IPC分类号：
F21V8/00 | G02B5/08
国民经济行业分类号：
C4350 | C3874 | C4090 | C3879
当前申请(专利权)人地址：
Oulunsalo, FI
发明人：
KERÄNEN, ANTTI | HEIKKINEN, TERO | KORHONEN, PASI | APILO, PÄLVI | HEIKKINEN, MIKKO | SÄÄSKI, JARMO | NISKALA, PAAVO | WALLENIUS, VILLE | TUOVINEN, HEIKKI | ASIKKALA, JANNE | SALMI, TANELI | KELA, SUVI | RUSANEN, OUTI | JUVANI, JOHANNA | SIPPARI, MIKKO | SIMULA, TOMI | RAUTIO, TAPIO | YRJÄNÄ, SAMULI | RAJANIEMI, TERO | KOIVIKKO, SIMO | HINTIKKA, JUHA-MATTI | SINIVAARA, HASSE | BRÄYSY, VINSKI | MIGLIORE, OLIMPIA | SEPPONEN, JUHA
代理机构：
CARTER, DELUCA & FARRELL LLP
代理人：
MICHAL, ESQ., ROBERT P.
摘要：
An integrated optically functional multilayer structure includes a flexible, substrate film arranged with a circuit design including at least a number of electrical conductors on the substrate film; and a plurality of top-emitting, bottom-installed light sources provided upon a first side of the substrate film to internally illuminate at least portion of the structure for external perception via associated outcoupling areas, wherein for each light source of the plurality of light sources there is optically transmissive plastic layer, produced upon the first side of the substrate film, said plastic layer at least laterally surrounding the light source, the substrate film at least having a similar or lower refractive index therewith; and reflector design including at least one material layer, provided at least upon the light source and configured to reflect the light emitted by the light source and incident upon the reflective layer towards the plastic layer.
技术问题语段：
The used substrates may be flexible, stretchable and printed materials organic, which is however, not always the case.|Various challenges may commonly emerge in the described and other illumination applications and use scenarios, however.|For example, undesired light bleed or leakage out of the structure or between different internal volumes and areas thereof may easily cause both functional and aesthetic issues not forgetting transmission losses from the standpoint of a desired optical path and original illumination target, as being easily comprehended by a person skilled in the art.|Yet, the perceivability of light sources themselves is one potential further issue.|Additionally, achieving sufficient resolution and in many cases, also dynamic or adaptive, control of internally transmitted and ultimately outcoupled light in terms of e.g., illuminated surface area shape, size, or location may at least occasionally turn out difficult with highly integrated structures.|In various solutions, controlling or specifically, improving e.g., the uniformity of light over its outcoupling surface, which may sometimes also span considerably large areas in relation to the overall dimensions of the structure or its selected surface, has been previously found burdensome.|Simply harnessing several light sources to more effectively lit up a joint target area or feature, such as an icon, may still cause illumination hot spots and additional leakage while also requiring more, often precious, power and space.|Obtaining decent mixing of brightness or colors may also be challenging and require a relatively long distance between the light source(s) and area or feature to be illuminated therewith especially in large area illumination applications, which adds to the size of the structure required or reduces the area that can be illuminated with proper mixing performance.|Still, some, in many ways generally favourable, light sources such as e.g., high-power LEDs may consume somewhat remarkable power (easily in the order of magnitude of about 1 watt or more) and eventually end up so hot that they degrade or break.|They may also damage adjacent heat-sensitive elements such as plastic substrates.|Adding multiple, potentially complex light guiding, incoupling, outcoupling, limiting or generally processing elements into the structure has, in turn, its own drawbacks such as increased space consumption, weight and other design constraints.|Maintaining the optical performance of the structure high, with reference to e.g., low leakage, loss, and similar objectives, may easily further limit the shape of the structure or included elements to ones otherwise sub-optimum in their intended use case.|Yet, if the optical features such as illumination features are to be combined with other features in the structure, the other features may negatively affect the lighting performance due to their shadowing or masking effect, for example, and occasionally also the optical features may prevent or complicate the implementation of the other features due to e.g., space constraints faced.|Manufacturing process-wise the adoption of various optical features in the structures may increase besides the overall process complexity also the amount of faced complications due to the added features' mutual (in)compatibility or (in)compatibility with the remaining materials and features as well as related process phases, considering e.g., overmolding, resulting in an increased fail rate/reduce yield.
技术功效语段：
[0029]For example, incoupling, transmission and (out)coupling of light may be effectively controlled and related optical efficiency and various other characteristics of interest, such as achieved illumination uniformity, optimized in a concerned optical structure by clever, joint configuration of the included materials and elements such light sources, with respect to e.g., their mutual positioning, orientation, dimensions and other characteristics. The solution also suits large area illumination applications particularly well and facilitates reducing or keeping the number of required light sources low, which has its clear advantages in terms of space savings, power consumption, structural and manufacturing complexity, weight, etc.
[0036]Adhesion between materials may be improved and e.g., wash-out issues may be reduced by utilizing multiple layers or multilayer elements so that the materials neighbouring the typically molded transmissive layer are selected so as to better survive molding and other processes as well as also attach to each other or the transmissive layer securely. For example, optionally co-extruded multilayer film(s) such as PC/PMMA film(s) could be used in a stack structure over and/or below the transmissive layer comprising e.g., PC resin then injection molded or otherwise produced on the PC layer of the multilayer film or between the PC layers of two multilayer films. Yet, also e.g., printed outcoupling elements could be provided on the PC surfaces with standard and many ways advantageous PC surface inks. In addition, using co-extruded multilayer films reduces adhesion issues between different material layers as the adhesion gained from the film co-extruding process is excellent. Different co-extruded material combinations with even better refractive index differences can be utilized.
权利要求：
1. An integrated optically functional multilayer structure suitable for large area dynamic illumination, comprising:
a flexible, substrate film arranged with a circuit design comprising at least a number of electrical conductors; and
a plurality of top-emitting, bottom-installed light sources provided upon a first side of the substrate film to internally illuminate at least a portion of the structure for external perception via associated outcoupling areas,
wherein for each light source of the plurality of light sources there is,
an optically transmissive plastic layer, provided upon the first side of the substrate film, said plastic layer at least laterally surrounding or neighbouring, the light source,
a reflector design comprising at least one material layer, provided at least upon the light source and configured to reflect, the light emitted by the light source and incident upon the reflective layer towards the plastic layer; and
at least one further, material layer, in contact with the reflector design, said at least one further material layer having a lower refractive index than the plastic layer.
2. The structure of claim 1, wherein the reflectance of the reflector design is at least locally about 75%, wavelengths of light.
3. The structure of claim 1, wherein the reflector design is configured optical emission path from at least one light source of the plurality of light sources so as to reflect light incoupled into the plastic layer from the light source and incident on the reflector design.
4. The structure of claim 1, wherein the reflector design is configured on or in the plastic layer to reflect and steer light emitted by at least one light source of the plurality of light sources and incident on the reflector design to propagate towards an outcoupling area for outcoupling the light at least from the plastic layer or the overall structure.
5. The structure of claim 1, wherein the reflector design at least locally comprises a material stack of a plurality of superimposed material layers having at least two mutually different refractive indexes.
6. The structure of claim 1, wherein the reflector design comprises at least one element selected from the group consisting of:
electrically conductive material;
metal;
thin-film coating; and
ink or paint.
7. The structure of claim 1, wherein one or more portions of the reflector design are located on a side of the plastic layer equal, opposite, and/or transverse to a side facing the first side of the substrate film hosting at least one light source of the plurality of light sources.
8. The structure of claim 1, wherein said at least one further material layer and said plastic layer being optically connected, so as to redirect at least part of the light emitted by at least one light source of the plurality of light sources, propagated within the plastic layer and incident upon the at least one further material layer back into the plastic layer by total internal reflection.
9. The structure of claim 8, wherein a layer of the at least one further material layer is a layer of the substrate film of multi-layer, type comprising also a hosting layer for the light source.
10. The structure of claim 8, comprising an intermediate layer between the plastic layer and a layer of said at least one further material layer, the intermediate layer comprising optically transmissive material, said intermediate layer and the layer of said at least one further material layer, hosting a number of elements such as optical elements, a circuit design or one or more electronic components, laminated upon the plastic layer.
11. The structure of claim 8, wherein at least portion of the reflector design and the at least one further material layer are mutually on the same, opposite, or both sides of the plastic layer.
12. The structure of claim 8, wherein a layer of the reflector design, a layer of the at least one further material layer, and the plastic layer are at least locally superimposed in terms of their materials so that the material of the layer of the at least one further material layer is stacked between the materials of the layer of the reflector design and the plastic layer.
13. The structure of claim 1, wherein the plastic layer defines a bend, and at least a portion of the reflector design is located essentially at an outer and/or inner perimeter thereof on the plastic layer.
14. The structure of claim 1, wherein at least a portion of the reflector design comprises a number of holes, such as a perforation, to enable incident light to propagate through for outcoupling, wherein the density of incidence and/or size of holes increases with distance from at least one of the plurality of the light sources.
15. The structure of claim 1, comprising at least one element, selected from the group consisting of:
a diffuser;
at least translucent or substantially transparent, essentially planar electrode;
printed graphics; and
protective exterior surface element.
16. The structure of claim 1, wherein the reflector design at least locally defines at least one collimating reflector surface, on a side of the plastic layer opposite to a side facing the first side of the substrate film hosting at least one light source of the plurality of light sources,
wherein at least one light source of the plurality of light sources is centered or off-centered in relation to the axis of symmetry of the collimating reflector surface.
17. The structure of claim 1, wherein the reflector design contains a locally treated, portion, such as a material stack portion or material layer portion, with altered reflective properties for light redirection and outcoupling.
18. The structure of claim 1, wherein the plastic layer locally defines a surface feature or a surface pattern, for outcoupling light that is internally incident thereon.
19. The structure of claim 1, comprising a number of outcoupling elements of spatially mutually varying density of incidence and/or dimensions, upon the plastic layer,
the density of incidence, thickness, and/or one or more other dimensions of the outcoupling elements increasing with distance from at least one light source of the plurality of light sources to respectively enhance outcoupling with distance.
20. The structure of claim 1, comprising a light outcoupling area on the plastic layer, wherein at least one light source of the plurality of light sources is located between at least a portion of the reflector design aligned substantially perpendicular to the light outcoupling area and the light outcoupling area, and said at least one light source of the plurality of light sources has been aligned in terms of its primary emission direction towards the at least portion of the reflector design.
21. The structure of claim 1, comprising a circuit board hosting at least one light source of the plurality of light sources and provided on the substrate film, a wall structure of optically transmissive material arranged at the periphery of the circuit board, and/or air gap or fill between the wall structure and the lightguide.
22. The structure of claim 1, comprising, in the optical path from at least one light source of the plurality of light sources towards the exterior of the structure and at the surface of or subsequent to the plastic layer, at least one element selected from the group consisting of: optical print layer, coating or film comprising opaque or translucent material relative to the light emitted by at least one light source of the number of light sources, optical mask, dented surface such as the surface of the plastic layer, layer of optically at least translucent if not transparent material with a refractive index lower than of optically subsequent, adjacent material such as air, layer of alternating higher and lower refractive index materials, perforated, holey or otherwise locally thinned or through-cut layer of opaque material, and adhesion promoting primer.
23. A multi-source multi-target illumination ensemble comprising two or more structures of claim 1, stacked together, configured to outcouple light from each of said two or more structures via their individual, at least partially non-overlapping, outcoupling areas on one or more surfaces of the ensemble and/or illuminated outcoupling elements in or on the ensemble.
24. The structure of claim 1, further comprising at least one of:
an overcoat at least partially covering a light emitting portion of at least one light source of the plurality of light sources,
wherein at least one light source of the plurality of light sources comprises a semiconductor, a packaged semiconductor, a chip-on-board semiconductor, bare chip, electroluminescent or a printed type light source, LED,
control circuitry, for dynamically and independently adjusting the intensity of light emission of at least two of the plurality of light sources,
wherein the optically transmissive plastic layer defines a hole therein to accommodate at least portion of at least one light source of said plurality of light sources,
wherein at least one of the number of electrical conductors of the circuit design is partially or essentially positioned on a side of the reflector design which faces away from the optically transmissive plastic layer and at least electrically, connects to the light source, or
wherein at least a portion of the reflector design is located between the optically transmissive plastic layer and the substrate film.
25. A method for manufacturing an integrated optically functional multilayer structure, comprising:
obtaining a flexible, substrate film, provided with a circuit design comprising at least a number of electrical conductors additively produced, on the substrate film;
arranging a plurality of top-emitting, bottom-installed light sources provided upon a first side of the substrate film;
providing laminating or 3D printing, for each light source of the plurality of light sources, an optically transmissive plastic layer upon the first side of the substrate film, said plastic layer at least laterally surrounding or neighbouring, the light source;
a reflector design comprising at least one material layer is provided and configured to reflect, the light emitted by the plurality of light sources and incident upon the reflector design; wherein
the optically transmissive plastic layer is at least partially provided as a pre-manufactured element initially separate from the first side of the substrate film.
26. The method of claim 25, comprising providing, at least one further material layer having a lower refractive index than the plastic layer so that said at least one further material layer and said plastic layer are optically connected, so as to redirect at least part of the light emitted by at least one of the plurality of light sources, propagated within the plastic layer and incident upon the at least one further material layer back into the plastic layer by total internal reflection.
27. The method of claim 25, comprising at least one step selected from the group consisting of:
laminating two or more layers included in the multilayer structure together by pressure-sensitive adhesive, optically clear adhesive, solvent, ink, heat, pressure, or hot melt;
additively producing such as printing or 3D-printing at least one layer such as the plastic layer, a layer of the at least one reflective layer, a further material layer, a lightguide, a light outcoupling element, a diffuser, and/or other optically functional element; and
providing a top-emitting light source of the plurality of light sources, on its side on the substrate film so that its contact pads face a direction transverse to the surface of the substrate film and are contacted by conductive adhesive provided on the substrate film electrically joining the contact pads with the circuit design, the conductive adhesive being at least partially surrounded on the substrate film by structural adhesive provided on the substrate film.
28. The method of claim 25, comprising interconnecting a plurality of modules together, wherein each module comprises:
at least one of
one or more light sources of the plurality of light sources;
at least a portion of the substrate film; and
the circuit design;
or
at least a portion of a layer of the reflector design and/or at least a portion of the plastic layer.
29. The method of claim 25, wherein the optically transmissive plastic layer is configured with at least one hole to accommodate at least one light source of said plurality of light sources.
30. The method of claim 25, wherein the optically transmissive plastic layer is arranged with at least portion of the reflector design prior to attaching the optically transmissive plastic layer and substrate film together either directly or via one or more intermediate layers.
技术领域：
[0002]The present invention relates in general to functional, integrated structures incorporating various functional features such as electronic, mechanical or optical elements. In particular, however not exclusively, the present invention concerns the provision of such structures comprising at least one or more optoelectronic light sources.
背景技术：
[0003]There exists a variety of different stacked assemblies and multilayer structures in the context of different functional ensembles e.g., in the field of electronics and electronic products. The motivation behind the integration of functionalities involving e.g., electronics, mechanical or optical features 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 casings, visual design of device housings, wearable electronics, personal electronic devices, displays, detectors or sensors, vehicle interiors, antennae, labels, vehicle electronics, etc.
[0004]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 produce electronics directly and additively to the associated substrate. The term “printed” refers in this context to printing techniques capable of producing electronics/electrical elements from the printed matter, including but not limited to screen printing, flexography, and inkjet printing, through a substantially additive printing process. The used substrates may be flexible, stretchable and printed materials organic, which is however, not always the case.
[0005]Furthermore, the concept of injection molded structural electronics (IMSE) involves building functional devices and parts therefor in the form of a multilayer structure, which encapsulates electronic functionality as seamlessly as possible. Characteristic to IMSE is also that the electronics is commonly manufactured into a true 3D (non-planar) form in accordance with the 3D models of the overall target product, part or generally design. To achieve desired 3D layout of electronics on a 3D 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 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 hiding the elements from the environment. Further layers and elements may be naturally added to the construction.
[0006]Optical features and functionalities to be provided in the afore-discussed integrated structures may include a number of light sources that are intended to illuminate e.g., selected internals of the structure or the environment of the structure. Illumination may have different motives per se, such as decorative/aesthetic or functional, such as guiding or indicative, motives.
[0007]For example, in some use scenarios the environment should be lit for increased visibility in gloomy or dark conditions, which may, in turn, enable trouble-free performing of various human activities typically requiring relatively high lighting comfort, such as walking, reading, or operating a device, to take place. Alternatively, the illumination could be applied to warn or inform different parties regarding e.g., the status of the structure or a related host device, or a connected remote device, via different warning or indicator lights and e.g., associated graphics. Yet, the illumination might yield the structure or its host a desired appearance and visually emphasize its certain areas or features by a desired color or brightness. Accordingly, the illumination could also be applied to instruct a user of the structure or its host device about e.g., the location of different functional features such as keys, switches, touch-sensitive areas, or other UI (user interface) features on the device surface, or about the actual function underlying the illuminated feature.
[0008]Various challenges may commonly emerge in the described and other illumination applications and use scenarios, however.
[0009]For example, undesired light bleed or leakage out of the structure or between different internal volumes and areas thereof may easily cause both functional and aesthetic issues not forgetting transmission losses from the standpoint of a desired optical path and original illumination target, as being easily comprehended by a person skilled in the art. Yet, the perceivability of light sources themselves is one potential further issue. In some applications, the light sources should preferably remain hidden or only weakly or occasionally exposed.
[0010]Additionally, achieving sufficient resolution and in many cases, also dynamic or adaptive, control of internally transmitted and ultimately outcoupled light in terms of e.g., illuminated surface area shape, size, or location may at least occasionally turn out difficult with highly integrated structures. In various solutions, controlling or specifically, improving e.g., the uniformity of light over its outcoupling surface, which may sometimes also span considerably large areas in relation to the overall dimensions of the structure or its selected surface, has been previously found burdensome. The same applies to spatial control of illumination and light outcoupling also more generally. This may be an important issue e.g., when the surface contains e.g., an icon or symbol to be evenly lit to indicate to a viewer external to the structure that a device functionality or status associated with the icon or symbol is active, for example. Simply harnessing several light sources to more effectively lit up a joint target area or feature, such as an icon, may still cause illumination hot spots and additional leakage while also requiring more, often precious, power and space. Obtaining decent mixing of brightness or colors may also be challenging and require a relatively long distance between the light source(s) and area or feature to be illuminated therewith especially in large area illumination applications, which adds to the size of the structure required or reduces the area that can be illuminated with proper mixing performance.
[0011]Still, some, in many ways generally favourable, light sources such as e.g., high-power LEDs may consume somewhat remarkable power (easily in the order of magnitude of about 1 watt or more) and eventually end up so hot that they degrade or break. They may also damage adjacent heat-sensitive elements such as plastic substrates.
[0012]Adding multiple, potentially complex light guiding, incoupling, outcoupling, limiting or generally processing elements into the structure has, in turn, its own drawbacks such as increased space consumption, weight and other design constraints. Maintaining the optical performance of the structure high, with reference to e.g., low leakage, loss, and similar objectives, may easily further limit the shape of the structure or included elements to ones otherwise sub-optimum in their intended use case.
[0013]Yet, if the optical features such as illumination features are to be combined with other features in the structure, the other features may negatively affect the lighting performance due to their shadowing or masking effect, for example, and occasionally also the optical features may prevent or complicate the implementation of the other features due to e.g., space constraints faced.
[0014]Manufacturing process-wise the adoption of various optical features in the structures may increase besides the overall process complexity also the amount of faced complications due to the added features' mutual (in)compatibility or (in)compatibility with the remaining materials and features as well as related process phases, considering e.g., overmolding, resulting in an increased fail rate/reduce yield. For example, if a material associated with a lower melt temperature (e.g., polymethyl methacrylate, PMMA) is utilized together with a higher melt temperature molding material (e.g., polycarbonate, PC), features printed or otherwise established on the lower melt temperature material may degrade or wash out during molding.
发明内容：
[0015]The objective of the present invention is to at least alleviate one or more of the drawbacks associated with the known solutions in the context of optically functional integrated structures and related methods of manufacture.
[0016]The objective is achieved with various embodiments of an integrated, functional multilayer structure and a related method of manufacture for providing the multilayer structure.
[0017]According to one aspect, an integrated optically functional multilayer structure suitable for large area dynamic illumination, comprises:[0018]a preferably flexible, optionally 3D-formable and thermoplastic, substrate film arranged with a circuit design comprising at least a number of electrical conductors preferably additively printed on the substrate film; and[0019]a plurality of preferably top-emitting and bottom-installed light sources provided upon a first side of the substrate film to internally illuminate at least portion of the structure for external perception via associated outcoupling areas,[0020]wherein for each light source of the plurality of light sources there is, optionally at least partially shared,[0021]optically transmissive plastic layer, optionally of thermoplastic material such as polycarbonate, provided such as laminated or produced upon the first side of the substrate film, said plastic layer laterally surrounding or at least neighbouring, optionally also at least partially covering, the light source, the substrate film optionally comprising material or material layer same as that of the plastic layer or at least having a similar or lower refractive index therewith; and[0022]reflector design comprising at least one material layer provided preferably at least upon the light source and configured to reflect, optionally dominantly specularly, the light emitted by the light source and incident upon the reflective layer preferably towards the plastic layer.
[0023]In a further aspect, a method for manufacturing an integrated optically functional multilayer structure, comprises:[0024]obtaining a preferably flexible, optionally 3D-formable and thermoplastic, substrate film, optionally a multi-layer film, provided with a circuit design comprising at least a number of electrical conductors, such as traces and/or contact pads, preferably additively produced, optionally printed, on the substrate film;[0025]arranging a plurality of preferably top-emitting and bottom-installed light sources provided upon a first side of the substrate film; and[0026]providing, optionally through laminating or producing, such as molding or 3D printing, for each light source of the plurality of light sources, optionally at least partially shared, optically transmissive plastic layer upon the first side of the substrate film, said plastic layer at least laterally surrounding or at least neighbouring, optionally also at least partially covering, the light source; wherein[0027]a reflector design comprising at least one material layer, optionally comprising a stack of material layers and/or a layer of electrically conductive and/or metallic material, is provided, optionally including printing, coating, laminating or molding, and configured to reflect, optionally dominantly specularly, the light emitted by the plurality of light sources and incident upon the reflector design, preferably towards the plastic layer.
[0028]The present solution yields different advantages over a great variety of previously applied solutions, naturally depending on each embodiment thereof.
[0029]For example, incoupling, transmission and (out)coupling of light may be effectively controlled and related optical efficiency and various other characteristics of interest, such as achieved illumination uniformity, optimized in a concerned optical structure by clever, joint configuration of the included materials and elements such light sources, with respect to e.g., their mutual positioning, orientation, dimensions and other characteristics. The solution also suits large area illumination applications particularly well and facilitates reducing or keeping the number of required light sources low, which has its clear advantages in terms of space savings, power consumption, structural and manufacturing complexity, weight, etc.
[0030]E.g., embedded mirror type reflectors may be arranged opposite or next to the light sources, using e.g., conductive, typically metallic materials or a multitude of varying refractive index layers, to enable efficient transmission and control of light within the structure. Yet, total internal reflection (TIR) capable interfaces may be additionally configured to supplement and, for example, stack with mirror reflectors for even more sophisticated and flexible control of light conveyance.
[0031]“Hidden until lit” effect may also be produced. For instance, graphical symbols provided in the structure, various components, or e.g., conductive traces can be obscured from external visual perception until a light source intended and targeted to illuminate them is activated.
[0032]Manufacturing-wise printing and other cost-efficient, flexible and versatilely controllable methods, such as various molding and coating techniques may be cleverly applied to manufacture desired features in addition to the use of ready-prepared elements such as films, components, or modules.
[0033]By properly configuring the light source(s) and e.g., the suggested reflector design, also mixing characteristics of light on the outcoupling surfaces along the transmissive plastic layer and the outer surface of the structure in general may be enhanced and thus a so-called mixing distance needed for achieving the desired mixing performance reduced.
[0034]Optical elements such as outcoupling elements may be integrally and monolithically formed in other elements such as material layers advantageously by locally deforming the associated materials, which provides very efficient optical solutions as well as yields space, material, and weight savings in addition to simplifying the structure and potentially also the manufacturing process among other benefits. For example, mirror effect provided by the reflector design may be locally destroyed to establish a light outcoupling element from the deformed portion, or material(s) at a TIR-enabling interface could be similarly treated to locally alter the interface's properties for enhanced scattering and/or interfering TIR, for instance.
[0035]A circuit design comprising electrical conductors to power the light sources, for instance, may be cleverly positioned behind the reflector design from the standpoint of light propagating in the transmissive plastic layer so that the circuit design causes no disturbances or at least reduced disturbances, such as diffusion or absorption, to the light propagation.
[0036]Adhesion between materials may be improved and e.g., wash-out issues may be reduced by utilizing multiple layers or multilayer elements so that the materials neighbouring the typically molded transmissive layer are selected so as to better survive molding and other processes as well as also attach to each other or the transmissive layer securely. For example, optionally co-extruded multilayer film(s) such as PC/PMMA film(s) could be used in a stack structure over and/or below the transmissive layer comprising e.g., PC resin then injection molded or otherwise produced on the PC layer of the multilayer film or between the PC layers of two multilayer films. Yet, also e.g., printed outcoupling elements could be provided on the PC surfaces with standard and many ways advantageous PC surface inks. In addition, using co-extruded multilayer films reduces adhesion issues between different material layers as the adhesion gained from the film co-extruding process is excellent. Different co-extruded material combinations with even better refractive index differences can be utilized.
[0037]The suggested multilayer may be modular and put together using a plurality of mutually different and/or similar modules providing different features to the aggregate structure. For instance, IMSE piece or cell type modules, which are preferably shaped (e.g. hexagonal/honeycomb cell) so that they can be fixed to each other straightforwardly, like the pieces of a puzzle, may be utilized. Some module(s) may contain more features or functionalities, more complex functionalities, harder to implement functionalities, or functionalities of several types such as general electronics and/or optoelectronics such as light sources, while some other module(s) may be simpler and contain mainly e.g., passive optical (transmissive material, reflector, mask, etc.) or other features conveniently manufacturable and usable for scaling the size of the structure, for example. The modules may support snap-fit joints or crimp fixing for easy mutual fixing, for example. Besides a modular single structure, several multilayer structures may be joined, optionally stacked, together to form even larger ensembles. Accordingly, modularity may be cleverly provided on different levels and resolutions.
[0038]Different embodiments of the present invention may be versatilely utilized and included in different applications, e.g., in electronic or electronics-containing appliances including but not limited to computers, tablets, smartphones, other communication devices, wearables, av equipment, optical devices, domestic appliances, vehicles, displays, panels, medical devices, smart clothing, furniture, pieces of art, etc.
[0039]Various additional utilities different embodiments of the present invention offer will become clear to a skilled person based on the following more detailed description.
[0040]The expression “a number of” may herein refer to any positive integer starting from one (1).
[0041]The expression “a plurality of” may refer to any positive integer starting from two (2), respectively.
[0042]The terms “first” and “second” are herein used to distinguish one element from other element(s), and not to specially prioritize or order them, if not otherwise explicitly stated.
[0043]The exemplary embodiments of the present invention presented herein are not to be interpreted to pose limitations to the applicability of the appended claims. The verb “to comprise” is used herein as an open limitation that does not exclude the existence of also un-recited features. The features recited in various embodiments and e.g., dependent claims are mutually freely combinable unless otherwise explicitly stated.
具体实施方式：
[0060]FIG. 1 generally illustrates, at 100, via a cross-sectional sketch, an embodiment of a multilayer structure in accordance with the present invention.
[0061]The multilayer structure includes at least one substrate film 102, which is preferably of flexible and 3D-formable (3D-shapeable) material, such as thermoformable (plastic) material. As being comprehended by a person skilled in the art, instead of a single, optionally monolithic film 102, there could be a multilayer and/or multi-section construction type film 102a with mutually different layers at least in places, for instance, including also a hosting layer for the electronics. Such multilayer film 102a could manufactured by co-extruding, for example, as a part of an embodiment of a method contemplated hereinlater.
[0062]Item 108 refers to at least one, preferably also thermoplastic while at least optically transmissive layer preferably provided by molding upon the substrate film 102. Optionally, the layer 108 may have been produced essentially between the substrate film 102 and possible further element(s) or generally, material layer(s), such as at least one further layer or film different from or similar to the film 102, for example. Item 108 may alternatively refer to a plurality of stacked, preferably still thermoplastic and/or integrated, layers that may have been optionally produced by multi-shot molding. The layer 108 should be able to convey light at least having regard to selected wavelengths such as substantially all or selected wavelengths of visible light, or generally at least part of the wavelengths emitted by the included light source(s), which typically while not necessarily include visible wavelengths.
[0063]The layer 108 comprises a first side and a related first surface 108a that may be targeted towards the use environment of the structure and e.g., a user 113 of the structure located in such environment, depending on the application. Yet, the layer 108 comprises an opposite second side and associated second surface 108b essentially facing at least one instance of the film 102 and potentially a host device or structure, for instance. In alternative embodiments, however, the surface 108b may be the one that essentially faces the use environment and e.g., user therein instead of or in addition to the surface 108a.
[0064]As the layer 108 is indeed supposed to convey or guide light, it shall comprise optically at least translucent, optionally substantially transparent, material, wherein the optical transmittance of the overall thermoplastic layer may in some use scenarios preferably be at least 50%, but the desired transmittance may indeed radically differ between all possible use scenarios. In some embodiments at least about 80% or 90% transmittance could be preferred for maximizing the light output from the structure and low losses, while in some other scenarios lower figures could be quite sufficient if not even advantageous, if e.g., light leakage related issues are to be minimized. The transmittance may be defined or measured in a selected direction, e.g., main direction of light propagation and/or in a transverse direction (i.e., thickness direction) to the surface of the substrate film 102, having regard to the wavelengths of interest, typically including visible wavelengths as discussed above.
[0065]Suitable translucency or optical attenuation of the layer 108 could in some embodiments be reached by employing scattering elements such as particles in the used material, for example. When the number of scattering elements is increased, scattering/diffusion and half power angle, as a possible measurable indicator, are increased as well while luminous transmission through the layer will generally decrease. Correspondingly, increasing layer thickness generally increases scattering/diffusion properties such as the half power angle and decreases transmission.
[0066]In terms of applicable materials, the layer 108 may generally comprise, for example, at least one material selected from the group consisting of: polymer, organic material, biomaterial, composite material, thermoplastic material, thermosetting material, elastomeric resin, PC, PMMA, ABS, PET, copolyester, copolyester resin, nylon (PA, polyamide), PP (polypropylene), TPU (thermoplastic polyurethane), polystyrene (PS or GPPS, general-purpose-polystyrene), TPSiV (thermoplastic silicone vulcanizate), and MS resin.
[0067]The substrate film 102 may optionally comprise material or material layer same as that of the layer 108 or at least having a similar or lower refractive index therewith. Accordingly, the resulting interface 102, 108 may be made optically transparent or enabling a total internal reflection (TIR) type function, respectively, for light arriving at the interface from withing the layer 108.
[0068]In some embodiments, tinted or more strongly colored resin as the material of layer 108 may provide a feasible option for limiting undesired light leakage within and outside the structure 100 to close elements or generally distances, and hide the internals such as light source 104 or other circuitry from external perception. Originally optically substantially clear base material such as PC or other plastic resin could be thus doped with a colored masterbatch. In many use scenarios wherein the structure 100 should be only e.g., few millimeters or a centimeter thick in total, whereupon the thermoplastic layer 108 should be even thinner, using about 2-4 mm, such as 3 mm, thick layer of plastic resin provided with a selected masterbatch (e.g. white or desired selective wavelength resin, optionally also e.g. IR (infrared) resin that might find use e.g., IR remote control applications) in a desired concentration (e.g. let-down ratio of about 1%) for establishing the layer 108, may provide quite satisfying results. Generally, in many embodiments in the context of the present invention, a feasible let-down (dosing or doping) ratio is indeed about 5%, 4%, 3%, 2%, 1% or less. For example, suitable industrial grade masterbatches for the purpose are provided by Lifocolor™. The so-called “hidden until lit” effect may be achieved for the light source 104 or other features included in the structure 100, for instance, by adding translucent, e.g. a selected color exhibiting, masterbatch in the injection molded base resin constituting the layer 108.
[0069]Item 124 refers to an overcoat at least partially covering a light emitting portion of the light source, said overcoat layer comprising optically transmissive material optionally having a higher refractive index than the plastic layer.
[0070]The overcoat 124 may include encapsulant, glob top or other conformal coating, such as a Illumabond™ or Triggerbond™ for light shaping or other processing, protecting and/or securing purposes, for instance. The used substance may be dispensed on top of selected circuitry such as the light source 104 or other electronics included in the structure. The substance may be substantially clear (transparent), for example. Alternatively, it could be colored and/or translucent. In some embodiments, a specific optical function or feature such as a lens may be provided by the encapsulant. The lens could be diffusive, Fresnel or e.g., collimating, for example. Additionally, or alternatively, a pre-made lens or generally optical component is possible to include in the structure as well, either on the surface or embedded.
[0071]The substrate film 102 and/or further film(s) or generally material layer(s) included in the multilayer structure may comprise at least one material selected from the group consisting of: polymer, thermoplastic material, electrically insulating material, PMMA (Polymethyl methacrylate), Poly Carbonate (PC), flame retardant (FR) PC film, FR700 type PC, copolyester, copolyester resin, polyimide, a copolymer of Methyl Methacrylate and Styrene (MS resin), glass, Polyethylene Terephthalate (PET), carbon fiber, organic material, biomaterial, leather, wood, textile, fabric, metal, organic natural material, solid wood, veneer, plywood, bark, tree bark, birch bark, cork, natural leather, natural textile or fabric material, naturally grown material, cotton, wool, linen, silk, and any combination of the above.
[0072]Depending on the embodiment in question, the substrate film 102 and/or further film(s) or layers potentially included in the structure may comprise or be of optically substantially transparent or at least translucent material(s) having regard to the wavelengths of interest, such as visible light, with associated optical transmittance of about 80%, 90%, 95%, or more, for example. This may be the case especially when the substrate film 102 is configured in the structure 100 so as to effectively convey or pass light emitted by the light source 104. Yet, in some embodiments the used substrate film 102 could be substantially opaque, black and/or otherwise exhibitive of dark colour, to block incident light from passing through it (mask function).
[0073]The thickness of the film 102 and optionally of further film(s) or layer(s) included in the structure 100 may vary depending on the embodiment; it may only be of few tens or hundreds of a millimeter, or considerably thicker, in the magnitude of one or few millimeter(s), for example.
[0074]The thickness of the layer 108 may also be selected case-specifically but thicknesses of few millimeters, such as about 3-5 millimeters, may be applied. In some embodiments, only about two millimeter thickness or less, potentially only e.g., few tenths of a millimeter, could be sufficient if not optimum, while in some other embodiments the thickness could be considerably more as well, e.g. about 1 cm or more at least in places. The thickness may indeed locally vary. The layer 108 may optionally comprise recesses or internal cavities for light guiding, processing, and/or thermal management purposes, for instance, in addition to accommodating various elements such as electronic or optical elements.
[0075]The film 102, the layer 108 as well as further layers such as films, coatings, etc. of the structure may be essentially planar (width and length greater, e.g., different in the order of magnitude, than the thickness). The same generally applies also to the overall structure as illustrated in the figs even though also other, non-planar shapes are fully feasible.
[0076]Item 104 refers to a light source preferably of optoelectronic type. The light source 104 may be or comprise a semiconductor, a packaged semiconductor, a chip-on-board semiconductor, a bare chip, electroluminescent and/or a printed type light source, preferably a LED (light-emitting diode) or OLED (organic LED). The light source 104 may be of top-shooting and bottom installed, of or side-shooting type. Still, multi-side shooters or bottom-shooters may be utilized depending on the characteristics of each particular use case.
[0077]Still packaging-wise, the light source 104 could be optionally of flip-chip type. In some embodiments, the light source may contain multiple (two, three, four, or more) light-emission units such as LEDs packaged or at least grouped together. For example, a multi-color or specifically RGB LED of several LED emitters could be provided within a single package.
[0078]The light source 104 is provided, such as fabricated (optionally printed with reference to e.g., OLED) or, in the case of at least partially ready-made component, mounted on the substrate film 102, preferably on a first side 102f and associated surface thereof, which faces the transmissive layer 108 instead of the opposite second side 102s and surface of the film 102. Yet, additional host layer(s) such as films may be included in the structure for accommodating further elements such as light sources or other electronics. For mounting, e.g., adhesive (conductive or non-conductive) may be generally applied.
[0079]The light source 104 may be at least partially embedded in the material of the layer 108 during overmolding or otherwise preparing of the layer 108 thereon.
[0080]The layer 108 may include one or more light outcoupling areas 112 on any side of the layer 108, such as first 108a or second 108b side, through which the light originally emitted by the light source 104, incoupled into and propagated within the layer 108 is to be outcoupled to the surrounding layer(s) and/or the environment. The light source 104 may be positioned as desired having regard to the respective outcoupling area(s) 112. The source 104 may be located close to an area 112 so that even a related direct optical path, without reflections, is available from the emission surface(s) of the source 104. Alternatively and perhaps more commonly, the source 104 is a located aside and farther away from the associated outcoupling area(s) (e.g., out of LOS, line-of-sight, from the area or external environment adjacent the area) due to a variety of reasons, which may include hiding or masking the source 104 better from external perception or enhancing the uniformity of illumination (e.g., brightness and/or color(s)) on the area(s) 112 by letting the light emitted by the source 104 to propagate within the layer 108 and at neighbouring layers or material interfaces, primarily or also by reflections, for a longer distance and period in favour of improved mixing, for example. FIG. 1 shows only a single light source 104 for improved clarity, and in many embodiments one source 104 might be sufficient if not advantageous, but as being easily comprehended by a person skilled in art, there are countless embodiments e.g., in the field of large area illumination that might benefit from including several sources 114 on the same or different substrates (and utilizing shared or separate transmissive layer(s) 108 and/or reflector design(s) 110) in the structure, either having at least partially joined or separate outcoupling area(s)112 associated with them, affecting the positioning and orientation of the light sources 104.
[0081]Item 106 refers to a circuit design in the form of one or more at least electrical, optionally additively produced such as screen printed or otherwise printed, conductors such as traces, electrodes, and/or contact pads, which may optionally further act as thermal conductors. The conductors may be used for power and data transfer purposes, for example, between the elements of the structure 100 and/or with external elements. The circuit design 106 may provide control signal and/or power to the light source 104 from a controller and power circuit(s), respectively, among other uses. The circuit design 106 may connect to an external device via e.g., wiring- or connector-containing exterior surface or edge of the structure 100. Additionally or alternatively, wireless connectivity may be applied based on e.g., electromagnetic or particularly, inductive coupling among other options. The circuit design(s) 106 may be arranged on or in the substrate film 102 and/or other host(ing) elements such as material layers of the overall multilayer structure. There may be a number of local or partial circuit designs 106 in the structure, e.g., on different layers or hosts thereof, which may at selectively connect together at least operatively if not physically, and establish a greater circuit design spanning several elements such as layers of the structure. Some elements such as conductors (e.g., traces) may be physically located as distributed or shared between two or more layers of the structure (a first portion residing on/in one layer and a second portion on/in another layer, for instance). Accordingly, such elements may be considered part of several local circuit designs (e.g., on different layers) or of the greater circuit design.
[0082]The light source 104 may be emissive as indicated by the dotted lines 104a (top shooting), 104b (side shooting) extending from the source 104 into the transmissive layer 108.
[0083]Item 110 and sub-items 110a, 110b, 110c (see FIG. 2) refer to a reflector design, which may also be of single-part or multi-part (multi-portion) construction. Two or more parts of the multi-part construction solution do not have to physically directly connected as they may reside on the opposite sides 108a, 108b of the layer 108, for instance or otherwise separated by a distance. Yet, any of the parts, or portions, may include one or more material layers e.g., as stacked, as their constituent elements.
[0084]Accordingly, the reflector design 110 comprises least one material layer. The reflector design 110 is configured to reflect, preferably dominantly specularly, the light originally emitted by at least one light source 104 and incident upon the reflector design 110.
[0085]One or more portions of the reflector design 110, or the whole design 100, may be located on a side of the plastic layer equal (see reflector/reflector portion 110a for illustration), opposite (see reflector/reflector portion 110b for illustration), and/or transverse (see especially reflector/reflector portion 110c for illustration) to a side facing the first side 102f of the substrate film 102 hosting the light source 104.
[0086]In some embodiments, as illustrated by a scenario depicted at 150 (a sub-sketch of FIG. 1), at least part of the conductors 106a establishing the circuit design 106 may be configured to lie external to the light transmitting plastic layer 108, reflector design 110 and potential further intermediate layer(s), such as layer 114, thereby lying e.g., on a side and optionally surface of the reflector design 110 that faces away from the light transmitting (optically transmissive) plastic layer 108, instead of a side facing the light transmitting plastic layer 108. Generally, at least portion of the conductors may be thus located away from a volume spanning the layer 108 and possible intermediate space to the reflector design 110 even if the conductors 106a are configured to transfer e.g., data or energy to/from electronics such as the light source 104 optionally at least essentially or partially residing within the volume.
[0087]Likewise, at least portion of the substrate film 102 itself may be positioned to lie on a side of at least portion of the reflector design 110e that is opposite to the side actually facing and potentially directly attaching to and contacting the optically transmissive layer 108. The stacking order of the reflector design 110e and substrate film 102 may be thus at least locally reversed from that of the main illustration provided e.g., in FIG. 1. For example, one or more conductors of the design 106 may be provided on the substrate film 102, parallel to its surface (e.g., adjacent or under electronic components such as the light source 104), which is also depicted in the sketch. Instead of directly producing the layer 108 on the substrate film 102 (and potentially on one or more conductors of the circuit design 106 and/or the light source 104 already provided to the film 102) by molding, for instance, the layer 108 could be premanufactured, optionally with features 103 such as holes for accommodating light sources and/or at least portion of the reflector design 110e, prior to attaching to the substrate film 102, which is indicated in the figure by two arrow symbols. Suitable lamination technique based on e.g., adhesive, heat and/or pressure could be utilized for the purpose.
[0088]Accordingly, optical and indirectly also electrical efficiency of the arrangement may be enhanced as the conductors at least partially if not mostly or essentially fully positioned at a distance from the transmissive layer 108 will then not interfere or will at least interfere less with the optical path of light emitted by the light source 104, propagating in the transmissive layer 108 and at least occasionally reaching the reflector design 110 and reflecting therefrom. Otherwise, the conductors could cause excessive undesired phenomena to the incident light including diffusion and absorption, for example. In certain embodiments though, the effect of the conductors on the incident light could be additionally or alternatively harnessed to a useful purpose such as optical effect (diffusion, attenuation, or shadowing, etc.).
[0089]In preferred embodiments, the reflector design 110 or at least a portion thereof is typically configured to reflect the incident light that has previously propagated typically inside the (transmissive) layer 108 to at least roughly towards, or back towards, the layer 108 to prevent e.g., undesired light outcoupling from the structure 100 or light leakage, for instance. In some embodiments, the reflector design 110 may comprise at least a portion that is, in turn, configured to direct the incident light to alternative direction such as outside the layer 108 or the whole structure 100.
[0090]Further, the reflector design 110 may be configured on or in the layer 108 to reflect and steer light emitted by the light source 104 and incident on the reflector design 110 to propagate towards an outcoupling area 112, 112a, 112b, 112c. In some embodiments to be discussed also hereinafter, the reflector design 110 may be configured to direct the incident light more towards a surface normal of the layer 108 for outcoupling the light at least from the layer 108 or the overall structure.
[0091]Indeed, with reference to e.g., sketches in FIGS. 2 and 3, for example, the reflector design 110 may be configured at least in connection with light incoupling from the light source 104.
[0092]The reflector design 110 or at least portion thereof may be located (110a), 110b, 110c on a direct optical emission path from the light source 104. Further, the reflector design 110 may be located or comprise a portion 110b that is located upon and/or opposite to the light source 104 (e.g., on the opposite side 108a of the layer 108 with respect to the light source 104), aside from and/or under the light source 104 so that the design 110 receives and reflects and at least part of the light emitted by the light source 104.
[0093]As illustrated, by way of example only, in FIG. 3 at 300, the reflector design or a portion thereof 110b may be configured so as to reflect light incoupled into the layer 108 from the light source 104 and incident on the reflector design 110 to align more with a lateral plane of the layer 108 substantially transverse to a surface normal of the layer 108.
[0094]Generally, a portion of the reflector design 110, 110a, 110b, 110c may be located at least partially embedded in the layer 108, and/on the surface 108a, 108b of it.
[0095]And as well illustrated, by way of example, in FIG. 2 at 200, the light source 104 may be located between at least a portion of the reflector design 110c that is preferably aligned substantially perpendicular to the light outcoupling area and the light outcoupling area 112. The light source 104 may be then aligned in terms of its primary emission direction to point at least partially towards the reflector design 110c. For example, the light source, e.g., side-emitting LED or other source, may be aligned so as to point e.g., about 180 deg away from the direction of the outcoupling area, 112, 112a, 112b, 112c (shortest path).
[0096]Accordingly, the distance between the light source 104, or light sources 104 in a typical scenario of several light sources utilized, and associated outcoupling area(s) 112, 112a, 112b, 112c may be kept short and reduced from more conventional solutions as the respective optical distance defined by a path the light emitted by the light source(s) 104 actually take prior to outcoupling 112 is increased by roughly two times the distance D illustrated in the figure, i.e. the distance between the reflector design 110c and each concerned light source 104. This turns into smaller applicable multilayer structures and/or larger outcoupling area(s) 112, 112a, 112b, 112c obtainable with decent light mixing characteristics, depending on the preference set for the application as being understood by a person skilled in the art.
[0097]The reflectance of the reflector design 110 is preferably at least locally about 75%, more preferably at least about 90%, and most preferably at least about 95% at selected, optionally essentially all visible, wavelengths of light such at least part of the wavelengths emitted by the source(s) 104.
[0098]To achieve e.g., sufficient reflectivity, the reflector design 110 or some other optically functional element included in the structure at least locally preferably comprises at least one element selected from the group consisting of:[0099]electrically conductive material, such aluminum, silver, gold, zinc, copper, or beryllium;[0100]metal, optionally metal particles, further optionally provided upon or within the substrate film or further film or a further film or layer included in the structure;[0101]a plurality of stacked, superimposed material layers of at least two mutually different refractive indexes, optionally defining a Bragg mirror;[0102]thin-film coating, optionally PVD (physical vapor deposition) coating; and[0103](reflective) preferably printable ink or paint.
[0104]Accordingly, through utilization of conductive materials such as metals in one or more layers of the reflector design 110, a so-called skin depth of the reflector design 110 and the whole underlying structure can be kept small and thereby, reflection efficiency high. Conductive materials and metals may be provided e.g. in a film, paint, ink, or extrusion (e.g., metal particles in a host material such as plastics) process. In principle, any practical metallization procedure may be applied to provide the metal(s).
[0105]Alternatively or additionally, a plurality of stacked layers (potentially even tens or hundreds of layers) may be applied to establish a jointly effective, preferably integral, reflective structure, such as a Bragg mirror. In such structures, layers of different refractive indexes may alternate in a sequence. For example, two materials of different refractive index may be configured to alternate in a multilayer reflector stack constituting at least portion of the reflector design 110. At each interface between the two material layers a Fresnel reflection is advantageously created. When the optical path length difference between subsequent layers is half of the wavelength (i.e., each layer is quarter wavelength thick), the reflections interfere constructively (zero/360 deg phase shift between reflections). For example, plastic polymer materials may be utilized in the multilayer reflector stack, such as e.g. PMMA and PC or PS. The stacked integral multilayer element may in some embodiments also include substrate film 102 and/or other film(s) or generally layer(s) or feature(s), such as item(s) 114, 116, the subject being discussed further hereinbelow in more detail.
[0106]The stack included in the reflector design 110 may be realized as an optionally ready-made multilayer film. Alternatively, several, optionally stacked, material layers of the reflector design 110 may be produced by a selected coating technique (e.g., PVD or electroplating on plastics) on a substrate, such as the substrate film 102. Alternatively or additionally, e.g. (multiple) co-extrusion process may be applied.
[0107]Item 114 briefly refers to at least one further, optionally additively produced by printing, for example, material layer, optionally stacked and further optionally in contact with the reflector design 110. The at least one further material layer 114 preferably has a lower refractive index than the layer 108. For example, the layer 114 could comprise PMMA when the layer 108 is of PC.
[0108]The at least one further material layer 114 and the layer 108 may be optically connected, optionally also physically adjacent, so as to redirect at least part of the light emitted by the light source propagated within the plastic layer 108 and incident upon the at least one further material layer 114 back towards and into the plastic layer by total internal reflection (TIR) at their interface. In general, and e.g., in cases wherein the reflector design 110 is stacked with and located e.g., behind the interface of layers 108, 114 on the optical path, it 110 may effectively cooperate with the interface and reflect e.g. the remaining light that has passed through the interface e.g. at angles lower than a related critical angle and is thus incident on the reflector design 110 behind.
[0109]At least a layer or other portion of the reflector design 110, a layer of the at least one further material layer 114, and the layer 108 may thus be at least locally superimposed in terms of their materials so that the material of the layer of the at least one further material layer 114 is stacked between the materials of the reflector design 110 and the layer 108.
[0110]Generally, at least portion of the reflector design 110, 110a, 110b, 110c and the at least one further material layer 114 may mutually reside on the same, opposite, or both/several sides 108a, 108b of the layer 108.
[0111]The at least one further material layer 114 may optionally comprise or consist of e.g., optically clear adhesive (OCA) or primer.
[0112]Generally, utilizing e.g., patterned selective low(er) refractive index materials e.g., in layer 114 or elsewhere, light propagation in the structure may effectively, both technically and cost-wise, controlled. For instance, with large structures having one or more light sources 104, selectively producing light guiding and light guiding enhancing such as reflective (border) structures may turn out advantageous. Light guiding structures such as item(s) 108, 110, 114, 116 can be constructed e.g., sector-wise having different optical properties and e.g. lengths or generally dimensions.
[0113]In some embodiments, an integrated multilayer construction, such as a multilayer film 102a, may be included in the structure 100 as a prefabricated or in situ fabricated element.
[0114]The multilayer film 102a may include a plurality of, e.g. two, stacked and attached, optionally co-extruded, layers one of which may be or establish the substrate film 102 or similar layer for hosting the light source 104 as well as the circuit design 106 and potential additional electronics or other elements, while at least one other layer may be at least one layer of item 114 and/or of the reflector design 110, 110a (which may itself be a multilayer material stack as discussed hereinbefore), for example, among other options.
[0115]In some embodiments, an intermediate layer 116 may be provided in the structure, e.g. between the layer 108 and a layer of the at least one further material layer 114 (if present), and/or between the layer 108 and reflector design 110, 110b, on the first side 108a of the layer 108.
[0116]The intermediate layer 116, embodied e.g., as a film, may also act as a substrate (surface) for various elements such as electronic components incl. light sources. The intermediate layer 116 may comprise optically transmissive material optionally same as that of the layer 108 or has at least a similar refractive index therewith. Previous considerations provided herein regarding the substrate film 102, may also be generally applied to the intermediate layer 116 as being appreciated by a person skilled in the art.
[0117]The intermediate layer 116 and the layer of said at least one further material layer 114 and/or at least one layer of the reflector design 110, 110b may further be constituents of a multilayer construction such as multilayer film 116a, further optionally being a co-extruded multilayer film.
[0118]Items 120, 122 refers to one or more elements such as material layers optionally at or at least close (preferably within one or two material layers) to any of the exterior surfaces of the structure on either side or both sides 108a, 108b of the layer 108. They 120, 122 may include films, coatings, prints, plastic materials, natural materials (leather, etc. as listed e.g., in connection with applicable substrate film/film materials hereinbefore). The item(s) 120, 122 may host other features (e.g., electronic components) or layers, and be thus also considered substrate(s) depending on the embodiment. Preferably the items 120, 122 are at least translucent in places, comprise optionally filled (with at least translucent material) (through-)holes or cover only limited area(s) to enable light outcoupling from the structure. Different lamination, printing, coating, molding, or extrusion methods may be utilized for providing any of the items 120, 122, for example.
[0119]Item 118 refers to one or more outcoupling elements the stru