Continuous interconnection between dissimilar materials

Abstract

To provide structures having one or more media extending between two heterogeneous materials to form a continuous interconnect between the materials, and / or formation of such structures.SOLUTION: A deformable electronic device comprises: a substrate 32, 34; an encapsulant 38; a trace 36 formed from a deformable conductor disposed between the substrate and the encapsulant; a pattern of conductive material 30; and an interconnect 40 electrically coupling the trace and the pattern of conductive material. The interconnect comprises the deformable conductor. Preferably, the deformable conductor is a conductive gel. Preferably, the deformable electronic device further comprises a stencil layer positioned between the encapsulant layer and the substrate. Preferably, the stencil layer contains, at least in part, the deformable conductor. Preferably, the pattern of conductive material is positioned on the substrate.SELECTED DRAWING: Figure 10

Description

Background Art

[0001] (Cross - reference to Related Applications) This application claims priority to U.S. Provisional Patent Application No. 62 / 853,481, filed May 28, 2019, which is incorporated by reference.

[0002] (Technical Field) The inventive principles of this patent disclosure generally relate to the interface between two dissimilar materials, and more specifically to a structure having one or more media that extend between two dissimilar materials and form a continuous interface between the materials, and / or a method of forming such a structure.

Summary of the Invention

[0003] The structure includes a first material, a second material joined to the first material at a joint between the first material and the second material, and one or more media that extend across the joint and form a continuous interface between the first material and the second material, where the first material and the second material are dissimilar materials. The structure further includes a transition portion at the joint between the first material and the second material. The transition portion includes an overlapping connection portion. The one or more media include a functional material. The functional material is conductive. The functional material includes a conductive gel. The first material is substantially more rigid than the second material. The first material is substantially more elastic than the second material. The structure further includes a first sealant disposed on the first material so as to substantially enclose a portion of the media. The structure further includes a second sealant disposed on the second material so as to substantially enclose a portion of the media. The first material includes a via through which at least a portion of the media passes. The structure includes an overlapping connection portion at the joint between the first material and the second material, and the via passes through the overlapping connection portion. The structure further includes an electrical component attached to the first material and electrically coupled to the media.

[0004] The joint between the first material and the second material includes the first joint, and the structure further includes the third material joined to the second material at the second joint between the second material and the third material, the medium extending beyond the second joint and forming a continuous interconnection between the first material, the second material and the third material, the second material and the third material being heterogeneous. The medium is conductive, and the structure further includes a first electrical component attached to the first material and electrically connected to the medium, and a second electrical component attached to the third material and electrically connected to the medium.

[0005] The sensor structure includes a first substrate containing a first material, a conductive contact layer containing a second material provided on the first substrate, a second substrate containing a third material provided on the first substrate, and a conductive gel arranged in a pattern on the second substrate to form a continuous electrical interconnection with the conductive contact layer, wherein at least two of the first, second, and third materials are heterogeneous. The sensor structure further includes electrical components provided on the second substrate and electrically connected to the continuous electrical interconnection. The first substrate includes vias to which the continuous electrical interconnection connects to the conductive contact layer.

[0006] The method includes the steps of joining a first material to a second material at a joint, and forming a continuous interconnection between the first material and the second material beyond the joint, wherein the first material and the second material are of different types. The method further includes the step of sealing the continuous interconnection. [Brief explanation of the drawing]

[0007] The figures are not necessarily drawn to scale, and elements having similar structure or function are generally represented by the same reference number for the purpose of illustrating the entire figure. The figures are intended solely to facilitate the description of the various embodiments described herein. The figures do not illustrate all aspects of the teachings disclosed herein, nor do they limit the claims. Not all parts, connections, etc., may be shown, and not all parts may be numbered, in order to prevent the figures from becoming obscured. However, patterns of component configuration are readily apparent from the figures.

[0008] [Figure 1] Figure 1 shows one embodiment of a structure relating to several inventive principles of this patent disclosure.

[0009] [Figure 2] Figure 2 shows another embodiment of a structure relating to some of the inventive principles of this patent disclosure.

[0010] [Figure 3] Figure 3 is an exploded perspective view illustrating an exemplary embodiment of the design of an interconnection part relating to some of the inventive principles of this disclosure.

[0011] [Figure 4] Figure 4 is a cross-sectional view of another exemplary embodiment of a heterogeneous structure relating to some of the inventive principles of this disclosure.

[0012] [Figure 5] Figure 5 shows another exemplary embodiment of a heterogeneous structure using conductive gel as wiring according to some of the inventive principles of this disclosure.

[0013] [Figure 6] Figure 6 shows another embodiment of a structure having continuous interconnections relating to some of the inventive principles of this disclosure.

[0014] [Figure 7]Figure 7 is a side view showing one embodiment of a structure having a continuous interconnection between dissimilar materials relating to some of the inventive principles of this disclosure. [Figure 8] Figure 8 is a top view showing one embodiment of a structure having a continuous interconnection between dissimilar materials relating to some of the inventive principles of this disclosure.

[0015] [Figure 9] These are other side views of the structures shown in Figures 7 and 8.

[0016] [Figure 10] Figure 10 is a cross-sectional view showing another embodiment of a structure having a continuous interconnection between dissimilar materials relating to some of the inventive principles of this disclosure.

[0017] [Figure 11] Figure 11 is a cross-sectional view of another exemplary embodiment of a heterogeneous structure relating to some of the inventive principles of this disclosure. [Modes for carrying out the invention]

[0018] Figure 1 shows one embodiment of a structure relating to some of the inventive principles of this patent disclosure. The system in Figure 1 includes at least two dissimilar materials, material A (10) and material B (12). Material A and material B are dissimilar in that they have at least one of different mechanical properties, constraints, processing parameters, etc. One or more media 14 extend between material A and material B, forming a continuous interconnection between the materials. Figure 2 shows another embodiment similar to Figure 1, but the embodiment in Figure 2 includes a transition A / B (16) between material A and material B.

[0019] Suitable media 14 include, for example, viscous, elastic, viscoelastic, and / or other materials that deform in response to one or more deformations of material A and material B and then return to their original form when one or more of material A and material B return to their original form. The medium (medium or media) 14 returns to its original form by its own action (e.g., when the medium is an elastic material) or by the action of one or more of material A and material B returning to their original form (e.g., when the medium is a fluid).

[0020] In some embodiments, the medium 14 includes one or more functional materials having at least one function that is not primarily structural, such as conduction of electricity, light, sound, etc., sensing of one or more stimuli such as stress, strain, pressure, temperature, elongation, mass transport (of the material itself), heat transport, transmission of force, mechanical coupling such as motion, pressure, vibration, and / or other types of functions. In some embodiments, the functional material has at least one fluid property or fluid component, such as, for example, as a fluid component of a fluid phase material or a gel material.

[0021] In some embodiments, the functional material is implemented as a viscoelastic material having both a fluid component and a solid component. Such materials exhibit, for example, an electrical response function such as electrical conductivity or serve as mechanical interconnects, operative interconnects, fuel lines or fluid reservoirs, or other functions. The material of the viscoelastic interconnects is arranged in any suitable shape to correspond to the intended function.

[0022] In hydrodynamics, G *G'' represents a composite shear modulus that includes two components G' and G'', referred to as the storage modulus and loss modulus, respectively. The storage modulus essentially represents the elastic component of the material, while the loss modulus represents the viscous or liquid component of the material. In some embodiments, by selecting a functional material to have a G' higher than one or both of material A or material B, the functional material can withstand a certain degree of compression during the molding and / or use of the structure. In some embodiments, depending on the implementation, the storage modulus of the functional material is considered "higher" than one or both of material A or material B if it is high enough that the functional material can withstand compression or other strain stimuli during molding and / or use while maintaining its function after the molding and / or use of the structure.

[0023] Differences in the mechanical properties of material A and material B include elastic modulus (e.g., Young's modulus, shear modulus, bulk modulus, etc.), hardness (Shore hardness, Mohs hardness, Brinell hardness, Rockwell hardness, etc.), strength (tensile strength, compressive strength, etc.), and density.

[0024] Different processing parameters for material A and material B include temperature, pressure, time, reagents (e.g., reactants, solvents, catalysts, activators, etc.), and exposure to UV, IR, RF, and sonication.

[0025] Different constraints on material A and material B include deformation limits (e.g., due to the presence of mounted rigid components, placement on objects such as the human body or highly sensitive machinery) and exposure limits (e.g., to temperature, radiation, UV, IR, RF, ultrasound, chemicals, etc.).

[0026] The medium 14 forming the interconnect is formed on one or more surfaces of material A and / or material B, or transition A / B, within a passage penetrating material A and / or material B, or transition A / B, or in any other arrangement that forms an operable interconnect between material A and material B.

[0027] The transition section A / B may, as necessary, include overlapping, alternating arrangement, material gradients, etc., between material A and material B, and / or one or more intermediate materials, transition materials, interference materials, etc., between material A and material B.

[0028] One or more deformations of material A and material B, and the corresponding deformations of the interconnection part 14 may correspond to one or all of the following forces in one or more of material A and material B: tensile force, compressive force, stretching force, bending force, torsional force, bulk force, etc.

[0029] Examples of interconnections formed by the medium 14 include mechanical interconnections, electrical interconnections, electronic interconnections, electromechanical interconnections, electromagnetic interconnections and / or other electroactive interconnections, optical transporters, photon transporters, acoustic transporters, mass transporters, and the like.

[0030] Suitable materials for use as material A and material B include, in any combination, silicone-based materials containing polydimethylsiloxane (PDMS), urethanes containing thermoplastic polyurethane (TPU), ethylene propylene diene monomer (EPDM), neoprene, as well as all kinds of natural and / or synthetic polymers including rubber and plastic materials such as epoxy, pure metals and alloys, woven or nonwoven fabrics, wood, leather, paper, fiberglass, carbon and other composite materials, or combinations thereof.

[0031] Suitable materials for use as the medium 14 forming the interconnection include, but are not limited to, deformable conductors containing conductive gels such as gallium-indium alloys, some examples of which are disclosed in U.S. Patent Application Publication 2018 / 0247727, published on August 30, 2018, which is incorporated by reference. Other suitable electroactive materials include any conductive metal, including gold, nickel, silver, platinum, copper, etc.; semiconductors mainly composed of silicon, gallium, germanium, antimony, arsenic, boron, carbon, selenium, sulfur, tellurium, etc.; semiconductor compounds including gallium-arsenide, indium antimony, and oxides of various metals; organic semiconductors; and conductive nonmetallic substances such as graphite. Other conductive gels include gels mainly composed of graphite or other forms of carbon, and ionic gels. Suitable non-electrical compositions include, for example, various other gels such as silica gel, and chafing fuels such as Sterno. Other examples include liquids such as water, oil, ink, and alcohol, which may or may not be electroactive, as well as elastic materials, which may or may not be electroactive.

[0032] Some additional inventive principles of this patent disclosure relate to the use of structures such as those shown in Figures 1 and 2. These function as interconnects between dissimilar materials that mount various special components in deformable electronic assemblies, such as flexible hybrid electronics (FHE) assemblies. In some non-limiting embodiments, the interconnects may span dissimilar joints between deformable circuit boards, such as flexible printed circuit boards (FlexPCBs) and / or stretchable PCBs (StretchPCBs), and other deformable structures, such as TPU structures or silicone structures. Techniques used to form such structures include molding, adhesive bonding, thermoforming, tape bonding, ultrasonic bonding, and the like. In some embodiments, such techniques can be combined with FHE techniques and one or more interconnects of this patent disclosure to produce one or more integrated fabric / electronic assemblies for various applications, for example, in industrial electronics, consumer electronics and / or portable electronics.

[0033] In deformable electronic devices such as FHEs, interconnections in mixed modes, particularly between rigid and flexible materials, or between rigid components and materials conforming to non-linear shapes, can present challenges. FHEs and other deformable electronic devices are applied to IoT (Internet of Things) and portable applications. In such applications, electronic devices have closely related mechanical components that were previously considered distinct from the mechanisms of conventional electronic assemblies. Materials such as fabrics, rubber membranes, and thermoformable plastics directly incorporate electronic elements to support smart or actively controlled functions.

[0034] Special solders, conductive adhesives, or mechanical connectors are used for interconnections between dissimilar materials. However, some of these require compatibility between individual wirings built on two dissimilar substrates, each with its own unique mechanical constraints. This necessitates expertise in both dissimilar material interconnection and mechanical design, creating significant constraints and costs in the design of FHEs or other deformable electronic devices.

[0035] The inventive principle of this patent disclosure can avoid potential interconnection problems such as multimodal metallization by employing continuous interconnects. These continuous interconnects are fabricated by fabricating conductive gels and / or other conductive functional materials through vias or other passages cut or formed in a mixed-material substrate, printing them directly onto the substrate, or otherwise appropriately distributing them onto the substrate. In some embodiments, continuous circuits including vias and other structures having single and / or mixed-material multilayer circuit configurations are fabricated by interconnects formed from conductive gels and / or other conductive functional materials. In some embodiments, components may be directly coupled to conventional electronic elements, including surface mount components, flex circuits, and conductive fabrics, via vias in an adhesive substrate filled with conductive gels and / or other conductive functional materials. All of these configurations can create ohmic and low-impedance contacts. These contacts have the potential to withstand dynamic loads on the structure, both during final assembly where dynamic movement is expected, and during use in applications such as mounted electronics and strain monitoring electronics, for example, resistance to strain cycles and / or bending tests.

[0036] In some embodiments, the inventive principles of this patent disclosure apply to a wide range of substrate materials and manufacturing methods. These enable both the mounting of rigid surface-mount components onto FlexPCB or StretchPCB substrates and the creation of mechanically robust interconnects attached to PCB components, which are connected by continuous wires made of conductive gel and capable of withstanding substantially large strains.

[0037] In some exemplary embodiments, an FHE or other deformable electronic device includes both a first substrate portion for mounting surface mount components and a second substrate portion, for example, made of a conductive gel, which functions as a relatively high-stretch fabric-integrated conductor and / or strain gauge. The high-stretch portion of the circuit provides a variable resistor and / or conductive path to the low-stretch flex circuit. The low-stretch circuit may mount, for example, one or more passive and / or active surface mount technology (SMT) components that can produce a visual output of the stretching and contracting experienced by the high-stretch portion.

[0038] Materials used in FHE devices or other deformable devices relating to some of the inventive principles of this patent disclosure include, but are not limited to, any TPUs, including, for example, low Shore A TPUs and / or other high Shore A TPUs; thermosetting and / or epoxy films; silicones, for example, any type of curable silicone applied to highly stretchable knitted fabrics; copper-clad polyamides, metal-clad polyamides, or other substrates used in FlexPCBs, Stretch PCBs, etc.; and any active and / or passive through-hole and / or surface mount components. In some exemplary embodiments, copper-clad polyamides and SMC components are used to form stable electrical connections in vias filled with conductive gel, for example, as components of hybrid assemblies.

[0039] Figure 3 is an exploded perspective view showing an exemplary embodiment of an interconnect design suitable for use in FHE devices or other devices relating to some of the inventive principles of this patent disclosure. Two pads 101 and 102, having diameters D1 and D2 respectively, are printed on separate layers of dissimilar substrates A (103) and B (104) using holes that penetrate the pads, for example, so that electrical conductivity is achieved. Pad 101 connects to wiring 107 on substrate A, and pad 102 connects to wiring 108 on substrate B.

[0040] Pad size and via hole size are selected to facilitate the design of the circuit board with manufacturability in mind. In some exemplary embodiments of dissimilar interconnections on flexible and / or stretchable substrates, the sizes of these features are selected in accordance with the expected deformation of the substrate and / or to facilitate the assembly and inspection of the dissimilar interconnections. In some embodiments, these via pads are directly connected to the surface of the circuit (e.g., a polyamide circuit) or to surface mount components bonded to the pads.

[0041] In the example shown in Figure 3, a transition substrate A / B(105) with vias 106 having a diameter D3 is shown between the overlapping portions of substrates A and B, although in some embodiments the transition substrate may be omitted. The materials used for substrates A, B and transition substrate A / B (if used) are selected from any of the materials specified above or other suitable materials. Fillers for pads, wiring and vias are carried out with conductive gel or any other suitable conductive material. Figure 4 is a cross-sectional view of another exemplary embodiment of a heterogeneous structure (implemented as a layup in some embodiments) using a conductive gel and / or other interconnecting medium 114 as wiring according to the present disclosure. Substrate A (110) overlaps and is directly bonded to substrate B (112). In other embodiments, a transition substrate is used. In this embodiment, vias 116 are formed through substrate A so that, for example, wiring 122 and / or pads 124 on substrate A are aligned on the upper surface of wiring 118 and / or pads 120 on substrate B, thereby causing the conductive gel in the vias 116 of substrate A to directly contact the pads 120 on the upper surface of substrate B.

[0042] The structure shown in Figure 4 includes one or more encapsulants to regulate and / or protect the wiring, pads and / or vias of the conductive gel and / or other interconnecting medium 114. For example, at least a portion of substrate A is covered with encapsulant A(126), and at least a portion of substrate B is covered with encapsulant B(128). Any suitable material can be used for the encapsulant, e.g., silicone-based materials such as PDMS, TPU, urethane, epoxy, polyester, polyamide, varnish and protective coatings, and / or any other material that helps to hold the assembly together. Substrates 110 and 112 are joined using any suitable technique, including adhesive bonding, thermoforming, tape bonding, ultrasonic bonding, etc.

[0043] A useful application for the structure shown in Figure 4 is one in which substrate A is made of a material for mounting one or more electronic components, while substrate B is made of a material for providing connections to remote sensors, displays, electronic modules, etc. For example, substrate A is made of a relatively rigid material, while substrate B is made of a relatively flexible and / or stretchable material.

[0044] In some embodiments, vias 116 can be omitted by forming wiring 122 on the underside of substrate A(110). In such embodiments, sealant A(126) is applied to the underside of substrate A(110). In some embodiments, sealant A(126) and sealant B(128) are combined as a single component.

[0045] In some embodiments, any of the structures described herein, in addition to some or all of the structures shown in Figure 4, may be manufactured using at least partially any of the materials and / or manufacturing techniques described herein, which are incorporated by reference in U.S. Patent Application Publication No. 2020 / 0066628, published on February 27, 2020, and may be used in combination with any of the methods and / or products described herein.

[0046] Figure 5 shows another exemplary embodiment of a heterogeneous structure using a conductive gel as wiring according to some of the inventive principles of this patent disclosure. In the embodiment shown in Figure 5, a ribbon of thermosetting plastic laminate 130 (material A) overlaps with a ribbon of TPU 132 (material B) in an overlapping region 134 (A / B). For example, a heterogeneous interconnecting medium made from a eutectic gallium alloy has a first portion 136 on material A, a second portion 138 on material B, and a transition portion 140 in the overlapping region 134. All three portions of the wiring are sealed with one or more encapsulants, such as silicone, TPU, urethane, epoxy, etc.

[0047] The thermosetting plastic (material A) and TPU (material B) have substantially different mechanical properties, connected by continuous conductive wiring, thus forming heterogeneous interconnections that transition between the two dissimilar materials. For example, in some embodiments, the thermosetting plastic laminate (material A) is substantially more rigid than the TPU (material B).

[0048] An electromechanical connector, such as the solderable connector 142, overlaps with a second portion 138 of the wiring in an overlapping region 144, forming another dissimilar electrical connection between the continuous wiring and any other electrical equipment. Alternatively, in some embodiments, a polyamide layer is bonded to the conductive fabric as a terminal layer to provide an interconnection between a conductive gel sealed with TPU or silicone and a solderable connector mechanically connected to the conductive fabric.

[0049] Figure 6 shows another embodiment of a structure having a continuous interconnection according to the present disclosure. In the embodiment shown in Figure 6, an outer ring 150 and an inner ring 152 of conductive gel are patterned on a first substrate 154 (material A) formed from a relatively rigid material such as thermosetting plastic. The first substrate 154 transitions to a second substrate 156 (material B) formed from a relatively flexible and / or stretchable material such as silicone. The first substrate 154 and the second substrate 156 transition by overlapping, butt-jointing, or other means. A first linear wiring 158 electrically connected to the outer ring 150 is patterned on the first substrate 154 and the second substrate 156 so as to span the transition between material A and material B. A second linear wiring 160 electrically connected to the inner ring 152 is patterned on the first substrate 154 and the second substrate 156 so as to span the transition between material A and material B.

[0050] One or more two-terminal electronic components, such as light-emitting diodes (LEDs) 162, are mounted on the first substrate 154 such that one terminal is in direct contact with each of the inner and outer rings. The first substrate 154 is sealed with a transparent encapsulant, such as silicone, so that the LEDs are visible through the encapsulant. The second substrate is sealed with another layer, such as silicone, with linear traces 158 and 160 bonded between them. The dashed lines on the linear traces 158 and 160 are covered by the encapsulant on the second substrate 154, which is not transparent in some embodiments.

[0051] In some embodiments, a fabric mesh may be applied to the first substrate 154, for example, by embedding it inside a encapsulant or by bonding it with another encapsulant, in order to provide a pattern of conductive gel formed thereon and selective strain limiting of the LED.

[0052] Therefore, the embodiments shown in Figure 6 provide, in some embodiments, an electronic assembly in which a relatively rigid but flexible and / or stretchable substrate 154 (material A) provides a base for electronic components, while a relatively more flexible and / or stretchable substrate 156 (material B) provides electrical connections to the base, without using any solid wires.

[0053] Conductive gels made from gallium alloys, such as those described in U.S. Patent Application Publication No. 2018 / 0247727, are particularly useful for use in dissimilar material interconnections because they can be patterned on a wide variety of substrates, including TPU, silicone, epoxy, EPDM, and various thermosetting elastomers. In some embodiments, the patterning method is essentially graphic, forming a mechanical bond between the substrate and the conductive gel. In some embodiments, functional patterns can be wetted on many substrates because there is no curing step or chemical reaction. For example, in gallium-indium-tin eutectic alloy compositions, the nanostructure of crosslinked gallium oxide is induced, allowing the material to be patterned on various substrates in a controllable manner by changing viscosity and wetting parameters. Furthermore, because eutectic gallium alloy gels conduct in an amorphous fluid state, they do not have structures that break under strain cycles and can be resistant to strain cycles up to the substrate's limits. Thus, they provide an effective solution for dissimilar material interconnections in FHE and many other applications, particularly in critical hard-to-soft transition areas. Furthermore, eutectic gallium alloy gels possess excellent electrical properties that provide low-resistance DC connections and transmission line parameters (primarily S11) above 5 GHz.

[0054] Figures 7 and 8 are a side view and a top view, respectively, of an embodiment of a structure having a continuous interconnection between dissimilar materials relating to some of the inventive principles of this patent disclosure.

[0055] Embodiments in Figures 7 and 8 include a first heterogeneous substrate 18, a second heterogeneous substrate 20, and a third heterogeneous substrate 22. In this example, the first substrate 18 is rigid TPU, the second substrate 20 is more flexible but still rigid TPU, and the third substrate 22 is flexible TPU; however, the principles of the present invention are not limited to these details, and any combination of materials having various properties can be used. The first and second substrates are joined to each other at a joint 19 using any suitable bonding technique, and the second and third substrates are joined to each other at a joint 21 using any suitable bonding technique. The parts in Figures 7 and 8 are not necessarily to scale. For example, the substrates are made from very thin sheet-like material, in which case the vertical scale in Figures 7 and 8 is exaggerated.

[0056] Wiring of a conductive medium, such as a conductive gel, is formed on the upper surface of the substrate as a U-shaped pattern 28, extending beyond the joint between the substrates. The ends of the U-shaped pattern 28 are terminated with conventional electrical contact pads, contact pads 24 and 26, due to the rigidity characteristics of the first substrate 18. Although not shown in Figures 7 and 8, a sealing material is formed to cover the U-shaped pattern 28 and the upper surfaces of substrates 18, 20, and 22.

[0057] Figure 9 is another side view showing the deformation of the structures in Figures 7 and 8, where, as indicated by R1 and R2, different substrates provide different radii of curvature, resulting in structures that can bend in response to various forces. In some embodiments, such structures function as strain reducers.

[0058] Furthermore, the structures in Figures 7 and 8 may include transition zones between TPU and epoxy, silicone and epoxy, and silicone and other materials such as fabric or TPU. In some embodiments, depending on the details of the implementation, it is particularly beneficial to have a continuous interconnection zone between TPU and silicone, as fabricating electrical connections to silicone tends to be difficult, while fabricating electrical connections to TPU tends to be relatively easy. Therefore, by arranging the electrical connections on a TPU substrate and then migrating them to silicone, a more sensitive substrate for sensors made from a deformable conductor such as a conductive gel can be provided.

[0059] In some embodiments, after printing the circuit using a stencil, flexograph, or other deposition process, a sealing layer with deformable conductive vias may be added, or the exposed circuit may simply be left as is. An integrated circuit (IC) or other electronic device is then placed on the circuit. A metal layer on the IC forms low-impedance ohmic contact with the conductive gel. In some embodiments, the IC (or packaged surface mount component (SMC)) may be held in place by the substrate itself being adhesive. Alternatively, an adhesive may be placed on the land area or on the IC (or SMC). Finally, the sealing layer may be placed to cover the assembly in order to hold the conductive gel and the IC in place.

[0060] In some embodiments relating to the inventive principles of this patent disclosure, having a highly flexible / conformable conductor is beneficial for any of the flexible interconnect mounting processes, direct die mounting processes, direct IC mounting processes, and / or flexible interconnect COB (chip-on-board) processes. In some embodiments, this is achieved by using a conductive gel, for example, a gallium-indium-tin alloy mixed with oxides and micron-scale particles to control viscosity. In some embodiments, such techniques can be utilized with a metal layer and other conformal conductors that are in low-impedance contact.

[0061] In other embodiments relating to some of the inventive principles of this patent disclosure, a gasket made of a material such as EPDM (ethylene propylene diene monomer) has a pattern of deformable conductors arranged to sense the performance of the gasket. Since it is relatively difficult to attach electrical contacts to EPDM, the deformable conductors are coupled via a continuous interconnection between the EPDM gasket and another material such as TPU, which is a good substrate for the electrical contacts. Thus, the sensing circuit is connected to the contacts on the TPU substrate while providing good electrical connections to the deformable conductor pattern in or on the EPDM gasket.

[0062] Figure 10 is a cross-sectional view of another embodiment of a structure having a continuous interconnection between dissimilar materials relating to some of the inventive principles of this patent disclosure. The embodiment of Figure 10 includes a pattern of conductive material 30 formed on a first substrate 32. The first substrate 32 is mounted on a second substrate 34 having wiring 36 of a deformable conductor, such as a conductive gel. A sealant 38 covers the second substrate 34 and the wiring 36. Vias 41 and 43, which penetrate the first substrate 32 and the second substrate 34, respectively, allow the deformable conductor to form a continuous interconnection 40 between the pattern of conductive material 30 and the wiring 36 on the second substrate 34. By having any or all of the layers shown in Figure 10 have one or more dissimilar properties, and by using a functional material such as a conductive gel for the continuous interconnection 40 and / or wiring 36, the assembly shown in Figure 10 can be manufactured and / or operated while eliminating or reducing problems related to material fatigue, material creep, galvanic action between multiple conductors, etc.

[0063] The embodiment shown in Figure 10 is used, for example, in bioelectric sensors such as electrocardiograms (ECG or EKG) and electromyograms (EMG). In such embodiments, the conductive material 30 is made from conductive silicone, copper cladding, or other materials suitable for implementing electrodes that are in contact with the patient's body. The substrates 32 and 34 are made from materials that are, for example, rigid enough to mount one or more electronic components, but flexible enough to be in comfortable contact with the patient's body. Examples of such materials include TPU, polyamide, thermosetting epoxy, and thermosetting plastics.

[0064] In some exemplary embodiments, the conductive material 30 is implemented as a conductive silicone that can withstand contact with the skin, while the second substrate 34 is implemented in epoxy to form the base for electronic components and / or other layers of edge wires for circuit boards. The first layer 32 is implemented in TPU to protect the patient from contact with the epoxy substrate 34, which may be irritating to some patients.

[0065] The conductive wiring 36 is shown on the underside of the second substrate 34, but in some embodiments, the conductive wiring 36 may penetrate the second substrate 34, which acts as an in-place stencil for forming the wiring 36 that is wrapped between the first substrate 32 and the encapsulant 38.

[0066] In some embodiments, additional layers of the substrate may be included, which have additional vias, wiring, etc., to form a functional circuit comprising one or more electrical and / or electronic components.

[0067] In some embodiments, the structure shown in Figure 10 includes an interface 44 for connecting the assembly to one or more other devices. For example, in some embodiments, the conductive wiring 36 transitions to one or more terminals for coupling the assembly to a cable or other conductive device, for example, to read data from an integrated sensor. In other embodiments, the interface 44 may transition to other dissimilar joints, such as shown in Figure 4, which transition to a relatively highly extensible conductive assembly for connecting the assembly to other devices.

[0068] In some embodiments, one or more substrates shown in Figure 10 are implemented as fabric layers, or fabric layers are added as additional layers. Such fabric layers are included, for example, in the case of bioelectric sensors, to provide comfort to the patient. Furthermore, additionally or alternatively, such fabric layers are used to integrate the assembly into clothing or decoration, or other wearable devices such as fasteners. Moreover, multiple assemblies as shown in Figure 10 may be integrated into a single garment or decoration or other wearable device using one or more flexible and / or stretchable substrates that form electrical and / or electronic interconnections between the assemblies.

[0069] Figure 11 is a cross-sectional view of another exemplary embodiment of a heterogeneous structure according to the present disclosure. The embodiment shown in Figure 11 includes components similar to those shown in the embodiment of Figure 4, but the embodiment of Figure 11 further includes a third substrate C(166) that forms a second junction with substrate B(112). Wires 168, wires and / or pads 170, vias 172 and / or vias 174 extend through wires 122 and / or pads 124, vias 116, and wires 118 and / or pads 120 to form a continuous interconnection formed by the interconnection medium 114. The other encapsulant C(176) encapsulates a portion of the interconnection within or on substrate C. In some embodiments, any of encapsulant A, encapsulant B, and / or encapsulant C is formed as a single layer.

[0070] In some embodiments, the structure shown in Figure 11 is used, for example, to provide a continuous functional interconnect between component A and component B. For example, component X is implemented as a sensor, display, actuator, and / or other type of component mounted on substrate A. This substrate A is implemented from a material that is relatively rigid enough to mount the sensor, display, actuator, etc. of component X, for example, as a medical or other biosensor, industrial sensor, etc., but is flexible and / or stretchable enough to conform to a subject's body, industrial equipment, parachute, clothing, or other flexible articles. Substrate A then moves to substrate B. This substrate B is implemented from a relatively more flexible and / or stretchable (e.g., highly elongated) material that extends over a certain distance and conducts one or more signals to component Y and / or acts as a sensor. For example, substrate B is sewn, glued, or attached to clothing, parachute cord, pipe, conduit, cable, etc. Substrate B then moves to substrate C. This substrate C is made of a relatively rigid material such as a glass fiber or polyamide circuit board, and for example, it houses a data acquisition unit and / or processing unit that displays data received from component X, transmits data displayed by component X, and controls one or more sub-components within component X.

[0071] Therefore, in some embodiments, depending on the details of the implementation, an assembly such as the one shown in Figure 11 provides a solution for complete end-to-end interconnection between two parts that span multiple joints between dissimilar materials traversing multiple environments, while utilizing a single continuous interconnection.

[0072] Some techniques used to manufacture continuous interconnects between dissimilar materials, as shown in Figures 10 and 11, relating to some of the inventive principles of this patent disclosure, include those disclosed in U.S. Patent Application Publication No. 2020 / 0066628, incorporated by reference. This publication discloses a method for directly mounting surface mount components to vias filled with conductive gels and other interconnecting media, and a stencil method for manufacturing multilayer PCBs that conform to conductive gels and other interconnecting media.

[0073] The embodiments disclosed herein are described in the context of various details of implementation, but the principles of this disclosure are not limited to these or other specific details. While some functions are described as being implemented by a given component, in other embodiments such functions may be distributed across different systems and components located in different places and having various user interfaces. While a given embodiment is described as having a particular component, process, step, or combination thereof, these terms also encompass embodiments in which a particular process, step, or combination thereof is implemented by multiple components, processes, steps, or combination thereof, or in which multiple processes, steps, or combination thereof are integrated into a single process, step, or combination thereof. References to a component or element may refer to only a part of that component or element. The use of terms such as “first” and “second” in this disclosure and claims is solely for the purpose of distinguishing what they modify and does not indicate spatial or temporal order unless evident from the context. Furthermore, a reference to a first thing does not imply the existence of a second thing. Furthermore, the various details and embodiments described above can be combined to produce additional embodiments relating to the inventive principle of this patent disclosure.

[0074] Since the inventive principle of this patent disclosure can be modified in arrangement and details without departing from the inventive concept, such modifications and alterations are considered to fall within the scope of the following claims.

Claims

1. circuit board and sealing layer, A wiring formed from a deformable conductor disposed between the substrate and the sealing layer, Pattern of conductive material, An interconnection section that electrically connects the wiring and the pattern of the conductive material, The substrate has vias that extend through it, The interconnection portion is formed from the deformable conductor, The vias form the interconnection portion, A deformable electronic device characterized in that the deformable conductor includes a material that maintains a fluid or liquid state.

2. The deformable electronic device according to claim 1, wherein the deformable conductor is a conductive gel.

3. The deformable electronic device according to claim 2, further comprising a stencil layer located between the sealing layer and the substrate.

4. The deformable electronic device according to claim 3, wherein the stencil layer comprises at least partially the deformable conductor.

5. The deformable electronic device according to claim 1, wherein the pattern of the conductive material is arranged on the substrate.

6. The deformable electronic device according to claim 1, wherein the conductive material is made of conductive silicone.

7. The deformable electronic device according to claim 6, wherein the pattern of the conductive material forms an electrode.

8. The deformable electronic device according to claim 7, wherein the electrode is an electrode for a bioelectric sensor.

9. The deformable electronic device according to claim 1, wherein the deformable conductor comprises a eutectic gallium alloy.

10. The deformable electronic device according to claim 1, wherein the substrate and the sealing layer are made of a common material.

11. Including additional layers, The deformable electronic device according to claim 1, wherein the additional layer is a fabric integrated into the wearable device.

12. A first layer made from a first material, Wiring formed from a deformable conductor arranged on the first layer, A second layer made from a second material, The wiring has an interconnection section which electrically connects the wiring to the second layer, The interconnection portion is formed from the deformable conductor, The deformable conductor further forms vias extending from the wiring to the second layer. The interconnection portion is located at the via, A deformable electronic device characterized in that the deformable conductor includes a material that maintains a fluid or liquid state.

13. The deformable electronic device according to claim 12, further comprising the sealing layer configured to seal the wiring between the first layer and the sealing layer.

14. The deformable electronic device according to claim 12, wherein the deformable conductor is made of a conductive gel.

15. The deformable electronic device according to claim 12, wherein the first material is an insulating material and the second material is a conductive material.

16. It further comprises a third layer made from a third material, The deformable electronic device according to claim 12, wherein the wiring is arranged between the first layer and the third layer, and the via extends between the first layer and the second layer.

17. The deformable electronic device according to claim 16, wherein the third layer is a fabric integrated into the wearable device.

18. circuit board and An electronic component arranged on the first surface of the substrate, Wiring formed from a deformable conductor disposed on a second surface opposite to the first surface of the substrate, A sealing layer that seals the deformable conductor together with the substrate, It has an interconnection part that electrically connects the wiring and the electronic component, The interconnection portion is formed from the deformable conductor, A deformable electronic device characterized in that the deformable conductor includes a material that maintains a fluid or liquid state.

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