Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
1998-06-30
2003-01-14
Budd, Mark O. (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
C310S344000
Reexamination Certificate
active
06507139
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus, such as a piezoelectric resonance device, having an electronic component located on a surface of a package member with a space provided between the electronic component and the package member.
2. Description of the Related Art
Some electronic devices require that a portion thereof does not contact a printed circuit board or substrate when mounted on the printed circuit board or substrate or the like. For instance, in a piezoelectric resonator, a resonating section thereof must be arranged such that a sufficient space between the resonating section and the printed circuit substrate is provided in order to prevent interference with the oscillation of the resonating section. In case of an exothermic electronic component, it is necessary to mount the electronic component such that a sufficient space between the printed circuit board or substrate and the component is provided in order to prevent heat from conducting to the printed circuit board or substrate and other nearby elements.
Various structures have been proposed for a piezoelectric resonator in order to create such a space.
FIG. 17
is a partially cutaway section view showing one example of a prior art structure for mounting a piezoelectric resonator.
As seen in
FIG. 17
, electrode lands
52
a
and
52
b
are located on a substrate
51
. A piezoelectric resonator
53
is mounted in contact with the electrode lands
52
a
and
52
b.
The piezoelectric resonator
53
has a structure in which a terminal electrode
53
b
is located at one end of a piezoelectric plate
53
a
and a terminal electrode
53
c
is located at the other end. It is noted that a resonance electrode not shown is connected to the terminal electrodes
53
b
and
53
c.
The terminal electrodes
53
b
and
53
c
are connected to the electrode lands
52
a
and
52
b
via conductive adhesives
54
a
and
54
b
applied so as to have a certain thickness to prevent interference with the oscillation of a resonating section of the resonator
53
.
That is, a gap
55
is created between the piezoelectric resonator
53
and an upper surface
51
a
of the substrate
51
by increasing a thickness of the conductive adhesives
54
a
and
54
b.
However, because the conductive adhesives
54
a
and
54
b
are liquid when they are applied, the conductive adhesive material is liable to flow along the upper surface
51
a
toward the center of the piezoelectric resonator
53
as shown by arrows A
1
and A
2
in FIG.
17
. As a result, the resonating section is joined to the upper surface
51
a
of the substrate
51
via the conductive adhesive in the mounting structure, thereby degrading the resonating characteristics of the resonator
53
. In addition, because the conductive adhesives
54
a,
54
b
flow and extend along the upper surface
51
a,
the vertical dimension of the gap
55
is reduced and cannot be accurately or reliably provided.
Further, because the liquid conductive adhesives
54
a
and
54
b
are hardened after the application, the size and vertical dimension of the space
55
varies. Often, the resonating section of the resonator
53
contacts the upper surface
51
a
of the substrate
51
, thereby damaging the resonating characteristics of the resonator
53
.
In order to eliminate the aforementioned problems, there has been proposed a mounting structure in which spacers
56
a
and
56
b
are interposed between the terminal electrodes
53
b
and
53
c
and the electrode lands
52
a
and
52
b
as shown in FIG.
18
. The spacers
56
a
and
56
b
are made of an electrically conductive material such as metal and are joined to the terminal electrodes
53
b
and
53
c
as well as the electrode lands
52
a
and
52
b
via conductive adhesive or solder. A space
55
A is defined between the piezoelectric resonator
53
and the upper surface
51
a
of the substrate
51
by the vertical dimension of the spacers
56
a
and
56
b.
However, this structure requires preparation of spacers
56
a
and
56
b
having a very accurate size and shape and also requires a difficult and time-consuming process of applying the spacers
56
a
and
56
b
to mount the piezoelectric resonator
53
.
Meanwhile, there has been disclosed a small package structure for storing a piezoelectric resonator and the like in Japanese Patent Laid-Open No. Hei. 5-83074.
FIGS. 19
a
and
19
b
are a partially cutaway plan view and a section view, respectively, showing the package structure of this prior art device.
The electronic component
61
includes an insulating substrate
62
and a cap
63
. A piezoelectric resonator
64
is stored within the package. Further, through hole electrodes
65
a
-
65
c
are formed so as to extend through the substrate
62
. The through hole electrodes
65
a
-
65
c
are constructed by creating through holes extending through the substrate
62
and by applying an electrode material on the inner peripheral surfaces of the through holes. The inner peripheral surfaces of the through holes and the electrodes extend to the upper and lower surfaces so as to form flange-like portions.
The piezoelectric resonator
64
is joined to the through hole electrodes
65
a
-
65
c
via conductive adhesives
66
a
-
66
c.
The conductive adhesives
66
a
-
66
c
are disposed in the through hole electrodes
65
a
-
65
c
and are joined to the flange-like portion at the upper surface of the substrate
62
of the through hole electrodes
65
a
-
65
c.
It is thought that the electronic component
61
allows an area outside of the cap
63
to be reduced so that the device can be miniaturized because the piezoelectric resonator
64
is led to the outside via the through hole electrodes
65
a
-
65
c.
However, because the piezoelectric resonator
64
is joined to the through hole electrodes
65
a
-
65
c
via the conductive adhesives
66
a
-
66
c
in the electronic component
61
, oscillation of the resonating section is damaged by the conductive adhesives
66
a
-
66
c
which flow and spread during application thereof similar to the case of the mounting structure
51
shown in FIG.
17
. In addition, similar to the prior art device shown in
FIG. 17
, the prior art device in FIG.
19
(
b
) experiences a problem of not being able to reliably provide an accurate vertical dimension of the gap between the resonator
64
and the substrate
62
, which problem is caused by the upper portions of the electrodes
65
a
-
65
c
and the adhesives
66
a
-
66
c
extending along and spreading out along the upper surface of the substrate
62
.
As described above, there have been problems with degrading resonance characteristics caused by the mounting structure
51
shown in FIG.
17
and by the electronic component
61
shown in
FIG. 19
because the space having a sufficient size or vertical dimension cannot be reliably provided due to the fluidity and spreading of the conductive adhesive.
Further, the mounting structure shown in
FIG. 18
has had problems with the manufacturing and assembly process being complicated and costly because the spacers
56
a
and
56
b
have to be used.
SUMMARY OF THE INVENTION
To overcome the problems described above, the preferred embodiments of the present invention provide an apparatus including an electronic component which is arranged and constructed to be fixed firmly to a package member with a space being reliably provided therebetween and to allow the component to be easily manufactured.
The preferred embodiments of the present invention provide an electronic component including a package member; a via hole electrode provided so as to extend through the package member and to protrude from a first surface of the package member; an electronic component located on the first surface of the package member with a space defined therebetween; the space between the electronic component and the first surface of the package member being determined by a protruding portion of the via hole electrode extending from the surface of the package member; and a joining member joining the electronic co
Inoue Jiro
Ishino Satoshi
Kaida Hiroaki
Kubota Kenji
Maesaka Michinobu
Budd Mark O.
Keating & Bennett LLP
Murata Manufacturing Co. Ltd.
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