Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2001-02-07
2003-04-22
Jaworski, Francis J. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S463000, C310S334000, C310S335000, C310S322000, C310S323090
Reexamination Certificate
active
06551247
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an ultrasonic probe to be used in an ultrasonic diagnostic apparatus or the like.
DESCRIPTION OF THE PRIOR ART
An ultrasonic probe is used, for example, in an ultrasonic diagnostic apparatus for a human body. One of the conventional ultrasonic probes is disclosed in Japanese Patent Laid-Open Publication No. Hei 8-122310.
FIG. 17
shows a structure of this conventional ultrasonic probe. In
FIG. 17
, a piezoelectric element
31
is an element for transmitting and receiving an ultrasonic wave, and each face thereof is provided with an electrode. An acoustic matching layer
37
is made of conductive material and is provided on a face of one of the electrodes to efficiently transmit and receive an ultrasonic wave for a subject to be examined (human body). The ultrasonic probe further comprises a conductive layer
40
provided on a high molecular film
41
by deposition or other proper operations so as to be brought into contact with the acoustic matching layer
37
. An acoustic lens
38
is provided on a face of the high molecular film to focus the ultrasonic wave. An FPC
34
is provided on the other electrode so as to form a conductive pattern, and a backing material
39
is provided on a face of the FPC
34
. This structure allows an electrical connection to be maintained even if the piezoelectric element
31
is cracked by an external mechanical impact, and thereby provides a feature that the piezoelectric element is less likely to fail and stable quality is provided.
Referring to
FIG. 17
more specifically, the piezoelectric element
31
is provided with a positive electrode
32
on one face thereof and with a ground electrode
33
on the other face thereof. Each of these electrodes
32
,
33
is made of baked-silver formed by baking a composite of glass and silver, or of gold plating, sputtering or deposition, and has a thickness of 0.5 to 10 &mgr;m to provide a short pulse characteristic. The positive electrode
32
is provided, on a back face thereof, with a laminate of a positive electrode side conductive layer
35
and a positive electrode side base material layer
36
stacked in this order. The positive electrode side base material layer
36
is made of high molecular film or the like, and the positive electrode side conductive layer
35
is formed on this base material layer by plating, sputtering or deposition with metallic material such as copper or gold, or by fixing a metal foil thereto, and further is formed into a proper pattern, if necessary. Further, the backing material
39
is provided on a back face of the positive electrode side base material layer
36
so that a short pulse characteristic is achieved by braking the piezoelectric element
31
.
Further, the acoustic matching layer
37
made of conductive material such as graphite is laminated on a front face of the ground electrode
33
(on the side of a subject to be examined), and a ground electrode side conductive layer
40
and a ground electrode side base material layer
41
are laminated on a front face of the acoustic matching layer
37
.
The ground electrode side base material layer
41
is made of high molecular film or the like, and the ground electrode side conductive layer
40
is formed on this base material layer
41
by plating, sputtering or deposition with such metal as copper or gold, or by fixing a metallic foil thereto, where the ground electrode side conductive layer
40
is disposed below the base material layer
41
as shown in FIG.
17
. Further, an acoustic lens
38
is provided on a front face of the ground electrode side base material layer
41
to focus the ultrasonic wave.
In this structure, a mechanical deformation is produced in the piezoelectric element
31
by an electric signal supplied between the positive electrode side conductive layer
35
and the ground electrode side conductive layer
40
from a main body of an ultrasonic diagnostic apparatus (not shown), and thereby an ultrasonic wave is transmitted.
The ultrasonic wave transmitted from this piezoelectric element
31
, after the propagation efficiency thereof into a human body is enhanced by the acoustic matching layer
37
and the wave is focused by the acoustic lens
38
, is transmitted into the human body (not shown). The ultrasonic wave transmitted into the human body produces a reflective wave when it is reflected by an interface of tissues in the human body. The reflective wave, after passing the same path as the transmitted ultrasonic wave in a reverse direction, is received by the piezoelectric element
31
and is transformed back into an electric signal to be sent as a received signal to the ultrasonic diagnostic apparatus. Based on this received signal, the ultrasonic diagnostic apparatus forms an image indicative of the information inside the human body to make a diagnosis. Another conventional ultrasonic probe is disclosed in Japanese Patent Laid-Open Publication No. Hei 11-276479.
FIG. 18
is a schematic perspective view of another conventional ultrasonic probe. In explaining this drawing, the word “up” means a direction from a lower part of the drawing to an upper part thereof. In
FIG. 18
, a piezoelectric element
51
is an element for transmitting and receiving an ultrasonic wave. A first electrode
53
and a second electrode
52
each being provided on one face of the piezoelectric element
51
, respectively, are electrodes for applying a voltage to the piezoelectric element
51
. The first electrode
53
works as a GND and forms a turning electrode which passes along a side face of the piezoelectric element extending parallel with a short axis direction thereof, and reaches a portion of a face of a backing material. The first electrode
53
of the piezoelectric element
51
is electrically connected to a copper foil
55
, and the second electrode
52
is a signal electrode electrically connected to a flexible print circuit (FPC)
54
with a wiring pattern formed thereon. Each electrode is disposed on one of end faces of the piezoelectric element, respectively, in the short axis direction. Further, the piezoelectric element
51
and a plurality of acoustic matching layers are cut along a direction parallel with the short axis to form channel dividing grooves
56
, so that a plurality of piezoelectric elements are arranged to align with the short axis direction.
A first acoustic matching layer
57
a
is provided on an upper face of the first electrode
53
(to face the subject to be examined) so that the ultrasonic wave may be efficiently transmitted and received thereby. A second acoustic matching layer
57
b
is provided on an upper face of the first acoustic matching layer
57
a
so that the ultrasonic wave may also be efficiently transmitted and received thereby. An acoustic lens
58
is provided on the second acoustic matching layer
57
b
to focus the ultrasonic wave. Further, a backing material
59
is provided on a lower face of the second electrode
52
in order to absorb undesired ultrasonic waves as well as to support the piezoelectric element
51
.
In the conventional ultrasonic probe shown in
FIG. 17
; however, the high molecular film
41
is provided to be extended as an electrical terminal and is not contemplated as an acoustic matching layer. Accordingly, there occurs a problem in that the efficiency in transmitting and receiving the ultrasonic wave is reduced, and further the frequency characteristic is degraded. Further, there is another problem in that an insulator of a signal electrical terminal disposed between the piezoelectric element and the backing material is generally thick, which has a negative effect on the damping of the backing material and degrades the acoustic characteristic of the ultrasonic probe, especially the frequency characteristic thereof.
Further, in the conventional ultrasonic probe described above, the acoustic matching layer
37
is provided in order to efficiently propagate the ultrasonic wave transmitted from the piezoelectric element
31
(generally having a high acoustic impedance of about 25 t
Fukase Hirokazu
Koishihara Yasushi
Saito Koetsu
Takeda Junichi
Jaworski Francis J.
Jung William
Matsushita Electric - Industrial Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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