Note: Descriptions are shown in the official language in which they were submitted.
21~93~7
SPECIFICATION
ELECTRICAL CONNECTOR WITH FILTER
Technical Field
This invention relates to an electrical connec-
tor equipped with a filter.
Background Art
In recent years, with the progress in perfor-
mance and processing speed of electric devices, it has
been demanded to suppress and/or attenuate interference
signals and noise signals. To this end, various types
of electrical connectors with a filter has been pro-
posed (Japanese Patent Application Laid-Open 59-184478,
Japanese Patent Application Laid-Open 59-184479, Ja-
panese Patent Application Laid-Open 62-180973 and
Japanese Patent Application Laid-Open 63-239900).
The above prior art proposes to provide a
structure in which a shield frame and a filter unit are
electrically connected by means of solder and mechani-
cally held.
In the above-mentioned structure, the shield
frame and the filter unit are electrically connected
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and mechanically held by means of solder. First, the
cost required for soldering is comparatively high.
Secondly, the filter unit is susceptible to crack by
heat generated during soldering. Also, there is a
possibility that solder leach occurs. Moreover, resi-
due of flux used during soldering adversely affects
component members of the electrical connector with a
filter with the passage of time. Furthermore, since
the soldered parts are rigid, they are not resistant to
expansion and shrinkage due to temperature cycle.
Disclosure of Invention
It is, therefore, an object of the present
invention to provide an electrical connector with a
filter which can solve the above problems.
The present invention has achieved the above
object by providing an electrical connector with a
filter comprising a shield frame, a filter unit having
holes, contact elements to be inserted respectively
into the holes, and a leaf spring interposed between
the shield frame and the filter unit,
the filter unit having a filter function corre-
sponding to the holes, and a ground electrode;
the ground electrode and the shield frame being
electrically connected by the leaf spring; and
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the filter unit and the shield frame being
mechanically secured and held by the leaf spring
(hereinafter referred to as the "first invention").
Also, the present invention has achieved the
above object by providing an electrical connector with
a filter comprising a shield frame, a filter unit
having holes, contact elements to be inserted respec-
tively into the holes and each having a stopper, a
fixture for allowing the contact elements to be insert-
ed, a leaf spring interposed between the shield frame
and the filter unit, and a body,
the filter unit having a filter function corre-
sponding to the holes and a ground electrode;
the ground electrode and the shield frame being
electrically connected by the leaf spring;
the filter unit and the shield frame being
mechanically secured and held by the leaf spring; and
the contact elements being pressed against the
filter unit by the fixture through the stoppers (herei-
nafter referred to as the "second invention").
It should be noted that the terms "the present
invention" as used herein includes both the first and
the second inventions.
The electrical connector with a filter of the
present invention can be preferably used for electronic
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devices, electronic equipment, etc. For example, it
can be desirably used for communication equipments,
electronic devices for automobiles, peripheral equip-
ments of computers, vending machines, ticket vending
machines, various electronic game devices including
"Pachinko" (Japanese pinball) machines and amusement
game machines.
Brief Description of Drawings
Fig. 1 is an exploded perspective view showing
a preferred embodiment of the electrical connector with
a filter according to the first invention;
Fig. 2 is a sectional view taken along line J-
J' of Fig. 1 and viewed in a direction as indicated by
arrows;
Fig. 3 is a sectional view showing another
embodiment of a filter unit;
Fig. 4 is a perspective view showing a pre-
ferred embodiment of the electrical connector with a
filter according to the second invention;
Fig. 5 is an exploded perspective view of the
electrical connector with a filter shown in Fig. 4;
Fig. 6 is an exploded perspective view showing
another preferred embodiment of the electrical connec-
tor with a filter according to the second invention;
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Fig. 7 is a sectional view taken along line K-
K' of Fig. 6 and viewed in a direction as indicated by
arrows; and
Figs. 8(A) to 8(C) are perspective views show-
ing various contact elements equipped with a stopper.
Best Mode for Carrying Out the Invention
The electrical connector equipped with a filter
according to the first invention will be described
hereinafter with reference to the drawings illustrating
its preferred embodiment.
Fig. 1 is an exploded perspective view showing
a preferred embodiment of the electrical connector with
a filter according to the first invention, Fig. 2 is a
sectional view taken on line J-J' of Fig. 1 and viewed
in a direction as indicated by arrows, and Fig. 3 is a
sectional view showing another embodiment of a filter
unit.
As shown in Figs. 1 and 2, the electrical
connector with a filter according to the first inven-
tion comprises a shield frame 32, a filter unit 20
having holes 21, contact elements 33 to be inserted
respectively into the holes 21, and a leaf spring 31
interposed between the shield frame 32 and the filter
unit 20. The shield frame 32, the leaf spring 31 and
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the filter unit 20 are firmly secured by a set pin 35.
If necessary, a body 34 may be preferably secured
firmly with these members in such a manner that the
body 34 accommodates the filter unit. The leaf spring
31 is so contoured as to contact a ground electrode 14
formed on the filter unit 20 and the shield frame 32,
thereby electrically connecting the ground electrode 14
with the shield frame 32. Further, the leaf spring 31
mechanically secures and holds the filter unit 20 and
the shield frame 32 (and, the body 34, if necessary).
The filter unit 20 has a single or a plurality
of holes 21 formed in an alumina substrate 11 so that
the contact elements 33 can be inserted therein respec-
tively. The filter unit 20 further has a filter func-
tion corresponding to the holes 21 and the ground elec-
trode. The term "filter function corresponding to the
holes" as used herein refers to a filter function
associated with the respective contact elements 33
inserted into the holes. In Figs. 2 and 3, the filter
function 10 is formed on the periphery of each of the
holes 21, but it should be noted that the filter func-
tion 10 is not necessary to be formed on the periphery
of all the holes 21. Also, the filter function 10 is
not necessary to be formed in the periphery of the hole
21. Alternatively, it may be formed, for example, in
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an area adjacent to the hole 21.
The number of holes 21 provided is generally e-
qual to that of the contact elements 33 provided.
The filter function 10 preferably comprises a
conductor, a dielectric substance and/or a ferrite.
Further, where a high electrostatic capacity is re-
quired, it is preferred that a multi-layer printed
ceramic condenser is used as the filter function 10.
Where the filter function 10 is composed of a conductor
and a dielectric substance, the filter function 10
comprises, as shown in Fig. 2, a lower electrode 12, an
upper electrode 14, a dielectric layer 13 interposed
between the lower electrode 12 and the upper electrode
14, and a protective glass layer 15 covering the upper
electrode 14 and the dielectric layer 13. In the
filter unit 20 shown in Fig. 2, the upper electrode 14
also serves as the ground electrode.
The filter function 10 shown in Fig. 3 compris-
es a conductor, a dielectric substance and a ferrite.
That is, in the filter function 10 shown in Fig. 3, the
ferrite 56 is provided on the periphery of the hole 21,
the lower electrode 12 is provided in such a manner as
to surround the ferrite 56, and there are further
provided the upper electrode 14, the dielectric layer
13 interposed between the lower electrode 12 and the
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upper electrode 14, and the protective glass layer 15
covering the upper electrode 14 and the dielectric
layer 13. In the filter unit shown in Fig. 3, the
upper electrode 14 also serves as the ground electrode.
It should be noted, however, that the filter
unit 20 is not limited to the above-mentioned embodi-
ments, and the filter unit 20 can be appropriately
varied in material, contour, construction, method of
manufacture, etc.
The filter unit 20 is preferably manufactured
by means of printing technique and particularly prefer-
ably manufactured by thick-film printing technique.
The filter function 10 is not limited to the
embodiment in which it is provided only at a single
surface of the alumina substrate 11. Alternatively, it
may be provided at both surfaces of the alumina sub-
strate 11 or it may be alternately provided at the
upper and the lower surfaces thereof.
Where the filter function 10 is configurated as
in the embodiments as shown in Figs. 2 and 3, the upper
electrode 14 may be used as the ground electrode and
the lower electrode 12 may be electrically connected to
the contact element 33. Alternatively, the lower
electrode 12 may be used as the ground electrode and
the upper electrode 14 may be electrically connected to
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the contact element 33. Further, in a filter function
in the filter unit 20, the upper electrode 1~ may be
used as the ground electrode and the lower electrode 12
may be electrically connected to the contact elements
33, and in another filter function, the lower electrode
12 may be used as the ground electrode and the upper
electrode 14 may be electrically connected to the
contact elements 33.
The leaf spring 31 may be of a material and/or
construction having spring properties or elastic prop-
erties and electrically conductive properties. For
example, a plate, a spring, a wire, a rubber, a resin,
or the like may be used as the leaf spring 31.
The alumina substrate 11 is not particularly
limited as a substrate, and other materials may be used
as far as they have electrical insulation properties.
The dielectric substance is not particularly
limited. It is preferred that the dielectric substance
is of a lead perovskite structure, and particularly
preferred that the dielectric substance comprises at
least one compound selected from the group consisting
of Pb(Mgl/3Nb2/3)O3, Pb(Znl/3Nb2/3)O3, PbTiO3 and
Bi2O3.
The contact elements 33 are inserted respec-
tively into the holes 21 formed in the filter unit 20
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and secured by the fixing means. The fixing means is
not particularly limited. For example, the contact
elements 33 may be secured by soldering from a single
or both surfaces of the filter unit 20. When the con-
tact elements 33 are secured to the filter unit 20 by
soldering, a crack may not occur if the filter unit 20
is pre-heated prior to soldering. After soldering, if
ultrasonic cleaning is effected, no residue of flux may
be remained and no adverse effect caused by a change
with time may occur.
For assembling the filter unit 20 having the
contact elements 33 inserted and secured therein into
the shield frame 32 (and the body 34, if necessary),
the leaf spring 31 is held between the shield frame 32
and the filter unit 20. With this configuration, the
ground electrode 14 of the filter unit 20 and the
shield frame 32 can be electrically connected to each
other, and the filter unit 20 and the shield frame 32
can be mechanically held without soldering. The number
of the leaf spring 31 is not limited to one and a
plurality of leaf springs may be employed in accordance
with necessity. The electrical connector with a filter
30 thus assembled has advantages that no cracks occur
which would otherwise occur due to heat produced during
soldering, that no solder leach occurs, and that no
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residue of flux for soldering is remained since the
shield frame 32 and the filter unit 20 are not sol-
dered. Further, the connector 30 is resistant to
temperature cycle.
The order of assembling the contact elements
33, the filter unit 20, the body 34, the shield frame
32, the leaf spring 31 and set pins 35 are varied
according to the contour of the connector, and there-
fore not particularly limited.
Next, the electrical connector equipped with a
filter according to the second invention will be de-
scribed in detail with reference to the preferred
embodiments thereof as illustrated in the drawings.
Fig. 4 is a perspective view showing a pre-
ferred embodiment of the electrical connector with a
filter according to the second invention, Fig. 5 is an
exploded perspective view of the electrical connector
with a filter shown in Fig. 4, Fig. 6 is an exploded
perspective view showing another preferred embodiment
of the electrical connector with a filter according to
the second invention, Fig. 7 is a sectional view taken
along line K-K' of Fig. 6 and viewed in a direction as
indicated by arrows, and Figs. 8(A) to 8(C) are per-
spective views showing various contact elements with a
stopper.
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In the following description, the same features
as those described in the first invention with refer-
ence to Figs. 1 to 3 are not described in detail, and
the description as to Fig. 1 to 3 are appropriately
applied to the same features of the second invention.
Also, members shown in Figs. 4 to 8, which are identi-
cal with those in Figs. 1 to 3, are denoted by the
identical reference numerals.
As shown in Figs. 4 to 7, the electrical con-
nector with a filter according to the second invention
comprises a shield frame 32, a filter unit 20 having
holes 21, contact elements 33 to be inserted respec-
tively into the holes 21 and each having a stopper 62,
a fixture 42 for allowing the contact elements 33 to be
inserted, a leaf spring 31 interposed between the
shield frame 32 and the filter unit 20, and a body 34.
The shield frame 32, the leaf spring 31, the filter
unit 20, the contact elements 33, the fixture 42, and
the body 34 are assembled together and secured to one
another by set pins 35.
Similar to the first invention, the leaf spring
31 is so contoured as to contact with the ground elec-
trode 14 of the filter unit 20 and the shield frame 32,
thereby electrically connecting the ground electrode 14
with the shield frame 32. The leaf spring 31 is inter-
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posed between the filter unit 20 and the shield frame32 so as to mechanically secure and hold the filter
unit 20, the shield frame 32 and the body 34.
The contact elements 33 are inserted into the
respective holes 21 from the bottom surface of the
filter unit 20. The contact elements 33 are inserted
into the fixture 42 from the lower portion of the
contact element 33, and then the fixture 42 is inter-
posed between the filter unit 20 and the body 34. The
body 34 preferably accommodates the filter unit 20.
The contact elements 33 are pressed against and secured
to the filter unit by the fixture 42 through the stop-
pers 62.
As for the filter unit 20, the filter function
10 and the ground electrode 14, the detailed descrip-
tion made with respect to the first invention is also
appropriately applied to the second invention.
For assembling the electrical connector with a
filter according to the second invention, for example,
the shield frame 32, the leaf spring 31, the filter
unit 20, the contact elements 33, the fixture 42, and
the body 34 are assembled together in this order and
secured to one another by the set pins 35. This order
of assembly enables the electrical connector with a
filter to be manufactured with no soldering step. It
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should be noted, however, that the order of assembly is
not particularly limited because the order is varied
according to the contour of the connector.
As for the leaf spring 31, the detailed de-
scription made with respect to the first invention is
also appropriately applied to the second invention.
The fixture 42 mechanically holds the contact
elements 33. Also, in particular, where the filter
function 10 comprises a conductor and a dielectric
substance, the fixture 42 electrically connects the
electrode composed of the conductor to the contact
element 33. The fixture 42 is not particularly limited
in material, contour, etc. For example, the fixture is
preferably a washer, a spring or a rubber. In Figs. 4
and 5, a rubber is used as the fixture 42, whereas in
Figs. 6 and 7, a washer is used as the fixture 42.
The stopper 62 of each contact element 33 is
not particularly limited in contour. It may take any
contour as far as it can press the contact element 33
against the filter unit 20 in cooperation with the
fixture 42. For example, contact elements as shown in
Figs. 8(A) to 8(C) are preferably used.
In the electrical connector with a filter 30
thus assembled, since the shield frame 32 and the
filter unit 20 are not soldered and the contact ele-
14
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ments 33 and the filter unit 20 are not soldered, nocracks occur, which would otherwise occur by heat pro-
duced during soldering. In addition, no solder leach
occurs at all, no residue of flux for soldering is
remained at all, and the connector is more resistant to
temperature cycle.
Examples of the electrical connector with a
filter according to the present invention will be
described hereinafter. It should be noted, however,
that the electrical connector with a filter according
to the present invention is not limited to such exam-
ples.
[Example 1]
The electrical connector with a filter shown in
Figs. 1 and 2 was made.
First, an Ag-Pd conductive paste was screen-
printed on both surfaces of the alumina substrate 11
having the holes 21 and on the inner wall surfaces of
the holes 21 in a pattern as serving as individual
electrodes of the filter function 10 and dried, fol-
lowed by firing for ten minutes at 850 C to form the
lower electrodes 12, 12'. Then, a dielectric paste
predominantly comprises Pb(Mgl/3Nb2/3)O3 and
Pb(Znl/3Nb2/3)O3 was screen-printed in such a manner as
to have an overlaid portion on the lower electrode 12,
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and dried. The dielectric paste may be screen-printed
once or a plurality of times. In this Example, the
screen-printing and drying were carried out three
times, followed by firing for ten minutes at a peak
temperature of 900 ~C to form the dielectric layer 13.
Further, an Ag-Pd conductive paste was screen-printed
in such a manner as to overlay on the dielectric layer
and not to contact directly the lower electrode 12 and
dried, followed by firing for ten minutes at 900 ~C to
form the upper electrode 14. Further, an over-coating
glass paste was screen-printed on the area of the lower
electrode exposed to the surface and the area other
than longitudinal opposite end portions of the upper
electrode and dried, followed by firing for ten minutes
at 530 C to form the protective glass layer 15. In
this manner, the filter unit 20 was made.
Then, the contact elements were inserted re-
spectively into the holes 21 of the filter unit 20 and
pre-heated to about 180 ~C. Thereafter, the contact
elements 33 were soldered and secured to the filter
unit 20 from both surfaces thereof by the solder 22 and
electrically connected to the lower electrodes 12, 12'.
Then, the flux was removed by means of ultrasonic
cleaning.
Subsequently, the leaf spring 31 was inserted
16
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between the filter unit 20 having the contact elements
33 secured thereto and the shield frame 32, and secured
to one another by the set pins 35 together with the
body 34. In this manner, the electrical connector with
a filter 30 was made. The leaf spring 31 electrically
connects the upper electrode 14 to the shield frame
32, and as a result the upper electrode 14 served as an
ground electrode and functioned to enhance the electro-
magnetic shielding effect together with the shield
frame 32. That is, the electrical connector with a
filter of this Example exhibits a high noise attenua-
tion effect. Further, since the contact elements 33
are soldered at both surfaces of the filter unit 20,
securing strength is very strong and reliability is
high.
[Example 2]
The electrical connector with a filter shown in
Fig. 3 was made.
First, a ferrite paste was screen printed on
the inner wall surface of each hole 21 of the alumina
substrate 11 having the holes 21 and dried, followed by
firing for ten minutes at 900 C to form the ferrite
layer 56. Then, an Ag-Pd conductive paste was screen-
printed on a single surface of the alumina substrate 11
and dried, followed by firing for ten minutes at 850 C
2l593s7
to form the lower electrode 12. Subsequently, the
dielectric layer 13, the upper electrode 14 and the
protective glass layer 15 were formed in the substan-
tially same manner as in Example 1. In this manner,
the filter unit 20 was made.
Then, the contact elements 33 were inserted
respectively into the holes 21 of the filter unit 20
and pre-heated to about 180 C. Thereafter, the con-
tact elements 33 were secured to the filter unit 20 by
soldering from one side surface thereof, and electri-
cally connected to the lower electrode 12. Then, the
flux was removed by ultrasonic cleaning.
Subsequently, the leaf spring 31 was inserted
between the filter unit 20 and the shield frame 32 in
the substantially same manner as in the Example 1 and
secured to one another by the set pins 35 together with
the body 34. In this manner, the electrical connector
with a filter 30 was made. The leaf spring 31 electri-
cally connects the upper electrode 14 to the shield
frame 32, and as a result the upper electrode 14 served
as a ground electrode and functioned to enhance the
electromagnetic shielding effect together with the
shield frame 32. That is, the electrical connector
with a filter of this Example exhibits a high noise
attenuation effect.
18
21S93S7
[Example 3]
The electrical connector with a filter shown in
Figs. 4 and 5 was made.
First, the filter unit 20 having the filter
function 10 and the ground electrode was made in accor-
dance with the substantially same manner as in the
Example 1.
Then, the contact elements 33 each having a
stopper 62 were inserted respectively into the holes 21
from the bottom surface of the filter unit 20 (from the
side where the filter function is not formed) and the
rubber 42, which serves as a fixture, having contact
element insertion holes was provided on the bottom
surface of the filter unit 10 in such a manner that the
contact elements 33 penetrate the insertion holes of
the rubber 42. Subsequently, the shield frame 32, the
leaf spring 31, the filter unit 20 and the body 34 were
assembled in this order and secured to one another by
the set pins 35. In this manner, the electrical con-
nector with a filter without any application of solder
was made.
In the electrical connector with a filter thus
manufactured, the upper electrode 14 of the filter
function 10 functioning as a ground electrode and the
shield frame 32 are electrically connected by the leaf
19
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spring 31. Also, the contact elements 33 pressed
against the filter unit 20 by the rubber 42 through the
stoppers 62 are electrically connected to the lower
electrode of the filter function 10. As a result, the
electrical connector with a filter of this embodiment
exhibits a high electromagnetic shielding effect and a
high noise attenuation effect. Moreover, since the
connector is manufactured by a simplified assembling
process comprising no soldering steps, the connector
has advantages that no cracks occurs, no residue of
flux remains, and the connector is resistant to temper-
ature cycle and has a high reliability.
[Example 4]
The electrical connector with a filter shown in
Figs. 6 and 7 was made.
First, the filter unit 20 having the filter
function 10 and the ground electrode was made in accor-
dance with the substantially same manner as in the
Example 1.
Then, the contact elements 33 each having a
stopper 62 were inserted respectively into the holes 21
from the bottom surface of the filter unit 20 (from the
side where the filter function is not formed) and the
washers 42 serving as fixtures were provided on the
bottom surface of the filter unit 20 in such a manner
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that the contact elements 33 penetrate the washers 42.
Subsequently, the shield frame 32, the leaf spring 31,
the filter unit 20 and the body 34 were assembled in
this order and secured to one another by the set pins
35. In this manner, the electrical connector with a
filter without any application of solder was made.
In the electrical connector with a filter thus
manufactured, the upper electrode 14 of the filter
function 10 functioning as a ground electrode and the
shield frame 32 are electrically connected by the leaf
spring 31. Also, the contact elements 33 pressed
against the filter unit 20 by the washers 42 through
the stoppers 62 are electrically connected to the lower
electrode of the filter function 10. As a result, the
electrical connector with a filter of this Example
exhibits a high electromagnetic shielding effect and a
high noise attenuation effect. Moreover, since the
connector of this Example is manufactured in a simpli-
fied assembling process comprising no soldering step,
the connector has advantages that no cracks occurs, no
residue of flux remains, and the connector is resistant
to temperature cycle and has high reliability.
[Example 5]
An electrical connector with a filter was made
in accordance with the substantially same manner as in
21
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the Example 4 except for employing springs in place of
the washers 42 as fixtures. The same results as in the
Example 4 were obtained.
Although the present invention has been de-
scribed in accordance with the preferred embodiments,
they are employed merely to help the understanding of
the present invention, and therefore various variations
and modifications can be made without departing from
the scope of the present invention.
Industrial Applicability
The electrical connector with a filter accord-
ing to the present invention not only exhibits a high
electromagnetic shielding effect but also a high atten-
uation effect for attenuating unnecessary frequencies
of the electromagnetic signal. Moreover, since the
filter unit and the shield frame are not secured by
soldering, cracks may not occur. Moreover, the connec-
tor is resistant to temperature cycle and has high
reliability. Particularly, in the electrical connector
with a filter according to the first invention, elec-
trical connection and mechanical holding can be real-
ized simply by assembling the shield frame, the leaf
spring and the filter unit (and the body, where neces-
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sary) and secured by set pins. Thus, the process canbe simplified. In the electrical connector with a
filter according to the second invention, since the
assembling process comprises no soldering step, the
press can be more simplified, and no cracks occurs and
no residue of flux remains. Moreover, the connector
becomes more resistant to temperature cycle and has a
higher reliability.
