GB2627959A - Electronic device for a vehicle - Google Patents

Abstract

An electronic device with a plastic cover for a vehicle, such as for dashboard instruments, displays or HUDs. A plastic heat sink 2 is integrally connected to a cover 1. The heatsink (5) is thermally connected to an electronic component (3) which may be at a first portion (4) opposite a second portion (5) that may have fins (See figs 1 & 2). The fins are arranged to face outside of the cover with the heatsink forming part of the cover, preferably by fitting through a hole in the cover. The plastic heat sink comprises a thermally conductive filler throughout and an electrically conductive filler which may be located throughout or only in a first portion (4). A portion of the plastic cover (7 figure 2) may also be electrically conductive and may comprise a net or lattice. The electrically conductive portions can help shield for electrical interference in or out of the device such as for meeting EMC requirements.

Description

Description

Electronic device for a vehicle The present invention relates to an electronic device with a plastic cover for a vehicle. Furthermore, the present invention relates to a method for manufacturing a plastic cover of such an electronic device, and to a vehicle comprising such an electronic device.

From the state of the art such electronic devices, for example, instrument clusters, displays and head-up-displays (HUDs) are known. Electronic components arranged in an interior of such an electronic device, for example, computer chips, processors, RAM modules, graphics controllers, automotive controllers, light sources and/or backlights generate heat that must be dissipated outside the electronic devices or rather to an outside or exterior of a cover or housing of the electronic device to protect the individual electronic components and the entire electronic device from overheating and destruction. The cover or housing delimits the electronic device to an outside environment of the electronic device.

To dissipate the heat from an electronic component, it is known to use a cover for the electronic device made of die casting, of a metal alloy, e.g., of a magnesium or aluminum alloy. The heat is transferred from the electronic component to the die casting by thermal coupling, e.g., by a heat-conducting paste and/or a heat-conducting tape. One disadvantage of a die-cast cover or a die-cast housing is that die-cast material has high cost and weight.

In order to reduce the weight and costs of electronic devices, it is known to use a cover made of a standard plastic, for example, acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polypropylene (PP), and/or polyamide (PA), etc. When a cover made of a standard plastic is used, the heat from the electronic components is known to be reduced by natural convection through openings or vents in the plastic cover.

It is also already known from the prior art to increase the thermal conductivity of covers and/or housings which comprise a standard plastic by means of thermally conductive fillers. For example, an electronic device for a motor vehicle is known from DE102014004179A1, in which a plastic cover comprises a thermally conductive filler and in which the cover can consist of different material areas. It is also known from DE102014004179A1 that the plastic cover can be manufactured in an injection molding process with different material areas.

A Problem of such electronic devices with plastic covers is that the plastic covers do not fulfill electromagnetic compatibility (EMC) requirements since the used plastic does not have electrically conductive properties. However, a certain level of EMC is essential to prevent electronic devices or their electronic components from interfering with each other due to unwanted electrical or electromagnetic effects. Another problem with such plastic covers is that openings and vents in the cover lead to condensation and electromigration. Additionally, openings and vents can further compromise electromagnetic compatibility (EMC) by degrading electromagnetic shielding.

It is therefore an object of the present invention to simplify the electromagnetic compatibility of electronic devices with a plastic cover.

This object is achieved by an electronic device for a vehicle according to claim 1, a method for manufacturing a plastic cover of such an electronic device of claim 7 and a vehicle comprising such an electronic device of claim 8. The dependent claims provide provisions of the invention.

According to a first aspect of the present invention, an electronic device comprises at least one plastic heat sink. The plastic heat sink is integrally connected to the plastic cover, thermally connectable to an electronic component and configured to remove heat from the electronic component and to dissipate heat from the electronic component to the environment outside the electronic device. The plastic cover may surround or partially surround the electronic component, which is arranged inside, i.e., arranged in an interior, of the electronic device. In accordance with the invention, plastic cover means that the cover mainly consists of a standard plastic as mentioned above. Furthermore, in accordance with the invention, plastic heat sink means that the heat sink mainly consists of a standard plastic, preferably the same as the plastic cover, but additionally comprises a thermally conductive filler which is contained in the plastic of the heat sink, and additionally comprises an electrically conductive filler which is contained in the plastic of the heat sink. Hence, the basis material of the heat sink is a standard plastic as described above with a certain filler material to enhance the thermal conductivity and electrical conductivity. It is particularly advantageous if the filler used to increase electrical conductivity leads to an electrical conductivity of 1 to 1000 (ohm m)-1 and the filler used to increase thermal conductivity leads to a thermal conductivity of 1 to 40 W/(m*K).

It is further clear that the electronic device may comprise two or more heat sinks, depending on an area or the number of electronic components from which heat needs to be dissipated. If the electronic device comprises at least two heat sinks which comprises thermally conductive and electrically conductive filler, the plastic cover can be manufactured very cost efficient when compared to a cover with die cast heat sinks. If the plastic cover of the electronic device does not comprise openings or vents, the EMC requirements can easier be met.

If only a partial section of the at least one plastic heat sink, i.e., not the whole heat sink, comprises an electrically conductive filler, the section with electrically conductive filler for the heat sink can be adapted to the dimensions of the electronic component in a particularly simple way, furthermore material can be saved and thus the costs be reduced. In this way, specific sections of the heat sink can be provided with specific properties. For example, a first partial section of the heat sink can comprise a thermally conductive filler and additionally an electrically conductive filler, and a second partial section of the heat sink can comprise a thermally conductive filler only without an additional electrically conductive filler or with a filler with electrically isolating properties. Exemplarily, only a single layer of the plastic heat sink may additional to its thermally conductance also comprise the property of electrically conductance. It is clear that the entire heat sink comprises a thermally conductive filler, i.e., the standard plastic of the whole heat sink comprises a respective additional filler, to provide enough heat dissipation from an electronic component of the electronic device while only a certain partial section of the heat sink, e.g., a single layer in the heat sink, may additionally comprise an electrically conductive filler.

If the electrically conductive filler is configured as a net structure or a lattice structure in and/or on the at least one heat sink, material used for the electrically conductivity can be saved but the requirements for EMC still be met. The mesh size of the net or lattice structure can be adapted due to the wavelength which is expected for incoming and/or outgoing electromagnetic radiation and which may disturb the electronic device or other devices in the environment.

If the electrically conductive filler, which is installed in and/or on the at least one heat sink, occupies an area that covers a surface of the electronic component, the requirements for EMC can particularly well met.

If the at least one plastic heat sink is configured such that it extends at least partially around the electronic component in the interior of the electronic device, the protection of an electronic component inside the electronic device from electromagnetic interference can be enhanced. For example, a partial section of the heat sink, which comprises electrically conductive filler, could overlap the electronic component at its extension, e.g., the heat sink can be formed or partially be formed as a kind of a bell extending over the side edges of the electronic component. If additionally the plastic cover comprises an electrically conductive filler, sections of the plastic cover of the electronic device can be selected to enlarge an area which needs to be protected from a penetration of electromagnetic radiation. Thus, the requirements for EMC can be improved and particularly critical areas of the electronic device can be protected from a penetration of electromagnetic radiation. For example, a net or lattice structure of an electrically conductive filler can be introduced in the cover. In addition, parts of the plastic cover can thus be used as electrical connection to a ground potential, similarly to a wire or a conductive path. It is clear that the heat is dissipated from an electronic component via a heat sink and the plastic cover itself does not comprise a thermally conductive filler for heat dissipation.

If the at least one plastic heat sink comprises cooling fins, improved heat dissipation can be made possible by the fin structure. If the heat sink is arranged in the plastic cover such that the extension of the cooling fins does not exceed the extension of the cover in the same direction as the extension of the cooling fins, the cover can be kept particularly flat.

According to a second aspect of the invention, in a method for manufacturing a plastic cover for an electronic device, the plastic cover together with at least one plastic heat sink is manufactured in an injection molding process such that the at least one heat sink comprises a thermally conductive filler which is contained in the plastic of the heat sink and additionally an electrically conductive filler which is contained in the plastic of the heat sink. Alternatively, a 3D printing process can be used for manufacturing such a plastic cover. It is clear that the at least one heat sink and the cover are manufacture such that the heat sink is integrally connected to the cover and the heat sink is thermally connectable to an electronic component which is installed inside the electronic device. For example, in a multi-component injection molding process with one shot, a basis layer of a heat sink with a net or lattice structure could be made of a standard plastic with electrically conducting and thermally conducting filler. In a following shot, the rest of the heat sink, e.g., the cooling fins, which consists of a standard plastic with thermally conducting filler only, could be molded onto the net or lattice structure. The net or lattice structure can also, for example, be filled up with a plastic with enhanced thermally conducting properties, i.e., a standard plastic with thermally conductive filler, to obtain a flat section, that is connectable to the electronic component. The remainder of the plastic cover could then be manufactured in another following shot using a standard plastic material only. Alternatively, the manufacturing process described in the before mentioned example can also be carried out by using a 3D printing process.

According to a third aspect of the invention, a plastic cover which is manufactured according to the method as described with the second aspect of the invention is used as a cover for an instrument cluster, a display, or a head-up-display of a vehicle.

According to a fourth aspect of the invention, a vehicle comprises an electronic 5 device as described above.

It goes without saying that all the above-mentioned features and advantages relating to the describe electronic device can also be related to the described method and/or the described use. Preferably, the described electronic device and/or plastic cover is used in a vehicle. The vehicle may be, for example, a passenger car or a commercial vehicle.

Further features of the present invention will become apparent from the following description and the appended claims in conjunction with the figures.

Figures Fig. 1 shows a sketch of a first embodiment of an electronic device according to the invention, Fig. 2 shows a sketch of a second embodiment of an electronic device according to the invention, Fig. 3a shows a sketch of an embodiment of a plastic cover with integrally connected heat sink according to the invention, Fig. 3b shows a sectional view of Fig. 3a, Fig. 3c shows an exploded view of Fig. 3a, Fig. 4a shows a sketch of a further embodiment of a plastic cover with integrally connected heat sinks according to the invention, Fig. 4b shows a sectional view of Fig. 4a, and Fig. 4c shows an exploded view of Fig. 4a.

Detailed description

For a better understanding of the principles of the present invention, embodiments of the invention will be explained in more detail below with reference to the figures. Like reference numerals are used in the figures for the same or equivalent elements and are not necessarily described again for each figure. It is to be understood that the invention is not limited to the illustrated embodiments and that the features described may also be combined or modified without departing from the scope of the invention as defined in the appended claims.

Fig. 1 shows a sketch of a first embodiment of an electronic device 10 for a vehicle according to the invention. The electronic device comprises a plastic cover 1, an electronic component 3 installed on a printed circuit board 6 and a heat sink 2. The plastic cover 1 delimits the electronic device 10 to an outside environment of the electronic device 10. The electronic component 3 is arranged in the interior of the electronic device 10 behind the plastic cover 1 and produces heat which needs to be dissipated outside the electronic device 10. The electronic device 10, therefore, comprises the heat sink 2 that is integrally connected to the cover 1, thermally connected to the electronic component 3, e.g., via a heat-conducting paste and/or a heat-conducting tape, and configured to remove heat from the electronic component 3 and to dissipate the heat to the environment outside the electronic device 10. The heat sink 2 is adapted slightly inwards from the outer surface of the cover 1, so that the outer edge of the heat sink 2 and the outer surface of the cover 1 are approximately in a plane. This allows a flat design of the cover 1 to be achieved. The heat sink 2 consists of two partial sections, a first partial section 4 which comprises a thermally conductive filler and additionally an electrically conductive filler, and a second partial section 5 which is mainly formed as cooling fins and which comprises only a thermally conductive filler without special electrically conductive properties. The electrically conductive filler used for the heat sink has an electrical conductivity between 1 (ohm *m)-1 to 1000 (ohm *m)-1. The first partial section 4 of the heat sink 2 is configured such that it extends partially around the electronic component 3 in the interior of the electronic device 10. The electronic device 10 is preferably an instrument cluster, a display, or a head-up-display of a vehicle. The plastic cover 1 of the electronic device 10 together with the heat sink 2 is manufactured in an injection molding process or a 3D print process.

Fig. 2 shows a sketch of a second embodiment of an electronic device 10 for a vehicle according to the invention. The heat sink 2 shown in Fig. 2 differs from that one shown in Fig1. in that the electrically conductive filler is configured as a net structure or a lattice structure in the heat sink 2, i.e., the first layer 4. The width of the heat sink 2 in Fig. 2 is the same as the width of the electronic component 3 in Fig. 2. Or in other words, the side edges of the heat sink 2 is flush with the side edges of the electronic component 5 in Fig. 2. Furthermore, in Fig. 2, a cover section 7 of the plastic cover 1 additionally comprises an electrically conductive filler. The electrically conductive filler forms a net or lattice structure within the cover section 7. So to speak, the net or lattice structure in the cover section 7 is molded within or coated with standard plastic for the remaining plastic cover 1 using an injection molding process or a 3D print process.

The figures 3a, 3b and 3c show sketches of an embodiment of a plastic cover 1 with integrally connected heat sink 2 according to the invention. Fig. 3a shows a front view of the plastic cover 1, Fig. 3b shows a sectional view through the dotted lines A-A of Fig. 3a, and Fig. 3c shows an exploded view of Figure 3a. The plastic cover 1 delimits an electronic device to an environment outside of the electronic device. The cover completely consists of a standard plastic, e.g., acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polypropylene (PP), and/or polyamide (PA). The heat sink 2 in the figures 3a, 3b and 3c comprises cooling fins and completely comprises a thermally conducting and an electrically conducting filler. Thus, the original thermal conductivity and electrical conductivity of the material of the standard plastic used for the heat sink 2 is increased. This allows to selectively dissipate heat from an electronic component in the interior of an electronic device to an outside of the electronic device and additionally selectively protect the electronic device or rather electronic components from incoming and outgoing electromagnetic radiation.

The figures 4a, 4b and 4c show sketches of another embodiment of a plastic cover 1 with integrally connected heat sinks 2, N according to the invention. Fig. 4a shows a front view of the plastic cover 1, Fig. 4b shows a sectional view through the dotted lines C-C of Fig. 4a, and Fig. 4c shows an exploded view of Figure 4. The embodiment shown in figures 4a, 4b and 4c differs from the embodiment shown in figures 3a, 3b and 3c by a majority of heat sinks 2, N. A larger heat sink 2 with cooling fins and a smaller heat sink N also with cooling fins. The second heat sink, designated by N, represents a possible large number of N heat sinks integrally connected to the cover at different points of the cover. This enables simultaneously dissipate heat from a large number of electronic components arranged in the interior of an electronic device to an outside of the electronic device and additionally simultaneously protect the electronic device or rather the large number of electronic components from incoming and outgoing electromagnetic radiation.

Claims (8)

1. Patent claims 1. Electronic device (10) for a vehicle, with - a plastic cover (1), which plastic cover (1) delimits the electronic device (10) to an outside environment of the electronic device (10); - at least one electronic component (3) to be cooled, which electronic (3) component is arranged in an interior of the electronic device (10), characterized in that - the electronic device (10) comprises at least one plastic heat sink (2, N), which plastic heat sink (2, N) is integrally connected to the cover (1), which is thermally connectable to an electronic component (3) and which is configured to remove heat from an electronic component (3) and to dissipate the heat to the environment outside the electronic device (10), that - the at least one plastic heat sink (2, N) comprises a thermally conductive filler which is contained in the plastic of the heat sink (2, N), and that - the at least one plastic heat sink (2, N) additionally comprises an electrically conductive filler which is contained in the plastic of the heat sink (2, N).
2. 2. Electronic device (10) according to claim 1, characterized in that only a partial material section (4) of the at least one plastic heat sink (2, N) comprises an electrically conductive filler.
3. 3. Electronic device (10) according to one of claims 1 or 2, characterized in that additionally the plastic cover (1) comprises an electrically conductive filler.
4. 4. Electronic device (10) according to one of the preceding claims, characterized in that the electrically conductive filler is configured as a net structure or a lattice structure in and/or on the at least one plastic heat sink (2, N).
5. 5. Electronic device (10) according to one of the preceding claims, characterized in that the at least one plastic heat sink (2, N) is configured such that it extends at least partially around the electronic component (3) in the interior of the electronic device (10).
6. 6. Electronic device (10) according to one of the preceding claims, characterized in that the at least one plastic heat sink (2, N) comprises cooling fins.
7. 7. Method for manufacturing a plastic cover (1) for an electronic device (10) according to claim1, characterized in that the plastic cover (1) together with at least one plastic heat sink (2, N) is manufactured in an injection molding process or a 3D print process such that the at least one plastic heat sink (2, N) comprises a thermally conductive filler and additionally an electrically conductive filler.
8. 8. A vehicle comprising an electronic device (10) according to one of the claims 1 to 6.