Electronic device comprising a multilayer stack

Abstract

An electronic device (100) includes an electronic substrate (10) having at least one light-emitting device (12), a cover substrate (20) having a graphic pattern with at least one window (22), and a thermoplastic layer (30) between the electronic substrate (10) and the cover substrate (20). A multilayer laminate (40) of the electronic device (100) is formed by laminating the electronic substrate (10) and the cover substrate (20) together to increase the plasticity of the thermoplastic material (30m), with protruding electronic components (11, 12) facing the thermoplastic layer (30). At least the thermoplastic layer (30) is heated to a lamination temperature (Tl). The electronic components (11, 12) are pressed into the heated thermoplastic layer (30) by lamination to embed the electronic components (11, 12) within the thermoplastic material (30m).

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to multilayer electronic devices and methods of manufacture. [Background technology]

[0002] Electronic devices generally can include multiple layers of electronic components, graphic components, conductive materials, circuitry, etc. Typically, the manufacture of electronic devices involves a multi-step process sequence during which the layers are gradually formed on a substrate and overmolded with plastic to form a multi-layer structure with embedded electronics, e.g., by thermoforming, injection molding, blow molding, rotational molding, etc. Thus, the electronics are hermetically sealed and protected from the environment.

[0003] For example, in-mold electronic devices can be made by backside injection molding of thermoformed films. However, including both electronics and graphics within thermoformable and / or injection-moldable products typically requires careful selection of materials and processes. Incorrect selection or technique can result in optical defects that make the circuitry and components visible to the user. One solution to this problem is to use a thicker substrate. However, this leads to higher costs because thicker substrates are much more expensive. Furthermore, injection molding locally applies higher shear stresses to components that protrude from an otherwise flat surface. Such components can become dislodged as a result of the forces, leading to yield loss. Components oriented perpendicular to the material flow are most susceptible to shear. Strong glues (underfills) can help, but they may require a separate manual application step and may introduce other component contact issues. Segmentation of the molded layer is another major issue with backside injection molding, as one mold per material is required. For example, segmentation can be used to create light guides that do not exhibit optical crosstalk. Separate islands of the same material must be connected by molding to fill them; otherwise, each island would require its own mold. Therefore, localized light guides are difficult to create by molding. Finally, accessing electrical circuits using rigid or flexible connectors is difficult when backside injection molding is used. Such connectors are formed, for example, by applying a laser through a specific portion of the plastic part or by creating flexible contacts that protrude from the mold. However, during molding, stresses are greatest at the transition points from the molded portion and the connector, making them prone to damage. This can be partially avoided by using flexible contacts, for example, copper / polyimide, but these can be relatively expensive. Summary of the Invention [Problem to be solved by the invention]

[0004] There remains a need for further improvements in the fabrication of multilayer electronic devices. [Means for solving the problem]

[0005] Aspects of the present disclosure relate to methods of manufacturing electronic devices and related products, such as those obtained by such methods. As described herein, the methods include combining various substrates, e.g., having electronic and / or graphic layers, into a multi-layer stack. For example, electronic substrates typically include electronic components disposed on and protruding from at least one side of the electronic substrate.

[0006] In some embodiments, the electronic component comprises at least one light-emitting device for emitting light. In this way, the electronic substrate can provide, for example, backlighting for other or further layers. In some embodiments, a cover substrate having a graphic pattern is used. For example, the graphic pattern can comprise one or more layers of (opaque) material. The graphic pattern can comprise one or more regions for transmitting at least a portion of the emitted light from each light-emitting device.

[0007] In some embodiments, the electronic substrate and the cover substrate can be manufactured with separate functions, thereby avoiding material interference that occurs when building on a single film. Preferably, a thermoplastic layer is provided between the electronic substrate and the cover substrate. For example, the thermoplastic layer comprises a thermoplastic material that can transmit light. Most preferably, the backlighting passes from the electronic substrate through the thermoplastic layer and through the window in the cover substrate to reach the user.

[0008] Advantageously, a multilayer laminate can be formed by combining an electronic substrate and a cover substrate by laminating a thermoplastic layer with the electronic component protruding opposite the thermoplastic layer. By heating at least the thermoplastic layer to a lamination temperature to increase the plasticity of the thermoplastic material, the electronic component can be more easily pressed into the heated thermoplastic layer by lamination to embed the electronic component within the thermoplastic material. It will be appreciated that in this manner, the electronic substrate and the cover substrate can be separated between the two sides of the laminate. Additionally, forming a multilayer laminate can avoid several sequential forming steps and the need to align multiple films within a mold.

[0009] Optionally, the multi-layer laminate can be thermoformed into a desired shape, e.g., a three-dimensional shape. Alternatively, or additionally, the laminate can optionally be further reinforced by (reverse) injection molding or otherwise overmolded. By first laminating the layers together using a thermoplastic layer, the component, electronic circuitry, and / or graphic layer can be protected from further processing, for example, mitigating the risk of shear forces during thermoforming and injection molding.

[0010] In some embodiments, the thermoplastic layer has a structured set of properties, such as mechanical stiffness, absorption, optical properties such as light guiding, blocking, light reflection, or other electrical or thermal properties, such that when the laminate is constructed from three films, differentiation of these properties can be defined within the thermoplastic layer prior to lamination.

[0011] These and other features, aspects, and advantages of the devices, systems, and methods of the present disclosure will become better understood from the following description, appended claims, and accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1A] FIG. 1A illustrates the fabrication of an electronic device. (power) [Figure 1B]FIG. 1B shows an electronic device. [Figure 2A] FIG. 2A shows a cross-sectional view of the thermoforming of the multi-layer laminate. [Figure 2B] FIG. 2B shows the multi-layer laminate inside a thermoforming mold. [Figure 3A] FIG. 3A shows backside injection molding of a multi-layer laminate. [Figure 3B] FIG. 3B shows backside injection molding of a multi-layer laminate. [Figure 4A] FIG. 4A shows a schematic cross-sectional view of an electronic device. [Figure 4B] FIG. 4B shows a schematic cross-sectional view of the electronic device. DETAILED DESCRIPTION OF THE INVENTION

[0013] The terminology used to describe particular embodiments is not intended to limit the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly dictates otherwise. The word "and / or" includes any and all combinations of one or more of the associated listed items. It will be understood that the words "comprises" and / or "comprising" specify the presence of the stated features but do not exclude the presence or addition of one or more other features. When a particular step of a method is referenced as following another step, it will be further understood that it may follow immediately after the other step, unless otherwise specified, or that one or more intermediate steps may be performed prior to performing the particular step. Similarly, when a connection between structures or components is described, it will be understood that the connection may be established directly or through intermediate structures or components, unless otherwise specified.

[0014] Aspects of the present disclosure include multilayer laminates in which the electronic and graphic substrates are split between two sides of the laminate. Typically, an elastomer is disposed between the two substrates to form a single segmented layer with patches / islands of different (optical) properties. For example, rigidity is achieved through material and three-dimensional shape selection, eliminating the need for backside injection molding. Advantageously, components for light management, sensing, actuation, and operation of the device are embedded within an elastomer layer that flows sufficiently during thermoforming to avoid stress in the components, regardless of orientation. Additionally, this allows for easy external contact of printed electronics in an inexpensive and straightforward manner. In some embodiments, graphics are printed on a relatively thin film, and electronic functionality is provided on another film. For example, patterned conductors and dielectrics, as well as components, are assembled, potentially in multiple layers. It will be appreciated that both films can be manufactured separately and printed with materials useful in optical management, light reflection, blocking, or absorption.

[0015] In some embodiments, two or more films are combined into a laminate, and the printed materials are forced toward each other by laminating a third elastomeric layer at a temperature above the processing temperature for embedding the components. In other or further embodiments, the elastomeric layer can be segmented, with alternating translucent, opaque, colored, and colorless transparent materials. Depending on the stiffness of the elastomeric and the selection of the outer layer, the device can be envisioned to have sufficiently high stiffness and stability without the need for further processing, such as backside injection molding.

[0016] The present invention will now be described more fully with reference to the accompanying drawings, in which embodiments of the invention are shown. In the drawings, absolute and relative sizes of systems, components, layers, and regions may be exaggerated for clarity. Embodiments may be described with reference to schematic and / or cross-sectional illustrations of possibly idealized embodiments and intermediate structures of the invention. In the description and drawings, like numbers refer to like elements throughout. Relationship terms and their derivatives should be construed with reference to the orientation shown in the drawings being currently described or discussed. Such relationship terms are for convenience of description and do not require that the system be constructed or operated in a particular orientation, unless otherwise specified.

[0017] FIG. 1A illustrates the fabrication of an electronic device 100, and FIG. 1B shows an electronic device, such as an electronic device resulting from such a method.

[0018] In some embodiments, the method includes providing an electronic substrate 10. For example, as shown, the electronic substrate 10 includes electronic components 11, 12 disposed on and protruding from at least one side 10a of the electronic substrate 10. In some preferred embodiments, the electronic components 11, 12 include at least one light-emitting device 12. For example, the light-emitting device 12 can be configured to emit light 12a, e.g., visible light. In other or further embodiments, a cover substrate 20 can be provided, e.g., the cover substrate 20 can include a graphic pattern 21. For example, the graphic pattern 21 can be formed by one or more layers 20a of material. The material can include an opaque material stack 20m for reflecting or blocking at least a portion of the emitted light or other light within specific regions of the cover substrate 20. Other or additional materials with varying degrees of opacity / transparency can also be used. Preferably, the graphic pattern 21 comprises at least one window 22 for transmitting at least a portion of the emitted light 12 a from each light-emitting device 12 .

[0019] In some embodiments, a thermoplastic layer 30 is disposed between the electronic substrate 10 and the cover substrate 20. Preferably, the thermoplastic layer 30 includes at least some regions having a thermoplastic material 30m for transmitting at least a portion of the emitted light 12a through at least a portion of the thermoplastic layer 30.

[0020] In some embodiments, the electronic substrate 10 and the cover substrate 20 are combined by lamination to form a multilayer laminate 40. Preferably, the electronic substrate 10 is positioned so that the protruding electronic components 11, 12 face the intermediate thermoplastic layer 30. Most preferably, at least the thermoplastic layer 30 is heated to an elevated temperature, e.g., at least above room temperature (300 K). For example, the thermoplastic material 30m is heated to a lamination temperature Tl. This may cause an increase in the plasticity of the thermoplastic material 30m. In some embodiments, the electronic components 11, 12 are pressed into the heated thermoplastic layer 30 by lamination to embed the electronic components 11, 12 within the thermoplastic material 30m.

[0021] Typically, one or more electronic devices may be disposed on an electronic substrate 10, for example, to form a backplate. For example, the electronic substrate 10 may provide electronic functionality for the electronic device 100. For example, the functionality may include one or more of illumination, sensing, actuation, or any other operation or interaction of the device. For example, the electronic components may include electromechanical components, electro-optical components, integrated circuit chips, radiation-emitting components, phototransistors, photovoltaic devices, etc. In a preferred embodiment, for example, as shown, the electronic substrate 10 includes at least one component or device 12 having light-emitting properties, such as a light-emitting diode (LED), for example, to provide backlighting for the electronic device 100. As shown, other (non-light-emitting) devices, such as integrated circuits (chips), may also be present.

[0022] The electronic substrate 10 may include various materials 10m, such as printed electronics, patterned conductors, dielectrics, transistors, and electrical circuits, on one or both sides of the electronic substrate 10a. Additionally, other materials 10m, such as materials that reflect, block, and / or absorb light, may be printed on the electronic substrate 10, for example, to provide optical functionality. In a preferred embodiment, the electronic substrate 10 is formed as a thin film. For example, the electronic substrate 10 is a thin film of polycarbonate (PC) having a relatively thin thickness of less than 1 millimeter, preferably 10 to 1000 microns, more preferably 50 to 500 microns, e.g., 100 microns.

[0023] In some embodiments, the cover substrate 20 described herein can form the front plate of a user interface. For example, the cover substrate 20 can provide graphic and visual functions for the electronic device 100, which can include, for example, optical transmission, light blocking, providing text, patterns, color, or protection. In a preferred embodiment, as shown, the cover substrate 20 includes a graphic pattern 21 formed by one or more layers 20a of opaque material 20m to shield or hide at least a portion of the electronic device 100 from a user and to reflect light within the light guide. For example, the graphic layer is disposed on a (supporting) substrate or film, which can be the same or a different material as the electronic board. In some embodiments, the cover substrate 20 can include a layer or segment layer 20a of graphic ink or functional ink, which can be black or white ink or any other color. In other or further embodiments, the functional pattern can include a cover layer for blocking light. In other or further embodiments, the cover substrate 20 may include a protective layer, such as a scratch-resistant, abrasion-resistant, or UV-protective layer.

[0024] In preferred embodiments, the cover substrate 20 is formed of multiple layers, and visual features, such as patterns or coloring, can be provided through inner or outer layers. In some embodiments, at least a portion of the graphic layer is disposed opposite the thermoplastic layer 30 so that the features remain isolated by at least the thickness of the film and are therefore protected from environmental influences. Therefore, various impacts, friction, chemicals, etc., which can easily damage painted surface features, cannot reach those layers.

[0025] In another or more preferred embodiment, the graphic pattern 21 comprises at least one window 22 for passing at least a portion of the emitted light 12a from each light-emitting device 12. The at least one window 22 is for allowing backlighting to transmit through the cover substrate 20 to the user. In some embodiments, the graphic pattern 21 is configured to block the view of the underlying electronic board 10 and / or to block light emitted from, for example, the light-emitting devices 12 through portions of the cover substrate 20 other than the window 22. For example, the thickness, absorption, and / or (back)reflection of the cover substrate 20 and / or the opaque material 20m is configured to allow less than 90 percent, less than 95 percent, or even less than 99 percent of the emitted light 12a to pass through the opaque regions.

[0026] In a preferred embodiment, the cover substrate 20 is formed of a thin film, for example, a PC thin film having a relatively thin thickness of less than 1 millimeter, preferably 100 to 1000 microns, more preferably 200 to 500 microns, for example 300 microns.

[0027] In some embodiments, one or both of the electronic substrate 10 and / or cover substrate 20 may include a printed material. Printing may be understood as a process of transferring a material, such as ink or other liquid, to a target substrate, e.g., to form a predetermined shape. As described herein, the printed material may include a conductive material capable of forming an electrical connection, e.g., a conductive ink, and / or a colored material for creating graphic elements from the printed material. Printing techniques may include, e.g., screen printing, flexography, and inkjet printing. Of course, other methods of depositing material, such as lamination, lithography, pick-and-place, etc., may also be used to apply layers, circuits, and / or components.

[0028] Typically, thermoplastics, or heat-softening materials, are plastic polymeric materials that become bendable or moldable at elevated temperatures and solidify upon cooling. Thermoplastics differ from thermosetting polymers, which form irreversible chemical bonds during the curing process. Above the glass transition temperature (Tg) and below the melting point, the physical properties of thermoplastics change dramatically without an associated phase transition. Some thermoplastics do not fully crystallize below the glass transition temperature and retain some or all of their amorphous properties. For example, amorphous and semi-amorphous plastics are preferred in some embodiments because they provide high optical clarity.

[0029] In a preferred embodiment, the thermoplastic layer, as described herein, may include an elastomer selected from the family of rigid polyurethanes, such as thermoplastic polyurethane (TPU) or polyvinyl butyral (PVB). For example, the thermoplastic layer 30 has a relatively thin thickness of 1 millimeter or less, preferably 200-1000 microns, more preferably 400-800 microns, e.g., 500 microns, but at least the height of the tallest component embedded within the layer.

[0030] In a preferred embodiment, the electronic substrate 10, cover substrate 20, and thermoplastic layer 30 are processed separately. Each material can be configured according to the functional properties and characteristics of the electronic device 100. In another or more preferred embodiment, for example as shown, the cover substrate 20 and the electronic substrate 10 are later combined into a multi-layer laminate 40 by laminating the thermoplastic layer 30 therebetween to form an overall stack. In some embodiments, the electronic substrate and / or cover substrate 10, 20 can also comprise a thermoplastic material.

[0031] In physics and material science, plasticity generally describes the deformation of a (solid) material that undergoes an irreversible shape change in response to an applied force, as opposed to, for example, elastic deformation. In the context of the present disclosure, the thermoplastic material 30m can be deformed by forcing the electronic components 11, 12 into the thermoplastic layer 30. Increasing the plasticity of the thermoplastic material 30m can make it relatively easy to deform the material so that the electronic components 11, 12 are forced into the thermoplastic layer 30. For example, the plasticity can be increased (i.e., the material becomes more bendable or moldable) by heating the material to a lamination temperature Tl, which is preferably near or above the glass transition temperature of the material.

[0032] Glass transition is generally understood as the gradual and reversible transition of amorphous or semi-crystalline regions in a material from a hard, relatively brittle "glassy" state to a viscous or rubbery state as the temperature is increased. Typically, the glass transition temperature (Tg) of a material can characterize the narrow temperature range over which the glass transition occurs. Depending on the material, the difference in stiffness below and above Tg can be several orders of magnitude. While various definitions of Tg may differ by a few degrees Kelvin, it will be apparent that a material can become significantly more malleable once a critical threshold within the range over which the glass transition occurs is crossed. To disambiguate the relative temperatures used in this disclosure, the glass transition temperature can be defined in terms of viscosity, with Tg being defined as 10 13 Poise or 1012 It is fixed at a value of Pa·s.

[0033] In a preferred embodiment, the lamination temperature Tl is above the glass transition temperature Tg30 of the thermoplastic material 30m and below the glass transition temperatures Tg10, Tg20 of the electronic substrate and / or cover substrate 10, 20. For example, the lamination temperature Tl is at least 1, 2, 3, or 5 degrees Celsius above the glass transition temperature Tg30 of the thermoplastic material 30m and / or at least 1, 2, 3, or 5 degrees Celsius below the glass transition temperatures Tg10 or Tg20 of the electronic substrate and / or cover substrate 10, 20 (which may or may not be the same material). Advantageously, this may allow for the setting of a first processing temperature, i.e., lamination temperature Tl, at which the thermoplastic layer 30 becomes relatively soft, while the electronic substrate and / or cover substrate 10, 20 remains relatively hard. For example, at the first processing temperature, the electronic components 11, 12 may be pressed into the thermoplastic layer 30m, so that the components are at least partially submerged or embedded in the thermoplastic material 30m.

[0034] As will be appreciated, by forcing the electronic components 11, 12 into the thermoplastic layer 30, the electronic components 11, 12 can extrude a portion of the thermoplastic material 30m within that layer, which has been softened by the elevated temperature of the thermoplastic layer 30, so that the electronic components 11, 12 Within 30m of the thermoplastic material It can be sunk and tightly embedded, i.e., surrounded or enveloped in the thermoplastic material 30m, which can, for example, surround and contact the light emitting device 12, thereby forming a suitable connection for guiding the emitted light 12a.

[0035] Preferably, the glass transition temperature of the thermoplastic layer 30 is at least 10 degrees Celsius, preferably 20 degrees Celsius, or at least 30 degrees Celsius or more, lower than the glass transition temperature of the electronic substrate and / or cover substrate 10, 20. The lower the glass transition temperature of the thermoplastic layer 30, e.g., at least compared to the glass transition temperature of the electronic substrate 10, the better the components can be pressed into the thermoplastic layer 30 without affecting the shape of the electronic substrate 10, and / or the less stress can be applied to the electronic components 11, 12. On the other hand, the glass transition temperature of the thermoplastic layer 30 is preferably relatively high, e.g., above 80 degrees Celsius, preferably above 100 degrees Celsius or more, to prevent spontaneous softening during normal use of the device. Another or further important aspect may relate to the stiffness or hardness of the material. For example, it may be preferable to use a substrate or layer having a Shore A hardness of more than 50, more than 80, or even more than 100.

[0036] In some embodiments, the multilayer laminate 40 is formed as a sheet having a relatively thin thickness, e.g., 3 millimeters or less, preferably 0.5 millimeters to 1.5 millimeters, more preferably 800 microns to 1 millimeter, e.g., 900 microns. Preferably, the thickness is at least equal to the thickness of the tallest component. In some embodiments, the multilayer laminate 40 forms the electronic device as an end-user product. In other or further embodiments, the multilayer laminate 40 forms part of another or additional component or device.

[0037] Another or further aspect may be embodied as an electronic device 100, for example, manufactured by the methods described herein or otherwise. For example, as shown, the electronic device 100 may include one or more of the electronic substrate 10, a cover substrate 20, and a thermoplastic layer 30 between the electronic substrate 10 and the cover substrate 20. Other or further layers, such as multiple electronic substrates (not shown), may also be provided. The layers may form a multilayer laminate 40 formed by laminating the electronic substrate 10 and the cover substrate 20 together at an elevated lamination temperature T1 to temporarily increase the plasticity of the thermoplastic material 30m, where the protruding electronic components 11, 12 face the thermoplastic layer 30 between the electronic substrate 10 and the cover substrate 20. Thus, the electronic components 11, 12 are embedded within the thermoplastic material 30m. In some embodiments, the multilayer laminate 40 may have an out-of-plane bent shape, as described below. In other or further embodiments, the electronic substrate 10 is disposed between the thermoplastic material 30m and an injection molded thermoset material 60m.

[0038] FIG. 2A shows a cross-sectional view of the thermoforming of the multi-layer laminate 40, and FIG. 2B shows the multi-layer laminate 40 inside a thermoforming mold 50.

[0039] In some embodiments, for example, as shown, the multilayer laminate 40 is further processed by a shape-transforming process. Preferably, the transformation process includes thermoforming. For example, the transformation process includes imparting a predetermined macroscopic shape to the multilayer laminate 40 to thermoform the stack. Thermoforming is generally understood as a manufacturing process in which a substrate made of a thermoplastic (thermosoftening plastic) material is heated to a bendable forming temperature. Typically, above the material's glass transition temperature and below its melting point, the thermoplastic's physical properties change dramatically without an associated phase transition. The heated substrate can be formed into a specific shape, for example, using a mold, and optionally trimmed to create a usable product. Typically, the substrate, such as a sheet or film, is heated to a relatively high temperature to allow it to stretch into or rest on a mold, and then cooled to its final shape.

[0040] In some embodiments, the electronic substrate 10, cover substrate 20, and thermoplastic layer 30 are laminated to initially form a planar multi-layer laminate 40. Preferably, the planar multi-layer laminate 40 is deformed out-of-plane by a subsequent thermoforming process. Most preferably, the multi-layer laminate 40 is processed in a single thermoforming step into the final three-dimensional form of the electronic device 100. For example, a mold 50 of a specific shape is used to produce the final shape.

[0041] In one embodiment, the multilayer laminate 40 is heated in a thermoforming process to a thermoforming temperature (Tt), such as near or above the glass transition temperature (Tg) of the electronic and / or cover substrates 10, 20 (i.e., also above the Tg of the thermoplastic layer 30), allowing the layers to deform to the shape of the mold 50. The multilayer laminate 40 can then be cooled so that it retains its final shape. Preferably, the thermoplastic layer 30 becomes sufficiently flexible at the thermoforming temperature to relieve (lateral) stresses on the electronic components 11, 12. For example, the multilayer laminate 40 can be deformed along one or more out-of-plane directions having respective radii of curvature R. For example, the radius of curvature R of at least some portions of the thermoformed multilayer laminate 40 can be less than 1 meter, less than 0.5 meters, less than 20 centimeters, less than 10 centimeters, less than 5 centimeters, or even smaller. Other portions may be less curved and / or remain flat, for example with a radius of curvature R of more than 1 meter, more than 5 meters, more than 10 meters. The curvature may also extend in different directions. Advantageously, bending the laminate laterally may increase its stiffness. Of course, the radius of curvature R may be different in different directions to form convex, concave, or even saddle-shaped curvatures.

[0042] Although the figure shows thermoforming with a double mold, a single mold can also be used, for example, with the outer side of the cover substrate 20 on the mold. For example, instead of a metal mold, pressure is applied with (heated) air (80 bar or similar). If a laminate is used, all options are possible. In some embodiments, an opening can be provided in the electronic board 10, for example, at the location of the electronic device. Optionally, a flap can be provided on the inside of the electronic board 10, for example, in contact with the thermoplastic layer 30. In this way, contact can be made from the outside to the inside circuitry. For example, an opening can be maintained in the injection-molded material 60m for the opening in the electronic board 10.

[0043] 3A and 3B illustrate reverse injection molding of a multilayer laminate 40. In some embodiments, the thermoformed portion has relatively high rigidity, e.g., the electronic device 100 maintains its (3D) shape without further processing. In other or further embodiments, the electronic device 100 is reinforced by further processes, such as additional layers or backings. In one embodiment, the multilayer laminate 40 at least partially forms part of an enclosed volume, and the method further includes applying an injection molding process to fill the volume with an injection-molded material 60m to reinforce the multilayer laminate 40. For example, as shown, the injection-molded material 60m comprises a thermosetting material. Advantageously, the thermosetting material may have a relatively high melting temperature so that it can withstand high temperatures during use without deformation. In a preferred embodiment, the electronic substrate 10 is disposed between the electronic components 11, 12 and the injection-molded material 60m. It will be appreciated that the injection molded material 60m does not need to be in direct contact with the electronic components 11, 12, so overheating of the components during manufacture can be avoided.

[0044] In some embodiments, the electronic substrate 10 is disposed between the thermoplastic material 30m and a backing layer comprising a thermosetting material applied by injection molding. In other or further embodiments, the backing layer conforms to the shape of the multilayer laminate 40. For example, as shown in the figure, an injection molded shape 60 forms a surface having the same or similar shape as the thermoformed multilayer laminate 40. It can even be envisioned to use the same mold 50 previously used for the thermoforming process, e.g., positioned at a distance from the electronic substrate 10. Alternatively, the backing layer can have other shapes, e.g., simply filling the rear of the volume formed by the thermoformed multilayer laminate 40.

[0045] 4A and 4B schematically show cross-sectional views of an electronic device 100. For example, the figures show preferred embodiments or variations relating to the electronic substrate 10, cover substrate 20, and thermoplastic layer 30. In some embodiments, the thermoplastic layer 30 comprises or consists essentially of a thermoplastic material 30m. Preferably, at least a portion of the thermoplastic layer 30 has optical properties that allow at least a portion of the emitted light 12a from the electronic substrate 10 to be transmitted through at least a portion of the thermoplastic layer 30 and transmitted to the cover substrate 20. Thus, the emitted light 12a can reach a user. For example, at least a portion of the thermoplastic layer 30 surrounding the light-emitting device 12 is transparent or translucent.

[0046] In other or further embodiments, portions of the thermoplastic material 30m', e.g., including other non-light-emitting components 11, can be less transparent and / or absorbent to the emitted light 12a, thereby reducing the visibility of those other components to a user viewing the electronic device 100, e.g., from the cover substrate 20 side. In preferred embodiments, the thermoplastic layer 30 includes at least two different types of thermoplastic material 30m. In some embodiments, the thermoplastic layer 30 in a first region including the light-emitting devices 12 includes a first type of thermoplastic material 30m that is relatively transparent to the emitted light 12a. In other or further embodiments, the thermoplastic layer 30 in a second region not including the light-emitting devices 12 includes a second type of thermoplastic material 30m' that is relatively opaque to the emitted light 12a, e.g., at least less transparent than the first region. For example, the thermoplastic material 30m' in the second region has an absorption coefficient (e.g., for the emitted light or other visible light) that is at least two times higher than the thermoplastic material 30m in the first region. In a preferred embodiment, such a thermoplastic layer 30 is formed by cutting two or more layers of different thermoplastic materials 30m into complementary patterns. For example, the pattern may include a pattern of relatively transparent thermoplastic material 30m to cover the at least one light-emitting device 12.

[0047] In some embodiments, at least a portion of the relatively opaque thermoplastic material 30m' can be black, i.e., absorb most of the light, for example to shield portions of the electronic components 11 from view. In other or further embodiments, at least a portion of the thermoplastic layer 30 comprises a patch of opaque white thermoplastic material 30m' to reflect the emitted light 12a of the at least one light-emitting device 12 towards the respective window 22. Advantageously, if the relatively opaque thermoplastic material 30m' is white (at least surrounding the first region), this can help reflect the emitted light 12a from the light-emitting device 12 through the relatively transparent thermoplastic material 30m. Alternatively, or in addition to using a reflective thermoplastic material, it can also be envisioned that the volume of the thermoplastic layer 30 comprising the light-emitting device 12 is coated with one or more layers 10w, 20w, 30w of reflective material.

[0048] In some embodiments, for example, as shown in the upper figures, a reflective and / or white layer 20w can be formed between the thermoplastic layer 30 and the cover substrate 20. Optionally, another layer 20b, for example, of a black or other absorbing color, can be disposed between the reflective and / or white layer 20w and the cover substrate 20 and / or the top side of the device. As will be appreciated, the lower white / reflective layer 20w can help reflect the light downward (thereby improving efficiency), while the upper black layer can help absorb light transmitted through the white layer. In other or further embodiments, for example, as shown in the lower figures, an additional layer 10w, 20w of reflective material can be applied, for example, to the electronic substrate 10 and / or as part of the thermoplastic layer 30. For example, a light guide structure can be formed.

[0049] In some embodiments, for example as shown in the figures below, the electronic substrate 10 comprises two or more light emitting devices 12. In other or further embodiments, the cover substrate 20 comprises two or more windows 22, for example, one per light emitting device 12, for transmitting at least a portion of the emitted light 12a from each light emitting device 12. The use of multiple light emitting devices per window or multiple windows per light emitting device can also be envisioned (not shown).

[0050] In preferred embodiments, the light-emitting devices 12 are centered below and at least partially overlap the respective windows 22. For example, the windows are configured to transmit more than 20 percent, more than 30 percent, more than 50 percent, more than 80 percent, more than 90 percent, more than 95 percent, or even more than 99 percent of the emitted light 12a through the window area. In some embodiments, the windows include color filtering portions, e.g., to transmit specific wavelengths of the emitted light 12a. In other or further embodiments, the electronic substrate 10 includes one or more at least partially reflective surfaces or materials 10m that aid in light guiding, e.g., to reflect more than 20 percent, more than 30 percent, more than 50 percent, more than 80 percent, more than 90 percent, more than 95 percent, or even more than 99 percent of the emitted light 12a. For example, the electronic substrate 10 may include white patches.

[0051] In some embodiments, for example as shown, the cover substrate 20 comprises two graphic patterns 21, for example one on the outer side of the cover substrate 20 and the other on the inner side of the cover substrate 20 opposite the thermoplastic layer 30. The graphic patterns may each comprise one or more layers of (graphic) material. In other or further embodiments, for example as shown, the cover substrate 20 comprises one or more layers of white ink 20w and / or black ink 20b.

[0052] In some embodiments, other variations of the electronic substrate 10 are possible, for example, as shown. For example, the electronic substrate 10 includes electrical circuit traces 13. Preferably, the electrical circuit traces 13 are flexible. For example, the circuit traces can be printed, for example, with (flexible) ink. The electronic components 11, 12 can be connected to the electrical circuit traces 13 on at least one side of the electronic substrate 10. In other or further embodiments, for example, as shown, the electronic substrate 10 includes interconnection accesses 14 for electrically accessing the electrical circuit traces 13 from another side of the electronic substrate 10 opposite the side 10a, where the electronic components 11, 12 protrude from the electronic substrate 10 into the thermoplastic material 30m. For example, the interconnection accesses 14 can be used to easily connect the electronic components 11, 12 to additional circuits or controllers or to perform maintenance on embedded circuits. For example, the electrical circuit lines 13 can be accessed by the interconnect access 14 by holes and wires, or by vertical interconnect access VIAs.

[0053] For purposes of clarity and conciseness, features may be described herein as part of the same or separate embodiments; however, it will be appreciated that the scope of the present invention may include embodiments having all or any combination of the described features. Various elements of the embodiments discussed and illustrated provide certain advantages, such as ease of manufacture, robustness, and low cost. Of course, it should be appreciated that any one of the above-described embodiments or processes may be combined with one or more other embodiments or processes to provide further improvements in design and advantages and combinations thereof. It will be appreciated that the present disclosure provides particular advantages for user interface designs incorporating light-emitting devices arranged as backlighting for a graphic pattern on a front cover, and may generally be applied to any application for protecting electronic components between integrated combinations of layers.

[0054] When interpreting the appended claims, it should be understood that the word "comprising" does not exclude the presence of elements or acts other than those listed in a given claim, the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements, and reference signs in a claim do not limit its scope, and that several "means" may be represented by the same or different items or structures or functions performed, and that any disclosed device or part thereof may be combined with one another or divided into further parts unless expressly stated otherwise. When a claim refers to another claim, this may indicate synergistic advantages achieved by a combination of their respective features. However, the mere fact that certain measures are recited in mutually different claims does not mean that a combination of these measures cannot be used to advantage. Thus, embodiments of the present disclosure may encompass all valid combinations of claims, and each claim may, in principle, refer to any preceding claim unless the context clearly excludes otherwise.

Claims

1. A method of manufacturing an electronic device (100), comprising: providing an electronic substrate (10) having electronic components (11, 12) disposed on at least one side (10a) of the electronic substrate (10) and projecting therefrom, wherein the electronic components (11, 12) have at least one light-emitting device (12) for emitting light (12a); providing a cover substrate (20) comprising a graphic pattern (21) formed by one or more layers (20a) of opaque material (20m), wherein the graphic pattern (21) comprises at least one window (22) for transmitting at least a portion of the emitted light (12a) from each light-emitting device (12); providing a thermoplastic layer (30) between the electronic substrate (10) and the cover substrate (20), wherein the thermoplastic layer (30) comprises a thermoplastic material (30m) for transmitting at least a portion of the emitted light (12a) through at least a portion of the thermoplastic layer (30); forming a multilayer laminate (40) by laminating and combining the electronic substrate (10) and the cover substrate (20), wherein the protruding electronic components (11, 12) face the thermoplastic layer (30) between the electronic substrate (10) and the cover substrate (20), wherein at least the thermoplastic layer (30) is heated to a lamination temperature (T1) to increase the plasticity of the thermoplastic material (30m), and the electronic components (11, 12) are pressed into the heated thermoplastic layer (30) by the lamination, and the electronic components (11, 12) push out a portion of the thermoplastic material (30m) in the thermoplastic layer (30), thus sinking and firmly embedding the electronic components (11, 12) in the thermoplastic material (30m); Including, the electronic substrate (10) is placed between the thermoplastic material (30m) and a backing layer comprising a thermosetting material applied by injection molding; The method.

2. 2. The method of claim 1, wherein the lamination temperature (Tl) is above the glass transition temperature (Tg30) of the thermoplastic material (30m) and below the glass transition temperature (Tg10) of the electronic substrate (10) and / or below the glass transition temperature (Tg20) of the cover substrate (20).

3. 3. The method of claim 1 or 2, wherein the electronic substrate (10), cover substrate (20), and thermoplastic layer (30) are laminated to initially form a planar multi-layer laminate (40), which is subsequently deformed out-of-plane by a thermoforming process.

4. 4. The method of claim 1, wherein the multilayer laminate (40) is heated in a thermoforming process to a thermoforming temperature (Tt) above the glass transition temperature (Tg10) of the electronic substrate (10) and above the glass transition temperature (Tg20) of the cover substrate (20).

5. 5. The method according to any one of claims 1 to 4, wherein the multilayer laminate (40) forms part of a closed volume, the method further comprising applying an injection molding process to fill the volume with an injection molding substance (60m) to reinforce the multilayer laminate (40).

6. The method according to any one of claims 1 to 5, wherein the thermoplastic layer (30) comprises patches of opaque white thermoplastic material (30m') for reflecting the emitted light (12a) of the at least one light-emitting device (12) towards the respective window (22).

7. The method according to any one of claims 1 to 6, wherein the volume of the thermoplastic layer (30) comprising the light-emitting device (12) is coated with one or more layers (10w, 20w, 30w) of reflective material.

8. The method according to any one of claims 1 to 7, wherein the cover substrate (20) comprises at least one white layer (20w) and at least one black layer (20b), and the white layer (20w) is disposed between the electronic substrate (10) and the black layer (20b).

9. 9. The method according to claim 1, wherein the electronic board (10) is provided with interconnection accesses (14) for electrically accessing electrical circuit lines (13) connected to the electronic components (11, 12) from another side of the electronic board (10) opposite to the side (10a) where the electronic components (11, 12) protrude from the electronic board (10) into the thermoplastic material (30m).

10. 10. The method of claim 1, wherein the thermoplastic layer (30) comprises at least two different types of thermoplastic materials (30m), wherein the thermoplastic layer (30) in a first region comprising the light-emitting device (12) comprises a first type of thermoplastic material (30m) that is relatively transparent to the emitted light (12a), and the thermoplastic layer (30) in a second region not comprising the light-emitting device (12) comprises a second type of thermoplastic material (30m') that is relatively opaque.

11. 11. The method of any one of claims 1 to 10, wherein the thermoplastic layer (30) is formed by cutting two or more layers of different thermoplastic materials (30m) into complementary patterns, the patterns including a pattern of relatively transparent thermoplastic material (30m) for covering the at least one light emitting device (12).

12. An electronic device (100), comprising: an electronic board (10) comprising electronic components (11, 12) disposed on at least one side (10a) of the electronic board (10) and projecting therefrom, wherein the electronic components (11, 12) comprise at least one light-emitting device (12) for emitting light (12a); a cover substrate (20) comprising a graphic pattern (21) formed by one or more layers (20a) of opaque material (20m), wherein said graphic pattern (21) comprises at least one window (22) for transmitting at least a portion of the emitted light (12a) from each light-emitting device (12); a thermoplastic layer (30) between the electronic substrate (10) and the cover substrate (20), wherein the thermoplastic layer (30) comprises a thermoplastic material (30m) for transmitting at least a portion of the emitted light (12a) through at least a portion of the thermoplastic layer (30); a multilayer laminate (40) formed by laminating and combining the electronic substrate (10) and the cover substrate (20) at an elevated lamination temperature (T1) to temporarily increase the plasticity of the thermoplastic material (30m), wherein the electronic components (11, 12) are pressed into the heated thermoplastic layer (30) by lamination, the electronic components (11, 12) facing the thermoplastic layer (30) between the electronic substrate (10) and the cover substrate (20), and the electronic components (11, 12) are embedded in the thermoplastic material (30m), the electronic components (11, 12) sinking into the thermoplastic material (30m) and displacing at least a portion of the thermoplastic material (30m); It is equipped with The electronic substrate (10) is disposed between the thermoplastic material (30m) and the injection-molded thermosetting material (60m). The electronic device (100).

13. The device of claim 12, wherein the multi-layer stack (40) has an out-of-plane bent shape.

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