USO0RE40709E
(19) United States (12) Reissued Patent
(10) Patent Number:
Akahane et a]. (54)
US RE40,709 E
(45) Date of Reissued Patent:
PIEZOACTUATOR AND DRIVE CIRCUIT
5,563,478 A
THEREFOR
5,955,819 A 6,054,795 A
(75) Inventors: Hidehiro Akahane, SuWa (JP); Akihiro
10/1996 Suganuma 9/1999 Takano etal. 4/2000 Yamamoto et a1.
i
'
a
SaWada, SuWa (JP), Makoto Furuhata,
May 12, 2009
iltlmfris
a
su a
6,661,154 B2
12/2003 Shibatani
SuWa (JP) FOREIGN PATENT DOCUMENTS
(73) Assignee: Seiko Epson Corporation, Tokyo (JP) (21)
Appl. No.: 11/591,409 '
(22)
.
Med‘
'
'
Nov‘ 1’ 2006 Related US. Patent Documents
Relssue Of-
(64) Patent No.:
09608274 11-215858
8/1999
JP
2000-078867
3/2000
JP
2000-188882
7/2000
JP
2000_295876
100000
JP
2001-286164
10/2001
Jan 11 , 2005
Primary ExamineriMark Budd
10/109356 Mar. 26, 2002
(74) Attorney, Agent, or FirmiMichael T. Gahrik (57) ABSTRACT
Foreign Application Priority Data
A pieZoactuator has a diaphragm, and the diaphragm has ?at
(JP) ....................................... .. 2001-91112
piezoelectric elements that oscillate in a longitudinal oscilla
tion mode and a sinusoidal oscillation mode. A ?rst elec trode for detectin g oscillation ' ' ' ' ' ' ' in the longitudinal oscillation
Int‘ Cl‘
(200601)
mode, and a second electrode for detecting the amplitude of oscillation in the sinusoidal oscillation mode, are disposed
US. Cl. ........................... .. 310/316.01; 310/316.02; _
_
_
on the Surface of the diaphragm' when the piezoactuator is
310/323'02
driven With a drive signal, the phase difference of a ?rst
Fleld of Classl?eatlen Search ~~~~~~~~~~~ ~~ 31061601, _ _ 31061602’ 323-92; 318/116
detection signal output from the ?rst electrode and a second detection signal output from the second electrode is
See aPPheanOn ?le for Complete Search hlstory-
detected. The frequency at Which the detected phase differ
_
(56)
“H997
JP JP
6,841,919
H011‘ 41/08
(58)
1/1994 11/1997
Issued;
Mar. 27, 2001
(52)
06-014565 9-294384
App1_ NO_; Filed:
(30)
(51)
JP JP
ence becomes the maximum phase difference is then
References Clted Us‘ PATENT DOCUMENTS 5,233,274 A
obtained, and a drive signal of a matching frequency is applied to the piezoelectric elements.
8/1993 Honda et a1.
17 Claims, 29 Drawing Sheets
200
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2805 VOLTAGE 1
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S
ADJUSTING
CIRCUIT
INITIAL DRIVE SIGNAL
US. Patent
May 12, 2009
Sheet 1 0f 29
US RE40,709 E
FIG. 1
72
FIG. 2
71
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US. Patent
May 12, 2009
Sheet 2 0f 29
US RE40,709 E
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US. Patent
May 12, 2009
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Sheet 3 0f 29
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300 a 300
FIG. 4
FIG. 5
US RE40,709 E
300D
US. Patent
May 12, 2009
Sheet 4 0f 29
US RE40,709 E
SDR(+V<==-V) (DRIVE SIGNAL) SD‘I
FlG. 6
[OPPOSITE]
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FIG. 7
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US. Patent
May 12, 2009
Sheet 5 0f 29
DIRECTION OF
ROTOR ROTATION
100
FIG. 10
US RE40,709 E
US. Patent
May 12, 2009
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Sheet 10 0f 29
A
US RE40,709 E
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FIG. 15
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FIG. 16
US. Patent
May 12, 2009
Sheet 12 0f 29
US RE40,709 E
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FIG. 18
US. Patent
May 12, 2009
Sheet 14 0f 29
US RE40,709 E
202 (D- V CONVERSION CIRCUIT
SD‘
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PHASE
AVERAGE
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DETECTOR
VOLTAGE
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9
202A
FIGQO
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2028
US. Patent
May 12, 2009 801
Sheet 15 0f 29
US RE40,709 E
US. Patent
May 12, 2009
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Sheet 18 0f 29
US RE40,709 E
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US. Patent
May 12, 2009
Sheet 19 0f 29
US RE40,709 E
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