Technical Field
[0001] This invention relates to an electrical connector equipped with a filter.
Background Art
[0002] In recent years, with the progress in performance 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 proposed (Japanese Patent Application Laid-Open 59-184478, Japanese Patent Application
Laid-Open 59-184479, Japanese Patent Application Laid-Open 62-180973 and Japanese
Patent Application Laid-Open 63-239900).
[0003] 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 mechanically held.
[0004] In the above-mentioned structure, the shield frame and the filter unit are electrically
connected 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,
residue 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
[0005] It is, therefore, an object of the present invention to provide an electrical connector
with a filter which can solve the above problems.
[0006] 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 corresponding to the holes, and a ground
electrode;
the ground electrode and the shield frame being electrically connected by the leaf
spring; and
the filter unit and the shield frame being mechanically secured and held by the
leaf spring (hereinafter referred to as the "first invention").
[0007] 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 respectively into the holes and each having a stopper, a fixture
for allowing the contact elements to be inserted, a leaf spring interposed between
the shield frame and the filter unit, and a body,
the filter unit having a filter function corresponding 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 (hereinafter referred to as the "second invention").
[0008] It should be noted that the terms "the present invention" as used herein includes
both the first and the second inventions.
[0009] The electrical connector with a filter of the present invention can be preferably
used for electronic devices, electronic equipment, etc. For example, it can be desirably
used for communication equipments, electronic devices for automobiles, peripheral
equipments of computers, vending machines, ticket vending machines, various electronic
game devices including "Pachinko" (Japanese pinball) machines and amusement game machines.
Brief Description of Drawings
[0010]
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 preferred 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 perspective views showing various contact elements equipped
with a stopper.
Best Mode for Carrying Out the Invention
[0011] 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.
[0012] 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.
[0013] As shown in Figs. 1 and 2, the electrical connector with a filter according to the
first invention 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 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).
[0014] 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 respectively. The filter
unit 20 further has a filter function corresponding to the holes 21 and the ground
electrode. 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 function 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 an area adjacent to the hole 21.
[0015] The number of holes 21 provided is generally equal to that of the contact elements
33 provided.
[0016] The filter function 10 preferably comprises a conductor, a dielectric substance and/or
a ferrite. Further, where a high electrostatic capacity is required, 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.
[0017] The filter function 10 shown in Fig. 3 comprises 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 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.
[0018] It should be noted, however, that the filter unit 20 is not limited to the above-mentioned
embodiments, and the filter unit 20 can be appropriately varied in material, contour,
construction, method of manufacture, etc.
[0019] The filter unit 20 is preferably manufactured by means of printing technique and
particularly preferably manufactured by thick-film printing technique.
[0020] 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 substrate 11 or it may be alternately provided at
the upper and the lower surfaces thereof.
[0021] 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 the contact element 33. Further, in a filter function
in the filter unit 20, the upper electrode 14 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.
[0022] The leaf spring 31 may be of a material and/or construction having spring properties
or elastic properties 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.
[0023] 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.
[0024] 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(Mg
1/3Nb
2/3)O₃, Pb(Zn
1/3Nb
2/3)O₃, PbTiO₃ and Bi₂O₃.
[0025] The contact elements 33 are inserted respectively into the holes 21 formed in the
filter unit 20 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 contact 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.
[0026] 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 residue of flux for soldering is remained since the shield frame
32 and the filter unit 20 are not soldered. Further, the connector 30 is resistant
to temperature cycle.
[0027] 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 therefore not particularly limited.
[0028] Next, the electrical connector equipped with a filter according to the second invention
will be described in detail with reference to the preferred embodiments thereof as
illustrated in the drawings.
[0029] Fig. 4 is a perspective view showing a preferred 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 perspective views showing various contact elements with a stopper.
[0030] In the following description, the same features as those described in the first invention
with reference 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 identical with those in Figs. 1 to
3, are denoted by the identical reference numerals.
[0031] As shown in Figs. 4 to 7, the electrical connector 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 respectively 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.
[0032] Similar to the first invention, the leaf spring 31 is so contoured as to contact
with the ground electrode 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 interposed between the filter unit 20 and the shield frame 32 so as to
mechanically secure and hold the filter unit 20, the shield frame 32 and the body
34.
[0033] 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 interposed
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 stoppers 62.
[0034] As for the filter unit 20, the filter function 10 and the ground electrode 14, the
detailed description made with respect to the first invention is also appropriately
applied to the second invention.
[0035] 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 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.
[0036] As for the leaf spring 31, the detailed description made with respect to the first
invention is also appropriately applied to the second invention.
[0037] 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.
[0038] 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.
[0039] 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 elements 33 and the filter
unit 20 are not soldered, no cracks occur, which would otherwise occur by heat produced
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.
[0040] 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 examples.
[Example 1]
[0041] The electrical connector with a filter shown in Figs. 1 and 2 was made.
[0042] 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,
followed by firing for ten minutes at 850 °C to form the lower electrodes 12, 12'.
Then, a dielectric paste predominantly comprises Pb(Mg
1/3Nb
2/3)O₃ and Pb(Zn
1/3Nb
2/3)O₃ was screen-printed in such a manner as to have an overlaid portion on the lower
electrode 12, 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.
[0043] Then, the contact elements were inserted respectively 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.
[0044] Subsequently, the leaf spring 31 was inserted 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 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. 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]
[0045] The electrical connector with a filter shown in Fig. 3 was made.
[0046] 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 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 substantially same manner as in Example 1. In this manner, the
filter unit 20 was made.
[0047] 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 contact elements 33
were secured to the filter unit 20 by soldering from one side surface thereof, and
electrically connected to the lower electrode 12. Then, the flux was removed by ultrasonic
cleaning.
[0048] 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 electrically 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.
[Example 3]
[0049] The electrical connector with a filter shown in Figs. 4 and 5 was made.
[0050] First, the filter unit 20 having the filter function 10 and the ground electrode
was made in accordance with the substantially same manner as in the Example 1.
[0051] 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 connector with a filter without any application
of solder was made.
[0052] 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 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 temperature cycle and has a high reliability.
[Example 4]
[0053] The electrical connector with a filter shown in Figs. 6 and 7 was made.
[0054] First, the filter unit 20 having the filter function 10 and the ground electrode
was made in accordance with the substantially same manner as in the Example 1.
[0055] 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 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.
[0056] 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 simplified 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]
[0057] An electrical connector with a filter was made in accordance with the substantially
same manner as in 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.
[0058] Although the present invention has been described 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
[0059] The electrical connector with a filter according to the present invention not only
exhibits a high electromagnetic shielding effect but also a high attenuation 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 connector is resistant to temperature cycle and has high reliability.
Particularly, in the electrical connector with a filter according to the first invention,
electrical connection and mechanical holding can be realized simply by assembling
the shield frame, the leaf spring and the filter unit (and the body, where necessary)
and secured by set pins. Thus, the process can be 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.
1. An electrical connector with a filter comprising a shield frame, a filter unit having
holes, contact elements to be inserted respectively into said holes, and a leaf spring
interposed between said shield frame and said filter unit,
said filter unit having a filter function corresponding to said holes, and a ground
electrode;
said ground electrode and said shield frame being electrically connected by said
leaf spring; and
said filter unit and said shield frame being mechanically secured and held by said
leaf spring.
2. The electrical connector with a filter according to claim 1, wherein said filter unit
allows said contact elements to be inserted and secured therein.
3. The electrical connector with a filter according to claim 1, further comprising a
body, and said shield frame, said filter unit, said leaf spring and said body being
secured to one another.
4. The electrical connector with a filter according to claim 1, wherein said filter function
comprises a conductor and a dielectric substance and/or ferrite.
5. The electrical connector with a filter according to claim 4, wherein said dielectric
substance comprises at least one compound selected from the group consisting of Pb(Mg1/3Nb2/3)O₃, Pb(Zn1/3Nb2/3)O₃, PbTiO₃ and Bi₂O₃.
6. The electrical connector with a filter according to claim 1, wherein said leaf spring
is a plate, a spring, a wire, a rubber or a resin having spring properties or elastic
properties and electrically conductive properties.
7. An electrical connector with a filter comprising a shield frame, a filter unit having
holes, contact elements to be inserted respectively into said holes and each having
a stopper, a fixture for allowing said contact elements to be inserted, a leaf spring
interposed between said shield frame and said filter unit, and a body,
said filter unit having a filter function corresponding to said holes, and a ground
electrode;
said ground electrode and said shield frame being electrically connected by said
leaf spring;
said filter unit and said shield frame being mechanically secured and held by said
leaf spring; and
said contact elements being pressed against said filter unit by said fixture through
said stoppers.
8. The electrical connector with a filter according to claim 7, wherein said filter function
comprises a conductor and a dielectric substance and/or ferrite.
9. The electrical connector with a filter according to claim 8, wherein said dielectric
substance comprises at least one compound selected from the group consisting of Pb(Mg1/3Nb2/3)O₃, Pb(Zn1/3Nb2/3)O₃, PbTiO₃ and Bi₂O₃.
10. The electrical connector with a filter according to claim 7, wherein said leaf spring
is a plate, a spring, a wire, a rubber or a resin having spring properties or elastic
properties and electrically conductive properties.
11. The electrical connector with a filter according to claim 7, wherein said fixture
is a washer, a spring or a rubber.