METHOD FOR JOINING A THERMOPLASTIC FILM TO A METAL COMPONENT

Abstract

A method for joining a thermoplastic film to a metal component, at least comprising the following method steps: providing the metal component with a joining surface, incorporating microstructures and/or nanostructures into the joining surface of the metal component, arranging the thermoplastic film on the joining surface of the metal component, softening the thermoplastic film by heating to a temperature above the glass transition temperature of the thermoplastic film, pressing the softened thermoplastic film onto the joining surface of the metal component in such a way that part of the softened thermoplastic film penetrates into the microstructures and/or nanostructures in the joining surface of the metal component, and obtaining an interlocking connection between the thermoplastic film and the metal component after the thermoplastic film has cooled.

Claims

1. A method for joining a thermoplastic film to a metal component, the method comprising: providing the metal component with a joining surface; incorporating microstructures and/or nanostructures into the joining surface of the metal component; arranging the thermoplastic film on the joining surface of the metal component; softening the thermoplastic film by heating to a temperature above a glass transition temperature of the thermoplastic film; pressing the softened thermoplastic film onto the joining surface of the metal component such that part of the softened thermoplastic film penetrates into the microstructures and/or nanostructures in the joining surface of the metal component; and obtaining an interlocking connection between the thermoplastic film and the metal component after the thermoplastic film has cooled.

2. The method according to claim 1, wherein undercuts are introduced into the joining surface of the metal component during the incorporation of the microstructures and/or nanostructures.

3. The method according to claim 1, wherein the incorporation of the microstructures and/or nanostructures into the joining surface of the metal component is carried out by an electrochemical process or by a laser material processing method or by a mechanical process.

4. The method according to claim 1, wherein the heating of the thermoplastic film is carried out by laser irradiation or by infrared irradiation or by a convective heat supply or by inductive or contact heating of the metal component.

5. The method according to claim 1, wherein the heated thermoplastic film is pressed onto the joining surface of the metal component by negative pressure and/or by mechanical pressure.

6. The method according to claim 1, wherein during and/or following the pressing of the heated thermoplastic film onto the joining surface of the metal component, the thermoplastic film and/or the metal component are actively cooled.

7. A method for joining a first thermoplastic film to a metal component and a second thermoplastic film to the first thermoplastic film, the method comprising: joining the first film to the component by the method according to claim 1; arranging the second film on the first film; softening the first film and the second film by heating to a temperature above a glass transition temperature of the first and second films; pressing the softened second film onto the softened first film; and obtaining a bonded connection between the second film and the first film after the films have cooled.

8. A light module for a motor vehicle lighting device, the light module comprising: an illuminant; a metal heat sink; and a thermoplastic circuit carrier film, wherein the circuit carrier film has traces for making electrical contact with the illuminant, wherein the circuit carrier film is connected to the heat sink, and wherein the connection is produced by the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0023] FIG. 1a shows a view of a heat sink as a component of a light module of the invention;

[0024] FIG. 1b shows a view of a light module of the invention;

[0025] FIG. 2 is a cross section of FIG. 1b; and

[0026] FIGS. 3a and 3b show connections of the invention as enlarged excerpts from FIG. 2.

DETAILED DESCRIPTION

[0027] FIGS. 1a and 1b show perspective views of components of a light module 6 of the invention, and FIG. 2 shows a corresponding cross-sectional view along section line AA. The main components of light module 6 are heat sink 200 as a metal component 2, circuit carrier film 100 based on thermoplastic film 1, and illuminant 5, the latter being shown only in FIGS. 1b and 2.

[0028] Heat sink 200 is made of an aluminum, magnesium, or copper alloy, for example, and comprises a plurality of cooling fins and a plate disposed thereon for receiving illuminant 5 to be cooled. Joining surface 20 for connection to circuit carrier film 100 lies on this plate. Within the scope of the joining process of the invention, microstructures 21 running linearly parallel to one another have been incorporated into joining surface 20.

[0029] Circuit carrier film 100 has a plurality of metal traces 101 on its upper side for contacting illuminant 5 electrically connected thereto, wherein illuminant 5 comprises further electronic peripherals for control and/or sensors in addition to a light source.

[0030] Circuit carrier film 100 covers the joining surface (20) region provided with microstructures 21. It can be seen in the cross-sectional view of FIG. 2 that the microstructures represent groove-like depressions and, in the course of the joining method of the invention, are filled by part of thermoplastic film 1 which has been pressed in in the softened, thermoplastic state.

[0031] FIGS. 3a and 3b show enlarged detailed views of the image detail B of FIG. 2. wherein FIGS. 3a and 3b are to be understood as embodiments of the connection of circuit carrier film 100 to heat sink 200, said embodiments being alternatives with respect to one another.

[0032] Microstructures 21 incorporated into joining surface 20 of metal component 2 have a peg-shaped cross section with a dome-shaped widening at the end, as a result of which undercuts 22 are formed. The parts of thermoplastic film 1 or 1a that have penetrated microstructures 21 thus form an interlocking connection 3, in the horizontal and vertical directions, with metal component 2. Said connection 3 is temperature resistant until the glass transition temperature of the thermoplastic used is exceeded again.

[0033] In FIG. 3a, circuit carrier film 100 has been joined directly to heat sink 200 in an interlocking connection 3, whereas in the embodiment shown in FIG. 3b, thermoplastic film 1a as an additional joining element builds up interlocking connection 3, and in subsequent method steps, the bonded connection 4 with thermoplastic film 1b of circuit carrier film 100 has been produced. The latter variant serves to protect traces 101 or other components fixedly arranged on the upper side of circuit carrier film 100 from potential damage during the creation of interlocking connection 3.

[0034] The invention is not limited in its implementation to the preferred exemplary embodiment described above. Rather, a number of variants are conceivable which make use of the shown solution even in the case of fundamentally different embodiments. All features and/or advantages arising from the claims, the description, or the drawings, including structural details, spatial arrangements, and method steps, can be essential to the invention both individually and in a wide variety of combinations.

[0035] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.