Method for producing a molded electronic device and molded electronic device

Abstract

A method for producing a molded electronic device (1) comprising the operations: a) providing a printed film (10) and an electronic element (2), the printed film (10) being flexible and comprising a film (12) and at least one printed layer (14, 16), the film (12) having an external face (12a) and an internal face (12b), the at least one printed layer (14, 16) comprising at least one electrically conductive layer (16) arranged on the internal face (12b), the electronic element (2) being electrically connected to the electrically conductive layer (16), then b) injecting and crosslinking polyurethane (20) to form an internal protective layer (24) covering the electronic element (2), the internal protective layer (24) being and having an envelope surface (25), and c) producing by injection a support layer (32, 42) on the internal face (12b), away from the electronic element (2), the support layer (42,42) being configured to stiffen the printed film (10). Figure for abstract: Figure 7,

Description

Title of the invention: Method for producing a molded electronic device and molded electronic device Disclosure area

[0001] The present disclosure relates to a method for producing a molded electronic device, as well as a molded electronic device. In particular, the present disclosure relates to producing an electronic device according to the technique called In-mold Electronic (IME). State of the art

[0002] A method is known comprising the operations:

[0003] providing a printed film and an electronic element, the printed film being flexible and comprising a film and at least one printed layer, the film having an external face and an internal face, the at least one printed layer comprising at least one electrically conductive layer arranged on the internal face, the electronic element being electrically connected to the electrically conductive layer, then

[0004] production by injection of a support layer on the internal face.

[0005] Such a method is generally satisfactory. However, certain electronic elements of the electronic devices thus produced have reliability problems, a short lifespan or generate waste. Disclosure Statement

[0006] To overcome the above-mentioned problems, according to the disclosure, the method for producing a molded electronic device comprises the operations:

[0007] a) providing a printed film and an electronic element, the printed film being flexible and comprising a film and at least one printed layer, the film having an external face and an internal face, the at least one printed layer comprising at least one electrically conductive layer arranged on the internal face, the electronic element being electrically connected to the electrically conductive layer, then

[0008] b) injection and crosslinking of polyurethane to form an internal protective layer covering the electronic element, the internal protective layer having an envelope surface, and

[0009] c) production by injection of a support layer on the internal face, away from the electronic element, the support layer being configured to stiffen the electronic film.

[0010] Thus, during operation b), the electronic element is subjected to relatively mild manufacturing conditions, the polyurethane injection being able to be carried out at a moderate pressure and temperature. In return, the internal protective layer does not offer high impact resistance and the rigidity of the internal protective layer is significantly reduced under high temperature conditions such as those of a vehicle interior exposed to sunlight. However, this function is fulfilled by the support layer, the construction of which does not significantly reduce the reliability of the electronic element since the support layer is away from the electronic element.

[0011] "Flexible" means that an element, in this case the printed film, is made of such a material, and with such dimensions, that the element, taken in isolation, can deform under its own weight when it is placed on two supports arranged at its most distant ends.

[0012] "Rigid" means that an element, in this case the support layer, is made of such a material, and with such dimensions, that the element does not deform under the effect of mechanical stresses applied under normal conditions of use. In particular, the subassembly formed by the printed film and the support layer does not exhibit any perceptible deformation when a force of 5 Newtons is applied to the printed film at the level of the support layer. In other words, the printed film is stiffened by the support layer.

[0013] Such a method makes it possible in particular to advantageously produce an electronic device in which the electronic element is a light source or a screen. The electronic element is for example a diode, an LCD screen, an OLED screen, or a micro-LED matrix. The diode is for example a light-emitting diode (LED). Alternatively, the electronic element is a microcontroller, a capacitor, an LED driver module, a multiplexer or an amplifier.

[0014] Thus, the internal protective layer makes it possible to maintain the electronic element relative to the printed film, while creating diffusion and passage of light through the printed film, from the electronic element to the external face.

[0015] According to another characteristic in accordance with the disclosure, operation b) is preferably carried out prior to operation c).

[0016] Thus, the internal protective layer protects (insulates) the electronic element from the material injected during operation c) by forming a screen between the injected material and the electronic element.

[0017] According to an alternative characteristic in accordance with the disclosure, operation c) is preferably carried out prior to operation b).

[0018] According to another characteristic in accordance with the disclosure, preferably the method further comprises making at least one passage in the printed film, then operation b) comprises making an external protective layer on the external face of the film and a bridge connecting the external protective layer and the internal protective layer by circulating the polyurethane through the passage.

[0019] Thus, during the same injection operation, the electronic element is protected by the inner protective layer and the outer side of the film is protected by the outer protective layer.

[0020] According to an additional characteristic in accordance with the disclosure, preferably operation b) comprises the injection of polyurethane only opposite one of the external face and the internal face, and the circulation of the polyurethane through said passage.

[0021] According to a further additional characteristic in accordance with the disclosure, preferably operation b) comprises the injection of polyurethane only opposite the external face and the circulation of the polyurethane through said passage to produce the internal protective layer.

[0022] According to a complementary or alternative characteristic in accordance with the disclosure, preferably the passage is carried out in a marginal portion of the printed film and the method further comprises an operation e) of removing material at the level of the marginal portion removing the bridge connecting the external protective layer and the internal protective layer, operation e) being subsequent to operations b) and c).

[0023] Thus, the bridge does not alter the aesthetics of the electronic device.

[0024] According to another characteristic in accordance with the disclosure, preferably operation b) is carried out at a temperature below 100 degrees Celsius and operation c) is carried out at a temperature above 200 degrees Celsius.

[0025] Thus, the risk of alteration of the electronic element during step b) is reduced and the risk of degradation of the mechanical resistance of the electronic device in the event of high heat is reduced.

[0026] According to another characteristic in accordance with the disclosure, preferably operation b) is carried out at a pressure lower than 120 bar and operation c) is carried out at a pressure higher than 400 bar.

[0027] Thus, the risk of alteration of the electronic element during step b) is reduced and the manufacturing cost of the electronic device can be reduced while maintaining good perceived quality.

[0028] According to another characteristic in accordance with the disclosure, the internal protective layer is preferably transparent or translucent.

[0029] "Transparent" or "translucent" means that an element, in this case the internal protective layer, has a light transmission rate greater than 5%, for example greater than 50%, in particular equal to 100%. Transparent means an element that does not diffuse light and translucent means an element that diffuses light.

[0030] According to an additional characteristic in accordance with the disclosure, operation c) preferably comprises the following sub-operation:

[0031] cl) production of a transparent layer at least partially covering the layer internal protector.

[0032] Thus, the inner protective layer can be circumscribed to the surroundings of the electronic element and a transparent area can be formed through which light can diffuse around the electronic element comprising not only the inner protective layer, but also the transparent layer.

[0033] According to another characteristic in accordance with the disclosure, operation c) preferably comprises the following sub-operation:

[0034] c2) production of an opaque layer coming into contact with the internal face of the film.

[0035] Thus, the opaque layer stiffens the printed film and prevents light from escaping from the internal side of the electronic device.

[0036] "Opaque" means that an element, in this case the opaque layer, has a light transmission rate of less than 5%, for example 0%.

[0037] According to another characteristic in accordance with the disclosure, operation c) preferably comprises the following sub-operations:

[0038] cl) production of a transparent layer covering at least in part the internal protective layer, then

[0039] c2) production of an opaque layer coming into contact with the internal face of the film and re covering at least partially the transparent layer.

[0040] In various embodiments of the device according to the disclosure, one and / or the other of the following arrangements may optionally be used:

[0041] - the opaque layer is configured to reflect light;

[0042] - operations b) and c) are configured to produce an uncovered portion of the envelope surface;

[0043] - the method further comprises an operation d) during which a reflector of light is arranged opposite the uncovered portion;

[0044] - a light source is arranged opposite the uncovered portion.

[0045] The present disclosure further relates to a molded electronic device comprising:

[0046] - a printed film, the printed film being flexible and comprising a film and at least a printed layer, the film having an external face and an internal face, the at least one printed layer comprising at least one electrically conductive track arranged on the internal face,

[0047] - an electronic element electrically connected to the electrically conductive track,

[0048] - an internal protective layer covering the electronic element, the pro layer internal cover being made of crosslinked polyurethane, and

[0049] - a support layer extending on the internal face, away from the electronic element electronic, the support layer stiffening the printed film.

[0050] According to an additional characteristic, the molded electronic device comprises further preferably an outer protective layer on the outer face of the film, the outer protective layer being made of crosslinked polyurethane.

[0051] According to an additional characteristic, the molded electronic device preferably further comprises a bridge connecting the external protective layer and the internal protective layer, the bridge being made of crosslinked polyurethane.

[0052] According to another characteristic, the internal protective layer is preferably made of transparent crosslinked polyurethane. Brief description of the figures

[0053] Other features and advantages of the present disclosure will become apparent from the following detailed description, with reference to the accompanying drawings in which:

[0054] [Fig. 1] represents a first operation of producing an electronic device molded according to a first method,

[0055] [Fig.2] represents a second operation of production of the electronic device molded according to the first process,

[0056] [Fig.3] represents a third operation of production of the electronic device molded according to the first process,

[0057] [Fig.4] represents the molded electronic device obtained according to the first method,

[0058] [Fig.5] represents a first operation and a second operation of realization of an electronic device molded according to a second method,

[0059] [Fig.6] represents a third operation of production of the electronic device molded according to the second process,

[0060] [Fig.7] represents the molded electronic device obtained according to the second method,

[0061] [Fig.8A], [Fig.8B] and [Fig.8C] represent, according to the arrow marked VIII, in [Fig.7] three variants of the molded electronic device obtained according to the second method. Detailed description of the disclosure

[0062] Figures 1 to 3 illustrate the production of a molded electronic device 1 shown in [Fig.4], according to a first method.

[0063] As illustrated in [Fig.l], a printed film 10, an electronic element 2 and a robust element 4 are placed in a first mold 60. The printed film 10 comprises a film 12, a decorative layer 14 and an electrically conductive layer 16. The film 12 has an external face 12a and an internal face 12b. The decorative layer 14 is optional. In the illustrated embodiment, the decorative layer 14 is arranged on the internal face 12b of the film 12, between the film 12 and the electrically conductive layer 16. Alternatively, the decorative layer 14 could be arranged on the external face 12a of the film 12. The decorative layer 14 is preferably opaque and serves in particular to mask certain elements and / or represent pictograms or the like. The decorative layer 14 is produced by printing a decorative ink on the film 12. The electrically conductive layer 16 is arranged on the inner face 12b. This expression should be understood to mean that the electrically conductive layer 16 is arranged on the inner side of the film 12 (below the film 12 in FIGS. 1 to 4), but the electrically conductive layer 16 is not necessarily arranged directly on the inner face 12b. The electrically conductive layer 16 comprises at least one electrically conductive track, preferably multiple electrically conductive tracks electrically insulated from each other. The electrically conductive layer 16 is preferably produced by printing an electrically conductive ink (for example based on copper or silver) on the film 12.

[0064] The film 10 is flexible and has a thickness preferably between 50 microns and 750 microns.

[0065] The electronic element 2 is arranged on the inner face 12b of the film 12. The electrically conductive layer 16 is arranged between the film 12 and the electronic element 2. The electronic element 2 is electrically connected to the electrically conductive layer 16, preferably to several tracks of the electrically conductive layer 16. The electronic element 2 is fragile in the sense that it has low resistance to temperature and / or pressure. The electronic element 2 may in particular comprise a diode, an LCD screen, an OLED screen or a TFT screen. Like the electronic element 2, the robust element 4 is arranged on the inner face 12b of the film 12. The electrically conductive layer 16 is arranged between the film 12 and the robust element 4. The robust element 4 is electrically connected to the electrically conductive layer 16, preferably to several tracks of the electrically conductive layer 16. The robust element 4 is optional.The robust element 4 is capable of withstanding higher temperature and pressure than the electronic element 2.

[0066] The first mold 60 has a first part 62, a second part 64 and a cavity 66. The decorative layer 14 and the electrically conductive layer 16 are printed on the film 12 to produce the printed film 10. Then, the electronic element 2 and the robust element 4 are connected to the electrically conductive layer 16. Then, the printed film 10, the electronic element 2 and the robust element 4 are placed in the cavity 66 of the first mold 60, the external face 12a of the film 12 being placed in abutment against the first part 62 of the first mold 60. A part of the cavity 66 is left free around the electronic element 2 and polyurethane 20 is injected therein. Preferably, the polyurethane is injected at a temperature between 70 and 100°C and a pressure between 20 and 120 bar. The composition for forming injected polyurethane is well known and includes in particular an isocyanate and a polyol which are reacted.

[0067] The polyurethane is allowed to crosslink. As illustrated in [Fig.2], an internal protective layer 24 covering the electronic element 2 and having an envelope surface 25 (exposed, in other words uncovered) is thus produced on the internal face 12b of the film 12, more precisely on the electrically conductive layer 16.

[0068] The printed film 10, the electronic element 2, the robust element 4 and the internal protective layer 24 are then arranged in a second mold 70. The second mold 70 has a first part 72, a second part 74 and a cavity 76. The external face 12a of the film 12 is placed in abutment against the first part 72 of the second mold 70. A part of the cavity 76 is left free, in particular around the internal protective layer 24 and the robust element 4, a transparent material 30 is injected therein. The transparent material 30 is preferably polycarbonate (PC), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene (ABS), a mixture of polycarbonate (PC) and polymethyl methacrylate (PMMA), polyamide (PA), styrene-methyl methacrylate (SMMA), a cycloolefin copolymer (COC) or styrene acrylonitrile (SAN).Preferably, the transparent material 30 is injected at a temperature between 200 and 300°C and a pressure between 600 and 700 bar.

[0069] As illustrated in [Fig. 3], a transparent layer 32 is thus formed covering the electronic element 2 and the robust element 4. More precisely, the transparent layer 32 extends in contact with the envelope surface 25 of the internal protective layer 24, the internal protective layer 24 being interposed between the electronic element 2 and the transparent layer 32. In the illustrated embodiment, the transparent layer 32 completely covers the envelope surface 25. Furthermore, the transparent layer 32 forms a single element. Alternatively, the transparent layer 32 could comprise two separate elements, one extending around the electronic element 2, the other around the robust element 4. The transparent layer 32 is rigid and temperature resistant (more temperature resistant than the internal protective layer 24).

[0070] The printed film 10, the electronic element 2, the robust element 4, the internal protective layer 24 and the transparent layer 32 are then arranged in a third mold 80. The third mold 80 has a first part 82, a second part 84 and a cavity 86. The external face 12a of the film 12 is placed in abutment against the first part 82 of the third mold 80. A part of the cavity 86 of the third mold 80 is left free and an opaque material 40 is injected therein.

[0071] As illustrated in [Fig. 4], the electronic device 1 is thus produced. The electronic device 1 is for example a vehicle interior device, for example a motor vehicle. The electronic device 1 has an opaque layer 42 formed by the opaque material 40 and covering the entire internal face 12b. However, the transparent layer 32 is interposed between the robust element 4 and the opaque layer 40, while the internal protective layer 24 and the transparent layer 32 are in interposed between the electronic element 2 and the opaque layer 40. In the illustrated embodiment, the opaque layer 42 completely covers the transparent layer 32. Furthermore, the opaque layer 42 forms a single element. The opaque layer 42 is rigid and temperature resistant (more temperature resistant than the internal protective layer 24). The opaque layer 42 is preferably white to reflect light towards the external face 12a of the film 12, in other words towards a user.

[0072] Alternatively, the transparent layer 32 could be omitted.

[0073] The first mold 60, the second mold 70 and the third mold 80 may be constituted by one or two devices whose cavity can be modified, for example by retracting walls or removing elements. In other words, the second mold 70 may be constituted by the first mold in a different configuration and the third mold may be constituted by the first mold 60 or the second mold 70 in a different configuration.

[0074] Figures 5 and 6 illustrate the production, according to a second method, of a molded electronic device 1 shown in Figures 7, 8A, 8B and 8C.

[0075] As illustrated in [Fig.5], the printed film 10, the electronic element 2 and the robust element 4 are placed in a fourth mold 90. The fourth mold 90 has a first part 92, a second part 94 and a cavity 96.

[0076] The decorative layer 14 and the electrically conductive layer 16 are printed on the film 12 to produce the printed film 10. A passage 18 extending through the printed film 10 is produced. The passage 18 can be made before or after the printing of the decorative layer 14 and the electrically conductive layer 16 on the film 12. The electronic element 2 and the robust element 4 are electrically connected to the electrically conductive layer 16. Then, the printed film 10, the electronic element 2 and the robust element 4 are placed in the cavity 96. The external face 12a of the film 12 is placed opposite the first part 92 of the fourth mold 90. The printed film 10 is pressed against the second part 94 of the fourth mold 90, by means of the internal face 12b of the film 12, the decorative layer 14 or the electrically conductive layer 16.Alternatively, the outer face 12a of the film 12 could bear against the first part 92 of the fourth mold 90, so that the printed film 90 would be pinched between the first part 92 of the fourth mold 90 and the second part 94 of the fourth mold 90.

[0077] A first sub-cavity 96a, a second sub-cavity 96b and a third sub-cavity 96c forming part of the cavity 96 are left free. The first sub-cavity 96a extends between the external face 12a of the film 12 and the first part 92 of the fourth mold 90. The second sub-cavity 96b extends between the internal face 12b of the film 12 and the second part 94 of the fourth mold 90, around the electronic element 2. third sub-cavity 96c extends between the internal face 12b of the film 12 and the second part 94 of the fourth mold 90, around the robust element 4.

[0078] Polyurethane 20 is injected into the first sub-cavity 96a from the first part 92 of the fourth mold 90. The polyurethane 20 fills the first sub-cavity 96a by coming into contact with the external face 12a of the film 12. Furthermore, the polyurethane 20 passes through the passage 18 and fills the second sub-cavity 96b by coming into contact with the internal face 12b of the film 12 and the electronic element 2. Alternatively, polyurethane could be injected into the second sub-cavity 96b, from the second part 94 of the fourth mold 90, fill the second sub-cavity 96b by coming into contact with the internal face 12b of the film 12 and the electronic element 2, then pass through the passage 18 and fill the first sub-cavity 96a by coming into contact with the external face 12a of the film 12. 12.

[0079] After crosslinking the polyurethane, as illustrated in [Fig. 6], an outer protective layer 22, an inner protective layer 24 and a bridge 26 are thus produced. The outer protective layer 22 covers the outer face 12a of the film 12. The inner protective layer 24 is arranged on the inner face 12b of the film 12, more precisely on the electrically conductive layer 16. The inner protective layer 24 covers the electronic element 2 and has an envelope surface 25 (exposed, in other words uncovered). The bridge 26 extends through the film 12. The bridge 26 connects the outer protective layer 22 and the inner protective layer 24.

[0080] Furthermore, before, concomitantly or after the filling of the first sub-cavity 96a and the second sub-cavity 96b, the transparent material 30 is injected into the third sub-cavity 96c.

[0081] As illustrated in [Fig.6], a transparent layer 32 is thus produced on the internal face 12b of the film 12, more precisely on the electrically conductive layer 16 and covers the robust element 4.

[0082] The printed film 10, the electronic element 2, the robust element 4, the outer protective layer 22, the inner protective layer 24, the bridge 26 and the transparent layer 32 are then arranged in a fifth mold 100. The fifth mold 100 has a first part 102, a second part 104 and a cavity 106. The outer protective layer 22 is placed in abutment against the first part 102 of the fifth mold 100. Furthermore, in the illustrated embodiment, the inner protective layer 24 is placed in abutment against the second part 104 of the fifth mold 100. A part of the cavity 106 is left free and the opaque material 40 is injected therein.

[0083] As illustrated in [Fig.7], the electronic device 1 is thus produced having an opaque layer 42 formed by the opaque material 40. The opaque layer 42 covers the transparent layer 32. Furthermore, the opaque layer 42 covers the entire internal face 12b which is not covered by the inner protective layer 24. However, the transparent layer 32 is interposed between the robust element 4 and the opaque layer 40. The opaque layer 42 comes into contact with a peripheral portion of the envelope surface 25, but is away from an uncovered portion 28 of the envelope surface 25. The opaque layer 42 is rigid and temperature resistant (more temperature resistant than the inner protective layer 24).

[0084] The materials and injection conditions of the polyurethane 20, the transparent material 30 and the opaque material 40 have the characteristics mentioned above in relation to the first method.

[0085] As illustrated in [Fig.7], a light source 50 and a light reflector 52 are then arranged opposite the uncovered portion 28.

[0086] As illustrated in [Fig.8A], the bridge 26 has a cylindrical shape with a circular section.

[0087] According to another variant illustrated in [Fig.8B], the bridge 26 is constituted by a plurality of cylinders of circular section, 9 are illustrated.

[0088] According to a variant illustrated in [Fig.8C], the bridge 26 is made up of a plurality of cylinders whose section corresponds to letters (or more generally a pictogram).

[0089] Of course, the disclosure is in no way limited to the embodiment(s) described for illustrative, non-limiting purposes. Thus, according to the second method, the transparent layer 32 and the opaque layer 42 could be produced before the internal protective layer 24, the external protective layer 22 and the bridge 26.

[0090] According to another variant, the passage 18 could be made in a marginal portion (at the edge) of the printed film 10. After demolding, this marginal portion would be removed by removing material (in particular machining), in particular by milling, so that the finished electronic device would be devoid of the bridge connecting the external protective layer 22 and the internal protective layer 24. Thus, the external protective layer 22 and the internal protective layer 24 would be made during the same injection operation, but would be separate on the finished electronic device.

Claims

Claims

1. A method for producing a molded electronic device (1) comprising the operations of: a) providing a printed film (10) and an electronic element (2), the printed film (10) being flexible and comprising a film (12) and at least one printed layer (14, 16), the film (12) having an outer face (12a) and an inner face (12b), the at least one printed layer (14, 16) comprising at least one electrically conductive layer (16) arranged on the inner face (12b), the electronic element (2) being electrically connected to the electrically conductive layer (16), producing at least one passage (18) in the printed film (10),then b) injection and crosslinking of polyurethane (20) to form an internal protective layer (24) covering the electronic element (2) and production of an external protective layer (22) on the external face (12a) of the film (12) and of a bridge (26) connecting the external protective layer (22) and the internal protective layer (24) by circulating the polyurethane (20) through the passage (18), the internal protective layer (24) having an envelope surface (25), and c) production by injection of a support layer (32, 42) on the internal face (12b), away from the electronic element (2), the support layer (42, 42) being configured to stiffen the printed film (10).,

2. Method according to claim 1 in which operation b) is carried out prior to operation c).

3. Method according to claim 1 in which operation c) is carried out prior to operation b).

4. A method according to any one of the preceding claims wherein operation b) comprises injecting polyurethane (20) only opposite one of the external face (12a) and the internal face and circulating the polyurethane (20) through said passage (18).

5. Method according to any one of the preceding claims in which: the passage (18) is made in a marginal portion of the printed film (10), and the method further comprises an operation e) of removing material at the marginal portion removing the bridge (26) connecting the external protective layer (22) and the internal protective layer (24), operation e) being subsequent to operations b) and c).

6. A method according to any preceding claim wherein step b) is carried out at a temperature below 100 degrees Celsius and step c) is carried out at a temperature above 200 degrees Celsius.

7. A method according to any one of the preceding claims wherein step b) is carried out at a pressure below 120 bar and step c) is carried out at a pressure above 400 bar.

8. A method according to any preceding claim wherein the electronic element (2) is a diode, an LCD screen, an OLED screen, a micro-LED matrix, a microcontroller, a capacitor, an LED driver module, a multiplexer or an amplifier.

9. A molded electronic device (1) comprising: - a printed film (10), the printed film (10) being flexible and comprising a film (12) and at least one printed layer (14, 16), the film (12) having an outer face (12a) and an inner face (12b), the at least one printed layer comprising at least one electrically conductive layer (16) disposed on the inner face (12b), - an electronic element (2) electrically connected to the electrically conductive layer (16), - an inner protective layer (24) covering the electronic element (2), the inner protective layer (24) being made of crosslinked polyurethane, - an outer protective layer (22) on the outer face (12a) of the film (12), the outer protective layer (22) being made of crosslinked polyurethane, - a bridge (26) connecting the outer protective layer (22) and the inner protective layer (24), the bridge being made of crosslinked polyurethane, and - a support layer (32, 42) extending on the internal face (12b),away from the electronic element (2), the support layer (32, 42) stiffening the printed film (10).,

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