is connected to the
planar electrode 26d on the front right side of the piezoelectric
body 16B and the side electrode 37 is connected to the planar
electrode 23a of the piezoelectric body 13A.
[0158] Next, the use of the present embodiment will be explained
based on FIGS. 11 and 12.
[0159] When voltage is applied to all of the side electrodes 32,
33, 34, 35, 36 and 37 as shown in FIG. 12 to normally rotate the
rotor 51 at first, voltage having the same phase is applied to the
planar electrodes 26a and 26b of the piezoelectric body 16A, the
planar electrodes 26c and 26d of the piezoelectric body 16B, the
planar electrode 23a of the piezoelectric body 13A and the
reference electrodes 22a, 22b and 22c of the piezoelectric bodies
12A, 12B and 12C as shown in FIG. 11.
[0160] At this time, when the polarized portion 16b on the front
right side of the piezoelectric body 16A and the polarized portion
16c on the front left side of the piezoelectric body 16B as the
first polarized portions are stretched in the longitudinal
direction, the polarized portion 16a on the front left side of the
piezoelectric body 16A and the polarized portion 16d on the front
right side of the piezoelectric body 16B as second polarized
portions contract in the longitudinal direction, thus amplifying
the bending vibration of the vibrating body 10.
[0161] The piezoelectric body 13A as the third piezoelectric body
causes stretching vibration in the same phase in the longitudinal
direction; thus amplifying the stretching vibration of the
vibrating body 10.
[0162] Then, the output fetching member 31 causes amplified
elliptic vibration and the rotor 51 rotates normally at higher
speed by receiving the greater frictional force.
[0163] As described above, according to the present embodiment, the
rotor 51 rotates at higher speed and a high output may be obtained
because the present embodiment is arranged so that the bending
vibration is amplified by the polarized portion 16a on the front
left side of the piezoelectric body 16A and the polarized portion
16d on the front right side of the piezoelectric body 16B and the
stretching vibration of the vibrating body 10 is amplified by the
piezoelectric body 13A and the stretching vibration and the bending
vibration of the vibrating body 10 are both amplified.
[0164] [Sixth Embodiment]
[0165] FIG. 13 shows a side structure of a sixth embodiment in
which the present invention is applied to an ultrasonic motor.
[0166] While the present embodiment is constructed almost in the
same manner with the first embodiment, it is characterized in that
the vibrating body 10 is fixed, a pair of output fetching members
38 and 39 are fixed at the edge portion thereof in the direction
vertical to the laminating direction and the output fetching
members 38 and 39 are abutted with a moving body 54.
[0167] Thereby, elliptic vibration obtained by combining bending
vibration and stretching vibration is produced even in the
horizontal direction of the vibrating body 10, so that the moving
body 54 abutting with the output fetching members 38 and 39 can
move linearly in the right or left direction by using the
piezoelectric vibrators as described above.
[0168] [Seventh Embodiment]
[0169] FIG. 14 shows a structure of a seventh embodiment in which
the present invention is applied to an ultrasonic motor.
[0170] The present embodiment is characterized in that two
vibrating bodies 10A and 10B are disposed while opening by
90.degree. with respect to a spherical rotor 55 centering on a
point Z in the figure and respective output fetching members 31A
and 31B abut with the spherical rotor 55.
[0171] Here, the vibrating bodies 10A and 10B have the same
laminating structure and disposition of electrodes with the second
embodiment and only the stretching vibration, only the bending
vibration or the combined elliptic vibration may be produced by
selecting the electrodes to which voltage is applied.
[0172] The use of the present embodiment will be explained below
based on FIG. 14.
[0173] The spherical rotor 55 may be moved in triaxial directions
by vibrating the both vibrating bodies 10A and 10B. At this time,
the output fetching members 31A and 31B cause elliptic vibration,
respectively. The output fetching member 31A applies frictional
force in the direction of rotation about the Z-axis of the
spherical rotor 55 and the output fetching member 31B applies
frictional force in the direction of rotation about the X-axis of
the spherical rotor 55. The spherical rotor 55 rotates about the x
and Z-axes in the same time, thus realizing the triaxial
movement.
[0174] Meanwhile, the spherical rotor 55 may be rotated in one
direction by causing the vibrating body 10A to produce combined
vibration and the vibrating body 10B to produce only stretching
vibration.
[0175] At this time, the output fetching member 31A applies
frictional force to the spherical rotor 55 in the direction of
rotation about the Z-axis and the output fetching member 31B
stretches and applies force only in the direction of the center of
the spherical rotor 55, so that they do not hamper the spherical
rotor 55 from rotating centering on the Z-axis.
[0176] As described above, according to the present embodiment, the
use of the two vibrating bodies 10A and 10B allows the rotational
movement in one direction and the triaxial movement of the
spherical rotor 55 to be realized.
[0177] [Eighth Embodiment]
[0178] FIG. 15 is a block diagram showing an eighth embodiment in
which the inventive-ultrasonic motor is applied to an electronic
apparatus.
[0179] The electronic apparatus is realized by comprising the
above-mentioned vibrating body 10, a moving body 61 moved by the
vibrating body 10, a pressurizing mechanism 62 for applying
pressurizing force to the moving body 61 and the vibrating body 10,
a transmission mechanism 63 operating in linkage with the moving
body 61 and an output mechanism 64 that moves based on the
operation of the transmission mechanism 63.
[0180] Here, a transmission wheel such as a gear and a frictional
gear is used as the transmission mechanism 63. As the output
mechanism 64, a shutter driving mechanism and a lens driving
mechanism are used in cause of a camera for example, a needle
driving mechanism and a calendar driving mechanism are used in case
of an electronic watch and a cutter feeding mechanism and a
workpiece feeding mechanism are used in case of a work machine.
[0181] The electronic apparatus equipped with the ultrasonic motor
of the present embodiment may be realized in electronic watches,
measuring instruments, cameras, printers, work machines, robots,
moving apparatuses and the like.
[0182] Further, a driving mechanism may be realized just by the
ultrasonic motor itself by attaching an output shaft to the moving
body 61 and by comprising a power transmission mechanism for
transmitting torque from the output shaft.
[0183] As described above, according to the invention as described
in claim 1, the inventive ultrasonic motor is arranged such that
the polarized portion of the first piezoelectric body and the
polarized portion of the second piezoelectric body stretch
respectively in the polarizing direction so that stretching
vibration and bending vibration are produced by overlapping the
respective vibrations in the longitudinal direction, the output may
be increased by utilizing the vibration in the longitudinal
direction caused by the piezoelectric longitudinal effect and
electrical energy may be utilized very efficiently.
[0184] Further, the piezoelectric vibrators are laminated in a body
without using fixing means so as not to suppress the vibration and
to fix the vibrating direction, vibration loss of the respective
piezoelectric vibrators may be suppressed, the vibrating direction
may be prevented from varying and the structure of the device may
be simplified.
[0185] According to the invention as described in claim 2, driving
force in the both normal and reverse directions may be obtained and
the output may be controlled by displacing the bending vibration or
by changing the phase because the elliptic vibration for rotating
in the reverse direction is taken out by causing bending vibration
having a different phase or by amplifying the bending vibration by
exciting the second polarized portion with a phase different from
the first polarized portion in the same time.
[0186] According to the invention as described in claim 3, the
high-output ultrasonic motor may be realized because the stretching
vibration is amplified.
[0187] According to the invention as described in claim 4, the
high-output ultrasonic motor may be realized because the stretching
vibration is amplified.
[0188] According to the invention as described in claim 5, the
moving body may be moved in the horizontal direction of the
piezoelectric vibrator.
[0189] According to the invention as described in claim 6, the
spherical moving body may be moved arbitrary.
[0190] According to the invention as described in claim 7, the
electronic apparatus using the ultrasonic motor may be
realized.
[0191] While the preferred embodiments have been described,
variations thereto will occur to those skilled in the art within
the scope of the present inventive concepts which are delineated by
the following claims.
* * * * *