FIELD OF THE INVENTION

Generally the present invention relates to electronics, associated devices, structures and methods of manufacture. In particular, however not exclusively, the present invention concerns manufacturing of multilayer structures containing multiple functional features.

BACKGROUND

There exists a variety of different stacked assemblies and structures in the context of electronics and electronic products.

The motivation behind the integration of electronics and related products may be as diverse as the related use contexts. Relatively often size savings, weight savings, cost savings, or just efficient integration of components is sought for when the resulting solution ultimately exhibits a multilayer nature. In turn, the associated use scenarios may relate to product packages or food casings, visual design of device housings, wearable electronics, personal electronic devices, displays, detectors or sensors, vehicle interiors and vehicle electronics, antennae, labels, etc.

Electronics such as electronic components, ICs (integrated circuit), and conductors, may be generally provided onto a substrate element by a plurality of different techniques. For example, ready-made electronics such as various surface mount devices (SMD) may be mounted on a substrate surface that ultimately forms an inner or outer interface layer of a multilayer structure. Additionally, technologies falling under the term “printed electronics” may be applied to actually produce electronics directly and additively to the associated substrate. The term “printed” refers in this context to various printing techniques capable of producing electronics/electrical elements from the printed matter, including but not limited to screen printing, flexography, lithography and inkjet printing, through a substantially additive printing process. The used substrates may be flexible and printed materials organic, which is however, not always the case.

The concept of injection molded structural electronics (IMSE) actually involves building functional devices and parts therefor in the form of a multilayer structure, which encapsulates electronic functionality and possibly other functionality.

In an IMSE process different features of desired function may be first applied to at least one substrate film. Then the one or more films may be inserted in an injection molding cavity, where hot melt state material is injected upon the film or between the films, thus becoming an integral part of the resulting multilayer structure.

One interesting characteristic of IMSE is also that the electronics is often, not always, manufactured into a 3D (non-planar) form in accordance with the 3D models of the overall target product, part or generally design. To achieve desired layout of electronic or other elements on a substrate and in the associated end product, the electronics may be still provided on an initially planar substrate, such as a film, using two dimensional (2D) methods of electronics assembly, whereupon the substrate, already accommodating the electronics, may be optionally subsequently formed into a desired three-dimensional, i.e. 3D, shape and subjected to overmolding, for example, by suitable plastic material that covers and embeds the underlying elements such as electronics, thus protecting and potentially also hiding the elements from the environment.

When a multilayer structure is loaded with various electronics, it may not always function completely in isolation, i.e. autonomously. Instead, various power, data and/or control connections may have to be provided thereto, which typically requires provision of e.g. electrical connectors and related wiring.

In some cases, when one or more functional elements, such as electronic, optical or optoelectronic components, were to be included in a multilayer structure, their integration has turned out difficult during actual stacking of the layers by e.g. molding or lamination, as the target configuration in terms of e.g. desired layer shapes, dimensions, element positioning and alignment, both generally and mutually, has been tricky to achieve using the contemporary methods. Yet, some of the functional elements to be provided in the structure have been found sensitive to a number of phenomena such as pressure or temperature subjected to them during the stack-up or e.g. specifically molding process, or e.g. 3D forming process, which has rendered their early insertion in the structure challenging if not impossible due to an associated high risk of breakage while connecting, fabricating, or forming the layers.

In some occasions measures trying to integrate all functional features in desired target locations within a multilayer structure to be constructed already while sandwiching the layers has generally resulted in tedious, complex and slow, manufacturing processes with potentially low yield, whereupon unique alternative techniques for providing functional features in a multilayer structure have raised considerable interest.

Further, in some scenarios a need to lock down the internals and functionalities of the multilayer structure already upon construction or integration of the layers has been found limiting from the standpoint of different uses some more generally applicable structure could ultimately find.

SUMMARY

The objective of the present invention is to at least alleviate one or more of the above drawbacks associated with the existing solutions in the context of integral multilayer structures and functional elements or features such as electronics embedded therein.

The objective is achieved with various embodiments of a method for manufacturing an integrated multilayer structure and related multilayer structures in accordance with the present invention.

According to one embodiment of the present invention, a method for manufacturing an integrated multilayer structure, comprises:

obtaining a substrate film of selected material and having a first and second side, said substrate film optionally being flexible and/or comprising plastic and/or composite material;

providing at least on the first side of the substrate film one or more first functional features, optionally including decorative, informative, other optical, protective, electrical and/or electronic features such as conductors and/or electronic components;

arranging at least one layer, preferably at least partially comprising electrically substantially insulating and/or conductive material, optionally plastic material, upon at least the first side of the substrate film;

removing, optionally selectively and locally, at least a portion of the substrate film so that space, optionally comprising a through-hole in the substrate film, is released in the structure, wherein a detachment-enhancing feature provided to the substrate film is configured to facilitate the removal of said at least portion such that the adjacent remaining film material, if any, the arranged layer and the first functional features are preserved and preferably remain substantially intact; and

providing at least one second functional feature into the space released for use so that the at least one second functional feature at least functionally, preferably optically, electrically and/or electromagnetically, connects with at least one of said one or more first functional features.

According to one other embodiment, an integrated multilayer structure, comprises:

a substrate film having a first and second side, said substrate film optionally being flexible and/or comprising plastic material,

one or more first functional features provided at least upon the first side of the substrate film, optionally including decorative, informative, other optical, electrical and/or electronic features such as conductors and/or electronic components;

at least one layer, optionally comprising or consisting of plastic material, arranged, optionally molded, upon at least the first side of the substrate film; and

a detachment-enhancing feature provided relative to at least a portion of the substrate film to facilitate the removal of the at least portion such that the adjacent film material, if any, the arranged layer and the first functional features remain substantially intact during the removal, while space, optionally defining a through-hole in the film, is released in the structure to enable at least partially filling the space with one or more second functional features preferably having a functional connection with the one or more first functional features.

According to a further embodiment, an integrated multilayer structure comprises:

a substrate film having a first and second side, said substrate film optionally being flexible and/or comprising plastic and/or organic material,

one or more first functional features provided at least upon the first side of the substrate film, optionally including decorative, informative, other optical, electrical and/or electronic features such as conductors and/or electronic components;

at least one layer, optionally plastic material, arranged, optionally molded, upon the first side of the substrate film, wherein space, such as a hole or cavity, is defined in the structure, comprising a through-hole in the film, preferably obtained by locally removing at least a portion of the substrate film; and

at least one second functional feature provided into the space so that it at least functionally, preferably electrically or electromagnetically, connects with one or more of the first functional features.

Still according to a further embodiment, an integrated multilayer structure comprises:

at least one material layer, optionally of molded plastic material,

one or more first functional features provided to the at least one material layer by a substrate film, optionally including decorative, informative, other optical, electrical and/or electronic features such as conductors and/or electronic components, said one or more first functional features optionally defining a hole; and

at least one second functional feature preferably at least partially provided into the hole so that it at least functionally, preferably electrically or electromagnetically, connects with one or more of the first functional features.

Various considerations provided herein concerning the embodiments of the multilayer structure may be flexibly applied to the embodiments of a manufacturing method mutatis mutandis, and vice versa, as being appreciated by a skilled person. Yet, various embodiments and related features may be flexibly combined by a person skilled in the art to come up with preferred combinations of features generally disclosed herein.

The utility of the present invention arises from a plurality of issues depending on the embodiment.

Generally, it is made possible, by the suggested selective delamination or complete removal of a substrate film, to add one or more new functional features, including but not limited to optics, haptics, electronics, etc., by means of attaching or directly producing the associated elements in the multilayer structure subsequent to construction of the multilayer structure already containing the film and a number of features as well as a molded or casted layer provided thereon. Alternatively or additionally, various embodiments of the present invention similarly enable convenient establishing of an external connection such as electrical, mechanical, or optical connection to the structure internals. Space for accommodating the added features may be released, i.e. established and/or revealed, for instance, by the use of different applicable detachment-enhancing measures in the structure as well as by at least selective removal of the substrate film from the structure. The added features may at least functionally connect with one or more other features already present in structure. Accordingly, new functionalities may be dynamically and flexibly added to and embedded in the multilayer structure that has been at least partially constructed earlier.

Also thermal management, or specifically heat management, of the overall structure or particular features provided therein may be enhanced by various embodiments of the present invention as applicable heat conducting material features (solid elements, gaseous matter, etc.) may be supplied to the structure and e.g. into contact with internals thereof via the released space. Certain features such as high power LEDs (associated power could be in the magnitude of about one or several, even tens of, watts, for instance) cannot be usually straightforwardly in-molded e.g. in plastic or some other material provided upon the substrate film due to high heat generation during their operation. By various embodiments of the present invention, also such LEDs or other high power/heat generating elements may be provided in the multilayer structure so that their heat conduction can still be satisfactorily managed, using e.g. separate housing and/or enhanced heat transfer.

As a practical example having regard to provision of one or more connectors as added functional features, in some embodiments, an electrical or other connector structure, or simply a connector, for providing electrical, e.g. power and/or communications, connection between the internal, embedded features of the multilayer structure and an external device, system or structure may be reliably and also with good visual quality integrated, secured and embedded within a functional, e.g. circuit design and various electronics-containing multilayer structure generally manufactured in accordance with e.g. IMSE principles. Potentially problematic later piercing of the substrate film or application of other methods requiring proceeding through the film material either by the connector itself or by e.g. a specific hole-making tool may be therefore avoided when preferred.

As a further practical example, good adhesion of a substrate film to adjacent elements or layers is commonly highly preferable in insert molding and specifically e.g. in the field of IMSE. However, by embodiments of the present invention selective (on selected areas) or complete delamination of the film may be exploited to connect or add additional functional features to IMSE, which could not be done easily or at all using e.g. one-shot molding. When delamination is achieved so that e.g. electrical conductors or other features remain attached to the side of molded plastics while the substrate film is removed on at least selected areas additional features can be flexibly and conveniently post assembled to the already established multilayer structures. Additional features can be for example light-emitting components such as LEDs, pressure sensors, capacitive sensors, haptic features such as touch detection sensors, etc.

Still further, features requiring precise positioning or e.g. alignment with other elements may benefit from the present invention. For example, LEDs or other light sources may have to be aligned with other functional or specifically optical features such as a lens, reflector, prism, or lightguide provided in the multilayer structure, which was traditionally considered difficult due to inaccuracies caused to the positioning and alignment of the mutually aligned features by resolution and related constraints set by used manufacturing techniques such as molding/lamination of layers. Now, final positioning or alignment may be done after inaccuracy-causing manufacturing phases.

Further, in some embodiments, advantageous combinations of soft (deformable), e.g. elastic, and essentially rigid or stiff materials may be come up with. Accordingly, functionalities such as combined pressure sensor—capacitive button may be created. For instance, conductive soft material or generally soft functional feature can be injection molded or otherwise provided in the structure using e.g. a second molding shot following the first shot used to produce the harder and/or stiffer material on the film and removal of film. In some embodiments, soft material may be attached to the structure via or in the removed portion e.g. by adhesive. In other words, structure and function combining arrangements not practically feasible earlier may be obtained.

In the above and other use scenarios it is commonly considered beneficial to introduce the substrate film at least locally with one or more detachment-enhancing features so that the film, or in some embodiments films, can be separated from one or more features originally provided on the film, e.g. graphic print, conductive or otherwise functional ink, so that the features remain adhered to e.g. injection molded resin or other layer provided on the film while the film is at least selectively removed. In the space made available due to at least local removal of the film, the exposed internals such as functional features may be subjected to post processing and the space may be filled with additional functionality that preferably at least operably connects with the existing functionalities. Among other options, the detachment-enhancing feature may include e.g. a protective layer or feature provided on a film surface. The protective layer or similar feature may be chosen so that it has relatively poor (or at least poorer) adhesion to other neighboring materials such as molded material or e.g. graphic and functional ink, whereupon it can be peeled off or otherwise extracted preferably together with the matching portion of the substrate after the provision of the resin or other layer.

Different embodiments of a manufacturing method suggested herein are still somewhat straightforward to comprehend and take into use, and what is considered beneficial, do not necessitate adopting completely new or different manufacturing technologies just for adding the desired functionality in the multilayer structure. Forming of the film(s) to a desired 3D shape e.g. after provision of features such as conductors or further electronics thereon (while the substrate film was still substantially planar), may additionally reduce or obviate a need for potentially tedious and error prone 3D assembly of electronics on a substrate. By the embodiments of the present invention, functional elements, e.g. various electronics, optics, or e.g. (piezo) haptics, which are sensitive to forces or other implications arising from 3D forming or other phases of establishing the multilayer structure (e.g. molding or casting-induced heat or pressure), may be cleverly provided in the structure afterwards.

The obtained multilayer structure may be used to establish a desired device or module in different host elements such as vehicles or specifically (in-)vehicle electronics, lighting devices including vehicle lighting, user interfaces in vehicles and elsewhere, dashboard electronics, in-vehicle entertainment devices and systems, vehicle interior or exterior panels, intelligent garment (e.g. shirt, jacket, or trousers, or e.g. a compression garment), other piece of wearable electronics (e.g. wristop device, headwear, or footwear), personal communications devices (e.g. smartphone, phablet or tablet) and other electronics. The integration level of the obtained structure may be high and desired dimensions such as the thickness thereof small.

The used film(s) and generally material layers may contain graphics and other visually and/or tactilely detectable features thereon, whereupon the films/layers may have aesthetic (decorative) and/or informative function in addition to hosting and protecting the electronics. The film(s)/layer(s) may be translucent or opaque at least in places. They may exhibit a desired color or comprise portions exhibiting a desired color to the corresponding portions of the structure. The obtained multilayer structure may thus incorporate one or more color/colored layers that optionally determine graphics such as text, pictures, symbols, patterns, etc. These layers may be implemented by dedicated films of certain color(s), for instance, or provided as coatings (e.g. through printing) on existing film(s), molded layer(s), and/or other surfaces. Exterior film(s) of the multilayer structure may be configured to establish at least a portion of outer and/or inner surface of the associated host product or host structure.

Various visible or visual features such as graphical patterns or coloring may be provided underneath the exterior surface of the structure so that the features remain isolated and thus protected from environmental effects at least by the thickness of the hosting substrate films and optionally of the molded layer depending on which side the film was provided relative to the environmental threat. Accordingly, different impacts, rubbing, chemicals, etc. that could easily damage e.g. painted, printed or mounted surface features do not affect or reach the features. The material layers such as the ones defined by substrate or other films may be easily manufactured or processed, optionally cut, into a desired shape with necessary characteristics such as holes or notches for exposing the underlying features such as the molded material.

The expression “a number of” may herein refer to any positive integer starting from one (1).

The expression “a plurality of” may refer to any positive integer starting from two (2), respectively.

The terms “first” and “second” are herein used to distinguish one element from other element, and not to specially prioritize or order them, if not otherwise explicitly stated.

When “different” or “various” embodiments of the multilayer structure, related method of manufacture, or features included therein are referred to herein, the embodiments are to be considered mutually supplementary and may thus be realized in common embodiments, unless being otherwise explicitly stated or otherwise clear to a person skilled in the art that the concerned solutions are mutually clearly exclusive alternative solutions for implementing the very same feature of the solution.

Different embodiments of the present invention are disclosed in the attached dependent claims.

