Electronically functional multilayer structure

Abstract

An electronically functional multilayer structure is described comprising a first film (1), on which first electrical and / or electronic components (2) are arranged on a first film surface, and comprising a second film (3), on which second electrical and / or electronic components (4) are arranged on a first film surface. The two films (1, 3) are arranged on top of one another in such a way that their sides with the respective first film surfaces face one another, wherein a gap (5) is present between the two films (1, 3) in the region of the first and second electrical and / or electronic components (2, 4).

Description

[0001] The invention relates to an electronically functional multilayer structure comprising a first film on which first electrical and / or electronic components are arranged on a first film surface, and a second film on which second electrical and / or electronic components are arranged on a first film surface, wherein the two films are arranged on top of one another in such a way that their sides with the respective first film surfaces face one another.

[0002] Such an electronically functional multilayer structure is known from US 11,416,081 B1. This comprises a flexible, 3D-formable substrate film having a first surface facing the interior parts of the structure and an opposite second surface facing an environment of the structure and a user therein, wherein the first and second surfaces and the remaining material of the substrate film therebetween locally define a three-dimensional protrusion extending from a plane of the surrounding substrate film material and formed from locally stretched and formed material of the substrate film and forming sidewalls through which a touch is detectable.The circuit provided on the substrate film comprises a number of conductive traces, electrodes and / or components for detecting touches on two or more of the plurality of sidewalls and at least one filler layer on the substrate film to at least partially embed the circuit.

[0003] DE 39 35 792 A1 relates to a housing-enclosed electronic circuit which is arranged on a substrate which is formed, at least in part, by a sintered ceramic foil.

[0004] An injection-molded layer is arranged between the two films, which at least partially surrounds the first electrical and / or electronic components on the first film. As a result, these components are exposed to increased stress during the injection-molding process.

[0005] Such electronically functional multilayer structures can be advantageously used for control elements in vehicles. The installation space for structures with illuminated control elements in the automotive sector (especially in the roof area) is becoming increasingly smaller. Conventional concepts with conventional PCBs and LEDs, including the required light wells for the light emitted by the LEDs, are becoming increasingly difficult to integrate into currently available installation spaces in a vehicle because they require too much installation space.

[0006] However, there is a higher risk of failure rates because the LEDs and circuit traces are directly exposed to the injection molding pressure. If individual LEDs fail, the entire component must be disposed of.

[0007] It is the object of the invention to provide a less sensitive multilayer structure.

[0008] The object is achieved by an electronically functional multi-layer structure with a first film, on which first electrical and / or electronic components are arranged on a first film surface, with a second film, on which second electrical and / or electronic components are arranged on a first film surface, wherein the two films are arranged on top of one another in such a way that their sides with the respective first film surfaces face one another, wherein there is an air gap between the two films in the region of the first and second electrical and / or electronic components.

[0009] The second film surface of the first film can be provided with a first injection-molded layer that is laminated, glued or produced by similar joining or bonding processes.

[0010] The multi-layer structure is realized using an overmolded, laminated, glued, or foamed film construction with a haptic surface and integrated LEDs and touch functions. The LEDs are glued to a film, and the conductor tracks are printed on it. This LED film or flex PCB can optionally be overmolded, laminated, glued, or foamed from below, whereby the LEDs and conductor tracks are advantageously not exposed to injection pressure. The touch surfaces are printed on another film or one of the existing films (depending on the material selection and film thickness), which can be a cover or decorative film, i.e., can have printed symbols, with the decoration facing an environment in which a user can operate the haptic surface. The printed symbols can be printed on the top or bottom, depending on preference: visible without power or not - or function: safety-relevant or not.

[0011] The first electrical and / or electronic components can thus be formed at least with conductor tracks and optically radiating components, while the second electrical and / or electronic components can be formed at least with conductor tracks and touch- or contact-sensitive components.

[0012] On the second foil surface of the second foil, a third foil is arranged, the surface of which facing away from the second foil is provided with printed symbols.

[0013] A second injection-molded layer (laminated, glued or similar joining or bonding processes) is arranged between the second and third films.

[0014] The area between the second touch foil and the third decorative foil can be filled using 2K injection molding (multi-component lamination, bonding, or similar joining or bonding processes). Here, too, the conductive tracks are not subjected to injection pressure because they are applied to the exterior of the component. The two injection-molded elements, formed by the first foil with an optional first injection-molded layer, or the second foil with a second injection-molded layer and the third (decorative) foil, are then positively and / or force-fitted to each other at their edges or at any other possible position, resulting in a single, very flat component.

[0015] Advantageously, when forming the multilayer structure, the second film and—if present—the second injection-molded layer have openings filled with optically transparent material in the area of ​​the LEDs arranged on the first film for the light from the LEDs. This allows the light from the LEDs on the first film to pass through the decorative film. The use of simple, high-quality optics is possible using lenses, diffusers, etc.

[0016] On the first injection-molded layer and / or the second injection-molded layer, domes or ridges can be arranged that extend into the air gap between the two films to ensure sufficient mechanical strength and dimensional stability. These ridges or domes can also serve to prevent stray light between the various LEDs.

[0017] The first injection-molded layer and the second injection-molded layer can have a connection at their edge regions, in particular in the form of rivets formed with one of the injection-molded layers.

[0018] Due to the measures according to the invention, the entire multi-layer structure can have a maximum thickness of a few millimeters.

[0019] By printing conductor tracks and glued LEDs onto one film, as well as printed touch surfaces onto another film, and embedding the films by back-molding, lamination, gluing, or foaming, it is possible to create a very flat design of A-surfaces and integrate all lighting and touch functions into a single component.

[0020] Due to the back-side injection molding process (or laminated, glued or similar joining or connecting processes), the circuit tracks and LEDs are not subjected to injection pressure, which greatly reduces the risk and resulting cost of failure rates.

[0021] Failure rates can be further reduced because, in the case of defective LEDs, the entire overmolded, laminated, bonded, or foamed component does not need to be disposed of if testing can be performed before the two component halves are joined, and subsequent production steps do not significantly influence the OK and NOK status. The A-surface and an LED functional component can be produced and tested separately, which can reduce failure rates for defective components.

[0022] The invention is described in more detail below using an exemplary embodiment with the aid of a figure. Fig. 1 a cross-section through a multilayer structure with LEDs and touch-sensitive elements.

[0023] In the Fig. 1 shows a first film 1 onto which electrical and / or electronic components 2 in the form of conductor tracks and at least LEDs as electronic components are printed or glued. This first film 1 is provided with a first injection-molded layer 6 on its surface facing away from the surface provided with the electrical and / or electronic components 2. By applying this first injection-molded layer 6 to this second film surface, the electrical and / or electronic components 2 are not exposed to the injection-molding pressure. Nevertheless, the film 1 has sufficient stability.

[0024] Also shown is a second film 3, on which at least conductor tracks and touch-sensitive areas are applied as electrical and / or electronic components 4, particularly in the area beneath a second sublayer 8b. This second film 3 can already be provided with printed symbols and haptically recognizable printed areas on its surface facing away from the surface provided with the electrical and / or electronic components 4, thus acting as a decorative film.

[0025] In the exemplary embodiment, however, a third foil 7 is provided, which takes over this decorative function. It can be directly connected to the second foil 3, but in the exemplary embodiment of the Fig. 1 is connected to the second film 3 via a second injection-molded layer 8a, 8b.

[0026] The second injection-molded layer 8a, 8b is formed with a first partial layer 8a, which forms optically transmissive areas for the light from the LEDs on the first film 1. This first partial layer 8a is surrounded by a second partial layer 8b, which supports the entire second injection-molded layer.

[0027] The LEDs can also be placed in an air gap between the second foil 3 and the first sublayer 8a if the second sublayer 8b has significantly thinner walls than the first sublayer 8a. This further results in a flatter design.

[0028] The first injection-molded layer 6 has domes or ridges 11 that extend through the first film 1 and into the air gap 5. Similarly, the second injection-molded layer 8a, 8b has domes or ridges 10 that extend through the second film 3 and into the air gap 5. These domes or ridges 10, 11 support the entire multilayer structure and provide it with dimensional stability. Furthermore, these domes or ridges 10, 11 can prevent stray light between the LEDs.

[0029] The two partial structures consisting of the first film 1 and the first injection-molded layer 6 or the second film 3, the second injection-molded layer 8a, 8b and the third film 7 can be manufactured and tested separately.

[0030] They are then joined together to form the multilayer structure with their surfaces provided with the electrical and / or electronic components 2, 4 facing each other. For this purpose, as shown in the Fig.1, a hot-rivet connection 9 is used, which is connected to the laterally extended second partial injection-molded layer 8c through an edge region of the first injection-molded layer 6. The third film 7 can also be applied over the sides of the multi-layer structure to form a visually appealing surface facing a user.

Claims

[1] Electronically functional multilayer structure with a first film (1) on which first electrical and / or electronic components (2) are arranged on a first film surface, with a second film (3) on which second electrical and / or electronic components (4) are arranged on a first film surface, wherein the two films (1, 3) are arranged on top of one another in such a way that their sides with the respective first film surfaces face each other, wherein there is a gap (5) between the two films (1, 3) in the region of the first and second electrical and / or electronic components (2, 4). characterized by , that a third film (7) is arranged on the second film surface of the second film (3), the surface of which film facing away from the second film (3) is provided with printed symbols, a second injection-molded layer (8a, 8b) being arranged between the second (3) and the third film (7). [2] Electronically functional multilayer structure according to claim 1, characterized by that the gap (5) is filled with a gas. [3] Electronically functional multilayer structure according to claim 1, characterized by that there is a vacuum in the gap (5). [4] Electronically functional multilayer structure according to one of the preceding claims, characterized by that the first electrical and / or electronic components (2) are formed at least with conductor tracks and optically radiating components. [5] Electronically functional multilayer structure according to one of the preceding claims, characterized bythat the second electrical and / or electronic components (4) are formed at least with conductor tracks and touch- or contact-sensitive components. [6] Electronically functional multilayer structure according to one of the preceding claims, characterized by that the second film surface of the first film (1) is provided with a first injection-molded layer (6). [7] Electronically functional multilayer structure according to one of the preceding claims, characterized by that the second foil surface of the second foil (3) is provided with printed symbols. [8] Electronically functional multilayer structure according to one of the preceding claims, characterized by that the second film (3) and the second injection-molded layer (8a) have or have openings filled with translucent material for the light of the LEDs in the region of LEDs arranged on the first film (1). [9] Electronically functional multilayer structure according to one of claims 6 to 8, characterized by that domes (11) projecting into the gap (5) are arranged on the first injection-molded layer (6). [10] Electronically functional multilayer structure according to one of the preceding claims, characterized by that domes (10) projecting into the gap (5) are arranged on the second injection-molded layer (8a, 8b). [11] Electronically functional multilayer structure according to one of claims 6 to 9, characterized by that the first injection-molded layer (6) and the second injection-molded layer (8a, 8b) have a connection (9) at their edge regions (8c).

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