KR100207304B1 - Electrical connector with tape filter - Google Patents

Abstract

An electrical connector assembly (10) includes at least one signal contact (22) and one grounding structure (16) mounted in a dielectric housing (12) having flat exterior surface portions (19). A filter (32) is associated with each signal contact, if desired, and is in tape form with dielectric material (36) laminated between broad area electrodes (34,38) with the tape attached to the housing exterior surface (14); the dielectric material is selected to have a dielectric constant and thickness to provide a desired capacitance between signal and ground electrodes (34,38). The method includes electrically joining the signal and ground electrodes to the signal contact (22) and grounding structure (16) while pressing the tape filter along and against the exterior housing surfaces (19) between the connections, for the electrodes (34,38) of the filter to be connected between the signal contact and ground structure to effectively insert the filter in the signal path to ground. <IMAGE>

Description

Electrical connector assembly and how to join a filter to its connector

1 is a perspective view of an electrical connector located on two typical tape filters of the present invention prior to assembly.

FIG. 2 is a view partially assembled of the elements of FIG.

3 is a partial side cross-sectional view of the end of the filter in which the end of the filter is connected to the contact of the connector.

4 is a perspective view of the connector of Figures 1 and 2 fully assembled.

5 is a perspective view showing the connection to the ground circuit of the connector and the end of the filter.

6 is a side view of the connector and filter of FIG.

7 is a side view of the connector immediately before complete assembly.

8 is a side view of the connector shown in FIG.

9 is a plan view of an alternative embodiment of a tape filter showing a pair of signal electrodes.

* Explanation of symbols for main parts of the drawings

10 connector assembly 12 connector

14: dielectric housing 18, 26, 28: post

22, 24: electrical contact 32, 32 ': filter element

34, 34 ': electrode 39, 39': finger

FIELD OF THE INVENTION The present invention relates to electrical appliances such as connectors, and more particularly to a method of assembling (assembling) tape filters to electrical appliances by mounting a laminated construction tape filter on the outer surface of the connector housing. will be.

The increasing use of high-speed digital pulses for communication has led to the use of sensitive components to receive and process these signals. This sensitivity, however, causes components to be vulnerable to undesired frequencies delivered over the same signal line as the desired signal frequency. To solve this problem, patents have emerged which aim to remove unwanted frequencies using electrical connectors as a means of accommodating suitable filters with suitable characteristics. US Pat. No. 4,695,115 relates to a telephone connector with a bypass capacitor, which uses a capacitor built into the connector to remove (i.e. filter) unwanted frequencies from the signal on the signal contacts of the connector. The filters here are referred to as tombstone capacitors, and means are provided for interconnecting the capacitors between the signal line and the ground (grounding) line. As you know, the filter accounts for a significant amount of the total volume of the connector.

US Pat. No. 4,772,224 shows a modular electrical connector that provides filtering, including a ferrite inductor with a capacitor. Like US Pat. No. 4,695,115 the filter element occupies a significant part of the volume of the device, especially in terms of the height of the device from the printed circuit board or part of the assembly provided with the connector to be filtered.

Accordingly, it is an object of the present invention to provide a connector having a filter which minimizes the package area of the connector, and another object of the present invention is an unobstructed method which generally matches the shape of the outer surface on the outer surface of the connector housing. It is an object of the present invention to provide an assembly of a multi-pin electrical connector connected with a thin tape filter disposed in a vacuum. It is a further object of the present invention to provide a simple and easily manufacturable filter arrangement suitable for use in connectors or for other electrical appliances such as printed circuit boards and transmission cables.

According to the present invention, there is provided a filter assembly having at least one thin film (foil) signal electrode and at least one ground electrode, wherein the electrodes are separated by a thin coating of a dielectric material on the electrode region, the dielectric constant of the material and the electrode Intervals, etc., are selected to provide a capacitance that effectively removes unwanted frequency components and allows the desired frequency components to pass through the signal transmission circuit. Unwanted frequency components are connected to the grounding means and grounded by the filter. The filter includes a dielectric material laminated with the electrode and additionally includes a thin dielectric film that is used as a carrier to hold the electrode and the dielectric material in position for fabricating and processing the assembly.

In one embodiment of the present invention, the above-mentioned object can be achieved by using an electrical connector with a plastic housing having a conventionally shaped outer surface. The connector includes a signal connection and a grounding contact accompanying the housing having a post portion extending from the bottom of the housing, and includes a shield structure on the front or mating surface of the connector, the post portion being the bottom of the connector or It extends downward from the mounting surface and is inserted into each hole of the printed circuit board of the circuit assembly and soldered (soldered) to the circuit assembly. The signal transmitted to the connector by the mating connector is transmitted to the signal trace on the circuit assembly through a printed circuit board conductive trace extending from the connection with the contact at the opening by the signal contact, and receiving and using the signal for communication. Delivered to the parts within. Such a coupling arrangement is described in US Patent Application No. 07 / 971,028 filed November 3, 1992.

In combination with a connector, which can be in the form of a telephone receptacle that engages a telephone connector plug, the filter's signal and ground electrodes have holes that fit into connectors and contacts that are properly terminated, such as solder joints, and the filter Filter tape lamination is folded from the bottom of the connector housing over the back and top of the housing, and the grounding electrode is coupled to the shielding and grounding of the connector by soldering. The electrode layer except for the soldering portion is sprayed with a polymer coating or laminated to a polymer film to provide an insulating layer.

The present invention applies to a wide range of connectors, comprising at least one signal contact and at least one grounding contact, having a separate tape structure or a separate signal structure for the separated signal contacts depending on the size of the capacitor required It has a common ground and separate electrodes for the contacts. The present invention also shows laminations with separate signal and common grounding electrodes for filter capacitors in some applications. The filter of the invention, referred to as a tape-shaped laminate, in any case, is made very thin and flexible so that it can be covered on a substantially flat portion of the outer surface of the connector housing and fixed by the adhesive or bonding or on the housing. Secured by a structure to allow the connector / filter assembly to be treated as one part. The filter tape is mechanically fixed to the connector housing by solder joints with the signal and ground contacts of the connector, optionally further secured by a plastic covering which is assembled to the connector after soldering. Through this technique, the volume change caused by adding a filter can be minimized, and the present invention can be applied to existing connector designs by adding a simple assembly technique.

The filter of the present invention can also be used in other electrical appliances such as printed circuit boards, where the signal and ground electrodes can be soldered directly to the exposed contact pads of the signal and ground traces, for example. The filter may be used around a shielded signal transmission cable.

The method of the present invention comprises providing a tape filter for a particular selected connector, electrically connecting each signal electrode to a corresponding signal terminal portion of the connector extending from the connector housing or at least exposed along the surface of the housing; Wrapping the tape filter along the outer surface of the connector to be disposed proximate the connector surface, and electrically connecting each ground electrode with a ground cell or shield of the connector.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, an electrical appliance, such as the connector assembly 10 shown, includes a connector 12 and a pair of filters 32 and 32 ', where the connectors and filters are before assembly. This connector 12 may be a known type of modular telephone receptacle jack mountable to a printed circuit board (not shown) at the board connection or mounting surface 25. The connector enters the pupil at mating surface 29 and a modular telephone plug (not shown) connected to the telephone cable interconnects the cable with signals sent to the circuit board, telephone receiver, facsimile receiver and / or computer via the connector. Let's do it. Signals transmitted to circuits through plug and jack connectors often carry unwanted frequencies through radiation, induction, and leakage of fields from other circuits. These unwanted frequency components may cause errors, particularly in the interpretation of digital 1 and 0, which constitute digital transmission. The object of the present invention is to remove these unwanted frequencies (filter out) and at the same time provide the proper signal display, i.e. The frequency constituting the voltage level is intended to pass through the connector to enter circuits and devices that receive the signal.

The construction of the connector 12 is relatively well known, with sealing and grounding comprising posts 18 extending from the bottom of the connector as shown in FIGS. 1 and 2 for connection to the circuit of the board. Plastic housing 14 having structure 16 on its surface. The housing 14 includes a series of grooves 20 extending through the rear protrusion selected from the top. The groove 20 contains a set of signal contacts 22 and 24 that are offset as shown in FIG. 1, which contacts are terminated at the posts 26, 28 and the posts 28, 26 are mounted on the bottom surface or mounting. It extends below face 25 and is terminated at the conductive traces of the substrate along the grounding post 18 of the shield 16. The front ends (not shown) of the contacts 22 and 24 are formed to extend into the plug-receiving pupil of the mating surface 29 to accommodate the contact portion of the mating plug connector connected to the signal cable. The housing 14 includes a resilient mounting fastener 30 extending from the bottom or mounting surface 25 of the connector, which is plugged into a corresponding opening in the circuit board on which the connector acts. Fasteners 30 are shown in more detail in FIGS. 6-8, which include an inner slot and barb edges 31, which barb posts 18, 26 and 28 to the substrate. Hook the connector housing 12 to the board before soldering.

Sealing structure 16 includes opposing side portions 15 and portions 17 thereon, as shown in FIGS. 1, 2, 4 and 5 degrees. It is folded down with respect to the upper surface of the housing 12 as shown in FIG. As can be seen from some figures, the housing 12 has an outer surface consisting of an upper portion, a rear portion, a side portion, and a lower portion. The upper and side portions have a relatively flat plane, and the rear portion also has a flat surface and relief portions as shown in some figures.

In accordance with the invention, the illustrated filters are for two of the six signal contacts, which are equipped with two filter elements 32, 32 ′; All six signal conductors can be filtered according to the method described below. As can be seen in FIG. 1, the filter element 32 comprises an upper electrode 34 and a lower electrode 38. In between, a substrate of dielectric material 36 is provided as shown in FIG. At the front end of the element 32 is a finger 35 of an upper electrode 34 defining a signal connection, which has an opening, like 37, which is inserted therein and shown in FIG. It is aligned to receive an inner post 28 which is soldered (soldered) by one solder fillet S. On the back side there is a grounding finger 39 of the lower electrode 38 which defines a ground connection which is soldered to ground the sealing structure 16 during final assembly. The posts 26, 28 defining the signal connection positions are spaced apart from one another, and the top 17 of the shield 16 defining the ground connection position is spaced apart from all signal connection positions. The fingers 35 are laterally staggered or electrically separated from the other filter element 32 'so as to be spaced apart without engaging the posts 26 extending to terminate on the electrodes 34' of the element 32 '. . Element 32 'also includes a grounding finger 39'.

Each filter element has upper and lower electrodes 34 and 38 separated by a substrate 36 of dielectric material. The device is first formed by laminating each layer of conductive material on each surface of a sheet of dielectric material and then defining the boundary of each electrode by an etching process, and by forming a plurality of tape filters during the etching process. Can be. After etching, the outer surface of the electrode is preferably sprayed with polymer paint or laminated with a polymer film except for the soldering position of the electrode to have an insulating covering. Individual electrodes 34, 34 ′ are for each signal contact associated with one post 28 and the other is for each signal contact associated with post 26, with common grounding electrodes 38, 38. '), Having an area selected in relation to a specific dielectric material having a specific dielectric constant and thickness of the coating 36 to provide the desired capacitance associated with each signal contact, and inherently capacitive (capacitance) Connect to ground through the material. As is well known, capacitance is a function of the area of the electrode, the dielectric constant of the dielectric, and the spacing between the electrodes, the capacitance value decreases as the spacing between the electrodes increases and increases as the dielectric value increases.

According to one embodiment of the invention, the electrode is formed from a foil (thin film) of about 0.0014 inches thick, and the substrate is about 0.002 inches thick, so that the package formed is about 0.005 inches thick. As a dielectric material, Rohm and Haas Inc., Philadelphia, PA, with a matrix of acrylic polymer with a particle size of about 1 micron and a barium titanate filler uniformly distributed by about 50 percent by weight. Polymeric films such as PHEOPLEX LC 40 acrylic emulsifiers available from Rohm and Hass, Inc. are used. The conductive layer is made of 1/2 ounce copper bonded to a sheet of dielectric material using a 3-ply heated and pressurized laminating machine.

The resulting laminations are known to have capacitances that vary between 400 and 480 pico farads when the individual electrodes are 0.200 inches wide and 1 inch long. These capacitances begin with insertion losses of a few dB at slightly less than 10 MHz and rise to around 12 to 15 dB near 100 MHz and provide attenuation that shows a peak of about 34 dB around 250 MHz for 400 picofarad capacitances. The 480 picofarad sample has an insertion loss slightly less than 30 dB at frequencies around 200-300 MHz. The use of an appropriate amount of barium titanate in the polymer can withstand voltages above 1000 volts, which may meet FCC requirements.

Alternatively, lamination to a sheet of barium titanate-filled polymer using a pair of opposing foils made of electrolyzed aluminum; Or screen printing or spraying a coating of barium titanate-filled polymer onto one sheet of foil and laminating the other foil sheet there; After appropriate masking, the sheet of foil is etched in a conventional manner to produce a structure similar to that of the etched electrode structure as described above, and then sold by Mavidon Corp., Palm City, Florida. A dielectric coating, such as 350 CC epoxy, may be applied to one or both electrode outer surfaces. The tape filter can now be cut from the sheet of dielectric material.

Between the filters 32 and 32 'is laminated a thin insulating film (not shown) that electrically insulates the electrode 34' and the electrode 38, as shown in FIG. In the post portions 26 and 28 are soldered to the respective contacts 22 and 24. This lamination, as shown in FIG. 7, rises from the bottom of the connector housing 14 to the backside and is placed on its flat surface and crosses the grooves 20 and 18 shown in FIGS. 1 and 2 across the top. By crossing and being placed between the raised lip 41 of the housing 12, it prevents failure of the side edges and prevents the filter from moving or pressing the solder termination joint. The signal connections defined by fingers 35 and 35 'are staggered with respect to each other and connected to respective signal connection positions (posts 26 and 28); The shape of the filter elements 32, 32 ′ so that the ground connections defined by the fingers 39, 39 ′ are staggered with respect to each other and adjacent to the ground connection positions defined by the upper portion 17 of the shield 16. And the size is determined.

At the ends of the elements 32 and 32 'which are folded relative to the top surface, the protrusions 17 are folded over the tops of the fingers 39 and 39' of the filter as shown in FIGS. As shown in FIG. 5, the solder pellet S 'connects the finger 39 of the electrode 38 to the protrusion 17 and thus to the sealing structure 16 and the fillet solder S connects the finger 39'. It is connected to the electrode 38 'of the element 32' and to the same grounding structure. In the same way the two filter elements 32 and 32 'are folded and terminated in the grounding structure as shown. After soldering, it is preferable to mold (mold) the plastic covering thereon to protect the filter tape, or to fix the pre-molded plastic cover to the connector on the filter tape in a conventional manner.

In the present invention, there is also shown an element such as (32) which is grounded separately instead of commonly grounded (grounded) as shown, and suitably terminated using fingers such as (39 and 39 '). In the present invention, it is also possible to increase the area of the electrode, such as electrode 34, for a given signal contact if necessary to obtain the desired capacitance, and ancillary elements can be provided for the remaining signal electrodes. It is also possible to use an additional area obtained by providing an electrode 40 extending over the side of the housing, as shown by the dashed line in FIG. 8, which increases the capacitance of the device.

In the present invention, one signal contact and one ground contact may be used, or two, four, or six contacts may be used. For example, FIG. 9 shows an alternative embodiment of a tape filter in which two contacts are applied to the filter by one tape structure. The tape filter 80 is shown having two signal electrodes 82 and 84 separated by a gap 86 on the common side of the dielectric structure. One common ground electrode 88 is disposed along the opposite surface of the substrate. Each signal electrode 82, 84 has a respective finger 90, 92 extending across the axis of the corresponding signal terminal of the connector (not shown), the terminal having a respective hole through the fingers 90, 92. (94, 96) and are soldered (assembled) when the tape filter is assembled (assembled) to the connector. The ground electrode 88 includes a grounding finger 98 that extends below the extension of the signal electrodes 82 and 84 for soldering to the ground shield of the connector (not shown).

Various designs can be made to properly use each part of the outer region of the housing to achieve the desired capacitance. As described above, preferred embodiments of the present invention can be realized, and the present invention is defined by the appended claims.

Claims (8)

A dielectric housing having a fixed electrical contact and comprising a post extending outwardly from the mounting surface, the electrical housing having a shield member mounted on the housing and a filter element electrically connected to at least one of the posts; In a connector assembly, the filter element comprises an electrode separated by a dielectric material, one of the electrodes is electrically connected to one of the posts, and the filter element extends along a portion of the dielectric housing to And an electrical connector assembly electrically connected to the shield member. The filter element comprises a contact finger electrically connected to the post. 3. The electrical connector assembly of claim 1 or 2, wherein the filter element comprises a ground finger electrically connected to the shield member. 2. The electrical connector assembly of claim 1, wherein the shield member has a top that bends to engage the housing. 5. An electrical connector assembly according to claim 1, 2 or 4, wherein the housing has a flat surface along its rear surface and top, and wherein said filter element extends along said flat surface. At least one signal contact member having a first and a second surface and having first and second contacts exposed to the first and second surfaces, respectively, for defining a signal transmission circuit between corresponding conductors for signal transmission Coupling a filter element to an electrical appliance of a known construction and appearance type having a dielectric housing having a grounding means, the grounding means having at least partially exposed portions along an outer surface of the housing away from the first surface Providing a filter element for each of said signal contacts of said electrical appliance having at least one signal electrode for connecting to said respective signal transmission circuit and a ground electrode for connecting to grounding means; Wherein the filter is disposed electrodeically between the electrodes and has unwanted frequency components from the signal transmission circuit. Is defined by a dielectric material having a characteristic of transmitting to the grounding means, the filter has a thin and flat configuration and has sufficient flexibility to be formed into a selected shape, and also the exposed surface of the first and the grounding means. Has a two-dimensional shape selected to correspond to an outer surface portion of the electrical appliance extending between the portions; Connecting the signal electrode adjacent to the first region of the filter element with an exposed portion of each of the signal contacts; Pressing the filter member along the outer surface portion of the housing of the electrical appliance; Connecting the ground electrode adjacent to the second region of the filter element remote from the first region to an exposed portion of the grounding means; The filter element extends over the flat surface portion at least in part to conform to the shape of the outer surface of the electrical appliance comprising the signal transmission circuit, thereby filtering the volume of the filter element / electrical assembly without changing the existing electrical appliance. Filter element coupling method characterized in that to minimize. The method of claim 6, wherein the connecting step includes a soldering process. 8. A method as claimed in claim 6 or 7, wherein the exposed portion of the grounding means is bent to engage the housing after the ground electrode is connected to the exposed portion.