close

Вход

Забыли?

вход по аккаунту

?

DESCRIPTION JP2000165993

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2000165993
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
piezoelectric speaker element used for a piezoelectric receiver, a piezoelectric buzzer or the like,
and more particularly to a piezoelectric speaker element having a structure in which lead wires
are soldered.
[0002]
2. Description of the Related Art A piezoelectric speaker element is incorporated in a case having
predetermined acoustic characteristics as a piezoelectric receiver, a piezoelectric buzzer or the
like, and the piezoelectric speaker element is mechanically vibrated by an electrical signal applied
from an external circuit. The air in the case is vibrated to extract desired acoustic characteristics.
[0003]
For example, as shown in FIG. 4, the piezoelectric sounding body element is provided with a gap
of about 0.5 mm in the outer peripheral portion of the disc-shaped piezoelectric ceramic
substrate 41, and for example The piezoelectric body 40 (not shown in the figure) is bonded to
the metal diaphragm 44.
[0004]
As a method of forming the front side electrode and the back side electrode, a thick film method
13-04-2019
1
using screen printing or a thin film method such as sputtering is used.
Further, after imparting the piezoelectric characteristics, the piezoelectric body 40 is adhered to
the metal diaphragm 44 via the conductive resin adhesive (not shown in the figure).
[0005]
Further, as a method of connecting the piezoelectric sounding element and the external circuit, a
method of soldering a lead wire directly to a part of the surface side electrode 42 and a part of
the metal diaphragm 44 is often used.
In the figure, the soldered portion of the surface side electrode 42 is shown at 45 and the
soldered portion of the metal diaphragm 44 is shown at 46.
[0006]
However, when attempting to solder the lead wire to the soldering area 45, 46 of the
conventional piezoelectric sounding element, the soldering iron is pressed and its temperature,
For example, 350 ° C. is locally added to the piezoelectric ceramic substrate 41 via the surface
side electrode 42. Moreover, this temperature instantaneously reaches high temperature. That is,
a large temperature gradient is generated around the soldered portion 45 of the piezoelectric
ceramic substrate 41, and a large internal stress is locally generated due to thermal expansion.
[0007]
Further, in combination with an external pressure or the like pressed from the soldering iron, a
crack may occur in the soldered portion.
[0008]
The piezoelectric ceramic substrate 41 is thin, about 0.1 mm in thickness, and once cracked,
metal migration occurs between the front side electrode and the back side electrode, which may
result in short circuit or insulation failure.
13-04-2019
2
In addition, when defects such as pin holes and micro cracks are included in the material of the
piezoelectric ceramic substrate 41, the cracks may be accelerated by heat and pressure at the
time of soldering, leading to insulation failure.
[0009]
The present invention has been made in view of the above problems, and an object thereof is to
provide a piezoelectric sounding element capable of preventing migration or the like occurring at
the time of soldering.
[0010]
According to the present invention, a front side electrode and a back side electrode are formed
on both sides of a disk-shaped piezoelectric ceramic substrate, and a conductive resin adhesive is
interposed in the back side electrode. In the piezoelectric sounding element in which a metal
diaphragm is bonded and a lead wire is soldered to the front side electrode, an electrode notch is
formed in the back side electrode, and a portion immediately above the electrode notch is
formed. It is a piezoelectric sounding element characterized in that a lead wire is soldered.
[0011]
Preferably, a positioning marker that can be recognized from the surface side electrode side is
formed on the outer peripheral side surface of the piezoelectric ceramic substrate in the region
where the electrode notch portion is formed.
[0012]
According to the present invention, the piezoelectric body provided with the surface side
electrode and the back side electrode on both main surfaces of the piezoelectric ceramic
substrate is bonded to the metal diaphragm, and the lead wire is directly soldered to the surface
side electrode. At the same time, even if microcracks or the like generated during soldering are
generated on the piezoelectric ceramic substrate, the back surface side electrode does not exist
on the back surface side of the ceramic substrate at the soldering portion.
For this reason, metal migration and short circuit are less likely to occur between the front side
electrode and the back side electrode.
13-04-2019
3
In addition, even if defects such as pinholes and micro cracks exist in the material of the
piezoelectric ceramic substrate itself, the characteristics are not deteriorated at all.
[0013]
Also, when forming the back side electrode on the back side of the piezoelectric ceramic
substrate, a marker capable of recognizing the position of the electrode notch is formed on the
outer peripheral side of the piezoelectric ceramic substrate, so the piezoelectric body is bonded
to the metal diaphragm After that, lead wires can be soldered to the surface-side electrodes with
reference to the markers, and the piezoelectric sounding element that can obtain the abovementioned action can be manufactured with enhanced mass productivity.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the piezoelectric speaker of the
present invention will be described in detail with reference to the drawings.
[0015]
1 is an external perspective view of the piezoelectric sounding element according to the present
invention with the lead wire omitted, FIG. 2 is an external perspective view of the back side of the
piezoelectric body, and FIG. 3 is a cross section of the piezoelectric sounding element FIG.
[0016]
The piezoelectric sounding body element 10 of the present invention is composed of a
piezoelectric body 1, a metal diaphragm 2, and lead wires 3 and 4.
The piezoelectric body 10 is composed of the piezoelectric ceramic substrate 11, the front side
electrode 12, the back side electrode 13, and the marker 15.
[0017]
The piezoelectric ceramic substrate 11 is made of a piezoelectric material such as PZT (lead
13-04-2019
4
zirconate titanate) or PZ (lead zirconate), and is a circular thin plate (about 0.1 mm).
As shown in FIG. 1 and FIG. 2, on the both surfaces, a circular surface-side electrode 12 and a
substantially circular back surface-side electrode 13 are formed concentrically.
This electrode is formed, for example, by a thick film method in which a conductive paste such as
silver or silver palladium is printed and baked.
[0018]
In addition, as shown in FIG. 2, the back surface side electrode 13 does not have an electrode
formed in a part of the outer peripheral portion toward the center direction with a predetermined
width (the back surface of the piezoelectric ceramic substrate 1 is exposed) An electrode notch
14 is formed.
[0019]
The center of the electrode notch portion 14 corresponds to the soldered portion of the lead wire
3 of the surface side electrode 12 shown in FIG.
The electrode notch portion 14 has a substantially rectangular shape, and one side is about 6
mm.
This is because when the lead wire 3 is soldered S to the soldered portion 5 of the surface
electrode 12, the diameter of the solder becomes approximately 2 mm, and if it is about 3 times
that, the heat low effect at the time of solder bonding It does not affect. The shape of the
electrode notch portion 14 may be U-shaped or circular as long as the opening dimension is 6
mm or more.
[0020]
Further, a marker 15 is formed on a portion corresponding to the electrode notch portion 14,
that is, on the outer peripheral side surface of the piezoelectric ceramic substrate 11 at the
13-04-2019
5
center in the width direction of the electrode notch portion 14. This marker is formed by baking
simultaneously formed by screen printing, for example, when forming the above-mentioned back
side electrode 13. Specifically, a small print pattern is formed at the position of the marker 15,
and can be easily formed on the side surface of the piezoelectric ceramic substrate 11 by vacuum
suction from below at the time of screen printing.
[0021]
The piezoelectric body 1 having such a structure is bonded to the metal diaphragm 2 having a
diameter larger than that of the piezoelectric body 1. Specifically, the back surface side electrode
13 of the piezoelectric body 1 is an adhesive surface. The metal diaphragm 2 is made of a brass
plate or an iron-based thin plate, and is treated with a curing accelerator for adhesion as
required. The adhesive 16 can be exemplified by the conductive acrylic anaerobic adhesive 19
and the like. Thereby, the back surface side electrode 13 and the metal diaphragm 2 will be
connected minutely and electrically.
[0022]
The lead wires 3 and 4 are soldered S to the piezoelectric body 1 and the metal diaphragm 2 to
form the piezoelectric sounding element 10. Specifically, as shown in FIG. 1, the lead wire 3 is
soldered to the soldered portion 5 of the front side electrode 12 and the lead wire 4 is soldered
to the soldered portion 6 of the metal diaphragm 2. Thereby, the piezoelectric sounding body
element 10 is achieved.
[0023]
At this time, when the lead wire 3 is soldered to the surface side electrode 12, the electrode cut
portion 14 of the back side electrode can be known by the marker 15, and the lead wire 3 is
considered to be the center It will be soldered. Further, the solder portion 6 on the metal
diaphragm 2 is determined based on the position of the marker 15.
[0024]
13-04-2019
6
The drive signal from the drive signal circuit is supplied via the leads 3 and 4. Then, the lead wire
3 is directly applied to the front side electrode 12, and the lead wire 4 is applied to the back side
electrode 13 through the metal diaphragm 2 and the conductive adhesive 16.
[0025]
According to the present invention, it is possible to solve various problems that occur when
welding the lead wire 3 to the electrode 12 with the solder S on this surface side. That is,
although the lead wire 3 is held by the soldered portion 5 of the surface side electrode 12 and
applies heat which can melt the solder from a soldering iron (not shown), the rapid heat and
pressure applied locally Thus, even if a crack occurs in the piezoelectric ceramic substrate 11,
the back surface side electrode 13 does not exist on the back surface of the soldered portion 5.
For this reason, the front side electrode 12 and the back side electrode 13 do not short-circuit
due to migration of silver or the like, and an insulation failure does not occur. That is, even if the
migration proceeds from the solder portion 5 toward the back surface side electrode 13, the
opening size of the electrode notch portion 14 is about 6 mm, so that the progression can be
prevented. That is, in order to reach the back surface side electrode 13 from the crack portion via
the back surface of the piezoelectric ceramic substrate 11, a long distance must be passed, and
migration does not proceed.
[0026]
Also, the conductive adhesive 16 adheres to the electrode notch portion 14 with the metal
diaphragm 2 with a thickness of 5 to 20 μm, and even if the piezoelectric ceramic substrate 11
directly below the solder portion 5 is cracked. The adhesive layer 16 is present in the form of
sealing the crack, and migration with the metal diaphragm 2 does not occur. Here, forming a
thickness of 5 to 20 μm of the adhesive layer in the electrode notched portion 14 can be
achieved without any special operation. This is because the adhesive layer 16 is formed with the
same thickness in the electrode notched portion 14 without the electrode, since the surrounding
back surface side electrodes 13 are formed with substantially the same thickness.
[0027]
Furthermore, when the adhesive strength of the piezoelectric body 1 bonded to the metal
diaphragm 2 is examined, a difference is recognized between the presence of the back surface
13-04-2019
7
side electrode 13 and the place where there is no electrode corresponding to the electrode notch
portion 14 The adhesion strength between the piezoelectric ceramic substrate 11 and the metal
diaphragm 2 at the electrode notch portion 14 is higher. Thereby, the adhesion strength of the
electrode notch portion 14 is high, and even when the lead wire 3 is soldered to the front side
electrode 12, even if the lead wire 3 is strongly pulled so as to peel the piezoelectric body 1 from
the metal diaphragm 2, Since the piezoelectric body 1 and the metal diaphragm 2 do not
separate, it is possible to make a piezoelectric sounding element with high reliability.
[0028]
Although the lead wire 4 is described as being joined to the metal diaphragm 2 by the solder S in
the above-described embodiment, it can be arbitrarily changed depending on the signal supply
structure of the external drive circuit. For example, a pressure contact terminal may be used.
[0029]
As described above, according to the present invention, an electrode notch is formed in a part of
the back surface side electrode, and a lead wire is soldered to the surface side electrode portion
corresponding to the electrode notch. There is.
[0030]
Therefore, even if a local heat is applied excessively at the time of lead attachment and a crack or
the like occurs in the piezoelectric ceramic substrate, it is possible to substantially prevent the
occurrence of migration.
As a result, a short circuit between the front side electrode and the back side electrode or an
insulation failure does not occur.
[0031]
In addition, since the adhesive strength between the piezoelectric ceramic substrate directly
below the lead wire to be soldered and the metal diaphragm is high, a highly reliable
piezoelectric sounding element having high lead wire attachment strength can be obtained.
13-04-2019
8
[0032]
Further, after bonding the piezoelectric vibrating body to the metal vibrating plate, when
soldering the lead wire to the surface side electrode, it may be soldered on the basis of the
marker, and the workability is greatly improved.
In addition, since this marker can be formed simultaneously with the formation of the back
surface side electrode, solder bonding can be performed at a predetermined position.
13-04-2019
9
Документ
Категория
Без категории
Просмотров
0
Размер файла
17 Кб
Теги
description, jp2000165993
1/--страниц
Пожаловаться на содержимое документа