US20050199367A1 - Method for heat dissipation in mobile radio devices, and a corresponding mobile radio device - Google Patents

Abstract

The present invention relates to a method for heat dissipation in mobile radio devices, with heat-radiating electrical components, whereby the heat-radiating components are brought into heat-dissipating contact with a metal film. The present invention further relates to a mobile radio device with heat-radiating electrical components, whereby each component is in effective heat-dissipating contact with a metal film.

Description

BACKGROUND OF THE INVENTION
• The present invention relates to a method for heat dissipation in mobile radio devices, and to a corresponding mobile radio device. An operating range with an environmental temperature generally of +55° C. is specified in mobile telecommunications terminals and in mobile radio devices, such as mobile telephones, PDAs and laptops. These mobile radio devices are constructed like a shell for the electronic components, wherein the temperature rises from shell to shell towards the components. The maximum temperature is functionally limited. The temperature close to the individual components in this case may be an environmental temperature of 82° C., while the temperature of the component itself may be up to 100° C. The electronic components convert the majority of the energy/power supplied to them to heat, which heats not only the component itself but also its immediate surrounding area. The power that is converted to heat is, accordingly, a power loss.
• In new, future mobile radio devices with the introduction of data services via GPRS with a so-called Class 10, the power with two transmission time slots is doubled, which also results in the power loss produced by the electronic components also being virtually doubled. The subdivision into “classes” relates to details of the configuration of the transmission and reception time slots. In Class 10, two transmission time slots are possible, wherein not only the transmission power but also the power loss is doubled.
• In even higher GPRS classes, such as GPRS Class 12, the power loss is up to a multiple of this. This results in a threat of the components being overheated after a certain operating time.
• The following table provides a rough overview of the GPRS classes:

  	Multislot	Transmission	Reception	Number of slots
  	Class	slots	slots	(usable)
  	1	1	1	2
  	.
  	.
  	.
  	8	1	4	5
  	.
  	.
  	.
  	10	2	4	5
  	.
  	.
  	.
  	12	4	4	5

• This type of problem has not occurred in the past in the field of mobile telecommunications since this technology is only now being introduced. In the past, mobile radio devices have been implemented and operated on the basis of GPRS Class 8.
• In other electronic devices, such as desktop computers, heat sinks or fans have been mounted on the temperature-critical components. When fitting heat sinks, care must be taken to ensure that good thermal coupling is provided between the heat sink and the electrical component which is heated by the power loss. In order to exclude air, as a poor thermal conductor, spaces between the corresponding component and the heat sink are filled with thermally conductive sheets or thermally conductive pastes.
• Furthermore, the distribution of the heat in electrical components can be influenced by a matched structure.
• Thermally conductive sheets and thermally conductive pastes are admittedly better thermal conductors than air, but they are also not adequate to ensure satisfactory heat dissipation for electrical components.
• Accordingly, the present invention seeks to provide a method which makes it possible to ensure good and satisfactory heat dissipation from electronic components in mobile radio devices, as well as a corresponding mobile radio device.
SUMMARY OF THE INVENTION
• Accordingly, a method is provided for heat dissipation in mobile radio devices having heat-emitting, electrical components, in which the heat-emitting components are brought into heat-dissipating contact with a metal foil.
• In one preferred embodiment of the method according to the present invention, the metal foil is corrugated and/or is structured in the form of a honeycomb. The use of a metal foil which is corrugated and/or is structured in the form of a honeycomb minimizes the resistance for heat dissipation. The capability of the metal foil that is corrugated and/or is structured in the form of a honeycomb to deform results in any intermediate spaces which occur being completely filled, thus ensuring optimum heat dissipation. The metal foil which is corrugated and/or in the form of a honeycomb can be arranged in an interlocking manner on the surfaces which can be brought into contact for heat dissipation.
• In a further preferred embodiment of the method according to the present invention, the metal foil is brought into contact with a heat sink. The heat sink may, for example, be a metallic body which either has a large area for radiated emission and/or a large volume as a heat sink.
• In another preferred embodiment of the present invention, the metal foil is itself used as a heat sink. The magnitude of the heat loss to be dissipated, in particular, determines whether the metal foil is itself adequate as a heat sink. The honeycomb and/or corrugated structure provided according to the present invention offers a very large heat-emitting surface area.
• Furthermore, the present invention covers a mobile radio device having heat-emitting electrical components, in which the components are each in heat-dissipating contact with a metal foil.
• The metal foil is preferably corrugated and/or has a honeycomb structure. The use of a metal foil which is corrugated or is structured in the form of a honeycomb enlarges the radiation-emitting surface area. The heat dissipation resistance is minimized, on the one hand, by the use of a metallic foil as well as by its structure, which is corrugated or is in the form of a honeycomb.
• Furthermore, in a further preferred embodiment of the mobile radio device according to the present invention, the metal foil is in heat-dissipating contact with a heat sink.
• In another preferred embodiment of the mobile radio device according to the present invention, the metal foil itself acts as a heat sink. Its honeycomb and/or corrugated structure results in it having a very large heat-emitting surface area.
• Furthermore, the present invention covers the use of a metal foil which is corrugated and/or is structured in the form of a honeycomb for heat dissipation from heat-emitting electrical components in mobile radio devices.
• Additional features and advantages of the present invention are described in, and will be apparent from, the following Detailed Description of the Invention and the Figures.
BRIEF DESCRIPTION OF THE FIGURES
• FIG. 1 shows a schematic illustration of one implemented embodiment of the method according to the present invention.
• FIG. 2 shows a schematic illustration of another implemented embodiment of the method according to the present invention.
• FIG. 3 shows a schematic illustration of a further implemented embodiment of the method according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
• FIG. 1 shows a printedcircuit board1 which is fitted on one side withcomponents2 which develop a large amount of heat. Aheat sink4 in the form of a cold plate is arranged on the other side of the printedcircuit board1 via suitable connectingelements3 which, for example, may be screws or rivets. During the fitting of theheat sink4, good thermal coupling between the heat sink and theelectrical components2 is a key factor ensuring that thecomponents2 are not excessively heated, which could possibly lead to destruction of thecomponents2. In order to avoid poor thermal conduction, ametal foil5 or a metal paste is, according to the present invention, inserted in the space which occurs between the printedcircuit board1 and theheat sink4.
• FIG. 2 shows another possible implementation of the method according to the present invention.FIG. 2 once again shows a printedcircuit board1 which is fitted with acomponent2, that produces heat losses, on one side. Ashielding cover6 is also provided above thecomponent2 for shielding. Aheat sink4 is arranged on the other side of the printedcircuit board1. This may be a heat sink, a battery or a chassis. According to the present invention, ametal foil5, which is corrugated and/or structured in the form of a honeycomb, is arranged in the resultant spaces between thecomponent2 or the printedcircuit board1 and theshielding cover6 or theheat sink4. The capability of themetal foil5, which is corrugated and/or structured in the form of a honeycomb, to deform allows very good contact for heat transfer. On the one hand, themetal foil5 may provide only the junction to aheat sink4, in this case, in the space between theheat sink4 and the printedcircuit board1. Furthermore, themetal foil5 could itself act as a heat sink. This is because the use of ametal foil5 with a corrugated or honeycomb structure considerably enlarges the radiation-emitting surface area.
• FIG. 3 shows a further possible implementation of the method according to the present invention. In this case as well,FIG. 3 shows a printedcircuit board1 with alossy component2 arranged on one side of the printedcircuit board1. Furthermore, aplastic part7 is arranged on the other side of the printedcircuit board1. Ametal foil5 which is in the form of a honeycomb and/or is corrugated is provided between theplastic part7 and the printedcircuit board1 and can be matched to the respective surfaces by virtue of its capability to be deformed well. By virtue of its structure, themetal foil5 itself has a very large heat-emitting surface area, which represents an additional beneficial factor.
• Although the present invention has been described with reference to specific embodiments, those of skill in the art will recognize that changes may be made thereto without departing from the spirit and scope of the present invention as set forth in the hereafter appended claims.

Claims (4)

1-3. (canceled)

4. A method for heat dissipation in mobile radio devices having heat-emitting electrical components, the method comprising:

providing that the heat-emitting electrical components be brought into heat-dissipating contact with a metal foil, wherein the metal foil is structured in at least one of corrugated form and honeycomb form; and

providing that the metal foil be brought into contact with a heat sink.

5. A mobile radio device having heat-emitting electrical components, comprising:

a metal foil which is structured in at least one of corrugated form and honeycomb form, wherein the heat-emitting electrical components are each in heat-dissipating contact with the metal foil; and

a heat sink, wherein the metal foil is in heat-dissipating contact with the heat sink.

6. A metal foil for heat dissipation from heat-emitting electrical components in a mobile radio device, comprising a structure which is in at least one of corrugated form and honeycomb form, wherein the heat-emitting electrical components are brought into heat-dissipating contact with the metal foil and the metal foil is in heat-dissipating contact with a heat sink.

Images