US 3209178 A
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Description (OCR text may contain errors)
D. J. KONEVAL MICRO MODULAR RESONATOR PACKAGE Sept. 28, 1965 She ets-Sheet 1 Filed Nov. 26, 1962 F'IG.6 FIG INVENTOR. DONALD J.'KONEVAL AT TOR NEY I lllll |||l k W E;
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54 i E:] T0 GROUND p '2s,19es D. J. KQNEVAL 3,209,178
MICRO MODULAR RESONATOR PACKAGE Filed NOV. 26, 1962 .2 Sheets-Sheet 2 INVENTOR.
DONALD J. KONEVAL ATTORNEY United States Patent 3,209,178 MICRO MODULAR RESONATOR PACKAGE Donald J. Koneval, Cleveland, ()hio, assignor to Clevite Corporation, a corporation of Ohio Filed Nov. 26, 1962, Ser. No. 239,971 14 Claims. (Cl. 310-91) This invention relates to fabrication of electric circuit components and more particularly to an improved structure and method for packaging micro modular filters.
The invention is particularly applicable to the packaging of miniature piezoelectric resonators, particularly the miniature wafer type utilized in filter circuits. Such miniature resonators may, for example, be of disk-shaped configuration with a diameter less than 0.05 inch and a thickness less than 0.008 inch. It will be apparent that the size of such resonators has necessitated the use of a supporting structure or a package having provision for connection in an electric circuit.
It is often desired to connect a number of miniature resonators in a predetermined circuit arrangement to form a specific type of filter. Five such resonators may be connected, for example, to form a conventional ladder type filter. To achieve optimum circuit miniaturization the resonators utilized in a single band-pass filter, such as the ladder filter, are placed in a single package having internal electrical connections between the various resonators to establish the filter configuration. One package which has been used extensively for a multi-resonator filter comprises a body wafer plate having circular cavities in which resonator disks are placed along with resilient contact disks. The body wafer is enclosed by cover plates which have printed circuit electrode means on the surface thereof for electrical contact with the contact disks. The cover plates are attached by an epoxy adhesive and exert a predetermined pressure on the resonator contact disk to insure electrical contact and to resiliently support the resonator disks.
The above described package is typical of a prior art filter package. Such a package, while serving its intended purpose, has been found to possess certain limitations and disadvantages which affect the accuracy and the manufacturing cost of the filter. Perhaps the most serious disadvantage is the fact that variations in contact pressure causing variations in the resonant frequency of the resonator occur if the dimension of all parts of the package are not maintained to high precision tolerances. For example, in the case of the above described package a vari ation in contact disk dimensions or a variation in cover plate adhesive thickness will affect the contact pressure and result in a frequency or impedance variation. Thus,
extremely high dimensional accuracy must be maintained.
A second disadvantage of the described prior art package is the fact that the circuit of the filter is not complete until the cover plates are attached, prohibiting circuit testing prior to complete assembly of the package. If an electrical defect is then discovered it cannot be remedied without destruction of the package during disassembly. Accordingly, the fabrication cost has been exceedingly high.
It is a principal object of this invention to provide an improved component package possessing ease of assembly and having a low fabrication cost.
Another object of the invention is to provide a package for miniature circuit components which enables the characteristics of the components to be tested prior to complete assembly of the package.
Another object of the invention is to provide an improved micro modular filter package requiring less dimensional accuracy than prior art packages.
In one preferred embodiment of the invention a filter package comprises a wafer supporting plate having a plurality of slots extending between opposite face surfaces of the plate. A resonator disk and resilient contacts are positioned in each of the slots. Electrode means comprising electrically conductive material is fixed by an adhesive to one face surface of the plate and electrically connected to the resilient contacts within the slots to establish the desired filter configuration. Top and bottom covers plates are attached to the face surfaces of the supporting plate. The cover plates do not provide electrodes for the filter circuit nor affect the contact pressure on the resonators, permitting the electrical characteristics of the resonators to be tested and determined prior to complete assembly of the package.
Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, wherein:
FIGURE 1 is a perspective view of an assembled filter package embodying the invention;
FIGURE 2 is an exploded perspective view of the parts of the filter package illustrated in FIGURE 1;
FIGURES 3, 4, 5, 6 and 7 are enlarged details of parts shown in FIGURE 2;
FIGURES 8 and 9 are sections taken along the line 88 of FIGURE 2 illustrating the method of inserting the resonator disks;
FIGURE 10 is a circuit diagram illustrating the equivalent circuit of the filter package disclosed in FIGURES -1 through 9;
FIGURE 11 is a top view of a part shown in FIGURE 2 illustrating the addition of shielding;
FIGURE 12 is an exploded perspective view illustrating a second embodiment of the filter package;
FIGURE 13 is an enlarged detail of a part shown in FIGURE 12;
FIGURE 14 is a fragmentary sectional view taken across slot 84- of FIGURE 12;
FIGURE 15 is an exploded perspective view illustrating still another embodiment of the invention;
FIGURES 16 and 17 are enlarged details of parts shown in FIGURE 15; and
FIGURE 18 illustrates a multiple package filter assembly.
Referring to FIGURE 1 of the drawings, there is shown an assembled micro modular filter package identified generally by the reference numeral 10. For purposes of clarity the assembled package in FIGURE 1 is illustrated approximately ten times its actual size.
The package 10 comprises, as shown more clearly in FIGURE 2, a main supporting plate or wafer 12 having an upper cover plate 14 and a bottom cover plate 16, all of which are formed from suitable electrically non-conductive material. The supporting plate 12 is provided with .a plurality (in this case five) of spaced slots 18, 20, '22, 24 and 26 of rectangular cross-section and extending between the opposite face surfaces of the supporting plate 12 in perpendicular relationship therewith. The slots 18, 20, 22, 24 and 26 may be formed, for example, by ultrasonic machining or other known fabrication techniques applicable to miniature components.
A plurality of resonators (in this case five) 28, 30, 32, 34 and 36 are received by the slots 18, 20, 22, 24 and 26, respectively, and may comprise, for example, ceramic disk-shaped piezoelectric wafers having electrodes on op posite surfaces thereof. As is well known to those skilled in the art such resonators have a resonant frequency dependent on the wafer and electrode dimensions and may be variously polarized to achieve various modes of vibrations, such as, for example, a radial vibrational mode. Since the construction and function of the resonators 28, 30, 32, 34 and 36 form no part of the present invention, further description is deemed unnecessary.
The upper surface of plate 12 is provided with elecslots in supporting plate 12 and have the configurations illustrated in FIGURES 3, 4, 5, 6 and 7, respectively, prior to installation. The foil segments 38, 39, 40, 42 and 44 may be fabricated to the configurations illustrated in FIGURES 3-7 by a photoetching process and then applied by epoxy adhesive or other suitable means to the upper surface of plate 12. Each foil segment is provided with integrally formed contact portions which extend into the associated resonator slot to establish electrical contact according to the electrode pattern.
Referring specifically to the foil segment 38 illustrated in FIGURE 3, this electrode segment is provided with an integral end contact portion 46 which upon positioning of segment 38 on-the surface of plate 12 is bent downwardly along the dashed line into the slot 18 for subsequent contact with one side of disk 28 upon insertion of the same. The other end of segment 38 extends beyond the edge of plate 12 to provide one circuit connector for the filter package.
Foil segment 39, illustrated in FIGURE 4, is similarly provided with an integral contact portion 48 which is bent downwardly along the dashed line for insertion into slot 20 and an extending opposite end defining a second circuit connector for the filter package.
Foil segment 40, as shown in FIGURE 5, is provided with integral contact portions 50 and 52 which are bent along the dashed lines for insertion into slots 22 and 24, respectively, and an integral portion 54 adapted to extend beyond the edge of supporting plate 12, as shown in FIG- URE 2, to provide the third circuit connector for the filter package 10.
Foil segment 42 (FIGURE 6) is similarly provided with integral resonator contact portions 56, 58 and 60 for insertion in the same manner in slots 18, 22 and 26, respectively, and foil segment 44, identical in configuration to segment 42, is likewise provided with contact portions 62, 64 and 66, for insertion into slots 20, 24 and 26, respectively.
When the foil segments 38, 39, 40, 42 and 44 are fixed in position as illustrated in FIGURE 2, two foil contact '9 which is a sectional view similar to FIGURE 8, of slot 24, after installation of resonator 34. As shown in FIG- URE 9, the foil contact portions in each slot assume a slightly curved configuration and exert a slight contact pressure on the resonators to resiliently support the same and insure good electrical contact with the electrodes. It will be apparent that the contact pressure is dependent only on the slot width and dimensions of the foil contact portions.
After installation of the foil segments and resonators in the slots as described above, the circuitry of the filter 'is complete and the frequency response of the filter comprised of resonators 28, 30, 32, 34 and 36 may be checked by means of appropriate electrical test equipment prior to attachment of top and bottom cover plates 14 and 16. This is an important feature since a defective resonator or a resonator subjected to poor contact pressure may be located and readily removed or the condition remedied without damage to the package or electrode means. Inasmuch as the contact pressure on each resonator disk is determined only by the slot width and dimensions of the foil contact portions, subsequent attachment of the cover plates 14 and 16 does not alter the electrical characteristics of the filter. Accordingly, the filter package provides ease of assembly and testing heretofore unachieved.
After the frequency response of the filter section has been tested the cover plates 14 and 16 are attached to the upper and'lowe-r surfaces of supporting plate 12 by a suitable epoxy adhesive to produce the assembled package illustrated in FIGURE 1 with the circuit connectors 38, 39 and 54 extending as illustrated.
In FIGURE 10 there is illustrated the equivalent electrical circuit of the filter package 10. Each of the resonator disks 28, 30, 32, 34 and 36 is shown by its equivalent parallel resonant circuit comprising an inductance (it) having a predetermined series capacitance (b) and a shunting capacitance (c). The circuit connectors 38, 39 and 54 have been diagrammatically illustrated as input, output and ground connectors, to render obvious the circuitry of the foil electrodes shown in FIGURE 2. It will be apparent that the electrode pattern and filter circuit configuration may be varied as desired by variation in the configuration, number and arrangement of the foil electrode elrnents. Thus the specific ladder type filter arrangement of the resonators and electrode segments described is disclosed only for purposes of illustration.
It will also be apparent that the dimensions and size of the parts utilized will vary with the size and number of resonators employed. For purposes of illustration and not of limitation, however, it has been found that the following dimensions are suitable for the parts illustrated in FIGURES l-9 for a five element ladder filter utilizing In the case of several filters assembled from parts of the above listed dimensions for operation at 4.3 megacycles, the individual resonators were found to undergo only an average change in resonant frequency and anti-resonant frequency of 0.06 percent. Accordingly, the error intro- .dued by the assembly of the package was found to be negligible.
In FIGURE 11 there is shown the supporting plate 12 with the addition of shielding to minimize interaction between the series and parallel resonators of the filter circuit disclosed. The shielding means comprises additional foil segments 70 and 72 of triangular configuration and attached to the face surface of plate 12 in the same manner as foil segments 38, 39, 40,42 and 44. The foil segment 72 is provided with a ground connector as shown and foil segment 74 is electrically connected to foil segment 40 or formed integrally therewith as shown when circuit connector 54 is connected to ground. The shielding means comprising segments 70 and 72 is not necessary for satisfactory performance but does produce optimum stop band rejection.
slots 76, 78, 80, 82 and 84 arranged in the configuration shown to receive resonator disks 86, 88, 90, 92 and 94, respectively. The electrode means comprises, in this instance, a printed circuit 96 on the upper face surface of plate 74 and interconnecting the resonator slots to estab lish an electrode pattern for a five element ladder type filter having the equivalent circuit illustrated in FIGURE 10. In this embodiment foil contact segments 98 of the configuration illustrated in FIGURE 13 are utilized to electrically connect the printed circuit means with the resonators as illustrated in FIGURE 14 which is a sectional view of slot 84 with resonator disk 94 inserted. Each foil contact segment 98- is fixed by electrically conductive epoxy adhesive or other suitable means to the printed circuit on the face surface of plate 12 as shown in FIGURE 12 with an end portion bent along the dashed line shown in FIGURE 14 and extending into the asso ciated slot.
At the edges of the supporting plate 12 foil segments 98, 100 and 102 are similarly attached by electrically conductive epoxy adhesive or other suitable means to the printed circuit to provide circuit connectors for the package. As is apparent from the electrode pattern of the printed circuit 96, the filter package illustrated in FIG- URES 12, 13 and 14 also comprises a five element ladder type filter circuit as shown schematically in FIG- URE 10.
In FIGURES 15, 16 and 17 there is illustrated a single resonator package, which utilizes foil electrode segments similar to the embodiment of FIGURES 19. In this embodiment a supporting plate 104 is provided with a single centrally disposed slot 106 which receives a resonator disk 108. The electrode means comprises two foil segments 110 and 112 which are illustrated in detail in FIG- URES 16 and 17, respectively. Foil segment 110 as illustrated in FIGURE 16 comprises an integral circuit connector 114 and a resonator contact portion 116 adapted to be bent along the dashed line for insertion into slot 106 for subsequent electrical contact with one side of resonator disk 108. Segment 112 similarly comprises an integral circuit connector 118 for the package and comprises a contact portion 120 for insertion into slot 106. The foil segments 110 and 112 are attached to the upper surface of supporting plate 104 by an epoxy adhesive or other suitable means with contact portions 114 and 120 positioned in slot 106 to engage opposite sides of disk 108 in the manner described with respect to the individual slots of the embodiment disclosed in FIGURES 1-9.
FIGURE 18 illustrates a multiple package filter formed by stacking a number of filter packages similar to those hereinbefore described to form a more complex filter circuit or to merely provide a common support for a plurality of individual filter packages. From top to bottom there is illustrated three supporting packages 122a, 122b and 1220 adapted to be attached together by adhesive in stacked relationship to form a multiple package assembly. The packages 122a, 12211 and 1220 may comprise any of the embodiments hereinbefore described. For purposes of illustration, however, the multiple package is depicted in FIGURE 18 as comprising three packages of the type disclosed in FIG. 2 and corresponding parts have been given like reference numerals with appropriate suffixes a, b and c.
The individual circuit connectors of packages 122a, 122b and 1220 may be variously interconnected as desired to provide different filter circuit configurations or connected to separate circuits as desired to provide independent commonly supported filter packages.
It will be apparent, in connection with FIGURE 18, that only one cover plate need be provided between adjacent supporting plates. For example, as between packages 122a and 122b, either the bottom cover plate 16a of package 122a or the upper cover plate 14b of package 122!) may be omitted. Similarly, only one plate need be provided between packages 122b and 1220.
The disclosed embodiments and illustrated applications of the invention are exemplary of a few of the many modifications which are possible. It will be apparent that the invention provides a filter package possessing ease of assembly and which permits appropriate circuit testing of the filter prior to scaling or complete assembly of the package and therefore accomplishes the objects of the invention.
While there have been described what at present are believed to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is aimed, therefore, to cover in the appended claims all such changes and modifications as fall within the true spirit and scope of the invention.
What is claimed and desired to be secured by United States Letters Patent is:
1. A package for a circuit component comprising: a supporting member of insulating material having at least one slot extending from a face surface of said member in substantially perpendicular relationship to said face surface for receiving the circuit component; electrode means for the circuit component on said face surface including contact means within said slot adapted to be engaged by the component; and a cover member of insulating material attached to said face surface to enclose said electrode means and said slot.
2. A resonator package comprising: a supporting plate of insulating material having a slot extending substantially perpendicular from one face surface thereof; a piezoelectric resonator disk positioned in said slot in substantially perpendicular relationship with said face surface; electrode means on said face surface and including contact means extending into said slot for electrical contact with said resonator disk; and a cover plate of insulating material attached to said face surface.
3. A resonator package as claimed in claim 2 wherein said electrode means comprises segments of electrically conductive foil material adhered to said face surface and said contact means comprises integral contact portions extending from said foil segments into said slot; said foil segments additionally having integral circuit connector portions extending beyond the edge of said supporting plate.
4. A resonator package as claimed in claim 2 wherein said electrode means comprises a printed circuit on said face surface and said contact means comprises segments of electrically conductive foil material adhered to said printed circuit at the edges of said slot and extending into said slot for electrical contact with said resonator disk.
5. A resonator support package comprising: a supporting plate of insulating material having at least one slot extending perpendicularly between oppositely disposed face surfaces of said plate; a piezoelectric resonator disk positioned in said slot and having electrodes on opposite sides thereof; a pair of resilient electrically conductive foil contact segments extending into said slot on opposite sides of said resonator disks to engage said electrodes respectively and to resiliently support said disk within said slot; electrode means on one face surface of said supporting plate electrically connected to said foil segments; and cover plates of insulating material fixed to said opposite face surfaces respectively of said supporting plate.
6. A resonator support package as claimed in claim 5 wherein said electrode means comprises a printed circuit.
7. A resonator support package as claimed in claim 5 wherein said electrode means comprises electrically conductive foil material formed integrally with said contact segments.
8. A filter package comprising: a supporting plate of insulating material having a plurality of spaced slots extending between the oppositely disposed face surfaces of said plate; a plurality of resonator disks positioned in said slots respectively and each defining a plane perpendicular to the face surfaces of said supporting plate; electrode means on one face surface of said plate electrically connecting said resonator disks in a predeterminedv filter configuration; external circuit connecting means for said electrode means at the extremity ofsaid supporting plate; and cover plates of insulating material fixed by adhesive to the opposite face surfaces of said sup: porting plate to seal the same.
9. A filter package as claimed in claim 8 further including shielding means adhered to the face surface of said supporting plate for shielding the series and shunt resonator disks in said filter circuit configuration to prevent interaction between the same.
10. A filter package comprising: a rectangular supporting plate of insulating material having a plurality of spaced slots extending between oppositely disposed face surfaces of said plate; a plurality of resonator disks positioned in said slots respectively and each defining a plane perpendicular to the face surfaces of said supporting plate; a pair of resilient electrically conductive foil segments extending into each of said slots on pposite sides of the resonator disk therein to electrically contact the disk and to resiliently support the same within the slot; a printed circuit on one face surface of said plate electrically connected to said contact segments and operative to connect .said resonator disk in a predetermined circuit filter configuration; circuit connecting foil segments adhered to said printed circuit at the extremity of said supporting plate; and cover plates of insulating material fixed by adhesive to the opposite face surfaces of said supporting plate to seal the same.
11. A filter package comprising: a supporting plate of insulating material having a plurality of spaced slots extending between oppositely disposed face surfaces of said plate; a plurality of resonator disks positioned in said slots respectively; a plurality of foil segments fixed by adhesive to the face surface of said plate and having integral portions extending into said slots to resiliently contact opposite sides of said disks to connect said disks in a predetermined filter configuration; said foil segments having integral portions extending beyond the extremity of said plate to define external circuit connectors; and cover plates of insulating material fixed by adhesive to the oppositely disposed face surfaces of said supporting plate to seal the same.
12. A filter package comprising: a resonator supporting plate of insulating material having a plurality of spaced slots extending between the oppositely disposed face surfaces of said plate; a plurality of resonator disks positioned in said slots respectively; means forming an electrode pattern on one of said face surfaces electrically connecting said disks in a predetermined filter configuration; and cover plates of insulating material attached to said face surfaces respectively to enclose said supporting plate and disks.
13. A filter package comprising: an assembly comprising a plurality of stacked supporting plates each having at least one slot extending substantially perpendicular from one face surface thereof; resonator disks positioned in said slots; electrode means for each resonator disk on said one face surface of each of said supporting plates; and top and bottom cover plates fixed to said assembly to enclose the same.
14. A filter package comprising: an assembly comprising a plurality of stacked supporting plates each having at least one slot extending substantially perpendicular from one face surface thereof; resonator disks positioned in said slots; electrode means for each resonator disk on said one face surface of each of said supporting plates; insulating plates between adjacent supporting plates; said insulating plates and supporting plates being fixed together by adhesive to provide a sealed package.
References Cited by the Examiner UNITED STATES PATENTS 2,177,629 10/39 Foster 3 l09.1 2,327,487 8/43 Bach 3109.7 2,434,266 1/48 Fruth et a1 310-97 2,771,663 11/56 Henry 3109.1
MILTON o. HIRSHFIELD, Primary Examiner.