Multi-layer structures having embedded sensing capabilities and related manufacturing methods - Patents.com

Abstract

To provide an integrated multilayer structure suitable for use in sensing applications.SOLUTION: A multilayer structure (100) includes at least one plastic layer (104), and at least one film layer (102, 102B) provided on both sides of the plastic layer. A film layer (102) on a first side of the plastic layer includes electronics (103, 110, 112, 114, 116) incorporating reactance sensing electronics for sensing of selected target quantities, and conversion thereof into representative electrical signals. The sensing electronics include an electrode and a connection element for connecting the electrode to control circuitry. The film layer (102B) on a second side of the plastic layer includes feature sections (105, 118, 120, 124, 126, 128) including one conductive feature section, the feature sections being configured to adapt the sensing response of the sensing electronics on the first side of the plastic layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] Generally, the present invention relates to electronics and related devices, structures, and methods of manufacture. Specifically, but not exclusively, the present invention relates to the manufacture of multi-layer structures that incorporate several features for sensing or other purposes. [Background technology]

[0002] A variety of different stacking assemblies and structures exist in connection with electronics and electrical products.

[0003] The motivations behind the integration of electronics and related products can be as diverse as the relevant use contexts. Size savings, weight savings, cost savings, or even efficient integration of components and related, potentially synergistic, functions may be pursued first, for which the resulting solution ultimately exhibits multi-layered nature. The relevant use scenarios may then concern product packaging or food casings, visual design of device housings, wearable electronics, personal electronic devices, displays, detectors or sensors, vehicle interiors and electronics, antennas, labels, etc.

[0004] Electronics, such as electronic components, ICs (integrated circuits), and conductors, can generally be provided on substrate elements by a number of different techniques. For example, prefabricated electronics, such as various surface mounted devices (SMDs), can be attached onto substrate surfaces that ultimately form the inner or outer interface layers of the multi-layer structure. In addition, techniques that fall under the term "printed electronics" can be applied to actually manufacture electronics directly and additively on the substrate concerned. The term "printing" in this context refers to various printing techniques that can produce electronics / electrical elements from printed matter, including but not limited to screen printing, flexography, lithography, and inkjet printing, through a substantially additive printing process. The substrates used can be flexible, but not necessarily, organic printed matter.

[0005] The concept of Injection Molded Structural Electronics (IMSE) actually involves building functional devices and components therefor in the form of multi-layer structures that encapsulate electronic and possibly other functions.

[0006] In the IMSE process, different features of the desired functionality may first be applied to a substrate film, which may then be inserted into an injection molding cavity, and material in a hot molten state is injected onto, or in some cases between, the films, thus becoming an integral part of the resulting multi-layer structure.

[0007] One interesting property of IMSE is that electronics are often, but not always, also manufactured in 3D (non-planar) form according to a 3D model of the target product, part, or generally the entire design. To achieve a desired layout of electronic or other elements on the substrate and in the associated end product, the electronics may still be provided on an initially planar substrate, such as a film, using two-dimensional (2D) methods of electronics assembly, and then the substrate already housing the electronics may optionally subsequently be formed and overmolded into a desired three-dimensional, i.e., 3D, shape, for example, by a suitable plastic material that covers and embeds the underlying elements, such as the electronics, thus protecting and potentially hiding the elements from the environment.

[0008] In some usage scenarios, space constraints limit the amount and nature of functionality that can be integrated into a multi-layer structure, including an IMSE structure.

[0009] For example, various functional features integrated into a common structure may require a significant amount of space, such as a mounting surface, firstly to accommodate the associated physical element or elements and secondly to simultaneously maintain the necessary distance between other features, as is advantageous in reducing mutually induced or externally coupled noise and thus improving the signal-to-noise ratio, so that inaccurate, unreliable or otherwise non-optimal operation, such as, for example, erroneous measurements or so-called false positives (false detection of user input), may be avoided in different applications involving sensing solutions.

[0010] Integration of these two feature types in particular can be challenging, since there may be noisy features that cause electromagnetic interference in the environment, while there may also be features whose proper operation is particularly sensitive to disturbances. Compensating for a noisy environment with increased size of sensitive features obviously leads to even greater space consumption-related problems. In some cases, some of the integrated features, such as electronic features, should remain closer to the external environment, such as the environment of use of the integrated structure, while it is beneficial to place some other features closer to, for example, a host device or host structure that houses or connects to the multi-layer structure, and thus successfully combining such objects can be cumbersome, if not impossible, especially in conjunction with conventional, planar, rigid electronics designs and limited space, where only complex shapes are available to incorporate features.

[0011] In some cases, by certain design choices such as the use of low-noise electronics (e.g., linear LED drivers instead of switched ones), the magnitude of the disturbances caused can be reduced at the expense of other factors such as energy efficiency, heat generation, battery life, reduced functionality (e.g., no LED dimming). In some scenarios, the operation of several features intended to jointly establish a functional ensemble further suffers from suboptimal distances between them, such as being too short. In some scenarios, several electrically functional conductive features are overlapped, which requires, for example, the use of a dielectric layer as an intermediate layer. Thus, while the number of processing phases may increase considerably, different undesirable problems such as crosstalk may still appear, and the physical layout design of the structure may also ultimately be subject to many troublesome limitations, potentially negatively affecting the overall usability of the resulting product. Moreover, when features are densely packed, problems arising from their malfunction and thermal management also easily become real problems.

[0012] In some usage scenarios, deflection of the material may be desired, for example to increase the sensitivity of self-capacitive or force-sensing solutions, and therefore cavities may be included in the structure to allow for such. However, the use of cavities may raise various issues, such as material compatibility issues and a tendency to separate integrated structural layers from one another.

[0013] Furthermore, certain materials, such as metals or other highly conductive materials, cannot be utilized as top layers because they may effectively interfere with the correct functional operation of the underlying functional features, which accordingly place limitations on the aesthetic and visual properties of the structure that may well establish an exterior or otherwise visible, potentially tangible surface in a myriad of end products.

[0014] Yet, for example, in different sensing solutions, electric, magnetic, or generally electromagnetic fields may be generated and measured to detect the quantity and quality of selected targets. However, the controllability of the strength, size, shape, and alignment of such fields may remain poor, which also negatively affects, for example, the spatial sensing resolution and the effective signal-to-noise ratio achieved. Shielding from external electrical disturbances or different physical or chemical phenomena may furthermore be difficult. Moreover, effective power distribution poses problems in many scenarios, for example, due to the limited electrical conductivity of additively manufactured conductor materials.

[0015] Furthermore, in some instances it has proven tricky to include several conductively, e.g. galvanically connected layers, or features in general, in a common structure, since precise positioning and alignment of the features themselves or the required connection elements is difficult and the obtained connection quality, such as electrical connections between multiple layers, may remain somewhat suboptimal. Summary of the Invention [Problem to be solved by the invention]

[0016] It is an object of the present invention to at least alleviate one or more of the above-mentioned disadvantages associated with existing solutions in the context of integrated multi-layer structures and functional elements or features, such as electronics, embedded therein. [Means for solving the problem]

[0017] The objective is achieved by various embodiments of the multi-layer structure and associated manufacturing methods according to the present invention.

[0018] According to one embodiment of the present invention, an integrated multi-layer structure suitable for use in sensing applications such as fluid, surface level or flow sensing, optionally in touch, proximity or specifically gesture, force, pressure, strain, material, comprises: at least one plastic layer, optionally comprising a substantially electrically insulating material, e.g., a molded or cast layer, having a first side and an opposing second side; at least one, optionally plastic, film layer provided on both a first side and a second side of the at least one plastic layer, e.g. one or two film layers on each side; At least one film layer on a first side of the at least one plastic layer advantageously comprises electronics incorporating reactance sensing electronics for sensing, optionally capacitive and / or inductive sensing such as predicted capacitance, of one or more selected target quantities or in particular qualities, optionally indicative of touch or proximity of an external object to the structure, and conversion thereof into a representative electrical signal, the sensing electronics for reactance sensing comprising at least an electrode and preferably a galvanic connection element for connecting the electrode to an associated control circuit, preferably driving the at least one electrode, the structure optionally hosting at least a part of the control circuit, At least one film layer on the second side of the at least one plastic layer comprises one or more features including at least one (electrically) conductive feature, the one or more features configured to adapt the sensing response, optionally sensitivity and / or directionality, of sensing electronics on the first side of the at least one plastic layer.

[0019] In various embodiments, at least one film layer on the first side of at least one plastic layer is made of or at least includes an electrically insulating material. It may include plastics, such as thermoplastic films, and / or various other films or materials discussed below. In addition, it may include conductive materials. Furthermore, it may host insulating and / or conductive materials on either or both surfaces, for example, in the form of one or more coatings, optionally additively manufactured printed or otherwise configured features thereon, transferred (e.g., tape-based) features, laminated additional films, attached features, etc.

[0020] In various supplemental or alternative embodiments, the sensing electronics comprises one or more elements, such as electronic components, fabricated, optionally printed, deposited, coated, and / or attached onto at least one film layer, optionally on a first side of the at least one plastic layer.

[0021] In various supplemental or alternative embodiments, at least one electrode of the sensing electronics defines an electrode pattern, with elements of the electrode pattern being provided in one or more layers on one side or on opposite sides of the at least one film layer on a first side of the at least one plastic layer.

[0022] In various related embodiments, the pattern includes a mutual capacitance sensing pattern of multiple transceiver electrodes, or a self-capacitance sensing pattern of multiple sensing electrodes and, optionally, a reference (pattern).

[0023] In various complementary or alternative embodiments, the at least one film layer includes a first film on a first side of the at least one plastic layer and a second film on a second side of the at least one plastic layer.

[0024] In various complementary or alternative embodiments, the structure comprises a film, a first section of the film defining at least a portion of the at least one film layer on a first side of the at least one plastic layer, and a second section of the film defining at least a portion of the at least one film layer on a second side of the at least one plastic layer, the first and second sections being connected by a third section extending between the two, the third section optionally hosting one or more, preferably printed, conductors thereon that extend between and electrically connect the first and second sections.

[0025] In various supplemental or alternative embodiments, the one or more features include at least one conductive or insulating functional element, such as a patterned shape on the second side of the at least one molded plastic layer, that is locally defined by the material of one of the at least one film layers.

[0026] In various supplemental or alternative embodiments, the one or more features include a conductive material that constitutes at least a portion of a film of the at least one film layer on the second side of the at least one plastic layer, the film optionally being of substantially uniform or non-uniform composition.

[0027] In various supplemental or alternative embodiments, the one or more features include at least one electrically conductive and / or thermally conductive or insulating element defined by additional electrically conductive or insulating material, optionally printed or coated, on a film of the at least one film layer on the second side of the at least one plastic layer, where at least one of the at least one element is optionally defined on a side of a film of the at least one film layer on the second side of the at least one plastic layer facing the at least one plastic layer or on a side opposite the at least one plastic layer.

[0028] In a related embodiment, the elements extend locally onto the film, for example to define a pattern thereon, or alternatively, the elements extend onto at least one side of the film, over a major portion or substantially the entire surface thereof, optionally as a coating, such as a metal coating or plated layer.

[0029] In various supplemental or alternative embodiments, the structure, e.g., one or more of the features described above, comprises a colored conductive material, optionally a pigment or dye colored paint or ink, the material optionally comprising silver, salt, precious metal, carbon nanotubes, carbon nanobuds, or conductive polymers on a film of the at least one film layer on the second side of the at least one molded plastic layer, the material optionally configured to define graphic features such as symbols, numbers, letters, pictures, area or button shapes, geometric shapes or text of a decorative and / or informational nature.

[0030] In various supplemental or alternative embodiments, the one or more features of the structure, for example, include at least one feature located adjacent to a predefined sensing area or volume established by at least one electrode and a further electrode or reference (e.g., ground) pattern provided within the structure, and / or located at least partially overlapping a conductive trace of the sensing electronics;

[0031] At least one feature defines at least one functional element selected from the following group: a. an electromagnetic shield, such as an EMI or ESD shield, for shielding a sensing area, volume, or trace from external or internal electromagnetic disturbances or interference, the shield optionally being floating, earthed, or connected to a circuit ground; and b. An electromagnetic or electric field adjuster for adjusting the sensitivity of the sensing volume, optionally directional, optionally actively by dynamically inducing a current or potential into the sensing volume as controlled by the control electronics.

[0032] In various supplemental or alternative embodiments, the sensing electronics and one or more features at least partially define one or more sensing areas or volumes on either side of the at least one plastic layer, and the structure further includes an intermediate film within the at least one molded plastic layer, the intermediate film being at least partially made of or provided with a conductive material that defines an electromagnetic shield or ground plane to reduce mutual electromagnetic interference between the sensing features on either side.

[0033] In various supplemental or alternative embodiments, the one or more features of the structure, for example, defined above, define at least one element selected from the group consisting of an electrode or electrode pattern configured to establish a mutual capacitance sensing configuration with at least one electrode of the sensing electronics, an electrode or electrode pattern on a side of a film of the at least one film layer on the second side of the at least one plastic layer facing the at least one plastic layer and configured to establish a mutual capacitance sensing configuration with at least one electrode of the sensing electronics, a contact or non-contact sensing area, an NCVM coating, an electroless plating based coating, a PVD coating, a capacitively coupled electromagnetic or electric field adjuster, a parasitic coupling based sensing feature, a reference electrode, an actively or passively coupled reference plate, a ground electrode, and a floating ground, an earth connection, or a circuit ground connected ground electrode.

[0034] In various supplemental or alternative embodiments, the at least one plastic layer optionally includes a volume of elastic material, with a dielectric constant equal to or exceeding a selected threshold value, such as about or more precisely 5, and / or substantially exceeding the dielectric constant of other, e.g., primary, materials of the at least one plastic layer, the elastic volume being locally provided above at least one electrode of the sensing electronics and / or below a predefined sensing area (and, e.g., its electrode) on at least one film layer on a second side of the at least one plastic layer, the volume being configured to compress in response to an external force applied through the at least one film layer.

[0035] In various supplemental or alternative embodiments, the structure includes a galvanic connection element, such as a conductive spring, contact stud, or flexible connection member, between the sensing electronics and one or more features, optionally provided by at least one conductive element extending through the molded plastic layer or around the edge or periphery of the structure.

[0036] In various supplemental or alternative embodiments, the structure includes at least one protective and / or decorative overlay layer over the at least one film layer on the second side of the at least one plastic layer, the overlay layer comprising at least one material selected from the group consisting of veneer, wood, textile, fabric, natural biomaterial, molding material, injection molding material, and plastic.

[0037] According to one embodiment, a method for manufacturing an integrated multi-layer structure for sensing applications comprises the steps of: Obtaining at least one, optionally plastic, film; configuring at least one film, optionally a first of the at least one film, with reactance sensing electronics for sensing one or more selected target quantities and / or qualities and converting same into a representative electrical signal, the sensing electronics including at least one electrode and preferably a galvanic connection element connecting it to an associated control circuit, preferably driving (controlling) the at least one electrode; and optionally further providing at least a portion of a control circuit, such as an integrated control circuit, in the at least one film; configuring at least one film, optionally a second film of the at least one film, with one or more features including at least one conductive feature, the one or more features configured to tailor a sensing response, optionally a sensitivity and / or directionality, of the sensing electronics, the configuring optionally including patterning the at least one film and / or adding material thereon, preferably by printed electronics techniques or by plating or other forms of coating; and disposing, optionally by molding or casting, at least one advantageously plastic layer, preferably comprising a substantially electrically insulating material, on the at least one film, and configuring the at least one plastic layer to define an intermediate layer, preferably substantially integrated, between the sensing electronics and one or more features hosted by the at least one film for adapting a sensing response, wherein at least one of the at least one film is optionally formed to assume a selected three-dimensional shape, and further optionally formed after providing it with at least a portion of the sensing electronics or one or more features.

[0038] Various considerations provided herein with respect to embodiments of multi-layer structures may be flexibly applied, mutatis mutandis, to embodiments of the manufacturing methods, and vice versa, as will be understood by those skilled in the art. Moreover, the various embodiments and associated features may be flexibly combined by those skilled in the art to come up with preferred combinations of features generally disclosed herein. The usefulness of the present invention arises from a number of issues, depending on the embodiment.

[0039] In general, different embodiments of the present invention enable the design and fabrication of customized functional ensembles that flexibly match different physical host structures with associated property-imparting forms, geometries, and materials.

[0040] The proposed multi-layer structure may comprise several functional layers, each provided with selected functional features, the layers / features advantageously having optimal spacing and optionally connections such as electrical connections between them, and the very different features may be effectively integrated together, for example on one or both sides of one or more included film layers, which may be present on either side of one or more intermediate layers, such as molded, cast or otherwise manufactured plastic-containing or other layers, while the operation of each feature may still be skillfully optimized in terms of multiple criteria such as (reduced) mutual or external noise coupling, or SNR (signal to noise ratio), noise tolerance, detection sensitivity, detection directionality, aesthetic, visual and optical considerations, item dimensions, weight, thermal properties and heat management.

[0041] In various embodiments, some features producing different functions or effects may be provided as overlays on different layers to optionally produce combined or synergistic effects, such as aesthetic, informational (e.g., guided / instructional), or sensing functions in combination with other visual or optical effects.

[0042] For example, embodiments that use two films or film layers on either side of a multi-layer structure, or generally on different locations of a component, device, or other type, to house electrical and other, possibly multi-purpose or common, features, can help alleviate many of the problems associated with single layer solutions, including, but not limited to, the following in any way: -switched LEDs, data bus traces and power circuitry, or other features considered to be noisy, which, if provided for example on a different film layer, may now be placed further away from more sensitive features such as capacitive sensors; - noise currents that cannot be efficiently coupled to other film layers when the ground plane has, for example, a star connection and no direct current loops pass through the second film; -Direct coupling of noise through slightly conductive materials (as mineral-filled inks tend to be, such as many black inks) can be virtually eliminated, allowing a wider variety of materials to be used for different purposes, including for example decoration and field shaping; - aesthetic or visual concerns: multi-layer solutions allow for example to use functionalized decorative graphic elements, for example also as capacitive sensors or antenna radiators. In addition, for example mutual capacitance sensors can be implemented in such a way that they are resistant to unwanted activation, for example via the back side or other intended passive side of the structure. For example, a TX hatch can be provided on a predefined back film, while the solution is still highly sensitive to touches on the front (intended activation) surface or direction, since the desired RX pattern can be provided on the respective surface(s); - General glitches / detection: having an extensive shield printed or otherwise manufactured to open only over the desired sensing area where touch sensitivity is required can be used to effectively mask "ghost" actuations and false detections on sensing circuitry such as electrodes or traces via each side. This shield, for example on the front side or user input side of the structure, can also be used as a "driven shield" and the system ground can be largely masked from coupling through water, making the system potentially highly resistant to glitches due to, for example, water; - spatial concerns and dimensional constraints: manufacturing (printing, dispensing, etc.) materials with different electrical or magnetic parameters on one, e.g. front, film can be used for field shaping, so that closely spaced sensing features, such as touch sensitive areas defining touch buttons, appear to be further away from the signal's point of view, or so that the manufactured structure is able to absorb the field and, e.g., limit the EMI emitted by the structure; and / or - Optimal functionality and manufacturing challenges: the use of shielding features, e.g., printed features, can be more meaningful or practical when the shielding can "flow over" the structure being shielded. Having both the shielding and the traces to be protected in a single layer is not as efficient as having them on top of each other without having to excessively, e.g., print dielectric between the wiring layer and the shielding, potentially ground load capacitance or other sensors.

[0043] In various sensing scenarios and embodiments, the present invention may provide improved sensitivity by providing features such as electrodes printed or otherwise fabricated on different overlapping layers such as films of a stack structure, preferably having between them a deformable or "soft" material, optionally associated with a high dielectric constant, to translate smaller external force induced (e.g., touch induced) deformations of the structure into a larger effect on the sensed mutual capacitance, or generally on the sensing quantity. The use of rather problematic gases, or specifically air filled cavities, to allow sufficient material deformation may be avoided or reduced.

[0044] In various embodiments, the reactive sensing techniques proposed herein, such as capacitive sensing, may in fact be provided by multilayer structures, even if they generally contain highly conductive surfaces, such as metals, while still eliminating the need for internal gases or specifically air-filled cavities that may cause undesired delamination of the structure. Effectively, for example, a touch-through metal type solution may be provided. Moreover, in view of manufacturing, the multilayer structures according to various embodiments of the present invention may be substantially established even by a single manufacturing process, instead of a complex combination of various required methods and post-processing steps. Furthermore, some materials, such as aluminum, are prone to permanent deformation when thin layers thereof are applied, and therefore, in the material stack of the present invention, the stack may be configured to act as a "spring" to prevent permanent deformation and thereby prevent loss of desired performance aspects. In general, the multiple layers of the multilayer structure may be manufactured using various lamination (heat, pressure, adhesive, chemical, physical, etc.), molding (e.g., multi-shot) and / or printing (e.g., printed electronics printing) techniques.

[0045] In various embodiments, the application of non-galvanically connected elements provided on one layer may be configured to shape the electromagnetic field established by electronics, such as sensing electronics, provided remotely on another layer, in favor of improved operation, such as sensitivity and directivity, as well as reduced noise sensitivity. Similar structures may alternatively be applied to provide capacitively fed antennas to improve efficiency and facilitate impedance matching, for example, between feeding and radiating elements.

[0046] In various embodiments, touch or gesture (non-contact) sensing functionality may be provided by the proposed structure, or panel in particular, by implementing therein multiple overlapping features, such as electrode patterns or generally multi-layered or multi-surfaced electrical layouts. For example, patterns may be provided on different, opposing surfaces of a common element, such as a film, and / or on multiple elements, such as films or other layers. Different functions may be flexibly superimposed to produce essentially separate or synergistic effects. For example, a multi-touch sensing configuration may be superimposed with lighting solutions, such as several LEDs, and / or light-guiding structures, such as graphics or other optical forms, for example, to allow for illumination or visualization of the sensing area. One film or layer may implement at least one function (e.g., using both sides / surfaces of the layer for a purpose), while another film or layer may be utilized for another, potentially synergistic, purpose.

[0047] The flexibility offered by multi-surface (mass) solutions and feature overlays in general may further be replaced by a reduced use of support features such as dielectric layers that may still suffer from defects such as crosstalk issues and / or require non-conductive ink traces to be overlaid where they are undesirable from an optimal electrical design perspective. Omitting unnecessary features, or specifically layers such as dielectric layers, from the entire structure would be advantageous in layout design, not only in terms of simplicity in general, but also in terms of electrical sensitivity, performance, and cost considerations. On the other hand, multi-layer and multi-surface designs, when beneficial, also allow for more efficient system-level or application-level integration, which may in fact be realized by the mutually compact placement of features such as electronic features. For example, system electronics such as controllers or integrated circuits may be placed closer to the sensing area.

[0048] In various embodiments, the multi-layer structure may incorporate several functional coatings provided according to the present invention (on the exterior of the structure and / or embedded in several interior surface(s) / interface(s)). Such coatings may find use in various usage contexts, such as different lighting applications, in addition to or instead of sensing. The functions may further include, for example, thermal management (the coating may include, for example, a material with a selected thermal conductivity or sufficiently high thermal insulating capacity for effective cooling of the structure or the features contained therein), electrical distribution (e.g., sufficiently high electrical conductivity), electrical shielding (e.g., conductive or insulating capacity), and / or light management (e.g., optical transmittance, reflectance at wavelengths of interest, such as visible light). Moreover, the coating may also have decorative / aesthetic and / or informative visual functions.

[0049] In various embodiments, in addition to providing, for example, optical or electrical transparency or conductivity, functional materials such as printable materials or generally pigmented or colored inks or paints may be applied to provide aesthetic, informational, or other visual features, such as symbol shapes or geometric shapes. For this purpose, the conductive inks or paints may be colored, for example, according to a desired color preference. Thus, underlying non-visual features may be hidden from the user without the need to provide additional masking features or to place the underlying features out of sight. Reducing the number of layers may then advantageously make the target multilayer structures simpler, which may facilitate and advance their manufacture.

[0050] As already mentioned above, in various embodiments, the present invention can be utilized in providing effective trace shielding for sensing, such as capacitive sensing, and other purposes. Shielding or specifically, for example, ground elements, can be provided from a conductive material layer using conductive hatches (cost-optimized fill ratio per target) or (printed) layers of conductive ink, which can also have decorative or other visual functions in multi-layer structures, among other possibilities. Thus, the size of the actual sensing features can be kept modest, for example to free up space for other uses, or simply to keep the structure compact, since noise problems and false couplings that cause ghost detection can be reduced.

[0051] In various embodiments, several layers of the structure may be established from a single element, such as a film, that is folded or generally bent to form such layers, while optionally still remaining integral, which makes it easy and possible to also provide desired connectivity, such as electrical, optical, and / or thermal conductivity between the layers, by means of connecting features, such as conductor traces, provided on the film and extending from layer to layer.

[0052] In various embodiments, a multi-layer structure having multiple simultaneously operable touch-sensing sides, or generally sensing surfaces, layers, regions, or directions, may be arranged such that mutual interference between associated sensing features is reduced and remains small. This is obtained by shielding, or specifically ground features, arranged between the sensing features, such as electrodes, and optionally provided on intermediate substrate layers, for example by printed electronics.

[0053] In general, the different embodiments of the manufacturing methods contemplated herein, notwithstanding their uniqueness and advantages over the prior art, remain relatively straightforward to understand and incorporate into use, without the need to employ complex trial-and-error manufacturing techniques, for example, to provide desired features selected for sensing or other purposes within the multi-layer structure.

[0054] Forming the film(s) into a desired 3D shape after providing features thereon, such as conductors or additional electronics, while the substrate film(s) is still substantially flat, at least in places, may further reduce or eliminate the need for potentially cumbersome and error-prone 3D assembly of electronics on the substrate film or other layers.

[0055] The resulting multi-layered structures can be used to establish desired devices or modules within different host elements, host structures, host devices or host entities, for example, with reference to vehicles or specifically vehicle (in-vehicle) electronics, lighting devices including vehicle lighting, user interfaces in vehicles and elsewhere, dashboard electronics, in-vehicle entertainment devices and systems, vehicle interior (e.g., doors, dash, center console, floor, wall, roof) or exterior panels, intelligent clothing (e.g., shirts, jackets, or pants, or compression clothing, for example), other wearable electronics (e.g., wrist-stop devices, headwear, or footwear), personal communication devices (e.g., smartphones, phablets, or tablets), and other electronics or items or systems that include electronics. The integration level of the resulting structures can be high and the desired dimensions, such as their thickness, can be small.

[0056] The film(s) and generally the material layers used may include graphics thereon, as well as other visually and / or tactilely detectable features, so that the film / layer may have an aesthetic (decorative) and / or informational function in addition to hosting and protecting, for example, electronics for sensing and / or other uses. The film(s) / layer(s) may be translucent or opaque, at least in places. They may exhibit a desired color or include portions that exhibit a desired color in the corresponding portion of the structure. Thus, the resulting multi-layer structure may optionally incorporate one or more colored / pigmented layers that determine graphics such as text, pictures, symbols, patterns, etc. These layers may be implemented, for example, by dedicated films of a particular color(s) or may be provided as coatings (e.g., by printing) on ​​existing film(s), molding layer(s), and / or other surfaces. The exterior film(s) of the multi-layer structure may be configured to establish at least a portion of the exterior and / or interior surface of the associated host product or host structure.

[0057] Various visible or visual features, such as graphic patterns, indicators, or colorings, may be provided below the exterior surface of the structure such that the features remain isolated and thus protected from environmental influences, at least by the thickness of the host substrate film and, optionally, for example, molded or cast layers, depending on which side of the film and on which film the features are provided for a particular environmental threat. Thus, different impacts, friction, chemicals, etc., that may easily damage, for example, painted, printed, attached, or otherwise provided surface features, do not affect or reach the features. Material layers, such as those defined by substrates or other films, may be easily manufactured or fabricated, and optionally cut, into desired shapes with properties such as holes or notches necessary to selectively expose underlying features, such as molded materials.

[0058] The term "some," as used herein, may refer to any positive integer starting with one (1).

[0059] The terms "plurality" may each refer to any positive integer starting with two (2).

[0060] The terms "first" and "second" are used herein to distinguish one element from other elements and do not impose any special priority or ordering thereon unless expressly stated otherwise or apparent to one of ordinary skill in the art.

[0061] When "different" or "various" embodiments of a multi-layer structure, related manufacturing methods, or features contained therein are referred to in this text, the embodiments are considered to be complementary to each other and therefore may also be realized in a common embodiment, unless otherwise expressly stated or obvious to a person skilled in the art that the solutions in question are clearly mutually exclusive alternative solutions for implementing the exact same features of the overall solution.

[0062] Different embodiments of the invention are disclosed in the accompanying dependent claims.

[0063] The invention will now be described in more detail with reference to the accompanying drawings. [Brief description of the drawings]

[0064] [Figure 1] 1 illustrates one embodiment of a multi-layer structure according to the present invention. [Diagram 2] FIG. 1 shows one further, complementary or alternative embodiment of the invention, in which several layers of the multilayer structure are established by a single film. [Diagram 3] 1 illustrates one embodiment of a force-sensing multi-layer structure according to the present invention. [Figure 4] 1 shows an embodiment of a multi-layer structure according to the invention with field shaping by use of an active / powered element and a functionally associated shaping element that is not galvanically connected to it. [Diagram 5]1 illustrates one embodiment of a multi-layer structure according to the present invention, for example for multi-touch sensing. [Figure 6] 1 illustrates one embodiment of a multi-layer structure according to the present invention having integral functional coating(s). [Figure 7] 1 illustrates one embodiment of a multi-layer according to the present invention with integrated shielding features such as trace shielding. [Figure 8] 4 illustrates a test scenario for trace shielding according to the present invention. [Figure 9A] 9 illustrates the electric field measured in the scenario of FIG. 8, where no trace shield features are implemented. [Figure 9B] 4 shows the electric field when trace shielding is present. [Figure 10] 1 illustrates an embodiment with multi-faceted or multi-directional sensing capabilities. [Figure 11] 1 shows a flow diagram according to one embodiment of the method of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] 1 shows in side (cross-sectional) view one embodiment 100 of a multi-layer structure according to the invention. The multi-layer structure 100 may establish an end product itself, e.g. an electronic device, or may be placed within or at least connected to a host, e.g. a host device, host system, or host structure, e.g. as an assembly component or module. It 100 may include several further elements or layers that are not explicitly shown in the figure for clarity.

[0066] The illustrated solution comprises at least two film layers 102, 102B and at least one intermediate material layer 104 of at least one material, such as plastic resin, optionally injection molded or cast, provided therebetween. The two film layers 102, 102B may be physically and, for example, electrically, thermally and / or optically connected through at least one layer 104 by several connecting members 108, such as springs (e.g., fairly rigid wires), contact studs, light guides, or similar structures bridging the gap between the films or specifically selected features thereon, such as conductive / contact pads, traces, and / or electronic components, and / or edges (via flexible interconnects, springs, staples, or similar methods), that allow the necessary connections. However, as will be apparent, the film layers or / and features thereon need not be physically connected in all embodiments, although they may still be functionally coupled to each other or affect each other's function.

[0067] In various embodiments, the film layers 102, 102B (note that there may be additional film layers in the structure) may comprise the same or different materials as each other. Similarly, the general structures of the layers 102, 102B may be similar or different from each other.

[0068] In various embodiments, the film layers 102, 102B may generally include or consist of one or more materials such as plastics, e.g., thermoplastic polymers, and / or organic or biomaterials, for example, wood, paper, cardboard, leather or fabric, or combinations of any of these materials with each other, or with plastics or polymers or metals.

[0069] Either of the layers 102, 102B may be visible to the environment of the structure 100, and they may even define the exterior of the structure 100, whereby they may have aesthetic / decorative or other visual functions, and possibly tactile functions (e.g., providing a desired feel with a selected surface roughness). Either of the layers 102, 102B may define or include holes, such as recesses or through-holes, for accommodating components or features, such as conductive vias.

[0070] For example, any of the layers 102, 102B may generally include or consist essentially of a thermoplastic material. Any of the layers 102, 102B may include a composite material. Any of the layers 102, 102B may include a coating on both sides thereof. Any of the layers 102, 102B may be essentially flexible or pliable, at least in places. In some embodiments, the film layers 102, 102B may be substantially rigid and stiff, at least locally. The thickness of each of the layers 102, 102B may vary depending on the embodiment and may be only a few tenths or a few percent of a millimeter, or may be substantially thick, for example, on the order of a millimeter or several millimeters. Any of the layers 102, 102B may be of constant or varying thickness and / or general structure.

[0071] Based on the foregoing, each or either of layers 102, 102B may comprise at least one material or materials selected from the group consisting of, for example, polymers, thermoplastic materials, electrically insulating materials, conductive materials, PMMA (polymethyl methacrylate), polycarbonate (PC), copolyesters, copolyester resins, polyimides, copolymers of methyl methacrylate and styrene (MS resins), glass, polyethylene terephthalate (PET), carbon fiber, composite materials, organic materials, biomaterials, leather, wood, cellulose, textiles, fabrics, metals, organic natural materials, solid wood, veneer, plywood, bark, tree bark, birch bark, cork, natural leather, natural textile or fabric materials, naturally grown materials, cotton, wool, linen, silk, and any combination of the above.

[0072] For example, in some embodiments, the film layer 102B may be essentially homogenous (e.g., a selected electrically insulating or conductive material, e.g., a metal sheet) that may still, for example, accommodate some additional features thereon, such as aesthetic / visual or generally optical, thermal, chemical, and / or electrical features. Alternatively, the film layer 102B may be heterogeneous in terms of at least one selected property or material, such as electrical conductivity. Thus, the mutually distinct portions of the layer 102B may define selected functionality or other features, such as electrodes or other sensing elements, electromagnetic shields, field shaping features for adjusting the response of, for example, capacitive or inductive sensing electronics provided on the layer 102, or other features.

[0073] The aforementioned at least one intermediate layer 104 refers to at least one layer of material that is initially provided, for example, directly on or between the film layers 102, 102B, by molding, such as injection molding, or casting, such as dipping, for example, the relevant material. Alternatively or additionally, the layer 104 may be disposed on the film layers 102, 102B, for example, as a prefabricated element, by laminating it thereon using, for example, mechanical adhesion, chemical adhesion, electrical adhesion, heat, pressure, solvents, and / or adhesives.

[0074] The at least one layer 104 may generally include several materials, such as polymers, organics, biomaterials, composites, and any combination thereof. The materials may include thermoplastic and / or thermosetting material(s). The thickness of the included layer(s) and other features, and thus the entire structure 100, may vary depending on the embodiment. It may be, for example, on the order of a millimeter, a few millimeters, or tens of millimeters. At least some of the materials of the at least one layer 104 may be, for example, electrically insulating or conductive. In some embodiments, the layer 104 may include at least one material selected from the group consisting of, for example, elastomeric resins, thermosetting materials, thermoplastic materials, PC, PMMA, ABS, PET, copolyesters, copolyester resins, nylon (PA, polyamide), PP (polypropylene), TPU (thermoplastic polyurethane), polystyrene (GPPS), TPSiV (thermoplastic silicone sulfite), and MS resin. The layer 104 may be of substantially homogeneous or heterogeneous structure.

[0075] There may be, at least locally, some further layers (e.g., coatings, further film layers, e.g., printed conductive layers defining circuit designs / traces or graphics), or generally speaking, features defined by or provided within and / or on the film layers 102, 102B, at least one intermediate layer 104 (on either or both sides and / or embedded), and / or elsewhere in the structure. Even if for clarity only a single feature is shown, e.g., as a rectangular or essentially square block in some particular locations in the figures, those skilled in the art will recognize that it may refer to or include multiple, mutually distinct and / or similar, features, such as traces, components, and / or circuits with other elements that may optionally be connected together, e.g., electrically (e.g., galvanically or capacitively), or otherwise, e.g., optically, or at least generally functionally.

[0076] These, potentially, still depending on the particular embodiment, included additional layers and / or other features 103, 105, 110, 112, 114, 116, 118, 120, 124, 126 may in fact be assigned various functions, such as protective, aesthetic, decorative, informational or other visual / optical functions, electrical functions, processing functions, control functions, memory functions, communication functions, sensing functions, (electromagnetic / electrical) field shaping functions, (e.g., electromagnetic / electrical) shielding functions, conductive functions, insulating functions, mounting or fastening functions, and / or spacing functions.

[0077] Provided features, such as spatially more extensive layers 103, 126, such as printed, coated, deposited, molded, or otherwise laminated layers, or more localized elements 105, 110, 112, 114, 116, 118, 120, 124, may each have their own dimensions, such as thickness (as shown in the figures), as well as characterizing materials. Alternatively, multiple features, such as layers 103, 103B, 103C, may have at least partially the same or similar configurations as one another, for example in terms of thickness or material.

[0078] Thus, the aforementioned features may include at least one element selected from the group consisting of, for example, electrical conductors such as traces, printed conductors, electrical insulators, electrical conductors, electrical circuit designs, contact pads, circuit traces, electrodes, electromagnetic shields, hatch shields, EMI (electromagnetic interference) shields, RFI (radio frequency interference) shields, electric or electromagnetic field shapers or attenuators, graphics, graphic ink layers, conductive ink layers, visual indicators, electrical elements, electronic components, integrated circuits, optical elements, light emitting elements, LEDs (light emitting diodes), OLEDs (organic LEDs), light detecting elements, lenses, light directing elements, light diffractors, light collimators, light reflectors, diffuse reflectors, specular reflectors, light guides, sensors, pressure sensors, proximity sensors, switches, piezoelectric elements, tactile elements, electromechanical elements, processing elements, antennas, memory elements, connectors, and communication elements.

[0079] In various embodiments, for example, one or more of the conductive features may include at least one conductive material selected from the group consisting of conductive ink, conductive nanoparticle ink, copper, steel, iron, tin, aluminum, silver, gold, platinum, conductive adhesive, carbon fiber, alloys, silver alloys, zinc, brass, titanium, solder, and any components thereof. The conductive material used may be optically opaque, semi-transparent, and / or transparent at desired wavelengths, such as visible light, and thus mask, or reflect, absorb, or pass radiation, such as visible light. In some embodiments, the conductive or insulating features defined in or on either the layers of the multi-layer structure or other features may have additional functions, such as aesthetic, informational, visual, or generally optical functions, such as masking functions.

[0080] One or more of the features may be directly manufactured on the multilayer structure 100, or on certain components thereof, such as film layers 102, 102B, using printed electronics techniques, such as screen printing, flexography, gravure, offset lithography, or inkjet. Alternatively or additionally, etching or applicable coating methods, such as silver or flow coating, may be used. As a further option, prefabricated features may be attached to the structure, for example, using adhesives, heat, and / or pressure, optionally in the form of a selected lamination method. As yet another option, one or more features, such as conductive traces, components, thermal conductors, and / or other elements, may be provided on the film layers 102, 102B, or on an at least partially pre-prepared carrier, such as a tape (e.g., an adhesive tape, or specifically, an adhesive transfer tape), which is then generally placed on the structure 100.

[0081] In various embodiments, one or more of the included layers and / or further, e.g., more localized features, may be at least partially optically substantially opaque or at least translucent, taking into account a given wavelength, e.g., the visible spectrum. These items may further be provided with visually distinguishable decorative / aesthetic and / or informational features, such as graphic patterns and / or colors thereon or therein. In general, IML (in-mold labeling) / IMD (in-mold decoration) techniques are applicable for such manufacturing. The items may be at least partially, i.e., at least in places, optically substantially transparent to radiation, e.g., visible light, emitted by electronics in the structure or other electronics on the structure. The transmittance may be, for example, about 75%, 80%, 85%, 90%, 95% or more.

[0082] In various embodiments of structure 100, the included features may include electronics, such as control electronics and / or specifically sensing or measurement electronics, provided in at least one layer, such as film layer 102, of structure 100.

[0083] For example, items 103, 105 on layers 102, 102B may each include a circuit design including at least conductive traces (alternatively or additionally, similar features may be present on the opposite side of layers 102, 102B, but are omitted from the figures for clarity), item 114 may include electronic components, such as integrated control circuitry or other control / measurement electronics, and item 116 may include sensing elements, such as electrodes, discussed in more detail below. Items 110, 112, 120 may represent, for example, further components, sensing elements, or connection features, such as connectors to an external system or, for example, a host device. Item 118 may include, for example, a shielding feature, and item 126 is a top protective, decorative, graphics-containing, masking or optically translucent / transparent, informational, or otherwise meaningful functional layer.

[0084] In some embodiments, layer 102B may represent or at least be located closer to the intended backside of structure 100 from the perspective of a user or environment of use (e.g., a target sensing volume or area) that interfaces with or is at least closer to layer 102B, and thus the backside may optionally be located closer to, and potentially even attached to or otherwise integrated with, a host device or structure, such as a host device, surface, or panel within a vehicle (e.g., an interior panel on the dashboard, a door, a center console, etc.), or some other host structure. However, in other embodiments, the situation may be reversed (i.e., layer 102B may be closer to the user / environment of use), or structure 100 may face the user or environment of use from multiple directions.

[0085] The aforementioned electronics may in fact include, for example, a control circuit(s) or control circuitry for sensing purposes and / or other uses. At the very least, the included electronics preferably includes several sensors or sensing features, for example in the form of several electrodes, which may be driven and / or measured by a control circuit, for example a circuit such as an integrated circuit and / or a circuit including separate connected components, via galvanic or wireless connections, the control circuitry may be provided within the structure 100, for example in the film 102, or may be present outside the structure 100 and connected to the structure via connecting elements such as (electrical) connectors and / or wires. The sensing features may be wireless, for example capacitive or inductive in nature. Sensing features such as electrodes may be controlled, for example, to establish an electric field, a magnetic field, or generally an electromagnetic field in the environment of the structure 100.

[0086] In various embodiments, any of the features of or on the film layer 102, such as feature 116, may include or define electrodes or other sensing elements for self-capacitance sensing. The elements may be configured (material, dimensions / location / distance, etc.) to define a selected parasitic (electrostatic) capacitance to a reference potential, such as a system or circuit ground, that is altered (increased) by an object, such as a user's finger, touching or hovering around the multi-layer structure 100, and that may be detected or measured by associated control electronics, for example, by measuring the time constant of an RC circuit comprising the electrodes. Thus, the elements may define, for example, a capacitive or specifically parasitic touch / gesture input area or volume, or a user input feature, such as a "button." To the user, the elements or associated sensing areas / volumes may be indicated, for example, using the formation of a surface area of ​​interest within the structure (e.g., a recess or protrusion, such as a dome or bowl shape) and / or a graphic or optical indicator (e.g., lighting). In various supplemental or alternative embodiments, preferably multiple features, e.g., features 116, 124 on different sides of layer 104, may define electrodes for mutual capacitance sensing, where the control electronics is configured to measure a change, such as a decrease due to an object, in mutual capacitance between at least two, first and second electrodes, at least one of which is a driven / transmitting electrode and at least another of which is a sensing / receiving electrode. Thus, feature 116 may define a first electrode on a first side of layer 104, while feature 124, for example, may define a second electrode on a second, opposing side within structure 100, both connected to circuitry of the measurement / control electronics.

[0087] In various embodiments, at least one feature, such as feature 118, may define a shield, e.g., an electromagnetic shield, such as a floating electromagnetic shield, an active (driven) shield, or a (system / circuit) grounded or earth-connected shield, for shielding the sensing electronics, associated circuitry, or underlying electronics, specifically circuit traces, from external electromagnetic fields or interference. For example, shielding for features, e.g., traces, circuits, or components 103, 114 on layer 102, may be provided by feature 118, which may define an area or volume of conductive material, optionally galvanically connected to a system / circuit ground.

[0088] In various embodiments, at least one feature (e.g., item 128) may define a field adjuster configured to vary a surrounding electromagnetic field (near-field) established, for example, by sensing electronics. The adjuster may be dynamically controlled by (active / driven) or passive electronics. It may be connected to an associated system ground or may be floating.

[0089] Thus, taking into account the aforementioned field adjustment type features and, e.g., shielding features of layer 102B, as well as electronics substantially in / on layer 102, layers 102, 102B may or may not need to be connected, e.g., electrically, such that the various features are galvanically connected to the same circuit, depending on the embodiment. Such connections, allowing, e.g., dynamic control, may be unnecessary when using, e.g., effective dielectric constant or, e.g., permeability, of the adjuster or shielding feature material to shape the field around a capacitive sensing element or antenna radiator.

[0090] In various embodiments, functionalized graphics may be utilized, i.e., conductive materials such as inks or paints may be added within the structure 100 for both decorative / aesthetic / informational and electrical purposes, including the formation of conductors such as circuit traces, contact pads, sensing elements such as (capacitive) electrodes or "capacitive buttons", sensor patterns such as electrode patterns, field shapers, shields, etc. For example, silver, carbon nanotube, carbon nanobuds, and conductive polymer inks may be fully functionalized in this aspect. The conductive ink may be supplemented therein with the desired colored ink. The desired color may generally be achieved in the material by the use of suitable dyes or pigments.

[0091] Many, if not most, conductive inks, for example, are more conductive than necessary to function adequately as touch sensing electrodes. Most conductive inks can also be at least slightly colored. The effect achievable depends on the distribution and appearance of the conductive material, as well as the extent to which the material can be diluted while retaining acceptable conductivity. "Diluting" conductive inks with colored inks can open up a whole new range of possibilities in producing interesting and attractive patterns and textures that serve both decorative and functional purposes. Coloring conductive inks allows for the dilution of relatively expensive materials, for example for large area shields, adjusters, sensors, and radiators / antennas printing, thus reducing production costs.

[0092] For example, when using functionalized graphic inks or similar substances, shielding, capacitive touch or other sensing electrodes, antennas, antenna resonators, etc. can be hidden, masked, or camouflaged from the external viewer while still being located near the external surface. Even complex sensor patterns can be "hidden in plain sight," making visually interesting features available to the designer. Thus, the implemented functionality can become virtually invisible, at least to those who do not know exactly what to look for.

[0093] The layers and other features can be occluded from both sides while appearing to have a uniform coloration, with only visual cues required for user interaction visible, or possibly only activated when the user approaches the surface, e.g., with reference to printed contours or other indicators indicating the location of the sensing area or generally the sensing feature, or a light source, e.g., on an underlying layer, configured to dynamically illuminate the sensing area (turning on when waiting for sensing input / when the sensing function is active, or e.g. blinking).

[0094] As a related example, touch pad or other touch area sensing electrodes may be printed on a surface such as layer 102B in a geometric shape or desired shape such as a spreading vine pattern. Having the sensor pattern very close to the outside or generally the target sensing surface may be beneficial in terms of sensing performance (sensitivity, directionality, etc.) in various usage scenarios.

[0095] As a further example, a selected conductive ink or paint, e.g., black ink, may be configured to establish visually identifiable features such as graphic patterns, while it may further be used to shield underlying sensing electronics, such as traces, from ghost touches, i.e., false detections, and / or to shape the electromagnetic field around, e.g., a touch button or other sensing feature. The black ink may be patterned such that the resulting isolated patches form parasitic resonator-type antenna elements (shapers) to affect the fields established or sensed by the underlying electrodes.

[0096] Thus, antenna resonators or other functional features may generally be hidden, for example, within geometric or other visible patterns detectable on the film layers 102, 102B when using conductive inks.

[0097] In various embodiments, providing electrical connection to the colored conductive ink pattern or similar features may be configured through connecting features or contacts, such as openings in an intermediate layer 104 or an adjacent layer, such as the host film layer 102, 102B, of contact features such as traces. The contacts may be hidden within the pattern.

[0098] One viable option is to add a strongly pigmented ink to a conductor ink with similar chemistry and solvents. Some conductive inks are derivatives of fairly filled (typically black or white) graphic ink formulas, some are fairly customized and more difficult to add color to. In these cases, adding dry pigments with ink-specific solvents to restore flow properties may be appropriate.

[0099] While screen properties associated with screen printing, for example, can be optimized by testing as desired or necessary, consideration of providing a colored conductive material, such as an ink, on a target surface, such as the film 102, 102B, need not be substantially different from providing any ink, or specifically printing it. Colored conductive inks may be successfully used, for example, in applications where conductivity is not of utmost importance, so that print quality may be correspondingly optimized for visual quality rather than conductivity.

[0100] Although the multi-layer structure 100 is shown as a rectangular stack, for example, the film layers 102, 102B may be formed (after or before providing features such as electronics thereon) to exhibit a desired 3D shape using, for example, thermoforming or cold forming, and then additional layers, such as intermediate layer 104, may be provided such that the multi-layer structure 100 may define a variety of shapes, generally or locally.

[0101] The various characteristics and features of the more general or potentially multi-purpose multi-layer stack 100 described above may be freely and selectively adopted in any of the more specific or dedicated embodiments described below, or vice versa, as will of course be readily understood by those skilled in the art. Moreover, the following description of the various embodiments is created to describe certain selected aspects in relation to the present invention, and thus the relevant disclosure may still lack features that are not essential from the perspective of understanding the specific aspects. However, such features are still entirely possible and in many cases advantageous to include in the relevant disclosed multi-layer structures even if not explicitly disclosed, as will also be readily understood by those skilled in the art (e.g., if electronics are included in the multi-layer structure, it may be well advantageous to provide them with external electrical connections, "system connections", etc., using appropriate connecting members such as connectors, wiring, internal connection features, etc.). Moreover, the features and characteristics of the following embodiments may be selectively combined with one another by those skilled in the art to come up with further embodiments in which the functionality underlying the features is preferably provided by a common multi-layer structure.

[0102] FIG. 2 shows a multi-layer structure 200 that is simplified from that of FIG. 1 for clarity, but one skilled in the art will recognize that structures 100 and 200 may be substantially similar to one another, or even different, in terms of the layers and other features included, materials used, dimensions, etc., with at least one difference resulting from the structure of film layers 102 and 102B.

[0103] As already mentioned above, in some embodiments, instead of using separate films for the layers 102, 102B, a common substrate film 102C may be folded or bent, as also shown in the figures by the dashed lines around its perimeter, to define several layers 102, 102B in a multi-layer stack (layer 102B may be considered to be formed from an extension of substrate 102A, or vice versa). The connecting intermediate portions may remain in the structure or may later be at least partially processed and / or removed, for example by cutting.

[0104] The connecting intermediate portion may include or be provided, optionally by printing, conductive features such as traces for electrically connecting the film layers 102, 102B with their electrical features, such as traces, circuit designs, sensing elements and components. Multiple film layers, at least originally established from a common film, may ultimately be provided on the same and / or different sides of layer 104 in the multi-layer stack 200. As shown at 108 (FIG. 1), layers 102, 102B may optionally be further connected together by conductive vias provided through an intermediate layer, such as layer 104, and / or using preferably conductive feature(s) for other connections.

[0105] With the illustrated solution, potential non-planarity and connectivity problems that arise from the use of separate connecting components such as springs and pins to connect layers 102, 102B may be substantially eliminated.

[0106] Features such as electrical features (traces, electrodes, etc.) or even electronic components may first be provided on any side of the film 102C, optionally by printed electronics techniques, and the film 102C may then optionally be shaped, such as by thermoforming, cut and / or bent to exhibit a desired three-dimensional shape, before providing at least one layer 104 therebetween, for example by injection molding or casting.

[0107] In some embodiments, the intermediate portion may be shaped, e.g., cut, to a reduced width, e.g., relative to layer 102, 102B, or generally to structure 100, 200, e.g., to accommodate printed conductors, but to reduce the amount of unused space. In some embodiments, a more versatile bend of film 102C may be performed, for example, to establish three layers of structure 200 therefrom (an "S" bend having an upper layer, a middle layer, and a lower layer).

[0108] FIG. 3 illustrates one embodiment 300 of a force-sensing and, for example, touch-sensing multi-layer structure according to the present invention having improved sensitivity.

[0109] Essentially as background information, it can be mentioned that it is rather typical for many self-capacitive sensing solutions, for example, that a relatively high degree of deflection of the cover material is required to cause a sufficient pressing effect in terms of sensing functionality. This issue can be addressed by including structural deformation-promoting cavities within the multi-layer stack, as mentioned above. However, air-filled cavities can increase the peeling sensitivity of the structural layers of the stack. Moreover, as another potential issue, the use of, for example, a metal overlay, or generally a top / top layer, which may be preferred for appearance, feel, or for example durability reasons, can substantially completely impede the operation of the underlying self-capacitive sensing solution.

[0110] Thus, in the illustrated embodiment, the desired level of material deflection in response to an external force F directed at a sensing location of the structure 300 to favor enhanced sensing sensitivity is obtained by at least one volume of more elastic or "softer" material 304 provided beneath a dedicated sensing location or sensing area 310 (indicated by dashed lines) embedded between or within other less elastic material surrounding the intermediate layer 104 between the film layers 102, 102B, such that the structure locally compresses in response to an external force applied to the structure 300 toward the interior of the structure substantially at the location of the sensing area 310 and the underlying material 304.

[0111] Even small deformations 312 can be translated into easily detectable changes in mutual capacitance between electrodes 305, 306 disposed on opposite sides of the material 304, which may have been printed, for example, using printed electronics techniques or some other manufacturing method on the film layers 102, 102B, one of which preferably acts as a driving / transmitting electrode and the other as a sensing / receiving electrode. Since the measured signal is proportional to the force used, rather than touch as simply a binary detection, an amount of force can be measured and the solution can be used as an analog force sensor instead of or in addition to a "simple" touch sensor.

[0112] The electrodes 305, 306 may be galvanically connected to corresponding drive and measurement circuitry, for example using traces and conductive via(s) through material layers (not shown for clarity) and / or the solution of Figure 2. Those skilled in the art will recognize that instead of an isolated electrode and a single (small) volume of material 304, multiple electrodes or electrode patterns, for example for grid-type sensing, respectively, may be implemented.

[0113] The solution is also applicable if a conductive element, such as a metal sheet 308, is provided on the film 102B and at least partially covers the sensing area 310. Thus, a touch-through-metal function can be implemented.

[0114] Material 304 may be selected to have a relatively high dielectric constant, for example, greater than about 5 and / or greater than that of material 104, to enhance touch / force sensing sensitivity.

[0115] In some embodiments, instead of or in addition to capacitive sensing, two opposing inductive loops may be configured at 304, 306, for example, for inductive sensing.

[0116] 4 shows at 400 one embodiment of a multi-layer structure according to the invention, comprising field shaping by use of active sensing or "feeding" elements and, optionally, functionally associated shaping elements that are not galvanically connected to the active elements. This solution is suitable for example for touch and proximity (non-touch / non-contact) sensing purposes.

[0117] The film layer 102 may be provided with control and / or sensing or measurement electronics, such as associated circuitry or circuits 406, preferably galvanically connected 405, e.g. via traces, arranged on the layer 102, optionally printed by printed electronics techniques, to, e.g. capacitive or inductive sensing elements 404, defining several electrodes (at least a part of such circuitry / circuitry may be extended to and connected to the structure 400 using suitable connecting elements such as wires). The other side of the intermediate layer 104 is provided with at least one field shaping element 408, such as a conductive element comprising a metal or other conductive material in the layer 102B, defined for example by the material of the layer 102B or provided thereon using, for example, an applicable printing (e.g. suitable method applicable to printed electronics techniques), deposition, lamination or coating technique.

[0118] By disposing the shaping element(s) 408 (if multiple, at least some of which may, for example, be galvanically connected together and / or remain separate) at a distance from the sensing element 404 on different planes, as in the illustrated example, the electric or electromagnetic field, or specifically the near field, established by the element 404, which may be considered a near-field antenna, may be flexibly controlled, such as attenuated, boosted, shaped, and / or oriented, to provide desired sensitivity characteristics for sensing purposes, e.g., touch sensing given a predefined touch area defined on layer 102B and / or proximity sensing given a sensing volume on layer 102B.

[0119] In addition to or instead of more "passive" field tuning provided by material selection, shape, dimensions, placement, etc. of the element(s) 408, at least one of the shaping elements 408 may be actively or dynamically controllable. Such controllability may be provided to the element 408, for example, by galvanically connecting it to electronics 406 within or external to the structure 400.

[0120] Thus, voltage and / or current can be supplied to element 408 to control in-situ shaping characteristics as desired, for example based on finding an application specific sweet spot by a thorough testing process with field measurements. Several layers of a multi-layer stack and / or features thereon can generally be connected together, for example, either through the stack / intermediate layers using conductive materials, or by the solution of FIG.

[0121] In some embodiments, gigahertz frequency range operable antennas, such as Bluetooth® antennas, may be fabricated in a multi-layer structure following similar principles, providing an antenna feed element (typically galvanically connected to a control circuit) and a remote / separate radiator, which may be wireless, such as capacitively coupled to a feeder. The resulting antenna structure may be very thin and flexible, and suitable for use in a variety of applications, such as wearable electronics. Impedance matching between the feeder and the radiator may be achieved by appropriately designing the wireless coupling between them, without having to rely on separate matching components.

[0122] FIG. 5 illustrates an embodiment 500 of a multi-layer structure in accordance with the present invention for multi-touch sensing.

[0123] Among various other options, at least one constituent electrode pattern, such as a line or, for example, a diamond pattern, is provided on both sides of the film layer 102, one 510 on the side or surface facing the layer 104 and another 508 on the opposite side or surface facing the environment of the structure, e.g., a host structure or device, or its additional material layers (not shown). These constituent patterns, which may be different or similar to one another, for example, in terms of the shapes used, their dimensions, spacing, materials, alignment, and / or orientation, together establish a desired overall sensing pattern, such as an XY grid of columns and rows, where the columns and rows may be mutually perpendicular (as suggested in the figure by the "ends" of the lines indicated at 508 and the longitudinal side contours of the outermost lines of 510) or may be arranged in some other configuration.

[0124] Alternatively or additionally, other surfaces or layers of structure 500 may be utilized to carry electrode patterns of a multi-touch capable sensing configuration. For example, film layer 102B may carry electrode patterns 510 or 508 instead of layer 102. In some embodiments, three, four (e.g., on both sides of both film layers 102, 102B) or more overlaid patterns may be provided within structure 500.

[0125] In various embodiments, patterns 508, 510 are configured for capacitive sensing, such as capacitive touch or multi-touch sensing. Such touch input may then be used to control, or specifically, for example, activate and deactivate, different functions of structure 500, a host structure, or, for example, an external device.

[0126] Control electronics 506, such as measurement or circuitry, may be connected to the pattern using, for example, conductor traces or other, typically conductive, elements 505, optionally printed, for example using printed electronics techniques. Alternatively or additionally, at least a portion of the electronics 506 may be external to the structure 500 and connected thereto using applicable connection elements, such as conductive traces.

[0127] In various embodiments, the structure 500 may be provided with several additional features that may be aesthetic, decorative, informational, other optical (light directing or manipulation) features, electrical features, thermal management features, lighting features, etc. For example, in the illustrated scenario, several features 512 on either or both sides of or embedded within the film layer 102B, or defined by the film geometry and / or material, may include, for example, decorative, informational, lighting (e.g., light sources, waveguides, etc.) features, and / or other (functional) features that are optionally overlaid on the underlying sensing features 508, 510, for example, to contribute to the sensing configuration by illuminating the sensing area on layer 102B.

[0128] Arranging several film layers 102, 102B and potentially other layers in a structure facilitates the integration of various features in the structure, keeping their distances large enough in view of reducing mutual interference or otherwise optimizing their function. Several layers of a multilayer stack can be connected together, for example through the stack / intermediate layers using conductive materials or, for example, by the solution of FIG.

[0129] FIG. 6 shows at 600 an embodiment of a multi-layer structure incorporating at least one integral functional coating in addition to the sensing function. However, it is worth noting that the solution may be utilized alone or in other contexts without the need to specifically include the sensing feature in the structure. The coating may have other optical functions such as aesthetic, decorative, informative, and / or reflective functions. Moreover, it may have several additional functions including protective, electrical, thermal, etc. Thus, a multi-functional coating may be provided to the structure 600. Thus, the coating may be considered in some embodiments to establish its own characteristics or to establish part of several other, potentially collective, characteristics to provide a desired quality.

[0130] In the illustrated example, the structure 600 is provided with, for example, a thermally and / or electrically conductive coating 608 on the film 102, optionally as a post-processing task, although coatings may alternatively or additionally be provided on other surfaces and generally elements of the structure 600, as illustrated by item 608B, depicted using dashed lines and defining the exterior of a sidewall of the structure 600, for example adjacent the plastic layer 104. Indeed, the coatings may generally define one or more interior layers and / or exterior surfaces of the structure. In some embodiments, most, if not substantially, of the entire exterior surface of the structure 600 may be provided with one or more coatings.

[0131] For example, the coating 608 may include a conductive material such as a metal, which may be configured to provide electrical connections (e.g., power, communication, and / or control) to certain electronic features 606, 606B, such as light sources (e.g., LEDs) or other components disposed on the structure, such as the film 102.

[0132] It 608 may be in direct electrical contact with the features 606, 606B, or there may be intermediate conductive features, such as conductive vias, traces, rivets, springs, studs, rods, etc., disposed within the structure 600 (note the vertical dashed lines). The conductive plating may be patterned (masked, post-deposition processing) to better suit current carrying uses, for example, and to allow at least a portion of the plating to be utilized as an additional functional element, for example an antenna resonator, sensing electrode, field shaper, shield, etc. The film layer 102B may define or host some features that are not shown in the figure for clarity. In some embodiments, the layer 102B may be covered or implemented by a coating 608C in addition to or instead of the coating 608 on the film layer 102. Additionally, coating 608C on layer 102B (which can be on any side, but is shown on the top side) can provide electrical connection to features 606C, such as, for example, electrodes or other sensing elements, light sources, or other components, either directly or through intermediate connecting members such as traces or conductive vias.

[0133] In structures incorporating reflectors or other optical features provided by metal coatings, such as LEDs or other illuminators, the coating can be split, for example, along an optical non-occlusion line to separate the power rails and connect to the embedded components through the film. The split line can be hidden by the use of a non-conductive overcoat, such as NCVM (Non-Conductive Vacuum Metallization). This allows for the manufacture of illuminators or other items that have, for example, a conventional appearance, but also control features, such as electronics embedded in the structure. For example, when LEDs or other electronics are embedded inside a structure, the same continuous plating or coating in general that is used as the reflector and / or power distribution line can also be used to dissipate heat, allowing even the entire surface of the part to act as a large heat sink, increasing the LED light output and / or extending the part life.

[0134] Coating 600 may refer to, for example, electroless plating (eg, Cu, Ni), electrolytic plating (eg, Cu, Cr, Au, Ag), or PVD (physical vapor deposition) coatings incorporating, for example, metals and metal-like materials.

[0135] Metallic coatings can provide excellent thermal and electrical conductivity, and furthermore, the coatings can be relatively easily applied to a variety of potentially complex shaped items and layers.

[0136] Considering the general applicability of the different methods, the thickness of the PVD coating can be varied over a fairly wide range, making it possible, for example, to limit diffusion with masking. The stacking of different materials can make it possible to create platings that are suitably conductive and visually attractive, for example by stacking copper and chrome platings.

[0137] In various embodiments, wet processed plating such as electroless copper or nickel with a chrome overcoat may also be utilized, for example in connection with hermetic sealing structures that are resistant to water ingress. Surface features such as connectors may be masked to protect them from exposure to processing solutions. Masking may be performed with photoimageable spray masks, similar to circuit board manufacturing.

[0138] The plating, or coating in general, used for the shield can be made thicker locally to conduct heat away from the embedded electronics, which requires having adequate process control to increase the layer thickness locally to a meaningful extent.

[0139] As mentioned above, in some embodiments, patterning a conductive coating or specifically a plating can be used to create a resonant structure for an embedded antenna to break galvanic contact between the light emitting electronics and the external environment. This can be beneficial in certain highly weather exposed locations, such as turn signal housings or "shark fin" antennas, for example.

[0140] In various embodiments, a metal coating may be provided on a host surface, such as a film layer 102, 102B. The coating area may then be locally shaped to assume a three-dimensional shape, such as a protrusion or recess (e.g., a hemispherical dome or bowl) shape, such that the coating fractures at the location of maximum local material deformation (dome / bowl edge or generally at the shape edge). Thus, the fracture line(s) may define functional, potentially electrical, features such as sensing, field shaping, or shielding functions, in addition to any potential aesthetic or informational (e.g., indicating a sensing area) functions that the coating may have.

[0141] FIG. 7 illustrates at 700 one embodiment of a multi-layer structure according to the present invention having integrated trace shield features.

[0142] The illustrated embodiment includes sensing features 706, such as sensing electrodes, disposed on film layer 102. Although feature 706 is shown on the top side of layer 102, and thus facing layer 104, a similar feature may alternatively or additionally be located on the opposite side. The top side may be referred to as the front side, as it may face the user / environment in some use scenarios, while the opposite side may be referred to as the back side, which may then face a host device, host surface, or host structure.

[0143] However, as will be apparent, the applicability of the proposed shielding solution is not limited to any particular usage scenario or orientation, and thus terms like "front" and "back" should not be considered to limit the viability of the solution only where such terms are similarly relevant. Feature 706 may implement, for example, a capacitive sensing electrode, such as a self-capacitive sensing electrode, or an inductive sensing electrode. Feature 708 refers to further electrical features, such as traces or other conductive features that connect feature 706 to local or external control electronics (not explicitly shown, but already visualized and discussed multiple times herein with reference to other figures) that may drive feature 706 (provide voltage / current) and / or measure its properties, such as changes in capacitance.

[0144] Shielding features 710, for example comprising metal or other conductive material, are provided on film layer 102B by an appropriate method, such as a selected printing or lamination method, on the layer (e.g., on the underside as shown, thus facing layer 104 instead of the environment, and / or on the upper side facing and connecting to the environment, either directly or through further upper layer(s) not shown), or as defined by the material and / or shape of layer 102B itself.

[0145] The shielding feature 710 preferably overlaps the underlying feature 708, essentially obscuring it from at least one selected direction. The feature 710 does not overlap the actual sensing feature 706 to avoid reducing its sensitivity, although in some other embodiments overlap may actually be desired, for example, to adjust the directionality of the sensing feature 706. When an object such as a finger or stylus touches or approaches the structure 700 from the top or "front" direction, it does not induce interference, for example in the form of false or "ghost" detection of the sensing feature 706 through the feature 708, because the feature 708 is shielded by the feature 710.

[0146] Particularly when relatively wide sensor traces are utilized (0.3 mm or greater), e.g., to enhance durability when subjected to stretching during, e.g., thermoforming or other processing, the sensor traces are susceptible to unintended touch detection and coupling to external electromagnetic noise.

[0147] The proposed shielding can improve false touch tolerance, reduce electromagnetic noise coupling to such traces, and facilitate keeping the actual sensing features, such as electrodes 706, relatively small (reducing spatial constraints, allowing for a denser layout of features, etc.).

[0148] The shielding feature 710 may be floating or may be grounded, for example to system / circuit ground (the ground connection may be established by various previously discussed measures of connecting features, not explicitly shown in the figures). In some embodiments, it may be actively driven (e.g., galvanically connected to control electronics for such purposes).

[0149] Feature 710 may be any layer of conductive material, e.g. a) printed conductive hatches (cost optimized fill ratio per target), and / or b) A printed conductive ink layer which may also establish some of the decorative aspects of the structure.

[0150] One additional point to note is that when feature 710 is implemented on the underside of layer 102B as shown, it is still sufficiently far from the (upper) surface of structure 700, e.g., with respect to electrostatic discharge (ESD) shielding.

[0151] Next, selected, yet merely exemplary, implementation options are listed to facilitate the skilled reader's task in determining the optimal option for each particular usage scenario that comes to mind. 1. An illustrated scenario where the traces and electrodes reside on the top of one film layer (e.g., the back film from the user / environment perspective) and the ground connection shield resides on the bottom of another front film layer (above the traces, i.e., between the sensing input area / volume and the traces). 2. Same as above, but with a floating (non-grounded) shield 3. Same as above, but the signal is also sent to the shield (driven shield), which may increase liquid tolerance, for example, if the driven shield surrounds the sensor electrode. 4. An additional overlay 705 disposed over, for example, a sensor electrode on the bottom of a first film layer (e.g., bottom layer 102) and a ground electrode on the top of another film layer (e.g., 102B)+another film layer. The overlay may include or consist of a variety of materials, including, for example, electrically insulating materials. The overlay may, for example, a.Veneer (e.g. wood); b. Fabric, and / or c. may include a molding material resulting from, for example, a second shot surface injection molding or generally a plastic material (layer 104 may be well molded as previously discussed) 5. A two-layer touch surface or typically a sensing pattern on two sides of a film layer (back / lower film layer) protected by a ground shield on the other film layer (top / upper film layer) above the traces 6. A multi-layer touch surface pattern on the underside of the front film layer and on either side of the back film layer. A ground electrode can be provided on the top side of the top / front film and a potential overlay is added on top of the front film. 7. The shielding may be localized or may extend over the entire target surface, for example with opening(s) provided for the sensing area(s).

[0152] 8 provides at 800 a sketch of a test scenario performed to evaluate trace shielding according to an embodiment of the present invention. The multi-layer structure is provided with several embedded sensing features such as electrodes 806 and associated connection traces 808 leading to control electronics that can be provided within the structure or external to the structure via necessary connections. Item 814 refers to a test object, mimicking, for example, a human finger or other stylus, hovering over the structure and / or touching it on the traces 808. Item 810 refers to possible (ground) shielding features, such as hatch shields (hatches), embedded in the structure, for example as discussed above.

[0153] FIG. 9A shows the electric field in the scenario of FIG. 8, where no trace shield features are embedded.

[0154] FIG. 9B shows the electric field when trace shielding is present.

[0155] As can be easily detected from Fig. 9A and Fig. 9B generated by simulation, during testing, the effect of an object 814 placed on the trace 808 was found to be significantly weaker in the sensed signal when it was protected by a shield. As a result, smaller sensor electrodes can be used, providing better sensing feature spatial density, if desired, and also providing lower manufacturing costs. Moreover, with proper shielding, wider traces can be utilized. The traces can be hosted by the same layer as the actual electrodes, which can reduce the use of conductive vias, for example. The shielding can be located relatively far from the sensor traces (e.g., more than twice the trace width), which can reduce undesired capacitive coupling between them. The shielding solution also provides an overall enhanced protection against electromagnetic interference.

[0156] FIG. 10 illustrates at 1000 one embodiment of a multi-layer structure that is provided with multi-faceted or multi-directional sensing capabilities, for example, for touch and / or proximity sensing.

[0157] The need to provide, for example, touch sensors or generally touch or proximity sensing capabilities on both sides of a multi-layer structure supporting simultaneous operation without significant mutual interference may arise with reference to, for example, human-machine interfaces of various devices including vehicles such as land vehicles / cars, aircraft, seaplanes, spacecraft, and their control panels or generally control features or surfaces, in view of, for example, steering wheels and control sticks provided to a user such as a pilot or passenger.

[0158] According to the proposed solution, a further substrate element, such as a film or film layer 102D, defining or hosting at least one, optionally printed, shielding / ground feature 1004, 1008, is disposed between the two operational touch or generally sensing surfaces provided on the film layers 102, 102B. The layer 102D thus integrates a shielding or specifically a ground plane that protects and substantially isolates the upper and lower or orientation sensing features 1002, 1006, 1010, 1012 from mutual interference.

[0159] As shown in the figure, layer 102C or other intermediate layers may house some sensing features 1006. Film layer 102D may include an electrically insulating and / or conductive material, such as a plastic or, in particular, a thermoplastic material. It may be flexible or substantially rigid. In some embodiments, it 102D may be established from the same film as at least one other layer 102, 102B according to the embodiment (102C) of FIG. 2.

[0160] Although not shown in the figures, the outer surfaces of the films 102, 102B may also carry sensing features. Electrical connections such as traces and control circuitry have been omitted for clarity, but considerations provided elsewhere herein regarding such are generally applicable here. The sensing features 1002, 1006, 1010, 1012 may define at least a portion of capacitive sensing, such as self-capacitance or mutual capacitance sensing, or inductive sensing, for example.

[0161] One, still merely exemplary, application area of ​​the above sensing configurations may include a controller device such as a vehicle steering wheel or other user input / user interface device, which may be equipped with a touch sensor or track pad on one side and a similar or different sensing configuration on the opposite side.

[0162] For example, from the user's perspective, the so-called front side facing the user may have a clear meaning for purposes such as menu scrolling, application browsing, and / or their selection. The back side sensor(s), such as a trackpad, may be more versatile, without a predefined fixed operation. Yet, in some embodiments, the back side sensor may be operable (or associated with any target function) only after a selected front side sensor is activated (e.g., a constant input such as a finger press type required to receive back side input).

[0163] FIG. 11 illustrates, at 1100, a flow diagram according to one embodiment of the method of the present invention.

[0164] At the beginning of the method of manufacturing a multi-layer structure, a start-up step 1102 may be performed. During start-up, necessary tasks such as material, component and tool selection, acquisition, calibration, and other configuration tasks may be performed. Special care must be taken to ensure that the individual element and material selections work together and survive the selected manufacturing and installation process, which of course is preferably checked in advance based on manufacturing process specifications and component data sheets, or by, for example, inspecting and testing manufactured prototypes.

[0165] Thus, the equipment used, such as moulding / IMD (in-mold decoration), lamination, gluing, (thermo)forming, casting, electronics assembly, peeling, cutting, drilling and / or printing equipment, among others, can for example be brought up to operational status and tested at this stage.

[0166] In 1104, at least one substrate film, optionally at least partially flexible, is obtained, including, for example, plastic and / or other material(s) as previously discussed, to accommodate a number of features, e.g., electrodes such as sensing electrodes, optionally associated circuitry, sensing response matching features such as one or more additional electrodes, shields, field shapers, etc., and / or other features such as graphics, material layers, optical elements, etc. The substrate film may initially be substantially flat or, for example, curved.

[0167] A prefabricated element, such as a roll or sheet of plastic film, may be obtained for use as a substrate material in some embodiments. In some embodiments, the substrate film itself may first be molded or otherwise manufactured from some selected starting material(s), or may at least be processed, and optionally cut and / or coated. Optionally, the substrate film may be further processed at this stage. Although items 1108-1114 are disclosed separately and in a specific order for clarity, those skilled in the art should easily understand that the mutual order of the items may be flexibly changed, for example, they may be performed alternately and repeatedly, may be integrated, or may be divided into smaller ensembles, depending on each specific usage scenario. Moreover, one or more items may be selectively omitted from the embodiment.

[0168] Thus, item 1108 refers to providing features, such as conductive layers or areas defining, for example, several conductor lines (e.g., traces, defining at least a part of a circuit design), electrodes and / or contact pads, on either or both sides of the substrate film(s), preferably, but not necessarily, by one or more additive techniques, such as printed electronics techniques, deposition, transfer lamination, etching, etc. For example, screen, inkjet, flexographic, gravure, or offset lithographic printing may be utilized. Also, further actions may be taken now or after providing further features, such as, for example, electronic components, to the film(s) to refine the film(s), including, for example, coating or plating in particular, and / or printing, or generally providing decorative or informational graphics, such as visual indicators thereon. Several vias may be provided and filled, for example, with conductive material(s) or generally with feature(s), and / or several conductive features may be disposed through the film(s).

[0169] At 1110, some electronic components such as prefabricated components, e.g. various SMDs, may be attached, e.g. by solder and / or adhesive, to target areas (e.g. conductors / contact areas / pads provided by printing at 1108) on the film(s). Alternatively or additionally, printed electronics and / or other enabling techniques may be applied to actually fabricate at least a part of the components, such as OLEDs, directly on the film(s). Item 1109 indicates that subassemblies, such as system-on-chip assemblies, may be provided on the film(s).

[0170] At 1112, a number of, for example, optical or other types of functional features may be provided on the substrate film(s) by attachment or direct fabrication.

[0171] At 1114, 3D shaping of the substrate film(s) may occur, for example using hot or cold forming. As a result, the substrate film(s) assume a desired three-dimensional (essentially non-planar) shape. Thus, the substrate film(s) containing a suitable formable material are shaped to better fit the target environment / device and / or to better accommodate various features. Alternatively, shaping may occur before providing at least some functional features, such as electronics, on the film(s) if the prefabricated multi-layer stack is designed to survive such processing, or after shaping, for example.

[0172] At 1116, at least one layer of material, as contemplated above, optionally including, for example, a thermoplastic material, is disposed on the substrate film(s), for example, covering one or more (first) functional features already provided thereon. As mentioned above, for example, molding, casting, or further selected lamination techniques are generally applicable here. As discussed above, several materials with different elasticity, dielectric constant, and / or permeability may be provided to affect and tune the sensing properties, for example, sensitivity.

[0173] In practice, one or more of the substrate films or film layers may be used as an insert, for example, in an injection molding process. One side of the substrate film may, at least in some embodiments, remain free of molded plastic. For example, if two films / film layers are used, they are both inserted into their own mold halves and the plastic layer is injected between them. Alternatively, a second and potentially further film may then be attached to the assembly of the first film and plastic layer by a suitable lamination technique.

[0174] As regards the resulting overall thickness of the resulting stacked multi-layer structure, it depends, for example, on the materials used and the associated minimum material thickness that provides the necessary strength in view of the manufacturing and subsequent use. These aspects need to be considered on a case-by-case basis. For example, the overall thickness of the structure can be about 1 mm or a few millimeters, although significantly thicker or thinner embodiments are also feasible.

[0175] In some embodiments, as discussed in connection with the description of FIG. 2, a single film may be folded, or generally bent, to define multiple layers in a multi-layer stack.

[0176] Item 1118 refers to providing one or more additional features, such as various material layers, materials, components, internal connection features (e.g., conductive features between / through the layer(s)) and / or connectors within the structure. Additionally, various post-processing tasks may be performed at this stage. Additional layers may be provided to the multi-layer structure by lamination or, for example, suitable coating (e.g., deposition) procedures. The layers may be of protective, instructional and / or aesthetic value (graphics, colors, shapes, text, numerical data, etc.) and may contain, for example, textile, leather, or rubber materials instead of or in addition to plastics. Additional elements, such as electronics, may be installed on the outer surface(s) of the structure, such as the exterior surface of a substrate. Provided connector or connector cable type features may be connected to desired external connection elements, such as external connectors or connector cables of an external device, system or structure.

[0177] At 1120, method execution ends.

[0178] The scope of the present invention is determined by the appended claims and their equivalents. Those skilled in the art will appreciate that the disclosed embodiments have been constructed primarily for illustrative purposes, and that other configurations applying many of the principles described above can be readily prepared to best suit each potential usage scenario.

Claims

1. 1. An integrated multi-layer structure suitable for use in sensing applications, said multi-layer structure comprising: at least one plastic layer (104) having a first side and a second side opposite the first side; at least one film (102, 102B) layer disposed on both a first side and a second side of the at least one plastic layer; said at least one film layer (102) on said first side of said at least one plastic layer comprises electronics (103, 110, 112, 114, 116, 305, 404, 405, 505, 506, 508, 510, 606, 606B, 608, 706, 708, 1010, 1012) incorporating reactance sensing electronics for the detection of one or more selected target quantities or qualities and their conversion into a representative electrical signal, said sensing electronics comprising at least one electrode and a galvanic connection element for connecting said electrode to an associated control circuit that drives said at least one electrode; the at least one film layer (102B) on the second side of the at least one plastic layer comprises one or more features (105, 118, 120, 124, 126, 128, 306, 408, 512, 606C, 608C, 710, 810, 1002) including at least one conductive feature, the one or more features configured to form an electromagnetic field to adapt a sensitivity or directionality of a sensing response of the sensing electronics on the first side of the at least one plastic layer, the sensing electronics including one or more electronic components disposed on the at least one film layer on the first side of the at least one plastic layer; at least one plastic layer includes a volume of elastic material locally disposed over the at least one electrode of the sensing electronics and / or beneath a predefined sensing area on the at least one film layer on the second side of the at least one plastic layer, the volume being configured to compress in response to an external force exerted through the at least one film layer. Multilayer structure.

2. 10. The multi-layer structure of claim 1, wherein the at least one film layer on the first side of the at least one plastic layer comprises an electrically insulating material having an electrically conductive coating (608) thereon.

3. 3. The multi-layer structure of claim 1 or claim 2, wherein the at least one electrode of the sensing electronics defines at least one f (508, 510), and elements of the electrode pattern are provided in one or more layers on either side of the at least one film layer on the first side of the at least one plastic layer or on opposite sides of the at least one film layer.

4. The multi-layer structure of claim 3 , wherein the electrode pattern comprises a mutual capacitance sensing pattern of multiple transceiver electrodes or a self-capacitance sensing pattern of multiple sensing electrodes.

5. 5. The multilayer structure of claim 1, wherein the at least one film layer on the first side comprises a first film (102) and the at least one film layer on the second side comprises a second film (102B).

6. 6. The multilayer structure of any one of claims 1 to 5, comprising a film (102C), a first section of the film (102C) defining at least a portion of the at least one film layer (102) on the first side of the at least one plastic layer, a second section of the film (102C) defining at least a portion of the at least one film layer (102B) on the second side of the at least one plastic layer, the first and second sections being connected by a third section extending between the first and second sections.

7. 7. The multilayer structure of claim 1, wherein the one or more features include at least one conductive or insulating functional element locally defined by the material of a film of the at least one film layer on the second side of the at least one plastic layer.

8. 8. The multilayer structure of claim 1, wherein the one or more features comprise a conductive material that constitutes at least a portion of a film of the at least one film layer on the second side of the at least one plastic layer.

9. 9. The multilayer structure of claim 1, wherein the one or more features include at least one electrically conductive, thermally conductive or insulating element defined by additional electrically conductive or insulating material provided on a film of the at least one film layer on the second side of the at least one plastic layer.

10. 10. The multilayer structure of claim 9, wherein the element extends locally onto the film.

11. 10. The multilayer structure of claim 9, wherein said elements extend across a major portion or entire surface of at least one side of said film.

12. 12. The multilayer structure of any one of claims 1-11, wherein at least one of the one or more features comprises a colored conductive material on a film of the at least one film layer on the second side of the at least one molded plastic layer.

13. At least one of the one or more features is located adjacent to a predefined sensing area or volume established by at least one electrode and further electrodes or reference patterns provided within the multi-layer structure, or is located at least partially overlying a conductive trace of the sensing electronics, the at least one feature comprising: a. an electromagnetic shield (710) for shielding a sensing area, sensing volume, or said conductive traces from external or internal electromagnetic disturbances or interference; and b. an adjuster (408) of an electromagnetic or electric field for adjusting the sensitivity of said sensing volume.

14. 14. The multi-layer structure of claim 1, wherein the sensing electronics and the one or more features define one or more sensing areas or volumes on either side of the at least one plastic layer, the multi-layer structure further comprising an intermediate film (102D) within the at least one plastic layer, the intermediate film being at least partially made of or provided with a conductive material that defines an electromagnetic shield or ground plane to reduce mutual electromagnetic interference between the sensing features on either side.

15. 15. The multilayer structure of any one of claims 1 to 14, wherein the one or more features define at least one element selected from the group consisting of an electrode or electrode pattern configured to establish a mutual capacitance sensing arrangement with the at least one electrode of the sensing electronics, an electrode or electrode pattern on a side of a film of the at least one film layer on the second side of the at least one plastic layer facing the at least one plastic layer and configured to establish a mutual capacitance sensing arrangement with the at least one electrode of the sensing electronics, a contact or non-contact sensing area, a non-conductive vacuum metallization (NCVM) coating, an electroless plating based coating, a physical vapor deposition (PVD) coating, a capacitively coupled electromagnetic or electric field adjuster, a parasitic coupling based sensing feature, a reference electrode, an actively or passively coupled reference plate, a ground electrode, and a floating ground, earth connection, or circuit ground connected ground electrode.

16. 16. A multilayer structure according to any one of claims 1 to 15, wherein the volume of elastic material comprises a dielectric constant equal to or greater than a threshold value of about 5 and / or a dielectric constant that exceeds the dielectric constant of a primary material of the at least one plastic layer.

17. A multilayer structure according to any one of claims 1 to 16, comprising a galvanic connection element between the sensing electronics and the one or more features.

18. 18. The multilayer structure of any one of claims 1 to 17, comprising at least one protective or decorative overlay layer over the at least one film layer on the second side of the at least one plastic layer, the overlay layer comprising at least one material selected from the group consisting of veneer, wood, textile, fabric, natural biomaterial, molding material, injection molding material, and plastic.

19. A method (1100) for manufacturing an integrated multi-layer structure for sensing applications, comprising: Obtaining a film (1104); configuring the film with reactive sensing electronics (1108, 1110, 1112) for sensing one or more selected target quantities or qualities on a surface of the film and converting the same into a representative electrical signal, the sensing electronics including at least one electrode and a galvanic connection element connecting the at least one electrode to an associated control circuit that drives the at least one electrode, the sensing electronics including one or more electronic components disposed on the at least one film layer on the first side of the at least one plastic layer; configuring the film with one or more features (1108, 1110, 1112) including conductive features on a surface of the film, the one or more features configured to shape an electromagnetic field to tailor a sensitivity or directionality of a sensing response of the sensing electronics; Positioning and configuring (1116) the at least one plastic layer, with respect to the film, the at least one plastic layer defining an integral interface between the sensing electronics and one or more features hosted by the film; positioning and configuring the at least one plastic layer, the at least one plastic layer including a volume of elastic material, locally disposed over the at least one electrode of the sensing electronics and / or beneath a predefined sensing area on the at least one film layer on one side of the at least one plastic layer, the volume configured to compress in response to an external force exerted through the at least one film layer; The method includes:

Images