US 3538464 A
Description (OCR text may contain errors)
J. J. WALSH MULTIPLE PIN CONNECTOR HAVING FERRITE CORE STACKED CAPACITOR FILTER Original Filed Sept. 12, 1966 Nov. 3, 1970 I: 1 kw ATTORNEY United States Patent 3,538,464 MULTIPLE PIN CONNECTOR HAVING FERRITE CORE STACKED CAPACITOR FILTER James J. Walsh, Erie, Pa., assignor to Erie Technological Products, Inc., Erie, Pa., a corporation of Pennsylvania Continuation-impart of applications Ser. No. 306,406 and Ser. No. 306,407, both filed Aug. 20, 1963, now Patent Nos. 3,275,954 and 3,275,953, which is a continuation of applications Ser. No. 578,577, Sept. 12, 1966, and Ser. No. 805,099, Feb. 18, 1969, both now abandoned. This application Oct. 13, 1969, Ser. No.
Int. Cl. H01h 7/14; H01g /01 US. Cl. 333-79 12 Claims ABSTRACT OF THE DISCLOSURE This application is a continuation in part of applications Ser. No. 306,406 and Ser. No. 306,407, now Pats. 3,275,954 and 3,275,953 and a continuation of applications Ser. No. 578,577, filed Sept. 12, 1966, abandoned, and Ser. No. 805,099, filed Feb. 18, 1969, now abandoned.
This invention improves the combined connector and filter assembly by sandwiching a multiple capacitor laminate or monolith between the parts of the connector housing. This permits a reduction in size due to the compact construction provided by the laminate. In a preferred form, there are several capacitor laminates alternating with ferrite plates to provide a filter of the desired number of stages.
In the drawing, FIG. 1 is an elevation of a connector, partly broken away, FIG. 2 is an exploded view of one of the capacitor laminates used in the connector, and FIG. 3 is a section through a preferred form of filter having a ferrite plate sandwiched between two capacitor laminates.
The connector shown in FIG. 1 has a plurality of pins, each representing a circuit. The male connector is shown in FIG. 1. The female counterpart is of conventional design. The term pin is used to designate either a male or a female connector.
The connector has a metallic housing 1 suitably supporting members 2 and 3- of insulating material bolted or otherwise fastened together. The members 2, 3 have aligned sockets 4, 5 each associated with a pin 6. In the bottoms 7, 8 of the sockets are aligned clearance openings 9, 10 which provide clearance so the pins can float to facilitate insertion and removal. The pins are provided with thrust collars 11, 12 respectively larger than the openings 9, 10. The collar '11 may be integral with the pin 6 and the collar 12 may be suitably fastened to the pm.
In order to reduce radio frequency interference, there is sandwiched between the parts 2 and 3 a filter assembly comprising upper and lower multiple capacitor laminates 13, 14 and an intermediate ferrite plate 15 held together by the peripheral metal band 16 which serves as the ground terminal for the filter assembly and is usually electrically connected (for example, by spring contact 116a) to the metallic housing 1.
3,538,464 Patented Nov. 3, 1970 "ice In a preferred form, the multiple capacitor laminates 13 and 14 are of similar construction and comprise a plurality of films of green ceramic from 2-3 mils thick suitably electroded and stacked one on top of the other and fired into a unitary ceramic body in which the films coalesce to form a sealed unitary structure. The dielectric films are too thin to be illustrated in FIG. 1 and are, accordingly, illustrated in FIGS. 2 and 3.
The particular multiple capacitor laminate shown in FIGS. 2 and 3 comprises four films 17, 18, 19, 20, although obviously a different number of films could be used. As will be explained hereafter, film 18 carries a ground electrode and films 17 and 19 carry live electrodes in capacity relation to the ground electrode. Less capacity may be obtained by omitting the film 17. More capacity may be obtained by adding another film 18 below the film 17 or by further stacking in alternating relation additional films carrying ground and live electrodes in accordance with the principles of multiple electrode capacitors. These films are made of suitable dielectric ceramic, for example, one of the titanates, and have a thickness of from 2-3 mils, although thicker films may be used for higher voltage applications. The film 117 has on its upper surface a plurality of metal paint live electrodes 21, each extending to the edge of a hole 22 in alignment with the pin 6 and spaced from each other so as to be electrically separate. Between adjacent electrodes 21 is a grid electrode 23 which is spaced from the electrodes 21. The grid electrode 23 extends to the outer edge of the film 17. The purpose of the grid electrode 23 is to provide a ground potential between adjacent electrodes 21 to eliminate cross-coupling between adjacent electrodes. The electrode 23 may be omitted if its function is not desired. The film 19 is a duplicate of film 17 and corresponding parts are indicated by the same reference numerals. The film 18 has on its upper surface a metal paint ground electrode 24 extending over the entire upper surface except for margins 25 about holes 26 which register with the holes 22 in the films 17 and 19. Each of the electrodes 21 of the films 17 and 19 (the live electrodes) is in capacity relation to the ground electrode 24 of the film 18. The film 20 has on its upper surface a plurality of metallized coatings 27, each encircling one of the holes 28 which register with the holes 22 and 26 in the other films. The purpose of the coatings 27 is for making electrical connection to the pins and to the live electrodes 21, for example, by flexible conductive rubber sleeves 29 or other connection. Around the periphery of the film 20 is a metallized border 30 by which a soldered connection 31 may be made to a flange 32 on the metal band or ground terminal 16.
In the manufacture of the multiple capacitor laminate, the electrodes 21, 23, 24 are applied to the green ceramic in the form of a high temperature metal paint such as platinum, palladium, etc. and the films are stacked one on top of the other with the holes 22, 26, 28 in register and fired. During firing, the ceramic films coalesce into a unitary ceramic structure or monolith. After the firing, the metallized coatings 27 and 30* may be applied in the form of a silver paint. A silver paint coating 33' may also be applied to the bores of the holes 22, 26 and 28 and another silver paint coating 34 may be applied to the peripheral edge of the laminate. The silver paint coatings are cured in an oven. The silver paint coating 33 connects the live electrodes 21 in parallel. The silver paint coating 34 connects the ground electrodes 23 and 24 in parallel.
After firing and applying the silver paint coatings 27, 33 and 34, the multiple capacitor laminate is a compact sealed structure having holes aligned with the pins 6. The multiple capacitor laminate has some filtering effect to reduce radio frequency interference. When so used, the
coating 34 is the ground terminal and the coatings 33 are the live terminals of the filter. To improve the filtering effect, an inductive means such as a lossy ferrite plate is sandwiched between the two multiple capacitor laminates 13, 14 and the assembly is held together by ground terminal 16. The ferrite plate has holes 35 in alignment with the holes in the laminate. The unitary ferrite plate 15- is a convenient construction. It may be replaced by several smaller ferrite plates or by individual ferrite beads telescoped over the pins 6. The active part of the ferrite is the section encircling each pin having an area corresponding to that of a bead.
What is claimed is:
1. A connector, a multiple capacitor filter unit comprising a laminate of a plurality of ceramic dielectric films coalesced into a unitary structure and having a plurality of holes speced from each other and extending through the films of the laminate in the thickness direction, live and ground electrode means on and in capacity relation to each other through films of the laminate, the ground electrode means being margined from the holes and extending to the peripheral edge of the laminate, the live electrode means having a plurality of separate portions electrically insulated from each other respectively extending to the edges of separate holes to provide a plurality of separate capacitors, a conductive coating overlying and encircling the peripheral edge of the laminate and connected to said ground electrode means, conductive coatings overlying the edges of the holes and connected to the respective live electrode means, means of insulating providing sockets on opposite sides of said laminate and aligned with said holes, a pin extending through each hole and through the associated sockets, an electrical connection from each pin to the conductive coating overlying the edges of the hole through which the pin extends, and an electrical connection to the conductive coating overlying and encircling the peripheral edge of the laminate.
2. The connector of claim 1 in which the filter unit comprises two laminates of similar construction, the laminates being spaced from each other with aligned holes, and inductive means in the space between the laminate having holes through which the respective pins extend, said inductive means having separate active portions encircling the respective pins.
3. The connector of claim 2 in which the inductive means comprises ferrite beads telescoped over the pins.
4. The connector of claim 2 in which the sockets and holes provide clearance around the pins so the pins can tfloat to facilitate insertion and removal.
5. The connector of claim 4 in which the electrical connection from one of the pins to its live electrode is a flexible conductive rubber sleeve.
6. A multiple feed through filter comprising a first laminate having a plurality of ceramic dielectric films coalesced into a unitary structure and having a plurality of registering holes extending through the films of the laminate in the thickness direction, and ground and live electrode means on and in capacity relation to each other through films of the laminate, the ground electrode means being margined from the holes and extending to the peripheral edge of the laminate, the live electrode means having a plurality of separate portions electrically insulated from each other respectively extending to the edges of separate holes to provide a plurality of separate capacitors, a conductive coating overlying and encircling the peripheral edge of the laminate and connected to said ground electrode means, conductive coatings overlying the edges of the holes and connected to the respective portions of the live electrode means, a second laminate spaced from the first laminate having a plurality of ceramic films coalesced into a unitary structure, a plurality of holes spaced from each other and extending through the second laminate in the thickness direction, and live and ground electrode means on and in capacity relation to each other through films of the laminate, the ground electrode means of the second laminate being margined from the holes and extending to the peripheral edge of the second laminate, the live electrode means of the second laminate having a plurality of separate portions electrically insulated from each other respectively extending to the edges of separate holes to provide a plurality of separate capacitors, a conductive coating overlying and encircling the peripheral edge of the second laminate and connected to its ground electrode means, conductive coatings overlying the edges of the holes of the second laminate and connected to the respective portions of its live electrode means, the holes of the second laminate registering with the holes in the first laminate, a plurality of conductors each extending through a separate hole in the first laminate and the registering hole in the second laminate and each connected to the conductive coatings on the registering holes through which it extends, inductive means in the space between the laminates having a plurality of active portions each surrounding one of the conductors, and a metal band holding the laminates together and connecting said ground electrode means.
7. The filter of claim 6 in which the inductive means comprises ferrite beads telescoped over the lead wires.
'8. A filter device including an integral capacitive device comprising a unitary ceramic dielectric monolith containing therein is superimposed relationship a first set of parallel capacitor ground electrodes extending in substantially planar form from exterior border to exterior border of the monolith and generally parallel each to others thereof and each such ground electrode having a plurality of areal voids therein, and said monolith and generally parallel each to others thereof and each such ground electrode having a plurality of areal voids therein, and said monolith further containing therein a second set of smaller capacitor elecerodes disposed in parallel relation between electrodes of aid first set but insulated therefrom by respective thin portions of said monolith, and there being between two electrodes of said first set at least two substantially coplanar electrodes of said second set each insulated from the other by said monolith, and a plurality of terminal conductors each extending through aligned ones of the areal voids in said electrodes of the first set and each insulated from the other and from said electrodes of said first set and electrically contacting aligned parallel electrodes of a respective group of electrodes comprised in the said set of smaller electrodes, and means electrically inter-connecting the electrodes of said first set, whereby said monolith contains a plurality of capacitors having a common ground connection and respective other individual terminals, all disposed in a compact spatial arrangement.
9. A filter device according to claim 8, in which guardcircuit conductor means are contained in said monolith disposed in coplanar relationship with respective ones of the electrodes of said second set and encircling and shielding each such electrode from all others thereof and insulated by said monolith from all of said electrodes of said second set of electrodes and from said terminal conductors, said guard-circuit conductor means being electrically connected to the electrodes of said first set.
10. A method of producing a multiple-unit integral capacitive device composed essentially of a monolithic dielectric structure containing a plurality of capacitor units each comprising a plurality of superimposed parallel electrodes of first and second sets thereof, and terminal conductors, said method including the steps of:
forming a plurality of thin rectangular wafer-like sheets of dielectric ceramic greenware;
disposing on one face of each of a first set of said sheets a patterned coat of adherent conductive material extending from border to border thereon but having spaced-apart small areal voids to provide thereon thin capacitor electrodes with spaced areal voids;
disposing on one face of each of a second set of said sheets an array of spaced-apart thin coats of adherent conductive material to provide on each sheet of said second set an array of capacitor electrodes smaller than those on said first set of sheets, and each electrode of said array being areally disposed to register with a respective one of said areal voids when sheets of said first and second sets are superimposed in alternation in a stack;
stacking said first and second sets of sheets in superimposed relationship with coated faces of all of the sheets facing the same direction;
forming holes transversely through the monolithic structure so each hole extends through a middle portion only of each of a respective set of superimposed voids of said first set of sheets;
firing the unitary structure to form a dense rigid monolithic structure; and
applying conductive material over the interior surfaces bounding said holes whereby to electrically interconnect the respective electrodes of said second set of sheets, and separating interconnecting said thin capacitor electrodes.
11. A method as defined in claim 10, including the step of applying a thin conductive stripe between nextadjacent electrodes on the face of each of said second set of ceramic sheets, and electrically connecting the said stripes to the electrodes on said first set of ceramic sheets, whereby to provide a guard means electrostatically isolating next-adjacent ones of the smaller electrodes each from the other.
12. A method as defined in claim 10, including the step of mounting said monolith on a metal bulkhead and electrically connecting said thin capacitor electrodes to said bulkhead.
References Cited UNITED STATES PATENTS 3,160,790 12/1964 Mittler 174-685 3,275,953 9/1966 Coda et a1. 333-79 3,379,943 4/1968 Breedlove 3l726l X 3,426,257 2/1969 Youngquist 3l7-256 HERMAN K. SAALBACH, Primary Examiner T. J. VEZEAV, Assistant Examiner U.S. c1. X.R. 317---256 g