Multilayer Structures with Embedded Sensing Functionality and Related Fabrication Methods

Abstract

Disclosed is an integrated multi-layer structure suitable for use in sensing applications. The multi-layer structure includes: at least one plastic layer (104); at least one layer of films (102, 102B) disposed on both sides of the plastic layer, the film layer (102) on the first side of the plastic layer including electronic devices (103, 110, 112, 114, 116, 305, 404, 405, 505, 506, 508, 510, 606, 606B, 608, 706, 708, 1010, 1012), the electronic devices incorporating reactance sensing electronic devices for sensing a selected target quantity and converting the quantity into a representative electrical signal. The sensing electronic devices include electrodes and connection elements for connecting the electrodes to control circuitry, and the film layer (102B) on the second side of the plastic layer includes features (105, 118, 120, 124, 126, 128, 306, 408, 512, 606C, 608C, 710, 810, 1002) including one conductive feature, the features being configured to adjust the sensing response of the sensing electronic devices on the first side of the plastic layer.

Description

Technical Field

[0001] The present invention generally relates to electronic devices, associated devices, structures, and manufacturing methods. Specifically, but not exclusively, the present invention relates to manufacturing multi-layer structures incorporating a number of features for sensing or other purposes. Background Art

[0002] In the context of electronic devices and electronic products, there are various different stacked assemblies and structures.

[0003] The motivations behind the integration of electronic devices and related products can be as diverse as the associated usage contexts. When the resulting solution finally exhibits a multi-layer nature, what may initially be sought could be size savings, weight savings, cost savings, or simply an efficient integration of components with associated, potentially synergistic functions. In turn, the associated usage scenarios can involve product packaging or food packaging, the visual design of device enclosures, wearable electronics, personal electronics, displays, detectors or sensors, vehicle interiors and vehicle electronics, antennas, tags, etc.

[0004] Electronic devices such as electronic components, ICs (integrated circuits), and conductors can generally be disposed on a substrate element by a variety of different techniques. For example, off-the-shelf electronic devices such as various surface mount devices (SMDs) can be mounted on the substrate surface that will ultimately form the internal or external interface layer of the multi-layer structure. Additionally, techniques falling under the term "printed electronics" can be applied to actually produce the electronic devices directly and additionally onto the associated substrate. The term "printing" in this context refers to various printing techniques capable of producing electronic devices / electrical components from a print by a substantially additive printing process, including but not limited to screen printing, flexographic printing, lithographic printing, and inkjet printing. The substrate used can be an organic flexible printing material, although this is not always the case.

[0005] The concept of injection molded structural electronics (IMSE) actually involves constructing functional devices and their components in the form of a multi-layer structure that encapsulates electronic functions and possibly other functions.

[0006] In the IMSE process, different features of the desired functions can first be applied to a substrate film. Then, the film can be inserted into an injection molding cavity where a hot melt material is injected onto the film or, in the case of several layers of film, between the films, thereby becoming an integral part of the resulting multi-layer structure.

[0007] An interesting feature of IMSE also lies in that electronic devices are generally (but not always) manufactured in 3D (non-planar) form based on 3D models of the entire target product, component, or general design. To achieve the desired layout of electronic components or other components on the substrate and in the associated final product, a two-dimensional (2D) electronic device assembly method can still be used to place the electronic devices on an initial planar substrate (such as a film), on which the substrate containing the electronic devices can optionally be subsequently formed into a desired three-dimensional (i.e., 3D) shape and overmolded, for example, by covering and embedding a suitable plastic material such as the underlying electronic devices to protect and potentially also hide the components from the environment.

[0008] In some usage scenarios, spatial constraint limitations can restrict the amount and nature of the functions that can be integrated in a multi-layer structure containing an IMSE structure.

[0009] For example, various functional features to be integrated in a common structure may require a relatively large amount of space (such as mounting surfaces) to first accommodate all of one or more associated physical components, and second, to maintain the necessary distances between other features simultaneously to facilitate, for example, reducing mutual induction or external coupling noise, and thus improving the signal-to-noise ratio, enabling accurate, reliable, or otherwise optimal operation in different applications containing sensing solutions and avoiding inaccuracies, unreliabilities, or otherwise sub-optimal operations such as mismeasurements or so-called false positives (false detection of user inputs).

[0010] Since there may be noise features that can cause electromagnetic interference to the environment, and at the same time there may be features that are particularly sensitive to interference during their normal operation, the integration of these two types of features may prove particularly challenging. Obviously, compensating for the noisy environment by increasing the size of the sensitive features will lead to even greater problems related to space consumption. Sometimes, parts of the integrated features such as electronic features should be kept closer to the external environment such as the usage environment of the relevant overall structure, while it would be beneficial to keep some other features closer to, for example, the main device or main structure that houses or connects to the multi-layer structure. Combining such objectives successfully may be laborious (if not impossible), especially in the case of traditional, planar, and rigid electronic designs and limited space with only complex shapes available for integrating these features.

[0011] Sometimes, through certain design choices, such as using low-noise electronics (e.g., linear LED drivers instead of switched drivers), it may be possible to reduce the amplitude of the generated interference 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 multiple features aimed at jointly establishing a functional whole may be further affected by a suboptimal (e.g., too short) distance between them. In some scenarios, several electrical functional conductive features are superimposed, which requires using, for example, a dielectric layer as an intermediate layer. As a result, the number of processing stages may increase significantly, and different unwanted problems such as crosstalk may still occur, and the physical layout design of the structure will ultimately also be subject to a large number of annoying restrictions, which may also have a negative impact on the overall usability of the resulting product. However, when features are tightly packed, their accidental activation and problems caused by thermal management can easily become real problems.

[0012] In some usage scenarios, it may be desirable for the material to deflect to enhance the sensitivity of, for example, a self-capacitive or force-sensing solution, and an air cavity can be included in the structure to achieve this. However, the use of an air cavity may cause various problems, such as material compatibility problems and a tendency for the integrated structural layers to delaminate from each other.

[0013] Furthermore, certain materials such as metallic materials or other highly conductive materials cannot be used as overlays because the materials can effectively prevent the correct operation of the underlying functional features. Correspondingly, the underlying features have already set limitations on the aesthetic and visual characteristics of the structure, and these limitations may create an external surface or otherwise visible potential tactile surface in a large number of end products.

[0014] Still, for example, in different sensing solutions, electric fields, magnetic fields, or generally electromagnetic fields can be generated and measured to detect the quantity and quality of selected targets. However, the controllability of the intensity, size, shape, and alignment of such fields may still be very poor, which also has a negative impact on, for example, spatial sensing resolution and the achieved effective signal-to-noise ratio. Shielding external electrical interference or different physical or chemical phenomena may further prove challenging. Further, due to the limited conductivity of, for example, conductor materials used in additive manufacturing, effective power distribution is troublesome in many scenarios.

[0015] Still further, in some cases, it has been found that including several conductive layers and, for example, current connection layers or general features in a common structure is tricky because the relevant features themselves or the required connection components are difficult to accurately position and align, and the quality of the connections obtained between multiple layers (such as electrical connections) may still be suboptimal to some extent. Summary of the Invention

[0016] The object of the present invention is to at least mitigate one or more of the above-mentioned drawbacks associated with existing solutions in the context of an overall multi-layer structure and functional elements or features such as electronic devices embedded therein.

[0017] The object is achieved by various embodiments of a 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, optionally in touch, proximity or specifically gesture, force, pressure, strain, surface level or flow sensing of substances such as fluids, comprises:

[0019] at least one plastic layer, said at least one plastic layer including, for example, a molded or cast layer, optionally including a substantially electrically insulating material, having a first side and an opposite second side;

[0020] at least one optionally plastic film layer, said at least one film layer being provided on both the first side and the second side of said at least one plastic layer, for example one or two film layers on each side;

[0021] the at least one film layer on the first side of said at least one plastic layer includes an electronic device, which advantageously incorporates reactance sensing electronic devices for sensing one or more selected target quantities or specifically qualities optionally indicative of touch or proximity of an external object relative to the structure, optionally capacitive sensing such as projected capacitive sensing and / or inductive sensing and converting the quantity or quality into a representative electrical signal, the sensing electronic devices for reactance sensing including at least electrodes and preferably current connection elements for connecting the electrodes to an associated control circuitry preferably driving said at least one electrode, and the structure optionally accommodating at least a part of the control circuitry; and

[0022] the at least one film layer on the second side of said at least one plastic layer includes one or more features including at least one (electrically) conductive feature, said one or more features being configured to adjust the sensing response, optionally the sensitivity and / or directivity, of the sensing electronic devices on the first side of said at least one plastic layer.

[0023] In various embodiments, the at least one film layer on the first side of the at least one plastic layer is made of or at least includes an electrically insulating material. The at least one film layer can include, for example, plastics such as thermoplastic films and / or various other films or materials as discussed below. However, the at least one film layer can contain a conductive material. Further, the at least one film layer can contain insulating and / or conductive materials on either or both surfaces of the at least one film layer, for example, in the form of one or more coatings, optionally printed, additively manufactured thereon, or otherwise arranged features, transferred (e.g., tape-based) features, laminated additional films, mounted features, etc.

[0024] In various supplementary or alternative embodiments, the sensing electronic device includes one or more elements fabricated, optionally printed, deposited, coated, and / or mounted on the at least one film layer on the first side of the at least one plastic layer, such as electronic components.

[0025] In various supplementary or alternative embodiments, the at least one electrode of the sensing electronic device defines an electrode pattern, and elements of the electrode pattern are disposed in one or more layers on one or opposite sides of the at least one film layer on the first side of the at least one plastic layer.

[0026] In various related embodiments, the pattern includes a mutual capacitance sensing pattern of a plurality of emitter electrodes and receiver electrodes, or a self-capacitance sensing pattern of a plurality of sensing electrodes and optionally a reference (pattern).

[0027] In various supplementary or alternative embodiments, the at least one film layer includes a first film on the first side of the at least one plastic layer and a second film on the second side of the at least one plastic layer.

[0028] In various supplementary or alternative embodiments, the structure includes a film, a first section of the film defining at least a portion of the at least one film layer on the 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 the second side of the at least one plastic layer, wherein the first section and the second section are connected by a third section extending between the first section and the second section, and the third section optionally houses one or more preferably printed conductors extending between the first section and the second section to electrically connect the first section and the second section.

[0029] In various supplementary or alternative embodiments, the one or more features include at least one conductive or insulating functional element locally defined by the material of at least one film layer on the second side of the at least one molded plastic layer, such as a patterned shape.

[0030] In various supplementary or alternative embodiments, the one or more features include a conductive material that forms at least a portion of the film of at least one film layer on the second side of the at least one plastic layer, wherein the film optionally has a substantially uniform or non-uniform composition.

[0031] In various supplementary or alternative embodiments, the one or more features include at least one conductive and / or thermally conductive or insulating element defined by additional conductive or insulating material disposed, optionally printed or coated, on the film of at least one film layer on the second side of the at least one plastic layer, at least one of the at least one element being optionally defined at least on a side of the film of at least one film layer on the second layer of the at least one molded plastic layer facing the at least one plastic layer or on a side opposite the at least one plastic layer.

[0032] In related embodiments, the element extends locally on the film and defines a pattern thereon, for example. The element may alternatively optionally extend as a coating or plating, such as a metal coating, over a major portion or substantially the entire surface of the film on at least one side of the film.

[0033] In various supplementary or alternative embodiments, for example, one or more of the above features of the structure include a colored conductive material, optionally a colored or dyed paint or ink, the material optionally including silver, salts, noble metals, carbon nanotubes, carbon nanobuds, or conductive polymers on the film of at least one film layer on the second side of the at least one molded plastic layer, the material optionally being configured to define graphic features having decorative and / or informative properties, such as symbols, numbers, letters, pictures, regions, or button shapes, geometric shapes, or text.

[0034] In various supplementary or alternative embodiments, for example, one or more of the above features of the structure include at least one feature positioned adjacent to a predefined sensing region or sensing volume established by at least one electrode and another electrode or a reference (e.g., ground) pattern disposed in the structure and / or positioned at least partially superimposed over conductive traces of the sensing electronic device, the at least one feature defining at least one functional element selected from the group consisting of:

[0035] a. An electromagnetic shielding member, such as an EMI or ESD shielding member, for shielding the sensing area, the sensing volume, or the trace from external or internal electromagnetic disturbances or interferences, wherein the shielding member is optionally floating, grounded, or connected to a circuit ground; and

[0036] b. An electromagnetic or electric field regulator for optionally actively adjusting the sensitivity in an optional direction of the sensing volume by dynamically guiding current or potential to the sensing volume, such as controlled by a control electronic device.

[0037] In various supplementary or alternative embodiments, the sensing electronic device and the one or more features at least partially define one or more sensing areas or volumes on both sides 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 shielding member or a ground layer to reduce mutual electromagnetic interference between the sensing functions on both sides.

[0038] In various supplementary or alternative embodiments, for example, one or more of the above features of the structure 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 electronic device, an electrode or electrode pattern on the side of the 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 electronic device, a touch or non-contact sensing area, an NCVM coating, an electroless plating-based coating, a PVD coating, a capacitively coupled electromagnetic or electric field regulator, a parasitically coupled sensing feature, a reference electrode, an actively or passively coupled reference plate, a ground electrode, and a ground electrode with a floating ground, ground, or circuit ground connection.

[0039] In various supplementary or alternative embodiments, the at least one plastic layer includes a volume of an elastic material optionally having a relative permittivity equal to or exceeding a selected threshold (such as about or more precisely 5) and / or far exceeding the relative permittivity of other (such as major) materials of the at least one plastic layer, the elastic volume being locally disposed on the at least one electrode of the sensing electronic device and / or below a predefined sensing area (and its electrodes, for example) on the at least one film layer on the second side of the at least one plastic layer, the volume preferably being configured to be compressed in response to an external force applied through the at least one film layer.

[0040] In various supplementary or alternative embodiments, the structure includes current connection elements, such as conductive springs, contact studs, or flexible connection members, between the sensing electronic device and the one or more features, which are optionally provided by at least one conductive element extending through the molded plastic layer or located at the edge or periphery of the structure.

[0041] In various supplementary or alternative embodiments, at least one protective and / or decorative cover layer on at least one film layer on the second side of the at least one plastic layer, wherein the cover layer includes at least one material selected from the group consisting of veneer, wood, textile, fabric, bio-natural material, molded material, injection-molded material, and plastic.

[0042] According to an embodiment, a method for manufacturing an integrated multi-layer structure for sensing applications includes:

[0043] Obtaining at least one optionally plastic film;

[0044] Providing the at least one film, optionally the first film of the at least one film, with a reactance sensing electronic device advantageously for sensing one or more selected target quantities and / or qualities and converting the quantity or quality into a representative electrical signal, the sensing electronic device including at least one electrode and a preferably current connection element connecting the at least one electrode to an associated control circuitry preferably driving (controlling) the at least one electrode, optionally further providing the at least one film with at least a part of the control circuitry, such as an integrated control circuit;

[0045] Providing the at least one film, optionally the second film of the at least one film, with one or more features including at least one conductive feature configured to adjust the sensing response, optionally the sensitivity and / or directivity, of the sensing electronic device, wherein the providing optionally includes patterning the at least one film and / or preferably adding materials to the at least one film by printed electronics techniques or plating or other forms of coating; and

[0046] Providing and configuring, relative to the at least one film, optionally by molding or casting, at least one preferably plastic layer including a substantially electrically insulating material such that the at least one plastic layer defines a preferably substantially integrated intermediate layer between the sensing electronic device received by the at least one film and the one or more sensing response adjusting features, wherein at least one of the at least one film is optionally formed to further optionally exhibit a selected three-dimensional shape after setting at least a part of the sensing electronic device or the one or more features in the at least one film.

[0047] As will be appreciated by those skilled in the art, the various considerations regarding embodiments of the multi-layer structure provided herein can be flexibly applied to embodiments of manufacturing methods with necessary modifications, and vice versa. However, those skilled in the art can flexibly combine individual embodiments and related features to propose preferred combinations of the features generally disclosed herein.

[0048] According to embodiments, the utility of the present invention stems from multiple issues.

[0049] Generally, through different embodiments of the present invention, customized functional entities can be designed and produced, which are flexibly adapted to different physical body structures with associated characterization forms, shapes, and materials.

[0050] Since the proposed multi-layer structure can contain several functional layers, each functional layer being provided with selected functional features and preferably having an optimal spacing and optional connections (such as electrical connections therebetween) of the layers / features, various features can be effectively integrated together, for example, on either or both sides of one or more of the included film layers, which in turn can reside on both sides of one or more intermediate layers such as plastic-containing layers or other layers produced by molding, casting, or otherwise, while the operation of each feature can still be subtly optimized according to multiple criteria such as (reduced) mutual or external noise coupling or SNR (signal-to-noise ratio), noise tolerance, detection sensitivity, detection directivity, aesthetics, visual and optical considerations, item size, weight, thermal characteristics, and thermal management, etc.

[0051] In various embodiments, several features that produce different functions or effects can be arranged as overlapped on different layers to optionally produce combined or synergistic effects, such as a sensing function combined with aesthetics, informativeness (e.g., guidance / indication), or other visual or optical effects.

[0052] For example, embodiments using two films or film layers on both sides of a component, device, or other type of multi-layer structure or generally at different positions to accommodate electrical features and other occasionally multi-purpose or combined features can help alleviate many problems associated with single-layer solutions, which include but are not limited in any way to, for example:

[0053] - Switch-mode LEDs, data bus traces, and power circuitry systems or other features considered to be noisy, which can now be placed further away from more sensitive features (such as capacitive sensors) if these are arranged, for example, on different film layers;

[0054] - Noise currents, which cannot be efficiently coupled to another film layer when the ground plane has, for example, a star connection and does not flow directly through. The current loop does not cross the second film;

[0055] - Direct coupling of noise through a micro-conductive material (such as many black inks, often mineral-filled inks), where the noise can actually be eliminated. This allows for a greater variety of materials to be used for different purposes, including, for example, decoration and field shaping;

[0056] - Aesthetic or visual concerns: Multi-layer solutions can use functionalized decorative graphic elements, such as, for example, as capacitive sensors or antenna radiators. Additionally, for example, mutual capacitance sensors can be implemented such that they are not affected by unwanted activation, such as through the back side of the structure or other expected passive sides. For example, TX hatch lines can be provided on a predefined back film, but the solution remains highly sensitive to touches on the front (expected activation) surface or direction, as the desired RX pattern can be provided on one or more corresponding surfaces;

[0057] - General misoperation / mis-detection: A wide variety of shields can be printed or otherwise produced such that they are only open on the desired sensing areas where touch sensitivity is required, which can be used to effectively mask "ghost" activations and mis-detections on sensing circuitry, such as electrodes or traces, on the corresponding side. This shield provided on, for example, the front side or user input side of the structure can also act as a "driven shield", making the system potentially highly immune to mis-activation due to, for example, water, as the system can be grounded to a large extent to avoid coupling through water;

[0058] - Spatial concerns and size constraints: Materials with different electrical or magnetic parameters produced (printed, dispensed, etc.) on one film (such as the front film) can be used for field shaping, so that, for example, closely spaced sensing features (such as the touch-sensitive areas defining touch buttons) can appear further away from the signal perspective, or the resulting structure can absorb fields to, for example, limit the EMI emitted by the structure; and / or

[0059] - Optimal functionality and manufacturing challenges: When the shield can "flow out" from the structure to be shielded, it may be more meaningful or practical to utilize shield features, such as printed features. Protecting both the shield and the traces in a single layer is not as effective as covering them over each other without, for example, having to print a dielectric between the wire layer and the shield, potentially over-grounding the capacitive sensor or other sensors.

[0060] In various sensing scenarios and embodiments, the present invention can provide improved sensitivity by providing features such as electrodes printed or otherwise produced on different overlayers (such as membranes in a stacked structure), the overlayers preferably having a deformable or "soft" material therebetween, optionally associated with a high relative permittivity, to translate a deformation caused by a small external force on the structure (such as caused by a touch) into a larger effect on the sensed mutual capacitance or generally the sensed quantity. The use of often problematic gaseous cavities or specifically inflated cavities to achieve sufficient material deformation can be avoided or reduced.

[0061] In various embodiments, the reactive sensing techniques such as capacitive sensing proposed herein can actually be provided by a multi-layer structure, even if the multi-layer structure typically contains highly conductive surfaces (such as metal surfaces), while further eliminating the need for internal gases or specifically inflated cavities that may cause undesired delamination of the structure. Effectively, a touch-through-metal type solution can be provided, for example. However, considering manufacturing, the multi-layer structure according to various embodiments of the present invention can be substantially uniformly established by a single manufacturing process rather than a complex combination of various mandatory methods and post-processing steps. Further, if some material such as aluminum is applied in a thin layer, the material is prone to permanent deformation - in the material stack of the present invention, the stack can thus be configured to act as a "spring" to prevent permanent deformation and thus prevent loss of desired performance aspects. Generally, the multiple layers of the multi-layer structure can be manufactured using various lamination (thermal, pressure, adhesive, chemical, physical, etc.), molding (e.g., multiple times), and / or printing (e.g., printed electronics printing methods) techniques.

[0062] In various embodiments, current unconnected elements provided on one layer can be configured to shape the electromagnetic field to facilitate improvements in operations such as sensitivity and directivity and reduction of noise sensitivity established by an electronic device (such as a sensing electronic device remotely provided on another layer). A similar configuration can alternatively be applied to provide a capacitive feed antenna to provide enhanced efficiency and, for example, facilitate impedance matching between the feed element and the radiating element.

[0063] In various embodiments, the touch or gesture (non-contact) sensing functionality may be provided by the proposed structure or specifically, for example, a panel, by implementing multiple superimposed features therein such as electrode patterns or generally multi-layer or multi-surface electrical arrangements. For example, the patterns may be disposed 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 substantially separate or synergistic effects. For example, considering, for example, illumination or visualization of a sensing area, a multi-touch sensing arrangement may be superimposed with an illumination solution such as many LEDs and / or light guiding structures (such as graphics or other optical forms). One film or layer may implement at least one function (for example, using both sides / surfaces of the layer for this purpose), while another film or layer may be used for another potential synergistic purpose.

[0064] The flexibility and overall coverage characteristics provided by the multi-surface (group) solution may be further translated into a reduction in the use of support features such as dielectric layers, which may still suffer from drawbacks such as crosstalk challenges from the perspective of optimal electrical design and / or require, for example, non-conductive ink traces to overlap in undesirable locations. Omitting unnecessary features from the overall structure or specifically layers such as dielectric layers is advantageous in terms of general simplicity but also considering electrical sensitivity, performance, and cost for layout design. On the other hand, when beneficial, multi-layer and multi-surface designs also enable more efficient system-level or application-level integration, which may be achieved in practice, for example, by the mutually compact positioning of features such as electronic features. For example, system electronic devices such as controllers or integrated circuits may be positioned closer to the sensing area.

[0065] In various embodiments, the multi-layer structure may incorporate a number of functional coatings provided in accordance with the present invention (located on the exterior of the structure and / or embedded on certain internal surfaces / interfaces). In addition to or instead of sensing, such coatings have been found to be useful in various usage contexts such as different lighting applications. The functions may further include, for example, thermal management (the coating may include materials having a selected thermal conductivity for effectively cooling the structure or the contained features or, for example, a sufficiently high thermal insulation capacity), power distribution (for example, a sufficiently high conductivity), electrical shielding (for example, conductivity or insulation capacity), and / or light management (for example, optical transmittance, reflectance at relevant wavelengths such as visible light). However, the coatings may still have decorative / aesthetic and / or informative visual functions.

[0066] In various embodiments, in addition to being applied to provide functional materials such as optical or electrical transmittance or conductivity, printable materials or generally colored or pigmented inks or coatings can also be applied to provide aesthetic, informative, or other visual characteristics such as symbol shapes or geometric shapes. For this purpose, for example, conductive inks or coatings can be colored according to desired color preferences. Thus, underlying non-visual features can be masked from the user without the need to provide additional masking features or position the underlying features out of sight. Reducing the number of layers can then advantageously make the target multi-layer structure simpler, which can facilitate and speed up the manufacture of the layers.

[0067] As already mentioned above, in various embodiments, the present invention can be used to provide effective trace shielding for sensing (such as capacitive sensing) and for other purposes. The shielding or specifically, for example, the grounding element can be provided (among other possibilities) from a conductive material layer using (printed) conductive vias (cost-optimized fill rate per target) or (printed) conductive ink layers, which can also have decorative or other visual functions in a multi-layer structure. Thus, since noise problems and unwanted coupling that cause ghost detection can be reduced, the size of the actual sensing features can be kept moderate, for example, which saves space for other uses or simply to keep the structure compact.

[0068] In various embodiments, several layers of a structure can be established by a single element (such as a folded or generally curved film) to form such layers while optionally remaining integral, which facilitates and also enables providing desired connectivity between the layers, such as conductivity, optical conductivity, and / or thermal conductivity, through connectivity features such as conductor traces provided on the film and extending from one layer to another.

[0069] In various embodiments, a multi-layer structure having multiple simultaneously operable touch-sensitive sides or generally sensing surfaces, layers, regions, or directions can be arranged such that interference between associated sensing functions is reduced and remains small. This can be achieved by shielding or specifically grounding features (such as electrodes) positioned between the sensing functions, and optionally by printed electronics provided on an intermediate substrate layer.

[0070] Generally, different embodiments of the manufacturing methods contemplated herein, although having uniqueness and benefits over the prior art, are still somewhat simple for understanding and use and do not require the use of, for example, complex trial-stage manufacturing techniques to provide selected desired features for sensing or other purposes in a multi-layer structure.

[0071] For example, after forming features such as conductors or other electronic devices on one or more membranes while the one or more substrate membranes remain substantially planar at least in some places, forming the one or more membranes into a desired 3D shape can additionally reduce or eliminate the need for potentially tedious and error-prone 3D assemblies of electronic devices on the substrate membranes or other layers.

[0072] The resulting multi-layer structure can be used to establish desired devices or modules in different body elements, body structures, body devices, or body entities such as: for example, vehicles or specifically (in-vehicle) 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, dashboard, center console, floor, walls, roof) or exterior panels, smart clothing (e.g., shirts, jackets or pants, or e.g., compression clothing), other wearable electronics (e.g., wristband devices, headgear or footwear), personal communication devices (e.g., smartphones, phablets or tablets), and other electronic devices or items or systems containing electronic devices. The integration level of the resulting structure can be high and desired dimensions such as its thickness can be small.

[0073] The one or more membranes and general material layers used can contain graphics and other visually and / or tactilely detectable features thereon. In addition to housing and protecting electronic devices for sensing and / or other purposes, the membranes / layers can have aesthetic (decorative) and / or informational functions on such features. The one or more membranes / layers can be translucent or opaque at least in some places. The one or more membranes / layers can exhibit a desired color or include portions that exhibit a desired color for corresponding parts of the structure. Thus, the resulting multi-layer structure can incorporate one or more colored / colored layers that optionally define graphics such as text, pictures, symbols, patterns, etc. For example, these layers can be implemented by dedicated membranes of a certain or certain colors or provided as coatings (e.g., by printing) on one or more existing membranes, one or more molded layers, and / or other surfaces. One or more outer membranes of the multi-layer structure can be configured to form at least a part of the outer surface and / or inner surface of an associated body product or body structure.

[0074] Various visible or visual features, such as graphic patterns, indicators, or colors, can be provided below the outer surface of the structure such that the features remain isolated and thus protected from the environment by at least the thickness of the body substrate film and optionally the thickness of, for example, a molding or casting layer (depending on on which side of the film and on which film the relevant feature is provided relative to a particular environmental threat). Thus, different impacts, frictions, chemicals, etc. that might readily damage surface features applied, for example, by spraying, printing, mounting, or otherwise, do not affect or reach the features. Material layers, such as those defined by a substrate or other film, can be readily fabricated or processed and optionally cut into desired shapes with necessary characteristics, such as holes or notches, to selectively expose underlying features, such as molded material.

[0075] The expression "a number of" can herein refer to any positive integer starting from one (1).

[0076] The expression "a plurality of" can correspondingly refer to any positive integer starting from two (2).

[0077] If not otherwise explicitly stated or clear to a person skilled in the art, the terms "first" and "second" are used herein to distinguish one element from another and do not specifically determine a precedence or rank them.

[0078] When referring herein to "different" or "respective" embodiments of a multi-layer structure, related manufacturing methods, or features included therein, the embodiments are considered to be complementary to each other and can thus also be implemented in a common embodiment, unless otherwise explicitly stated or clearly known to a person skilled in the art in some other way that the relevant solutions are mutually exclusive and alternative solutions for the same features of the overall solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Next, the present invention will be described in more detail with reference to the drawings, in which:

[0080] Figure 1 An embodiment of a multi-layer structure according to the present invention is shown.

[0081] Figure 2 Another complementary or alternative illustrative embodiment of the present invention is shown, in which several layers of the multi-layer structure are established by a single film.

[0082] Figure 3 An embodiment of a multi-layer structure for supporting force sensing according to the present invention is shown.

[0083] Figure 4 An embodiment of a multi-layer structure according to the present invention is shown, relating to field shaping by using active / feeding elements and shaping elements associated with functions not electrically connected thereto.

[0084] Figure 5 Shows an embodiment of a multi-layer structure for, for example, multi-touch sensing according to the present invention.

[0085] Figure 6 Shows an embodiment of a multi-layer structure having one or more integral functional coatings according to the present invention.

[0086] Figure 7 Shows an embodiment of a multi-layer having shielding features, such as trace shields, integrated therewith according to the present invention.

[0087] Figure 8 Shows a test scenario for trace shielding according to the present invention.

[0088] Figure 9A Shows the electric field measured in a scenario without implementing trace shielding features, such as in Figure 8 the scenario of.

[0089] Figure 9B Shows the electric field in the presence of trace shielding.

[0090] Figure 10 Shows an embodiment provided with a multi-surface or multi-direction sensing function.

[0091] Figure 11 Shows a flowchart of an embodiment of a method according to the present invention. Detailed Description

[0092] Figure 1 Embodiment 100 of a multi-layer structure according to the present invention is shown by a (cross-sectional) side view. The multi-layer structure 100 can form the final product itself, such as an electronic device, or can be placed, for example, as an assembly part or module in a body such as a main device, a main system, or a main structure, or at least connected to a body such as a main device, a main system, or a main structure. The multi-layer structure 100 can include many additional elements or layers, which are not explicitly shown in the figure for clarity.

[0093] The solution shown includes at least two film layers 102, 102B of at least one material such as a plastic resin, etc., optionally, for example, injection molded or cast, and disposed therebetween, and at least one intermediate material layer 104. The two film layers 102, 102B can be physically connected and, for example, electrically connected, thermally connected, and / or optically connected by the at least one layer 104 by, for example, a number of connecting members 108, such as springs (for example, fairly rigid wires), contact studs, optical guides, or similar structures that bridge the gap between the films, or specifically, selected features thereof or thereon, such as conductive / contact pads, traces, and / or electronic components, and / or (by flexible interconnects, springs, pins, or similar means) located at the edges, so as to achieve the necessary connections. However, it is clear that the film layers or features thereof or thereon need not be physically connected in all embodiments, and the film layers or features can still be functionally coupled to each other or affect each other's functions.

[0094] In various embodiments, the film layers 102, 102B (note that there can also be additional film layers in the structure) can include the same or different materials from each other. Similarly, their overall configurations 102, 102B can be similar or different from each other.

[0095] In various embodiments, the film layers 102, 102B can generally include or be composed of one or more materials, such as plastics, for example, thermoplastic polymers and / or organic or biological materials such as wood, paper, cardboard, leather, or fabric, or any combination of these materials with each other or with plastics or polymers or metals.

[0096] Any one of the layers 102, 102B can be visible to the environment of the structure 100, and the layer can even define the exterior of the structure 100, on which the layer can have an aesthetic / decorative or other visual function, and possibly a tactile function (for example, providing a desired feel with a selected surface roughness). Any one of the layers 102, 102B can define or contain apertures such as recesses or vias for accommodating features such as components or, for example, conductive vias.

[0097] For example, any one of layers 102, 102B can generally include or consist essentially of a thermoplastic material. Any of layers 102, 102B can contain a composite material. Any of layers 102, 102B can include a coating on either side thereof. At least in some places, any of layers 102, 102B can be substantially flexible or bendable. In some embodiments, the film layers 102, 102B can be at least partially substantially rigid and hard. The thickness of each of layers 102, 102B can vary according to the embodiment; for example, each layer may be only a fraction or a few percent of a millimeter, or quite thick, such as on the order of one millimeter or several millimeters. Any of layers 102, 102B can have a constant or varying thickness and / or general configuration.

[0098] Based on the foregoing, each or any one of layers 102, 102B can include, for example, at least one material or a plurality of materials selected from the group consisting of: polymers, thermoplastic materials, electrical 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, biological materials, leather, wood, cellulose, textiles, fabrics, metals, organic natural materials, solid wood, veneer, plywood, bark, bark crepe, birch bark, cork, natural leather, natural textile or fabric materials, natural growth materials, cotton, wool, linen, silk, and any combination of the foregoing.

[0099] For example, in some embodiments, the film layer 102B can be substantially homogeneous (e.g., a selected electrical insulating or conductive material, such as a metal sheet), and the film layer can still, for example, accommodate many additional features thereon, such as aesthetic / visual or general optical features, thermal features, chemical features, and / or electrical features. Alternatively, the film layer 102B can be non-homogeneous in terms of at least one selected property, such as conductivity or conductive material. Thus, different portions of layer 102B can define selected functional features or other features, such as electrodes or other sensing elements, electromagnetic shields, field shaping features or other features for adjusting the response of, for example, capacitive or inductive sensing electronic devices disposed on layer 102.

[0100] The foregoing at least one intermediate layer 104 refers to at least one material layer, which is first disposed, for example, on the film layers 102, 102B or directly between the layer 102 and the layer 102B by, for example, molding (such as injection molding) or casting (such as impregnation) of one or more associated materials. Alternatively or additionally, the layer 104 may have been arranged on the film layers 102, 102B by laminating it to, for example, a ready-made component thereon by using, for example, mechanical bonding, chemical bonding, electrical bonding, electrojoining, heat, pressure, solvent, and / or an adhesive.

[0101] The at least one layer 104 may generally include many materials, such as polymers, organic materials, biological materials, composite materials, and any combination thereof. The materials may include one or more thermoplastic and / or thermosetting materials. The thickness of the one or more included layers and other features and thus the overall thickness of the structure 100 may vary according to the embodiment. For example, the variation may be on the order of about one millimeter, several millimeters, or dozens of millimeters. At least some of the materials in the at least one layer 104 may be, for example, electrically insulating or conductive. In some embodiments, the layer 104 may, for example, include at least one material selected from the group consisting of: an elastomeric resin, a thermosetting material, a thermoplastic material, PC, PMMA, ABS, PET, copolyester, copolyester resin, nylon (PA, polyamide), PP (polypropylene), TPU (thermoplastic polyurethane), polystyrene (GPPS), TPSiV (silicone-based thermoplastic vulcanizate), and MS resin. The layer 104 may be of a substantially homogeneous or heterogeneous structure.

[0102] At least locally, there may be many additional layers (for example, coatings, additional film layers, printed conductive layers defining, for example, circuit designs / traces or patterns) or features generally defined or disposed in and / or on the film layers 102, 102B, at least one intermediate layer 104 (on any side or both sides, and / or embedded) and / or elsewhere in the structure. Even if only a single feature is shown as, for example, a rectangular block or a substantially square block at a particular location in the figure for clarity, those skilled in the art should recognize the fact that the single feature may refer to or include a plurality of different and / or similar features to each other, such as a circuit having traces, components, and / or other elements, which may optionally be, for example, electrically connected together (such as by current or capacitance) or otherwise, for example, optically connected together or at least generally functionally connected together.

[0103] Still according to a particular embodiment, these, which potentially include additional layers and / or other features 103, 105, 110, 112, 114, 116, 118, 120, 124, 126, may indeed have been assigned various functions, such as protective, aesthetic, decorative, informative, 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, attachment or fixing functions, and / or spacing functions, etc.

[0104] Features such as more spatially extensive layers 103, 126 (such as printed layers, coated layers, deposited layers, molded layers, or otherwise laminated layers), etc., or more local elements 105, 110, 112, 114, 116, 118, 120, 124 can each have dimensions such as their own thickness (as shown in the figure) and characterizing materials. Alternatively, multiple features such as layers 103, 103B, 103C, etc., can have at least partially the same or similar configurations to each other, for example, in terms of thickness or material.

[0105] Thus, the foregoing features can include, for example, at least one element selected from the group consisting of: electrical conductors such as traces, printed electrical conductors, electrical insulators, electrical conductors, circuit designs, contact pads, circuit traces, electrodes, electromagnetic shields, shadow masks, EMI (electromagnetic interference) shields, RFI (radio frequency interference) shields, electric field or electromagnetic field shapers or attenuators, graphics, graphic ink layers, conductive ink layers, visual indicators, electrical components, electronic assemblies, integrated circuits, optical elements, light-emitting elements, LEDs (light-emitting diodes), OLEDs (organic LEDs), light-detecting elements, lenses, light-guiding 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.

[0106] 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, alloy, silver alloy, zinc, brass, titanium, solder, and any of its components. The conductive material used may be optically opaque, translucent, and / or transparent at a desired wavelength such as visible light, for example, to mask radiation such as visible light or to reflect, absorb, or transmit the radiation therethrough. In some embodiments, the conductive features or insulating features defined by, defined in, or on any layer or feature of a multi-layer construction or other features may have additional functions such as aesthetic, informative, visual, or general optical functions, such as a masking function.

[0107] One or more of the features may have been produced directly, for example, using printed electronics device techniques such as screen printing, flexography, gravure printing, offset lithography, or inkjet printing, onto the multi-layer structure 100 or a specific component of a composition, such as its film layers 102, 102B. Alternatively or additionally, for example, applicable coating methods such as etching or silver plating or flow coating may have been utilized. As a further option, adhesives, heat, and / or pressure may have been used, optionally in the form of a selected lamination method, to attach off-the-shelf features to the structure. As yet a further option, one or more features such as conductive traces, components, heat conductors, and / or other elements may have been provided on at least partially pre-prepared carriers such as tapes (e.g., adhesive tapes or specifically adhesive transfer tapes), which are then arranged onto the film layers 102, 102B or generally onto the structure 100.

[0108] In various embodiments, considering, for example, a predefined wavelength in the visible spectrum, one or more of the included layers and / or additional, for example, more localized features may be at least partially optically substantially opaque or at least translucent. These items may have been further provided with visually distinguishable, decorative / aesthetic, and / or informative features, such as graphic patterns and / or colors thereon or therein. Generally, IML (in-mold labeling) / IMD (in-mold decoration) techniques are applicable for manufacturing such items. The items may be at least partially, i.e., at least in some places, optically substantially transparent to radiation (such as visible light emitted by other electronic devices within or on the structure, for example). For example, the transmittance may be about 75%, 80%, 85%, 90%, 95%, or higher.

[0109] In various embodiments of the structure 100, the included features may include electronic devices, such as control and / or specifically sensing or measuring electronic devices that have been provided on at least one layer of the structure 100, such as the film layer 102.

[0110] For example, items 103, 105 on layers 102, 102B may each include a circuit design that at least includes conductive traces (alternatively or additionally, similar features may also be on the opposite sides of layers 102, 102B, but are omitted in the figure for clarity). Item 114 may include an electronic component, such as an integrated control circuit or other control / measurement electronic device, and item 116 may include a sensing element, such as an electrode, which will be discussed in more detail below. Items 110, 112, 120 may represent, for example, additional components, sensing elements, or connection features, such as connectors to an external system or, for example, a host device. Item 118 may contain, for example, shielding features and item 126 for placement on top of a protective, decorative, graphic-containing, masking, or optically semi-transparent / transparent, informative, or otherwise meaningful and functional layer.

[0111] In some embodiments, from the perspective of a user or usage environment (e.g., a target sensing volume or area) that interfaces with or is at least closer to layer 102B, layer 102 may represent or at least be located closer to the intended back side of structure 100, where the back side may thus optionally be closer to a host device or structure, such as a host device, surface, or panel in a vehicle (e.g., an in-vehicle panel on a dashboard, a door, a center console, etc.) or some other host structure and potentially even attached to or otherwise integrated with the host device or structure or some other host structure. However, in other embodiments, the situation may be reversed (i.e., layer 102B may reside closer to the user / usage environment), or structure 100 may face the user or usage environment from multiple directions.

[0112] The aforementioned included electronic devices may actually contain, for example, one or more control circuits or control circuitry for sensing purposes and / or other uses. At a minimum, the included electronic devices preferably contain, for example, a number of sensors or sensing features in the form of a number of electrodes, which in turn may be driven and / or measured by a control circuitry (e.g., a circuit, such as an integrated circuit and / or a circuit containing discrete, connected components) via a current or wireless connection, where the control circuitry may reside within structure 100, such as disposed on membrane 102, or outside of structure 100 and connected to structure via connection elements such as (electrical) connectors and / or wiring. The sensing features may be wireless in nature, such as capacitive or inductive.

[0113] Sensing features, such as electrodes, can be controlled to establish, for example, an electric field, a magnetic field, or a general electromagnetic field in the environment of structure 100.

[0114] In various embodiments, any of the features such as feature 116 of the film layer 102 or features on the film layer may include or define an electrode or other sensing element for self - capacitance sensing. The element may be configured (material, size / location / distance, etc.) to define a selected parasitic (electrostatic) capacitance to a reference potential such as system or circuit ground, which selected parasitic (electrostatic) capacitance may be changed (increased) by touching or hovering around the multi - layer structure 100 with an object such as a user's finger, and is detected or measured by associated control electronics, for example, by measuring the time constant of an RC circuit including the electrode. Thus, the element may define, for example, a user - input feature, such as a capacitive or specifically a parasitic touch / gesture input area or volume, or a "button". For the user, it may be possible to use, for example, forming relevant surface areas in a structure (e.g., a recess or a protrusion, such as a dome or a bowl shape) and / or a graphical or optical indicator (e.g., illumination) to indicate the element or the associated sensing area / volume.

[0115] In various supplementary or alternative embodiments, for example, a plurality of features such as features 116, 124, etc. on different sides of layer 104 may preferably define electrodes for mutual - capacitance sensing. Here, the control electronics are configured to measure a change (such as a decrease due to an object) in the mutual capacitance between at least two electrodes, i.e., a first electrode and a second electrode, where at least one of the electrodes is a driven / emitting electrode and at least another electrode is a sensing / receiving electrode. Thus, feature 116 may define a first electrode on the first side of layer 104, while, for example, feature 124 may define a second electrode on the second opposite side of structure 100, and both electrodes are connected to a circuit of the measurement / control electronics.

[0116] In various embodiments, at least one feature such as feature 118 may define a shield for shielding underlying electronics such as sensing electronics, associated circuits, or specifically circuit traces from external electromagnetic fields or interference, for example, an electromagnetic shield, such as a floating electromagnetic shield, an active (driven) shield, or a (system / circuit) grounded or earthed shield. For example, the shield 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 that is optionally current - connected to system / circuit ground.

[0117] In various embodiments, at least one feature (e.g., item 128) may define a field regulator that is configured to change, for example, the surrounding electromagnetic field (near - field) established by sensing electronics. The regulator may be dynamically controlled (active / driven) by the electronics or may be passive. The regulator may be connected to an associated system ground or may be floating.

[0118] Thus, considering the aforementioned field regulation type features and shielding features such as of layer 102B and electronic devices substantially located in / on layer 102, according to an embodiment, layers 102, 102B may or may not be electrically connected, for example, such that various features connect current to the same circuit. Such a connection may not be necessary in cases where, for example, the effective permittivity or, for example, the magnetic permeability of the material of the regulator or shielding feature is used to shape the field around a capacitive sensing element or antenna radiator, but the connection enables, for example, dynamic control.

[0119] In various embodiments, functionalized graphics can be utilized, i.e., conductive materials such as inks or coatings can be added to structure 100 for both decorative / aesthetic / informative and electrical purposes, including, for example, forming 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 nanotubes, carbon nanobuds, and conductive polymer inks can be well functionalized in this regard. The conductive ink can be supplemented with desired colored inks. Desired colors can generally be achieved by using suitable dyes or pigments in the material.

[0120] The conductivity of many (if not most) conductive inks, for example, is higher than what is sufficient to act as a touch sensing electrode. Most conductive inks can also be at least slightly colored. The achievable effects depend on the distribution and appearance of the conductive material and the extent to which the material can be diluted while maintaining an acceptable conductivity. "Diluting" the conductive ink with a colored ink can open up a whole new range of interesting and attractive patterns and textures that serve both decorative and functional purposes. For example, coloring the conductive ink can dilute the relatively expensive materials used for large area shields, regulators, sensors, and radiator / antenna printing, thereby reducing production costs.

[0121] For example, when using functionalized graphic inks or similar substances, shields, capacitive touch or other sensing electrodes, antennas, antenna resonators, etc. can be hidden, masked, or camouflaged from external observers while still being positioned close to the outer surface. Even complex sensor patterns can be "hidden in plain sight", thus providing visually interesting features for the designer. Thus, at least for those who do not know exactly what to look for, the implemented functions may actually become invisible.

[0122] Referring to printed outlines or other indicia that indicate the location of a sensing region or general sensing features, for example, or to underlying light sources configured to illuminate the sensing region dynamically (turned on when sensing input is awaited / sensing function is active, or blinking, for example), layers and other features can be masked from both sides while appearing to have a uniform color, where only visual cues required for user interaction are visible, or activation may only be possible when the user approaches the surface.

[0123] As a related example, touchpad or other touch area sensing electrodes can be printed on a surface such as layer 102B in a desired shape, such as a geometric shape or a pattern like a spreading vine. In various usage scenarios, it may be beneficial in terms of sensing performance (sensitivity, directivity, etc.) to have the sensor pattern so close to the external or general target sensing surface.

[0124] As a further example, a selected conductive ink or coating (e.g., black ink) can be configured to establish visually distinguishable features, such as graphic patterns, while the conductive ink or coating can be further used to shield underlying sensing electronics, such as traces, from ghost touches, i.e., false detections, and / or for shaping the electromagnetic field around, for example, touch buttons or other sensing features. The black ink can be patterned such that the resulting isolation patch forms a parasitic resonator - type antenna element (former) to affect the field established or sensed by the underlying electrodes.

[0125] Thus, when using conductive ink, antenna resonators or other functional features can generally be hidden in detectable geometric or other visible patterns on, for example, film layers 102, 102B.

[0126] In various embodiments, electrical connections to a colored conductive ink pattern or similar feature can be arranged through connection features or contact points such as openings in adjacent layers, the adjacent layers being, for example, intermediate layer 104 for contact features such as wires or main film layers 102, 102B. The contact points may be hidden in the pattern.

[0127] One viable option is to add a strong - colored ink to the conductor ink with a similar chemical and solvent. Some conductive inks are derivatives of heavily filled (usually black or white) graphic ink formulations, while others are highly customized and more difficult to add color to. For these cases, it may be appropriate to add dry pigments with an ink - specific solvent to restore flow characteristics.

[0128] Considering that, for example, setting a colored conductive material such as ink on a target surface such as membranes 102, 102B, etc. may not be essentially different from setting or specifically printing any ink, but can optimize, for example, the screen characteristics in the context of screen printing by conducting tests when desired or needed. Since colored conductive inks can be well used in applications where, for example, conductivity is not of utmost criticality, the print quality can be optimized correspondingly for visual quality with respect to the conductive characteristics.

[0129] Even though the multi-layer structure 100 has been shown as a rectangular stack, the multi-layer structure can generally or locally define various shapes because, for example, the membrane layers 102, 102B can be formed using, for example, thermoforming or cold forming to exhibit a desired 3D shape (after or before setting features such as electronic devices thereon), and then additional layers such as the intermediate layer 104 can be set.

[0130] As will be readily understood by those skilled in the art, in any of the more specific or dedicated embodiments described below, various characteristics and features of the above-described more general or potentially multi-purpose multi-layer stack 100 can be freely and selectively adopted, and vice versa. However, the following description of the respective embodiments has been generated to set forth specific, selected aspects in the context of the present invention, and thus the associated disclosure may still lack features that are non-essential from the perspective of understanding the specific aspects. However, as will also be readily understood by those skilled in the art, such features are still fully possible and, in many cases, are advantageously included in the associated disclosed multi-layer structures (for example, if an electronic device is included in the multi-layer structure, it is likely to be advantageous to provide an external electrical connection, a "system connection", etc. to the electronic device using suitable connection members such as connectors, wires, internal connection features, etc.). However, those skilled in the art can selectively combine the features and characteristics of the following embodiments with each other to propose additional embodiments, where the functions of the features below are preferably provided by a common multi-layer structure.

[0131] For clarity, Figure 2 A simplified multi-layer structure 200 is shown that is Figure 1 derived from the multi-layer structure, but those skilled in the art should recognize the fact that structures 100 and 200 can be very similar or quite different from each other in terms of the layers and other features included, the materials used, the dimensions, etc. However, there is at least one difference caused by the construction of the membrane layers 102 and 102B.

[0132] As already mentioned above, in some embodiments, the common substrate film 102C can be folded or bent, as also shown by the dashed lines at the periphery in the figures, so as to define several layers 102, 102B in a multi-layer stack (layer 102B can be considered to be formed by the extension of substrate 102A, or vice versa), rather than using separate films for layers 102, 102B. For example, the connecting middle portion can be retained in the structure or at least partially processed and / or subsequently removed by cutting.

[0133] The connecting middle portion can contain conductive features such as traces or optionally set conductive features such as traces by printing to electrically connect the film layers 102, 102B and their electrical features such as traces, circuit designs, sensing elements and components, etc. together. Eventually, multiple film layers established by at least the initial common film can be provided on the same and / or different sides of layer 104 in the multi-layer stack 200. As shown at 108( Figure 1 )), layers 102, 102B can be optionally further connected together by, for example, conductive vias passing through an intermediate layer (such as layer 104) and / or using one or more other connecting features and preferably conductive features.

[0134] With the solution shown, potential flushing and connection problems due to the use of discrete connecting components (such as springs and pins connecting layers 102, 102B) can be practically eliminated.

[0135] Features such as electrical features (traces, electrodes, etc.) or even electronic components can first optionally be set on any side of the film 102C by printed electronics techniques, and then the film can optionally be formed (such as thermoformed) to exhibit a desired three-dimensional shape, which is, for example, cut and / or bent before at least one layer 104 is disposed therebetween by molding or casting.

[0136] In some embodiments, compared with, for example, layers 102, 102B or the general structure 100, 200, the middle portion can be shaped (e.g., cut) to a reduced width to accommodate, for example, printed conductors but reduce the amount of unused space.

[0137] In some embodiments, an even more general bending can be performed on the film 102C to thereby establish, for example, three layers in structure 200 (an 'S'-type bend having a top layer, an intermediate layer, and a bottom layer).

[0138] Figure 3 An embodiment 300 of a multi-layer structure with improved sensitivity for force sensing and, for example, supporting touch sensing according to the present invention is shown.

[0139] As background information per se, it can be mentioned that for many self - capacitance sensing solutions, for example, it is typical that a relatively high deflection of the covering material is necessary to generate a sufficient pressure effect in terms of the sensing function. This challenge can be solved by including air cavities that promote structural deformation inside the multi - layer stack as mentioned above. However, the inflated cavities may increase the delamination sensitivity of the stack structure layers. Still as another potential challenge, although it may be preferred due to appearance, feel or durability, for example, using a metal covering or generally a top / upper layer may actually completely prevent the operation of the underlying self - capacitance sensing solution.

[0140] Thus, in the illustrated embodiment, a desired level of material deflection that is beneficial for enhancing sensing sensitivity in response to an external force F directed to the sensing location of the structure 300 can be obtained by the volume of at least one more elastic or "softer" material 304, which is disposed below (indicated by the dashed line) the dedicated sensing location or sensing region 310, between or embedded in another less elastic material surrounding the intermediate layer 104 between the film layers 102 and 102B, such that in response to the external force applied to the structure 300 being directed internally towards the structure at substantially the location of the sensing region 310 and the underlying material 304, the structure is locally compressed.

[0141] Even a very small deformation 312 can be converted into an easily detectable change in the mutual capacitance between electrodes 305, 306 that may have been printed on the film layers 102, 102B using, for example, printed electronics technology or some other production method, with one of the electrodes 305, 306 preferably serving as the driven / emitting electrode and the other electrode serving as the sensing / receiving electrode. The amount of force of a touch can be measured not only as a binary - type detection, since the measured signal is proportional to the force used, and the solution can be used as an analog force sensor instead of a "pure" touch sensor or in addition to a "pure" touch sensor.

[0142] The electrodes 305, 306 may have been electrically connected to the corresponding driven and measurement circuitry using, for example, traces through the material layers and one or more conductive vias (not shown for clarity) and / or Figure 2 a solution of. Those skilled in the art will realize that instead of isolated electrodes and a single (sub) volume of material 304, multiple electrodes or electrode patterns for, for example, grid - type sensing can be implemented separately.

[0143] The solution is applicable even if a conductive element such as a metal plate 308 is disposed on the film 102B and at least partially covers the sensing region 310. Thus, a metal - contact function can be implemented.

[0144] Material 304 may be selected to have a relatively high permittivity (e.g., greater than about 5 and / or a relative permittivity that exceeds the permittivity in material 104) to enhance the sensitivity of touch / force sensing.

[0145] In some embodiments, instead of or in addition to capacitive sensing, two opposing inductive loops may be configured at 304, 306 for, e.g., inductive sensing.

[0146] Figure 4 An embodiment of a multi-layer structure according to the present invention is shown at 400, which relates to field shaping by using active sensing or "feeding" elements and optionally shaping elements associated with functions that are not current-connected to the active elements. For example, the solution is suitable for touch and proximity (non-touch / non-contact) sensing purposes.

[0147] The film layer 102 may be provided with control and / or sensing or measuring electronic devices, such as the associated circuit or circuitry 406 (at least a part of such circuit / circuitry may also be located outside the structure 400 and connected thereto using suitable connection elements such as wires), and the electronic devices are preferably arranged, e.g., by means of printed electronics technology, and optionally printed on the trace current connection 405 on the layer 102 to, e.g., a capacitive or inductive sensing element 404 that defines a plurality of electrodes. On the other side of the intermediate layer 104, at least one field shaping element 408 is provided, such as a conductive element including a metal or other conductive material at layer 102B, and the at least one field shaping element is, for example, defined by the material of layer 102B or provided thereon using, e.g., suitable printing (e.g., a preferred method under printed electronics technology), deposition, lamination, or coating techniques.

[0148] By positioning one or more shaping elements 408 (in the case of multiple shaping elements, at least some of which may be, e.g., current-connected together and / or kept separate) at a distance from the sensing element 404 in different planes as in the depicted example, the electric or electromagnetic field or specifically the near field that can be considered a near-field antenna established by the element 404 can be flexibly controlled, such as attenuated, enhanced, shaped, and / or guided, in order to provide desired sensitivity characteristics for sensing purposes (e.g., touch sensing considering a predefined touch area defined on layer 102B and / or proximity sensing considering the sensing volume on layer 102B).

[0149] In addition to or instead of more “passive” field regulation provided by, for example, material selection, shape, size, positioning, etc. of one or more elements 408, at least one of the shaping elements 408 can be actively or dynamically controllable. Such controllability can be provided to the element, for example, by electrically connecting the element 408 to an electronic device 406 within or external to the structure 400.

[0150] Accordingly, a voltage and / or current can be supplied to the element 408 to control the field shaping characteristics of the element as needed, based on, for example, finding a dedicated optimum point through a sufficient testing process involving field measurements. Several layers of a multi-layer stack and their features can generally be connected together by using, for example, a stack / intermediate layer of a conductive material or by a solution such as Figure 2 as a solution.

[0151] In some embodiments, for example, antennas operable in the gigahertz frequency range (such as Bluetooth TM antennas) can be manufactured in a multi-layer structure according to a similar principle, thereby providing an antenna feed element (usually electrically connected to a control circuitry) that can be wirelessly (such as capacitively) coupled to a feeder and a remote / separate radiator. The resulting antenna structure can be made very thin and flexible and is suitable for use in various applications such as wearable electronic devices. The impedance matching between the feeder and the radiator can be achieved by appropriately designing the wireless coupling therebetween, without relying on discrete matching components.

[0152] Figure 5 An embodiment 500 of a multi-layer structure for multi-touch sensing according to the present invention is shown.

[0153] At least one constituent electrode pattern, such as a line or, for example, a diamond pattern and various other options, has been provided on both sides of the film layer 102. One constituent electrode pattern 510 is located on one side or surface facing the layer 104, and another constituent electrode pattern 508 is located on the opposite side or surface facing the environment of the structure (for example, the main structure or device or another material layer (not shown)) of the structure. These constituent patterns, which are different or similar to each other in terms of, for example, the shape used, their size, spacing, material, alignment, and / or orientation, together establish a desired overall sensing pattern such as an X-Y column grid and a row grid, where the columns and rows can be perpendicular to each other (as implied by the longitudinal side profiles of the line “ends” shown at 508 and the outermost lines at 510 in the figure), or arranged in some other configuration.

[0154] Alternatively or additionally, other surfaces or layers of the structure 500 can be used to carry an electrode pattern having a supported multi-touch sensing arrangement. For example, the film layer 102B can carry the electrode pattern 510 or 508 instead of the layer 102. In some embodiments, three, four (e.g., on both sides of two film layers 102, 102B), or more overlapping patterns can be provided in the structure 500.

[0155] In various embodiments, the patterns 508, 510 are configured for capacitive sensing such as capacitive touch or multi-touch sensing. Such touch inputs can then be used to control or specifically activate and deactivate different functions of, for example, the structure 500, the main body structure, or an external device such as an external device.

[0156] A control electronic device 506 such as a measurement circuit or circuitry can be connected to the pattern using, for example, conductor traces or optionally other generally conductive elements 505 printed using, for example, printed electronics technology. Alternatively or additionally, at least a portion of the electronic device 506 can reside outside the structure 500 and be connected to the outside using a suitable connection element such as a conductive wire.

[0157] In various embodiments, the structure 500 can be provided with a number of additional features that can be aesthetic, decorative, informative, other optical (light guiding or manipulation) features, electrical features, thermal management features, lighting features, etc. For example, in the illustrated scenario, a number of features 512 on either or both sides of the film layer 102B, or embedded in or defined by the film shape and / or material, can include, for example, decorative, informative, lighting (e.g., light sources, waveguides, etc.), and / or other (functional) features that are optionally superimposed on the underlying sensing features 508, 510 to assist the sensing arrangement, for example, by illuminating the sensing area on the layer 102B.

[0158] Arranging a number of film layers 102, 102B and potentially other layers in the structure facilitates the integration of various features in the structure, thus keeping their distances large enough from the perspective of reducing mutual interference or otherwise optimizing their functions. The several layers of the multi-layer stack can be connected together by using, for example, a stack / intermediate layer of a conductive material or by a solution such as Figure 2 of the solution.

[0159] Figure 6An embodiment of a multi-layer structure incorporating at least one integral functional coating in addition to a sensing function is shown at 600. It is noted, however, that the solution can also be used in isolation or other contexts without necessarily specifically incorporating sensing features in the structure. The coating can have aesthetic, decorative, informative, and / or other optical functions, such as a reflective function. However, the coating can have many additional functions, including protective, electrical, thermal, etc. Thus, a multi-functional coating can be provided on structure 600. Accordingly, in some embodiments, the coating can be considered to establish its own characteristics, or to be part of some other potential collective characteristics and impart desired qualities thereto.

[0160] In the example shown, structure 600 has been provided with, for example, a thermally and / or electrically conductive coating 608 on membrane 102, optionally as a post-processing task, but the coating can alternatively or additionally be provided on other surfaces and general elements of structure 600, as depicted by item 608B drawn in dashed lines and defining the exterior of the sidewall of structure 600 adjacent, for example, plastic layer 104. In fact, the coating can generally define one or more inner layers and / or outer surfaces of the structure. In some embodiments, most (if not almost all) of the outer surface of structure 600 can be provided by one or more coatings.

[0161] For example, coating 608 can include a conductive material such as a metal. The coating can be configured to provide electrical connections (e.g., power, communication, and / or control) to a number of electronic features 606, 606B, such as a light source (e.g., an LED) or other components arranged in the structure (e.g., its membrane 102).

[0162] Coating 608 can make direct electrical contact with features 606, 606B, or there can be intermediate conductive features, such as conductive vias, traces, rivets, springs, studs, rods, etc. arranged in structure 600 (note the vertical dashed lines). The conductive plating can be patterned (masked, post-deposition processing) to better suit, for example, current-carrying uses and enable at least a portion of the plating to be used as additional functional elements, such as antenna resonators, sensing electrodes, field formers, shields, etc. Membrane layer 102B can define or house many features not shown in the figure for clarity. In some embodiments, in addition to or instead of coating 608 on membrane layer 102, layer 102B can be covered or implemented with coating 608C. However, coating 608C on layer 102B (which can be on any side, but is shown on top) can provide electrical connections to features 606C, such as electrodes or other sensing elements, light sources, or other components, either directly or through intermediate connection members such as traces or conductive vias.

[0163] In structures such as LEDs or other lighting fixtures that incorporate reflectors or other optical features provided by a metal coating, the coating can be segmented, for example, along optically non-blocking lines to separate power rails and connected to an embedded portion through a membrane. The segmentation line can be hidden by using a non-conductive outer coating such as NCVM (non-conductive vacuum metallization). This enables the production of lighting fixtures or other items that have, for example, a conventional appearance but also control features such as electronic devices embedded in their structure. When, for example, an LED or other electronic device is embedded inside the structure, the same continuous plating or general coating that serves as a reflector and / or power distribution line can also be used to draw away heat, causing even the entire surface of the associated components to act as a large heat sink, thereby increasing LED light output and / or extending component life.

[0164] Coating 600 can refer to, for example, electroless plating (e.g., Cu, Ni), electroplating (e.g., Cu, Cr, Au, Ag), or a PVD (physical vapor deposition) coating that combines, for example, metallic and metalloid materials.

[0165] By using a metal coating, excellent thermal conductivity and electrical conductivity can be provided. However, the coating can be relatively easily applied to items and layers of various potentially complex shapes.

[0166] Considering the general applicability of different methods, for example, the thickness of a PVD coating can vary within a rather wide window, and masking can be utilized, for example, to limit the spread. Stacking different materials can enable the production of a coating with appropriate conductivity and visual appeal, for example, by stacking a copper plating and a chromium plating.

[0167] In various embodiments, a wet-processed plating can also be utilized in combination with an airtight sealing structure that is not affected by water intrusion, such as electroless copper or nickel with a chromium outer coating. Surface features such as connectors can be masked to prevent their exposure to the processing solution. Masking can be performed using a photoimageable spray mask, much like in printed circuit board manufacturing.

[0168] The plating or general coating used for shielding can be locally thickened to conduct heat away from the embedded electronic device. This requires sufficient process control to locally increase the layer thickness to a meaningful extent.

[0169] As mentioned above, in some embodiments, a patterned conductive coating or specifically a plating can be used to create a resonant structure for an embedded antenna, thereby cutting off the current contact between the emitting electronic device and the external environment. This can be beneficial, for example, in certain highly weather-exposed locations such as a flash housing or a "shark fin" antenna.

[0170] In various embodiments, a metal coating may be disposed on a body surface such as, for example, film layers 102, 102B, etc. The coated area may then be locally formed to exhibit a three-dimensional shape, such as a convex or concave (e.g., hemispherical dome or bowl) shape, such that the coating ruptures at the location of maximum local material deformation (dome / bowl edge or edge of a general shape). Thus, in addition to any potential aesthetic or informative (e.g., indicating a sensing area) function that the coating may have, one or more fracture lines may define the profile of a functional, potentially electrical feature such as a sensing, field shaping, or shielding feature.

[0171] Figure 7 An embodiment of a multilayer structure with an integrated trace shielding feature in accordance with the present invention is shown at 700.

[0172] The illustrated embodiment includes sensing features 706 such as sensing electrodes disposed on film layer 102. Feature 706 is shown on the top side of layer 102 and thus faces layer 104, but similar features may alternatively or additionally be located on the opposite side. In some usage scenarios, the top side may be referred to as the front side since the top side may face the user / usage environment, while the opposite side may be referred to as the back side and may then face, for example, a body device, a body surface, or a body structure.

[0173] However, it is clear that the applicability of the proposed shielding solution is not limited to any particular usage scenario or orientation, and thus terms such as "front" and "back" should not be considered as restricting the viability of the solution only to cases 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 additional electrical features, such as traces or other conductive features that connect feature 706 to a local or external control electronic device (not explicitly shown but has been visualized and discussed several times above with reference to other figures), which may drive feature 706 (provide voltage / current) and / or measure its characteristics, such as changes in capacitance, etc.

[0174] A shielding feature 710 including, for example, a metal or other conductive material has been disposed on film layer 102B: either by an appropriate method such as a selected printing or lamination method on the layer (e.g., as depicted, at the bottom side and thus facing layer 104 rather than the environment, and / or on the top side facing the environment and directly or through one or more additional top layers not drawn in the figure connected to the environment), or defined by the material and / or shape of layer 102B itself.

[0175] The shielding feature 710 overlaps with the underlying feature 708, and the underlying feature preferably substantially covers it from at least one selected direction. Feature 710 does not overlap with the actual sensing feature 706 to avoid reducing its sensitivity. However, in some other embodiments, overlapping may actually be desired to adjust, for example, the directivity of the sensing feature 706. When an object such as a finger or a stylus touches or approaches the structure 700 from the top or "front" direction, since the feature 708 is shielded by the feature 710, the object will not interfere with the sensing feature 706 through the feature 708 in the form of, for example, false detection or "ghost" detection.

[0176] Especially when using a relatively wide sensor trace (0.3 mm or wider) to enhance its durability during, for example, thermoforming or other processes when it is subjected to stretching, the sensor trace is prone to accidental touch detection and coupling to external electromagnetic noise.

[0177] Through the proposed shielding, the false touch tolerance can be improved, the electromagnetic noise coupled to such traces can be reduced, and it helps to keep the actual sensing features such as the electrode 706 relatively small (reducing space constraints, enabling a more compact layout of features, etc.).

[0178] The shielding feature 710 can be floating or grounded to, for example, the system / circuit ground (the ground connection is not explicitly shown in the figure but can be established through various measures and connection features discussed above). In some embodiments, the shielding feature can be actively driven (for example, a current is connected to the control electronics for such purposes).

[0179] Feature 710 can be any layer of conductive material, such as:

[0180] a) Printed conductive traces (cost-optimized fill rate per target), and / or

[0181] b) A printed layer of conductive ink, which can also form part of the decorative aspect of the structure.

[0182] It is also worth noting that when the feature 710 is implemented on the bottom side of the layer 102B as shown, in terms of, for example, electrostatic discharge (ESD) shielding, the feature is still far enough from the (top) surface of the structure 700.

[0183] Next, a selected still merely exemplary set of implementation options is listed to facilitate a skilled reader in determining the best choice for each specific usage scenario under consideration:

[0184] 1. The scenario shown, where traces and electrodes reside on the top side of one membrane layer (e.g., the back membrane from the perspective of the user / usage environment), and the ground shield resides on the bottom side of another front membrane layer (above the traces, i.e., between the sensing input area / volume and the traces).

[0185] 2. The same as above, but using a floating shield (not grounded).

[0186] 3. The same as above, but the signal is also driven to the shield (driven shield), which may increase, for example, liquid tolerance if the driven shield surrounds the sensor electrode.

[0187] 4. The sensor electrode is located, for example, on the bottom side of the first membrane layer (e.g., bottom layer 102), the ground electrode is located, for example, on the top side of another membrane layer (e.g., 102B) + an additional cover 705 is arranged on top of the said another membrane layer. The cover can comprise various materials or be composed of various materials, which include, for example, electrically insulating materials. The cover can include, for example:

[0188] a. A single board (e.g., wood);

[0189] b. Fabric; and / or

[0190] c. Molded materials or general plastic materials produced by, for example, a second injection surface injection mold (layer 104 can also be molded as discussed above).

[0191] 5. Two layers of touch surfaces or general sensing patterns on both sides (back / bottom membrane layer) of the membrane layer, which are protected by a ground shield on another membrane layer (front / top membrane layer) above the traces.

[0192] 6. A multi - layer touch surface pattern on the bottom side of the front membrane layer and either side of the back membrane layer. A ground electrode can be provided on the top side of the top / front membrane + a potential cover is added on top of the front membrane.

[0193] 7. The shield can be local or extend over the entire target surface with one or more openings provided, for example, for one or more sensing areas.

[0194] Figure 8A rough sketch of a test scenario for evaluating trace shielding according to an embodiment of the present invention is provided at 800. The multi-layer structure is provided with a number of embedded sensing features, such as electrodes 806 and associated connection traces 808 towards the control electronics, which can be arranged within or outside the structure through the necessary connections. Item 814 refers to a test object that mimics, for example, a human finger or other stylus, hovering over and / or contacting the structure above the trace 808. Item 810 refers to a possible (ground) shielding feature, such as a hatched shield (hatched lines), embedded in the structure as discussed above.

[0195] Figure 9A Shows the electric field in the scenario without an embedded trace shielding feature Figure 8 of the scenario.

[0196] Figure 9B Shows the electric field in the presence of trace shielding.

[0197] As can be readily detected from the Figure 9A and 9B generated by simulation, it was noted during testing that when protected by a shield, the effect of an object 814 placed on the trace 808 on the sensed signal is significantly weaker. Thus, if desired, smaller sensor electrodes can be used, thereby providing a better spatial density of sensing features and lower manufacturing costs. However, with proper shielding, wider traces can be utilized. The use of, for example, conductive vias can be reduced, as the traces can be accommodated by the same layer as the layer containing the actual electrodes. Since the shield can be positioned relatively far from the sensor traces (e.g., more than twice the trace width), the undesired capacitive coupling between the shield and the sensor traces can be reduced. The shielding solution also provides general enhanced protection against electromagnetic interference.

[0198] Figure 10 An embodiment of a multi-layer structure provided with, for example, multi-surface or multi-directional sensing capabilities for touch and / or proximity sensing is shown at 1000.

[0199] Considering, for example, a steering wheel and a control lever provided to a user such as a pilot or a passenger, referring to various devices including vehicles such as land vehicles / cars, airplanes, ships, spacecraft, etc. in a human-machine interface and its control panel or general control features or surfaces, there may be a need to provide touch sensors or general touch or proximity sensing capabilities that support simultaneous activation on both sides of the multi-layer structure without significant mutual interference.

[0200] With the proposed solution, additional substrate elements that define or accommodate at least one optionally printed shielding / grounding feature 1004, 1008, such as the film or film layer 102D, are arranged between two operating touch or general sensing surfaces provided in the film layers 102, 102B. Thus, the layer 102D integrates a shielding or specifically a ground plane that protects the top and bottom sides or direction sensing features 1002, 1006, 1010, 1012 from mutual interference and effectively isolates the top and bottom sides or direction sensing features from mutual interference.

[0201] As indicated in the figure, the layer 102C or other intermediate layer can accommodate a number of sensing features 1006. The film layer 102D can contain electrically insulating and / or conductive materials, such as plastics or specifically thermoplastic materials. The film layer can be flexible or substantially rigid. In some embodiments, the film layer 102D can be established from the same film as at least one other layer 102, 102B according to the Figure 2 embodiment (102C).

[0202] Although not shown in the figure, the outer surfaces of the films 102, 102B can carry sensing features. For clarity, electrical connections such as traces and control circuitry are omitted from the figure, but the considerations provided elsewhere herein regarding these generally also apply here. The sensing features 1002, 1006, 1010, 1012 can define at least a part of, for example, capacitive (such as self - capacitance or mutual - capacitance) sensing or inductive sensing.

[0203] Still only by way of example, one application area of the above - described sensing device may relate to control devices such as the steering wheel of a vehicle or other user input / user interface devices, where one side thereof can be equipped with a touch sensor or a touchpad, and the opposite side is equipped with a similar or different sensing arrangement.

[0204] For example, from the user's perspective, the so - called front face facing the user has a clear meaning for purposes such as menu scrolling, application browsing, and / or its selection. In the absence of predefined fixed operations, one or more rear sensors, such as a touchpad, may be more versatile. Still, in some embodiments, the rear sensor is only operable (or associated with any target function) after the selected front sensor has been activated (e.g., continuous input, such as the type of finger press necessary to accept rear input).

[0205] Figure 11 A flowchart of an embodiment of a method according to the present invention is shown at 1100.

[0206] At the start of a method for manufacturing a multi - layer structure, a startup phase 1102 can be executed.

[0207] During startup, necessary tasks may occur, such as material, component, and tool selection, acquisition, calibration, and other configuration tasks. Special attention must be paid to the fact that the individual element and material selections work together and are protected from damage during the selected manufacturing and installation processes, which is naturally pre-checked preferably on the basis of the manufacturing process specifications and component data sheets or by means of investigations and tests such as the produced prototypes.

[0208] Thus, equipment used, such as molding / IMD (in-mold decoration), lamination, bonding, (thermo)forming, casting, electronic device assembly, peeling, cutting, drilling, and / or printing equipment, can, for example, be brought to an operating state and tested at this stage.

[0209] At 1104, at least one optionally at least partially flexible substrate film is obtained, including, for example, plastic and / or one or more other materials for accommodating a number of features as discussed above, such as electronic devices like sensing electrodes, optionally associated circuitry, sensing response adjustment features, such as one or more additional electrodes, shields, field formers, etc., and / or other features, such as graphics, material layers, optical elements, etc. The substrate film can initially be substantially planar or, for example, curved.

[0210] In some embodiments, off-the-shelf components can be obtained, such as a roll or sheet of plastic film to be used as the substrate material. In some embodiments, the substrate film itself can first be produced or at least processed from a number of one or more selected starting materials by molding or other methods, optionally cut and / or coated. Optionally, the substrate film can be further processed at this stage.

[0211] For clarity, items 1108 - 1114 have been disclosed individually and in a specific order, but those skilled in the art should readily understand the fact that, depending on each specific use scenario, the mutual order of the items can be flexibly changed, e.g., the items can be performed alternately and repeatedly, integrated together, or divided into smaller wholes. However, one or more items can be selectively omitted from the implementation.

[0212] Accordingly, item 1108 refers to setting features such as conductive layers or regions, preferably but not necessarily, by one or more additive techniques such as printed electronics techniques, deposition, transfer lamination, etching, etc., on one or more substrate films, defining conductor lines (traces defining at least a part of a circuit design, for example), electrodes, and / or contact pads on any side or both sides thereof. For example, screen printing, inkjet printing, flexographic printing, gravure printing, or offset lithography can be utilized. Also, additional actions for culturing the one or more films can occur now or, for example, after setting additional features such as electronic components on the one or more films, and the additional actions involve, for example, coating or specifically plating and / or printing or generally setting decorative or informative graphics such as visual indicators on the films. A number of vias can be provided and the vias can be filled with, for example, one or more conductive materials or one or more general features, and / or a number of conductive features can be arranged through one or more films.

[0213] At 1110, a number of electronic components (e.g., various SMDs) such as off-the-shelf components can be attached, for example, by solder and / or adhesive to a target area on one or more films (e.g., conductor / contact areas / pads set by printing at 1108, for example). Alternatively or additionally, printed electronics and / or other viable techniques can be applied to actually fabricate at least part of a component directly on the one or more films, such as an OLED. Item 1109 refers to setting sub-assemblies such as system-on-chip assemblies on the one or more films.

[0214] At 1112, a number of functional features such as optical or other types can be provided by mounting or directly fabricating onto one or more substrate films.

[0215] At 1114, 3D formation of the one or more substrate films can occur using, for example, thermoforming or cold forming. As a result, the one or more associated substrate films will exhibit a desired three-dimensional (substantially non-planar) shape. Accordingly, one or more substrate films containing a suitable formable material can be shaped to better fit the target environment / device and / or better accommodate various features. Alternatively, formation can occur before setting at least some functional features such as electronic devices on the one or more films or, for example, after molding in cases where an established multi-layer stack is designed not to be damaged during such processing.

[0216] At 1116, at least one material layer, optionally including, for example, a thermoplastic material, is arranged on the one or more substrate films so as to cover, for example, one or more (first) functional features that have been provided thereon. As previously mentioned, for example, molding, casting, or other selected lamination techniques are typically applicable here. Also, as previously reviewed herein, materials of several different elasticities, permittivities, and / or permeabilities can be provided to affect and regulate sensing characteristics such as, for example, sensitivity.

[0217] In fact, for example, one or more substrate films or film layers can be used as inserts during an injection molding process. At least in some embodiments, one side of the substrate film can be free of molded plastic.

[0218] In the case of using, for example, two films / film layers, both of the two films / film layers can be inserted into their own half-molds such that a plastic layer is injected therebetween. Alternatively, the second film and potentially additional films can subsequently be attached to the assembly of the first film and the plastic layer by a suitable lamination technique.

[0219] Regarding the resulting total thickness of the obtained stacked multi-layer structure, taking into account manufacturing and subsequent use, this depends on, for example, the materials used and the relevant minimum material thicknesses that provide the necessary strength. These aspects must be considered on a case-by-case basis. For example, the total thickness of the structure can be about 1 mm or a few millimeters, but quite thick or thin embodiments are also feasible.

[0220] In some embodiments, as discussed in connection with Figure 2 the description of, a single film can be folded or generally bent so as to define multiple layers in a multi-layer stack.

[0221] Item 1118 refers to the provision of one or more additional features in the structure, such as various material layers, materials, components, internal connection features (for example, conductive features between / through one or more layers) and / or connectors. Further, various post-processing tasks can be performed at this stage. Additional layers can be provided on the multi-layer structure by lamination or, for example, a suitable coating (for example, deposition) procedure. The layers can have protective, indicative, and / or aesthetic value (graphics, colors, pictures, text, digital data, etc.) and contain, for example, textile, leather, or rubber materials instead of or in addition to plastic. Additional elements such as electronic devices can be mounted at one or more outer surfaces of the structure, such as at the outer surface of the substrate. The provided connector or connector cable type features can be connected to desired external connection elements, such as external connectors or connector cables of external devices, systems, or structures.

[0222] At 1120, the method execution ends.

[0223] The scope of the present invention is determined by the appended claims and their equivalents. Those skilled in the art will appreciate the fact that the disclosed embodiments are primarily constructed for illustrative purposes and that other arrangements applying many of the above principles can be readily prepared to best suit each potential use scenario.

Claims

1. An integrated multi-layer structure adapted for use in sensing applications, the multi-layer structure comprising: At least one plastic layer (104), the at least one plastic layer comprising an electrically insulating material, the at least one plastic layer having a first side and an opposite second side; At least one film layer (102, 102B), the at least one film layer disposed on both the first side and the second side of the at least one plastic layer; The at least one film layer (102) on the first side of the at least one plastic layer includes electronic devices that incorporate reactance sensing electronic devices for sensing one or more selected target quantities or qualities indicative of touch or proximity of an external object relative to the structure and converting the quantity or quality into a representative electrical signal, the sensing electronic devices including at least one electrode (305) and connection elements for connecting the at least one electrode to an associated control circuitry; and The at least one film layer (102B) on the second side of the at least one plastic layer includes one or more features including at least one conductive feature, the one or more features configured to adjust the sensing response of the sensing electronic devices on the first side of the at least one plastic layer, Wherein the at least one plastic layer (104) includes a volume of elastic material (304), the elastic material being locally disposed on the at least one electrode (305) of the sensing electronic devices and below a predefined sensing region (310) on the at least one film layer (102B) on the second side of the at least one plastic layer (104), the volume of elastic material (304) being more elastic than the surrounding material of the at least one plastic layer (104) and configured to be compressed in response to an external force (F) experienced by the at least one film layer (102B) on the second side of the at least one plastic layer (104) to enhance sensing sensitivity.

2. The multi-layer structure according to claim 1, wherein the at least one film layer on the first side of the at least one plastic layer includes an electrically insulating material (608).

3. The multi-layer structure according to any one of the preceding claims, wherein the sensing electronic devices include one or more elements fabricated and / or mounted on the at least one film layer.

4. The multi-layer structure according to claim 1, wherein the at least one electrode of the sensing electronic devices defines at least one electrode pattern (508, 510), elements of the pattern being disposed in one or more layers on one side or opposite sides of the at least one film layer on the first side of the at least one plastic layer.

5. The multi-layer structure according to claim 4, the pattern including a mutual capacitance sensing pattern of a plurality of transmitter electrodes and receiver electrodes or a self-capacitance sensing pattern of a plurality of sensing electrodes.

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

7. The multilayer structure according to claim 1, comprising a film (102C), a first section of the film defining at least a part of the at least one film layer (102) on the first side of the at least one plastic layer, and a second section of the film defining at least a part of the at least one film layer (102B) on the second side of the at least one plastic layer, wherein the first section and the second section are connected by a third section extending between the first section and the second section.

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

9. The multilayer structure according to claim 1, wherein the one or more features comprise a conductive material that forms at least a part of the film of the at least one film layer on the second side of the at least one plastic layer.

10. The multilayer structure according to claim 1, wherein the one or more features comprise at least one conductive and / or thermally conductive or insulating element defined by additional conductive or insulating material disposed on the film of the at least one film layer on the second side of the at least one plastic layer.

11. The multilayer structure according to claim 10, wherein the element extends locally on the film so as to define a selected pattern.

12. The multilayer structure according to claim 10, wherein the element extends over a major part or the entire surface of the film on at least one side of the film.

13. The multilayer structure according to claim 1, wherein at least one of the one or more features comprises a colored conductive material on the film of the at least one film layer on the second side of the at least one molded plastic layer.

14. The multilayer structure according to claim 1, wherein at least one of the one or more features is positioned adjacent to a predefined sensing area or sensing volume established by at least one electrode and another electrode or reference pattern provided in the structure, and / or is positioned at least partially superimposed on the conductive traces of the sensing electronic device, the at least one feature defining at least one functional element selected from the group consisting of: a. an electromagnetic shield (710) for shielding the sensing area, the sensing volume or the traces from external or internal electromagnetic perturbations or interferences; and b. an electromagnetic or electric field regulator (408) for adjusting the sensitivity of the sensing volume.

15. The multilayer structure according to claim 1, wherein the sensing electronic device and the one or more features define one or more sensing regions or volumes on both sides of the at least one plastic layer, and the structure further includes 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 defining an electromagnetic shielding or ground layer to reduce mutual electromagnetic interference between the sensing functions on both sides.

16. The multilayer structure according to claim 1, wherein the one or more features define electrodes or electrode patterns configured to establish a mutual capacitance sensing arrangement with the at least one electrode of the sensing electronic device, electrodes or electrode patterns 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 electronic device, touch or non-contact sensing regions, NCVM coatings, electroless plating-based coatings, PVD coatings, capacitive-coupled electromagnetic or electric field regulators, parasitic-coupling-based sensing features, reference electrodes, actively or passively coupled reference plates, ground electrodes, and floating ground, grounded, or circuit-grounded-connected ground electrodes.

17. The multilayer structure according to claim 1, wherein the relative permittivity of the elastic material is equal to or exceeds a threshold of 5 and / or exceeds the relative permittivity of the main material of the at least one plastic layer.

18. The multilayer structure according to claim 1, including a current connection element between the sensing electronic device and the one or more features, the current connection element being provided by at least one conductive element extending through the plastic layer or located at an edge or perimeter of the structure.

19. The multilayer structure according to claim 1, including at least one protective and / or decorative cover layer on the at least one film layer on the second side of the at least one plastic layer, wherein the cover layer includes veneer, wood, textile, fabric, bio-natural material, molded material, injection-molded material, or plastic.

20. A method (1100) for manufacturing an integrated multilayer structure for sensing applications, the method comprising: obtaining (1104) at least one film; arranging (1108, 1110, 1112) the at least one film with a reactance sensing electronic device for sensing one or more selected target quantities or qualities and converting the quantity or quality into a representative electrical signal, the sensing electronic device including at least one electrode (305) and a connection element connecting the at least one electrode to an associated control circuitry; arranging (1108, 1110, 1112) the at least one film with one or more features including at least one conductive feature, the one or more features being configured to adjust the sensing response of the sensing electronic device; and The at least one plastic layer, which is made of an electrically insulating material and is relative to the at least one film arrangement (1116), is configured such that the at least one plastic layer defines an integrated intermediate layer between the sensing electronic device received by the at least one film and one or more sensing response adjustment features. Wherein the at least one plastic layer (104) includes a volume of elastic material (304), the elastic material is partially disposed on at least one electrode (305) of the sensing electronic device and is disposed below a predefined sensing area (310) on at least one film layer (102B) on a second side of the at least one plastic layer (104). The volume of elastic material (304) is more elastic than the surrounding material of the at least one plastic layer (104) and is configured to be compressed in response to an external force (F) applied through the at least one film layer (102B) on the second side of the at least one plastic layer (104), so as to enhance sensing sensitivity.

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