JPS59184479A - Filter connector - Google Patents

Abstract

A filter connector (8) for attentuating electromagnetic interference up to 1000 MHz having a housing (10), a filter element (16) enclosed within the housing (10) and electrically conductive pins (18) mounted within the filter element (16). The filter element (16) contains an alumina substrate (42) with thick film layers (44, 50) of a metallization forming pin and ground electrodes, and a dielectric layer (46, 48) separating the electrodes screen printed over the substrate and a glass encapsulant (52, 54). The ground electrode (44) substantially covers a horizontal surface of the substrate (42).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to filter connectors for reducing electromagnetic disturbances in electrical devices, and more particularly, each housing a conductive pin and having various frequencies applied to the conductive pin. The present invention relates to a filter connector having a series of thick film capacitors with holes inside the various elements to attenuate.

Filter connectors for attenuating high frequency interference from electrical equipment are disclosed in several patents, such as U.S. Pat.
No. 464, No. 4,126,840, No. 4,144
, 509 and 4.18'7,481. In each of these U.S. patents, the capacitor used with the filter consists of a series of capacitors forming a monolithic structure. It is a ceramic layer.

Thick film capacitors are also well known from US Pat. No. 4,274,124. Although monolithic capacitors are currently used in filter connectors, U.S. Pat.
Substitution of the thick film capacitors shown in '74,124 has not previously been practiced. Problems have arisen in designing thick film capacitors for filter connectors with sufficiently low inductance to attenuate high frequencies.

In recent years, the proliferation of computers, especially home computers, has generated significant additional high frequency electromagnetic signals that can interfere with other electrical equipment. For the purpose of reducing the output of such signals, the United States Federal Communications Commission (FCC)
) rules requiring attenuation at the source (47 CFR
15°5ubpart J) was distributed.

Commercially available monolithic capacitor structures used in filters are not cost effective for use in low cost electronic devices such as personal computers.

Since the cost of manufacturing filter connectors can be significantly reduced through the use of thick film capacitors, filter connectors such as thick film capacitors with such low inductance are needed. Useful commercial filters attenuate electromagnetic signals to at least 30 decibels (dB) at frequencies of 1000 megahertz (MHz).

The present invention is a cost effective electrical filter connector for filtering broadband frequencies up to 100,100 ohms using a specific design of thick film capacitors in a repeating sequence to form the filter element. The filter element includes a number of closely spaced thick film capacitors each having a conductive pin mounted in its hole. This capacitor has multiple layers of material screen printed over an alumina substrate that has two horizontal planes and is generally rectangular in shape. One layer is the metallization that forms the ground electrode.
totalization). This electrode is grounded to the connector housing. The electrode substantially covers the entire horizontal surface of the alumina substrate and has a hole of sufficient size to accommodate the conductive pins without contacting any of the pins.

Another layer is the metallization forming the pin electrode, but its area is limited to a portion around a given hole in the substrate. This layer is in electrical contact with the pins via solder joints. Between these two electrodes,
There is a dielectric layer applied directly to one of the electrodes. This layer substantially overlaps the horizontal plane of the ground electrode when it is the first layer and exposes the two longest edges on each side of the ground electrode.

This layer also has holes just barely large enough to pass conductive pins through them without contacting the dielectric material. It's covered.

The fourth and final layer is a non-conductive encapsulant to exclude moisture covering all layers except the contact areas or solder areas. This filter connector is capable of maintaining substantial attenuation in the very high frequency range up to at least 1 DOOMHz.

The present invention will be best understood by those skilled in the art by reference to the following detailed description taken in conjunction with the accompanying drawings.

Referring first to FIG. 1, filter connector 8 includes a top shell 10 having a top shell 12 and a bottom shell 14. As shown in FIG. The housing 10 surrounds two rows of pins 18 attached to the filter member 16. Inside the connector 8 are a top insulator 20 and a bottom insulator 38.
protected by. The pin 18 is attached to the solder joint 22.
) ”57 'l #7斐16 L(@ h Vc
*Ni-"6. A threaded insert 28 can optionally be attached to the connector as a fitting for the cabinet. The grounding contact 62 is inserted into the pin 18 and is inserted into the socket of a trial plug (not shown). The top/el 12 can be used to form a grounding point. The two shells 12 and 14 are crimped together by tabs 40. Pin 18 is shown in FIGS. 1-6. It can be straight, as shown, or it can be formed at right angles, as shown at 34.

2-4 illustrate the solder joint 22 when the pin 18 is attached to the filter element 16. Hole 31 in bottom insulator 68 provides a bottom outlet for the reservoir of pin 18. Hole 60 in filter element 16 provides a means for passing pin 18 through the filter member and locates solder joint 22.

The structure of filter element 16 may be understood with reference to FIGS. 4 and 5. FIG. 4 shows only one of the condenser units within filter element 16 for illustrative purposes. Filter element 16 includes an alumina substrate 42 . .

A metallization 44 is screen printed on one horizontal surface of the alumina substrate 42.

This metallization 44 forms a ground electrode that is then welded to shell 14 with solder 66. This grounding electrode 44 substantially covers the entire surface of the alumina substrate 42 . The grounding electrode 44 has a hole 24 large enough to accommodate the pin 1B without contacting the pin 1B, as seen in FIG.

Ground electrode 44 is partially covered by a screen printed layer of dielectric 46. Although this specification refers to a single layer of dielectric for purposes of illustration, in practice two layers of dielectric 46 and 48 are used to provide more than sufficient protection against interelectrode Q-shorts. It is screen printed on the grounding electrode 44. The dielectric layer 46/4B also fills the dog hole 26 slightly less than the diameter of the pin 18, as seen in FIG. A layer of dielectric 46/48 covers the horizontal surface of ground electrode 44 except for edges 46 and 45. Edges 46.degree. 45 are the areas used to solder the ground electrode 44 to the shell 14. A layer of insulator 46748 is also applied to the vertical edge of ground electrode 44 adjacent hole 24 as seen in FIG.

A second metallization 50 is intermittently screen printed onto the dielectric layer 48 in a regular pattern, typically in the shape of an arrowhead. This forms a series of bin electrodes 50.

Each of the pin electrodes 5D is connected to the pin 18 via the solder joint 22.
is in electrical contact with. This pin electrode 50 is connected to the dielectric layer 46/48 as seen in FIGS. 5 and 6.
screen printed to form a series of individual spaced arrowhead-shaped layers distributed over the surface of the substrate. One electrode 50 is adjacent to each hole 26 and annularly surrounds hole 41. The uppermost layer, ie, the encapsulated molded glass 52154, is the electrode 50 and the dielectric layer 46.
/48 are both covered. Although only one layer is shown in FIG. 5, in reality two layers of glass encapsulant are usually screen printed onto the i[1isD to increase security. For purposes of this specification, when referring to a layer of encapsulant, one or more layers of encapsulant are meant. The arrowhead-shaped design of electrode 50 allows the capacitors used in the filter connector to be closely spaced;
Therefore, it is possible to construct a device that increases the area and therefore the capacitance value of the capacitor. Of course, other designs could be used that would satisfy the purpose of manufacturing capacitors of the type used in the present invention.

The metallization used in the first and third layers is preferably formed of a noble metal or an alloy of noble metals.

However, copper metallization compositions could also be used.

Particular preference is given to metallizations of palladium-silver alloys. Each layer is applied using conventional screen printing methods. The dielectric used may be of any type commonly used in capacitors. However, barium titanate is preferred.

The glass encapsulant can be of any type used in capacitors having a coefficient of expansion compatible with the other components used.

As understood from FIG. 8, the ferrite sleeve 19
can be attached to pin 18. Such sleeves are well known, as seen from US Pat. No. 4,144,509. The use of certain filter elements of the present invention increases the filtering action of filter connectors that use ferrite.

The hexametallization used in the present invention consists of a composition containing metal fines of noble metal or copper, a binder for the metal, and a vehicle for uniformly dispersing the metal fines.

The composition is applied by a screen printing process and the vehicle is removed from the applied composition by baking the screen printed composition onto the layer by conventional techniques.

Although FIGS. 4 and 5 show a ground electrode applied as a layer of first metallization and a pin electrode 50 applied as a layer of third metallization, this can be reversed. Therefore, the pin electrode 50 connects directly to the alumina 42 around each hole 41.
+ Can be printed. Next, a layer of dielectric 46
and 48 are applied overlapping the electrode layer 50 excluding the solder areas 22. A grounding electrode 44 is then screen printed onto the dielectric layers 46 and 48 and all exposed horizontal surfaces of the alumina substrate 42.

Mounting medium 52154 is applied in the same manner as in FIG.

Encapsulant 52154 covers all exposed surfaces except for edges 4 and 45, which are the soldering areas.

The low inductance at high frequencies obtained with the present invention is a direct result of the shape of the ground electrode in conjunction with the pin electrode. If the grounding electrode and dielectric were placed on only one side of the pin, we would have the attenuation curve (, ) of FIG. This decay curve is especially true at 200 M
Above H2, and more particularly above 700 MH2, the superhigh-rises show a reduced attenuation curve in the region and thus a reduced filtering effect. The reason for this reduction in attenuation is that the capacitor is experiencing a series of resonances near the 2DOMI (Z) generated by the inductance of its electrodes (indicated by the button peak in attenuation curve (a)). .

If the grounding electrode extends substantially over the entire substrate and the dielectric surrounds the hole, the current from the pin can be split into two components, each component connected to the ground connection on each side of the filter element 16. flowing towards. As a result, the effective inductance of the stain pole is reduced by providing two parallel current paths. This reduction in inductance results in a series of increases in the resonant frequency and curve (b) in Figure 9.
This results in an increase in attenuation as shown in .

[Brief explanation of the drawing]

1 is an isometric view, partially in section, of the filter connector assembly; FIG. 2 is a partial elevational view, partially in section; and FIG. 6-6; FIG. 4 is a cross-sectional view of a single capacitor unit of the filter element combined with a bottle; FIG. 6 is a perspective view of the filter element shown in FIG. 5, and FIG. 7 is an exploded view of the filter element shown in FIG.
Figure 8 is a partial cross-sectional view of a filter connector with a ferrite sleeve on each bottle holder, and Figure 9 is an enlarged cross-sectional view taken along line -7.
8 is a graph showing an attenuation curve of a filter connector when the base body shown in FIGS. 7 to 8 is not covered, in comparison with the base body shown in FIGS. 8... Filter connector, 10... Housing, 1
2...Top shell, 14...Bottom shell, 16...
・Filter element, 18... Pin, 20... Top insulator, 22... Solder joint, 24. 26... Hole, 28
... insert, 30 ... hole, 32 ... grounding contact, 68 ... bottom insulator, 41 ... hole, 42 ...
Alumina substrate, 44...Metallization, 43.
45...edge, 46.48...dielectric, 50...
Electrode, 52.54...Glass mounting medium. 1 day ＼ 3 lectures per day 000QOOO Scary appearance

Claims (1)

Claims: 1) An electrical filter connector for attenuating electromagnetic interference, comprising: a housing; a filter element enclosed within the housing; and a conductive pin mounted within the filter element. The filter element has two flat horizontal surfaces with holes and a plurality of adjacent adjacent surfaces formed by screen printing multiple layers on an alumina substrate fitted with conductive pins. thick film capacitors spaced apart from each other, one layer of said multilayer forming a grounding electrode in electrical contact with said connector housing and substantially covering one horizontal surface of said substrate and said grounding electrode; The inside of the grounding electrode must have a hole with a diameter large enough to allow the conductive pin to pass through it without touching the grounding electrode! An electrical filter connector characterized by: 2) the electrode layer is the first layer applied to the substrate;
a second layer is an insulating dielectric material applied over the grounding electrode at least in the area surrounding each substrate hole excluding the electrical contact areas; and a third layer surrounding each substrate hole. A thick film metallization forming individual pin electrodes applied on top of the second layer in the regions, thereby making electrical contact with the pins and insulating them from the grounding electrodes. A filter connector according to scope 1. 3) The scope of the patent d blue water described in paragraph 2, characterized in that the fourth layer is a non-conductive encapsulant with a matched coefficient of expansion covering all exposed layers except the electrical contact areas. filter connector. 4) A filter connector according to claim 3, characterized in that the first layer of the filter element is a precious metal metallization. 5) A filter connector according to claim 3, characterized in that the first layer of the filter element is a palladium-silver alloy metallization. 6) Filter connector according to claim 6, characterized in that the third layer of the filter element is a precious metal metallization. 7) Filter connector according to claim 6, characterized in that the third layer of the filter element is a palladium-silver alloy metallization. 8) A filter connector according to claim 6, characterized in that the first layer of the filter element is a copper metallization. 9) Filter connector according to claim 3, characterized in that the third layer of the filter element is a copper metallization. 10) A filter connector according to claim 2, characterized in that the third layer metallization is formed in the shape of an arrowhead. 11) A filter connector according to claim 1, characterized in that a ferrite sleeve surrounds each conductive pin. 12) An electrical filter connector for attenuating electromagnetic interference comprising a housing, a filter element enclosed within the housing, and a conductive pin mounted within the filter element, the filter element comprising: a housing; comprises a plurality of closely spaced thick film capacitors, each thick film capacitor encasing a pin within a hole in an alumina substrate having two flat horizontal surfaces and screen printing on said substrate. a metallization of a noble metal forming an electrode grounded to the connector housing and substantially covering one horizontal surface of the substrate; a layer having a diameter sufficiently large to allow the conductive pin to pass through the pin without contacting the first layer; a second layer is a dielectric insulating material; and the second layer is an outer electrical contact. a third layer substantially covering the first layer except for the area and overlapping the first layer annularly around each hole, the third layer forming an individual pin electrode surrounding each respective substrate hole; The second layer is applied in an annular overlapping manner, and the fourth layer has a coefficient of expansion compatible with the other layers along with the substrate, and all exposed layers except the electrical contact areas. An electrical filter connector characterized by a non-conductive encapsulant enclosing the filter. 13) The filter connector of claim 12, wherein the pin electrode metallization extends into and adheres to each substrate hole. 14) said grounding electrode is a second layer and a third layer applied over substantially all horizontal surfaces of said substrate, the first layer surrounding each substrate hole; Claim 1, characterized in that it is a metallization forming individual pin electrodes applied on the substrate, and the second layer is a dielectric material applied on each pin electrode. Filter connectors listed. 15) The fourth layer is an electrically non-conductive encapsulant having a coefficient of expansion compatible with the other layers along with the substrate and covering all exposed layers except the electrical contact areas. The filter connector according to item 14. 16) Claim 15, characterized in that the first layer of the filter element is a precious metal metallization.
Filter connectors as described in section. 17) A filter connector according to claim 15, characterized in that the first layer of the filter element is a palladium-silver alloy metallization. 18) Claim 15, characterized in that the third layer of the filter element is a precious metal metallization.
Filter connectors as described in section. 19) The filter according to claim 15, characterized in that the third layer of the filter element is a palladium-silver alloy metallization.20) The first layer of the filter element is a copper metallization. 16. The filter connector according to claim 15, characterized in that it is a lization. 21) A filter connector according to claim 15, characterized in that the third node of the filter element is a copper metallization. 22) Claim 14, characterized in that the metallization of the first layer is formed in the shape of an arrowhead.
Filter connectors as described in section. 23) An electrical filter connector for attenuating electromagnetic interference having a housing, a filter element enclosed within the housing, and a conductive pin mounted within the filter element, the filter element comprising: A plurality of closely spaced thick film capacitors, each capacitor having a pin housed within a hole in an alumina substrate having two flat horizontal surfaces, and having a polygon screen printed on the substrate. having overlapping layers, the first layer being a precious metal metallization forming individual pin electrodes applied on the substrate around and within each hole, said first layer being threaded through the holes in said substrate. a dielectric insulating material in electrical contact with the conductive pin, the second layer overlapping the first layer excluding the electrical contact area, the third layer forming a grounding electrode and the second layer and a metallization of a precious metal overlapping substantially all of one horizontal surface of said substrate, and a fourth layer having a coefficient of expansion compatible with the other layers of the substrate and providing electrical contact areas; An electrical filter connector characterized by a non-conductive encapsulant covering all but all exposed layers. 24) The filter connector of claim 23, wherein the pin electrode metallization extends into and adheres to each substrate hole. 25) The filter connector according to claim 1, wherein a grounding electrode and a conductive housing are electrically connected on one horizontal surface of the base.