U.S. patent application number 12/439528 was filed with the patent office on 2010-01-28 for electrostatic operation device.
This patent application is currently assigned to Sanyo Electric Co., Ltd.. Invention is credited to Kazunari Honma, Naoteru Matsubara, Yohko Naruse, Yoshinori Shishida, Eiji Yuasa.
Application Number | 20100019616 12/439528 |
Document ID | / |
Family ID | 39135693 |
Filed Date | 2010-01-28 |
United States Patent
Application |
20100019616 |
Kind Code |
A1 |
Naruse; Yohko ; et
al. |
January 28, 2010 |
ELECTROSTATIC OPERATION DEVICE
Abstract
An electrostatic operation device in which a variation in the
amount of electric charges accumulated in an electret film caused
by physical impact can be suppressed. The electrostatic operation
device (electrostatic induction power generating device (1))
comprises movable electrodes (8), an electret film (5) so formed as
to face the movable electrodes (8) at a space therebetween, and a
stopper (401b) for suppressing the approach of the movable
electrodes (8) to the electret film (5) within a predetermined
space.
Inventors: |
Naruse; Yohko; (Aichi,
JP) ; Shishida; Yoshinori; (Gifu, JP) ;
Matsubara; Naoteru; (Aichi, JP) ; Honma;
Kazunari; (Gifu, JP) ; Yuasa; Eiji; (Gunma,
JP) |
Correspondence
Address: |
DITTHAVONG MORI & STEINER, P.C.
918 Prince Street
Alexandria
VA
22314
US
|
Assignee: |
Sanyo Electric Co., Ltd.
Moriguchi-shi
JP
|
Family ID: |
39135693 |
Appl. No.: |
12/439528 |
Filed: |
July 31, 2007 |
PCT Filed: |
July 31, 2007 |
PCT NO: |
PCT/JP07/64945 |
371 Date: |
February 28, 2009 |
Current U.S.
Class: |
310/300 |
Current CPC
Class: |
H02N 1/08 20130101; H01G
7/023 20130101; H02N 1/006 20130101 |
Class at
Publication: |
310/300 |
International
Class: |
H02N 1/00 20060101
H02N001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2006 |
JP |
2006-234811 |
Claims
1. An electrostatic operation device comprising: a first electrode
(8, 8a, 24, 24a, 62, 93); an electret film (5, 5a, 13, 43, 43a to
43i, 91) so formed as to be opposed to said first electrode at an
interval therebetween; and a member (9, 9a, 14, 14a to 14c, 42, 94,
94a, 94b, 96a to 96c, 401b, 412a to 412f, 413c, 612d) inhibiting
said first electrode and said electret film from moving close to
each other within a prescribed interval.
2. The electrostatic operation device according to claim 1, further
comprising a second electrode (4, 4a, 12, 41, 41a to 41f, 90) so
provided as to be opposed to said first electrode at an interval
therebetween.
3. The electrostatic operation device according to claim 2, wherein
an end of a surface of said member on a side of one of said first
electrode and said second electrode is chamfered.
4. The electrostatic operation device according to claim 2, further
comprising a first substrate (21, 21b) formed with said first
electrode and a second substrate (11) formed with said second
electrode, wherein said member is formed on a surface of one of
said first substrate and said second substrate.
5. The electrostatic operation device according to claim 2, further
comprising a first substrate (92) formed with said first electrode,
wherein said member is provided on a position between said first
substrate and said second electrode at intervals from said first
substrate and said second electrode.
6. The electrostatic operation device according to claim 2, further
comprising a protective film (97) formed to cover a surface not
formed with said electret film in the surfaces of said first and
second electrodes.
7. The electrostatic operation device according to claim 1, wherein
said member has a function as a stopper inhibiting said first
electrode and said electret film from coming into contact with each
other or a spacer keeping an interval between said first electrode
and said electret film constant.
8. The electrostatic operation device according to claim 1, further
comprising a guard electrode (15, 15a) for inhibiting a component
other than a component in a direction perpendicular to a main
surface of said electret film in an electric field resulting from
electric charges stored in said electret film from generation,
provided to be adjacent to said electret film.
9. The electrostatic operation device according to claim 8, further
comprising a second electrode so provided as to be opposed to said
first electrode at an interval therebetween, wherein said member is
so formed as to be stacked on a surface of said guard electrode on
a side of one of said first electrode and said second
electrode.
10. The electrostatic operation device according to claim 1,
wherein said member inhibiting said first electrode and said
electret film from moving close to each other within the prescribed
interval functions as a guard electrode for inhibiting a component
other than a component in a direction perpendicular to a main
surface of said electret film in an electric field resulting from
electric charges stored in said electret film from generation,
provided to be adjacent to said electret film.
11. The electrostatic operation device according to claim 1,
further comprising a first substrate (21a) formed with said first
electrode, wherein said first electrode is embedded in said first
substrate.
12. The electrostatic operation device according to claim 1,
wherein said member is formed between said electret film and said
first electrode.
13. The electrostatic operation device according to claim 1,
further comprising a first substrate formed with said first
electrode, wherein said first substrate is supported by said member
to be able to vibrate.
14. The electrostatic operation device according to claim 1,
further comprising a second substrate (90) formed with said
electret film, wherein said second substrate is supported by said
member to be able to vibrate.
15. The electrostatic operation device according to claim 1,
further comprising a groove shaped recess portion (401a, 411a to
411f, 421) and a projecting portion (401b, 412a to 412f) provided
on a surface of one of said first electrode and said second
electrode, wherein said electret film is so formed as to be
embedded in at least a bottom surface of said recess portion.
16. The electrostatic operation device according to claim 15,
wherein said groove shaped recess portion is so formed that a width
is increased from a bottom surface of said recess portion toward an
open upper end thereof.
17. The electrostatic operation device according to claim 15,
wherein a conductive layer is formed on a surface of said
projecting portion.
18. The electrostatic operation device according to claim 15,
wherein an insulating film (45a, 45b) having a smaller breakdown
voltage than said electret film is formed on a surface of said
projecting portion.
19. The electrostatic operation device according to claim 15,
wherein said electret film is formed on the bottom surface of said
recess portion to have a thickness smaller than a depth of said
recess portion.
20. The electrostatic operation device according to claim 15,
wherein an end of a surface of said projecting portion on a side of
one of said first electrode and said second electrode is formed in
a rounded shape or a chamfered shape.
21. The electrostatic operation device according to claim 15,
wherein a charge outflow inhibition film (46, 48) is formed on a
surface of said electret film.
22. The electrostatic operation device according to claim 15,
wherein said electret film formed to be embedded in said groove
shaped recess portion is oblongly formed in plan view.
23. The electrostatic operation device according to claim 1,
wherein said member is formed on a surface of said electret
film.
24. The electrostatic operation device according to claim 23,
wherein at least a part of said member is formed by a member softer
than said electret film.
25. The electrostatic operation device according to claim 23,
further comprising a conductive layer (10) formed on a surface of
said member.
26. The electrostatic operation device according to claim 23,
wherein said member is so formed that a width is reduced toward a
side on which said electret film is not formed.
27. An electrostatic operation device comprising: a first electrode
(62); a second electrode (62a) provided to be adjacent to said
first electrode at an interval therebetween; an electret film (5b)
formed to be opposed to said first electrode and said second
electrode; and a member (9b) having a function as a stopper
inhibiting said first and second electrodes and said electret film
from coming into contact with each other or a spacer keeping an
interval between said first and second electrodes and said electret
film constant, between said first and second electrodes and said
electret film.
28. An electrostatic operation device comprising: a first electrode
(62); a second electrode (62a) provided to be adjacent to said
first electrode at an interval therebetween; a substrate (4b) to be
opposed to said first electrode and said second electrode and
provided with a projecting portion (401c) and a recess portion
(401d); and an electret film (5b) formed to be embedded in a bottom
surface of said recess portion provided on said substrate, wherein
said projecting portion provided on said substrate has a function
as a stopper inhibiting said first and second electrodes and said
electret film from coming into contact with each other or a spacer
keeping an interval between said first and second electrodes and
said electret film constant.
Description
TECHNICAL FIELD
[0001] The present invention relates to an electrostatic operation
device, and more particularly, it relates to an electrostatic
operation device comprising an electret film.
BACKGROUND ART
[0002] Japanese National Patent Publication Gazette No. 2005-529574
discloses an electrostatic operation device (electrostatic
induction power generating device) comprising an electret film is
known. This electrostatic induction power generating device
disclosed in Japanese National Patent Publication Gazette No.
2005-529574 is constituted by a movable electrode, a fixed
electrode and an electret film made of a charge holding material of
a resin material such as Teflon (registered trademark) formed on
the fixed electrode. In this electrostatic induction power
generating device, the movable electrode repeatedly vibrates by
receiving inertial force, so that electric charges induced in the
movable electrode with electric charges stored in the electret film
are changed to output the changed amount of electric charges as a
current.
[0003] In the aforementioned electrostatic induction power
generating device employing the electret film, however, the
electrostatic induction power generating device receives a physical
impact and the movable electrode and the electret film come into
physical contact with each other, whereby the amount of electric
charges stored in the electret film is disadvantageously
changed.
DISCLOSURE OF THE INVENTION
[0004] The present invention has been proposed in order to solve
the aforementioned problems, and an object of the present invention
is to provide an electrostatic operation device capable of
inhibiting the amount of electric charges stored in an electret
film from change due to a physical impact.
[0005] An electrostatic operation device according to a first
aspect of the present invention comprises a first electrode, an
electret film so formed as to be opposed to the first electrode at
an interval therebetween and a member inhibiting the first
electrode and the electret film from moving close to each other
within a prescribed interval.
[0006] As hereinabove described, this electrostatic operation
device according to the first aspect comprises the member
inhibiting the first electrode and the electret film from moving
close to each other within the prescribed interval, whereby the
first electrode and the electret film can be inhibited from coming
into contact with each other due to a physical impact, and hence
the amount of electric charges stored in the electret film can be
inhibited from change due to contact between the first electrode
and the electret film.
[0007] The aforementioned electrostatic operation device according
to the first aspect preferably further comprises a second electrode
so provided as to be opposed to the first electrode at an interval
therebetween. According to this structure, the first electrode and
the second electrode are electrically connected to each other,
whereby electrostatic induction is caused in the first electrode
and the second electrode by electric charges stored in the electret
film. This potential difference between the first electrode and the
second electrode is extracted, whereby power can be generated.
[0008] In this case, an end of a surface of the member on a side of
one of the first electrode and the second electrode is preferably
chamfered. According to this structure, the end of the surface of
the member on the side of the first electrode has a smooth shape,
and hence the first electrode can be inhibited from catching the
member when the first electrode is moving by vibration.
[0009] The aforementioned electrostatic operation device comprising
the first electrode and the second electrode preferably further
comprises a first substrate formed with the first electrode and a
second substrate formed with the second electrode, wherein the
member is preferably formed on a surface of one of the first
substrate and the second substrate. According to this structure,
the first and second electrodes and the electret film can be easily
inhibited from coming into contact with each other.
[0010] The aforementioned electrostatic operation device comprising
the first electrode and the second electrode preferably further
comprises a first substrate formed with the first electrode,
wherein the member may be provided on a position between the first
substrate and the second electrode at intervals from the first
substrate and the second electrode.
[0011] The aforementioned electrostatic operation device comprising
the first electrode and the second electrode preferably further
comprises a protective film formed to cover a surface not formed
with the electret film in the surfaces of the first and second
electrodes. According to this structure, the protective film can
inhibit the surface not formed with the electret film in the
surfaces of the first and second electrodes from coming into
contact with the electret film.
[0012] In the aforementioned electrostatic operation device
according to the first aspect, the member preferably has a function
as a stopper inhibiting the first electrode and the electret film
from coming into contact with each other or a spacer keeping an
interval between the first electrode and the electret film
constant. According to this structure, the member is employed as
the stopper, whereby the first electrode and the electret film can
be easily inhibited from coming into contact with each other.
Further, the member is employed as the spacer, whereby the interval
between the first electrode and the electret film can be kept
constant.
[0013] The aforementioned electrostatic operation device according
to the first aspect preferably further comprises a guard electrode
for inhibiting a component other than a component in a direction
perpendicular to a main surface of the electret film in an electric
field resulting from electric charges stored in the electret film
from generation, provided to be adjacent to the electret film.
According to this structure, the electric field can be inhibited
from reaching a position not opposed to the main surface of the
electret film and hence difference in potentials between a
potential at a position opposed to the main surface of the electret
film and a potential at the position not opposed to the electret
film can be increased. Thus, difference between the amount of
electric charges stored in the first electrode by electrostatic
induction in a case where the first electrode is at the position
opposed to the electret film and the amount of electric charges
stored in the first electrode by electrostatic induction in a case
where the first electrode is at the position not opposed to the
electret film can be increased. Consequently, the amount of power
generation can be increased.
[0014] In this case, the electrostatic operation device preferably
further comprises a second electrode so provided as to be opposed
to the first electrode at an interval therebetween, wherein the
member is so formed as to be stacked on a surface of the guard
electrode on a side of one of the first electrode and the second
electrode. According to this structure, a planar region on the
surface of the fixed substrate for arranging the member and the
guard electrode is reduced as compared with a case where the member
and the guard electrode are arranged on different planar positions
without being stacked with each other, and hence size in the
electrostatic operation device can be reduced.
[0015] In the aforementioned electrostatic operation device
according to the first aspect, the member inhibiting the first
electrode and the electret film from coming into contact with each
other preferably functions as a guard electrode for inhibiting a
component other than a component in a direction perpendicular to a
main surface of the electret film in an electric field resulting
from electric charges stored in the electret film from generation,
provided to be adjacent to the electret film. According to this
structure, the member inhibiting the first electrode and the
electret film from coming into contact with each other functions
also as the guard electrode and hence the number of components can
be reduced dissimilarly to a case where the member and the guard
electrode are separately formed.
[0016] The aforementioned electrostatic operation device according
to the first aspect preferably further comprises a first substrate
formed with the first electrode, wherein the first electrode is
embedded in the first substrate. According to this structure, the
surface of the first substrate has no irregularities and hence the
first electrode can be inhibited from coming into contact with and
catching the member when the first electrode is moving by
vibration.
[0017] In the aforementioned electrostatic operation device
according to the first aspect, the member is preferably formed
between the electret film and the first electrode. According to
this structure, the electret film and the first electrode can be
easily inhibited from coming into contact with each other and the
interval between the electret film and the first electrode can be
kept at a prescribed interval or more.
[0018] The aforementioned electrostatic operation device according
to the first aspect further may comprise a first substrate formed
with the first electrode, wherein the first substrate may be
supported by the member to be able to vibrate.
[0019] The aforementioned electrostatic operation device according
to the first aspect further may comprise a second substrate formed
with the electret film, wherein the second substrate may be
supported by the member to be able to vibrate.
[0020] The aforementioned electrostatic operation device according
to the first aspect preferably further comprises a groove shaped
recess portion and a projecting portion provided on a surface of
one of said first electrode and said second electrode, wherein the
electret film is preferably so formed as to be embedded in at least
a bottom surface of the recess portion. According to this
structure, the projecting portion can inhibit the other of the
first and second electrodes and the electret film from coming into
contact with each other, and hence the amount of electric charges
stored in the electret film can be inhibited from change.
[0021] In this case, the groove shaped recess portion is so formed
that a width is preferably increased from a bottom surface of the
recess portion toward an open upper end thereof. According to this
structure, side surfaces of the recess portion are inclined and
hence the other of the first electrode and the second electrode can
be inhibited from catching the side surfaces of the recess
portion.
[0022] In the aforementioned electrostatic operation device where
the electret film is so formed as to be embedded in at least the
bottom surface of the recess portion, a conductive layer is
preferably formed on a surface of the projecting portion. According
to this structure, the conductive layer can inhibit a component
other than a component in a direction perpendicular to a main
surface of the electret film in an electric field resulting from
electric charges stored in the electret film from generation, and
hence the electric field can be inhibited from reaching a position
not opposed to the main surface of the electret film. Thus,
difference between a potential of a position opposed to the main
surface of the electret film and a potential of the position not
opposed to the electret film can be increased, and hence difference
between the amount of electric charges stored in the other of the
first electrode and the second electrode by electrostatic induction
in a case where the other of the first electrode and the second
electrode is at the position opposed to the electret film and the
amount of electric charges stored in the other of the first
electrode and the second electrode by electrostatic induction in a
case where the other of the first electrode and the second
electrode is at the position not opposed to the electret film can
be increased. Consequently, the amount of power generation can be
increased.
[0023] In the aforementioned electrostatic operation device where
the electret film is so formed as to be embedded in at least the
bottom surface of the recess portion, an insulating film having a
smaller breakdown voltage than the electret film is preferably
formed on a surface of the projecting portion. According to this
structure, even when the electret film and the insulating film are
simultaneously made electret, the insulating film first causes
dielectric breakdown due to the smaller breakdown voltage of the
insulating film than the electret film, and hence the electret film
can store a larger number of electric charges and the amounts of
electric charges stored in the electret film and the insulating
film are made different from each other. Thus, an intensity of an
electric field on a surface of the electret film and an intensity
of an electric field on a surface of the insulating film can be
made different from each other.
[0024] In the aforementioned electrostatic operation device where
the electret film is so formed as to be embedded in at least the
bottom surface of the recess portion, the electret film is
preferably formed on the bottom surface of the recess portion to
have a thickness smaller than a depth of the recess portion.
According to this structure, the electret film does not protrude
from an opening of the recess portion and hence the electret film
and the other of the first electrode and the second electrode can
be inhibited from coming into contact with each other.
[0025] In the aforementioned electrostatic operation device where
the electret film is so formed as to be embedded in at least the
bottom surface of the recess portion, an end of a surface of the
projecting portion on a side of one of the first electrode and the
second electrode is preferably formed in a rounded shape or a
chamfered shape. According to this structure, the projecting
portion and the other of the first electrode and the second
electrode can be easily inhibited from coming into contact with
each other.
[0026] In the aforementioned electrostatic operation device where
the electret film is so formed as to be embedded in at least the
bottom surface of the recess portion, a charge outflow inhibition
film is preferably formed on a surface of the electret film.
According to this structure, electric charges can be easily
inhibited from flowing out of the electret film.
[0027] In the aforementioned electrostatic operation device where
the electret film is so formed as to be embedded in at least the
bottom surface of the recess portion, the electret film formed to
be embedded in the groove shaped recess portion is preferably
oblongly formed in plan view. According to this structure, an
intensity of an electric field on a surface of the electret film
and an intensity of an electric field on a surface of a region not
formed with the electret film can be easily made different from
each other.
[0028] In the aforementioned electrostatic operation device
according to the first aspect, the member is preferably formed on a
surface of the electret film. According to this structure, a width
of the electrostatic operation device can be reduced by a width of
the member dissimilarly to a case where the member is formed around
the electret film.
[0029] In this case, at least a part of the member is preferably
formed by a member softer than the electret film. According to this
structure, the member is deformed to absorb an impact even when an
impact is applied to the member, and hence deformation of the
electret film can be suppressed. Further, the member is formed by
an elastic member, whereby the member can be inhibited from
breakage even when an impact is applied to the member, and hence
reduction in a surface potential resulting from deposition of
fragments of the member caused by breakage on the surface of the
electret film can be suppressed. The fragments of the member are
deposited on the surface of the electret film, whereby an electric
field on the surface of the electret film can be inhibited from
hindering.
[0030] The aforementioned electrostatic operation device where the
member is formed on the surface of the electret film preferably
further comprises a conductive layer formed on a surface of the
member. According to this structure, injection of electric charges
into the member can be suppressed by the conductive layer when
electric charges are injected into the electret film by corona
discharge.
[0031] In the aforementioned electrostatic operation device where
the member is formed on the surface of the electret film, the
member is preferably so formed that a width is reduced toward a
side on which the electret film is not formed. According to this
structure, friction between the other of the first and second
electrodes and the member can be reduced when the other of the
first electrode and the second electrode comes into contact with
the member dissimilarly to a case where the width of the member
does not vary.
[0032] An electrostatic operation device according to a second
aspect of the present invention comprises a first electrode, a
second electrode provided to be adjacent to the first electrode at
an interval therebetween, an electret film formed to be opposed to
the first electrode and the second electrode and a member having a
function as a stopper inhibiting the first and second electrodes
and the electret film from coming into contact with each other or a
spacer keeping an interval between the first and second electrodes
and the electret film constant, between the first and second
electrodes and the electret film.
[0033] As hereinabove described, this electrostatic operation
device according to the second aspect comprises the member as the
stopper inhibiting the first and second electrodes and the electret
film from coming into contact with each other, whereby the first
and second electrodes and the electret film can be inhibited from
coming into contact with each other due to a physical impact, and
hence the amount of electric charges stored in the electret film
can be inhibited from change due to contact between the first and
second electrodes and the electret film. Further, the electrostatic
operation device comprises the member as the spacer keeping the
interval between the first and second electrodes and the electret
film constant, whereby the interval between the first and second
electrodes and the electret film can be kept constant and hence the
amount of power generation can be stabilized.
[0034] An electrostatic operation device according to a third
aspect of the present invention comprises a first electrode, a
second electrode provided to be adjacent to the first electrode at
an interval therebetween, a substrate to be opposed to the first
electrode and the second electrode and provided with a projecting
portion and a recess portion, and an electret film formed to be
embedded in a bottom surface of the recess portion provided on the
substrate, wherein the projecting portion provided on the substrate
has a function as a stopper inhibiting the first and second
electrodes and the electret film from coming into contact with each
other or a spacer keeping an interval between the first and second
electrodes and the electret film constant.
[0035] In this electrostatic operation device according to the
third aspect, as hereinabove described, the projecting portion of
the substrate has the function as the stopper to inhibit the first
and second electrodes and the electret film from coming into
contact with each other, whereby the first and second electrodes
and the electret film can be inhibited from coming into contact
with each other due to a physical impact, and hence the amount of
electric charges stored in the electret film can be inhibited from
change due to contact between the first and second electrodes and
the electret film. The projecting portion of the substrate has the
function as the spacer keeping the interval between the first and
second electrodes and the electret film constant, whereby the
interval between the first and second electrodes and the electret
film can be kept constant and hence the amount of power generation
can be stabilized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] [FIG. 1] A sectional view of an electrostatic induction
power generating device according to a first embodiment of the
present invention.
[0037] [FIG. 2] A sectional view taken along the line 100-100 in
FIG. 1.
[0038] [FIG. 3] A sectional view taken along the line 110-110 in
FIG. 1.
[0039] [FIG. 4] A sectional view of an electrostatic induction
power generating device according to a second embodiment of the
present invention.
[0040] [FIG. 5] A sectional view of an electrostatic induction
power generating device according to a third embodiment of the
present invention.
[0041] [FIG. 6] A sectional view taken along the line 120-120 in
FIG. 5.
[0042] [FIG. 7] A sectional view taken along the line 130-130 in
FIG. 5.
[0043] [FIG. 8] A sectional view of an electrostatic induction
power generating device according to a fourth embodiment of the
present invention.
[0044] [FIG. 9] A sectional view of a fixed electrode portion of an
electrostatic induction power generating device according to a
fifth embodiment of the present invention.
[0045] [FIG. 10] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
sixth embodiment of the present invention.
[0046] [FIG. 11] A sectional view of an electrostatic induction
power generating device according to a seventh embodiment of the
present invention.
[0047] [FIG. 12] A sectional view taken along the line 140-140 in
FIG. 11.
[0048] [FIG. 13] A sectional view taken along the line 150-150 in
FIG. 11.
[0049] [FIG. 14] A sectional view for illustrating a power
generating operation of the electrostatic induction power
generating device according to the seventh embodiment of the
present invention.
[0050] [FIG. 15] A sectional view of an electrostatic induction
power generating device according to an eighth embodiment of the
present invention.
[0051] [FIG. 16] A diagram showing a condition of an
electromagnetical field simulation for confirming effects of guard
electrodes according to the eighth embodiment.
[0052] [FIG. 17] A diagram showing lines of electric force by
electric charges stored in the electret film.
[0053] [FIG. 18] A sectional view of an electrostatic induction
power generating device according to a ninth embodiment of the
present invention.
[0054] [FIG. 19] A sectional view of an electrostatic induction
power generating device according to a tenth embodiment of the
present invention.
[0055] [FIG. 20] A sectional view of an electrostatic induction
power generating device according to an eleventh embodiment of the
present invention.
[0056] [FIG. 21] A sectional view of an electrostatic induction
power generating device according to a twelfth embodiment of the
present invention.
[0057] [FIG. 22] A sectional view of an electrostatic induction
power generating device according to a thirteenth embodiment of the
present invention.
[0058] [FIG. 23] A sectional view taken along the line 160-160 in
FIG. 22.
[0059] [FIG. 13] A sectional view taken along the line 170-170 in
FIG. 22.
[0060] [FIG. 25] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
fourteenth embodiment of the present invention.
[0061] [FIG. 26] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
fifteenth embodiment of the present invention.
[0062] [FIG. 27] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
sixteenth embodiment of the present invention.
[0063] [FIG. 28] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
seventeenth embodiment of the present invention.
[0064] [FIG. 29] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to an
eighteenth embodiment of the present invention.
[0065] [FIG. 30] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
nineteenth embodiment of the present invention.
[0066] [FIG. 31] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
twentieth embodiment of the present invention.
[0067] [FIG. 32] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
twenty-first embodiment of the present invention.
[0068] [FIG. 33] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
twenty-second embodiment of the present invention.
[0069] [FIG. 34] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
twenty-third embodiment of the present invention.
[0070] [FIG. 35] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
twenty-fourth embodiment of the present invention.
[0071] [FIG. 36] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
twenty-fifth embodiment of the present invention.
[0072] [FIG. 37] A sectional view of an electrostatic induction
power generating device according to a twenty-sixth embodiment of
the present invention.
[0073] [FIG. 38] A sectional view of an electrostatic induction
power generating device according to a twenty-seventh embodiment of
the present invention.
[0074] [FIG. 39] A sectional view of an electrostatic induction
power generating device according to a twenty-eighth embodiment of
the present invention.
[0075] [FIG. 40] A sectional view taken along the line 180-180 in
FIG. 39.
[0076] [FIG. 41] A sectional view of an electrostatic induction
power generating device according to a twenty-ninth embodiment of
the present invention.
[0077] [FIG. 42] A sectional view of an electrostatic induction
power generating device according to a thirtieth embodiment of the
present invention.
[0078] [FIG. 43] A sectional view of an electrostatic induction
power generating device according to a thirty-first embodiment of
the present invention.
[0079] [FIG. 44] A sectional view of an electrostatic induction
power generating device according to a thirty-first embodiment of
the present invention.
[0080] [FIG. 45] A sectional view taken along the line 190-190 in
FIG. 43.
[0081] [FIG. 46] A sectional view of an electrostatic induction
power generating device according to a thirty-second embodiment of
the present invention.
[0082] [FIG. 47] A sectional view taken along the line 200-200 in
FIG. 46.
[0083] [FIG. 48] A sectional view of an electrostatic induction
power generating device according to a thirty-third embodiment of
the present invention.
[0084] [FIG. 49] A sectional view taken along the line 210-210 in
FIG. 48.
[0085] [FIG. 50] A sectional view of an electrostatic induction
power generating device according to a thirty-fourth embodiment of
the present invention.
[0086] [FIG. 51] A sectional view of an electrostatic induction
power generating device according to a thirty-fifth embodiment of
the present invention.
[0087] [FIG. 52] A sectional view of an electrostatic induction
power generating device according to a thirty-sixth embodiment of
the present invention.
[0088] [FIG. 53] A sectional view of a movable electrode portion
according to a thirty-seventh embodiment of the present
invention.
[0089] [FIG. 54] A sectional view of an electrostatic induction
power generating device according to a thirty-eighth embodiment of
the present invention.
[0090] [FIG. 55] A sectional view of an electrostatic induction
power generating device according to a thirty-ninth embodiment of
the present invention.
[0091] [FIG. 56] A sectional view of an electrostatic induction
power generating device according to a fortieth embodiment of the
present invention.
[0092] [FIG. 57] A sectional view of an electrostatic induction
power generating device according to a forty-first embodiment of
the present invention.
[0093] [FIG. 58] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
modification of the fifteenth embodiment of the present
invention.
[0094] [FIG. 59] A sectional view of an electrostatic induction
power generating device according to a first modification of the
first embodiment of the present invention.
[0095] [FIG. 60] A sectional view of an electrostatic induction
power generating device according to a second modification of the
first embodiment of the present invention.
[0096] [FIG. 61] A sectional view of an electrostatic induction
power generating device according to a third modification of the
first embodiment of the present invention.
[0097] [FIG. 62] A sectional view of an electrostatic induction
power generating device according to a fourth modification of the
first embodiment of the present invention.
[0098] [FIG. 63] A sectional view of an electrostatic induction
power generating device according to a modification of the
thirty-eighth embodiment of the present invention.
[0099] [FIG. 64] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
modification of the seventeenth embodiment of the present
invention.
[0100] [FIG. 65] A sectional view of a fixed electrode portion of
an electrostatic induction power generating device according to a
modification of each of the seventh to twelfth embodiments of the
present invention.
BEST MODES FOR CARRYING OUT THE INVENTION
[0101] Embodiments of the present invention will be hereinafter
described with reference to the drawings.
First Embodiment
[0102] A structure of an electrostatic induction power generating
device 1 according to a first embodiment will be described with
reference to FIGS. 1 to 3. The first embodiment of the present
invention is applied to the electrostatic induction power
generating device 1 employed as an exemplary electrostatic
operation device.
[0103] The electrostatic induction power generating device 1
according to the first embodiment is constituted by a fixed
electrode portion 2 and a movable electrode portion 3, as shown in
FIG. 1. The first embodiment will be now described in detail.
[0104] As shown in FIG. 1, in the fixed electrode portion 2, a
groove shaped recess portion 401a and a projecting portion 401b for
inhibiting an electret film 5 and a movable electrode 8, described
later, from coming into contact with each other are formed on a
surface of a fixed electrode 4 made of silicon. The fixed electrode
4 is an example of the "second electrode" in the present invention.
The projecting portion 401b is an example of the "member" in the
present invention. According to the first embodiment, the
projecting portion 401b has a function as a stopper inhibiting the
movable electrode 8 and the electret film 5 from coming into
contact with each other. As shown in FIG. 2, the groove shaped
recess portion 401a is rectangularly formed. The rectangular
electret film 5 made of an organic material such as PTFE or a
silicon oxide film, having a thickness of about 0.1 .mu.m to about
50 .mu.m is so formed as to fill up a bottom surface of the groove
shaped recess portion 401a. The interdigital conductive layer 6 is
formed on an upper surface of the electret film 5.
[0105] As shown in FIG. 1, in the movable electrode portion 3, the
movable electrode 8 is so formed on a surface of a movable
substrate 7 made of quartz as to be opposed to the electret film 5.
The movable electrode 8 is an example of the "first electrode" in
the present invention. As shown in FIG. 3, the movable electrode 8
is interdigitally formed.
[0106] A power generating operation of the electrostatic induction
power generating device 1 according to the first embodiment of the
present invention will be now described with reference to FIG.
1.
[0107] When no vibration is applied to the electrostatic induction
power generating device 1, the electret film 5 and the movable
electrode 8 are arranged to be opposed to each other at a
prescribed interval, as shown in FIG. 1. At this time, positive
electric charges or negative electric charges are stored in the
surface of the electret film 5. Charges opposite to the electric
charges stored in the electret film 5 on a side of the movable
electrode 8 are induced in the movable electrode 8 by electrostatic
induction.
[0108] Then, the movable electrode 8 moves to a position opposed to
the conductive layer 6 from a position opposed to the electret film
5 shown in FIG. 1 by applying horizontal vibration (in a direction
X) to the electrostatic induction power generating device 1 and
moving the movable electrode 8 in the direction X. Thus,
electrostatic force running to the movable electrode 8 is reduced,
and hence the amount of electric charges induced in the movable
electrode 8 is reduced. Thereafter the electrostatic induction
power generating device 1 vibrates in the horizontal direction
(direction X), so that the amount of the electric charges induced
in the movable electrode 8 is increased when the electret film 5
and the movable electrode 8 are at the opposed position shown in
FIG. 1. This changed amount of the electric charges induced in the
movable electrode 8 is extracted as a current, so that the
electrostatic induction power generating device 1 can generate
power.
[0109] According to the first embodiment, as hereinabove described,
the electrostatic induction power generating device 1 comprises the
projecting portion 401b for inhibiting the movable electrode 8 and
the electret film 5 from coming into contact with each other,
whereby the movable electrode 8 can be inhibited from moving in a
direction Z (vertical direction) shown in FIG. 1 by a physical
impact and coming into contact with the electret film 5, and hence
the amount of electric charges stored in the electret film 5 can be
inhibited from change due to contact between the movable electrode
8 and the electret film 5. Further, the fixed electrode 4 and the
projecting portion 401b are integrally formed, whereby adhesion
between the fixed electrode 4 and the projecting portion 401b is
excellent and hence the fixed electrode 4 and the projecting
portion 401b can be inhibited from separation even when force by
the contact between the movable electrode 8 and the electret film 5
in vibration is applied to the projecting portion 401b.
Additionally, the fixed electrode 4 and the projecting portion 401b
are integrally formed, whereby the number of components can be
reduced dissimilarly to a case where the fixed electrode 4 and the
projecting portion 401b are formed by different members.
Second Embodiment
[0110] Referring to FIG. 4, an electrostatic induction power
generating device 1a where a movable substrate 7 is in contact with
a projecting portion 401b will be described in this second
embodiment dissimilarly to the aforementioned first embodiment.
[0111] In an electrostatic induction power generating device la
according to this second embodiment, the projecting portion 401b
provided on a fixed electrode 4 is formed in contact with the
movable substrate 7 as shown in FIG. 4.
[0112] According to the second embodiment, the projecting portion
401b has a function as a stopper inhibiting the movable electrode 8
and the electret film 5 from coming into contact with each other
and also has a function as a spacer keeping an interval between the
movable electrode 8 and the electret film 5 constant. The remaining
structure of the second embodiment is similar to that of the
aforementioned first embodiment.
[0113] The effects of the second embodiment are similar to those of
the aforementioned first embodiment.
Third Embodiment
[0114] Referring to FIGS. 5 to 7, an electrostatic induction power
generating device b where stopper films 9 are formed on a surface
of an electret film 5a will be described in this third embodiment
dissimilar to the aforementioned first embodiment.
[0115] In a fixed electrode portion 2a according to this third
embodiment, the electret film 5a is formed on a surface of a fixed
electrode 4a as shown in FIG. 5. The fixed electrode 4a is an
example of the "second electrode" in the present invention. As
shown in FIGS. 5 and 6, oblong conductive layer 6a is formed on a
surface of the electret film 5a. According to the third embodiment,
the stopper films 9 formed by an insulating film such as a plasma
silicon oxide film or a plasma silicon nitride film softer than the
electret film 5a, a tape constituted by a substrate and an adhesive
material, a conductive material and combination of these are formed
to be adjacent to the conductive layer 6a. The stopper films 9 are
examples of the "member" in the present invention. A height of each
of the stopper films 9 is formed to be larger than that of the
conductive layer 6a. A charge outflow inhibition film made of MSQ
may be formed on a surface of the electret film 5a.
[0116] As shown in FIGS. 5 and 7, a movable electrode 8a is formed
on a surface of a movable substrate 7. As shown in FIG. 7, the
movable electrode 8a is oblongly formed.
[0117] As shown in FIG. 5, in an electrostatic induction power
generating device 1b according to the third embodiment, the fixed
electrode 4a and the movable electrode 8a relatively move in a
direction Y, thereby generating power.
[0118] According to the third embodiment, as hereinabove described,
the stopper films 9 are formed on the surface of the electret film
5a, whereby a width of the electrostatic induction power generating
device 1b can be reduced by a width of the stopper films 9
dissimilarly to a case of forming the stopper films 9 around the
electret film 5a. The stopper films 9 are formed by the insulating
film such as a plasma oxide film or a plasma nitride film softer
(having a Young's modulus lower) than the electret film 5a or the
tape constituted by a substrate and an adhesive material, whereby
the stopper films 9 are deformed to absorb an impact even when the
impact is applied to the stopper films 9, and hence deformation of
the electret film 5a can be suppressed. Further, the stopper films
9 are formed by an elastic member, whereby the stopper films 9 can
be inhibited from breakage even when an impact is applied to the
stopper films 9, and hence reduction in a surface potential
resulting from deposition of fragments of the stopper films 9
caused by breakage on the surface of the electret film 5a can be
suppressed. The fragments of the stopper films 9 are deposited on
the surface of the electret film 5a, whereby an electric field on
the surface of the electret film 5a can be inhibited from
hindering.
Fourth Embodiment
[0119] Referring to FIG. 8, an electrostatic induction power
generating device 1c where a movable substrate 7 is in contact with
stopper films 9 will be described in this fourth embodiment
dissimilarly to the aforementioned third embodiment.
[0120] In an electrostatic induction power generating device 1c
according to this fourth embodiment, the stopper films 9 provided
on a surface of an electret film 5a are formed in contact with the
movable substrate 7 as shown in FIG. 8. The remaining structure of
the fourth embodiment is similar to that of the aforementioned
third embodiment.
[0121] The effects of the fourth embodiment are similar to those of
the aforementioned third embodiment.
Fifth Embodiment
[0122] Referring to FIG. 9, a fixed electrode portion 2b where
conductive layers 10 are formed on surfaces of stopper films 9 will
be described in this fifth embodiment dissimilarly to the
aforementioned third embodiment.
[0123] In the fixed electrode portion 2b according to this fifth
embodiment, conductive layers 10 are formed on the surfaces of the
stopper films 9 as shown in FIG. 9. The remaining structure of the
fifth embodiment is similar to that of the aforementioned third
embodiment.
[0124] According to the fifth embodiment, as hereinabove described,
the conductive layers 10 are formed on the surfaces of the stopper
films 9, whereby injection of electric charges into the stopper
films 9 can be suppressed by the conductive layers 10 when electric
charges are injected into the electret film 5a by corona discharge.
Thus, electrostatic force exerted on the movable electrode 8a can
be suppressed by the stopper films 9.
Sixth Embodiment
[0125] Referring to FIG. 10, a fixed electrode portion 2c where
stopper films 9a are so formed that widths thereof are reduced
toward a side of a movable electrode 8a will be described in this
sixth embodiment dissimilarly to the aforementioned third
embodiment.
[0126] In the fixed electrode portion 2c according to this sixth
embodiment, the stopper films 9a are so formed that the widths
thereof are reduced toward the side of the movable electrode 8a
(see FIG. 5) as shown in FIG. 10. The stopper films 9a are examples
of the "member" in the present invention. The remaining structure
of the sixth embodiment is similar to that of the aforementioned
third embodiment.
[0127] According to the sixth embodiment, as hereinabove described,
the stopper films 9a are so formed that the widths thereof are
reduced toward the side of the movable electrode 8a, whereby
friction between the movable electrode 8a and the stopper films 9a
can be reduced when the movable electrode 8a and the stopper films
9a (see FIG. 5) come into contact with each other dissimilarly to a
case where the widths of the stopper films 9 do not vary.
Seventh Embodiment
[0128] Referring to FIGS. 11 to 13, a structure of an electrostatic
induction power generating device 1d according to a seventh
embodiment will be described.
[0129] The electrostatic induction power generating device 1d
according to this seventh embodiment is constituted by a fixed
substrate 11 made of glass, a movable substrate 21 made of glass
and a column portion 31 made of silicon as shown in FIG. 11. The
movable substrate 21 is mounted on a frame portion 23 through
spring portions 22 as shown in FIG. 13. The column portion 31 is
formed on an upper surface of the fixed substrate 11 and the frame
portion 23 is fixed on an upper surface of the column portion 31. A
detailed description will be made hereinafter.
[0130] As shown in FIGS. 11 and 12, an interdigital fixed electrode
12 made of Au or Al having a thickness of about 1 .mu.m and a width
W1 of about 100 .mu.m is formed on the upper surface of the fixed
substrate 11 made of glass having a thickness of about 0.5 mm. The
fixed electrode 12 is an example of the "second electrode" in the
present invention. An interdigital electret film 13 made of Teflon
(registered trademark) having a thickness of about 1 .mu.m and the
width W1 of about 100 .mu.m is so formed as to be stacked on the
upper surface of the fixed electrode 11. Charges are injected by
corona discharge so that the electret film 13 is controlled to a
potential of about 1000 V.
[0131] According to the seventh embodiment, an interdigital stopper
film 14 made of a silicon oxide film or a silicon nitride film
having a thickness of about 20 .mu.m and a width W2 of about 100
.mu.m is formed on the upper surface of the fixed substrate 11 to
be adjacent to the fixed electrode 12 at intervals D of about 10
.mu.m from the fixed electrode 12. The stopper film 14 is an
example of the "member" in the present invention. In other words,
the stopper film 14 is so formed as to have a thickness not causing
contact between a movable electrode 24, described later, and the
electret film 13 when the movable electrode 24 comes close to the
electret film 13 by vibration.
[0132] The electret film 13 and the fixed electrode 12 are opposed
to the stopper film 14 at an interval so that teeth forming the
interdigital electret film 13 and the interdigital fixed electrode
12 do not overlap with teeth forming the interdigital stopper film
14. The column portion 31 is formed along peripheral portions of
the fixed substrate 11 and the frame portion 23.
[0133] As shown in FIG. 11, the movable electrode 24 made of Au or
Al having a thickness of about 0.5 .mu.m and a width of about 100
.mu.m is formed on a lower surface of the movable substrate 21 made
of glass having a thickness of about 0.5 mm. The movable electrode
24 is an example of the "first electrode" in the present invention.
The fixed substrate 11 and the movable substrate 21 are set to be
opposed at an interval of about 30 .mu.m by the column portion
31.
[0134] As shown in FIG. 13, the movable electrode 24 is
interdigitally formed similarly to the electret film 13 and the
fixed electrode 12 shown in FIG. 12. As shown in FIG. 11, the
electret film 13 and the movable electrode 24 are arranged to be
opposed to each other when no vibration is applied to the
electrostatic induction power generating device 1d.
[0135] A power generating operation of the electrostatic induction
power generating device 1d according to the seventh embodiment of
the present invention will be now described with reference to FIGS.
11 and 14.
[0136] When no vibration is applied to the electrostatic induction
power generating device 1d, the electret film 13 and the movable
electrode 24 are arranged to be opposed to each other at a
prescribed interval, as shown in FIG. 11. At this time, positive
electric charges or negative electric charges are stored in the
surface of the electret film 13. Charges opposite to the electric
charges stored in the electret film 13 on a side of the movable
electrode 24 are induced in the movable electrode 24 by
electrostatic induction.
[0137] Then, the movable electrode 24 moves to a position opposed
to the stopper film 14 shown in FIG. 14 from a position opposed to
the electret film 13 shown in FIG. 11 by applying horizontal
vibration (in a direction X) to the electrostatic induction power
generating device 1d and moving the movable electrode 24 in the
direction X. The influence of an electric field resulting from
electric charges stored in the electret film 13 on the movable
electrode 24 is smaller at the position opposed to the stopper film
14 shown in FIG. 14 than at the position opposed to the electret
film 13 shown in FIG. 11, and hence the amount of electric charges
stored in the movable electrode 24 is reduced. Thereafter the
movable electrode 24 is returned to a state shown in FIG. 11 by the
spring portions 22, to be opposed to the electret film 13, thereby
increasing the amount of electric charges stored in the movable
electrode 24. Further, the movable electrode 24 moves in a
direction opposite to the direction X shown in FIG. 14 by inertial
force, to be opposed to the stopper film 14, thereby reducing the
amount of electric charges stored in the movable electrode 24.
Thus, the changed amount of electric charges stored in the movable
electrode 24, induced by repeating lateral (horizontal) vibration
is extracted as a alternating current by a wire (not shown)
connected to the fixed electrode 12 and the movable electrode 24,
thereby generating power. While FIG. 14 shows that the operating
range of the movable electrode 24 is movement to the stopper film
14 adjacent to the opposed electret film 13, the movable electrode
24 may be formed to move to the stopper film 14 next to the
adjacent stopper film 14.
[0138] According to the seventh embodiment, as hereinabove
described, the electrostatic induction power generating device 1d
comprises the stopper film 14 inhibiting the movable electrode 24
and the electret film 13 from coming into contact with each other,
whereby the movable electrode 24 can be inhibited from moving in a
direction Z (vertical direction) shown in FIG. 14 by a physical
impact and coming into contact with the electret film 13, and hence
the amount of electric charges stored in the electret film 13 can
be inhibited from change due to contact between the movable
electrode 24 and the electret film 13.
Eighth Embodiment
[0139] Referring to FIG. 15, an electrostatic induction power
generating device 1e where a guard electrode 15 is formed on an
upper surface of a fixed substrate 11 will be described in this
eighth embodiment dissimilarly to the aforementioned seventh
embodiment.
[0140] In this electrostatic induction power generating device 1e
according to the eighth embodiment, the guard electrode 15 made of
Cu, Au or Al having a thickness of about 20 .mu.m and a width of
about 100 .mu.m is formed on the upper surface of the fixed
substrate 11 to be adjacent to the fixed electrode 12 and an
electret film 13 formed on the fixed electrode 12, as shown in FIG.
15. This guard electrode 15 has a function inhibiting components
other than a component in a direction perpendicular to a main
surface of the electret film 13 in an electric field resulting from
electric charges stored in the electret film 13 from generation.
More specifically, existence of the guard electrode 15 inhibits the
electric field resulting from the electric charges stored in the
electret film 13 from reaching around on the stopper film 14, and
hence change in the capacitance of electric charges stored in the
movable electrode 24 in changing a position of the movable
electrode 24 can be increased. This point has already been
confirmed by a simulation, described later, conducted by inventors
of this application. A potential of the guard electrode 15 is
controlled to 0 V. A stopper film 14a having a thickness of about 1
.mu.m is formed to be stacked on an upper surface of the guard
electrode 15. The stopper film 14a is an example of the "member" in
the present invention. A height of an upper surface of the stopper
film 14a is formed to be at least a height enough to suppress
contact between the electret film 13 and the movable electrode 24
by vibration. The remaining structure of the eighth embodiment is
similar to that of the seventh embodiment.
[0141] According to the eighth embodiment, as hereinabove
described, the guard electrode 15 for inhibiting the components
other than the component in the direction perpendicular to the main
surface of the electret film 13 in the electric field resulting
from the electric charges stored in the electret member 13 from
generation is provided to be adjacent to the electret film 13,
whereby the electric field can be inhibited from reaching a
position not opposed to the main surface of the electret film 13
and hence difference in potentials between a position opposed to
the main surface of the electret film 13 and the position not
opposed to the electret film 13 can be increased. Thus, difference
between the amount of electric charges stored in the movable
electrode 24 by electrostatic induction in a case where the movable
electrode 24 is at the position opposed to the electret film 13 and
the amount of electric charges stored in the movable electrode 24
by electrostatic induction in a case where the movable electrode 24
is at the position not opposed to the electret film 13 can be
increased. Consequently, the amount of power generation can be
increased.
[0142] According to the eighth embodiment, as hereinabove
described, the stopper film 14a is so formed as to be stacked on
the surface of the guard electrode 15 on the side of the movable
electrode 24, whereby a planar region on the upper surface of the
fixed substrate 11 for arranging the stopper film 14a and the guard
electrode 15 is reduced as compared with a case where the stopper
film 14a and the guard electrode 15 are arranged on different
planar positions without being stacked with each other, and hence
size in the electrostatic induction power generating device 1e can
be reduced.
[0143] The remaining effects of the eighth embodiment are similar
to those of the aforementioned seventh embodiment.
[0144] The simulation conducted for confirming the effects of the
guard electrode according to the aforementioned eighth embodiment
will be now described with reference to FIGS. 16 and 17. In this
simulation, it was assumed that an electret film having a thickness
of 1 .mu.m and a width of 100 .mu.m and controlled to a potential
of 1000 V was formed on an insulating film (assuming glass) having
a dielectric constant .epsilon. of 4, as shown in FIG. 16. Further,
it was assumed that a guard electrode having a width of about 100
.mu.m was formed to be adjacent to the electret film at an interval
of 10 .mu.m. It was assumed that four types of 1 .mu.m, 10 .mu.m,
20 .mu.m and 40 .mu.m were employed as a thickness of the guard
electrode. A potential of the guard electrode is controlled to 0 V.
It was assumed that air having a dielectric constant .epsilon. of 1
filled up spaces between the insulating film, the electret film and
the guard electrode. Then distribution of potentials on respective
points by electric charges stored in the electret film was obtained
by an electromagnetical field simulation. More specifically,
differences in potentials between points A above the guard
electrodes at the intervals from the guard electrodes and points B
above the electret films at intervals from the electret films in
cases where the thicknesses of the guard electrodes are 1 .mu.m, 10
.mu.m, 20 .mu.m and 40 .mu.m are obtained respectively. Table 1
shows the results of this experiment.
TABLE-US-00001 TABLE 1 Thickness of Difference in Potentials Guard
Electrode between Point A and Point B (.mu.m) (V) 1 310 10 330 20
347 40 372
[0145] It is understood from the aforementioned Table 1 that the
difference in the potentials between the point A and the point B is
increased as the thickness of the guard electrode is increased.
This shows that the components other than the component in the
direction perpendicular to the main surface of the electret film in
the electric field resulting from the electric charges stored in
the electret film is inhibited from generation as the thickness of
the guard electrode is increased, and the electric field is
inhibited from reaching the point A. Consequently, the difference
in the potentials between the point A and the point B is increased.
This is conceivably for the following reason: In other words, the
lines of electric force are expanded also in directions other than
the direction perpendicular to the main surface of the electret
film in a state where no guard electrode is formed as shown in an
upper figure in FIG. 17. In the case where the guard electrode is
formed as to be adjacent to the electret film, however, it is
conceivable that directions of the lines of electric force are
uniformed in a direction opposed to the movable electrode by the
guard electrode as shown in a lower figure in FIG. 17 and hence the
lines of electric force are inhibited from reaching the point A in
FIG. 16. Consequently, the difference in the potentials between the
point A and the point B shown in FIG. 16 is conceivably increased
when the guard electrode is formed.
Ninth Embodiment
[0146] Referring to FIG. 18, an electrostatic induction power
generating device 1f where a fixed electrode 12 and a guard
electrode 15a have the same thickness and are made of the same
material will be described in this ninth embodiment dissimilarly to
the aforementioned eighth embodiment.
[0147] In this electrostatic induction power generating device 1f
according to the ninth embodiment, the guard electrode 15a having
the same thickness of about 1 .mu.m as the fixed electrode 12 is
formed on an upper surface of a fixed substrate 11 to be adjacent
to the fixed electrode 12 having a thickness of about 1 .mu.m and
an electret film 13 formed on the fixed electrode 12 as shown in
FIG. 18. The fixed electrode 12 and the guard electrode 15a are
made of the same material (Al or Au, for example). Thus, the fixed
electrode 12 and the guard electrode 15a can be simultaneously
formed and hence steps of forming the electrostatic induction power
generating device 1b can be reduced. A stopper film 14b having a
thickness of about 20 .mu.m is formed on an upper surface of the
guard electrode 15a. The stopper film 14b is an example of the
"member" in the present invention. A height of an upper surface of
the stopper film 14b is formed to be a height enough to suppress
contact between the electret film 13 and the movable electrode 24
by vibration. A potential of the guard electrode is controlled to 0
V. The remaining structure is similar to that of the seventh
embodiment.
[0148] The effects of the ninth embodiment are similar to those of
the aforementioned seventh and eighth embodiments.
Tenth Embodiment
[0149] Referring to FIG. 19, an electrostatic induction power
generating device 1g where ends of a surface of a stopper film 14c
on a side of a movable electrode 24 are chamfered will be described
in this tenth embodiment dissimilarly to the aforementioned eighth
embodiment.
[0150] In this electrostatic induction power generating device 1g
according to the tenth embodiment, a guard electrode 15 having a
thickness of about 20 .mu.m is formed on an upper surface of a
fixed substrate 11 as shown in FIG. 10. The stopper film 14c having
a thickness of about 1 .mu.m is formed on an upper surface of the
guard electrode 15. The stopper film 14c is an example of the
"member" in the present invention. At this time, the ends of the
surface of the stopper film 14c on the side of the movable
electrode 24 are chamfered according to the tenth embodiment. A
height of an upper surface of the stopper film 14c is formed to be
a height enough to suppress contact between an electret film 13 and
the movable electrode 24 by vibration. The remaining structure is
similar to that of the seventh embodiment.
[0151] According to the tenth embodiment, as hereinabove described,
the ends of the surface of the stopper film 14c on the side of the
movable electrode 24 are chamfered, whereby the ends of the surface
of the stopper film 14c on the side of the movable electrode 24
have smooth shapes and hence the stopper film 14c and the movable
electrode 24 can be inhibited from coming into contact with and
catching each other when the movable electrode 24 is moving by
vibration.
[0152] The effects of the tenth embodiment are similar to those of
the aforementioned seventh and eighth embodiments.
Eleventh Embodiment
[0153] Referring to FIG. 20, an electrostatic induction power
generating device 1h where a movable electrode 24a is so formed as
to be embedded in a movable substrate 21a will be described in this
eleventh embodiment dissimilarly to the aforementioned tenth
embodiment.
[0154] In this electrostatic induction power generating device 1h
according to the eleventh embodiment, the movable electrode 24a is
so formed as to be embedded in the movable substrate 21a as shown
in FIG. 20. The movable substrate 21a is an example of the "first
substrate" in the present invention. The movable electrode 24a is
an example of the "first electrode" in the present invention.
Thicknesses of the stopper film 14c and the guard electrode 15 are
so formed that the total thickness of the stacked stopper film 14c
and guard electrode 15 is larger than the total thickness of the
stacked fixed electrode 12 and electret film 13. The remaining
structure is similar to that of the tenth embodiment.
[0155] According to the eleventh embodiment, as hereinabove
described, the movable electrode 24a is so formed as to be embedded
in the movable substrate 21a, whereby the surface of the movable
substrate 21a has no irregularities and hence the movable electrode
24a can be inhibited from coming into contact with and catching the
stopper film 14c when the movable electrode 24a is moving by
vibration.
[0156] The effects of the eleventh embodiment are similar to those
of the aforementioned seventh and eighth embodiments.
Twelfth Embodiment
[0157] Referring to FIG. 21, an electrostatic induction power
generating device 1i where a movable substrate 21b vibrates in a
direction Z will be described in this twelfth embodiment
dissimilarly to the aforementioned seventh to eleventh
embodiments.
[0158] In this electrostatic induction power generating device 1i
according to the twelfth embodiment, a spring portion 22a is formed
on an upper surface of the movable substrate 21b as shown in FIG.
21, and the movable substrate 21b moves in the direction Z to
generate power. While an opposed area of the movable electrodes 24
and 24a and the electret film 13 is changed to generate power in
the aforementioned seventh to eleventh embodiments, a distance
between the movable electrode 24 and the electret film 13 is
changed to generate power in the twelfth embodiment. The remaining
structure is similar to that of the seventh embodiment.
[0159] The effects of the twelfth embodiment are similar to those
of the aforementioned seventh embodiment.
Thirteenth Embodiment
[0160] Referring to FIGS. 22 to 24, an electrostatic induction
power generating device 1j where an electret film 43 is so formed
as to be embedded in bottom surfaces of recess portions 421 will be
described in this thirteenth embodiment dissimilarly to the
aforementioned first to twelfth embodiments.
[0161] This electrostatic induction power generating device 1j
according to the thirteenth embodiment is constituted by a fixed
electrode portion 2d, a movable electrode portion 3b and a circuit
71 connected to the fixed electrode portion 2d and the movable
electrode portion 3b, as shown in FIG. 22. A detailed description
will be made hereinafter.
[0162] As shown in FIG. 22, according to the thirteenth embodiment,
a stopper film 42 made of a silicon nitride film is formed on a
surface of a fixed electrode 41 made of silicon in the fixed
electrode portion 2d. The fixed electrode 41 is an example of the
"second electrode" in the present invention. The stopper film 42 is
an example of the "member" in the present invention. The stopper
film 42 is convexly formed on the surface of the fixed electrode
41. The stopper film 42 is an example of the "projecting portion"
in the present invention. As shown in FIG. 23, the stopper film 42
has oblong through holes in plan view. These through holes and the
surface of the fixed electrode 41 form the groove-shaped recess
portions 421. The recess portions 421 have widths W4 of about 10
.mu.m to about 1000 .mu.m and depths D1 of about 0.1 .mu.m to about
100 .mu.m. According to the thirteenth embodiment, the interdigital
electret film 43, made of an organic material such as
polytetrafluoroethylene (PTFE) or a silicon oxide film, having a
thickness of about 0.1 .mu.m to about 50 .mu.m is so formed as to
be embedded in the bottom surfaces (surfaces, formed with no
stopper film 42, of the fixed electrode 41) of the groove-shaped
recess portions 421. The stopper film 42 and the electret film 43
cover a surface, opposed to a movable electrode 62 described later,
of the fixed electrode 41, and hence when charges are injected from
a side of the surface, opposed to the movable electrode 62, of the
fixed electrode 41 by corona discharge, the charges to be injected
can be inhibited from flowing out through the fixed electrode 41
grounded (not shown). Consequently, dispersion of a surface
potential of the electret film 43 can be suppressed.
[0163] As shown in FIG. 22, the movable electrode portion 3b is
arranged at a interval from the fixed electrode portion 2d. In the
movable electrode portion 3b, a movable electrode 62 made of
aluminum, titanium or the like is formed on a surface of a movable
substrate 61 made of quartz. The movable electrode 62 is an example
of the "first electrode" in the present invention. The movable
electrode 62 is interdigitally formed as shown in FIG. 24.
[0164] As shown in FIG. 22, the fixed electrode 41 and the movable
electrode 62 are electrically connected to the circuit 71 through
wires 72.
[0165] A power generating operation of the electrostatic induction
power generating device 1j according to the thirteenth embodiment
of the present invention will be now described with reference to
FIG. 22.
[0166] When no vibration is applied to the electrostatic induction
power generating device 1j, the stopper film 42 and the movable
electrode 62 are arranged to be opposed to each other at a
prescribed interval, as shown in FIG. 22. Then, vibration is
applied to the electrostatic induction power generating device 1j
in a first direction of a horizontal direction (direction X), so
that the electret film 43 and the movable electrode 62 are arranged
to be opposed to each other at a prescribed interval. At this time,
positive charges or negative charges are stored in the surface of
the electret film 43, and charges opposite to the charges stored in
the electret film 43 on a side of the movable electrode 62 are
induced in the movable electrode 62 by electrostatic induction.
[0167] Then, the electrostatic induction power generating device 1j
moves in a second direction of the direction X, so that the stopper
film 42 and the movable electrode 62 are opposed to each other as
shown in FIG. 22. Thus, the amount of electric charges induced in
the movable electrode 62 is changed. This changed amount of the
electric charges is extracted by the circuit 71 connected to the
fixed electrode 41 and the movable electrode 62 thought the wires
72, thereby generating power.
[0168] According to the thirteenth embodiment, as hereinabove
described, the electrostatic induction power generating device 1j
comprises the stopper film 42 and the groove-shaped recess portions
421 provided on the surface of the fixed electrode 41, and the
electret film 43 is so formed as to be embedded in the bottom
surfaces of the recess portions 421, whereby the stopper film 42
can inhibit the movable electrode 62 from moving in the direction Z
(vertical direction) shown in FIG. 22 by a physical impact and
coming into contact with the electret film 43, and hence the amount
of electric charges stored in the electret film 43 can be inhibited
from change due to contact between the movable electrode 62 and the
electret film 43.
Fourteenth Embodiment
[0169] Referring to FIG. 25, a fixed electrode portion 2e formed
with a conductive layer 44 on a surface of a stopper film 42 will
be described in this fourteenth embodiment dissimilarly to the
aforementioned thirteenth embodiment.
[0170] In this fixed electrode portion 2e according to the
fourteenth embodiment, the conductive layer 44 is formed on the
surface of the stopper film 42, as shown in FIG. 25. The remaining
structure of the fourteenth embodiment is similar to that of the
aforementioned thirteenth embodiment.
[0171] According to the fourteenth embodiment, as hereinabove
described, the conductive layer 44 is formed on the surface of the
stopper film 42, whereby components other than a component in a
direction perpendicular to a main surface of an electret film 43 in
an electric field resulting from electric charges stored in the
electret film 43 can be inhibited from generation, and hence the
electric field can be inhibited from reaching a position not
opposed to the main surface of the electret film 43. Thus,
difference in potentials between a position opposed to the main
surface of the electret film 43 and the position not opposed to the
electret film 43 can be increased, and hence difference between the
amount of electric charges induced in an movable electrode 62 (see
FIG. 22) by electrostatic induction in a case where the movable
electrode 62 is at the position opposed to the electret film 43 and
the amount of electric charges induced in the movable electrode 62
by electrostatic induction in a case where the movable electrode 62
is at the position not opposed to the electret film 43 can be
increased. Consequently, the amount of power generation can be
increased.
Fifteenth Embodiment
[0172] Referring to FIG. 26, a fixed electrode portion 2f formed
with groove shaped recess portions 411a and a projecting portion
412a on a surface of a fixed electrode 41a will be described in
this fifteenth embodiment dissimilarly to the aforementioned
thirteenth embodiment.
[0173] In this fixed electrode portion 2f according to the
fifteenth embodiment, the groove shaped recess portions 411a and
the projecting portion 412a are formed on the surface of the fixed
electrode 41a, as shown in FIG. 26. The fixed electrode 41a is an
example of the "second electrode" in the present invention. Each of
the recess portions 411a has a width W4 of about 10 .mu.m to about
1000 .mu.m and a depth D1 of about 0.1 .mu.m to about 100 .mu.m.
Similarly to the seventh embodiment shown in FIG. 23, the groove
shaped recess portions 411a are oblongly formed in plan view.
According to the fifteenth embodiment, electret films 43 made of an
organic material such as PTFE or a silicon oxide film, having a
thickness of about 0.1 .mu.m to about 50 .mu.m smaller than the
depth D1 of each recess portion 411a is so formed as to fill up a
bottom surface of the groove shaped recess portion 411a.
[0174] The remaining structure of the fifteenth embodiment is
similar to that of the aforementioned thirteenth embodiment.
[0175] According to the fifteenth embodiment, as hereinabove
described, the groove shaped recess portions 411a and the
projecting portion 412a provided on the surface of the fixed
electrode 41a are provided and the electret films 43a are so formed
as to be embedded in the bottom surfaces of the recess portions
411a, whereby the projecting portion 412a can inhibit a movable
electrode 62 from moving in a direction Z (vertical direction)
shown in FIG. 22 by a physical impact and coming into contact with
the electret films 43a, and hence the amount of electric charges
stored in the electret films 43a can be inhibited from change due
to contact between the movable electrode 62 and the electret films
43a. Further, the electret films 43a are so formed as to be
embedded in the bottom surfaces of the recess portions 411a
provided on the surface of the fixed electrode 41a, whereby the
electret films 43a are not separated by cleavage in a case where a
plurality of the electret films 43a are formed on the fixed
electrode 41a and the fixed electrode 41a is separated into
individual fixed electrodes 41a by cleavage, dissimilarly to a case
where the electret film 43a is formed on an overall surface of the
fixed electrode 41a, and hence charges can be inhibited from
flowing out of cleavage surfaces of the electret films 43a. Thus,
reduction in surface potentials of the electret films 43a can be
suppressed.
Sixteenth Embodiment
[0176] Referring to FIG. 27, a fixed electrode portion 2g where
electret films 43b are formed also on side surfaces of groove
shaped recess portions 411a will be described in this sixteenth
embodiment dissimilarly to the aforementioned fifteenth
embodiment.
[0177] In the fixed electrode portion 2g according to the sixteenth
embodiment, the electret films 43b made of an organic material such
as PTFE or a silicon oxide film are so formed as to be embedded in
bottom surfaces of the groove shaped recess portions 411a and also
in the side surfaces of the groove shaped recess portions 411a as
shown in FIG. 27. Thus, the electret films 43b are formed on the
side surfaces of the groove shaped recess portions 411a and a large
number of electric charges can be stored, and hence the amount of
electric charges stored in the electret films 43b can be increased.
Consequently, the amount of power generation can be increased.
[0178] The remaining structure of the sixteenth embodiment is
similar to that of the aforementioned fifteenth embodiment.
Seventeenth Embodiment
[0179] Referring to FIG. 28, a fixed electrode portion 2h where a
stopper film 45a is formed on a surface of a projecting portion
412a will be described in this seventeenth embodiment dissimilarly
to the aforementioned sixteenth embodiment.
[0180] In this fixed electrode portion 2h according to the
seventeenth embodiment, the stopper film 45a made of an insulating
film having a breakdown voltage smaller than electret films 43b is
formed on the surface of the projecting portion 412a, as shown in
FIG. 28. The stopper films 45a are examples of the "member" in the
present invention. While the electret films 45b shown in FIG. 28
are formed on inner sides of groove shaped recess portions 411a,
the ends of the electret films 45b may be formed as to be embedded
between the stopper film 45a and the projecting portion 412a. At
this time, the ends of the stopper film 45a is formed in upwardly
warped shapes.
[0181] The remaining structure of the seventeenth embodiment are
similar to that of the aforementioned sixteenth embodiment.
[0182] According to the seventeenth embodiment, as hereinabove
described, the stopper film 45a having the breakdown voltage
smaller than the electret films 43b is formed on the surface of the
projecting portion 412a, whereby even when the electret films 43b
and the stopper film 45a are simultaneously made electret, the
stopper film 45a first causes dielectric breakdown due to the
smaller breakdown voltage of the stopper film 45a than the electret
films 43b, and hence the electret films 43b can store a larger
number of electric charges and the amounts of electric charges
stored in the electret films 43b and the stopper film 45a are made
different from each other. Thus, an intensity of an electric field
on the surface of each electret film 43b and an intensity of an
electric field on the surface of the stopper film 45a can be made
different. The stopper film 45a is formed on the surface of the
projecting portion 412a, whereby the movable electrode 62 (see FIG.
22) and the electret films 43b can be easily inhibited from coming
into contact with each other.
Eighteenth Embodiment
[0183] Referring to FIG. 29, a fixed electrode portion 2i formed
with a charge outflow inhibition film 46 on a surface thereof will
be described in this eighteenth embodiment dissimilarly to the
aforementioned seventeenth embodiment.
[0184] In this fixed electrode portion 2i according to the
eighteenth embodiment, the charge outflow inhibition film 46 made
of MSQ (methyl silses quioxane) is formed on the surface of the
fixed electrode portion 2i as shown in FIG. 29. Thus, electric
charges can be inhibited from flowing out of electret films 43b.
The electret films 43b are formed on bottom surfaces and side
surfaces of recess portions 411a and central portions of the
electret films 43b are concave. The charge outflow inhibition film
46 formed on the central portions of the electret films 43b is also
concave similarly to this. Thus, the charge outflow inhibition film
46 formed on the central portions of the electret films 43b can be
inhibited from deterioration even when the charge outflow
inhibition film 46 formed on the stopper film 45a is deteriorated
by abrasion or the like. Consequently, the life of the electret
films 43b can be increased.
[0185] The remaining structure of the eighteenth embodiment is
similar to that of the aforementioned seventeenth embodiment.
Nineteenth Embodiment
[0186] Referring to FIG. 30, a fixed electrode portion 2j where
electret films 43c are formed also on side surfaces of a stopper
film 45a will be described in this nineteenth embodiment
dissimilarly to the aforementioned seventeenth embodiment.
[0187] In the fixed electrode portion 2j according to the
nineteenth embodiment, the electret films 43c made of an organic
material such as PTFE or a silicon oxide film are so formed as to
be embedded in bottom surfaces of groove shaped recess portions
411a and also in side surfaces of the groove shaped recess portions
411a and the side surfaces of the stopper film 45a as shown in FIG.
30. The electret films 43c are formed also on the side surfaces of
the stopper film 45a and electric charges stored in the electret
films 43c can be increased.
[0188] The remaining structure of the nineteenth embodiment is
similar to that of the aforementioned seventeenth embodiment.
Twentieth Embodiment
[0189] Referring to FIG. 31, a fixed electrode portion 2k where
electret films 43d are so formed as to be embedded in recess
portions 411a will be described in this twentieth embodiment
dissimilarly to the aforementioned nineteenth embodiment.
[0190] In this fixed electrode portion 2k according to the
twentieth embodiment, the electret films 43d made of an organic
material such as PTFE or a silicon oxide film are so formed as to
be embedded in recess portions 411a as shown in FIG. 31.
[0191] The remaining structure of the twentieth embodiment is
similar to that of the aforementioned seventeenth embodiment.
[0192] The effects of the twentieth embodiment are similar to those
of the aforementioned seventeenth embodiment.
Twenty-First Embodiment
[0193] Referring to FIG. 32, a fixed electrode portion 21 where
recess portions 411b are so formed that widths thereof are
increased from bottom surfaces of the recess portions 411b toward
open upper ends thereof will be described in this twenty-first
embodiment dissimilarly to the aforementioned fifteenth to
twentieth embodiments.
[0194] In the fixed electrode portion 21 according to the
twenty-first embodiment, the groove shaped recess portions 411b and
a projecting portion 412b are formed on a surface of a fixed
electrode 41b as shown in FIG. 32. The fixed electrode 41b is an
example of the "second electrode" in the present invention. The
projecting portion 412b is an example of the "member" in the
present invention. The recess portions 411b have widths W5 of about
10 .mu.m to about 1000 .mu.m and depths D3 of about 0.1 .mu.m to
about 100 .mu.m. According to the twenty-first embodiment, the
recess portions 411b are so formed that the widths thereof are
increased from the bottom surfaces of the recess portions 411b
toward the open upper ends thereof. The groove shaped recess
portions 411b are oblongly formed in plan view similarly to the
thirteenth embodiment shown in FIG. 23. In the groove shaped recess
portions 411b, electret films 43e made of an organic material such
as PTFE of a silicon oxide film are formed on bottom surfaces of
the recess portions 411b with thicknesses D4 of about 0.1 .mu.m to
about 50 .mu.m smaller than depths D3 of the recess portions
411b.
[0195] The remaining structure of the twenty-first embodiment is
similar to that of the aforementioned thirteenth embodiment.
[0196] According to the twenty-first embodiment, as hereinabove
described, the recess portions 411b are so formed that the widths
thereof are increased from the bottom surfaces of the recess
portions 411b toward the open upper ends thereof, whereby the
thicknesses of the electret films 43e in the vicinity of the side
surfaces of the recess portions 411b are reduced, and hence
electric fields in the vicinity of the side surfaces of the recess
portions 411b become weak. Thus, discharge from the electret films
43e can be suppressed, when a movable electrode 62 (see FIG. 22)
comes close. The electric fields in the vicinity of the side
surfaces of the recess portions 411b are weak, and hence injection
of electric charges in the bottom surfaces of the electret films
43e can be inhibited from becoming difficult due to repulsion force
of the electric fields in the vicinity of the side surfaces of the
recess portions 411b when electric charges are injected in the
electret films 43e by corona discharge. Further, the recess
portions 411b are so formed that the widths thereof are increased
from the bottom surfaces of the recess portions 411b toward the
open upper ends thereof, whereby the side surfaces of the recess
portions 411b are inclined and hence the movable electrode 62 (see
FIG. 22) can be inhibited from catching the side surfaces of the
recess portions 411b.
Twenty-Second Embodiment
[0197] Referring to FIG. 33, a fixed electrode portion 2m where a
stopper film 45b is formed on a surface of a projecting portion
412b will be described in this twenty-second embodiment
dissimilarly to the aforementioned twenty-first embodiment.
[0198] In this fixed electrode portion 2m according to the
twenty-second embodiment, the stopper film 45b made of an
insulating film, having a breakdown voltage smaller than electret
films 43e is formed on the surface of the projecting portion 412b,
as shown in FIG. 33. The stopper film 45b is an example of the
"member" in the present invention. The stopper film 45b is formed
on the surface of the projecting portion 412b, whereby contact
between a movable electrode 62 (see FIG. 22) and the electret films
43e can be easily suppressed.
[0199] The remaining structure of the twenty-second embodiment is
similar to that of the aforementioned twenty-first embodiment.
Twenty-Third Embodiment
[0200] Referring to FIG. 34, a fixed electrode portion 2n where
electret films 43f are formed also on side surfaces of groove
shaped recess portions 411b will be described in this twenty-third
embodiment dissimilarly to the aforementioned twenty-first
embodiment.
[0201] In this fixed electrode portion 2n according to the
twenty-third embodiment, the electret films 43f made of an organic
material such as PTFE or a silicon oxide film are so formed as to
be embedded in bottom surfaces of the groove shaped recess portions
411b and also in the side surfaces of the groove shaped recess
portions 411b as shown in FIG. 34. Thus, the electret films 43f are
formed also on the side surfaces of the groove shaped recess
portions 411b and can store a larger amounts of electric charges,
and hence the amount of electric charges stored in the electret
films 43f can be increased. Consequently, the amount of power
generation can be increased.
[0202] The remaining structure of the twenty-third embodiment is
similar to that of the aforementioned twenty-first embodiment.
[0203] The effects of the twenty-third embodiment are similar to
those of the aforementioned twenty-first embodiment.
Twenty-Fourth Embodiment
[0204] Referring to FIG. 35, a fixed electrode portion 2o where a
stopper film 45b is formed on a surface of a projecting portion
412b will be described in this twenty-fourth embodiment
dissimilarly to the aforementioned twenty-third embodiment.
[0205] In this fixed electrode portion 2o according to the
twenty-fourth embodiment, the stopper film 45b made of an
insulating film having a breakdown voltage smaller than electret
films 43f is formed on the surface of the projecting portion 412b,
as shown in FIG. 35. The stopper films 45b are examples of the
"member" in the present invention.
[0206] The remaining structure of the twenty-fourth embodiment is
similar to that of the aforementioned twenty- third embodiment.
[0207] According to the twenty-fourth embodiment, as hereinabove
described, the stopper film 45b having the breakdown voltage
smaller than the electret films 43f is formed on the surface of the
projecting portion 412b, whereby even when the electret films 43f
and the stopper film 45b are simultaneously made electret, the
stopper film 45b first causes dielectric breakdown due to the
smaller breakdown voltage of the stopper film 45b than the electret
films 43f, and hence the amounts of electric charges stored in the
electret films 43f and the stopper film 45b can be made different
from each other. Thus, an intensity of an electric field on the
surface of each electret film 43f and an intensity of an electric
field on the surface of the stopper film 45b can be made
different.
Twenty-Fifth Embodiment
[0208] Referring to FIG. 36, a fixed electrode portion 2p where a
projecting portion 413c is formed on ends of a fixed electrode 41c
will be described in this twenty-fifth embodiment dissimilarly to
the aforementioned fifteenth to twenty-fourth embodiments.
[0209] In this fixed electrode portion 2p according to the
twenty-fifth embodiment, groove shaped recess portions 411c and a
projecting portion 412c are formed on a surface of the fixed
electrode 41c made of silicon as shown in FIG. 36. The fixed
electrode 41c is an example of the "second electrode" in the
present invention. Similarly to the thirteenth embodiment shown in
FIG. 23, the groove shaped recess portions 411c are oblongly formed
in plan view. According to the twenty-fifth embodiment, the
projecting portion 413c for inhibiting a movable electrode 62 (see
FIG. 22) and electret films 43g, described later, from coming into
contact with each other is formed on the ends of the fixed
electrode portion 2p. The projecting portion 413c is an example of
the "member" in the present invention. The electret films 43g made
of an organic material such as PTFE or a silicon oxide film are so
formed as to be embedded in bottom surfaces of the groove shaped
recess portions 411c and cover the side surfaces of the recess
portions 411c.
[0210] The remaining structure of the twenty-fifth embodiment is
similar to that of the aforementioned thirteenth embodiment.
[0211] According to the twenty-fifth embodiment, as hereinabove
described, the projecting portion 413c for inhibiting the movable
electrode 62 and the electret films 43g from coming into contact
with each other is provided, whereby the movable electrode 62 can
be inhibited from moving in a direction Z (vertical direction)
shown in FIG. 22 by a physical impact and coming into contact with
the electret films 43g, and hence the amount of electric charges
stored in the electret films 43g can be inhibited from change due
to contact between the movable electrode 62 and the electret films
43g.
Twenty-Sixth Embodiment
[0212] Referring to FIG. 37, a fixed electrode portion 2q where a
charge outflow inhibition film 48 is formed on surfaces of an
electret film 43i and conductive layers 47 will be described in
this twenty-sixth embodiment dissimilarly to the aforementioned
twenty-fifth embodiment.
[0213] In this fixed electrode portion 2q according to this
twenty-sixth embodiment, a groove shaped recess portion 411e and a
projecting portion 412e are formed on a surface of a fixed
electrode 41e made of silicon, quartz, plastic or Teflon
(registered trademark) as shown in FIG. 37. The fixed electrode 41e
made of silicon is an example of the "second electrode" in the
present invention. The groove shaped recess portion 411e is
rectangularly formed in plan view. The projecting portion 412e has
a function of inhibiting a movable electrode 62 (see FIG. 22) and
the electret film 43i, described later, from coming into contact
with each other. The projecting portion 412e is an example of the
"member" in the present invention. The electret film 43i made of an
organic material such as PTFE or a silicon oxide film, having a
thickness of about 0.1 .mu.m to about 50 .mu.m is so formed as to
be embedded in bottom surface of the groove shaped recess portion
411e. Projecting portions 431i are formed on a surface of the
electret film 43i on a side opposed to the movable electrode 62
(see FIG. 22). The conductive layers 47 are formed on surfaces of
the projecting portions 431i. The charge outflow inhibition film 48
made of MSQ is formed on the surfaces of the projecting portions
431i and the conductive layers 47. Thus, electric charges can be
inhibited from flowing out of the surface of the electret film
43i.
[0214] The remaining structure of the twenty-sixth embodiment is
similar to that of the aforementioned thirteenth embodiment.
Twenty-Seventh Embodiment
[0215] Referring to FIG. 38, an electrostatic induction power
generating device 1k where stopper films 93 are arranged between a
movable substrate 92 and a fixed electrode 90 will be described in
this twenty-seventh embodiment dissimilarly to the aforementioned
first to twenty-sixth embodiments.
[0216] In this electrostatic induction power generating device 1k
according to the twenty-seventh embodiment, electret films 91 are
formed on a surface of the fixed electrode 90 made of silicon as
shown in FIG. 38. Movable electrodes 93 are so formed on a surface
of the movable substrate 92 arranged to be opposed to the fixed
electrode 90 as to be opposed to the electret films 91. The movable
electrodes 93 is an example of the "first electrode" in the present
invention. The fixed electrode 90 is an example of the "second
electrode" in the present invention. The stopper films 94a re
arranged between the fixed electrode 90 and the movable substrate
92 at intervals from the fixed electrode 90 and the movable
substrate 92. Thus, the movable electrodes 93 and the electret
films 91 can be inhibited from coming into contact with each other.
The stopper films 94 are examples of the "member" in the present
invention.
[0217] In the electrostatic induction power generating device 1k,
the movable substrate 92 and the fixed electrode 90 relatively move
in a direction X, whereby the amount of electric charges stored in
the movable electrodes 93 are changed by electrostatic induction
resulting from electric charges stored in the electret films 91,
and hence power can be generated by extracting this changed amount
of the electric charges.
Twenty-Eighth Embodiment
[0218] Referring to FIGS. 39 and 40, an electrostatic induction
power generating device 1l where stopper films 94a are arranged on
a housing 95 will be described in this twenty-eighth embodiment
dissimilarly to the aforementioned twenty-seventh embodiment.
[0219] In this electrostatic induction power generating device 1l
according to the twenty-eighth embodiment, a movable substrate 92
is formed on a lower surface of inner surfaces of the housing 95,
as shown in FIG. 39. Movable electrodes 93 are formed on a lower
surface of the movable substrate 92. The movable electrodes 93 are
examples of the "first electrode" in the present invention. The
movable electrodes 93 are interdigitally formed. The fixed
electrode 90 made of silicon is arranged at an interval from the
movable substrate 92. The fixed electrode 90 is an example of the
"second electrode" in the present invention. As shown in FIG. 40,
the electret films 91 are formed on an upper surface of the fixed
electrode 90 on a side of the movable electrodes 93 and are
oblongly formed similarly to the movable electrodes 93.
[0220] As shown in FIG. 39, the stopper films 94a are arranged on
side surfaces of the inner surfaces of the housing 95 between the
fixed electrode 90 and the movable substrate 92 at intervals from
the fixed electrode 90 and the movable substrate 92. The stopper
films 94a are examples of the "member" in the present invention.
The stopper films 94a are formed in a direction parallel to an
extensional direction of the oblong movable electrodes 93.
[0221] In the electrostatic induction power generating device 1l,
the movable substrate 92 (housing 95) and the fixed electrode 90
relatively move in a direction X, whereby the amount of electric
charges stored in the movable electrodes 93 are changed by
electrostatic induction resulting from electric charges stored in
the electret films 91, and hence power can be generated by
extracting this changed amount of the electric charges.
Twenty-Ninth Embodiment
[0222] Referring to FIG. 41, an electrostatic induction power
generating device 1m where a fixed electrode 90 is fixed to a
housing 95 will be described in this twenty-ninth embodiment
dissimilarly to the aforementioned twenty-eighth embodiment.
[0223] In this electrostatic induction power generating device 1m
according to the twenty-ninth embodiment, the fixed electrode 90 is
formed on an upper surface of an inner surface of the housing 95 as
shown in FIG. 41. A movable substrate 92 is not fixed to the
housing 95 dissimilarly to the twenty-eighth embodiment. The
remaining structure of the twenty-ninth embodiment is similar to
that of the aforementioned twenty-eighth embodiment.
Thirtieth Embodiment
[0224] Referring to FIG. 42, an electrostatic induction power
generating device 1n where stopper films 94a are in contact with a
fixed electrode 90 and a movable substrate 92 will be described in
this thirtieth embodiment dissimilarly to the aforementioned
twenty-ninth embodiment.
[0225] In this electrostatic induction power generating device 1n
according to the thirtieth embodiment, the stopper films 94a are
arranged in contact with the fixed electrode 90 and the movable
substrate 92 as shown in FIG. 42.
Thirty-First Embodiment
[0226] Referring to FIGS. 43 to 45, an electrostatic induction
power generating device 1o where stopper films 94a and a stopper
film 94b are arranged on side surfaces and a central portion of
inner surfaces of a housing 95 respectively will be described in
this thirty-first embodiment dissimilarly to the aforementioned
thirtieth embodiment.
[0227] In this electrostatic induction power generating device
1o
[0228] according to the thirty-first embodiment, the stopper films
94a are arranged on the side surfaces of the inner surfaces of the
housing 95 and the stopper film 94b is arranged on the central
portion of the inner surfaces of the housing 95, as shown in FIGS.
43 to 45. Thus, the electret films 91 and the movable electrodes 93
can be inhibited from coming into contact with each other at the
central portion even when the movable substrate 92 and the fixed
electrode 90 are warped. The stopper film 94b is an example of the
"member" in the present invention. The electret films 91 are
oblongly formed and the stopper films 94a and 94b are so formed as
to extend in a direction Y intersecting with an extensional
direction (direction X) of the oblong electret films 91. In the
electrostatic induction power generating device 1o, the movable
substrate 92 and the fixed electrode 90 relatively move in the
direction Y, thereby generating power.
Thirty-Second Embodiment
[0229] Referring to FIGS. 46 and 47, an electrostatic induction
power generating device 1p where stopper films 94a are arranged
only on side surfaces of inner surfaces of a housing 95 will be
described in this thirty-second embodiment dissimilarly to the
aforementioned thirty-first embodiment.
[0230] In this electrostatic induction power generating device 1p
according to the thirty-second embodiment, the stopper films 94a
are arranged on the side surfaces of the inner surfaces of the
housing 95 as shown in FIGS. 46 and 47 and not arranged on a
central portion of the housing 95 dissimilarly to the
aforementioned thirty-first embodiment. The remaining structure of
the thirty-second embodiment is similar to that of the
aforementioned thirty-first embodiment.
Thirty-Third Embodiment
[0231] Referring to FIGS. 48 and 49, an electrostatic induction
power generating device 1q where stopper film 94b is arranged only
on a central portion of inner surfaces of a housing 95 will be
described in this thirty-third embodiment dissimilarly to the
aforementioned thirty-first embodiment.
[0232] In this electrostatic induction power generating device 1q
according to the thirty-third embodiment, the stopper film 94b is
arranged on the central portion of the inner surfaces of the
housing 95 as shown in FIGS. 48 and 49 and not arranged on the side
surfaces of the housing 95 dissimilarly to the aforementioned
thirty-first embodiment. The remaining structure of the
thirty-third embodiment is similar to that of the aforementioned
thirty-first embodiment.
Thirty-Fourth Embodiment
[0233] Referring to FIG. 50, an electrostatic induction power
generating device 1r where stopper films 96a are formed on a lower
surface of a movable electrode 92 will be described in this
thirty-fourth embodiment dissimilarly to the aforementioned
thirteenth embodiment.
[0234] In this electrostatic induction power generating device 1r
according to the thirty-fourth embodiment, movable electrodes 93
are formed on the lower surface of the movable electrode 92 and the
stopper films 96a are arranged on ends of the movable substrate 92
to be adjacent to the movable electrodes 93, as shown in FIG. 50.
The stopper films 96a are examples of the "member" in the present
invention. A fixed electrode portion 2f is provided to be opposed
to the movable substrate 92. The structure of the fixed electrode
portion 2f is similar to that of the aforementioned fifteenth
embodiment shown in FIG. 26.
[0235] In this electrostatic induction power generating device 1r,
the projecting portion 412a protruding beyond surfaces of electret
films 43a is provided on the fixed electrode portion 2b and the
stopper films 96a are arranged on the lower surface of the movable
substrate 92, whereby the movable electrode 92 and the electret
films 43a can be further inhibited from coming into contact with
each other.
Thirty-Fifth Embodiment
[0236] Referring to FIG. 51, an electrostatic induction power
generating device 1s where stopper films 96b are arranged between a
movable substrate 92 and a fixed electrode portion 2f will be
described in this thirty-fifth embodiment dissimilarly to the
aforementioned thirty-fourth embodiment.
[0237] In this electrostatic induction power generating device 1s
according to the thirty-fifth embodiment, the stopper films 96b are
arranged between the movable substrate 92 and the fixed electrode
portion 2f at intervals from the movable substrate 92 and the fixed
electrode portion 2f, as shown in FIG. 51. The stopper films 96b
are examples of the "member" in the present invention. The stopper
films 96b are arranged at positions opposed to ends of the movable
substrate 92 and the fixed electrode portion 2f. The remaining
structure of the thirty-fifth embodiment is similar to that of the
aforementioned thirty-fourth embodiment.
Thirty-Sixth Embodiment
[0238] Referring to FIG. 52, an electrostatic induction power
generating device 1t where stopper films 96c are arranged on an
upper surface of a fixed electrode portion 2f will be described in
this thirty-sixth embodiment dissimilarly to the aforementioned
thirty-fourth embodiment.
[0239] In this electrostatic induction power generating device 1t
according to the thirty-sixth embodiment, the stopper films 96c are
arranged on the upper surface of ends of the fixed electrode
portion 2f, as shown in FIG. 52. The stopper films 96c are examples
of the "member" in the present invention. The remaining structure
of the thirty-sixth embodiment is similar to that of the
aforementioned thirty-fourth embodiment.
Thirty-Seventh Embodiment
[0240] Referring to FIG. 53, a movable electrode portion 3c where a
protective film 97 covers a surface of a movable electrode portion
3c will be described in this thirty-seventh embodiment dissimilarly
to the aforementioned first to thirty-sixth embodiments.
[0241] In this movable electrode portion 3c according to the
thirty-sixth embodiment, movable electrodes 93 are formed on a
lower surface of a movable substrate 92 as shown in FIG. 53. The
protective film 97 made of an insulating film such as a silicon
oxide film or a silicon nitride film is formed to cover the lower
surface of the movable substrate 92 and surfaces of the movable
electrodes 93.
[0242] According to the thirty-seventh embodiment, as hereinabove
described, the protective film 97 made of the insulating film such
as the silicon oxide film or the silicon nitride film is formed to
cover the lower surface of the movable substrate 92 and the
surfaces of the movable electrodes 93, whereby the protective film
97 can inhibit electret films arranged on positions opposed to the
movable electrodes 93 and the movable electrodes 93 from coming
into contact with each other.
Thirty-Eighth Embodiment
[0243] Referring to FIG. 54, an electrostatic induction power
generating device 1u where a movable electrode 62 and a movable
electrode 62a are provided on a surface of a movable substrate 7 to
be adjacent to each other will be described in this thirty-eighth
embodiment dissimilarly to the aforementioned first to
thirty-seventh embodiments.
[0244] As shown in FIG. 54, this electrostatic induction power
generating device 1u according to the thirty-eighth embodiment is
constituted by a fixed electrode portion 2r and a movable electrode
portion 3e. A detailed description will be made hereinafter.
[0245] In the fixed electrode portion 2r, an electret film 5b made
of a thermal oxide film having projecting portions 501a is formed
on a surface of a fixed electrode 4a made of silicon, as shown in
FIG. 54. Conductive layers 6b are formed on surfaces of the
projecting portions 501a. The conductive layers 6b are
interdigitally or oblongly formed. A charge outflow inhibition film
48a is formed to cover surfaces of the electret film 5b and the
conductive layers 6b. Stoppers 9b are formed on ends of the
electret film 5b. Each of stoppers 9b has a function as a spacer
keeping an interval between the movable electrodes 62 and 62a and
the electret film 5b constant.
[0246] In the movable electrode portion 3e, the movable electrode
62 and the movable electrode 62a are provided to be adjacent to
each other on a surface of the movable substrate 7 made of quartz
as shown in FIG. 54. The movable electrode 62 and the movable
electrode 62a are examples of the "first electrode" and the "second
electrode" in the present invention respectively. A protective film
63 made of a sputtered oxide film or nitride film is formed to
cover surfaces of the movable substrate 7, the movable electrode 62
and the movable electrode 62a. A circuit 71 is electrically
connected to the movable electrode 62 and the movable electrode 62a
through wires 72.
[0247] A power generating operation of the electrostatic induction
power generating device 1u according to the thirty-eighth
embodiment of the present invention will be now described with
reference to FIG. 54.
[0248] When no vibration is applied to the electrostatic induction
power generating device 1u, the projecting portions 501a of the
electret film 5b and the movable electrode 62 are arranged to be
opposed to each other at a prescribed interval, as shown in FIG.
54. At this time, positive electric charges or negative electric
charges are stored in the surface of the electret film 5b. The
conductive layers 6b are formed on the surfaces of the projecting
portions 501a, whereby an electric field on a surface of a recess
portion 501b which is a region formed with no projecting portions
501a on the surface of the electret film 5b is stronger than an
electric field on the surfaces of the projecting portions 501a.
Consequently, electric charges electrostatically induced in the
movable electrode 62a are larger than electric charges
electrostatically induced in the movable electrode 62.
[0249] Then, the movable electrode 62 moves to a position opposed
to the recess portion 501b and the movable electrode 62a moves to
positions opposed to the projecting portions 501a by application of
horizontal vibration (in a direction X) to the electrostatic
induction power generating device 1u and relative movement of the
movable electrode portion 3e and the fixed electrode portion 2r in
the direction X. Thus, electric charges electrostatically induced
in the movable electrodes 62 and 62a are changed. This changed
amount of the electric charges electrostatically induced in the
movable electrodes 62 and 62a is extracted as a current through the
wires 72 by the circuit 71, whereby the electrostatic induction
power generating device 1u can generate power.
[0250] According to the thirty-eighth embodiment, as hereinabove
described, the electrostatic induction power generating device 1u
comprises the stoppers 9b inhibiting the movable electrodes 62 and
62a and the electret film 5b from coming into contact with each
other, whereby the movable electrodes 62 and 62a and the electret
film 5b can be inhibited from coming into contact with each other
due to a physical impact, and hence the amount of electric charges
stored in the electret film 5b can be inhibited from change due to
contact between the movable electrodes 62 and 62a and the electret
film 5b.
Thirty-Ninth Embodiment
[0251] Referring to FIG. 55, an electrostatic induction power
generating device 1v where a projecting portion 401c is formed on
ends of a fixed substrate 4b will be described in this thirty-ninth
embodiment dissimilarly to the aforementioned thirty-eighth
embodiment.
[0252] This electrostatic induction power generating device 1v
according to the thirty-ninth embodiment is constituted by a fixed
electrode portion 2s and a movable electrode portion 3e as shown in
FIG. 55. A detailed description will be made hereinafter.
[0253] In the fixed electrode portion 2s, an electret film 5b is so
formed as to be embedded in a bottom surface of a recess portion
401d of the fixed substrate 4b made of silicon having the
projecting portion 401c and the recess portion 401d, as shown in
FIG. 55. The fixed substrate 4b is an example of the "substrate" in
the present invention. The projecting portion 401c is an example of
the "member" in the present invention. The projecting portion 401c
has a function as a stopper inhibiting the movable electrodes 62
and 62a and the electret film 5b from coming into contact with each
other and also has a function as a spacer keeping an interval
between the movable electrodes 62 and 62a and the electret film 5b
constant.
[0254] The remaining structure of the thirty-ninth embodiment is
similar to that of the aforementioned thirty-eighth embodiment.
[0255] An operation of the thirty-ninth embodiment is similar to
that of the aforementioned thirty-eighth embodiment.
[0256] According to the thirty-ninth embodiment, as hereinabove
described, the projecting portion 401c of the fixed substrate 4b
form a stopper to inhibit the movable electrodes 62 and 62a and the
electret film 5b from coming into contact with each other, whereby
the movable electrodes 62 and 62a and the electret film 5b can be
inhibited from coming into contact with each other due to a
physical impact, and hence the amount of electric charges stored in
the electret film 5b can be inhibited from change due to contact
between the movable electrodes 62 and 62a and the electret film
5b.
Fortieth Embodiment
[0257] Referring to FIG. 56, an electrostatic induction power
generating device 1w where stoppers 9b are formed on a surface of a
protective film 63 will be described in this fortieth embodiment
dissimilarly to the aforementioned thirty-eighth embodiment.
[0258] In this electrostatic induction power generating device 1w
according to the fortieth embodiment, the stoppers 9b are formed on
the surface of the protective film 63 as shown in FIG. 56. The
remaining structure of the fortieth embodiment is similar to that
of the aforementioned thirty-eighth embodiment.
[0259] An operation of the fortieth embodiment is similar to that
of the aforementioned thirty-eighth embodiment.
Forty-First Embodiment
[0260] Referring to FIG. 57, an electrostatic induction power
generating device 1x where insulating films 410 are formed on a
surface of an electret film 5a will be described in this
forty-first embodiment dissimilarly to the aforementioned
thirty-eighth embodiment.
[0261] In a fixed electrode portion 2t of this electrostatic
induction power generating device 1x according to the forty-first
embodiment, the electret film 5a is formed on a surface of a fixed
electrode 4a as shown in FIG. 57. The insulating films 410 are
formed on the surface of the electret film 5a. The insulating films
410 are interdigitally or oblongly formed. Conductive layers 6b are
formed on surfaces of the insulating films 410. A charge outflow
inhibition film 48a is formed to cover surfaces of the electret
film 5a and the conductive layers 6b.
[0262] The remaining structure of the forty-first embodiment is
similar to that of the aforementioned thirty-eighth embodiment.
[0263] An operation of the forty-first embodiment is similar to
that of the aforementioned thirty-eighth embodiment.
[0264] The embodiments disclosed this time must be considered as
illustrative in all points and not restrictive. The range of the
present invention is shown not by the above description of the
embodiments but by the scope of claims for patent, and all
modifications within the meaning and range equivalent to the scope
of claims for patent are included.
[0265] For example, while the example of employing the interdigital
or oblong electret film(s) and movable electrode(s) is shown in
each of the aforementioned first to eleventh embodiments and
thirteenth embodiment to forty-first embodiments, the present
invention is not restricted to this but a movable electrode(s) and
an electret film(s) formed in shapes other than the interdigital
shapes may be employed so far as the movable electrode(s) and the
electret film(s) are formed such that the opposing areas are
changed by vibration.
[0266] While the example of employing the interdigital electret
film and movable electrode is shown in the aforementioned twelfth
embodiment, the present invention is not restricted to this but a
movable electrode(s) and an electret film(s) formed in shapes other
than the interdigital shapes may be employed so far as the movable
electrode(s) and the electret film(s) are opposed to each
other.
[0267] While the example of employing the fixed substrate and the
movable substrate made of glass is shown in each of the
aforementioned seventh to twelfth embodiments, the present
invention is not restricted to this but a fixed substrate and a
movable substrate made of silicon may be employed.
[0268] While the example of employing the column portion made of
silicon is shown in each of the aforementioned seventh to twelfth
embodiments, the present invention is not restricted to this but a
column portion made of polyimide which is an organic polymer
material may be employed.
[0269] While the example of employing the electret film made of
Teflon (registered trademark) is shown in each of the
aforementioned seventh to twelfth embodiments, the present
invention is not restricted to this but an electret film made of PP
(polypropylene), PET (polyethylene terephthalate), PVC (polyvinyl
chloride), PS (polystyrene), PTFE (polytetrafluoroethylene), PFA
(copolymer of tetrafluoroethylene and perfluoro alkylvinyl ether),
FEP (copolymer of tetrafluoroethylene and hexafluoropropylene),
ETFE (copolymer of tetrafluoroethylene and ethylene), PVDF
(polyvinylidene-fluoride (2 fluoride)), PCTFE
(polychlorotrifluoroethylene (3 fluoride)), ECTFE (ethylene-chloro
trifluoro ethylene copolymer), PVF (poly vinyl fluoride (polyvinyl
chloride)), SiO.sub.2 (silicon oxide film), SiN (silicon nitride
film) may be employed.
[0270] While the example of forming the stopper film to be stacked
on the guard electrode is shown in each of the aforementioned
eighth to eleventh embodiments, the present invention is not
restricted to this but the stopper film and the guard electrode may
be arranged on planarly different positions.
[0271] While the example of forming the electret film on the side
of the fixed electrode is shown in each of the aforementioned
seventh to twelfth embodiments, the present invention is not
restricted to this but the electret film may be formed on the side
of the movable electrode.
[0272] While the example of forming the stopper film on the side of
the fixed electrode is shown in each of the aforementioned seventh
to twelfth embodiments, the present invention is not restricted to
this but the stopper film may be formed on the side of the movable
electrode. When the electret film and the stopper film are formed
on different electrode sides, the electret film is deteriorated by
contact between the electret film and the stopper film, and hence
the electret film and the stopper film are preferably formed on the
same electrode side.
[0273] While the example of forming the stopper film is shown in
each of the aforementioned seventh to twelfth embodiments, the
present invention is not restricted to this but the guard electrode
may be employed as a stopper.
[0274] While the example where the ends of the projecting portion
412a are angular is shown in the aforementioned fifteenth
embodiment, the present invention is not restricted to this but
ends of a projecting portion 412f of a fixed electrode 41f having
recess portions 411f may be chamfered as in an fixed electrode
portion 2a shown in FIG. 58. Thus, the movable electrode 62 (see
FIG. 22) can be inhibited from catching the projecting portion
412f.
[0275] While the example where the surface of the movable substrate
7 is flat is shown in the aforementioned first embodiment, the
present invention is not restricted to this but recess portions
611a may be formed on a surface of a movable substrate 61a on a
side opposed to a fixed electrode portion 2 as in a movable
electrode portion 3f of an electrostatic induction power generating
device 120 shown in FIG. 59. Thus, projecting portions 412d of a
fixed electrode 41d come into contact with side surfaces of the
recess portions 611a of the movable substrate 61a when the movable
substrate 61a vibrates in a direction X, and hence a vibration
width of the movable substrate 61a can be adjusted by adjusting
widths of the recess portions 611a.
[0276] While the example where the surface of the movable substrate
7 is flat is shown in the aforementioned first embodiment, the
present invention is not restricted to this but stopper portions 64
made of an insulating film may be provided on a surface of a
movable substrate 61 on a side opposed to a fixed electrode portion
2 so as to hold upper ends of projecting portions 412d of a fixed
electrode 41d therebetween as in a movable electrode portion 3g of
an electrostatic induction power generating device 121 shown in
FIG. 60. Thus, the projecting portions 412d of the fixed electrode
41d and the side surfaces of the stopper portions 64 come into
contact with each other when the movable substrate 61 vibrates in a
direction X, and hence a vibration width of the movable substrate
61 can be adjusted by adjusting intervals of the stopper portions
64.
[0277] While the example of providing the projecting portion 401b
on the surface of the fixed electrode 2 is shown in the
aforementioned first embodiment, the present invention is not
restricted to this but a recess portion 611b and projecting
portions 612b for inhibiting a movable electrode 62 and conductive
layers 47 from coming into contact with each other may be provided
on a surface of a movable substrate 61b as in a movable electrode
portion 3h of an electrostatic induction power generating device
122 shown in FIG. 61 in place of provision of a projecting portion
on a surface of the fixed electrode 41e of a fixed electrode
portion 2v. At this time, the movable electrode 62 is formed on the
surface of the recess portion 611b.
[0278] While the example where the movable electrode portion 3
vibrates in the direction X is shown in the aforementioned first
embodiment, the present invention is not restricted to this but
recess portions 611c may be provided on a surface, opposed to a
fixed electrode portion 2, of a movable substrate 61c as in a
movable electrode portion 3i of an electrostatic induction power
generating device 123 shown in FIG. 62, and a movable electrode
portion 3i may be vibrated in a direction Y (perpendicular to the
plane of paper) perpendicular to the direction X by moving
projecting portions 412d of the fixed electrode 41d along the
recess portions 611c.
[0279] While the example of forming the protective film 63 on the
surfaces of the movable substrate 7, the movable electrode 62 and
the movable electrode 62a is shown in the aforementioned
thirty-eighth, the present invention is not restricted to this but
no protective film 63 may be formed as in an electrostatic
induction power generating device 124 shown in FIG. 63. For
example, a movable electrode portion 2f may be employed in a place
of an electrode portion 2r.
[0280] While the example of forming the stopper film 45a on the
surface of the projecting portion 412a of the fixed electrode 41a
is shown in the aforementioned seventeenth embodiment, the present
invention is not restricted to this but a conductive layer 50 may
be formed as in a fixed electrode portion 2w shown in FIG. 64.
Thus, an electric field resulting from electric charges stored in
electret films 43b formed to cover bottom surfaces of recess
portions 411a of the fixed electrode 41a can be inhibited from
reaching positions not opposed to main surfaces of the electret
films 43b.
[0281] While the example of forming the electret film on the
surface of the fixed electrode is shown in each of the
aforementioned seventh to twelfth embodiments, the present
invention is not restricted to this but the electret film may be
formed on a surface of a fixed substrate made of silicon as shown
in FIG. 65.
[0282] While the electrostatic induction power generating device
shown in each of the aforementioned first to forty-first
embodiments may be applicable for a wrist watch, a thermometer, a
temperature indicator, a passometer, a remote control, a portable
audio player, a keyless entry, a hearing aid, a pacemaker, a laser
pointer, an electric toothbrush, a sensor, an e-book, a cell-phone,
a digital camera, a game console, a refrigerator, a washing
machine, a dish dryer and a tire pressure sensor, for example.
[0283] While the example of applying each of the aforementioned
first to forty-first embodiments of the present invention to the
electrostatic induction power generating device as an electrostatic
operation device, the present invention is not restricted to this
but is also applicable to an electrostatic induction actuator, for
example, other than the electrostatic induction power generating
device.
* * * * *